BILAYER TABLET FORMULATION OF METFORMIN HYDROCHLORIDE AND GLIPIZIDE: A NOVEL APPROACH IN THE TREATMENT OF DIABETES Research Article

The emerging new fixed dose combination of Metformin Hydrochloride (HCl) as sustained release and Glipizide as immediate release were formulated as a bilayer matrix tablet. Metformin was formulated using Hydroxy Propyl Methyl Cellulose (HPMC) as the matrix forming polymer, and the tablets were evaluated for their physical characteristics and in vitro release. Three different grades of (HPMC K 4M, HPMC K15M, HPMC K100M) were used. In vitro release studies were carried out with a phosphate buffer of pH 6.8 using USP dissolution apparatus 2 (paddle). Tablet thus formulated using HPMC K100M provided sustained release of Metformin HCl over a period of 10 hours. Glipizide is a poorly water soluble (BCS class 2) antidiabetic drug. Due to the poor water solubility of this drug, its bioavailabilty is dissolution rate-limited. The purpose of this study is to increase the solubility of Glipizide by solid dispersion technique with sodium starch glycolate using the kneading method. The Glipizide-Sodium Starch Glycolate solid dispersion system was characterized by FT-IR and in vitro dissolution studies. In-vitro release studies were carried out with a phosphate buffer of pH 6.8 using USP dissolution apparatus 2 (paddle). Tablet thus formulated using drug and carrier at 1:8 ratio provided immediate release of Glipizide over a period of 10 minutes. SR fixed dose bilayer matrix tablets containing 500mg Metformin HCl as SR from one layer and 5mg Glipizide as IR from another layer can be prepared by solid dispersion method.