Optimization of Coating Formulation of Sustained Release Pellets of Metoprolol Tartrate by Central Composite Design-Response Surface Methodology

OBJECTIVE To prepare a twice daily sustained release pellets of Metoprolol Tartrate with blends of Eudragit RS 30D and Eudragit RL 30D as sustained coating material and optimize the coating formulation with central composite design-response surface methodology.METHODS Drug release from the coated pellets after 1,4 and 8 h were used as responses and central composite design-response surface methodology was applied to optimize sustained coating formulation,namely Eudragit RS 30D/Eudragit RL 30D ratio in sustained coating material and polymer load(weight gain),which were based on single factor tests.RESULTS Using similarity factor(F2),the dissolution profiles of three batches were found to be similar with the expected target profile.CONCLUSION Central composite design-response surface methodology can be applied to optimize the coating formulation for Metoprolol Tartrate sustained release pellets and the models developed in this study are proved to be predictable and feasible.