Post on 15-Apr-2017
NANOPARTICULATE DRUG DELIVERY
SYSTEM
Presented by: Chinchole Pravin Sonu
(M.PHARM 2nd SEM)DEPARTMENT OF PHARMACEUTICS & QUALITY ASSURANCE
R. C. Patel Institute of Pharmaceutical Education and Research, shirpur.
Introduction
ס NANOTECHNOLOGY comprises technological developments on the nanometer scale, usually 0.1 to 100 nm. Nanotechnology, the science of the small. Nano is Greek for dwarf, and nanoscience deals with the study of molecular and atomic particles.
The application of nanotechnology in pharmaceutical field includes formulation of Nanoparticles, Nanosuspension, Nanospheres, Nanocapsules, and Nanoemulsion.
NANOSUSPENSIONS : They are colloidal dispersions of nanosized drug particle that are produced by suitable method and stabilized by suitable stabilizer .
NANOPARTICLES : They are solid colloidal particles sized from 30-100 nm . NANOSPHERES : Polymer matrices in which drug is dissolved or dispersed .
NANOCAPSULES : Consists of polymer wall entrapping an oily core in which the drug is dissolved
HISTORY -Nanoparticles as a drug delivery vehicle were first developed by Spieser and co-workers in the late 1960s. -In early 1970s the cross linked polyacrylamide nanoparticles were produced. -Scheffel et al. developed a process for production of radiolabelled albumin particles for imaging purpose in nuclear medicines. -Widder et al incorporated magnetic particles into the nanoparticles for targeting of these particles by means of magnetic field.
. NANOPARTICLES : Nanoparticles are particles made of natural or
synthetic polymers ranging in size from 50 to 500 nm. They consist of macromolecular materials in which the active principle ( drug or biologically active material ) is dissolved, entrapped, and or to which the active principle is adsorbed or attached.
there are mainly 2 type of nanoparticles NANOPARTICLES
ס Nanospheres are solid core spherical particulates, which
contain drug embedded within the matrix or adsorbed onto the surface.(Matrix type)
Nanocapsules are vesicular system in which drug is essentially encapsulated within the central core surronded by a polymeric sheath.(Reservoir type)
MATRIX type
RESERVIOR type
NANOSPHERES NANOCAPSULES
DEFINITION : SUBNANOSIZED STRUCTURES C
CONTAIN DRUG OR BIOACTIVE SUBS. WITHIN THEM
SIZE RANGE : 5nm – 300 nm
ADVANTAGES:
IMPROVED EFFICACY REDUCED TOXICITY ENHANCED DISTRIBUTION IMPROVED PATIENT COMPLIANCE
EXAMPLE : IN CANCER CHEMOTHERAPY,
CYTOSTATIC DRUGS DAMAGE BOTH MALIGNANT AND NORMAL CELLS ALIKE . BUT NANODRUG DELIVERY SELECTIVELY TARGETS MALIGNANT TUMOR ONLY…..
TYPES OF NANOPARTICLES :
1. POLYMERIC NANOPARTICLE2. SOLID LIPID NANOPARTICLE3. NANOSUSPENSION4. POLYMERIC MICELLES5. CERAMIC NANOPARTICLES6. LIPOSOMES7. DENDRIMERS8. MAGNETIC NANOPARTICLES9. NANOSHELLS COATED WITH GOLD10. NANOWIRES11. NANOPORES12. QUANTUM DOTS13. FERROFLUIDS
1. POLYMERIC NANOPARTICLES
SOLID COLLOIDAL PARTICLES SIZE : 10 nm – 1000 nm
NANOCAPSULES : DRUG IS IN CAVITY SURROUNDED BY UNIQUE POLYMER MEMBRANE
NANOSPHERES : MATRIX SYSTEM IN C DRUG IS DISPERSED
NANOCAPSULE NANOSPHERE
Advantages:Small size → Easy penetration
through capillaries → Drug accumulation at target site
Use of biodegradable material for preparation → Sustained drug release
Application :• Controlled & targetted drug
delivery
2. SOLID LIPID NANOPARTICLES Colloidal Carrier System
Size : 100 – 500 nm Delivery medium for lipophilic drugs
ADVANTAGES : Good Biocompatibility, low toxicity &
stability
3. NANOSUSPENSION Good for poorly soluble drugs Size : 200 – 600 nm Drug powder + surfactant in high
pressure homogenisation → Nanoparticles
4. POLYMERIC MICELLES• Miceller systems for systemic delivery of water-insoluble drugs• Amphiphilic copolymer self associate to form micelles in water.• Small size < 100 nm in diameter leads to avoiding of renal excretion and RES• Small size also leads to endothelial cell permeability • Accumulate greatly in tumor cells than in normal
ADVANTAGES : Better thermodynamic stability in
physiological solution Stable & prolonged systemic
circulation time Rapid invivo dissociation is prevented
5. CERAMIC NANOPARTICLES
SIZE : < 50 nm
Ceramic particles with entraped biomolecules
ADVANTAGES :Easy preparation process as
similar to sol-gel processNo swelling or porosity changes
with pHProtection for doped molecules
(enzymes , drugs )against denaturation caused by pH & temp.
Compatible with biological systems
Easy conjugation to variety of monoclonal antibodies to target desired sites invivo
6. LIPOSOMES Small artificial spherical shape
vesicles Prepared from natural non toxic
phospholiids and cholesterol
Classification : Based on size & no. of bilayers ::1. Small unilamellar vesicles [ SUV ] Size : 25-50 nm in diameter2. Large unilamellar vesicles [ LUV ]3. Multilamellar vesicles [ MLV ] Several lipid layers separated by
layer of aq. solution• Drugs in liposomes reduce systemic
toxicity & prevent early degradation• Liposome surface can be modified
by attaching PEG to bilayer to enhance circulation time in blood.
7. Dendrimers Tree like molecules with defined
cavities
8. Magnetic Nanoparticles• Powerful versatile diagnostic tool in
medicine Use :1. To label sp molecule , cell population
or microorganisms by binding to suitable Ab
2. As contrast agents in MRI3. As a drug delivery mediumMagnetic immunoassay : Magnetic field generated by
magnetically labelled targets is detected by a sensitive magnetometer
Composition : Iron oxide [magnetite Fe203 or
maghemite ] coated with polymer such as dextran.
Commercial products :1. Lumiren ( silicon coated iron oxide) Diameter : 300 nm2. Endorem ( dextran coated
magnetite) Diameter : 150 nm
9. NANOSHELLS COATED WITH GOLD
Infrared optical activity combine with properties of gold colloid
Consist of :1. Dielectric core ( gold sulfide or
silica or silica ) 2. Metal shell (gold)
Particle < 75 nm diameter absorb & others scatter the incidence light
Surface properties of gold nanoshells = gold colloid.
Use : Destroy breast cancer cells Antibodies to breast cancer
can be directly attached to gold nanoshells
Nanoshells strongly absorb infrared light while normal tissue is transparent to it
Nanoshell-antibody complex binds only to cancer cells
Infrared laser heats up the nanoshells and thus cancer cells are destroyed.
10. Nanowires & Carbon nanotubes Linear nanostructures made from
metals, semiconductors or carbon . Modifications : Single- or multi-walled, Filled or surface
modified Use : Fillers for nanocomposites for
material with sp properties
11. NANOPORES
Eg : Aerogel produced by sol-gel chemistry
Applications :1. Catalysis2. Thermal insulation3. Electrode material4. Environment filters5. Controlled release drug carriers
12. Quantum Dots Highly light absorbing luminescent
semiconductor nanoparticles Size : 2-8 nm in diameter Luminescence properties of
semiconductor is sensitive to local envrm and nanocrystal surface prepartion.
CdSe-CdS core shell Range : 550nm to 630 nm InP & InAs Range : Near infrared region
Fuctionalisation with mercaptoacetic acid or thin silica layer makes it water soluble
Covalent attachment of proteins to mercaptoacetic acid makes it biocompatible
Binding to cell surface, insertion in cell surface & binding to cell nucleii is possible due to conjugation of nanoparticle with targeting protein
13. Ferrofluids Colloidal solutions of iron oxide
magnetic nanoparticle covered by polymer layer coated with affinity molecules s/a Ab
Size: 25-100 nm radius Hence they behave as a solution
rather than suspension
ADVANTAGES OF NANOSIZING OF DRUGS
Increase surface area Enhances solubility Increase rate of dissolution Increase oral bioavailability More rapid onset of therapeutic
action Decreased dose Decreased patient-to-patient
variability Target specificity Limited side effects
Limitations Expensive therapy Excess use of PVA as a detergent
issues with toxicity Limited targeting abilities Discontinuation of therapy is not
possible Conclusion Polymeric systems have great
potential in drug delivery application Still none of this systems is applied in
practice to patients- FDA approval requires extensive toxicity investigations
Approaches for the preparation
Methods of preparation 1) Amphiphilic macromolecule cross-linking a) Heat cross-linking. b) Chemical cross-linking.
2) Polymerization based methodsa) Polymerization of monomers in situ.b) Emulsion (micellar) polymerization.c) Dispersion polymerization.d) Interfacial condensation polymerization.e) Interfacial complexation.
3) Polymer precipitation methods a) Solvent extraction/Evaporation. b) Solvent displacement (Nanoprecipitation). c) Salting out.
PREPARATION METHODS OF NANOPARTICLES
Proteins Gelatin Albumin Lectins Legumin Vicilin
polysaccharides Alginate Dextran Chitosan Agarose Pullulan
(Polymers for nanoparticles)
Various synthetic polymers used for prepration of nanoparticles
Prepolymerised Poly(e-caprolactone) Polylactic acid Poly(lactide-co-
glycolide) Polystyrene
Polymerised in process Poly(isobutylcynoacrylate) Poly(butylcynoacrylate) Poly(hexylcynoacrylate) Polymethylmethacrylate
Polymers used for preparation of nanoparticles& nanocapsules
Polymer use Technique Candidate drugHydrophilicAlbumin, gelatin
Heat denaturation & cross linking in w/o emulsionDesolvation &cross linking in aqueous medium
Hydrophilic
Hydrophilic & protein affinity
Alginate,chitosan Cross linking in aq. medium Hydrophilic & protein affinity
Dextran Polymer precipitation in an organic solvent
Hydrophilic
HydrophobicPoly(alkylcyanoacrylates)
Emulsion polymerizationInterfacial/polymerization
HydrophilicHydrophobic
PolyestersPoly(lactic acid,poly(lactide-co-glycolide)poly(€-caprolactone)
Solvent extraction-evaporationSolvent displacementSalting out
Hydrophilic ,HydrophobicSoluble in polar solventSoluble in polar solvent
Method of preparation for nanoparticles
Amphillic macromolecules that undergo a crosslinking reaction during preparation of nanospheres
Monomers that polymerize during formation of nanospheres
Hydrophobic polymers which are initially dissolved in organic solvents & then precipitated under controlled conditions to produce nanospheres
Nanoparticles preparation by cross linking of amphiphilic macromolecules
It can be prepared from amphiphilic macromolecules, proteins & polysaccharides which have affinity for aq.&lipid solvents.
The tech.of their preparation involves the aggregation of amphiphiles followed by further stabilization either by heat denaturation or chemical cross linking.
Cross linking in w/o emulsion1. The method involves the emulsification of bovine serum albumin/human
serum albumin or protein aq. solution in oil using high pressure homogenization or high frequency sonication
2. The w/o emulsion so formed is poured into preheated oil. The suspension in preheated oil maintained above 1000C is held stirred for time in order to denature & aggregate the protein contents of aq. pool completely & to evaporate water
3. The particles are finally washed with organic solvent to remove any oil traces & collected by centrifugation
4. The main factors are emulsification energy & temperature (used for denaturation & aggregation
Phase separation in aqueous medium (desolvation)
The protein or polysaccharide from an aq. phase can be desolvated by PH change or temp change or by adding counter ions. Cross linking may be affected simultaneously or next to the desolvation step
Steps are protein dissolution, protein aggregation & protein deaggregation
Solvent competing agent ,sodium sulphate is mainly used as a desolvating agent while alcohol are added as desolvating or deaggregating agent
Addition can be optimized turbidometrically using Nephelometer.
Aqueous phase (Protein aq.solution)
Protein aggregates (coacervates)
Desolvation (solvent competing agent)
Protein colloidal dispersion
Nanoparticle suspension (external aq. Phase)
Crosslinking(aldehyde)
Resolvation(alcohol)
Nanoparticle preparation by desolvation in an aq. medium technique
PH induced aggregation
Gelatin & Tween 20 were dissolved in aq. phase & PH was adjusted to optimum value. Solutions were heated ,then quenching at 4oC for 24h.The leads to colloidal dispersion of aggregated gelatin. The aggregates were finally cross linked using glutaraldehyde.The size of nanospheres were of 200 nm. The ideal PH range is 5.5-6.5.
Counter ion induced aggregation
Separation of protein phase may occur by the presence of counter ions in the aqueous medium.
The aggregation can be propagated by adding counters ions followed by rigidization step.
Chitosan nanospheres can be prepared by adding tripolyphosphate to the medium.
Alginate nanoparticles can be prepared by gelation with calcium ions
Nanoparticles prepared by polymerization methods
The polymers used for nanospheres preparation include poly (methylmethacrylate) poly(acrylamide)poly(butyl cyanoacrylate).
The different methods using in situ polymerization tech. are
Methods in which the monomer to be polymerised is emulsified in a non solvent phase or (emulsion polymerization)
Methods in which the monomer is dissolved in a solvent that is non solvent for the resulting polymer (Dispersion polymerization)
In EP method the monomer is dissolved in an internal phase while in case of DP it is taken in dispersed phase
In both cases after polymerization polymer tends to be insoluble in internal phase & results into suspension of nanospheres
Emulsion polymerization Micellar polymerization
The mechanism involved are micellar nucleation & polymerization & homogenous nucleation & polymerization
The first includes swollen monomer micelles as the site of nucleation & polymerization.
The monomer is emulsified in the non solvent phase with the help of
surfactant molecules. The process leads to formation of monomer swollen micelles which has
size in nanometric range.
The polymerization reaction proceeds through nucleation & propogation in the presence of chemical or physical initiator
Homogeneous polymerization Monomer is sufficiently soluble in the continuous outer phase
Formation of primary chains (oligomers)
At certain length oligomers precipitate & forms primary particles which are stabilized by surfactant
Addition of monomer input or fusion of primary particles forms nanoparticles
Water soluble drugs may be associated with PACA nanoparticles either by dissolving the drug in the aqueous polymerization medium or by incubating the blank nanospheres with an aq. solution of drug
Drug molecules may be entrapped within the polymer matrix & are also adsorbed onto the surface of nanoparticles
Drug molecules may be physically adsorbed on the surface
Dispersion polymerization
In emulsion polymerization monomer is emulsified in an immiscible phase using surfactant.In case of dispersion polymerization monomer is dissolved in an aqueous medium which acts as precipitant for polymer
The monomer is introduced into the dispersion medium. Polymerization is initiated by adding a catalyst & proceeds with nucleation phase followed by growth phase.
Inverse emulsification polymerization mechanism
Emulsion polymerization process
The nucleation is directly induced in the aqueous monomer solution & the presence of stabilizer or surfactant is not required
The acrylamide or methyl methacrylate monomer is dissolved in aqueous phase & polymerized by gamma irradiation
By chemical initiation (ammonium or potassium peroxodisulphate) combined with heating to temp. above 65 0C
PMMA nanoparticles can be prepared by gamma irradiation in the presence of antigenic material
e.g. influenza virion, influenza sub unit antigen, bovine serum albumin, HIV-1 & HIV-2 antigens
Interfacial polymerization
The preformed polymer phase is finally transformed to an embryonic sheath.
The polymer & drug are dissolved in a volatile solvent. The solution is is poured into a non solvent for both polymer & core phase.
The polymer phase is separated as as a coacervate phase at o/w
interface. The mixture turns milky due to formation of nanocapsules.
This method is used for proteins, enzymes, antibodies, & cells
Interfacial polymeric condensation of 2,2-bis-(4hydroxyphenyl) propane & sebacoyl chloride
The size of nanocapsules ranges from 30-300nm
Nanoparticle preparation using emulsion solvent evaporation method
Hydrophobic polymer & or hydrophobic drug is dissolved in a organic solvent followed by its dispersion in a continuous aq. Phase in which the polymer is insoluble. External phase contains stabilizer.
Depending upon solvent miscibility tech.may called as solvent extraction or evaporation method
The polymer precipitation is done by
Increasing the solubility of organic solvent in the external medium by adding an alcohol (isopropanol)
By incorporating water into ultraemulsion(to extract solvent)
By evaporation of solvent at room temp. by using vacuum
Using an organic solvent which is completely soluble in the continuous aq.phase(acetone)nanoprecipitation
Solvent extraction method
This method involves the preparation of o/w emulsion
The subsequent removal of solvent or the addition of water to the system so as to affect diffusion of solvent to external phase (emulsification diffusion method)
The solvent used for polymer is poorly miscible with dispersion phase & thus diffuses & evaporates out slowly on continual stirring
Dispersion medium miscible polymer solvent (alcohol & acetone instantaneously diffuses into the aq. phase & polymer precipitates as tiny nanospheres
Solvent evaporation method Solvent evaporation done by altering pressure or high speed
homogenization. E.g. Testosterone, Indomethacin.
64
Emulsification
Aqueous phase Distilled water
Surfactant
Solvent evaporation
nanospheres
O/W emulsion
Organic phase Chlorinated Solvent
Polymer
Emulsification solvent evaporation method
Solvent displacement method
Salting out
Solvent displacement method
It is based on interfacial deposition of a polymer following displacement of a semi polar solvent miscible with water from a lipophilic solution
The organic solvent diffuses instantaneously to the external aq. Phase inducing immediate polymer precipitation because of complete miscibility of both the phases
If drug is highly hydrophilic it diffuses out into the external aq. phase while if drug is hydrophobic it precipitates in aq. medium as nanocrystals
Solvent displacement method
Review on Nanoparticulate carriersNanocarrier system
Preparation method
Polymer/ Lipid based system
Drug Advantage/ Application
Polymeric Solvent evaporation PEG with PEO coating
Protein Fast drug release for 4 hours
nanoparticles Solvent evaporation PLGA Dexamethasone Sustain release for 10 days
nanoprecipitation PLGA Docetaxel Minimized cytotoxicity
Solvent evaporation PLGA-co-PCL Diphtheria toxoid Improved drug uptake
Solid lipid Hot homogenization Stearic acid in 0.1% poloxamer 188
Insulin 80% entrapment efficiency
nanoparticles Emulsion solvent diffusion
Stearic acid in 1% wt/vol aq.PVA
Antitubercular drug Sustained plasma level over 8 day
Magnetic Bottom up fabrication Metallic Fe with activated carbon
Cancer treatment Parenteral administration
nanoparticles Co-precipitation followed by separation
Dextran coated iron oxide
Cancer treatment 74% to 95% drug entrapment
Contd.Nanocarrier system
Preparation method
Polymer/lipid based system
Drug Advantage/ Application
Quantum dots Modified one pot method
Positively charged CdTe QD’s
Gene delivery Imaging agents
Colloidal nanosuspension
CdSe-ZnS core shell nanocrystals of QD’s
In-vitro imaging 10% to 20% higher gene silencing activity
Polymeric Co-polymerization Pluronic-PPA micelles
Solid tumor treatment
Increased sol. of hydrophobic drugs
micelles Co-solventevaporation
PEO-PPO-PEO Solid tumor treatment
Minimized cytotoxicity
Nanosized
Colloidal liposome's
Dehydration-Rehydration methods
DOPE-glycol chitosan liposome
Nasal DNA vaccine 53% entrapment efficiency
Suspension and subsequent extrusion
PC/Chol/PEGDSPE Gene delivery Prolonged plasma circulation(24hr)
Schematic diagram for the development of targeted nanoparticles
Using a platform technology we first generate an activated nanoparticle. In a second reaction the targeting agent (antibodies) is conjugated to the outer surface of the nanoparticle with the help of Linkers or Spacers.
• The nanoparticle now produced is ready for its specific target.
MODE OF ACTION
The targeted nanoparticle finds the specific cellular target.
The nanoparticle binds to the surface of the cell
If the target is internalized (i.e. folate receptors) the nanoparticle
is carried to the intracellular environment
If the target is not internalized (i.e. annexin A2) the delivery
system has been engineered to release the nanoparticle at the
surface of the cell allowing for endocytosis to occur.
1) EXHIBIT HIGHER INTRACELLULAR UPTAKE .
2) CAN PENETRATE THE SUBMUCOSAL LAYERS WHILE THE MICROCARRIERS ARE PREDOMINANTLY LOCALIZED ON THE EPITHELIAL LINING .
3) CAN BE ADMINISTERED INTO SYSTEMIC CIRCULATION WITHOUT THE PROBLEMS OF PARTICLE AGGREGATION OR BLOCKAGE OF FINE BLOOD CAPILLARIES . RESTENOSIS
4) THE DEVELOPMENT OF TARGETED DELIVERY IS FIRMLY BUILT ON EXTENSIVE EXPERIENCE IN PHARMACO-CHEMISTRY, PHARMACOLOGY, TOXICOLOGY AND NOWADAYS IS BEING PURSUED AS A MULTI- AND INTERDISCIPLINARY EFFORT .
5) USED FOR SITE SPECIFIC TARGETTING IN VARIOUS CANCER CONDITIONS,GENE THERAPY, .
The potential of Nanocarriers as Drug Delivery Systems.
Stimuli that can be utilized to control the behavior and properties of drug delivery systems.
Stimuli Site Stimuli origin
pH
Temperature
Temperature
Magnetic field
Ultrasound
Internal
Internal
External
External
External
Decreased pH in pathological areas, such as tumors, infarcts, and inflammations, because of hypoxia and massive cell death.
hyperthermia associated with inflammation.
Can be caused inside target tissues by locally applied ultrasound or by locally applied high frequency causing the oscillation of target-accumulated magneto-sensitive nanoparticles with heat release.
Magnetic field of different gradients and profiles applied to the body can concentrate magneto-sensitive DDS in required areas.
Sonication can be applied to the body to get a diagnostic signal from echogenic contrast agents and can also facilitate DDS penetration into cells and drug/gene release from ultrasound-sensitive DDS.
CHALLENGES
Prevention of drug from biological degradation
Effective Targeting
Patient Compliance
Cost effectiveness
Product life extension
20/03/2008 Dept. of Pharmaceutics 75
Where all the action is the
Block copolymer micelles for gene therapy
Transfection of plasmid DNA using diblock copolymer.
DNA is released inside the cytosol and appears in the nucleus to express a desired protein.
PHARMACEUTICAL ASPECTS OF NANOPARTICLES
The important process parameters performed are Purification, Freeze drying, Sterilization.
1) Purification of nanoparticles:-Toxic impurities includes organic solvents, residual monomers, polymerization initiators, electrolytes, stabilizers & large polymer aggregates. Most commonly used method is gel filtration, dialysis & ultra centrifugation.
But a new methodology called as cross flow filtration method is used.
2) Freeze drying of nanoparticles It includes freezing of nanoparticle suspension & sublimation of water to produce
free flowing powder. Advantages area) Prevention from degradation and/or solubilization of the polymer.b) Prevention from drug leakage, drug desorption, drug degradation.c) Readily dispersible in water without modifications in their physicochemical
properties.
Nanocapsules containing oily core may be processed in the presence of mono or disaccharides (glucose or sucrose).
3) Sterilization of Nanoparticles
Nanoparticles for parenteral use should be sterilized to be pyrogen free before animal or human use.
Sterilization in nanoparticles is achieved by using aseptic tech.throughout their preparation & processing & formulation & by sterilizing treatments like autoclaving or gamma- irradiation.
Characterization of nanoparticlesParameter Characterization method
Particle size & size distribution Photon correlation spectroscopy,Transmission electron microscopy,Scanning Electron Microscopy,Atomic force microscopy.
Charge determination Laser doppler anemometry, Zeta potentiometer.
Surface hydrophobicity Water contact angle measurements, rose bengal binding X-ray photoelectron spectroscopy
Chemical analysis of surface Static secondary ion mass spectrometry, Sorptometer
Carrier-drug interaction Differential scanning calorimetry
Nanoparticle dispersion stability Critical flocculation temp (CFT)
Release profile In vitro release characteristic under physiologic & sink conditions
Drug stability Bioassay of drug extracted from nanoparticles,Chemical analysis of drug
1) Size & morphology EM(SEM & TEM) are widely used for determining particle size & its
distribution. Freeze fracturing of particles allows for morphological determination of
inner structure of particles. TEM permits differentiation among nanocapsules, nanoparticles, &
emulsion droplets Atomic force microscopy (AFM) images can be obtained in an
aq.medium hence used for investigation of nanoparticle behavior in biological environment.
2) Specific surface:- Is determined with the help of Sorptometer. A = 6/ density x D3) Surface charge & electrophoretic mobility:-The nature & intensity of
surface charge determines their interaction with biological environment as well as with bioactive compounds.It is determined by measuring the particle velocity in an electric field. (Laser doppler anemometry)
The surface charge of colloidal particles is measured as electrophoretic mobility which is determined in phosphate saline buffer & human serum
4) Surface hydrophobicity:-influences in interaction with biological environment ( Protein particles & cell adhesion).
It is determined by two phase partition,contact angle measurements, adsorption of hydrophobic fluorescent or radiolabelled probes.
X-ray photoelectron spectroscopy permits the identification of specific chemical groups on the surface of nanoparticles.
4) Density:-The density of nanoparticles is determined with helium or air using a gas Pycnometer
5) Molecular weight measurement of nanoparticles:- Molecular weight of the polymer & its distribution in the matrix can be evaluated by gel permeation chromatography using a refractive index detector.
6) Nanoparticle recovery & drug incorporation efficiency:-Nanoparticle yield can be calculated as
nanoparticles recovery(%) = Conc. of drug in nanoparticles *100 conc of nanoparticles recovered
7) Drug incorporation efficiency or drug content:-
Drug content(% w/w) = Conc of drug in nanoparticles *100
conc of nanoparticles recovered
8) In vitro release:-In vitro release profile can be determined using standard dialysis, diffusion cell or modified ultrafiltration technique
IN VIVO FATE & BIODISTRIBUTION OF NANOPARTICLES
The plasma proteins (opsonins) adsorb on to the surface of colloidal carriers & render particles recognizable to RES.
Phagocytosis of particulates by elements of RES( liver, spleen, bone marrow), liver( Kupffer cells )is regulated by opsonins & dysopsonins (IgA).
SURFACE ENGINEERING OF NANOPARTICLES
1) Stearic stabilized(stealth) nanoparticles2) Biomimetic nanoparticles3) Antibody coated nanoparticles4) Magnetically guided nanoparticles5) Bioadhesive nanoparticles
Methods of drug delivery
APPLICATIONS OF NANOPARTICLES1) Oral Drug Delivery. Nanosizing of drug lead to dramatic increase in their oral absorption and subsequent bioavailability because of- Increase surface area. Increase saturation solubility. Looareesuwan et al 1999, Atovaquinone an antibiotic indicated for Pneumnocystis carinii showed 2.5 fold increase in oral bioavailability used in the treatment of PCP. Other drugs studied include Danazol, Amphotericin B (kayser et al 2003). 2) Parenteral Drug Delivery. Taxanes has been found useful in the treatment of various cancers .As Taxanes are insoluble in water, TAXOL Nanoemulsion containing Paclitaxel with polyethoxylated castor oil in ethanol was prepared.
A vitamin E-based Nanoemulsion of Paclitaxel (TOCOSOL paclitaxel) was developed by SONUS Pharmaceuticals. It is a Cremophor-free formulation of paclitaxel, a ready-to-use injectable product that incorporates high drug loading (8–10 mg/ml) . Based on the data to date, TOCOSOL paclitaxel shows greater tumor accumulation than Taxol® and antitumor efficacy. TOCOSOL paclitaxel nanodroplets manufactured by proprietary high shearing homogenization have a mean droplet diameter in the range of 40–80 nm, are stable and neutrally charged, which allows for diffusion into the tumor interstitium.
REF; Advances in lipid nanodispersions for parenteral drug delivery and targeting by Panayiotis P. Constantinides, Mahesh V. Chaubal, Robert Shorr. Biopharmaceutical and Drug Delivery Consulting, LLC, Gurnee, IL, USA; Baxter Healthcare, Round Lake, IL, USA.
3) Ocular Drug Delivery.Biodegradable as well as water soluble polymer possessing ocular tolerability can be used to sustain the release of the drug.
(Bucolo et al. 2002) successfully formulated FLURBIPROFEN & IBUFROFEN Nanosuspension using acrylate polymers such as Eudragit RS 100 & Eudragit RL 100.
4) Pulmonary drug delivery.Increase adhesiveness of drug to mucosal surface, prolongs the residence time of drug at absorption site.
It offers quick onset of action initially and then control release of active moiety which is required by most pulmonary disorders.
Budesonide is poorly water soluble corticosteroid has been successfully formulated as a Nanosuspension for pulmonary drug delivery.
5) Targeted drug delivery.This system has showed tremendous potential in target drug delivery, especially to brain.
Successful targeting of peptide Dalargin to brain by employing surface modified poly (isobutyl cyanoacrylate) Nanoparticle has been the major achievement in target drug delivery.
Natural targeting of RES by nanosuspension has been already described.Stealth nanoparticles are also produce to avoid RES.
Mucoadhesive bupravaquone nanosuspension reveled 10 fold reductions in infectivity score of Cryptosporidium parvum.
Brain targetting BBB is one of the hurdles for the antineoplastics, antibiotics
and neuroleptic agents. Drugs like hexapeptide dalargin, tubocurarine ,doxorubicin
have been targetted by the following approaches1) Higher concentration gradient across the BBB,2) Solubilization of endothelial cell membrane by surfactants,3) Loosening of the tight junction between endothelial cells,4) Endocytosis of nanoparticles and5) Transcytosis of the nanoparticles.
Kreuter and co-workers 1995,reported the transport of the hexapeptide dalargin across the blood-brain-barrier using poly(butylcyanoacrylate) nanoparticles, which were coated with polysorbate80.
Enhanced Permeability and Retention (EPR) effect-Nanoparticle entry and accumulation in tumors PEGylated particles, in the desired size range, leaks out of the microvasculature and accumulates into the tumor site.-Insufficient lymphatic drainage favors retention of PEGylated Particles within the tumor site.
Various therapeutic applications of nanoparticles /nanocapsules
Application Material Purpose
Cancer therapy Poly(alkylcyanoacrylate)nanoparticleswith anticancer agents,oligonucleotides
Targeting,reduced toxicity, enhanced uptake of antitumour agents, improved in vivo & in vitro stability
Intracellular targeting
Poly(alkylcyanoacrylate)Polyester nanoparticles with anti parasitic or antiviral agents
Target RES for intracellular interactions
Prolonged systemic circulation
Polyesters with adsorbed polyethylene glycols or pluronics
Prolong systemic drug effect,avoid uptake by RES
Vaccine adjuvant Poly (methylmetghacrylate)nanoparticles with vaccines(oral & IM injection)
Enhances immune response
Application Material PurposePeroral absorption
Poly(methylmetghacrylate)nanoparticles with proteins & therap.agents
Enhanced bioavailability &protection from GI enzymes
Ocular delivery Poly(alkylcyanoacrylate)with steroids,antiinflammatory agents,antibacterial agents for glaucoma
Improved retention of drugs/reduced wash out
DNA delivery DNA gelatin nanoparticles, DNA chitosan nanoparticles,
Enhanced delivery & higher expression levels
Oligonucleotide delivery
Alginate nanoparticles, poly(D,L)lactic acid nanoparticles
Enhanced delivery of oligonucleotide
Other applications
Poly(alkylcyanoacrylate)nanoparticles with peptidesFor transdermal applicationNanooparticles with radioactive or contrast agentsCopolymerized peptide nanoparticles of n-butyl cyanoacrylate & activated peptides
Crosses blood brain barrier
Improved absorption & permeationEnzyme immunoassays,Radioimaging
Oral delivery of peptides
The six major challenge areas of emphasis1. Prevention and Control of Cancer Developing nanoscale devices that can deliver
cancer prevention agents and anticancer vaccines using nanoscale delivery vehicles.
2. Early Detection and Proteomics Creating implantable molecular sensors that can
detect cancer-associated biomarkers(MEMS).3. Imaging Diagnostics
Designing “smart” injectable,targeted contrast agents that improve the resolution of cancer to the single cell level. i.e. Quantum Dots.
.
4. Multifunctional Therapeutics Developing nanoscale devices that integrate
diagnostic and therapeutic functions.5. Quality of Life Enhancement in Cancer Care Designing nanoscale devices that can optimally
deliver medications for treating side effects due to chronic anticancer therapy, including pain, nausea, loss of appetite, depression,difficulty in breathing and emesis.
6. Interdisciplinary Training Coordinating efforts to provide cross-training in
molecular and systems biology to nanotechnology engineers and in nanotechnology to cancer researchers.
Recent advances An emerging, interdisciplinary science
Integrates chemistry, physics, biology, materials engineering, earth science, and computer science.
The power to collect data and manipulate particles at such a tiny scale will lead toNew areas of research and technology design Better understanding of matter and interactionsNew ways to tackle important problems in healthcare, energy,
the environment, and technologyA most practical applications now, but problems in preparing at
large level.Example : Clottocyte, Respirocyte
Artificial platelets (Clottocyte)An artificial mechanical platelet appears to halt bleeding 100-1000 times
faster than natural hemostasis. A single clottocyte, upon reliably detecting a blood vessel break, can rapidly communicate this fact to its neighbors, immediately triggering a progressive controlled mesh-release cascade.
Respirocyte The artificial red bloodcellor "respirocyte”
Proposed here is a bloodborne spherical 1-microndiamondoid 1000-atmpressure vessel with active pumping powered by endogenous serum glucose, able to deliver236 times more oxygen to the tissues per unit volume than natural red cells and to manage carbonic acidity.
An onboard nanocomputer and numerous chemical and pressure sensors enable complex device behaviors remotely reprogrammable by
the physician via externally applied acoustic signals.
Primary applications will include:1) Transfusable blood substituent's.2) Partial treatment for anemia,3) Perinatal/neonatal and lung disorders;4) Tumor therapies and diagnostics;5) Artificial breathing and6) Prevention of asphyxia.
REFERENCES Swarbrick J, Boylan J. Encyclopedia of pharmaceutical technology. 2nd ed.;
Marcel Dekker, New York, 2002, pp : 443.
Targetted and controlled drug delivery, Novel carrier systems; S.P Vyas and R.K.Khar , CBS publishers and distributors, New Delhi, pg no : 331-385.
Pharmaceutical dosage form and drug delivery; Ram I. Mahato, CRC press; pg no : 258-260.
Advances in controlled and novel drug delivery ; Jain N.K. ,CBS publishers and distributors, New Delhi, pg no : 408-426.
www. nanoproject.org
www.nanomanufacturing.eu
NANOPARTICLES & NANOTECHNOLOGY by Dr Paranjothy Kanni*, Health Administrator , Vol : XX, Number 1&2, pg no : 26-28.
1) Kreuter J, Ramge P, Petrov V, Hamm S, Gelperina SE, Engelhardt B, Alyautdin R, von Briesen H, Begley DJ. Direct evidence that polysorbate-80-coated poly(butylcyanoacrylate) nanoparticles deliver drugs to the CNS via specific mechanisms requiring prior binding of drug to the nanoparticles .Journal of Pharmaceutical science 2003; pg no. 409-16.
2) Chen Y, Dalwadi G, Benson H. Drug delivery across the blood-brain barrier. Current Drug Delivery 2004; vol .1, pg no.361-376.
3) Binding and release of drugs into and from thermo sensitive poly(N-vinyl caprolactam) nanoparticles.
* Henna Vihola , Antti Laukkanen , Jouni Hirvonen , Heikki Tenhu . Division of Pharmaceutical Technology, Viikki Drug Discovery Technology Center,
University of Helsinki, PB 56, FIN-00014, Helsinki, Finland. Journal of pharmaceutical science.
4) Colloidal Nanocarriers: a review on formulation technology, types and applications toward targeted drug delivery.
B. Mishra , PhD; Bhavesh B. Patel; Sanjay Tiwari. Department of Pharmaceutics, Institute of Technology, Banaras Hindu University,
Varanasi, India.
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