Disodium 2-[4-[[1-[[(2-methoxy-5-methyl-4-sulphonatophenyl)amino]carbonyl]-2-oxopropyl]azo]phenyl]-6-methylbenzothiazole-7-sulphonate

Endpoint summary

Description of key information

The test item is not a skin sensitiser under the test conditions of the LLNA and guinea pig study.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Key study

In a GLP and OECD 429 guideline compliant study, the test item was assessed for its skin sensitising potential using the Local Lymph Node Assay (LLNA) in mice.

The following test item concentrations of 5, 10, and 20% (w/w) were used.

The animals showed neither signs of systemic toxicity nor mortality during the course of the study. All animals of the high dose group showed a slight yellow coloration of the ears on day 2. Due to the colour of the test item no assessment of possible erythema was possible in all dose groups on day 3. On day 6, in all dose groups scaly ears were observed. A statistically significant or biologically relevant increase in ear weights was not observed in any treated group in comparison to the vehicle control group.

Furthermore, for BALB/c mice, a cut-off value of 1.1 for the ear weight index was reported for a positive response regarding ear skin irritation. None of the indices determined for the test item treated groups reached or exceeded this threshold.

Stimulation Indices (S.I.) of 1.0, 1.1, and 1.2 were determined with the test item at concentrations of 5, 10, and 20% (w/w) in DMSO, respectively.

A statistically significant and biologically relevant increase in radioactive disintegrations per minute (DPM) value and also in lymph node weight and cell count was not observed in any dose group in comparison to the vehicle control group. Furthermore, the cut-off value of 1.55 for a positive response regarding the lymph node cell count index reported for BALB/c mice was not reached or exceeded in any dose group.

The test item was thus not a skin sensitiser under the test conditions of this study.

Supporting study

The test substance was tested in a Guinea Pig Maximization Test (GPMT) according to the OECD TG 406 (Safepharm, 1989). The concentrations used for testing were selected on the basis of the results of a pretest.The induction phase comprises the intradermal and epicutaneous route. For the intradermal Induction, 10% (w/v) in distilled water, 10% (w/v) in Freund's Complete Adjuvant plus distilled water in the ratio 1:1 were applied. For the topical Induction, undiluted test substance were applied. In the challenge phase, 0.1 -0.2 mL of 75% (v/v) in distilled water or vehicle were applied to the test group (20 f) or the control group (10 f). No evidence of erythema was noted at the test substance and vehicle control sites of the test or control animals at the 24 and 48-hour observations. A yellow-coloured staining caused by the test substance was observed at the application site of each animal. Body weight gains of guinea pigs in the test group, between day 0 and day 24, were comparable to those observed in the control group animals over the same period. The test substance produced a 0% (0/20) sensitisation rate in this study and was classified as a non-sensitiser to guinea pig skin.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

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 (CLP). As a result the test substance is not considered to be classified for skin sensitisation under Regulation (EC) No 1272/2008, as amended for the tenth time in Regulation (EU) No 2017/776