2,6-dimethyloctan-2-ol

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 Jan - 10 Feb 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

No 761/2009

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: UN GHS

Version / remarks:

published 2003, last (6th) revision 2015

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

2,6-dimethyloctan-2-ol

EC Number:

242-361-9

EC Name:

2,6-dimethyloctan-2-ol

Cas Number:

18479-57-7

Molecular formula:

C10H22O

IUPAC Name:

2,6-dimethyloctan-2-ol

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: SkinEthic Laboratories, Lyon, France

Source strain:

other: not applicable

Justification for test system used:

According to testing guideline OECD Guideline 439

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN TM
- Tissue batch number(s): 17-EKIN-006
- Production date/Shipping date: no data
- Delivery date: 07 February 2017
- Date of initiation of testing: 07 February 2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure/ post-treatment incubation: 37 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Tissues were washed with phosphate buffered saline to remove residual test item.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/ml in PBS
- Incubation time: 3 hours at 37 °C
- Spectrophotometer: not specified
- Wavelength: 570 nm
- Filter: no information

NUMBER OF REPLICATE TISSUES: 3

DECISION CRITERIA
- A test substance 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 substance and 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
- A test substance 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 substance 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(s) applied (volume or weight with unit): 10 μL

Duration of treatment / exposure:

15 minutes

Duration of post-treatment incubation (if applicable):

42 hours

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Relative mean tissue viability compared to the negative control tissues (100%)

Value:

13.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks:

9.7

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Direct-MTT reduction: No colour changes observed
- Colour interference with MTT: No colour changes observed

ACCEPTANCE OF RESULTS:
-The relative mean tissue viability for the positive control treated tissues was 9.7% relative to the negative control treated tissues and the standard deviation value of the viability was 13.8%. The positive control
acceptance criteria were therefore satisfied.
-The mean OD570 for the negative control treated tissues was between ≥ 0.6 and ≤ 1.5 and the standard deviation value of the viability was 13.9%. The negative control acceptance criteria were therefore satisfied.
-The standard deviation calculated from individual tissue viabilities of the three identically test item treated tissues was 8.0%. The test item acceptance criterion was therefore satisfied.

Any other information on results incl. tables

Results after treatment with Tetrahydro Myrcenol and controls

Test Group	Mean Absorbance of 3 Tissues	Relative Absorbance [%] Tissue 1, 2 + 3**	Relative Standard Deviation [%]	Rel. Absorbance [% of Negative Control]***
Negative Control	0.888	101.0 / 113.4 / 85.6	13.9	100.0
Positive Control	0.086	8.4 / 9.6 / 11.1	13.8	9.7
Test Item	0.119	12.7 / 12.8 / 14.6	8.0	13.4

* Mean of two replicate wells after blank correction

** relative absorbance per tissue [rounded values]

*** relative absorbance per treatment group [rounded values]

Applicant's summary and conclusion

Interpretation of results:

other: Skin irritant Category 2

Remarks:

according to EU CLP criteria (1272/2008/EC and its updates)

Conclusions:

Under the conditions of this test, the relative mean tissue viability for the test item determined to be 13.4%. This value is below the threshold for irritancy of ≤50%.

Executive summary:

The possible skin irritation potential of Tetrahydro Myrcenol was tested in vitro using a human skin model through topical application for 15 minutes. The study procedures described in this report were according to OECD TG 439 guideline and GLP principles. Skin tissue was treated by topical application of 10 μL undiluted test substance. After 42 hours post-incubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) MTT at the end of treatment. Skin irritation is expressed as the remaining cell viability after exposure to the test substance. Reliable negative and positive controls were included. The positive control had a mean cell viability of 9.7% after 15 minutes exposure. The standard deviation value of the percentage viability of three tissues treated identically was less than 18%, indicating that the test system functioned properly. Under the conditions of this test, the relative mean tissue viability for the test item determined to be 13.4%. This value is below the threshold for irritancy of ≤50%. Based on the results obtained, it can be concluded that Tetrahydromyrcenol is category 2 skin irritant.