Phenol, 4-(phenylamino)-, sulfurized, leuco deriv.

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 October - 19 November 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 3

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)

Test material

Test material information

Constituent 1

Reference substance name:

phenol, 4-(phenylamino)-, sulfurised, leuco deriv.

Molecular formula:

not applicable

IUPAC Name:

phenol, 4-(phenylamino)-, sulfurised, leuco deriv.

In vivo test system

Test animals

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. 9 weeks old)
- Weight at study initiation: Body weight variation was within +/- 20% of the sex mean (21 - 22 grams)
- 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.
Temporary deviations from the minimum level of daily mean relative humidity occurred.
IN-LIFE DATES: From: 31 October to 19 November 2012

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Concentration:

0, 10, 25 , 50%

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.

Necropsy: No necropsy was performed according to protocol.

Positive control substance(s):

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

Statistics:

Not performed.

Results and discussion

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'.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

0.7

Test group / Remarks:

test substance concentration: 10%

Results 2

Parameter:

SI

Value:

0.9

Test group / Remarks:

test substance concentration: 25%

Results 3

Key result

Parameter:

SI

Value:

0.5

Test group / Remarks:

test substance concentration: 50%

Results 4

Parameter:

other: disintegrations per minute (DPM)

Value:

513

Test group / Remarks:

test substance concentration: 10%

Results 5

Parameter:

other: disintegrations per minute (DPM)

Value:

616

Test group / Remarks:

test substance concentration: 25%

Results 6

Parameter:

other: disintegrations per minute (DPM)

Value:

384

Test group / Remarks:

test substance concentration 50%

Results 7

Parameter:

other: disintegrations per minute (DPM)

Value:

720

Test group / Remarks:

vehicle control group

Any other information on results incl. tables

Results Pre-screen test:

No irritation was observed in any of the animals examined. Variations in ear thickness during the observation period were less than 25% from Day 1 pre-dose values.

 

Black test substance remnants were present on the dorsal surface of the ears of both animals at 25% and 50% (Days 1-6). This did not hamper scoring of the skin reactions, except on Days 4 and 5 for both animals at 25% and one animal at 50%.

 

Dehydration and/or hunched posture noted for both animals at 25% on Days 4 and/or 5 was considered to have been caused by an obstructed nozzle of the water bottle as observed on Day 4. After clearing the nozzle on Day 4, these symptoms had resolved by Days 5/6.

 

Based on these results, the highest test substance concentration selected for the main study was a 50% concentration.

Other results - main study:

Skin reactions / Irritation:

No irritation of the ears was observed in any of the animals examined.

 

Black test substance remnants were present on the dorsal surface of the ears of all animals at 10% (Days 3 and 4) and at 25% and 50% (Days 1-6), which did not hamper scoring of the skin reactions.

Systemic toxicity/Body weights:

No mortality occurred and no clinical signs of systemic toxicity were observed in the animals of the main study. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

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.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In an LLNA study with mice, SI values calculated for the substance concentrations 10, 25 and 50% were 0.7, 0.9 and 0.5 respectively.
Since there was no indication that the test substance elicits an SI ≥ 3 when tested up to 50%, C.I. Leuco Sulphur Brown 96 was considered not to be a skin sensitizer. It was established that the EC3 value (the estimated test substance concentration that will give a SI =3) (if any) exceeds 50%.

Executive summary:

In the LLNA study, five animals each were treated with test substance concentrations of 0, 10, 25 and 50% in dimethylformamide by application of the substance formulation on both ears on three consecutive days. On day 6 all animals were injected with 3H-methyl thymidine and after 5 hours lymph nodes were excised and pooled for each group. The isolated DNA was subject to radioactivity measurements.

No irritation of the ears was observed in any of the animals examined. 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. The following SI values were calculated for 10, 25 and 50%, respectively: 0.7, 0.9 and 0.5.

Since there was no indication that the test substance elicits an SI ≥ 3 when tested up to 50%, C.I. Leuco Sulphur Brown 96 was considered not to be a skin sensitizer.