[Experimental examinations and toxicokinetic analysis of the absorption and excretion of 1,1,1-trichloroethane by the lung].

Of fifteen dogs each five of them inhaled 1,1,1-trichloroethane (1,1,1-TCE) at the levels of 700, 1500 and 2,000 ppm respectively for one hour. Changes in 1,1,1-TCE concentrations in the expired air, arterial blood and venous blood of dogs were measured from the beginning of exposure until one hour after the end of exposure. The results obtained were as follows. 1. Cumulative uptakes of 1,1,1-TCE in one hour exposure were 27.3 mg/kg at 700 ppm, 44.7 mg/kg at 1,500 ppm and 71.2 mg/kg at 2,000 ppm. 2. Excretion ratios of 1,1,1-TCE in one hour after the exposure were 66-71% at all the three levels of exposure. 3. During the exposure, highly significant negative correlation was seen between arterial/venous blood concentration ratio and expired/inspired air concentration ratio. In the post-exposure period, highly significant positive correlations were seen between expired air concentration and venous or arterial blood concentration. 4. The mean ratio of the total absorption value to the total inspired value was 14% at all the three levels of exposure. 5. From these results, the authors examined the multiple regression equations with two independent variables x and z which are shown as follows. a) During the exposure period, Y1: Cumulative absorption solvent value by the dog (mg/kg) X1: Time of exposure (min) Z1: Level of the solvent value in the ambient air (microgram/ml) log Y1 = -0.526 + 0.622 log X1 + 0.905 log Z1 b) Post exposure period, Y2: Cumulative excreted solvent value by the dog (mg/kg) X2: Time after the end of exposure (min) Z2: Cumulative absorbed solvent value by the dog at the end of exposure (mg/kg) log Y2 = -2.300 + 0.609 log X2 + 0.858 log Z2 We assumed that both equations are very fit and significant.