[2-(cyclohexyloxy)ethyl]benzene

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

Test is performed before October 2016 when the REACH regulation came into force requesting in vitro studies first

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 January - 7 March 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Reliability 2 is assigned because although the study was conducted similar to the OECD TG 406, the guideline is not referenced, also because the official guideline was established 2 months after the report of this study was completed. However, it is assumed that the authors of the report / study director followed a draft version of this guideline, which resulted in a study similar to the current OECD TG 406. Therefore, this did not influence the reliability of the results. Except for this, this study is probably non-GLP. Additionally, a diluent which was used to dilute the test substance for testing is unknown, as well as the positive control used. This is not expected to influence the positive results of this study.

Justification for type of information:

Test is performed before October 2016 when the REACH regulation came into force requesting in vitro studies first.

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 study has a number of limitations and deviations. The test substance was diluted with an unknown diluent. This is not expected to influence the positive results of this study. An unknown positive control was used.

GLP compliance:

no

Type of study:

Buehler test

Justification for non-LLNA method:

The skin sensitisation information is available before the LLNA guideline was initiated.

Test material

Test material information

1

Reference substance name:

[2-(cyclohexyloxy)ethyl]benzene

EC Number:

279-576-2

EC Name:

[2-(cyclohexyloxy)ethyl]benzene

Cas Number:

80858-47-5

Molecular formula:

C14H20O

IUPAC Name:

[2-(cyclohexyloxy)ethyl]benzene

Test material form:

liquid

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Remarks:

albino strain

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS:
- Source: Murphy Breeding Laboratories
- Age at Acclimatization Start: No information provided
- Weight at Acclimatization Start: 300-400 g
- Housing: individually in wire mesh cages, suspended above the droppings
- Diet: Purina Guinea Pig Chow was available ad libitum throughout the study
- Water: First, the animals were maintained on medicated water containing 4% of sulfaethoxypyridazine for four days. At the end of this period, they were furnished with non-medicated water ad libitum.
- Acclimation period: at least one week.

ENVIRONMENTAL CONDITIONS:
- Temperature (°C): No information provided
- Humidity (%): No information provided
- Air changes (per hr): No information provided
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, occlusive

Vehicle:

not specified

Concentration / amount:

Test substance was used at 3% in the amount of 0.4 ml.

Day(s)/duration:

The exposure was done for 6-6.5 hours once each week for three weeks.

Adequacy of induction:

other: Concentration causing a very mild irritation

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

not specified

Concentration / amount:

Test substance was used at 3% in the amount of 0.4 ml.

Day(s)/duration:

The exposure was done for 6 and one-quarter hours.

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Test animals: 15
Control animals: 15 (10 used as positive controls and 5 as negative controls)

Details on study design:

RANGE FINDING TESTS
- Topical application:
Prior to the induction phase of the study, the test material was applied to four additional guinea pigs to determine the highest non-irritating concentration which could be applied for the inductions and the primary challenge. For this purpose, the test substance was tested as 25%, 12.5%, 6.0% and 3.0% v/v solutions in the diluent. On the day before applications, the backs of the guinea pigs were clipped with electric clippers. This provided space to test four concentrations on each guinea pig. On the following day, a patch was applied for six hours to each animal using 0.4 ml of each test solution.
On the day following application, the clipped areas were depilated with Neet Cream Hair Remover. The depilatory was allowed to remain on the sites for 30 minutes and then washed off with warm tap water. The patch sites were scored for irritation approximately five hours later.

MAIN STUDY
A. INDUCTION EXPOSURE
Topical applications
- Concentration: 3.0%
- Amount: 0.4 ml
- Area: 4 cm2
- Exposure length: 6-6.5 hours (occlusive)
- Exposure period: the patches were reapplied to the same site once each week for a total of three applications.

B. CHALLENGE EXPOSURE (control and test group)
- Day of challenge: 2 weeks after the epidermal induction application
- Concentration of test substance: 3.0% (amount: 0.4 ml)
- Concentration of the positive control: 0.1% w/v solution (amount: 0.4 ml)
- Negative control: 100% diluent (amount: 0.4 ml)
- Exposure period: 6 and one-quarter hours (occlusive)
- Sites: fresh application site, different from the induction site, the lower left quadrant of the backs of animals
- Readings: 24 and 48 hours after patch removal.

Challenge controls:

The positive controls received 0.4 ml of the positive control substance as a 0.1% w/v solution in the diluent, and the negative controls received 0.4 ml of 100% diluent. The exposure time and technique was as described for the animals receiving the test substance.

Positive control substance(s):

yes

Remarks:

A positive control was used in this study, however the identification of this substance is not given.

Results and discussion

Positive control results:

For the positive control animals, two scores of 2, five scores of 1, and three scores of +/- were noted at the 24-hour reading and six scores of 1, three scores of +/- and one score of 0 were noted at the 48-hour reading.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0%

No. with + reactions:

1

Total no. in group:

5

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0%

No. with + reactions:

1

Total no. in group:

5

Results 3

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

3.0%

No. with + reactions:

8

Total no. in group:

15

Remarks on result:

positive indication of skin sensitisation

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

3.0%

No. with + reactions:

8

Total no. in group:

15

Remarks on result:

positive indication of skin sensitisation

Any other information on results incl. tables

Irritative effects noted during the pilot test of the test substance included two scores of 1 and two scores of +/- as a 25% v/v solution, two scores of 1 and two scores of +/- as a 12.5% v/v solution, two scores of 1, one score of +/- and one score of 0 as a 6.0% v/v solution and two scores of +/- and two scores of 0 as a 3.0% v/v solution. Based upon the results of the pilot test, a concentration of 3.0% v/v was selected as the concentration to be used for the induction and challenge of the test animals.

Applicant's summary and conclusion

Interpretation of results:

other: Skin sensitising (Category 1B)

Remarks:

According to EU CLP 1272/2008 and its amendments.

Conclusions:

In a guinea pig Buehler test performed similar to OECD 406 (1981), the substance is considered a skin sensitiser.

Executive summary:

The skin sentisation potential of the substance was investigated by performing a guinea pig Buehler test similar to OECD 406 (1981). Fifteen albino guinea pigs (males and females) were used. A concentration of 3% was used for the topical induction and for the challenge as the highest non-irritating concentration, based on the previous range finding test. At the both 24-hour and 48-hour readings, the test substance group showed a reaction in 8 out of 15 animals. This result is in the range for 1B sensitizer classification: between 15 and 60% of animals responding at a dose between 0.2 and 20%. Based on the results of the present study, the substance is considered to be a skin sensitiser. Despite the concentration not being an irritant during the induction, the results are acceptable in view of the sensitization seen.