Fluorometric study for the reaction between sertraline and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole: kinetics, mechanism and application for the determination of sertraline in tablets.

A fluorometric study has been carried out, for the first time, to investigate the reaction of the new generation antidepressant sertraline (SRT) with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl). In an alkaline buffered medium (pH 8.0), a green fluorescent product exhibiting maximum fluorescence intensity at 532 nm after excitation at 470 nm was produced. The factors affecting the reaction were carefully studied and the conditions were optimized. The kinetics of the reaction was investigated, the stoichiometry of the reaction was determined, and the mechanism was postulated. The activation energy of the reaction was determined and found to be 27.34 KJ mole(-1). Under the optimum reaction conditions, a linear relationship with good correlation coefficient (r = 0.9998, n = 6) was found between the fluorescence intensity of the reaction product and SRT concentrations in the range of 0.3-20.0 microg ml(-1). The limit of detection and limit of quantitation were 0.07 and 0.21 microg ml(-1), respectively. The intra- and inter-assay precisions were satisfactory; the relative standard deviations did not exceed 2.61%. The proposed method was successfully applied to the determination of SRT in its pharmaceutical tablets with good accuracy; the recovery percentages were 96.97-102.23 +/- 1.01-1.62%. The results were compared favorably with those of the reported method.