2-methylcyclohexyl acetate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1973

Report date:

1973

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

(corporea lutea not reported, no full dam macroscopic examination)

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Menthol

EC Number:

201-939-0

EC Name:

Menthol

Cas Number:

89-78-1

IUPAC Name:

2-isopropyl-5-methylcyclohexanol

Details on test material:

- Name of test material (as cited in study report): FDA 71-57 (Menthol Natural Brazilian)
- Molecular formula (if other than submission substance): C10H20O
- Molecular weight (if other than submission substance): 156.26

Test animals

Species:

mouse

Strain:

CD-1

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: adult
- Weight at study initiation: 27.0-29.8 g (pregnant dams)
- Housing: Mice were gang-housed in plastic disposable cages in a temperature- and humidity-controlled room.
- Diet: ad libitum
- Water: ad libitum (tap water)

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Administration as a corn oil solution: 10 mL per kg of body weight.

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- Impregnation procedure: Virgin adult females (1 per cage) were mated with untreated young adult males.
- Proof of pregnancy: vaginal sperm plugs, referred to as day 0 of pregnancy

Duration of treatment / exposure:

10 days: beginning on Day 6 and continuing through day 15 of gestation.

Frequency of treatment:

Daily.

Duration of test:

17 days.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

1.85 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

8.59 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

39.9 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

185 mg/kg bw/day (nominal)

No. of animals per sex per dose:

22-23 pregnant females per group.

Control animals:

yes, concurrent vehicle

other: Positive control: 150 mg/kg bw/day of aspirin

Examinations

Maternal examinations:

CLINICAL OBSERVATIONS: Yes
- Time schedule: females were observed daily for appearance and behaviour.

BODY WEIGHT: Yes
- Time schedule for examinations: recorded on days 0, 6, 11, 15 and 17 of gestation.

FOOD CONSUMPTION: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 17 (caesarean section under surgical anesthesia)
- Organs examined: urogenital tract of each dam was examined for anatomical abnormalities.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: No data
- Number of implantations: Yes
- Number of resorptions: Yes (% of live and % partial live resorptions)
- Others: live and dead fetuses; body weight of the live pups.

Fetal examinations:

- External examinations: Yes: mortality, litter size and weights, sex of pups and gross abnormalities to pups.
- Soft tissue examinations: Yes: 1/3 per litter, detailed visceral examination at 10x magnification.
- Skeletal examinations: Yes: 2/3 per litter, cleared in potassium hydroxide (KOH), stained with alizarin red S dye and examined for skeletal defects (sternebrae, ribs, vertebrae, skull, extremities, miscellaneous.

Indices:

Number of implantation sites, number of resorptions, % of live and % partial live resorptions, live fetuses, dead fetuses, and body weight of live pups. Gestation index, mortality, litter size and weights, sex and sex ratio of pups, and gross abnormalities to pups.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Daily clinical observation and measurement of body weight gain failed to show any differences between control and test groups of female mice. The number pregnant and % pregnancy were similar for all dose and control groups. No abortions were observed in any group. The number of live litters, average implant sites per dam were similar for both test and control groups. The % partial resorptions and % complete resorption were increased for the 1.85 and 8.59 mg/kg bw groups, but higher dose levels exhibited lower resorption rates compared to the control groups.

Effect levels (maternal animals)

1

Key result

Dose descriptor:

NOAEL

Effect level:

185 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Key result

Dose descriptor:

NOAEL

Effect level:

185 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

The average fetal weight of treatment and control groups were not statistically different (p>0.05). The total number of live fetuses was similar for test and control groups. Also, there was no significant difference in the number of dead fetuses between test and control groups. Skeletal examination of sternebrae showed no significant differences in the incidence of incomplete ossification or missing sternebrae for test and negative control groups. There was evidence of incomplete ossification in the positive control group. Likewise the incidences of fetuses with more than 13 ribs, incomplete ossification of vertebrae and extremities, incomplete skull closure were similar for test and negative control animals. Visceral examination failed to reveal any evidence of soft tissue abnormalities at any dose level.

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

There was no evidence of maternal toxicity or developmental toxicity at dose levels up to and including 185 mg/kg bw/day of test material.

Applicant's summary and conclusion

Conclusions:

The maternal and developmental NOAEL for 2-Isopropyl-5-methylcyclohexanol in mice was determined to be 185 mg/kg bw/day.

Executive summary:

The developmental toxicity of 2-Isopropyl-5-methylcyclohexanol was investigated in CD-1 mice. Virgin adult female CD-1 outbred mice were mated with untreated young adult males and observation of vaginal sperm plugs was considered day 0 of gestation. Beginning on Day 6 and continuing daily through Day 15 of gestation, groups (22-23/group) of pregnant females were given 0, 1.85, 8.59, 39.9, 185 mg/kg bw of the test material (FDA 7157) by gavage in corn oil. A positive control group received 150 mg/kg bw/day of aspirin. Body weights were recorded on days 0, 6, 11, 15, and 17 of gestation. On Day 17 all dams were subjected to Caesarian section. Referring to the maternal observations daily clinical observation and measurement of body weight gain failed to show any differences between control and test groups of female mice. The number pregnant and % pregnancy were similar for all dose and control groups. No abortions were observed in any group. The number of live litters, average implant sites per dam were similar for both test and control groups. The % partial resorptions and % complete resorption were increased for the 1.85 and 8.59 mg/kg bw groups, but higher dose levels exhibited lower resorption rates compared to the control groups. Referring to the fetal data, the average fetal weight of treatment and control groups were not statistically different (p>0.05). The total number of live fetuses was similar for test and control groups. Also, there was no significant difference in the number of dead fetuses between test and control groups. Skeletal examination of sternebrae showed no significant differences in the incidence of incomplete ossification or missing sternebrae for test and negative control groups. There was evidence of incomplete ossification in the positive control group. Likewise the incidences of fetuses with more than 13 ribs, incomplete ossification of vertebrae and extremities, incomplete skull closure were similar for test and negative control animals. Visceral examination failed to reveal any evidence of soft tissue abnormalities at any dose level. There was no evidence of maternal toxicity or developmental toxicity at dose levels up to and including 185 mg/kg bw/day of test material. The maternal and developmental NOAEL for 2-Isopropyl-5-methylcyclohexanol in mice was determined to be 185 mg/kg bw/day.