Formulation, Evaluation and Optimization of Controlled Release Hydrogel Microspheres for Colon Targeted Drug Delivery

The purpose of this research was to established new polysaccharide for the colon targeted drug delivery system, its formulation and in vitro and in vivo evaluation. Microspheres containing chitosan and bora rice were prepared by simple emulsification phase separation technique using glutaraldehyde as cross linking agent and model drug used was glipizide. Results of trial batches indicated that polymer to drug ratio and stirring speed affects characteristics of microspheres. Microspheres were discrete, spherical and free flowing. Microspheres exhibited small particle size, higher percentage yield and also showed higher percentage of drug entrapment efficiency. A 3 full factorial design was employed to study the effect of independent variables, polymer to drug ratio (A), and stirring speed (B) on dependent variables, particle size, swelling index, drug entrapment efficiency and percentage drug release. The optimized batch C2 exhibited satisfactory drug entrapment efficiency 63% and drug release was also controlled for more than 24 hours. The polymer to drug ratio had a more significant effect on the dependent variables. In vivo gamma scintigraphy study of optimized chitosan-bora rice microsphere demonstrated degradation of microspheres whenever they reached to the colon. Hence bora rice is potential polysaccharide for colon targeted drug delivery system.