Tungsten disulphide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

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)

Test material

Test material information

Constituent 1

Reference substance name:

Tungsten

EC Number:

231-143-9

EC Name:

Tungsten

Cas Number:

7440-33-7

Molecular formula:

W

IUPAC Name:

tungsten

Constituent 2

Reference substance name:

Sulfur

EC Number:

231-722-6

EC Name:

Sulfur

Cas Number:

7704-34-9

Molecular formula:

S

IUPAC Name:

sulfur

Test material form:

solid: particulate/powder

Details on test material:

- Particle size distribution: D50= 3.1 um; D90=6.5 um
- Mass median aerodynamic diameter (MMAD):
- Density: 7.69 g/cm3

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:16031/01
- Expiration date of the lot/batch:01 April 2002
- Purity test date:>98%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:At room temperature in the dark
- Stability under test conditions:Stable
- Solubility and stability of the test substance in the solvent/vehicle:Water- Not Indicated

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The powdery test substance was moistened with water (Milli-U), immediately before application, to ensure close contact with the animal's skin.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Kisslegg, Germany.
- Age at study initiation: at least 6 weeks old
- Weight at study initiation: between 1.0 and 3.5 kg
- Housing:labelled cages with perforated floors (Scanbur, Denmark, dimensions 53.5x63x38.5 cm)
- Diet (e.g. ad libitum): Standard laboratory rabbit diet approx. 100 g. per day
- Water (e.g. ad libitum):Free access to tap-water
- Acclimation period:at least 5 days before start of treatment under laboratory conditions

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21±3°C
- Humidity (%): 30-70%
- Air changes (per hr): 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours dark per day

IN-LIFE DATES: From: To:

Test system

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

water

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 grams
- Concentration (if solution):

VEHICLE
- Amount(s) applied (volume or weight with unit):0.4 ml
- Concentration (if solution):
- Lot/batch no. (if required):
- Purity:

NEGATIVE CONTROL
- Amount(s) applied (volume or weight):
- Concentration (if solution):

POSITIVE CONTROL
- Amount(s) applied (volume or weight):
- Concentration (if solution):

Duration of treatment / exposure:

4 hours

Observation period:

1, 24, 48 and 72 hours after exposure

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: flank
- % coverage: 150 square centimeters
- Type of wrap if used: metalline patch which was wrapped around the abdomen and secured with Coban elastic bandage

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the skin cleaned of residual test substance using water and ethanol
- Time after start of exposure:Four hours after the application

OBSERVATION TIME POINTS
(indicate if minutes, hours or days)
1, 24, 48 and 72 hours
SCORING SYSTEM:
- Method of calculation:
Erythema and eschar formation:
No erythema 0
Very slight erythema (barely perceptible} 1
Well-defined erythema 2
Moderate to severe erythema ........................................................................................•. 3
Severe erythema (beet redness}• 4
•. Where signs of necrosis or corrosion (injuries in depth} prevent erythema scoring, the maximum grade for erythema (= 4) is given.
Oedema formation:
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 millimeter) 3
Severe oedema (raised more than 1 millimeter and extending beyond the area of exposure)4

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal: #86, 87, 91

Time point:

24/48/72 h

Score:

0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

erythema score

Basis:

animal: #91

Time point:

72 h

Score:

0

Reversibility:

not specified

Remarks on result:

other:

Remarks:

No scoring possible due to grey staining of the skin by the test substance

Results 3

Irritation parameter:

edema score

Basis:

animal: #86, 87, 91

Time point:

24/48/72 h

Score:

0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Results 4

Irritation parameter:

edema score

Basis:

animal: #91

Time point:

72 h

Score:

0

Reversibility:

not specified

Remarks on result:

other:

Remarks:

No scoring possible due to grey staining of the skin by the test substance

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

Based on the results and according to the EC criteria for classification and labelling requirements for dangerous substances and preparations (Guidelines in Commission Directive 93/21/EEC), TUNGSTEN DISULFIDE does not have to be classified and has no obligatory labelling requirement for skin irritation.

Executive summary:

Primary skin irritation/corrosion study with TUNGSTEN DISULFIDE in the rabbit (4-hour semi­occlusive application).

 The study was carried out based on the guidelines described in: EC Commission Directive 92/69/EEC, 8.4, "Acute Toxicity - Skin irritation" and OECD No.404, "Acute Dermal Irritation/Corrosion".

 Three rabbits were exposed to 0.5 grams of TUNGSTEN DISULFIDE, applied onto clipped skin for 4 hours using a semi-occlusive dressing. Observations were made 1, 24, 48 and 72 hours after exposure.

 No skin irritation was caused by 4 hours exposure to TUNGSTEN DISULFIDE.

Grey staining of the treated skin by the test substance was observed on days 1, 2, 3 and/or 4, which hampered the scoring of the skin reactions on day 1, but did not hamper the scoring of the skin reactions on days 2, 3 and 4.

 Based on the results and according to the EC criteria for classification and labelling requirements for dangerous substances and preparations (Guidelines in Commission Directive 93/21/EEC), TUNGSTEN DISULFIDE does not have to be classified and has no obligatory labelling requirement for skin irritation.