Electrochemical oxidation behavior of ezetimibe and its adsorptive stripping determination in pharmaceutical dosage forms and biological fluids

Abstract

Ezetimibe (EZE) is a drug that reduces plasma cholesterol levels and performs by decreasing cholesterol absorption in intestines. In this study, we examined the electrochemical behavior of EZE on a glassy carbon electrode and optimum conditions for its quantitative determination by using voltammetric methods. In addition, some electrochemical parameters such as diffusion coefficient, surface coverage of adsorbed molecules, electron transfer coefficient, standard rate constant and number of electrons were calculated by using the results of cyclic voltammetry. A tentative mechanism for the oxidation for EZE is suggested. As a result of bulk electrolysis and cyclic voltammetric experiments, an intermediate product occurred. The oxidation signal of the EZE molecule was used to develop fully validated, new, rapid, selective and simple square-wave anodic adsorptive stripping voltammetric (AdsSWV) and differential pulse anodic stripping voltammetric (AdsDPV) methods to direct determination of EZE in pharmaceutical dosage forms and biological samples. As a result of these studies, for the AdsDPV and AdsSWV techniques, linear working ranges were found to be 4.0 × 10⁻⁷–7.6 × 10⁻⁶ and 4.0 × 10⁻⁷–6.0 × 10⁻⁶ mol L⁻¹, respectively. The detection limits obtained from AdsDPV and AdsSWV were calculated to be 1.529 × 10⁻⁷ and 1.185 × 10⁻⁷mol L⁻¹, respectively. Moreover, the limit of quantification was evaluated for AdsDPV and AdsSWV methods and found to be 5.098 × 10⁻⁷ and 3.951 × 10⁻⁷ mol L⁻¹, respectively. The developed methods for EZE were successfully applied to assay the drug in tablets, human blood serum and human urine.