Stability-Indicating RP-HPLC Method For The Quantitative Determination Of Amlodipine Besylate And Lisinopril In Combined Antihypertensive Formulations

Abstract

A simple, accurate, and precise reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous estimation of Amlodipine Besylate and Lisinopril in fixed-dose combination formulations. Chromatographic separation was achieved using a C18 column (250 × 4.6 mm, 5 µm) with a mobile phase consisting of acetonitrile and phosphate buffer (pH 3.5) in the ratio of 60:40 v/v, at a flow rate of 1.0 mL/min. The detection was carried out at 210 nm using a UV detector. The retention times for Amlodipine Besylate and Lisinopril were found to be approximately 5.8 and 3.2 minutes, respectively. The method was validated according to ICH Q2(R1) guidelines for parameters including linearity, accuracy, precision, specificity, robustness, LOD, and LOQ. The linearity range was established between 2–12 µg/mL for Amlodipine and 5–30 µg/mL for Lisinopril, with correlation coefficients (r²) exceeding 0.999. Recovery studies demonstrated accuracy within 98–102% for both drugs. The method proved to be robust and suitable for routine quality control of the fixed-dose combination tablet containing Amlodipine and Lisinopril.