Dược Động Học :
▧ Volume of Distribution :
* 3 to 5 L/kg
▧ Protein binding :
99% (mainly VLDL, LDL, and HDL)
▧ Metabolism :
Metabolism of fulvestrant appears to involve combinations of a number of possible biotransformation pathways analogous to those of endogenous steroids, including oxidation, aromatic hydroxylation, conjugation with glucuronic acid and/or sulphate at the 2, 3 and 17 positions of the steroid nucleus, and oxidation of the side chain sulphoxide. Identified metabolites are either less active or exhibit similar activity to fulvestrant in antiestrogen models. Studies using human liver preparations and recombinant human enzymes indicate that cytochrome P-450 3A4 (CYP 3A4) is the only P-450 isoenzyme involved in the oxidation of fulvestrant; however, the relative contribution of P-450 and non-P-450 routes in vivo is unknown.
▧ Route of Elimination :
Fulvestrant was rapidly cleared by the hepatobiliary route with excretion primarily via the feces (approximately 90%).
Renal elimination was negligible (less than 1%).
▧ Half Life :
40 days