Formulation and Evaluation of Floating Bilayer Tablet of Metformin Hydrochloride and Glimepiride.

There has been 60 years of research and development experience in the sustained drug release area since the patent, and a number of strategies have been developed to prolong drug level in the body. With many drugs, the basic goal of therapy is to achieve a steady-state blood or tissue level that therapeutically effective and non-toxic for an extended period of time. Floating Bilayer tablet of Metformin HCl SR and Glimepiride IR were formulated using HPMC K4M, HPMC E-15 and HPMC E-15 in alone (80%) and in combination of different percentage of polymer (20&60%,40&40% and 60&20%). Three different formulations (M4, M8 &M12 ) of floating Metformin HCl SR tablets are prepared by employing the hydrophilic polymer HPMC in different viscosity grades in the percentage of 80%. From that M12 formulation were found to be suitable for formulating SR tablet by its in vitro release. From the M12 formulation, it was clear that when the polymer concentration increases it decreases the release rate. Formulations of C1-C9 of floating Bilayer tablets are prepared by combining the different viscosity polymers (HPMC K4M+HPMC E-15, HPMC E-15+HPMC E-5 & HPMC E-5+HPMC K4M) in the percentage 0f 20&60%,40&40% and 60&20% The formulation C3 (HPMC K4M[60%]+HPMC E-15[20%]), C6 (HPMCE-5 [20%]+HPMCE-15[60%]) and C7 (HPMC K4M[60%] + HPMC E-5[20%]) were found to suitable for formulating SR by its in vitro release studies and it show release about 101.92%, 88.47% and 92.25%. From the C3 formulation it was shown that the percentage of high viscosity polymer can be reduced by adding low viscosity polymer. From the dissolution profile of formulation C3 it was well understood that the release of drug from its formulation can be improved by combining the low and high viscosity polymers compared to formulating M12 high viscosity polymer alone. From this study it was concluded that Floating time increases, it decreases the release rate. So it suitable for sustained release formulation.