BINDING-KINETICS OF BUDESONIDE TO THE HUMAN GLUCOCORTICOID RECEPTOR

Glucocorticoid receptor-ligand binding kinetics of budesonide, a gluco corticoid used for inhalation therapy, were determined and compared wi th dexamethasone and fluticasone propionate using glucocorticoid recep tors from human lung tissue. From the association constant of 18.9x10( 5) l mol(-1) min(-1) and the dissociation constant of 25.0x10(-4) min( -1) resulted the equilibrium dissociation constant K-D of 1.32 nmol/l and a relative receptor affinity of 855 with dexamethasone as referenc e (100). The half-life of the budesonide-receptor complex was 4.6 h. R esults agree with data derived from competition tests we performed ear lier. (C) 1998 Elsevier Science B.V.