Preparation and statistical optimization of alginate based stomach specific floating microcapsules of simvastatin

The present study involves preparation and characterization of floating microcapsules with simvastatin as model drug for prolongation of gastric residence time. The main objective is to improve solubility of simvastatin beta-CD complex (1:2) by co-precipitation method and then to deliver the same in sustained release dosage form. Sustained-release simvastatin microcapsules were prepared by the ionic gelation technique, using carbopol 941 as swellable floating polymer. A 3(3) full factorial design was used to study the effect of polymer concentration, drug complex and sodium alginate by plotting main effect plot and 3D surface plots. The formed microcapsules were subjected to various evaluation tests such as drug encapsulation efficiency, in vitro drug release and surface morphology by scanning electron microscopy. Powdered X-ray diffractometry and FTIR were used to investigate the complexation of simvastatin in the microcapsules. As the carbopol 941 is self swellable polymer, immediate floating was observed. The in vitro release studies and floating behavior were performed in HCI buffer of pH 1.2. The release profile and dissolution kinetic showed that drug release from the microcapsules follows zero order kinetics. It was concluded from the present investigation that porous carbopol 941 microcapsules are promising sustained release system as well as stomach specific carriers for delivery of simvastatin.