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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin corrosion: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
24 Jun 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
Version / remarks:
adopted in 2004
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
Version / remarks:
adopted in 2019
Deviations:
yes
Remarks:
limited details on model (barrier function, morphology, quality control), no check for direct MTT reduction or colour interference, acceptance and evaluation criteria differ from current guideline, no historical control data, no positive control included
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Cell source:
other: CellSystems, St. Katharinen, Germany
Source strain:
other: EST-1000 reconstructed human epidermis
Details on animal used as source of test system:
Not applicable
Justification for test system used:
Reconstructed human epidermis is the recommended test system for in vitro predicting of a corrosive potential.
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EST-1000 (CellSystems, St. Katharinen, Germany)
- Tissue batch number: EST-90427-001
- Date of initiation of testing: 24 Jun 2009

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 3 min at room temperature and 60 min at 37.0 ± 2 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: After the incubation period the tissues were carefully washed with PBS.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 2 h
- Spectrophotometer: EL808, Bio-Tek
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 3

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: A single experiment was performed.

PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.
Control samples:
yes, concurrent negative control
Amount/concentration applied:
TEST MATERIAL
- Amount applied: The skin was moistened with 50 µL 0.9% NaCl and 25 mg of the solid test item were added on top of the skin tissues.

NEGATIVE CONTROL
- Amount applied: 50 µL
Duration of treatment / exposure:
3 and 60 min
Number of replicates:
triplicates for each treatment and control group

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Remarks:
mean value of 3 tissues
Run / experiment:
3 min exposure
Value:
94.43
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Remarks:
The reliability of the test method was confirmed prior to the experimental study by interlaboratory validation.
Irritation / corrosion parameter:
% tissue viability
Remarks:
mean value of 3 tissues
Run / experiment:
60 min exposure
Value:
100.89
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Remarks:
The reliability of the test method was confirmed prior to the experimental study by interlaboratory validation.

Any other information on results incl. tables

Table 1: Summary of results on skin corrosion

 Sample Exposure time   OD ± SD  % Viability
 Test item 3 min   1.68 ± 0.08  94.43
 0.9% NaCl 3 min   1.78 ± 0.20  100.00
 Test item  60 min  1.74 ± 0.11  100.89
 0.9% NaCl  60 min  1.72 ± 0.14  100.00

OD: Optical densitiy, mean of 6 values

SD: Standard deviation

Applicant's summary and conclusion

Interpretation of results:
other: Not corrosive
Conclusions:
The substance was tested for corrositivity in vitro according to OECD guideline 431 using reconstructed human skin as test system. The result revealed no corrosive property of the test item. There is regulatory acceptance in the EU that a substance can be considered corrosive (Skin Corrosive Cat.1A) based on a positive result in the human epidermis model test. Negative in vitro corrosivity responses are not conclusive with respect to non-classification or classification as irritant and shall therefore be subject to further evaluation.