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Diss Factsheets

Toxicological information

Acute Toxicity: oral

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Administrative data

acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2009-07-13 to 2009-07-31
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Guideline study reliable without restrictions Minor deviations without an effect on the results: - According to the guideline, the animals are observed at least once during the first 30 minutes after dosing, periodically during the first 24 hours (with special attention given during the first 4 hours), and daily thereafter, for a total of 14 days. In this study the animals were observed during the first several hours post-dosing and at least once daily thereafter for 14 days after dosing. -According to the guideline, the rational for the starting dose should be stated. This was missing from the study report.

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)
, see "Rationale for reliability"
GLP compliance:
Test type:
up-and-down procedure
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
Calcium thiosulphate
EC Number:
EC Name:
Calcium thiosulphate
Cas Number:
Molecular formula:
calcium thiosulfate
Details on test material:
- Name of test material (as cited in study report): Aqueous solution of calcium thiosulfate (CaTS)
- Molecular formula: CaS2O3
- Physical state: Colourless, aqueous solution
- Composition of test material, percentage of components: Calcium thiosulfate : 23.7 %; Water: 76.3 %
- Lot No.: CaTS-Q6
- Expiration date of the lot: Not applicable
- Stability under test conditions: Test substance was expected to be stable for the duration of testing.
- Storage condition of test material: At room temperature
- pH: 6.5
- Solubility: Soluble in water
No further information on the test material was stated.

Test animals

Details on test animals or test system and environmental conditions:
- Source: Ace Animals, Inc., Boyertown, PA
- Age at study initiation: 8 weeks
- Weight at study initiation: 164 - 186 grams
- Fasting period before study: Prior to each dosing, experimetnally naive rats were fasted overnight by removing the feed from their cages. During the fasting period, the rats were examined for health and weighed (initial). Feed was replaced approximately 3 -4 hours after dosing.
- Housing: The animals were singly housed in suspended stainless steel caging with mesh floors which conform to the size recommendations in the most recent "Guide for the Care and USe of Laboratory Animals DHEW (NIH)". Litter paper was placed beneath the cage and was changed at least three times per week.
- Diet: Purina Rodent Chow #5012
- Water (ad libitum): Filtered tap water
- Acclimation period: 6 - 10 days

- Temperature: 20 - 23 °C
- Relative humidity: 56 - 70 %
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Administration / exposure

Route of administration:
oral: gavage
unchanged (no vehicle)
Details on oral exposure:
An initial limit dose of 2000 mg/kg was administered to one healthy female rat by oral gavage. Due to the absence of mortality in this animal, four additional females sequentially received the same dose level.

MAXIMUM DOSE VOLUME APPLIED: Individual doses were calculated based on the intial body weights, taking into account the specific gravity (determined by EPSL) of the test substance. Dose volume: 0.26 - 0.30 ml
- Specific gravity: -1.243 g/ml

DOSAGE PREPARATION: The test substance was administered as received.
No further information on the oral exposure was stated.
2000 mg/kg
No. of animals per sex per dose:
5 females
Control animals:
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Individual body weights of the animals were recorded prior to test substance administration (initial) and again on Days 7 and 14 (termination) following dosing. The animals were observed for mortality, signs of gross toxicity, and behavioural changes during the first several hours post-dosing and at least once daily thereafter for 14 days after dosing. Observations included gross evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behavior pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhea, and coma.
- Necropsy of survivors performed: Yes, all rats were euthanized via CO2 inhalation at the end of the 14-day observation period. Gross necropsies were performed on all animals. Tissues and organs of the thoracic and abdominal cavities were examined.
No further information on the study design was stated.
No data

Results and discussion

Effect levels
Dose descriptor:
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
All animals survived.
Clinical signs:
other: There were no signs of gross toxicity, adverse pharmacologic effects, or abnormal behaviour. The rats appeared active and healthy during the study.
Gross pathology:
No gross abnormalities were noted for any of the animals when necropsied at the conclusion of the 14-day observation period.
Other findings:
No data

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 acute oral LD50 of Aqueous solution of calcium thiosulfate (CaTS) is greater than 2000 mg/kg bw in female rats.
According to the criteria specified by Directive 67/548/EEC and subsequent regulations, the test item is not classified as acute toxic via the oral route.
According to the EC Regulation No. 1272/2008 and subsequent regulations, the test item is not classified as acute toxic via the oral route.