USING BENZIDINE REAGENT FOR SPECTROPHOTOMETRIC DETERMINATION OF MESALAZINE BY OXIDATIVE COUPLING REACTION

Abstract: A spectroscopic method has been developed to determine the mesalazine in both its pure form and pharmaceutical preparations. The procedure is characterized by its simplicity, rapidity, and high sensitivity. It relies on the oxidative coupling reaction between mesalazine and benzidine in the presence of ferric chloride as an oxidizing agent within a hydrochloric acid medium, leading to the formation of a brown-colored product exhibiting maximum absorbance at 480nm. The technique demonstrated adherence to Beer’s law over a concentration range of (1–15) μg.ml-1, with limits of detection (LOD) and quantification (LOQ) calculated at 0.0397 and 0.1323 μg.ml-1, respectively. The molar absorptivity was found to be 7.2×10³ L·mol⁻¹·cm⁻¹, while the recovery rate reached up to 100.65%. The technique could be effectively applied to the analysis of pharmaceutical dosage forms such as tablets and capsules.