This paper describes a simple, precise and accurate RP-HPLC method for simultaneous quantification of these compounds in the bulk drug and in tablet dosage forms. The chromatographic separation of the drugs were performed on X-terra C8 (4.6 x 250mm, 5mm), with Phosphate Buffer [pH 3.5 with Ortho Phosphoric Acid] – Acetonitrile 40:60 (v/v) as mobile phase. The detection was performed at 240 nm. The accuracy and reliability of the method was assessed by evaluation of linearity (5-25 μg/mL for both Atorvastatin calcium and Ezetimibe), precision (intra-day RSD 0.57% and inter-day RSD 0.13% for Atorvastatin calcium and intra-day RSD 0.56% and inter-day RSD 0.09% for Ezetimibe), accuracy (99.59% for Atorvastatin calcium and 98.98% for Ezetimibe), and specificity, in accordance with ICH guidelines. The drug solution was exposed to different stress conditions and the stressed samples were analyzed by the proposed method. The peak homogeneity data for the drugs were obtained by using PDA detector in the stressed sample chromatograms which demonstrated the specificity of the method for the estimation in the presence of degradants. Overall the proposed method was found to be suitable and accurate for the quantitative determination and stability study of the drug in Pharmaceutical dosage form. The method was effectively separated the drug from its degradation product and it was employed as a stability- indicating one.
