Development and Validation of RP-HPLC Method for Simultaneous Estimation of Enalapril Maleate and Amlodipine Besylate in Combined Dosage form

A simple, precise and rapid reverse-phase HPLC method has been developed and subsequently validated for the simultaneous estimation of Amlodipine besylate and Enalapril maleate from their combination drug product. The proposed RP-HPLC method utilizes a Phenomenex C18, 5 µm, 250 mm × 4.6 mm i.d. column, at ambient temperature, optimum mobile phase consisted of Methanol: Acetonitrile : Water (40:50:10, v/v/v), effluent flow rate monitored at 1.0 mL min-1, and detection using PDA detector. The described method was linear over the range of 0.5-6.0 g/ml and 0.5-8.0 g/ml for Enalapril maleate and Amlodipine besylate, respectively. The mean recovery was found to be 100.06 ± 0.49 % and 99.98 ± 0.63 % for Enalapril maleate and Amlodipine besylate, respectively. The intermediate precision data obtained under different experimental setup, the calculated value of coefficient of variation (CV, %) was found to be less than critical value. The proposed method can be useful in the quality control of bulk manufacturing and pharmaceutical dosage forms.