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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 January 2017 - 17 February 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
Version / remarks:
29 July 2016
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: EU method B.40 BIS (In Vitro Skin corrosion: Human Skin Model Test), adopted 31 May 2008
Version / remarks:
31 May 2008
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
Reaction products of Resin acids and Rosin acids, sodium salts and barium chloride
Molecular formula:
not applicable
IUPAC Name:
Reaction products of Resin acids and Rosin acids, sodium salts and barium chloride
Test material form:
solid: particulate/powder
Details on test material:
Name as cited in the report: Barium salts of resin acids and rosin acids
Appearance: light tan powder
Storage conditions: at room temperature desiccated

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Cell source:
skin obtained from plastic surgery from multiple donors
Justification for test system used:
Recommended test system in international guidelines (OECD and EC).
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ Skin Model (EPI-200)
- Tissue lot number: 24982 kit I and H
- Tissue surface: 0.6 cm²
- All cells used to produce Eipderm™ are purchased or derived from tissue obtained by MatTek Corporation from acredited institutions.
- Cells are screened for potential biological contaminants (HIV-1, Hepatitis B, Hepatitis C, bacteria, yeast and fungi)

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: All incubations, with the exception of the test item incubation of 3 minutes at room temperature, were carried out in a controlled environment at 37.0 ± 1.0°C (actual range 36.9 - 37.0°C).

REMOVAL OF TEST MATERIAL AND CONTROLS
- After the exposure period, the tissues were washed with phosphate buffered saline to remove residual test item.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 h
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 2 replicates per exposure duration, one negative control, one positive contol.

ACCEPTANCE OF RESULTS:
The in vitro skin corrosion test is considered acceptable if it meets the following criteria:
a) The absolute mean OD570 of the two tissues of the negative control should reasonably be within the laboratory historical control data range.
b) The mean relative tissue viability following 3-minute exposure to the positive control should be ≤ 30%.
c) In the range of 20 – 100% viability, the maximum inter-tissue variability (in viability) is ≤ 30% between two tissues treated identically.
d) In the range of 20 – 100% viability, the maximum difference in percentage between the mean viability of two tissues and one of the two tissues is ≤ 15%.

DECISION CRITERIA: see table 1
Control samples:
yes, concurrent negative control
yes, concurrent positive control
yes, concurrent MTT non-specific colour control
other: concurrent control for MTT reduction by test item
Amount/concentration applied:
25.9 to 35.0 mg of test item on the skins moistened with 25 μl Milli-Q water
Duration of treatment / exposure:
3-minute and 1-hour
Duration of post-treatment incubation (if applicable):
none

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
3-minute exposure
Value:
110
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Remarks:
(100%)
Positive controls validity:
valid
Remarks:
(29%)
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
1-hour exposure
Value:
95
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Remarks:
(100%)
Positive controls validity:
valid
Remarks:
(9%)
Other effects / acceptance of results:
- OTHER EFFECTS:
- Direct-MTT reduction: No
- Colour interference with MTT: No

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes, mean relative tissue viability was 9% following 1-hour of exposure.
- Acceptance criteria met for variability between replicate measurements: No, the Coefficient of Variation between tissue replicates of the positive controls was 38.7% at the 3-minute treatment which is not within the acceptability criteria (≤30%). However, since both individual tissues of the positive control were clearly positive, this deviation was considered to have an adverse effect on the study.

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 Barium salts of resin acids and rosin acids is considered to be not corrosive.

- Table 1 shows the mean tissue viability with the first and the second set of negative controls, table 2 shows the results of individual OD measurements at 570 nm.

Any other information on results incl. tables

Table 1 Individual OD measurements at 570 nm.

 

3-minute application (OD570)

1-hour application (OD570)

 

A

B

A

B

Negative control

 

 

 

 

OD570measurement 1

1.4908

1.4308

1.7312

1.5932

OD570measurement 2

1.4052

1.3742

1.7305

1.5681

OD570measurement 3

1.4427

1.4020

1.6864

1.5657

D&C Red 6

 

 

 

 

OD570measurement 1

1.5878

1.5922

1.5747

1.5914

OD570measurement 2

1.5390

1.5627

1.5478

1.5672

OD570measurement 3

1.5732

1.5369

1.5616

1.5763

Positive control

 

 

 

 

OD570measurement 1

0.5413

0.3585

0.1999

0.1843

OD570measurement 2

0.5453

0.3446

0.2067

0.1793

OD570measurement 3

0.5385

0.3422

0.2032

0.1789

OD = Optical density

Duplicate exposures are indicated by A and B.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
An in vitro skin corrosion test was conducted with Barium salts of resin acids and rosin acids according to OECD 431 guideline and GLP principles. It is concluded that this test is valid and that the test substance is not corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.
Executive summary:

In an in vitro skin corrosion test using a human skin model (EpiDerm Skin Model, Lot no.: 24982 kit I and H), the influence of the test substance on the viability of human skin was tested. At least twenty-five mg of Barium salts of resin acids and rosin acids was applied directly to 0.6 cm2 cultured skin, which was moistened with 25 μl of Milli-Q water. After 3-minute and 1-hour treatments the substance was removed and the viability of the cells was tested by reduction of MTT. Viability of unexposed skin was set at 100%. The positive control had a mean relative tissue viability of 9% after the 1-hour exposure. The absolute mean OD570 of the negative control tissues was within acceptance limits (OECD 431) and the laboratory historical control data range. The coefficient of variation between tissue replicates was 9% for the test item and negative control. For the positive control, the Coefficient of Variation between tissue replicates at the 3-minute exposure was 38.7%. However, because both individual tissues of the positive control were clearly positive it was concluded that the test system functioned properly and the study was considered to be valid. Since the mean relative tissue viability was not below 50% after the 3-minute treatment and not below 15% after the 1-hour treatment, it can be concluded that Barium salts of resin acids and rosin acids is not corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.