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Toxicological information

Eye irritation

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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:
2017
Report date:
2017

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)
Version / remarks:
Adopted July 26th 2013
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Dilithium tetraborate
EC Number:
234-514-3
EC Name:
Dilithium tetraborate
Cas Number:
12007-60-2
Molecular formula:
B4Li2O7
IUPAC Name:
dilithium(1+) bicyclo[3.3.1]tetraboroxane-3,7-bis(olate)
Test material form:
solid: bulk

Test animals / tissue source

Species:
cattle
Strain:
not specified
Details on test animals or tissues and environmental conditions:
Bovine eyes from young cattle were obtained from the slaughterhouse were used in this study. The eyes were checked for unacceptable defects, such as opacity, scratches, pigmentation and neovascularization by removing them from the physiological saline and holding them in the light. Those exhibiting defects were discarded.

Test system

Vehicle:
unchanged (no vehicle)
Controls:
yes, concurrent positive control
yes, concurrent negative control
Amount / concentration applied:
Since no workable suspension in physiological saline could be obtained, the test item was used as delivered and added pure on top of the corneas.
Duration of treatment / exposure:
The eye damage of dilithium tetraborate was tested through topical application for approximately 240 minutes
Duration of post- treatment incubation (in vitro):
90 minutes
Number of animals or in vitro replicates:
Two identical experiments were undertaken
Details on study design:
The test consists of topical application of dilithium tetraborate on the epithelium of the bovine cornea for 4 hours. The non-surfactant solid test item is applied neat by direct application to the surface of the cornea. After exposure the corneas were thoroughly rinsed. The opacity of the corneas was determined directly after treatment and the permeability of the corneas was determined after a 90 minutes incubation period with sodium fluorescein.

Results and discussion

In vitro

Resultsopen allclose all
Irritation parameter:
cornea opacity score
Run / experiment:
Dilithium tetraborate - first experiment
Value:
2.8
Negative controls validity:
valid
Positive controls validity:
valid
Irritation parameter:
cornea opacity score
Run / experiment:
Dilithium tetraborate - second experiment
Value:
-1.3
Negative controls validity:
valid
Positive controls validity:
valid
Irritation parameter:
in vitro irritation score
Run / experiment:
Dilithium tetraborate - first experiment
Value:
37
Negative controls validity:
valid
Positive controls validity:
valid
Irritation parameter:
in vitro irritation score
Run / experiment:
Dilithium tetraborate - second experiment
Value:
14
Negative controls validity:
valid
Positive controls validity:
valid
Irritation parameter:
fluorescein retention score
Run / experiment:
Dilithium tetraborate - first experiment
Value:
2.297
Negative controls validity:
valid
Positive controls validity:
valid
Irritation parameter:
fluorescein retention score
Run / experiment:
Dilithium tetraborate - second experiment
Value:
0.99
Negative controls validity:
valid
Positive controls validity:
valid
Other effects / acceptance of results:
The corneas treated with dilithium tetraborate showed opacity values ranging from 2.0 to 3.9 and permeability values ranging from 0.317 to 3.903. The corneas were translucent after the 240 minutes of treatment with dilithium tetraborate. No pH effect of the test item was observed on the rinsing medium. Hence, the in vitro irritancy scores ranged from 7.4 to 60 after 240 minutes of treatment with Dilithium tetraborate.Since the results for dilithium tetraborate were spread over 2 categories (7.4, 60 and 44, respectively), the test was inconclusive and a repeat experiment was performed. The corneas treated with dilithium tetraborate showed opacity values ranging from -1.8 to -1.0 and permeability values ranging from 0.065 to 2.642. The corneas were partly translucent after the 240 minutes of treatment with dilithium tetraborate. A pH effect of the test item was observed on the rinsing medium, the corneas were rinsed until no colour change of the medium was observed. Hence, the in vitro irritancy scores ranged from -0.8 to 39 after 240 minutes of treatment with dilithium tetraborate. Since both tests provided inconclusive results, no conclusion can be drawn for eye irritation or serious eye damage.

Any other information on results incl. tables

First experiment

Treatment

Mean

Opacity

Mean

Permeability

Mean In vitro Irritation Score1, 2

Negative control

4.0

0.022

4.3

Positive control

116

1.744

143

Dilithium tetraborate

2.8

2.297

37

1  Calculated using the negative control mean opacity and mean permeability values for the positive control and test item.

2  In vitro irritancy score (IVIS) = mean opacity value + (15 x mean OD490 value).

 

Second experiment

Treatment

Mean

Opacity

Mean

Permeability

Mean In vitro Irritation Score1, 2

Negative control

2.5

0.021

2.8

Positive control

123

1.758

150

Dilithium tetraborate

-1.3

0.990

14

1    Calculated using the negative control mean opacity and mean permeability values for the positive control and test item.

2    In vitro irritancy score (IVIS) = mean opacity value + (15 x mean OD490 value).


 

Applicant's summary and conclusion

Interpretation of results:
study cannot be used for classification
Conclusions:
Both tests (experiment 1 & 2) provided inconclusive results, and therefore no conclusion can be drawn for eye irritation or serious eye damage.
Executive summary:

In a well conducted Bovine Corneal Opacity and Permeability Assay (BCOP), dilithium tetraborate was topically applied to the epithelium of the bovine cornea for 4 hours. The non-surfactant solid test item was applied neat by direct application to the surface of the cornea. After exposure the corneas were thoroughly rinsed. The opacity of the corneas was determined directly after treatment and the permeability of the corneas was determined after a 90 minutes incubation period with sodium fluorescein. The mean in vitro irritancy score was 37 and 14 after 240 minutes of treatment with the test item in the first and second experiment, respectively. The results for dilithium tetraborate were spread over 2 categories in both experiments. Because both tests provided inconclusive results, no conclusion can be drawn for eye irritation or serious eye damage. A further study on rabbits was therefore conducted (van Sas, 2017).