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Administrative data

Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
04 March 2016 to 08 March 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guidelineopen allclose all
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
Qualifier:
according to guideline
Guideline:
EU method B.47 (Bovine corneal opacity and permeability test method for identifying ocular corrosives and severe irritants)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

1
Chemical structure
Reference substance name:
2-(tetrapropenyl)succinic acid, monoester with propane-1,2-diol
EC Number:
257-836-6
EC Name:
2-(tetrapropenyl)succinic acid, monoester with propane-1,2-diol
Cas Number:
52305-09-6
Molecular formula:
C17H30O5 - C21H38O5
IUPAC Name:
2-[2-(2-hydroxy-1-methylethoxy)-2-oxoethyl]tetradecanoic acid
Test material form:
solid
Details on test material:
- Apperance: Yellow solid block
- Storage: Room temperature in the dark

Test animals / tissue source

Species:
cattle
Strain:
not specified
Details on test animals or tissues and environmental conditions:
SOURCE OF BOVINE EYES
Eyes from adult cattle (typically 12 to 60 months old) were obtained from a local abattoir as a by-product from freshly slaughtered animals. The eyes were excised by an abattoir employee after slaughter, and were placed in Hanks’ Balanced Salt Solution (HBSS) supplemented with antibiotics (penicillin at 100 IU/mL and streptomycin at 100 μg/mL). They were transported to the test facility over ice packs on the same day of slaughter. The corneas were prepared immediately on arrival.

Test system

Vehicle:
unchanged (no vehicle)
Remarks:
The test material was used as supplied.
Controls:
yes, concurrent positive control
yes, concurrent negative control
Amount / concentration applied:
TEST MATERIAL
- Amount applied: 0.75 mL
Duration of treatment / exposure:
10 minutes
Duration of post- treatment incubation (in vitro):
120 minutes
Number of animals or in vitro replicates:
Three corneas with opacity values close to the median value of all corneas were allocated to the negative control. Three corneas were also allocated to the test material and three corneas to the positive control material.
Details on study design:
SELECTION AND PREPARATION OF CORNEAS
All eyes were macroscopically examined before and after dissection. Only corneas free of damage were used.
The cornea from each selected eye was removed leaving a 2 to 3 mm rim of sclera to facilitate handling. The iris and lens were peeled away from the cornea. The isolated corneas were immersed in a dish containing HBSS until they were mounted in Bovine Corneal Opacity and Permeability (BCOP) holders.
The anterior and posterior chambers of each BCOP holder were filled with complete Eagle’s
Minimum Essential Medium (EMEM) without phenol red and plugged. The holders were incubated at 32 ± 1 ºC for 60 minutes. At the end of the incubation period each cornea was examined for defects. Only corneas free of damage were used.

QUALITY CHECK OF THE ISOLATED CORNEAS
The medium from both chambers of each holder was replaced with fresh complete EMEM. A pre-treatment opacity reading was taken for each cornea using a calibrated opacitometer. The average opacity for all corneas was calculated.

NUMBER OF REPLICATES
Three corneas with opacity values close to the median value of all corneas were allocated to the negative control. Three corneas were also allocated to the test item and three corneas to the positive control item.

NEGATIVE CONTROL USED
0.9% w/v sodium chloride solution.

POSITIVE CONTROL USED
Ethanol, used as supplied.

APPLICATION DOSE AND EXPOSURE TIME
The EMEM was removed from the anterior chamber of the BCOP holder and 0.75 mL of the test item or control items were applied to the appropriate corneas. The holders were gently tilted back and forth to ensure a uniform application of the item over the entire cornea. Each holder was incubated, anterior chamber uppermost, at 32 ± 1 ºC for 10 minutes.

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: At the end of the exposure period the test item and control items were removed from the anterior chamber and the cornea was rinsed three times with fresh complete EMEM containing phenol red before a final rinse with complete EMEM without phenol red. The anterior chamber was refilled with fresh complete EMEM without phenol red. A post-treatment opacity reading was taken and each cornea was visually observed.

- POST-EXPOSURE INCUBATION: The holders were incubated, anterior chamber facing forward, at 32 ± 1 ºC for 120 minutes.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: After incubation the holders were removed from the incubator, the medium from both chambers was replaced with fresh complete EMEM and a final opacity reading was taken.
- Corneal permeability: Following the final opacity measurement the permeability of the corneas to sodium fluorescein was evaluated. The medium from the anterior chamber was removed and replaced with 1 mL of sodium fluorescein solution (4 mg/mL). The dosing holes were plugged and the holders incubated, anterior chamber uppermost, at 32 ± 1 ºC for 90 minutes.
After incubation the medium in the posterior chamber of each holder was decanted and retained.
360 μL of medium representing each cornea was applied to a designated well on a 96-well plate and the optical density at 492 nm (OD492) was measured using the Anthos 2001 microplate reader.
- Others: Each cornea was visually observed. The condition of the cornea was visually assessed post treatment and post incubation.
The corneas were retained after testing for possible conduct of histopathology. Each cornea was placed into a pre-labelled tissue cassette fitted with a histology sponge to protect the endothelial surface. The cassette was immersed in 10 % neutral buffered formalin.

SCORING SYSTEM: In Vitro Irritancy Score (IVIS). Results from the two test method endpoints, opacity and permeability, were combined in an empirically derived formula to generate an In Vitro Irritancy Score. The following formula was used to determine the In Vitro Irritancy Score:

In Vitro Irritancy Score = mean opacity value + (15 x mean permeability OD492 value)

Additionally, the opacity and permeability values were evaluated independently to determine whether the test item induced a response through only one of the two endpoints.

Opacity Measurement: The change in opacity for each cornea (including the negative control) was calculated by subtracting the initial opacity reading from the final opacity reading. These values were then corrected by subtracting the average change in opacity observed for the negative control corneas. The mean opacity value of each treatment group was then calculated by averaging the corrected opacity values of each cornea for that treatment group.
Permeability Measurement: The corrected OD492 was calculated by subtracting the mean OD492 of the negative control corneas from the OD492 value of each treated cornea. The OD492 value of each treatment group was calculated by averaging the corrected OD492 values of the treated corneas for the treatment group.

DECISION CRITERIA:
≤ 3: No category. Not requiring classification to UN GHS or EU CLP.
> 3, ≤ 55: No prediction of eye irritation can be made.
> 55: Category 1. UN GHS or EU CLP Causes serious eye damage.

Results and discussion

In vitro

Results
Irritation parameter:
in vitro irritation score
Run / experiment:
Treatment with 0.75 mL of the test item
Value:
66.2
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
positive indication of irritation
Other effects / acceptance of results:
OTHER EFFECTS:
- Visible damage on test system: The corneas treated with the test item or the positive control item were cloudy post-treatment and post-incubation. The corneas treated with the negative control item were clear post-treatment and post-incubation.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The negative control gave opacity of ≤ 2.9 and permeability ≤ 0.103. The negative control acceptance criteria were therefore satisfied.
- Acceptance criteria met for positive control: The positive control In Vitro Irritancy Score was within the range of 29.6 to 52.0. The positive control acceptance criterion was therefore satisfied.

Any other information on results incl. tables

In Vitro Irritancy Scores

Treatment

In Vitro Irritancy Score

Test Material

66.2

Negative Control

0.4

Positive Control

47.4

Table 2: Individual and Mean Corneal Opacity and Permeability Measurements

Treatment

Cornea Number

 

Opacity

Permeability (OD)

In Vitro Irritancy Score

Pre-Treatment

Post-Treatment

Post Incubation

Post-Incubation - Pre‑Treatment

Corrected Value

 

Corrected Value

Negative Control

1

2

2

3

1

 

0.007

 

 

2

2

2

2

0

 

0.003

 

 

4

2

2

2

0

 

0.007

 

 

 

 

 

 

0.3*

 

0.006**

 

0.4

Positive Control

3

3

37

36

33

32.7

1.312

1.306

 

5

2

28

30

28

27.7

1.063

1.057

 

6

3

35

35

32

31.7

0.983

0.977

 

 

 

 

 

 

30.7+

 

1.114+

47.4

Test Item

7

2

46

65

63

62.7

0.281

0.275

 

8

5

40

66

61

60.7

0.700

0.694

 

9

3

26

58

55

54.7

0.418

0.412

 

 

 

 

 

 

59.3+

 

0.461+

66.2

OD = Optical density            

* = Mean of the post-incubation pre-treatment values         

** = Mean permeability                    

+ = Mean corrected value

Applicant's summary and conclusion

Interpretation of results:
Category 1 (irreversible effects on the eye) based on GHS criteria
Conclusions:
Under the conditions of the study, the test material was found to cause serious eye damage.
Executive summary:

A study was performed in vitro to assess the eye irritancy potential of the test material in accordance with the standardised guidelines OECD 437 and EU Method B.47 under GLP conditions.

The Bovine Corneal Opacity and Permeability (BCOP) test method was used to assess the potential of the test material to cause eye irritancy. The undiluted test item was applied for 10 minutes followed by an incubation period of 120 minutes. Negative and positive control items were tested concurrently. The two endpoints, decreased light transmission through the cornea (opacity) and increased passage of sodium fluorescein dye through the cornea (permeability) were combined in an empirically derived formula to generate an In Vitro Irritancy Score (IVIS).

The corneas treated with the test item or the positive control item were cloudy post treatment and post incubation. The corneas treated with the negative control item were clear post treatment and post incubation.

The positive control gave an IVIS of 47.4. The negative control had an IVIS of 0.4. The test material scored 66.2.

Under the conditions of the study, the test material was found to cause serious eye damage.

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