Reaction mass of Cobaltate(2-), [2-[[[4-hydroxy-3-[[2-oxo-1-[(phenylamino)carbonyl]propyl]azo]phenyl]sulfonyl]amino]benzoato(3-)][2-[[2-hydroxy-5-[(phenylamino)sulfonyl]phenyl]azo]-3-oxo-N-phenylbutanamidato(2-)]-, disodium and Cobaltate(3-), bis[2-[[[4-hydroxy-3-[[2-oxo-1-[(phenylamino)carbonyl]propyl]azo]phenyl]sulfonyl]amino]benzoato(3-)]-, trisodium and sodium bis[2-[[2-hydroxy-5-[(phenylamino)sulphonyl]phenyl]azo]-3-oxo-N-phenylbutyramidato(2-)]cobaltate(1-)

Endpoint summary

Description of key information

Not skin sensitising

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

no

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Old test

Species:

guinea pig

Details on test animals and environmental conditions:

TEST ANIMALS
- Housing: 5 animals were housed in each cage.
- Diet: a standard laboratory diet was provided, ad libitum. The batch of the diet used for the study was analysed for ctremical and microbiological contaminants.
- Acclimation period: all animals were acclimatized to the environment for a period of seven days prior to the start of the study.
- Indication of any skin lesions: 24 hours prior to the test, the skin of the back was clipped by means of an electric clipper and the skin was investigated for pre-existing injuries. This was repeated on days 7 and 22. The skin was cleaned with 10 % sodium laurylsulfate on day 7.

ENVIRONMENTAL CONDITIONS
- Temperature: 23 ± 1 °C
- Relative humidity: 50 ± 5 %
- Air changes: approx. 10-15 air changes per hour.
- Photoperiod: 12 hrs dark / 12 hrs Iight.

Route:

intradermal and epicutaneous

Vehicle:

water

Concentration / amount:

5 %

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

5 %

No. of animals per dose:

20 animals per group

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal injection
- No. of exposures: test was started with three intradermal paired injections.

Epicutaneous
- Application: a patch (25 cm2) soaked with 3 mI was fixed on the clipped backs.
- Exposure period: 48 hours
- Control group: only water or adjuvant were used.

B. CHALLENGE EXPOSURE
- Day(s) after start: 21
- Exposure period: 24 hours
- Evaluation: after 24 and 48 hours respectively, the patches were removed and the resulting reactions were evaluated.

Positive control substance(s):

yes

Remarks:

1-chloro-2,4-dinitrobenzene

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5 %

No. with + reactions:

0

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

1 %

No. with + reactions:

20

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

3 ml water

No. with + reactions:

0

Total no. in group:

20

The test item administered to guinea pigs, according to the maximization test, resulted in no reaction after 24, 48 and 72 hours respectively. In contrast, DNCB, a well known sensitizer, was positive after 24, 48 and 72 hours.

It can be concluded that test substance was not a sensitizer.

Interpretation of results:

other: not classified, according to the CLP Regulation (EC) No 1272/2008

Conclusions:

Not skin sensitising

Executive summary:

60 guinea pigs were divided in three groups, 20 animals each group: one group was treated with test item; another with 1-chloro-2,4-dinitrobenzene (DNCB) as a positive control and the third group served as negative controls, treated with water and Freuds Adjuvant alone.

Test substance was dissolved with water or Adjuvant respectively to 5 % solution, which was used for the paired injection on day 1 of the study. The test was started with three intradermal paired injections; on day 8, a patch (25 cm2) soaked with 3 ml was fixed for 48 hours on the clipped backs. 21 days after the start, the flanks of the animals were clipped and on the next day a patch was fixed for 24 hours, using test item 3 ml of the 5 % solution for the treated and negative control animals.

After 24 or 48 hours respectively, the patches were removed and the resulting reactions were evaluated.

The test item administered to guinea pigs, according to the maximization test, resulted in no reaction after 24, 48 and 72 hours respectively. In contrast, DNCB, a well known sensitizer, was positive after 24, 48 and 72 hours.

It can be concluded that test substance was not a sensitizer.

Conclusion

Less than ≥ 30 % of exposed population, showed positive reactions at intradermal induction dose higher than 1 %.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

60 guinea pigs were divided in three groups, 20 animals each group: one group was treated with test item; another with 1-chloro-2,4-dinitrobenzene (DNCB) as a positive control and the third group served as negative controls, treated with water and Freuds Adjuvant alone. Test substance was dissolved with water or Adjuvant respectively to 5 % solution, which was used for the paired injection on day 1 of the study. The test was started with three intradermal paired injections; on day 8, a patch (25 cm2) soaked with 3 ml was fixed for 48 hours on the clipped backs. 21 days after the start, the flanks of the animals were clipped and on the next day a patch was fixed for 24 hours, using test item 3 ml of the 5 % solution for the treated and negative control animals.

After 24 or 48 hours respectively, the patches were removed and the resulting reactions were evaluated.

The test item administered to guinea pigs, according to the maximization test, resulted in no reaction after 24, 48 and 72 hours respectively. In contrast, DNCB, a well known sensitizer, was positive after 24, 48 and 72 hours. It can be concluded that test substance was not a sensitizer.

Since the Acid Yellow 235 lot tested in the key study was characterized by an appreciable non-hazardous impurity content, the available data on structural analogous Similar Substance 01 has been taken into account, in order to confirm the study outcomes. The read across approach can be considered as reliable and adequate for the purpose; details and explanations are detailed in the report attached to the IUCLID section 13.2.

The study was performed to detect the sensitisation potential of the Similar Substance 01 in the guinea pig maximisation test, by following the OECD Guideline No. 406. During induction phase on day 0 test substance was delivered by intradermal injections, with test item at 5 %. On day 8 of epidermal induction was performed with 50 % of test item in physiological saline, under occlusive conditions. During the challenge phase the test substance was administrated at 30 % in physiological saline.

No animal of the test group was sensitised by the substance under the experimental condition employed.

Justification for classification or non-classification

According to the CLP Regulation (EC) No 1272/2008, 3.4 Respiratory or skin sensitisation section, skin sensitizer means a substance that will lead to an allergic response following skin contact.

Based on the Guinea Pig Maximisation Test (GPMT) results, a substance is considered a skin sensitizer when: equal or more than 30 % to 60 % responding at intradermal induction dose > 0.1 % to ≤ 1 %; or equal or more than 30 % responding at intradermal induction dose higher than 1 %.

Less than ≥ 30 % of exposed population showed positive reactions at intradermal induction dose higher than 1 %.

In conclusion, Acid Yellow 235 does not meet the criteria to be classified as skin sensitizer, according to the CLP Regulation (EC) No 1272/2008.