Polymer Science

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Polymer Science

  1. 1. <ul><li>BIODEGRADABLE POLYMERS AND NATURAL POLYMERS </li></ul><ul><li>PRESENTED BY </li></ul><ul><li>SHIVA KUMAR Y </li></ul><ul><li>M.PHARMACY 1 ST yr </li></ul><ul><li>K.L.E UNIVERSITY.Belgaum </li></ul>
  2. 2. <ul><li>DEFINITION </li></ul><ul><li>BIODEGRADABLE POLYMERS </li></ul><ul><li>MECHANISM OF BIODEGRADATION </li></ul><ul><li>NATURAL POLYMERS </li></ul><ul><li>CONCLUSION </li></ul><ul><li>REFERENCES </li></ul>CONTENTS
  3. 3. POLYMER DEFINITION Polymers are long chain organic molecules and are assembled from many smaller molecules called monomers They mostly contain elements like C,H,O,N,P etc,.
  4. 4. 1)Schematic Illustration Of Control Drug Release,2) Single dose administration
  5. 5. Biodegradable polymers <ul><li>These are the Polymers which Degrade slowly and get expelled out of the body </li></ul><ul><li>after fulfilling its action i.e., Drug release . </li></ul><ul><li>The most imp mechanism for degradation </li></ul><ul><li>is chemical reaction – i.e. Hydrolysis. </li></ul>
  6. 6. BIODEGRADATION ENZYMATIC DEGRADATION COMBINATION HYDROLYSIS BULK EROSION SURFACE EROSION MECHANISM OF BIODEGRADABLE POLYMERS
  7. 7. TYPE 1A TYPE 1B
  8. 8. A A A B B B A  B represents hydrolysis , ionisation or protonation TYPE 2 TYPE 3 HIGH Mol.wt LOW Mol.wt
  9. 9. Factors Influencing Biodegradation <ul><li>: </li></ul><ul><li>CHEMICAL STRUCTURE </li></ul><ul><li>(a) Functional Group </li></ul><ul><li>(b) Hydrophobicity </li></ul><ul><li>MORPHOLOGY </li></ul><ul><li>(a) Crosslink density </li></ul><ul><li>PARTICLE SIZE </li></ul>
  10. 10. Pre Requisites of B-D-Polymers <ul><li>BIO COMPATABILITY </li></ul><ul><li>MECHANICAL STRENGTH </li></ul><ul><li>STABILITY </li></ul><ul><li>BIO RESORBIBILITY </li></ul><ul><li>INERT </li></ul><ul><li>Biodegradation : It is the process of chain cleavage, </li></ul><ul><li>Found out by change in Mol.wt. </li></ul><ul><li>Bioerosion : It is the sum of all process, leading to loss </li></ul><ul><li>Of mass from a polymer matrix. </li></ul><ul><li>Note : Hydrophobic polymers have to undergo degradation before Erosion takes place. </li></ul>
  11. 11. TYPES OF BIODEGRADABLE POLYMERS <ul><li>POLY ESTERS </li></ul><ul><li>POLY PHOSPHO ESTERS </li></ul><ul><li>POLY ANHYDRIDES </li></ul><ul><li>POLY OLEFINS </li></ul><ul><li>POLY AMIDES </li></ul>
  12. 12. <ul><li>POLY (GLYCOLIC ACID) ---(--O—C-CH 2 ---) n </li></ul><ul><li>POLY (LACTIC ACID) --(--O---C—CH---) n </li></ul><ul><li>POLY (CAPROLACTONE) --(--O—C---(CH 2 ) 5 ---) n </li></ul><ul><li>First polymers used in medicine dated back to 1954 . </li></ul><ul><li>Most commercialised class of Polymers </li></ul><ul><li>ex : ADRIAMYCIN ® </li></ul><ul><li>Bio compatible & Bio resorbable </li></ul><ul><li>Synthesis & Co polymerisation can be easily done </li></ul><ul><li>t ½ ranges from weeks (PLA) to years (PCL). </li></ul><ul><li>APPLICATIONS : (1) Sutures, ligatures etc. </li></ul><ul><li>(2) DECAPEPTYL ® , LUPRON DEPOT ® </li></ul>o CH 3 o o POLY ESTERS
  13. 13. Poly (lactide) rods implanted into Rabbits <ul><li>(9 weeks) (16 weeks) </li></ul>Degradation is mainly by : (1) ENZYMATIC (2) HYDROLYTIC (3) MICROBIAL ex : Esterase, pronase, bromelain HYDROLYSIS : R—COO---R 1 + H 2 O R—COOH + R 1 –OH MICROBIAL DEGRADATION : Fungi – ‘ FUSARIUM MONILIFORMAE’ YEAST- ‘CRYPTOCOCCUS’
  14. 14. POLY PHOSPHO ESTERS <ul><li>O </li></ul><ul><li>--(--P---O---R---O--)-- Poly (Phosphate ) </li></ul><ul><li>OR 1 </li></ul><ul><li>O </li></ul><ul><li>--(--P---O---R---O--)-- Poly (Phosphonate) </li></ul><ul><li>R 1 </li></ul><ul><li>Highly Adjustable properties </li></ul><ul><li>Good Biocompatabilty </li></ul><ul><li>High Degradability </li></ul><ul><li>High Mol.wt gives good strength </li></ul>
  15. 15. <ul><li>Get Degraded within 6 months </li></ul><ul><li>t 1/2 is from 2 to 4 months </li></ul><ul><li>Degradation products – phosphates & alcohol </li></ul><ul><li>APPLICATIONS : Paclitaxel, cisplatin </li></ul><ul><li>Plasmid DNA, IL-2 </li></ul><ul><li>STERILISATION & STABILITY : </li></ul><ul><li>Highly Susceptible to Hydrolysis in Open Air </li></ul><ul><li>Should be stored in a Dessicator </li></ul><ul><li>Sterilisation Only by Gamma Irradiation </li></ul>DRUG RELEASE :
  16. 16. POLY ANHYDRIDES <ul><li>HO--[---(C—R 1 ----C) n1 -----O-----(C---R 2 ---C-) n2 --] n3 ---OH </li></ul><ul><li>GENERAL STRUCTURE </li></ul><ul><li>Two carboxylic groups at each end </li></ul><ul><li>High Degradation rate </li></ul><ul><li>Degrade by Surface Erosion </li></ul><ul><li>Aromatic P.A’s are slower degrading </li></ul><ul><li>Copolymerisation can control degradation rate </li></ul><ul><li>Biological tests in Rabbits proved them Non-mutagenic </li></ul><ul><li>APPLICATIONS : 1) PEPTIDES FOR OSTEOMYLITES </li></ul><ul><li>2) PROTIENS FOR BRAIN TUMOUR </li></ul>
  17. 17. DRUG RELEASE : <ul><li>Mostly they degrade by Surface Erosion (S.E) </li></ul><ul><li>Their t 1/2 is less than 30 days </li></ul><ul><li>Due to S.E. proportion of drug released </li></ul><ul><li>alters with time </li></ul><ul><li>DRUG STABILITY : </li></ul><ul><li>Primary amine containing drugs react at pH 7.2 </li></ul><ul><li>The above reaction is not seen below pH 5.0 </li></ul><ul><li>They are ideal when action is required for 1 week </li></ul><ul><li>They have more application as parentrals. </li></ul>
  18. 18. POLY OLEFINS <ul><li>PROPERTIES : </li></ul><ul><li>Carbon Chain based Polymers </li></ul><ul><li>They contain Double & Triple bonds extensively </li></ul><ul><li>Presence of substituents like Cyanoacryl groups </li></ul><ul><li>enhance Degradation rate </li></ul><ul><li>An Example for rapidly oxidized olefin is </li></ul><ul><li>Poly propylene </li></ul><ul><li>Introduction of vinyl group makes them more stable </li></ul><ul><li>ex : Teflon </li></ul><ul><li>APPLICATIONS : 1) SUTURES,CATHETERS,IMPLANTS </li></ul><ul><li>2) MEMBRANE BARRIER FOR DRUGS </li></ul>
  19. 19. POLY AMIDES <ul><li>PROPERTIES : </li></ul><ul><li>These Are Generally Called As ‘ NYLONS ’. </li></ul><ul><li>They Are Generally Slowly Degrading </li></ul><ul><li>BY INTRODUCTION of COPOLYMERS like </li></ul><ul><li>‘ L-Aspartic Acid ', Nearly 40% of Polymer Is </li></ul><ul><li>Degraded within 1 week. </li></ul><ul><li>Mainly degraded In vivo by Non-specific ‘Amidases’ </li></ul><ul><li>They are more stable when compared to other </li></ul><ul><li>Polymers </li></ul><ul><li>APPLICATIONS : Haemofiltration Membranes, </li></ul><ul><li>Dressings, sutures etc. </li></ul>
  20. 20. ADVANTAGES : <ul><li>Play an essential role in Formulation of CDDS </li></ul><ul><li>Patient compliance is improved </li></ul><ul><li>Bio compatible </li></ul><ul><li>Help in adjusting duration of action of Drug </li></ul><ul><li>Most of them are Inert </li></ul><ul><li>Copolymerisation can be done </li></ul><ul><li>DISADVANTAGES : </li></ul><ul><li>Most of them are Expensive </li></ul><ul><li>Drug release cannot be 100% predicted </li></ul>
  21. 21. NATURAL POLYMERS <ul><li>These are the polymers obtained from natural </li></ul><ul><li>Resources, and are generally Non-toxic. </li></ul>NATURAL POLYMERS PROTEINS Polysaccharides Nucleic Acids Ex: COLLAGEN ALBUMIN FIBRIN Ex : DEXTRAN CHITOSAN STARCH Ex : DNA RNA ADVANTAGES : 1) Readily & Abundantly Available 2) Comparatively Inexpensive 3) Non toxic products 4) Modified to get semi synthetic forms
  22. 22. PROTEINS <ul><li>COLLAGEN: </li></ul><ul><li>It is a major structural protein in animals </li></ul><ul><li>It is used as sutures ,Dressings, etc. </li></ul><ul><li>Readily isolated &purified in large quantites. </li></ul><ul><li>Can be processed in variety of forms . </li></ul><ul><li>DISADVANTAGES: </li></ul><ul><li>Chance of antigenic response. </li></ul><ul><li>Variability in drug release kinetics. </li></ul><ul><li>Poor mechanical strength. </li></ul>
  23. 23. FIBRINOGEN : <ul><li>Soluble Plasma protein (M.W. 3,40.000) </li></ul><ul><li>It is commonly used as Coagulant </li></ul><ul><li>Useful in preparation of Micro spheres of Anti cancer agents </li></ul><ul><li>DISADVANTAGES : </li></ul><ul><li>ANTIGENICITY </li></ul><ul><li>INTERACTION WITH DRUG </li></ul><ul><li>IMPROPER DRUG RELEASE </li></ul><ul><li>LESS SHELF LIFE </li></ul>
  24. 24. Polysaccarides <ul><li>DEXTRAN : </li></ul><ul><li>Dextran is a complex branched polysaccharide made of many glucose molecules joined into chains of varying lengths </li></ul><ul><li>It consists of α-D-1,6-glucose-linked glucan with side-chains linked to the backbone of Polymer </li></ul><ul><li>Mol.wt ranges from 1000 to 2,00,000 Daltons </li></ul><ul><li>Enzymes from moulds such as ‘PENCILLIUM’ degrade it. </li></ul><ul><li>APPLICATIONS – 1) Replacement of Blood loss </li></ul><ul><li>2) Thrombosis Prophylaxis </li></ul><ul><li>3) Improvement of Rheology </li></ul>
  25. 25. CHITOSAN : <ul><li>It consists of B-1-4 linked 2 amino-2-deoxy gluco - </li></ul><ul><li>pyranose moieties </li></ul><ul><li>Commercially manufactured by N-deacetylation of </li></ul><ul><li>Chitin which is obtained from Mollusc shells </li></ul><ul><li>It is soluble only in acidic pH i.e. when amino </li></ul><ul><li>group is protonated. </li></ul><ul><li>Thereby it readily adheres to bio membranes. </li></ul><ul><li>It is degraded mainly by Glycosidases & lysozymes. </li></ul><ul><li>ADVANTAGES : </li></ul><ul><li>Free availability, Biocompatibility, Biodegradability </li></ul><ul><li>Bioadhesive, unique properties. </li></ul>
  26. 26. conclusion <ul><li>Polymers play an essential role in the </li></ul><ul><li>Development of CDDS </li></ul><ul><li>The potential of Copolymerisation should </li></ul><ul><li>be deeply understood & applied. </li></ul><ul><li>New Biodegradable polymers should be </li></ul><ul><li>Investigated </li></ul><ul><li>Natural polymers should not be under- </li></ul><ul><li>Estimated as they have high potential </li></ul><ul><li>And readily Available </li></ul>
  27. 27. REFERENCES: <ul><li>S.P.VYAS AND R.K.KHAR ,CONTROLLED DRUGE DELIVERY CONCEPT AND ADVANCES,FIRST EDITION 2002. </li></ul><ul><li>CONTROLLED DRUG DELIVERY SYSTEM BY STEPHEN D.BRUCK. </li></ul><ul><li>CONTROLLED AND NOVEL DELIVERY SYSTEM N.K.JAIN </li></ul><ul><li>INDIAN DRUGS .VOL-39;2002 </li></ul><ul><li>INDIAN DRUGS.VOL-30;1993. </li></ul><ul><li>www.google.com </li></ul>
  28. 28. <ul><li>THANK YOU </li></ul>

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