CORTICOSTEROID BINDING TO BLOOD PLASMA PROTEINS, A MICROCALORIMETRY AND SPECTROSCOPY STUDY

Characterization of drug binding to human blood plasma proteins is of essential importance for a better understanding of drug absorption, distribution and turnover in the circulation. Albumin, the most prominent protein in the plasma, plays fundamental role in the transport of drugs. Binding of a drug to albumin is a key factor controlling the kinetics and efficacy of drug transport in the blood. Dexamethasone is a well-known corticosteroid hormone, used to treat various diseases and allergic states. Using DSC, ITC, spectrofluorescence and UV-Vis spectroscopy, here we set out to characterize the dexamethasone interactions with blood plasma proteins, specifically with albumin, in simulated physiological conditions. The results obtained with the different methods revealed an exothermic process of preferential dexamethasone binding with albumin, with the likely involvement of hydrophobic forces in the dexamethasone-albumin complex formation. These findings provide new insights regarding the mechanism of corticosteroid transport and disposition in the circulation.