Drug binding defect of uraemic plasma: unlikely involvement of carbamoylated albumin.

Carbamoylation of bovine and human albumin in vitro decreased the binding of methyl red and salicylic acid. Charcoal extraction of the carbamoylated albumin under acid conditions produced some decrease in the degree of carbamoylation, but did not substantially improve the binding of methyl red and salicylate. Albumin from rats with glycerol-induced renal failure showed no significant degree of carbamoylation compared to controls. Carbamoylation is not responsible for the binding defect of uraemic rat plasma, nor is likely to be involved in the case of human uraemic plasma.