1,4:5,8-Dimethanonaphthalene, 2-ethylidene-1,2,3,4,4a,5,8,8a-octahydro-

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 Nov 2010 - 11 Feb 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to OECD and EC test Guidelines and in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes (incl. QA statement)

Remarks:

The study report includes a certificate of GLP compliance issued by the MHRA.

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

(3R,6S,9E)-9-ethylidenetetracyclo[6.2.1.1³,⁶.0²,⁷]dodec-4-ene; (3S,6R,9E)-9-ethylidenetetracyclo[6.2.1.1³,⁶.0²,⁷]dodec-4-ene

EC Number:

700-518-3

Cas Number:

38233-76-0

Molecular formula:

C14H18

IUPAC Name:

(3R,6S,9E)-9-ethylidenetetracyclo[6.2.1.1³,⁶.0²,⁷]dodec-4-ene; (3S,6R,9E)-9-ethylidenetetracyclo[6.2.1.1³,⁶.0²,⁷]dodec-4-ene

Details on test material:

- Name of test material (as cited in study report): ETD (Chemical name: ETD (Ed-TCD))
- Substance type: organic
- Physical state: Transparent liquid
- Analytical purity: c.a. 100%
- Lot/batch No.: M0901
- Expiration date of the lot/batch: End of December 2011
- Storage condition of test material: In the dark, refrigerated (c.a. 4°C)

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: UK
- Age at study initiation: Approximately eight to twelve weeks of age prior to dosing on Day 1
- Weight at study initiation: 17.4 to 22.4 g
- Housing: Animals were housed in solid bottomed polycarbonate cages with a stainless steel mesh lid. Each cage contained a quantity of autoclaved wood flake bedding, additionally Nestlets and a plastic shelter were included for environmental enrichment.
- Diet (e.g. ad libitum): Free access to Rat and Mouse No. 1 Maintenance Diet
- Water (e.g. ad libitum): Potable water taken from the public supply was made freely available
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 23
- Humidity (%): 40-70
- Photoperiod (hrs dark / hrs light): 12hrs light/12 hours dark

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

25, 50% v/v in acetone:olive oil (4:1 v/v) and ‘as supplied’

No. of animals per dose:

- Preliminary study: 2
- Main study: 4

Details on study design:

RANGE FINDING TESTS:
Compound solubility: A vehicle trial performed with ETD showed that it formed a pale clear yellow liquid at 50% v/v in 4:1 v/v acetone:olive oil (AOO)
- Irritation: An assessment of local irritation was performed and an erythema score greater or equal to 3 and/or an increase in ear thickness of greater than 25% at Day 3 or 6 compared with predose was regarded as irritation which precludes the use of that concentration on the main study.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Skin sensitisation: Local Lymph Node Assay
- Criteria used to consider a positive response: A stimulation Index (SI) was determined as the ratio of disintegrations per minute (DPM) between each sample and the control group. The uptake of 3H-Methyl Thymidine by a suspension containing Lymph Node Cells (LNC) was measured in terms of DPM and is a measure of the sensitisation potential of the test substance. The material was considered to be a sensitiser of the SI was greater than 3.

TREATMENT PREPARATION AND ADMINISTRATION: The test substance (25 µL) was applied to the dorsal surface of each ear using an automatic micropipette and was spread over the entire dorsal surface of the ear using the tip of the pipette. Further groups of four mice received the vehicle alone or the positive control substance in the same manner.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:

The SI for the positive control substance hexyl cinnamic aldehyde (HCA), was 11.4 which demonstrates the validity of this study.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

The SI (test/control ratios) obtained for 25, 50% v/v and ‘as supplied’ ETD were 5.8, 6.8 and 7.2 respectively. As a SI of 3 or more was recorded for all three of the concentrations tested, ETD was considered to have the potential to cause skin sensitization.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

Group no: Concentration: dpm: 3 AOO 3836.85 4 25 % v/v 22335.95 5 50 % v/v 25997.65 6 As supplied 27746.05 7 HCA 25% v/v 43865.85

Applicant's summary and conclusion

Interpretation of results:

sensitising

Remarks:

Migrated information

Conclusions:

ETD is regarded as a potential skin sensitizer. Due to the nature of the dose response, it was not possible to extrapolate an EC3 value from the lowest two doses, however it can be concluded that the EC3 value is below the lowest concentration tested.