RP-HPLC method for simultaneous estimation of atorvastatin calcium and ramipril from plasma

The combination of Atorvastatin Calcium and Ramipril is used in treatment of hypertensive disorders. It was necessary to develop simple, accurate, precise, selective and sensitive RP-HPLC method for the simultaneous estimation of atorvastatin and ramipril from plasma. The determination was carried out on a HIQ SII C18 column -10 (4.5 mm x 250 mm). column using a mobile phase of acetonitrile: 0.02 M Potassium dihydrogen phosphate (pH 3.2) [80: 20% V/V]. The developed method was validated by USFDA guidelines for bioanalytical methods. The retention time for atorvastatin was 6.42 min, for ramipril 3.43 min. Atorvastatin and ramipril showed a linear response in the concentration range of 0.4-25.6 mu g/ml and 0.8-51.2 mu g/ml respectively. The LOD and LLOQ values for Atorvastatin were 0.13 mu g/ml and 0.40 mu g/ml, for Ramipril 0.29 mu g/ml and 0.79 mu g/ml respectively. The intraday and inter-day precision studies and stability studies have shown applicability of method for extended period of time. Thus developed RP-HPLC method is found to selective and sensitive for the simultaneous estimation of both drugs in field of pharmacokinetics and bioequivalence studies.