Insights into the Interaction of Dacarbazine and Human Serum Albumin from Electrochemical Probing

The interaction between dacarbazine (DAC) and human serum albumin (HSA) was investigated under physiological conditions using electrochemical techniques, including cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The CV results demonstrated that the oxidation of DAC on a pyrolytic graphite electrode (PGE) surface was irreversible and controlled by an adsorption-diffusion process. The addition of HSA was found to decrease the peak potential of DAC without altering the electrochemical parameters, which is likely due to the formation of an electro-inactive complex between the drug and protein, as supported by DPV and EIS measurements. Using DPV, the binding constant and stoichiometry of the complex were calculated to be 2.16 x 10(4 )mol(-1) l and 1:1, respectively. The temperature effect revealed that DAC binds to HSA through hydrophobic forces. In addition, the PGE electrode was successfully used to determine DAC in from biological samples.