THE EXCRET ION IN BREATH OF SOME AL IPHAT IC HALOGENATED HYDROCARBONS FOLLOWlNG ADMINISTRAT ION BY INHALAT ION

Abstract--Experiments ate described in which a range of halogenated hydrocarbons, labelled with radioactive chlorine-38, were administered to volunteer subjects in a single breath. The excretion of absorbed mate ¡ in breath was followed for an hour after administration and considerable differences in the retention of the different compounds were observed. The partition coefficients (KD) between blood and air for the same compounds were measured in vitro and a correlation between retention and KD was demonstrated. The compounds excreted most rapidly in breath were 1,1,2-trichloro- 1,2,2-trifluoroethane and 1,1,1-trichloro-ethane, while 1,1,2-trichloroethane d 1,1,2,2-tetrachloroethane had the lowest rate of elimination. The excretion pattem for methyl chloride was anomalous, but could be accounted for if it reacts in the blood-stream in the same way as, but more slowly than, methyl iodide. The significance of the partition coefficient in relation to the anaesthetic action and to the relative toxicity of chlorinated hydrocarbons i discussed