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Polymer science pradip


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Polymer science pradip

  3. 3. 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 repeatingstructural units or monomers connected bycovalent chemical bonds. The process used for this is known as‘POLYMERIZATION’ 33
  4. 4. Polymerization the use of heat, pressure or a chemical catalyst to link monomer material into polymer chains. 4
  5. 5. 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. 5 5
  6. 6. 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 6 6
  7. 7. CLASSIFICATION1.Simple classification2.Based on their interaction with water3.Based upon linkage4.Based on method of polymerization5.Based on polymerization mechanisms6.Based on composition. 7 7
  8. 8. Simple classification of polymer: POLYMERS NATURAL SYNTHETIC Biodegradable Non biodegradable glycosides and its polymers polyanhydrides Acrolein, epoxy polymersProteinsCarbohydratesNucleic acids 8 8
  9. 9. 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 9 9
  10. 10. 3.Based upon linkage: A. Thermoplastics: e.g. PVA, PVCa. 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 10 10
  11. 11. B. Thermostatic:c. Cross linked polymers e.g. epoxy glue, styrene monomer 11 11
  12. 12. 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 successivereaction of functional group. 12 12
  13. 13. 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. 13 13
  14. 14. addition CondensationExample Polystyrene NylonEmpirical formula No change from Changes as byproduct monomer. (often water) is given off.How grows One monomer at a Monomer + dimer, time hexamer + octadecamer, etc.Molecular weight Wide range: can be Low (except very high biopolymers)Synonym Chain growth Step growth polymerization polymerization 14 14
  15. 15. Addition: one monomer at a timeAlso called chain growth.Condensation: anything goes!Also called step growth. 15 15
  16. 16. 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- 16 16
  17. 17. 7.Biopolymers: Nucleic Acids Ribose sugar OH 5 Base 3 O O P O H O P O H3C O ..... H N N O O OH CH2O P O T N H ...... N A O OH N O O O N H2C OH U O O N N H O O P OH2C O P O H O N O OH O ... H N O O CH2 NO P O O G N H ........ N C OH N O H2C N N OH OH G N O NH ......... O O P O N CH2 O N O O P O H NH2 N N H ..... O CH3 O O CH2 OHO P O N A OH O N ........ H N T OH OH N NH H2C N N O P O A O O H2C O N N H O N O P O N H .. O N O O CH2 OH C N ..... O P O H N G N OH N OH O N H2C O .... H N O 3 NH2 H H2C O C O N N O O P O O P O O O OH 5 17 RNA DNA 17
  18. 18. Applications of polymer in formulation of controlled drug delivery system: 1. ORAL DELIVERY SYSTEM: Here the drug gets released at controlled rate when administered orally. For that several mechanisms are Involved. Osmotic pressure controlled GI deliver system. Gel diffusion controlled GI delivery system Mucoadhesive GI delivery system 18 18
  19. 19. 1.Osmotic Pressure Controlled deliverysystem: Semi permeable membrane made from biocompatible polymerse.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. 19 19
  20. 20. 2.TRANSDERMAL DRUG DELIVERY SYSTEM: Mostly used when the medicaments are applied ontopical route. It is easily removable when terminationof treatment is needed or else in case of condition oftoxicity is seen. e.g. Transdermal patch of scopolamine, nitro glycerin. 20
  21. 21. 3. OCULAR DRUG DELIVERY SYSTEM: It allows prolonged contact of drug with orneal surface of eye. Highly viscous suspension and emulsionare served to have such purpose but thesepreparations don’t achieve this purpose ata controlled rate. Many ocular drug delivery formulationsdeveloped which continuously release thedrug at a controlled rate 21
  22. 22. The best example is ocular insert/ocusertdeveloped to delivered pilocarpine in thetreatment of glaucoma Example of pilocarpine ocusert 22
  23. 23. 4.Other applications: Drug Delivery and the Treatment ofDiabetes: Here the polymer will act asBarrier between blood stream and insuline.g. of polymer- N,N-dimethylaminoethylmethacrylateor polyacrylamide. 23
  24. 24. Drug delivery of various contraceptivesand hormones:e.g. Medroxy progesterone acetate releasingvaginal contraceptive rings. 24
  25. 25. Various uses of polymer inpharmaceutical 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 25
  26. 26. REFERENCES• The eastern pharmacist August-1998; Vol no 41.• Novel drug delivery systems Y. W.Chien & Dekker••• Encyclopedia of controlled drugdelivery systems. 26
  27. 27. THANK YOU… 27