Registration Dossier

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:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted before GLP principles (1978). The study did not fully follow the requirements of current Guideline OECD 474, but was performed according to acceptable scientific principles. No concurrent positive controls were used. No information is available on purity of test substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1978
Report date:
1978

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: Boller K. & Schmid W. (1970); Schmid W. (1975)
Deviations:
not applicable
Principles of method if other than guideline:
Generally similar to OECD 474 with limited endpoints examined.
GLP compliance:
no
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Reaction mass of 1-phenyloctadecane-1,3-dione and phenylicosane-1,3-dione
EC Number:
915-316-2
Molecular formula:
C50H80O4
IUPAC Name:
Reaction mass of 1-phenyloctadecane-1,3-dione and phenylicosane-1,3-dione

Test animals

Species:
mouse
Strain:
Swiss
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: no data
- Age at study initiation: no data
- Weight at study initiation: no data
- Assigned to test groups randomly: no data
- Fasting period before study: no data
- Housing: no data
- Diet: no data
- Water: no data
- Acclimation period: no data



ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data


IN-LIFE DATES: no data

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: arachis oil
- Justification for choice of solvent/vehicle: no data
- Concentration of test material in vehicle: 40 and 100 mg/mL (suspension was obtrained at the highest dose)
- Amount of vehicle (if gavage or dermal): no data
- Type and concentration of dispersant aid (if powder): not applicable
- Lot/batch no. (if required): no data
- Purity:no data
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: no data

DIET PREPARATION: not applicable (gavage)
Duration of treatment / exposure:
Not applicable (sacrifice 6-hours after the second gavage)
Frequency of treatment:
Two gavage doses with an interval of 24 hours
Post exposure period:
6-hour before sacrifice
Doses / concentrations
Remarks:
Doses / Concentrations:
1000 and 2500 mg/kg b.w.
Basis:
other: nominal dose administered as gavage
No. of animals per sex per dose:
10 males/dose at both doses and 10 males for the negative control group (see Table 7.6.2/1).
Control animals:
yes, concurrent vehicle
Positive control(s):
No. Results were compared with those from known mutagens under similar conditions: benzene, benzo(a)pyrene; methylmethanesulphonate

Examinations

Tissues and cell types examined:
Femurs were dissected from each animal to remove the bone marrow in order to obtain cell suspension (see Table 7.6.2/2).
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: up to the highest obtainable suspension in the vehicle


TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):no data


DETAILS OF SLIDE PREPARATION: a drop of cell suspension was spread onto a slide to prepare a smear in the conventional manner. This smear is dried and stained by the MayGrunwald-Giemsa technique.


METHOD OF ANALYSIS: the stained smears were examined to determine the incidence of micronucleated cells per 2000 polychromatic erythrocytes/animal by observing 1000 polychromatic erythrocytes on a different slide. The mean is then established for these two readings.


OTHER: no data
Evaluation criteria:
A positive response is normally indicated by an increase in the incidence of micronucleated polychromatic erythrocytes for the treatment group compared with the concurrent negative control group.

ACCEPTANCE CRITERIA: no data
The sensitivity of the method was indicated by values obtained under the same experimental conditions and with the same strain of mice, for three knwon admininstered as gavage (benzene, benzo(a)pyrene, methylmethane).
Statistics:
No data.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
other: by comparison with known mutagen values obtained in previous studies under the same conditions
Additional information on results:
RESULTS OF RANGE-FINDING STUDY: no

RESULTS OF DEFINITIVE STUDY: see Table 7.6.2/3

Any other information on results incl. tables

                                         Table 7.6.2/3: Tissues and cells examined after 24-hour and 48-hour sampling time

Conditions

Negative control*

Low dose

(1000 mg/kg b.w.)

High dose

(2500 mg/kg b.w.)

Positive control

Number of cells evaluated

2000

2000

2000

2000

Sampling time (h)

6 hours

Ratio of erythrocytes

polychromatic / (normochromatic + polychromatic)

-

-

-

-

polychromatic with micronuclei / polychromatic

0.23

0.22

0.17

**

Normochromatic with micronuclei / normochromatic

-

-

-

-

                *Arachis oil

                **Values from known mutagens in similar conditions of test: Benzene: 1.31±0.44%;

Benzo(a)pyrene: 4.51%±0.60%;methylmethane sulfonate 1.76%

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Stearoylbenzoylmethane showed no evidence of causing chromosome damage or bone marrow cell toxicity at doses up to limit dose levels.
Executive summary:

Bone marrow micronucleus assay was conducted in Swiss mouse according to the micronucleus test. The study was conducted before mutagenic test guidelines and good laboratory guidelines (1978). Animals (10 males/test substance dose, 10 males for the negative control) were treated by gavage with Stearoylbenzoylmethane at 1000 and 2500  mg/kg bw (the highest obtainable suspension in Arachis oil) as two doses administered with an interval of 24 hours. Bone marrow cells were harvested at 6 hours post-treatment for all dose groups.
Ten males were treated by gavage with arachis oil as concurrent vehicle negative control group. Bone marrow cells were harvested at 6-hour post-treatment and 2000 cells per dose group were examined.

There were no signs of toxicity during the study, at doses up to and above the 2000 mg/kg limit dose specified in OECD 474. There was no increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow by comparison with results from negative control animals.

Under the conditions of the in vivo test, stearoylbenzoylmethane showed no evidence of causing chromosome damage or bone marrow cell toxicity.

This study is classified as acceptable, although it does not fully satisfy all the requirements for the current Test Guideline OECD 474 for in vivo cytogenetic mutagenicity data. Thi
s study is considering as key study for this endpoint.