Registration Dossier

Administrative data

Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2017-12-08 to 2018-02-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Version / remarks:
Adopted 28 July 2015
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
- Name: Ytterbium stabilized Zirconium and Hafnium Oxide
- EC No.: 945-888-9
- Batch No.: 7170502
- Physical state: solid
- Colour: white
- Purity: > 95%
- Expiry date: 26 October 2022
- Storage conditions: room temperature, in a tightly closed container in a dry place
Specific details on test material used for the study:
Name: Ytterbium stabilized Zirconium and Hafnium Oxide
EC No.: 945-888-9
Batch No.: 7170502
Physical State: solid
Colour: white
Purity: > 95%
Expiry Date: 26 October 2022
Storage conditions: room temperature, in a tightly closed container in a dry place

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Justification for test system used:
This test uses the EpiDerm™ reconstructed human epidermis model (MatTek) which consists of normal human epidermal keratinocytes (NHEK) and therefore represents in vitro the target organ of the species of interest and closely mimics the biochemical and physiological properties of the upper parts of the human skin, i.e. the epidermis.
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™-Standard Model (EPI-200™)
- Tissue batch number(s): 25867

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1 °C
- Temperature of post-treatment incubation (if applicable): 37 ± 1 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: 1
- Observable damage in the tissue due to washing: None

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 5 mg/mL
- Incubation time: 60 min
- Wavelength: 570 nm
- Filter bandwidth: +/- 30 nm

NUMBER OF REPLICATE TISSUES: 3 per dose group

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- Fresh tissues / killed tissues : Killed tissues
- N. of replicates : 2

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than equal to 50%
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL DPBS

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL 5% SDS solution
Duration of treatment / exposure:
60 min
Duration of post-treatment incubation (if applicable):
42 h
Number of replicates:
3 per dose group, 3 dose groups

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
Mean of three replicates
Value:
92.8
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
no indication of irritation
Other effects / acceptance of results:
- OTHER EFFECTS:
- Visible damage on test system: None
- Direct-MTT reduction: No reduction observed
- Colour interference with MTT: No interference observed


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

- The mean absolute OD570of the three negative control tissues was 0.8 and ≤ 2.8 (1.907)

- The mean relative tissue viability (% negative control) of the positive control was 20% (3.1%)

- Standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (0.2% - 5.3%)

Table 1: Mean Relative Tissue Viability for the test item

 

Negative Control

Positive Control

Test item

Mean Relative Tissue Viability [%]

100.0

3.1

92.8

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In this study under the given conditions the test item showed no irritant effects. The test item is therefore classified as “non-irritant” in accordance with UN GHS “No Category”.
Executive summary:

In a primary skin irritation study conducted according to the guideline OECD 439, 25 mg of Ytterbium stabilized Zirconium and Hafnium Oxide (Purity > 95 %) was topically applied to the EpiDerm tissue for 60 min followed by a 42 h post-incubation period. Irritant potential of the test item was predicted from the relative mean tissue viabilities obtained compared to the corresponding negative control tissues concurrently treated with DPBS. The controls confirmed the validity of the study. The mean relative tissue viability (% negative control) was observed to be > 50% (92.8%). Based on these results, the test item is classified as a non-irritant under the UN GHS Criteria.