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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:
09 May 2016 to 06 June 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
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Qualifier:
according to guideline
Guideline:
EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)
Principles of method if other than guideline:
Any deviations from standard operating procedures were evaluated and filed in the study file. There were no deviations from standard operating procedures that affected the integrity of the study.
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
3-(p-cumenyl)-2-methylpropionaldehyde
EC Number:
229-695-0
EC Name:
3-(p-cumenyl)-2-methylpropionaldehyde
Cas Number:
6658-48-6
Molecular formula:
C14H20O
IUPAC Name:
3-(4-isopropylphenyl)-2-methylpropanal
Specific details on test material used for the study:
Name (as stated in the report): Silvial
Batch No.: SC00017272
Expiration date: 23 October 2016

In vitro test system

Test system:
human skin model
Remarks:
EPISKIN Small Model TM
Source species:
human
Cell type:
other: adult human-derived epidermal keratinocytes which have been seeded on a dermal substitute consisting of a collagen type I matrix coated with type IV collagen.
Cell source:
other: EPISKIN Small ModelTM (EPISKIN-SMTM, 0.38 cm2, Batch no.: 16-EKIN-022)
Source strain:
other: SkinEthic Laboratories, Lyon, France
Justification for test system used:
In the interest of sound science and animal welfare, a sequential testing strategy is recommended to
minimise the need of in vivo testing. One of the validated in vitro skin irritation tests is the EPISKIN test, which is recommended in international guidelines (e.g. OECD and EC).
Vehicle:
unchanged (no vehicle)
Details on test system:
EPISKIN Small ModelTM (EPISKIN-SMTM, 0.38 cm2, Batch no.: 16-EKIN-022)
This model is a three-dimensional human epidermis model, which consists of adult human-derived epidermal keratinocytes which have been seeded on a dermal substitute consisting of a collagen type
I matrix coated with type IV collagen. The keratinocytes were cultured for 13 days, which results in a highly differentiated and stratified epidermis model comprising the main basal, supra basal, spinous and granular layers and a functional stratum corneum.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
The liquid test item was applied undiluted (25 μl) directly on top of the tissue.
Duration of treatment / exposure:
15 ± 0.5 minutes
Duration of post-treatment incubation (if applicable):
42 hours at 37°C.
Number of replicates:
The test was performed on a total of 3 tissues per test item together with negative and positive controls.

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Remarks:
Mean tissue viability (percentage of control)
Value:
26
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
positive indication of irritation
Remarks:
Since the mean relative tissue viability for SILVIAL was below 50% it is considered to be irritant.
Other effects / acceptance of results:
The positive control had a mean cell viability after 15 ± 0.5 minutes exposure of 4.5%. The absolute mean OD570 of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was less than 8%, indicating that the test system functioned properly.

Applicant's summary and conclusion

Interpretation of results:
Category 2 (irritant) based on GHS criteria
Conclusions:
Finally, it is concluded that this test is valid and that SILVIAL is irritant in the in vitro skin irritation test under the experimental conditions described in this report.
Executive summary:

In vitro skin irritation test with SILVIAL using a human skin model.

This report describes the ability of SILVIAL to induce skin irritation on a human three dimensional epidermal model (EPISKIN Small model (EPISKIN-SMTM)). The possible skin irritation potential of SILVIAL was tested through topical application for 15 minutes.

The study procedures described in this report were based on the most recent OECD and EC guidelines.

Batch SC00017272 of SILVIAL was a colourless liquid. SILVIAL was applied undiluted (25 μl) directly on top of the skin tissue for 15 ± 0.5 minutes. After a 42 hour 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 MTT at the end of the treatment.

SILVIAL did interact with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT).

In addition to the normal procedure, three killed tissues treated with test item and three killed non-treated tissues were used for the cytotoxicity evaluation with MTT. The non-specific reduction of MTT by SILVIAL was -2.6% of the negative control tissues, therefore no correction was needed.

Skin irritation is expressed as the remaining cell viability after exposure to the test item. The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with SILVIAL compared to the negative control tissues was 26%. Since the mean relative tissue viability for SILVIAL was below 50% after 15 ± 0.5 minutes treatment it is considered to be irritant.

The positive control had a mean cell viability of 4.5% after 15 ± 0.5 minutes exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was less than 8%, indicating that the test system functioned properly.

Finally, it is concluded that this test is valid and that SILVIAL is irritant in the in vitro skin irritation test under the experimental conditions described in this report.