Simultaneous Estimation of Rosuvastatin & Ezetimibe by Ratio Spectra Derivative Spectrophotometry Method in Their Fixed Dosage Forms

Abstract

Rosuvastatin is an HMG Co-A inhibitor and Ezetimibe is an intestinal cholesterol absorption inhibitor. The combination formulation is used for the treatment of hypercholestrolemia. The Ratiospectra derivative spectrophotometric method was developed for the simultaneous determination of Rosuvastatin (RSV) and Ezetimibe (EZE) in their fixed dosage forms. The method depends on the use of the first derivative of the ratio-spectra obtained by dividing the absorption spectrum of binary mixtures by a standard spectrum of one of the compounds. The first derivative amplitudes at 237.4 and 223.4 nm were selected for the determination of RSV and EZE respectively. The wavelength interval (Dl) was selected as 4 nm. Methanol was used as the solvent. Both the drugs showed linearity in the range of 2.5-15μg mL-1. The method was validated statistically and recovery studies were carried out. It was found to be accurate, precise and reproducible. The method was applied to the assay of the drugs in marketed formulation, which were found in the range of 98.0% to 102.0% of the labeled value for both Rosuvastatin and Ezetimibe. Hence, the method herein described can be successfully applied in quality control of combined pharmaceutical dosage forms. Keywords: Rosuvastatin, Ezetimibe, Ratio Spectra Derivative Spectrophotometry.