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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:
23/02/2017-02/03/2017
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:
(butylamine)[[2,2'-thiobis[4-(1,1,3,3-tetramethylbutyl)phenolato]](2-)-O,O',S]nickel
EC Number:
238-523-3
EC Name:
(butylamine)[[2,2'-thiobis[4-(1,1,3,3-tetramethylbutyl)phenolato]](2-)-O,O',S]nickel
Cas Number:
14516-71-3
Molecular formula:
C32H51NNiO2S
IUPAC Name:
2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and batch No.of test material: Baoding 20161221
- Expiration date of the batch:20-12-2018
- Purity: 99.1%
- Purity test date: 21-12-2016

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Vehicle:
unchanged (no vehicle)
Details on test system:
TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 3 mins at room temperature and 60 minutes at 37±1°C
- Temperature of post-treatment incubation (if applicable): 37±1°C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: Tissues were thoroughly rinsed and blotted to remove the test substance/controls.
- Observable damage in the tissue due to washing: None noted
- Modifications to validated SOP: None

DYE BINDING METHOD
- Dye used in the dye-binding assay: MTT
- Spectrophotometer: Libra S22
- Wavelength: 570 nm
Control samples:
yes, concurrent negative control
yes, concurrent positive control
yes, concurrent MTT non-specific colour control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL H2O

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): 8N KOH
Duration of treatment / exposure:
3 and 60 mins
Duration of post-treatment incubation (if applicable):
After rinsing, tissues were transferred to 24-well plates containing MTT medium and incubated at culture conditions for 3 hours.
Number of replicates:
3

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
3 mins
Value:
107
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks:
8.5
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
60 minutes
Value:
93.4
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks:
3.9
Other effects / acceptance of results:
- OTHER EFFECTS:
- Direct-MTT reduction: The test substance did not change colour of MTT medium (see Figure 1). The test substance does not reduce MTT directly.

- Colour interference with MTT:
Water: The test substance is hydrophobic. After incubation water remained clear and colourless (see Figure 2).
Isopropyl alkohol : The test substance is insoluble. After incubation, the test substance solvent remained colourless, slightly clouded. The colour of the test substance did not interfere with evaluation.


ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The assay meets the acceptance criterion - OD570 of the NC tissues was 1.655 (3 min) and 1.709 (60 min) which is ≥ 0.8 and ≤ 2.8.

- Acceptance criteria met for positive control: Viability of tissues treated with 8N KOH after 60 minutes treatment was 3.9 % which is <15%

- Acceptance criteria met for variability between replicate measurements: CV values in all triplets of tissues were ≤ 0.3 (see Table 1).

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the above-described experimental design, the test substance UV-1084 was non-corrosive in In vitro Skin Corrosion Test on EpiDermTM tissues.
Executive summary:

In an in vitro skin corrosion assay in a human epidermal model EpiDerm (17-164), water-moistened reconstructed human epidermis (RhE) tissue was exposed to 25 mg of UV-1084 (99.1%) for 3 and 60 minutes. Sterile water was used for the negative control and 8N KOH was used for the positive control. After rinsing, tissues were incubated with MTT for 3 hours and then extracted with isopropyl alcohol for 2 hours at room temperature with shaking. The OD570 of isopropyl alcohol extracts was measured on a spectrophotometer. Relative cell viability was calculated for each tissue as % of the mean viability of the negative control tissues.

The colour of the test substance did not interfere with the endpoint. The test substance is not directly MTT reducing. The negative control gave the appropriate response. The average viability of tissues treated with the test substance UV-1084 was 107 % of the negative control average value after 3 minutes treatment and 93.4 % after 60 minutes treatment. The average viability of positive control tissues at 3 and 60 minutes was 8.5% and 3.9%, respectively. The test substance UV1084 was non-corrosive in the EpiDermTM model.

This in vitro skin corrosion study in the human epidermal model EpiDermTM is acceptable and satisfies the guideline requirement for an OECD 431 study.