Optimization of Aqueous Based Film Coating Technique for Pellets in Colon Specific Delivery of Mesalamine

Mesalamine is an inflammatory agent to treat inflammation of digestive tract (crohn’s disease) and mild to moderate ulcerative colitis. It shows inflammatory activity by blocking cyclooxygenase and prostaglandins production in colon. The multiple unit dosage form of mesalamine in the form of pellets was prepared. The parameters like moisture content, speed of spheronization and spheronization aid (MCC PH 101) were optimized. The pellets were loaded with 40% drug, 90% moisture content, 1% binder PVP K-30 and spheronization speed of 1500 rpm were found to be parameters for pelletization. For drug release in colon inner coating using Eudragit RL RS 30 and outer coating using Eudragit FS 30D was done. In vitro drug release studies clearly revealed that 15% coating levels of eudragit FS 30D withstand acidic media and 1% drug release was observed which was optimum coating level for colon targeting. With aqueous dispersion of eudragit FS 30D (outer coat) at 15% coating level, 1% drug release was observed in pH 1.2 buffer for 2 hours and sustained drug release for 8 hours was obtained in pH 7.2 phosphate buffer. When pH of dissolution media was increased from 6.8 to 7.2, drug release was found to increase from 8.45 to 96.05%. As compared with formulation containing croscarmellose sodium, release rate was decreased with formulation containing crospovidone. Hence, film coated pellets can be used for colonic release of mesalamine.