Simultaneous Determination of Amlodipine Besylate and Benazepril Hydrochloride in Pharmaceutical Dosage Form by LC

A rapid, precise, specific, and accurate ultra performance liquid chromatography (UPLC) method has been developed and subsequently validated for simultaneous determination of amlodipine present as amlodipine basylate (AB) and benazepril hydrochloride (BH) in capsule dosage form. The chromatographic separation was achieved on an Acquity UPLC, BEH C8 (100 mm × 2.1 mm, 1.7 μm) column using a photodiode array detector. The mobile phase used consisted of a mixture of phosphate buffer pH 3.0 (0.01 M aqueous potassium dihydrogen phosphate, pH 3.0 adjusted with orthophosphoric acid) and solvent mixture (equal mixture of acetonitrile and methanol) in the ratio of 45:55 (v/v) at a flow rate of 0.3 mL/min. The described method was linear over ranges of 5.21 − 15.63 μg/mL for AB and 20.24 − 60.72 μg/mL for BH. The mean recoveries were 100.47 and 99.97% for AB and BH, respectively. The lower limit of quantification was determined on the basis of signal-to-noise ratio method; it is 0.01 μg/mL for AB and 0.019 μg/mL for BH.