Voltammetric sensor for COVID-19 drug Molnupiravir on modified glassy carbon electrode with electrochemically reduced graphene oxide

Abstract

• There are no published reports for electrochemical determination of Molnupiravir in any matrix. • The first electrochemical validated, sensitive, cheap, easy and fast method for determination of Molnupiravir in pharmaceutical preparations. • Reduced GO has excellent conductivity, thermal and chemical stability for sensor application. A direct, simple, and sensitive method based on electrochemical deposition of reduced graphene oxide (rGO) on a glassy carbon electrode (GCE) using cyclic voltammetry (CV) was developed for Molnupiravir (MOL) quantitative analysis. Here, the electrochemical oxidation of MOL was examined using square wave voltammetry (SWV) and a well-defined peak at 0.2 V was measured against the Ag/AgCl reference electrode with the rGO sensor in Britton-Robinson pH 9 buffer. Various operational parameters for MOL analysis such as pH of supporting electrolyte, instrumental parameters, electropolymerization cycles, and GO concentration were optimized. The sensor exhibited a linear range from 0.09 to 4.57 μM with a detection limit of 0.03 µM. The electrochemical response of the rGO sensor was characterized by electrochemical impedance spectroscopy and CV. The character of current and reversibility of the electrode reaction, the number of electrons and protons transferred were studied by the CV method. The developed sensor was validated according to the International Council for Harmonisation (ICH) guidelines. Validation parameters, such as stability, linearity, sensitivity, accuracy, precision, recovery, robustness and ruggedness were evaluated according to the ICH requirements. The developed sensor was successfully applied for the quantification of MOL in capsule formulations.