Electrochemical investigation of buclizine: First mechanistic study of proton-coupled electron transfer at a glassy carbon electrode

This study reports, for the first time, the electrochemical oxidation behavior of buclizine at a glassy carbon electrode using cyclic and differential pulse voltammetry. The effects of solvent composition, methanol content, pH, supporting electrolyte, and scan rate on the oxidation process were systematically examined. Optimal electrochemical signals were obtained in Britton-Robinson buffer at pH 4.0 containing 10% (v/v) methanol. The oxidation peak potential shifted toward more negative values with increasing pH, with slopes close to 59 mV/pH in both voltammetric techniques, indicating that the oxidation involves equal numbers of electrons and protons. Scan rate studies combined with Laviron analysis confirmed that the oxidation proceeds via a single-electron transfer. Based on the experimental findings, an irreversible proton-coupled electron transfer mechanism involving one electron and one proton (1 e⁻ / 1 H⁺) was proposed. The findings in this article provide the first experimental information on the electrochemical oxidation pathway of buclizine, offering important data for understanding the chemical stability and pharmaceutical quality of the compound.