Preparation and Evaluation of Starch Acetate Coated Microcapsules of Glipizide for Controlled Release

Abstract

Starch acetate was evaluated as microencapsulating agent and to prepare starch acetate coated microcapsules. Starch acetate coated microcapsules of glipizide were prepared by an industrially feasible emulsification-solvent evaporation method and the microcapsules were investigated. The starch acetate coated microcapsules are spherical, discrete, free-flowing and multinucleate monolithic type. Microencapsulation efficiency was found to be in the range 87.5-98.8 %. Glipizide release from the SA coated microcapsules was slow and extended over longer periods of time and depended on core: coat ratio, wall thickness and size of the microcapsules. Drug release from the microcapsules was by non-fickian diffusion mechanism. Good linear relationship was observed between wall thickness of microcapsules and release rate (k₀) and (k₁). Starch acetate was found suitable as microencapsulating agent and the starch acetate coated microcapsules of glipizide exhibited good controlled release characteristics and were found suitable for oral contro-lled release products.