2,4-Xylidine is absorbed through the GI tract, the skin and the respiratory tract. It is metabolized and excreted in the urine. In the urine of rats, 2,4-xylidine appears mainly unchanged or as 4-amino-3-methylbenzoic acid or N-acetyl-4-amino-3-methylbenzoic acid and their sulfate or glucuronide conjugates. These compounds are formed after oxidation at the p- methyl group. In addition, 6-hydroxy-2,4-xylidine has been identified as a major metabolite in the urine or dogs. Traces of N-methyl-2,4-dimethyl-aniline are also detectable in the urine of both species. The quantity of metabolites in the urine does not incr after repeated admin of 2,4-xylidine.
The xylidine 2,4-dimethylaniline produces hepatic cholangiofibrosis, bile duct proliferation, and foci of cellular hyperplasia and degeneration in the rat. The same cmpd is relatively innocuous in the dog. ... The major urinary metabolite of 2,4-dimethylaniline in the rat was N-acetyl-4-amino-3-methylbenzoic acid while in the dog it was 6-hydroxy-2,4-dimethylaniline. The dog also produced a smaller amt of unacetylated 4-amino-3-methylbenzoic acid and its glycine conjugate. ... In rats, repeated admin of either xylidine /2,4-dimethylaniline or 2,6-dimethylaniline/ for 10 days failed to incr the appearance of metabolites, but 3-methylcholanthrene did incr the urinary concn of N-acetyl-4-amino-3-methylbenzoic acid in 2,4-dimethylaniline dose rats.
Classification of carcinogenicity: 1) evidence in humans: no adequate data; 2) evidence in animals: inadequate. Overall summary evaluation of carcinogenic risk humans is Group 3: The agent is not classifiable as to its carcinogenicity to humans. /From table/
IARC Monographs:Volume 16: (1978) Some Aromatic Amines and Related Nitro Compounds – Hair Dyes, Colouring Agents and Miscellaneous Industrial Chemicals
来源:International Agency for Research on Cancer (IARC)