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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From week 20 to week 23 of 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study with no significant deviations or restrictions. Only relative humidity in the cages was slightly higher than in the OECD guideline requirements.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymphnode assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): α, α, α, trichlorotoluene
- Physical state: clear colourless liquid
- Analytical purity: 99.211 %
- Lot/batch No.: 040930505
- Expiration date of the lot/batch: 28 April 2011 (allocated by NOTOX, 1 year after receipt of the test substance)
- Stability under test conditions:
Stability in vehicle:
• Acetone: Unknown
• Olive oil: Unknown
Solubility in vehicle:
• Acetone: Not indicated
• Olive oil: Not indicated
- Storage condition of test material: At room temperature in the dark

No further infiormation

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan, Horst, The Netherlands.
- Age at study initiation: Young adult animals (approx. 11 weeks old)
- Housing: Animals were housed in a controlled environment individually in Macrolon cages
- Diet (e.g. ad libitum): Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany)
- Water (e.g. ad libitum): Free access to tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): a temperature of 21.0 ± 3.0ºC (actual range: 20.4 – 23.3ºC)
- Humidity (%): a relative humidity of 40-70% (actual range: 42 – 72%)
- Air changes (per hr): 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours darkness per day.

No further information

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
Group animal numbers induction (test substance; % w/w)

1 01 - 05 0 (Acetone/Olive oil (4:1 v/v))
2 06 - 10 5
3 11 - 15 10
4 16 - 20 25

No. of animals per dose:
Five animals per dose
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: The vehicle was selected based on trial formulations performed at NOTOX and on test substance data supplied by the sponsor.The test substance formulations (w/w) were prepared within 4 hours prior to each treatment. No adjustment was made for specific gravity of the vehicle. Homogeneity was obtained to visually acceptable levels
- Irritation: A preliminary irritation study was conducted in order to select the highest test substance concentration to be used in the main study. In principle, this concentration should be well tolerated systemically by the animals and may give moderate irritation (maximally grade 2at the highest concentration.

Initially, two test substance concentrations were tested; a 100% and 50% concentration. The highest concentration was the maximum concentration as required in the test guidelines (undiluted for liquids, 50% for solids).
The test system, procedures and techniques were identical to those used during Days 1 to 3 of the main study unless otherwise specified. Two young adult animals were selected (8-14 weeks old). Each animal was treated with one concentration on three consecutive days. Approximately 3-4 hours after the last exposure, the irritation of the ears was assessed. Bodyweights were determined on Day 3. The animals were sacrificed after the final observation and no necropsy was performed.

Based on the results of the initially treated animals, three additional animals were treated in a similar manner with three lower concentrations (5%, 10% and 25%) at a later stage

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: OECD 429
- 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, based on the test guideline and recommendations done by ICCVAM

No further infiormation
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
No thorough statistics needed

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: The SI values calculated for the substance concentrations 5, 10 and 25% were 16.1, 17.7 and 28.2 respectively.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Mean DPM/animal values for the experimental groups treated with test substance concentrations 5, 10 and 25% were 18899, 20663 and 33053 respectively.The mean DPM/animal value for the vehicle control group was 1170.

Any other information on results incl. tables

The animals tested at 50 and 100% both showed hunched posture, piloerection, uncoordinated movements, lethargy and ptosis on Day 2. These animals were sacrificed for ethical reasons on Day 2. 

Three additional animals were tested at 5, 10 and 25%, respectively. Slight erythema was noted for the animals at 10 and 25%, without any accompanying signs of systemic toxicity. Based on these results, the highest test substance concentration selected for the main study was a 25% concentration. Slight erythema was seen for all animals at 25 and 10% and for 3 animals at 5%. No oedema was observed in any of the animals examined.

All auricular lymph nodes of the animals of the experimental groups were considered to be larger in size. One control animal also had lymph nodes that were considered to be larger in size.

All nodes of the experimental groups were larger in size, and the largest nodes were found in the highest dose groups.

No macroscopic abnormalities of the surrounding area were noted. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period. No mortality occurred and no symptoms of systemic toxicity were observed in the animals of the main study.

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information CLP and DSD criteria
Conclusions:
According to the authors, these results show that the test substance elicits a stimulation index (SI) higher than 3. The EC3 value (the estimated test substance concentration that will give a SI =3) was not determined. Thus, based on these results, according to the recommendations made in the test guidelines and according to the criteria laid down in Regulation (EC) No 1272/2008 and in the DSD regulation (EEC) No 67/548, α, α, α, trichlorotoluene would be regarded as skin sensitizer.
Executive summary:

The authors of this study report conducted the assessment of Contact Hypersensitivity to α, α, α, trichlorotoluene in the Mouse (Local Lymph Node Assay). The study was carried out according to the OECD guideline n° 429 with no observed deviations or restrictions.

The test substance concentrations were selected for the main study were based on the results of a preliminary study.

In the main study, three experimental groups of five female/J mice were treated with test substance concentrations of 5, 10 or 25% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Acetone/Olive oil (4:1 v/v)).

Three days after the last exposure, all animals were injected with3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal.

After precipitating theof the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group.

 

No oedema was observed in any of the animals examined.

 

All auricular lymph nodes of the animals of the experimental groups were considered to be larger in size. One control animal also had lymph nodes that were considered to be larger in size. No macroscopic abnormalities of the surrounding area were noted in any of the animals.

 

Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

 

Mean DPM/animal values for the experimental groups treated with test substance concentrations 5, 10 and 25% were 18899, 20663 and 33053 respectively.

The mean DPM/animal value for the vehicle control group was 1170.

 

The SI values calculated for the substance concentrations 5, 10 and 25% were 16.1, 17.7 and 28.2 respectively. These results show that the test substance elicits an SI3. The EC3 value (the estimated test substance concentration that will give a SI =3) was not determined.

 

The six-month reliability check with α-hexylcinnamicaldehyde indicates that the Local Lymph Node Assay as performed at NOTOX is an appropriate and valid model for testing for contact hypersensitivity.

Based on these results, according to the Regulation (EC) No 1272/2008 on classification, labeling and packaging of substances and mixtures and the DSD regulation (EEC) No 67/548, α, α, α, trichlorotoluene should be classified as skin sensitizer (Category 1) and labeled as H317: May cause an allergic skin reaction or R 43: May cause sensitisation by skin contact according to the DSD directive.