Evaluation of the toxicity and carcinogenicity of hair dyes

Micellar enhanced chromatographic separation of selected hazardous chemical present in hair dye and their detection in formulations and swab, including assessment of damage caused to cuticle of hair shaft

Hydroquinone (HQ), resorcinol (RS), m-aminophenol (m-AMP) and p-phenylenediamine (p-PPD) are aromatic compounds which are generally used in hair dyes to provide different colours to hair. In European Union the concentrations of HQ, RS, m-AMP and p-PPD is regulated in hair dyes and other cosmetic products by EU commission regulation EU/2019/831. This legislation is generally exercised because all these compounds are toxic and may cause severe allergies when used regularly. However in India no such regulations exist to monitor these toxic compounds in hair dyes therefore in this study a simple, rapid, economical and ecofriendly micellar liquid chromatographic (MLC) technique has been developed which can monitor all the selected toxic compounds simultaneously. HQ and RS are positional isomers and are difficult to be separated by HPLC whereas with the developed MLC method it was well separated and detected. The developed MLC technique has been applied to detect and quantify selected analytes in oxidative and non-oxidative hair dyes and swab samples from the scalp. The simultaneous separation of selected analytes was performed in mobile phase 0.09 M SDS, 0.01 M NaH2PO4-2% v/v 1-butanol at pH 7 running through C18 column under isocratic mode at 1 mL/min. flow rate. All the analytes were eluted within 6 min. The present method has been validated following the EURCHEM Guideline, 2014 in terms of calibration range (0.08-15 µg/mL), limit of detection (0.01-0.09 µg/mL), limit of quantification (0.08-0.35 µg/mL), accuracy (<5.6%), precision (91-105%) and robustness (<5.8%). The selected compounds in hair dye formulation were found in the range of 0.06-12.2 µg/mL (when diluted 25 times). Hair dyes persistence study was conducted up to 10 days from the day of application on the scalp, suggesting that the dyes were not completely washed off and were retained on the scalp for more than one week. SEM analysis of dyed hair revealed that hair are severely damaged due to use of dyes. The advantage of the developed method is that it could easily be adopted by quality control and cosmetic laboratories for quality control and check for the simultaneous separation of positional isomers together with two other aromatic compounds.

4-Chloro-1,2-phenylenediamine induced structural perturbation and genotoxic aggregation in human serum albumin

4-Chloro-1,2-phenylenediamine (4-Cl-OPD) is a halogenated aromatic diamine used as a precursor in permanent hair color production. Despite its well-documented mutagenic and carcinogenic effects in various in vitro and in vivo models, its role in fibrillar aggregate formation and their genotoxic effect in therapeutic proteins has received less attention. The significance of human serum albumin (HSA) arises from its involvement in bio-regulatory and transport processes. HSA misfolding and aggregation are responsible for some of the most frequent neurodegenerative disorders. We used various complementary approaches to track the formation of amyloid fibrils and their genotoxic effect. Molecular dynamics study demonstrated the complex stability. The impact of 4-Cl-OPD on the structural dynamics of HSA was confirmed by Raman spectroscopy, X-ray diffraction, HPLC and SDS-PAGE. Fibrilllar aggregates were investigated using Congo red assay, DLS, and SEM. The genotoxic nature of 4-Cl-OPD was confirmed using plasmid nicking assay and DAPI staining, which revealed DNA damage and cell apoptosis. 4-Cl-OPD provides a model system for studying fibrillar aggregation and their genotoxic potential in the current investigation. Future studies should investigate the inhibition of the aggregation/fibrillation process, which may yield valuable clinical insights.

Final Report On the Safety Assessment of Hc Yellow No. 4

HC Yellow No. 4 is a colorant for use mostly in hair dyes and colors, but also in a few hair tints. Concentrations at which the ingredient is used range from 0.1 % to 1.0%. Confusion has existed regarding the proper structure for this ingredient, but was resolved through additional analysis; the correct CAS number is 59820-43-8. Commercially available HC Yellow No. 4 may contain a nitroaniline impurity. Percutaneous absorption studies using commercial products containing 1% HC Yellow No. 4 found little absorption. Body weight decreases were noted in short-term oral toxicity studies and in a subchronic oral toxicity study. HC Yellow No. 4 did not produce irritation, sensitization, or photosensitization in animal tests (primarily using guinea pigs). In some feeding studies, fetal toxicity was observed, but no such effect was found in other feeding studies. HC Yellow No. 4 was mutagenic in several assays, but no evidence of carcinogenesis was found in oral or dermal studies. Two repeated insult patch tests, totalling over 200 human volunteers, found no sensitization reactions. While there was concern expressed over the reproduction and developmental toxicity found in feeding studies, such adverse responses would not be expected from the use of this ingredient in hair coloring products because so little HC Yellow No. 4 is absorbed. The presence of a low level of nitroaniline derivative impurity (0.3 to 7%) is not considered to present a human health risk because the products containing HC Yellow No. 4 are used in a brief and discontinuous manner, followed by rinsing. On the basis of the available data, therefore, it is concluded that HC Yellow No. 4 is safe as a hair colorant in the present practices of use.

Final Report On the Safety Assessment of Hc Orange No. 11

HC Orange No. 1 is used as a colorant in semipermanent hair dyes. The highest concentration reported to be used is 0.15%, but information from manufacturers suggested that higher concentrations may be used in the future. Skin penetration through cadaver skin was 1.28% at 24 hours. In studies using rats, acute oral exposure studies produced little toxicity, and short-term toxicity studies produced reduced body weight and increased liver and kidney weights, relative to controls in animals fed 0.5% HC Orange No. 1. There was no evidence of reproductive or developmental toxicity in rats fed up to 1.25% HC Orange No. 1 or in a multigeneration study using rats in which 0.15% HC Orange No. 1 was painted on the skin. While evidence suggests this ingredient is a mild ocular irritant, no skin irritation, sensitization, or photosensitization was seen in animal or clinical tests. The preponderance of data (four out offive studies) indicate that this ingredient is not genotoxic. Hepatocellular and parathyroid hyperplasia were noted in the dermal carcinogenicity study, but the overall findings were clearly negative. Because the highest concentration tested that produced no significant sensitization in clinical tests was 3%, the Expert Panel concluded that safety could be assured only at levels ≤3%. The Expert Panel recognized that this concentration may be greater than that currently used in hair dye formulations.

Final Report on the Safety Assessment of HC Blue No. 2

The aromatic amine HC Blue No. 2 is used as a colorant exclusively in hair dyes. Current information indicates this ingredient is usually found in hair dyes at a concentration of ∼ 1.7%. Studies in volunteers in which HC Blue No. 2 at use concentrations was applied to the scalp, <0.1% was absorbed over a period of 30 days. National Toxicology Program oral feeding bioassays in rats and mice shows the ingredient to be relatively nontoxic. Animal studies indicate no evidence of dermal irritation, sensitization, or photosensitization, and no ocular irritation. Whereas HC Blue No. 2 is mutagenic, it was not carcinogenic in rats or in two mouse strains. Clinical data indicate minimal irritation and no sensitization. On the basis of the available data, it is concluded that HC Blue No. 2 is safe as used in cosmetic formulations (hair dyes).

6 Final Report on the Safety Assessment of p-Phenylenediamine

p-Phenylenediamine is a cosmetic hair dye intermediate used in permanent hair coloring products at concentrations of up to 5 percent (diluted 1:1 with an oxidizing agent prior to application). The extensive animal toxicity test data on p-Phenylenediamine and permanent cosmetic hair dyes containing this compound show that the degree of toxicity varies with concentration, test system and animal species. Animal data support a conclusion that this compound is neither a teratogen nor a carcinogen. Epidemiological data also support that hair dyes containing this ingredient are not carcinogenic. p-Phenylenediamine is a sensitizer and some persons may be sensitized under intended conditions of use.

For those persons not sensitized, it is concluded that p-Phenylenediamine is safe as a hair dye ingredient at the current concentrations 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 2,4-Diaminophenol and 2,4-Diaminophenol Dihydrochloride

The aromatic amines 2,4-Diaminophenol and 2,4-Diaminophenol Dihydrochloride are colorants intended for use in oxidative hair dyes. Currently, 2,4-Diaminophenol Dihydrochloride is used in three hair dyes, whereas there are no reported uses of 2,4-Diaminophenol. Chromatographic analysis of 2,4-Diaminophenol indicates that an impurity, 2-amino-4-nitrophenol, is present at a concentration of 2.7%. The oral median lethal dose (LD50) for 2,4-Diaminophenol Dihydrochloride in rats was 0.24 g/kg, with a dose-dependent renal toxicity seen in acute, short-term, subchronic and chronic toxicity tests. Renal toxicity was noted in rats at doses nine times lower than the LD50. 2,4-Diaminophenol Dihydrochloride was a skin and ocular irritant in rabbits, but not in guinea pigs, nor did it induce sensitization in guinea pigs. A dye formulation with 0.2% 2,4-Diaminophenol did not produce evidence of terato-genesis in female rats. No genotoxicity was seen in some systems, but there was evidence of mutagenesis in others. Dermal application of 2,4-Diaminophenol was not carcinogenic in Swiss Webster mice in a 23-month study, even with the presence of a 2.7% 2-amino-4-nitrophenol impurity. Administration of 2,4-Diaminophenol Dihydrochloride by gavage produced no evidence of carcinogenic activity in National Toxicology Program bioassays in male and female F344/N rats and female B6C3F1 mice. There was an increase in renal tubular cell adenomas in male B6C3F1 mice at the highest dose level, 38 mg/kg. On the basis of the animal data presented in the report, the expected use of the product, and acknowledging the labeling requirements for hair dyes if they are to qualify for an exemption from the Food and Drug Administration, it is concluded that 2,4-Diaminophenol and 2,4-Diaminophenol Dihydrochloride are safe for use in hair dyes at concentrations up to 0.2% (as the free base).

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

Animal data on 2NPPD and 4NOPD and cosmetic hair dyes containing these ingredients suggest that both compounds were nonirritating to rabbit skin and eyes, but were sensitizers on guinea pig skin. The results of repeated insult patch tests with hair dye products containing these ingredients indicated that neither was an irritant or a sensitizer to human subjects as normally used. In the absence of human data on the pure compounds, however, 2NPPD and 4NOPD are considered to be potential human sensitizers.

Topically applied 2NPPD and 4NOPD are absorbed by experimental animals. Neither embryotoxicity nor teratogenicity was observed in animal studies when hair dyes containing 2NPPD and 4NOPD were applied to the skin. Both ingredients were mutagenic in some bacterial and in vitro mammalian systems; both compounds had some genotoxic activity. In feeding studies in mice and rats, only 2NPPD induced hepatocellular tumors in female mice. Both compounds were noncarcinogenic in male mice and in rats of either sex. Epidemiological data have not demonstrated a carcinogenic effect in man for hair dyes.

For those persons not sensitized, it is concluded that 2NPPD and 4NOPD are safe as hair dye ingredients at the current concentration of use.

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.

Final Report on the Safety Assessment of Sodium Dodecylbenzenesulfonate/TEA-Dodecylbenzenesulfonate/ Sodium Decylbenzenesulfonate

The oral LD50 for Sodium Dodecylbenzenesulfonate (SDDBS) in rats was 1.26 g/kg. No significant toxic effects were observed when rats were given oral doses of 1000 ppm SDDBS in water. No systemic toxicity was observed in rabbits given dermal applications of ≤10% SDDBS to abraded skin for 28 days; severe dermal irritation was observed at the application site. Mild necrosis of intestinal mucosa with hemosiderosis of the spleen, liver, and kidneys was observed in rats given a varying dosage of 2.5–5.0 ml/kg/day of a formulation containing 15% SDDBS for a total of 22 weeks; lesions were not observed for rats given 0.5 ml/kg/day. Renal damage was observed in rats dosed orally with ≤0.6% SDDBS for 6 months. For dogs fed ≤1000 mg/kg/day of a formulation containing 15% SDDBS in the diet for 6 months, hemorrhagic necrosis of the intestine and infiltration of inflammatory cells were observed at 10 mg/kg and hemosiderosis of the liver and spleen was observed at 100 and 1000 mg/kg. SDDBS, adjusted to 15% active and a p H of 7.0, applied to intact and abraded sites was severely irritating. A solution containing 1.9% SDDBS and 1.9% tallow alkyl ethoxylate sulfate was moderately irritating to the skin of rabbits. This compound was not a sensitizer when tested at low concentrations. Concentrations of ≥5% Linear Alkylbenzene Sulfonate (LAS) were irritants to the eyes of rabbits; ≤0.1 % LAS produced mild to no irritation. (LAS is a commercial preparation that has the average molecular weight of SDDBS.) No reproductive effects were produced by dermal application of LAS or TEA-DDBS or by oral administration of LAS. The results of mutagenic assays using SDDBS were negative. Dermal carcinogenicity studies using LAS and TEA-DDBS and oral carcinogenicity studies using SDDBS and LAS were negative. On the basis of the animal and clinical data presented in this report, it is concluded that Sodium Dodecylbenzenesulfonate, TEA-Dodecylbenzenesulfonate, and Sodium Decylbenzenesulfonate are safe as cosmetic ingredients in the present practices of use. The full report includes a discussion on how the various types of safety test data were interpreted, both individually and collectively.

Cellular and molecular damage of Phanerochaete chrysosporium by the oxidation hair dyes

INTRODUCTION

The toxic effect of the oxidation hair dyes on Phanerochaete chrysosporium was investigated by exposure of this fungus in a nitrogen-limited culture medium to various concentrations of the oxidation hair dyes.

RESULTS

The results showed that both the size and the dry weight of the mycelial pellets of P. chrysosporium could be reduced when the concentration of the oxidation hair dyes was higher than 300 mg/L. By using the AFLP analysis and the UPGMA dendrogram, the DNA damage of P. chrysosporium by the oxidation hair dyes was also detected. Comparing with that in the control, the percent polymorphism under different concentrations of the oxidation hair dyes increased. In the meantime, the DNA similarity was decreased, which meant that the DNA damage was aggravated with an increase in the concentrations of the oxidation hair dyes.

CONCLUSION

Thus, as an environmental pollutant, the oxidation hair dyes have a toxic effect on P. chrysosporium at both cellular and molecular levels.

Safety assessment of personal care products/cosmetics and their ingredients

We attempt to review the safety assessment of personal care products (PCP) and ingredients that are representative and pose complex safety issues. PCP are generally applied to human skin and mainly produce local exposure, although skin penetration or use in the oral cavity, on the face, lips, eyes and mucosa may also produce human systemic exposure. In the EU, US and Japan, the safety of PCP is regulated under cosmetic and/or drug regulations. Oxidative hair dyes contain arylamines, the most chemically reactive ingredients of PCP. Although arylamines have an allergic potential, taking into account the high number of consumers exposed, the incidence and prevalence of hair dye allergy appears to be low and stable. A recent (2001) epidemiology study suggested an association of oxidative hair dye use and increased bladder cancer risk in consumers, although this was not confirmed by subsequent or previous epidemiologic investigations. The results of genetic toxicity, carcinogenicity and reproductive toxicity studies suggest that modern hair dyes and their ingredients pose no genotoxic, carcinogenic or reproductive risk. Recent reports suggest that arylamines contained in oxidative hair dyes are N-acetylated in human or mammalian skin resulting in systemic exposure to traces of detoxified, i.e. non-genotoxic, metabolites, whereas human hepatocytes were unable to transform hair dye arylamines to potentially carcinogenic metabolites. An expert panel of the International Agency on Research of Cancer (IARC) concluded that there is no evidence for a causal association of hair dye exposure with an elevated cancer risk in consumers. Ultraviolet filters have important benefits by protecting the consumer against adverse effects of UV radiation; these substances undergo a stringent safety evaluation under current international regulations prior to their marketing. Concerns were also raised about the safety of solid nanoparticles in PCP, mainly TiO(2) and ZnO in sunscreens. However, current evidence suggests that these particles are non-toxic, do not penetrate into or through normal or compromised human skin and, therefore, pose no risk to human health. The increasing use of natural plant ingredients in personal care products raised new safety issues that require novel approaches to their safety evaluation similar to those of plant-derived food ingredients. For example, the Threshold of Toxicological Concern (TTC) is a promising tool to assess the safety of substances present at trace levels as well as minor ingredients of plant-derived substances. The potential human systemic exposure to PCP ingredients is increasingly estimated on the basis of in vitro skin penetration data. However, new evidence suggests that the in vitro test may overestimate human systemic exposure to PCP ingredients due to the absence of metabolism in cadaver skin or misclassification of skin residues that, in vivo, remain in the stratum corneum or hair follicle openings, i.e. outside the living skin. Overall, today's safety assessment of PCP and their ingredients is not only based on science, but also on their respective regulatory status as well as other issues, such as the ethics of animal testing. Nevertheless, the record shows that today's PCP are safe and offer multiple benefits to quality of life and health of the consumer. In the interest of all stakeholders, consumers, regulatory bodies and producers, there is an urgent need for an international harmonization on the status and safety requirements of these products and their ingredients.

The debate on carcinogenicity of permanent hair dyes: new insights

Oxidative (permanent) hair dyes contain one or several "primary intermediates" (e.g., p-phenylenediamines, p-aminophenols) and "couplers" (e.g., m-aminophenols, m-hydroxyphenols). In the presence of peroxide, the primary intermediate(s) and the coupler(s) undergo a chemical reaction to form colored oligomers. In the 1970s a number of aromatic amines used in oxidative hair dyes were identified as mutagenic and/or carcinogenic in rodents after lifetime oral administration. In response, regulatory action was taken, and some hair dye ingredients were banned in the European Union. Although recent results suggest that the main "primary intermediate" of oxidative hair dyes, p-phenylenediamine, has a weak genotoxic potential in vitro, it was not mutagenic in a mixture with nonmutagenic couplers, if tested under conditions comparable to those of practical use. Under conditions of use of permanent hair dyes, between 0.1 and 0.5% of the applied p-phenylenediamine may be absorbed through the skin. Acetylation in the skin is a key metabolic step for the primary intermediates p-phenylenediamine and p-aminophenol. Because of the involvement of aromatic amines, the discussion on the carcinogenicity of hair dyes in humans has been focused on urothelial cancer. Numerous epidemiological studies have investigated the risk of bladder cancer associated with the profession as a hairdresser, as well as the risk to consumers of hair dyes. Although some earlier studies suggested an overrepresentation of bladder cancer in male hairdressers, the majority of modern studies do not show an increase in relevant bladder cancer risk for professional or personal use of oxidative hair dyes. Today, there seems to be no relevant bladder cancer risk from the use of oxidative hair dyes. Such a conclusion can be derived from new toxicokinetic and metabolism investigations and is in general accordance with current epidemiological data. Human urothelial cancers, chemically induced by aromatic amines, have typical latency times often longer than 20 years. Since earlier exposures could have an impact decades later, the possibility of bladder cancer in hairdressers having intensively worked with permanent hair dyes during earlier decades (prior to the 1980s) should be taken into account.

Final report on the safety assessment of 6-Amino-m-Cresol, 6-Amino-o-Cresol, 4-Amino-m-Cresol, 5-Amino-4-Chloro-o-Cresol, 5-Amino-6-Chloro-o-Cresol, and 4-Chloro-2-Aminophenol

Each of these ingredients function as hair colorants. 5-Amino-4-Chloro-o-Cresol and 5-Amino-6-Chloro-o-Cresol are identified as oxidative hair dyes, that is, they are combined with an oxidizing agent before being applied to the hair. 6-Amino-m-Cresol, 6-Amino-o-Cresol, 4-Amino-m-Cresol, and 5-Amino-4-Chloro-o-Cresol are used in oxidative hair dyes, but it is not known if they are also used in nonoxidative (semipermanent) hair dyes. No toxicologically significant impurities are present with these two ingredients. To supplement the safety test data on these ingredients, available data on related ingredients (4-amino-2-hydroxytoluene and p-,m-, and o-aminophenol) previously found safe as used by the Cosmetic Ingredient Review (CIR) Expert Panel were summarized. 5-Amino-4-Chloro-o-Cresol and 5-Amino-6-Chloro-o-Cresol do not absorb significant ultraviolet radiation in the UVB region and none in the UVA region, although 4-Amino-m-Cresol had a symmetrical UV absorption peak at 300 nm. Percutaneous penetration of 5-Amino-4-Chloro-o-Cresol and 5-Amino-6-Chloro-o-Cresol alone was significant, but when combined with oxidative developer, skin absorption was extremely low. Both of these dyes are excreted rapidly via the urine. Repeated exposure of animal skin to 5-Amino-4-Chloro-o-Cresol and 5-Amino-6-Chloro-o-Cresol failed to produce any cumulative irritation and single exposures up to 10%were not irritating to animal skin. 5-Amino-4-Chloro-o-Cresol and 5-Amino-6-Chloro-o-Cresol combined with oxidizer were not sensitizers in guinea pig maximization tests. Ocular irritation resulted from exposure of animals to undiluted 5-Amino-4-Chloro-o-Cresol, but not to a 5%solution. Only minor irritation was observed with 5%5-Amino-6-Chloro-o-Cresol. Subchronic toxicity testing in animals using 5-Amino-4-Chloro-o-Cresol, 5-Amino-6-Chloro-o-Cresol, and 4-Amino-m-Cresol did not yield any adverse reactions. 6-Amino-m-Cresol and 4-Amino-m-Cresol were generally not mutagenic in in vitro and in vivo tests. Exposure to 5-Amino-4-Chloro-o-Cresol, 5-Amino-6-Chloro-o-Cresol, 6-Amino-m-Cresol and 4-Amino-m-Cresol from cosmetics were several orders of magnitude below developmental toxicity no-observed-adverse effect levels (NOAELs). Although irritation data on several ingredients are absent, products containing these ingredients must include a caution statement and patch test instructions for determining whether the product causes skin irritation. The Expert Panel expects that following this procedure would identify individuals who would have an adverse reaction and allow them to avoid significant exposures. These compounds, when tested alone, are moderate skin sensitizers, but when combined with the developer, these ingredients are not sensitizers in animal tests. This information, coupled with the available animal test data, supports the safety of these ingredients in oxidative hair dyes. In the absence of systemic toxicity data, however, the available data are insufficient to support the safety of 6-Amino-o-Cresol and 4-Chloro-2-Aminophenol in semipermanent hair dyes. The types of data required for these two ingredients for this use include (1) physical and chemical properties, including the octanol/water partition coefficient; (2) impurities data, especially regarding the presence of m-cresol, other organic molecules, and heavy metals; (3) data demonstrating that the metabolism is similar to that of 4-amino-2-hydroxytoluene and/or p-,m-, and o-aminophenol, or 28-day dermal toxicity with histopathology, dermal reproductive toxicity data, and an in vitro genotoxicity study for 6-Amino-o-Cresol and one genotoxicity study in a mammalian system; if positive, a 2-year dermal carcinogenicity study using National Toxicology Program methods may be needed.

Toxicity and human health risk of hair dyes

Hair dyes and their ingredients have moderate to low acute toxicity. Human poisoning accidents are rare and have only been reported following oral ingestion. Contact sensitisation to hair dyes has been a safety issue, mainly as a consequence of unprotected professional exposure. Although the use of hair dyes has dramatically increased in industrialised countries during the last decades, the prevalence of sensitisation to hair dyes in the general and professional populations has stabilised or declined. In vitro genotoxicity tests on hair dye ingredients frequently had positive results, although their correlation with in vivo carcinogenicity for the chemical class of oxidative hair dye ingredients (aromatic amines) is uncertain. Positive in vivo genotoxicity results on hair dyes are rare. Studies in man found no evidence of genotoxic effects of hair dyes or their ingredients. On the basis of mechanistic studies, some in vivo positive hair dye ingredients (p-aminophenol, Lawsone) have been shown to pose no or negligible risk to human health. Although a recent case-control epidemiology study suggested an association of hair dye use and bladder cancer, a number of other studies, including prospective investigations on large populations, found no or negative correlations for bladder or other cancers. Although in vivo topical carcinogenicity studies on hair dye ingredients or commercial formulations yielded no evidence for systemic toxicity or carcinogenicity, oral carcinogenicity studies on hair dye ingredients at oral doses up to the maximum tolerated dose (MTD) suggested that some ingredients are carcinogenic in rodents. Human systemic exposure to various (14)C-labelled oxidative hair dyes under conditions of use was below 1.0% of the amount applied. Conservative risk assessments suggested no or negligible cancer risk, including for ingredients that were found to be positive in oral carcinogenicity studies. The results of reproductive toxicity studies and epidemiological investigations suggested that hair dyes and their ingredients pose no risk of adverse reproductive effects. In conclusion, the weight of evidence suggests that consumer or professional exposure to hair dyes poses no carcinogenic or other human health risks.

Genotoxicity studies on professional hair colorists exposed to oxidation hair dyes

The cytogenic repercussions of occupational exposure to oxidation hair dyes were assessed by using three assays in professional hair colorists. The assays were sister chromatid exchanges (SCE) in circulating lymphocytes to evaluate the interchange of DNA replication products at apparently homologous chromosomal loci, single cell gel electrophoretic (SCGE) assay to detect the presence of DNA strand breaks/alkali-labile damage, and the Ames assay using Salmonella typhimurium strain TA98 to detect the urine mutagenicity. The ability of these assays to detect genetic damage caused by oxidation hair dyes in man compared with closely matched controls produced the following findings. (i) The SCE assay could not detect the mutagenic effect in lymphocytes of exposed subjects from whom complete data were obtained. However, subjects (controls and exposed) with a history of smoking had slightly increased SCEs than the non-smokers in both groups. (ii) The extent of DNA migration (SCGE assay) did not distinguish between the samples in either the exposed or control subjects. Like the SCE results, the exposed and control smoker subjects showed a greater proportion of damaged lymphocytes with apparent migration of DNA. (iii) No clear differences in the mutagenic activity of the urine samples were observed between the exposed and control subjects. But, pooling exposed and controls together, a positive and significant variation in the urinary mutagenic effect was observed with the number of cigarettes smoked per day.

Final Report On the Safety Assessment of m-Phenylenediamine and m-Phenylenediamine Sulfate1

The ingredients m-Phenylenediamine and m-Phenylenediamine Sulfate are aromatic amines that function as hair colorants in cosmetic products. Both are currently used in hair dye products at concentrations of up to 3%. Percutaneous absorption of m-Phenylenediamine has been demonstrated in animals. Three metabolites excreted in urine have been identified. The oral LD50 of m-Phenylenediamine in rats is between 360 and 650 mg/kg. Subchronic studies in rats (oral) indicated some lesions in the liver but no kidney injury, while one study in rabbits (dermal) indicated some liver and kidney toxicity. Another dermal study in rabbits failed to show any liver or kidney toxicity. Skin irritation and sensitization were found in guinea pigs exposed to m-Phenylenediamine. Clinical data indicated some evidence of sensitization. A short-term study in rats (oral) reported an absence of any neurotoxicity. One study in female rats identified fetotoxicity but no evidence of terata. Other studies reported neither birth defects nor fetal deaths. Both positive and negative results were found in various mutagenesis assay systems. In studies with mice and rats, neither m-Phenylenediamine (both oral and dermal exposure) nor hair dye formulations (dermal exposure only) containing m-Phenylenediamine were carcinogenic. Based on the concentrations of m-Phenylenediamine shown to produce sensitization in animal studies, it was concluded that these ingredients can be used safely in hair dyes at concentrations of up to 10%.

Carcinogenicity and toxicity study of m-phenylenediamine administered in the drinking-water to (C57BL/6 x C3H/He)F1 mice

m-Phenylenediamine (m-PDA, CAS: 108-45-2), a component of hair-dye formulations, was administered in the drinking-water to groups of female and male (C57BL/6 x C3H/He)F1 (B6C3F1) mice at concentrations of 0.02 or 0.04% for 78 wk. All the surviving mice were killed after a further 5-7 wk on untreated drinking-water, 83-85 wk after the start of treatment. Survival of the treated mice was similar to that of the corresponding controls. Body weights were significantly lower in high-dose females and males and somewhat lower in low-dose females than in the controls. The incidences of hepatocellular tumours were low to moderate in all male groups and in the control females, but the treated groups had significantly lower incidences than the controls. A few tumours of the lungs, haematopoietic organs and other organs and tissues were observed in all female and male groups. However, there were no statistically significant increases in the incidences of tumours in these organs and tissues in m-PDA-treated mice of either sex. Under the conditions of this study m-PDA showed no carcinogenic potential in either female or male B6C3F1 mice when administered in drinking-water. No non-neoplastic changes attributable to the compound were found in the treated mice, except for the deposition of brown pigment in follicular epithelial cells of the thyroid gland and in macrophages in some organs and tissues, and pigment impregnation of the bronchioli.

Evaluation of the toxicity and carcinogenicity of hair dyes in Swiss mice

The chronic toxicologic and carcinogenic potential of two oxidative and twelve non-oxidative hair dyes has been evaluated. The dyes were skin painted up to 3 times weekly on groups of 60 male and 60 female Eppley Swiss mice. Treatments were carried out for 20 months followed by terminal sacrifice. Nine months after treatments were initiated an intermediate sacrifice of ten mice per sex per group was carried out. Body weights and survival differed little between appropriate male and female treatment and control groups. Differences between treated and control groups in absolute and relative liver and kidney weights and in hematological and urinary values were not considered to be indicative of toxicologic effects. Microscopic examinations of the skin revealed occasional hyperplasia, necrosis, ulceration and other lesions not significantly increased by dye treatment. Chronic inflammation of the skin was observed in the control and treated mice and was significantly increased by one non-oxidative dye. The predominant tumors diagnosed were liver hemangioma, lung adenoma and malignant lymphoma. There was a statistically significant increase in the incidence of malignant lymphoma in female mice in 3 treated groups when compared to control group 2, but the differences were not significant when these groups were compared to control group 1. In addition the values in these 3 groups were within the range of control values for this tumor in female mice in the Eppley colony. No other tumors occurred at significantly increased frequencies in treated mice. We conclude that toxicological and carcinogenic effects were not clearly induced by the hair dye formulations.