1. POLYMERS FOR COATING

5. Types of Coating

6. Mechanism of coating

11. Plasticizers Class Examples Polyhydric alcohols Propylene glycol Glycerol Polyethylene glycol Acetate esters Glyceryl triacetate Triethyl citrate Acetyl triethyl citrate Phthalate esters Diethyl phthalate Glycerides Acetylated monoglycerides Oils Castor and mineral oil.

12. Polymers

13. Polymers for conventional coating Class Examples Cellulosics HPMC HPC HEC MC (Methocel) Na-CMC EC (Ethocel) Vinyls PVP Glycols PEG Acrylics Co-polymers such as methyl methacrylate, ethyl methacrylate

19. Polymers used for enteric coating.

20. Enteric Coating Polymers Polymer Characteristics Cellulose Acetate Phthalate Susceptible to Hydrolysis Cellulose Acetate Trimellitate Susceptible to Hydrolysis Polyvinyl Acetate Phthalate Susceptible to Hydrolysis HPMC-Phthalate Susceptible to Hydrolysis HPMC-Acetate Succinate Susceptible to Hydrolysis Poly (MA -EA) 1 : 1 ------ Poly (MA -MMA) 1 : 1 High Dissolution pH Poly (MA -MMA) 1 : 2 High Dissolution pH

23. Commercially available enteric coating systems Product Polymer Form Characteristic Eudragit L30D Poly (MA-EA) 1:1 Latex Dispersion Essentially contains only polymer Eudragit L 10055 Poly (MA-EA) 1:1 Spray Dried latex Dispersed in water + allkali Coateric PVAP Dry powder Dispersed in water + ammonia Aquateric CAP Spray dried pseudo latex Dispersed in water CAP CAP Dry powder Dissolved in water + alkali CAT CAT Dry powder Dissolved in water + alkali HPMC-P HPMC Dry powder Dispersed in water

24. Eudragits

25. Eudragits Eudragits Availability applications Dissolution properties Eudragit L 100-55 Powder Drug delivery in duodenum > 5.5 Eudragit D 100-55 Aqueous dispersion 30% Drug delivery duodenum >5.5 Eudragit L 100 Powder Drug delivery in jejunum >6.0 Eudragit S 100 Powder Drug delivery in ileum >7.0 Eudragit FS 30 D Aqueous Dispersion 30% drug delivery in colons. >7.0

28. Release profile Influence of method of manufacture on the release of 5-ASA from Eudragit L100-55 tablets in 0.1 N HCl dissolution media (pH 1.2). () HME tablet; (■) compressed tablet with hardness value of 62 ± 2 N; (○) compressed tablet with hardness value of 230 N ± 12 N.

34. Thank us “If we knew what we were doing, it would not be called research”