Chapter 3: Materials and Methods - Information and Library...

Ph.D Thesis (Pharmaceutical Sciences)

Shri Jagdishprasad Jhabarmal Tibrewala University, Jhunjhunu, Rajasthan

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3.0 MATERIALS AND METHODS

3.1 MATERIALS

The various materials utilized in this research work were obtained from different vendors

as enumerated in the subsequent sections.

List of materials used for the analytical work are mentioned in the Table 10.

Table 10: List of materials for Analytical work

List of materials used for the formulation development work are mentioned in the table 11,

Table 11: List of materials for Formulation development work

Sr.No. Drug/Excipients/Chemicals Characteristics Manufacturer/ Supplier

1. Topiramate API Hetero Drugs Ltd. India

2. Sugar spheres Core pellets -MB sugars & pharmaceutical, India -Pharm-a-spheres, Germany

3. Hypromellose 1 Binder/pore former Dow chemical, USA 4. Hypromellose 2 Binder/pore former Dow chemical, USA 5. Polyvinylpyrollidone Binder BASF 6. Mannitol Carrier Signet, India

Materials Manufacturer

Acetonitrile (HPLC Grade) Rankem, India

Milli-Q water Millipore, Germany

Methanol (HPLC Grade) Rankem, India

Trifluoroacetic acid SRL Mumbai, India

Topiramate working standard Hetero drugs, India

Impurity A

(2,3,4,5-Bis-O-(1-Methylethylidene)-β-D

-fructopyranose)

Hetero drugs, India



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7. Docusate sodium Solubilizer Techno drugs & Intermediates, India

8. Sodium benzoate Preservative Avantor Performance materials, India

9. Talc Anti-tacking agent Rio Tinto Minerals 10. Simethicone emulsion 30% Anti-foaming agent Rio-care 11. Ethylcellulose ER Polymer Dow chemical 12. Eudragit ER Polymer Evonik 13. Cellulose acetate ER Polymer Eastman 14. Extended release polymer 3

(ER-3) ER polymer 3 Manufacturer 1

15. Extended release polymer 4 (ER-4)

ER polymer 4 Manufacturer 2

16. Polyethylene glycol Pore former SD fine chem, India 17. Triethyl citrate Plasticizer Merck, Germany 18. Dibutyl sebasate Plasticizer Sigma Aldrich 19. Opadry 1 Moisture barrier coat Colorcon, India 20. Opadry 2 Moisture barrier coat Colorcon, India 21. Opadry 3 Moisture barrier coat Colorcon, India 22. Gelatin capsules Carrier for pellets Associated capsules 23. Purified water Solvent MilliQ purifier 24. Isopropyl alcohol Solvent Merck, Germany 25. Dichloromethane Solvent Merck, Germany 26. Acetone Solvent Merck, Germany

3.2 INSTRUMENTS

The various instruments and equipments utilized in this research work were obtained

from different vendors as enumerated in the subsequent sections.

List of instruments used for the analytical work are mentioned in the Table 12,

Table 12: List of instruments for Analytical work

Instruments Manufacturer Water bath sonicator PCI, Mumbai 0.45 micron Nylon filter paper MDI, Advanced microdevices pvt. Ltd. Ambala Cantt,

India Volumetric flask 25 mL, 50mL, 100 mL

J-sil, Agra

Measuring cylinder 25 mL J-sil, Agra Beaker 1000 mL J-sil, Agra Centrifuge Thermo scientific



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HPLC Column (Inertsil ODS-3, 250 x 4.6 mm, 5 µm or equivalent)

GL science Inc.

HPLC Column (Inertsil ODS-3, 250 x 4.6 mm, 3 µm or equivalent)

GL science Inc.

HPLC Column (Hypersil Phenyl, 250 x 4.6 mm, 5 µm or equivalent)

Thermo scientific

HPLC instrument Agilent 1200 series Pump Agilent G1311 A Pipettes 1 mL, 5mL, 10 mL J-Sil, Agra Data analysis software Chromeleon version 6.8 System Controller : Chromeleon version 6.8 Degasser : Agilent G1322A LC Detector (refractive index detector)

Agilent 1260 RID

Auto sampler : Agilent G1329A USP dissolution apparatus Type I (Basket)

Labindia disso 8000, India

USP dissolution apparatus Type II (Paddle)

Labindia disso 8000, India

List of equipments used for the formulation development work are mentioned in the table 13, Table 13: List of equipments for formulation development work

Sr. No.

Instruments Manufactures Model

1. Fluidized bed processor Pam Glatt GPCG 1.1, FBE 125C

2. High Performance Liquid Chromatography

Waters LC Module Plus

3. Karl Fisher Apparatus Metrohm 836 Titrando 4. Dissolution Test Apparatus Electrolab 2100C 5. Malvern Particle Size Analyzer Malvern - 6. IR Spectrometer Perkin Elmer Spectrum One 7. Differential scanning calorimetry Perkin Elmer DSC 8500 8. Tapped Density Tester Electrolab ETD-1020 9. LOD (Loss on drying) tester Mettler Toledo HB-43 10. pH Meter Thermo 720A 11. Ultrasonic Bath Aarkey Labtronic Power Sonic 420 12. Analytical Balance Mettler Toledo XS-205 13. Weighing Balance Mettler Toledo - 14. Overhead Stirrer Remi - 15. Sieves Atlanto enterprises - 16. Blister Packing Machine Mechtek EZEE BLIST



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3.3 ANALYTICAL METHODS:

3.3.1 ASSAY METHOD

Note: Use all solvents of HPLC grade

Reference: In-House

Preparation Mobile phase:

Mix Acetonitrile and water in 50:50 v/v ratio by sonication and degassing for 10

minutes. Filter through 0.45µm Nylon filter.

Diluent: Mobile phase.

Preparation of standard solution:

Weigh accurately 25 mg of Topiramate working standard and transfer into 25 mL

volumetric flask, add 15 mL of diluent and sonicate it for 10 minutes, dilute and

make up the volume with diluent.

Preparation of test solution:

Weigh accurately the capsule content equivalent to 50 mg of Topiramate and

transfer it into 50 mL of volumetric flask, add 30 mL of diluent and sonicate it for

20 minutes, dilute and make up the volume with diluent.

Chromatographic conditions:

Column : Inertsil ODS – 3, 250 x 4.6 mm, 5 µm or equivalent Column temperature : 55ºC Optical unit temperature

: 55ºC

Flow rate : 0.6 mL/min Detection : Refractive index detector Injection volume : 20 µL Run time : 15 minutes

Procedure:

Inject 20 µL portion of the Diluent as blank, standard preparation (five times) and

test preparation into the chromatograph, record the chromatograms and measure

the responses for major peak.



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System suitability:

(a) Tailing factor from standard chromatogram should not be more than 2.0.

(b) The relative standard deviation for five replicate injections of standard

preparation should not be more than 2.0 %

(Refer annexure I for specimen chromatogram)

Calculation:

Quantity of Topiramate A Ws 50 Aw P

present in the portion of the = ------- x ------- x ------- x -------- x -------- x100

capsule as % of labeled amount B 25 Wt 100 L

A = Peak area of Topiramate for test preparation

B = Peak area of Topiramate for standard preparation

Ws = Weight of Topiramate standard taken, in mg.

P = Potency of Topiramate standard

L = Labeled amount of Topiramate, in mg, per capsule.

Wt = Weight of Topiramate ER capsule content taken for test preparation.

Aw = Average weight

Assay Chromatograms:

Figure 8: BLANK-ASSAY

Minutes

0 2 4 6 8 10 12 14 16 18 20

mA

U

0

1000

2000

3000

mA

U

0

1000

2000

3000

RID: RI Signal

Retention TimeName



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Figure 9: STANDARD SAMPLE-ASSAY

Minutes

0 2 4 6 8 10 12 14 16 18 20

mA

U

0

5000

10000

15000

20000

mA

U

0

5000

10000

15000

20000

8.80

1 T

OP

IRA

MA

TE

RID: RI SignalRetention TimeName

Figure 10: TEST SAMPLE –ASSAY

Minutes

0 2 4 6 8 10 12 14 16 18 20

mA

U

0

20000

40000

60000

80000

mA

U0

20000

40000

60000

80000

8.77

9 T

OP

IRA

MA

TE




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Figure 11: PLACEBO SAMPLE –ASSAY

Minutes

0 2 4 6 8 10 12 14 16 18 20

mA

U

0

20000

40000

60000

80000

mA

U

0

20000

40000

60000

80000


3.3.2 DISSOLUTION TEST METHOD

Reference: In-House


Preparation of Mobile phase:

Mix 500 mL of water and 500 mL of Methanol in 1000 mL beaker and add 1 mL

of Trifluoroacetic acid, mix well and sonicate it for 5 minutes. Filter through 0.45

µ Nylon filter.

Preparation of Standard solution:

Weigh accurately 27.5 mg of Topiramate Working standard and transfer into 50

mL of volumetric flask, add 15 mL of dissolution media and sonicate it for 5

minutes and dilute it up to the mark with media. Pipette out 10 mL of this solution

in to 25 mL volumetric flask and dilute to volume with dissolution media.


(1) Transfer 900 mL of Dissolution media into the each dissolution vessel.

(2) Lower the baskets, with capsules into each of the six dissolution vessels.



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(3) Withdraw the samples in auto sampler tubes at respective time intervals,

centrifuge a portion of the solution at 5000 RPM for 5 minutes and filter

through 0.45µ Nylon filter.


Column : Hypersil Phenyl, 250 x 4.6 mm, 5µm or equivalent Column temperature : 40ºC Optical unit temperature

: 40ºC

Detection : Refractive index detector Flow rate : 1.0 mL/min Injection volume : 100 µl Run time : 10 min

Dissolution parameters:

Medium : Purified water

Quantity : 900 mL

Apparatus : USP I (Basket)

RPM : 100

Temperature : 37 ± 0.5 °C

Time : 1, 2, 3, 4, 6, 8, 10, 12, 16, 18, 20, 24 hrs

Procedure: Inject 100µl portion of the dissolution medium as blank, standard preparation

(five times) and both test preparation into the chromatograph, record the

chromatograms and measure the responses for major peak.

System suitability:

(a) Tailing factor from standard chromatogram should not be more than 2.0.

(b) The relative standard deviation for five replicate injections of standard

preparation should not be more than 2.0 %

Calculation:

Quantity of Topiramate A Ws 10 900 P

dissolved as % of labeled amount = -------- x ------- x ------- x ------- x ------- x 100

B 50 25 L 100



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Where,

A = Peak area of Topiramate (API) for Test preparation.

B = Peak area of Topiramate for Standard preparation.

Ws = Weight of Topiramate standard taken, in mg for standard preparation.

P = Potency of Topiramate

L = Labeled amount of Topiramate, in mg, per capsule.

Calculation of Correction factors: % of API present in sampled volume after 1st time interval, F1 = (D1 / 900) x 10

% of API present in sampled volume after 2nd time interval, F2 = (D2 / 900) x10

% of API present in sampled volume after 3rd time interval, F3 = (D3 / 900) x10

% of API present in sampled volume after nrd time interval, Fn = (Dn / 900) x10

Calculation of Corrected results:

For 1st time interval = D1 (No correction required).

For 2nd time interval = D2 + F1

For 3rd time interval = D3 + F1 + F2

For 4th time interval = D4 + F1 + F2 + F3

For nth time interval = D4 + F1 + F2 + F3……….+Fn

Where n=1,2,3,4,……..

Stage Number Tested Acceptance Criteria

L1 6 No individual value lies outside each of the stated range and no

individual value is less than the stated amount at the final test time

L2 6

Average of 12 units(L1+L2) lies within each of the stated ranges and is

not less than the stated amount at the final time; none is more than

10% of labled content outside each of the stated ranges; and none is

more than 10% of labeled content below the stated amount at the final

test time.



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L3 12

The average value of the 24 units (L1 + L2 + L3) lies within each of

the stated ranges, and is not less than the stated amount at the final test

time; not more than 2 of the level 24 units are more than 10% of

labeled content outside each of the stated ranges; is not more than

2 of the 24 units are more than 10% of labeled content below the

stated amount at the final test time; and none of the units is more than

20% of labeled content outside each of the stated ranges or more

than 20% of labeled content below the stated amount at the final test

time.

Dissolution Chromatograms:

Figure 12: BLANK dissolution chromatogram

M in u te s

0 1 2 3 4 5 6 7 8 9 1 0

mA

U

0

2 0 0 0

4 0 0 0

6 0 0 0

mA

U

0

2 0 0 0

4 0 0 0

6 0 0 0

R ID : R I S ig n a lR e te n tio n T im eN a m e

Figure 13: Standard dissolution chromatogram

M in u te s

0 1 2 3 4 5 6 7 8 9 1 0

mA

U

0

2 5 0 0

5 0 0 0

7 5 0 0

1 0 0 0 0

mA

U

0

2 5 0 0

5 0 0 0

7 5 0 0

1 0 0 0 0

6.68

9 T

opira

mat

e

R ID : R I S ig n a lR e te n tio n T im eN a m e



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Figure 14: Test dissolution chromatogram

M inutes

0 1 2 3 4 5 6 7 8 9 10

mA

U

0

2500

5000

7500

10000

mA

U

0

2500

5000

7500

10000

6.62

4 T

opira

mat

e

RID: RI S ignalRetention Tim eNam e

3.3.3 RELATED SUBSTANCES TEST METHOD


Reference: In-House Preparation of mobile phase:

Mix 0.05 % Trifluoroacetic acid, Acetonitrile and Methanol in the ratio of

50:30:20 v/v/v, sonicate and degas it for 10 minutes.

Preparation of 0.05 % Trifluoroacetic acid:

Add 0.5 ml of Trifluoroacetic acid to 1000 ml of MillQ water.

Preparation of diluent:

Mix Acetonitrile and water in the ratio of 50:50 v/v.

Preparation of standard stock solution:

Weigh accurately 40 mg of Topiramate working standard and transfer it into 100

ml volumetric flask. Add 70 ml of diluent, sonicate to dissolve for 5 minutes and

dilute to volume with diluent.

Preparation of standard solution:

Transfer 5 ml of the standard stock solution into 50 ml volumetric flask and

dilute to volume with diluents.



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Preparation of system suitability solution:

Weigh accurately and transfer 3 mg of Impurity A and 1000 mg of Topiramate

working standard into 50 ml of volumetric flask. Dissolve and dilute to volume

with diluent.


Weigh accurately the capsule content equivalent to 1000 mg of Topiramate and

transfer it into 50 ml volumetric flask. Add 30 ml of diluent, sonicate it for 30

minutes and make up to volume with Diluent. Mix well and centrifuge a portion

of solution at 5000 rpm for 10 minutes. Filter the supernatant solution through

0.45µm nylon membrane filter.

Preparation of placebo solution:

Weigh accurately placebo equivalent to 1000 mg of Topiramate and transfer it

into 50 ml volumetric flask. Add 30 ml of diluent, sonicate it for 30 minutes and

make up to volume with Diluent. Mix well and centrifuge a portion of solution at

5000 rpm for 10 minutes. Filter the supernatant solution through 0.45µm nylon

membrane filter.


Procedure:

Inject 50 µl of diluent as blank, placebo solution, standard solution in duplicate

and test solution in the liquid chromatograph and record the chromatogram.

Column : Inertsil ODS – 3, 250 x 4.6 mm, 3 µm or equivalent

Column temperature : 50ºC

Optical unit temperature

: 55ºC

Flow rate : 0.6 mL/min

Detection : Refractive index detector

Injection volume : 50 µL

Run time : 30 minutes

Peak width : 0.05 min (response time)



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System suitability:

(a) Resolution between Impurity A and Topiramate should not be less than 1.0

(b) Ratio of peak areas of two standard injections should be between 0.9 to 1.1.

(c) Theoretical plates should not be less than 2000.

(d) Tailing factor from standard chromatogram should not be more than 2.0.

(Refer annexure III for specimen chromatogram)

Relative retention time of impurity A: 0.91

Calculation:

A Ws 5 50 Aw P

%, impurity = ------ x ------ x ------- x -------- x ------ x ------- x 100

B 100 50 Wt L 100

Total impurities = Sum of all the known impurities and unknown impurities.

Where,

A = Peak area of impurity obtained from test solution.

B = Average peak area of Topiramate in the chromatogram from duplicate injection of standard solution.

Ws = Weight of Topiramate standard taken, in mg for standard preparation.

P = Potency of Topiramate.

L = Labeled amount of Topiramate in mg, per capsule

Aw = Average weight



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Related substance (RS) chromatograms:

Figure 15: BLANK RS chromatogram

Figure 16: Placebo sample RS chromatogram



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Figure 17: Standard sample RS chromatogram

Figure 18: Test sample RS chromatogram



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3.4 PREFORMULATION STUDIES:

A detailed understanding of the properties of drug substances is essential for minimizing

formulation problems in later stage of development which will ultimately help in

reducing the development cost and in decreasing the product time to reach in market (i.e.,

from drug substance to drug product). Preformulation data of physical and chemical

properties of drug and excipients helps us to develop desirable dosage forms. The overall

objective of the preformulation testing is to generate information useful to the

formulator in developing stable dosage forms.

• General properties of API

• API authentication

• API characterization

• API stability data

• Excipient-compatibility studies

• Characterization of reference product

3.4.1 GENERAL PROPERTIES OF API

Table 14: General properties of Topiramate API ATTRIBUTE DESCRIPTION

Structural Formula

Manufacturer Hetero Drugs Limited Chemical Name 2,3:4,5Di-O-isopropylidene-β-D-fructopyranose sulfamate Therapeutic category Anticonvulsant Molecular Formula C12H21NO8S Molecular Weight 339.36 Description White to off-white powder Physical Characteristics It is a white crystalline powder with a bitter taste Polymorphism Topiramate does not exhibit Polymorphism



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Isomerism Topiramate exhibit isomerism Solubility Freely soluble in Dichloromethane Hygroscopicity Sample is not Hygroscopic (Increased upto 0.13% to the

original weight, viz. 1 g) pH 4.5 - 6.0 pKa 10.56 Melting range 122.0°C to 126.0°C Storage Conditions In air tight container at controlled room temperature BCS Class Class II LogP/Hydrophobicity 0.88

3.4.2 API AUTHENTICATION

a) Physical characteristics

The sample of Topiramate API was checked for its physical characteristics like

appearance, color, odour and taste.

b) Differential scanning calorimetric (DSC) studies

The DSC thermogram of pure topiramate was recorded using a DSC equipped with a

computerized data station. All samples were weighed and heated in a closed pierced

aluminum pan at a scanning rate of 10°C/min between 0ºC and 200°C and nitrogen flow

of 25 ml/min.

c) Infra Red (IR) spectrum

The dry sample of pure topiramate API was mixed with IR grade KBr in the ratio of 1:30.

This mixture was compressed in the form of a pellet by applying 10 tons of pressure by

hydraulic press. The pellets were scanned over a wave number range of 3600 to 600 cm-1 in

FTIR instrument and spectral analysis was done. The obtained spectrum was then

compared with standard group frequencies of Topiramate API.

d) X-Ray diffraction of Topiramate API

X-ray diffraction study was performed on pure topiramate API, this test was

performed to identify the polymorphic form of the API. Topiramate API was mixed

gently to break the agglomerates of the API, then load into the sample holder of the



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XRD instrument which was attached with computerized data station and check the

polymorphism

e) Ultra-violet spectrum of Topiramate API

0.002% w/v solution of Topiramate in methanol was scanned from 400 to 200 nm

and checked the ultra-violet spectrum.

f) Carbon nuclear magnetic resonance spectrum:

Carbon-13 decoupled nuclear magnetic resonance spectrum of Topiramate was

obtained on a 300 MHz NMR using CD3OD as the sample solvent at 27ºC.

g) Mass spectrum of Topiramate API:

The mass spectrum of Topiramate was obtained using Mass spectrophotometer.

h) Optical rotation of Topiramate API:

Topiramate is a chiral compound. Optical rotation of the Topiramate APL was

checked by using Polarimeter.

3.4.3 API CHARACTERIZATION

a) Particle size analysis

Topiramate’s particle size distribution was determined by Malvern Mastersizer by dry

dispersion method as particle size of API plays an important role in the manufacturing of

drug layered pellets.

b) Solubility of Topiramate API

The solubility studies of Topiramate API in different solvents and different buffer at

different temperatures were evaluated.

Shake flask method for determination of saturation solubility of topiramate API was

chosen.



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• Perform the solubility experiment at room temperature (about 20 to 270C) or

at required temperature (generally at 370C)

• Take 100 ml of solvent or medium in which the solubility of drug substance

is to be established into a 250 ml stoppered conical flask.

• Add an accurately weighed amount of drug substance. The amount to be

added initially can be determined based on any literature search or add about

10 mg.

• Mix the solution by swirling the conical flask with stopper on rotary shaker

and shake to dissolve material completely, go on adding weighed amount

(about 100 mg) of drug substance until the medium shows resistance towards

dissolving the drug substance.

• Continue the shacking of flask for one more hour from the point of resistance

towards solubility.

• If drug substance does not dissolve completely even after one hour shacking,

add an excess amount of drug substance (add an amount in excess) and shake

for 24 hours on rotary shaker.

• If drug substance dissolves completely, add further weighed amount and

again shake for one hour on a rotary shaker. Check the presence of drug in

insoluble form, check the pH of the solution and record the same.

• Centrifuge a portion of the above solution and use the clear centrifuge for

analysis or if the solution could not be made clear by centrifuge, use a 0.45

µm filter discarding an initial portion of the filtrate.

• Calculate the “total amount of the drug substance added” by adding all the amounts

added (wt).

• Estimate the content of the drug substance dissolved either by an UV or by an HPLC

method (where applicable or if required by stability indicating assay method)

perform study in duplicate.

• Prepare standard solution preferably in the same medium. The concentration of the

standard solution shall be decided based on ‘easy’ solubility of the drug substance.

The concentration of the standard shall be such that level the solubility of the drug



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substance shall be complete and shall give an optimum response for the method of

detection / quantification.

• Dilute the above test solution if necessary to get a concentration approximately equal

to that of standard preparation.

• Calculate the amount of the drug substance dissolved by using the following

formula.

The quantity of the drug substance dissolved (Q) in percentage (w/v).

Q = A x C x 100 x V2 x V4

B x Wt x V1 x V3

C = Concentration of standard solution in mg/mL

A = Response of the test solution

B = Response of the standard solution

Wt = Total amount of drug substance added in mg

V1 = Volume of filtered test solution taken in mL

V2 = Diluted volume in mL

V3 = Volume of the diluted test solution taken in mL

V4 = Diluted volume in mL

• The actual amount of drug substance dissolved (m) in mg

m = Q x Wt

100

• The solubility of the drug substance (S) in mg/mL in the solvent/medium

tested

S = m/100

• Verify the solubility obtained against the quantity dissolved easily. The

solubility data obtained shall be equal to or more than the easily established

quantity. If the solubility data is less than the easily solubilized quantity, then

study the stability of the drug in the respective media and interpret the results.

Solution stability data needs to be established in those media where drug is

found to be degrading. Based on the stability study, if necessary repeat by

taking necessary precautions.



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Table 15: Saturation Solubility profile of Topiramate API Sr. No. Type of media mg/ml

1 Water 11.477 2 pH 2.1 12.042 3 pH 3.0 11.671 4 pH 4.5 11.558 5 pH 5.5 10.61 6 pH 6.8 11.124 7 pH 7.4 11.121

� Solubility in different solvent such as water, methanol, 0.1N sodium hydroxide,

dimethyl formamide, acetone & dichloromethane were evaluated at 27ºC and

40ºC temperature.

� Solubility in different buffer such as pH 1.2, pH 4.0, pH 7.0, pH 9.2 and pH 12.0

were evaluated at 27ºC and 40ºC temperature.

c) Hygroscopicity study

Hygroscopicity study of the Topiramate API was done in different storage conditions i.e.,

at 55% and 80 % of relative humidity (%RH) for 24 hours at 25°C.

Preparation of saturated solution: Excess amount of salt was dissolved in small amount of

purified water with continuous stirring .Based on requirement; extra amount of salt was

added into the solution. It was stirred continuously until an un-dissolved solid appears at

the bottom. At this point, the solution is said to be saturated.

Table 16: Standard salt solution for specific Relative humidity

Salts to be used Relative humidity ( % RH) at 25°C Lithium Chloride 11.30 ± 0.27 Potassium acetate 22.51 ± 0.27 Magnesium chloride (or ) Calcium chloride 32.78 ± 0.16 Potassium carbonate 43.16 ± 0.39 Magnesium nitrate 52.89 ± 0.22 Sodium chloride 75.29 ± 0.12 Potassium chloride (or) Potassium bromide 84.34 ± 0.26 Ammonium chloride or Ammonium sulphate 80 ± 2.00



109

Procedure: 50 mL saturated salt solution of ammonium chloride or ammonium sulphate

was placed in desiccators. Hygrometer was also placed to measure humidity (Limit: 80%

RH ± 2.00) and desiccator was sealed with its lid. Desiccators were allowed to stand at

room temperature for about 12 hrs. Glass petridish with dimensions approximately 50

mm in external diameter and 15 mm in height with its cover was used in this study.

Weight of the empty petridish together with its cover was recorded as (W1) g. Four

petridishes for four time points (2,4,8 & 24 hour) at each humidity condition were taken

and 1.0 gm sample in each petridish was placed. These petridishes were covered and

weight (W2) g was recorded. Sample was uncovered and cover was placed at the bottom

of the petridish. These uncovered petridishes were placed in the desiccators and

desiccators were sealed with its lid. Sample was allowed to get an exposure for 24 hrs.

Petridishes were removed together with covers and weights are recorded as W3-4, W3-12

and W3-24 at 4, 12 and 24 hrs, where W3-4, W3-12 and W3-24 represent the weight of

sample and petridish at 2, 4, 8 and 24 hours respectively.

• Weight of empty petridish + cover = (W1) ………………g

• Weight of petridish + Sample + cover = (W2) …………..g

• Weight of petridish + Sample + Cover at nth time = (W3) …g [n= 1 to 24 hr]

• % Increase in weight = {(W3 - W2)*100}/(W2-W1)

Results are interpreted as follows:

• Deliquescent: Sufficient water is absorbed to form a liquid.

• Very hygroscopic: Increase in weight is equal to or greater than 15 %.

• Hygroscopic: increase in weight less than 15 % and equal to or greater than 2%.

• Slightly hygroscopic: increase in weight less than 2 % and equal to or greater than

0.2%.

d) Physical properties of API powder

Drug was evaluated for the following powder characteristics.



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• Angle of repose

Angle of repose is a characteristic related to inter-particulate friction or resistance to

movement between particles. The angle of repose is the constant three dimensional angle

of a cone-like pile of material formed on a horizontal base.

Procedure: A funnel height should be maintained approximately 2-4 cm from the top

of the powder pile as it is being formed in order to minimize the impact of falling

powder on the tip of the cone. The base of the powder should be free of vibration. Vary

the height of the funnel to carefully build up a symmetrical cone of powder.

Angle of repose (θ) = tan -1 h/r

Table 17: Flow property and angle of repose as per USP general chapter (1174)

Flow Property Angle of Repose (degrees) Excellent 25 - 30

Good 31 - 35 Fair: aid not needed 36 - 40

Passable: may hang up 41 - 45 Poor: must agitate or Vibrate 46 - 55

Very Poor 56 - 65 Very, Very Poor > 66

• Bulk Density

Powder weighing 20.90 gm of the Topiramate API was taken after passing through #40

ASTM sieve into 100 ml measuring cylinder without tapping and measure the untapped

volume of the API (96 ml). Volume occupied by the powder was noted without disturbing

the cylinder and bulk density was calculated by the following equation:

Bulk Density = drugbulk of Volume

drugbulk of Mass

Parameter Equipment ID. � FD/BD/005 a) Bulk density (ρbulk) (gm/ml) 0.217

The experiment was performed in triplicate.



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• Tapped Density

Powder weighing Powder weighing 20.90 gm of the Topiramate API was taken after

passing through #40 ASTM sieve into 100 ml measuring cylinder. The cylinder was then

subjected to a fixed number of taps 500 drops and check the volume of the API (72 ml),

then 750 drops (69 ml) and finally tapped for 1250 drops (68 ml) until the powder bed

volume had reached the minimum level. The final volume was recorded and the tap

density was calculated by the following equation:

Tapped Bulk Density = on tapping drugbulk of Volume

drugbulk of Mass

Parameter Equipment ID. � FD/BD/005 a) Tapped density (ρTap) (gm/ml) 0.307

The experiment was performed in triplicate.

Table 18: Bulk and Tap density of Topiramate API

Sr. No. Parameter Results 1 Bulk density 0.217 2 Tap density 0.307

• Compressibility

The compressibility index has been proposed as an indirect measure of bulk density,

size and shape, surface area, moisture content, and cohesiveness of materials. All of

these can influence the observed compressibility index. The compressibility index of

the powder blend was determined using Carr’s compressibility index:

% Compressibility = 100 Density Tapped

Density Bulk -Density Tapped ×

• Hausner’s Ratio

The Hausner’s ratio is determined by measuring both the bulk volume and tapped volume

of a powder. A Hausner’s ratio greater than 1.25 is considered to be an indication of poor

flowability. Formula used was as follows:



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Hausner’s Ratio = DensityBulk

Density Tapped

Table 19: Standard range of Carr’s Index and Hausner’s Ratio and respective flow characteristics

Carr's Index (%) Flow Character Hausner’s Ratio ≤10 Excellent 1-1.11

11-15 Good 1.12-1.18 16-20 Fair 1.19-1.25 21-25 Passable 1.26-1.34 26-31 Poor 1.35-1.45 32-37 Very poor 1.46-1.59 ≥38 Very very poor ≤ 1.6

e) Packing and storage condition for Topiramate API:

should be stored in tightly-closed containers at controlled room temperature (59° to 86°F,

15° to 30°C). Protect from moisture.

f) Chemical Properties of Topiramate

pKa : 11.9

pH : pH of a 1% aqueous solution of Topiramate is 5.51

Solubility : 7.8mg/ml in water

g) Biological Properties:

Partition coefficient: Log P 1.29

Biopharmaceutics Classification: BCS Class II

3.4.4 API STABILITY STUDY

Stability studies were initiated for 3 lots of API (Batch No. TA0021008, TA0031008 and

TA0041008) as per the ICH Q1A guidelines at 40ºC±2ºC / 75±5%RH, 30ºC±2ºC /

65±5%RH and 25ºC±2ºC / 60±5%RH.

The condition under which the samples were placed for the stability and analyzed were

providing in the given table.



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Table 20: Storage condition of Topiramate API stability study

Study Storage condition Frequency Accelerated 40ºC±2ºC / 75±5%RH 0, 1, 2, 3, 4, 5, 6 Intermediate 30ºC±2ºC / 65±5%RH 0, 1, 2, 3, 4, 5, 6, 9, 12 Long Term 25ºC±2ºC / 60±5%RH 0, 1, 3, 6, 9, 12, 18, 24, 36, 48, 60

Packing of Topiramate API was in double polythene bags (inner transparent, outer black).

The inner and outer bag were tied with plastic tag individually and kept the sample in

HDPE container with Silica gel pouch.

The stability samples were analyzed as per the standard test procedures provided in the

section “3.3 Analytical methods”. The methods adopted for the stability studies are

stability indicative which were established based on the degradation studies carried out for

the product Topiramate.

Typical parameters followed for the Forced degradation studies is provided in the

following pages.

Topiramate sample (B.No. TA0051108) was degraded under various conditions mentioned

in the following Table 21,

Table 21: Force degradation study Protocol

Sr. No. Name of the Degradation

Sample preparation

1 Mother (as such sample) ------

2 Thermal degradation 5 g Topiramate API was taken in petridish and place

the petridish in an oven at 80ºC for 2 hours. After 2

hours, petridish was cooled to room temperature and

samples were collected for analysis.

3 Humidity degradation 5 g Topiramate API was taken in petridish and place

the petridish in a dessicator containing water for

about 48 hours and samples were collected for

analysis.



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4 Photo degradation 5 g Topiramate API was taken in petridish and

exposed to light providing an overall illumination of

not less than 1200 KLux hours and an integrated

energy of not less than 200 Watt-Hours/ Sq. mts.

5 Water degradation 5 g Topiramate API was taken in 200mL RB flask,

then 100mL of water was added and kept on bench

top for about 1 hour. Further dilution of the solution

was done as per the test sample concentration. [Note:

semi liquid samples was filtered before analysis].

6 Acid degradation 5 g Topiramate API was taken in 200mL RB flask,

then 100mL of 0.01N HCl was added and kept on

bench top for about 1 hour. Further dilution of the

solution was done as per the test sample

concentration. [Note: semi liquid samples was

filtered before analysis].

7 Base degradation 5 g Topiramate API was taken in 200mL RB flask,

then 100mL of 0.1N NaOH was added and reflux for

1/2 hour on oil bath at 100ºC. Further dilution of the




8 Peroxide degradation 5 g Topiramate API was taken in 200mL RB flask,

then 100mL of 0.01% of H2O2 was added and kept on

bench top for about 1 hour. Further dilution of the




The details of the degradation were recorded. The mother sample, Thermal degradation

sample, Humidity degradation sample, Photo degradation sample, Water degradation



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sample, Acid degradation sample and Peroxide degradation sample of Topiramate were

analyzed for Description, Identification by IR, Water content by KF, Related substances by

HPLC and Assay on anhydrous basis by HPLC and for base degradation sample of

Topiramate were analyzed for Description,Related substances by HPLC and Assay on

anhydrous basis by HPLC.

Table 22: Force degradation strategies

Sr. No. Name of the Degradation Period of exposure

1 Mother (as such sample) ------

2 Thermal degradation 2 hours

3 Humidity degradation 48 hours

4 Photo degradation 22 hours

5 Water degradation 1 hour

6 Acid degradation 1 hour

7 Base degradation 1/2 hour

8 Peroxide degradation 1 hour

3.4.5 REFERENCE PRODUCT CHARACTERIZATION

Before starting the actual formulation work reference product was evaluated for

physicochemical properties, Pack evaluation, Reverse engineering to find out probable

composition and in-vitro drug release test.

Since Topiramate modified release (MR) capsules shall pass the Gastro-intestinal tract

after administration, hence multi-media dissolution study in 0.01N hydrochloric acid

(pH 2.1) followed by pH 6.8 phosphate buffer was selected as discriminatory

dissolution condition. This dissolution condition was applied during initial

development to arrive upon very close composition to get similar dissolution profile as

compared to reference product (Trokendi XR). The complete discriminatory

dissolution condition is mentioned in the following table 23.

Table 23: In-Vitro Dissolution Test Protocol (For Discriminatory dissolution test)

Dissolution apparatus USP Type I (Basket) apparatus



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Dissolution medium 0.01N HCl (pH 2.1) followed by pH 6.8 phosphate buffer

Speed (RPMs) 100 Media volume (ml) 500ml - 0.01N HCL, followed by volume make

upto 900 ml for pH 6.8 Phosphate buffer Recommended sampling times (hr) 0,2,4,6,8,10, 12, 14, 16, 18 & 24 Temperature conditions 37.5°C

As per office of generic drugs (OGD) of US-FDA, the recommended dissolution

condition is in pH 7.5 phosphate buffer. Hence we have selected this dissolution

condition also as quality control dissolution test method for routine analysis of finished

product and stability sample analysis. The complete dissolution test condition for routine

analysis as per OGD recommendation is mentioned in the following table .

Table 24: In-Vitro Dissolution Test Protocol (For Routine analysis)

Dissolution apparatus USP Type II (Paddle) apparatus Dissolution medium pH 7.5 phosphate buffer Speed (RPMs) 50 Media volume (ml) 750 ml for pH 7.5 Phosphate buffer Recommended sampling times (hr) 0,1, 2, 3, 4, 6 & 8 Temperature conditions 37.5°C

3.4.6 EXCIPIENT COMPATIBILITY

Drug-excipients compatibility study was carried out to find out the suitability of the

excipients listed below for the development of prototype formulation. The blends of

the drug substance and commonly used excipients were subjected to condition of

temperature and humidity viz; 40°C / 75% RH and 50°C for 1 month. Various

proportions of drug substance and excipients were used, as shown in following table.

These mixtures were kept in hermetically sealed clear glass vials. After 1 month assay

and related substances tests were performed.

Table 25: Drug excipients compatibility protocol

Sr.No Excipient Vial Ratio gm Total gms



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1. Topiramate (API) 1 ---- 1 1 2. Sugar spheres + API 2 9:01 9:01 10 3. Celphere 507 + API 3 9:01 9:01 10 4. L-HPC + API 4 1:01 1:01 2 5. HPMC LV+ API 5 1:01 1:01 2 6. Polyvinyl pyrrolidone + API 6 1:01 1:01 2 7. Simethicone 30% + API 7 1:01 1:01 2 8. Talc+ API 8 1:01 1:01 2 9. Surelease 80%+ API 9 1:01 1:01 2 10. Kollicoat 30 D + API 10 1:01 1:01 2 11. Ethyl cellulose + API 13 1:01 1:01 2 12. Cellulose Acetate + API 14 1:01 1:01 2 13. Triethyl citrate+ API 15 1:01 1:01 2 14. PEG4000+ API 16 1:01 1:01 2 15. Triacetin+ API 17 1:01 1:01 2 16. Hydroxypropyl B-CD + API 18 1:01 1:01 2 17. Vitamin E TPGS+ API 19 1:01 1:01 2 18. SLS+ API 20 1:01 1:01 2 19. Docusate sodium+ API 21 1:01 1:01 2 20. Opadry II + API 22 1:01 1:01 2 21. Opadry 200 + API 23 1:01 1:01 2 22. Opadry AMB + API 24 1:01 1:01 2 23. IPA+ API 25 1:01 1:01 2 24. MDC+ API 26 1:01 1:01 2 25. Acetone +API 27 1:01 1:01 2 26. Water + API 28 1:01 1:01 2 27. Gelatin capsule + API 29 1:01 1:01 2 28. HPMC capsule + API 30 1:01 1:01 2 29. Composite + API 31 9:01 9:01 10

3.5 FORMULATION DEVELOPMENT STUDIES:



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The main objective of the research activity was to design stable, effective

pharmaceutically equivalent formulation of Topiramate modified release capsules 25mg,

50mg, 100mg & 200 mg. Initial development was started with Topiramate modified

release capsules 50mg by considering the fact that maximum dose of the immediate

release tablets is 25 mg, hence modified release capsules shall be 50mg as reference

product was not approved at that time. Later, on 16th August 2013, U.S. Food and Drug

Authority’s (FDA) approved reference product of Topiramate extended release tablets,

brand name “Trokendi XR”, manufacturer is Supernus Pharmaceuticals Inc.

Trokendi XR has launched with 4 strengths, 25mg, 50mg, 100mg & 200mg and

Reference listed drug (RLD) is Trokendi XR 200mg. As per the U. S. Food and Drug

Authority’s recommendation generic product of Topiramate modified release capsules

200mg should have comparable in-vitro dissolution profile and in-vivo plasma profile

with that of marketed product Trokendi XR’s 200mg Extended release capsules as 200mg

strength is RLD and other lower strengths should be dose-weight proportional

composition with comparable in-vitro dissolution studies between respective lower

strengths based on F2 value (similarity factor) calculation.

Reference product’s strategy is - A sustained release formulation of topiramate for oral

administration to a mammalian subject comprising an immediate release pellets portion

(IR), a first extended release pellets portion (XR1), and a second extended release pellets

portion (XR2) as per Patent no. US8298576 which will be expiring on Mar 18, 2029.

Hence, to overcome this innovator’s patent - A single pellets portion containing multiple

coating layers was proposed for formulation development. The step by step formulation

development approaches is as follows:

1. Reference product’s patent evaluation

2. Choice of excipients

3. Core pellets type and size size selection

4. Seal coat on core pellets optimization



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5. Drug layering optimization

6. Modified release coating optimization

7. Moisture barrier coating optimization

3.5.1 REFERENCE PRODUCT’S PATENT EVALUATION

As per the U.S. FDA’s orange book status, Reference product has three patents, among

which 2 patents are expiring on 16th Nov 2027 and one patent is expiring on 18th Mar

2029. The main claim of the Reference product patent is “A sustained release formulation

of topiramate for oral administration to a mammalian subject comprising an immediate

release pellets population (IR), a first extended release pellets population (XR1), and a

second extended release pellets population (XR2). Detailed analysis of the reference

product patents was done and out-of-scope strategy was finalized. Reference product’s

patent details are mentioned below;

Table 26: Orange book patent status of the Reference product

3.5.2 CHOICE OF EXCIPIENTS

The ideal choice of any generic equivalent is to use excipients similar to reference

product. This minimizes the risk of stability and increases the chance of matching in-vitro

and in-vivo profile of the drug substance. The innovator list of ingredients is available in

the product pack outsert. The initial ingredients for the formulation were chosen from the

commonly used excipients and the preference was given to the excipients used in the

reference product manufactured by Supernus Pharmaceuticals Inc. Excipients similar to

reference product were Sugar Spheres, Hypromellose, Mannitol, Docusate Sodium,

Sodium Benzoate, Polyethylene Glycol, Polyvinyl Alcohol, Titanium Dioxide, Talc, The

Appl No Prod No Patent No Patent Expiration

Drug Substance Claim

Drug Product Claim

N201635 001 8298576 Mar 18, 2029 ---- Y

N201635 001 8298580 Nov 16, 2027 ---- Y

N201635 001 8663683 Nov 16, 2027 ---- Y



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capsule shells contain gelatin, Titanium Dioxide, and Colorants. Apart from that, other

excipients also tried to match the in-vitro dissolution profile with Reference product.

Table 27: The preliminary list of excipients selected and their function Sr.No. Drug/Excipients/Chemicals Characteristics Manufacturer/

Supplier 1. Topiramate API Hetero Drugs Ltd. India 2. Sugar spheres Core pellets -MB sugars &

pharmaceutical, India -Pharm-a-spheres, Germany

3. Hypromellose 1 Binder/pore former Dow chemical, USA 4. Hypromellose 2 Binder/pore former Dow chemical, USA 5. Polyvinylpyrollidone Binder BASF 6. Mannitol Carrier Signet, India 7. Docusate sodium Solubilizer Techno drugs &

Intermediates, India 8. Sodium benzoate Preservative Avantor Performance

materials, India 9. Talc Anti-tacking agent Rio Tinto Minerals 10. Simethicone emulsion 30% Anti-foaming agent Rio-care 11. Ethyl cellulose ER polymer Colorcon 12. Eudragit ER polymer Evonik 13. Cellulose acetate ER Polymer Eastman 14. ER-3 ER polymer 3 Manufacturer-1 15. ER-4 ER Polymer 4 Manufacturer-2 16. Polyethylene glycol Pore former SD fine chem, India 17. PF-3 Pore former 3 Manufacturer-3 18. Triethyl citrate Plasticizer Merck, Germany 19. Dibutyl sebasate Plasticizer Sigma Aldrich 20. Opadry AMB Moisture barrier coat Colorcon, India 21. Opadry 200 Moisture barrier coat Colorcon, India 22. Opadry II white Moisture barrier coat Colorcon, India 23. Gelatin capsules Carrier for pellets Associated capsules 24. Purified water Solvent MilliQ purifier 25. Isopropyl alcohol Solvent S.D. Fine chem, India 26. Dichloromethane Solvent S.D. Fine chem, India 27. Acetone Solvent S.D. Fine chem, India

All the excipients used are of USP grade wherever applicable, manufactured by standard

sources with DMF numbers where ever applicable. For the developmental batches some



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of the excipients apart from the reference product were used to check the feasibility of the

alternate formula composition with similar release profile.

3.5.3 CORE PELLETS TYPE AND SIZE SELECTION

Various types of core pellets that can be used for drug layering using fluidized bed

processor are described in literature and are available commercially. These include

microcrystalline cellulose (MCC) spheres, sugar spheres, mannitol spheres, isomalt

spheres etc. Sugar spheres were selected based on patent analysis, RLD labeling and

drug-excipient compatibility study. Initially, development was started with #25/30 ASTM

mesh sugar spheres (Particle size: 600 to 710 µm), weight variation of finished product in

capsules was more with #25/30 ASTM mesh sugar shperes. Hence, small sized #40/60

ASTM mesh sugar spheres (Particle size: 250 to 425 µm) & #30/35 ASTM mesh sugar

spheres (Particle size: 500 to 600 µm) were evaluated to reduce the weight variation

during capsule filling. Sugar spheres were evaluated and found to comply with USP

requirements.

3.5.4 SEAL COAT ON CORE PELLETS OPTIMIZATION

Seal coat on core pellets was necessary to make the surface of core pellets smooth for

drug layering and to reduce the friability of core sugar pellets which leads to

improvement in the drug loading efficiency. Initially 3% weight gain was targeted

however at this level weight of the pellets was found to reduce due to surface erosion on

fluidization and it can be attributed to the incomplete coating of the core sugar spheres.

So it was decided to use sugar spheres coated to 5% w/w weight gain. Hypromellose was

used for seal coating without / with some other excipients as per reference product’s

literature information. Non-aqueous and aqueous solvent systems and different

concentration of solid dispersion were evaluated to achieve smooth manufacturing

process and good seal coating efficiency.



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Table 28: Formula for seal coating optimization

Product: Topiramate ER Capsule 200mg(API Particle size 10 micron) Batch No: 54 55 61 62 63 64 67 71

Sr. No. Ingredients Source Mg / Capsule

Seal coat (% w/w Dispersion) 10% 10% 10% 15% 10% 10% 15% 15%

1 Suigar spheres

25/30 Werner 100.0 100.0 100.0 100.0 100 100.0 100 ----

Suigar spheres

30/35 Werner ---- ---- ---- ---- ---- ---- ---- 100

2 Methocel E6LV Colorcon 3.0 ---- ---- ---- ---- ---- ---- ---- Methocel E5LV Colorcon ---- 3.0 3.0 4.0 2.5 2.5 2.5 2.5 Mannitol Signet ---- ---- ---- 0.5 1.63 1.63 1.63 1.63 Purified Talc Rio Tinto ---- ---- ---- 0.5 0.87 0.87 0.87 0.87

3 IPA (50%) S.D. Fine chem,

India 13.5 13.5 ---- ---- ---- ---- ---- ----

4 MDC (50%) S.D. Fine chem,

India 13.5 13.5 ---- ---- ---- ---- ---- ----

Purified Water In-House ---- ---- 27.0 28.3 45 45 28.3 28.3 Total 103.0 103.0 103.0 105.0 105.0 105.0 105.0 105.0

Table 29: Process Parameters for Seal coating on core sugar spheres at Bench-scale

(Batch size: 4000 capsules)

Sr. No. Before spraying Observation During Spraying Observation 1 Temperature (ºC) 25-30 Inlet temperature (ºC) 45 - 55 2 Related Humidity 4 - 10% Exhaust Temp. (ºC) 34 - 37 3 Process Type Wurster Product Temp. (ºC) 34 - 44 4 Air Distribution base plate C Blower drive (%) 30 - 40 5 Filter shaking Asynchronous Air flow (CFM/m/s) 35 - 40 6 Filter bag Cotton Spray rate (gm/min) 2 - 5 7 Tube Diameter 3.0 mm Spray RPM 3 - 15 8 Nozzle size 0.8 mm Atomization Pressure 1 - 1.1

3.5.5 DRUG LAYERING OPTIMIZATION

Initially, drug loading was done directly on the core pellets but later to improve the

loading efficiency, seal coated pellets with broad particle size distribution were selected

for drug layering. Various trials were planned and executed for optimization of drug

layering. Drug layering process optimization was most critical part of this whole

development as the drug crystals were sharded off from the surface of the core pellets due



123

to its crystalline nature. During this work, various strategies were conducted to improve

the drug loading on the core pellets. taking into account the following approaches:

• Selection of solvent system with different solid dispersion

• Effect of colloid milling

• Effect of plasticizer

• Selection of binder

• Effect of seal coating

• Effect of binder with colloid milled API

• Selection of solvent ratio with colloid milled API

• Selection of core pellets size with micronized API and non-aqueous solvent

system

• Effect of binder concentration with revised composition (As Reference product’s

excipients)

• Effect of solid dispersion with revised composition

• Effect of Mannitol concentration

• Effect of binder grade with revised composition

• Effect of core pellets size on drug loading with aqueous solvent system

• Effect of sodium benzoate and fumaric acid

• Effect of sodium benzoate and talc concentration

• Effect of other excipients with API and seal coated pellets ratio

3.5.5.1 Selection of solvent system with different solid dispersion

As Topiramate API belongs to BCS class II, solvent systems were selected based on drug

solubility in aqueous and non-aqueous solvents. The solubility profile was found to be as

shown in table 30. Procedure for the determination of solubility profile: accurately

weighed drug was taken in glass beaker. Measured quantity of solvent was added into the

beaker with intermittent shacking till clear solution is obtained.



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Table 30: Solubility profile of Topiramate in different solvents

Solvent Drug X: 3.00gm Boling point Observation IPA 15ml 82.5 Not completely dissolved

Water 15ml 100 Not completely dissolved Acetone 3ml 56

Completely dissolved Ethanol 10ml 78.37 MDC 13.5ml 39.6

Methanol 5ml 64.7

On the basis of solubility data, various feasibility trials using non-aqueous,

hydro-alcoholic and aqueous solvents were designed as follows.

Topiramate with API particle size D90-50 micron was selected for drug layering on sugar spheres 25/30. Table 31: Formula composition of Batch No. 001, 003, 005, 007, 007A, 007B & 007C

Sr. No

Batch No 001 003 005 007 007A 007B 007C

1 Ingredient Mg/cap 2 Sugar spheres 25/30 140 140 140 140 140 140 140 3 Topiramate 35 35 35 35 35 35 35 4 Methocel E15LV 7 NA 7 7 7 7 7 5 Kollidon K90 7 NA 7 7 7 7 6 Kollidon K30 3.5 NA 7 Simethicone 30% 0.13 0.3 0.3 0.3 0.3 0.3 8 Talc 2 2.1 3.5 NA 9 Talc UM NA 3.5 3.5 3.5 3.5 10 P.Water (%) 95 50 70 90 85 85 100 11 IPA (%) 5 50 15 10 15 15 NA 12 Acetone NA 50 15 NA 13 Dispersion % 18% 20% 15 20 20 15 15 14 Yield % 70 84 86 87.3 50 68 82.5

Observation and conclusion:

Drug solution prepared with the concentration of 20% of Hypromellose and

Polyvinylpyrrolidone. Dispersion was in the range from 15 to 20% with different

percentage of IPA, Acetone and Water but the process was not satisfactory due to sticky

tendency of binder solution doublets occurrence expected. Also because of particle size

of API gun chock was frequent therefore to solubilise API different solvent ratio was

selected (Water, IPA & Acetone).



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To overcome the problem API solution was colloid milled for 30 min and layered on core

pellets process and coating yield was satisfactory.

3.5.5.2 Effect of colloid milling

With observation of coating yield in B. No. 007C moving further coating solution

preparation optimization and coating yield to be increased during drug layering on sugar

spheres 25/30.

Table 32: Formula composition of Batch No. 007D & 008 Sr. No Batch No 007D 008

Ingredient 1. Sugar spheres 25/30 140 140 2. Topiramate 35 35 3. Methocel E15LV 7 7 4. Kollidon K90 7 7 5. Simethicone 30% 0.3 0.3 6. Talc UM 3.5 3.5

TEC NA P.Water (%) Qs Dispersion 15% 15% Yield 90.7% 86.8%

Procedure for preparing drug solution

Step 1 Disperse purified talc in required quantity of water then disperse drug to the same

solution. To avoid foam add Simethicone 30% emulsion. Step 2 In other part of P. Water

add Hypromellose and K90 under mechanical stirrer, stir well till it get completely

dissolved. Step 3 Pass step 1 solution to colloid mill and mill for 30 min to form a

uniform dispersion. Step 4 Discharge milled solution to Step 2 stir well to form uniform

suspension.

Observation and Conclusion:

- Colloid milled suspension when layered on core pellets coating yield was

satisfactory

- Drug layering process was satisfactory but the spray rate was maximum 3gm/min

sprayed if exceeded doublets formation observed.

- Nearly 15% overages required to have 100% coating yield

- Process and binder concentration to be modified for satisfactory yield.



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3.5.5.3 Effect of plasticizer

Colloid milled drug solution on drug layering yield and process was much better to other

different solvent ratio. As per literature search if plasticizer added to the drug layering

solution amount over ages will be reduced for complete 100% yield.

Table 33: Formula composition of Batch No. 030, 031 & 032 Batch No 030 031 032

Sr. No Ingredient Mg/cap 1 Sugar spheres 25/30 140 140 140 2 Topiramate 140 140 140 3 Methocel E15LV 28 28 NA 4 Kollidon K90 28 28 NA 5 Kollidon K30 NA 70 6 Simethicone 30% 2.8 2.8 2.8 7 Talc UM 7 7 7 8 TEC 10.3 20 10 9 P.Water QS 10 Dispersion 17.5 17.5 26.88 11 Yield 82.6 73.73 78.0


Triethyl citrate is water soluble plasticizer used in minimum to maximum concentration

as per IIG limit but the coating yield was under 90%. Hence it was understood plasticizer

doesn’t improve the coating yield.

With binder hypromellose and K90 spray rate was minimum there by process was slow

also sticking tendency relatively high. In proposed trial binder selection and

concentration to be selected for the satisfactory process and coating yield.

3.5.5.4 Selection of binder

With high viscosity polymer process and yield was not satisfactory to reduce doublet

formation and sticky nature of drug solution Povidone K30 was considered in different

concentration. Povidone K30 selection was based on Janssen Cilag Topamax sprinkle

capsule.

Table 34: Formula composition of Batch No. 032A, 031, 032, 032A & 033

Batch No 032A 031 032 032A 033 Sr. No Ingredient

1 Sugar spheres 25/30 140 140 140 140 140



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2 Topiramate 140 140 140 140 140 3 Methocel E15LV 28 28 NA 4 Kollidon K90 28 28 NA 5 Kollidon K30 NA 70 105 140 6 Simethicone 30% 2.8 2.8 2.8 2.8 2.8 7 Talc UM 7 7 7 7 7 8 TEC 10.3 20 10 10 10 9 P.Water (%) Qs 10 Dispersion 17.5 17.5 26.88 26.88 27.0 11 Yield 82.6 73.73 78.0 82.72 78.5


- With the high viscosity polymer (Hypromellose and K90) spray rate was minimum

and duration of coating was not satisfactory.

- With Povidone K30 if spray rate increased above 4gm/min there is no observation of

doublets or sticking tendency of pellets in bowl.

- Coating yield was under 90% even dispersion was increased.

- With 75% of binder concentration coating yield was satisfactory

3.5.5.5 Effect of seal coating

With binder drug concentration (1:1) process and coating yield was satisfactory so we

propose to seal coat the core pellets. Seal coating makes surface of sugar spheres smooth

and the coating yield can be increased. Also during fluidization of core pellet during pre

warming dust generation observed this is due to loss in core sugar spheres to avoid this

loss seal coat require.

Table 35: Formula composition of Batch No. 033 & 034 Sr. No Batch No 033 034

Ingredient Mg/cap Seal coating 1 Sugar spheres 25/30 140 140 2 Pharmacoat 603 ---- 4.2 3 IPA ---- Q.S. 4 MDC ---- Q.S. Drug coat 5 Seal coated pellet ---- 144.2 6 Sugar sphere 25/30 140 ---- 7 Topiramate 140 140



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8 Kollidon K30 140 140 9 Simethicone 30% 2.8 2.8 10 Talc UM 7 7 11 TEC 10 10 12 P.Water Qs 13 Total 439.8 444 14 Dispersion % 27 33 15 Yield % 78.5 87.6


After seal coating the core sugar spheres coating weight gain considerably increased.

Therefore with the above data it was concluded core sugar spheres to be seal coated.

3.5.5.6 Effect of binder with colloid milled API

With K30 additional polymer we proposed to use to increase the coating yield also

process should be satisfactory.

Table 36: Formula composition of Batch No. 035, 036, 037, 038, 039 & 040 Batch No 035 036 037 038 039 040

Sr. No Ingredient Mg/cap Seal coating 1 Sugar spheres 25/30 140 140 140 140 140 140 2 Pharmacoat 603 4.2 4.2 4.2 4.2 4.2 3 Kollidon K30 q.s. 4.2 4 IPA q.s. 5 MDC q.s. Drug coat 6 Seal coated pellet 144.2 144.2 144.2 144.2 144.2 144.2 7 Topiramate 140 140 140 140 140 140 8 Kollidon K30 126 126 126 175 140 140 9 Methocel E15LV 14 NA 10 Klucel LF NA 14 NA 11 Kollidon K90 NA 14 NA 12 Simethicone 30% 2.8 2.8 2.8 2.8 2.8 2.8 13 P. Talc 7 7 7 7 7 7 14 TEC 10 10 10 10 10 10 15 P.Water Qs 16 Total 444 444 444 479 444 444 Dispersion 33 27 33 33 37.5 37.5

Yield 84 84 79 86.7 82 89



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Observation and Conclusion

With the addition of polymer to K30 doesn’t have impact on increasing coating yield. It

was observed during spray of drug solution on sugar spheres sticking tendency and the

spray rate was reduced due to this process time increased. Therefore it was concluded

apart from K30 any polymer included in drug layering system yield, duration of layering

and process was not satisfactory.

3.5.5.7 Selection of solvent ratio with colloid milled API (50 micron)

Increase in binder concentration, addition of additional polymer and seal coating of core

sugar spheres have not much impact on coating yield. So it was decided to add isopropyl

alcohol in different proportion to water to increase the coating yield.

Table 37: Formula composition of Batch No. 042, 043, 044, 045 & 047

Sr. No Batch No 042 043 044 045 047 Ingredient Mg/cap

Seal coating 1 Sugar spheres 25/30 140 140 140 140 140 2 Kollidon K30 4.2 3 IPA Qs 4 MDC Qs Drug coat 5 Seal coated pellet 144.2 144.2 144.2 144.2 144.2 6 Topiramate 140 140 140 140 140 7 Kollidon K30 140 126 70 105 140 8 Methocel E6LV NA 9 Simethicone 30% 2.8 2.8 2.8 2.8 2.8 10 P. Talc 7 7 7 7 7 11 TEC 10 10 10 10 10 12 P.Water (%) 90 70 70 50 70 13 IPA 10 30 30 50 30 14 Total 444 444 374 409 444 15 Dispersion % 33 32 28.2 24.5 37.5 16 Yield % 80.7 93.1 67.53 93.56 83.67


Topiramate when added to isopropyl alcohol get partially soluble so sticking tendency of

solution increased. For higher concentration of binder isopropyl alcohol 10% added for

lower concentration of binder isopropyl alcohol concentration was increased. It was



130

found with 90% of binder concentration and isopropyl alcohol 30% concentration having

a satisfactory yield. But the process was not satisfactory due to slow spray rate.

3.5.5.8 Selection of core pellets size with micronized API and non-aqueous solvent

system

Finally coating yield was 90% observed in B. No. 043 & 045 to increase further coating

yield different the pellet size fraction used.

Table 38: Formula composition of Batch No. 048 & 049

Batch No 048 049 Sr. No Ingredient Seal coating 1 Sugar spheres 40/60 140 2 Sugar spheres 25/30 140 3 Kollidon K30 4.2 4 IPA Qs 5 MDC Qs Drug coat 6 Seal coated pellet 144.2 144.2 7 Topiramate 140 140 8 Kollidon K30 70 70 9 Simethicone 30% 2.8 2.8 10 Talc UM 7 7 11 TEC 10 10 12 P.Water (%) 70 70 13 IPA 30 30 14 Total 371.2 371.2 15 Dispersion 15 15 16 Yield 87.5 80.8

Observation and Conclusion

With the sugar spheres 25/30 and 40/60 coating yield was not more than 90%. With the

size fraction of 40/60 process was not satisfactory doublets formation observed. Hence

finally it was concluded if surface area increased by reducing the size of sugar pellets

coating yield was not satisfactory.



131

3.5.5.9 Effect of Binder concentration with revised composition (As Reference

product’s excipients)

Polymer concentration to be evaluated with micronized particle size of API

Hypromellose with different concentration selected keeping mannitol in same

concentration to determine the coating yield with micronized API.

Table 39: Formula composition of Batch No. 050A, 054, 054B & 055

Sr. No Batch No 050A 054 054B 55

Ingredients Mg/cap 1 Seal coated pellets 25/30 103 103 103 103

2 Topiramate 140 140 140 140 3 Methocel E15 LV 35 14 21 28 4 Mannitol 14 14 14 21 5 Purified Talc 7 7 7 9 6 Triethyl citrate 10 NA 7 Water Qs 8 Total 309 278 285 301 9 Dispersion % 15 15 25 15 10 Yield % 73 88.7 93 91


With particle size of less than 10 micron API having satisfactory coating yield when

compared to all the above trials with the API particle size of less than 50 micron. Finally

it clearly indicates particle size of API plays a critical role in drug layering system with

higher particle size in different concentration of polymer, different grade and viscosity of

polymer, different solvent ratio with different dispersion coating yield was not increased.

With API particle size less than 10 microns with less concentration of polymer coating

yield was more than 90% achieved. The above formula arrived based on innovator

excipients used in Trokendi XR by Supernus. With nearly 15% of Hypromellose and 10%

of mannitol to the API achieved a desired coating yield.



132

3.5.5.10 Effect of solid dispersion with revised composition Table 40: Formula composition of Batch No. 054B, 058 & 060

Sr. No Batch No 054B 058 060 Ingredients Mg/cap

1 Seal coated pellets 25/30 103 103 103

2 Topiramate 140 140 140

3 Methocel E15 LV 21 21 21 4 Mannitol 14 14 14 5 Purified Talc 7 7 7 7 Water Qs 8 Total 285 285 285 9 Dispersion % 25 15 20 10 Nozzle 1.2 mm 0.8 mm 1.2 mm 11 Yield % 73 88.7 93


With the polymer concentration was nearly 15% to Topiramate API coating yield was

more than 90% to reduce the duration of drug layering and to increase coating yield to

satisfactory level different dispersion was selected. With dispersion 25% undesirable

foam generation observed so 25% dispersion in scale up it is difficult to control. The

effect of nozzle also studied because with 0.8mm nozzle chocking observed so 1.2 mm

nozzle preferred for drug layering performed and satisfactory coating yield and process

observed. So it was concluded with 1.2 mm nozzle and 20%w/w dispersion having

satisfactory coating yield.

3.5.5.11 Effect of mannitol concentration

Concentration of polymer was selected based on coating yield, the importance of mannitol

to be established in drug layering composition. Hypromellose concentration was

maintained in same concentration only the mannitol concentration was varying in below

mentioned Table 41;

Table 41: Formula composition of Batch No.056, 057, 058 & 059

Sr. No Batch No 56 57 58 59

Ingredients Mg/cap



133

1 Seal coated pellets 25/30 103 103 103 103

2 Topiramate 140 140 140 140

3 Methocel E15 LV 21 21 21 21 4 Kollidon K30 NA NA NA 14 5 Mannitol NA 21 14 7 6 Purified Talc 7 7 7 7 8 Water Qs

9 Total 271 309 278 285 10 Dispersion % 25 25 15 25 11 Yield % 92 90.23 90.40 90.10


With mannitol drug layering process was satisfactory and no doublets formation was

observed. Without mannitol marginal doublets observed and spray rate was less due to

this duration of coating increased. With different concentration of mannitol coating yield

was observed to be more than 90%. Therefore optimum concentration of mannitol was

selected for further development of Topiramate ER Capsule.

3.5.5.12 Effect of binder grade with revised composition

Drug layering system was developed with aqueous system but seal coating with E5 LV in

non aqueous system considering stability both seal coating and drug layering should be in

same solvent system. Hence, excluding Topiramate in drug layering system, same

concentration of polymer, mannitol and anti tacking agent preferred for seal coating.

Table 42: Formula composition of Batch No. 060 & 062

Sr. No Batch No 60 62 Ingredients Mg/cap 1 Sugar spheres 25/30 100 100 2 Methocel E5LV 3 4 3 Mannitol NA 0.5 4 Talc NA 0.5 5 IPA Qs Na 6 MDC Qs Na 8 P.Water NA Qs Drug layering 9 Seal coated pellets 103 105 10 Topiramate 140 140



134

11 Methocel E15 LV 21 NA 12 Methocel E5 LV NA 21 13 Mannitol 14 14 14 Purified Talc 7 7 15 Water q.s. 16 Total 285 287 17 Dispersion % 25 25 18 Yield % 285 287


With Methocel E5 LV in seal coating having weight gain of 3% was not satisfactory

because in 3% weight gain lose of core pellets was observed during drying. Weight gain

of 3% coating doesn’t cover the core pellet uniformly so the loss observed. In B. No. 062

seal coating formula developed with the weight gain of 5% which covers uniformly the

core pellets which prevents the loss due to friction between the pellets while fluidizing

them. With Hypromellose 5cps and 15cps drug layering performed from the process point

of view both the polymer behaviour was same and drug spray maximum 5hm/min

sprayed no doublets observed also the weight gain more than 90%. Considering the

process and coating yield Hypromellose 5cps can be used for drug layering of Topiramate

ER Capsule.

3.5.5.13 Effect of core pellets size on drug loading with aqueous solvent system

Table 43: Formula composition of Batch No. 066 & 071 Sr.No Batch No 66 71

1 Core sugar spheres size #25/30 #30/35 2 Seal coated pellets 105 105 3 Topiramate 140 140 4 Methocel E5 LV 21 21 5 Mannitol 14 14 6 Purified Talc 7 7 7 Water (70%) 728 728 8 Dispersion 20% 20% 9 Yield % 100.83% 100.36% 10 Overages required 5% 5%



135

3.5.5.14 Effect of sodium benzoate and fumaric acid

Sodium benzoate and fumaric acid in the concentration of 58mg per capsules were

prepared for evaluation of drug loading efficiency as per formula composition in below

table 44.

Table 44: Formula composition of Batch No. 74A & 74B Sr.No Batch No 74A 74B

1 Batch size 2000 2000 2 Core sugar spheres size #30/35 #30/35 3 Seal coated pellets 105 105 4 Topiramate 140 140 5 Methocel E5 LV 21 21 6 Mannitol 14 14 7 Purified Talc 7 7 8 Fumaric acid 58 9 Sodium Benzoate 58 ---- 10 Water (100%) 720 720 11 Dispersion 25% 25% 12 Total seal coated pellets wt./capsule 345 345 13 Seal coated Pellet core weight/Batch 210 210 14 Practical solid load/Batch 480 414 15 Theoretical Solid loading/Batch 480 480 16 Yield % 100.00% 86.25% 17 Overages required 5% 5%

3.5.5.15 Effect of sodium benzoate and talc concentration

Sodium benzoate and Talc in various concentration were prepared for evaluation of drug

loading efficiency as per formula composition in below table 45.

Table 45: Formula composition of Batch No. 74A, 75 & 76 Sr.No Batch No 74A 75 76

1 Batch size 2000 2000 2500 2 Core sugar spheres size #30/35 #30/35 #30/35 3 Seal coated pellets 105 105 105 4 Topiramate 140 170 170 5 Methocel E5 LV 21 25.5 25.5 6 Mannitol 14 17 17 7 Purified Talc 7 8.5 17 8 Sodium Benzoate 58 29 5 9 Water (100%) 720 793.5 678 10 Dispersion 25% 25% 25% 11 Yield % 100% 98.81% 92.90%



136

12 Nozzle diameter 1.2 mm 0.8 mm 0.8 mm 13 Overages required 5% 35% 20% 14 Agglomerates (%) [Approx.] 40% 20% 10%

3.5.5.16 Effect of other excipients with API and Seal coated pellets ratio

Other excipient such as dosusate sodium as solubilizer and Sodium benzoate with

different ratio of seal coated pellets to topiramate in various concentration were prepared

for evaluation of drug loading efficiency and drug release as per formula composition in

below table 46.

Table 46: Formula composition of Batch No. 077 & 078 Sr.No Batch No 77 78

1 Batch size 2500 2500 2 Core sugar spheres size #30/35 #30/35 3 Seal coated pellets 105 170 4 Topiramate 170 170 5 Methocel E5 LV 25.5 25.5 6 Mannitol 17 17 7 Purified Talc 17 17 8 Docusate sodium 5.27 5.27 9 Sodium Benzoate ---- 0.023 10 Water (100%) 678 704.4 11 Dispersion 25% 25% 12 Yield % 100.27% 100.36% 13 Overages required 10% 6%

Table 47: Final optimized Process Parameters for Drug layering at Lab-scale (Batch size: 4000 capsules)

Sr. No. Before spraying Observation During Spraying Observation 1 Temperature (ºC) 25-30 Inlet temperature (ºC) 50-65 2 Related Humidity 5 - 10% Exhaust Temp. (ºC) 40-47 3 Process Type Wurster Product Temp. (ºC) 42-47

4 Air Distribution base

plate C Blower drive (%) 50-75

5 Filter shaking Asynchronous Air flow (CFM/m/s) 50-65 6 Filter bag Cotton Spray rate (gm/min) 4-20 7 Tube Diameter 3.0 mm Spray RPM 3-20 8 Nozzle size 1.2 mm Atomization Pressure 1-1.2



137

3.5.6 MODIFIED RELEASE COATING OPTIMIZATION

Along with optimization of drug layering to obtain desired drug loading percentage yield

and smooth surface of pellets, these pellets were subsequently coated with various

extended release polymer coating to obtain desired release profile comparable with that

of reference product. Various trials were executed using Ethyl cellulose, Eudragit RS30D

and Cellulose acetate as extended release (ER) polymer along with or without delayed

release (DR) polymer. The main of designing the modified release coating strategy was

based on the similar dissolution pattern as that of Reference product. Majorly, Two design

strategy were utilized and evaluated the drug release pattern, one of them was drug

layering on the core pellets in three different layer along with ER and DR polymer

coating in between three drug layer (Core pellets/drug layering/ER coating/drug

layering/DR coating/drug layering/ Top coat) and other one was drug layering on the core

pellets in two different layer along with ER polymer coating in between two drug layer

(Core pellets/drug layering/ER coating/drug layering/ Top coat). Immediate release drug

layer portion was coated on ER coated or DR coated pellets, to be considered as loading

dose, which shall be released the drug immediately upon ingestion of the dosage form, so

that, release profile of the optimum batch can be compared with reference product.

Initially, Modified release coating design was tried to establish the dissolution pattern as

that of Reference product. Top immediate release drug layer portion was protected with

moisture barrier coat at the top and pellets were filled into capsules and subjected to

dissolution study. Initially, water as the dissolution media was tried, latter pH 6.8

phosphate buffer and multi-media with pH 2.1 HCL media followed by pH 6.8 phosphate

buffer were evaluated as dissolution media. Modified release coating strategy was

optimized to get the dissolution pattern as that of the reference product, final formulation

composition was optimized by using statistical formula optimization techniques with the

help of “Design Expert” Software ver. 8.0.7.1 Once the Reference product launched in

USA market, innovator disclosed the dissolution condition in pH 7.5 Phosphate buffer as

Drug release media for routine quality control testing of the final formulation and

stability samples. Various approaches were tried to get the in-vitro drug release pattern

similar to reference product;



138

3.5.6.1 Modified release coating with Ethyl cellulose polymer as ER coating

3.5.6.2 Modified release coating with Eudragit RS30D polymer as ER coating

3.5.6.3 Modified release coating with Cellulose acetate polymer as ER coating

3.5.6.3.1 Modified release coating with ER coating (Two drug layers)

3.5.6.3.2 Modified release coating with ER coating and DR coating (Three drug

layers)

3.5.6.3.3 Modified release coating with novel ER coating (Two drug layers)

3.5.6.1 Modified release coating with Ethyl cellulose polymer as ER coating

Ethyl cellulose with particular concentrations of pore former was used for extended

release (ER) coating. Trial was designed to check the dissolution pattern with Ethyl

cellulose based ER coating system with 30% pore former and 20% weight gain of ER

coat. Summary of this design was 70% of 200mg of Topiramate API was loaded on seal

coated pellets, followed by 20% w/w ER coating with ethyl cellulose and hypromellose

in the ratio of 70:30, followed by 15% of 200mg API layering, followed by 12.30% w/w

of Delayed release (DR) coating and finally, top coat with 15% of 200mg API layering as

immediate release portion at the surface of the coated pellets. Detailed composition of

each layer of the pellets with ethyl cellulose strategy is mentioned below;

Table 48: Formula composition with ethyl cellulose polymer as ER coating material

(B# 62A)

Batch No: 62A Sr. No. Ingredients mg/unit

Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100.0 2 Methocel E5LV (80%) 4.0 3 Mannitol (10%) 0.5 4 Purified Talc (10%) 0.5 5 P.Water (22.73 % w/w Dispersion) 17.0 Total 105.0 Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105.0 7 Topiramate (70% of 200mg) 140.0 8 Methocel E5LV (50%) (15% of API) 21.0



139

9 Mannitol (33.33%) (10% of API) 14.0 10 Purified Talc (16.66%) (5% of API) 7.0 11 P.Water (20 % w/w Dispersion) 728.0 Total 287.0 Seal coating 3% w/w wt. gain

12 Drug coated pellets 287.0 13 Methocel E5LV (50%) 4.3 14 Mannitol (32.56%) 2.8 15 Purified Talc (17.44%) 1.5 16 P.Water (22.73 % w/w Dispersion) 29.2 Total 295.6 ER coat 20% w/w Polymer

17 Drug layerd seal coat pellet 295.6 18 Surelease E-7-19040 (70%) 41.38 19 Methocel E5 LV (30%) 17.74 20 P.Water (15 % w/w Dispersion) 335.013 Total 354.72 Drug layering 11% w/w wt. gain

21 ER coated pellet (EC 70%) 354.7 22 Topiramate (15% of 200 mg) 30.0 23 Methocel E5LV (50%) (15% of API) 4.5 24 Mannitol (33.33%) (10% of API) 3.0 25 Purified Talc (16.67%) (5% of API) 1.5 26 P.Water (20 % w/w Dispersion) 156.0 Total 393.7 DR coat 12.3% w/w (10.24 % w/w Polymer)

27 ER coated pellet (EC) 393.7 28 Eudragit S 100(83.22%) 40.3 29 Talc (8.5%) (10% of Polymer) 4.1 30 TEC (8.5%) (10% of Polymer) 4.1 31 Acetone (8.36 % w/w Dispersion) 531.0 Total 442.1 Drug layering 8.82% w/w wt. gain

32 DR coated pellet 442.1 33 Topiramate (15% of 200 mg) 30.0 34 Methocel E5LV (50%) (15% of API) 4.5 35 Mannitol (33.33%) (10% of API) 3.0 36 Purified Talc (16.67%) (5% of API) 1.5 37 P.Water (20 % w/w Dispersion) 156.0 Total 481.1



140

Table 49: Manufacturing process parameter for Trial batch #62A

Seal coating parameter (Lab-scale) at FD

Sugar spheres: #25/30 mesh, Seal coated sugar spheres: #25/30 Start Load 350 g End

Load 371 g

Spray Nozzle size: 0.8 mm

Filter Bag: Nylon Base plate: C Tube

Dia: 3 mm

Time (min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition

Height

Set Act Set Act Act Act % Act CFM rpm g Act Act % mm

0 45 38 40 30 30 30 38 4 1 1 11 20 5 45 45 40 34 40 33 41 5 1.5 1 6 20 10 49 49 40 37 43 33 40 5 1.5 1 6 20 30 50 50 40 38 41 35 41 10 3 1.1 6 20 60 54 53 40 39 42 37 45 17 6 1.1 5 20 75 58 58 40 40 43 37 42 20 7.1 1.2 4 20

Drying for 15 min at 45ºC Temperature

Drug Layering parameter (Lab-scale) at FD Seal coated sugar spheres: #25/30

Drug layered pellets: #18/30 Start Load 309 g End

Load 855 g


Filter Bag: Cotton Base plate: C Tube

Dia: 4 mm

Time (min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height


0 45 42 45 34 34 35 42 4 2 1.1 9 20 30 47 47 40 34 36 35 40 8 4 1.1 9 20 60 51 49 45 36 36 36 40 11 9 1.1 7 20 90 51 51 45 35 36 36 37 12 10 1.1 6 20 120 52 50 45 35 37 39 40 15 10 1.1 5 20 150 52 52 45 34 36 39 40 15 10 1.1 5 20 180 52 52 45 34 36 39 41 15 10 1.1 5 20 210 57 54 45 34 36 39 41 17 11 1.1 5 20 240 57 57 45 35 36 39 40 19 12 1.2 4 20 270 58 57 45 34 36 39 38 19 12 1.2 4 20


Effect of temperature and stress stability condition on dissolution profile of the ethyl

cellulose coated pellets was evaluated to chose the suitable extended release polymer.



141

3.5.6.2 Modified release coating with Eudragit RS30D polymer

Eudragit RS30D as another extended release polymer was evaluated without any pore

former for extended release (ER) coating, followed by drug layering and delayer release

(DR) coating with and without pore former were evaluated. Trial was designed to check the

dissolution pattern with Eudragit RS30D based ER coating system without any pore former

along with delayed release (DR) coating with or without pore former. Summary of this

design was 70% of 200mg of Topiramate API was loaded on seal coated pellets, followed

by 20% w/w ER coating with Eudragit RS30D, followed by 15% of 200mg API layering,

followed by 15% w/w of Delayed release (DR) coating without and with pore former.

Finally, top coat with 15% of 200mg API layering as immediate release portion at the

surface of the coated pellets. Detailed composition of each layer of the pellets with ethyl

cellulose strategy is mentioned below;

Table 50: Formula composition with Eudragit RS30D polymer as ER coating material Batch No: 64 Batch No: 65

Sr. No. Ingredients mg/unit Sr. No. Ingredients mg/unit

Seal coat 5% w/w wt. gain Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100 1 Suigar spheres 25/30 100 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (50%) 2.5 3 Mannitol (32%) 1.63 3 Mannitol (32%) 1.63 4 Purified Talc (18%) 0.87 4 Purified Talc (18%) 0.87 5 P.Water (10% w/w Dispersion) 45 5 P.Water (10% w/w Dispersion) 45 Total 105.0 Total 105.0 Drug layering 173.33% w/w wt. gain Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 7 Topiramate (70% of 200mg) 140

8 Methocel E5LV (50%) (15% of API)

21 8 Methocel E5LV (50%) (15% of API)

21

9 Mannitol (33.33%) (10% of API)

14 9 Mannitol (33.33%) (10% of API) 14

10 Purified Talc (16.66%) (5% of API)

7 10 Purified Talc (16.66%) (5% of API)

7

11 P.Water (20 % w/w Dispersion)

728 11 P.Water (20 % w/w Dispersion) 728

Total 287 Total 287 Seal coating 3% w/w wt. gain Seal coating 3% w/w wt. gain

12 Drug coated pellets 287 1 Drug coated pellets 287 13 Methocel E5LV (50%) 4.3 2 Methocel E5LV (50%) 4.3 14 Mannitol (32.56%) 2.8 3 Mannitol (32.56%) 2.8



142

15 Purified Talc (17.44%) 1.5 4 Purified Talc (17.44%) 1.5


48.7 5 P.Water (15 % w/w Dispersion) 48.7

17 Total 295.6 6 Total 295.6

ER coat 20% w/w (15.8% w/w Polymer)


13 Drug layerd seal coated pellet 295.6 13 Drug layerd seal coat pellet 295.6

14 Eudragit RS 30D (100% of Polymer)

46.7 14 Eudragit RS 30D (100% of Polymer)

46.7

15 Triethyl citrate (7.6% of Polymer)

3.55 15 Triethyl citrate (7.6% of Polymer) 3.55

16 Talc (19% of Polymer) 8.87 16 Talc (19% of Polymer) 8.87 17 Water 226.06 17 Water 226.06 19 Total (20.73% dispersion) 354.72 19 Total (20.73% dispersion) 354.72 Drug layering 11% w/w wt. gain Drug layering 11% w/w wt. gain

20 ER coated pellet 354.72 20 ER coated pellet 354.72 21 Topiramate (15% of 200 mg) 30 21 Topiramate (15% of 200 mg) 30


4.5 22 Methocel E5LV (50%) (15% of API)

4.5

23 Mannitol (33.33%) (10% of API)

3 23 Mannitol (33.33%) (10% of API) 3


1.5 24 Purified Talc (16.67%) (5% of API)

1.5



27 Total 393.72 27 Total 393.72

DR coat 14.43% w/w wt. gain (11.55% w/w polymer)

DR coat 15% w/w wt. gain (12% w/w polymer)

28 ER coated pellet (RS 30D) 393.72 28 ER coated pellet (RSPO) 393.72

29 Eudragit S 100 45.47 29 Eudragit S 100 (87.52% of Total polymer)

41.36

30 Talc 5.68 30 Methocel E5LV (12.48% of Total polymer)

5.9

31 TEC 5.68 31 Talc (12.48% of Total polymer) 5.9

32 Acetone (10 % w/w Dispersion)

511.5 32 TEC (12.48% of Total polymer) 5.9

33 Total 450.55 33 Acetone (88.66% of Total solvent)

453.5

Drug layering 8.95% w/w wt. gain 34 Water (11.34% of Total solvent) 58 34 DR coated pellets 435.75 35 Total (10.35% w/w dispersion) 452.78 35 Topiramate (15% of 200 mg) 30 Drug layering 8.6% w/w wt. gain


4.5 36 DR coated pellets 452.78

37 Mannitol (33.33%) (10% of API)

3 37 Topiramate (15% of 200 mg) 30



4.5

39 P.Water (20 % w/w 156 39 Mannitol (33.33%) (10% of 3



143

Dispersion) API)

40 Total 474.75 40 Purified Talc (16.67%) (5% of API)

1.5

41 P.Water (20 % w/w Dispersion) 156 42 Total 491.78

Table 51: Manufacturing process parameter for Trial batch #64 & #65

Seal coating parameter (Lab-scale) at FD

Sugar spheres: #25/30 mesh, Seal coated sugar spheres: #25/30 Start Load 1000 g End

Load 1050 g



Dia: 4 mm

Time (min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust

Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height


0 45 38 40 30 30 30 38 4 1 1 11 25 5 45 45 40 34 40 33 41 5 1.5 1 6 25 10 49 49 40 37 43 33 40 5 1.5 1 6 25 30 50 50 40 38 41 35 41 10 3 1.1 6 25 60 54 53 40 39 42 37 45 17 6 1.1 5 25 75 58 58 40 40 43 37 42 20 7.1 1.2 4 25


Drug Layering parameter (Lab-scale) at FD Seal coated sugar spheres: #25/30

Drug layered pellets: #18/30 Start Load 493.5 g End

Load 1348.9 g



Dia: 3 mm

Time (H.

min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust

Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height


11.30 50 50 45 30 38 34 31 4 2 1 6 20 12.00 60 58 45 36 41 35 32 6 3 1 4 20 12.30 57 57 45 37 40 41 36 8 5 1 5 20 13.00 57 56 45 38 40 41 36 8 6 1 5 20 13.30 61 61 45 38 40 43 36 12 8 1 5 20 14.15 61 59 45 38 40 45 35 13 9 1 4 20 14.54 65 63 45 38 40 50 43 20 10 1.1 4 20 15.30 63 62 45 38 40 50 46 18 11 1.1 4 20 16.10 68 66 45 38 40 52 47 25 13 1.1 3 20



144

17.00 66 66 45 39 41 56 52 23 12 1.1 4 20 17.30 65 66 45 38 40 58 56 23 12 1.1 4 25 18.00 67 67 45 39 40 64 58 29 16 1.2 3 25 18.30 68 67 45 39 40 70 64 30 17 1.2 3 25 Drying for 20 min at 45ºC Temperature

ER coating parameter (Lab-scale) at FD

Drug layered pellets: #16/25 ER coated pellets: #16/25 Start Load 310.4 g

End Load 372.4 g

Spray Nozzle size: 0.8 mm Filter Bag: Cotton Base plate: C Tube

Dia: 3 mm

Time (Hr. min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust

Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height

Set Act Set Act Act Act % Act CFM rpm g Act Act % mm 15.10 32 33 40 28 28 50 48 1 1 0.9 19 15 15.20 32 32 40 28 28 52 49 2 2 0.9 18 15 15.50 34 35 40 27 28 55 52 5 3 1 15 15 16.00 37 37 40 27 27 58 53 8 5 1 13 15 16.25 38 38 40 27 27 59 54 10 6 1 13 15 Drying for 30 min at 35ºC to 45ºC Temperature

IR Drug Layering parameter (Lab-scale) at FD

ER Coated pellets: #16/25 IR+ER coated pellets: #16/25 Start Load 298.6

g End Load 366.2 g



Dia: 3 mm

Time (Hr. min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust

Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height

Set Act Set Act Act Act % Act CFM rpm g Act Act % mm 11.00 54 53 40 33 41 40 37 2 1 4 4 15 11.15 60 59 40 37 40 49 43 9 6 1 4 15 11.40 55 52 40 37 39 49 43 5 4 1 4 15 11.50 57 56 40 38 40 51 46 8 6 1 4 15 Drying for 15 min at 45ºC Temperature



145

DR coating parameter (Lab-scale) at FD

Drug layered pellets: #16/25 ER coated pellets: #16/25 Start Load 330 g End Load 379.5 g

Spray Nozzle size: 0.8 mm Filter Bag: Cotton Base plate: C Tube

Dia: 3 mm

Time (Hr. min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust

Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height

Set Act Set Act Act Act % Act CFM rpm g Act Act % mm 13.10 32 33 40 29 30 50 49 1 1 1 17 15 14.15 34 34 40 30 31 54 50 5 3 1 15 15 14.30 34 35 40 30 30 58 53 10 5 1 14 15 14.45 34 33 40 29 29 59 52 13 7 1 16 15 15.07 34 33 40 29 29 59 52 13 7 1 16 15 Drying for 15 min at 35ºC to 40ºC Temperature

IR Drug Layering parameter (Lab-scale) at FD

ER Coated pellets: #16/25 IR+ER coated pellets: #16/25 Start Load 349.9

g End Load 377.5 g



Dia: 3 mm

Time (Hr. min)

Inlet Temp. (ºC)

Exhaust Temp. (ºC)

Product/ Bed

Temp. (ºC)

% Exhaust

Flap open

Air volume

(CFM/m/s)

Spray Rate (g/min)

Atomization

RH Inlet

Partition Height

Set Act Set Act Act Act % Act CFM rpm g Act Act % mm 16.50 52 52 40 36 39 50 44 2 1 1 7 15 17.00 58 57 40 37 39 56 49 9 5 1 4 15 17.15 58 58 40 39 40 58 50 9 6 1 4 15 Drying for 15 min at 45ºC Temperature

3.5.6.3 Modified release coating with Cellulose acetate polymer

Cellulose acetate as another extended release polymer was evaluated with and without pore

former for extended release (ER) coating, followed by drug layering only or with delayer

release (DR) coating with and without pore former, followed by immediate release drug

layering portion at top were evaluated. Effect of storage temperature was evaluated with

cellulose acetate coated pellets. Various strategies were evaluated with cellulose acetate

based ER coated pellets to get similar kind of dissolution profile in multiple dissolution

condition. Mainly following four strategies were evaluated;



146

3.5.6.3.1 Modified release coating with ER coating (Two drug layers)

In this trial, 70% of 200mg of Topiramate API was loaded on seal coated pellets, followed

by 15% w/w ER coating with cellulose acetate alone and different concentration of

polyethylene glycol as pore former, followed by 30% of 200mg API layering to identify the

role of the pore former in ER coating layer with the help of the dissolution profile. In this

strategy, drug layering was done in two layers, first one was on the initial seal coated pellets

and next one was on the ER coated pellets. Detailed composition of each layer of the

pellets with ethyl cellulose strategy is mentioned below;

Table 52: Formula composition with Cellulose acetate polymer as ER coating material with/without pore former (B# 63D, 63A) Batch No: 63D Batch No: 63A

Sr. No. Ingredients

mg/unit

Sr. No. Ingredients

mg/unit

Seal coat 5% w/w wt. gain Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100 1 Suigar spheres 25/30 100 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 4 Purified Talc (18%) 0.9

5 P.Water (15% w/w Dispersion)

28 5 P.Water (15% w/w Dispersion) 28

Total 105.0 Total 105.0

Drug layering 173.33% w/w wt. gain


6 Seal coated pellets 105 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 7 Topiramate (70% of 200mg) 140



21

9 Pearlitol 25 (33.33%) (10% of API)

14 9 Pearlitol 25 (33.33%) (10% of API)

14



7



Total 287 Total 287 Seal coating 3% w/w wt. gain Seal coating 3% w/w wt. gain 1 Drug coated pellets 287 12 Drug coated pellets 287 2 Methocel E5LV (50%) 4.3 13 Methocel E5LV (50%) 4.3 3 Pearlitol 25 (32.56%) 2.8 14 Pearlitol 25 (32.56%) 2.8 4 Purified Talc (17.44%) 1.5 15 Purified Talc (17.44%) 1.5



147

5 P.Water (15% w/w dispersion)

48.7 16 P.Water (15% w/w dispersion) 48.7

6 Total 295.6 17 Total 295.6


ER coat 15% w/w (14.25 % w/w Polymer)

1 Drug layerd seal coat pellet 295.6 1 Drug layerd seal coat pellet 295.6

2 Cellulose acetate (398-10) (100% of Total polymer)

42.12 2 Cellulose acetate (398-10) (94.73% of Total polymer)

39.91

3 Triethyl citrate (5.27% of Total polymer)

2.22 3 PEG 4000 (5.27% of Total polymer)

2.22

4 Acetone (8% Dispersion) 510 4 Triethyl citrate (5.27% of Total polymer)

2.22

5 Total 339.94 5 P.Water (3.39% of Total solvent) 16.11


6 Acetone (96.61% of Total solvent)

459

6 ER coated pellet (CA) 339.91 7 Total (8.54% w/w Dispersion) 339.95 7 Topiramate (30% of 200mg) 60 Drug layering 22.95% w/w wt. gain


9 8 ER coated pellet (CA) 339.95

9 Pearlitol 25 (33.33%) (10% of API)

6 9 Topiramate (30% of 200mg) 60



9


312 11 Pearlitol 25 (33.33%) (10% of API)

6

12 Total 417.91 12 Purified Talc (16.67%) (5% of API)

3


Table 53: Formula composition with Cellulose acetate polymer as ER coating material with/without pore former (B# 63B, 62B) Batch No: 63B Batch No: 62B Sr. No. Ingredients mg/unit Sr. No. Ingredients mg/unit

Seal coat 5% w/w wt. gain Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100 1 Suigar spheres 25/30 100.0 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (80%) 4.0 3 Pearlitol 25 (32%) 1.6 3 Pearlitol 25 (10%) 0.5 4 Purified Talc (18%) 0.9 4 Purified Talc (10%) 0.5 5 P.Water (15% w/w Dispersion) 28 5 P.Water (22.73% w/w Dispersion) 17.0 Total 105.0 Total 105.0 Drug layering 173.33% w/w wt. gain Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 7 Topiramate (70% of 200mg) 140



148



21

9 Pearlitol 25 (33.33%) (10% of API)

14 9 Pearlitol 25 (33.33%) (10% of API) 14


7 10 Purified Talc (16.66%) (5% of API) 7

11 P.Water (20 % w/w Dispersion) 728 11 P.Water (20 % w/w Dispersion) 728 Total 287 Total 287 Seal coating 3% w/w wt. gain Seal coating 3% w/w wt. gain

12 Drug coated pellets 287 1 Drug coated pellets 287 13 Methocel E5LV (50%) 4.3 2 Methocel E5LV (50%) 4.3 14 Pearlitol 25 (32.56%) 2.8 3 Pearlitol 25 (32.56%) 2.8 15 Purified Talc (17.44%) 1.5 4 Purified Talc (17.44%) 1.5 16 P.Water (15% w/w dispersion) 48.7 5 P.Water (22.73 % w/w Dispersion) 29.2 17 Total 295.6 6 Total 295.6



15 Drug layerd seal coat pellet 295.6 13 Drug layerd seal coat pellet 295.6

16 Cellulose acetate (398-10) (88.9% of Total polymer)


31.03

17 PEG 4000 (11.1% of Total polymer)


6.64


4.43 16 Triethyl citrate (17.63% of Total polymer)

6.64

19 P.Water (8.6% of Total solvent) 38.37 17 P.Water (10.84% to Total solvent) 58


408.0 18 Acetone (89.16% to Total solvent) 477

21 Total (9% dispersion) 339.94 19 Total (7.65% w/w dispersion) 339.91 Drug layering 22.95% w/w wt. gain Drug layering 22.95% w/w wt. gain

22 ER coated pellet (CA) 339.94 20 ER coated pellet (CA) 339.91 23 Topiramate (30% of 200mg) 60 21 Topiramate (30% of 200mg) 60



9

25 Pearlitol 25 (33.33%) (10% of API)

6 23 Pearlitol 25 (33.33%) (10% of API) 6


3 24 Purified Talc (16.67%) (5% of API) 3

27 P.Water (20 % w/w Dispersion) 312 26 P.Water (20 % w/w Dispersion) 312 28 Total 417.94 Total 417.91

Manufacturing process parameter for Trial batch #63D, #63A, #63B & #62B were same

like trial batch no. 64 & 65 as mentioned above.



149

Table 54: Formula composition with Cellulose acetate polymer as ER coating material with pore former [B# 66] Batch No: 66

Sr. No. Ingredients mg/unit Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 5 P.Water (15% w/w Dispersion) 28 Total 105.0 Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 8 Methocel E5LV (50%) (15% of API) 21 9 Pearlitol 25 (33.33%) (10% of API) 14 10 Purified Talc (16.66%) (5% of API) 7 11 P.Water (20 % w/w Dispersion) 728 Total 287 Seal coating 3% w/w wt. gain

12 Drug coated pellets 287 13 Methocel E5LV (50%) 4.3 14 Pearlitol 25 (32.56%) 2.8 15 Purified Talc (17.44%) 1.5 16 P.Water (15 % w/w Dispersion) 48.7 17 Total 295.6 ER coat 16% w/w (12.74% w/w Polymer)

18 Drug layerd seal coat pellet 295.6 19 Cellulose acetate (398-10) (82.37% of Total polymer) 31.03 20 PEG 4000 (17.63% of Total polymer) 6.64 21 Talc (7.96% of Total polymer) 3.0 22 Triethyl citrate (17.63% of Total polymer) 6.64 23 P.Water (13.43% of Total solvent) 74.0 24 Acetone (86.57% of Total solvent) 477.0 25 Total (7.9% dispersion) 342.91 Drug layering 22.75% w/w wt. gain

26 ER coated pellet (CA) 342.91 27 Topiramate (30% of 200 mg) 60 28 Methocel E5LV (50%) (15% of API) 9 29 Pearlitol 25 (33.33%) (10% of API) 6 30 Purified Talc (16.67%) (5% of API) 3 31 P.Water (20 % w/w Dispersion) 312 32 Total 420.91



150

Manufacturing process parameters were similar as that of batch #63D, 63A, 63B & 62B

as mentioned above.

Effect of temperature and stress stability condition on dissolution profile of the cellulose

acetate coated pellets was evaluated to chose the suitable extended release polymer (B#

66).

3.5.6.3.2 Modified release coating with ER coating followed by DR coating (Three

drug layers)

3.5.6.3.2.1 ER coating with Cellulose acetate to PEG ratio of 82.37 : 17.63 followed

by DR coating

In second strategy of cellulose acetate ER coating, 70% of 200mg of Topiramate API was

loaded on seal coated pellets, followed by ER coating of cellulose acetate with polyethylene

glycol 4000 in the ratio of 82.37: 17.63 was used, followed by 15% of 200mg of

Topiramate API was loaded on ER coated pellets, followed by 15% & 25% w/w of Delayed

release (DR) coating with or without pore former. Finally, top coat with 15% of 200mg API

layering as immediate release portion at the surface of the DR coated pellets. Optionally,

two batches were coated with two different type of moisture protective coating. Here, drug

layering was distributed in three layers as mentioned above.

In DR coating, two different grades of delayed release polymer were utilized with and

without pore former to find out the suitable formulation design strategy of the test product

which could be pharmaceutically equivalent to Reference product (Trokendi XR 200mg).

Detailed composition of each strategy of the DR coated pellets with cellulose acetate as ER

coating is mentioned below;



151

A. DR coating of Eudragit S100 with or without pore former strategy

Table 55: DR coating of Eudragit S100 with or without pore former strategy (B# 63C & 65A) Batch No: 63C Batch No: 65A

Sr. No. Ingredients mg/unit


Seal coat 5% w/w wt. gain Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100 1 Suigar spheres 25/30 100 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 3 Pearlitol 25 (32%) 1.63 4 Purified Talc (18%) 0.9 4 Purified Talc (18%) 0.87 5 P.Water (15% w/w Dispersion) 28 5 P.Water (10% w/w Dispersion) 45 Total 105.0 Total 105.0 Drug layering 173.33% w/w wt. gain Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 7 Topiramate (70% of 200mg) 140



21

9 Pearlitol 25 (33.33%) (10% of API)

14 9 Pearlitol 25 (33.33%) (10% of API)

14



7

11 P.Water (20 % w/w Dispersion) 728 11 P.Water (20 % w/w Dispersion) 728 Total 287 Total 287 Seal coating 3% w/w wt. gain Seal coating 3% w/w wt. gain 1 Drug coated pellets 287 1 Drug coated pellets 287 2 Methocel E5LV (50%) 4.3 2 Methocel E5LV (50%) 4.3 3 Pearlitol 25 (32.56%) 2.8 3 Pearlitol 25 (32.56%) 2.8 4 Purified Talc (17.44%) 1.5 4 Purified Talc (17.44%) 1.5 5 P.Water (15% w/w dispersion) 48.7 5 P.Water (15 % w/w Dispersion) 48.7 6 Total 295.6 6 Total 295.6



13 Drug layerd seal coat pellet 295.6 13 Drug layerd seal coated pellet 295.6



31.03



6.64


6.64 16 Talc (7.96% of Total polymer) 3.0

17 P.Water (10.84% of Total solvent) 58.0 17 Triethyl citrate (17.63% of Total polymer)

6.64

18 Acetone (89.16% of Total solvent) 477.0 18 P.Water (13.43% of Total solvent) 74.0

19 Total (7.65% dispersion) 339.91 19 Acetone (86.57% of Total solvent)

477.0

Drug layering 11.5% w/w wt. gain 20 Total (7.9% dispersion) 342.91



152

20 ER coated pellet (CA) 339.91 Drug layering 11.37% w/w wt. gain 21 Topiramate (15% of 200mg) 30 21 ER coated pellet (CA) 342.91


4.5 22 Topiramate (15% of 200 mg) 30

23 Pearlitol 25 (33.33%) (10% of API)


4.5


1.5 24 Pearlitol 25 (33.33%) (10% of API)

3

26 P.Water (20 % w/w Dispersion) 156 25 Purified Talc (16.67%) (5% of API)

1.5

27 Total 378.91 26 P.Water (20 % w/w Dispersion) 156 DR coat 15% w/w wt. gain (12% w/w polymer) 27 Total 381.91

28 Drug layered ER coated pellet (CA)

378.91 DR coat 15% w/w wt. gain (12% w/w polymer)

29 Eudragit S 100 (80%) 45.48 28 ER coated pellet (CA) 381.91

30 Talc (10%) (12.45% of Polymer) 5.68 29 Eudragit S 100 (87.52% of Total polymer)

40.12

31 TEC (10%) (12.45% of Polymer) 5.68 30 Methocel E5LV[12.48% of Total polymer]

5.72

32 Acetone (10 % w/w Dispersion) 511.5 31 Talc [12.48% of Total polymer] 5.72 33 Total 435.75 32 TEC [12.48% of Total polymer] 5.72

Drug layering 8.95% w/w wt. gain 33 Acetone (88.66% of Total solvent)

453.5

34 DR coated pellets 435.75 34 Water (11.34% of Total solvent) 58 35 Topiramate (15% of 200mg) 30 Total (10.07% w/w dispersion) 439.19


4.5 Drug layering 8.88% w/w wt. gain

37 Pearlitol 25 (33.33%) (10% of API)

3 35 DR coated pellets 439.19


1.5 36 Topiramate (15% of 200 mg) 30

39 P.Water (20 % w/w Dispersion) 156 37 Methocel E5LV (50%) (15% of API)

4.5

40 Total 474.75 38 Pearlitol 25 (33.33%) (10% of API)

3


1.5




153

Table 56: DR coating of Eudragit S100 with different concentration of pore former and weight gain (B# 66A & 67B) Batch No: 66A Batch No: 67B



Seal coat 5% w/w wt. gain Seal coat 5% w/w wt. gain 1 Suigar spheres 25/30 100 1 Suigar spheres 25/30 100 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 4 Purified Talc (18%) 0.9 5 P.Water (15% w/w Dispersion) 28 5 P.Water (15% w/w Dispersion) 28 Total 105.0 Total 105.0 Drug layering 173.33% w/w wt. gain Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 7 Topiramate (70% of 200mg) 140



21

9 Pearlitol 25 (33.33%) (10% of API)

14 9 Pearlitol 25 (33.33%) (10% of API)

14



7

11 P.Water (20 % w/w Dispersion) 728 11 P.Water (20 % w/w Dispersion) 728 Total 287 Total 287 Seal coating 3% w/w wt. gain Seal coating 3% w/w wt. gain

12 Drug coated pellets 287 12 Drug coated pellets 287 13 Methocel E5LV (50%) 4.3 13 Methocel E5LV (50%) 4.3 14 Pearlitol 25 (32.56%) 2.8 14 Pearlitol 25 (32.56%) 2.8 15 Purified Talc (17.44%) 1.5 15 Purified Talc (17.44%) 1.5 16 P.Water (15 % w/w Dispersion) 48.7 16 P.Water (15 % w/w Dispersion) 48.7 Total 295.6 Total 295.6



17 Drug layerd seal coated pellet 295.6 17 Drug layerd seal coat pellet 295.6



21.32


6.64 19 PEG 4000 (17.62% to Total polymer)

4.56

20 Talc (7.96% of Total polymer) 3.0 20 Talc (7.96% to Total polymer) 2.06


6.64 21 Triethyl citrate (17.62% to Total polymer)

4.56

22 P.Water (13.43% of Total solvent) 74.0 22 P.Water (15% of Total solvent) 56.1


477.0 23 Acetone (85% of Total solvent) 317.9

Total (7.9% dispersion) 342.91 Total (8% dispersion) 328.1 Drug layering 11.37% w/w wt. gain Drug layering 11.89% w/w wt. gain

24 ER coated pellet (CA) 342.91 24 ER coated pellet (CA) 328.1 25 Topiramate (15% of 200 mg) 30 25 Topiramate (15% of 200 mg) 30



154



4.5

27 Pearlitol 25 (33.33%) (10% of API)

3.0 27 Pearlitol 25 (33.33%) (10% of API)

3



1.5

29 P.Water (20 % w/w Dispersion) 156.0 29 P.Water (20 % w/w Dispersion) 156 Total 381.91 Total 367.1



30 Drug layered ER coated pellet (CA)

381.91 36 Drug layered ER coated pellet (CA)

367.1

31 Eudragit S 100 (87.52% of Total polymer)

40.12 37 Eudragit S 100 (100% of Polymer)

73.42

32 Methocel E5LV (12.48% of Total polymer)

5.72 38 Talc (12.5% of Polymer) 9.177

33 Talc (12.48% of Total polymer) 5.72 39 TEC (12.5% of Polymer) 9.177 34 TEC (12.48% of Total polymer) 5.72 40 Acetone (35% of Solvent) 289.1


453.5 41 IPA (65% of Solvent) 536.9

36 IPA (7.94% of Total solvent) 40.6 Total [10% dispersion] 458.9 37 MDC (3.40% of Total solvent) 17.4 Drug layering 8.5% w/w wt. gain

Total (10.07% dispersion) 439.19 42 DR coated pellets 458.9 Drug layering 8.88% w/w wt. gain 43 Topiramate (15% of 200 mg) 30

38 DR coated pellets 439.19 44 Methocel E5LV (50%) (15% of API)

4.5

39 Topiramate (15% of 200 mg) 30 45 Pearlitol 25 (33.33%) (10% of API)

3



1.5

41 Pearlitol 25 (33.33%) (10% of API)



1.5 Total 497.9

43 P.Water (20 % w/w Dispersion) 156 Moisture barrier coat 6.63% w/w wt. gain

Total 478.19 48 IR Drug coated pellet 497.9 Moisture Barrier coat with AMB 49 Opadry 200 white 33.01

44 DR coated drug layered pellets 478.19 50 P.Water (16% dispersion) 173 45 Opadry AMB White 23.91 Total 530.9

46 Purified Water (10% w/w Dispersion)

215.19

Total 502.1



155

B. DR coating of Eudragit L30 D55 with different level of weight gain and drug

distribution

In second strategy of DR coating along with initially ER coating with Cellulose acetate to

PEG ratio of 82.37 : 17.63, Eudragit L30 D55 grade of delayed release polymer were

utilized without pore former with various weight gain of DR coating and drug

distribution ratio of three layers to find out the suitable formulation design strategy of the

test product which could be pharmaceutically equivalent to Reference product (Trokendi

XR 200mg).

B.1 DR coating weight gain of 15% & 13.79% along with drug distribution of three

layers from core to surface in the ratio of 70: 15: 15% of 200 mg Topiramate

Initially, DR coating weight gain was tried at 15% and 13.79% w/w level along with drug

distribution of 70: 15: 15 % of topiramate API from core to surface.



Table 57: DR coating weight gain of 15% & 13.79% along with drug distribution of three layers from core to surface in the ratio of 70: 15: 15% of 200 mg Topiramate (B.#68A & 70) Batch No: 68A Batch No: 70

Sr. No. Ingredients mg/unit Sr. No. Ingredients mg/unit

1 Suigar spheres 25/30 100 Drug layering 182% w/w wt. gain 2 Methocel E5LV (50%) 2.5 1 Sugar spheres 30/35 100 3 Pearlitol 25 (32%) 1.6 2 Topiramate (70% of 200mg) 140

4 Purified Talc (18%) 0.9 3 Methocel E5LV (50%) (15% of API)

21

5 P.Water (15% w/w Dispersion) 28 4 Pearlitol 25 (33.33%) (10% of API)

14

Total 105.0 5 Purified Talc (16.66%) (5% of API)

7

6 Seal coated pellets 105 6 P.Water (20 % w/w Dispersion) 728 7 Topiramate (70% of 200mg) 140 Total 282


21 ER coat 16% w/w (12.74% w/w Polymer)

9 Pearlitol 25 (33.33%) (10% of API)

14 7 Drug layerd pellet 282


7 8 Cellulose acetate (398-10) (82.38% of Total polymer)

29.6



156

11 P.Water (20 % w/w Dispersion) 728 9 PEG 4000 (17.62% of Total polymer)

6.33

Total 287 10 P.Talc (7.96% of Total polymer) 2.86

Seal coating 3% w/w wt. gain 11 Triethyl citrate (17.62% of Total polymer)

6.33

12 Drug coated pellets 287 12 MDC (15% of Total solvent) 77.8 13 Methocel E5LV (50%) 4.3 13 Acetone (85% of Total solvent) 441.05 14 Pearlitol 25 (32.56%) 2.8 14 Total (8% dispersion) 327.1

15 Purified Talc (17.44%) 1.5 Drug layering 11.92% w/w wt. gain 16 P.Water (15 % w/w Dispersion) 48.7 15 ER coated Pellets 327.1 17 Total 295.6 16 Topiramate (15% of 200 mg) 30.0



4.5

18 Drug layerd pellet 295.6 18 Pearlitol 25 (33.33%) (10% of API)

3.0



1.5


6.64 20 P.Water (20 % w/w Dispersion) 156

21 Talc (7.96% of Total polymer) 3.0 21 Total 366.1


6.64 DR coat 13.79% w/w (8.62% w/w polymer)

23 MDC (15%) 81.6 22 Drug coated pellet 366.1

24 Acetone (85%) 462.5 23 Eudragit L30 D55 (100% of polymer)

31.55

25 Total (8% dispersion) 342.9 24 P.Talc UM (50% of polymer) 15.77 Drug layering 11.37% w/w wt. gain 25 TEC (10% of polymer) 3.15

26 ER coated Pellets 342.9 26 Water 127.0 27 Topiramate (15% of 200 mg) 30.0 27 Total [28.44% dispersion] 416.59


4.5 Drug layering 9.36% w/w wt. gain

29 Pearlitol 25 (33.33%) (10% of API)

3.0 28 DR coated pellet 416.59


1.5 29 Topiramate (15% of 200 mg) 30.0

31 P.Water (20 % w/w Dispersion) 156 30 Methocel E5LV (50%) (15% of API)

4.5

32 Total 381.9 31 Pearlitol 25 (33.33%) (10% of API)

3.0

DR coat 15% w/w wt gain (9.37% w/w polymer)


1.5

33 Drug coated pellet 381.9 33 P.Water (20 % w/w Dispersion) 156

34 Eudragit L30 D55 (100% of Polymer)

35.8 Total 455.59

35 P.Talc UM (50% of Polymer) 17.9 36 TEC (10% of Polymer) 3.59 37 Water 141.0 38 Total [28.9% dispersion] 439.2



157

Drug layering 8.88% w/w wt. gain 39 DR coated pellet 439.2 40 Topiramate (15% of 200 mg) 30.0


4.5

42 Pearlitol 25 (33.33%) (10% of API)

3.0


1.5

44 P.Water (20 % w/w Dispersion) 156.0 Total 478.2

B.2 DR coating weight gain of 20% & 25% along with drug distribution of three

layers from core to surface in the ratio of 60: 15: 25

Secondly, Trials were taken with DR coating weight gain at 20% and 25% w/w level

along with drug distribution of 60: 15: 25 % of topiramate API from core to surface.

Detailed composition of each strategy of the DR coated pellets with cellulose acetate as

ER coating is mentioned below;

Table 58: DR coating weight gain of 20% & 25% along with drug distribution of three

layers from core to surface in the ratio of 60: 15: 25% of 200 mg Topiramate (B.#70A &

70B)

Batch No: 70A Batch No: 70B

Sr. No. Ingredients mg/unit Sr. No. Ingredients mg/uni

t Drug layering 156% w/w wt. gain Drug layering 156% w/w wt. gain 1 Sugar spheres 30/35 100 1 Sugar spheres 30/35 100 2 Topiramate (60% of 200mg) 120 2 Topiramate (60% of 200mg) 120



18

4 Pearlitol 25 (33.33%) (10% of API)

12 4 Pearlitol 25 (33.33%) (10% of API)

12



6

6 P.Water (20 % w/w Dispersion) 624 6 P.Water (20 % w/w Dispersion) 624 7 Total 256 7 Total 256



1 Drug layerd pellet 30/35 256 1 Drug layerd pellet 30/35 256



25.19



158



5.4

4 P.Talc (7.98% of Total polymer) 2.44 4 P.Talc (7.98% of Total polymer) 2.44


5.4 5 Triethyl citrate (17.65% of Total polymer)

5.4

6 MDC (15% of Total solvent) 66.3 6 MDC (15% of Total solvent) 66.3 7 Acetone (85% of Total solvent) 375.65 7 Acetone (85% of Total solvent) 375.36 8 Total (8% dispersion) 294.4 8 Total (8% dispersion) 294.4

Drug layering 13.25% w/w wt. gain Drug layering 13.25% w/w wt. gain

9 ER coated Pellets 294.4 9 ER coated Pellets 294.4 10 Topiramate (15% of 200 mg) 30.0 10 Topiramate (15% of 200 mg) 30.0



4.5

12 Pearlitol 25 (33.33%) (10% of API)

3.0 12 Pearlitol 25 (33.33%) (10% of API)

3.0



1.5

14 P.Water (20 % w/w Dispersion) 156 14 P.Water (20 % w/w Dispersion) 156 15 Total 333.4 15 Total 333.4

DR coat 20% w/w (12.02% w/w polymer) DR coat 25% w/w (15.02% w/w

polymer) 16 Drug coated pellet 333.4 16 Drug coated pellet 333.4

17 Eudragit L30 D55 (100% of polymer)

40.06 17 Eudragit L30 D55 50.08

18 P.Talc UM (49.85% of polymer) 19.97 18 P.Talc UM 24.96 19 TEC (16.63% of polymer) 6.66 19 TEC 8.32 20 Water 173.3 20 Water 216.6 21 Total [27.79% dispersion] 400.12 21 Total [27.79% dispersion] 416.79


22 DR coated pellet 400.12 22 DR coated pellet 416.79 23 Topiramate (25% of 200 mg) 50 23 Topiramate (25% of 200 mg) 50



7.5

25 Pearlitol 25 (33.33%) (10% of API)

5 25 Pearlitol 25 (33.33%) (10% of API)

5



2.5

27 P.Water (20 % w/w Dispersion) 260 27 P.Water (20 % w/w Dispersion) 260 Total 465.1 Total 481.8



159

3.5.6.3.2.2 ER coating with Cellulose acetate to PEG ratio of 60 : 40 followed by DR

coating

In another strategy of cellulose acetate ER coating, 70% of 200mg of Topiramate API was


glycol 4000 in the ratio of 60 : 40 was used, followed by 15% of 200mg of Topiramate API

was loaded on ER coated pellets, followed by 25% w/w of Delayed release (DR) coating

with DR coating polymer without pore former. Finally, top coat with 15% of 200mg API

layering as immediate release portion at the surface of the DR coated pellets. Drug

layering was distributed in three layers with ER coating and DR coating in between as

mentioned above.



Table 59: ER coating with Cellulose acetate to PEG ratio of 60:40 followed by DR

coating (B.# 68 & 68B)

Batch No: 68 Sr. No. Ingredients mg/unit

1 Suigar spheres 25/30 100 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 5 P.Water (15% w/w Dispersion) 28 Total 105.0 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 8 Methocel E5LV (50%) (15% of API) 21 9 Pearlitol 25 (33.33%) (10% of API) 14 10 Purified Talc (16.66%) (5% of API) 7 11 P.Water (20 % w/w Dispersion) 728 Total 287 Seal coating 3% w/w wt. gain

12 Drug coated pellets 287 13 Methocel E5LV (50%) 4.3 14 Pearlitol 25 (32.56%) 2.8 15 Purified Talc (17.44%) 1.5 16 P.Water (15 % w/w Dispersion) 48.7 17 Total 295.6 ER coat 11% w/w (8.76% w/w Polymer)

18 Drug layerd pellet 295.6



160

19 Cellulose acetate (398-10) (60% of Total polymer) 15.53 20 PEG 4000 (40% of Total polymer) 10.35 21 Talc (7.96% of Total polymer) 2.062 22 Triethyl citrate (17.62% of Total polymer) 4.56 23 MDC (15% of Total solvent) 56.1 24 Acetone (85% of Total solvent) 317.9 25 Total (8% dispersion) 328.1 Drug layering 11.89% w/w wt. gain

26 ER coated Pellets 328.1 27 Topiramate (15% of 200 mg) 30 28 Methocel E5LV (50%) (15% of API) 4.5 29 Pearlitol 25 (33.33%) (10% of API) 3 30 Purified Talc (16.67%) (5% of API) 1.5 31 P.Water (20 % w/w Dispersion) 156 32 Total 367.1 DR coat 25% w/w wt gain (20.84% w/w polymer)

33 Drug coated pellet 367.1 34 Eudragit S 100 (100% of Polymer) 76.49 35 Talc (10% of Polymer) 7.64 36 TEC (10% of Polymer) 7.64 37 Acetone (35% of Total solvent) 267.0 38 IPA (65% of Total solvent) 496.0 39 Total [10% dispersion] 458.9 Drug layering 8.5% w/w wt. gain

40 DR coated pellet 458.9 41 Topiramate (15% of 200 mg) 30.0 42 Methocel E5LV (50%) (15% of API) 4.5 43 Pearlitol 25 (33.33%) (10% of API) 3.0 44 Purified Talc (16.67%) (5% of API) 1.5 45 P.Water (20 % w/w Dispersion) 156.0 Total 497.9

3.5.6.3.2.3 ER coating with Cellulose acetate to PEG ratio of 90 : 10 followed by DR

coating

In further strategy of cellulose acetate ER coating, 70% of 200mg of Topiramate API was


glycol 4000 in the ratio of 90 : 10 was used, followed by 15% of 200mg of Topiramate API

was loaded on ER coated pellets, followed by 15% w/w of Delayed release (DR) coating

without pore former. Finally, top coat with 15% of 200mg API layering as immediate

release portion at the surface of the DR coated pellets. Drug layering was distributed in

three layers with ER coating and DR coating in between as mentioned above.



161

In DR coating, single grades of delayed release polymer was utilized without pore former to

find out the suitable formulation design strategy of the test product which could be

pharmaceutically equivalent to Reference product.



Table 60: ER coating with Cellulose acetate to PEG ratio of 90 : 10 followed by DR coating (B.# 71) Batch No: 71

Sr. No. Ingredients mg/unit 1 Sugar spheres 30/35 100 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 5 P.Water (15% w/w Dispersion) 28 Total 105.0 Drug layering 173.33% w/w wt. gain 6 Seal coated pellets 105 7 Topiramate (70% of 200mg) 140 8 Methocel E5LV (50%) (15% of API) 21 9 Pearlitol 25 (33.33%) (10% of API) 14 10 Purified Talc (16.66%) (5% of API) 7 11 P.Water (20 % w/w Dispersion) 728 Total 287 ER coat 15% w/w (12.24% w/w Polymer)

18 Drug layerd pellet 287

19 Cellulose acetate (398-10) (90% of Total polymer)

31.63

20 PEG 4000 (10% of Total polymer) 3.51 21 P.Talc UM (12.5% of Total polymer) 4.39

22 Triethyl citrate (10% of Total polymer)

3.51

23 MDC (15% of Total solvent) 74.24 24 Acetone (85% of Total solvent) 420.72 25 Total (8% dispersion) 330.0 Drug layering 11.82% w/w wt. gain

26 ER coated Pellets 330.0 27 Topiramate (15% of 200 mg) 30 28 Methocel E5LV (50%) (15% of API) 4.5 29 Pearlitol 25 (33.33%) (10% of API) 3



162

30 Purified Talc (16.67%) (5% of API) 1.5 31 P.Water (20 % w/w Dispersion) 156 32 Total 369.0 DR coat 15% w/w (9.37% w/w polymer)

33 Drug coated pellet 369.0 34 Eudragit L30 D55 34.59 35 P.Talc UM 17.29 36 TEC 3.47 37 Water 140.7 38 Total [20% dispersion] 424.4 Drug layering 9.19% w/w wt. gain

39 DR coated pellet 424.4 40 Topiramate (15% of 200 mg) 30 41 Methocel E5LV (50%) (15% of API) 4.5 42 Pearlitol 25 (33.33%) (10% of API) 3 43 Purified Talc (16.67%) (5% of API) 1.5 44 P.Water (20 % w/w Dispersion) 156 Total 463.4

3.5.6.3.3 Core drug layering modification with only ER coating (Two drug layers)

In third trial of cellulose acetate ER coating, drug layering composition were modified with

different concentration of low soluble salt and surfactant, followed by ER coating with

Cellulose acetate and Polyethylene glycol 4000 in the ratio of 80: 20, followed by

dissolution profile were evaluated at different dissolution condition to compare with

reference product’s profile. In these design, drug were distributed in two layers with ER

coating layer of cellulose acetate with pore former in between two drug layers

At initial trials, to check the feasibility only 70% of 200mg of Topiramate was loaded with

two different low soluble salts, then ER coated with cellulose acetate and polyethylene

glycol 4000 (80:20) upto 15% weight gain. Then dissolution test were performed in

multimedia and pH 6.8 Phosphate buffer.



163

Table 61: Core drug layering modification with only ER coating, no IR drug portion (B

#74A &74B) (Total topiramate 140mg/ Capsule)

Batch No: 74A Batch No: 74B Sr. No.

Ingredients mg/unit

Sr. No.

Ingredients mg/unit

1 Suigar spheres 30/35 100 1 Sugar spheres 30/35 100 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 4 Purified Talc (18%) 0.9

5 P.Water (15% w/w Dispersion) 28 5 P.Water (15% w/w Dispersion)

28



1 Seal coated pellet 30/35 105 1 Seal coated pellet 30/35 105 2 Topiramate (70% of 200mg) 140.0 2 Topiramate (70% of 200mg) 140.0



21.0

4 Pearlitol 25 (33.33%) (10% of API)

14.0 4 Pearlitol 25 (33.33%) (10% of API)

14.0



7.0

6 Sodium benzoate (41.43% of API)

58.0 6 Fumaric acid (41.43% of API)

58.0

7 P.Water (25% dispersion) 720 7 P.Water (25% dispersion) 720 Total 345 Total 345

ER coat 15% wt gain [Polymer 12.41%]

ER coat 15% wt gain [Polymer 12.41%]

7 Drug layerd pellet 337.5 7 Drug layerd pellet 337.5

8 Celluloseacetate (398-10) (80% of Total polymer)

33.52 8 Celluloseacetate (398-10) (80% of Total polymer)

33.52

9 PEG 4000 (20% of Total polymer)

8.38 9 PEG 4000 (20% of Total polymer)

8.38

10 P.Talc (12.79% of Total polymer)

5.36 10 P.Talc (12.79% of Total polymer)

5.36


3.352 11 Triethyl citrate (8% of Total polymer)

3.352

12 MDC (15% of Total solvent) 87.3 12 MDC (15% of Total solvent) 87.3

13 Acetone (85% of Total solvent) 495.0 13 Acetone (85% of Total solvent)

495.0

14 Total (8% dispersion) 388.11 14 Total (8% dispersion) 388.11



164

During subsequent trials, various concentration of sodium benzoate salt and another batch

with solubilizer (docusate sodium) were tried with drug layering suspension to check the

dissolution pattern of modified drug layering composition with ER coated pellets as

compared to reference product. In all the trials in this strategy, 85% of 200mg Topiramate

was loaded with different concentration of sodium benzoate and docusate sodium, then ER

coated with cellulose acetate and polyethylene glycol 4000 (80:20) upto 15% weight gain,

followed by 15% of 200mg topiramate was loaded as IR drug layer portion. Then

dissolution test were performed in multimedia and pH 6.8 Phosphate buffer to check the

dissolution pattern as compared to reference product.

Table 62: Core drug layering modification with only ER coating and IR drug portion (B

#75) (Total topiramate 200mg/ Capsule)

Batch No: 75 Sr. No. Ingredients mg/unit

Seal coating 5% w/w wt. gain 1 Sugar spheres 30/35 100 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 5 P.Water (15% w/w Dispersion) 28 Total 105.0 Drug layering 238.1% w/w wt. gain 1 Seal coated pellet 30/35 105 2 Topiramate (85% of 200mg) 170.0 3 Methocel E5LV (50%) (15% of API) 25.5 4 Pearlitol 25 (33.33%) (10% of API) 17.0 5 Purified Talc (16.66%) (5% of API) 8.5 6 Sodium benzoate (17.06% of API) 29.0 7 P.Water (25% dispersion) 750 Total 355 ER coat 15.06% wt gain [Polymer 12.5%] 8 Drug layerd pellet 355 9 Celluloseacetate (398-10) (80% of Total polymer) 35.5 10 PEG 4000 (20% of Total polymer) 8.86 11 P.Talc (12.51% of Total polymer) 5.55 12 Triethyl citrate (8% of Total polymer) 3.55 13 MDC (15% of Total solvent) 92.22 14 Acetone (85% of Total solvent) 522.58 15 Total (8% dispersion) 408.46



165

Drug layering 10.8% w/w wt. gain 16 ER coated Pellets 408.5 17 Topiramate (15% of 200mg) 30 18 Methocel E5LV (50%) (15% of API) 4.5 19 Pearlitol 25 (33.33%) (10% of API) 3 20 Purified Talc (16.66%) (5% of API) 1.5 21 Sodium benzoate (17.03% of API) 5.11 22 P.Water 132.33 23 Total (25% dispersion) 452.6

Table 63: Core drug layering modification with only ER coating and IR drug portion (B #76 &77) (Total topiramate 200mg/ Capsule) Batch No: 76 Batch No: 77

Sr. No. Ingredients mg/uni

t Sr.

No. Ingredients mg/unit

Seal coating 5% w/w wt. gain Seal coating 5% w/w wt. gain 1 Sugar spheres 30/35 100 1 Sugar spheres 30/35 100 2 Methocel E5LV (50%) 2.5 2 Methocel E5LV (50%) 2.5 3 Pearlitol 25 (32%) 1.6 3 Pearlitol 25 (32%) 1.6 4 Purified Talc (18%) 0.9 4 Purified Talc (18%) 0.9 5 P.Water (15% w/w Dispersion) 28 5 P.Water (15% w/w Dispersion) 28 Total 105.0 Total 105.0 Drug layering 223.33% w/w wt. gain Drug layering 223.59% w/w wt. gain 1 Seal coated pellet 30/35 105 1 Seal coated pellet 30/35 105.0 2 Topiramate (85% of 200mg) 170.0 2 Topiramate (85% of 200mg) 170.0

3 Methocel E5LV (42.86%) (15% of API) 25.5 3

Methocel E5LV (42.86%) (15% of API) 25.5

4 Pearlitol 25 (28.57%) (10% of API) 17.0 4

Pearlitol 25 (28.57%) (10% of API) 17.0

5 Purified Talc (28.57%) (10% of API) 17.0 5

Purified Talc (28.57%) (10% of API) 17.0

6 Sodium benzoate (2.94% of API) 5.0 6 Docusate Sodium (3.1% of API) 5.27 7 P.Water [25% dispersion] 703.5 7 P.Water [25% dispersion] 704.31 Total 339.5 Total 339.77

ER coat 14.68% wt gain [Polymer 12.18%]



9 Celluloseacetate (398-10) (80% of Total polymer)

33.1 9 Celluloseacetate (398-10) (80% of Total polymer)

33.1

10 PEG 4000 (20% of Total polymer) 8.26 10 PEG 4000 (20% of Total polymer) 8.26 11 P.Talc (12.5% of Total polymer) 5.17 11 P.Talc (12.5% of Total polymer) 5.17


3.31 12 Triethyl citrate (8% of Total polymer)

3.31

13 MDC (15% of Total solvent) 85.974 13 MDC (15% of Total solvent) 85.974 14 Acetone (85% of Total solvent) 487.2 14 Acetone (85% of Total solvent) 487.2 15 Total (8% dispersion) 389.34 15 Total (8% dispersion) 389.61



166

Drug layering 10.63% w/w wt. gain Drug layering 10.63% w/w wt. gain 16 ER coated Pellets 389.3 16 ER coated Pellets 389.6 17 Topiramate (15% of 200mg) 30 17 Topiramate (15% of 200mg) 30

18 Methocel E5LV (42.86%) (15% of API)

4.5 18 Methocel E5LV (42.86%) (15% of API)

4.5

19 Pearlitol 25 (28.57%) (10% of API)

3 19 Pearlitol 25 (28.57%) (10% of API)

3



3

21 Sodium benzoate (2.93% of API) 0.88 21 Docusate Sodium (3.1% of API) 0.93 22 P.Water 124.14 22 P.Water [25% dispersion] 124.29 23 Total (25% dispersion) 430.7 23 Total 431.0

3.5.6.3.4 Modified core with novel ER coating (Two drug layers)

In subsequent trials, combination of particular concentration of sodium benzoate and

docusate sodium were taken based on the reverse engineering of the reference product in

drug layering suspension to check the dissolution pattern with ER coated pellets as

compared to reference product. In all the trials in this strategy, 85% of 200mg Topiramate

was loaded with particular concentration of sodium benzoate and docusate sodium, then

two different strategies of ER coated were evaluated. One with cellulose acetate and

polyethylene glycol as PF-3 (70:30) upto 15% weight gain, followed by 15% of 200mg

topiramate was loaded as IR drug layer portion. Another trial with cellulose acetate, novel

ER polymer (ER-4) & polyethylene glycol (PF-3) in the ratio of 70:20:10 upto 16.25%

weight gain, followed by 15% of 200mg topiramate was loaded as IR drug layer portion.

Then dissolution test were performed in multimedia and pH 6.8 Phosphate buffer to check

the dissolution pattern as compared to reference product. Detailed composition of each

layer of the pellets with ethyl cellulose strategy is mentioned below;

Table 64: Modified core with novel ER coating (Two drug layers) (Batch #78 & 78A)

Batch No: 78 Batch No: 78A Sr. No. Ingredients mg/unit Sr.

No. Ingredients mg/unit

Seal coating 5% w/w wt. gain Seal coating 5% w/w wt. gain 1 Sugar spheres 30/35 161.9 1 Sugar spheres 30/35 161.9 2 Methocel E5LV (50%) 4.05 2 Methocel E5LV (50%) 4.05 3 Pearlitol 25 (32%) 2.59 3 Pearlitol 25 (32%) 2.59 4 Purified Talc (18%) 1.46 4 Purified Talc (18%) 1.46 5 P.Water (15% w/w Dispersion) 45.9 5 P.Water (15% w/w Dispersion) 45.9



167

Total 170.0 Total 170.0 Drug layering 223.59% w/w wt. gain Drug layering 223.59% w/w wt. gain 1 Seal coated pellet 30/35 170.0 1 Seal coated pellet 30/35 170.0 2 Topiramate (85% of 200mg) 170.0 2 Topiramate (85% of 200mg) 170.0

3 Methocel E5LV (42.86%) (15% of API) 25.5 3

Methocel E5LV (42.86%) (15% of API) 25.5

4 Pearlitol 25 (28.57%) (10% of API) 17.0 4

Pearlitol 25 (28.57%) (10% of API) 17.0

5 Purified Talc (28.57%) (10% of API) 17.0 5

Purified Talc (28.57%) (10% of API) 17.0

6 Sodium benzoate 5.293 6 Sodium benzoate 5.293 7 P.Water [25% dispersion] 704.4 7 P.Water [25% dispersion] 704.4 Total 404.8 Total 404.8



8 Drug layered pellet 404.8 8 Drug layered pellet 404.8

9 Cellulose acetate (70% of Total polymer)

35.42 9 Cellulose acetate (70% of Total polymer)

35.42

10 PEG (PF-3) (30% of Total polymer)

15.18 10 ER-4 (20% of Total polymer) 10.12

11 P.Talc (12.51% of Total polymer) 6.33 11 PEG (PF-3) (10% of Total polymer)

5.06


3.54 12 P.Talc (20% of Total polymer) 10.12

13 MDC (15% of total solvent) 104.31 13 Triethyl citrate 910% of Total polymer)

5.06

14 Acetone (85% of total solvent) 591.1 14 MDC (15% of Total solvent) 113.47 Total (8% dispersion) 465.26 15 Acetone (70% of total solvent) 529.53 Drug layering 8.9% w/w wt. gain 16 IPA (15% of Total solvent) 113.47

15 ER coated Pellets 465.3 Total (8% dispersion) 470.57 16 Topiramate (15% of 200mg) 30 Drug layering 8.8% w/w wt. gain

17 Methocel E5LV (42.86%) (15% of API)

4.5 17 ER coated Pellets 470.6

18 Pearlitol 25 (28.57%) (10% of API)

3 18 Topiramate 30


3 19 Methocel E5LV 4.5

20 Docusate Sodium 0.93 20 Pearlitol 25 3 21 Sodium benzoate 0.007 21 Purified Talc 3 22 P.Water [25% dispersion] 124.3 22 Docusate Sodium 0.93 Total 506.7 23 Sodium benzoate 0.007

24 P.Water [25% dispersion] 124.3 Total 512.0 Moisture barrier coat 5% wt gain 25 Drug layered Pellet 512.0 26 Opadry II White 85F18422 25.6 27 P.Water 10% 230.4 Total 537.6



168

3.5.7 MOISTURE BARRIER COATING OPTIMIZATION

From reference product composition [http://www.rxlist.com/script/main/art.asp?articlekey= 3285] and

literature survey, the need to protect Topiramate API and modified release coating design

to maintain the drug release profile on stability from moisture were identified. Hence, it

was decided to overcoat immediate release drug layered pellets by moisture barrier

coating. Looking at effectiveness of moisture barrier coating systems available

commercially, Opadry AMB, Opadry 200 & Opadry II white from Colorcon were

selected for trials. Preformulation study revealed that all the moisture barrier coating

systems are compatible with Topiramate. 5 % coating weight gain of moisture barrier

coat was decided for effective barrier properties using formula described in table 65 and

process described in table 66 & 67.

Required quantity of Opadry powder was weighed and dispersed under stirrer. Solution

was kept under stirrer for 45 minutes [http://www.colorcon.com/literature/marketing/fc/Opadry%20amb

/pi_opadry_amb_recon.pdf, http://www.colorcon.com/literature/marketing/fc/Opadry%20200/pi_opadry_200_recon.pdf, http://www.

colorcon.com/literature/marketing/fc/Opadry%20II/pi_opadry_II_recon.pdf]. The system which offers best possible

process efficiency & desired physicochemical parameters without affecting dissolution of

immediate release drug layer was selected. Gelatin capsules were filled with final coated

by automatic capsule filling machine and subjected for dissolution study.

Table 65: Formula for trials #66A, #67B & #78A

Sr. No.

Moisture Barrier coat with Opadry AMB (#66A)

Moisture barrier coat with Opadry 200 (#67B)

Moisture barrier coat with Opadry II white (#78A)

Ingredients mg/unit Ingredients mg/unit Ingredients mg/unit

1 IR Drug coated pellet 478.19 IR Drug coated pellet

497.9 IR Drug coated pellet

461.2

2 Opadry AMB White 23.91 Opadry 200 white 33.01 Opadry 200 white 33.01

3 Purified Water (10% w/w Dispersion)

215.19 Purified Water (16% dispersion)

173.30 Purified Water (16% dispersion)

173.30

Total 502.1 Total 530.9 Total 494.21



169

3.6 MANUFACTURING PROCESS SELECTION:

After preliminary feasibility trials and various bench scale formulation trails tentative

qualitative formula composition at each stage of pellets coating and their manufacturing

process parameters for topiramate ER capsules 200mg were finalized. In the next step,

Quantitative formula composition optimization shall be done by statistical optimization

techniques by using “Design of Expert” (DOE) software ver. 8.0.7.1 with the help

finalized manufacturing process parameters at each stage of pellets coating as mentioned

below;

3.6.1 MANUFACTURING PROCESS FLOW CHART FOR DOE BATCHES

PROCESS

1. Dissolve mannitol completely in Purified water 2. Add HPMC E5LV & Talc to step 1 under stirring 3. Take the #30/40 size fractioned sugar spheres and warm at 40-45ºC in FBP, then start coating with step 2 soln.

Seal Coating (15% Dispersion)

1. In 90% of water, add sodium benzoate, mannitol, HPMC E5LV, Topiramate API & talc under stirring. 2. Add step 1 soln. to step 2 under stirring 3. Rinse step 1 container with remaining 10% of water, add rinsed water to step 3 & stir 4. Take the #25/40 size fractioned sugar spheres and warm at 40-45ºC in FBP, then start drug layering with step 4 soln.

Drug Layering-I (25% Dispersion)

1. Add cellulose acetate slowly to Acetone under continuous stirring to get clear solution 2. Add ER-4 to step 1, stirr till almost clear solution 3. Add PF-3 to MDC under stirring to get clear solution. 4. Add step 3 to step 2 under stirring to get clear solution 5. Take the #18/30 size fractioned drug layered pellets and warm at 30-35ºC in FBP, then start ER coating with step 5 soln.

ER Coating (8% Dispersion)

PROCESS IN BRIEF

Dispensing Dispense of all the Raw materials accurately as per the dispensing sheet



170

3.6.2 MANUFACTURING PROCESS PARAMETERS

Table 66: Summary of Process parameters before spraying at each stage

Parameters Observations

Seal Coating

Drug layering

ER coating

IR Drug layering

Moisture barrier coat

Inlet Set Temperature (ºC)

50-60 55-65 35-45 55-65 60-65

Humidity 14% 14% 16% 14% 14% Process Type Wurster Bottom spray Filter shaking Asynchronous

Filter bag Cotton Cotton Nylon Cotton Nylon Tube Diameter 4 mm 4 mm 4 mm 4 mm 4 mm

Nozzle size 0.8 mm 1.2 mm 1.2 mm 1.2 mm 0.8 mm Note; Air distribution base plate was “C”

Table 67: Summary of Process parameters during spraying at each stage

Parameters Observations

Seal Coating

Drug layering

ER coating

Drug layering

Moisture barrier coat

Inlet Temp.(ºC) 50-55 55-65 35-45 55-65 60-65 Exhaust Temp.(ºC) 40-45 40-47 35-38 40-47 45-55 Product Temp.(ºC) 43-47 43-47 32-34 43-47 45-50 Blower drive (%) 50-55 50-75 45-55 50-75 65-75

Air flow (CFM/m/s) 50-55 50-65 55-65 50-65 60-70 Spray rate (gm/min) 4-7 4-20 4-16 4-15 4-5

Spray RPM 2-5 3-20 3-18 3-15 3-4 Atomization Pressure

(kg/cm2) 1.0 1.0-1.2 1.0-1.1 1.0-1.2 1.0-1.2

1. Prepare Drug layering solution with 25% dispersion as mentioned above 2. Take the #16/30 size fractioned ER Coated drug layered pellets and warm at 40-45ºC in FBP, then start drug layering with drug layering dispersion.

Drug Layering-II (25% Dispersion)

Top moisture barrier Coating (10% Dispersion)

1. Add Opadry II white with water under continuous stirring and stirr for 45 min (make 10% solid dispersion in waster) 2. Take #16/30 size fractioned drug layered -II coated pellets and warm at 45-49ºC in FBP, then start Top moisture barrier coating with Opadry II dispersion.



171

3.7 FORMULATION COMPOSITION OPTIMIZATION by DOE:

Formulation design and qualitative formulation composition at each stage of pellets

coating was finalized based on the satisfactory dissolution profiles in Multimedia and

OGD recommended dissolution condition. Final formula composition was optimized by

using statistical optimization technique with the help of “Design of Expert” (DOE)

software ver. 8.0.7.1. We have applied this optimization techniques only with Topiramate

ER capsules 200mg strength. Other strengths such as 100mg, 50mg & 25mg shall be dose

weight proportional of the final optimized composition of Topiramate ER capsules 200

mg. Top moisture barrier coat was not applied in all DOE batches as it is not rate

controlling polymer, hence dissolution shall not be effected with this coating.

3.7.1 Design and qualitative composition at each stage of DOE batches

Formulation Design of Topiramate ER capsules 200 mg is as follows;

Formulation Design

1. Sugar spheres mesh #30/35 (Diameter: 500 to 600 micron) 2. HPMC E5LV 3. Mannitol 4. Talc

Seal Coating (15% Dispersion)

1. Seal coated pellets 2. Topiramate API 6. HPMC E5LV 7. Mannitol 8. Talc 9. Sodium benzoate 10. Purified water

Drug Layering-I (25% Dispersion)

1. Drug layered pellets 2. Cellulose acetate 3. ER polymer- 4 4. Pore former (PF)- 3 5. Talc 6. Triethyl citrate 7. Dichloromethane 8. Acetone

ER Coating (8% Dispersion)

Qualitative composition



172

3.7.2 Factors and Responses for DOE batches

Factors are defined as the independent variables on which responses are dependent.

Responses are independent variables. In this formula composition optimization, each

ingredient which can modulate the drug release can be called as independent variables or

factors and drug release which is a result of each individual ingredient’s concentration or

the combination effect of different ingredients can be called as dependent variables or

responses. Factors, its levels and responses for this optimization studies are mentioned

below;

Table 68: Independent factors and responses for DOE trials

Sr. No.

Factors Unit Low Level

High Leve

l

Responses Unit

1 Drug at IR layer % 5 20 Multimedia dissolution at 2 hr % 2 Pore former (PF-3) % 0 20 Multimedia dissolution at 4 hr % 3 ER Polymer (ER-4) % 5 40 Multimedia dissolution at 8 hr % 4 ER Polymer coating

weight gain % 7.5 20 Multimedia dissolution at 16 hr %

5 pH 7.5 media dissolution at 2 hr %



1. ER coated pellets 2. Topiramate API 3. HPMC E5LV 4. Mannitol 5. Talc 6. Sodium benzoate 7. Docusate sodium 8. Purified water

Drug Layering-II (25% Dispersion)

Top moisture barrier Coating (10% Dispersion)

1. Opadry II white 2. Purified water



173

3.7.3 Formula composition of DOE batches

Response surface optimization technique with D-Optimal design was selected for the

DOE batches. As per the software generated data of response surface design, there were

total 25 nos. of experiments to be executed. As per the software generated data,

formulation composition were in percentage of each ingredient as the input unit for each

variables were in percentage, hence in actual dispensing sheet of each batch, percentage

was converted to milligram/ capsule unit. After analyzing the data by software, software

predicted the experimental error in the DOE run no. 13 batch, hence the dissolution study

of this batch was repeated and the results were entered at DOE run no. 26. Formula

composition of DOE batches are mentioned below;

Table 69: Formula composition of DOE batches as per software generated



174

Table 70: Design summary data generated by software

3.7.4 Analysis of DOE batches

Responses of the DOE batches were measured by the dissolution test in two different

conditions, one in Multimedia dissolution condition and the other one as per OGD

recommended dissolution condition in pH 7.5 phosphate buffer. Detailed dissolution

condition for the analysis of DOE batches are mentioned in Table 71 & 72.

Table 71: Multimedia dissolution condition for DOE batch analysis

Apparatus: USP Type I (Basket) Agitation: 100 RPM Volume: 900 ml

Medium pH 2.1 (0.01N HCL): 2 hr Followed by pH 6.8 phosphate buffer: 2, 6 & 14 hr.

Cumulative time points 2, 4, 8 & 16 hours

Table 72: pH 7.5 Phosphate buffer dissolution condition for DOE batch analysis

Apparatus: USP Type II (Paddle) Agitation: 50 RPM Volume: 750 ml Medium pH 7.5 phosphate buffer Cumulative time points 2, 4 & 8 hours



175

3.7.5 Interpretation from DOE software

Dissolution data of all the DOE batches were entered in the software, then analyzed all

individual responses as per the standard procedure and software’s instruction. After

analyzing all the responses, target range of dissolution profile were captured as per the

reference product’s dissolution profile at the same respective dissolution condition. Based

on the target desired profile, software has predicted the desired formula composition of

the Topiramate ER capsules 200 mg to get the similar dissolution profile in both the

media. Each responses were analyzed by using “Transformation, Fit-summary, Model,

ANOVA, Diagnostics and Model graph” tab icon. At the end of analysis & optimization

by the software, we got the “Design space” in which we can get the desired dissolution

profile. Inside the “Design space”, at any point by right click, we got the desired formula

composition which shall give the desired dissolution profile. We have selected two

formula composition from two separate design space, which are called as confirmatory

batch.

3.8 REPRODUCIBILITY STUDY/ CONFIRMATORY BATCH:

In order to determine robustness of formulation and process parameters, reproducibility

batch was taken. Pellets formulated at each stage were evaluated for physicochemical

parameters whereas process was evaluated for its efficiency. Stability study was

conducted on the same batch as per ICH storage conditions for the period of 6 month as

described in the protocol (refer section 3.9). Also, release kinetics study was performed

on dissolution data generated on this batch.

Two Confirmatory batch composition were selected from two separate Design space.

Dissolution profile of each confirmatory batch at each time point was predicted by

software. We had executed confirmatory batch and dissolution profile in two different

conditions as per DOE batches were performed. Then actual dissolution value and

predicted dissolution values were compared and checked the regression coefficient value.

Detailed formula composition, manufacturing process and their analysis are mentioned in

the following section.



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3.8.1 Formula composition of DOE confirmatory batches

Formula composition of two confirmatory batches were as follows;

Table 73: formula composition of confirmatory batches

Batch No: 105 Batch No: 106 Sr. No. Ingredients mg/unit


Seal coating 5% w/w wt. gain Seal coating 5% w/w wt. gain 1 Sugar spheres 30/35 161.9 1 Sugar spheres 30/35 161.9 2 Methocel E5LV (50%) 4.05 2 Methocel E5LV (50%) 4.05 3 Pearlitol 25 (32%) 2.59 3 Pearlitol 25 (32%) 2.59 4 Purified Talc (18%) 1.46 4 Purified Talc (18%) 1.46

5 P.Water (15% w/w Dispersion)

45.9 5 P.Water (15% w/w Dispersion)

45.9




6 Seal coated pellet 30/35

170.0 6 Seal coated pellet 30/35 170.0

7 Topiramate [80.96%] 161.92 7 Topiramate [93.9%] 187.80 8 Methocel E5LV 24.29 8 Methocel E5LV 28.17 9 Pearlitol 25 16.19 9 Pearlitol 25 18.78 10 Purified Talc 16.19 10 Purified Talc 18.78 11 Sodium benzoate 5.041 11 Sodium benzoate 5.847

12 P.Water [25% dispersion]

670.90 12 P.Water [25% dispersion] 778.14


ER coat 15.6% wt gain [Polymer 12%]

ER coat 15.6% wt gain [Polymer 12%]


14 Cellulose acetate ( [74.17%]

35.03 14 Cellulose acetate [72.46%]

37.34

15 ER-4 (20%) 9.45 15 ER-4 (20%) 10.31 16 PEG (PF-3) (5.83% ) 2.75 16 PEG (PF-3) (7.54% ) 3.89 17 P.Talc 9.45 17 P.Talc 10.31 18 Triethyl citrate 4.72 18 Triethyl citrate 5.15 19 MDC (15%) 105.93 19 MDC (15%) 115.55 20 Acetone (70%) 494.32 20 Acetone (70%) 539.22 21 IPA (15%) 105.93 21 IPA (15%) 115.55 Total (8% dispersion) 455.04 Total (8% dispersion) 496.36



22 ER coated Pellets 455.04 22 ER coated Pellets 496.36 23 Topiramate [19.04%] 38.08 23 Topiramate [6.1%] 12.20



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24 Methocel E5LV 5.71 24 Methocel E5LV 1.83 25 Pearlitol 25 3.81 25 Pearlitol 25 1.22 26 Purified Talc 3.81 26 Purified Talc 1.22 27 Docusate Sodium 1.180 27 Docusate Sodium 0.378 28 Sodium benzoate 0.00495 28 Sodium benzoate 0.00159 29 P.Water 157.78 29 P.Water 50.54 30 Total (25% Dispersion) 507.63 30 Total (25% Dispersion) 513.21 Barrier coat [4% wt gain] Barrier coat [4% wt gain]

31 Drug layered pellet 507.63 31 Drug layered pellet 513.21

32 Opadry II white 85F18422

20.31 32 Opadry II white 85F18422 20.53

33 P.Water 182.80 33 P.Water 188.30 Total (10% dispersion) 527.94 Total (10% dispersion) 533.74

3.8.2 Manufacturing process

Manufacturing process and process parameters were same as mentioned in section 3.6.1

& 3.6.2.

3.8.3 Analysis of DOE confirmatory batches

Modified release pellets of Topiramate ER capsules 200mg of DOE confirmatory batches

were evaluated physically as well as chemically as mentioned in the below section.

3.8.3.1 Physical analysis of Pellets of confirmatory batches

Evaluation of pellets must be done to obtain desired product performance. Parameters

Evaluated at different stages during manufacturing process are shown in table 74.

Table 74: Evaluation of pellets during manufacturing

Stage Manufacturing stage Evaluation parameter

I Seal coat on core sugar spheres • % practical yield

• Size distribution (% Fines & %

Agglumarates

• % LOD

• Bulk density

II Drug layering on seal coated pellets

III ER coat on drug layered pellets

IV IR Drug layering on ER coated pellets

V Moisture barrier coat



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3.8.3.1.1 Percent practical yield

Percent practical yield was calculated by the following formula after completion of each

layering process to see loses occurred during each step.

3.8.3.1.2 Size distribution

In order to determine particle size distribution of prepared pellets, 25 grams of pellets

were placed in lab sifter containing sieves with a close fitting receiving pan and cover.

The sieve sifter was vibrated for 20 minutes using vibratory sifter and weighing of pellets

was carried out from amount remaining in each sieve and in receiving pan.

3.8.3.1.3 Loss on drying

Loss on drying (LOD) of the dried pellets at the end of each stage of coating were

evaluated by taking approx. 5 gm of dried pellets of each stage and crushed them into

mortar and pastel, then check the % LOD in the IR moisture balance. This steps is very

critical to get reproducibility in drug release from the pellets at initial stage ane during

stability study.

3.8.3.1.4 Bulk Density

Bulk density of each stage pellets were evaluated to estimate the initial and final batch

size, that will help for the selection of the manufacturing equipment. Finished product i.e.

moisture barrier coated pellets were evaluated for the bulk density. Estimation of bulk

density helps in determining appropriate capsule size for formulation.

Bulk densities of all types of pellets were determined by pouring gently 25 grams of

sample through a glass funnel into a 100 ml graduated cylinder. The volumes occupied by

the sample were recorded. Bulk density was calculated. The measurements were done in

the triplicate.

3.8.3.2 Chemical analysis of capsules of confirmatory batches

Chemical analysis of the pellets were done with respect to Assay, Dissolution and Related

substances.



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3.8.3.2.1 Assay

Assay of drug layered pellets and finished product was determined by using HPLC

method as described in the analytical section.

3.8.3.2.2 Dissolution

Responses of the DOE confirmatory batches were measured by the dissolution test in two

different conditions, one in Multimedia dissolution condition and the other one as per

OGD recommended dissolution condition in pH 7.5 phosphate buffer. Detailed

dissolution condition for the analysis of DOE batches are mentioned in Table .

Table 75: Multimedia dissolution condition for DOE batch analysis

Apparatus: USP Type I (Basket) Agitation: 100 RPM Volume: 900 ml

Medium pH 2.1 (0.01N HCL): 2 hr Followed by pH 6.8 phosphate buffer: 2, 6 & 14 hr.

Cumulative time points 2, 4, 8 & 16 hours

Table 76: pH 7.5 Phosphate buffer dissolution condition for DOE batch analysis

Apparatus: USP Type II (Paddle) Agitation: 50 RPM Volume: 750 ml Medium pH 7.5 phosphate buffer Cumulative time points 2, 4 & 8 hours

3.8.3.2.2.1 Calculation of similarity factor (f2) [Guidance for Industry SUPAC-MR: Modified Release Solid

Oral Dosage Forms.(1997), U.S. FDA, CDER]

Similarity factor (f2)

Similarity factor was calculated to compare the test with reference release profiles. It was

calculated from mean dissolution data according to following equation.

Where LOG = logarithm to base 10, n = number of sampling time points, ∑ = summation

over all time points, Rt = dissolution at time point t of the reference product

Tt = dissolution at time point t of the test product



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Similarity factor (f2) Significance < 50 Test and reference profiles are dissimilar

50-100 Test and reference profiles are similar 100 Test and reference profiles are identical

>100 The equation yields a negative value

3.8.3.2.2.2 Release Kinetics study

To analyze the in-vitro release data various kinetic models were used to describe the

release kinetics. The Zero order rate equation (1) describes the systems where the drug

release rate is independent of its concentration [Hadjiioannou TP et al. (1993)]. The First order

equation (2) describes the release from system where release rate is concentration

dependent [Siepmann J et al. (2011)]. Higuchi (1963) described the release of drugs from

insoluble matrix as a square root of time dependent process based on fickian diffusion

equation (3).

• Zero-order kinetics

Q= k0t (1)

• First-order kinetics

Log C= log Co—kt/ 2.303 (2)

• Hixon-Crowel’s Cube-Root Equation (Erosion model)

(100—W) 1/3 = 1001/3—k3t (3)

• Higuchi’s Square Root of Time Equation (Diffusion model)

Q=k t1/2 (4)

• Korsmeyer-Peppas model equation (Diffusion/Relaxation model)

M t/Mo = K5tn (5)

Where, Q was % drug released at time t and k was release rate constants,

depending on the kinetic model used. Mt / Mo were the fractional drug released

into the dissolution medium and k was a constant incorporating the structural and

geometric characteristics of the tablet. The term ‘n’ was the diffusion constant that



181

characterizes the drug released transport mechanism. The n value is used to

characterize different release mechanisms as given below.

Diffusion exponent Overall solute diffusion mechanism

0.45 Fickian diffusion

0.45<n<0.89 Non-fickian diffusion

0.89 Case-II transport

n>0.89 Super case-II transport

To determine release kinetics following plots were made: cumulative % drug release vs.

time (zero order kinetic model); log cumulative of % drug remaining vs. time (first order

kinetic model); cumulative of % drug release vs. square root of time (Higuchi model); log

cumulative of % drug release vs. time (Korsmeyer model). The release mechanism of

from finished formulation was determined by comparing their respective correlation

coefficient.

3.8.3.2.3 Related substances

Related substance (Impurity profiling) of finished product was determined by using

HPLC method as described in the analytical section.

3.9 STABILITY STUDY AND PACK EVALUATION AT LAB-SCAL E:

Introduction

Stability testing of pharmaceutical formulations is one of the key aspects of formulation

development. It is performed at various stages of formulation development drug

substances and drug products. In early stages, accelerated stability testing (at relatively

higher temperatures and/or humidities) can be used for “worst case” evaluation to

determine what types of degradation products may be found after long term storage.

Testing under gentle conditions (long term shelf storage) and slightly elevated

temperatures can be used to determine products shelf life and expiration dates. During

stability testing the products are tested for appearance, assay, degradation products and

dissolution study.



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Objective

The purpose of stability testing is to provide evidence on how the quality of drug product

varies with time under the influence of a variety of environmental factors such as

temperature, humidity and light, and to establish shelf life for the drug product and

recommended storage conditions.

On the basis of the information obtained, storage conditions are recommended which will

guarantee maintenance of quality of product in terms of safety, efficacy and its

acceptability all through its shelf life.

3.9.1 Formulation composition of Stability batch

Final Trial batch was planned and executed for confirming robustness of the formulation.

This final trial batch #78A was charged for stability studies as described in the following

protocol using gelatin capsules which were filled in automatically capsule filling

machine.

Table 77: Formula composition of Stability batch (Batch #78A)

Batch No: 78A Sr. No. Ingredients mg/unit

Seal coating 5% w/w wt. gain 1 Sugar spheres 30/35 161.9 2 Methocel E5LV (50%) 4.05 3 Pearlitol 25 (32%) 2.59 4 Purified Talc (18%) 1.46 5 P.Water (15% w/w Dispersion) 45.9 Total 170.0 Drug layering 138.11% w/w wt. gain 1 Seal coated pellet 30/35 170.0 2 Topiramate (85% of 200mg) 170.0 3 Methocel E5LV (42.86%) (15% of API) 25.5 4 Pearlitol 25 (28.57%) (10% of API) 17.0 5 Purified Talc (28.57%) (10% of API) 17.0 6 Sodium benzoate (3.11% of API) 5.29 7 P.Water [25% dispersion] 704.4 Total 404.8



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ER coat 16.25% wt gain [Polymer 12.5%] 8 Drug layered pellet 404.8 9 Cellulose acetate (70% of Total polymer) 35.42 10 ER-4 (20% of Total polymer) 10.12 11 PEG (PF-3) (10% of Total polymer) 5.06 12 P.Talc (20% of Total polymer) 10.12 13 Triethyl citrate 910% of Total polymer) 5.06 14 MDC (15% of Total solvent) 113.47 15 Acetone (70% of total solvent) 529.53 16 IPA (15% of Total solvent) 113.47 Total (8% dispersion) 470.57 Drug layering 8.8% w/w wt. gain

17 ER coated Pellets 470.6 18 Topiramate 30 19 Methocel E5LV 4.5 20 Pearlitol 25 3 21 Purified Talc 3 22 Docusate Sodium 0.93 23 Sodium benzoate 0.007 24 P.Water [25% dispersion] 124.3 Total 512.0 Moisture barrier coat 5% wt gain

25 Drug layered Pellet 512.0 26 Opadry II White 85F18422 25.6 27 P.Water 10% 230.4 Total 537.6

3.9.2 Primary packing of Stability batch

Capsules were packed in three different packing condition as follows;

i. HDPE Bottle with 1 gm Silica Gel

ii. HDPE Bottle with 1 gm Molecular sieve

iii. Blister pack of Alu-Alu

iv. Blister pack of PVC/PE-Alu

3.9.3 Stability Protocols

Stability samples was charged on stability as per ICH stability condition for batch # 78A

only on accelerated and Zone IVB stability condition. Final confirmatory batch and Pilot



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bio-equivalent batch shall be loaded on all stability condition as per ICH stability

guideline.

Table 78: Stability study protocol as per ICH guideline [ICH Harmonised Tripartite Guideline,

Stability Testing of New Drug Substances and Products Q1A (R2), 2003]

Study Storage condition Minimum time period covered by data at submission

Long term 25/60% RH 5% RH or

30/65% RH 5% RH

12 months

Intermediate 30/65% RH 5% RH 6 months Accelerated 40/75% RH 5% RH 6 months

Item Name: Topiramate ER Capsules 200 mg, Protocol No. : FD/DSP/0067/00-14

Table 79: In-house Stability study protocol

3.9.4 Analysis of Stability sample

Stability samples were analyzed as per the Standard test method as mentioned in the final

analytical method section. Four parameters such as Assay, Related substances,

Batch No.

Pack

No. of pack per

station

No. of samples

per pack

Reason for

Keeping

Storage condition

0C / % RH

Date of Incubat

ion

Due date

1M 2M 3M 6M

F101\04-260514-078

A

HDPE Bottle with 1 gm Silica

Gel

1

30 Capsule

s Product stability Study

400C / 75% RH

13-Jun-2014

13- Jul -2014

13-Aug-2014

13- Sep-2014

13- Dec-2014

HDPE Bottle with 1 gm Mol

Silica

1 NA

HDPE Bottle with 1 gm Silica

1 300C / 75%

RH NA

13- Sep-2014

Alu-Alu Blister

5 400C / 75% RH 13-

Jul-2014

13-Aug-2014

13- Sep-2014

PVC\ PE Blister

3

F101\04-260514-078

AP

HDPE Bottle

1 10 Gms

400C / 75% RH

1 300C / 75%

RH NA



185

Dissolution and water by Kf were analyzed at the specified time point of the stability

samples at accelerated and Zone IV B stability condition.

3.10 SCALE-UP / PROCESS EVALUATION BATCH:

3.10.1 Formulation composition of Scale-up batch

One strategy was selected for scale up batch based on satisfactory multimedia dissolution

and OGD recommended dissolution profile of the development batches. Formulation

composition of each strategies are mentioned below;

Table 80: Strategy-1: IR-19.04%, CA-74.17%, ER-4-20%, PF-3-5.83%, ER coating Polymer wt gain-12%] (Batch No. #ACS00114)

Sr. No.

Item Code

Ingredients Source Grade %w/w Qty/unit (mg)

Std. Qty/ Batch (g)

Overages $ Qty/

Batch (g) A. Seal coat 5% w/w (15% w/w Dispersion) 50%

1 RE230 Sugar spheres #30/35 Werner USP-NF 95.240 161.910 7000.000 7350.00

(5% OA)

2 RE191 Hydroxypropyl methyl cellulose E5

Dow USP-NF 2.380 4.050 175.100 262.65

3 RE113 Mannitol Roquette USP 1.550 2.640 114.140 171.21 4 RE405 Talc Luzenac Pharma Imerys Ph. Eur 0.830 1.410 60.960 91.44 5 RE355 Purified water * In-House In-House Q.S. 45.870 1983.140 2974.71 Total 100.00 170.010 7350.200

B. Drug coat 131.55% w/w (25% w/w Dispersion) 10% 1 NA Seal coated pellet #25/35 In-House In-House 43.180 170.010 7140.000 LOT-1 Drug Layering 2 RA075 Topiramate [80.96%] Hetero USP 20.570 80.960 3400.120 3740.13


Dow USP-NF 3.085 12.145 510.060 561.10

4 RE113 Mannitol Roquette USP 2.056 8.095 339.970 373.97 5 RE405 Talc Luzenac Pharma Imerys Ph. Eur 2.056 8.095 339.970 373.97 6 RE054 Sodium benzoate Avantor USP-NF 0.643 2.521 105.870 116.46 7 RE355 Purified water * In-House In-House Q.S. 335.450 14088.070 15496.88 LOT-2 Drug Layering 8 RA075 Topiramate [80.96%] Hetero USP 20.570 80.960 3400.120 3740.13


Dow USP-NF 3.085 12.145 510.060 561.10

10 RE113 Mannitol Roquette USP 2.056 8.095 339.970 373.97 11 RE405 Talc Luzenac Pharma Imerys Ph. Eur 2.056 8.095 339.970 373.97 12 RE054 Sodium benzoate Avantor USP-NF 0.643 2.521 105.870 116.46 13 RE355 Purified water * In-House In-House Q.S. 335.450 14088.070 15496.88



186

Total 100.00 393.641 16531.980 C. Extended Release (ER) coat 15.6% w/w [Polymer 12% w/w] (8% w/w Dispersion) 20%

1 NA Drug layerd pellets (Step B)

In-House In-House 86.510 393.641 8000.140

2 RE088 Cellulose acetate [74.17%]

Eastman USP-NF 7.700 35.030 711.930 854.32

3 RE078 ER Polymer-4 (20%) Evonik USP-NF 2.070 9.450 192.060 230.47

4 RE311 Polyethylene glycol (PF-3) (5.83% )

Clariant USP 0.600 2.750 55.890 67.07

5 RE405 Talc Luzenac Pharma Imerys Ph. Eur 2.080 9.450 192.060 230.47 6 RE060 Triethyl citrate Merck USP-NF 1.040 4.720 95.930 115.12 7 RE294 Dichloromethane (15%) SDFCL USP Q.S. 105.930 2152.860 2583.43 8 RE293 Acetone (70%) SDFCL USP Q.S. 494.320 10046.280 12055.54 9 RE448 Iso-propyl alcohol (15%) SDFCL USP Q.S. 105.930 2152.860 2583.43 Total 100.00 455.041 9248.010

D. Immediate Release (IR) Drug Coat 11.56% w/w (25% w/w Dispersion) 5% 1 NA ER coated Pellets In-House In-House 89.639 455.041 7999.880 2 RA075 Topiramate [19.04%] Hetero USP 7.501 38.080 669.470 702.94


Dow USP-NF 1.124 5.710 100.390 105.41

4 RE113 Mannitol Roquette USP 0.751 3.810 66.980 70.33 5 RE405 Talc Luzenac Pharma Imerys Ph. Eur 0.751 3.810 66.980 70.33

6 RE385 Docusate Sodium Techno drugs

USP 0.233 1.180 20.750 21.79

7 RE054 Sodium benzoate Avantor USP-NF 0.001 0.005 0.088 0.09 8 RE355 Purified water * In-House In-House Q.S. 157.780 2773.860 2912.55 Total 100.00 507.636 8924.538

E. Barrier coat 4% w/w (10% w/w Dispersion) 20% 1 NA IR Drug layered pellet In-House In-House 96.150 507.636 8000.090 2 RC332 Opadry II white Colorcon In-House 3.850 20.310 320.080 384.10 3 RE355 Purified water * In-House In-House Q.S. 182.800 2880.840 3457.00 Total 100.00 527.946 8320.170

F. Lubrication 0% 1 NA Barrier coated pellet In-House In-House 99.750 527.946 8000.000 2 RE405 Talc Luzenac Pharma Imerys Ph. Eur 0.250 1.320 20.000 20.00 Total 100.00 529.266 8020.000

G. Capsule filling

1 RE280 HGC shell white(op),body ivory opaque size 00 INH

ACG-Associated capsules

In-House NA 1.000 6000.000 NA



187

3.10.2 Manufacturing process flow chart of Scale-up batch

FLOW CHART FOR MANUFACTURING OF TOPIRAMATE ER PELLE TS

PROCESS

1. Dissolve mannitol (Pearlitol 25C) in purified water under continuous stirring 2. Add Methocel E5 LV to step 1 under continuous stirring, stirr till to get clear solution . 3. Disperse Talc to step 2 under continuous stirring.

Seal Coating

1. Prepare Drug layering solution in two lots, procedure for each lot is mentioned below; 2. Add sodium benzoate, pearlitol 25C & Methocel E5 LV one by one under continuous stirring. Stirr till to get clear solution 3. Add Topiramate API to step 5 solution under continuous stirring. 4. Rinse the API containing polybag with talc. 5. Disperse the talc in step 6 suspension under continuous stirring.

Drug Layering-I

1. Disperse Cellulose acetate in Acetone under stirring. Stirr till to get clear solution. 2. Add ER-4 to step 1 under stirring to get clear to hazy soln. 3. Dissolve PF-3 in Dichloromethane under stirring 4. Add Step 3 soln. to step 2 solution under stirring 5. Add Triethyl citrate to Step 4 solution under stirring. 6. Rinse the step 5 and step 3 container with IPA, then add the same IPA to Step 5 solution under stirring to get clear soln. 7. Finally add Talc to step 6 solution under continuous stirring.

ER Coating

1. If Drug layering-I soln. remains, then use the same or prepare fresh Drug layering soln. 2. Warm purified water to 60ºC to 80ºC under stirring 3. Disperse docusate sodium to step 2 under stirring and stirr continuously till get the clear solution 4. Take out step 3 soln. from hot plate and stirr at RT to reduce temp of the step 3 soln.. 5. Add sodium benzoate, pearlitol 25C & Methocel E5 LV one by one under continuous stirring. Stirr till to get clear solution 6. Add Topiramate API to step 5 solution under continuous stirring. 7. Rinse the API containing polybag with talc. 8. Disperse the talc in step 6 suspension under continuous stirring.

Drug Layering-II

PROCESS IN BRIEF

Sifting

1. Sift the Sugar pellets #30/35 through ASTM#30 and ASTM #35 mesh. 2. Collect the Sugar pellets passed through ASTM#30 and retained on ASTM #35 mesh in double polybag.



188

3.10.3 Analysis of Scale-up / Process evaluation batch

Scale up batches were analyzed for drug loading assay, dissolution profile after ER

coating & finished product’s dissolution profile in comparison with reference product.

3.11 SURFACE MORPHOLOGY EVALUATION BY SEM:

Finished product of Reference product and test product were evaluated for surface

morphology and cross-section appearance by imaging through Scanning Electron

Microscopy (SEM). Surface morphology and cross-section of final coated pellets are very

important to understand the surface porosity and inside porosity of the finished product of

coated pellets to understand the drug release behaviour of the reference product and to

match the drug release behaviour of the test product.

Surface morphology was evaluated for one of the DOE batch of batch no. #79, which

qualitative composition was similar as that of confirmatory batch of test product, hence

surface morphology and cross-section of the test product was considered as similar as

that of final confirmatory batch.

Moisture barrier Coating

1. Add Opadry II white 85F18422 coating material to purified water (10% w/w solid dispersion) under continuous stirring. 2. Keep step 1 dispersion under continuous stirring for 45 minute. 3. Take step 2 dispersion for moisture barrier coating.

Lubrication

1. Take 8.0 Kg (approx.) pellets into 25 Liter Bin-blender 2. Add 0.25% w/w of Talc to the coated pellets in the Step 1 Bin-blender 3. Lubricated for 10 min at Slow rpm (5 rpm).

Capsule filling

1. Fix the capsule size “00” change parts to Minicap capsule filling machine. 2. Adjust the capsule fill weight during intial machine setting. 3. Fill approx 5000 capsules of Topiramate ER capsules 200mg strength.



189

3.12 IN-VIVO PHARMACOKINETIC EVALUATION:

For selective and fast determination of TPM, liquid chromatography–mass spectrometry

(LC-MS) or LC-MS/MS has become the preferred choice. LC-MS/MS is considered a

gold standard technique for drug analysis in biological fluids. The high sample

throughput, selectivity and sensitivity for analytes of interest increase the applicability of

mass spectrometry in Pre-clinical and clinical studies.

Figure 19 structure of (a) Topiramate (b) Diclofenac

Several LC-MS/MS bioanalytical methods for topiramate were reported. LC–MS

methods had been reported with sensitivities and linearity ranges of 0.625–40 µg/mL [Chen

and Carvey, (1999), 2001; Britzi et al., (2003)] and 0.02–20 µg/mL for LC-MS/MS using atmospheric

pressure chemical ionization (APCI). An LC-MS/MS method by D. Goswami et

al.[Goswami D et al., (2009)] achieved a limit of quantitation (LOQ) of about 20 ng/mL. Moreover

an LC-MS/MS method that achieved an LOQ of 9.98 ng/mL yet there were no supporting

method validation exercises, and the involvement of costly deuteriated standard. The

objective of the present study was to develop and validate a sensitive bioanalytical

method for the routine quantitation of topiramate (TPM) in rabbit plasma.

Therefore the prime objective was to develop a sensitive LC-MS/MS method:

• with an LOQ around 10 ng/mL with no metabolite interference;



190

• to achieves a dynamic linearity with complete validation as per USFDA regulatory

requirement;

• that supports pharmacokinetic profiling by a bioequivalence study.

3.12.1 Bio-analytical methods of In-vivo samples

3.12.1.1 Chemicals and materials

Topiramate (C12H21NO8S; M.W. 339.36; purity >99%) [Fig.1 (a)] and diclofenac [Fig.1

(b)] were provided by the Sigma-Aldrich, St Louis, MO, USA.). HPLC grade methanol

(MeOH), n-hexane, ethyl acetate (GR grade), formic acid (AR grade) were purchased

from Merck Pvt. Ltd. (India). Ultrapure water was obtained from a Milli-Q PLUS PF

water purification system. All other reagents were of analytical grade and obtained from

standard commercial suppliers.

3.12.1.2 Chromatographic and mass spectrometric conditions

The Waters HPLC system, Milford USA consisted of a quaternary pump (600), auto

sampler (2707). The chromatographic separation was achieved on Thermo Betasil C18

column (50 × 2.1 mm, 3 µm) using methanol: 0.1 % formic acid (90:10, v/v) as mobile

phase at a flow rate of 0.4 mL/min. The samples (20 µL) were injected through

auto-sampler on to the LC-MS/MS system.

Mass spectrometric detection was performed on an API 4000 Qtrap mass spectrometer

(Applied Biosystems, MDS Sciex Toronto, Canada) equipped with an API electrospray

ionization (ESI) source. The mass spectrometer parameters, such as temperature, gas

pressure, voltage, etc., were optimized by infusing each analyte and the internal standard

(IS) using a 500 ng/mL solution in 50% methanol via a Harvard ‘11’ standard infusion

syringe pump (Harvard Apparatus, South Natick, MA, USA).

3.12.1.3 Preparation of reagents and working standard solutions

The stock solutions (1 mg/mL) of topiramate and diclofenac (IS) were prepared in

methanol. The stock solutions were diluted with methanol to make working standard

solutions which were further diluted to prepare the calibration standards and quality

control samples (QC). Calibration standards were prepared by spiking 5 µL of working



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standard solution into 95 µL of rabbit plasma to obtain a concentration range of

6.25-1600 ng/mL. QC samples of three different concentrations (6.25, 15, 300, 1400

ng/mL) viz., lower limit of quantification (LLOQ), low quality control (LQC), middle

quality control (MQC) and high quality control (HQC), were prepared separately in five

replicates, independent of the calibration standards. IS (1 mg/mL) was diluted by

methanol to get final concentration of 2 µL. Calibration Standards (CS) and QCs samples

were prepared by spiking appropriate working stocks in blank plasma. All the stocks were

taken 10 times of required concentrations to meet final CS and QCs samples requirement

and they were found stable for complete validation.

3.12.1.4 Sample preparation

A liquid-liquid extraction method was used for extraction of analyte from rabbit plasma.

To 90 µL of plasma, 10 µL of drug and 10 µL of IS (2 µL) were added in 5 mL of tubes

and mixed on cyclomixer (Spinix Tarsons, Kolkata, India) for 15 seconds. In case of

blank sample instead of 10 µL of drug, methanol was added. Following it, 3 mL of

extraction solvent (n-hexane and ethyl acetate, 50:50, v/v) was added to blank/spiked

plasma. The mixture was then vortex mixed for 10 min, followed by centrifugation for 10

min at 4000 RPM at 5 °C on Sigma 3-16K (Frankfurt, Germany). The organic layer (2.5

mL) was separated and evaporated to dryness under vacuum in speed vac concentrator

(Savant Instrument, Farmingdale, USA). The residue was reconstituted with 100 µL of

methanol thereby vortexing for 30 seconds and from this, 20 µL was injected mass

spectrometer via an auto sampler.

3.12.2 In-vivo Pharmacokinetic study protocol

In-vivo Pharmacokinetic study was done on scale-up batch of topiramate ER capsules

200 mg (Batch # ACS00114) along with reference product, Trokendi XR 200 mg to

evaluate the bio-equivalent potential of the test product with respect to reference product.

Per oral (PO) pharmacokinetic studies of formulation were performed in NZ rabbits (n =

3, weight range 2.5-3.2 Kg). The rabbits were housed in restraining cages and kept in

hygienic conditions, temperature 23-25 ºC, relative humidity 50-70% and 12/12 hr



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light/dark cycle. The rabbits were fasted overnight (12 hr) with free access to water.

Capsules filled with Topiramate granules were administered orally at dose of 10.33mg/kg

body weight to rabbit, followed by distilled water to swallow the capsule. In all cases the

same dose strength was given to the rabbit in both study groups for both IR and ER

capsules. Blood samples (0.5 mL) were collected from the marginal ear vein of each

rabbit in heparinized tubes at 0.25, 0.5, 0.75, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0, 12.0, 24.0, 48.0,

72 and 96.0 hr post-dosing. Plasma was collected by centrifuging the blood samples at

4000 rpm for 10 min and stored at -70 ± 10 °C until the analysis.

Chapter 3: Materials and Methods - Information and Library...

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