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POLYMER SCIENCE

-:PRESENTED BY:-PRADIP GHORI

M.PHARM I YEARDEPARTMENT OF PHARMACEUTICS

M.M.C.P

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CONTENTS:

• INTRODUCTION• IDEAL CHARACTERISTICS• POLYMER CLASSIFICATION • APPLICATIONS

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INTRODUCTION:The word is derived from Greek word ‘poly’ means ‘many’ ‘meros’ means ‘parts’ The basic unit is known as monomerDefinition:Polymer is composed molecules with largemolecular mass, composed of repeating structural units or monomers connected by covalent chemical bonds. The process used for this is known as ‘POLYMERIZATION’

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Polymerization Polymerization

the use of heat, pressure or a chemical the use of heat, pressure or a chemical catalyst to link monomer material into catalyst to link monomer material into polymer chains.polymer chains.

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IDEAL CHARACTERISTICS:• Should be Inert • Should be compatible with environment.• Should be Nontoxic• Easy and inexpensive to fabricate the dosage form.• Should have good mechanical strength.• Should be inexpensive.• Readily unavailable.

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Factors that affects Physical propertiesof polymer: 1. Degree of polymerization 2. Molar mass distribution 3. Crystallinity 4. Branching 5. Stereo regularity: - isoelecric arrangement of function group on backbone of carbon skeleton. 6. Strength may vary with temperature and formulation

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CLASSIFICATION

1.Simple classification2.Based on their interaction with water3.Based upon linkage 4.Based on method of polymerization5.Based on polymerization mechanisms6.Based on composition.

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Simple classification of polymer: POLYMERS

NATURAL SYNTHETIC

Biodegradable Non biodegradable

glycosides and its polymers

polyanhydrides Acrolein, epoxy polymersProteinsCarbohydratesNucleic acids

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2. Based on their interaction with water

POLYMER

Non Hydro gels Soluble Biodegradable biodegradable polymer -Natural -PVC -PVP -HPMC e.g.. Albumin -PVA -PEG Gelatin

-Synthetic e.g.. PLA

PGA

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3.Based upon linkage: A. Thermoplastics: e.g. PVA, PVC

a.Linear polymer: A'-(A)X-2-A'' where x = degree of polymerization A' & A''=terminal groupsb. Branched polymers: A'-(A)n-y- (A)n'-y-

(A)n (A)n

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B. Thermostatic:

c. Cross linked polymers e.g. epoxy glue, styrene monomer

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4.Based on method of polymerization: A. Addition polymer: Here the repeating units of the polymer have the same molecular formula. They are prepared by polymerization of monomers. B. Condensation polymer: Here polymer are formed by successive reaction of functional group.

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5. Based on polymerization mechanisms:

1.Chain polymerized polymer: involves initiation, propagation, and

termination. 2.Step growth polymerized polymer:

no discrete initiation, propagation takes place but instead involves sp. Reaction b/w

functional group.

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addition Condensation

Example Polystyrene Nylon

Empirical formula No change from monomer.

Changes as byproduct (often water) is given off.

How grows One monomer at a time

Monomer + dimer, hexamer + octadecamer, etc.

Molecular weight Wide range: can be very high

Low (except biopolymers)

Synonym Chain growth polymerization

Step growth polymerization

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Addition: one monomer at a timeAlso called chain growth.

Condensation: anything goes! Also called step growth.

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6. Based on composition:

A. Homopolymer:e.g. Polyethylene, polystyrenelike -A-A-A-A-

B. Copolymer: e.g. Silicone, Ethyl celluloselike -A-B-A-B-A-B-

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7.Biopolymers: Nucleic Acids

CH2

O

PO

OH

O

OCH2

O

OH

PO O

OH

OCH2

O

PO O

OH

O

OPO

O

O

CH2

O

PO O

OH

O

OH

OH

N N

O

O

HU

N

N

NN

NH

N N

O

NH2

OH

N

N

NN

O

NH2

A

C

G

Ribose sugar Base

NN

NN

O

OP

O

O

OH

CH2

O

O

OPO

OH

CH2

O

O

OPO

OH

CH2

O

O

OPO

OH

CH2

O

PO O

O

NN

CH3 O

O

H

N

NO

NH

H

N

N

NH

H

NN

O

NH

H

CH3

N

N

NN

NH

O

H

H

NN

NNH

H

NN

O

O

H

NN

O

NH

H

O CH2

O

P OO

OH

O

O CH2

O

P O

OH

O

O CH2

O

P O

OH

O

O

O CH2

O

P O

OH

T

G

A

C

A

C

T

G

3'

5'

5'

3'

.....

......

...

........

.........

.....

........

..

.....

....

17RNA DNA

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Applications of polymer in formulationof controlled drug delivery system:1. ORAL DELIVERY SYSTEM: Here the drug gets released at controlled rate whenadministered orally. For that several mechanisms are Involved.

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Osmotic pressure controlled GI deliver system. Gel diffusion controlled GI delivery system Mucoadhesive GI delivery system

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1.Osmotic Pressure Controlled delivery system: Semi permeable membrane made from biocompatible polymers e.g. cellulose acetate 2. Gel diffusion controlled delivery system: Fabricated from gel forming polymers e.g. CMC. 3. Mucoadhesive drug delivery system: It is capable of producing an adhesion interaction with a biological membrane. e.g. carbopol.

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2.TRANSDERMAL DRUG DELIVERY SYSTEM: Mostly used when the medicaments are applied on topical route. It is easily removable when termination of treatment is needed or else in case of condition of toxicity is seen. e.g. Transdermal patch of scopolamine, nitro glycerin.

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3. OCULAR DRUG DELIVERY SYSTEM:• It allows prolonged contact of drug with corneal surface of eye.• Highly viscous suspension and emulsion are served to have such purpose but these preparations don’t achieve this purpose ata controlled rate.• Many ocular drug delivery formulations developed which continuously release the drug at a controlled rate

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Example of pilocarpine ocusert

The best example is ocular insert/ocusertdeveloped to delivered pilocarpine in the treatment of glaucoma

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4.Other applications: Drug Delivery and the Treatment of Diabetes: Here the polymer will act asBarrier between blood stream and insuline.g. of polymer- N,N-dimethylaminoethylmethacrylate or polyacrylamide.

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Drug delivery of various contraceptives and hormones:e.g. Medroxy progesterone acetate releasing vaginal contraceptive rings.

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Various uses of polymer in pharmaceutical sciences:• Formulation of matrix tablets• Formulation of nanoparticles• Formulation of solid dispersion• In targeted drug delivery system• In a preparation of Polypeptide Vesicles for drug Delivery• In a formulation of Cross linked Polymermicelles for Cancer Therapeutics

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REFERENCES• The eastern pharmacist August-1998; Vol no 41.• Novel drug delivery systems Y. W.Chien & Dekker

• www.google.com• www.toodoc.com• Encyclopedia of controlled drug delivery systems.

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THANK YOU…