Reaction mass of 1,2,3,4,5,6,7,8-octahydro-5,5-dimethylnaphthalene-2-carbaldehyde and 1,2,3,4,5,6,7,8-octahydro-8,8-dimethyl-2-naphthaldehyde

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 September 2008 - 18 September 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

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:

EPA OPPTS 870.2600 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 1,2,3,4,5,6,7,8-octahydro-5,5-dimethylnaphthalene-2-carbaldehyde and 1,2,3,4,5,6,7,8-octahydro-8,8-dimethyl-2-naphthaldehyde

EC Number:

916-807-4

Molecular formula:

C13H20O

IUPAC Name:

Reaction mass of 1,2,3,4,5,6,7,8-octahydro-5,5-dimethylnaphthalene-2-carbaldehyde and 1,2,3,4,5,6,7,8-octahydro-8,8-dimethyl-2-naphthaldehyde

Test material form:

liquid

Specific details on test material used for the study:

- Expiration date: Augustus 2009
- Storage conditions: 15-30°C
- Physical condition: Clear colorless liquid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA:J

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Jackson Laboratories, Bar Harbor, ME 04609
- Age at study initiation: 10-12 weeks
- Weight at study initiation: 21-25 gram
- Housing: Animals were group housed 5 per cage
- Diet: Harlan Teklad Certified Rodent Chow 7012C, ad libitum
- Water: Tap water, ad libitum
- Acclimation period: six days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.3 - 23.3
- Humidity (%): 43 - 81
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

other: 1:3 Diethyl phthalate/Ethanol

Concentration:

1, 2.5, 5, 10, 25% (v/v)

No. of animals per dose:

5

Details on study design:

In-Life Observations and Measurements
- Mortality/Morbidity: Daily on days 1 to 6
- Clinical Observations: Observations were performed prior to dose administration and following dose administration. Clinical observations were performed once daily on days 4-6. Particular attention was given to the application sites. Any significant alteration to the application sites, and the general appearance of the pinnae, including build up of test article, was recorded.
- Dermal irritation: Animals were examined daily for signs of erythema and edema. Irritation was scored an recorded using the Draize scoring system. Scoring was performed prior to dosing on days 1-3.
- Body weight: Animals were weighted on days 1 and 6.

Method of performance
- Mice were treated on the dorsal surface of both ears (25 µL/ear), once per day on days 1, 2, and 3. Approximately 24±2 hours between applications of test article was maintained. On day 6 the mice were injected i.v. with 20 µCi of 3H-thymidine in 250 µl of sterile saline. Five hours later the mice were euthanized by CO2 asphyxiation and the draining auricular lymph nodes were removed. At removal, the number of nodes collected per animal was recorded, and the nodes were examined for size/appearance and the data recorded. Any unexpected observations were noted in study records. The lymph nodes from each group were pooled and a single cell suspension was prepared. Cells were washed twice with phosphate buffered saline (PBS) and precipitated with 5% trichloroacetic acid (TCA) overnight at 2-8°C. The pellets were recovered by centrifugation and resuspended in 1 mL of TCA and transferred to a vial containing scintillation fluid. An additional 1 mL of TCA was used to rinse the tube, and it was also transferred to the scintillation fluid. Incorporation of 3H-thymidine was measured in a beta-scintillation counter. DPM for each group was determined Increases in 3H-thymidine incorporation relative to the vehicle-treated control was derived for each group and recorded as stimulation indices (SI).

Positive control substance(s):

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

Statistics:

SYSTAT version 9.01 F developed by SPSS, Inc was used for statistical analysis. Body weights on Days 1 and 6 and body weight changes were also evaluated using SYS TAT version 9.01. The evaluation of the equality of means for body weight data was made by a one-way analysis of variance using the F distribution to assess statistical significance. If statistically significant differences between the means are found, a Dunnett's test was used to determine the degree of significance from the control means.

Results and discussion

Positive control results:

In September 2008, for HCA, SI of 5.5, 6.1, and 19.5 were determined at concentrations of 5, 15, and 35%, respectively.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

4.2

Test group / Remarks:

5 animals per group

Results 2

Parameter:

SI

Value:

1.2

Test group / Remarks:

1%

Results 3

Parameter:

SI

Value:

1.9

Test group / Remarks:

2.5%

Results 4

Parameter:

SI

Value:

3.5

Test group / Remarks:

5%

Results 5

Parameter:

SI

Value:

3.6

Test group / Remarks:

10%

Results 6

Parameter:

SI

Value:

12.8

Test group / Remarks:

25%

Cellular proliferation data / Observations:

- Mortality: There was no mortality and all animals appeared normal throughout the study.
- Clinical Observations: No erythema or edema was noted in any of the mice in the vehicle group or in those dosed with the test article at 1, 2.5, 5, 10 or 25% (v/v). Ears appeared wet in mice treated with 25% from days 2-4. There were no other findings.
- Body Weights: The mean body weights of the mice treated on days 1 and 6 showed no statistically significant differences. Therefore, administration of the test article did not appear to exert overt toxicity.
- Local Lymph Node Assay: At termination, the lymph nodes from the mice in the vehicle group and the test article treated animals at 1, 2 5, 5, or 10% (v/v) were normal in size and appearance with the exception of lymph nodes from mice treated with 25% were enlarged but appeared normal. Exposure to 1, 2.5, 5, 10 or 25% (v/v) resulted in stimulation indices of 1.2, 1.9, 3.5, 3.6, and 12.8, respectively. Since the data indicated a positive response the EC3 was calculated and determined to be 4.2%.

Applicant's summary and conclusion

Interpretation of results:

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