Amorphous Mesoporous Magnesium Carbonate

Eye irritation

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

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

Results

Results 1

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

Results 2

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 Score^1,2
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.