Formulation and in Vitro Evaluation of Stomach Specific Floating Microspheres of Simvastatin

Abstract

The overall prevalence of dyslipidemia in India in 2013 was 10 % to 73 %. The prevalence of hyperlipidemia is more in females (33.2 %) than in males (32.4). On an average 32.8 % population is suffering from hyperlipidemia. The objective of the present study is to prepare and evaluate the stomach specific floating microspheres of simvastatin. Simvastatin microspheres were prepared by ionotropic gelation method using polymers such as sodium alginate, guar gum, pectin and carbopol. Total 12 formulations were prepared by using the above polymers. The prepared microspheres were evaluated for their appearance, solubility, physical properties (bulk density, tapped density, compressibility index, angle of repose), particle size, swelling index, SEM studies, buoyancy property, entrapment efficiency, in-vitro dug release and drug release kinetics. All formulations showed compliance with pharmacopoeial standards. The in-vitro drug release studies were conducted using USP dissolution apparatus type II (paddle) in 900 ml of 0.1 N HCl for first 2 h, next 1 h in 6.8 pH phosphate buffer and the remaining 9 h in 7.4 pH phosphate buffer. Surface morphology (SEM analysis) was conducted with F2, F7, F10 and F12 formulations. Drug polymer interaction studies (FTIR) were performed with all the polymers. The microspheres were smooth and elegant in appearance, showed no visible cracks as confirmed by SEM and FTIR studies indicated the lack of drug polymer interaction. Based on dissolution data, formulation F12 was the best formulation with a drug release of 98.96 %. The in-vitro release data of all microsphere formulations were plotted in various kinetic equations to understand the mechanisms and kinetics of drug release. The drug release kinetics of formulation F12 was of zero order with non-fickian mechanism according to Korsmeyer-Peppas equation.