Manganese, 4-[(5-chloro-4-methyl-2-sulfophenyl)azo]-3-hydroxy-2-naphthalenecarboxylic acid complex

Endpoint summary

Description of key information

Pigment Red 48:4(Mn) did not cause skin sensitization in the LLNA. The study followed OECD testing guideline 429 (2002) and the principles of GLP, and the choice of doses is adequately justified.

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:

2012

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:

- Name of test material (as cited in study report): DCC Red 2792
- Composition: no details
- Lot/batch No.: #5119-T4
- Analytical purity: > 90 % Pigment Red 48:4
- Expiration date of the lot/batch:September 2022
- Stability under test conditions: stable
- Storage condition of test material: room temperature

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Netherlands
- Age at study initiation: 9 - 10 weeks
- Housing: single caging
- Diet (e.g. ad libitum): pelleted standard diet, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 + 3°C
- Humidity (%): 45-65%
- Photoperiod (hrs dark / hrs light): 12h/12h

Vehicle:

dimethyl sulphoxide

Concentration:

2.5, 5, and 10 %

No. of animals per dose:

5

Details on study design:

A solubility experiment was performed according to the recommendations given by OECD 429. The highest test item concentration, which could be technically used was a 25% suspension in dimethylsulfoxide. At a concentration of 20% and below, the test item could be dissolved in the vehicle. At higher concentrations, an applicable formulation of the test item was not achieved, neither by the use of other vehicles nor by using additional methods to formulate the test item (e.g. vortexing, sonicating, warming to 37°C).

To determine the highest non-irritant test concentration that did at the same time not induce signs of systemic toxicity, a pre-test was performed in two animals and stated in raw data and report. Two mice were treated by (epidermal) topical application to the dorsal surface of each ear with test item concentrations of 10 and 25% once daily each on three consecutive days.The animal treated with the high dose of the test item showed an increase in ear thickness of 51% on day 6 of the study, compared to pre-treatment value. The increase in ear thickness in the animal treated with the low dose was below the threshold of 25% (i.e., 18.4% increase compared to pre-treatment value). Ear weights were increased by 13.2 and 25.1%, respectively, for the low and high dose, compared to historical vehicle values obtained for dimethylsulfoxide (27.9 mg). Erythema of the ear skin could not be determined, due to the colour of test item. Thus, the test item in the main study was assayed at 2.5, 5, and 10% (w/w). The highest concentration tested was the highest level that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation in the pre-experiment.

Positive control substance(s):

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

Statistics:

The mean values and standard deviations were calculated in the body weight tables and for the DPM values (group mean DPM ± standard deviation). The Dean-Dixon-Test and the Grubb’s test were used for identification of possible outliers (performed with Microsoft Excel 2003). Three outlier animals (animal 7, 11 and 18) were identified and excluded from calculations of group mean dpm, SD and Stimulation Index. However, these outliers had no influence on the overall result of the study. Both biological and statistical significance were considered together.

Positive control results:

Performed in April 2012: 25% in acetone/olive oil (4+1) gave an SI of 3.7.

Parameter:

SI

Value:

0.9

Test group / Remarks:

10%

Parameter:

SI

Value:

0.7

Test group / Remarks:

5%

Parameter:

SI

Value:

1

Test group / Remarks:

2.5%

Parameter:

SI

Value:

1

Test group / Remarks:

Vehicle control

The animals did not show any signs of systemic toxicity or local skin irritation during the course of the study and no cases of mortality were observed. Erythema of the ear skin could not be determined, due to the colour of test item. The body weights of the animals, recorded prior to the 1st application and prior to necropsy were within the range commonly recorded for animals of this strain and age.

DISINTEGRATIONS PER MINUTE

DPM minus background control: 1024.0 (10%) 801.8 (5%) 1156.8 (2.5%) 1182.1 (vehicle control)

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Pigment Red 48:4 formulated in dimethylsulfoxide was assessed for its possible skin sensitising potential (Harlan 2012). For this purpose a local lymph node assay was performed using test item concentrations of 2.5, 5, and 10% (w/w). The highest concentration tested was the highest concentration that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation as confirmed by a pre-experiment. The animals did not show any signs of systemic toxicity or local skin irritation during the course of the study and no cases of mortality were observed. Erythema of the ear skin could not be determined, due to the colour of test item. In this study Stimulation Indices (S.I.) of 1.0, 0.7 and 0.9 were determined with the test item at concentrations of 2.5, 5, and 10% (w/w) in dimethylsulfoxide, respectively. In each of the groups treated with different concentrations of the test item, an outlier was identified and excluded from the calculation of group mean dpm, SD and Stimulation Index. However, these three outliers were not biologically relevant and had no influence on the

overall outcome of the study. The studied followed OECD testing guideline 429 and the principles of GLP.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

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 according to Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008.