Disposition of KW-4679 (3) : Absorption and Excretion of 14C-KW-4679 after Oral Administration to Dogs

The absorption and excretion of 14C-KW-4679 after oral administration were studied in dogs. 1) The plasma level of radioactivity reached the peak (723.2 ng eq./ml) at 1.13 hr after administration, and then radioactivity was eliminated almost monophasically with a half-life of 4.53 hr. 2) The transfer of 14C-KW-4679 to blood cells was nearly constant in the period from 2 to 12 hr after administration with an extent of 31.7 to 35.5%. 3) The serum protein binding of 14C-KW-4679 in vivo was nearly constant (53.1 to 56.8%) from 0.5 to 12 hr after administration. 4) By 168 hr after administration, 73.4% and 22.9% of the dose were excreted in urine and feces, respectively, with a total excretion of 96.3%. The excretion had been almost completed within 48 hr after administration.