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EC number: 258-436-4
CAS number: 53220-22-7
Please refer to result tables attached.
The test item was examined for its possible
prenatal developmental toxicity in accordance with OECD TG 414 and under
Groups of 25 sperm-positive female Han: of
Wistar origin rats were treated with the test item by oral
administration daily at three dose levels of 100, 300 and 1000 mg/kg
bw/day respectively from day 5 up to and including day 19 post coitum. A
control group of 25 sperm positive females was included and the animals
were given the vehicle PEG 400. The treatment volume was 5 mL/kg bw.
A sufficient stability and homogeneity in
the chosen vehicle were verified over the range of relevant
concentrations at the appropriate frequency of preparation. The test
item in PEG 400 was stable at room temperature for at least one day and
for three days in the refrigerator (5 ± 3 °C) at the concentrations of 1
and 200 mg/mL. Analytical control of dosing solutions was performed
during the first and last week of treatment. Concentrations of the test
item in the dosing formulations varied in the acceptable range between
93 and 98 % of nominal concentrations at both analytical occasions
confirming proper dosing.
During the study, mortality was checked and
clinical observations were performed. Body weight and food consumption
of the dams were also recorded. The day, when sperm was detected in the
vaginal smear, was regarded as day 0 of gestation. Blood sampling for
determination of thyroid hormones FT3 and FT4 as well as TSH, Caesarean
section and gross pathology were performed on gestational day 20.
Thyroids were weighed and evaluated histologically. The number of
implantations, early and late resorptions, live and dead fetuses in each
uterine horn and the number of corpora lutea were recorded. Each fetus
was weighed and examined for sex and gross external abnormalities. The
placentas were weighed and examined externally. About half of each
litter was preserved for visceral examination and the other half of the
litters were preserved for skeletal evaluation. At visceral examination
the bodies were micro dissected by means of a dissecting microscope. The
heads were examined by Wilson's free-hand razor blade method. After
cartilage-bone staining the skeletons were examined by means of a
dissecting microscope. All abnormalities found during the fetal
examinations were recorded.
In total, on gestation day 20 there were 19,
20, 21 and 21 evaluated litters in the control, 100, 300 and 1000 mg/kg
bw/day group respectively. None of the females died before scheduled
necropsy and there were no test item related clinical signs recorded in
the dose groups. No treatment related necropsy findings were observed.
There were no adverse effects indicated in regards to food consumption
or body weight development. Regarding FT3, FT4 and TSH level there was
no test item effect indicated.
There was no significant differences in
thyroid weights or histopathology among the groups. Number of
implantations, intrauterine mortality and sex distribution of the
fetuses were not influenced by the treatment. There were no test item
related adverse effects on the fetal- and placental weight, ano-genital
distance, external and visceral development of fetuses. There were no
test item related malformations found. The number of litters with
malformations was one in the control and one in the high dose group.
There was no increase of variations during fetal examinations indicated.
Based on these observations the No Observed
Adverse Effect Level (NOAEL) was determined as follows:
NOAEL (maternal toxicity): 1000 mg/kg bw/day
NOAEL (developmental toxicity including
teratogenicity): 1000 mg/kg bw/day
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