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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
From 2017-10-31 to 2017-11-06
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Version / remarks:
2015
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
2-[4-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)phenyl]butyric acid
EC Number:
303-995-2
EC Name:
2-[4-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)phenyl]butyric acid
Cas Number:
94232-67-4
Molecular formula:
C18H15NO4
IUPAC Name:
2-[4-(1,3-dioxo-2,3-dihydro-1H-isoindol-2-yl)phenyl]butanoic acid
Specific details on test material used for the study:
Batch No.: 17001R73A
Purity: 102%

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Justification for test system used:
In the interest of sound science and animal welfare, a sequential testing strategy is recommended to minimize 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:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN Small Model TM
- Tissue batch number(s): 17 EKIN 044
- Date of initiation of testing: 31 Oct 2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 15 ± 0.5 minutes at room temperature, others at 37.0 ± 1.0°C
- Temperature of post-treatment incubation (if applicable): incubated for 42 hours at 37°C.

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: washed with phosphate buffered saline to remove residual test item. After rinsing, the cell culture inserts were each dried carefully and moved to a new well on 2 mL pre-warmed maintenance medium until all tissues were dosed and rinsed.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 3 tissues per test item together with negative and positive controls.

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be irritant to skin if the relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is < 50% of the mean viability of the negative controls.
- The test substance is considered to be non-irritant to skin if the relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is > 50% of the mean viability of the negative controls.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10.8 to 15.8 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 25 μL PBS

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 25 μL 5% SDS
Duration of treatment / exposure:
15 ± 0.5 minutes
Duration of post-treatment incubation (if applicable):
42 hours

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Value:
99
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with the test item
Other effects / acceptance of results:
OTHER EFFECTS:
- Possible direct MTT reduction and color interference: no color changes observed, the test item did not interact with the MTT endpoint.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: the absolute mean OD570 of the negative control tissues was within the laboratory historical control data range.
- Acceptance criteria met for positive control: the positive control had a mean cell viability after 15 ± 0.5 minutes exposure of 10%.
- Acceptance criteria met for variability between replicate measurements: The standard deviation value of the percentage viability of three tissues treated identically was <6%, indicating that the test system functioned properly.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item is non-irritant in the in vitro skin irritation test under the experimental conditions described in this report.
Executive summary:

The objective of this study was to evaluate Test item for its ability to induce skin irritation on a human three dimensional epidermal model (EPISKIN Small model (EPISKIN-SMTM)). The possible skin irritation potential of the test item 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.

Skin tissue was moistened with 5 μL of Milli-Q water and at least 10 mg of the test item was applied 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.

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 the test item compared to the negative control tissues was 99%. Since the mean relative tissue viability for the test item was above 50% after 15 ± 0.5 minutes treatment the test item is considered to be non-irritant.

In conclusion, test item is non-irritant in the in vitro skin irritation test under the experimental conditions described in this report.