2,6-difluorobenzamide

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sep - Oct 1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Non-GLP, near guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,6-difluorobenzamide

EC Number:

241-972-8

EC Name:

2,6-difluorobenzamide

Cas Number:

18063-03-1

Molecular formula:

C7H5F2NO

IUPAC Name:

2,6-difluorobenzamide

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Batch number: 722.35
ST number: ST86/206
Characterisation: no purity data available- commercial sample
Appearance: white powder

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River U.K., Ltd.
- Age at study initiation: 9 to 11 weeks
- Fasting period before study: animals were fasted overnight (18 hours)
- Weight at study initiation: 190 g (males) and 138 g (females)
- Housing: single sex groups of 2-3 in cages with stainless-steel wire-mesh floors and tops; each cage measured 38 x 25 x 18 cm
- Diet: PRD (Labsure animal Foods, Dorset, UK), ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

DMSO

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 50% in DMSO (m/v)

Doses:

780-3200 mg/kg bw

No. of animals per sex per dose:

780 mg/kg bw: 4
1250 mg/kg bw: 8
1500 mg/kg bw: 4
2000 mg/kg bw: 8
2500 mg/kg bw: 4
3200 mg/kg bw: 4

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days;
- Frequency of observations and weighing: Observations were recorded three times a day for the first three days and daily thereafter. The initial (i.e. day 1), day 7 and day 14 body weights were recorded;
- Necropsy of survivors performed: no;
- Other examinations performed: clinical signs and body weight.

Statistics:

prohibit analyis

Results and discussion

Effect levels

Effect levels 1

Sex:

male

Dose descriptor:

LD50

Effect level:

2 576 mg/kg bw

Based on:

test mat.

Remarks on result:

other: given the disparity in response between males and females, a combined LD50 values is not quoted

Effect levels 2

Sex:

female

Dose descriptor:

LD50

Effect level:

1 075 mg/kg bw

Based on:

test mat.

Remarks on result:

other: given the disparity in response between males and females, a combined LD50 values is not quoted

Mortality:

780 mg/kg bw: males: 0/4; females: 0/4
1250 mg/kg bw: males: 0/8; females: 6/8
1500 mg/kg bw: males: 0/4; females: 4/4
2000 mg/kg bw: males: 1/8; females: 8/8
2500 mg/kg bw: males: 1/4; females: 4/4
3200 mg/kg bw: males: 4/4; females: 4/4

Clinical signs:

other: The incidence and duration of clinical signs were dose-related. The commonest clinical signs seen indicated a neurological action since they included gait and posture abnormalities and prostration, the sequela to the latter being coma in some cases.

Gross pathology:

Not investigated.

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 median lethal dose (LD50) of the test item in female rats was calculated to be 1075 mg/kg bw and in male rats 2576 mg/kg bw.

Executive summary:

The acute oral toxicity of the test substance was investigated in Fischer 344 rats. The test substance was administered orally by gavage at 780, 1250, 1500, 2000, 2500 and 3200 mg/kg bw. Animals were subjected to observations and determination of the body weight. Mortality occurred at concentrations from 1250 up to 3200 mg/kg bw in females and from 2000 up to 3200 mg/kg bw in males. The incidence and duration of clinical signs were dose-related. The commonest clinical signs seen indicated a neurological action since they included gait and posture abnormalities and prostration, the sequela to the latter being coma in some cases. All surviving animals had gained weight relative to their day 1 bodyweights by the end of the 14 day observation period.

The acute oral median lethal dose (LD50) of the test item in female rats was calculated to be 1075 mg/kg bw and in male rats 2576 mg/kg bw.