Registration Dossier

Administrative data

Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18 July 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report Date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
Version / remarks:
2015
Deviations:
no
Qualifier:
according to
Guideline:
other: EU Method B.40 BIS: "In Vitro Skin Corrosion: Human Skin Model Test"
Version / remarks:
2008
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Appearance: Greenish brown crystalline powder
- Storage conditions of test material: At room temperature
- Stable until: 10 June 2021 (expiry date)
Specific details on test material used for the study:
No correction factor required.

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Justification for test system used:
Recommended test system in international guidelines
Vehicle:
unchanged (no vehicle)
Details on test system:
TEST SYSTEM
- Model: human three dimensional epidermal model

CELL CULTURE
- MTT medium: MTT concentrate (5 mg/mL) diluted (1:5) with MTT diluent (supplemented DMEM).
- Environmental conditions: All incubations were carried out in a controlled environment, in which optimal conditions were a humid atmosphere of 80 to 100 %, containing 5.0 ± 0.5 % CO2 in air in the dark at 37.0 ± 1.0 °C.

TEST FOR THE INTERFERENCE OF THE TEST MATERIAL WITH THE MTT ENDPOINT
A test material may interfere with the MTT endpoint if it is coloured and/or it is able to directly reduce MTT. The cell viability measurement is affected only if the test material is present on the tissues when the MTT viability test is performed.

TEST FOR COLOUR INTERFERENCE BY THE TEST MATERIAL
The test material was checked for possible colour interference before the study was started. Some non-coloured test materials may change into coloured materials in aqueous conditions and thus stain the skin tissues during the 1-hour exposure. To assess the colour interference, at least 25 mg of test material or 50 μL Milli-Q water as a negative control were added to 0.3 mL Milli-Q water. The mixture was incubated for approximately 1 hour at 37.0 ± 1.0 °C in the dark. At the end of the exposure time the mixture was shaken and it was checked if a blue / purple colour change was observed.

TEST FOR REDUCTION OF MTT BY THE TEST MATERIAL
The test material was checked for possible direct MTT reduction before the study was started. To assess the ability of the test material to reduce MTT, at least 25 mg was added to 1 mL MTT solution (1 mg/mL) in phosphate buffered saline. The mixture was incubated for approximately 1 hour at 37.0 ± 1.0 °C. A negative control, sterile Milli-Q water was tested concurrently. At the end of the exposure time it was checked if a blue / purple colour change or a blue / purple precipitate was observed.
Control samples:
yes, concurrent negative control

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Remarks on result:
not determinable because of methodological limitations
Other effects / acceptance of results:
TEST FOR COLOUR INTERFERENCE BY THE TEST MATERIAL
Since the test material induces colour interference in aqueous conditions and was considered to be not compatible with the test system, the test was not conducted.

Applicant's summary and conclusion

Interpretation of results:
study cannot be used for classification
Remarks:
Not possible to conduct full study
Conclusions:
Under the conditions of the study, the test material was not compatible with the test system and no conclusion could be made on the corrosive potential of the test material.
Executive summary:

The potential of the test material to cause skin corrosion was assessed in an in vitro skin corrosion test using a human skin model in accordance with the standardised guidelines OECD 431 and EU Method B.40 bis under GLP conditions.

The test material was checked for possible colour interference with the MTT endpoint and for the non-specific reduction of MTT by the test material. No non-specific reduction of MTT by the test material was shown. However, the test material was positive for colour interference and the compound was considered to be incompatible with the test system.

Under the conditions of the study, the test material was not compatible with the test system and no conclusion could be made on the corrosive potential of the test material.