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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:
19/07/2017-21/07/2017
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 guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
1,2-dihydro-1,2,4-triazol-3-one
Cas Number:
930-33-6
Molecular formula:
C2H3N3O
IUPAC Name:
1,2-dihydro-1,2,4-triazol-3-one
Test material form:
solid: crystalline
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: hemring/Batch 0727/16
- Expiration date of the lot/batch: 28 April 2019
- Purity test date: 99%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature in the dark
- Stability under test conditions: The test item was used as supplied.
- Solubility and stability of the test substance in the solvent/vehicle:
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The test item was used as supplied.
- Preliminary purification step (if any):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

FORM AS APPLIED IN THE TEST (if different from that of starting material)

TYPE OF BIOCIDE/PESTICIDE FORMULATION (if applicable)

OTHER SPECIFICS:

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Cell source:
other: Not specified
Source strain:
other: Epidermm Reconstructed Human Epidermis Model Kit
Details on animal used as source of test system:
NA
Vehicle:
unchanged (no vehicle)
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Duration of treatment / exposure:
3 and 60 minutes
Number of replicates:
2

Test animals

Species:
other: NA
Strain:
other: NA
Details on test animals or test system and environmental conditions:
NA

Test system

Type of coverage:
other: NA
Preparation of test site:
other: NA
Vehicle:
other: NA
Controls:
other: NA
Amount / concentration applied:
NA
Duration of treatment / exposure:
NA
Observation period:
NA
Number of animals:
NA
Details on study design:
NA

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
at 3 min
Value:
>= 87.2
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not valid
Remarks on result:
other: NA
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
at 60 min
Value:
>= 78
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: NA
Other effects / acceptance of results:
- OTHER EFFECTS:
- Visible damage on test system: The MTT solution containing the test item did not turn blue/purple. This was taken to indicate the test item did not reduce MTT
- Direct-MTT reduction: The MTT solution containing the test item did not turn blue/purple. This was taken to indicate the test item did not reduce MTT
- Colour interference with MTT: The solution containing the test item did not become colored. This was taken to indicate the test item did not have the potential to cause color interference.

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
- Range of historical values if different from the ones specified in the test guideline:

REMINDER ON QUALITY CRITERIA
The results of the assay are considered acceptable if the following assay acceptance criteria are achieved:
Negative Control
The absolute OD570 of the negative control treated tissues in the MTT-test is an indicator of tissue viability obtained in the testing laboratory after the shipping and storing procedure and under specific conditions of the assay. The mean OD570 of the two negative control tissues should be ≥ 0.8 and ≤ 2.8 for each exposure time, which ensures that the tissue viability meets the acceptance criteria.
Positive Control
Potassium Hydroxide 8.0N solution is used as a positive control. An assay meets the acceptance criterion if mean relative tissue viability of the 60 minute positive control is < 15%.
Coefficient of Variation
In the range 20 and 100% viability, the Coefficient of Variation between tissue replicates should be ≤ 30%.

Any other information on results incl. tables

Mean OD570 Values and Viabilities for the Negative Control Item, Positive Control Item and Test Item

Tissue Exposure period Mean OD570 of individual tissues Mean OD570 of duplicate tissues Standard deviation Coefficent of Variation (%) Relative Mean Viability
Negative control 3 minutes 2.000 2.098 0.134 6.4 100
2.190
60 minutes 2.122 2.057 0.092 4.5
1.992
Positive control 3 minutes 0.063 0.069 0.008 na 3.3
0.074
60 minutes 0.058 0.057 0.002 na 2.8
0.055
Test item 3 minutes 1.889 1.827 0.088 4.8 87.2
1.765
60 minutes 1.638 1.604 0.048 3.0 78.0
1.570

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item was considered to be non-corrosive to the skin.
Classification of corrosivity potential is based on relative viabilities for both exposure times according to the EU CLP Regulation (EC) No 1272/2008 UN GHS (cf table in the study report).
Executive summary:

In a in vitro EPIDERM skin Corrosion Test (Lacey F.E., 2018), performed according to the OECD guideline 431 and in compliance with GLP requirement, the corrosivity potential of the test item using the EpiDerm™ Human Skin Model was evaluated after treatment periods of 3 and 60 minutes.

Duplicate tissues were treated with the test item for exposure periods of 3 and 60 minutes. Negative (sterile distilled water) and positive (8.0N Potassiumm hydroxyde) control groups were treated for each exposure period. At the end of the exposure period, the test item was rinsed from each tissue before each tissue was taken for MTT-loading. After MTT loading each tissue was placed in 2 mL Isopropanol for MTT extraction.

At the end of the formazan extraction period each well was mixed thoroughly and triplicate 200 μL samples were transferred to the appropriate wells of a pre-labeled 96-well plate. The optical density (OD) was measured at 570 nm (OD570).

Data are presented in the form of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

The mean OD570 for the negative control treated tissues was 2.095 for the 3-Minute exposure period and 2.057 for the 60-Minute exposure period. The negative control acceptance criteria were therefore satisfied.

The relative mean tissue viability for the positive control treated tissues was 2.8% relative to the negative control following the 60-Minute exposure period. The positive control acceptance criterion was therefore satisfied.

In the range 20 to 100% viability the Coefficient of Variation between the two tissue replicates of each treatment group did not exceed 30%. The acceptance criterion was therefore satisfied.

The quality criteria required for acceptance of results in the test were satisfied.

The test item was considered to be non-corrosive to the skin.