Kinetics and Mechanism of Oxidation of Gabapentin (Neurontin) Anion by Alkaline Diperiodatonickelate(IV) — A Free Radical Intervention

Abstract

The kinetics of oxidation of gabapentin (Neurontin) (GP) by diperiodatonickelate(IV) (DPN) in aqueous alkaline medium was studied spectrophotometrically. The reaction is first order with respect to [DPN] and is an apparent less than unit order, each in [GP] and [alkali] under the experimental conditions. Reaction rate increases with increase in ionic strength and in solvent polarity of the medium. Addition of reaction products has no effect on the reaction rate. A mechanism involving the formation of a complex between the oxidant and substrate has been proposed. The products are identified by spot test, IR and NMR studies. The reaction constants involved in the mechanism were evaluated. There is a good agreement between the observed and calculated rate constants under varying experimental conditions. The activation parameters with respect to the slow step of scheme were evaluated and discussed.