N,N-dimethylformamide

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented report which meets basic scientific principles.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1977

Report date:

1977

Reference 2

Reference Type:

publication

Title:

OECD SIDS Dimethylformamide, Final April 2004

Author:

OECD

Year:

2004

Bibliographic source:

OECD SIDS Dimethylformamide

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

not specified

Principles of method if other than guideline:

- Principle of test: Repeated dose 28-day oral gavage study in rats.
- Short description of test conditions: Sprague-Dawley rats received DMF at dose levels of about 238, 475, 950 and 1900 mg/kg bw/day by gavage on 5 days/week during four weeks.
- Parameters analysed / observed: Clinical signs, body weights and findings by necropsy were recorded.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dimethylformamide

IUPAC Name:

Dimethylformamide

Constituent 2

Reference substance name:

N,N-dimethylformamide

EC Number:

200-679-5

EC Name:

N,N-dimethylformamide

Cas Number:

68-12-2

Molecular formula:

C3H7NO

IUPAC Name:

N,N-dimethylformamide

Details on test material:

- Name of test material (as cited in study report): N,N-dimethylformamide

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: WIGA, Sulzfeld, Germany
- Age at study initiation: 32 days
- Weight at study initiation: male: 104-120 g; female: 104 - 122 g
- Housing: 3 per cage
- Diet: Altromin-R, Altrogge, Germany ad libitum
- Water: tap water ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 55 ± 5
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

no details given

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

28 days

Frequency of treatment:

5 d/w

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

238 mg/kg bw/day (nominal)

Remarks:

250 µL/kg
Basis: nominal in water

Doses / concentrations 2

Dose / conc.:

475 mg/kg bw/day (nominal)

Remarks:

500 µL/kg
Basis: nominal in water

Doses / concentrations 3

Dose / conc.:

950 mg/kg bw/day (nominal)

Remarks:

1000 µL/kg
Basis: nominal in water

Doses / concentrations 4

Dose / conc.:

1 900 mg/kg bw/day (nominal)

Remarks:

2000 µL/kg
Basis: nominal in water

No. of animals per sex per dose:

10

Control animals:

other: aqua bidest

Details on study design:

no information given

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: twice weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 10 days before the start of the study and directly before the last substance administration.
- How many animals: all
- Parameters examined: mean cell haemoglobin concentration, haemoglobin, erythrocytes, haematocrit, thrombocytes, leucocytes, differential count, mean cell volume, mean cell haemoglobin.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 10 days before the start of the study and direclty before the last substance administration.
- How many animals: all
- Parameters examined: urea, chloride, creatinine, calcium, glucose total, bilirubin, albumin, phosphorus (as phosphate), total protein, lipids, sodium, potassium, carbon dioxide, alkaline phosphatase activity, glutamate-pyruvat transfaminase activity.

URINALYSIS: Yes
- Time schedule for collection of urine: day 21 or 22
- Parameters examined: pH, protein, glucose, bilirubin, sediment.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes: heart, lung, thyroid, stomach, duodenum, jejunum, ileum, mesenteric lymph nodes, liver, pancreas, spleen, kidneys, adrenals, urinary bladder, testes and ovaries and brain.

Other examinations:

Body weight and organ weights of heart, liver, kidneys, spleen, thyroid, adrenals, testes, uterus and ovary were determined.

Statistics:

Statistical calculations (t-Test; x2-Test) were done for clinical, pathological and clinical chemistry data as well as for data from haematology and urinalysis.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

The animals in the highest dose group showed piloerection, apathy, anaemia, dyspnoea, hyperthermia, lateral position.

Mortality:

mortality observed, treatment-related

Description (incidence):

At the highest dose group all animals died, mostly during the first 5 days of substance application. The animals in the highest dose group showed piloerection, apathy, anaemia, dyspnoea, hyperthermia, lateral position.
At 950 mg DMF/kg the general state of health was reduced (in male animals already beginning in study week 1, in female animals at the end of study week 3). 4 male animals (on study days 7, 8, 14 and 19) and one female animal (after 15 substance applications) died.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

The animals in the highest dose group showed reduced body weight gain already after the first treatment. At 950 mg DMF/kg significantly reduced body weight when compared to the controls (at the end of the study for male animals 28 % lower, and for female animals 21 % lower than control). At 475 mg/kg significantly reduced body weight when compared to the control animals (14.6 % lower than controls) were seen.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

The animals in the highest dose group showed reduced food consumption already after the first treatment. At 950 mg DMF/kg the animals showed significantly reduced food consumption (up to 36 % reduced in the males and up to 40 % reduced in the females). At 238 and 475 mg/kg reduced food consumption in the male animals were seen.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

950 mg/kg: 1 male and 2 females showed an extreme decrease in thrombocytes and the males an increase in segmented granulocytes and decrease in lymphocytes.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

At 950 mg DMF/kg hepatic damage was represented by changes in clinical chemistry values (increased total bilirubin, increased enzyme values, i.e. GPT, AP) and disturbances in kidney function were represented by elevated urea (in 2 of 9 female animals) and creatinine values (in all animals of the 950 mg/kg dose group).

Urinalysis findings:

no effects observed

Description (incidence and severity):

No abnormalities

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Relative liver weights were increased in both sexes' and relative kidney weights were increased in the male animals at 950 mg/kg. At 238 and 475 mg/kg in both sexes increased relative liver weights and in the males increased relative kidney weights were observed, however without histopathological correlates.

Gross pathological findings:

not specified

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Histologically an acute to subacute haemorrhagic liver dystrophy with necrosis was found in the animals of 950 mg/kg and the highest dose group.

Histopathological findings: neoplastic:

not examined

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

238 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no significant effects

Remarks on result:

not determinable due to absence of adverse toxic effects

2

Dose descriptor:

LOAEL

Effect level:

475 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: reduced body weight

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

The repeated application of dimethylformamide in doses from 950 mg/kg onwards leads to distinct acute haemorrhagic liver dystrophy with necrosis. Females were in general more tolerant to dimethylformamide.

Applicant's summary and conclusion

Conclusions:

NOAEL of 238 mg/kg bw and LOAEL of 475 mg/kg bw were established for both sexes.

Executive summary:

Study design

This non-GLP in vivo study was conducted similar to OECD TG 407 (Repeated Dose 28-Day Oral Toxicity in Rodents). In the present study, Sprague-Dawley rats received 250, 500, 1000 and 2000 µL N,N-dimethylformamide /kg bw (about 238, 475, 950 and 1900 mg/kg bw/day) by gavage on 5 days/week during four weeks.

Results

In the highest dose group all animals died, mostly at the beginning of the study. At 1000 µL/kg bw/day all animals affected by reduced food consumption and reduced body weight, males already at the beginning, females at the end of the study. Hepatic injury was characterized by changes in clinical chemistry values, e.g. increased enzyme activities. Relative liver weights were increased in both sexes. Histological examination revealed an acute to subacute haemorrhagic liver dystrophy with necrosis in both sexes in the two high dose groups. Disturbances in kidney function were characterized by elevated urea (females) and creatinine values, the latter one in both sexes. Relative kidney weights were increased in the males. At 250 and 500 μL/kg bw/day reduced food consumption in the males and at 500 μL/kg bw/day reduced body weight was observed in the males. For the observation of increased relative liver weights in both sexes and of increased relative kidney weights in the males no histopathological correlate was found.

Conclusion

NOAEL of 238 mg/kg bw and LOAEL of 475 mg/kg bw were established for both sexes.