Differential Pulse Cathodic Voltammetric Determination of Metopimazine in Dosage Forms through Treatment with Oxone

Abstract

A simple, rapid and sensitive voltammetric method for determining Metopimazine (MPZ) as its sulfoxide was developed. The Metopimazine sulfoxide derivative (MPZO) is formed quickly and quantitatively at room temperature by adding potassium caroate solution. Well-defined cathodic waves were obtained for MPZO in 0.02 mol/L HCl using the differential-pulse mode at the hanging mercury drop electrode (HMDE). It is shown that the limiting stage of the MPZO reduction process is the adsorption of MPZO on the electrode surface. Factors affecting the peak current were studied and optimised. The current–concentration relationship was linear over the 0.4-2.7 µg/mL ranges for MPZ, respectively. The technique has been developed and the possibility of quantitative determination of Metopimazine in Vogalene Lyoc 7.5 mg tablets by an indirect voltammetric method using potassium caroate (Oxone) as an oxidising agent has been shown. RSD was ≤1.63% (δ = –0.40…..–1.07%), where δ = (-µ)·100%/µ, and µ is the average value of the quantitative determination by reference spectrophotometric method. According to the data of the linear part of the calibration graph, the limit of detection (LOD) and the limit of quantification (LOQ) were calculated, which are 0.1 μg/mL and 0.4 μg/mL, respectively. The method is specific for an intact drug in the presence of oxidative and photochemical decomposition products and excipients.