Barium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate

Carcinogenicity

Description of key information

Feeding studies on carcinogenic properties in rats and mice are available for the sodium salt of Pigment Red 57:1 (CTFA 1981a and b). Drinking water studies on carcinogenic properties in rats and mice are available Barium chloride (US NTP 1994). All studies are comparable to OECD testing guideline 451 and 453. No indication of carcinogenic properties was observed after life-long feeding of 0, 0.05, 1 and 5 % in the diet to mice and after 0.05, 0.3 and 2.0 % in the diet to rats. No indication of carcinogic properties were observed upon drinking water application at 2500 ppm. No indication of carcinogenic properties was observed in a skin painting study in mice with 50 mg/kg bw of Pigment Red 57:1 (Carson 1984). The substance is therefore considered to be non carcinogenic.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for carcinogenicity under Regulation (EC) No. 1272/2008.

Additional information

Adequate and reliable data on carcinogenicity is available for both Ba²⁺and the structural analogue of the organic anion.

The available experimental data on the sodium salt of the organic anion (Pigment Red 57) is adequate in design in reporting to allow hazard assessment of the organic part of the pigment. Pigment Red 57:1 differs by the absence of a chlorine substituent at the sulfonated phenyl ring.

The study in rat was designed to meet US FDA requirements for long-term feeding studies, it combines a fertility element, in-utero-exposure and long-term exposure of the offspring (CTFA 1981). All parameters required for OECD testing guideline 453 are addressed. The design of the study in mice meets all requirements of OECD testing guideline 451 (CTFA 1981). The purity of the test substance was reported to be 95% and stability in the feed was verified analytically. The studies were initiated prior to the introduction of Good Laboratory Practice in 1981. During the course of the study, GLP was introduced and so the last part was performed under GLP. 

The sodium salt is of better water solubility that the divalent BONA metal laked salts and may be absorbed to a lesser extent. In the chronic feeding studies systemic availability of the sodium salt was confirmed by a dose-dependent colouration of urine. Considering the high doses applied in the feed, the studies with the sodium salt are adequate for hazard assessment of the organic anion of Pigment Red 57:1.

No indication of genotoxicity of Pigment Red 57:1 was observed in in-vitro studies.

 

No indication of carcinogenic properties was observed in a skin painting study in mice with Pigment Red 57:1 (1984). The investigation was performed prior to introduction of GLP. Limited details are given in the literature publication. The study was designed by thecompetent authority and an industry association to assess the safety of the use in lipstick. For 18 months, mice were given 0.1 ml of an aqueous solution of 1% onto an area of 6 cm²twice per week. This corresponds to a dose of 1 mg per mouse (50 mg/kg bw) per treatment. Full histopathology was only performed for 5 of 50 animals per dose group.

No carcinogenicity hazard of Barium is derived from two GLP-compliant chronic drinking water studies with Barium chloride dihydrate (CAS10326-27-9 ) in rats and mice at concentrations of 500, 1250 or 2500 ppm (US NTP 1994). For both species, doses were chosen based on reduction in drinking water consumption and toxicity observed after drinking water application at 4000 ppm for 13 weeks. Based on drinking water consumption, the average uptake of the highest dose was 60 and 75 mg/kg bw for males and female rats, respectively and 160 and 200 mg/kg bw for male and female mice, respectively. Systemic availability of Barium was confirmed by monitoring of serum concentrations. Stability of the application solution was verified analytically. Exposure was 104 weeks or longer. For mice, but not for rats, a reduction in survival rate was recorded for the highest dose group. Reduction in survival of mice was linked to renal toxicity.