R. K. Lynn, R. K. Lynn, David W. Donielson
Nov 1, 1980
Citations
1
Influential Citations
77
Citations
Quality indicators
Journal
Toxicology and applied pharmacology
Abstract
A series of bisazobiphenyl dyes derived from benzidine, 3-3′-dimethylbenzidine or 3,3′-dimethoxybenzidine were studied in the dog and rat. The dyes, which are commercially useful in the textile and leather industries, possess potential for metabolism to the carcinogenic aromatic amines, benzidine, 3,3′-dimethylbenzidine and 3,3′-dimethoxybenzidine via metabolic reduction of the azo bonds. Dyes were administered orally and the urine analyzed for benzidine, 3,3′-dimethyl- or 3,3′-dimethoxybenzidine using a specific gas chromatographic assay. The identity of the chromatographic peaks was confirmed by gas chromatography-mass spectrometry. Dogs treated acutely (100 mg/kg) with benzidine derived dyes excreted substantial quantities of benzidine (166–1675 μg) in urine (0–48 hr). No benzidine was detected in urine prior to treatment. Benzidine present in dog urine following dye administration exceeded by at least ninefold the benzidine present as impurity in the administered dyes and was comparable to that excreted in urine when pure benzidine was fed (100 mg/kg). Rats chronically dosed (100 mg/kg/day) with benzidine-based dyes excreted N-acetylbenzidine (3–54 μg/day) and traces of benzidine in urine. Bisazobiphenyl dyes derived from 3,3′-dimethylbenzidine and 3,3′-dimethoxybenzidine were metabolized to 3,3′-dimethyl- and 3,3′-dimethoxybenzidine, respectively, in both the dog and rat. The N-acetyl derivatives of 3,3′-dimethyl- and 3,3′-dimethoxybenzidine were identified in urine from rats treated with dyes derived from 3,3′-dimethyl- and 3,3′-dimethoxybenzidine, respectively. Results from this study indicate that the metabolic conversion of bisazobiphenyl dyes, derived from benzidine and 3,3′-dimethyl- and 3,3′-dimethoxybenzidine, to carcinogenic aromatic amines is a general phenomenon and therefore with few exceptions should be anticipated for each member of this class of chemicals.