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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:
weight of evidence
Study period:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Well documented GLP study performed according to OECD guideline 431 and EU method B.40 BIS.

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: Human Skin Model Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of the test material (as cited in study reports): JNJ-63757109-AAA (T003690)
- Physical state: solid (powder)
- Appearance: white to slightly yellow power
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: I15HD2977
- Expiration date of the lot/batch: 2017-08-10
- Purity test date: no data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature
- Stability under test conditions: no data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The solid test item was applied directly on top of the skin tissue

In vitro test system

Test system:
human skin model
Remarks:
of human-derived epidermal keratinocytes
Source species:
human
Cell type:
non-transformed keratinocytes
Source strain:
other: not applicable
Vehicle:
unchanged (no vehicle)
Details on test system:
TEST SYSTEM
- EpiDerm Skin Model (EPI-200, Lot no.: 22684 kit U), supplied by MatTek Corporation, Ashland MA, U.S.A
- The model consists of normal, human-derived epidermal keratinocytes which have been cultured to form a multilayered, highly differentiated model of the human epidermis. It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo. The EpiDerm tissues (surface 0.6 cm²) were cultured on polycarbonate membranes of 10 mm cell culture inserts.

ENVIRONMENTAL CONDITIONS
- All incubations, with the exception of the test item incubation of 3 minutes at room temperature, were carried out in a controlled environment, in which optimal conditions were a humid atmosphere of 80 - 100% (actual range 63 - 86%), containing 5.0 ± 0.5% CO2 in air in the dark at 37.0 ± 1.0°C (actual range 36.3 - 36.7°C). Temperature and humidity were continuously monitored throughout the experiment. The CO2 percentage was monitored once on each working day. Temporary deviations from the temperature, humidity and CO2 percentage may occur due to opening and closing of the incubator door. Based on laboratory historical data these deviations are considered not to affect the study integrity.

CELL CULTURE
- Tissues: on the day of receipt the tissues were kept on agarose and stored in the refrigerator. On the next day, at least one hour before starting the assay the tissues were transferred to 6-well plates with 0.9 mL DMEM medium (Dulbecco’s Modified Eagle’s Medium) (supplemented DMEM medium, serum-free supplied by MatTek Corporation).
- MTT medium: MTT concentrate (5 mg/mL) diluted (1:5) with MTT diluent (supplemented DMEM). Both supplied by MatTek Corporation.

TEST FOR THE INTERFERENCE OF THE TEST ITEM WITH THE MTT ENDPOINT
A test item 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 item is present on the tissues when the MTT viability test is performed.

TEST FOR COLOUR INTERFERENCE BY THE TEST ITEM
The test item was checked for possible colour interference before the study was started. Some non-coloured test items may change into coloured substances in aqueous conditions and thus stain the skin tissues during the 1-hour exposure. To assess the colour interference, approximately 25 mg of the test item 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 ITEM
The test item was checked for possible direct MTT reduction before the study was started. To assess the ability of the test item to reduce MTT, approximately 25 mg of the test item was added to 1 ml MTT (Sigma, Zwijndrecht, The Netherlands) solution (1 mg/ml) in phosphate buffered saline. The mixture was incubated for approximately 1 hour at 37.0 ± 1.0ºC. 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 was observed.

APPLICATION/TREATMENT OF THE TEST ITEM
The skin tissues were kept in the refrigerator the day they were received. The next day, at least 1 hour before the assay was started the tissues were transferred to 6-well plates containing 0.9 ml DMEM medium per well. The level of the DMEM medium was just beneath the tissue (see fig 1). The plates were incubated for approximately 2 hours at 37.0 ± 1.0ºC. The medium was replaced with fresh DMEM medium just before the test item was applied.
After the exposure period, the tissues were washed with phosphate buffered saline (Invitrogen Corporation, Breda, The Netherlands) to remove residual test item . Rinsed tissues were kept in 24 well plates on 300 μl DMEM medium until 6 tissues (= one application time) were dosed and rinsed.

CELL VIABILITY MEASUREMENT
The DMEM medium was replaced by 300 μl MTT-medium and tissues were incubated for 3 hours at 37°C in air containing 5% CO2. After incubation the tissues were washed with PBS and formazan was extracted with 2 ml isopropanol (MatTek corporation) over night at room temperature. The amount of extracted formazan was determined spectrophotometrically at 570 nm in triplicate with the TECAN Infinite® M200 Pro Plate Reader.

Cell viability was calculated for each tissue as percentage of the mean of the negative control tissues. Skin corrosion potential of the test item was classified according to remaining cell viability following exposure of the test item with either of the two exposure times.

ELECTRONIC DATA CAPTURE
Observations/measurements in the study were recorded electronically using the following programme(s):
- REES Centron Environmental Monitoring system version SQL 2.0 (REES Scientific, Trenton, NJ, USA) for temperature and humidity.
- Magellan Tracker 7.0 (TECAN, Austria) for optical density measurement.

INTERPRETATION
A test item is considered corrosive in the skin corrosion test if:
a) The relative mean tissue viability obtained after the 3-minute treatment compared to the negative control tissues is decreased below 50%.
b) In addition, a test item considered non-corrosive (viability ≥ 50%) after the 3-minute treatment is considered corrosive if the relative tissue viability after 1-hour treatment with the test item is decreased below 15%.

A test item is considered non-corrosive in the in vitro skin corrosion test if:
a) The relative mean tissue viability obtained after the 3-minute treatment compared to the negative control tissues is not decreased below 50%.
b) In addition, the relative tissue viability after the 1-hour treatment is not decreased below 15%.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
Amounts applied:
- TEST ITEM: The skin was moistened with 25 μl Milli-Q water (Millipore Corp., Bedford, Mass., USA) to ensure close contact of the test item to the tissue and 31.5 to 35.0 mg of the solid test item (with a glass weight boat) was added into the 6-well plates on top of the skin tissues.
- NEGATIVE CONTROL (Milli-Q water): 50 µl
- POSITIVE CONTROL (8N KOH): 50 µl
Duration of treatment / exposure:
3 minutes and 1 hour
Number of replicates:
4 tissues per test item, negative control and positive control: 2 for the 3-minute exposure and 2 for the 1 hour-exposure

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
3-minute application
Value:
96
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: 94% and 99%
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
1-hour application
Value:
95
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: 97% and 92%
Irritation / corrosion parameter:
other: optical density
Run / experiment:
3-minute application
Value:
1.859
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: 1.813 and 1.906
Remarks:
SD: 0.066
Irritation / corrosion parameter:
other: optical density
Run / experiment:
1-hour application
Value:
1.832
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: 1.884 and 1.780
Remarks:
SD: 0.074
Other effects / acceptance of results:
The relative mean tissue viability obtained after the 3-minute and 1-hour treatments with the test item compared to the negative control tissues was 96% (94 and 99%) and 95% (97 and 92%) respectively. Because the mean relative tissue viability for the test item was not below 50% after 3 minutes treatment and not below 15% after 1 hour treatment the test item is considered to be not corrosive.

The test item was checked for colour interference in aqueous conditions and possible direct MTT reduction by adding the test item to MTT medium. Because the solutions did not turn blue / purple and a blue / purple precipitate was not observed it was concluded that the test item did not interfere with the MTT endpoint.

The mean relative tissue viability following 3-minute exposure to the positive control was 8% (8 and 8%) and 7% (one tissue) after 1 hour exposure.
The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range.
The maximum inter-tissue variability in viability between two tissues treated identically was less than 6% and the maximum difference in percentage between the mean viability of two tissues and one of the two tissues was less than 3%. It was therefore concluded that the test system functioned properly.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
This test was considered as valid and the test item was concluded to be non corrosive in the in vitro skin corrosion test under the experimental conditions described in the report.