3-ethoxy-4,6-difluoro-7-hexyloxy-dibenzothiophene

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Apr 17, 2018 - Jun 28, 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

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:

July 26, 2013

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Council Regulation (EC) No. 440/2008 laying down test methods pursuant to Regulation (EC) No. 1907/2006. B.40.bis. In vitro skin corrosion: human skin model test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

5-ethoxy-6,10-difluoro-11-(hexyloxy)-8-thiatricyclo[7.4.0.0²,⁷]trideca-1(9),2(7),3,5,10,12-hexaene

EC Number:

950-069-4

Molecular formula:

C20H22F2O2S

IUPAC Name:

5-ethoxy-6,10-difluoro-11-(hexyloxy)-8-thiatricyclo[7.4.0.0²,⁷]trideca-1(9),2(7),3,5,10,12-hexaene

Test material form:

solid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

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: EpiSkin/SkinEthic Laboratories, Lyon, France)
- Source: human keratinocytes cultured on a polycarbonate filter in conditions which permit their terminal differentiation
- Format: 24 well plate
- Batch: 19-RHE-087
- Expires: May 27, 2019

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
At the end of the exposure periods, the test item, positive and negative control was removed immediately by gently rinsing with a minimum volume of 20 mL DPBS using a pipette. Excess DPBS was removed by gently shaking the tissue inserts and blotting the bottom of the tissue inserts with blotting paper.

Control samples:

yes, concurrent negative control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 16 mg of solid test material
- Concentration (if solution): n/a

VEHICLE
- Amount(s) applied (volume or weight with unit): n/a
- Concentration (if solution): n/a
- Lot/batch no. (if required): n/a
- Purity: n/a

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 16 µl (deionised water )
- Concentration (if solution): n/a

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 16 µl
- Concentration (if solution): A dodecyl sulfate sodium salt solution dissolved deionised water pure was used as positive control.

Duration of treatment / exposure:

42 min

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:

Mean relative viability in %

Value:

92.4

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:


-Acceptability of the Quality Control Data of the Skin Model with Reference to Historical Batch Data:
The OD values for the negative control shall be in the range of ≥ 0.8 and ≤ 3.0 as given in OECD Guideline 439

-Acceptability of the Positive and Negative Control:
The negative control data meet the acceptance criteria if the mean OD value is higher or equal than a historically established boundary at 570 nm. The boundary is two standard deviations below the current historical mean (1.416).
The positive control data meet the acceptance criteria if the mean viability value, expressed as % of the negative control, is lower than or equal to a historically established boundary. The boundary is three standard deviations above the current historical mean (2.77%).



-Test Substance Data Acceptance Criteria:
The standard deviation between the three tissues replicates treated with the test item was 4.9% and, thus, ≤18%.


The study met all acceptance criteria.

Any other information on results incl. tables

Group	Time / [min]	Mean OD	Mean Relative viability / [%]
Negative Control	42	1.810	100.0
Positive Control	42	0.024	1.3
Test Material	42	1.672	92.4

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Non-corrosive

Conclusions:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 439. Under the conditions of the present study, the test item is not considered to be irritant to skin.

Executive summary:

Objective

The objective of the present study was to investigate the potential of the test item to induce skin corrosion in anin vitrohuman skin model.

Study Design

This in vitro study was performed to assess the irritation potential of the test material by means of the Reconstructed Human Epidermis Test. The test consisted of a topical exposure of the test item to a human reconstructed skin 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 the skin irritation potential.

Triplicates of the human skin RHE(TM)-model were treated with the test item, the negative or the positive control for 42 minutes (± 1 minute). 16 µL of either the negative control (DPBS-buffer) or the positive control (5% aqueous solution of sodium dodecyl sulfate) were applied to the tissues. Before adding the solid test item, 10 µL of deionised water was spread to the epidermis surface to improve the contact between the test item and the epidermis. Afterwards, 16 mg of the test item were applied to the tissues.

Results

All acceptability criteria after treatment with the negative control (DPBS-buffer) and the positive control (5% aqueous solution of sodium dodecyl sulfate) were met.

Following treatment with the test item, the tissue viability was 92.4% and, thus, higher than 50%, i.e. according to OECD 439 the test item is considered as non-irritant to skin (UN GHS: No Category).

Conclusion

Under the conditions of the present study, the test item is not considered to possess an irritating/corrosive potential to skin.