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:

between 07 November 2006 and 10 November 2006.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

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

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 30/08/05; Date of signature: 19/01/07

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

IUPAC Name:

hexamagnesium(2+) trihydrate decahydroxide sulfate

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Limited, Bicester, Oxon, UK.
- Age at study initiation: twelve to twenty weeks old.
- Weight at study initiation: 2.0 to 3.5 kg
- Housing: The animals were individually housed in suspended cages.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least five days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 to 23°C
- Humidity (%): 30 to 70%
- Air changes (per hr): at least fifteen changes per hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.


IN-LIFE DATES: From: Day 1 To: 72 hours after application.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g
- Concentration (if solution): not applicable


VEHICLE
- Amount(s) applied (volume or weight with unit): test material moistened
- Concentration (if solution): not applicable
- Lot/batch no. (if required): not applicable
- Purity: not applicable

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: dorsal/flank area
- % coverage: 10%
- Type of wrap if used: cotton gauze patch secured in position with a strip of surgical adhesive tape.


REMOVAL OF TEST SUBSTANCE
- Washing (if done): any residual test material removed by gentle swabbing with cotton wool soaked in distilled water.
- Time after start of exposure: 4 hours


SCORING SYSTEM: Draize scheme

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

24/48/72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 24 hours

Results 2

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 3

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Results 4

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Results 5

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 6

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 7

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Other effects:

None

Any other information on results incl. tables

The individual scores for erythema/eschar and oedema are given in Table 1.

Very slight erythema was noted at all treated skin sites one hour after patch removal and at two treated skin sites at the 24-hour observation.

One treated skin site appeared normal at the 24-hour observation and the remaining two treated skin sites appeared normal at the 48-hour observation.

Table1               IndividualSkin Reactions

Skin Reaction	Observation Time	Individual Scores – Rabbit Number and Sex			Total
		65078 Male	65079 Male	65080 Male
Erythema/Eschar Formation	1 Hour	1	1	1	(3 )
	24 Hours	0	1	1	2
	48 Hours	0	0	0	( 0 )
	72 Hours	0	0	0	0
Oedema Formation	1 Hour	0	0	0	( 0 )
	24 Hours	0	0	0	0
	48 Hours	0	0	0	( 0 )
	72 Hours	0	0	0	0
Sum of 24 and 72-hour Readings (S):              2
Primary Irritation Index (S/6)                             :              2/6 = 0.3
Classification                                                       :              MILD IRRITANT

 

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

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test material has a primary irritation index of 0.3. The average score after 24/48/72 hours for erythema was 0/0.33/0.33 for animal 1, 2 and 3. The average score after 24/48/72 hours for edema was 0/0/0 for animal 1, 2 and 3. Therefore the substance is not classified according to the EU CLP regulation (EC No 1272/2008) for skin irritation.

Executive summary:

Introduction. 

The study was performed to assess the irritancy potential of the test material to the skin of the New Zealand White rabbit. 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)

§        Method B4 Acute Toxicity (Skin Irritation) of Commission Directive 2004/73/EC

Results. 

A single 4-hour, semi-occluded application of the test material to the intact skin of three rabbits produced very slight erythema. One treated skin site appeared normal at the 24-hour observation and the remaining two treated skin sites appeared normal at the 48-hour observation.

Conclusion. 

The test material has a primary irritation index of 0.3. The average score after 24/48/72 hours for erythema was 0/0.33/0.33 for animal 1, 2 and 3. The average score after 24/48/72 hours for edema was 0/0/0 for animal 1, 2 and 3. Therefore the substance is not classified according to the EU CLP regulation (EC No 1272/2008) for skin irritation.