2,4,6-trimethylcyclohex-3-ene-1-methanol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1981, June 1 - 1981, July 8

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

The in vivo information is retrieved from a Buehler test which was conducted before the REACH regulation on requesting in vitro information, came into force (October, 2016)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

1981

Deviations:

yes

Remarks:

The test item is from IFF and therefore according to internal standards. Ten animals are used in the treatment group and 5 in the negative control group in view of the positive result this does not affect the outcome of the study.

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

LLNA method was not available yet by the time the study was conducted. An appropriate Buehler test is available which would not justify conducting an additional LLNA due to animal welfare.

Test material

Test material information

1

Reference substance name:

rel-[(1R,2R,6R)-2,4,6-trimethylcyclohex-3-en-1-yl]methanol

Molecular formula:

C10H18O

IUPAC Name:

rel-[(1R,2R,6R)-2,4,6-trimethylcyclohex-3-en-1-yl]methanol

Test material form:

liquid

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Perfection Breeders, Inc., Douglasville, Pennsylvania
- Age at Acclimatization Start: No data
- Weight at Acclimatization Start: 290 - 500g
- Housing: Fill: two per cage in stainless steel wire mesh cages
- Diet: free access to Wayne Guinea Pig diet
- Water: free access to tap water
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS (set to maintain)
- Temperature (°C): 20 ± 3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

- IN-LIFE DATES: From: June 1, 1981 To: July 8, 1981

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, occlusive

Vehicle:

other: Ethanol

Concentration / amount:

test substance: 0.4 mL 60%

Day(s)/duration:

3 times/week for 3 weeks (total 9 exposures), 6 hours

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: Ethanol

Concentration / amount:

Test substance: 0.4 mL 60%

Day(s)/duration:

17 days after last induction, 6 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Test animals: 10
Positive Control animals: 10
Negative Control animals: 5

Details on study design:

RANGE FINDING TESTS
Four unexposed animals were exposed to 0.4 mL 20%, 40%, 60% and 100% concentration of the test substance by patching technique as described for main study. Treated sites were scored at 24 hours. The highest non-irritating concentration was 60%.



MAIN STUDY
A. INDUCTION EXPOSURE
The dorsal area of each animal was clipped free of hair 24 hours pior to the 1st, 4th, 6th and challenge applications of the test material. The shaved area was approx. 5 x 10 cm, i.e. 10% of the body surface. The test area was divided into three application sites, which were dosed on a rotating basis. The test material was applied beneath a 20 x 20 mm Webril pad on a 37 x 40 mm Readi-Bandage, and covered with dental dam held in place with a suitable bandage. Animals were exposed for 6 hours after which the dams and patches were removed. The treated sites were examined after each dosing day and scored at 24 and 48 hours. This procedure was performed three times weekly for three weeks (total 96-hour insults)

- Concentration: 60% in ethanol (control animals: ethanol 95% (negative) or 0.3% DNCB in 80% ethanol (positive))
- Amount: 0.4 mL
- Area: 4 cm2
- Exposure period: 6 hours (occlusive)
- Readings: 24 and 48 hours after patch removal

B. CHALLENGE EXPOSURE (control and test group)
Twenty-four hours after the challenge all animals were depilated with Neet Cream Hair Remover (Whitehalll Laboratories) for no more than 30 minutes after which the depilatory was thoroughly washed off.

- Day of challenge: approximately 17 days after last epidermal induction application
- Concentrations: 60%
- Exposure period: 6 hours (occlusive)
- Sites: site of sensitizing exposure and second naive site
- Amount: 0.4 mL
- Readings: 24 (a minimum of two hours after depilation) and 48 hours after patch removal

Challenge controls:

Control group was treated with 0.4 mLvehicle (Ethanol 95%) during induction phase and challenged with 0.4 mL 60% test substance.

Positive control substance(s):

yes

Remarks:

DNCB

Results and discussion

Positive control results:

The results of the positive control animals show that the system is responsive (9/10 and 5/10 animals reacted positive at the induction site and naive site, respectively)

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

other: negative control - induction and naive site

Dose level:

60%

No. with + reactions:

0

Total no. in group:

4

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

other: negative control - induction and naive site

Dose level:

60%

No. with + reactions:

0

Total no. in group:

4

Clinical observations:

None

Remarks on result:

no indication of skin sensitisation

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

other: test group - induction site

Dose level:

60%

No. with + reactions:

8

Total no. in group:

10

Clinical observations:

Animals showed slight or confluent or moderate patchy erythema (mean score 0.9)

Remarks on result:

positive indication of skin sensitisation

Results 4

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

other: test group - naive site

Dose level:

60%

No. with + reactions:

8

Total no. in group:

10

Clinical observations:

Animals showed slight or confluent or moderate patchy erythema (mean score 0.8)

Results 5

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

other: test group - induction site

Dose level:

60%

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

Animals showed slight or confluent or moderate patchy erythema (mean score 1.2)

Results 6

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

other: test group - naive site

Dose level:

60%

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

Animals showed slight or confluent or moderate patchy erythema (mean score 0.7)

Any other information on results incl. tables

Observations:

Slight edema was present and erythema was observed during induction at 48 hours post dose 3 with test material. In positive control animals erythema was observed during induction at 24 hours post dose 9 and 48 hours post dose 3, 4, and 8. No irritation was observed in the negative control animals during induction or challenge periods.

One control animal was found dead on day 29.

Applicant's summary and conclusion

Interpretation of results:

other: Sensitising

Remarks:

According to Regulation (EC) No. 1272/2008 and its amendments.

Conclusions:

In a Buehler test performed similar to OECD 406 (1981) and according to GLP principles, the substance is considered a skin sensitiser.

Executive summary:

The skin sentisation potential of the substance was investigated by performing a Buehler test similar to OECD 406 (1981) and according to GLP principles. Ten animals were used in the treatment group and 5 in the negative control group (instead of 20 resp. 10 animals according the guideline). A concentration of 60% was used for the inductions (total of 9) and the challenge. After the inductions, patchy erythema was observed among the animals. After the challenge with the substance 8 of the 10 and 7 of 10 animals showed slight or confluent or moderate patchy erythema (score 1) at the naive site at 24 and 48 hours, respectively. At the induction site slightly more effects were observed. Reliable negative (no response during challenge) and positive controls were included. Based on the positive results, the substance is considered to be a sensitiser under the conditions of the test.