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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2005
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study performed according to OECD guideline 474 and in compliance to GLP.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
2005
Report date:
2005
Reference Type:
other: Published secondary source
Title:
Unnamed
Year:
2006
Report date:
2006

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-(2,4-diaminophenoxy)ethanol dihydrochloride
EC Number:
266-357-1
EC Name:
2-(2,4-diaminophenoxy)ethanol dihydrochloride
Cas Number:
66422-95-5
Molecular formula:
C8H12N2O2.2ClH
IUPAC Name:
2-(2,4-diaminophenoxy)ethan-1-ol dihydrochloride
Details on test material:
Test item : 2,4-Diaminophenoxyethanol dihydrochloride
EC number : 266-357-1
Batch number : 0120022
Purity : >99.5%

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
-Source : Charles River Laboratories, Raleigh, North Carolina, USA
-Age at study initiation : ~9 weeks
-Weight at study initiation : 262-306g for males ; 181-227g for females
-Assigned to test groups randomly : Yes
-Housing : Singly after randomisation
-Diet : PMI certified rodent diet 5002, ad libitum
-Water : Tap water, ad libitum
-Acclimation period : Minimum of 5 days

ENVIRONMENTAL CONDITIONS
-Temperature : 64 to 79 deg F
-Humidity : 30 to 70%
-Air changes (per hour) : 10 or greater
-Photoperiod : 12 hour light/12 hour dark cycle

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Vehicle used : Water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS
The solutions were held for at least 15 minutes prior to dosing at room temperature, protected from light in a nitrogen atmosphere.

DIET PREPARATION
No information available.
Duration of treatment / exposure:
24 and 48 (highest dose group only) hours after treatment.
Frequency of treatment:
Once.
Post exposure period:
24 and 48 (highest dose group only).
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
375 mg/kg bw
Basis:
actual ingested
Remarks:
Doses / Concentrations:
750 mg/kg bw
Basis:
actual ingested
Remarks:
Doses / Concentrations:
1500 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
5-6/sex/dose
Control animals:
yes, concurrent vehicle
Positive control(s):
Positive Control : Cyclophosphamide

Examinations

Tissues and cell types examined:
Bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION
The highest dose chosen for the micronucleus assay was 1500 mg/kg bw, the estimated maximum tolerated dose.

TREATMENT AND SAMPLING TIMES
Animals received the test substance once by gavage. Sacrifice time : 24 and 48 (highest dose group only) hours after the treatment.

DETAILS OF SLIDE PREPARATION
Following centrifugation to pellet the marrow, the supernatant was removed by aspiration and portions of the pellet were spread on slides and air dried. The slides were fixed in methanol, stained in acridine orange and analysed under fluorescent microscopy.

METHOD OF ANALYSIS
Slides prepared from the bone marrow collected from five animals per group at the designated harvest timepoints were scored for micronuclei and the PCE to NCEcell ratio. The micronucleus frequency (expressed as percent micronucleated cells) was determined by analysing the number of micronucleated PCEs from at least 2000 PCEs per animal. The PCE : NCE ratio was determined by scoring the number of PCEs and NCEs observed while scoring at least 500 erythrocytes per animal. The criteria for the identification of micronuclei were those of Schmid (1976).
Evaluation criteria:
The test substance was classified as mutagenic if it induced either a dose-related increase or a clear increase in the number of micronucleated polychromatic erythrocytes in a single dose group. Statistical methods were used as an aid in evaluating the results. However, the primary point of consideration was the biological relevance of the results. The test substance was considered non-mutagenic if it failed to produce a biological relevant increase in the number of micronucleated polychromatic erythrocytes.
Statistics:
Assay data analysis was performed using an analysis of variance (Winer, 1971) on untransformed proportions of cells with micronuclei per animal and on untransformed PCE : NCE ratios when the variances were homogeneous. Ranked proportions were used for heterogeneous variances. If the analysis of variance was statistically significant (p<=0.05), a t-test (Dunnett, 1955; 1964) was used to determine which dose groups; if any, were statistically significantly different from the vehicle control.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
2,4-Diaminophenoxyethanol dihydrochloride induced signs of clinical toxicity at 1500 mg/kg bw. One animal treated at 1500 mg/kg was found dead. No statistically significant increases in micronucleus frequencies were observed in polychromatic erythrocytes (PCEs) from male and female rats at any dose of 2,4-diaminophenoxyethanol dihydrochloride examined. One male (48 hour timepoint) and one female (24 hour timepoint) at the 1500 mg/kg dose level had elevated micronucleus responses. However, the overall micronucleus responses were not statistically significant when compared with the concurrent vehicle control, and these isolated increases were considered to bear no biological relevance. No statistically significant decreases in the PCE:NCE ratios (an indicator of cytotoxicity) were observed with 2,4-diaminophenoxyethanol at doses up to 1500 mg/kg in either male or female rats. Although there were no indications of bone marrow toxicity, the oral bioavailability of 2,4-diaminophenoxyethanol dihydrochloride was evident by the clinical signs observed at 750 and 1500 mg/kg and death observed at 1500 mg/kg.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
2,4-Diaminophenoxyethanol dihydrochloride was considered negative in the rat bone marrow micronucleus test under the conditions of this assay.
Executive summary:

2,4 -Diaminophenoxyethanol dihydrochloride was investigated for the induction of micronuclei in the bone marrow polychromatic erythrocytes of rats. The study was performed according to OECD guideline 474 in compliance to GLP. Dose selection was based on a dose range finding assay. In the micronucleus assay, the test substance was formulated in water and administered once. The following dose levels of the test substance were investigated : 375, 750 and 1500 mg/kg bw (administered once by gavage). The animals (5 animals/sex/dose) were administered the test substance, vehicle control or positive control. 2,4-Diaminophenoxyethanol dihydrochloride induced signs of clinical toxicity at 1500 mg/kg bw. One animal treated at 1500 mg/kg was found dead. No statistically significant increases in micronucleus frequencies were observed in polychromatic erythrocytes (PCEs) from male and female rats at any dose of 2,4-diaminophenoxyethanol dihydrochloride examined. One male (48 hour timepoint) and one female (24 hour timepoint) at the 1500 mg/kg dose level had elevated micronucleus responses. However, the overall micronucleus responses were not statistically significant when compared with the concurrent vehicle control, and these isolated increases were considered to bear no biological relevance. No statistically significant decreases in the PCE:NCE ratios (an indicator of cytotoxicity) were observed with 2,4-diaminophenoxyethanol at doses up to 1500 mg/kg in either male or female rats. Although there were no indications of bone marrow toxicity, the oral bioavailability of 2,4-diaminophenoxyethanol dihydrochloride was evident by the clinical signs observed at 750 and 1500 mg/kg and death observed at 1500 mg/kg. 2,4-Diaminophenoxyethanol dihydrochloride was considered negative in the rat bone marrow micronucleus test under the conditions of this assay.