Ethoxyacetic acid: a metabolite of ethylene glycol monoethyl ether acetate in man

Urinary excretion of ethoxyacetic acid during and after exposure to ethylene glycol monoethyl ether acetate (EGEE-Ac) was followed up in ten healthy male volunteers. During exposure to EGEE-Ac, ethoxyacetic acid levels appeared with a half life of 2.3 +/- 0.1 h. Ethoxyacetic acid excretion continued to increase after exposure was discontinued reaching maximal levels three to four hours later. The decline afterwards could generally be described assuming a half life of 23.6 +/- 1.8 h. A second maximum excretion of ethoxyacetic acid, however, was noticed about three hours after the first. Redistribution of EGEE-Ac or ethoxyacetic acid, or both, from a peripheral compartment to the central compartment could explain this observation. Ethoxyacetic acid excretion increased with an increase in the uptake of EGEE-Ac due to higher exposure concentrations or pulmonary ventilation rate during physical exercise. On average 22.2 +/- 0.9% of the absorbed EGEE-Ac was recovered within 42 hours. Recovery did not change with a higher intake of EGEE-Ac. At any time after the exposure, quantitative relations between ethoxyacetic acid excretion rate and absorbed dose of EGEE-Ac were found. Monitoring ethoxyacetic acid excretion may therefore be used as a measure of a single exposure to EGEE-Ac.