Reaction mass of 7,7-dimethyl-2-methylidenebicyclo[2.2.1]heptane and (1R)-2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane and (1S)-2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane and (1S)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 November 2017 - 12 November 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 7,7-dimethyl-2-methylidenebicyclo[2.2.1]heptane and (1R)-2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane and (1S)-2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane and (1S)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene

Molecular formula:

not applicable, multiconstituent substance

IUPAC Name:

Reaction mass of 7,7-dimethyl-2-methylidenebicyclo[2.2.1]heptane and (1R)-2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane and (1S)-2,2-dimethyl-3-methylenebicyclo[2.2.1]heptane and (1S)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene

Test material form:

liquid

Test animals / tissue source

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Deonar Abattoir slaughter house, Mumbai, Maharashtra.
- Characteristics of donor animals (e.g. age, sex, weight): 1-5 years of age.
- Storage, temperature and transport conditions of ocular tissue (e.g. transport time, transport media and temperature, and other conditions): transported under cold condition in Hank's Balanced Salt Solution containing antibiotics (penicillin at 100 IU/mL and streptomycin at 100 μg/mL).
- Time interval prior to initiating testing: eyes were used within 24 h from the slaughtering.
- indication of any existing defects or lesions in ocular tissue samples: Eyes were examined prior to use. Corneas from eyes free of visible defects were used.
- Indication of any antibiotics used: yes, penicillin at 100 IU/mL and streptomycin at 100 μg/mL.

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): 750 μL
- Concentration (if solution): undiluted

Duration of treatment / exposure:

10 min ± 30 s

Duration of post- treatment incubation (in vitro):

2 h ± 10 min

Number of animals or in vitro replicates:

3 replicates.

Details on study design:

SELECTION AND PREPARATION OF CORNEAS: All eyes were examined prior to use, corneas free from defects were dissected to a 2-3 mm rim and transferred to a container with Hank's Balanced Salt Solution. Corneas from eyes free of visible defects and with an opacity value inferior than 7 were used. The selected corneas were mounted on the corneal holders with the endothelial side against the O-ring of the posterior half of the holder. The anterior half of the holder was then placed on top of the cornea and fixed with screws. Both chambers were filled with pre-warmed phenol red free Eagle's Minimum Essential Medium (EMEM) and equilibrated at 32 ± 1ºC for at least 1h. Following the equilibration period, the medium was removed from both chambers and baseline opacity readings were taken for each cornea.

QUALITY CHECK OF THE ISOLATED CORNEAS: Corneas from eyes free of visible defects and with an opacity value inferior than 7 were used.

NUMBER OF REPLICATES: 3

NEGATIVE CONTROL USED: yes. Normal saline (0.9% w/v, Sodium Chloride Injection I.P.), source: Realcade Life Sciences Pvt. Ltd., batch no: R2010266.

POSITIVE CONTROL USED: yes. N,N-Dimethylformamide, source: Sigma Aldrich, batch no: BCBQ8511V.

APPLICATION DOSE AND EXPOSURE TIME: 750 μL of undiluted test item, 10 min exposure.

TREATMENT METHOD: closed chamber.

POST-INCUBATION PERIOD: no.

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: the corneal epithelium was washed until no visual evidence of test item was observed using EMEM (containing phenol red) and, once the medium was free of test item, a final rinse with phenol red-free EMEM was performed.
- POST-EXPOSURE INCUBATION: After rinsing, the corneas were incubated for an additional period of approximately 2 hours ± 10 minutes at 32 ± 1ºC.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: corneal opacity was measured with an opacitometer BASF-OP3.0 (Duratec, Germany)
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of microtiter plate reader (OD490)

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA: as indicated in the TG (see table below).

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

in vitro irritation score

Run / experiment:

mean

Value:

1.2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.94

Positive controls validity:

valid

Remarks:

140.10

Results 2

Irritation parameter:

cornea opacity score

Run / experiment:

mean

Value:

0.91

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.67

Positive controls validity:

valid

Remarks:

106.18

Results 3

Irritation parameter:

other: permeability

Run / experiment:

mean

Value:

0.019

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.018

Positive controls validity:

valid

Remarks:

2.261

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: no.

DEMONSTRATION OF TECHNICAL PROFICIENCY: yes

ACCEPTANCE OF RESULTS:
- A test is considered acceptable if: the positive control gives an IVIS that falls within two standard deviations of the current historical mean and negative/solvent controls gives values of opacity and permeability lower than upper limits for background values.
- Acceptance criteria met for negative control: yes (negative: opacity upper limit=2.52, permeability upper limit=0.099)
- Acceptance criteria met for positive control: yes (historical value range: 63.28 - 257.23, SD: 56.79; mean = 159.82, 2*SD = 113.57)

Any other information on results incl. tables

Table 1. In vitro Irritation Score.

Normal Saline (0.75 mL)
Cornea Holder N°	Io  (LUX)	I (Initial) (LUX)	Initial Opacity Value	I (Post Treatment) (LUX)	Post Treatment Opacity Value	Corr. Opacity Value	OD490 Value	Corr. OD490 Value	IVIS
14	1111	1010	4.41	984	5.56	1.15	0.063	0.018	1.42
15	1086	974	5.00	946	6.32	1.32	0.064	0.019	1.61
16	1105	980	5.50	990	5.05	-0.45	0.061	0.016	-0.21
Mean						0.67	-	0.018	0.94
SD						0.98	-	0.002	1.00

N,N-Dimethylformamide (0.75 mL)
Cornea holder N°	Io  (LUX)	I (Initial) (LUX)	Initial Opacity Value	I (Post Treatment) (LUX)	Post Treatment Opacity Value	Corr. Opacity Value	Final Opacity Value	OD490 Value	Corr. OD490 Value	Final OD490 Value	IVIS
11	1118	998	5.21	289	114.71	109.50	108.83	2.074	2.029	2.011	139.00
12	1114	996	5.14	297	110.02	104.88	104.21	1.464	1.419	1.401	125.23
13	1097	981	5.13	290	111.29	106.16	105.49	3.434	3.389	3.371	156.06
Mean							106.18	-	2.279	2.261	140.10
SD							2.39	-	1.009	1.009	15.44

Reaction Mass (Fenchene, Laevo Alpha Pinene, Laevo Camphene, Dextro Camphene) (0.75 mL)
Cornea holder N°	Io  (LUX)	I (Initial) (LUX)	Initial Opacity Value	I (Post Treatment) (LUX)	Post Treatment Opacity	Corr. Opacity	Final Opacity	OD490	Corr. OD490	Final OD490	IVIS Score
17	1088	970	5.27	934	6.99	1.72	1.05	0.099	0.054	0.036	1.59
18	1047	938	5.05	891	7.40	2.35	1.68	0.076	0.031	0.013	1.88
19	1074	952	5.53	938	6.20	0.67	0.00	0.072	0.027	0.009	0.14
Mean							0.91	-	0.037	0.019	1.20
SD							0.85	-	0.015	0.015	0.93

Keys: IVIS = In Vitro Irritation Score, Io =Baseline Reading (With medium but without cornea), I = LUX.Reading with Medium and Cornea, OD₄₉₀= Optical Density at 490 Wave Length, - = Not Applicable, Corr. = Corrected. Blank OD₄₉₀value = 0.045.

- InitialOpacity Value = [((Io⁄I)-b)/a)], Where I = Initial LUX, Io = Baseline Reading, Note: a (0.0251) and b (0.9894) are constant.

- Post TreatmentOpacity Value = [((Io⁄I)-b)/a)], Where, I = Post Treatment LUX, Io = Baseline Reading.

- Corr. Opacity Value = Post Treatment Opacity Value - Initial Opacity Value

- Final Opacity Value = Corr. Opacity Value – Mean Corr. Opacity Value of Control (Group I)

- Corr. OD₄₉₀Value = OD₄₉₀Value – Blank OD₄₉₀Value, Where Blank Value for this trial was 0.045

- Final OD₄₉₀Value = Corr. OD₄₉₀Value –Mean Corr.OD₄₉₀Value of Control (Group I)

- IVIS (Control) = Corr. Opacity Value + (15 x Corrected OD₄₉₀)

- IVIS (Treatment) = Final Opacity Value + (15 x Final OD₄₉₀)

Applicant's summary and conclusion

Interpretation of results:

other: Not classified (CLP Regulation EC no. 1272/2008)

Conclusions:

The test item is not irritating to the eye (no category) as the mean IVIS score in the BCOP test was found to be 1.20.

Executive summary:

An in vitro Bovine Corneal Opacity and Permeability study was conducted in order to determine the potential severe eye damaging effects of the test item according to the OECD guideline 437 under GLP conditions. Three sets consisting of three corneas each were tested: the first set was the negative control, and was treated with 750 μL normal saline; the second set was the positive control, and was treated with 750 μL of dimethylformamide and the third set was treated with 750 μL of test item. The corneas were exposured for 10 min after which the test item was washed and then the corneas were kept in incubation for 2 h at 32ºC. After incubation, opacity of the corneas was measured. Then, to determine permeability, 1 mL fluorescein solution (4 mg/mL) was applied on the anterior surface of the corneas, while fresh EMEM (phenol red-free) was added to the posterior chamber and, after 90 min incubation at 32ºC, the OD (490 nm) of the medium in the posterior chamber was measured. Acceptance criteria were met for positive and negative controls. The mean corneal opacity for the test item treated corneas was 0.91, the mean permeability was 0.0019 and the mean IVIS score was found to be 1.20. Therefore, the test item is not irritating to the eye (no category).