Simultaneous Determination of Ezetimibe and Simvastatin in Pharmaceutical Dosage form by Validated RP-HPLC and UV- Spectrophotometric Methods

A simple, rapid and precise method is developed for the quantitative simultaneous determination of Ezetimibe and Simvastatin in combined pharmaceutical-dosage forms. Two methods are described for the simultaneous determination of Ezetimibe and Simvastatin. The first method was based on UVSpectrophotometric determination of two drugs, using simultaneous equation method. It involves absorbance measurement at 228.8 nm (λmax of Ezetimibe) and 238.4 nm (λmax of Simvastatin) Methanol: Water (90:10); For UV Spectrophotometric method, linearity was obtained in concentration range of 2 – 18 μg/ml, for both the drugs; with regression 0.999 and 0.999, intercepts 0.004 and 0.005 and slope 0.040 and 0.062 for Ezetimibe and Simvastatin respectively. Recovery was in the range of 99 –107%; the value of standard deviation and % R.S.D. were found to be < 2 %; shows the high precision of the method.. The second method was based on HPLC separation of the two drugs in reverse phase mode using these C18, 4.5μ (250 X 4.6 mm). The accuracy and reliability of the method was assessed by evaluation of linearity (1-18 μg/spot for both Ezetimibe and Simvastatin), precision (intra-day and inter-day % RSD >2 for Ezetimibe and Simvastatin), accuracy (98-102% for Ezetimibe and Simvastatin) and specificity, in accordance with ICH guidelines. Both these methods have been successively applied to pharmaceutical formulation and were validated according to ICH guidelines.