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

The purpose of this work is to formulate 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 polymer layer at the top is designed. The core tablet contains metoprolol tartarate, cellulose acetate propionate is used as impermeable membrane and sodium alginate 500 cps and sodium alginate 2000 cps used as soluble hydrophilic polymer layer .The top cover layer is prepared using 32 factorial design. Quantification of water uptake, top layer expansion, in-vitro dissolution studies, radial and axial expansion, stereomicroscopic image, and short term stability studies are performed. The concentration of top layer of hydrophilic polymer is a critical factor governing the release pattern, increase in the concentration increased lag time and delay the release .The T70% and T90 % values are also influenced by the polymer concentration with less polymer concentration of hydrophilic polymer 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.