Green Spectrophotometric Method for Determination of Mesalazine Drug by Oxidative Coupling Reaction with Phenoxazine

Abstract

A novel green, straightforward, and precise spectrophotometric method for determination of mesalazine drug has been developed. This method relies on an oxidative coupling reaction between mesalazine and the environmentally friendly phenoxazine reagent in an acidic medium within the presence of potassium iodate as an oxidizing agent. The resulting colored product exhibits maximum absorbance at 549 nm. The calibration graph was rectilinear over the range of 0.2-30 μg mL^-1 (1.31×10^-6-1.96×10^-4 mol L^-1) with coefficient of determination (R²) of 0.9994 and molar absorptivity of 4.8×10³ L mol^-1 cm^-1. The limits of detection and quantitation were found to be 0.191 and 0.638 μg mL^-1, respectively. The average recovery percentage was 100.9 with a relative standard deviation less than 3.1. The proposed method was effectively applied to determine mesalazine in tablet dosage forms from three different sources, yielding highly satisfactory results that closely align with the standard method outlined in the British Pharmacopeia