Strontium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]

Endpoint summary

Additional information

Read across justification

Genotoxicity of the test substance was not examined. The test item shares high structural similarity to an analogue substance, since both are salts which differ in the respective metal cation only. Both substances are solid pigments and poor soluble in water and octanol. Therefore, it is acceptable to derive information on genotoxicity from experimental data of the analogue substance.

Procedure and observations

Pigment red 53:1 has been tested for genotoxicity in a series of Ames tests with and without metabolic activation including the Prival test (Ciba 1985, Zeiger et al 1988, Brown et al 1979, Hoechst 1985, Hoechst 1985, Hoechst 1989), in the Cytogenetic assay with V 79 cells and with ovary cells of Chinese hamsters (CHO) (Ivett et al 1989, Hoechst 1989), in the Mouse lymphoma assay (Myhr et al 1991), in the Sister chromatid exchange assay with ovary cells of Chinese hamsters (CHO) (Ivett et al 1989) and the Unscheduled DNA synthesis in rat hepatocytes (Kornbrust et al 1985). In all these in vitro studies pigment red 53:1 gave negative results. Pigment red 53:1 was also assayed for genotoxicity in vivo using the rat micronucleus test (Westmoreland and Gatehouse 1992), a rat ex vivo liver UDS assays and the SLRL-test in Drosophila. Uniformly negative results were obtained in all assays, even though large oral doses were used (up to 2 g/kg).

Discussion

In various in vitro and in vivo studies pigment red 53:1 proved to be non-genotoxic. The results suggest that the tumorigenic effects of this compound in rats are mediated through a non-genotoxic rather than a genotoxic mechanism.

Short description of key information:
Studies on genotoxicity of the test item (Sr salt) were not performed. Since both substances are salts with similar structur and similar solubility, information on mutagenicity and cytogenicity were derived from experimental data of a structural analogue (Ba salt). In several Ames test with and without prival modification conducted equivalent or according to OECD 471 no genotoxicity was seen. Also a mouse lymphoma assay and an UDS assay in rat hepatocytes yielded negative results. In two in vitro chromosome aberration assasy conducted equivalent or according to OECD guideline 473 no increase in structural chromosome aberrations was seen. An in vivo Micronucleus test according to OECD guideline 475 as well as a Drosophila SLRL and an UDS in vivo gave also no positive results. Based on the data of these studies the test substance was not considered to be genotoxic.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for genotoxicity under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC.

 

 

Classification, Labeling, 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 genotoxicity under Regulation (EC) No. 1272/2008, as amended for the second time in Directive (EC 286/2011).