Formulation and Evaluation of Taste Masked Sustained Release Dosage Form of Metformin Hydrochloride Using Indion Resin

Sustained release formulation of metformin hydrochloride (MTHCL) presents significant challenges due to its poor inherent compressibility, high dose and high water solubility. Thus formulating MTHCL into an sustained dosage form would provide slow release. But, it is bitter in taste and taste should be masked to formulate it in a palatable form. So in the work undertaken, an attempt was made to sustained the release as well as to mask the bitter taste by complexation technique using strong cationexchange resin, Indion 254 and Indion 264 (Polyacrylic hydrogen with carboxylic functionality). The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, mode of mixing, ratio of drug:resin and temperature. The resinate was evaluated for micromeritic properties, taste masking and characterized by X-Ray diffraction study and IR. Using resinate sustained release tablets were formulated using Hydoxy propyl methyl cellulose (K100M: HPMC) as binder and microcrystalline cellulose(MCC) as diluent. The tablets were evaluated for hardness, thickness,friability,drug content, weight variation and invitro drug release. Tablets thus formulated (Batch B-6) provided sustained release of drug over a period of time 10 hours with First order kinetics. The release of MTHCL from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. The results showed that MTHCL was successfully taste masked and formulated into an sustained dosage form as an alternative to conventional tablet.