1Dermal, Oral, and Inhalation Pharmacokinetics of Methyl tertiary Butyl Ether (MTBE) in Human Volunteers

Methyl tertiary butyl ether (MTBE), a gasoline additive, used to increase octane and reduce carbon monoxide emissions and ozone precursors has contaminated drinking water leading to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhalation kinetics, 14 volunteers were exposed to 51.3:g/ml MTBE dermally in tap water for one hr, drank 2.8 mg MTBE in 250 ml Gatorade®, and inhaled 3.1 ppm MTBE for one hr. Blood and exhaled breath samples were obtained. Blood MTBE peaked between 15-30 min following oral exposure, at the end of inhalation exposure, and ~5 min after dermal exposure. Elimination by each route was described well by a 3-compartment model (Rsq> 0.9). The Akaike Information Criterion for the 3-compartment model was smaller than the 2-compartment model supporting it over the 2-compartment model. One metabolite, tertiary butyl alcoho