Teratological assessment of five oxidative hair dyes in the rat

The oxidative dyes, 4,4′-diaminodiphenylene sulfate, N′-(2-hydroxyethyl)-4-nitro- O-phenylenediamine, N,N-dimethyl- p-phenylenediamine, 2,3-dihydroxynaphthalene, and resorcinol, were evaluated for teratogenic potential. Dyes were administered by gavage to pregnant Sprague-Dawley rats on gestation Days 6 through 15 at doses ranging from 12.5 to 500 mg/kg. No overt signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during the treatment period at the high dose for 4,4′-diaminodiphenylene sulfate, N′-(2-hydroxyethyl)-4-nitro- O-phenylenediamine, and 2,3-dihydroxynaphthalene. The high dose for N,N-dimethyl- p-phenylenediamine and resorcinol, which exceeded a 100-fold exaggeration of human exposure, did not produce a significant reduction in maternal weight gain. An evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye-treated and vehicle control groups. Administration of 100,000 units of vitamin A, the positive control, on Day 9 of gestation resulted in a significant increase in abnormal fetuses.