Chromate(2-), [3-[4,5-dihydro-4-[(2-hydroxy-5-nitrophenyl)azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulfonato(3-)][2,4-dihydro-4-[(2-hydroxy-5-nitrophenyl)azo]-5-methyl-2-phenyl-3H-pyrazol-3-onato(2-)]-, sodium

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

One study on analogue substance 1 was performed for in-vivo skin sensitization following OECD 406 (Huntsman, 1995).

The test was performed in the albino Hartley guinea-pig, to evaluate skin sensitisation of the test substance using the GPMT protocol according to Magusson and Kligman. In total 30 animals of both sexes were used, allocated to one control group of 10 animals (induction : vehicle - challenge : test article) and one treated group of 20 animals (induction and challenge : test article).

Animals were exposed to test article by 3 series of 2 X 0.1 ml injections. Test solution was made as 0.1% (W/W) solution in water for injection.

During the preliminary study, the test article tinted the skin of the animals thus making observations of erythema impossible. Nevertheless, as no oedema was noted, a skin painting was performed during the main study on Day 8, with 0.5 ml of sodium lauryl sulphate at 10% (W/W) in Codex paraffin to create irritation.

After a rest period of 11 days, a challenge was performed with the topical occlusive application for 24 h in treated and control group with the test article in a 1% (W/W) solution in water for injection and at the dose level of 0.5 ml (Maximum Non-irritant concentration)

The cutaneous macroscopic examination was performed 24 and 48 h after removal of the patches to the challenge application site, according to the Magnusson & Kligman scale. As the test article tinted the skin of the animals, thus making observations of erythema impossible, histopathological examination of the skin were performed for all the animals of the treated and control groups.

Signs of irritation were noted during induction after application of sodium lauryl sulphate in both groups. After challenge, the macroscopic and histopathological examinations did not reveal any lesion of delayed hypersensitivity in the 20 treated animals. No relevant cutaneous abnormality was noted in the 10 guinea-pigs examined in the control group.

From the results obtained under the experimental conditions employed, the test article did not provoke any reaction of cutaneous sensitization in the animals examined.

Hence, the test substance is regarded as non-sensitizer.

Based on the read across considerations same results apply to Acid Orange 144.

Justification for classification or non-classification

According to Regulation 1272/2008 a substance tested following OECD 406 (GPMT) is classified as:

skin sens cat 1: < 0.1 intradermal,                           >30%

                                >0.1 to <1% intradermal,           >60%

Skin sens cat 2: >0.1 to <1% intradermal              >30 to <60%

                               >1% intradermal                             >30%

Based on the above results the substance is not classified as skin sensitizer.