Influence of antidepressant clomipramine hydrochloride drug on human serum albumin: Spectroscopic study

The interactions of serum albumins with a variety of drugs have expected immense interest currently owing to their considerable achieve in the biomedical area. In the current study, we have accounted the interactions between clomipramine hydrochloride (CLP) drug and human serum albumin (HSA) using various techniques such as UV-visible, fluorescence as well as circular dichroism (CD) at different temperatures (298.15, 310.15 and 318.15 K). CLP is a tricyclic antidepressant which is used to treat obsessive compulsive disorder. The outcomes of the current examination under the physiological circumstances suggested a static type of binding takes place between the CLP and HSA having binding constants of 104 L/mol. The evaluated thermodynamic parameters, inferred that reaction was an endothermic and spontaneous process, and hydrophobic together with electrostatic interactions are the main binding forces engaged in the formation of the HSA-CLP complex. According to Förster's theory, the distance (r0) between donor and acceptor was achieved to be 3.09 nm. The count of binding sites for binding of CLP on HSA was obtained to be around one. Adding of CLP causes the quenching of HSA fluorescence and a red shift at both excitation wavelengths (280 and 295 nm) owing to the hydrophobic interaction between drug and HSA. Circular dichroism (CD) spectra of HSA confirmed considerable alteration in the conformation of protein structure in the attendance of CLP. Therefore, the results obtained herein will be of biological importance in pharmacology as well as clinical medicine.