Spectrophotometric Study of Oxidation Kinetics and Mechanism of Losartan Potassium Using N-chlorosuccinimide

The kinetics of oxidation of Losartan Potassium [LP] by N-Chlorosuccinimide [NCS] in HCl medium is studied spectrophotometrically at 205 nm at 298 K. The reaction rate shows fractional order dependence on [LP], [HCl] and first order dependence on [NCS]. The reaction rate also shows an inverse fractional order in [Cl-]. Addition of reduction product did not have any significant effect on reaction rate. However, an increase in ionic strength decreases and increase in solvent polarity increases the reaction rate. The activation parameters for the reaction are evaluated. The proposed general mechanism and derived rate law are consistent with observations.