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Acute Toxicity: oral

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acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2006-07-20 to 2006-2007-09-18
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Guideline study reliable without restrictions Minor deviations with no effect on the results of the study: - The stability of the test material was missing, but it was stated in the report that the test substance appeared to be stable under the conditions of the study. No evidence of instability, such as a change in colour or physical state, was observed. - According to the guideline, the volume for administration of the test substance should not exceed 1 ml /100g of body weight; however in the case of aqueous solution, 2 ml/100 g body weight can be considered. Also, the test substances should be administered in a constant volume. The test substance was not administered in a constant volume and the volume for nonaqueous solutions was exceeded. This was not considered to influence the results. - According to the guideline, the rats should be observed daily for a total of 14 days. One rat was not observed on day 9 for clinical signs. This test guideline deviation did not affect the validity of the study because no clinical signs were observed in this rat after the day of dosing.

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)
Version / remarks:
, adopted 2006-03-23
, see "rational for reliability"
GLP compliance:
Test type:
up-and-down procedure
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
Stearic acid, cobalt salt
EC Number:
EC Name:
Stearic acid, cobalt salt
Cas Number:
Molecular formula:
lambda2-cobalt(2+) dioctadecanoate
Details on test material:
- Name of test material (as cited in study report): Cobalt (II) stearate
- Physical state: Black solid
- Analytical purity: see composition below
- Composition of test material, percentage of components: 92.9 % Cobalt (II) Stearate (Percent Metal: 9.36 % Co)
- Lot No.: 19731MI
- Stability under test conditions: The test substance appeared to be stable under the conditions of the study. No evidence of instability, such as a change in colour or physical state, was observed.
- Melting point: 109.3 - 112.2 °C
No further information on the test material was stated.

Test animals

Crj: CD(SD)
Details on test animals or test system and environmental conditions:
- Source: Charles River Laboratories, Inc., Raleigh, North Carolina
- Age at study initiation: Approx. 10 or 11 weeks old on the day of dosing
- Weight at study initiation: 204.9 - 255.3 g (fasted body weight)
- Fasting period before study: The rats were fasted approx. 16 - 18 hours prior to dosing, with food being returned to the rats approx. 3 -4 hours after dosing.
- Housing: All animals were housed singly in stainless steel, wire-mesh cages suspened above cage boards.
- Diet (ad libitum): PMI® Nutrition International, LLC certified Rodent Lab Diet® 5002
- Water: ad libitum
- Quarantine period: At least 6 days

- Temperature: 18 - 26 °C
- Relative humidity: 30 - 70 %
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Administration / exposure

Route of administration:
oral: gavage
other: 0.1 % Tween-80 (V/V) in 0.5 % aqueous methylcellulose
Details on oral exposure:
The test item was suspended in 0.1 % Tween-80 (V/V) in 0.5 % aqueous methylcellulose.

MAXIMUM DOSE VOLUME APPLIED: Individual dose volumes were calculated using the fasted body weights obtained prior to dosing. The rats dosed at 175 or 550 mg/kg were dosed at a volume of 10 mL per kg of body weight. therats dosed at 2000 mg/kg were dosed at a volume of 20 mL per kg of body weight. Since the amount for one rat (2000mg/kg) exceeded 5 mL, the dose was administered in 2 portions, 16 minutes apart.The dose suspensions were stirred at least 30 minutes prior to and throughout the dosing procedure.

DOSAGE PREPARATION (if unusual): Cobalt distearate was in the form of pellets and was crushed into a fine poder with a mortar and pestle. The powder was suspended in the vehicles. The suspension was milled at high speed with glass beads for 15 - 19 hours on a shaker table. A new dose suspension was prepared for each day of dosing.
- Rationale for the selection of the starting dose: The starting dose level of 175 mg/kg was chosen based on the absence of toxicity data for this test substance.
No further information on the oral exposure was stated.
175 mg/kg, 550 mg/kg, 2000 mg/kg
No. of animals per sex per dose:
175 mg/kg: one female
550 mg/kg: one female
2000 mg/kg: three females
Control animals:
not specified
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations for mortality and signs of illness, injury, or abnormal behaviour were made daily throughout the study. The rats were observed for clinical signs at the beginning of fasting, just before dosing (test day 0), once during the first 30 minutes after dosing and 2 more times on the day of dosing, and once each day thereafter (day 9 excluded for one rat). The rats were weighed on test days -1 (day before dosing (weight before fasting)), 0 (day of dosing (weight after fasting)), 7, and 14.
- Necropsy of survivors performed: Yes
On test day 14 , the rats were euthanized and necropsied to detect grossly observable evidence of organ and tissue damage or dysfunction. The rats were anesthetized by carbon dioxide and euthanized by exsanguination.
No further information on the study design was stated
A software package (A0T425StatPgm) was used to determine the dose progression and to calculate the LD50.

Results and discussion

Effect levels
Dose descriptor:
Effect level:
> 2 000 mg/kg bw
No deaths occurred.
Clinical signs:
High carriage and ataxia were observed up to the day after dosing in the rat dosed at 550 mg/kg. Two rats dosed at 2000 mg/kg exhibited abnormal gait (hindlimb, bilateral, moderate) and/or high carriage on the day of dosing. No clinical signs of toxicity were observed in the remaining rats.
Body weight:
No body weight loss occurred after dosing.
Gross pathology:
There were no gross lesions found in the study.

Applicant's summary and conclusion

Interpretation of results:
not classified
Migrated information Criteria used for interpretation of results: EU
Under the conditions of this study, the oral LD50 for cobalt distearate was greater than 2000 mg/kg for female rats.
According to the criteria specified by Directive 67/548/EEC and subsequent regulations, the test item is not classified.
According to the EC Regulation No. 1272/2008 and subsequent regulations, the test item is not classified.