Formulation and Evaluation of Pulsatile Drug Delivery System of Metoprolol Tartarate Using Core in Cup Tablet

The purpose of this work is to formu late a pulsatile drug delivery system using metoprolol tartarate as model drug. A core in cup (three component tablet) is prepared where in core tablet, an impermeable material surrounding the tablet except the top and soluble hydrophilic poly mer layer at the top is designed. The core tablet contains metoprolol tartarate, cellu lose acetate propionate is used as impermeable memb rane and sodium alginate 500 cps and sodium alginate 2000 cps used as soluble hydrophilic poly mer layer .The top cover layer is prepared using 3 2 factorial design. Quantification of water uptake, top layer expansion, in-v itro dissolution studies, radial and axial expansion, stereomicroscopic image, and short term stability studies are performed. The concentration of top layer of hydrophilic poly mer is a critical factor governing the release pattern, increase in the concentration increased lag t ime and delay the release .The T70% and T90 % values are also influenced by the polymer concentration with less polymer concentration of hydrophilic poly mer lesser T70% and T90 % values are obtained and as the concentration increased higher values are obtained. It can be concluded from the study that pulsatile drug delivery system useful in chronotherapy of hypertension can be prepared by this technique.