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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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Remarks:
limited data only, no information on positive control / reliability check

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
adopted: 24 April 2002
Deviations:
yes
Remarks:
limited documentation, no information on positive control / reliability check
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
adopted: 22 Jul 2010
Deviations:
yes
Remarks:
limited documentation, no information on positive control / reliability check
GLP compliance:
yes
Type of study:
mouse local lymphnode assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation:
7 - 12 weeks

Study design: in vivo (LLNA)

Vehicle:
dimethylformamide
Concentration:
0.5, 5.0, 10.0, 20.0%
No. of animals per dose:
not specified
Details on study design:
MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method:
Local Lymph Node Assay
- Criteria used to consider a positive response:
A substance was classified as a skin sensitizer if it induced a threefold or greater increase in local lymph node proliferative activity at one or more test concentrations when compared with concurrent vehicle-treated controls (SI ≥ 3). When the LLNA dose-response curve included concentrations that induced at least one SI greater than 3 and one SI less than 3, EC3 values were calculated by linear interpolation. The EC3 value was used to classify the relative skin sensitisation potency as follows:
EC3 Value (%) ≥ 10 to ≤ 100 -> Weak
EC3 Value (%) ≥ 1 to ≤ 10 -> Moderate
EC3 Value (%) ≥ 0.1 to ≤ 1 -> Strong
EC3 Value (%) < 0.1 -> Extreme

TREATMENT PREPARATION AND ADMINISTRATION:
Animals were exposed topically on the dorsum of both ears to 25 µL of test material or to an equal volume of vehicle alone. Treatment was performed daily for 3 consecutive days. Five days after the initiation of exposure, all mice were injected via the tail vein with 250 µL of phosphate buffered saline (PBS) containing 20 µCi of tritiated thymidine. Mice were sacrificed 5 hours later, and the draining auricular lymph nodes were excised and pooled for each experimental group or each individual animal. The incorporation of tritiated thymidine measured by beta scintillation counting was reported in disintegrations per minute (dpm). A stimulation index (SI) was calculated for each chemical-treated group as the ratio of the dpm of the treated group (or mean dpm when individual animals were assessed) to the dpm or mean dpm of the concurrent vehicle control group.
Positive control substance(s):
not specified

Results and discussion

Positive control results:
not specified

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
1
Test group / Remarks:
0.5%
Key result
Parameter:
SI
Value:
3.3
Test group / Remarks:
5.0%
Key result
Parameter:
SI
Value:
5.2
Test group / Remarks:
10%
Key result
Parameter:
SI
Test group / Remarks:
20%
Remarks on result:
not determinable
Key result
Parameter:
EC3
Value:
4.3

Applicant's summary and conclusion

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
Under the conditions of the local lymph node assay, the test substance revealed an SI > 3 at 5% and 10% in dimethylformamide. Consequently, the EC3 was calculated to be 4.3%. Therefore, the test substance is considered to be a weak sensitiser.