Phenytoin binding to partially purified albumin in renal disease

Drug binding to protein is known to be altered in renal disease. Explanations include hypoproteinemia, competitive or noncompetitive inhibition, and basic functional defects in the binding protein. Albumin, the primary binding protein for phenytoin (DPH), was isolated from the plasma of patients with severe renal failure as well as from normal controls. DPH binding was not different between the albumin preparations isolated from the two sources, although some differences were detected in the apparent affinity constant and the number of binding sites. It would appear that the significant defect in DPH binding in renal disease cannot be attributed to a basic functional defect in the drug-binding protein albumin.