In this study, the interaction between sertraline hydrochloride (SRH), an antidepressant drug, and human serum albumin (HSA) in a physiological buffer was investigated using UV–Vis spectroscopy, equilibrium dialysis, fluorescence emission spectroscopy, circular dichroism, Fourier transform infrared (FT-IR) spectroscopy, and molecular docking methods. The results showed that SRH induced fluorescence quenching of HSA through a mixed mechanism. The drug-protein binding process was a cooperative binding pattern, as confirmed by the Scatchard plot and Hill coefficient. Molecular docking results demonstrated that SRH preferentially binds to site I in subdomain IIA of HSA, where Trp-214 is located, as confirmed by fluorescence analysis. Additionally, the binding constant (Kb), number of binding sites (n), and thermodynamic parameters showed that the binding of SRH to HSA was spontaneous, and that hydrophobic interactions were the main forces of this interaction. Furthermore, the results showed a conformational change in HSA upon interaction with SRH, as revealed by UV–Vis, circular dichroism, and Fourier transform infrared spectroscopy.
