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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted under GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

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
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): MTDID 7145
- Substance type: Clear colorless liquid
- Physical state: liquid
- Analytical purity: ~94.5%
- Lot/batch no.: Batch 142072:43
- Expiration date of the lot/batch: 30 December 2007
- Stability under test conditions: Stable (but test substance is volatile)
- Storage condition of test material: At room temperature in the dark
- Other: pH: 7.2. Specific gravity: 1.8

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA; inbred, SPH quality
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Frances, L'Arbresle Cedex, France
- Age at study initiation: 10-11 weeks
- Weight at study initiation: 19-26 g
- Housing: Individual housing in labeled Macrolon cages containing sterilized sawdust as bedding material
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.8-23.9 C
- Humidity (%): 38-77%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hrs dark/ 12hrs light

Study design: in vivo (LLNA)

Vehicle:
unchanged (no vehicle)
Concentration:
0% (control) and 100%(undiluted)
No. of animals per dose:
5
Details on study design:
RANGE FINDING TESTS:
- Irritation:No irritation was observed in the one animal tested.
- Lymph node proliferation response: not evaluated
MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method:Local Lymph Node Assay (LLNA)
- Criteria used to consider a positive response: a simulation index greater than or equal to 3 relative to the naive control group
TREATMENT PREPARATION AND ADMINISTRATION: The test article was administered undiluted by pipette to the dorsal surface of both ears (25microliters/ear) or animals in the 100% treatment group at approximiately the same time each day for three consecutive days.
Positive control substance(s):
other:
Statistics:
None

Results and discussion

Positive control results:
A concurrent positive control was not evaluated in this study. A reliability check on the test system was last performed in March 2007 using the positive control substance alpha-hexyl cinnamaldehyde (HCA). In this test, stimulation indicates for the positive control stubstance at 5%, 10% and 25% concentrations were 1.3, 1.5 and 5.5, respectivley, relative to the vehicle control (acetone/olive oil 4:1 v/v). The EC3 was 15.6%. The EC3 was in the acceptable range of 2% to 20%. EC3 values for HCA for the previous 4 reliability checks ranged from 7.3% to 13.1%

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
2.8
Variability:
See executive summary.
Test group / Remarks:
Mean
Remarks on result:
other: 100% Test Substance: 3.0 Control: 1.0 *In additionally treated animals: 100% Test Substance: 2.5 Control: 1.0
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: 100% Test Substance: 466 DPM Control: 154 DPM *In additionaly treated animals: 100% Test Substance: 312 DPM Control: 123 DPM

Any other information on results incl. tables

*In order to achieve more information regarding the SI=3 value, an additional group of animals was treated with 100% test substance concentration.

No irritation/skin reactions, mortality and systemic toxicity were observed in any of the animals examined. All nodes of all the animals were considered normal in size and body weights of the experimental animals remained in the same range.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Based on the results of this study, the test material is not a dermal sensitizer (SI=2.8) at concentrations up to 100%.
Executive summary:

The dermal sensitizing potential of the test article was evaluated in a local lymph node assay (LLNA) in female CBA/J mice following OECD Guideline 429 (effective April 2002). This concentration did not cause irritation in a preliminary irritation screen. In the definitive study, animals (5/group) were administered 25 µL of control (Milli-Q or Milli-U water) or 100% of the test article by topical application to the dorsum of each ear once daily for three consecutive days. Clinical observations were recorded daily. Body weights were recorded on days 1 and 6. Ear swelling measurements were recorded on days 1, 3 and 6. On day 6, the number of proliferating lymph node cells in the auricular lymph nodes were determined using a 3H-methyl thymidine method. The Stimulation Index (SI) was calculated and substances with a SI greater than or equal to 3 are considered to be potential sensitizers. DPM values for the first test article-treated group ranged from 176 -691 with the control values ranging from 83 -798. Due to the wide variability in responses in both test and control groups and to achieve more information regarding the SI value, the study was repeated with two additional groups. No skin reactions were observed in any animals. The DPM values in the second test article-treated group ranged from 69 -723 with the control values ranging from 67 -340. The calculated median SI was 2.8 when tested up to 100%. The positive control (hexylcinnamaldehyde) is tested once every 6 months at NOTOX and the most recent test indicated that the test method was valid. Based on the results of this study, the test article is not a dermal sensitizer (SI=2.8) at concentrations up to 100%.