Alternative, Validated, Eco-Friendly Voltammetric Determination of Agomelatine in Synthetic Urine, Water, and Tablets

Agomelatine (AGO) is used to treat symptoms of depression and improve sleep quality. This study reports, for the first time, the electrochemical behavior and determination of AGO using a cathodically pretreated boron-doped diamond electrode (BDDE). Cyclic voltammetry revealed an irreversible oxidation peak of AGO at +1.24 V (<i>vs</i> Ag/AgCl) in phosphate buffer (pH 3.0). The peak current showed a linear relationship with AGO concentration over the range of 0.099 to 3.846 µmol L⁻¹, with a detection limit of 0.017 µmol L⁻¹. All analytical parameters were evaluated according to validation guidelines, confirming the method’s reliability and applicability. The proposed method was successfully applied to determining AGO in tablets, yielding results comparable to those obtained using a spectrophotometric method. The method was also tested in synthetic urine, river water, and tap water, with recovery rates ranging from 85.88–104.52%, 105.17–113.53%, and 86.79–119.52%, respectively. Additionally, the developed voltammetric method offers a more environmentally friendly alternative to existing approaches for AGO determination in the literature.