JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The National Institute of Environmental Health Sciences (NIEHS) and Brogan & Partners are collaborating with JSTOR to digitize, preserve and extend access to Environmental Health Perspectives.A comparison was made of the absorption and elimination rates of 2-propoxyethyl acetate (PEA) and 2-ethoxyethyl acetate (EEA) following inhalation, dermal application or IV administration. Male beagle dogs were exposed to 50 ppm PEA or EEA for 5 hr, and breath samples were collected during the exposure and a 3-hr recovery period. Both compounds were rapidly absorbed through the lungs. After 10 min of exposure, the concentrations of the parent compounds in the expired breath were 5 to 10 ppm (80-90% absorption) and reached plateau values at about 3 hr of 13 ppm for PEA (74% absorption) and 16 ppm for EEA (68% absorption). Post-exposure breath samples declined exponentially to 0.5 ppm and 2 ppm after 3 hr for PEA and EEA, respectively. Expired concentrations of PEA were slightly, but significantly (p < 0.025), lower than those of EEA at corresponding times during the exposure. After IV dosing with 1 mg/kg [ethyl-l,2-14C]PEA, the urine contained 61% and 88% of the dose in 4 and 24 hr, respectively. [UC]EEA was eliminated more slowly, with 20% and 61% of the dose appearing in the urine in 4 and 24 hr, respectively. Blood elimination half-lives were 1.6 hr for [UC]PEA and 7.9 hr for [14C1EEA. Only trace amounts of 14C02 (< 1%) or volatile materials (< 0.1%) were detected in the expired air with either compound. For studies of percutaneous absorption, [14C1PEA or [14C]EEA was added to undiluted compound and applied in a glass cell to a shaved area on a dog's thorax for 30 or 60 min. Blood and expired air were collected for 8 hr and urine for 24 hr. The pattern of urinary elimination for each compound was similar to that seen after IV dosing, with [14C]PEA being excreted more rapidly than [14C]EEA. Although the excretion rates for the two compounds were markedly different, the absorption rates were similar. Estimated over a 60-min period, the percutaneous absorption rates were 116 and 110 nmole/cm2/min for PEA and EEA, respectively. These values are similar to those for other lipid-soluble compounds. Taken together, these data may be extrapolated to allow the estimation of PEA and EEA uptake in man.
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