Formamide

Acute Toxicity: oral

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

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1963

Report date:

1963

Reference 2

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

Test material information

Constituent 1

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).