To study the comparative dissolution profiles of sustained release tablets of metformin hydrochloride by using various hydrophilic polymers

In this research study an attempt was made to formulate sustained release matrix tablets of Metformin Hydrochloride as it possesses relatively shorter plasma half-life, low bioavailability. The sustained release formulations of the drug were capable of maintaining the plasma level for 8-12 hours. The overall objective of this research was to formulate the tablet by using various hydrophilic polymers i.e. Xanthan gum, Guar gum, Aloe barbadensis and Methocel K4M. Tablets were prepared by wet granulation method. In Vitro studies were performed by USP XX apparatus I, basket and the data was analyzed using zero order, first order, and Korsmeyer and Higuchi models. Nine formulations were made, out of which F-9 formulation which was composed of Aloe Barbadensis in the ratio of 1:2, with combination of other polymers (xanthan gum, guar gum and methocel K4 M) showed maximum drug release within 12 hours with sustained release profile because Aloe barbadensis showed maximum swelling followed by entanglement of polymers chains, thus gave maximum gel strength which provides main retarding factor for the drug release. The use of three polymers (xanthan gum, guar gum and methocel K4M) alone in the different formulations i.e. from F-1 to F-6 was not able to sustain the drug release because of their rapid solubilization in acidic pH leads to pores in the matrix, finally causes surface erosion and initial disaggregation of the matrix tablet prior to gel layer formation around tablet core causes rapid release of the drug within 1 hour as compared to F-9 formulation. Keywords: Sustained drug delivery system, Aloe Vera, Methocel K4M, Xanthan gum, Guar gum and Metformin HCl