Imidazole

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 1956

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was performed prior to the implementation of OECD Guidelines and GLP, but is in compliance with the principles described in OECD Guideline 401.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1956

Report date:

1956

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

not applicable

Principles of method if other than guideline:

Study was performed prior to the implementation of OECD Guidelines and GLP, but is in compliance with the principles described in OECD Guideline 401.

GLP compliance:

no

Remarks:

test predated GLP

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Imidazole

EC Number:

206-019-2

EC Name:

Imidazole

Cas Number:

288-32-4

Molecular formula:

C3H4N2

IUPAC Name:

1H-imidazole

Details on test material:

Imidazole (CAS: 288-32-4), white crystalline powder, purity ca. 100%
The Test Substance was prepared in aqueous medium to give a final concentration of 10% imidazole, pH 9.

Test animals

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

Young adult laboratory rats were purchased from a breeder. The source and strain of the animals were not documented.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

Concentration in vehicle: 10%

Doses:

500, 700, 1000, 1260, 2000, 4000, 5000 mg/kg bw

No. of animals per sex per dose:

(Dose in mg/kg bw : no of animals):
5000 : 1
4000 : 1
2000 : 5
1260 : 5
1000 : 5
700 : 5
500 : 5

Control animals:

no

Details on study design:

In principle, the methods described in OECD Guideline 401 were used.
Young adult laboratory rats were purchased from a breeder and the source and strain of the animals were not specified.
Groups of up to 5 rats and dose were treated simultaneously by gavage with preparations of the test substance in a suitable vehicle.
The concentrations of these preparations were usually adjusted to achieve comparable volumes (i.e. 10 ml) per kg body weight.
Group-wise documentation of clinical signs was performed over the 7 day study period. Body weight was determined before
the start of the study only, as it was needed for determination of dose. The clinical signs and findings were reported in summary form.

Statistics:

On the basis of the observed lethality, the LD50 value was determined using a graphical evaluation of the dose
response curve on probability paper.

Results and discussion

Effect levels

Sex:

not specified

Dose descriptor:

LD50

Effect level:

ca. 970 mg/kg bw

Mortality:

All animals died when tested with 1200 mg/kg bw and above. 2/5 animals died at 1000 mg/kg bw and
1/5 rats were dead at 700 mg/kg bw, while all 5 rats survived 500 mg/kg bw. All animals died within 1 day after application.

Dose in mg/kg bw : no of animals that died/total no of animals:
5000 : 1/1
4000 : 1/1
2000 : 5/5
1260 : 4/5
1000 : 3/5
700 : 2/5
500 : 0/ 5

Clinical signs:

other: During acute toxicity studies signs observed in rats included convulsions, disequilibria, lateral posture, death within one day . Apathy, minor disequilibria, and accelerated respiration was noted in survivors.

Gross pathology:

No data

Applicant's summary and conclusion

Executive summary:

In a non-guideline acute oral toxicity study the LD50 in rats was determined to be 970 mg/kg bw.

The symptoms were described as convulsions and disequilibria with lateral posture.

Deaths occurred within one day. Apathy and accelerated respiration was noted in survivors.