Binding of diuretics to human serum albumin and to human serum from healthy adults and patients with renal failure.

Abstract

It was found by in vitro equilibrium dialysis method that there is a small difference in the binding percentage of three diuretics, hydrochlorothiazide, furosemide, and ethacrynic acid, to bovine serum albumin and that to human serum albumin (between two animal species). The binding of three diuretics to human serum was examined in healthy adults and in patients with renal failure. In the healthy adults, binding of three diuretics was dependent on the degree of dilution of human serum. The same type of binding percentage curves was obtained when crystalline human serum albumin and healthy adult serum were diluted with M/15 phosphate buffer. This fact may suggest the possibility that the albumin level in human serum was closely related to the diuretics binding process. In the renal failure, the binding of hydrochlorothiazide and furosemide was correlated with the albumin concentration in human serum. However, the renal failure had reduced the binding of ethacrynic acid due to decreased serum binding capacity. Calculation of binding percentages would be required to assess the clinical importance of decreased binding of diuretics to serum of patients with renal failure.