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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
in vivo mammalian cell study: DNA damage and/or repair
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 March 2022 to 20 Dec 2022
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
DECISION ON SUBSTANCE EVALUATION: SEV-D-2114534345-52-01/F

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2022
Report date:
2022

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 489 (In vivo Mammalian Alkaline Comet Assay)
Deviations:
yes
Remarks:
All deviations are not considered to affect the accuracy, integrity, or validity of the study.
GLP compliance:
yes (incl. QA statement)
Type of assay:
mammalian comet assay

Test material

Constituent 1
Chemical structure
Reference substance name:
N,N-diethylhydroxylamine
EC Number:
223-055-4
EC Name:
N,N-diethylhydroxylamine
Cas Number:
3710-84-7
Molecular formula:
C4H11NO
IUPAC Name:
N,N-diethylhydroxylamine
Test material form:
liquid
Details on test material:
Purity (%): 99.32 (DEHA content)
Expiry Date: 03 February 2023
Specific Gravity: 0.869
Dissociation constant (pKa): 12.88

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
Male and female range finding experiment. Only male used for main experiment.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Solutions of N,N-diethylhydroxylamine were prepared in purified water.
- Ethyl Methanesulfonate, was used as the positive control compound. A solution was prepared using purified water at a concentration of 20 mg/mL just prior to administration.
- Dose volume of DEHA solutions and vehicle control: 15 mL/kg. Dose volume of the positive control group: 10 mL/kg.
Details on exposure:
All animals in the vehicle control and N,N-diethylhydroxylamine-treated groups were dosed orally using a dose volume of 15 mL/kg

All main comet experiment formulations were prepared on the first day of dosing, stored at 2-8℃ and used within 24 hours.
Duration of treatment / exposure:
N,N-diethylhydroxylamine was administered on two occasions approximately 21 hours apart.
Frequency of treatment:
Two occasions approximately 21 hours apart.
Post exposure period:
Tissue sampling occurred approximately 3 hours after the second dose.
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day
Remarks:
Vehicle
Dose / conc.:
437.5 mg/kg bw/day
Dose / conc.:
875 mg/kg bw/day
Dose / conc.:
1 750 mg/kg bw/day
No. of animals per sex per dose:
6 male per dose
Control animals:
yes
Positive control(s):
EMS - Ethyl methanesulfonate
- A solution was prepared using purified water at a concentration of 20 mg/mL just prior to administration.
- Route of administration: oral
- Doses / concentrations: 200 mg/kg/day

Examinations

Tissues and cell types examined:
Sections of the liver, duodenum, stomach and testes
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: Male animals only were selected to test up to the higher possible dosage

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Single cell suspensions were prepared using a tissue specific method

DETAILS OF SLIDE PREPARATION:
For each tissue type an appropriate dilution was prepared.
These were stored at 2 - 8ºC overnight prior to electrophoresis

METHOD OF ANALYSIS: Electrophoresis; Microscopic Examination.
Evaluation criteria:
The following criteria were applied for assessment of assay acceptability:
- The concurrent vehicle control is considered comparable to the laboratory historical vehicle control data for each tissue.
- The positive control should induce responses that are compatible with those generated in the historical positive control database and produce a statistically significant increase compared with the concurrent vehicle control.
- Adequate numbers of cells and doses have been analysed.
- The high dose is considered to be the MTD, the maximum recommended dose or the maximum practicable dose.

For valid data, the test article will be considered to induce DNA damage if:
1. At least one of the test doses exhibits a statistically significant increase in tail intensity, in any tissue, compared with the concurrent vehicle control
2. The increase is dose related in any tissue
3. The increase exceeds the laboratory’s historical control data for that tissue.
The test article will be considered positive in this assay if all of the above criteria are met.
The test article will be considered negative in this assay if none of the above criteria is met and target tissue exposure has been confirmed.

Results which only partially satisfy the criteria will be dealt with on a case-by-case basis. Biological relevance will be taken into account, for example comparison of the response against the historical control data, consistency of response within and between dose levels and any confirmatory experiments. Analysis of additional cells from vehicle and / or treated animals or further experimental work may be deemed necessary to aid evaluation of the data.

A positive response will be based on scientific judgement and will include analysis of related, concurrent cytotoxicity information (such as hedgehog assessment, histopathological changes and any clinical pathology results) and the historical control data. Positive results at clearlycytotoxic dose levels will be interpreted with caution and
Statistics:
Significant differences between the groups compared were expressed at the 5% (p<0.05) or 1% (p<0.01) level.

Results and discussion

Test results
Key result
Sex:
male
Genotoxicity:
negative
Toxicity:
not specified
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No mortalities were observed throughout the duration of the main comet experiment.
There was no effect on the stomach or duodenum of animals administered
N,N-diethylhydroxylamine at 437.5 mg/kg/day, or in the liver and testes at any concentration tested.

Applicant's summary and conclusion

Conclusions:
Liver
It is concluded that N,N-diethylhydroxylamine has not shown any evidence of causing an increase in DNA strand breaks in the liver of male Crl:CD(SD) rats when administered orally by gavage in this in vivo test procedure.

Duodenum
It is concluded that N,N-diethylhydroxylamine has shown evidence of causing an increase in DNA strand breaks in the duodenum of male Crl:CD(SD) rats at 875 and 1750 mg/kg/day only, when administered orally by gavage in this in vivo test procedure. However, due to the confounding presence of hedgehog cells and substantial evidence of cytotoxicity this is not considered to be genotoxic in nature.

Stomach
It is concluded that N,N-diethylhydroxylamine has shown evidence of causing an increase in DNA strand breaks in the stomach of male Crl:CD(SD) rats at 875 and 1750 mg/kg/day only, when administered orally by gavage in this in vivo test procedure. The damage observed is considered to be cytotoxic in nature, however, due to insufficient evidence of cytotoxicity at the 875 mg/kg/day dosage to provide a definitive conclusion, N,N-diethylhydroxylamine is considered unlikely to be genotoxic in nature.

Testes
It is concluded that N,N-diethylhydroxylamine has not shown any evidence of causing an increase in DNA strand breaks in the testes of male Crl:CD(SD) rats when administered orally by gavage in this in vivo test procedure.
Executive summary:

N,N-diethylhydroxylamine is considered unlikely to be genotoxic in nature.