A mixture of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran; cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

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:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducting according to OECD method by a GLP accredited laboratory.

Data source

Reference

Reference Type:

other: Body responsible for the test

Title:

Tetrahydro-4-methyl-2-propyl-2H-pyran-4-yl acetate: Mouse micronucleus test

Year:

1993

Bibliographic source:

Unpublished report

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran; cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

EC Number:

412-450-9

EC Name:

A mixture of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran; cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

Cas Number:

131766-73-9

Molecular formula:

C11H20O3

IUPAC Name:

reaction mass of: trans-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran cis-4-acetoxy-4-methyl-2-propyl-tetrahydro-2H-pyran

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male/female

Details on test animals or test system and environmental conditions:

CD-1 mice (20/sex) weighing 22-24 g on receipt (acclimatized for ~4 days) were group-housed separated by sex (number per cage not stated) and given free access to Biosure LAD 1 rodent diet and drinking water. The animal room temperature was 22°C and a light photoperiod of 12 hours.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

1% methylcellulose

Details on exposure:

The mice were gavaged with 1600 mg test substance/kg body weight. Mice were fasted overnight prior to and for 2 hours after dosing.

Duration of treatment / exposure:

one dose

Frequency of treatment:

single dose

Post exposure period:

24, 48, and 72 hours

Doses / concentrations

Remarks:

Doses / Concentrations:
20 ml/kg body weight
Basis:
actual ingested

No. of animals per sex per dose:

5 mice/sex/dose

Control animals:

yes, concurrent vehicle

Positive control(s):

A positive control group consisting of 5 mice/sex received a single dose of 12 mg/kg bw of Mitomycin C. Positive control animals were killed at 24 hours.

Examinations

Details of tissue and slide preparation:

Both femurs were dissected out from each animal, were cleared of tissue and the proximal epiphysis was removed from each bone. The bone marrow smears were made directly on glass microscope slides containing a drop of calf serum. One slide per femur was prepared. The smears were fixed in methanol, air-dried, stained with 10% Giemsa, rinsed with distilled water, air-dried, and mounted with coverslips using DPX.
The stained smears were examined by light microscopy to determine the incidence of micronucleated cells per 1000 polychromatic erythrocytes per mouse. The proportion of polychromatic to normochromatic erythrocytes was assessed by examination of at least 1000 erythrocytes and the number of micronucleated mature erythrocytes was recorded.

Evaluation criteria:

A response was considered positive if there was a substantial statistically significant increase in the incidence of micronucleated immature erythrocytes compared to that of vehicle controls. Bone marrow toxicity is identified by a substantial, statistically significant decrease in the proportion of polychromatic to normochromatic erythrocytes.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

see additional information on results

Vehicle controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

No statistically significant change in number of micronucleated polychromatic erythrocytes or micronucleated normochromatic erythrocytes at any of the 3 sampling times; a small, but statistically significant, decrease in the ratio of polychromatic to normochromatic erythrocytes compared to vehicle control (0.754 versus 1.157) seen at 72-hour sampling time but not at other 2 sampling times (1.077 at 24 hours; 0.945 at 48 hours)

Any other information on results incl. tables

The positive control caused a highly significant increase in the frequency of micronucleated polychromatic erythrocytes and did not cause any statistically significant decreases in the ratio of polychromatic to normochromatic erythrocytes.

2 male and 5 females died after dosing due to gavage error (confirmed at necropsy). These animals were replaced by the 5 additional mice per sex dosed at the same time. Clinical signs included hunched posture, increased respiratory rate, lethargy, loss of righting reflex, pilo-erection, staggering gait, and tail black at tip.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Under the conditions of this study, the test substance did not show any evidence of causing chromosome damage when administered orally in this in vivo test procedure.

Executive summary:

The mammalian Erythrocyte Micronucleus Test according to OECD method 474 has been employed to assess the potential of the test substance to induce mutagenic effects in mice following acute oral administration. 5 groups of mice per sex per dose CD-1 mice were gavaged with 1600 mg test substance/kg, a positive control or the vehicle body weight in 1% methylcellulose at a dose volume of 20 ml/kg body weight. After sacrifice after 24, 48, and 72 hours post-dosing, the proportion of polychromatic to normochromatic erythrocytes was assessed. The test substance did not show any evidence of causing chromosome damage when administered orally in this in vivo test procedure.