Characterization of interaction between antitumor drug 5-fluorouracil and human serum albumin by affinity capillary electrophoresis

The characterization of interaction between antitumor drug 5-fluorouracil (FU) and human serum albumin (HSA) was studied by affinity capillary electrophoresis (ACE). The binding of FU drug to HSA at near-physiological conditions was evaluated. FU was found to show low affinity toward HSA, with binding constant of 9.19 × 10 4 M -1 . The thermodynamic parameters were obtained. The positive ∆H and ∆S values obtained by ACE showed that the binding reaction was an endothermic process, the entropy drived the binding, and hydrophobic interaction played major roles in the binding of FU to HSA. The replacement test with warfarin and ketoprofen showed that binding site of FU at the protein HSA is believed to be site I, it was in good agreement with those reported in the literatures. This study shows that affinity capillary electrophoresis analysis can be used to studying the binding of FU to the transport protein HSA. The data obtained in this paper helpe us in gaining some insights on a possible drug/protein interaction.