Fabrication a novel ethylenediamine sulfonamide polymer resin and graphene-modified carbon paste electrodes for simultaneous determination of anti-HBV drugs entecavir and tenofovir in dosage form by differential pulse voltammetry

The combination of entecavir (ETV) and tenofovir (TEV), nucleos(t)ide analogs (NUCs), is advised as first-line treatment for people suffering from multidrug-resistant hepatitis B due to their favorable safety profile, low side-effect rate, and high genetic barrier. This study reports the fabrication of a novel cross-linked ethylenediamine sulfonamide polymer resin (EDASP) and graphene (Gr)-modified carbon paste electrodes (CPE) for the simultaneous determination of the anti-HBV drugs ETV and TEV in bulk and dosage form by differential pulse voltammetry (DPV). The electrodes were specified through cyclic voltammetry, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and the analytical parameters were optimized. The findings indicate that both drugs displayed clear oxidation peaks on the Gr-CPE and EDASP-CPE electrodes at pH 4.5 and 4.0, respectively, in the Britton-Robinson buffer. The linear dynamic range of ETV and TEV was determined between 1µM and 250µM on both working electrodes by DPV. The limit of detection (LOD) and limit of quantification (LOQ) for ETV were 0.2µM and 0.6µM, respectively, on Gr-CPE. The LOD and LOQ for TEV were 0.2µM and 0.7µM, respectively. The novel EDASP-CPE exhibited improved sensitivity with LOD and LOQ for ETV of 0.2µM and 0.5µM, respectively. The LOD and LOQ for TEV on EDASP CPE were 0.2µM and 0.7µM, respectively. The proposed method was successfully applied to the simultaneous determination of ETV and TEV in a commercial tablet dosage form, exhibiting good accuracy and precision. The results highlight the potential of the novel cross-linked ethylenediamine sulfonamide polymer resin-modified carbon paste electrode for the simultaneous determination of anti-HBV drugs in dosage form by differential pulse voltammetry.