Alteration of plasma albumin in relation to decreased drug binding in uremia.

The binding of sulfadiazine in the plasma of normal and uremic subjects was measured by means of an ultrafiltration technique. Patients with uremia had reduced binding of sulfadiazine due to decreased albumin-binding capacity. No conclusive evidence was found to suggest that reduced drug binding in uremia is caused by competing metabolites. Studies of purified normal and uremic albumin revealed differences in amino acid composition and variations in the protein content of the two albumin bands found on isoelectric focusing. It is suggested that decreased drug binding in uremia may be at least partly due to altered albumin composition.