Pharmacokinetics of triethylamine and triethylamine-N-oxide in man

The pharmacokinetics of the industrially important compound triethylamine (TEA) and its metabolite triethylamine-N-oxide (TEAO) were studied in four volunteers after oral and intravenous administration. TEA was efficiently absorbed from the gastrointestinal (GI) tract, rapidly distributed, and in part metabolized into TEAO. There was no significant first pass metabolism. TEAO was also well absorbed from the GI tract. Within the GI tract, TEAO was reduced into TEA (19%) and dealkylated into diethylamine (DEA; 10%). The apparent volumes of distribution during the elimination phase were 192 liters for TEA and 103 liters for TEAO. Gastric intubation showed that there was a close association between levels of TEA in plasma and gastric juice, the latter levels being 30 times higher. The TEA and TEAO in plasma had half-lives of about 3 and 4 hr, respectively. Exhalation of TEA was minimal. More than 90% of the dose was recovered in the urine as TEA and TEAO. The urinary clearances of TEA and TEAO indicated that in addition to glomerular filtration, tubular secretion takes place. For TEAO at high levels, the secretion appears to be saturable. The present data, in combination with those of earlier studies, indicate that the sum of TEA and TEAO in urine may be used for biological monitoring of exposure to TEA.