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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:
02 October 2019 - 17 October 2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
Deviations:
yes
Remarks:
See " Principles of method if other than guideline"
Principles of method if other than guideline:
The CV value of the PC after 3 min was above 30% therefore, acceptance criterion 3 was not met. However, as this was borderline above 30% (31.196%), the PC values at 1 hour met their acceptance criteria and the overall result for the test item was not close to the borderline, this deviation was considered to have had no impact on the overall outcome of the study.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
impurity
Type:
Constituent
Test material form:
liquid

In vitro test system

Test system:
human skin model
Cell type:
non-transformed keratinocytes
Cell source:
other: Human-derived epidermal keratinocytes
Justification for test system used:
The EpiDermTM skin model and assay for skin corrosion testing is endorsed by OECD TG 431.
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: MatTek Corporation EpidermTM reconstructed tissue model: EPI-200
- Tissue batch number(s): Lot: 30831
- Delivery date: 15 October 2019
- Date of initiation of testing: 02 October 2019

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37°C, 5% CO2, Relative Humidity: ≥95%


MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- Incubation time: 60 minutes
- Spectrophotometer: BMG LabTech FluoStar Optima
- Wavelength: 570 nm
- Filter: no reference filter


FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: Pass
- Barrier function: Pass
- Morphology: Pass
- Contamination: Pass


NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE : Prior to the assay, the test item was checked for interference (water colouration or MTT interference) and found not to interfere.


NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 3 tissues per condition

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the relative tissue viability after 3 minutes treatment exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
- The test substance is considered to be non- corrosive to skin if the relative tissue viability after 3 minutes treatment exposure is more and after 1 hour is less than or equal to 15%.
- Justification for the selection of the cut-off point(s) if different than recommended in TG 431 and 439: Justification in accordance with Table 5 of testing guideline OECD 431
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Single topical administration of 50µl of neat test item
- Concentration (if solution): Undiluted

VEHICLE : Not used

NEGATIVE CONTROL : Sterile water (tissue grade) (Lot: RNBH4825)
- Amount(s) applied (volume or weight): 50µl
- Concentration (if solution): Neat

POSITIVE CONTROL : Potassium Hydroxide (Lot: H3410)
- Amount(s) applied (volume or weight): 50µl
- Concentration (if solution): 8N
Duration of treatment / exposure:
3 and 60 minutes
Number of replicates:
3

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
3 minutes
Value:
89.006
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
60 minutes
Value:
29.186
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: None reported
- Direct-MTT reduction: No direct reduction
- Colour interference with MTT: No colour interference


ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The mean OD570 of the negative control tissues must be ≥0.8. Results for 3 minutes = 2.106 and 1 hour = 2.051 therefore passed
- Acceptance criteria met for positive control: The mean of the positive control relative percentage viability, after 1hour exposure must be < 15% of the mean of the negative control. The result was a pass at 7.875
- Acceptance criteria met for variability between replicate measurements: should not exceed 0.3 (30%), result = pass.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The skin corrosion potential of Phenol, ethoxylated was tested. The tissue viability of the test item treated tissues were assessed and compared to a negative control. The percentage viability obtained after 3 minutes was 89.006% and after 60 minutes was 29.186%. The substance did not meet the criteria for classification as a corrosive in accordance with CLP Regulation (EC) No. 1272/2008.
Executive summary:

The skin corrosion potential of Phenol, ethoxylated was evaluated using OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method). The test was GLP-compliant. Triplicate EpiDermTM skin model tissues were treated with a single topical application of 50µl of Phenol ethoxylated. Additional triplicate tissues were treated with 50µl of Sterile Water (Negative control) and 50µl of Potassium Hydroxide (Positive control). All tissues were exposed for 30 minutes and 60 minutes at 37°C, 5% CO2, ≥95% Relative Humidity, prior to the MTT endpoint. Corrosion is directly related to cytotoxicity in the EpiDerm™ tissue. Cytotoxicity is demonstrated by the reduction of MTT (3-[4,5dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to formazan by viable cells in the test item treated tissues compared to the corresponding negative control. The results are then used to make a prediction of the corrosivity potential of the test item. All controls were valid and demonstrated the reliability of the test system. Mean tissue viability (as a percentage of the negative control), was 89.006% and 29.186 % after 3 and 60 minutes of exposure, respectively. Therefore, Phenol ethoxylated does not meet the criteria for classification according to CLP Regulation (EC) No. 1272/2008.