Cyclohexanethiol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

between 01 February 2010 and 25 February 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was carried out in accordance with internationally valid GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

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:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

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:

Cyclohexanethiol

EC Number:

216-378-7

EC Name:

Cyclohexanethiol

Cas Number:

1569-69-3

Molecular formula:

C6H12S

IUPAC Name:

cyclohexanethiol

Constituent 2

Reference substance name:

CYCLOHEXYL MERCAPTAN

IUPAC Name:

CYCLOHEXYL MERCAPTAN

Test material form:

other: liquid

Details on test material:

purity: 99.85%
Description: clear colourless liquid
Batch number: 2009-06-1550
Date received 02 July 2009
Expiry date not supplied
Storage conditions room temperature in the dark

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBAlCa (CBAlCaOlaHsd)

Sex:

female

Details on test animals and environmental conditions:

On receipt the animals were randomly allocated to cages.
The animals were nulliparous and non-pregnant.
After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card.
At the start of the study the animals were: in the weight range of 15 to 23 g,
eight to twelve weeks old.
The animals were individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes.
Free access to mains tap water and food was allowed throughout the study.
The temperature and relative humidity were controlled to remain within target ranges of 19 to 25°C and 30 to 70%, respectively.
The rate of air exchange was approximately fifteen changes per hour.
The lighting was controlled by a time switch to give twelve hours continuous light (06.00 to 18.00) and twelve hours darkness.
The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

other: topical application to the dorsal surface of the ear

Vehicle:

other: the test material was used undiluted and freshly prepared as a solution in acetone/olive oil 4:1.

Induction 2

Concentration / amount:

Screening test: 100% and 50 %
Main test:25% , 50%

Challenge

Concentration / amount:

Screening test: 100% and 50 %
Main test:25% , 50%

No. of animals per dose:

5

Details on study design:

Groups of five mice were treated with the undiluted test material or the test material at concentrations of 50% or 25% v/v in acetone/olive oil 4:1. The preliminary screening test suggested that the test material would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. The mice were treated by daily application of 25 ~I of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The test material formulation was administered using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette.
A further group of five mice received the vehicle alone in the same manner.

Results and discussion

Any other information on results incl. tables

Main Test:

Estimation of the Proliferative Response of Lymph Node Cells

The radioactive disintegrations per minute per lymph nodes for each individual animal and the stimulation index are given in Table 2. The Stimulation Index expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group are as follows:

Concentration(%vlv) inacetone/oliveoi.1 4:1	Stimulation Index	Result
25	13.61	Positive
50	17.65	Positive
100	18.27	Positive

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.

Applicant's summary and conclusion

Conclusions:

The test material was considered to be a sensitiser under the conditions of the test.

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