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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:
From 24 February 2016 to 24 March 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 430 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test Method (TER))
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:
liquid
Details on test material:
- Stabilisation: in water undergoes hydrolysis
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Purity: 92%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature and humidity avoided

In vitro test system

Test system:
isolated skin discs
Source species:
rat
Cell type:
non-transformed keratinocytes
Cell source:
foreskin from multiple donors
Source strain:
Wistar
Details on animal used as source of test system:
SOURCE ANIMAL
- Source: Centre for Experimental Medicine at the Medical University in Katowice
- Sex: females
- Age at study initiation (in days): 21 days old.
- Housing: plastic cage (58 x 37 x 21 cm) covered with a wire bar lid.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 3 days
Justification for test system used:
A transcutaneous electrical resistance test (TER) is an important step when trying to predict and evaluate toxic properties of a given test item. It is performed in order to obtain information on risks resulting from skin contact with this test item, whereas the obtained results may be used to classify it. The in vitro skin corrosivity study was performed in order to obtain information on health hazards resulting from skin contact with the test item. Corrosive materials are identified on the basis of their ability to produce a loss of normal stratum corneum integrity and barrier function, which is measured as a reduction in the TER below a threshold level for this method (5 kΩ).
Vehicle:
unchanged (no vehicle)
Details on test system:
SKIN DISC PREPARATION
- Procedure used: The animals were euthanized and the dorso-lateral skin of each animal was removed and stripped of excess subcutaneous fat. The skin discs were cut out using a scalpel. Each skin disc was placed over one of the ends of a PTFE (polytetrafluoroethylene) tube. The skin disc were fully submerged in a MgSO4 solution.
- Quality control for skin discs: Electrical resistance obtained with two of the isolated skin discs was greater than 10 kΩ

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 21-22°C.

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps:1
- Modifications to validated SOP: no

DYE BINDING METHOD
- Dye used in the dye-binding assay: The dye binding procedure was not necessary in this case since all TER values for the test item were higher than 5 kΩ and there were not any visible changes on the skin discs

NUMBER OF INDEPENDENT TESTING RUNS / EXPERIMENTS TO DERIVE FINAL PREDICTION: 2 (two animals 3 skin disc per animal)

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the mean TER value is less than or equal to 5 kΩ and the skin disk is obviously damaged.
- The test substance is considered to be non-corrosive to skin if the mean TER value obtained for the test substance is greater than 5 kΩ, or if the mean TER value is less than or equal to 5 kΩ, and the skin disc is showing no obvious damage.
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 150 μL
- Concentration (if solution): undiluted (100%)

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 150 μL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 150 μL
- Concentration (if solution): 10M hydrochloric acid
Duration of treatment / exposure:
24 hours
Duration of post-treatment incubation (if applicable):
Not applicable
Number of replicates:
3

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
animal 1 skin disc 1
Value:
19.01
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
animal 1 skin disk 2
Value:
19.75
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
animal 1 skin disc 3
Value:
19.96
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
mean animal 1
Value:
19.57
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
animal 2 skin disc 1
Value:
17.31
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
animal 2 skin disc 2
Value:
17.95
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
animal 2 skin disc 3
Value:
18.09
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
transcutaneous electrical resistance (in kΩ)
Run / experiment:
mean animal 2
Value:
17.78
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Other effects / acceptance of results:
- OTHER EFFECTS:
- Visible damage on test system: no

DEMONSTRATION OF TECHNICAL PROFICIENCY: yes

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes
- Acceptance criteria met for variability between replicate measurements: yes

Any other information on results incl. tables

Before the beginning of the experiment, the electrical resistance of two skin discs was measured for each animal skin (animals no. 1 and 2). In each case, the skin discs gave the resistance values greater than 10 kΩ; therefore, the remainder of the skin discs of the animals could have been used in the experiment.

Results of the control transcutaneous electrical resistance test (TER):

Animal number

Skin disc number

TER value (kQ)

1

1

11.37

2

13.95

2

1

12.36

2

14.07

Experiment: results of the transcutaneous electrical resistance test (TER):

Animal

number

Tested substance

Skin disc number

TER value (kQ)

Mean TER valueSD (kO)

1

Positive control - 10M HCl

1

0.92

0.92 ± 0.01

2

0.91

3

0.92

Negative control - distilled water

1

16.21

16.77±0.49

2

17.13

3

16.98

Test item

1

19.01

19.57±0.50

2

19.75

3

19.96

2

Positive control - 10M HCl

1

0.93

0.92 ± 0.01

2

0.92

3

0.92

Negative control - distilled water

1

16.75

16.77±0.25

2

17.03

3

16.54

Test item

1

17.31

17.78±0.42

2

17.95

3

18.09

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item is not skin corrosive when it is tested in skin discs of Wistar rats.
Executive summary:

The skin corrosion potential of the test substance was determined in accordance with the OECD nº 430 with GLP. A transcutaneous electrical resistance test (TER) was performed on skin discs of Wistar female rats in order to obtain information on health hazards resulting from skin contact with the test item. At the beginning of the experiment, the animals were 21 days old. In order to control the procedure quality, the electrical resistance of two skin discs obtained from each test animal was measured before the start of the experiment. In each case, the skin disc resistance values were greater than 10 kΩ; therefore, the remainder of the animals’ skin discs could have been used in the experiment. The undiluted test item was uniformly applied to the epidermal surface of the skin disc placed inside a tube. Concurrent positive (10M hydrochloric acid) and negative (distilled water) controls were used. Three skin discs obtained from each animal were used for the test item and three for each control item. The test item and the control items were evenly applied to the discs for 24 hours and kept at 21-22°C. Then, they were removed by washing with a jet of tap water. LCR 6401 low-voltage, alternating current databridge was used to measure the electrical resistance of the skin in kΩby placing the databridge electrodes on either side of the skin disc. After the transcutaneous electrical resistance test (TER), the skin discs were subjected to a gross examination in order to reveal possible damage. The dye binding procedure was not necessary in this case since all TER values for the test item were higher than 5 kΩand there were not any visible changes on the skin discs. The mean TER results for the skin discs treated with the test item were equal to 19.57 kΩ (animal no. 1) and 17.78 kΩ (animal no. 2). They can be accepted because the concurrent positive and negative control values fell within the acceptable ranges for the method. Gross examinations of the skin discs treated with the test item did not reveal any pathological changes. On the grounds of the study, it may be stated that the test substance does not lead skin corrosion/severe irritation.