(tert-butoxymethyl)oxirane

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-11-30 to

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

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)

Version / remarks:

adopted October 2017

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU method B.47 (Bovine corneal opacity and permeability test method for identifying ocular corrosives and severe irritants)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

(tert-butoxymethyl)oxirane

EC Number:

231-640-0

EC Name:

(tert-butoxymethyl)oxirane

Cas Number:

7665-72-7

Molecular formula:

C7H14O2

IUPAC Name:

2-[(tert-butoxy)methyl]oxirane

Specific details on test material used for the study:

- Name in the test report: tert-Butyl glycidyl ether
- Homogeneity: homogeneous
- Appearance: clear, colourless liquid

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Bactch no. ZMG-195668
- Expiration date of the lot/batch: 2019-09-28

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Fridge (2 - 8 °C), keep container tightly closed in a dry, cool and well-ventilated place, keep cool and protect from sunlight

Test animals / tissue source

Species:

cattle

Strain:

other: Bos primigenius Taurus

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Müller Fleisch GmbH, Enzstr. 2-4, 75217 Birkenfeld, Germany
- Age: 12 - 60 months
- Transport conditions of ocular tissue (e.g. transport time, transport media and temperature, and other conditions): Transport media: The exes were transported in Hank's balanced salt solution with 1 % Penicillin-Streptomycin solution (Penicillin 100 U/mL, Streptomycin 100 µg/mL) in a suitable cooled container.
- Time interval prior to initiating testing: 1 h incubation at 32 + / - 1 °C
- indication of any existing defects or lesions in ocular tissue samples: No
- Indication of any antibiotics used: Not specified

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

other: negative control: Hank’s Balanced Salt Solution

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 750 µL
- Concentration (if solution): undiluted

Duration of treatment / exposure:

10 min

Duration of post- treatment incubation (in vitro):

2 h

Number of animals or in vitro replicates:

3 per test group. 3 test groups

Details on study design:

SELECTION AND PREPARATION OF CORNEAS : After having carefully cleaned and sterilised the cornea holders, corneas were kept in the incubation chamber at 32 + / - 1 °C. On the day of the assay, the MEM without phenol red was supplemented with sodium bicarbonate, L-glutamine and 1% fetal calf serum (= complete MEM) and stored in a water bath at 32 + / - 1 °C. The same was performed with the MEM with phenol red, but without addition of sodium bicarbonate. After the arrival of the corneas, they were examined and only corneas which were free from damages were used. The corneas were excised with a scalpel and cut from the globe with a 2-3 mm ring of sclera around the outside. Each cornea was transferred to a cornea holder in which pre-warmed cMEM (32 + / - 1 °C) without phenol red was filled. The holders were then incubated for 1 hour in the incubation chamber at 32 + / - 1 °C.

NUMBER OF REPLICATES : 3

NEGATIVE CONTROL USED : Hank’s Balanced Salt Solution (HBSS) 10-fold concentrated, diluted in de-min. water (1:10)

POSITIVE CONTROL USED : Dimethylformamide (DMF)

EXPOSURE TIME : 10 min

TREATMENT METHOD: [closed chamber / open chamber] : Closed chamber

POST-INCUBATION PERIOD: yes/no. : Yes, 2 h

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: 2
- POST-EXPOSURE INCUBATION: 2 h

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: change of opacity value of each treated cornea was calculated
- Corneal permeability: measured as optical density of the liquid with a microtiter plate photometer at 492 nm.

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA:
- IVIS ≤ 3: UN GHS No Category
- IVIS > 3 to ≤ 55: No prediction can be made
- IVIS > 55: UN GHS Category 1

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean of three replicates: First experiment

Value:

56.3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: equivocal, because two of the three replicates gave discordant predictions from the mean value

Results 2

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean of three replicates: Second experiment

Value:

59

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:

OTHER EFFECTS:
- Visible damage on test system: No

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes

For individual results see Tables 1 &2 in box 'Any other information on results incl. tables'.

Any other information on results incl. tables

Table 1: IVIS values of the first experiment

Test group	IVIS	Mean IVIS	Relative standard deviation IVIS
Negative control HBSS	0.09	0.71	132.40 %
	1.80
	0.25
Test item tert-Butyl glycidyl ether	51.80	56.30	11.78 %
	53.18
	63.92
Positive control DMF undiluted	92.64	90.87	12.14 %
	100.91
	79.06

Table 2: IVIS values of the second experiment

Test group	IVIS	Mean IVIS	Relative standard deviation IVIS
Negative control HBSS	1.79	1.83	29.79 %
	2.40
	1.31
Test item tert-Butyl glycidyl ether	56.73	59.00	7.14 %
	63.86
	56.41
Positive control DMF undiluted	106.74	84.85	22.43 %
	75.55
	72.26

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

In conclusion, based on the mean in vitro irritation score of 59 obtained in the bovine corneal opacity and permeability assay (BCOP, OECD 437), the test substance needs to be classified as Eye Dam. 1 (H318) in accordance with Regulation (EC) No 1272/2008 (CLP).

Executive summary:

The eye irritancy potential of the test item was investigated in the bovine corneal opacity and permeability assay (OECD 437). The test item was incubated on the cornea for 10 minutes at 32 + / - 1 °C. After removal of the test item and 2 hours post-incubation, opacity and permeability values were measured. All three corneas treated with the test item showed strong opacity of the tissue. The mean in vitro irritation score in the first and second experiment were 56.3 and 59 respectively. The in vitro irritation score obtained with the positive control fell within the two standard deviations of the current historical mean and therefore this assay is considered to be valid. The negative control responses should result in opacity and permeability values that are less than the established upper limits for background bovine corneas treated with the respective negative control. Based on the results obtained the test substance has to be classified as Eye Dam. 1 (H318) in accordance with Regulation (EC) No 1272/2008 (CLP).