Studies on coumarin anticoagulant drugs. Heat of interaction of sodium warfarin and human plasma albumin by heatburst microcalorimetry.

The heat of interaction of sodium warfarin and human plasma albumin has been studied by heatburst microcalorimetry. Sixteen experiments were performed at warfarin concentrations of 0.02 and 0.10% and albumin concentrations of 0.2 and 0.4%. The average heat evolved was -3.14 kcal per mole of warfarin. It is suggested that the molecular basis of the warfarin-albumin interaction is hydrogen and hydrophobic bonding. Microcalorimetry was an ideal method for studying this interaction; the lack of specificity of the thermal method should allow its application to a wide variety of interactions of biological interest.