Microcalorimetric investigations of drug-albumin interactions.

Flow microcalorimetry was used to estimate primary binding constants for drug-albumin interactions. Measurements of heat of reaction at two temperatures illustrated the danger of extrapolation for pharmacokinetic purposes of measurements made at temperatures other than 37 degrees. The method could be used to predict competition between two drugs for a single binding site. Major advantages over spectroscopic techniques included direct determinations of thermodynamic parameters, and the use of physiological concentrations of albumin.