261: Spectroscopic studies on the interaction of bovine (BSA) and human (HSA) serum albumins with Norclomipramine

Abstract: Understanding drug–protein interactions is fundamental to the development, optimization, and safe application of pharmaceutical agents. Norclomipramine, the primary active metabolite of clomipramine, is a clinically significant antidepressant widely prescribed for the treatment of obsessive–compulsive disorder (OCD). Investigating its interaction with serum proteins is essential for understanding its pharmacokinetic and pharmacodynamic behavior. This research aims to examine the binding behavior of norclomipramine with bovine serum albumin (BSA) and human serum albumin (HSA), two widely used model transport proteins, through spectroscopic techniques. Serum albumins play a critical role in drug transport and distribution in the bloodstream; therefore, characterizing their interaction with norclomipramine provides insight into the drug’s bioavailability, stability, and potential side effects. Fluorescence spectroscopy will be employed to monitor quenching behavior and conformational changes upon complex formation. Stern–Volmer analysis will be applied to determine the quenching mechanism and calculate thermodynamic parameters, including enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy change (ΔG). These parameters will help elucidate the dominant intermolecular forces governing the interaction, such as hydrogen bonding, hydrophobic interactions, van der Waals forces, and electrostatic forces. Additionally, fluorescence data will be used to determine the binding constant (Ka), the number of binding sites (n), and the binding distance between norclomipramine and the albumins through Förster resonance energy transfer (FRET) analysis. The findings of this study will provide a comprehensive understanding of the molecular binding properties of norclomipramine with serum albumins. Such insight contributes to a deeper understanding of its pharmacological behavior, therapeutic efficacy, and potential drug–protein interaction mechanisms, which are critical for drug design and clinical application.