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Toxicological information

Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
symptoms not described; no necropsy; purity of test substance not given

Data source

Reference
Reference Type:
publication
Title:
Toxicity of formaldehyde in experimental animals
Author:
Tsuchiya K, Hayashi Y, Onodera M, Hasegawa T
Year:
1975
Bibliographic source:
Kefo J Med 24: 19-37

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
yes
Remarks:
(symptoms not described; no necropsy)
GLP compliance:
no
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
Authors used a) formalin (37% aqueous solution stabilized with 10% methanol) or b) paraformaldehyde (polymer of formaldehyde) for preparation of solutions (presumably water used as solvent).
Purity: Special grade in a) and b)
No further details

Test animals

Species:
rat
Strain:
Wistar
Sex:
male
Details on test animals and environmental conditions:
100-200 g body weight at initiation; 5 rats per cage; solid feed; temperature 18-20°C

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: presumably water
Details on oral exposure:
- Concentration in vehicle: 1) 2% and 2) 4%
- Total volume applied
Max. 33 mL/kg bw in 1) at a dose of 675 mg/kg bw
In 2) max. 28.5 mL/kg bw at a dose of 1140 mg/kg bw
Doses:
230, 300, 400, 520, 675, 875 mg/kg bw (2% solution)
400, 520, 675, 875, 1140 mg/kg bw (4% solution)
No. of animals per sex per dose:
6-16 males per dose
Control animals:
no
Details on study design:
- Postexposure period:
1 week, but surviving rats lived until the experiments were finished (3 experiments performed in at least 3 weeks) indicating only early deaths.
- Examinations
Only mortality data given
Statistics:
Method of determination of LD50: Litchfield method

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LD50
Effect level:
460 mg/kg bw
95% CL:
330 - 650
Remarks on result:
other: 2% formalin
Sex:
male
Dose descriptor:
LD50
Effect level:
832 mg/kg bw
95% CL:
617 - 965
Remarks on result:
other: 4% formalin
Sex:
male
Dose descriptor:
LD50
Effect level:
550 mg/kg bw
95% CL:
420 - 715
Remarks on result:
other: 2% paraformaldehyde
Sex:
male
Dose descriptor:
LD50
Effect level:
710 mg/kg bw
95% CL:
550 - 910
Remarks on result:
other: 2% paraformaldehyde
Sex:
male
Dose descriptor:
LD50
Effect level:
640 mg/kg bw
95% CL:
551 - 742
Remarks on result:
other: 4% paraformaldehyde
Mortality:
Rats died in most cases within 24 h after application (no further details).
Clinical signs:
No data
Body weight:
No data
Gross pathology:
No data

Any other information on results incl. tables

Mortality rates in male Wistar rats after oral application of formaldehyde

2% formaldehyde

Formalin solutions

Paraformaldehyde solutions

Dose in mg/kg bw

Mortality

Dose in mg/kg bw

Mortality

675

7/7

675

5/8

520

3/7

520

4/8

400

1/6

400

2/8

300

1/7

300

1/8

230

0/7

230

1/8

875

9/9

675

4/9

520

2/9

400

0/9

300

0/9

4% formaldehyde

Formalin solutions

Paraformaldehyde solutions

Dose in mg/kg bw

Mortality

Dose in mg/kg bw

Mortality

1140

13/16

875

11/16

875

13/16

675

8/16

675

9/16

520

0/16

520

2/16

400

0/16

400

3/16

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Conclusions:
The mean oral LD50 value of five independent experiments in male Wistar rats is 640 mg/kg bw.
Executive summary:

The study is comparable to OECD 401 with accepatable restrictions (symptoms not described; no necropsy; purity of test substance not given).

Male Wistar rats (n= 6 -16) were gavaged with formalin or paraformaldehyde solution in water at concentrations of 2 or 4 %. The range of LD50 values was between 460 and 830 mg/kg bw. There is no significant difference between the paraformaldehyde and the formalin solution, nor any significant difference concerning the concentration (2 or 4% solutions).
The mean oral LD50 value of five independent experiments in male Wistar rats is 640 mg/kg bw.