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Toxicological information

Acute Toxicity: dermal

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Administrative data

Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1998-03-24 to 1999-06-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
other company data
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
yes
Remarks:
One animal was found to be above the specified weight range of 200-300 g on Day 1 prior to dosing. The deviation was not considered to have affected the integrity of the study.
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Tungsten Metal Powder
- Physical state: Grey powder
- Analytical purity: >99 %

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan UK Ltd Bicester, Oxon, England
- Age at study initiation: 8 to 11 wks
- Weight at study initiation: 235 to 304 g
- Housing: Individually in metal cages with wire mesh floors in Building R14 Rm 6
- Diet: ad libitum Special Diet Services RM1(E) SQC expanded pellet
- Water: ad libitum
- Acclimation period: 12 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.5 to 22
- Humidity (%): 34 to 59
- Air changes (per hr): 10 to 15
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: From: 1009-03-23 To: 1998-04-07

Administration / exposure

Type of coverage:
occlusive
Vehicle:
other: 1% w/v aqueous methylcellulose
Details on dermal exposure:
TEST SITE
- Area of exposure: Dorso-lumbar region
- % coverage: 10%
- Type of wrap if used: The test substance was applied by spreading it evenly over the prepared skin. The treatment area (50 x 50 mm ) was covered with porous gauze held in place with a non irritating dressing, and further covered by a waterproof dressing encircled firmly around the trunk of the animal.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The dressings were removed and the treated area of skin was washed with warm water to remove any residual test substance. The treated area was blotted dry with absorbent paper.
- Time after start of exposure: 24 hrs

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.56 ml/kg bodyweight (200 mg/kg bodyweight)
- Concentration (if solution): 357% w/v in 1% w/v aqueous methylcellulose

VEHICLE
- Concentration (if solution): 1% w/v aqueous methylcellulose
Duration of exposure:
24 hrs
Doses:
2000 mg/kg bodyweight.
No. of animals per sex per dose:
5 male and 5 female
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:Frequently on day 1 and then twice daily
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology

One day prior to treatment, hair was removed from the dorso-lumbar region of each rat, exposing an area equivalent to approximately 10% of the total body surface area.
The test substance was applied by spreading it evenly over the prepared skin. the treatment area (approximately 50 mm x 50 mm) was covered with porous gauze held in place with a non irritating dressing, and further covered by a waterproof dressing encricled firmly around the trunk of the animal.
Treatment in this manner was performed on Day 1 (day of dosing) of the study only.
At the end of the 24 hours exposure period the dressings was carefully removed and the treated area of skin was washed with warm water (30 to 40 C) to remove any residual test substance. The treated area was blotted dry with absorbent paper.

-Bodyweights: The bodyweight of each rat was recorded on Days 1 (prior to dosing), 8 and 15. Individual weekly bodyweight changes and group mean bodyweights were calculated.

-Macroscopic pathology: All animals were subjected to a macroscopic examination wihich consisted of opening the abdominal and thoracic cavities. The macroscopic appearance of all tissues was recorded.
Statistics:
no data

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Mortality:
There were no deaths.
Clinical signs:
Dermal responses were confined to a residual staining (grey) from the test substance on Day 2 only (staining did not impair dermal assessment) in all ten rats and accompanied at this time in one rat only by slight erythema (resolving by Day 3).
Body weight:
A minor bodyweight loss was evident in two female rats at Day 8 only. All remaining animals were considered to have achieved satisfactory bodyweight gains throughout the study.
Gross pathology:
No abnormalities were recorded at the macroscopic examination on Day 15.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The acute dermal lethal dose to rats of Tungsten Metal Powder was demonstrated to be greater than 2000 mg/kg bodyweight.