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.

A quantitative in vitro assay for the evaluation of phototoxic potential of topically applied materials.

A quantitative in vitro method for phototoxic evaluation of chemicals has been developed and validated. The assay uses Saccharomyces cerevisiae, seeded in an agar overlay on top of a plate count agar base. 8-Methoxy psoralen is used as a reference standard against which materials are measured. Activity is quantified by cytotoxicity measured as zones of inhibition. Several known phototoxins (heliotropine, lyral, phantolid, and bergamot oil) and photoallergens (6-methyl coumarin and musk ambrette) are used to validate the assay. An excellent correlation is observed between in vivo studies employing Hartley albino guinea pigs and the in vitro assay for several fragrance raw materials and other chemicals. The in vitro assay exhibits a greater sensitivity from 2-500 fold. For three fragrance oils, the in vitro assay detects low levels of photobiological activity while the in vivo assay is negative. Although the in vitro assay does not discriminate between phototoxins and photoallergens, it can be used for screening of raw materials so that reduction in animal usage can be achieved while maintaining the protection of the consumer.

Evaluation of the teratogenic potential of the oxidative dye N-phenyl-para-phenylenediamine.

The oxidative dye N-phenyl-para-phenylenediamine was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 50, 100, and 200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with fetuses having external, visceral, and skeletal anomalies.

Teratological assessment of the oxidative dye 4-methyl-N-ethylamino phenol sulfate.

The oxidative dye 4-methyl-N-ethylamino phenol sulfate was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 300, 600, and 1200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 1200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with abnormal fetuses.