[Studies on absorption, distribution and excretion of 14C labelled sodium 7 beta-[(2R, 3S)-2-(4-ethyl-2,3-dioxo-1-piperazinecarboxamido)-3-hydroxybutanamido]-7-methoxy-3-[(1-methyl-1H-tetrazol-5-YL)thiomethyl]-3-cephem-4-carboxylate (14C-T-1982) in mice and rats].

Absorption, distribution and excretion of sodium 7 beta-[(2R,3S)-2-(4-ethyl-2,3-dioxo-1-piperazinecarboxamido)-3-hydroxybutanamido ]-7 alpha-methoxy-3-[(1-methyl-1 H-tetrazol-5-yl) thiomethyl]-3-cephem-4-carboxylate (T-1982) were studied in rats and mice using of 14C-T-1982. 1. The binding rate of 14C-T-1982 to serum protein was about 16% in mouse, 27% in rat and 50% in human. 2. After intravenous administration to mice and rats, blood levels of radioactivity diminished rapidly. While, after subcutaneous administration to mice and intramuscular administration to rats, blood levels reached rapidly to high concentration and, declined gradually in comparison with intravenous studies. 3. Radioactivity after parenteral administration to rats and mice was distributed high into kidney, following by liver, stomach, heart, lung and ovarium, but low into brain. In new born rats, tissue levels diminished slower than that of adult rats. 4. With regard to oral administration to mice, almost all radioactivity was found in feces. This result suggested that T-1982 was hardly absorbed from gastrointestinal tracts. Urinary excretion rate after intravenous administration was about 60% in mice and 19% in rats, and the other radioactivity was found in feces. 5. In rats, radioactivity was excreted in bile at biliary excretion rate of about 80% after intravenous administration. 6. After intravenous administration to nursed rats, radioactivity was hardly detected in gastrointestinal tracts of sucklings. And from the study on distribution of radioactivity in pregnant mice, it was suggested that T-1982 scarcely passed placenta. 7. Excretion pattern after multiple administration to rats was similar to that of single administration. This result suggested that T-1982 did not produce accumulation of it in body.