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Preparation and Evaluation of Ethylene Vinyl Acetate Copolymer Coated Microcapsules of Pioglitazone for Controlled Release

K. P. R. Chowdary, Veeraiah Enturi and K. R. Jagadish

The objective of the study is to prepare and evaluate ethylene vinyl acetate copolymer (EVA) coated microcapsules of pioglitazone for controlled release. Controlled release formulations are needed for pioglitazone because of its short biological half life and for better control of blood glucose levels to prevent hypoglycemia, to enhance clinical efficacy and patient compliance. Ethylene vinyl acetate copolymer (EVA) microcapsules of pioglitazone were prepared by an industrially feasible emulsification – solvent evaporation method and the microcapsules were evaluated for controlled release. The ethylene vinyl acetate copolymer (EVA) microcapsules prepared are spherical, discrete, free flowing and multi nucleate monolithic type. Microencapsulation efficiency was in the range 95.0-101.25%. Pioglitazone release from the microcapsules was slow over 24 hours 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 relationships were observed between wall thickness of the microcapsules and release rate. Ethylene vinyl acetate copolymer (EVA) was found suitable as a microencapsulating agent for pioglitazone and the ethylene vinyl acetate copolymer (EVA) microcapsules exhibited good controlled release characteristics and were found suitable for once-a-day administration of pioglitazone.