Tantalum carbide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2000-09-23 to 2000-12-18

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study. Tantalum used as read-across partner for Tantalum carbide.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

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

Test material

Test material information

Constituent 1

Reference substance name:

Tantalum

EC Number:

231-135-5

EC Name:

Tantalum

Cas Number:

7440-25-7

IUPAC Name:

tantalum(2+)

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Ta MP STA-40 KD
- Physical state: grey powder
- Analytical purity: 99.9%
- Lot/batch No.: 20000804
- Expiration date of the lot/batch: not advided but assumed to be stable for six months from date of receipt
- Date of receipt: 2000-08-25
- 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: at least 12 weeks
- Weight at study initiation: 2.5 - 2.6 kg
- Housing: individually in stainless steel cages with perforated floors
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 ± 2
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Remarks:

test material moistened with distilled water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.5 g

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3

Details on study design:

TEST SITE
- 24 hours prior to application of the test material, hair was removed with electric clippers from the dorso-lumbar region of each rabbit exposing an area of skin approximately 100 mm x 100 mm.
Approximately 0.5 g test material was applied under a 2-ply 25 mm x 25 mm porous gauze pad, which had been moistened with 0.5 mL distilled water, to one intact skin site on each animal. Each treatment site was covered with "Elastoplast" elastic adhesive dressing for 4 hours. The animals were not restrained during the exposure period and were returned to their cages immediately after treatment.

REMOVAL OF TEST SUBSTANCE
- Washing: at the end of the exposure period, the semi-occlusive dressing and gauze pad were removed and the treatment site was washed with warm water (36 °C) to remove any residual test material. The treated area was blotted dry with absorbent paper.

CLINICAL SIGNS:
- All animals were observed daily for signs of ill health or toxicity

DERMAL RESPONSES:
- Examination of the treated skin was made on day 1 (approximately 60 minutes after removal of the dressings) and on days 2, 3 and 4 (equivalent to approximately 24, 48 and 72 hours after exposure).

SCORING SYSTEM: see field "Any other information on materials and methods incl. tables" for further information.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of three animals

Time point:

other: 24, 48 and 72 hours

Score:

0

Max. score:

0

Remarks on result:

other: no dermal irritation at all was observed

Results 2

Irritation parameter:

edema score

Basis:

mean

Remarks:

of three animals

Time point:

other: 24, 48 and 72 hours

Score:

0

Max. score:

0

Remarks on result:

other: no dermal irritation was observed

Irritant / corrosive response data:

There were no signs of toxicity or ill health in any rabbit during the observation period and no dermal irritation was observed at any time during the test.

Other effects:

N.A.

Any other information on results incl. tables

Table 1: Dermal reactions
Rabbit no. & sex	E= Erythema O= Oedema		Day
			1*	2	3	4
1369 male	E		0	0	0	0
	O		0	0	0	0
1370 male	E		0	0	0	0
	O		0	0	0	0
1371 male	E		0	0	0	0
	O		0	0	0	0

* 60 minutes after removal of the dressing

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In conclusions, in an acute dermal irritation/corrosion study according to OECD 404, the test item tantalum was found to be non-irritating.

Executive summary:

In a primary dermal irritation study (OECD 404), three male New Zealand white rabbits were exposed to 0.5 g of tantalum (99.9 %) for 4 hours to a body surface area of 2.5 cm² under semi-occlusive conditions. Signs of erythema and oedema were recorded at 1, 24, 48 and 72 hours after removal of the dressing . Tantalum did not cause any skin effects and is not considered under the conditions of the test as dermal irritant.

These tantalum data are used in a read-across approach to describe the skin irritation potential of tantalum carbide.