1,1'-(1,1,3-trimethylpropane-1,3-diyl)bis(cyclohexane)

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 to 20 August 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

2012

Deviations:

no

GLP compliance:

yes

Test material

Test material information

1

Reference substance name:

1,1'-(1,1,3-trimethylpropane-1,3-diyl)bis(cyclohexane)

EC Number:

254-227-7

EC Name:

1,1'-(1,1,3-trimethylpropane-1,3-diyl)bis(cyclohexane)

Cas Number:

38970-72-8

Molecular formula:

C18H34

IUPAC Name:

(4-cyclohexyl-4-methylpentan-2-yl)cyclohexane

Specific details on test material used for the study:

Appearance: Clear colourless liquid
Batch: 170918339
Purity: 97.2%

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Details on animal used as source of test system:

Source: SkinEthic Laboratories, Lyon, France
EPISKIN-SMTM, 0.38 cm2, Batch no.: 18 EKIN 033

Justification for test system used:

In the interest of sound science and animal welfare, a sequential testing strategy is recommended to minimize the need of in vivo testing. One of the validated in vitro skin irritation tests is the EPISKIN test, which is recommended in international guidelines (e.g. OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

SKIN TEST SYSTEM PREPARATION
- Procedure used: The liquid test item was applied undiluted (25 µL) was added into 12-well plates directly on top of the tissue

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37.0 ± 1.0°C (actual range 36.7 - 37.4°C)
- Temperature of post-treatment incubation: 37.0 ± 1.0°C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: The tissues were washed with phosphate buffered saline to remove residual test item. After rinsing, the cell culture inserts were each dried carefully and moved to a new well on 2 mL pre-warmed maintenance medium until all tissues were dosed and rinsed. Subsequently the skin tissues were incubated for 42 hours at 37°C.

DYE BINDING METHOD
- Dye used in the dye-binding assay: MTT
- Wavelength: 570 nm

NUMBER OF INDEPENDENT TESTING RUNS / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1 (The test was performed on a total of 3 tissues per test item together with negative and positive controls).

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- A test item is considered irritant in the skin irritation test if: The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
- A test item is considered non-irritant in the in vitro skin irritation test if: The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is > 50% of the mean viability of the negative controls.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 25 µL

NEGATIVE CONTROL Phosphate bufered saline
- Amount applied: 25 µL

POSITIVE CONTROL 5% (aq) Sodium dodecyl sulfate
- Amount applied: 25 µL

Duration of treatment / exposure:

Exposure period of 15 ± 0.5 minutes at room temperature

Duration of post-treatment incubation (if applicable):

42 hours at 37°C

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

91

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Colour interference with MTT: No

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes
- Acceptance criteria met for variability between replicate measurements: Yes

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions of this in vitro skin irritation test using the EPISKIN model, 1,1’-(1,1,3-trimethylpropane-1,3-diyl)bis(cyclohexane) is a non-irritant.

Executive summary:

Under the experimental conditions of this in vitro skin irritation test using the EPISKIN model, 1,1’-(1,1,3-trimethylpropane-1,3-diyl)bis(cyclohexane) is a  non-irritant.