A High-Performance Liquid Chromatographic (HPLC) Method for the Determination of Amlodipine Drug in Dosage form Using 1,2-Naphthoquine-4-Sulfonate (NQS)

A rapid, simple and sensitive high-performance liquid chromatographic (HPLC) method for determination of Amlodipine (AML) using sodium 1,2-naphthoquinone4-sulfonate (NQS) has been developed. The method is based on the formation of a brown color product from the reaction between AML and NQS. The nucleophilic substitution reaction proceeds quantitatively at pH 13 buffer solution with absorption maximum at 465 nm. A C 18 column ODS (250mm×4.6mm), 5μm and a mobile phase of combination is potassium dihydrogen orthophosphate (0.05M) in water: acetonitrile (45:55%v/v) were used for separation and quantification. Analyses were run at a flowrate of 1.5mL/min and at 40 °C temperature. The injection volume was 20μL and the photodiode array detector was set at 465nm. Under these conditions Amlodipine-NQS eluted at 3.12 min. Total run time was shorter than 5 min. The developed method was validated according to the literature and found to be linear within the range 2-30μg /mL, describes by the regression equation y =207,082x +1,481.71 with a regression coefficient 0.999. The limit of detection and quantity are 0.01μg/mL and 0.04μg∕ mL respectively. This method is simple and can be applied for the determination of AML in pharmaceutical formulation in quality control laboratories.