Development and optimization of metoprolol succinate gastroretentive drug delivery system

Metoprolol succinate (MS) gastroretentive (GR) controlled release system was formulated to increase gastric residence time leading to improved drug bioavailability. Box-Behnken model was followed using novel combinations of sodium alginate (SA), sodium carboxymethylcellulose (NaCMC), magnesium alumino metasilicate (MAS) as independent variables. Floating lag time (Flag), t(25), t(50), t(75), diffusion exponent as dependent variables revealed that the amount of SA, NaCMC and MAS have a significant effect (p < 0.05) on t(25), t(50), t(75) and Flag. MSGR tablets were prepared and evaluated for mass, thickness, hardness, friability, drug content and floating property. Tablets were studied for dissolution for 24 h and exhibited controlled release of MS with floating for 16 h. The release profile of the optimized batch MS01 fitted first- order kinetics (R-2 = 0.9868, n = 0.543), indicating non- Fickian diffusion or anomalous transport by diffusion and swelling.