Registration Dossier

Administrative data

Endpoint:
in vivo mammalian cell study: DNA damage and/or repair
Remarks:
COMET assay
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
COMET assay agreed as further study following ECHA discussions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 489 (In vivo Mammalian Alkaline Comet Assay)
Version / remarks:
2016
GLP compliance:
yes (incl. certificate)
Type of assay:
mammalian comet assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
Identification: Formaldehyde, reaction products with ethylenediamine
CAS Number: 84066-92-2
Physical state/Appearance: Clear colorless liquid
Batch: LC-354-124
Purity: 93% (water 65.6%), ie ca 35%
Expiry Date: 01 January 2019
Storage Conditions: Room temperature in the dark
Intended use/Application: Hydrogen sulphide scavenger

Test animals

Species:
rat
Strain:
Wistar
Details on species / strain selection:
Wistar Han™ (HsdRCCHan™WIST)
Sex:
male
Details on test animals and environmental conditions:
The animals were housed in groups of up to five in solid-floor polypropylene cages with woodflake bedding. Free access to mains drinking water and food (Envigo Teklad 2014 Rodent Pelleted Diet) was allowed throughout the study.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Water
Details on exposure:
Double dose of maximum 660 mg/kg and killed 4 hours after second dose.
Duration of treatment / exposure:
Two doses,
Sampling 4 hours after second dose
Frequency of treatment:
All animals were dosed twice 24 hours apart
Post exposure period:
4 hours
Doses / concentrationsopen allclose all
Dose / conc.:
165 mg/kg bw/day (nominal)
Dose / conc.:
330 mg/kg bw/day (nominal)
Dose / conc.:
660 mg/kg bw/day (nominal)
No. of animals per sex per dose:
Seven
Control animals:
yes, concurrent vehicle
other: Positive control group
Positive control(s):
N-Nitroso-N-methylurea (MNU)

Examinations

Tissues and cell types examined:
Samples of liver, glandular stomach, duodenum and gonadal somatic cells (testes) were obtained from each animal.
Bone marrow was also sampled from the animals of the vehicle control group and the MTD dose group for slide preparation.
Details of tissue and slide preparation:
Sub-samples of the liver, glandular stomach, duodenum and gonadal somatic cells (testes) were taken from the vehicle control animals and the dose group animals and preserved in 10% buffered formalin for possible histopathology investigations. Assessment of cytotoxicity by histopathology is conducted if the results from the Comet assay, or other observations, suggest cytotoxicity may be confounding the interpretation of the Comet assay.

Results and discussion

Test results
Key result
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
In the range finding test, there was one death at 880 mg/kg, so the top dose of 660 mg/kg was used with hunched posture, lethargy, ataxia, ptosis and pilo-erection with significant weight loss between the start of the test and its death. Necropsy revealed hemorrhaging along the limiting ridge of the stomach.

Applicant's summary and conclusion

Conclusions:
The test item, Formaldehyde, reaction products with ethylenediamine did not induce any increases in the percentage (comet) tail intensity or median percentage tail intensity in the liver, glandular stomach, duodenum or gonadal somatic cells (testes) and therefore the test item was considered to be unable to induce DNA strand breakage to these tissues in vivo, under the conditions of the test.