5 Final Report on the Safety Assessment of 2-Nitro- p -Phenylenediamine and 4-Nitro- o -Phenylenediamine

Final Report on the Safety Assessment of 2-Chloro-p-Phenylenediamine and 2-Chloro-p-Phenylenediamine Sulfate

2-Chloro-p-Phenylenediamine and 2-Chloro-p-Phenylenediamine Sulfate are colorants used in hair dyes at concentrations less than 1.0%. In an oral subchronic toxicity test using rats and mice, all male rats and one female rat died in the 1 % concentration of 2-Chloro-p-Phenylenediamine dose group; at 0.3%, no rats or mice died but the mean body weight gain was depressed. In the mice, one of the males and none of the females died in the 1 % dose group. In a test for ocular irritation, 2.5% 2-Chloro-p-Phenylenediamine produced, at most, only mild conjunctival inflammation. 2-Chloro-p-Phenylenediamine was not a sensitizer when assayed on abraded and intact skin. The cited chronic studies do not provide sufficient evidence to conclude that the compound was carcinogenic in either mice or rats. Epidemiological studies, both prospective and retrospective, support this conclusion. On the basis of the data presented in the report, it is concluded that 2-Chloro-p-Phenylenediamine and 2-Chloro-p-Phenylenediamine Sulfate are safe as a “coal tar” hair dye ingredient at the current concentrations of use.

Final Report on the Safety Assessment of Toluene-2,5-Diamine, Toluene-2,5-Diamine Sulfate, and Toluene-3,4-Diamine

The diaminotoluenes 2,5-TD, 2,5-TDS, and 3,4-TD are used as colorants in permanent hair dyes and tints. 2,5-TD is used at concentrations up to 1 % and 2,5-TDS is used up to 5%. The major routes of excretion after cutaneous absorption by rats were through the urine and feces. The oral LD50 of 2,5-TDS in rats was 98 mg/kg. There was no evidence of percutaneous toxicity to rabbits when 6% 2,5-TDS was applied to intact or abraded skin. In a two-year study, no toxicity was reported in rats receiving biweekly cutaneous applications of formulations containing 3% or 4% 2,5-TD. Mice were also unaffected by 3% 2,5-TDS in an 18-month study, or by 3% 2,5-TD in a two-year study. Rabbits had a slight dermal irritation response after exposure to 2.5% 2,5-TDS, but no irritation occurred in guinea pigs after exposure to 10% solutions of 2,5-TDS or 3,4-TD. 2,5-TD (2.5%) caused mild, transitory conjunctival inflammation in rabbits. The results of sensitization tests of 2,5-TD, 2,5-TDS, and 3,4-TD indicated that each of these diaminotoluenes were sensitizers to laboratory animals and humans. 2,5-TDS was toxic to pregnant rats and their embryos at oral doses of 80 mg/kg/day. Doses between 10 and 50 mg/kg/day did not cause congenital or maternal abnormalities. o-Toluenediamine, a mixture of 2,3-TD and 3,4-TD (40:60), was not teratogenic when administered orally to rats or rabbits. Cutaneous exposure to hair dye formulations containing 3% 2,5-TDS caused a statistically significant increase in fetal skeletal anomalies in rats. Rats treated with 6% 2,5-TDS did not have this adverse response. In a two-generation reproduction study, mice receiving dermal applications of hair-dye formulations containing either 3% or 6% 2,5-TDS had no signs of pharmacotoxicity, teratogenicity, or reproductive abnormalities. The results cited from various mutagenicity assays of 2,5-TD, 2,5-TDS, and 3,4-TD varied in accordance with the assay system and protocols used. 2,5-TD and 2,5-TDS were noncarci-nogenic to rats and mice in both oral and dermal exposure studies. On the basis of the animal and clinical data presented in this report, and the required labeling, it is concluded that Toluene-2,5-Diamine Sulfate and Toluene-3,4-Diamine are safe as cosmetic ingredients in the present practices of use.

2 Final Report on the Safety Assessment of p-Aminophenol, m-Aminophenol, and o-Aminophenol

p-Aminophenol (PAP), m-Aminophenol (MAP), and o-Aminophenol (OAP) are used in permanent (oxidative) hair dyes at concentrations from 0.1 to 5%. In vivo and in vitro skin absorption studies indicated that 11% of the dermally applied 14C-PAP was detected in the excreta, viscera, and skin of the test animals. The oral LD50s of PAP, MAP, and OAP in rats ranged from 600 to 1300 mg/kg. Topical application of PAP at concentrations up to 8.00 g/kg to the skin of New Zealand white (NZW) rabbits produced no skin irritation and no mortality. PAP, MAP, and OAP were irritating to eyes of NZW rabbits at a concentration of 2.5%. MAP at 3% was nonsensitizing in guinea pigs; PAP at 2% sensitized 9 of 10 guinea pigs. Neither PAP nor MAP produced photosensitization in guinea pigs. No treatment-related toxicity was found in three separate four-generation chronic dermal toxicity and reproduction studies of hair dye formulations containing the three Aminophenols. Additional studies on the pure ingredients were also nonteratogenic; embryotoxicity was reported. A range of results was obtained from studies assessing the mutagenic activity of the Aminophenols. PAP tested positive in six of eight mutagenicity tests. MAP and OAP gave positive results in two of eight and five of seven mutagenicity tests, respectively. Oxidative hair dye formulations containing PAP, MAP, and OAP did not produce gross or microscopic alterations or have carcinogenic effects after chronic topical application to mice. Feeding of OAP-HCl and PAP to rats at a dose of 8 mmol/kg produced neither hepatic cirrhosis nor neoplastic lesions. A 3% solution of MAP in an aqueous vehicle was neither a significant irritant nor sensitizer in two clinical studies. A variety of epidemiological studies have not indicated that occupational exposure to, and personal use of, hair dyes containing the Aminophenols presented a carcinogenic risk. A discussion of the significance of the mutagenic data in the safety assessment and the potential for human effects is presented. On the basis of the available animal and clinical data presented in this report it is concluded that p-, m-, and o-Aminophenols are safe as cosmetic ingredients in the present practices of use and concentrations.

Final Report on the Safety Assessment of Phenyl Methyl Pyrazolone

Phenyl Methyl Pyrazolone (PMP) is a heterocyclic amine that is used in hair colorants. The phenylhydrazine content in PMP is below the limit of detection. Phenyl Methyl Pyrazolone was slightly toxic to rats, with an oral LD50 of 3.5 g/kg. Feeding rats and mice with PMP-treated feed for 7 weeks was uneventful. A compound containing 500 mg/kg of PMP was, at most, a mild ocular irritant. Phenyl Methyl Pyrazolone was slightly irritating to rabbit skin when tested under occlusive patches. It did not produce a sensitization reaction in guinea pigs. Phenyl Methyl Pyrazolone was nonmutagenic in two assays and noncarcinogenic in oral feeding studies. On the basis of the available data presented in this report, it is concluded that Phenyl Methyl Pyrazolone is safe for use as a cosmetic ingredient in the present practices of use and concentration.

Final Report on the Safety Assessment of 4-Methoxy-m-Phenylenediamine, 4-Methoxy-m-Phenylenediamine Sulfate, and 4-Methoxy-m-Phenylenediamine-HCl

The hair dye ingredient 4-Methoxy-m-Phenylenediamine Sulfate (4-MMPDS) prior to 1978 was used extensively used in the United States. Concerns raised because of studies which showed the hair dye to be an animal carcinogen prompted the voluntary reformulation and deletion of 4-MMPD in hair dyes containing this ingredient. No reports were made on the use of this ingredient until 1989 when 17 uses were reported. Assays on volunteers indicate that less than 0.2% of the dye penetrates the scalp and that about 3.9% is absorbed through the skin of the forearm. The dye is metabolized and excreted in the urine; a major metabolic product was 4-acetylamino-2-aminoanisole. The LD50 range in rats of aqueous solutions of 4-MMPD was 400–500 mg/kg. No gross tissue abnormalities were reported in subchronic feeding or dermal studies. 4-MMPD was not an ocular irritant when tested at 2.5%, but was a mild skin irritant when tested at the same concentration. The dermal application of hair dye formulations containing up to 4.0% 4-MMPD were negative for both embryotonic toxicity and teratogenic effects. The results of numerous mutagenic studies vary between the assay system used. 4-MMPD was noncarcinogenic in four dermal carcinogenic studies, but was carcinogenic to both rats and mice in feeding studies. On the basis of the information included in this report, it is concluded that 4-Methoxy-m-Phenylenediamine, 4-Methoxy-m-Phenylenediamine Sulfate, and 4-Methoxy-m-Phenylenediamine HCl are unsafe for use in cosmetic products.

Percutaneous penetration and metabolism of 2-nitro-p-phenylenediamine in human and fuzzy rat skin

2-Nitro-p-phenylenediamine (2NPPD) is a dye used in semipermanent and permanent (tinting color) hair dye formulations. National Toxicology Program toxicology and carcinogenesis testing of 2NPPD has raised concerns about its safety. Therefore, we initiated in vitro studies to measure absorption and metabolism of 2NPPD in human and fuzzy rat skin and rat jejunal tissue. Intestinal tissue metabolism of 2NPPD was compared to skin metabolism since toxicology data from oral 2NPPD studies will be used for future safety assessment purposes. Absorption was measured over 24 h by using flow-through diffusion cells with a receptor fluid consisting of Hepes-buffered Hank's balanced salt solution. Dosing vehicles were applied to skin and intestine in the diffusion cells for 30 min. 2NPPD metabolites were determined by high-performance liquid chromatography methodology. In human skin, the percentages of total applied dose absorbed (receptor fluid + skin) over 24 h were 9.2 +/- 5.7 (mean +/- SD) and 9.5 +/- 3.2 for the ethanol and semipermanent vehicles, respectively, with approximately 3% remaining in skin. In rat skin, the percentages of total applied dose absorbed over 24 h were 9.3 +/- 1.2 (mean +/- SE), 6.9 +/- 1.2, and 4.2 +/- 0.1 for the ethanol, semipermanent, and permanent formulation vehicles, respectively, with approximately 3% remaining in skin. In rat intestinal tissue, the percentage of total applied dose absorbed over 24 h was 10.9 +/- 1.2, with approximately 5% remaining in the tissue. In human and rat skin, 2NPPD was metabolized to triaminobenzene and N4-acetyl-2NPPD. 2NPPD was also metabolized to a sulfated 2NPPD metabolite in rat skin, but not in human skin. 2NPPD was extensively metabolized in both human and rat skin with ethanol application; metabolism was not as extensive with a semipermanent formulation application. In rat intestinal tissue, 62% of 2NPPD was metabolized upon absorption to triaminobenzene and N4-acetyl-2NPPD. Differences in the metabolic profiles (proportion of each metabolite formed) were found between the skin and intestinal tissue. These results suggest that 2NPPD is rapidly absorbed and extensively metabolized in both skin and intestinal tissue. The extent of metabolism and the metabolic profile were found to be species-, tissue-, and dosing vehicle-dependent. Metabolism information will be useful in predicting the extent of 2NPPD and/or 2NPPD metabolite systemic absorption relative to a dermal exposure, which will improve the health hazard assessment of 2NPPD.