1-ethynylcyclohexanol

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted in accordance with GLP.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

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)

Species:

mouse

Strain:

other: Pre-test: Mice, CBA/CaOlaHsd; Main Study: Mice, CBA/CaCrl

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source:
Pre-test: Harlan Laboratories B.V., Postbus 6174, 5960 AD Horst / The Netherlands
Main experiment: Charles River UK, Manston Road, Margate, Kent CT9 4LT, United Kingdom
- Age at study initiation: 8 – 9 weeks old (beginning of treatment)
- Weight at study initiation: 21.6 - 17.6 g (main experiment), 21.7 and 20.8 g (pre-test)
- Housing: Group
Cage Type: Makrolon Type II (pre-test)/ III (main study), with wire mesh top (EHRET GmbH, 79302 Emmendingen, Germany)
Bedding: Granulated soft wood bedding (Rettenmaier & Söhne GmbH + Co. KG, 73494 Rosenberg, Germany)
- Diet: Pelleted standard diet, ad libitum (Harlan Laboratories B.V., 5960 AD Horst, The Netherlands)
- Water: Tap water, ad libitum (Gemeindewerke, 64380 Rossdorf, Germany)
- Acclimation period: At least 5 days prior to the start of dosing under test conditions after health examination.
- Only animals without any visible signs of illness were used for the study.

ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 2°C
- Humidity: 31 – 65% (acclimation period); 45 – 65% (main study)
- Photoperiod (hrs dark / hrs light): Artificial light 6.00 a.m. - 6.00 p.m.

Vehicle:

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

Concentration:

Pre-test: 50 % solution in acetone:olive oil (4+1 v/v)
Main experiment: Vehicle Control (acetone:olive oil (4+1 v/v)); 10%, 25%, 50% solution

No. of animals per dose:

Pre-test: 2 animals
Main experiment: 5 animals per dose group

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: A solubility experiment was performed according to the recommendations given by OECD 429.
- Irritation: A pre-test was performed in two animals.
- Lymph node proliferation response: Eventual signs of local irritation were documented and the ear thickness was determined.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Proliferative response of the lymph node cells
- Criteria used to consider a positive response:
(i) incorporation of 3HTdR at least 3-fold or greater than that recorded in control mice (stimulation index)
(ii) data are compatible with a conventional dose response
(iii) cutoff-value for the lymph node cell count index: 1.55 (based on BALB/c mice)
(iv) cutoff-value for the ear weight index: 1.1 (based on BALB/c mice)

TREATMENT PREPARATION AND ADMINISTRATION:
- The test item mixed with acetone:olive oil (4+1 v/v) was added to achieve the required test substance concentration. The different test substance concentrations were prepared individually. The preparations were made freshly before each dosing occasion.
- A concentration control analysis of all three doses (and if applicable a homogeneity analysis of the lowest dose) was performed as a separate study.

Positive control substance(s):

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

Statistics:

The mean values and standard deviations were calculated for body weight, ear weight, lymph node weight and lymph node cell count, and for DPM values (group mean DPM ± standard deviation). For all statistical calculations SigmaStat for Windows (Version 2.0) was used. A One-Way-ANOVA was used as statistical method. In case of significant results of the One-Way-ANOVA, multiple comparisons were performed with the Dunnett test. Statistical significance was set at the five per cent level (p < 0.05). However, both biological and statistical significance were considered together.

Parameter:

SI

Remarks on result:

other: Vehicle Control: 1.00 10% solution: 0.87 25% solution: 0.85 50% solution: 1.22

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

Mean DPM per animal (2 lymph nodes)*: Vehicle Control: 1173.5 +/- 399.2 10% solution: 1016.1 +/- 443.9 25% solution: 1002.3 +/- 502.4 50% solution: 1428.3 +/- 696.7 *) Mean DPM/animal was determined by dividing the sum of the calculated values from lymph nodes of all animals within a group by the number of animals in that group (5 animals)

No deaths occurred during the study period. No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period. The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age.

The cutoff-value for the lymph node cell count index of 1.55 (reported for BALB/c mice) for a positive response was not exceeded in any of the tested dose groups. For BALB/c mice, a threshold for the ear weight index of 1.1 was reported for a positive response. None of the indices determined for the test item treated groups exceeded this threshold.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

LLNA:

A local lymph node assay (Harlan CCR, 2012) was performed in mice using test substance concentrations of 10, 25, and 50% (w/w). No deaths occurred during the study period. No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period. The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age. The DPM values did not show a statistically significant and biologically relevant increase in all dose groups in comparison to the vehicle control group. Stimulation Indices of 0.87, 0.85, and 1.22 were determined with the test substance at concentrations of 10, 25, and 50% (w/w) in acetone:olive oil (4+1 v/v), respectively (a test item is regarded as a sensitiser if exposure to one (or more) concentration results in a 3-fold or greater increase in incorporation of 3HTdR compared with concurrent controls, i.e. SI >= 3). In lymph node weight and lymph node cell count, a statistically significant and biologically relevant increase was not observed in any of the tested dose groups in comparison to the vehicle control group. The cutoff-value for the lymph node cell count index of 1.55 (reported for BALB/c mice) for a positive response was not exceeded in any of the tested dose groups. Furthermore, none of the indices determined for the test substance treated groups exceeded the threshold for the ear weight index of 1.1 (reported for BALB/c mice). Thus, 1-Ethinyl-1-cyclohexanol was not a skin sensitiser under the experimental conditions of this study performed according to OECD TG 429. The GLP-conform study is classified as acceptable (key study).

Migrated from Short description of key information:
1-Ethinyl-1-cyclohexanol was not a skin sensitiser in a reliable GLP-compliant Local Lymph Node Assay.

Justification for selection of skin sensitisation endpoint:
The key study was selected.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

There is no information available on the potential of 1-Ethinyl-1-cyclohexanol to produce respiratory sensitisation in animals.

 

Justification for classification or non-classification

Based on the results of the key skin sensitisation study (LLNA),1-Ethinyl-1-cyclohexanol would be not subject to classification as dermally sensitising substance according to the Directive 67/548/EEC and Regulation 1272/2008/EC.