Disposition of ipriflavone (TC-80) in rats and dogs.

Oral 14C-ipriflavone was absorbed by rats to give a maximum plasma 14C level at 1.5 h and a half-life of 5.8 h. In dogs, after po dosing, the plasma 14C peaked at 0.5 h, followed by gradual decline. The plasma of both animals contained mostly metabolites, with small amounts of unchanged ipriflavone. In rats, 14C was distributed widely in tissues, with relatively high concns. in the liver, kidney and gut. Distribution in rat thigh bone of unmetabolized ipriflavone was also demonstrated. 14C-Ipriflavone was eliminated mostly as metabolites within 48 and 72 h, respectively, in rats and dogs. Rats excreted more 14C in urine than in feces, whereas the reverse was noted in dogs. Biliary excretion and reabsorption of 14C were also obvious in both animals.