Spectroscopic Characterization on the Interaction Between Synthesized Platinum(II)-Based Drug and Human Serum Albumin

Abstract

The interaction of a new organoplatinum(II) complex [Pt(pr-dtc)(bpy)]NO3 (where pr-dtc = propyldithiocarbamate and bpy = 2,2′-bipyridine), as anticancer agent with human serum albumin (HSA) in aqueous solution at pH 7.4 has been studied by fluorescence, UV–Vis absorption, and CD spectroscopy. The quenching constants and binding parameters were determined by fluorescence quenching method. The obtained results revealed that there is a strong binding interaction between Pt(II) complex and HSA. The calculated thermodynamic parameters (ΔG, ΔH, and ΔS) confirmed that the binding reaction is mainly entropy driven, and hydrophobic forces played a major role in the reaction. The binding distance (r) between the Pt(II) complex (acceptor) and HAS (donor) was obtained based on Forsters theory of non-radiation energy transfer. Finally, the results of CD and UV–Vis spectroscopy showed that the binding of this complex to HSA induced conformational changes in protein. We hope that such spectroscopic studies will indeed be helpful in studying the pharmacological response of drugs and design of dosage forms.