1,3,4,6,7,8a-hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18th June 2016 - 27th July 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

1,3,4,6,7,8a-hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one

EC Number:

245-890-3

EC Name:

1,3,4,6,7,8a-hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methanonaphthalen-8(5H)-one

Cas Number:

23787-90-8

Molecular formula:

C15H24O

IUPAC Name:

1,1,5,5-tetramethylhexahydro-2H-2,4a-methanonaphthalen-8(5H)-one

Test material form:

other: Liquid

Details on test material:

Name: Isolongifolanone
Manufacturer's code: 545103
Sample description: Almost colourless oily liquid
Purity: Non-GLP 66 %
Calculated moleuclar weight: 220.0
% carbon: GLP 79.1 %
Storage conditions: Store at room temperature in the dark.

In vitro test system

Details on the study design:

N/A

In chemico test system

Details on the study design:

N/A

In vivo test system

Test animals

Species:

mouse

Strain:

CBA:J

Sex:

female

Details on test animals and environmental conditions:

Mouse, CBA/J strain, inbred, SPF-Quality.
Recognized by the international guidelines as the recommended test system (e.g. OECD, EC, EPA).
Source: Janvier, Le Genest-Saint-Isle, France

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

25, 50 or 100%

No. of animals per dose:

5

Details on study design:

Three groups of five animals were treated with one test item concentration per group. The highest test item concentration was selected from the pre-screen test.
One group of five animals was treated with the vehicle.

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

1.8

Test group / Remarks:

25% Concentration

Results 2

Parameter:

SI

Value:

4.4

Test group / Remarks:

50% Concentration

Results 3

Parameter:

SI

Value:

11.9

Test group / Remarks:

100% Concentration

Results 4

Parameter:

EC3

Value:

36.5

Any other information on results incl. tables

Two animals dosed at 100% and one animal dosed at 50% showed clinical signs. Since the concentrations were not tolerated well by these animals, these animals were excluded from interpretation. Mean DPM/animal values for the remaining experimental animals treated with test item concentrations 25, 50 and 100% were 625, 1566 and 4206 DPM, respectively. The mean DPM/animal value for the vehicle control group was 353 DPM. The SI values calculated for the test item concentrations 25, 50 and 100% were 1.8, 4.4 and 11.9, respectively.

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Executive summary:

These results indicate that the test item could elicit a SI ≥ 3. The data showed a dose-response and an EC3 value (the estimated test item concentration that will give a SI =3) of 36.5% was calculated.

However, it cannot be excluded that the scabs on the ears and the display of systemic toxicity by the test item did have an influence on the activity of the nodes.

Overall it was considered that there was sufficient evidence that Isolongifolanone would be regarded as skin sensitizer based on the recommendations made in the test guidelines.