Registration Dossier

Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1974
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No GLP, equivalent or similar to OECD and EU guideline.
Cross-reference
Reason / purpose:
reference to other study

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Acute toxicity of cesium and rubidium compounds
Author:
Johnson, G.T.; Lewis, R.T. and Wagner, W.D.
Year:
1975
Bibliographic source:
Toxicology and applied pharmacology 32, 239-245 (1975)
Reference Type:
publication
Title:
Unnamed
Year:
1972

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
not specified
Qualifier:
equivalent or similar to
Guideline:
EU Method B.1 (Acute Toxicity (Oral))
Deviations:
not specified
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: crystalline

Test animals

Species:
rat
Strain:
other: Charles River albino rats
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River, cesarian-derived albino rats
- Weight at study initiation: 175 -250 g
- Fasting period before study: yes (overnight, 16 h)

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
VEHICLE
- Justification for choice of vehicle: good solubility in water

CsOH was dissolved in deionized-distilled water on a weight-to-weight basis prior to administration.
Doses:
500, 625, 781, 976, 1220, 1525 mg/kg bw.
No. of animals per sex per dose:
10 male rats
Control animals:
not specified
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: 1 and 4 h following administration and dayly thereafter for the 14-day period
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, histopathology, behavioral observations
Statistics:
The LD50 values and their 95% confidence limits were calculated by probit analysis of Finney (1971).

Results and discussion

Preliminary study:
no preliminary results.
Effect levels
Sex:
male
Dose descriptor:
LD50
Effect level:
1 026 mg/kg bw
Based on:
test mat.
Remarks:
Caesium hydroxide
95% CL:
929 - 1 133
Mortality:
All deaths occured within the first 72 h after dosing.
Clinical signs:
Clinical signs were increased respiration rate, ruffled fur, eye closing and huddling together. A bloody nasal exudate was noted in several animals receiving the higher doses.
Body weight:
No data on body weight.
Gross pathology:
Lethal and certain sublethal doses induced stomach and intestinal haemorrhage and adhesions of abdominal organs (stomach, pancreas, spleen, liver and small intestines). In the higher dose range, death was related to the degree of blockage of the gastrointestinal tract from the resultant adhesions and/or the leakage of the bloody fluid exudate into the peritoneal cavity.
Other findings:
Behavioral effects noted for survivors were initial hyperexcitability followed by apathy and weakness which persited the 14-day observation period.

Applicant's summary and conclusion

Interpretation of results:
Toxicity Category IV
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The acute oral LD50 of cesium hydroxide in albino rats was determined to be 1026 mg/kg bw.
Executive summary:

In an acute oral toxicity study, groups of 10 fasted male albino rats were given a single oral dose of cesium hydroxide in water at 6 different doses and observed for 14 days.

All deaths occurred within the first 72 h after dosing. Clinical signs were increased respiration rate, ruffled fur, eye closing and huddling together. A bloody nasal exudate was noted in several animals receiving the higher doses. Lethal and certain sublethal doses induced stomach and intestinal haemorrhage and adhesions of abdominal organs (stomach, pancreas, spleen, liver and small intestines). In the higher dose range, death was related to the degree of blockage of the gastrointestinal tract from the resultant adhesions and/or the leakage of the bloody fluid exudate into the peritoneal cavity.

Oral LD50 for males for cesium hydroxide = 1026 mg/kg bw (95% C.L: 929 - 1133).