Method development and validation for the simultaneous determination of ramipril and cilnidipine by using RP-HPLC

A new reversed-phase HPLC method was developed and subsequently validated for simultaneous estimation of antihypertensive drugs Ramipril and cilnidipine in pharmaceutical dosage forms. Chromatography was carried out on Inertsil C-18 column (4.6 x 150mm, 5? particle size) with a mobile phase composed of Acetonitrile: K2HPO4 pH-2.5/OPA (30:70) and the mobile phase was pumped at a flow rate of 1.0 mL/min. Detection was carried out using a PDA detector at 225nm. Parameters such as linearity, precision, accuracy, recovery, specificity and ruggedness were studied as reported in the International Conference on Harmonization guidelines. The retention times for Ramipril and cilnidipine were 2.3 min and 3.7 min respectively. The linearity range for Ramipril and cilnidipine was 25-150 ?g/mL. The percentage recoveries of Ramipril and cilnidipine were 100.2% and 99.9%, respectively. This method can be employed for routine quality control of Ramipril and cilnidipine tablets in quality control laboratories and pharmaceutical industries.