Magnesium hydroxide sulfate (Mg6(OH)10(SO4)), hydrate (1:3)

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 September 2009 - 01 October 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

483-390-9

EC Name:

-

Cas Number:

12508-61-1

Molecular formula:

H16Mg6O17S MgSO4 • 5Mg(OH)2 • 3H2O

IUPAC Name:

Magnesium hydroxide sulphate trihydrate

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories U.K. Ltd, Hillcrest, Belton, Loughborough, UK
- Age at study initiation: 12 – 20 weeks
- Weight at study initiation: 2.80 or 2.84 kg
- Housing: The animals were individually housed in suspended cages
- Diet (e.g. ad libitum): Free access to food (2030 Teklad Global Rabbit diet supplied by Harlan Teklad, Blackthorn, Bicester, Oxon, UK)
- Water (e.g. ad libitum): Free access to mains drinking water
The diet and drinking water were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.
- Acclimation period: At least 5 days.
The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 – 23 °C
- Humidity (%): 30 – 70% relative
Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study
- Air changes (per hr): At least 15
- Photoperiod (hrs dark / hrs light): 12 hours continuous light and 12 hours darkness

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: The left eye of each animal remained untreated for control purposes.

Amount / concentration applied:

Immediately before the start of the test, both eyes of the provisionally selected test rabbits were examined for evidence of ocular irritation or defect with the aid of a light source from a standard ophthalmoscope. Only animals free of ocular damage were used.
Initially, a single rabbit was treated. A volume of 0.1 ml of the test material, which was found to weigh approximately 60 mg (as measured by gently compacting the required volume into an adapted syringe) was placed into the conjunctival sac of the right eye, formed by gently pulling the lower lid away from the eyeball.
The left eye remained untreated and was used for control purposes.

Duration of treatment / exposure:

The upper and lower eyelids were held together for about one second immediately after treatment, to prevent loss of the test material, and then released.

Observation period (in vivo):

Immediately after administration of the test material, an assessment of the initial pain reaction was made. After consideration of the ocular responses produced in the first treated animal, a second animal was treated.

Assessment of ocular damage/irritation was made approximately 1 hour and 24, 48 and 72 hours following treatment, according to the Draize scale.
Any other ocular effects were also noted. Examination of the eye was facilitated by the use of the light source from a standard ophthalmoscope.

Number of animals or in vitro replicates:

2

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Not perfomed
- Time after start of exposure: N/A

SCORING SYSTEM: Draize Scale for Ocular Irritation.

Draize Scale for Scoring Ocular Irritation

1. CONJUNCTIVAE

(A) Redness (refers to palpebral and bulbar conjunctivae excluding cornea and iris)
Vessels normal............................................................................................................................................0
Vessels definitely injected above normal................................................................................................1
More diffuse, deeper crimson red, individual vessels not easily discernible....................................2
Diffuse beefy red.........................................................................................................................................3

(B) Chemosis
No swelling..................................................................................................................................................0
Any swelling above normal (includes nictitating membrane).............................................................1
Obvious swelling with partial eversion of lids.......................................................................................2
Swelling with lids about half closed.........................................................................................................3
Swelling with lids half closed to completely closed...............................................................................4

(C) Discharge
No discharge...............................................................................................................................................0
Any amount different from normal (does not include small amounts observed in inner
canthus of normal animals)......................................................................................................................1
Discharge with moistening of the lids and hairs just adjacent to lids...............................................2
Discharge with moistening of the lids and hairs a considerable area around the eye...................3

THE TOTAL SCORE = (A + B + C) x 2 MAXIMUM TOTAL = 20

2. IRIS

(D) Values
Normal.........................................................................................................................................................0
Folds above normal, congestion, swelling, circumcorneal injection (any or all
of these orcombination of any thereof) iris still reacting to light
(sluggish reaction is positive).................................................................................................................1
No reaction to light, haemorrhage, gross destruction (any or all of these)....................................2

THE TOTAL SCORE = D x 5 MAXIMUM TOTAL = 10

3. CORNEA

(E) Degree of Opacity (most dense area used)
No opacity...................................................................................................................................................0
Scattered or diffuse areas, details of iris clearly visible......................................................................1
Easily discernible translucent areas, details of iris slightly obscured..............................................2
Opalescent areas, no details of iris visible, size of pupil barely discernible....................................3
Opaque, iris not discernible through the opacity................................................................................4

(F) Area of Cornea Involved
One quarter (or less) but not zero..........................................................................................................1
Greater than one quarter but less than half...........................................................................................2
Greater than half but less than three quarters......................................................................................3
Greater than three quarters, up to whole area.......................................................................................4

THE TOTAL SCORE =(E x F) x 5 MAXIMUM TOTAL = 80

MAXIMUM TOTAL SCORE POSSIBLE = 110

TOOL USED TO ASSESS SCORE: standard opthalmoscope

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

conjunctivae score

Remarks:

Redness

Basis:

mean

Time point:

other: mean of 1h, 24h, 48h and 72 h for both animals treated

Score:

1.25

Max. score:

2

Reversibility:

fully reversible within: 72 h

Results 2

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: mean of 1h, 24h, 48h and 72 h for both animals treated

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 72 h

Results 3

Irritation parameter:

conjunctivae score

Remarks:

Discharge

Basis:

mean

Time point:

other: mean of 1h, 24h, 48h and 72 h for both animals treated

Score:

0.75

Max. score:

2

Reversibility:

fully reversible within: 72 h

Irritant / corrosive response data:

No corneal or iridial effects were noted during the test.

Moderate conjunctival irritation was noted in both treated eyes one and 24 hours after treatment with minimal conjunctival irritation noted at the 48-hour observation.

Both treated eyes appeared normal at the 72-hour observation.

Other effects:

One animal showed expected gain in bodyweight and the other animal showed no gain in bodyweight during the study.

Any other information on results incl. tables

Table 1: Individual Scores and Individual Total Scores for Ocular Irritation

Rabbit Number and Sex	68575 Male				68583 Male
	IPR = 2				IPR = 3
Time After Treatment	1 Hour	24 Hours	48 Hours	72 Hours	1 Hour	24 Hours	48 Hours	72 Hours
CORNEA E = Degree of Opacity F = Area of Cornea Involved	0   0	0   0	0   0	0   0	0   0	0   0	0   0	0   0
Score (E x F) x 5	0	0	0	0	0	0	0	0
IRIS D	0	0	0	0	0	0	0	0
Score (D x 5)	0	0	0	0	0	0	0	0
CONJUNCTIVAE A = Redness B = Chemosis C = Discharge	2 2 2	2 1 1	1 1 0	0 0 0	2 2 2	2 1 1	1 1 0	0 0 0
Score (A + B + C) x 2	12	8	4	0	12	8	4	0
Total Score	12	8	4	0	12	8	4	0

IPR = Initial pain reaction

Table 2: Initial Pain Reaction

When the material is instilled in the eye there may be an initial local pain reaction. The reaction will be graded as follows:

Class	Reaction by Animal	Descriptive Rating
0	No response	No initial pain
1	A few blinks only, normal within one or two minutes	Practically no initial pain
2	Rabbit blinks and tries to open eye, but reflex closes it	Slight initial pain
3	Rabbit holds eye shut and puts pressure on lids, may rub eye with paw	Moderate initial pain
4	Rabbit holds eye shut vigorously, may squeal	Severe initial pain
5	Rabbit holds eye shut vigorously, may squeal, claw at eye, jump and try to escape	Very severe initial pain

 

There is often no correlation between the initial pain and the subsequent eye irritation.

References

Draize J H (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.48 to 49).

Kay J H and Calandra J C (1962), J. Soc. Cosmet. Chem. 13, 281-289

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test material produced a maximum group mean score of 12.0 and was classified as a mild irritant (Class 4 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system.

Executive summary:

A single application of the test material to the non-irrigated eye of two rabbits produced moderate conjunctival irritation. Both treated eyes appeared normal at the 72-hour observation.

The method was designed to meet the requirements of the following:

•            OECD Guidelines for the Testing of Chemicals No. 405 "Acute Eye Irritation/Corrosion" (adopted 24 April 2002)

•            Method B5 Acute Toxicity (Eye Irritation) of Commission Regulation (EC) No. 440/2008

•            United States Environmental Protection Agency Health Effects Test Guidelines OPPTS 870.2400 Acute Eye Irritation

August 1998.

The test material produced a maximum group mean score of 12.0 and was classified as a mild irritant (Class 4 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system. However, the degree of irritation observed was not severe enough to classify the material according to the CLP Regulation (EC) No. 1272/2008.