Preparation and in Vitro Drug Release Evaluation of Once-Daily Metformin Hydrochloride Sustained-Release Tablets

The objective of this study was to develop once-daily metformin hydrochloride sustained-release tablets (MHSRT) and evaluate their in vitro release behavior. MHSRT were prepared by the film coating method. The in vitro drug release rate of MHSRT and the commercial tablets Fortamet made in the United States of America in water was fitted with zero order kinetic equation, and Ritger-Peppas kinetic equation in 0.1 M HCl and pH 6.8-phosphate buffer, respectively. The similarity factor f2 values of MHSRT in three different dissolution medium were 82, 80 and 74, respectively in comparison with imported Fortamet, which were all greater than 50. The results of storage-stability showed that MHSRT were stable for at least 6 months under stress condition (40 ̊C ± 2 ̊C, RH 75% ± 5%). Therefore, in this study, MHSRT were successfully prepared using optimized formulation technologies that meet mass produce. The in vitro release behavior of MHSRT was almost similar to that of imported Fortamet.