Design and Characterization of Dual Drug Loaded Microspheres for Colon Drug Targeting

The present investigation was focus to prepared and characterized eudragit coated pectin microspheres for the delivery of mesalamine and prednisolone to the colon. The pectin microspheres were prepared using emulsion dehydration technique. A 33 full factorial design (three variables in three levels) was employed to evaluate the combined effect of the selected independent variables: drugs to polymer ratio, emulsifier concentrations and stirring speed on dependent variables such as particle size and size distribution, percentage yield, % drug entrapment and swelling ratio. Optimized formulation i.e. F18, F24, and F27 were coated with eudragit S100 by the solvent evaporation technique to prevent drug release in the stomach. Eudragit S100 coated pectin microspheres were further characterized for coating thickness and in-vitro release kinetics. The cumulative percent drug release of mesalamine and prednisolone from formulation in pH 7.4 phosphate buffer was found to be 97.01 + 1.35% and 96.89 + 0.67% for mesalamine and prednisolone, respectively. Optimized formulation (F24) was characterized for in-vivo studies. The eudragit-coated pectin microspheres may improve therapeutic efficacy by local action and reduce the side effects by minimizing the systemic absorption of mesalamine and prednisolone. Amalgamation of mesalamine and prednisolone in therapeutic regimen will show synergism action for treatment of UC.