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Toxicological information

Eye irritation

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Administrative data

Endpoint:
eye irritation, other
Remarks:
ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15.3.2015-16.3.2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted according to Guidelines in a GLP-certified laboratory

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)
Deviations:
no
GLP compliance:
yes
Remarks:
Self-certified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
Identification: Magnesium hydroxide
Molecular formula: Mg(OH)2
Molecular weight: 58.32

Test animals / tissue source

Species:
other: Bovine
Strain:
not specified
Details on test animals or tissues and environmental conditions:
Bovine eyes from young cattle were obtained from the slaughterhouse, where the eyes were excised by a slaughterhouse employee as soon as possible after slaughter. The eyes were collected and transported in physiological saline in a suitable container and were used within 30 minutes.

Test system

Vehicle:
physiological saline
Controls:
yes, concurrent no treatment
Amount / concentration applied:
Unknown
Duration of treatment / exposure:
topical treatment for 240 ± 10 minutes
Observation period (in vivo):
After incubation with the test substance, the solutions were removed, fresh cMEM was added and an opacitiy determination was performed without any further incubation
Number of animals or in vitro replicates:
Three corneas were used in each treatment group
Details on study design:
REMOVAL OF TEST SUBSTANCE
- Washing: After the incubation with the test substance, corneas were washed at least 3 times with cMEM prior to determination of opacity
- Time after start of exposure: 240 ± 10 minutes

OPACITY:
The opacitometer determined the difference in light transmission between each control and treated cornea and an air filled chamber. The numerical opacity value was displayed and recorded. The change in opacity for each individual cornea was calculated by subtracting the initial opacity reading from the post-treatment reading. The corrected opacity was calculated by subtracting the opacity of the negative control.

PERMEABILITY
Following the final opacity method, permeability of the cornea to Na-fluorescein was evaluated. The medium of both compartments (anterior compartment first) was removed. The posterior compartment was refilled with fresh cMEM. The anterior compartment was filled with 1 ml of Na-fluorescein solution. The corneas were completely covered and were incubated in a horizontal position for 90 ± 5 minutes at 37 ± 1 °C.

After the incubation period, the medium in the posterior compartment of each holder was removed and placed into a sampling tube labelled according to holder number. 360 µl of the medium from each sampling tube was transferred to a 96-well plate. The optical density at 490 nm of each sampling tube was measured in triplicate using a microplate reader.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
overall irritation score
Basis:
mean
Time point:
other: 240 min
Score:
ca. 5.1
Max. score:
7.1
Remarks on result:
other: in vitro irritancy score
Irritation parameter:
other: Opacity
Basis:
mean
Time point:
other: 240 min
Score:
ca. 5
Max. score:
7
Irritant / corrosive response data:
See " Any other information on results incl. tables".
Other effects:
ND

Any other information on results incl. tables

Table 1 Summary of opacity, permeability and in vitro scores

Treatment

 

Mean Opactiy

Mean Permeability 

 MeanIn vitroIrritation Score1,2

 Negative control  0  0.000  0.0
 Positive control  80  2.490  117
 Magnesium hydroxide  5  0.006  5.1

1. Calculated using the negative control mean opacity an mean permeability values.

2. In vitro irritancy score (IVIS)= mean opacity + (15X mean OD490value).

Table 2. Opacity score

Eye

Opacity before treatment

Opacity after treatment

Final opacity

Negative control corrected final opacity

Mean opacity

Negative control

1

0

0

0

0

0

2

0

1

1

1

3

0

0

0

0

Positive control

4

0

80

80

80

80

5

0

79

79

79

6

0

81

81

81

Magnesium hydroxide

10

0

6

6

6

5

11

0

3

3

3

12

0

7

7

7

 

Table 3. Permeability score (corrected)

e

Dilution factor

Corrected OD4901

Corrected OD4902

Corrected OD4903

Average

OD490

Final

OD490

Average

OD

Negative control

1

1

0.014

0.001

0.004

0.006

0.006

0.000

2

1

0.000

0.000

0.003

0.001

0.001

3

1

-0.001

-0.008

-0.009

-0.006

-0.006

Positive control

4

6

0.369

0.366

0.372

0.369

2.214

2.490

5

6

0.349

0.362

0.354

0.355

2.130

6

6

0.527

0.518

0.519

0.521

3.126

Magnesium hydroxide

10

1

0.008

0.008

0.011

0.009

0.009

0.006

11

1

0.008

0.002

0.000

0.003

0.003

12

1

0.006

0.004

0.005

0.005

0.005

Table 4. In vitro irritancy score

Eye

Negative control corrected final opacity

Negative control corrected final OD490

In vitro irritancy score

Negative control

1

0

0.006

0.1

2

0

0.001

1.0

3

0

-0.006

-0.1

Positive control

4

80

2.214

113.2

5

79

2.130

111.0

6

81

3.126

127.9

Magnesium hydroxide

10

6

0.009

6.1

11

3

0.003

3.0

12

7

0.005

7.1

In vitro irritancy score (IVIS) = mean opacity + (15 x mean OD490value)

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Remarks:
Not irritating
Conclusions:
Since the mean in vitro irritancy score for Magnesium Hydroxide was below 55.1 after 240 minutes treatment, Magnesium Hydroxide is not classed as an irritant in the BCOP test.
Executive summary:

Screening for the eye irritancy potential of Magnesium hydroxide using the BCOP test. The study procedures were based on OECD guidelines. Magnesium hydroxide did not induce ocular irritation through both endpoints, resulting in a meanin vitroirritancy score of 5.1 after 240 minutes of treatment. Since this score is below 55.1 after 240 minutes treatment, Magnesium hydroxide is not classified as an irritant in the BCOP test.