Magnesium titanate

Eye irritation

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Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

read-across source

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

Eyes from adult cattle (typically 12 to 60 months old) were obtained from a local abattoir as a by-product from freshly slaughtered animals. The eyes were excised by an abattoir employee after slaughter, and were placed in Hanks’ Balanced Salt Solution (HBSS) supplemented with antibiotics (penicillin at 100 IU/mL and streptomycin at 100 μg/mL). They were transported to the test facility over ice packs on the same day of slaughter. The corneas were prepared immediately on arrival.

Vehicle:

physiological saline

Controls:

yes, concurrent vehicle

yes, concurrent positive control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.75 mL
- Concentration (if solution): 20% w/v solution in sodium chloride 0.9% w/v.

Duration of treatment / exposure:

240 minutes

Duration of post- treatment incubation (in vitro):

Not applicable

Number of animals or in vitro replicates:

Three corneas

Details on study design:

SELECTION AND PREPARATION OF CORNEAS
The medium from both chambers of each holder was replaced with fresh complete EMEM. A pre-treatment opacity reading was taken for each cornea using a calibrated opacitometer. Three corneas were randomly allocated to the negative control. Three corneas were also allocated to the test item and three corneas to the positive control item.

NUMBER OF REPLICATES
Triplicate

NEGATIVE CONTROL USED
Sodium chloride 0.9% w/v

POSITIVE CONTROL USED
Imidazole

APPLICATION DOSE AND EXPOSURE TIME
The EMEM was removed from the anterior chamber of the BCOP holder and 0.75 mL of the test item preparation or control items were applied to the appropriate corneas. The holders were gently tilted back and forth to ensure a uniform application of the item over the entire cornea. Each holder was incubated, anterior chamber uppermost, at 32 ± 1 ºC for 240 minutes.

POST-INCUBATION PERIOD: no.

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: At least three.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: A post-treatment opacity reading was taken and each cornea was visually observed.
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of microtiter plate reader (OD492)

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA: Decision criteria as indicated in the TG.

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean

Value:

18

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: The corneas treated with the test item were clear post treatment, with some test item remaining on the cornea.


ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The negative control gave opacity of ≤2.4 and permeability ≤0.072. The negative control acceptance criteria were therefore satisfied.
- Acceptance criteria met for positive control: The positive control In Vitro Irritancy Score was within the range of 65.1 to 123.3. The positive control acceptance criterion was therefore satisfied.

Interpretation of results:

GHS criteria not met

Conclusions:

Calcium Titanium Trioxide produced an IVIS of 0.8 during an in vitro eye irritation study. No prediction can be made in regards to its classification as irritant or damaging to the eye.

Executive summary:

An in vitro Bovine Corneal Opacity and Permeability (BCOP) assay was performed in line with OECD Testing Guideline 437 (Bovine Corneal Opacity and Permeability Test Method). The study was GLP-compliant.

A solution of 20% w/v test material in sodium chloride 0.9% w/v was applied to three cattle corneas obtained from an abattoir at a volume of 0.75 mL, after which each cornea was incubated at 32±1°C for 240 minutes. Opacity and permeability of corneas were measured following exposition.

Negative and positive controls were performed and considered as valid.

An In Vitro Irritation Score (IVIS) of 18.0 was calculated for Calcium Titanium Trioxide from corneal opacity and permeability measurements. The substance is not irritant to the eye according to the guideline.

Since the result is between 3 and 55 no prediction can be made regarding the classification of Calcium Titanium Trioxide as irritant or damaging to the eye in accordance with with Regulation (EC) No.1272/2008.

Cross-reference 2

Reason / purpose for cross-reference:

read-across source

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From 19 July 2018 to 2 August 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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)

Deviations:

no

Remarks:

No deviation impacting on the quality of the study

GLP compliance:

yes (incl. QA statement)

Species:

hamster

Strain:

other: Reconstructed human Cornea-like Epithelium

Details on test animals or tissues and environmental conditions:

The EpiOcularTM tissue model is composed of stratified human keratinocytes in a three-dimensional structure, reflecting the morphology and function of the human corneal epithelium found in vivo

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): ca. 50 mg

Duration of treatment / exposure:

Application for 6 hours ± 15 minutes

Duration of post- treatment incubation (in vitro):

25 minutes ± 2 minutes post-treatment immersion, and 18 hours ± 15 minutes post-treatment incubation

Number of animals or in vitro replicates:

Three replicates

Details on study design:

Preliminary test

The test item is first checked for its potential for MTT interference and solvent interference (water and isopropanol).

Main test overview

Day 0: On the day of receipt, EpiOcular tissues were pre-incubated overnight at 37°C, 5%
CO2, ≥95% RH.

Day 1: Exposure to, and removal of 50 mg of test item using a dosing spoon or 50µl of reference items for 6 hours ± 15 minutes, followed by a 25 minutes ± 2 minutes post-treatment immersion, and 18 hours ± 15 minutes post-treatment incubation.

Day 2: End of MTT viability test, optical density readings at 570 nm without reference filter

Irritation parameter:

other: viability

Remarks:

in %

Run / experiment:

Mean of three replicates

Value:

86.657

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Name	Code	Mean of OD	SD of OD	Mean of viability (%)	SD of viability (%)	CV %	Corrected Mean of viability (%)	Classification
Sterile water	NC	1.839	0.039	100.000	2.11	2.115	N/A	No-Category
Methyl Acetate	PC	0.668	0.262	36.312	14.243	39.225	N/A	No Prediction
Calcium Titanium Trioxide	TA1	1.594	0.138	86.661	7.497	8.650	86.657%	No-Category

Interpretation of results:

GHS criteria not met

Conclusions:

The percentage viability of Calcium Titanium Trioxide was 86.657%. It was concluded that the substance did not require a classification as irritant or damaging to eye in accordance with Regulation (EC) No.1272/2008.

Executive summary:

A Reconstructed human Cornea-like Epithelium (RhCE) test for identifying chemicals not requiring classification and labelling for eye irritation or serious eye damage was performed on Calcium Titanium Trioxide in accordance with the OECD Testing Guideline 492. The study was GLP-compliant.

After 6 hours ± 15 minutes exposure on the surface of EpiOcular reconstructed ocular epithelium and 18 hours ± 15 mins post-incubation time, the viability of the tissues was assessed and compared to a negative control. The percentage viability of Calcium Titanium Trioxide was determined to be 86.657%. All acceptance criteria were met during the study.

According to the OECD Testing Guideline 492 A test item is considered as "No Category" (not requiring classification under Regulation (EC) No.1272/2008), if the eye model viability after exposure and post-treatment incubation is >60%. It can therefore be concluded that Calcium Titanium Trioxide does not meet the criteria for classification as irritant or damaging to the eye.

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Magnesium titanate

EC Number:

234-766-4

EC Name:

Magnesium titanate

Cas Number:

12032-30-3

Molecular formula:

Mg.O3Ti

IUPAC Name:

magnesium titanate

Test animals / tissue source

Species:

cattle

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Remarks on result:

no indication of irritation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The percentage viability of Magnesium Titanium Trioxide was 86.657%. It was concluded that the substance did not require a classification as irritant or damaging to eye in accordance with Regulation (EC) No.1272/2008. No prediction can be made in regards to its classification as irritant or damaging to the eye.