Molybdenum disilicide

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990-06-25 to 1990-11-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Disodium molybdate

EC Number:

231-551-7

EC Name:

Disodium molybdate

Cas Number:

7631-95-0

Molecular formula:

MoO4.2Na

IUPAC Name:

Disodium tetraoxomolybdate

Specific details on test material used for the study:

- Name of test material (as cited in study report): Sodium molybdate
- Physical state: white crystalline powder
- Analytical purity: 46.03% Molybdenum, 18.69% sodium
- Purity test date: 1990-06-06
- Storage condition of test material: storage at room temperature

Test animals

Species:

rat

Strain:

other: Crl:CD (SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River UK, Kent, England
- Age at study initiation: four to six weeks
- Weight at study initiation: 108 to 140 g
- Housing: up to five rats of the same sex in metal cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24-29 °C
- Humidity (%): 67%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

Doses:

preliminary study: 250 and 1000 mg/kg bw
main study: 3200, 5000 and 6400 mg/kg bw

No. of animals per sex per dose:

preliminary study: 2
main study: 5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: on the day of treatment at frequent intervals for a period of 5 hours. On the subsequent days two times per day. Clinical signs were recorded at each observation.
- Frequency of weighing: on day the day of treatment, on day 8 and day 15
- Necropsy of survivors performed: yes

Statistics:

The acute median lethal oral dose (LD50) to male and female rats was calculated using the method of Finney (1971, Probit Analysis).
Where the slope was not significantly different from zero, approximate confidence limits were calculated by taking the LD50 estimate given and multiplying and dividing twice by the standard error obtained after adjustment for heterogeneity.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

4 233 mg/kg bw

Based on:

test mat.

Mortality:

After a single oral dose of Sodium molybdate at a concentration of 3200 mg/kg bw three male and one female died within 5 hours after treatment. At 5000 mg/kg bw one male died and two female animals died within 2 days after treatment. After treatment with 6400 mg/kg bw all animals died within 2 hours after treatment.

Clinical signs:

other: Piloerection was observed in all rats within five minutes after treatment. This sign was accompanied on Day 1 and/or later intervals by: - hunched posture, waddling and pallor of the extremities in all rats dosed at 3200 and 5000 mg/kg bw, less commonly a

Gross pathology:

No macroscopic abnormalities were observed

Any other information on results incl. tables

Preliminary study:

The results indicated that the acute median lethal oral dose (LD50) to male and female rats of Sodium molybdate was greater than 1000 mg/kg body weight.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, the oral LD50 value in rats after treatment with Sodium molybdate was 4233 mg/kg body weight.

Executive summary:

In an acute oral toxicity study (OECD 401) young adult Crl:CD (SD) rats (5 animals per sex and dose) were orally exposed to Sodium molybdate in corn oil at concentrations of 3200, 5000 and 6400 mg/kg bw. Animals were observed for 14 days. All animals died in the high dose group. At 5000 mg/kg bw one male died and two female animals died and at 3200 mg/kg bw three male and one female died. There were treatment related clinical signs and slight changes in body weight. No treatment-related gross pathology abnormalities were observed after 14 days. Based on the mortality occured after treatment with Sodium molybdate, the oral LD50 value both in female and male Crl:CD (SD) rats was considered to be 4233 mg/kg body weight.