Effect of sodium oleate on salicylic acid binding to human serum albumin.

The pharmacological activity of salicylates is related to the non-protein-bound fraction of drug in the plasma. Free fatty acids have been shown to displace bound drug and to increase the serum levels of salicylates. Continuous ultrafiltration was used to measure unbound salicylic acid at 37 degrees. A nonlinear analysis of the ultrafiltration data using whole number values for the number of binding sites indicates that sodium oleate displaces the salicylic acid competitively at both binding sites. Increased concentrations of fatty acids due to disease or the infusion of fatty acid emulsions perhaps may produce toxic levels of salicylic acid.