1,2,3,5,6,7-hexahydro-1,1,2,3,3-pentamethyl-4H-inden-4-one

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 October 2011 - 9 February 2012

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)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (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:

1,2,3,5,6,7-hexahydro-1,1,2,3,3-pentamethyl-4H-inden-4-one

EC Number:

251-649-3

EC Name:

1,2,3,5,6,7-hexahydro-1,1,2,3,3-pentamethyl-4H-inden-4-one

Cas Number:

33704-61-9

Molecular formula:

C14H22O

IUPAC Name:

1,1,2,3,3-pentamethyl-2,3,4,5,6,7-hexahydro-1H-inden-4-one

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 15 - 23 g
- Housing: individually, in suspended solid-floor propylene cages furnished with softwood woodflakes
- Diet (e.g. ad libitum): ad libitum, 2014C Teklad Global Rodent Diet
- Water (e.g. ad libitum): ad libitum, tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: To:

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

25%, 50%, 100%

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Concentration: Daily treatment for 3 consecutive days (application of 25µL undiluted test item to the dorsal surface of each ear).
- Irritation: No signs of systemic toxicity, visual local skin irritation or irritation indicated by an equal to or greater than 25% increase in mean ear thickness were noted. Based on this information the undiluted test item and the test item at concentrations of 50% and 25% v/v in acetone/olive oil 4:1 were selected for the main test.
- Lymph node proliferation response:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay (LLNA) - individual animal approach
- Criteria used to consider a positive response (DSD/CLP): Stimulation Index (SI) > 3

TREATMENT PREPARATION AND ADMINISTRATION:
- The mice were treated by daily application of 25µL of the appropriate concentration of the test item to the dorsal surface of each ear for three consecutive days.
- The test item was formulated within two hours of being applied to the test system. It is assumed that the formulation was stable for this duration.

Positive control substance(s):

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

Statistics:

Data was processed to give group mean values for disintegrations per minute and standard deviations where appropriate. Individual and group mean disintegrations per minute values were assessed for dose reponse relationships by analysis of homogeneity of variance followed by one way analysis of variance (ANOVA). In the event of a significant result from the ANOVA, pairwise comparisons were performed between control and treated groups. For homogenous datasets Dunnett's Multiple Comparison test was used and for non-homogenous datasets Dunnett's T3 Multiple Comparison Method was used.

Results and discussion

Positive control results:

SI expressed as the mean radioactive incorporation for α-Hexylcinnamaldehyde was 7.67, which is a positive result (SI > 3).

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

2.69

Test group / Remarks:

25%

Results 2

Key result

Parameter:

SI

Value:

3.66

Test group / Remarks:

50%

Results 3

Key result

Parameter:

SI

Value:

3.52

Test group / Remarks:

100%

Results 4

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean DPM/animal (Standard Deviation) - Vehicle (0%): 2295.90 (± 789.82) - 25%: 6168.85 (± 2029.92) - 50% 8413.63 (± 1117.15) - 100% 8073.27 (± 3667.10)

Any other information on results incl. tables

- Clinical observations and mortality data: There were no deaths. No signs of systemic toxicity were noted in the test or control animals during the test.

- Bodyweight: Bodyweight changes of the test animals between Day 1 and Day 6 were comparable to those observed in the corresponding control group animals over the same period.

- An EC3 value of 33% was calculated using this equation: EC3 = c + [[(3-d)/(b-d)] x (a-c)].

Applicant's summary and conclusion

Interpretation of results:

other: Substance is a skin sensitiser (1B)

Remarks:

accordance with EU CLP (1272/2008 and its amendments)

Conclusions:

The substance is a skin sensitiser (1B) in the Local Lymph node assay (OECD guideline 429).

Executive summary:

This Local Lymph Node Assay (OECD TG 429) was performed to determine the sensitising potential of Cashmeran in mice. Groups of 5 mice were treated with the undiluted Cashmeran or Cashmeran at concentrations of 50% or 25% v/v in acetone/olive oil 4:1.α-Hexylcinnamaldehyde, freshly prepared as a 25% v/v dilution in acetone/olive oil 4:1, was used as positive control. Clinical observations and bodyweights were recorded and lymph node proliferation was determined using 3HTdR incorporation. The number of radioactive disintegrations per minute (dpm) reflect the proliferation reponse of lymph node cells, and were 2295.90, 6168.85, 8413.63, and 8073.27 mean dpm/animal for the 0%, 25%, 50%, and 100% concentration groups, respectively. This corresponds with a lymph node proliferation of 2.69, 3.66 and 3.52, respectively, for the Cashmeran-treated groups, calculated as the Stimulation Index (SI). No mortality and no signs of systemic toxicity were observed. No effects on bodyweight (gain) were observed. An EC3 value (the concentration of test item expected to cause a 3 -fold increase in 3HTdR incorporation) of 33% was calculated. Based on the absence of effects at the lowest concentration tested, a NOEC of 25% could be established. Under the conditions of this study, a maximum SI of 3.66 was calculated. Considering the SI threshold of 3 as stated in Annex I of 1272/2008/EC, the substance needs to be classified as sensitiser for concentrations ≥ 33%.