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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
May 13th, 1992 - July 08th, 1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP - Guideline study, tested with the source substance CAS 68424-31-7. According to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Remarks:
: Few details on test compound
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: pale yellow liquid
- Analytical purity: >98%
- Lot/batch No.: RMEST240

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding , Margate, Kent, UKLaboratories
- Age at study initiation: 5-9 weeks for phase I and 7-9 weeks for phase II of the study
- Assigned to test groups randomly: Yes
- Housing:5 per cage in mobile mouse cage racks
- Diet: ad libitum
- Water: ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-23
- Humidity (%): 40-70
- Air changes (per hr): 25
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- Vehicle(s)/solvent(s) used: corn oil
- Amount of vehicle (if gavage or dermal): 10 ml/kg
- Lot/batch no. (if required): Y00790/004
Details on exposure:
Route = intraperitoneal

Dosing solutions of the test material were prepared in corn oil, the cyclophosphamide was prepared in physiological saline. The vehicle control, the test substance or cyclophosphamide was administered as a single intraperitoneal injection.
Duration of treatment / exposure:
Single dose
Frequency of treatment:
Single dose
Post exposure period:
24 h and 48 h
Doses / concentrations
Remarks:
Doses / Concentrations:
5000 mg/kg
Basis:
nominal conc.
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide
- Route of administration: i.p.
- Doses / concentrations: 65 mg/kg in physiological saline

Examinations

Tissues and cell types examined:
Monochromatic and polychromatic erythrocytes
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION:
No deaths or severe adverse effects occurred in Phase I of the study with doses up to 5000 mg/kg. This dose was selected as MTD.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): 24 h and 48 h after dosing


DETAILS OF SLIDE PREPARATION: Bone Marrow smears were stained with polychrome methylene blue and eosin


METHOD OF ANALYSIS: 1000 polychromatic erythrocytes were evaluated for micronuclei per slide. In addition, 1000erythrocytes were counted to determine the percentage of polychromatic erythrocytes in the total erythrocyte population.


OTHER:
Evaluation criteria:
Increase in the incidence of micronucleated polychromatic erythrocytes in any sex or at any time point.
Percentage of polychromatic erythrocytes.
Statistics:
The incidence of micronucleated polychromatic erythrocytes and percentage of polychromatic erythrocytes in the erythrocyte sample were considered by analysis of variance regarding each combination of sampling time, dose level and sex as a separate group. Results were examined to determine weather any differences between vehicle control and test substance treated groups were consistent between sexes and across sampling times.
Each group mean was compared with the vehicle control group mean at the corresponding sampling time using a one-sided Student´s t-test based on the error mean square in the analysis.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Remarks:
except for a small but significant decrease of polychromatic erythrocytes in male mice at 5000 mg/kg
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid

Any other information on results incl. tables

Mean incidence of micronucleated polychromatic erythrocytes/1000 polychromatic erythrocytes ±SD at two sampling times. n=5

 

Males

Group

Compound

Dose

Mean Incidence

24 h

48 h

11

Vehicle control

(corn oil)

10 ml/kg

0.8 ± 0.8

1.0 ± 1.2

12

Cyclophosphamide

65 mg/kg

24.4 ± 6.0

 

13

Test substance

5000 mg/kg

0.6 ± 0.6

0.4 ± 0.6

 

Female

Group

Compound

Dose

Mean Incidence

24 h

48 h

11

Vehicle control

(corn oil)

10 ml/kg

0.2 ± 0.5

1.4 ± 1.1

12

Cyclophosphamide

65 mg/kg

18.4 ± 7.3

 

13

 Test substance

5000 mg/kg

0.4 ± 0.9

0.4 ± 0.9

 

 

Mean percentage of polychromatic erythrocytes ±SD at two sampling times. n=5

 

Males

Group

Compound

Dose

Mean Incidence

24 h

48 h

11

Vehicle control

(corn oil)

10 ml/kg

48.0 ± 5.6

44.3 ± 7.5

12

Cyclophosphamide

65 mg/kg

41.4 ± 4.4

 

13

 Test substance

5000 mg/kg

42.2 ± 7.0

43.3 ± 1.9

 

Female

Group

Compound

Dose

Mean Incidence

24 h

48 h

11

Vehicle control

(corn oil)

10 ml/kg

41.9 ± 4.8

41.9 ± 1.7

12

Cyclophosphamide

65 mg/kg

45.9 ± 3.49

 

13

 Test substance

5000 mg/kg

46.5 ± 5.8

48.0 ± 5.2

Under the conditions tested, the test substance is not clastogenic in the mouse marrow micronucleus test.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative