Cobaltate(3-), bis[6-amino-5-[(2-hydroxy-3,5-dinitrophenyl)azo]-1-naphthalenesulfonato(3-)]-, sodium

Endpoint summary

Description of key information

Non sensitising to the skin.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

No data to assess the skin sensitising potential of Acid Green 104 was available, thus a read-across approach was adopted. In particular, available data on Similar Substance 01 and Similar Substance 02, i.e. cobalt complexes with 2 phenyl-azo-naphtyl ligands functionalised by similar groups, was used. Details on the read across are attached in section 13.

Similar Substance 01 was tested in Local Lymph Node Assay in mice (OECD guideline 429). Concentrations of 1 %, 2 % and 5 % w/w in DMF were used. Upon a pre-experiment, the 5 % concentration was found to be the highest concentration at which non excessive local irritation and no systemic toxicity was noted.

In the main test, no signs of systemic toxicity were noted; erythema could not be evaluated due to the colour of the substance. No statistically significant increase in ear weight (cutoff value of 1.1 in BALB/c mice) was seen.

Stimulation Indices (S.I.) of 1.27, 2.01 and 2.22 were determined at concentrations of 1, 2, and 5% (w/w) in DMF, respectively. A clear dose response was observed, but the threshold value of 3 for positive response was not reached.

A statistically significant but biologically not relevant increase in lymph node cell count was observed in the mid and highest dose group in comparison to the vehicle control group. However the cut-off value of 1.55 for a positive response in BALB/c mice was not reached in any dose group.

Overall, the substance resulted as not skin sensitiser in the LLNA assay.

A maximisation test was conducted on Similar Substance 02, using 10/females in the control group and 20/females in the test group. Upon a pretest, concentrations for induction phase and challenge application in the main test were chosen.

The intradermal injections was performed at 1 % w/v test item in water and in the FCA/physiological saline mixture. After 8 days, epidermal induction was performed with 25 % test item in vaselinum album. Challenge was carried out at day 22 and 29 at 25 % test item in vaselinum album by epidermal occlusive patch system.

Under the experimental conditions, none of the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings. Therefore, the substance resulted to be non skin sensitiser.

No positive reactions were reported in the available guinea pig maximisation test carried out on Similar Substance 02.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), skin sensitizer is a substance that will lead to an allergic response following skin contact.

In case of a local lymph node assay, a stimulation index ≥ 3 is considered as positive. Uner the test conditions, the simlulation index was far below 3 at all test concentrations (1 %, 2% and 5 %).

In case of a guinea pig maximisation test, a response of at least 30 % of the animals is considered as positive. Under the experimental conditions employed, 0 % of the animals of the test and control groups showed skin reactions 24 and 48 hours after removing the dressings.

On these bases, the substance was not classified as skin sensitiser, according to the CLP Regulation (EC 1272/2008).