Dioctadecyl ether

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:

1st mating results: April 28, 2009; 1st administration: May 04, 2009; Termination of in-life phase: June 01, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD 414)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Guideline:

EU Method B.31 (Prenatal Developmental Toxicity Study)

Test guideline 2

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dioctyl ether

EC Number:

211-112-6

EC Name:

Dioctyl ether

Cas Number:

629-82-3

IUPAC Name:

1,1'-oxydioctane

Details on test material:

- Name of test material (as cited in study report): C-SAT 080029
- Molecular formula (if other than submission substance):
- Molecular weight (if other than submission substance):
- Smiles notation (if other than submission substance):
- InChl (if other than submission substance):
- Structural formula attached as image file (if other than submission substance):
- Substance type:
- Physical state: colourless liquid
- Analytical purity:
- Impurities (identity and concentrations):
- Composition of test material, percentage of components: dioctylether: 99.1%
- Isomers composition:
- Purity test date: February 27, 2008
- Lot/batch No.: CE72530027
- Expiration date of the lot/batch: September 09, 2009
- Radiochemical purity (if radiolabelling):
- Specific activity (if radiolabelling):
- Locations of the label (if radiolabelling):
- Expiration date of radiochemical substance (if radiolabelling):
- Stability under test conditions: September 09, 2009
- Storage condition of test material: at room temperature
- Other:

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Germany GmbH, 97633 Sulzfeld, Germany
- Age at study initiation: 8 - 9 weeks (on day 0 of pregnancy)
- Weight at study initiation: 190 - 266 g (on day 0 of pregnancy)
- Fasting period before study: no
- Housing: singly
- Diet (e.g. ad libitum): conventional laboratory diet ad libitum
- Water (e.g. ad libitum): drinking water ad libitum
- Acclimation period: 6 adaptation days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3 (maximum range)
- Humidity (%): 55 +/- 15 (maximum range)
- Air changes (per hr): 12 -18 times
- Photoperiod (hrs dark / hrs light): 12 hrs dark / 12 hrs light


IN-LIFE DATES: From: April 28, 2009 To: June 01, 2009

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: sunflower oil

Details on exposure:

The test item was suspended in the vehicle (sunflower oil) to the appropriate concentrations and was administered orally at a constant volume of 5 mL/kg b.w. once daily from the 6th to the 19th day of pregnancy. The test item-vehicle mixtures were freshly prepared every day.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The determination of the concentration of C-SAT 080029 in the vehicle sunflower oil was performed using a gas chromatography (GC) method with FID detection. The concentration of C-SAT 080029 in the mixture was quantified using a calibration curve calculated from defined peak areas of the test item. The analytical method used was developed and validated by LPT for linearity of the calibration curve, accuracy, precision, stability, specificity and sensitivity. The measured concentrations ranged from 107.3% to 108.4%. The results were well within the admissible limits of 90% to 110% of the normal concentration.

Details on mating procedure:

Sexually mature male rats of the same breed served as partners. The male and female breeding partners were randomly chosen. Mating was monogamous: 1 male and 1 female animal were placed together in one cage during the dark period. Each morning a vaginal smear was taken to check for the presence of sperm and the stage of oestrus cycle. If findings were negative, mating was repeated with the same partner. The day on which sperm was found was considered as the day of conception (day 0 of pregnancy). This procedure was repeated until enough pregnant dams were available for all groups. Rats which did not become pregnant were excluded from analysis of the results and replaced by other animals. A post-mortem negative staining according to SALEWSKI was carried out in the replaced animals in order to confirm the non-pregnancy status.

Duration of treatment / exposure:

from day 6 to 19 of pregnancy

Frequency of treatment:

once daily

Duration of test:

4 months (April 28, 2009 to August 31, 2009)

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 300, 1000 mg/kg b.w./day
Basis:
actual ingested

No. of animals per sex per dose:

25 pregnant rats per dose (to obtain 20 litters per dose)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: in agreement with the Sponsor based on available toxicological data
- Rationale for animal assignment (if not random): The rat is a commonly used rodent species for embryotoxicity studies.
- Other: no

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
Clinical signs
- Time schedule: regularly throughout the working day from 7.00 a.m. to 3.45 p.m., on Saturdays and Sundays, starting from 7.00 a.m. to 11.00 a.m. with a final check at approx. 3.30 p.m.
- Cage side observations checked : behaviour, external appearance and nature of the faeces
Viability: early in each working day and again in the afternoon to look for dead or moribund animals
Body weight: on day 0 of gestation followed by daily weighings - always at the same time of the day. The body weight was also calculated in intervals (i.e. day 0-3, 3-6, 6-9, 9-12, 12-15, 15-18 and 18-20). Furthermore the net weight change from day 6 was given.
Food consumption: recorded daily with the exception of gestation day 20
Drinking water consumption: daily monitoring by visual appraisal of the drinking water bottles

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once daily


BODY WEIGHT: Yes
- Time schedule for examinations: on day 0 of gestation followed by daily weighings - always at the same time of the day. The body weight gain was also calculated in intervals (i.e. day 0-3,3-6, 6-9, 9-12, 12-15, 15-18 and 18-20). Furthermore the net weight change from day 6 was given.


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


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes / No / No data
- Time schedule for examinations: daily monitoring by visual appraisal of the drinking water bottles


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20 of gestation
- Organs examined: internal organs and placentae


OTHER:

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
- Other: location of fetuses in the uterus

Fetal examinations:

- External examinations: Yes: [ all per litter ] : for damages, especially for malformations
- Soft tissue examinations: Yes: [ half per litter ] : for soft tissue anomalies. Body sections were made and examined according to WILSON.
- Skeletal examinations: Yes: [half per litter ]: for skeletal anomalies. The thorax and peritoneal cavity (without damage to ribs and sternum) were opened and the location, size and condition of the internal organs were determined. Then the skeleton was double-stained with Alcian blue for the examination of cartilage and with Alizarin red to reveal ossifications (according to DAWSON). The skeletal system was examined (determination of the number and type of retardations, variations as well as malformations).
- Head examinations: Yes: [ half per litter ] included in soft tissue examination of body sections

Statistics:

For all numerical values, homogeneity of variances was tested using the BARTLETT chi-square test. When the variances were homogeneous, the DUNNETT test (p <= 0.01) was used to compare the experimental groups out, limit of significance was p <= 0.01.
For comparison of classification measurements (for example malformation-, resorption-, retardation- and variation rate) the FISHER's exact test (n < 100) or chi-square test with YATES' correction for continuity (n >= 100) (p <= 0.05 and p <= 0.01) was employed.

Indices:

Corpora lutea: number per dam, absolute number per group, mean per group
Implantations: number per dam, distribution in the uterine horns, absolute number per group, mean per group
Reorptions: number per dam, % per litter; distribution in the uterine horns, absolute number per group, mean per group, mean % per group, early resorptions < 2 mm, number and % per litter; late resorptions > 2 mm, number and % per litter; % litters with resorptions per group
Resorptions rate [%]: resorptions / implantations x 100
Weight of placentae: individual data per fetus, mean per litter, mean per group, litter mean per sex and group
Weight of fetuses: individual data per fetus, mean per litter, mean per sex and litter, litter mean per group, litter mean per sex and group
Fetuses: number and % per dam (alive and dead), number of fetuses per sex and dam, sex ratio per litter, distribution in the uterine horns, absolute number of fetuses alive per group, mean number of fetuses alive per group, mean % of fetuses alive per group, mean % per sex and group
Dead fetuses: number per dam, mean per group
Runts: number per dam, mean per group
Malformed fetuses: individual data per fetus, mean per group and type of malformation
Malformation rate [%]: malformed fetuses / fetuses x 100
Fetuses with variations: individual data per fetus grouped according to litter and dose, number and % offspring with external, visceral or skeletal variations per litter; mean % per group and type of variation
Variation rate [%]: fetuses with variations / fetuses x 100
Fetuses with retardations: individual data per fetus, mean per goup and type of retardation
Retardation rate [%]: fetuses with retardations / fetuses x 100
Pre-implantation loss [%]: corpora lutea - implantations / corpora lutea x 100
Post-implantation loss [%]: implantations - living fetuses /implantations x 100

Historical control data:

Summarized results of 45 last embryotoxicity studies in Sprague-Dawley rats performed at LPT in the years 2000 to June 2009 (1. General reproductive incidences, 2. Skeletal retardations, 3. Variations a) skeletal, b) visceral, 4. Malformations)

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Effect levels (maternal animals)

Dose descriptor:

NOEL

Effect level:

> 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Effect levels (fetuses)

1

Dose descriptor:

NOEL

Effect level:

> 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOEL

Effect level:

> 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: embryotoxicity

3

Dose descriptor:

NOEL

Effect level:

> 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: fetotoxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified