Stereoselective effect of warfarin and bilirubin on the binding of 5-(o-chlorophenyl)-1,3-dihydro-3-methyl-7-nitro-2H-1,4-benzodiazepin-2- one enantiomers to human serum albumin.

The binding of the title benzodiazepine enantiomers and its modulation by warfarin and bilirubin were studied by chromatography on human serum albumin (HSA) immobilized on Sepharose 4B, and also by a combination of ultrafiltration and circular dichroism (UF-CD) methods. In the absence of warfarin and bilirubin the binding of the benzodiazepine was not stereoselective. (S)-Benzodiazepine and (S)-warfarin mutually increased the binding of each other, while the binding of (R)-benzodiazepine was preferentially enhanced on HSA saturated with bilirubin.