Disposition kinetics of ethylene oxide, ethylene glycol, and 2-chlorethanol in the dog

The disposition kinetics of ethylene oxide, ethylene glycol, and 2-chloroethanol were studied following their intravenous administration to beagle dogs. Plasma concentration of ethylene oxide was found to decline exponentially with a mean rate constant of 0.024 +/- 0.008 min-1 (mean +/- SD) and total body clearance of 20.0 +/- 5.2 ml/kg X min. Ethylene oxide was found to be metabolized mainly to ethylene glycol, which had a mean plasma half-life of 221.0 +/- 77.7 min and a total body clearance of 2.13 +/- 0.58 ml/kg X min. Between 7 and 24% of intravenously administered ethylene oxide was eliminated in the urine as ethylene glycol within 24 h. The elimination half-life and clearance values for 2-chlorethanol were 40.8 +/- 5.7 min and 10.3 +/- 1.7 ml/kg X min, respectively. The pharmacokinetic data gathered in the present investigation suggest that ethylene glycol rather than 2-chloroethanol is the major metabolite of ethylene oxide in the dog.