[The effects of various drugs on the binding site of bilirubin in serum albumin].

In the presence of various drugs, the concentration of free bilirubin which was released from the first binding site of bilirubin in serum albumin was evaluated, using a sensitive method based on static fluorescence quenching of dansyl serum albumin. Bilirubin bound to human serum albumin more strongly than to bovine serum albumin. Non-steroidal anti-inflammatory drugs, fenamates and allylphenyl propionic acids, affected the bilirubin-serum albumin interaction. Flufenamic acid and ketoprofen released bilirubin from human serum albumin. The bilirubin bound to the serum albumin was not influenced by the presence of indomethacin, but clidanac strongly dissociated bilirubin from the bilirubin-serum albumin complex. Sulfa-drugs, antibiotics, steroidal agents, warfarine, tolubutamide and phenytoin showed no significant effects on the bilirubin-serum albumin interaction. The fluorescence quenching method may be useful to evaluate the interaction of drug-bilirubin-serum albumin.