Calcium sulfate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not specified

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed according to internationally accepted testing guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Calcium sulfate

EC Number:

231-900-3

EC Name:

Calcium sulfate

Cas Number:

7778-18-9

Molecular formula:

CaSO4

IUPAC Name:

calcium sulfate

Details on test material:

- Name of test material (as cited in study report): Calcium sulfate anhydrite
- Analytical purity: 92.9%
- Lot no: 7439
- Storage condition of test material: Kept at room temperature in the dark.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Provided by Grabjas Jordi
- Age at study initiation: ~ 12 weeks
- Weight at study initiation: 2.5 - 2.7 kg
- Housing: The rabbits were accommodated individually in stainless steel cages. The cages were provided with a rack floor and placed on shelves
- Diet: Rabbit standard diet ad libitum
- Water: ad libitum
- Acclimation period:


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 ± 2ºC
- Humidity (%): 40 - 70 %
- Photoperiod (hrs dark / hrs light): 12 h of light and 12 h of darkness every 24 h.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

no

Amount / concentration applied:

0.5 g, moistened with distilled water.

Duration of treatment / exposure:

4 h

Observation period:

The response in the application area was evaluated after 30 - 60 min and 24, 48 and 72 h approximately once the exposure period had finished.

Number of animals:

3 animals

Details on study design:

The animals were shaved 24 h before the application using an electric shaver. Fur was removed from the dorsal area and flanks from the pelvic waist to the scapular waist. Over the shaved and healthy skin of the right side, a square test area of approximately 6 cm2 was delimited.
The substance was applied using an only dose of 0.5 g moistened with distilled water. Each time the test substance was placed over the corresponding test area and covered with an hydrophillic gauze of 2.5 x 2.5 cm approximately. The semi-occlusive patches were attached to the animal body using surgical tape.
Finally a gauze band was wrapped around the trunk of the rabbit and it was stuck with hypoallergenic surgical tape to keep the bandage in place. The objective of this bandage was maximising the cutaneous absorption of the test substance.
After 4 h of exposure, the bandage and the patches were removed. The residual product was cleaned softly using cotton wet with distilled water.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 24 hours

Results 2

Irritation parameter:

edema 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:

0.33

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Results 4

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Results 5

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

30 min after the removal of the semi-occlusive patch, very light erythema (grade 1) was observed for the three animals. 24 h after the application, only 2 animals showed hardly visible erythema (grade 1). During the readings performed 48 and 72 h after the treatment, no dermal alterations were observed in rabbits, so that the study was considered finished after this reading.
The average of the erythema and edema assessments for the 3 animals after 24, 48 and 72 h was 0.2 and 0.0 respectively.

Other effects:

The behaviour and physical condition of the rabbits were normal during the whole study. There were no mortalities.

Any other information on results incl. tables

Table 1: Primary dermal irritation following application of 0.5 g of the test substance:

Animal No.	Reaction	30 – 60 min	24 h	48 h	72 h
970	Erythema	1	0	0	0
	Edema	0	0	0	0
966	Erythema	1	1	0	0
	Edema	0	0	0	0
987	Erythema	1	1	0	0
	Edema	0	0	0	0

Interpretation of results:

The substance was classified according to the following scale, in accordance with Guideline 83/467/CEE, Annex VI, part IIB.

A substance or preparation is considered irritant if the inflammation of the skin with duration of at least 24 h corresponds to one of the following values:

- average value for the whole group of animals:

Erythemose lesions - 2 or higher

Edematose lesions - 2 or higher

- or lesions equivalent to the average values mentioned above, calculated for each animal, to 2 animals at least.

It is necessary to use the measure performed in every reading (24, 48, 72 h) of each type of lesion to calculate the respective average values. A substance is considered corrosive if it produces tissue destruction in the whole skin thickness, to at least 1 animal. It is considered to produce burns if tissue lesions in the whole skin thickness appear in an exposure period no longer than 4 h. If tissue lesions in the whole skin thickness appear in an exposure period no longer than 3 min, the product is considered to produce serious burns.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Calcium sulfate is not irritating to skin.