3-[[5-methyl-2-(1-methylethyl)cyclohexyl]oxy]propane-1,2-diol

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 January 2017 - 02 February 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Compliant to GLP and testing guidelines; adequate consistence between data, comments and conclusions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EU method B.47 (In vitro eye irritation)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD guideline 437 (In vitro eye irritation)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-[[5-methyl-2-(1-methylethyl)cyclohexyl]oxy]propane-1,2-diol

EC Number:

289-296-2

EC Name:

3-[[5-methyl-2-(1-methylethyl)cyclohexyl]oxy]propane-1,2-diol

Cas Number:

87061-04-9

Molecular formula:

C13H26O3

IUPAC Name:

3-{[5-methyl-2-(propan-2-yl)cyclohexyl]oxy}propane-1,2-diol

Test material form:

liquid

Test animals / tissue source

Species:

other: bovine cornea

Strain:

other: not applicable

Details on test animals or tissues and environmental conditions:

Species: bovine cattle.
Origin: bovine eyes were obtained from freshly slaughtered cattle at the abattoir EVA, Saint Pierre sur Dives, France.
Age: as French Authorities avoid the use of any organs from the head of bovines aged more than 12 months, bovine cattle were up to 12 months old (typically, 5 to 8 months old).
Reason for choice: bovine corneas are recommended by Regulatory Authorities for this type of study. They are adapted for the evaluation of potential ocular irritants since they are part of the target organ.
Transport from Supplier to CiToxLAB France: the eyes were transported to CiToxLAB France at ambient temperature, immerged in buffered Hanks medium containing an antibiotic [Hank’s Balanced Salts Solution (HBSS) plus penicillin/streptomycin (100 units/100 µg/mL final)]. A container with smooth internal surfaces was used for the transport to avoid damage to the corneas.
Upon arrival at CiToxLAB France, the selection and preparation of corneas was performed as soon as possible. At each step of the preparation procedure, care was taken to avoid touching the corneas in order not to damage them.

Selection: a careful macroscopic examination was performed on all eyes to detect the presence of any defects (opacity, scratches, pigmentation, etc). Any eyes with defects were discarded. The examination was performed under a lamp, using HBSS in order to keep the eyes moistened and shiny. Particular attention was paid to the corneas and the eyes were swivelled in order to observe the fringe areas and any scratches directly under the light.
Preparation of the selected corneas: the tissues surrounding the eyeball were carefully pulled away and the cornea, surrounded by approximately 2 to 3 mm of sclera, was dissected out. The isolated corneas were stored in HBSS until all corneas had been prepared.
Washing of the corneas: the corneas were washed for 15 minutes, three times, in HBSS plus penicillin/streptomycin (100 units/100 µg/mL final) at room temperature. The corneas were used within a maximum of 24 hours.
Storage of the corneas: as the corneas were not used immediately, they were stored after washing. Each cornea was stored individually in 12 mL of M199 medium containing 5% dextran, plus penicillin/streptomycin, at +4°C, for a maximum of 24 hours before use.

(Pre)Incubation T°C: 32°C
Dates of experimental phase: from 30 January 2017 to 02 February 2017.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: in vitro negative and positive controls

Amount / concentration applied:

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

VEHICLE
- Amount(s) applied (volume or weight with unit): not applicable
- Concentration (if solution): not applicable
- Lot/batch no. (if required): not applicable
- Purity: not applicable.

Duration of treatment / exposure:

Exposure period of 10 minutes (+/- 30 seconds), followed by rinsing.

Observation period (in vivo):

Opacity measurement:
- before treatment
- after 2-hour incubation in water

Permeability measurement:
- after 90-min incubation in water (and other procedures), following the 2nd opacity measurement

Number of animals or in vitro replicates:

Not applicable
Triplicate corneas for each timepoint and tested substance (test item, negative control, positive control)

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Rinsing: the anterior part of the eye was emptied and then rinsed 7 times with pre-warmed cMEM containing phenol red. Despite the rinsing performed, residual test item was noted over each treated cornea.
NEGATIVE CONTROL:
As the test item was tested undiluted (i.e. in its original form), 0.9% Sodium Chloride (0.9% NaCl) was used as negative control.
Since several test items were assayed concurrently, the negative control was shared.

POSITIVE CONTROL:
As the test item was tested using a 10-minute treatment, the positive control was Absolute Ethanol. It was used neat and sampled on the day of use.
Since several test items were assayed concurrently, the positive control was shared.

SCORING SYSTEM/TOOL
- Opacity:
Using an opacitometer
The average change in opacity during exposure is determined. It is corrected by subtracting the average negative control value from values in positive control and test item.
- Permeability:
Using a spectrophotometer: optical density (OD) at 490 nm wavelength
The optical density is corrected by subtracting the average negative control value from values in positive control and test item.
- Scoring:
In vitro irritancy score (IVIS) = Corrected Opacity + (15 x Corrected OD)

Interpretation: see below

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Value:

77

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

The test item was identified as a test chemical inducing serious eye damage (UN GHS Category 1).

Executive summary:

The objective of this study was to evaluate the potential irritant and corrosive properties of the test item, COOLACT 10, to the eye. The Bovine Corneal Opacity and Permeability (BCOP) test method can identify chemicals inducing serious eye damage and chemicals not requiring classification for eye irritation or serious eye damage.

The design of this study was based on the guideline OECD Guideline 437 and the study was performedin compliance with CiToxLAB France standard operating procedures and with the OECD Principles of Good Laboratory Practice.

 

Method

Corneas obtained from freshly slaughtered calves were mounted in corneal holders. Both chambers of the corneal holder were filled with complemented MEM culture media (cMEM) and pre-incubated for 1 hour and 5 minutes (± 5 minutes) at +32°C.

A single experiment was performed using three corneas for each treated series (test item, positive and negative controls).

Before the treatment, a first opacity measurement was performed on each cornea using an opacitometer.

The test item was applied undiluted, in a single experiment using a treatment time of 10 minutes and using the open-chamber method. Negative and positive controls were applied using the same treatment time and using the closed-chamber method. At the completion of the treatment period, all items were removed from the front opening of the anterior chamber and the epithelia were rinsed.

The corneas were then incubated for 2 hours (± 10 minutes) at +32°C before a second opacity measurement was performed.

After the second opacity measurement, the medium of the anterior chamber was removed and filled with a fluorescein solution. The holders were then incubated vertically for 90 minutes (± 5 minutes) at +32°C.

At the end of the incubation period, the optical density of the solution from the posterior chamber of each holder was measured in order to determine the permeability of the cornea. Each cornea was then observed for opaque spots and other irregularities.

 

Results

Macroscopic examination

Opacity and fluorescein fixation were observed on the corneas treated with the test item.

 

In Vitro Irritancy Score

All acceptance criteria were fulfilled. The study was therefore considered as valid.

The mean In Vitro Irritancy Score (IVIS) of the test item-treated corneas was: 77.

 

As the mean IVIS was > 55, the test item was considered asa testchemicalinducing serious eye damage (UN GHS Category 1).

Conclusion

Under the experimental conditions of this study, the test item was identified asinducing serious eye damage (UN GHS Category 1).