Formaldehyde, reaction products with m-phenylenediamine, sodium sulfide (Na2S) and sulfur

Endpoint summary

Description of key information

In a local lymph node assay (LLNA) according to OECD 429, the test item was not sensitising to skin.

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:

01 to 20 August 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

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/J

Sex:

female

Details on test animals and environmental conditions:

- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: Young adult animals (approx. 10 weeks old)
- Weight at study initiation: Body weight variation was within +/- 20% of the sex mean.
- Housing: Animals were group housed in labeld makrolon cages.
- Diet: Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water: Free access to tap water.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, approximately 15 room air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study. Deviations from the maximum level of daily mean relative humidity occurred. Laboratory historical data do not indicate an effect of the deviations.

IN-LIFE DATES: From: 01 - 21 August 2012

Vehicle:

dimethylformamide

Concentration:

0, 25, 50, 100%

No. of animals per dose:

5

Details on study design:

The vehicle was selected based on trial formulations performed at WIL Research Europe and on test substance data supplied by the sponsor.

RANGE FINDING TESTS:
In the interest of animal welfare and to minimize any testing likely to produce severe responses in animals, a weight of evidence analysis was performed prior to start of this study. All available information was evaluated (e.g. existing human and animal data, literature, substance data supplied by the sponsor, analysis of structure activity relationships (SAR), physicochemical properties and reactivity (pH, buffering capacity).

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response:DPM values are presented for each animal and for each dose group. A Stimulation Index (SI) is calculated for each group. The SI is the ratio of the DPM/group compared to DPM/vehicle control group. If the results indicate a SI ≥ 3, the test substance may be regarded as a skin sensitizer. The results were evaluated according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (20011) and the Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on Classification, Labelling and Packaging of substances and mixtures.

ANIMAL ASSIGNMENT
Three groups of five animals were treated with one test substance concentration per group. One group of five animals was treated with vehicle.

TREATMENT PREPARATION AND ADMINISTRATION:
Test substance preparation: The test substance formulations (w/w) were prepared within 4 hours prior to each treatment. Homogeneity was obtained to visually acceptable levels.
Rationale for vehicle: The vehicle was selected based on trial formulations performed at WIL Research Europe and on test substance data supplied by the sponsor.

Induction - Days 1, 2 and 3; Excision of nodes - Day 6; Tissue processing for radioacitivity - Day 6; Radioactivity measurements - Day 7; Performed according to test guidelines.

Observations:
Mortality/Viability: Twice daily.
Body weights: On Day 1 (pre-dose) and Day 6 (prior to necropsy).
Clinical signs: Once daily on Days 1-6 (on Days 1-3 between 3 and 4 hours after dosing).
Irritation: Once daily on Days 1-6 (on Days 1 - 3 immediately after dosing) according to the following numerical scoring system. Furthermore, a description of all other (local) effects was recorded according to guidelines.

Positive control substance(s):

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

Statistics:

Not performed.

Positive control results:

The six-month reliability check with Alpha-hexylcinnamicaldehyde indicates that the Local Lymph Node Assay as performed at WIL Research Europe is an appropriate model for testing for contact hypersensitivity. See attached document 'Reliability check'.

Key result

Parameter:

SI

Value:

1.9

Test group / Remarks:

test substance concentration: 25%

Key result

Parameter:

SI

Value:

1.5

Test group / Remarks:

test substance concentration: 50%

Key result

Parameter:

SI

Value:

1.4

Test group / Remarks:

test substance concentration: 100%

Key result

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean DPM/animal values for the experimental groups treated with test substance concentrations 25, 50 and 100% were 622, 510 and 478 DPM respectively. The mean DPM/animal value for the vehicle control group was 334 DPM.

Results Pre-screen test:

No irritation and no signs of systemic toxicity were observed in any of the animals examined. Based on these results, the highest test substance concentration selected for the main study was a 100% concentration.

 

Other results - main study:

 

Skin reactions / Irritation:

Black staining by the test substance prevented scoring for erythema after dosing on Days 1, 2 and 3 for all animals at 25%, 50% and 100%. No irritation of the ears was observed in any of the animals examined on Days 4, 5 and 6. 

 

Systemic toxicity/Body weights:

No mortality occurred and no clinical signs of systemic toxicity were observed in the animals of the main study. The body weight loss noted for some animals across the dose groups was considered not toxicologically significant since the changes were slight in nature and no concentration-related incidence was apparent.

 

Macroscopy of the auricular lymph nodes and surrounding area:

All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted in any of the animals.

Interpretation of results:

GHS criteria not met

Conclusions:

The SI values calculated for the substance concentrations 25, 50 and 100% were 1.9, 1.5 and 1.4 respectively.

Based on these results, C.I. Leuco Sulphur Brown 37 would not be regarded as a skin sensitizer according to the recommendations made in the test guidelines.

Executive summary:

In a local lymph node assay (LLNA), three experimental groups of five female CBA/J mice were treated with test substance concentrations of 25, 50 or 100% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Dimethyl formamide). All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted in any of the animals.
Mean DPM/animal values for the experimental groups treated with test substance concentrations 25, 50 and 100% were 622, 510 and 478 DPM respectively. The mean DPM/animal value for the vehicle control group was 334 DPM.
The SI values calculated for the substance concentrations 25, 50 and 100% were 1.9, 1.5 and 1.4 respectively. Since there was no indication that the test substance elicited an SI ≥ 3 when tested up to 100%, the test material was considered to be no skin sensitizer.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitization: in vivo (LLNA)

In a local lymph node assay (LLNA) according to OECD 429, three experimental groups of five female CBA/J mice were treated with test substance concentrations of 25, 50 or 100% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Dimethyl formamide). All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted in any of the animals.
Mean DPM/animal values for the experimental groups treated with test substance concentrations 25, 50 and 100% were 622, 510 and 478 DPM respectively. The mean DPM/animal value for the vehicle control group was 334 DPM.
The SI values calculated for the substance concentrations 25, 50 and 100% were 1.9, 1.5 and 1.4 respectively. Since there was no indication that the test substance elicited an SI ≥ 3 when tested up to 100%, the test material was considered to be no skin sensitizer.

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 is reliable and suitable for classification purposes under Regulation (EC) No 1272/2008.

 

Based on available data on skin sensitisation, the test item is not classified according to Regulation (EC) No 1272/2008 (CLP), as amended for the eighteenth time in Regulation (EU) 2022/692.