SWELLABLE AND FLOATING GASTRORETENTIVE FORMULATION FOR SUSTAINED DELIVERY OF METFORMIN HCL

Metformin HCl (MH), is an oral anti-diabetic drug with less bioavailability, and a BCS class III, short plasma half-life as well as narrow absorption window. The objective of this research work is to obtain better delivery of MH to the upper part of GIT by increasing the mean residence time (MRT) in the stomach. For this, Gastroretentive swellable and floating sustained release tablets were prepared to prolong the gastric emptying that provides maximum drug at the site of absorption. Different formulations were prepared by wet granulation with the help of hydrophilic polymers like different grades of hyroxypropyl methyl cellulose (HPMC), xanthan gum (XG), sodium alginate (SA), carbopol 940; hydrophobic polymer like ethyl cellulose (EC); swelling agent like crospovidone (CP) and gas generating agent sodium bicarbonate (SBC). The formulations were evaluated for pre and post-compression characteristics; the formulation F5 gave the optimum result along with >24 hrs floating time and an in vitro release profile very near to desire release. Release kinetic studies showed that all batches followed Super case II transport mechanism and first order kinetics. The optimized formulation F5 also subjected to 40°C and 75% relative humidity for stability test and remained stable during the period of 3 months.