Spectrophotometric Determination of Amlodipine Besylate Using 2-Hydroxynaphthaldehyde as a Derivatizing Reagent

Abstract

A new spectrophotometric method has been developed for the determination of the amlodipine besylate by derivatization with 2-hydroxy-naphthaldehyde. The molar absorptivity of amlodipine besylate after derivatization was calculated 1.05 ×10⁴ L mol^–1 cm^–1 at λmax 416 nm. The derivative obeyed the Beer’s law within the concentration range 4-20 μg/mL. The color reaction was highly stable and did not show any change in absorbance up to 12 h. The method was applied for the analysis of amlodipine besylate from tablets of various pharmaceutical companies and the amounts found were observed within 2.48, 4.95 and 9.97 mg/tablet with relative standard deviations (RSD) ranging 2.7-0.01 % (n = 3), respectively.