The use of charge-transfer complexation in the spectrophotometric determination of Amlodipine Besylate

A simple and sensitive analytical method has been developed for the spectrophotometric assay of amlodipine besylate (ADB) in pure forms and tablets have been described. The method is based on the formation of a charge-transfer complex between the drug and tetrachloquinone (TCQ). This complex exhibit intense absorption bands in the electronic spectrum. The molecular ratio of the reactant in the complex was established and the experimental conditions leading to maximum charge-transfer band was also studied. The reaction proceeds quantitatively at pH 9 and 55°C for 10 min, the absorbance was measured at 346 nm. The method was applied to commercially available tablets and the results were statistically compared with those obtained by UV spectrophotometric method, using Newman-Keuls tests. In our method, Beer's Law limits to 5-25 μg/ml. The optimum experimental parameters for colour production with reagent were studied and incorporated into procedure.