DEVELOPMENT OF SUSTAINED RELEASE TABLET OF METFORMIN HYDROCHLORIDE BY AQUEOUS COATING

Abstract

The aim of present work was to develop a metformin hydrochloride sustained release tablet by aqueous coating. Eudragit RL and Eudragit RS were used for coating of tablets. Eudragit RL having 10% and Eudragit RS having 5% of functional quaternary ammonium groups, which give rise to pH independent permeability of the polymer. Metformin hydrochloride uncoated tablets were prepared by wet granulation technique. Tablets were coated with blends of Eudragit RS30D and Eudragit RL30D in 5:1 and in 3:1 ratios at different coating level viz. 7%, 5%, 3%, 1.5%, 1%. Two dissolution media: pH 1.2 and pH 6.8 phosphate buffer were employed for in vitro release behaviors of metformin hydrochloride tablets. Coating with blends of Eudragit RS 30D and Eudragit RL 30D in 5:1 and in 3:1 ratio at 1% and at 3% showed sustained release effect for 12 h. The two Eudragit polymers with different features as coating materials produced the desired results.