JOHANSON G, KRONBORG H, NAsLUND PH , BYFALT NORDQVIST M. Toxicokin etics of inhaled 2-butoxyethanol (ethylene glycol monobutyl ether) in man . Scand J Work Environ Health 12 (1986) 594-602. Seven male volunteers were exposed to 2-butoxyethanol at the Swedish occupational exposure limit (20 ppm or 0.85 mrnol /rnt) during light physical exercise (50 W) on a bicycle ergometer. The exposure took place in an exposure chamber and lasted 2 h. Expired air was collected at regular time intervals for estimation of the respiratory uptake of the solvent. Arterialized capillary blood and urine were sampled during and after the exposure period and analyzed for 2-butoxyethanol and its metabolite butoxyacetic acid. A new sensitive method for analyzing 2-butoxyethanol in biological specimens is described . 2-Butoxyethanol was derivatized with pentafluorobenzoyl chloride and analyzed by gas chromatography with electron capture detection. The respiratory uptake of 2-butoxyethanol averaged 10.1 /lmollmin or 57 010 of the inspired amount. The concentration in blood reached a plateau level of 7.4 /lmolli. The apparent values of elimination half-t ime, mean residence time, total blood clearance, and steady-state volume of distribution were 40 min , 42 min , 1.2 l1min and 541, respecti vely. The amount of 2-butoxyethanol excreted in urine was less than 0.03 010 of the total uptake, while that of butoxyacetic acid ranged from 17 to 55 010.

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To study the influence of cigarette smoking on the toxicokinetics of toluene, 10 habitual smokers who intended to stop smoking were exposed to toluene vapor (3.2 mmol/m3, 4 h) at three different exposure occasions: (I) while the smoking habit was still ongoing, and (II and III) 1 and 3-4 wk, respectively, after the day at which the smoking habit was discontinued. Solvent concentrations in the exhaled air and in the blood as well as hippuric acid concentrations in the urine were measured during the exposure period and for 3 h after the exposure period. The apparent clearance of toluene decreased significantly (p less than 0.05) 3-4 wk after the smoking habit was discontinued. This decrease was not a consequence of the increased body weight noticed in the subjects. No statistically significant differences between the three exposure occasions in the elimination rate of hippuric acid could be demonstrated. Thus, cigarette smoking seems to enhance the elimination rate of toluene from the body, since the apparent clearance was decreased after smoking was stopped.