Gas Powered Bioadhesive Tablets of Metformin Hydrochloride: In Vitro Evaluation

The low bioavailability and short half life of Metformin HCl make the development of gas powered mucoadhesive dosage forms desirable. However, drug absorption is limited to upper gastrointestinal tract thus requiring suitable drug delivery system providing complete release during stomach to jejunum transit. This study was undertaken to develop a Metformin HCl gas powered bioadhesive formulation in compliance with these requirements. The strategy proposed is based on direct compressed tablets consisting of a combination of Metformin HCl with different viscosity grades of HPMC (K4M, K15M, and K100M), Carbopol 934P, Xanthan gum and gas generating agent sodium bicarbonate with citric acid. Compatibility among the formulation components was assessed by FTIR. All the tablets were examined for post compressional analysis, drug release and bioadhesive strength. The result of the kinetics study obtained permits us to conclude that the fabricated tablets in this case, deliver the drug through diffusional dominated mechanism.