Binding of certain acidic drugs to human albumin: Theoretical and practical estimation of fundamental parameters

Summary The binding to human albumin of four acidic drugs, acenocoumarin, sodium chlorophenoxyisobutyrate, phenylbutazone and warfarin, has been measured by equilibrium dialysis and ultrafiltration at 37°C and pH 7.4. The affinity constants and numbers of binding sites for each drug were then calculated according to the law of mass action. With the aid of these values, it was possible to estimate the percentage binding of each drug after a therapeutic dose and assuming an albumin concentration of 40 g/l. The results obtained were identical to those previously measuredin vivo.