Abstract

Gastroretentive drug delivery is an approach to prolong gastric residence time, thereby targeting site-specific drug release to the upper gastrointestinal tract (GIT) for local or systemic effects. Metformin, a biguanide glucose-lowering agent has properties of a strong base and is protonated at physiologic pH. The ionized metformin has a tendency to adsorb to the negatively charged intestinal epithelium, thus affecting the drug absorption pattern. Thus,clinical advantage may be accomplished by a sustained release gastroretentive dosage form of Metformin.The aim of this study to develop gastroretentive drug delivery system(GRDDS) of high dose, water soluble Metformin hydrochlorideby combining effervescent mechanism with swellable polymers. The gastroretentive tablets were developed using wet granulation method with hydroxypropylmethyl cellulose (HPMC) of different grades, effervescent agent, PVP K90 as binder and microcrystalline cellulose as diluent. The ratios of polymers and effervescent agents were optimized on the basis of floating time and lag time and the in vitrodrug release. In the present study, floating gastroretentive hydrophilic matrix tablets were successfullydeveloped using HPMC K100M and sodium bicarbonate,which showed more than 90% drug releasedover 10 hours and the developed tablets could float within 1 minute and remained floating for over 24 hours.