2-hydroxycyclohepta-2,4,6-trienone

Skin sensitisation

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 guideline

Test guideline 1

Qualifier:

according to guideline

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

Test guideline 2

Qualifier:

equivalent or similar to guideline

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 lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxycyclohepta-2,4,6-trienone

EC Number:

208-577-2

EC Name:

2-hydroxycyclohepta-2,4,6-trienone

Cas Number:

533-75-5

Molecular formula:

C7H6O2

IUPAC Name:

2-hydroxycyclohepta-2,4,6-trien-1-one

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)

Results

Results 1

Key result

Parameter:

SI

Value:

1

Test group / Remarks:

0.5%

Results 2

Key result

Parameter:

SI

Value:

3.3

Test group / Remarks:

5.0%

Results 3

Key result

Parameter:

SI

Value:

5.2

Test group / Remarks:

10%

Results 4

Key result

Parameter:

SI

Test group / Remarks:

20%

Remarks on result:

not determinable

Results 5

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.