Indirect Spectrofluorimetric Method for Determination of Amlodipine besylate and Atenolol Using Acridine Orange Dye

A simple and highly sensitive fluorometric method was developed for the indirect determination of the two pharmaceutical compounds, amlodipine besylate and atenolol in pure form and in pharmaceutical tablets. The method was based on the principle of oxidation of the two drug compounds by adding a known excess of the oxidizing agent N-bromosuccinimide (NBS) in hydrochloric acid medium and reacting the remaining amount of the oxidizing agent with acridine orange dye, which was added in a fixed amount, and measuring the fluorescence intensity of the remaining dye at 530 nm with an excitation wavelength of 450 nm. It was found that the fluorescence intensity of the dye increased with increasing concentrations of the amlodipine besylate and atenolol within the range of 0.03-1.2 and 0.05-1.2 µg/ml for each of the two pharmaceutical compounds, respectively. The developed method gave good agreement and accuracy, as the average recovery   percentage ranged between 101.06 and 100.15% with a relative standard deviation of less than 2.3 and 3.5% for amlodipine besylate and atenolol, respectively.