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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:
2010-01-19 to 2010-04-16
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
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
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): CAE
- Substance type: UVCB
- Physical state: oily semi-liquid orange-couloured to brown
- Purity test date: 12/01/2010
- Lot/batch No.: 1541
- Expiration date of the lot/batch: 27 November 2010
- Storage condition of test material: In an airtight container, under nitrogen, protected from the light and from the heat

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Breeder Janvier
- Age at study initiation: 9 weeks
- Weight at study initiation: 20.4 ± 1.1 g
- Housing: individual, crystal polystyrene cages
- Diet (e.g. ad libitum): "SSNIFF R/M-H pelleted maintenance diet", ad lib
- Water (e.g. ad libitum): drinking water filtered using a 0.22 micron meter filter, ad lib
- Acclimation period: 5 days at least


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 4 March 2009 To: 02 April 2009

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
25, 10, 5, 2.5, 1 and 0 % (v/v)
No. of animals per dose:
4 (at all doses)
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: appropriate solution in AOO vehicle
- Irritation: a range-finding test performed on mice at the concentrations of 10, 25, 50 and 100%

MAIN STUDIES
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: SI ≥ 3

TREATMENT PREPARATION AND ADMINISTRATION:
in the vehicle, at 25 µL on both ears
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:
The positive control results were valid: the conditions of the test allow the identification of positive dermal sensitisers.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: see Table 1
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: see Table 1

Any other information on results incl. tables

Table 1:

Concentration
(% v/v in vehicle) 
dpm per node SI  Increase in ear thickness (% between day 1 and day 6)  Interpretation of irritancy 
Vehicle AOO  45.83 - 3.13 -
Test item 1%  45.06 0.98 4.04 Non irritant 
Test item 2.5%  42.75 0.93 6.38 Non irritant
Test item 5%  36.00 0.79 4.12 Non irritant
Test item 10% 74.26 1.62 9.38 Non irritant
Test item 25% 475.96 10.39 20.41 Slightly irritant
HCA 25% 317.92 - - -

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information See in Attached background material "Statement CAE JFN 24th July 2011.pdf" Criteria used for interpretation of results: expert judgment
Conclusions:
Preliminary experiments showed that CAE concentrations > 25% induced a skin irritation at day 6. Thus, the 25% concentration was retained for highest tested concentration for the LLNA. Conclusion was that CAE should be considered as a weak sensitizer since the EC3 value was equal to 12%.
Of note, the 25% CAE concentration was not totally devoid of irritant properties as reported by study director:
i) clinical observation showed dryness of the 25% C CAE-treated ears in all animals (4/4) and erythema in ¼ animals (page 7 and 20/33);
ii) a 20 to 30% ear thickness increase was noted at day 6 in all 25% CAE-treated animals (page 17/33-preliminary exp. and page 22/33 pivotal exp.). Therefore, we interpret the results of the LLNA as false positives because of the use of a “border-line” irritant concentration of CAE.
If the LLNA had been conducted with the non-irritant 10% concentration, it would have been negative.
Executive summary:

According to the study director, the test item should be considered as a weak sensitizer based on the EC3 of 12%.

According to the expert judgment, there are 4 types of arguments for not taking into account the positive CAE LLNA:

i) LLNA is not validated for UVCB;

ii) positive LLNA is not synonymous of skin sensitization properties;

iii) there are strong arguments to consider the positive LLNA as false-positive through an irritant effect of CAE and the vehicle;

iv) there is no bibliographic and epidemiological data on CAE-induced allergy.

Please see the document "Statement CAE JFN 24th July 2011.pdf" for more details.

Based on these arguments, CAE is non-classified as skin sensitiser.