Reaction mass of ditungsten carbide and tungsten carbide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

1998-02-25 to 1999-09-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

ell documented, scientifically sound study that was conducted according to GLP and OECD guideline 404 with no deviations.

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH: The hypothesis is that properties are likely to be similar or follow a similar pattern because of the presence of a common metal ion, in this case tungstate.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES):
Source: Tungsten Carbide
Target: Fused tungsten carbide
3. CATEGORY APPROACH JUSTIFICATION: See Annex 3 in CSR
4. DATA MATRIX: See Annex 3 in CSR

Cross-reference

Reason / purpose for cross-reference:

read-across: supporting information

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Reference 2

Reference Type:

publication

Title:

SIDS Initial Assessment Report for SIAM 21 for Tungsten Carbide (12070-12-1), Washington DC,18-20 October, 2005

Author:

OECD-SIDS

Year:

2005

Bibliographic source:

UNEP Publications

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tungsten carbide

EC Number:

235-123-0

EC Name:

Tungsten carbide

Cas Number:

12070-12-1

Molecular formula:

CW

IUPAC Name:

tungsten carbide

Details on test material:

- Name of test material (as cited in study report): Tungsten carbide powder WC HC 240- Analytical purity > 99.98%.- Physical state: Grey powder- Storage condition of test material: Room temperature

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Ltd, Bicester, Oxon, England
- Age at study initiation: 10 to 11 weeks
- Weight at study initiation: 2.4 to 2.6 kg
- Housing: Individually in stainless steel cages with perforated floors.
- Diet (ad libitum): STANRAB (P) SQC Rabbit Diet-ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: Yes; time period not given.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 -22.5
- Humidity (%): 39-56%
- Air changes (per hr): 19
- Photoperiod (hrs dark / hrs light): 12 light (0700-1900 hrs)/12 dark

IN-LIFE DATES: From: 1998-02-25 To: 1998-02-28

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: distilled water

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g
- Approximately 0.5 g of test substance was applied under a 25 mm x 25 mm gauze pad which was moistened with 0.5 mL of distilled water, to one intact skin site on each animal.

VEHICLE
- Amount(s) applied (volume or weight with unit): 0.5 mL of distilled water

Duration of treatment / exposure:

4 hours

Observation period:

4 days

Number of animals:

3 males

Details on study design:

TEST SITE
- Area of exposure: 24 hours prior to application of test substance, hair was removed with electric clippers from the dorso-lumbar region of each rabbit.
- % coverage: Exposed an area of skin approximately 100 x 100 mm.
- Type of wrap if used: Each site was covered with "Elastoplast" elastic adhesive dressing for 4 hours.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): After 4 days, the semi-occlusive dressing and gauze pad were removed and the treatment site was washed with warm water to remove any residual test substance. The treated area was blotted dry with absorbent paper.


SCORING SYSTEM: Dermal irritation was scored according to Draize

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

for all three animals

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

edema score

Basis:

mean

Remarks:

for all three animals

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No dermal response to treatment was observed in any animal throughout the study.

Other effects:

Clinical Signs: There were no signs of toxicity or ill health in any rabbit during the observation period.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

A single semi-occlusive application of Tungsten Carbide Powder- Pure to intact rabbit skin for four hours elicited no dermal irritation.

Executive summary:

No skin irritation data of sufficient quality are available for fused tungsten carbide (target substance). However, skin irritation data are available for tungsten carbide (source substance), which will be used for read-across. Due to similar water solubility and lower toxicity for the target substance compared to the source substance, the resulting read-across from the source substance to the target substance is appropriate. In addition, read-across is appropriate because the classification and labelling is similar for the source substance than the target substance, the PBT/vPvB profile is the same, and the dose descriptors are, or are expected to be, lower for the source substance. For more details, refer to the read-across category approach included in the Category section of this IUCLID submission and/or as an Annex in the CSR.