International Conference and Expo on Separation Techniques August 2015

Modern Methods for the Separation of Enantiomers

- from Kilos to Tons -

CHIRAL TECHNOLOGIES INC.

West Chester, PA.

- Over 80% of drug candidates contain at least one chiral center

- Increasingly complex molecules, requiring more advanced production methodologies

-Three General Strategies-Chiral Pool-Asymmetric Synthesis-Resolution

Chirality in Drug Pipeline

• Is there an optimal approach to problem?

• No – each stage is driven by different imperatives, therefore choices are also different

Challenge

• Short-term Focus–Speed is key–Cost less of an issue

• Pragmatic approach–Produce racemate then separate–Less effort on asymmetric synthesis, chiral pool (only if quick and easy)

Pre-Clinical

• Long-term focused – Scalability, cost, efficiency, robustness

• “Tool Box” Approach– Cannot assume that any approach is invalid– Test all, then run economic feasibility

Clinical

• Used at all stages– Classical Resolution– Chiral Chromatography

Chiral Separation

• Used at all stages– Classical Resolution– Chiral Chromatography

Chiral Separation

• Chromatography is considered to be:

– Last Resort– Temporary Solution– Inelegant– Difficult to Use

Perceptions of Chromatography

• Chromatography is;

– Cost effective– Reliable– Scalable

Reality of Modern Chromatography

Scalable Technology

Photo courtesy of AMPAC

Methods are developed on analytical columns

Scalable Technology

Photo courtesy of AMPAC

Ampac Fine Chemicals

• Screen compound– Chiral Stationary Phase (CSP)– Mobile Phase

• Determine Optimum Combination• Perform Loading Study• Run Stability Tests• Productivity = kg enantiomer/kg CSP/day

Chiral Chromatography Method Development

• Solubility characteristics• Stability (chemical and stereo)• Presence of other impurities• API or intermediate• Ability to racemize non-target enantiomer

Key Points to Consider

RO

OOR

ORO n RO

O

OR

OR

O

n

Amylose-based Cellulose-based

-RNatureCSP -RNatureCSP

ImmobilizedCHIRALPAK IA

ImmobilizedCHIRALPAK IB

ImmobilizedCHIRALPAK IC

NH

O CH3

CH3

NH

O CH3

CH3

NH

O Cl

Cl

CHIRALPAK ID Immobilized NH

O Cl

ImmobilizedCHIRALPAK IE NH

O Cl

Cl

Chiral Stationary Phase

ImmobilizedCHIRALPAK IF NH

O Cl

CH3

Screening Study a-Methyl-a-Phenylsuccinimide

EtOAc

THF/Hexane

MTBE

min0 5 10 15 20 25 30 35

mAU

0

20

40

60

80

100

120

NH

OO

Multiple separation opportunitiesAlso separates with conventional solvents. Note, zero THF selectivity

CHCl3

ACN:IPA 85:15

CHIRALPAK IA, 250 x 4.6 mmFlow rate 1 ml/minUV detection 254 nm

3.9

8.3

0 1 2 3 4 5 6 7 8 9 10

Retention Time (min)

0.0

0.1

0.2

0.3

0.4

0.5

Absorbance (AU)

Analytical injection

Dichloromethane/THF 70:30F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 5 µm CSP)Solubility in mobile phase: 45 g/L

Chiral Separation of EMD-53986

NH

N

NH

O

S

EMD-53986Precursor for Ca-sensitizing drug

3.9

8.3

0 1 2 3 4 5 6 7 8 9 10

Retention Time (min)

0.0

0.1

0.2

0.3

0.4

0.5

Absorbance (AU)

loading

16mg

20mg

4mg

8mg

12mg

Dichloromethane/THF 70:30F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 5 µm CSP)Solubility in mobile phase: 45 g/L

Loading Study for EMD-53986

3.9

8.3

0 1 2 3 4 5 6 7 8 9 10

Retention Time (min)

0.0

0.1

0.2

0.3

0.4

0.5

Absorbance (AU)

loading

16mg

20mg

4mg

8mg

12mg

Dichloromethane/THF 70:30F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 5 µm CSP)Solubility in mobile phase: 45 g/L

Loading Study for EMD-53986

3.9

8.3

0 1 2 3 4 5 6 7 8 9 10

Retention Time (min)

0.0

0.1

0.2

0.3

0.4

0.5

Absorbance (AU)

loading

16mg

20mg

4mg

8mg

12mg

Dichloromethane/THF 70:30F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 5 µm CSP)Solubility in mobile phase: 45 g/L

Loading Study for EMD-53986

3.9

8.3

0 1 2 3 4 5 6 7 8 9 10

Retention Time (min)

0.0

0.1

0.2

0.3

0.4

0.5

Absorbance (AU)

loading

16mg

20mg

4mg

8mg

12mg

Dichloromethane/THF 70:30F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 5 µm CSP)Solubility in mobile phase: 45 g/L

Loading Study for EMD-53986

3.9

8.3

0 1 2 3 4 5 6 7 8 9 10

Retention Time (min)

0.0

0.1

0.2

0.3

0.4

0.5

Absorbance (AU)

loading

16mg

20mg

4mg

8mg

12mg

Dichloromethane/THF 70:30F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 5 µm CSP)

Estimated productivity:2.8kg enantiomer/kg

CSP/day

Solubility in mobile phase: 45 g/L

Loading Study for EMD-53986

Glutethimide

Productivity:> 11 kg enantiomer/kg CSP/day

0 1 2 3 4 5 6 7 8

min

9 10 11

54 mg42 mg36 mg30 mg15 mg

Ethyl acetate 100%F = 1 mL/min, 25°C

(Column 25 x 0.46 cm, 20 µm CSP)

Solubility in mobile phase: 300 g/L

Productivity demonstrated under SMB conditions

• Two Clinical Development Projects

1) Continuous Enantio-Enrichment

2) Stage-Appropriate Technology

Case Studies

• Biogen Idec Alzheimer’s Drug

- BIIB042- Two chiral centers- Continuous process developed

1) Continuous Enantio-Enrichment

BIIB042 Structure

*

*

OH

BIM-651

N

F

OH

N

F

OTf

N

F

CF3

BIO-20377

N

F

CF3

Chiralseparation

+NH CHO

F+

Mannich Triflation

Suzuki Hydrolysis

N

F

CF3

BIIB042

90%

60-80% 100%15-18%

70-80%

MeO

O MeO

O

MeO

O

MeO

O

HO

O

OH

O

BIM 702

Initial Drug Discovery Approach

The Mannich reaction established the framework for BIIB042 in the first step producing BIM-702, and chiral chromatography was employed to separate the four stereoisomers.

toluene, 110 oCOH

N

CO2Me

F

BIM-702

OH

CO2Me

NH

OHC

F

+*

RX Heptane 70-75%

diastereomeric salts andenzymatic approacheswere not successful

SMB, 100%

OH

N

CO2Me

F

BIM-752

Formation of First Chiral Center

• Screened against matrix of chiral stationary phases/solvents

- Best method; AD CSP with Hexane/IPA

• Determined optimum process parameters- Yield, %ee

Chiral SMB Approach

Continuous SMB Process

Racemic BIM702

Chiral SMB

90 kg

Continuous SMB Process

Racemic BIM702

Chiral SMB

BIM752

>99.5%ee

90 kg

Continuous SMB Process

Racemic BIM702

Chiral SMB

BIM752Non-Target Enantiomer

>99.5%ee

90 kg

Continuous SMB Process

Racemic BIM702

Chiral SMB

BIM752Non-Target Enantiomer

Racemization

>99.5%ee

90 kg

Continuous SMB Process

Racemic BIM702

Chiral SMB

BIM752Non-Target Enantiomer

Racemization

>99.5%ee

90 kg

Lab Scale SMB

Second Chiral Center

>95% ee via catalytic hydrogenation (Ru)

N

CO2H

CF3

F

Ru(BINAP), H2

40 atmenantioselective

*

*N

CO2Me

F

BIM-757

CF3

N

CO2H

F

BIM-795

*

CF3

BIIB042

Sodiumtrimethylsilonate

*

• Development of Armodafinil

• Cephalon (Teva)

2) Stage-Appropriate Technology

S

O O

NH2

Stage-Appropriate Technology

• Modafinil (Provigil)– Approved for treatment of apnea, narcolepsy, shift work disorder– Racemic API

• Armodafinil (Nuvigil)

– (R)-Enantiomer– Second generation therapy

S

O O

NH2

Pre-Clinical Phase

aq. NaOHaq. HCl, acetone

Na2CO3, Me2SO4 aq. acetoneNH3, MeOH

DMSAM ModafinilModafinic Acid

- Modafinic Acid was the best candidate for classical resolution

- Easily converted to R-Modafinil

• 85 kgs prepared via crystallization- ~98% ee- Conversion to R-Modafinil - Non-ideal system due to

● Product degradation● Cost inputs● High labor component

Pre-Clinical Phase

S

O O

NH2

Clinical Phase

• Chiral HPLC/SMB study on Modafinil– Screened CSPs– HPLC and SMB methods developed

• 60kg of Phase I material produced – Single column HPLC– >99.0%ee

S

O O

NH2HPLC

• 550kg Phase II/III material produced- Chiral SMB- Optical purity >99.2%ee- Chemical purity >99.7%

• Over 10 MT of processed pre-launch via SMB- Process ran on 300mm and 450mm systems- Stable, robust process

Clinical Phase

• Asymmetric Oxidation Results- 75% isolated yield- >99.5% optical purity

• Significantly longer development than chromatography

• Favorable economics

• Launch of Armodafinil was accelerated due to stage-appropriate technologies

Commercial Launch

• Three different methods employed

• Pre-Clinical – Classical Resolution• Clinical Trials – Chiral HPLC/SMB• Commercial Launch – Asymmetric Synthesis

• Result – Speed to Market

Development of Armodafinil

• Chiral Chromatography can offer advantages– Effective from mgs to MTs– Predictable scale factors– Ability to “dial in” desired %ee

Conclusions

• Ampac

• Biogen Idec

• Teva (Cephalon)

• Novasep

Acknowledgement to Our Partners