Development and Validation of Fast and Robust Stability Indicating RP-HPLC Method for Simultaneous Estimation of Azilsartan Medoxomil and Cilnidipine in Pharmaceutical Dosage Form

Objectives: A selective, precise and accurate RP-HPLC stability indicating assay method has been developed for the simultaneous estimation of Azilsartan medoxomil and Cilnidipine in tablet dosage form. Materials and Methods: The efficient chromatographic separation of drug was achieved by using C18 (150mm×4.6mm, Agilent 5μm) Column at ambient temperature. Mobile phase contains triethylamine buffer (pH 3.5 adjusted with ortho-phosphoric acid) and acetonitrile (40:60 V/V). Flow rate of mobile phase 1.0 ml/min using isocratic mode .Wavelength selected at 249 nm by using photo diode array detector. Results: The retention time of Azilsartan medoxomil peak 1, Azilsartan medoxomil peak 2 and Cilnidipine were noticed to be 2.16 min, 3.90 min and 9.52 min respectively. The linearity range for Azilsartan medoxomil and Cilnidipine were found to be 50 -150 μg/ml and 12.5-37.5 μg/ml and percent recoveries were noticed to be 99.27±0.58 and 98.65±0.49 respectively. Various stress testing conditions such applied to the drug ingredients and drug formulation. The degradants and drugs efficiently separated by using enhanced chromatographic conditions. The developed method was validated as per recommendation parameters of International council on harmonization guideline Q2(R1). Conclusion: The validation parameters stated that the drug substances were efficiently separated from its degradants and developed method can be routinely applied for the simultaneous estimation of Azilsartan medoxomil and Cilnidipine in tablet formulation in a laboratory.