Dược Động Học :
▧ Absorption :
Nepafenac rapidly cross the cornea (6 times faster than diclofenac in vitro).
▧ Protein binding :
Amfenac has high affinity toward serum albumin proteins. In vitro, the percent bound to human albumin and human serum was 95.4% and 99.1% respectively.
▧ Metabolism :
Nepafenac (prodrug) is deaminated to amfenac (active compound) in the ciliary body epithelium, retina, and choroid by intraocular hydrolases. Subsequently, amfenac undergoes extensive metabolism to more polar metabolites involving hydroxylation of the aromatic ring leading to glucuronide conjugate formation.
▧ Route of Elimination :
After oral administration of 14C-nepafenac to healthy volunteers, urinary excretion was found to be the major route of radioactivity elimination, accounting for approximately 85% of the dose, while fecal excretion represented approximately 6% of the dose. Nepafenac (prodrug) and amfenac (active compound) were not quantifiable in the urine.