Abstract

KINETICS OF OXIDATION OF PHARMACEUTICAL DRUG METFORMIN HYDROCHLORIDE BY BROMAMINE –T IN NaOH MEDIUM. A MECHANISTIC STUDY

P. R. Rangaraju, T V Venkatesha* and R Ramachandrappa

ABSTRACT

The kinetics of oxidation of Metformin hydrochloride (MET) by bromamine-T (BAT) has been investigated in NaOH medium at 303 K. The reaction followed first-order kinetics with respect to [BAT], [MET] and fractional-order with [OH−]. First-order kinetics with respect to [BAT] was observed for the oxidation of metformin hydrochloride. An increase in medium concentration increased the rate of reaction. The effect of added halide ions, reduction product p-toluene sulfonamide (PTS), ionic strength (NaClO4) and dielectric constant of the medium was studied on the rate of reaction. The main products were identified by spot test, GC−MS spectral analysis. A mechanism was proposed on the basis of experimental results. The activation parameters have been determined from the Arrhenius plots. With respect to the slow step of the mechanism were evaluated, and the thermodynamic parameters was also determined and discussed.

Keywords: Kinetics, oxidation, Metformin hydrochloride , bromamine-T, mechanism.