[No public or meaningful name is available]

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January - May 2018

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

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Test material form:

liquid

Details on test material:

Storage: room temperature
Form: liquid
Colour: colorless to yellowish

Test animals / tissue source

Species:

other: Reconstructed human Cornea-like Epithelia

Details on test animals or tissues and environmental conditions:

- Description of the cell system used: 0.60 cm² Reconstructed human Cornea-like Epithelia [EpiOcular(TM) OCL-212-ver2.0, supplied by MatTek Corporation]

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Concentration: Undiluted 50 µL

Duration of treatment / exposure:

30 minutes at 37°C, 5% CO2, 95% humidity (standard culture conditions)

Duration of post- treatment incubation (in vitro):

- Post-exposure immersion period: 12 minutes at room temperature
- Post-exposure incubation period: 2 hours at standard culture conditions

Number of animals or in vitro replicates:

Test item, negative and positive controls were applied on duplicate tissues.

Details on study design:

MAIN TEST
- Pre-incubation of the tissues:
On the day of receipt, the tissues in their well shipping container were equilibrated at room temperature for 15 minutes. Then the inserts (filter + epithelium) were gently removed from the agarose while avoiding leaving agarose on the polycarbonate filter. They were placed in 6 wells culture plate which had been previously filled with 1 mL of 37°C pre-warmed assay medium and incubated during 20 hours and 34 minutes at standard culture conditions.
After the overnight incubation, the tissues were pre-wetted with 20 μL of Ca2+Mg2+Free-DPBS. The tissues were incubated at standard culture conditions for 30 minutes.
- Treatment and post-treatment incubation of the tissues:
The test item was applied, as supplied, at the dose of 50 μL, to 2 living PBS pre-treated RhCE (EpiOcular™ tissue model) during 30 minutes at 37°C, 5% CO2, 95% humidity (standard culture conditions). In the same experimental conditions, a positive control (Methyl acetate), and a negative control (distilled water) were used. The controls were applied, as supplied, at the dose of 50 µL, to the surface of 2 viable RhCE tissue replicates during 30 minutes at standard culture conditions.
After the treatment, the test item and control substances were carefully washed from the RhCE tissues by extensive rinsing with Ca2+Mg2+Free-DPBS. The rinsed tissues were checked for any colouration and noted for comparable colour with the negative control. This rinsing step was followed by a 12-minute post-exposure immersion period at room temperature in 5 mL of fresh medium to remove any test item absorbed into the tissue. The RhCE constructs were then incubated for a 2-hour post-exposure incubation at standard culture conditions in 1 mL of fresh medium at 37°C, 5% CO2.
- MTT viability assay:
Following the exposure to the test item, viability measurements are performed immediately after the post-exposure incubation period of the rinsed tissues in fresh medium. This period allows both for recovery from weak cytotoxic effects and for appearance of clear cytotoxic effects.
The RhCE tissue viability was measured by enzymatic conversion of the vital dye MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; Thiazolyl blue tetrazolium bromide; CAS No. 298-93-1] by the viable cells of the tissue into a blue MTT formazan salt that is quantitatively measured by Optical Density (OD) after extraction from tissues. The measured OD was proportional to the number of living cells.
The RhCE constructs were placed in 300 µL of a MTT solution at 1.0 mg/mL for 3 hours at standard culture conditions. The precipitated blue formazan product was then extracted from the tissues by placing each insert in 2 mL of isopropanol during 17 hours and 40 minutes at 6±3°C in the dark. The concentration of formazan was measured by determining the OD at 570 nm, just after dilution of the extractions in isopropanol (1:2). The OD measurement of formazan extracts at 570 nm was measured in triplicate samples using the ELx800 absorbance microplate reader (controlled every year and calibrated if necessary) supplied by BioTek and the validated software Gen5 ELISA V1.05.11 supplied by BioTek.

Results and discussion

In vitro

Results

Irritation parameter:

other: % tissu viability

Run / experiment:

main experiment (mean value)

Value:

2.64

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

The mean percent tissue viability of the RhCE replicates treated with the test item was 2.64% versus 17.72% in the positive control (Methyl acetate).

Any other information on results incl. tables

Table 7.3.2/1: Main test - Individual and mean corrected OD values and tissue viabilities for the test item, the negative and positive controls

 

	Tissue	OD	Mean OD/disc (#)	Mean OD/product	Viability %	Mean viability %	Difference of viability %
Negative control	1	1.128	1.054	1.041	101.25	100.00	2.50
		1.062
		0.971
	2	1.018	1.028		98.75
		1.054
		1.012
Positive control	3	0.204	0.193	0.185	18.54	17.72	1.63
		0.184
		0.189
	4	0.172	0.176		16.91
		0.175
		0.180
Test item	9	0.027	0.029	0.028	2.79	2.64	0.29
		0.029
		0.029
	10	0.027	0.026		2.50
		0.027
		0.024

#: mean of 3 values (triplicate of the same extract)

OD: optical density

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

In accordance with the Regulation EC No. 1272/2008, the test item has to be identified as potentially requiring classification and labeling according to UN GHS Category 2 or Category 1.

Executive summary:

In an OECD 492 study, the test item was applied, as supplied, at the dose of 50 µL, to 2 living DPBS pre-treated RhCE (EpiOcular^TMtissue model) during 30 minutes at 37°C, 5% CO₂, 95% humidity. The exposure period was followed by extensive rinsing with DPBS at room temperature, a 12 minutes post-exposure immersion period at room temperature and a 2 hours post-exposure incubation at standard culture conditions. The tissue viability was measured by performing an MTT assay.

 

 The mean percent tissue viability of the RhCE replicates treated with the test item was2.64%versus 17.72% in the positive control (Methyl acetate).

 

 

In accordance with the Regulation EC No. 1272/2008, the test item has to be identified as potentially requiring classification and labeling according to UN GHS Category 2 or Category 1.