Absorption, distribution and excretion of [14C]carmoisine in mice after oral and intravenous administration

Male Swiss albino mice (CD-1) were given single doses of [14C]carmoisine by stomach tube (200 mg/kg, 6 μCi) or iv injection (200 mg/kg; 0.7 μCi). The plasma and tissue kinetics of the compound were studied by monitoring the decay of radioactivity in the plasma, gastro-intestinal tract, liver, kidney, lung, testes, spleen and gall bladder. The feces and urine of mice placed in individual metabolism cages were collected between 4 and 96 hr after dosing. After oral administration, peak levels of radioactivity occurred in the plasma and the liver, lungs, testes and spleen 8 hr after dosing. Radioactivity was almost completely (98%) excreted in the feces and urine within 16-32 hr after oral dosing. The plasma [14C]radioactivity decay curve after iv administration indicated a very rapid distribution of the compound into the tissues (t(1/2)=10 min) and an efficient excretion, mostly through the gastro-intestinal tract (92%), which was complete 48 hr after dosing.