Samarium

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

16 May 2012 to 30 May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The surface of samarium metal oxidises on contact with air to form an outer layer of samarium oxide. It is therefore considered appropriate to read across information from samarium oxide to the metal where testing on the metal is not technically possible.

Cross-reference

Reason / purpose for cross-reference:

other: read-across target

Reference

Endpoint:

acute toxicity: dermal

Type of information:

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

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted on read-across material

Justification for type of information:

The surface of samarium metal oxidises on contact with air to form an outer layer of samarium oxide. It is therefore considered appropriate to read across information from samarium oxide to the metal where testing on the metal is not technically possible.

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Samarium (III) oxide

EC Number:

235-043-6

EC Name:

Samarium (III) oxide

Cas Number:

12060-58-1

Molecular formula:

O3Sm2

IUPAC Name:

Samarium (III) oxide

Test material form:

solid: particulate/powder

Details on test material:

- Appearance: yellowish powder
- Storage conditions: room temperature (20 ± 5°C)

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 7 weeks (males); 8 weeks (females)
- Weight at study initiation: 231 - 243 g (males), 196 - 216 g (females)
- Housing: Animals were housed individually in solid-bottomed clear polycarbonate cages with a stainless steel mesh lid.
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): ca. 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours dark/ 12 hours light

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Remarks:

(distilled)

Details on dermal exposure:

TEST SITE
- Area of exposure: Approximately 24 hours before treatment, fur was removed from the dorsal area of the trunk of the test area by clipping.
- % coverage: at least 10 %
- Type of wrap if used: Test material applications were held in place under gauze dressings.

REMOVAL OF TEST SUBSTANCE
Following the 24 hour exposure period the gauze dressings were removed and the treated areas were rinsed with distilled water.

TEST MATERIAL
- Amount(s) applied: 1 g or 4 g of test material was weighed and 5 or 20 mL of distilled water was added. The preparation was magnetically stirred to obtain a white solution just before administration. The preparation was administered under a volume of 10 mL/kg bw.

Duration of exposure:

24 hours

Doses:

2 000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: A check for mortality was conducted daily together with systematic examinations to identify any behavioural or toxic effects on the major physiological functions. Body weights were taken just before test material application (day 0) and again on days 2, 7 and 14.
- Necropsy of survivors performed: Yes

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

None of the animals died during the study.

Clinical signs:

other: No clinical signs that were related to treatment with the test material were observed.

Gross pathology:

No treatment-related effects were noted at necropsy.

Applicant's summary and conclusion

Interpretation of results:

other: Not classified in accordance with EU criteria

Conclusions:

Under the conditions of the study the acute dermal LD50 to male and female Sprague Dawley rats was determined to be in excess of 2 000 mg/kg bw.

Executive summary:

The acute dermal toxicity of the test material was investigated in a study which was conducted in accordance with the standardised guidelines OECD 402 and EU Method B.3, under GLP conditions.

During the study a group of 5 male and 5 female Sprague Dawley rats were exposed to a single dermal application of test material at the limit dose of 2 000 mg/kg bw under semi-occlusive conditions for 24 hours after which the test material was removed with distilled water. The rats were observed for 14 days.

None of the animals died during the study, no clinical signs that could be related to treatment with the test material were noted and all animals gained weight during the study. The macroscopic examination of the animals at necropsy revealed no treatment-related effects.

Therefore, under the conditions of the study, the acute dermal LD50 to male and female Sprague Dawley rats was determined to be in excess of 2 000 mg/kg bw.