Distribution, excretion, and metabolism of nitro-p-phenylenediamine in rats.

The distribution, excretion, and metabolism of nitro-p-phenylenediamine, a constituent of hair dye, was studied after administration of [14C]nitro-p-phenylene-diamine (2.6 mg/30 microCi/kg) to male rats. After intraperitoneal administration, 37.4% of the radioactivity administered was excreted in the urine and 54.3% in the feces within 24 h. After intravenous administration, 42.2% of the radioactivity was excreted in the bile within 24 h. The highest concentration of radioactivity in tissues was found at 1 h, except in the small and large intestines, followed by a rapid decrease in concentration. Only small amounts of radioactivity were found in the tissues 48 h after administration. Some of the radioactive materials in the urine were separated by thin-layer chromatography and identified as N1,N4-diacetyl-2-amino-p-phenylenediamine, N4-acetyl-2-nitro-p-phenylenediamine, and unchanged nitro-p-phenylenediamine.