Determination of Thermodynamics Constant of Interaction among of Atenolol and Metoprolol with Human Serum Albumin: Spectroscopic and Molecular Modeling Approaches

Interaction of atenolol (Atn) and metoprolol (Met) beta-blocker drugs with human serum albumin (HSA) at pH 7.4 was investigated by UV-Vis spectroscopy and molecular modeling methods. In addition, the binding interaction information of Atn and Met with HSA practicaly of binding constant (K-b) were determined by the UV-Vis absorption titration at body actual temperature (310.15 K), and were found to be 9.5 x 10(3), 1.4 x 10(4), and 2.3 x 10(4) M-1 for Atn, Met, and Atn + Met, respectively. The results indicated that addition of Atn in many concentrations causes decrease, while addition of Met and Met + Atn leads to an increase in absorption upon complexation with HSA. The binding mechanisms of two target drugs are different from each other, as indicated by spectroscopic analysis. The results show that interactions in all systems are exothermic with negative entropy, which lead to more spontaneous reaction at lower temperatures. Molecular dynamics simulation calculations show that the number of interactive residues between Met and protein is less than the number of interactive residues between Atn and protein.