Indirect spectrophotometric determination of atenolol, isoniazid and pyridoxine hydrochloride using N-bromosuccinimide and neutral red dye

A simple and sensitive indirect spectrophotometric method was developed for the determination of atenolol, isoniazid and pyridoxine hydrochloride in pharmaceutical preparations , the method depending on the oxidation of the studied drugs with an excess of N-bromosuccinimide in hydrochloric acid medium and the remaining instead left amount of oxidizing agent reacted with fixed amount of neutral red and bleaching its color of the dye neutral red which absorbs at 530 nm. Calibration graphs were linear over 0.3-13, 0.2-10, and 0.3-17.5 g/ml, with a molar of absorptivity 1.98104 , 1.88104, and 1.62104 l.mol-1.cm-1 for each of Atenolol, isoniazid, and pyridoxine hydrochloride, respectively. The average recovery was ranged between 99.89 and 100.45%, and RSD is less than 1.3%. The method was successfully applied for the determination of studied drugs in pharmaceutical preparations. The results were in a good agreement with the certified values, standard addition procedure and official of British Pharmacopoeia. It was found that the experimental values of t and F-test less than the tabulated values at 95% confidence level.