A mixture of: cis-tetrahydro-2-isobutyl-4-methylpyran-4-ol; trans-tetrahydro-2-isobutyl-4-methylpyran-4-ol

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes (incl. QA statement)

Remarks:

BASF SE

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

A mixture of: cis-tetrahydro-2-isobutyl-4-methylpyran-4-ol; trans-tetrahydro-2-isobutyl-4-methylpyran-4-ol

EC Number:

405-040-6

EC Name:

A mixture of: cis-tetrahydro-2-isobutyl-4-methylpyran-4-ol; trans-tetrahydro-2-isobutyl-4-methylpyran-4-ol

Cas Number:

63500-71-0

Molecular formula:

C10 H20 O2

IUPAC Name:

4-methyl-2-(2-methylpropyl)oxan-4-ol

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Pyranol
- Physical state: liquid/colorless, clear
- Analytical purity: 99.6 corr. area-% as a mixture out of two diasteromers
- Lot/batch No.: 00027577L0
- Test substance No.: 09/0639-4
- Homogeneity: given (visually)
- Stability under test conditions: expire date 29 Oct 2015

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Strain: Time-mated Wistar rats (CrIGIxBrIHan:WI)
- Source: Charles River Laboratories, Research Models and services, Germany
- Animal identification: by ear tattoo
- Housing: singly from day 0 - 20 p .c. in type DK III stainless steel wire mesh cages supplied by BECKER & CO., Castrop-Rauxel, FRG (height : 15 cm, length: 37,5 cm, width: 21 cm; floor area about 800 cm2)
- Diet (e.g. ad libitum): ad libitum, ground Kliba maintenance diet rat/mouse/hamster meal (PROVIMI KLIBA SA, Kaiseraugst, Switzerland)
- Water (e.g. ad libitum): ad libitum, drinking water of tap water quality from water bottles
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12 / 12

ANALYSES
- Food: assayed for chemical as well as for microbiological contaminants
- Water: regularly assayed for chemical contaminants by the municipal authorities of Frankenthal and by Technical Services of BASF Aktiengesellschaft as well as for the presence of microorganisms by a contract laboratory

Administration / exposure

Route of administration:

dermal

Vehicle:

olive oil

Analytical verification of doses or concentrations:

yes

Details on mating procedure:

- Impregnation procedure: purchased timed pregnant:
The animals were mated by the breeder ("time-mated") and supplied on day 0 post coitum (= detection of vaginal plug / sperm). The animals arrived  on the same day (i.e. day 0 p.c.) at the experimental laboratory. The  following day was designed "day 1" post coitum (p.c.). Animals were assigned to the test groups by taken random selection.

Duration of treatment / exposure:

day 6 through day 19 post coitum (p.c.)

Frequency of treatment:

once daily for at least 6 hours

Duration of test:

On day 20 p.c. all surviving females were sacrificed

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300, 1000 mg/kg bw/d
Basis:
nominal conc.

No. of animals per sex per dose:

25

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes, check for mortality
- Time schedule: twice a day on working days or once a day (Saturday, Sunday or on public holidays) (days 0-20 p.c.)

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once a day, or more often when clinical signs of toxicity were elicited (days 0-20 p.c.)

BODY WEIGHT: Yes
- Time schedule for examinations: on days 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20 p.c.
The body weight change of the animals was calculated from these results

CORRECTED BODY WEIGHT GAIN (net maternal body weight change): Yes
- Time schedule: calculated after terminal sacrifice (terminal body weight on day 20 p.c. minus weight of the  unopened uterus minus body weight on day 6 p.c.)

FOOD CONSUMPTION: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: liver, uterus, ovaries

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Number of dead fetuses: Yes
- Calculations of conception rate and pre- and postimplantation losses

Fetal examinations:

Each fetus was weighed and examined macroscopically for any external findings. Furthermore, the viability of the fetuses and the condition of the placentae, the umbilical cords, the fetal membranes, and fluids were examined. Individual placental weights were recorded.
- External examinations: Yes
- Soft tissue examinations: Yes
- Skeletal examinations: Yes
- Head examinations: Yes

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
Clinical examinations of the dams:
Only pregnant dams were used for the study. Therefore, the following females were excluded:
- Test group 0 (0 mg/kg bw/d): one female – not pregnant
- Test group 3 (1000 mg/kg bw/d): one female – not pregnant

Mortality:
There were no substance-related or spontaneous mortalities in any females of all test groups.

Clinical symptoms:
No clinical signs or changes of general behavior, which may be attributed to the test sub-stance, were detected in any female at dose levels of 100, 300 or 1000 mg/kg bw/d during the entire study period.
One low-dose (100 mg/kg bw/d), three mid-dose (300 mg/kg bw/d) as well as one high-dose animal (1000 mg/kg bw/d) occasionally showed vaginal hemorrhage either before daily dermal application or after the daily 6-hour exposure time. This finding was observed in these individuals on GD 15-17 only, and is most likely related to handling and semiocclusive dressing, but not to the test substance itself. The assessment was also supported by the fact that no impairment of reproduction parameters became obvious.

Skin examination:
The treated skin of all female animals of all test groups 0-3 was free from any notable findings during the entire study period.

Food consumption:
The mean food consumption of the dams in test groups 1-3 was comparable to the concurrent control throughout the entire study period.

Body weight data:
The mean body weights and the average body weight gains of all test substance-treated dams in test groups 1-3 were comparable to the controls throughout the entire study period. However, on GD 6-8, the mean body weight gain value of the high-dose dams (1000 mg/kg bw/d) was significantly lower (-37%), but recovered afterwards and was comparable throughout the remaining treatment period.

Corrected (net) body weight gain:
The corrected body weight gain of animals in test groups 1-3 was not influenced by treatment. The differences between these groups and the control group revealed no dose-dependency and were assessed to be without biological relevance.

Uterus weight:
The mean gravid uterus weights of the animals of test group 1-3 were not influenced by the test substance. The differences between these groups and the control group revealed no dose-dependency and were assessed to be without biological relevance.

Necropsy findings:
No necropsy findings which could be attributed to the test substance were seen in any dam.

Reproduction data:
The conception rate was 96% in test groups 0 and 3 (0 and 1000 mg/kg bw/d) and 100% in test groups 1 and 2 (100 and 300 mg/kg bw/d).
No test substance-related and/or biologically relevant differences between the test groups 0, 1, 2 and 3 were observed with regard to conception rate, mean number of corpora lutea and implantation sites or values calculated for the pre- and the postimplantation losses, the number of resorptions as well as viable fetuses. All observed differences were considered to reflect the normal range of fluctuations for animals of this strain and age. This includes the apparently lower mean number of viable female fetuses in test group 2 (300 mg/kg bw/d).

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Remarks:

maternal toxicity

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: no test substance-related, adverse effects up to limit dose

Maternal abnormalities

Key result

Abnormalities:

no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Sex distribution of the fetuses:
The sex distribution of the fetuses in test groups 1-3 was comparable to the control fetuses. The significantly lower mean number of viable female fetuses in test group 2 (300 mg/kg bw/d) was considered to be incidental and without any toxicological relevance.

Weight of the placentae:
The mean placental weights of test groups 1-3 were comparable to the corresponding control group.

Weight of the fetuses:
The mean fetal weights were comparable between the control and test groups 1-3. Biologically relevant differences were not observed. The significantly lower mean weight of female fetuses in test group 1 (100 mg/kg bw/d) did not show a dose-response relationship and was clearly within the historical control data.

Fetal external malformations:
No external malformations were recorded.

Fetal external variations:
One external variation, i.e. limb hyperextension, was detected for one high-dose fetus (1000 mg/kg bw/d). This single finding was considered to be spontaneous in nature.

Fetal external unclassified observations:
No unclassified external observations were recorded.

Fetal soft tissue malformations:
No soft tissue malformations were recorded.

Fetal soft tissue variations:
Two soft tissue variations were detected, i.e. large liver lobe and dilated renal pelvis. The incidences of these variations were neither significantly nor dose-dependently increased. Therefore, all differences were not considered biologically relevant.

Fetal soft tissue unclassified observations:
No unclassified soft tissue observations were recorded.

Fetal skeletal malformations:
One skeletal malformation was detected in test group 3 (1000 mg/kg bw/d) affecting the fore-limb. This single finding can be found in the historical control data in a comparable frequency. An association to the treatment was not assumed.

Fetal skeletal variations:
For all test groups, skeletal variations of different bone structures were observed, with or without effects on corresponding cartilages. The observed skeletal variations were related to several parts of fetal skeleton and appeared without a relation to dosing. The overall incidences of skeletal variations were comparable to the historical control data.
The increased incidence of the skeletal variation “wavy rib” was only marginally above the historical control data. Therefore, the finding was regarded to be incidental and not related to treatment.

Fetal skeletal unclassified cartilage observations
Some isolated cartilage findings without impact on the respective bony structures, which were designated as unclassified cartilage observations, occurred in all test groups. The observed unclassified cartilage findings were related to the skull, the sternum and ribs. They did not show any relation to treatment.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no test substance-related, adverse effects up to limit dose

Fetal abnormalities

Key result

Abnormalities:

no effects observed

Overall developmental toxicity

Key result

Developmental effects observed:

no