Stability Indicating RP-HPLC Method For Simultaneous Estimation of Ramipril and Amlodipine Besylate in Pharmaceutical Dosage Form

A simple and accurate stability indicating RP-HPLC method for the simultaneous estimation of Ramipril and amlodipine besylate in pharmaceutical dosage form was developed and validated. The separation of selected drugs was done by using, X-Bridge C18 (150 x 4.6 mm, 5μ) column as stationary phase and a mixture of 5 mM Ammonium acetate(45): ACN(55): 0.1%formic acid(0.5) as mobile phase. Flow rate of mobile phase was maintained at 1 ml/min at ambient temperature throughout the experiment. Quantification was achieved with ultraviolet (DAD) detection at 240 nm. The retention times of Ramipril and amlodipine besylate were found as 5.653minutes and 6.944 minutes respectively. The detector response was linear in the concentration range of 4–12μg/ml for both drugs and the regression coefficients found as 0.9999 and 0.9998 for Ramipril and amlodipine respectively. This method was found free of any interference from any excipients. The percentage recovery values for Ramipril and amlodipine was found to be in the range of 98.83–101.09% and 98.40–100.13%. The Ramipril and amlodipine subjected to stress conditions including acidic, alkaline, oxidation, photolysis and thermal degradation. Ramipril and amlodipine besylate were more sensitive towards alkali and oxidative degradation. The developed method has been optimized and validated according to ICH guidelines and shown to be Specific, Sensitive, Precise, Accurate, Rugged and Robust. Hence, this method can be applied for routine quality control of Ramipril and amlodipine besylate in dosage forms as well as in bulk drug.