Sensing of the COVID-19 antiviral molnupiravir in the presence of an anionic surfactant on the surface of a boron-doped diamond electrode in pharmaceutical formulation

This study explores the electroanalytical quantification of molnupiravir (MPV) through voltammetry, employing an unmodified boron-doped diamond electrode in the existence of sodium dodecyl sulfate (an anionic surfactant). MPV exhibited a distinct, irreversible oxidation peak at approximately + 1.1 V (vs. Ag/AgCl) in a 0.1 mol dm⁻³ HCIO₄ solution, as demonstrated by cyclic voltammetry. The results revealed that the anodic peaks of MPV are dependent on pH, with a range from 2.0 to 9.0. The addition of sodium dodecyl sulfate to the working electrolyte substantially elevated the oxidation peak currents of MPV. Using the square wave voltammetry, a satisfactory linearity was achieved in HCIO₄ at about + 1.1 V. The method demonstrated a linear response for MPV concentrations between 1.0 and 90.0 μg cm⁻³ (equivalent to 3.0 × 10^–6–2.7 × 10^–4 mol dm⁻³) and yielded a detection limit of 0.31 μg cm⁻³ (equivalent to 9.4 × 10^–7 mol dm⁻³). The proposed approach's applicability was assessed through the sensing of MPV in drug formulation. The results generated from the proposed approach for drug formulation samples were compared with those generated by the high-performance liquid chromatography method.