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

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16th September 2009 - 19th September 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:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal 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

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system 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: 2.26 or 2.78 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

IN-LIFE DATES: From: To: NDA

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

water

Remarks:

distilled

Controls:

no

Amount / concentration applied:

A quantity of 0.5 g of the test material, moistened with 0.5 ml of distilled water, was introduced under a 2.5 cm x 2.5 cm cotton gauze patch and placed in position on the shorn skin.

Duration of treatment / exposure:

4 hours

Observation period:

Immediately following removal of the patches and approximately 1, 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation.

Number of animals:

2

Details on study design:

On the day before the test each of a group of two rabbits was clipped free of fur from the dorsal/flank area using veterinary clippers. Only animals with a healthy intact epidermis by gross observation were selected for the study.
On the day of the test a suitable test site was selected on the back of each rabbit. A quantity of 0.5 g of the test material, moistened with 0.5 mL of distilled water, was introduced under a 2.5 cm x 2.5 cm cotton gauze patch and placed in position on the shorn skin. The patch was secured in position with a strip of surgical adhesive tape. To prevent the animals interfering with the patches, the trunk of each rabbit was wrapped in an elasticated corset and the animals were returned to their cages for the duration of the exposure period.
Four hours after application the corset and patches were removed from each animal and any residual test material removed by gentle swabbing with cotton wool soaked in distilled water.
Immediately following removal of the patches and approximately 1, 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored according to the following scale:

EVALUATION OF SKIN REACTIONS

Erythema and Eschar Formation: Value
No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beef redness) to eschar formation preventing grading of erythema 4

Oedema Formation: Value
No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 millimetre) 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure 4

Any other skin reactions, if present, were also recorded.
Individual bodyweights were recorded on Day 0 (the day of dosing) and at the end of the observation period.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: mean score for 24, 48 and 72 hours

Score:

0

Max. score:

0

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: mean score for 24, 48 and 72 hours

Score:

0

Max. score:

0

Results 3

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: mean score for 24, 48 and 72 hours

Score:

0

Max. score:

0

Results 4

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: mean score for 24, 48 and 72 hours

Score:

0

Max. score:

0

Other effects:

All animals showed expected bodyweight gain during the study.

Any other information on results incl. tables

Table 1: Individual Skin Reactions

Skin Reaction	Observation Time (following patch removal)	Individual Scores — Rabbit Number and Sex		Total
		68569 Male	68570 Male
Erythema/Eschar Formation	Immediately 1 Hour 24 Hours 48 Hours 72 Hours	0 0 0 0 0	0 0 0 0 0	(0) (0) 0 (0) 0
Oedema Formation	Immediately 1 Hour 24 Hours 48 Hours 72 Hours	0 0 0 0 0	0 0 0 0 0	(0) (0) 0 (0) 0
Sum of 24 and 72-hour Readings (S)       : 0
Primary Irritation Index (S/4)                    : 0/4 = 0.0
Classification                                            : NON-IRRITANT

( ) = Total values not used for calculation of primary irritation index

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 primary irritation index of 0.0 and was classified as non-irritant to rabbit skin according to the Draize classification scheme. No corrosive effects were noted.

Executive summary:

The skin irritation/corrosion potential of the test material was examined using 2 male New Zealand White rabbits.

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

•            OECD Guidelines for the Testing of Chemicals No. 404 "Acute Dermal Irritation/Corrosion" (adopted 24 April 2002)

•            Method B4 Acute Toxicity (Skin Irritation) of Commission Regulation (EC) No. 440/2008

•            United States Environmental Protection Agency Health Effects Test Guidelines OPPTS 870.2500 Acute Dermal Irritation       August 1998

The test material produced a primary irritation index of 0.0 and was classified as non-irritant to rabbit skin according to the Draize classification scheme. No corrosive effects were noted.