5-methyl-1,3-oxazolidin-2-one

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD (2014a) Draft Proposal for a New Test Guideline: Reconstructed Human Cornea like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

5-methyl-1,3-oxazolidin-2-one

EC Number:

810-292-9

Cas Number:

1072-70-4

Molecular formula:

C4H7NO2

IUPAC Name:

5-methyl-1,3-oxazolidin-2-one

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): 5-methyl oxazolidin-2-one
- Physical state: liquid, colorless, clear
- Analytical purity: 98.0 area%
- Lot/batch No.: EWALD-00441

Test animals / tissue source

Species:

other: in vitro test

Strain:

other: in vitro test

Test system

Vehicle:

unchanged (no vehicle)

Details on study design:

BCOP Test:
Corneas free of defects (opacity, scratches, pigmentation etc.) were dissected with a 2 to 3 mm rim of sclera. Isolated corneas were mounted in cornea holders that consists of anterior and posterior chambers. Both chambers were filled to excess with pre-warmed Eagles’s MEM (without phenol red) and then equilibrated in a vertical position at about 32 °C for at least 1 hour.
After the equilibration period the medium in both chambers was replaced with fresh prewarmed medium and initial corneal opacity readings were taken for each cornea with an opacitometer. Any corneas that showed macroscopic tissue damage or an opacity value < 545 opacity units1 were discarded. The remaining corneas were then distributed into negative control, positive control and treatment groups. Each corneal holder was uniquely identified with a number on the chambers.
Application of the test substance and washing:
Each treatment group (test substance, NC and PC) consisted of 3 corneas. Before application, the medium in the anterior chamber was removed using a syringe. 750 μL of the undiluted liquid test substance was applied into the anterior chamber using a pipette. For the control tissues 750 μL of de-ionized water (negative control, NC) or 750 μL of 100% ethanol (positive control, PC), were applied into the anterior chamber using a pipette.
The corneas were incubated in a horizontal position at about 32 °C for approximately 10 minutes (liquids and surfactants). The test substance, NC and PC were then removed from the anterior chamber using a syringe and the epithelium was washed at least 3 times with Eagle’s MEM (containing phenol red) and once with Eagle’s MEM (without phenol red). Both chambers were then refilled with fresh Eagle’s MEM (without phenol red).
Post-exposure incubation for liquid test substances and surfactants:
The corneas were incubated for further 2 hours at about 32 °C. After the incubation period the medium was removed and both chambers were then refilled with fresh Eagle’s MEM.
Measurement of final corneal opacity:
Before measurement, each cornea was observed visually and observations were recorded. Final corneal opacity readings were taken for each cornea with an opacitometer.
Determination of permeability:
For determination of permeability the medium in the anterior chamber was replaced by 1 mL sodium fluorescein solution (4 mg/mL for liquid test substances and surfactants) and incubated for 90 ± 5 min in a horizontal position at about 32 °C. The amount of sodium fluorescein that permeated through the corneas into the posterior chamber was measured spectrophotometrically. Three aliquots per cornea were transferred to a 96-well microtiter plate and the optical density (OD490) was determined. An aliquot was diluted 1:5 in Eagle’MEM (without phenol red) and measured analogously (test substance, only).

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Value:

143.4

Remarks on result:

positive indication of irritation

In vivo

Results

Irritation parameter:

other: In Vitro Irritancy Score (IVIS)

Score:

143.4

Remarks on result:

other: in vitro test on isolated bovine cornea

Any other information on results incl. tables

Mean values for opacity, permeability and IVIS of the test substance, NC and PC

Test substance	Mean Opacity Value	Mean Permeability Value	Mean In Vitro Irritancy Score
15/0112-1	99.2	2.953	143.4
NC	0.0	0.002	0.0
PC	32.2	1.084	48.4

5-methyl oxazolidin-2-one the results derived with BCOP alone were sufficient for a final assessment. Therefore further testing in EpiOcular was waived.

Based on the observed results for the BCOP Test alone and applying the evaluation criteria it was concluded, that 5-methyl oxazolidin-2-one causes ocular corrosion or severe irritation under the test conditions chosen

IVIS	Prediction
≤3	no classification for eye irritation^1
> 3;≤55	no prediction can be made for eyeirritation, further testing with another suitable method is required^2
> 55	ocular corrosive or severe irritant

¹According to the current OECD Guideline 437 (adopted July 2013), this prediction is possible, however, not recommended by the test facility. If the IVIS obtained for the substance tested in this study fell within this range, this aspect is discussed in section 5.

²The test method according to the OECD test guideline 437 revised and adopted in 2013 does not allow for the evaluation of eye irritation. I.e., the result does not exclude an irritation potential of the test substance. For final assignment of a risk phrase at present, results from another study are needed.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria