PROTEIN-BINDING OF 2-CHLORO 2'-DEOXYADENOSINE (CLADRIBINE) IN HEALTHY-SUBJECTS AND IN PATIENTS WITH LEUKEMIA

The plasma protein binding of 2-chloro-2'-deoxyadenosine (CdA) at 37 d egrees C was studied by ultrafiltration in 5 healthy volunteers, in 11 patients with haematological malignancies and in purified protein pre parations. In the patients, the binding of CdA to plasma proteins was 25.0% and in healthy subjects it was 21.1%. In a solution of human ser um albumin (40 g.l(-1)), 24.3% CdA was bound, but less than 5% was bou nd in a solution of alpha(1)-acid-glycoprotein (0.7 g.l(-1)). No depen dence of binding on the concentration of CdA was found within a range 25-1000 nmol.l(-1). In conclusion, due to its limited binding to plasm a proteins, any change in the binding of CdA is unlikely to have a maj or influence on its pharmacological effect.