Investigations and HPLC Assay of Model Formulations Containing Amlodipine Besylate and Lisinopril

This paper describes the development and validation of a high-performance liquid chromatographic analytical procedure for simultaneous determination of Amlodipine Besylate (AML) and Lisinopril (LIZ) in model tablet formulations. The separation was achieved with a C18 (250 mm x 4.6 mm, 10 µm) column, at room temperature in an isocratic mode, with the mobile phase containing acetonitrile and 0.5 M sodium acetate buffer (25:75). The flow rate was 1.5 ml/min and the eluent was monitored at 215 nm. The selected chromatographic conditions were found to effectively separate Amlodipine Besylate and Lisinopril, with retention times of 6.67 min and 12.00 min, respectively. The method was validated for specificity, linearity, precision, accuracy, LOD and LOQ. The calibration curves were linear in the concentration range of 5.00-40.00 µg/ml for both AML and LIZ. The intra- and inter-day relative standard deviations for both the components were <2.0 %. The analytical procedure was applied in identification, purity and assay tests on model drug formulations. It was established that the developed analytical procedure was successfully used for routine analysis of AML and LIZ in model drug dosage forms without any interference from included excipients.