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Description of key information

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:
2007-01-03 to 2007-01-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline study
Qualifier:
according to
Guideline:
OECD Guideline 429 (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 lymph node assay (LLNA)
Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Jackson Laboratories
- Age at study initiation: approx. 2 month
- Weight at study initiation: 15.4 - 21.4 grams
- Housing: Animals were housed 1 per cage in suspended wire cages. Bedding was placed beneath the cages and changed at least three times/week.
- Diet: Ad libitum-Fresh PMI Rodent Chow (Diet #5001)
- Water: Ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Temperature was controlled
- Photoperiod: 12 hr cycle
Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
25 %, 50 %, 100 %
No. of animals per dose:
5 females
Details on study design:
RANGE FINDING TESTS:
Three groups of two animals per group (a total of six) were treated with three concentrations (25%, 50% and 100%) in the vehicle for three consecutive days. The ears were observed for edema and/or erythema and ear measurements were taken on Day 1, Day 3 (at approximately 48 hours), and Day 6 (end of in-life phase). On Day 6, the mice were sacrificed using CO2 asphyxiation. Ear thickness (ET) changes on Day 3 and Day 6 were expressed as a percent of the Day 1 pre-study values. An increase of 25% or more in ET was considered biologically significant (based on historical laboratory data) and indicative of a primary dermal irritation response.
The test article concentrations used in the definitive LLNA study were chosen such that:
1) maximum concentration tested was the highest achievable solution of the test article in the vehicle, while
2) avoiding both overt systemic toxicity and excessive local irritation.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
Groups of five mice were treated by topical application of the test article concentrations, vehicle or positive control to the dorsum of each ear once daily for three consecutive days (at approximately the same time each day). The test article mixture, control or vehicle was spread over the entire dorsal surface of the ear using a micropipette at 25 uL/ear.

Lymph nodes were isolated from every individual animal and lymphocyte proliferation and SI were measured and calcuated for every single animal.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Positive control results:
The stimulation index of the positive control was 9.1 (+/- 3.5)
Parameter:
SI
Remarks on result:
other: 25 % test item: 1.8 (+/- 0.9) 50 % test item: 1.5 (+/- 0.8) 100 % test item: 2.4 (+/- 1.2)

Test articel formulation and dosing:

The test article formed a homogenous mixture in the verhicle, AOO. No difficulties were experienced with the application of the test article to the ears or with the retention of test article by the ear surface.

Body weights:

Body weight changes were normal.

Mortality and systemic observations:

All animals survived the in-life phase of the study and appeared normal.

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

For the assessment of the skin sensitising potential of the test item a Local Lymph Node Assay was performed with CBA mice according to OECD 429 (GLP guideline study; MB Research Laboratories 2007). Topical application of the test item at 25% and 50% resulted in stimulation indices of less than 3 compared to the vehicle control group. Topical application of the test item at 100% resulted in a stimulation index of less than 3 compared to the naive control group. Therefore, the test item is not a dermal sensitizer in the Local Lymph Node Assay.


Migrated from Short description of key information:
The test item is not sensitising.

Justification for selection of skin sensitisation endpoint:
The Key study was selected (GLP and Guideline study).

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Classification is not warranted according to the criteria of EU Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No 1272/2008.