title: The absorption and excretion of the peripheral vasodilator 14C-mecinarone, (14C-6809 MD) in rat, dog and man.
abstract: Oral doses of the peripheral vasodilator mecinarone (6809 MD), administered as the 14C-compound, were well absorbed from the gastrointestinal tract of rats, dogs and humans. Much of the dose was excreted in 24 by rats and dogs, but more slowly by humans. In 5 days, rats, dogs and humans excreted in the urine and faeces respectively means of 3.3 and 95.9%, 13.2 and 80.3%, and 22.0 and 60.8%. The proportions of radioactivity excreted in urine and faeces after intravenous doses were similar to those after oral doses, means of 3.1 and 85.0% respectively by rats and 16.8 and 78.3% by dogs. Radioactivity present in the faeces was probably mainly excreted in bile; rats (n = 2) excreted a mean of 52.3, 19.8 and 3.9% in bile, faeces and urine after oral doses. Plasma concentrations of radioactivity after oral doses reached a maximum at 1 h in rats (mean 126 ng equiv/ml), at 1 to 2 h in dogs (mean 784 ng equiv/ml) and at 1.5 to 2 h in humans (mean 547 ng equiv/ml. Only a small proportion of this radioactivity (10-30%) represented unchanged drug. When "normalised" for dose/bodyweight differences, those levels were in the ratio 1 : 7 : 32 (rat less than dog less than man). Areas under plasma radioactivity concentration-time curves after oral doses to rats and dogs were about 25% and 53% respectively of those after corresponding intravenous doses. Only about 20% of the radioactivity in the plasma of dogs at 2 min after an intravenous dose represented unchanged drug. These data suggest that 6890 MD was probably rapidly biotransformed in rat, dog and man.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001572:Benzofurans / Q000097:blood / Q000378:metabolism*; D001646:Bile / Q000378:metabolism; D002250:Carbon Radioisotopes; D002599:Chalcone / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism; D004285:Dogs; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007408:Intestinal Absorption; D007700:Kinetics; D008297:Male; D051381:Rats; D013045:Species Specificity; D014665:Vasodilator Agents / Q000097:blood / Q000378:metabolism*
chemical_list: D001572:Benzofurans; D002250:Carbon Radioisotopes; D014665:Vasodilator Agents; D002599:Chalcone; C011021:mecinarone