Reaction products of diazotized 2-amino-4-(methylsulfonyl)-phenol with 2-(3-Chlorophenyl)-2,4-dihydro-5-methyl-3H-pyrazol-3-one and Methyl-7-hydroxy-1-naphthylcarbamate – and chromium (III) 2:1, salted by ammonium, sodium and acid

Endpoint summary

Description of key information

The substance is not irritating to rabbit skin  (Ciba 1972). It causes mild transient irritation of rabbit conjunctivae (Ciba 1972). No indication of eye irrtiation was observed in two in-vitro studies (BCOP, EpiOcular, BASF 2011a and b).

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation:

Six English Silver rabbits were tested for skin irritation of the test substance in a Draize test (CIBA, 1972). The substance was applied occlusively on intact rabbit skin for 24 hours. Afterwards the skin was scored according to the Draize scheme at 24 h and 72 h. No findings were observed. The exposure time was 24 h instead of 4 h, and no observation was performed 1 h and 48 h after patch removal. Nevertheless, the data given were sufficient for assessment. The substance had no potential for skin irritation under the test conditions used.

Eye irritation:

For the determination of the eye irritation potential, a weight-of-evidence approach is used because the scoring system of the available animal study does not allow conclusion on classification and labelling. Two in-vitro studies for eye irritation were performed for clarification.

The eye irritation test in rabbits following a study protocol described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics (1959) of the US Association of Food and Drug Officials (AFDO) (Ciba 1972). The procedure is similar to OECD testing guideline 405, but the scoring system could not be translated into current classification and labelling criteria. Eye reactions were scored after 1, 2, 3, 4, and 7 days. Six animals were used, whereby in 3 of them rinsing was performed 30 seconds after treatment. No effects on cornea and iris were observed at all time points in all animals. The primary-irritation index for the conjunctivae was 6.1 (Mean of all animals, with and without rinsing). All effects on the conjunctivae had disappeared at day 7 of the observation period. These effects indicate, that the substance has the potential to be slightly irritating to the eye.

To assess whether the substance had the potential to be highly irritating, the BCOP (OECD 437, GLP) assay was performed (BASF 2011a). Two experiments were performed because the test item was difficult to remove from the cornea and not all corneas could be scored. Overall, four out of six corneas were available for scoring. Based on the IVIS score of 33, the substance is considered to be not highly irritating. The cut-off IVIS score is 55.

The EpiOcularTM assay was used to distinguish between non irritating and irritating properties. This assay has undergone in-house validation at BASF experimental toxicology. It is based on the toxicity to reconstituted human cornea. in vitro. The assay had to be adapted because the test item is a colorant and interfered with the MTT assay. Based on the viability of 86% after treatment, the substance is considered to be non irritating to eyes.

In the animal study, irritation of conjunctivae occurred during the first 72 hours and findings were reversilbe within 7 days. The severety of the conjunctivae findings could not evaluated. Considering that the two in-vitro studies do not indicate a hazard for eye irritation, the overall conclusion in the weight-of-evidence assessment is that the substance is not irritating to eyes.

In the animal study, discoloration of the eyes by the test item was not observed. This is consistent with the poor water solubility. Therefore, the coloring effect observed in the in-vitro studies is not relevant for classification and labelling.

In a supporting study the substance was tested as a 1% solution in the eye of 3 rabbits (IBT, 1958). The study protocol was also based on the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics (1959) of the US Association of Food and Drug Officials (AFDO). No rinsing was performed and the eyes were observed 24, 48, and 72 hours after instillation. No effects on cornea, iris and conjunctivae were observed at all time points in all animals. Thus the substance is not irritating to the eye under the chosen test conditions.

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 skin or eye irritation under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC.

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 skin or eye irritation under Regulation (EC) No. 1272/2008, as amended for the second time in Directive EC 286/2011.