Simultaneous UV-Spectrophotometric Estimation of Rosuvastatin & Ezetimibe in Their Combined 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. Three new, simple, accurate and precise UV spectrophotometric methods have been developed and validated for the simultaneous determination of Rosuvastatin (RSV) and Ezetimibe (EZE) in their combined dosage forms. First method is based on Q‐absorption Ratio method using two wavelengths, 232.4 nm (λmax of EZE) and 237 nm (Isoabsorptive point). The second method is the dual wavelength method, where 226.4 nm and 239.2 nm were selected as λ1 and λ2 for the determination of Rosuvastatin and 232.6 nm and 252.4 nm were selected similarly for the determination of Ezetimibe. The last method involves the use of First order derivative technique. Here 232.4 nm, the zero crossing point of Ezetimibe, was selected for the determination of Rosuvastatin and 223.4 nm, the zero crossing point of Rosuvastatin, was selected for the determination of Ezetimibe. Methanol was the solvent used in all three methods. Both drugs showed linearity in the range of 1‐25μg/mL in all the methods. All methods were validated statistically and recovery studies were carried out. All methods were found to be accurate, precise and reproducible. These methods were 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 methods herein described can be successfully applied in quality control of combined pharmaceutical dosage forms.