FORMULATION DEVELOPMENT AND EVALUATION OF ONCE DAILY SUSTAINED RELEASE METFORMIN HYDROCHLORIDE TABLETS

Abstract

Metformin hydrochloride has relatively short plasma half-life and low absolute bioavailability. The need of administration for two to three times a day when larger doses are required can decrease patient compliance. Sustained release formulation that would maintain plasma level for 20 h might be sufficient for daily dosing of metformin. Sustained release products are needed for metformin to prolong its duration of action and to improve patient compliances. The overall objective of this study was to develop an oral sustained release metformin hydrochloride tablet by using hydrophilic alone or its combination with hydrophobic as rate controlling factor. The tablets were prepared by granulation method. The in vitro dissolution study was carried out using USP 22 apparatus I, paddle method. The drug release study revealed that HPMC alone was unable to sustain the drug release. Combining HPMC 8 HEC and coting with a semi-permeable membrane with controlled release from an orifice, sustained the drug release for more than 20h.