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Toxicological information

Developmental toxicity / teratogenicity

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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:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes (incl. certificate)
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: charge 2

Test animals

Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH
- Age at study initiation: age of 10-12 weeks, animals were paired at the breeder and supplied on day 0 p.c.
- Weight at study initiation: 137.1-194.8 g
- Housing: single housing in type DK III stainless steel wire mesh cages
- Diet: Kliba maintenance diet mouse/rat “GLP”, ad libitum
- Water: ad libitum supplied water bottles
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20-24°C
- Humidity: 30-70 %
- Air changes: fully air-coniditioned
- Photoperiod (hrs dark / hrs light): 12 h / 12 h

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Remarks:
tap water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
The test substance solutions were prepared at the beginning of the administration period and thereafter at intervals, which took into account the analytical results of the stability verification. For the preparation of the solutions, an appropriate amount of the test substance was weighed in a graduated measuring flask depending on the dose group, topped up with tap water and subsequently intensely shaken.


Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Analytical verifications of the stability of the test substance in tap water for a period of at least 4 days at room temperature were carried out before the study was initiated, in a similar batch. Samples of the test substance solutions were sent to the analytical laboratory twice during the study period (at the beginning and towards the end) for verification of the concentrations. Since the test substance preparations were solutions, investigations into homogeneity were not conducted.
Details on mating procedure:
- Impregnation procedure: purchased timed pregnant
Duration of treatment / exposure:
day 6 to day 19 p.c.
Frequency of treatment:
daily
Duration of test:
until day 20 p.c.
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (actual dose received)
Dose / conc.:
100 mg/kg bw/day (actual dose received)
Dose / conc.:
300 mg/kg bw/day (actual dose received)
Dose / conc.:
1 000 mg/kg bw/day (actual dose received)
No. of animals per sex per dose:
25
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The following doses were chosen for the present prenatal developmental toxicity study in Wistar rats:
100 mg/kg body weight/day: as the expected no observable adverse effect level
300 mg/kg body weight/day: as intermediate dose level
1000 mg/kg body weight/day: as the dose level which should induce some developmental and/or maternal toxicity but not death or severe suffering
The oral route was selected since this has proven to be suitable for the detection of a toxicological hazard.

Examinations

Maternal examinations:
Clinical examinations
Mortality
A check was made twice a day on working days or once a day on Saturdays, Sundays or on public holidays (days 0-20 p.c.).

Clinical symptoms
A cage-side examination was conducted at least once daily for any signs of morbidity, pertinent behavioral changes and signs of overt toxicity. If such signs occurred, the animals were examined several times daily (days 0-20 p.c.).

Food consumption
With the exception of day 0, the consumption of food was determined on the same days as body weight.

Body weight data
All animals were weighed 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 based on the obtained results.

Corrected (net) body weight gain
Furthermore, the corrected body weight gain was 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.).

Necropsy
On day 20 p.c., the dams were sacrificed after Isoflurane anesthesia by cervical dislocation, in randomized order. After the dams had been sacrificed, they were necropsied and assessed by gross pathology, in randomized order. Uterus and ovaries were removed and examined as described in the "Ovaries and uterine content" section.
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
Fetal examinations:
- External examinations: Yes: [all per litter]
all fetuses were checked for viability, sexed, examined macroscopically and weighed. Furthermore, the condition of placentae, umbilical cords, fetal membranes, and fluids were examined. Individual placental weights were recorded.
- Soft tissue examinations: Yes: [half per litter]
The fetuses fixed in Harrison’s fluid were examined for any visceral findings according to the method of BARROW and TAYLOR
- Skeletal examinations: Yes: [half per litter]
The skeletons of the fetuses fixed in ethyl alcohol were stained according to a modified method of KIMMEL and TRAMMELL. Thereafter, the skeletons of these fetuses were examined under a stereomicroscope


Statistics:
The one-sided Wilcoxon test and Fshers' exact test were applied.
Historical control data:
Historical control data are included in form of an Appendix to the study report.

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 symptoms

1000 mg/kg bw: Taken together, 18 rats of the high-dose group showed transient salivation after treatment from day 9 p.c. onwards and persisted in the respective females for a few minutes directly after treatment. On day 20 p.c., the day after cessation of treatment, salivation was not observed in these rats. The observed temporary salivation of the animals is considered to be treatment-related. Most likely salivation was induced by the bad taste of the test substance or by local irritation of the upper digestive tract. This type of finding is not assessed as an adverse effect of systemic toxicity.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Basis for effect level:
other: maternal toxicity

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects: no effects

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Remarks on result:
not determinable due to absence of adverse toxic effects

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
Under the conditions of this prenatal developmental toxicity study, the oral administration of the test item to pregnant Wistar rats from implantation to one day prior to the expected day of parturition (days 6-19 p.c.) elicited no signs of maternal toxicity. In addition, no test substance-related influences on gestational parameters were observed. There was no evidence of an adverse developmental effect of the test item at dose levels as high as 1000 mg/kg bw/d.