Green Electrochemical Sensor for Determination of Betamethasone in Semi-Solid Pharmaceutical Formulations

Betamethasone (BMS), an important representative of the glucocorticoid class, is an active steroid compound with multiple therapeutic applications, including anti-inflammatory and immunosuppressive properties. For the determination of betamethasone in pharmaceutical semi-solid samples (gels) an electrochemical sensor based on sulphur doped graphene modified with zinc oxide (ZnO/Gr-S) was developed and analysed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Betamethasone was determined over a linear concentration range between 0.01 and 10.0 μmol l −1 , with a sensitivity of 1.16 μA μmol l −1 and a limit of detection of 0.003 μmol l −1 . Good selectivity was observed in the presence of interfering chemicals, along with good repeatability, reproducibility, and stability. The ZnO/Gr-S has been successfully used for the determination of betamethasone from a betamethasone-based gel, giving recovery values range between 97,66% and 102,03% and RSD values under 5%. The method was evaluated using the Green Analytical Procedure Index (GAPI), Analytical Greenness (AGREE), and Blu application Grade Index (BAGI) tools, indicating little environmental impact and significant application. This paper presents significant advancements in electrochemical sensing for BMS detection, offering a creative, sustainable, and pragmatic solution for practical applications.