Permanganate Oxidation of Sulfadiazine: Analytical Method Development and Kinetic Study

Abstract

A multi-disciplinary approach has been made in this article where, the oxidation reaction of permanganate and sulfadiazine has been used to develop analytical method to quantitate the drug and the second part is the kinetic study of the oxidation reaction. The estimation of the drug is made at 602 nm. The developed method has been validated as per the international conference on harmonization (ICH) guidelines. The regression treatment of the linearity data yielded the linear regression equation A=0.00786+0.0184 C. Limit of detection and limit of quantitation was found to be 2.33 and 7.065, respectively. Since, the reaction proceeded such that the absorbance increased with increase in time, kinetic study of the reaction was performed. The kinetic parameters were performed at 602 nm. The reaction obeyed pseudo first-order kinetics in [alkaline KMnO4] and fractional order in [sulfadiazine]. The oxidation reaction was carried out at varied temperatures viz. 25, 30, 35, 40 and 45 (±0.1°C). On the basis of the observed results, mechanism of the reaction has been proposed. Activation parameters such as energy of activation, enthalpy, entropy and Gibbs free energy were determined and found to be 8.73 (kJ mol-1), 77.57 (kJ mol-1), 173 (JK-1 mol-1), 25.99 (kJ mol-1) respectively.