Neodymium trihydroxide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 January 2017 to 20 January 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 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

Version / remarks:

adopted 28 July 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Neodymium trihydroxide

EC Number:

240-514-4

EC Name:

Neodymium trihydroxide

Cas Number:

16469-17-3

Molecular formula:

H3NdO3

IUPAC Name:

neodymium trihydroxide

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study report): neodymium trihydroxide
- Physical state: solid
- Appearance: clear blue powder (purple under UV light)

Specific details on test material used for the study:

- correction factor: no correction factor is applied for this type of study

Test animals / tissue source

Species:

human

Strain:

other: Reconstructed human cornea-like epithelium (tissues)

Details on test animals or tissues and environmental conditions:

TEST SYSTEM
- Source: MatTek, Bratislava, Slovak Republic
- Expiry date: The EpiOcularTM tissues were used within 72 hours of their production.
- Selection: At receipt, the tissues were inspected for obvious defects as they could have been rejected based on blistering, excess fluid or air bubbles below the tissue insert. Cultures with air bubbles under the insert covering greater than 50% of the insert area were not used.
- Storage conditions: At receipt, the living EpiOcularTM tissues were stored on their day of arrival.
- Description of the cell system used: EpiOcularTM living tissue consists of an airlifted, living, multilayered ocular tissue construction (surface 0.6 m2), reconstructed from normal (non-transformed) human-derived keratinocytes. This is a non-keratinized epithelium which models the corneal epithelium with progressively stratified, but not cornified cells. The cells are cultured in proprietary serum-free culture media, which induces corneal differentiation and the formation of the organotype 3D cornea-like model. The 3D tissue consists of highly organized cell layers similar to that found in the cornea. The model features a normal ultra-structure and is functionally equivalent to human in vivo tissue.
- Justification of the test method and considerations regarding applicability: The study was performed in a tier 2 strategy since the ocular corrosive or severe irritant potential of the test item could not be predicted in a tier 1 BCOP test (CiToxLAB France/Study No. 44478/TIB). The Epiocular Eye Irritation Test (EIT) protocol is particularly relevant for testing neat/non-diluted chemicals.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 51 mg
- Preparation: As the test item was a solid, the required quantity was weighed before treatment and was stored at room temperature and protected from humidity until application.
- Administration: The quantity of 51 mg +/- 1 mg was applied evenly to the surface of each tissue, taking care to spread it over the whole tissue surface area without damaging the tissue sample.

Duration of treatment / exposure:

6 hours

Observation period (in vivo):

Not applicable

Duration of post- treatment incubation (in vitro):

18 hours

Number of animals or in vitro replicates:

2

Details on study design:

Details of the test procedure used:
- RhCE tissue construct used, including batch number: EpiOcular tissue, MatTek, Bratislava, Slovak Republic
- Doses of test chemical and control substances used: 51 mg of test item, 50 µL of deinonized water for negative control, 50 µL methyl acetate for positive control.
- Duration and temperature of exposure, post-exposure immersion and post-exposure incubation periods (where applicable): 6 hours at 37°C, soaked in assay medium 25 minutes at room temperature, blotted, and then incubated for 18 hours at 37°C, 5% CO2.
- Indication of controls used for direct MTT-reducers and/or colouring test chemicals (if applicable): yes. No coloring potential found; no additional controls needed.
- Number of tissue replicates used per test chemical and controls (positive control, negative control): 2 - Wavelength and band pass (if applicable) used for quantifying MTT formazan, and linearity range of measuring device: 570 nm plate reader
- Description of the method used to quantify MTT formazan: Following incubation, tissues were transferred to new well plates with 0.3 mL freshly prepared MTT solution and incubated for 3 hours at 37°C, 5% CO2.
- Acceptable variability between tissue replicates for positive and negative controls: Negative control acceptance criteria - Mean cOD between 0.8 and 2.5. Positive control - Relative mean viability of the positive control is < 50% of the relative mean viability of the negative control.
- Acceptable variability between tissue replicates for the test chemical: Acceptable if the difference of viability between the two tissue replicates is < 20%.

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

other: Optical density measurement

Run / experiment:

Mean of two replicates

Value:

1.604

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

other: Relative viability in %

Run / experiment:

Mean of duplicate tissues

Value:

103

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- All test item-treated tissues appeared blue (with a white spot for one of the treated tissues) which was considered indicative for viable tissues.
- All of acceptance criteria for the negative and positive controls were fulfilled, therefore the study was considered to be valid.
- As the mean viability was > 60% after the MTT reduction, the results met the criteria for a non-irritant response.

OTHER EFFECTS:
- Visible damage on test system: No

DEMONSTRATION OF TECHNICAL PROFICIENCY: Not specified

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes
- Range of historical values if different from the ones specified in the test guideline: Not specified

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions of this study, the test item is considered to be non-irritant to Reconstructed human Cornea-like Epithelium.
According to the results of this study, the classification of the test item should be: No Category (GHS 2015 and Regulation (EC) No. 1272/2008).