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Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1963-01-30 through 1963-02-06
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions. Restriction: test substance purity not reported.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1963
Report date:
1963
Reference Type:
other: raw data
Title:
Unnamed
Year:
1963
Report date:
1963

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
yes
Remarks:
brief report; pre-guideline study
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Formamide
EC Number:
200-842-0
EC Name:
Formamide
Cas Number:
75-12-7
Molecular formula:
CH3NO
IUPAC Name:
formamide
Details on test material:
Formamide, degree of purity not reported.

Test animals

Species:
rat
Strain:
other: Heigl
Sex:
male/female
Details on test animals or test system and environmental conditions:
no data

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Doses:
ca. 227, 1813, 3626, 4532, 5665, 7251 mg/kg bw (0.2, 1.6, 3.2, 4.0, 5.0, 6.4 ml/kg bw)
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
Groups of 5 male and 5 female Heigl rats per dose level were applied an aqueous solution of the test substance by gavage. 
Body weights of the rats were in the range of 155-248 g (males) and 142-190 g (females). 

Terst substance concentrations of 2%, 20% or 30% (v/v) were used.  The animals were administered 0.2, 1.6, 3.2, 4.0, 5.0, and 6.5 ml of the pure test substance (ca. 227, 1813, 3626, 4532, 5665, and 7251 mg/kg bw, respectively, calculated with a density of 1.133 g/cm3). 
Animals of the two lowest dose groups were sacrificed at 7 days after dosing. 
The other animals were sacrificed after a 14-day observation period.
Statistics:
Graphical determination of the LD50-value

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LD50
Effect level:
ca. 5 325 mg/kg bw
Remarks on result:
other: after 14 days
Mortality:
Deaths occurred in group sat 3600 - 7200 mg/kg bw. Late deaths were observed, i.e. animals died within up to 9 days after dosing. Details are reported below.
Clinical signs:
other: No signs of toxicity and no deaths were observed at the two lowest dose levels; these animals were sacrificed after an observation period of 7 days (higher dose groups: observation period of 14 days). In the other groups, clinical signs were observed from
Gross pathology:
Autopsy revealed a poor nutritional state (anorexia) in animals that died. Organ pathology revealed no specific findings.

Any other information on results incl. tables

Mortality:

Values reported in the original reports:

LD50 = 5.1 (4.36-5.96) mL formamide/kg bw after 7 days.
LD50 = 4.7 mL formamide/kg 
bw (ca. 5325 mg/kg bw) after 14 days.

 

 

Dose

Test substance concentration

deaths after

[mL/kg]

[mg/kg]

[%]

1 h

24 h

48 h

7 d

14 d

0.2

277

2

0/10

0/10

0/10

0/10

0/10

1.6

1813

20

0/10

0/10

0/10

0/10

0/10

3.2

3626

30

0/10

0/10

0/10

0/10

1/10

4.0

4532

30

0/10

0/10

0/10

1/10

2/10

5.0

5665

30

0/10

0/10

0/10

4/10

6/10

6.4

7251

30

0/10

2/10

5/10

9/10

10/10

 

 

Applicant's summary and conclusion

Executive summary:

Conclusion:

 

The oral LD50was approximately 5325 mg/kg bw in male and female Heigl rats (5 animals/sex/dose; observation period 14 days) receiving formamide as aqueous solutions by oral gavage in a pre-guideline study that was essentially conducted similar to the OECD No. 401 Guideline. Clinical signs (and mortalities) were seen in groups at 3600 mg/kg bw and above, and included poor general health state, ruffled fur, irregular respiration, apathy, atony, lateral recumbent position and reduced food consumption. Surviving rats appeared normal within 12-14 days after dosing. Late mortality up to 9 days after dosing were noted (BASF, 1963).