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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:
2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted in compliance with OECD GLP (1997) regulations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report Date:
2014

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
yes
Remarks:
Deviations from the maximum daily mean relative humidity occurred. Lab historical data do not indicate an effect of the deviations.
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: Liquid
Details on test material:
- Name of test material (as cited in study report): MTDID 16437
- Substance type: Mono constituent
- Physical state: Liquid
- Analytical purity: 98.5%
- Purity test date: 04/08/2014
- Lot/batch No.: 114B1005
- Expiration date of the lot/batch: No data
- Stability under test conditions: No data
- Storage condition of test material: At room temperature in the dark under nitrogen

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/J
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: Approximately 10 weeks old
- Weight at study initiation: 19-23 grams
- Housing: Group housed in labeled Makrolon cages (MIII type; height 18 cm) containing sterilized sawdust as bedding. Paper and shelters were supplied as cage enrichment.
- Diet (e.g. ad libitum): Pelleted rodent diet (SM R/M-Z from SSNIFF Spezialdiaten GmbH, Soest, Germany) ad libitum.
- Water (e.g. ad libitum): Tap water, ad libitum.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-24
- Humidity (%): 40-70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 09 July 2014 To: 28 July 2014

Study design: in vivo (LLNA)

Vehicle:
methyl ethyl ketone
Concentration:
0 (control), 10, 30, or 100% w/w test article in methyl ethyl ketone.
No. of animals per dose:
5
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: Soluble in vehicle
- Irritation: No irritation observed (variations in ear thickness during the observation period were less than 25% from Day 1 pre-dose values).
- Lymph node proliferation response: Not performed in the pre-screen.

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 each dose group. A Stimulation Index (SI) is calculated from each group using the individual SI values. The individual SI is the ratio of the DPM/animal compared to the DPM/vehicle control group. If the results indicated a SI greater than or equal to 3, the test substance may be regarded as a skin sensitizer. Consideration was given to the EC3 value (the estimated test substance concentration that will give a SI=3).

TREATMENT PREPARATION AND ADMINISTRATION: The dorsal surface of both ears of each mouse was topically treated (25 uL/ear) with the test substance concentration, at approximately the same time each day from study Days 1 through 3. The control animals were treated in the same way as the experimental animals with the vehicle alone.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:
A positive control reliability check with Alpha-hexylcinnamaldehyde is conducted every six months.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: The SI values calculated for the subtance concentrations 10, 30 and 100% were 1.4, 1.5 and 1.5, respectively.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 30 and 100% were 351, 395 and 396 DPM, respectively. The mean DPM/animal value for the vehicle control group was 258 DPM.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Based on the results of the study, the test article did not show evidence of dermal sensitization potential.
Executive summary:

The dermal sensitization potential of the test article (Clear colorless liquid, purity 98.5%, Batch 114B1005) was evaluated in the local lymph node assay (LLNA) with female CBA/J strain mice. The study was performed in compliance with OECD GLP ENV/MC/CHEM (98) 17 (revised 1997). The test method was based on OECD No. 429 (2010). The test article was prepared in methyl ethyl ketone. A pre-screen test was conducted to select test article concentrations of 10%, 30% and 100%. Female mice (4/treatment) received the negative control (methyl ethyl ketone), 10%, 30%, or 100% concentrations of the test substance. The corresponding treatment (25 uL/ear) was applied to the dorsal surface of both ears for three consecutive days. Three days after the last exposure (Day 6), all animals were injected with 0.25 mL sterile phosphate buffered saline containing 3 H-methyl thymidine and subsequently euthanized. The nodes were pooled for each animal, and lymphocyte proliferation was determined by measuring disintegrations per minute (DPM). The stimulation index (SI) was calculated for each group. Observations for mortality (once daily), body weights (Day 1 and Day 6), clinical signs (once daily), ear thickness (Days 1-3, and Day 6), and irritation (Days 1-3 and 6) were performed as well. A six-month reliability check with Alpha-hexyl cinnamaldehyde is performed to ensure that the model is appropriate for testing contact hypersensitivity. Mean DPM/node values for the 10%, 30%, and 100% test article concentrations were 351, 395, and 396 DPM respectively. The negative control mean DPM/node value was 258 DPM. The SI values for test concentrations of 10%, 30%, and 100% were 1.4, 1.5, and 1.5 respectively. No EC3 value was calculated because all SI values were < 3. The positive control SI was >3 so the test method was considered valid. No irritation of the ears was observed in any animal. No mortality, clinical signs of toxicity, or significant body weight changes were observed. Based on the results of the study, the test article did not show evidence of dermal sensitization potential.