[3R-(3α,3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

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)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

[3R-(3α,3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol

EC Number:

201-035-6

EC Name:

[3R-(3α,3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol

Cas Number:

77-53-2

Molecular formula:

C15H26O

IUPAC Name:

[3R-(3α,3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol

Test material form:

solid: particulate/powder

Test animals / tissue source

Species:

other: Bos primigenius Taurus (fresh bovine corneas)

Details on test animals or tissues and environmental conditions:

Fresh bovine eyes were obtained from the slaughterhouse Müller Fleisch GmbH, Enzstr. 2-4, 75217 Birkenfeld, Germany, on the day of the test. The cattle were between 12 and 60 months old. The eyes were transported to the test facility in Hanks’ Balanced Salt Solution with 1% Penicillin-Streptomycin solution (Penicillin 100 U/mL, Streptomycin 100 µg/mL) in a suitable cooled container within 1 hour.

Test system

Vehicle:

Hank's balanced salt solution

Controls:

yes, concurrent positive control

yes, concurrent negative control

Duration of treatment / exposure:

Exposure time on the corneas was 4 hours at 32 ± 1 °C

Number of animals or in vitro replicates:

3

Details on study design:

After the initial incubation, the medium was changed and the baseline opacity for each cornea was recorded. None of the corneas showed tissue damage; therefore, all corneas were used. For each treatment group (negative control solution, test item and positive control solution), three replicates were used. After removal of the pre-incubation medium (cMEM without phenol red), 750 µL negative control solution, a defined amount of test item (see table 7.3-a) and 750 µL positive control solution were applied to each replicate.
According to the characteristics of the test item, the following treatment procedure was performed:
1. Open Chamber Method
In order to apply the test item, the nut was unscrewed to remove the glass disc. Then, the test item could be applied directly on the cornea.
The following amounts of the test item were tested neat and applied directly on the cornea using a weighing funnel:
Table a Amounts of Test Item
Replicate Amount
1 206.6 mg
2 216.9 mg
3 211.8 mg
The test item was given on the epithelium in such a manner that the cornea was completely covered with test item.

Exposure time on the corneas was 4 hours at 32 ± 1 °C. After thorough rinsing with cMEM with phenol red and final rinsing with cMEM without phenol red, both chambers were filled with cMEM without phenol red, and the final opacity value of each cornea was recorded.

2. Permeability Test
After the recording of the final opacity value, the cMEM without phenol red was removed from the front chamber, and 1 mL sodium fluorescein solution was added to the front chamber for the detection of permeability of the corneas.
For the open chamber method, a sodium fluorescein solution with a concentration of 5 mg/mL was used.
The chambers were then closed again and incubated for 90 minutes at 32 ± 1 °C. After incubation, the content of the posterior chamber was thoroughly mixed. Then, its optical density at 492 nm was measured with the microtiter plate photometer.

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Value:

0.92

Negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the test item[3R-(3α, 3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol(Cedrol)showed no effects on the cornea of the bovine eye. The calculated mean IVIS was 1.30.
According to OECD Guideline no. 437 (Oct. 2017), a substance with an IVIS ≤ 3 requires no classification for eye irritation or serious eye damage.

Executive summary:

One valid experiment was performed.

Bovine corneas were used. They were collected from slaughtered cattle that were between 12 and 60 months old.

The test item[3R-(3α, 3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol (Cedrol)was applied onto the cornea of a bovine eye which had been previously incubated with cMEM without phenol red at 32 ± 1 °C for 1 hour and whose opacity had been measured.

The test item was incubated on the cornea for 4 hours at 32 ± 1 °C. After removal of the test item, opacity and permeability values were measured.

Hank’s Balanced Salt Solution (HBSS) was used as negative control. The negative control showed no irritating effect on the cornea and the calculated mean IVIS (In VitroIrritancy Score) was 0.92.

20% imidazole solution was used as positive control. The positive control induced serious eye damage on the cornea and was within two standard deviations of the current historical mean. The calculated mean IVIS was 103.09.

 

Under the conditions of this study, the test item[3R-(3α, 3aβ,6α,7β,8aα)]-octahydro-3,6,8,8-tetramethyl-1H-3a,7-methanoazulen-6-ol(Cedrol)showed no effects on the cornea of the bovine eye. The calculated mean IVIS was 1.30.

According to OECD Guideline no. 437 (Oct. 2017), a substance with an IVIS ≤ 3 requires no classification for eye irritation or serious eye damage.