Formulation and Evaluation of Floating Sustained Drug Delivery for Metformin HCl Using Combination of Natural and Synthetic Polymers

Metformin hydrochloride is an oral anti-hyperglycemic drug that has long been used in the management of non-insulin-dependent diabetes mellitus. Absorption of metformin hydrochloride is confined to the small intestine. Furthermore, conventional sustained-release dosage forms may be poorly bioavailable since absorption appears to cease or diminish when the dosage forms pass into the large intestine A conventional oral SR formulation releases most of the drug content at the colon, which requires that drug will be absorbed from the colon while metformin has poor colonic absorption. In the case of insufficient colonic absorption, clinical advantage may be acomplished by a SR-gastroretentive dosage form that is retained in the stomach and produces a constant input of the drug to the sites of absorption at the upper part of the gastrointestinal (GI) tract. In this study attempt was made to formulate floating sustained drug delivery system for Metformin HCl using combination of natural and synthetic polymer as Psyllium Husk and HPMC respectively. Sodium bicarbonate was added as a gas generating agent.FTIR and DSC study for Drug – Exciepient compatibility studies showed no interaction between Metformin HCl and polymers used. The granules prepared by wet granulation technique for sustained release layer of drug and polymers was evaluated for Angle of repose, Bulk Density, Tapped Density, Carr's index and Hausner ratio which concluded that these were considerably good to formulate the tablets also the formulated batches showed good in-vitro floating ability throughout the study.