Registration Dossier

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 based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
13 May - 08 July 1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP - Guideline study, tested with the source substance Fatty acids, C5-10, esters with pentaerythritol. 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)
Version / remarks:
adopted in 1983
Deviations:
no
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): only trade name given
- Physical state: pale yellow liquid
- Analytical purity: >98%
- Lot/batch No.: RMEST240
- Storage condition of test material: storage at room temperature in the dark

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories (UK Limited), Margate, Kent, UK
- Age at study initiation: 5-9 weeks for phase I (determination of the maximum tolerated dose) and 7-9 weeks for phase II (Micronucleus test) of the study
- Assigned to test groups randomly: Yes
- Housing: 5 per cage in mobile mouse cage racks, housed per sex
- Diet: Porton Combined Diet, ad libitum
- Water: filtered tap 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
Details on exposure:
The study consisted in two phases: in phase I the maximum tolerated dose (MTD) was determined, on the basis of lethalities or severe toxicity observed over a four-day observation period following a single intraperitoneal injection.
In phase II, male and female animals were weighed and given a single intraperitoneal injection of corn oil (vehicle control), cyclophosphamide (positive control) or test substance prepared in corn oil.

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 bw
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 bw 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 bw. This dose was selected as MTD.

TREATMENT AND SAMPLING TIMES: 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, 1000 erythrocytes were counted to determine the percentage of polychromatic erythrocytes in the total erythrocyte population.

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 wether 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
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
No statistically or biologically significant increases in the incidence of micronucleated polychromatic erythrocytes over the vehicle control values were seen in either sex at either of the sampling times.
Comparison of the percentage of polychromatic erythrocytes showed no significant differences between the female animals treated with the vehicle control or with the test material. A small, but significant decrease was, however, noted in male mice treated with the test material at 5000 mg/kg bw. This small decrease is, however, considered not to be statistically significant compared to the concurrent control values.
The positive control induced stastistically significant and biologically meaningful increases in micronucleated polychromatic erythrocytes, compared to the vehicle control values, thus demonstrating the sensitivity of the test system to a known clastogen.

Any other information on results incl. tables

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

 

Table 1: 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

 

Table 2: Females

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 ± Standard Deviation at two sampling times. n=5

 

Table 3: 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

 

Table 4: 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

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative