Biodegradable polymeric delivery system

Biodegradable polymeric delivery system

1. BIODEGRADABLE POLYMERS Nature’s way: “Every resource made by nature returns to nature”

2. HOW LONG DOES IT TAKE? POLYMERIC MATERIAL DEGRADATION TIME Cotton rags 1-5 months Paper 2-5 months Rope 3-14 months Orange peels 6 months Wool socks 1 to 5 years Cigarette butts 1 to 12 years Plastic coated paper milk cartons 5 years Plastic bags 10 to 20 years Nylon fabric 30 to 40 years Aluminum cans 80 to 100 years Plastic 6-pack holder rings 450 years Glass bottles 1 million years Plastic bottles May be never

3. HISTORY When polymers were synthesized from glycolic acid in 1920s, a t that time, polymer degradation was viewed negatively as a process, where properties and performance deteriorated with time .

4. BIODEGRADABLE POLYMER: DEFINITION “Polymers that degraded/eroded by enzymes introduced in vivo or surrounding living cells or Degraded/eroded by non enzymatic process into oligomers ,after their intended purpose to result in natural byproducts (gases : CO 2 ,  N 2 ;  water, biomass, and inorganic salts )” Byproducts are metabolized and removed from the body via normal metabolic pathways.

5. ADVANTAGES Less toxic compared to non-biodegradable polymers Much higher doses of the drug can be delivered locally Controlled drug release from the formulation Stabilization of drug Localized delivery of drug Decrease in dosing frequency Reduce side effects Improved patient compliance Polymer retain its characteristics till the depletion of drug

6. BIODEGRADABLE POLYMERS: classification A: BASED ON ORIGIN Natural origin : Collagen, Albumin, Casein, etc. Semi-synthetic polymers : Gelatin, Dextran , Chitin, Alginate, Chitosan , etc. Synthetic polymers : Aliphatic polyesters : PGA, PLA,PCL, etc. Polyphosphoesters , polyanhydrides , polyphosphazenes , polyaminoacids B. BASED ON ENVIORNMENTAL FACTORS: Thermosensitive polymer: Polyacrylamide , etc. Electrically and chemically controlled: Poly( pyrrole ), collagen, etc. pH sensitive polymer: poly (2-ethylacrylic acid), etc . C. MISCELLANEOUS: Polymeric phospholipids, Polyethyleneamine , Polyamidoamine, PEG

7. DIFFERENT MECHANISMS OF DEGRADATION Chemical degradation Physical degradation Enzymatic degradation

8. ENZYMATIC OR CHEMICAL DEGRADATION Chemical or enzymatic degradation–mediated by water , enzymes, microorganisms. CLEAVAGE OF CROSSLINKS TRANSFORMATION OF SIDE CHAINS CLEAVAGE OF BACKBONE

9. BIODEGRADABLE POLYMERS Acetal: Hemiacetal: Ether Nitrile Phosphonate Polycyanocrylate O C C C C C OH OH OH OH OH OH C C C C OH OH OH OH H 2 O + C==O H H 2 O

10. 1) Bulk erosion Degradation takes place throughout the whole of the sample. Water intake is faster than the polymer chain scission Eg : polyesters, PLA, PLGA, polylactones , poly(amino acids), and polyphosphazenes 2) Surface erosion Sample is eroded from the surface. polymer degradation is much faster than water intake E.g. Polyanhydrides , polyorthoesters 11 PHYSICAL DEGRADATION

11. METHODS OF STUDYING POLYMER DEGRADATION Morphological changes (swelling, deformation, bubbling, disappearance) Weight loss Thermal behavior changes (DSC) Molecular weight changes Size exclusion chromatography Gel permeation chromatography Mass spectroscopy Change in chemistry (IR, NMR)

12. MOLDING (Formation of drug polymer matrix) Methods: Compression molding Melt molding Solvent casting Compression molding Polymer and drug particles are milled to a particle s ize range of 90-150 µm Drug/polymer mix is compressed at approx. 30,000 psi Formation of some types of tablet/matrix

13. MELT MOLDING

14. SOLVENT CASTING

15. APPLICATIONS OF BIODEGRADABLE POLYMERS Polymer system for gene therapy. Biodegradable polymer for ocular, tissue engineering, vascular, orthopedic, skin adhesive & surgical glues. Biodegradable drug delivery system for therapeutic agents such as anti-tumor , antipsychotic agent, anti-inflammatory agent. Polymeric materials are used in and on soil to improve aeration, and promote plant growth and health. Many biomaterials, especially heart valve replacements and blood vessels, are made of polymers like Dacron, Teflon and polyurethane. Particulate carriers such as micro- and nanoparticles are suitable for both implantation and circulation Whereas cylindrical devices are meant only for implantation.

16. APPLICATION

17. APPLICATION

18. APPLICATION: as a Drug Delivery System

19. APPLICATION: as a n ocusert

20. BIODEGRADABLE POLYMERS: Application in drug delivery

21. BIODEGRADABLE POLYMERS: Application in drug delivery

22. BIODEGRADABLE POLYMERS: Application in drug delivery

23. INDIVIDUAL APPLICATION OF BIODEGRADABLE POLYMERS POLYMERS APPLICATION Collagen In wound repairing Chitosan Gelling agent Dextran Plasma volume expander Lectins As a mucoadhesive Cyclodextrins, guar gum, pectin, insulin Delivery of drug to colon Poly -€-caprolactone Microspheres, implants Rosin As an adhesive in TDDS

24. INDIVIDUAL APPLICATION OF BIODEGRADABLE POLYMERS POLYMERS APPLICATION PLA, PLGA Excipients for injectable drugs PLA + Doxycycline…….periodontal disease PLGA + Growth hormone…Growth deficiency PLA + Leuprolide acetate….Prostate cancer

25. CONCLUSION Numerous synthetic biodegradable polymers are available and still being developed for sustained and targeted drug delivery applications. Biodegradable polymers have proven their potential for the development of new, advanced and efficient DDS and capable of delivering a wide range of bioactive materials. However, only few have entered the market since many drugs faces the problem of sensitivity to heat, shear forces and interaction between polymers. These problems can be overcome by fully understanding the degradation mechanism to adjust the release profile.  

26. REFERENCES Kumari A,  Yadav SK,  Yadav SC (2010); “Biodegradable polymeric nanoparticles based drug delivery systems”; Colloids Surf B Biointerfaces