Registration Dossier

Toxicological information

Developmental toxicity / teratogenicity

Currently viewing:

Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
17-07-2001 to 08-08-2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.31 (Prenatal Developmental Toxicity Study)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)
Deviations:
no
Qualifier:
according to
Guideline:
other: Requirements for Safety Evaluation of Agricultural Chemicals, 59 NohSan No. 4200, Japanese Ministry of Agriculture, Forestry and Fisheries
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
- Age at start of study: approximately 8-10 wk
- Supplier: Fa. Harlan Winkelmann GmbH, Gartenstr. 27, 33178 Borchen
- Housing: Macrolon type III cage, individually on softwood granulate
- Temperature: 20-25°C
- Relative humidity: 30-70%
- Photoperiod: 12 h light/dark cycle
- Acclimatisation before study: atleast 5 d
- Feed: pelleted Ssniff R/Z (V1324), ad libitum
- Water: tap water in plastic bottles, ad libitum

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
- Dose volume: 5 mL/kg
Analytical verification of doses or concentrations:
no
Details on mating procedure:
Virgin female animals in the pre-oestrus or oestrus phase were mated overnight with sexually mature males in the ratio 1 male : 1 female and were caged individually after the detection of sperm in vaginal smears. The day of sperm detection was defined as Day 0 of gestation. Pregnancy was confirmed at necropsy by the detection of implantation sites or normally developed corpora lutea.
Duration of treatment / exposure:
Day 6 to Day 19 of gestation
Frequency of treatment:
once daily
Doses / concentrationsopen allclose all
Dose / conc.:
62.5 mg/kg bw/day (nominal)
Dose / conc.:
250 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
23
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: based on the results of a preliminary range-finding study at dose level of 1000 mg/kg/day, the doses for the study was selected.
- Rationale for animal assignment (if not random): randomization based on a computer-generated algorithm (archived with raw data)
- Observations: during the study period, the treated animals were observed for body weight, food consumption, mortality, cinical signs and examinations related to the uetrine contents.

Examinations

Maternal examinations:
The animals were sacrificed on Day 20 of pregnancy and the fetuses removed by Caesarean section. All animals were examined externally and internally (thoracic and abdominal contents) for macroscopically visible changes, with emphasis on the uterus. Gravid uterus weight was recorded.
Ovaries and uterine content:
The live and dead fetuses in the uterus as well as the conceptuses undergoing resorption and corpora lutea were counted, identified in numerical sequence from cervix to ovary and examined macroscopically. The implantation sites in the uterus were counted after staining with ammonium sulphide.
Fetal examinations:
Approximately 50% of the fetuses of each litter and the dead fetuses were fixed in alcohol, necropsied, sexed and checked for anomalies of the internal organs. After staining with alizarin red S and Alcian blue, the skeletons were examined and checked for stage of development and abnormalities. Visceral and skeletal changes were subdivided into four categories (major defects, minor defects, variations and retardations) based on the severity and/or the spontaneous incidence of the finding.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
Slightly lower mean body weight in the highest dose of 1000 mg/kg/day was marked as statistically significant on Day 20. However, body weight gains were regular during the entire study in the high dose group. This was hence considered an incidental finding.
Food consumption and compound intake (if feeding study):
effects observed, non-treatment-related
Description (incidence and severity):
Transient reduction in absolute food consumption in the highest dose during Days 6 to 9 on on Days 3 to 6 prior to treatment.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Number of abortions:
no effects observed
Pre- and post-implantation loss:
no effects observed
Total litter losses by resorption:
no effects observed
Early or late resorptions:
no effects observed
Dead fetuses:
no effects observed
Changes in pregnancy duration:
no effects observed
Changes in number of pregnant:
no effects observed
Other effects:
no effects observed

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOEL
Effect level:
250 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
body weight and weight gain
food consumption and compound intake
Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Basis for effect level:
other: A minimally lower final body weight and a minimally (not statistically significant) lower number of live fetuses were considered incidental findings and not related to test compound toxicity.

Maternal abnormalities

Abnormalities:
no effects observed

Results (fetuses)

Fetal body weight changes:
no effects observed
Reduction in number of live offspring:
effects observed, non-treatment-related
Description (incidence and severity):
Minimal reductions in the number of live fetuses (not statistically significant) were observed in the high dose. These findings were within the biological variation of this strain.
Changes in sex ratio:
no effects observed
Changes in litter size and weights:
no effects observed
Changes in postnatal survival:
no effects observed
External malformations:
no effects observed
Skeletal malformations:
no effects observed
Visceral malformations:
no effects observed
Other effects:
effects observed, non-treatment-related
Description (incidence and severity):
A minimally higher post-implantation loss (not statistically significant) was observed in the high dose. This finding was within the biological variation of this strain.

Effect levels (fetuses)

open allclose all
Dose descriptor:
NOEL
Effect level:
250 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
reduction in number of live offspring
other: slight increase in post-implantation loss in high dose
Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Sex:
male/female
Basis for effect level:
other: A minimally higher post-implantation loss and a minimally lower number of live fetuses (both not statistically significant) seen in the high dose group were considered incidental findings and not related to test compound toxicity.

Fetal abnormalities

Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
Under the study conditions, the no observed effect level (NOEL) of the test substance in Sprague-Dawley rats is 250 mg/kg bw/day for maternal toxicity and embryotoxicity. A minimally lower final body weight in high-dose dams and a minimally higher post-implantation loss and lower number of live fetuses (both not statistically significant) seen in the high dose group were considered incidental findings and not related to test compound toxicity. These findings might however be related to dental fluorosis as seen in the one generation study due to relatively high fluoride content in the test substance. This effect is only relevant for rats however and does not pose a hazard for humans.
The test substance was not teratogenic in the rats (Ehling, 2002).
Executive summary:

A study was conducted to determine the effects of the test substance on embryonic and fetal development in mated Sprague-Dawley rats according to OECD Guideline 414, EU method B.31, OPPTS Guideline 870.3700 and Japanese Ministry Guideline 59 NohSan No. 4200, in compliance with GLP. The test substance was administered orally by gavage once daily to mated female Sprague Dawley rats from Day 6 - 19 of pregnancy at 0, 62.5, 250 or 1000 mg/kg bw/day and the treated rats were sacrificed on Day 20 of pregnancy. Animals were observed daily for mortality and clinical signs of toxicity. Body weight and food consumption were determined regularly throughout the study. At necropsy the dams were examined for macroscopically visible changes. The uterus was opened and the number of live and dead fetuses and the number of conceptuses undergoing resorption were determined. Body weights, crown-rump lengths, sex ratios of the fetuses and placental weights were determined and external, visceral and skeletal examinations of the fetuses performed. Neither any mortality nor substance-related clinical signs of toxicity occurred throughout the study. Body weight gain of all pregnant females was slightly lower in the high dose group (1000 mg/kg bw/day) during the treatment period. This led to a statistically significant (p<0.05) lower body weight at the end of treatment only. This is considered an incidental finding, as body weight gains were within normal ranges and the curve of body weight development is similar to that of the control group. Statistical evaluation showed an initial reduction (p<0.05) of feed consumption in this group (Days 3 -6) with subsequent recovery thereafter, which is considered to be an incidental occurrence. No substance-related adverse effects were observed at necropsy. There was a slight increase in the number of early or late conceptuses undergoing resorption (post-implantation loss), as well as a slight and not statistically significant decrease in the number of live fetuses at birth in the high dose dams. However, these numbers were within the normal ranges for this strain and, taking into consideration the normal intrauterine development of the conceptuses, considered to be of no toxicological significance. No such findings were observed for mid or low dose group females. Fetal crown-rump lengths, litter size, sex ratios, fetal body weight and placental weights remained unaffected by the administration of the test substance in any group. External, visceral and skeletal examinations of the fetuses did not reveal any substance-related alterations in any group. Under the study conditions, the NOEL of the test substance in Sprague-Dawley rats is 250 mg/kg bw/day for maternal toxicity and embryotoxicity. A minimally lower final body weight in high dose dams and a minimally higher post-implantation loss and lower number of live fetuses (both not statistically significant) seen in the high dose were considered incidental findings and not related to treatment-related. Hence the no observed adverse effect level (NOAEL) of the test substance was considered to be 1000 mg/kg bw/day. The test substance was not teratogenic in the rat (Ehling, 2002).