N,N'-(2-chloro-1,4-phenylene)bis[4-[(2,5-dichlorophenyl)azo]-3-hydroxynaphthalene-2-carboxamide]

Endpoint summary

Description of key information

Non skin sensitizing (OECD 429, GLP)

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

- Substance type: red solid
- Physical state: solid
- Analytical purity: 99.6%
- Purity test date: 1.12.2006
- Expiration date of the lot/batch: March 10, 1990
- Stability under test conditions: stable
- Storage condition of test material: at room temperature

Species:

mouse

Strain:

CBA

Sex:

female

Vehicle:

dimethylformamide

Concentration:

2.5, 5, and 10%

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
a pretest was performed in two mice on three consecutive days.
- Compound solubility: The data showed that the highest test item concentration, which could be technically used was a 10% solution. Higher concentrations could not be achieved with other vehicles (e.g. acetone:olive oil, methyl ethyl ketone, propylene glycol, DMSO, or ethanol:water).
- Irritation: Irritation of the ear skin could not be observed, due to the colour of the test item.


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: 3fold increase of S.I.

TREATMENT PREPARATION AND ADMINISTRATION: Each test group of mice was treated by topical (epidermal) application to the dorsal
surface of each ear lobe (left and right) with different test item concentrations of 2.5, 5, and 10% (w/v) in dimethylformamide. The application volume, 25 µl, was spread over the entire dorsal surface ( 8 mm) of each ear lobe once daily for three consecutive days. A further group of mice was treated with an equivalent volume of the relevant vehicle alone (control animals).

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Positive control results:

EC3 = 6.7%

Parameter:

SI

Remarks on result:

other: 1.53, 1.43, and 2.37

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Control: 5703 2.5%: 8735 5%: 8128 10%: 13466

No deaths occurred during the study period.

No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period. Due to the colour of the test item iritation of the ear skin could bot be observed at the mid and high dose.

The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age.

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Pigment Red 144 was tested in two Local Lymph Node assays according to GLP (RCC 2007, Synthesia 2009). The study by RCC followed OECD testing guideline 429 without deviations. The study by Synthesia was performed with the non-radioactive version which uses lymph node cell count as the indicator. Animals exposed to test substance showed no pathological skin reactions and no other negative clinical symptoms of intoxication throughout the experiment. There was no significant difference in body weight increment of all groups in comparison to the vehicle control. There were no clinical observations attributable to the treatment with test substance. The test substance showed a tendency to increase ear weight at the highest dose level but not paired with lymph node hyperplasia. Residues of the test substance on the ears caused this increased weight.

 

The study at RCC resulted in simulation indeces of 1.53, 1.43, and 2.37 at concentrations of 2.5, 5, and 10% in dimethylformamide. A pre-test showed that DMF was the best suited solvent and that higher concentrations could not be achieved. No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period. Due to the colour of the test item iritation of the ear skin could both be observed at the mid and high dose. The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age. Pigment Red 144 is therefore non sensitizing on 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. As a result the substance is not considered to be classified for skin sensitization under Regulation (EC) No. 1272/2008..