Plasma Protein Binding of Deramciclane in Different Species

Deramciclane is a novel structure among anxiolytic agents. Pharmacokinetic studies in different species indicated the possibility of strong protein binding. The binding of deramciclane to plasma from man, dog, rabbit, mouse and rat was investigated by equilibrium dialysis. Binding isotherms for human and dog plasma exhibited both saturable and non-saturable components, while binding to rabbit, rat and mouse plasmas appeared to be non-saturable. The differences could be attributed to the different α1-acid glycoprotein (AAG) affinities. The strong binding of deramciclane in human plasma (nK = 1.6 times 106 M−1) could be referred to the AAG component, and could be inhibited by several ligands known to associate with this protein. The high affinity and saturable binding of deramciclane to an acute phase component of the human plasma (AAG) necessitates careful dosage during therapeutic application.