Green analytical method for determination of oxeladin citrate using advanced electrochemical modified sensors in pure form, pharmaceuticals, human serum and binary mixtures with guaifenesin

This work presents a selective, accurate, and highly sensitive differential pulse voltammetric (DPV) approach for the quantification of oxeladin citrate (OC). The electrochemical behavior of OC was investigated using several working electrodes, including carbon paste electrode (CPE), zeolite-modified carbon paste electrode (ZMCPE), iron oxide-modified carbon paste electrode (IOMCPE) and screen-printed multi-wall carbon nanotubes (SPMWCNTs), with operational parameters optimized through cyclic voltammetry. The results confirmed an irreversible, diffusion-controlled oxidation process for OC producing a peak between 0.7 and 0.8 V (vs. Ag/AgCl). The SPMWCNTs electrode outperformed the others, providing a linear calibration range from 0.35 to 3.9 μg/mL (R² = 0.998), a detection limit (LOD) of 0.114 μg/mL, and a quantification limit (LOQ) of 0.35 μg/mL. The practical utility of the method was confirmed by the successful determination of OC in pharmaceutical products, both alone and in combination with Guaifenesin (GU), as well as in spiked human serum, all yielding excellent recovery values. The procedure's environmental footprint was critically evaluated using the Analytical Greenness Calculator (AGREE) and the Complex Green Analytical Procedure Index (Complex GAPI), with the high scores obtained verifying its eco-friendly nature. Characterized by its sensitivity, operational simplicity, and sustainability. This voltammetric strategy offers a robust and viable alternative for the routine analysis of OC in pharmaceutical quality control and clinical settings.