Abstract

1,3-Diphenyl-1-triazene (DPT) is used in the synthesis of polymers and dyes, and has been found as an impurity in the color additives D&C Red 33 and FD&C Yellow 5. [¹⁴C]DPT, randomly labeled in the phenyl rings, was used to investigate its disposition in rodents. Dermal doses to rats and mice (2 and 20 mg/cm²) were poorly absorbed (≤7%) in 72 h of exposure. Oral doses of DPT (20 mg/kg) to male rats and mice were well absorbed and excreted mainly in the urine, with exhalation of volatile organics accounting for about 1% of the dose. The sole volatile component present in breath was benzene, and all of the metabolites present in urine were composed of those known for the differential metabolism of benzene and for aniline in the two species. Benzene and aniline were detected in the blood of rats administered oral doses of DPT, and relatively high circulating levels of their metabolites were measured as early as 15 min postdosing. Metabolites of these two carcinogens were also formed in human liver slices, indicating a carcinogenic potential for DPT in humans.