PREPARATION AND IN VITRO EVALUATION OF SUSTAINED RELEASE TABLET FORMULATIONS OF METFORMIN HCL

An attempt was to formulate the oral sustained release metformin hydrochloride matrix tablets by using hydroxypropyl methylcellulose of different viscosity grades (HPMC K4M, HPMC K15M, and HPMC K100M). The tablets were prepared by wet granulation technique. The granules were evaluated for angle of repose, loose bulk density, tapped and bulk density. It shows satisfactory results. The tablets were subjected to thickness, weight variation, drug content, hardness, friability, and in vitro release studies. The in vitro dissolution study was carried out for 8 h using USP dissolution apparatus II (paddle) in 900mL 0.1 N HCl as dissolution media. The release mechanisms were explored and explained with zero order, first order, Higuchi, Kromayer’s and Hixon-Croweel equations. The optimized formulation was found to be buoyant for 8 h in stomach. It is cleared that the drug release from matrix tablets prepared by HPMC K100M provides a better result in preparation of SR formulation of metformin hydrochloride.