The metabolism and disposition of 14C-fenofibrate in human volunteers.

The metabolic fate of a single dose of 14C-fenofibrate has been studied in a panel of eight healthy volunteers (four males and four females). In 7 days, a total of 84% of the administered dose was recovered, with 59% in the urine and 25% in the feces. The majority of the urinary 14C was excreted within 24 hr, whereas the bulk of the fecal 14C was recovered over the first 3 days after dosing. The major urinary metabolite was the ester glucuronide of fenofibric acid, accompanied by much smaller amounts of fenofibric acid and the benzhydrol and its glucuronide. The principal compound in feces was unchanged fenofibrate, together with smaller quantities of fenofibric acid and polar unknown metabolite(s). Experiments on the stability of fenofibryl glucuronide showed it to be less reactive than most ester glucuronides.