2-hydroxymethyl-9-methyl-6-(1-methylethyl)-1,4-dioxaspiro[4.5]decane

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented Restriction: no full macroscopic examination; no data on statistical evaluation

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1973

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: unspecified

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

L-menthol

EC Number:

218-690-9

EC Name:

L-menthol

Cas Number:

2216-51-5

IUPAC Name:

2-isopropyl-5-methylcyclohexanol

Details on test material:

Name : Menthol natural brazilian, FDA 71-57

Test animals

Species:

rat

Strain:

Wistar

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

VEHICLE
- Amount of vehicle (if gavage): 10 ml/kg bw

Details on mating procedure:

Virgin adult were mated with young adult males (observation of the vaginal sperm plug was considered Day 0 of gestation)

Duration of treatment / exposure:

gestation days 6-15

Frequency of treatment:

daily

Duration of test:

10 consecutive days

No. of animals per sex per dose:

25 females per dose
No of pregnant animals (2.18, 10.15, 47.05, 218 mg/kg bw): 22, 23, 23, 22

Control animals:

yes, sham-exposed

other: NEGATIVE CONTROL: 25 pregnant... (see attached file)

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS:No data

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: day 0, 6, 11, 15, 20

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #20
- Organs examined: urogenital tract

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes / No / No data
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: No data
- Number of implantations: Yes
- Number of resorptions: Yes

Fetal examinations:

- External examinations: Yes: 1/3 per litter
- Soft tissue examinations: Yes: 1/3 per litter
- Skeletal examinations: Yes: 2/3 per litter
- Head examinations: No data

Other :
- Fetus weight : Yes: all per litter
- Abnormalities/malfunctions : Yes: all per litter

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
No clinical signs of maternal toxicity

Effect levels (maternal animals)

1

Dose descriptor:

NOEL

Effect level:

218 mg/kg bw/day

Based on:

other: L-Menthol

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOEL

Effect level:

318 mg/kg bw/day

Based on:

other: Menthon glycerin-1,2-ketal

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
No clinical signs of fetotoxicity

Effect levels (fetuses)

1

Dose descriptor:

NOEL

Effect level:

218 mg/kg bw/day

Based on:

other: L-Menthol

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOEL

Effect level:

218 mg/kg bw/day

Based on:

other: L-Menthol

Basis for effect level:

other: fetotoxicity

3

Dose descriptor:

NOEL

Effect level:

318 mg/kg bw/day

Based on:

other: Menthon glycerin-1,2-ketal

Basis for effect level:

other: teratogenicity

4

Dose descriptor:

NOEL

Effect level:

318 mg/kg bw/day

Based on:

other: Menthon glycerin-1,2-ketal

Basis for effect level:

other: fetotoxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Maternal toxicity:

- Survival of dams: no deaths

- Body weight of dams: no compound-related changes compared to control (only positive control treated mice showed decreased body weight gain)

Fetotoxicity :

- Death : no dead fetuses in dosage groups (3 deaths in positive control)

- Average fetus weight: no change in treated groups compared to controls

- Abnormalities/malfunctions (no. of fetuses affected/no. of litters affected) (sham control, pos. control, 1.85, 8.59, 39.9, 185.5 mg/kg bw)

- Skeletal findings:

sternebrae (incomplete oss.): 80/22, 94/18, 92/20, 93/22, 101/19, 92/19

sternebrae (missing): 14/6, 11/19, 11/8, 17/5, 11/4, 0/22

skull (incomplete closure): 41/16, 114/19, 46/15, 63/16, 67/20, 49/17

- Soft tissue abnormalities:

pos. control: 7 pups with meningoencephalocele and spina bifida

10.15 mg/kg: 1 pup: petechiae, 1 pup: anophthalmia

47.05 mg/kg: 2 pups anophthalmia, 2 pups: gastroschisis,1 pup hydrocephalus

All other findings were completely in the range of spontaneous abnormalities found in negative controls.

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):

- Organ weights P and F1: no

- Histopathology P and F1:

P: urogenital tract, number of implantation and resorption sites

F1: All fetuses were examined grossly, one-third of fetuses of each litter underwent detailed visceral examinations employing 10x magnification, two-third were examined for skeletal defects

Applicant's summary and conclusion

Conclusions:

L-Menthol was not embryo- or fetotoxic and had no teratogenic properties in well performed gavage studies in rat at non-maternally toxic doses (218 mg/kg bw).

Executive summary:

Teratologic evaluation of FDA 71-57 (menthol natural, Brazilian) was performed according to unspecified guideline. Twenty five female Wistar rats per group were assigned to five dosage groups. Virgin adult females were mated with young adult males. Observation of the vaginal sperm plug was considered Day 0 of gestation. Suspensions of the test substance or the vehicle, corn oil, were administered orally via gavage to 0, 2.18, 10.15, 47.05 and 218.0 mg/kg bw/day at a volume of 10 mL/kg on days 6 through 15 of gestation. Detailed clinical observations were performed daily. Body weight was examined on days 0, 6, 11, 15 and 20. The animals were scarified on gestation day 20 and urogenital tract, number of implantations and resorptions were examined. Foetus was weighted per litter. In addition external, soft tissue and skeletal examinations were performed. There was no cleary discernible effect on nidation or on maternal or fetal survival. The number of abnormalities seen in either soft or skeletal tissues of the test groups did not differ from the number occuring spontaneously in the sham-treated controls. Therefore the NOEL for maternal toxicity and teratogenicity/fetotoxicity is considered to be at 218 mg/kg bw/day of L-Menthol, i.e. the highest applied dose. The NOEL for maternal toxicity and teratogenicity/fetotoxicity extrapolated to menthon glycerin-1,2 -ketal is 318 mg/kg bw/day.