Binding of Salicylate and Sulfathiazole by Whole Blood Constituents

The binding of salicylic acid and sulfathiazole to bovine whole blood, plasma proteins, and purified albumin fraction was investigated using a dynamic dialysis system. The binding profiles for salicylic acid were quite similar in bovine plasma and 4% bovine serum albumin. In contrast, the binding of sulfathiazole was significantly greater in the plasma than in solutions of fraction V bovine serum albumin. Data from dynamic dialysis binding studies of the compounds, conducted in whole blood and suspended erythrocyte systems, did not lend themselves to analysis by classical methods. Hemolysis and alteration in the nature of the protein binding sites during the binding studies were shown to be factors that could explain the unusual binding observed in the whole blood system.