Acute toxicity, percutaneous absorption and effects on hepatic mixed function oxidase activities of 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) and its chlorinated derivatives.

Acute toxicity of 2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP300) (I) and its three chlorinated derivatives, 2',3,4,4'-tetrachloro-2-hydroxydiphenyl ether (II), 2',4,4',5-tetrachloro-2-hydroxydiphenyl ether (III) and 2',3,4,4',5-pentachloro-2-hydroxydiphenyl ether (IV), in mice were examined by intraperitoneal injection. The LD50 values of Irgasan DP300, II, III and IV were 1,090, 710, 650 and 430 mg/kg, respectively. The percutaneous absorptions of these tritiated compounds were also examined by the application on the backs of mice. The radioactivities in most tissues reached to the maximal levels at 12 h or 18 h after dosing, which corresponded to 11-76% of the maximal levels given by the oral administration (Kanetoshi et al. 1988a). These results show the high percutaneous absorbability of Irgasan DP300 and its chlorinated derivatives. The intraperitoneal administrations of III and IV to rats induced hepatic microsomal aminopyrine N-demethylase and aniline 4-hydroxylase activities similarly to phenobarbital. These chlorinated derivatives also increased cytochrome P-450 content, and the activities of aminopyrine N-demethylase and N-methylaniline N-demethylase in hepatic microsomes from mice. The extents of the increases were similar to those by phenobarbital and 3-methylcholanthrene.