Development and in vitro evaluation of gastroretentive floating tablets of metformin

Abstract

The objective was to evaluate the in vitro effect of hydrophilic polymers: hydroxypropylmethyl cellulose (HPMC); HPMC K4M, HPMC K15M, carbopol and xanthan gum in the formulation of a gastroretentive floating extended-release system of metformin. Compatibility between metformin and excipients was determined by using infrared spectroscopy. Tablets were obtained through wet granulation method and they were evaluated through pharmacothechnical and pharmacopeial tests. Short term stability studies and a comparison between selected formulation and the brand currently marketed were carried out. Prepared tablets with combination of xanthan gum and HPMC K15M showed a successful behavior having a floating lag time of 65 s, a total floating time higher at 13 h and a 94% of released drug at 13 h. The presence of polymers significantly impacted the release rate for metformin. Such behavior represented an advantage in comparison with metformin extended-release tablets currently marketed in Mexico.