Voltammetric measurement of catechol-O-methyltransferase inhibitor tolcapone in the pharmaceutical form on the boron-doped diamond electrode

Musa Kiran; Yavuz Yardim

doi:10.55730/1300-0527.3650

Voltammetric measurement of catechol-O-methyltransferase inhibitor tolcapone in the pharmaceutical form on the boron-doped diamond electrode

Turk J Chem. 2023 Nov 2;48(1):184-194. doi: 10.55730/1300-0527.3650. eCollection 2024.

Authors

Musa Kiran¹, Yavuz Yardim²

Affiliations

¹ Department of Analytical Chemistry, Faculty of Chemistry, University of Van Yüzüncü Yıl, Van, Turkiye.
² Department of Analytical Chemistry, Faculty of Pharmacy, University of Van Yüzüncü Yıl, Van, Turkiye.

Abstract

This study presents an electroanalytical approach to measure the catechol-O-methyltransferase (COMT) inhibitor tolcapone (TOL) using a boron-doped diamond (BDD) electrode. The application of cyclic voltammetry (CV) technique revealed that TOL exhibited a distinct, diffusion-controlled, irreversible anodic peak at a potential of approximately +0.71 V (vs. Ag/AgCl) in a 0.1 mol L^-1 phosphate buffer solution (PBS) with a pH of 2.5. The oxidation of TOL is highly dependent on the pH and supporting electrolytes. Based on the data obtained from the pH investigation, a proposed mechanism for the electro-oxidation of TOL is suggested. Using the square wave voltammetry (SWV) technique, a satisfactory linear relationship was observed at approximately +0.66 V in a 0.1 mol L^-1 PBS with a pH of 2.5. The presented method exhibited linearity within the concentration range between 1.0-50.0 μg mL^-1 (3.7 × 10^-6-1.8 × 10^-4 mol L^-1), with a limit of detection (LOD) of 0.29 μg mL^-1 (1.1 × 10^-6 mol L^-1). The BDD electrode demonstrated good selectivity against inorganic ions and filler materials interference. Finally, the suitability of the developed approach was assessed by measuring TOL in tablet formulations, resulting in favorable recoveries ranging from 103.4% to 106.2%.

Keywords: Tolcapone; boron-doped diamond electrode; pharmaceutical form; voltammetric techniques.

Grants and funding

The authors would like to express their gratitude for the financial support provided by the Scientific Research Foundation of Van Yüzüncü Yıl University (project number: FDK-2021-9544).