Extended Release Formulation of Metoprolol Succinate Using Ion Exchange Technology

The purpose of this research work was to prepare an extended release formulation of metoprolol succinate using Ion exchange resin. Metoprolol succinate has short half life of 3-7 hours. So it needs to be administered 3-4 times a day. Hence an extended release preparation is desired. Drug-resin complex (DRC) was obtained by loading metoprolol succinate onto a strong cation exchange resin, Indion 244 in the ratio 1.5:1 using batch method. The molecular properties of the complex were investigated by differential scanning calorimetry, X-ray powder diffraction and Infra red spectroscopy which revealed interaction of drug with resin. To achieve the desired release rate, the DRC was initially treated with an impregnating agent, polyethylene glycol (PEG) 4000 and was further treated with hydrophobic polymer ethyl cellulose. Various formulations of tablets using resinate were prepared to achieve desired drug release profile. The formulations were evaluated for hardness, friability, weight variation, in vitro release and assay using HPLC. Formulation (V) shows optimum results in terms of release profile, which were in accordance with the USP specifications. The in vitro release profile showed that complexation of drug with ion exchange resin and use of hydrophobic polymer matrix could retard the initial burst and extend the release of drug up to 24 hours.