Electrooxidation of Some Antifungal Agents and Their Square-Wave Voltammetric Determination in Cosmetics and Pharmaceutics

Ketoconazole and methylparaben were electrochemically studied using cyclic and square wave voltammetric (SWV) techniques at glassy carbon electrode. The oxidation of methylparaben and ketoconazolethe mechanism under scrutiny in this studywas characterized by irreversibility and the features of a pH-dependent diffusion controlled process. Optimal conditions for the electrochemical behavior of methylparaben and ketoconazole were investigated [e.g., potential window, supporting electrolyte and potential scan rates, the dependence of current intensities and potentials on pH, the linear relationship between the peak current and the concentration, limit of detection (LOD), limit of quantification (LOQ), recovery, and accuracy]. The proposed procedures were used for the determination of studied substances in cosmetic and pharmaceutical samples for methylparaben and ketoconazole, respectively. The current-concentration plot for methylparaben was linear over the range from 1 center dot 10-5 to 2.02 center dot 10-4molL-1 in 0.1molL-1 HClO4. The linear response for ketoconazole was obtained in the range of 3.2 center dot 10-7-9.58 center dot 10-6molL-1 in NH3-NH4Cl buffer at pH 9. The repeatability and reproducibility of the methods for the studied substances were also determined. Furthermore, results obtained by the proposed methods have been compared with high-performance liquid chromatographic methods.