2,3-difluoro-1-propoxy-4-[4-(trans-4-propylcyclohexyl)-1-cyclohexen-1-yl]-benzene

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 27, 2017 - January 31, 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

Test guideline 1

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)

Version / remarks:

July 28, 2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: DB-ALM Protocol No. 164: Ocular Irritation Assay for Chemicals using EpiOcular™ EIT,

Version / remarks:

September 14, 2015

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EpiOcular Eye Irritation Test (OCL-200-EIT) for the prediction of acute ocular irritation of chemicals; For use with MatTek Corporation`s Reconstructed Human EpiOcular Model; MatTek Corporation

Version / remarks:

June 29, 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,3-difluoro-1-propoxy-4-{4-[(1s,4r)-4-propylcyclohexyl]cyclohex-1-en-1-yl}benzene

EC Number:

600-065-0

Cas Number:

1003218-40-3

Molecular formula:

C24H34F2O

IUPAC Name:

2,3-difluoro-1-propoxy-4-{4-[(1s,4r)-4-propylcyclohexyl]cyclohex-1-en-1-yl}benzene

Specific details on test material used for the study:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: No pre-treatment, the test item was applied neat to the tissues.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL: 50 mg per tissue

NEGATIVE / VEHICLE CONTROL: 50 µL per tissue

Sterile deionized water was used as negative control.

POSITIVE CONTROL: 50 µL per tissue

Designation: Methyl acetate
Supplier: MatTek In Vitro Life Science Laboratories
Lot-No.: 032817ISA
Catalog #: TC-MA
Purity (GC): 99.7%
Appearance: Colorless liquid
Expiration date: March 28, 2018
Storage: 15 to 30°C

Duration of treatment / exposure:

6 hours

Number of animals or in vitro replicates:

in vitro: duplicate design

Details on study design:

Controls
Negative/Vehicle Control: Sterile deionized water

Positive Control: Methyl acetate, MatTek In Vitro Life Science Laboratories, Lot-No 032817ISA, Expiration date March 28, 2018

Number of Replicates
The test item as well as the positive and negative control were tested in batch-duplicates. Therefore, a total number of six tissues was used in this study.

Preparation
On day of receipt, the tissues were equilibrated in their 24-well shipping container to room temperature for about 15 minutes. Afterwards the tissues were removed from the shipping container using sterile forceps and transferred to 6-well plates containing 1 mL pre-warmed (37°C) assay medium. Any agarose adhering to the inserts was removed by gentle blotting on gauze or paper towel. Afterwards, the tissues were incubated at 37°C and 5% CO2 overnight (16-24 hours) without medium exchange.

Pre-Treatment
After the overnight incubation, the tissues were pre-wetted with 20 µL DPBS and incubated at 37°C and 5% CO2 for 30 minutes (± 2 minutes).

Treatment
After the 30 minute DPBS pre-treatment, the negative and the positive control were tested by applying 50 µL topically on the EpiOcular tissues. The solid test item was tested by evenly applying 50 mg topically on the EpiOcular tissues. The tissues were placed back into the culture medium after dosing and incubated at 37°C and 5% CO2 for 6 hours (± 15 minutes).

At the end of the 6 hours treatment time, the positive control, negative control and the test item were removed by extensively rinsing the tissues with pre-warmed (room temperature) DPBS. Three clean beakers, containing a minimum of 100 mL each of DPBS were used per group. The inserts containing the tissue were lifted out of the medium by grasping the upper edge of the plastic "collar" with fine forceps. To assure throughput, the two tissues per group were rinsed simultaneously by holding the replicate inserts together by their collars using forceps. The test item or control articles were decanted from the tissue surface onto a clean absorbent material and the cultures dipped into the first beaker of DPBS, swirled in a circular motion in the liquid for approximately 2 seconds, lifted out so that the inserts were mostly filled with DPBS, and the liquid was decanted back into the container. This process was performed at least two additional times in the first beaker. The culture was then rinsed in the second and third beakers of DPBS at least three times each in the same fashion. Finally, any remaining liquid as decanted onto the absorbent material.

After rinsing, the tissues were immediately transferred in 5 mL of pre-warmed (room temperature) assay medium in a 12-well plate for 25 minutes (± 2 minutes) at room temperature.

Post-Treatment Incubation
After the 25 minutes incubation, each insert was removed from the assay medium, the medium was decanted off the tissue, and the insert were blotted on absorbent material and transferred in 6-well plates filled with 1 mL of pre-warmed (37°C) assay medium for 18 hours (± 15 minutes) at 37°C and 5% CO2.

MTT-Assay
After the post-treatment incubation period, the treated tissues were transferred in a 24-well plate filled with 300 µL MTT solution (1.0 mg/mL MTT). Once all the tissues were placed into the 24-well plate, the plate was incubated for 180 minutes (± 10 minutes) at 37°C and 5% CO2.

The inserts were removed from the 24-well plate after 180 minutes (± 10 minutes). The bottom of the inserts was blotted on absorbent material, and then transferred to a 6-well plate containing 2 ml isopropanol so that no isopropanol was flowing into the inserts. The plate was sealed with a standard plate sealer. To extract the MTT, the plates was placed on an orbital plate shaker and shaken for 2 to 3 hours at room temperature. The corresponding negative and positive controls were treated identically.

The extract solution was mixed and 2 x 200 µL were transferred into a 96-well plate.The OD was read using a spectrophotometer at 570 nm wavelength.A functional test of the microplate reader was performed using a filter test plate. The results of the functional test and the printout of the measurement were included in the raw data of the study.

Evaluation of Results
All formulas for the calculation of the relative viability were given by the supplier of the human in vitro eye model (MatTek In Vitro Life Science Laboratories).
The calculation was performed with the MS-Excel-Sheet “InVitroEyeIrritation_V01”. The mean OD (optical density) of the two negative control tissues as calculated. This value corresponds to 100% tissue viability in the current test. For each individual tissue treated with the test item or the positive control the individual relative tissue viability was calculated according to the following formula:

Viabililty (%) = (test item OD/mean negative control OD) x 100

If the test item-treated tissue viability is >60.0% relative to negative control-treated tissue viability, the test item is labeled non-irritant (UN GHS No Category).

If the test item-treated tissue viability is <=60.0% relative to negative control-treated tissue viability, the test item is labeled irritant (UN GHS Category 1 or Category 2).


Acceptance Criteria
The results are acceptable if:

The negative control OD >0.8 and <2.5

The mean relative viability of the positive control is:
a) 30 minute exposure: below 50% of control viability
b) 6 hour exposure: below 50% of control viability

The difference of viability between the two relating tissues of a single chemical is <20% in the same run (for positive and negative control tissues and tissues of single chemicals). This applies also to the killed controls (single chemicals and negative killed control) and the colorant controls which are calculated as percent values related to the viability of the relating negative control.

Results and discussion

In vitro

Results

Irritation parameter:

other: Viability %

Run / experiment:

Run 1 / Experiment 1

Value:

97.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: No observations

ACCEPTANCE OF RESULTS:
1. The negative control OD is >0.8 and <2.5 (1.403 and 1.615).
2. The mean relative viability of the positive control is below 50% of the negative control viability (47.0%).
3. The difference of viability between the two relating tissues of a single chemical is <20% (values between 1.1% to 14.0%) in the same run (for positive and negative control tissues and tissues of single chemicals).

The study met all acceptance criteria

Any other information on results incl. tables

	Mean OD	Mean Viability
Negative Control	1.509	100.0%
Positive Control	0.709	47.0%
Test Item	1.475	97.8%

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the present study, the test item did not show an eye hazard potential. The test item is labeled non-irritant (UN GHS: No Category).

Executive summary:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 492.The objective was to investigate the potential of the test item to induce eye irritation in an in vitro human cornea model.The test item was applied topically to a reconstructed human cornea-like epithelium model (EpiOcular) followed by determination of the cell viability. Cell viability was determined by enzymatic conversion of vital dye MTT into a blue formazan salt and measurement of the formazan salt after extraction from tissues. The percent reduction of cell viability in comparison to untreated negative controls was used to predict the eye irritation potential. Duplicates of the EpiOcular-model were treated with the test item, the negative or the positive control for 6 hours (± 15 minutes). 50 mg of the test item and 50 µL of either the negative control (sterile deionized water) or the positive control (methyl acetate) were applied to the tissues.

After treatment with the negative control (sterile deionized water) the mean OD was 1.509 (study acceptance criterion: >0.8 and <2.5). Treatment with the positive control (methyl acetate) revealed a mean viability value of 47.0% (study acceptance criterion: <50%). Thus, the acceptance criteria were met.

Following treatment with the test item, the tissue viability was 97.8% and, thus, higher than 60%, i.e.according to OECD 492 the test item is labeled non-irritant (UN GHS: No Category).

Under the conditions of the present study, the test item did not show an eye hazard potential. The test item is labeled non-irritant (UN GHS: No Category).