Phenethyl acetate

Genetic toxicity: in vivo

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:

supporting study

Study period:

1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Not following a guideline, no evidence of GLP. This study was conducted with the aim of evaluating the effectiveness of the protocol

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Benzyl acetate was tested in a mouse bone marrow micronucleus test that employed three daily exposures by intraperitoneal injection. Bone marrow samples were obtained 24 hr following the final exposure. This study was conducted as part of an effort to assess the ability of the micronucleus test to discriminate between rodent carcinogens and noncarcinogens and to determine its potential role, in combination with other short term tests, in identifying genotoxic chemicals that present a carcinogenic hazard.

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: National Toxicology Program production facility
- Age at study initiation: between 9 and 14 weeks
- Weight at study initiation: 25 - 33 g

Note: reference within report to further data on animal husbandry to be found in Tice et al 1991a

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: corn oil
- Justification for choice of solvent/vehicle: water insoluble substance
- Concentration of test material in vehicle: 0, 312, 625, 1250 mg/kg
- Amount of vehicle (if gavage or dermal): 0.4 ml

Details on exposure:

Benzyl acetate was prepared in corn oil and suspended using Tek-Mar Tissumizer. The test substance was administered within 30 minutes of preparation.

Duration of treatment / exposure:

Dose determination study: IP injection on three consecutive days
MN Induction: IP injection on three consecutive days

Frequency of treatment:

Dose determination study: Daily
MN Induction: Daily

Post exposure period:

Dose determination study: 48 hours after the third treatment
MN Induction: 24 hours after the third treatment

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
312 mg/kg bw/day
Basis:
other: Injected intraperitoneal

Doses / concentrations 2

Remarks:

Doses / Concentrations:
625 mg/kg bw/day
Basis:
other: Injected intraperitoneal

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1250 mg/kg bw/day
Basis:
other: Injected intraperitoneal

No. of animals per sex per dose:

Dose determination study: 5 mice

Control animals:

yes, concurrent vehicle

Positive control(s):

7,12-dimethylbenzanthracene
- Route of administration: intraperitoneal injection
- Doses / concentrations: weakly active dose

Examinations

Tissues and cell types examined:

Dose determination study: Bone marrow and peripheral blood smears (two slides/tissue/mouse)

Details of tissue and slide preparation:

Dose determination study:
CRITERIA FOR DOSE SELECTION: The selection of the maximum dose to be tested was based on either mortality, administration characteristics, depression in percentage of bone marrow, or arbitrary maximum dose of 2000 mg/kg/day.

TREATMENT AND SAMPLING TIMES: Groups of 5 mice were administered the test chemical by intraperitoneal injection on three consecutive days. Animals were monitored twice daily and 48 hours after the third treatement the survivng mice were euthanized by CO2 asphyxiation. Bone marrow and peripheral blood smears (two slides/tissue/mouse) by a direct technique.

DETAILS OF SLIDE PREPARATION: Air-dried smears were fixed using absolute methanol and stained with acridine orange.

METHOD OF ANALYSIS:Bone marrow smears from each animal were evaluated at 1000x magnification using epi-illuminated Fluorescence microscopy (450-490 nm excitation, 520 nJ;ll emission) for determination of the percentage of PCE among 200 erythrocytes.

MN Induction:
CRITERIA FOR DOSE SELECTION: Based on the dose selection study.

TREATMENT AND SAMPLING TIMES: Groups of 5-7 mice were administered the test chemical by intraperitoneal inhection on three consecutive days. 24 hours after the third treatement mice were euthanized by CO2 asphyxiation. Bone marrow and peripheral blood smears (two slides/tissue/mouse) were prepared.

DETAILS OF SLIDE PREPARATION: Bone marrow smears (two slides mouse) were prepared, fixed in absolute methanol, and stained with acridine orange.

METHOD OF ANALYSIS:For each animal, slides were evaluated at I,000 X magnification for the number of MN-PCE among 2,000 PCE and for the percentage of PCE among 200 erythrocytes.

Evaluation criteria:

The test conclusions are based on the statistical analysis of trend and of pairwise comparisons of the solvent control with individual doses and the absolute increases in MN-PCE frequency.

Statistics:

The data were analyzed using the Micronucleus Assay Data Management and Statistical software package (version 1.4), which was designed specifically for in vivo micronucleus data. The level of significance was set at an alpha level of 0.05. To determine whether a specific treatment resulted in a significant increase in MN-PCE, the number of MN-PCE were pooled within each dose group and analyzed by a one-tailed trend test. In the software package used, the trend test incorporates a variance innation factor to account for excess animal variability. In the event that the increase in the dose response curve is nonmonotonic, the software program allows for the data to be analyzed for a significant positive trend after data at the highest dose only has been excluded. However, in this event, the alpha level is adjusted to 0.01 to protect against false positives. The %PCE data were analyzed by an analysis of variance (ANOVA) test based on pooled data. Pairwise comparisons between each group and the concurrent solvent control group was by an unadjusted one-tailed Pearson chisquared test which incorporated the calculated variance innation factor for the study.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

No further data

Any other information on results incl. tables

Dose (mg/kg)	MN-PEC/1000 (no of animals)	Pairwise	Survival	%PCE
0	3.00+0.69		5/5	69.9
312	2.90+0.60	0.5519	5/5	65.8
625	3.20+0.60	0.3396	5/5	64.3
1250	1.80+0.46	0.9586	6/6	60.7

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
The initial test was negative to 1,250 mg/kg and was not repeated. According to Directive 67/548/EEC, no classification is warranted. According to Regulation (EC) No. 1272/2008, no classification is warranted.

Executive summary:

Benzyl acetate was tested in a mouse bone marrow micronucleus test that employed three daily exposures by intraperitoneal injection. Bone marrow samples were obtained 24 hr following the final exposure. This study was conducted as part of an effort to assess the ability of the micronucleus test to discriminate between rodent carcinogens and noncarcinogens and to determine its potential role, in combination with other short term tests, in identifying genotoxic chemicals that present a carcinogenic hazard. The initial test was negative to 1,250 mg/kg and was not repeated. According to Directive 67/548/EEC, no classification is warranted. According to Regulation (EC) No. 1272/2008, no classification is warranted.