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Toxicological information

Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well performed OECD and GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report Date:
1986

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Sesame oil
Doses:
1600, 1800, 2000, 2240, 2500, 4000 mg/kg bw
No. of animals per sex per dose:
5
Control animals:
no

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LD50
Effect level:
2 280 mg/kg bw
Sex:
female
Dose descriptor:
LD50
Effect level:
1 930 mg/kg bw
Sex:
male/female
Dose descriptor:
LD50
Effect level:
2 070 mg/kg bw
Mortality:
4000 mg/kg bw: male: 5/5 female: 5/5
2500 mg/kg bw: male: 3/5 female: 3/5
2240 mg/kg bw: male: 3/5 female: 5/5
2000 mg/kg bw: male: 1/5 female: not tested
1800 mg/kg bw: male: not tested female: 2/5
1600 mg/kg bw: male: not tested female: 1/5
Clinical signs:
- Crouched position
- Bristled fur
- Retracted flanks
- Reduced spontaneous acitivity
- Blood-coloured incrusted eye lids
- Blood-coloured incrusted snouts
- Reduced breathing frequency
- Irregular breathing
- Intermittent breathing
- Long-legged walking
- Creeping forward motion
- Reduced or negative corneal and startle reflexes, reduced catch reflexes
- Drowsiness
- Lateral or ventral position
- Narcosis
- Symptoms were reversible within 7d p.a.
Body weight:
- Weight gain was not reduced except for one male rat from the 2240mg/kg group; probably caused by an injured snout
Gross pathology:
- Blood in the lung
- Liver: dark discoloration
- Sample material in stomach and small intestine
- Fully loaded bladder

Applicant's summary and conclusion

Interpretation of results:
harmful
Remarks:
Migrated information Criteria used for interpretation of results: expert judgment
Conclusions:
Acute oral toxicity testing of Benzimidazolon resulted in LD50 values of:
male and female rats (combined): 2070 mg/kg bw
male rats: 2280 mg/kg bw
female rats: 1930 mg/kg bw = most sensitive response

Executive summary:

Acute oral toxicity testing of Benzimidazolon resulted in LD50 values of

  • male and female rats: 2070 mg/kg bw
  • male rats: 2280 mg/kg bw
  • female rats: 1930 mg/kg bw

Clinical signs for intoxication were unspecific and comprised impairment of breathing, locomotor system, reflexes and conciousness. Furthermore, blood-crusted snouts, eye lids were observed. Ventral and lateral positions were observed, also narcosis. Within 7d p.a. the observed effects were reversible. Lethality was observed up to 5d p.a.

Gain of body weight was not affected by the test compound. One male rat from the 2240 mg/kg group showed reduced weight gain, probably caused by an injured snout.

Gross pathological findings of the deceased animals comprised: blood in the lung, dark discoloured liver, sample material in stomach and small intestine, and a fully loaded bladder.

The LD50 value of 1930 mg/kg bw for female rats represents the most sensitive response in this study.