Some novel observations of a drug (indoprofen)--albumin interaction.

Indoprofen, a new-steroidal anti-inflammatory agent, binds to human serum albumin in an endothermic reaction at low degrees of saturation and with an exothermic reaction at higher drug to protein ratios. Although indoprofen appears to bind to the same primary site as diazepam, dialysis studies show an increased binding of both drugs in the presence of the other. This novel observation is probably due to the effect of the drugs on the N leads to B conformational change of human serum albumin.