To determine the binding properties of the test item to plasma proteins/isolated plasma protein fractions.
Equilibrium dialysis or ultrafiltration.
Blank plasma or solution of isolated plasma proteins are spiked with the test item at relevant concentration levels and dialyzed at physiological temperature or incubated at physiological temperature prior to ultrafiltration.
Bioanalysis: the test item concentrations are quantified in the initial samples and in the dialyzates or in the ultrafiltrates.
Calculation of the plasma protein binding (%) and evaluation of its concentration dependency.