Valproate plasma protein binding in the uremic condition.

The protein binding of sodium [carboxy-14C] valproate has been studied in normal and uremic plasma using the method of equilibrium dialysis. Protein binding was dependent on concentration in both cases but there was a marked reduction in binding capacity in patients with renal dysfunction. Treatment of normal plasma with urea or creatinine to reproduce concentrations observed in uremia induced small decreases in binding. Diffusion dialysis of uremic plasma partially restored the degree of binding. Pretreatment of uremic plasma with activated charcoal at pH 3 raised binding capacity to that of normal plasma.