Reaction mass of (2Z)-5-[(1R,3R,6S)-2,3-dimethyltricyclo[2.2.1.02,6]hept-3-yl]-2-methyl-2-penten-1-ol and (2Z)-2-methyl-5-[(1S,2R,4R)-2-methyl-3-methylenebicyclo[2.2.1]hept-2-yl]-2-penten-1-ol

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 January 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study conducted according to OECD test Guideline No. 438 without any deviation.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye 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:

25 June 2018

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

UK GLP Compliance Monitoring Programme (inspected on 21/08/2018 / signed on 19/11/2018)

Test material

Test material information

Constituent 1

Reference substance name:

5-(2,3-dimethyltricyclo[2.2.1.02,6]hept-3-yl)-2-methylpent-2-en-1-ol, stereoisomer

EC Number:

204-102-8

EC Name:

5-(2,3-dimethyltricyclo[2.2.1.02,6]hept-3-yl)-2-methylpent-2-en-1-ol, stereoisomer

Cas Number:

115-71-9

Molecular formula:

C15H24O

IUPAC Name:

5-(2,3-dimethyltricyclo[2.2.1.0~2,6~]hept-3-yl)-2-methylpent-2-en-1-ol

Constituent 2

Reference substance name:

[1S-[1α,2α(Z),4α]]-2-methyl-5-(2-methyl-3-methylenebicyclo[2.2.1]hept-2-yl)-2-penten-1-ol

EC Number:

201-027-2

EC Name:

[1S-[1α,2α(Z),4α]]-2-methyl-5-(2-methyl-3-methylenebicyclo[2.2.1]hept-2-yl)-2-penten-1-ol

Cas Number:

77-42-9

Molecular formula:

C15H24O

IUPAC Name:

2-methyl-5-(2-methyl-3-methylenebicyclo[2.2.1]hept-2-yl)pent-2-en-1-ol

Test material form:

liquid: viscous

Details on test material:

- Appearance: Colourless viscous liquid
- Storage conditions: Dry area, protected from light in a refrigerator (temp 2-8°C) stored under nitrogen in a closed container after every opening

Test animals / tissue source

Species:

chicken

Strain:

other: Spring chickens (Gallus Gallus e.g. Ross 308 Broiler)

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Spring chickens (Gallus Gallus e.g. Ross 308 Broiler), were supplied by Baileys Turkeys Ltd., Cheshire, UK
- Number of animals: 8
- Characteristics of donor animals (e.g. age, sex, weight): The chickens weighed approximately 3 kg and were approximately 56 days old prior to being humanely killed for human consumption.
- Storage, temperature and transport conditions of ocular tissue (e.g. transport time, transport media and temperature, and other conditions): Heads were removed immediately after the chickens had been humanely killed at the source, for use on the same day.
- Time interval prior to initiating testing: The time interval between collection of chicken heads and placing the eyes in the superfusion chamber following enucleation was minimized although all eyes had to fall within the acceptance criteria identified in the test guideline.
Date / Time Of Slaughter: 15.01.2020 0710 am
Date / Enucleation End Time: 15.01.2020 0940 am
- indication of any existing defects or lesions in ocular tissue samples: none
- Indication of any antibiotics used: none

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.03 mL of test item (undiluted)

Duration of treatment / exposure:

The test item was applied for 10 seconds and then rinsed from the eye using 20mL of isotonic saline

Duration of post- treatment incubation (in vitro):

Evaluation of the corneas at 30, 75, 120, 180 and 240 minutes (±5 minutes) after the eyes have been decontaminated

Number of animals or in vitro replicates:

Test item: 3 eyes
Positive control: 3 eyes
Negative control: 2 eyes

Details on study design:

SELECTION AND PREPARATION OF ISOLATED EYES
Eyes that had a high baseline fluorescein staining (>0.5) or corneal opacity score (>0.5) after the enucleation process were rejected.
Eyelids were carefully excised whilst taking care not to damage the cornea. The integrity of the cornea was measured with a drop of 2% (w/v) sodium fluorescein to the surface of the cornea and then rinsed with isotonic saline after a few seconds. The treated eyes were examined with the use of the Haag-Streit BQ 900 (Switzerland) microscope, to examine for damage to the cornea. An acceptable eye for the ICE test was one where the fluorescein retention and corneal opacity scores are ≤ 0.5.
Acceptable eyes were dissected from the skull and pulled from the orbit by holding the nictitating membrane firmly with surgical forceps. The tissue behind the eye was carefully removed with bent, blunt tipped scissors. Once the eye was removed from the orbit a portion of the optic nerve remained. Other connective tissue was removed from the eye on an absorbent tray liner.
Enucleated eyes were transferred to an appropriate clamp keeping the cornea vertical. They were then transferred to chambers within the superfusion apparatus ensuring the corneas received sufficient isotonic saline from the saline drip. The mean temperature of the chambers was at 32 ±1.5 °C.
Once all eyes were placed in the superfusion apparatus, the eyes were examined again with the Haag-Streit BQ 900 to ensure the eyes had not been damaged by the dissection procedure. Corneal thickness measurements are taken with a depth measuring device no. 1 on the Haag-Streit BQ 900 slit lamp microscope at the center of each cornea.
Eyes were replaced when: (i) the fluorescein score was > 0.5; (ii) the corneal opacity score was > 0.5; or (iii) there was any additional signs of damage, (iv) the corneal thickness measurements for individual eyes deviated more than 10% from the mean value for all eyes.

EQUILIBRATION AND BASELINE RECORDINGS
After the approval process the eyes were incubated for approximately 45 minutes for equilibrium purposes. Time zero measurements for corneal thickness and opacity were taken to serve as a baseline. The baseline for the fluorescein measurements were taken at dissection.

NUMBER OF REPLICATES
The test item and positive control item groups consisted of three eyes and the negative control item consisted of two eyes.

NEGATIVE CONTROL USED
0.03 mL of the negative control item, Sodium chloride 0.9% w/v, was applied to the cornea of each negative control eye.

POSITIVE CONTROL USED
0.03 g of the positive control item, Benzalkonium chloride (5% v/v), was similarly applied to the cornea of each positive control eye.

APPLICATION DOSE AND EXPOSURE TIME
- Immediately following the zero reference measurements, each test eye (including clamp) was removed from the superfusion apparatus and placed horizontally (cornea facing upwards) into a petri dish.
- 0.03 mL of test item was applied to the cornea. The entire surface of the cornea was evenly covered.

OBSERVATION PERIOD
- Treated corneas were evaluated prior to treatment and at 30, 75, 120, 180 and 240 minutes (± 5 minutes) after the eyes had been decontaminated with the isotonic saline.

REMOVAL OF TEST SUBSTANCE
- Volume and washing procedure after exposure period: The test item remained in place for 10 seconds and was then rinsed from the eye using 20 mL of isotonic saline. The treated eye (including clamp) was subsequently returned to the superfusion apparatus in the original upright position.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: Yes
- Damage to epithelium based on fluorescein retention: Yes
- Swelling: measured with optical pachymeter on a slit-lamp microscope; slit-width setting: Yes (e.g. pitting, sloughing or roughening of the epithelium).
- Macroscopic morphological damage to the surface: Yes

SCORING SYSTEM:
- Mean corneal swelling (%): Percentage corneal swelling was assessed from corneal thickness measurements. The calculation was expressed in the following formula:
[(corneal thickness at time (t) / corneal thickness at time = 0) / corneal thickness at time =0] x 100
Mean percentage of corneal swelling for all test eyes was calculated for all the time points. The overall category score was determined from the highest mean score for epithelial swelling as observed at any time point.
- Mean maximum opacity score: Corneal opacity was calculated with the most densely opacified areas for scoring. The mean value for all test eyes was calculated for all time points. The highest mean score, as observed at any time point was given an overall category for each test item.
0: No opacity
0.5: Very faint opacity
1: Scattered or diffuse areas; details of the iris clearly visible
2: Easily discernible translucent area; details of the iris are slightly obscured
3: Severe corneal opacity; no specific details of the iris are visible; size of the pupil is barely discernible
4: Complete corneal opacity; iris invisible
- Mean fluorescein retention score at 30 minutes post-treatment: The mean fluorescein retention scores for all test eyes are calculated at the 30 minute time interval only. These measurements are used for the overall classification for each test item.
0: No fluorescein retention
0.5: Very minor single cell staining
1: Single cell staining scattered throughout the treated area of the cornea
2: Focal or confluent dense single cell staining
3: Confluent large areas of the cornea retaining fluorescein

DECISION CRITERIA:
Results from corneal opacity, swelling, and fluorescein retention should be evaluated separately to generate an ICE class for each endpoint. The ICE classes for each endpoint are then combined to generate an Irritancy Classification for each test item.

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

cornea opacity score

Remarks:

maximal mean score

Run / experiment:

10 seconds exposure

Value:

0.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.8 (ICE Class II)

Positive controls validity:

valid

Remarks:

4.0 (ICE Class IV)

Remarks on result:

no indication of irritation

Remarks:

ICE Class II

Results 2

Irritation parameter:

fluorescein retention score

Run / experiment:

10 seconds exposure

Value:

0.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.5 (ICE Class I)

Positive controls validity:

valid

Remarks:

3.0 (ICE Class IV)

Remarks on result:

no indication of irritation

Remarks:

ICE Class II

Results 3

Irritation parameter:

percent corneal swelling

Remarks:

Maximal mean

Run / experiment:

10 seconds exposure

Value:

1.61

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

4.92 (ICE Class I)

Positive controls validity:

valid

Remarks:

44.63 (ICE Class IV)

Remarks on result:

no indication of irritation

Remarks:

ICE Class II

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system:
1/ Corneal Opacity Scores
Very faint opacity was noted in one negative control treated eye.
Scattered or diffused areas of opacity were noted in one negative control treated eye.
Complete corneal opacity was noted in all positive control treated eyes.
Very faint opacity was noted in one test item treated eye.
Scattered or diffused areas of opacity were noted in two test item treated eyes.
No morphological effects were noted in the test item, positive or negative control item treated eyes apart from a sunken cornea noted in one test item treated eye.
2/ Fluorescein Retention Scores
Very minor single cell staining was noted in the negative control treated eyes.
Confluent large areas of the cornea retaining fluorescein was noted in all positive control treated eyes.
Very minor single cell staining was noted in one test item treated eye.
Single cell staining scattered throughout the treated area of the cornea was noted in two test item treated eyes.

DEMONSTRATION OF TECHNICAL PROFICIENCY: yes
In order to confirm the acceptability of the test, a comparison was made with historical control data for negative and positive controls obtained by the laboratory (Annex 2). The test was considered acceptable as the concurrent negative and positive controls were identified as GHS Non-Classified and GHS Category 1 respectively.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes, the negative control is identified as GHS-Non Classified
- Acceptance criteria met for positive control: Yes, the positive control is identified as GHS Category 1
- Range of historical values if different from the ones specified in the test guideline: In order to confirm the acceptability of the test, a comparison was made with historical control data for negative and positive controls obtained by the laboratory. The test was considered acceptable as the concurrent negative and positive controls were identified as GHS Non-Classified and GHS Category 1 respectively.

Any other information on results incl. tables

Table 7.3.2/3: Individual Scores and Mean Scores for Corneal Effects – Test Item

End Point		Eye Number	Time (after decontamination)
			0 minutes	30 minutes	75 minutes	120 minutes	180 minutes	240 minutes
Corneal Opacity		3A	0.5	1	1	1	1	1
		6A	0.5	0.5	0.5	0.5	0.5	0.5
		8A	0.5	0.5	1	1	1	1
Mean			0.5	0.7	0.8	0.8	0.8	0.8
ICE Class			II
Fluorescein Retention		3A		1
		6A		0.5
		8A		1
Mean				0.8
ICE Class			II
Corneal Thickness		3A	0.60	0.60	0.60	0.64	0.64	0.64
		6A	0.65	0.62	0.62	0.60	0.60	0.61
		8A	0.61	0.60	0.62	0.63	0.63	0.64
Mean			0.62	0.61	0.61	0.62	0.62	0.63
Mean Corneal Swelling (%)				-2.15	-1.08	0.54	0.54	1.61
ICE Class			I
Epithelium Condition	3A			N	N	N	N	SC
	6A			N	N	N	N	N
	8A			N	N	N	N	N
ICE Classes Combined:			1 x I, 2 x II
Classification:			No Category

N= Normal

SC= Sunken Cornea

N= Normal

TA = Test item adherance

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the test item is not classified according to the Regulation (EC) No. 1272/2008 (CLP) and to the GHS.

Executive summary:

An in vitro eye irritation study was performed according to the OECD Guideline 438 and in compliance with GLP to evaluate the possible corrosivity or severe irritancy potential of the test item as measured by its ability to induce toxicity in an enucleated chicken eye. 

0.03 mL of the test item was applied onto the cornea of each of three enucleated eyes. A further three enucleated eyes were treated with positive control item. A further two enucleated eyes were treated with negative control item

The ocular reactions observed in eyes treated with the test item were:

- maximal mean score of corneal opacity: 0.8, corresponding to the ICE class II;

- mean score of fluorescein retention: 0.8, corresponding to the ICE class II;

- maximal mean corneal swelling: 1.61 % at 120 min after treatment corresponding to the ICE class I.

The combination of the three endpoints for the negative control, physiological saline solution, was 2 x I, 1 x II. Therefore, the negative control is classified as "No Category", as expected. The combination of the three endpoints for the positive control, was 3 x IV. Therefore, the positive control is classified as "Corrosive/Severe irritant", as expected.

Under the test conditions, the test item is not classified according to the Regulation (EC) No. 1272/2008 (CLP) and to the GHS.