title: Metabolic fate of 1-hexylcarbamoyl-5-fluorouracil in rats.
abstract: 1. The metabolic fate of a new antitumour agent, 1-hexylcarbamoyl-5-fluoro [6-14C]uracil (14C-HCFU) in rats after oral administration was compared with that of 5-fluoro[6-14C]uracil (14C-FU). 2. Tissue radioactivity reached a max. 1 to 3 h after administration of 14C-HCFU and 0.5 h after 14C-FU. 3. Both drugs were excreted rapidly, mostly in urine. Expired 14CO2 from 14C-HCFU was significantly less than that from 14C-FU. 4. Unchanged FU was not detected in plasma 3 h after administration of 14C-FU, whereas FU was detected in plasma 5 h after 14C-HCFU. The pyrimidine ring of 14C-HCFU might be degradated more slowly than that of 14C-FU. 5. 1-(5-Carboxypentylcarbamoyl)-5-fluorouracil and 1-(3-carboxypropylcarbamoyl)-5-fluorouracil were identified as the major urinary metabolites of 14C-HCFU.
mesh_terms: D000818:Animals; D001711:Biotransformation; D001944:Breath Tests; D005243:Feces / Q000032:analysis; D005472:Fluorouracil / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000652:urine; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D014018:Tissue Distribution
chemical_list: C017367:carmofur; D005472:Fluorouracil