Tetra-sodium/lithium 4,4'-bis-(8-amino-3,6-disulfonato-1-naphthol-2-ylazo)-3-methylazobenzene

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In a dermal sensitization study performed according to the OECD guideline 406 (RCC 1990) guinea pigs were used to test for contact sensitization of the test article. The control group consisted of 10 animals and the test group was composed of 20 animals. Intradermal inductions were performed with a 5%-solution of the test article. One week later, topical inductions were carried out under occlusive conditions for 48 hours with a 15%-solution of the test article. Following a 2 week treatment free interval, challenge exposures were performed epicutaneously (occlusive, 24 hours) with a 10%-solution of the test article. Evaluation of the skin reactions was performed 24 and 48 hours after challenge exposures. At 24 and 48-hour readings, erythema were found in 6 out of 20 and 4 out of 20 animals, respectively, in response to a 10% test article dilution. In a second challenge at the 24-hour reading, erythema were found in 2 out of 20 animals in response to a 10% test article dilution. No erythema was found in response to treatment with physiological saline alone. Assays with the positive control substance (formaldehyde-solution) performed regularly in the same laboratory caused the expected reactions. Based on this result, the test article is considered to be a skin sensitizer.

In two further dermal sensitization studies performed according to the OECD guideline 406 (RCC 1991 and ARC 2002), no positive skin reactions in any animal at any reading time were observed.

 

The sensitization potential of the test substance was also evaluated in a Local Lymph Node Assay (LLNA) performed under GLP according to OECD guideline 429, where the dorsal part of the ears of five female CBA mice per group were treated with three daily applications of 25 µl of a concentrations of 5, 10 and 22%, respectively (ARC 2002). On study day five, the mice were injected intravenously with 20μCi of 3HTdR in 250μl of sterile saline into a tail vein and sacrificed five hours later to remove the auricular lymph nodes. Analysis of the mean stimulation indices SI (fold of change as compared to the vehicle control) revealed a SI of all tested test substance concentrations < 3. Therefore the test substance is regarded as a non-sensitizer in the LLNA according to the OECD-Guideline 429.

 

Overall, the test article is regarded as a mild sensitizer based on the positive maximization test (RCC, 1990) and requires classification according to directive 67/548/EEC and Regulation 1272/200 with R43 and H317, respectively.

 

Migrated from Short description of key information:
Sensitization
- skin: sensitizing (OECD 406, RCC 1990)
- skin: not sensitizing (OECD 429, ARC 2002)

Respiratory sensitisation

Endpoint conclusion

Additional information:

Migrated from Short description of key information:
No experimental data is available regarding respiratory sensitization.

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under 67/548/EEC and Regulation 1272/2008. As a result of a positive GPMT the substance requires classification with R43 and H317 (Cat 1B).