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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: DNA damage and/or repair
Type of information:
experimental study
Adequacy of study:
key study
Study period:
01.09.2004 to 29.11.2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was performed according to the OECD guideline 474 and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report date:
2004

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
(1R,2S,5R)-2-isopropyl-5-methylcyclohexyl (2R,5R)-5-hydroxy-1,3-oxathiolane-2-carboxylate
EC Number:
604-569-1
Cas Number:
147126-62-3
Molecular formula:
C14H24O4S
IUPAC Name:
(1R,2S,5R)-2-isopropyl-5-methylcyclohexyl (2R,5R)-5-hydroxy-1,3-oxathiolane-2-carboxylate
Constituent 2
Reference substance name:
OS Menthol Ester
IUPAC Name:
OS Menthol Ester
Constituent 3
Reference substance name:
(2R, 5R)-5-Hydroxy-[1 ,3]oxathiolane-2-carboxylic acid, 2S-isopropyl-5R-methyl-1R-cyclohexyl ester
IUPAC Name:
(2R, 5R)-5-Hydroxy-[1 ,3]oxathiolane-2-carboxylic acid, 2S-isopropyl-5R-methyl-1R-cyclohexyl ester
Test material form:
solid: compact

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Age at study initiation: 8 weeks at delivery
- Housing: 7 animals/cage, housed in 'shoe box' cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: yes, 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): l9°C to 25°C
- Humidity (%): 30-70
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: XX.YY.ZZZZ To: XX.YY.ZZZZ ???

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Methyl cellulose 1% in water
Details on exposure:
EXPERIMENTAL DESIGN:
Phase I: RANGE FINDING STUDY with three groups of 6 mice per group were given the test article orally at 500.0, 1000.0 and 2000.0 mg!kg
Phase II: main micronucleus test (dosing of test group, vehicle control group and positive control group)

PREPARATION OF DOSING SOLUTIONS:
A stock solution/suspension of the test material was prepared in the vehicle. All test and positive control substance dosing preparations were prepared as
close to the time of dosing as possible. Dosing volume will not normally exceed 1.0 mL per mouse.
Duration of treatment / exposure:
24, 36 and 48 hours
Frequency of treatment:
single oral dose (gavage)
Post exposure period:
none
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
2000 mg/kg bw
Basis:
other: suspended in 1% methyl cellulose in water
Remarks:
Doses / Concentrations:
1000 mg/kg bw
Basis:
other: suspended in 1% methyl cellulose in water
Remarks:
Doses / Concentrations:
500 mg/kg bw
Basis:
other: suspended in 1% methyl cellulose in water
Remarks:
Doses / Concentrations:
70 mg/kg
Basis:
other: cyclophosphamide as positve Control
No. of animals per sex per dose:
Test group: 3 (21 mice/group)
Vehicle control group: 1 (21 mice/group)
Positive control group: 1 (21 mice/group)
(All groups consisted of males only)
Control animals:
yes, concurrent vehicle
Positive control(s):
The positive control group received cyclophosphamide at 70 mg/kg by oral gavage.

Examinations

Tissues and cell types examined:
Bone marrow, immature erythrocytes
Details of tissue and slide preparation:
TISSUE PREPARATION:
Seven animals from each group were sacrificed at 24, 36 and 48 hours after dosing. At each time point, hone marrow was recovered from both femora from allanimals. Bone marrow smears were prepared, fixed and stained (MayGrunwald/Giemsa) for evaluation.

SLIDE PREPARATION:
Slides will be briefly flamed and then :fixed by immersing in 95% ethanol for 10- 15 minutes. This procedure was repeated to give X smears of marrow per slide.
The slides were air dried and fixed in solvent (methanol) for at least 2-3 minutes. The slides were stained with a solution of Jenner's Giemsa Working Solution
for 6-12 minutes, then stained with a solution of May·Gruenwald Giemsa Werking Solution for 45 minutes. Slides will be randomly sampled and inspected for
quality of staining. If staining is deemed acceptable, then the s!ides will be air-dried.

SLIDE ANALYSIS:
2000 polychromatic erythrocytes (PCEs) per animal were scored for presence of micronuclei.
The coded slide for each animal should have 2000 polychromatic erythrocytes secred for the incidence of micronuclei. The ratio of polychromatic to
normochromatic erythrocytes within these 2000 cells is then determined for each animal.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Based on the above results, the test article, OS Menthol Ester, did not induce micronuclei in the Mouse Micronucleus Test at dose levels up to 2000.0mg/kg administered.orally in mice; it was not clastogenic and did not interact with the mitotic spindle.
Executive summary:

Under the conditions of this experiment the substance did not induce formation of micronuclei in male mice at up to 2000 mg/kg bw.

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