Trans-2-{4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3,5-difluorophenyl}-5-(trans-4-propylcyclohexyl)-1,3-dioxane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 6, 2011 - October 25, 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Council Regulation (EC) No. 761/2009 laying down test methods pursuant to Regulation (EC) No. 1907/2006 of the European Parliament and the council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2010

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Skinethic skin irritation test -42bis Standard operating procedure (SOP) 2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Trans-2-{4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3,5-difluorophenyl}-5-(trans-4-propylcyclohexyl)-1,3-dioxane

EC Number:

700-701-8

Cas Number:

798556-07-7

Molecular formula:

C26H27F7O3

IUPAC Name:

Trans-2-{4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3,5-difluorophenyl}-5-(trans-4-propylcyclohexyl)-1,3-dioxane

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

standard model

Vehicle:

unchanged (no vehicle)

Remarks:

No vehicle used in this study; The test item was applied neat to the tissues.

Details on test system:

CELL CULTURE
- Supplier: SkinEthic Laboratories (Nice, France)
- Source: human keratinocytes cultured on a polycarbonate filter in conditions which permit their terminal differentiation
- Format: 24 well plate
- Batch: 11 022A 0809


TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment: room temperature
- Temperature of post-treatment incubation: 37°C

REMOVAL OF THE TEST MATERIAL AND CONTROL
After the end of the treatment interval, the residual test item was removed immediately by gently rinsing with a minimum volume of 25 mL PBS using a pipette. Excess PBS was removed by gently shaking the inserts and blotting the bottom with blotting paper.

DYE BINDING METHOD
- Dye used in the dye-binding assay: MTT
- Spectrophotometer:ELx800, BioTek Instruments GmbH, Bad Friedrichshall, Germany at 570 nm

Control samples:

yes, concurrent negative control

Amount/concentration applied:

TEST MATERIAL: 16 mg of solid test material
NEGATIVE CONTROL: 16 µL (Phosphate-Buffered Saline)
POSITIVE CONTROL: 16 µL (5% aqueous solution of sodium dodecyl sulfate in deionised water)

Duration of treatment / exposure:

42 min (± 1 minute)

Duration of post-treatment incubation (if applicable):

42 hours (± 1 hour)

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Experiment 1 / Run 1

Value:

100.34

Vehicle controls validity:

not applicable

Remarks:

The test item was applied neat to the tissues

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: none
- Direct-MTT reduction: none
- Colour interference with MTT: none

ACCEPTANCE OF RESULTS:
After treatment with the negative control the absorbance values reached a mean OD of 2.11 (SD 5.96 %). Therefore, the negative control fulfilled the validity criteria.
Treatment with the positive control revealed a mean relative viability of 1.36 % (SD 4.03 %), thus the positive control reached the validity criteria.

Any other information on results incl. tables

Group	Time / [min]	Mean OD	Mean Relative viability / [%]
Negative Control	42	2.111	100
Positive Control	42	0.029	1.36
Test Material	42	2.118	100.34

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 439. Under the experimental conditions reported, the test material is not irritating to the skin.

Executive summary:

This in vitro study was performed to assess the irritation potential of the test item by means of the Reconstructed Human Epidermis Test and in accordance with OECD TG 439. The test consisted of a topical exposure of the test material to a human reconstructed model followed by a cell viability test. Cell viability was quantitatively measured by dehydrogenase conversion of MTT into a blue formazan salt after extraction from tissues. The percent reduction of cell viability in comparison to untreated negative controls was used to predict skin irritation potential. Triplicates of the human skin model RHE (Reconstructed Human Epidermis, SkinEthic) were treated with the test material, the negative or the positive control for 42 minutes (± 1 minute).
16 µL of either the negative control (PBS-buffer) or the positive control (aqueous solution of sodium dodecyl sulfate) were applied to each tissue. Before adding the solid test material, 10 µL of deionised water was spread to the epidermis surface to improve further contact between the test material and the epidermis. Afterwards, 16 mg of the test material were applied to each tissue. Treatment with the positive control induced a sufficient decrease in the relative absorbance as compared to the negative control for the treatment interval thus ensuring the validity of the test system. After treatment with the negative control the absorbance values reached the required acceptability criterion of a mean optical density (OD) ≥ 1.2 and ≤ 2.5 for the treatment interval thus showing the quality of the tissues.

The tissue viability after treatment with the test material was higher than 50 % (mean viability: 100.34 %). Therefore, the test material is not considered to possess an irritant potential to the skin. In conclusion, under the experimental conditions reported, the test material is not irritating to the skin.