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Metabolism of azo dyes to potentially carcinogenic aromatic amines.

Nony CR
Rockville, MD: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, 1979 Mar; :1-83
The in vivo transformation of Direct-Black-38 (1937377) (DB 38) and Pigment-Yellow-12 (6358856) (PY 12) to potentially carcinogenic metabolites was studied. Hamsters were given a single oral dose of 100 milligrams per kilogram of DB 38 or PY 12. Urine samples were collected for up to 7 days after treatment, and analyzed by electron capture gas chromatography and high pressure liquid chromatography. Urine samples from the animals treated with DB 38 were tested for mutagenicity in the Ames Salmonella microsome assay. Urine from the DB 38 treated hamsters contained benzidine (92875), monoacetylbenzidine (3366618), diacetylbenzidine (613354), 4- aminobiphenyl (92671), and alkaline hydrolyzable conjugates of benzidine and 4-aminobiphenyl. The greatest amounts of most of the metabolites were excreted within 8 hours of dosing; the greatest amounts of diacetylbenzidine and alkaline hydrolyzable conjugates of benzidine were excreted 8 to 16 hours after dosing. By 32 hours, most of the metabolite excretion returned to background levels, but monoacetylbenzide and alkaline hydrolyzable conjugates of benzidine were still detected 7 days after treatment. Mutagenic potential was correlated with the amount of monoacetylbenzidine present. None of the proposed metabolites of PY 12 were found in the urine of hamsters treated with that dye. The authors conclude that occupational exposure to DB 38 increases the risk of bladder cancer. Industrial discharge of the dye could result in environmental contamination. The use of this dye should be monitored.
NIOSH-Contract; Contract-224-78-0004; Invivo-study; Laboratory-animals; Carcinogenesis; Subcellular-structure; Oxidative-metabolism; Sampling-methods; Chemical-exposure; Mutagenesis; Coloring-materials; Analytical-methods; Body-retention; Metabolic-effects
1937-37-7; 6358-85-6; 92-87-5; 3366-61-8; 613-35-4; 92-67-1
Publication Date
Document Type
Interagency Agreement
Funding Type
Interagency Agreement
Fiscal Year
NTIS Accession No.
NTIS Price
NIOSH Division
Source Name
National Institute for Occupational Safety and Health
Performing Organization
National Center for Toxicological Research Jefferson, Arkansas 72079
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division