Vinyl 4-(1,1-dimethylethyl)benzoate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

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)

Version / remarks:

26. June 2020

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Vinyl 4-(1,1-dimethylethyl)benzoate

EC Number:

239-510-5

EC Name:

Vinyl 4-(1,1-dimethylethyl)benzoate

Cas Number:

15484-80-7

Molecular formula:

C13H16O2

IUPAC Name:

ethenyl 4-tert-butylbenzoate

Test material form:

liquid

Details on test material:

- Name: SAT 200028
- Batch No.: 19K2505
- Physical State: liquid
- Purity: 99.0%
- Expiry Date: 30 June 2021
- Storage Conditions: at room temperature, protected from light
- Safety Precautions: The routine hygienic procedures were sufficient to assure
personnel health and safety.

Test animals / tissue source

Species:

cattle

Details on test animals or tissues and environmental conditions:

The assay uses isolated corneas obtained as a by-product from animals freshly slaughtered at the abattoir Vion Beef B.V., Buchloe, Germany.
On the test day, fresh eyes were collected from the slaughterhouse and were transported in HBSS containing Pen/Strep on ice to the laboratories. Immediately after arrival of the eyes, cornea preparation was initiated.
The eyes were carefully examined for defects and any defective eyes were discarded.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

750 µL

Duration of treatment / exposure:

10 Min

Number of animals or in vitro replicates:

3

Details on study design:

Preparation of the Corneas
The tissue surrounding the eyeball was carefully pulled away and the cornea was excised leaving a 2 to 3 mm rim of sclera. The isolated corneas were stored in a petri dish containing HBSS. Before the corneas were mounted in corneal holders (Duratec GmbH) with the endothelial side against the O-ring of the posterior chamber, they had been visually examined for defects and any defective cornea had been discarded. The anterior chamber was then positioned on top of the cornea and tightened with screws. The chambers of the corneal holder were then filled with RPMI 1640 medium (without phenol red) containing 1% FBS and 2 mM L-glutamine (complete RPMI 1640 medium). The posterior chamber was always filled first. The corneas were incubated for one hour at 32 +/- 1 °C.


Calibration of the Opacitometer
The opacitometer (BASF-OP3.0, Duratec GmbH) was switched on at least 15 min before starting the calibration procedure. The filter holder was placed into the opacitometer and the readout was adjusted to 1000 ± 10 lux using the “Calibrate”-turning knob. For calibration the glass filter F2 was introduced into the filter holder. The readout lay in the range between 540-560 lux. To test the linearity of the measurement, two additional calibration filters, glass filter F3 and glass filter F4, were measured. For these glass filters, the opacitometer displayed values between 300-310 lux and between 90-100 lux. The calibration procedure was performed before the test and is documented in the raw data.


Treatment of the Corneas
After the equilibration period, the medium was removed from both chambers and replaced with fresh complete RPMI 1640 medium. An initial measurement was performed on each of the corneas using the opacitometer. Three corneas with illuminance readings approximately equivalent to the median illuminance of all corneas were selected as negative-control corneas. The illuminance of each cornea was read and recorded. Only corneas that had an initial illuminance reading I > I0/1.1651 lux were used for the assay. The medium was removed from the anterior chamber and replaced with the test item or control.
750 µL of the test substance or the control substance was introduced into the anterior chamber. After 10 minutes incubation at 32 +/- 1 °C either the test substance or the control substance was removed and the epithelium washed at least three times with MEM (containing phenol red). Once the medium was free of test substance, the cornea was finally rinsed with complete RPMI 1640 medium (without phenol red). The anterior chamber was refilled with complete RPMI 1640 medium and an illuminance measurement was performed after 2 hours incubation at 32 +/- 1 °C. Also, each cornea was observed visually and pertinent observations were recorded.
After the illuminance measurement was performed, the medium was removed from both chambers of the holder. The posterior chamber was refilled with fresh complete RPMI 1640 medium. 1 mL of a 4 mg/mL sodium fluorescein solution was added to the anterior chamber and the corneas were incubated for 90 minutes at 32 +/- 1 °C. Then the medium from the posterior chamber was removed and its optical density at 490 nm (OD490) was determined, using a spectrophotometer (Jenway 6405 UV/VIS).


Test Groups
3 corneas for the test item
3 corneas as negative controls treated with physiological saline 0.9% NaCl
3 corneas as positive control treated with ethanol 100%
The BCOP assay is considered to be valid if the in vitro irritation score obtained with the positive control falls within the two standard deviations of the current historical mean.
The negative control responses resulted in opacity and permeability values that are less than the established upper limits for background bovine corneas treated with the respective negative control.

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean

Value:

0.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

IVIS 2.39

Positive controls validity:

valid

Remarks:

IVIS 40.69

Remarks on result:

no indication of irritation

Any other information on results incl. tables

None of the corneas treated with SAT 200028 showed any opacity of the tissue.
The following mean in vitro irritation score was calculated: 0.90.
Therefore the test item was classified into UN GHS No Category.

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.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

According to the evaluation criteria the test item SAT 200028 is classified into UN GHS No Category.

Executive summary:

The eye irritancy potential of SAT 200028 was investigated in the bovine corneal opacity and permeability assay. Preparation of the test item: The test item was tested as provided by the sponsor.

Visual observation after treatment: None of the corneas treated with SAT 200028 showed any opacity of the tissue.

Mean in vitro irritation score: 0.90
Classification: UN GHS No Category

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 resulted in opacity and permeability values that are less than the established upper limits for background bovine corneas treated with the respective negative control.

Conclusion
According to the evaluation criteria the test item SAT 200028 is classified into UN GHS No Category.