2-Propenoic acid, 2-[2-(ethenyloxy)ethoxy]ethyl ester

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Remarks:

pre-natal development toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

In life phase: February 4 to July 16, 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

In the measurement of T3 on March 19, standard solutions were not appropriately measured. Remeasurement was performed on these samples, therefore, this event was not considered to affect the quality or integrity of the study results.

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

451-690-9

EC Name:

-

Cas Number:

86273-46-3

Molecular formula:

C9H14O4

IUPAC Name:

2-[2-(ethenyloxy)ethoxy]ethyl prop-2-enoate

Test material form:

liquid

Details on test material:

Name: 2-(2-Vinyloxyethoxy) ethyl acrylate
Synonym: VEEA
Lot No: 8K15
Purity: 99.6%
Supplier: Study sponsor
Storage conditions: Refrigerated

Specific details on test material used for the study:

Name: 2-(2-Vinyloxyethoxy) ethyl acrylate
Synonym: VEEA
Description: Colourless liquid
Lot No: 8K15
Purity: 99.6%
Supplier: Study sponsor
Storage conditions: Refrigerated

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Japan, Inc.
- Age at study initiation: 9 weeks
- Weight at study initiation: females weighed 186 to 234 g,
- Housing: Metal bracket cages (260 W x 380 D x 180 H, mm), with wire mesh floors. For females with successful copulation, small trays with bedding for experimental animals.
- Number of animals per cage: Two females during quarantine and mating period, 1 male during mating period, 1 female after group assignment; and 2 (1 male and 1 female) during mating
- Diet (e.g. ad libitum): Pellet diet, CRF-1, supplied freely from metal feeders.
- Water (e.g. ad libitum): Sapporo-City tap water, Supplied freely from the automatic watering system.
- Acclimation period: The period from animal receipt to the completion of obtaining pregnant females and group assignment was designated as the quarantine and mating period on a computer
system. Quarantine period: from the day of receipt ( quarantine and mating day 1, to quarantine and mating day 6 Acclimatization period: the period up to initiation of mating, including the quarantine period.

DETAILS OF FOOD AND WATER QUALITY:
Food quality: The diet of the lots used in this study was analyzed for contaminants that may affect the study. The analysis results of all items were within the acceptable ranges.
Drinking water: Samples of drinking water were collected at the end of the piping system of the animal room used in this study on January 7, and July 1, 2019, and analyzed for contaminants that may affect the study. The analysis results of all items were within the acceptable ranges.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 3°C (actual range 21°C to 24°C)
- Humidity (%): 50% +/- 20% (actual range 38% to 57%)
- Air changes (per hr): 10 to 15
- Photoperiod (hrs dark / hrs light) 12 hours artificial lighting (from 8:00 to 20:00):

IN-LIFE DATES: From: 30th January, 2019 To: 16th July, 2019
Study Initiation: January, 28, 2019
Start of mating: 4th February, 2019
Start of administration: 11th February, 2019
Start of intrauterine observation at term: 25th February, 2019
End of fetal examination: 16th July, 2019
Study completion: 20th September, 2019

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Preparation method: A required amount of the test article was accurately weighed out for each dose level, to which the vehicle was added to obtain each prescribed concentration, and the mixture was stirred with a stirrer to dissolve the test article.
Preparation frequency: Prepared 4 times at intervals of 7 days, and used within 7 days after preparation.
Storage conditions: Dosing solutions were placed in light-resistant containers, and stored at room temperature (actual range 21.0°C to 22.1°C).

ADMINISTRATION:
Method: Dosing solution was administered into the stomach by oral gavage using a disposble gastric tube and a disposable syringe.
Individual dose volume was calculated based on the body weight on the measurement day closest to the day of administration.

VEHICLE
- Name: Corn Oil
- Justification for use and choice of vehicle (if other than water): Test article stable in vehicle.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Confirmation of stability of dosing solutions:
Before the start of administration, the 2.5 and 100 mg/mL preparations were confirmed to be stable for 8 days ( counted from the day of preparation designated as day 0) at room temperature.

Confirmation of concentrations of dosing solutions: The concentrations of the test article in the dosing solutions of all concentrations were analyzed by HPLC at the first and final preparation. The analysis results confirmed that the concentrations of the dosing solutions were appropriate.

Instruments:
High performance liquid chromatography (HPLC) Waters system
Alliance Separations Module: e2695; Waters Corporation
UV-VIS Detector: 2489; Waters Corporation
HPLC Data processor: Empower 3; Waters Corporation

Reference standard
Name: 2-(2-Vinyloxyethoxy) ethyl acrylate
Synonym: VEEA
Lot No.: 8K15
Storage conditions: Refrigeration (actual range 3.0°C to 4.0°C), lightresistant, and airtight

HPLC conditions:
Column: Unison UK-C18, 3 μm, 4.6 mm I.D. x 250 mm, Imtakt Corporation
Mobile phase: Acetonitrile/0.1 % phosphoric acid solution (1:1)
Autosampler rinse solution: Acetonitrile/ultrapure water (1:1)
Flow rate: 0.8 mL/min
Wavelength: 211 nm
Column temperature: 40°c
Injection volume: 10 µL
Autosampler temperature: 10°c
Run time: 11 minutes

Criteria:
Stability test:
(1)At preparation: The content should be 100% ± 10.0%, RSD should not exceed 5.0%.
After storage: The remaining rate should be 100% ± 10.0%, RSD should not exceed 5.0%.
(2)Confirmation test of concentration:
The content should be 100% ± 10.0%, and the RSD should not exceed 5.0%.
(3)System suitability test:
The RSDs of the peak area and retention time should not exceed 2.0%.

Results:
(1) Stability test: The results met the criteria both at preparation and after storage
(2) Confirmation test of concentration: The results met the criteria.
(3) System suitability test: The results met the criteria (RSDs: 0.0% to 0.5%).

Details on mating procedure:

MATING AND ASSIGNMENT OF MATED FEMALES TO TEST GROUPS:
Animals used: Animals that showed no abnormality in body weight gain or clinical signs during the quarantine and mating period were selected for this study.

Age of animals at initiation of mating: After the end of quarantine ( quarantine and mating day 6), mating was started at 29 weeks of age in males and at 9 weeks of age in females.

Mating procedure: Vaginal smears were taken from females for microscopic examination. Females showing proestrous vaginal smears were transferred to males' cages in the early evening and paired overnight with males on a 1: 1 basis. On the following morning, vaginal plugs and sperm in vaginal smears of the females were examined. Successful copulation was confirmed by the presence of sperm in vaginal smears. The day on which copulation is confirmed was designated as gestation day (GD) 0.

Mating period: The mating procedure was repeated during 11 days until the required number of mated females (24 females/group) was attained. Males were observed for clinical condition until the required number of mated females was obtained, and females were also observed until copulation.

Group assignment: On the day on which evidence of copulation was detected, females were weighed and distributed to test groups so that group means and standard deviations of body weight were as equal as possible, using the computer system (MiTOX).

Duration of treatment / exposure:

The animals were dosed once daily from Gestation Day (GD) 6 to GD 19.

Frequency of treatment:

Once daily

Duration of test:

Start of mating: 4th Feb, 2019
End of fetal examination: 16th July, 2019

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day

Remarks:

Control

Doses / concentrations 2

Dose / conc.:

10 mg/kg bw/day

Remarks:

Low dose

Doses / concentrations 3

Dose / conc.:

60 mg/kg bw/day

Remarks:

Middle dose

Doses / concentrations 4

Dose / conc.:

400 mg/kg bw/day

Remarks:

High dose

No. of animals per sex per dose:

Test Group: Dose mg(kg) Concentration (mg/mL) Dose volume (ml/kg) Number of mated females
Control 0 0 4.0 24
Low Dose: 10 2.5 4.0 24
Middle dose: 60 15 4.0 24
High dose 400 100 4.0 24

Control animals:

yes, concurrent vehicle

Details on study design:

Details on study design:
A prenatal developmental toxicity study was performed to investigate potential effects of VEEA on dams and embryo-fetal organogenesis and development. VEEA was orally administered to Crl:CD(SD) rats, 24 mated females per group, at 0, ( control), 10, 60, and 400 mg/kg/day from gestation days 6 to 19. Fetuses were removed from the uterus at the necropsy of dams on gestation day 20, and external, visceral and skeletal examinations were performed.

Rational for dose selection:
In the combined repeated dose toxicity study with the reproduction and developmental toxicity study of the test article, the test article was administered by oral gavage at 0, 50, 140, and 400 mg/kg to 12 female rats per group from 14 days before the start of mating to 5 days after parturition. In that study, thickening of the limiting ridge of the stomach or the forestomach mucosa was noted at 50 mg/kg and higher doses and salivation was noted at 400 mg/kg in dams; however, no effects of the test article administration were noted on the reproductive performance of parental animals or on the offspring.

Based on these results, the high dose was set at 400 mg/kg, which is expected to cause clear changes in dams, and the middle and low doses were set at 60 and 10 mg/kg, respectively, with a common ratio of approximately 6.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: From GD 0 to the day of necropsy.
Animals were examined for mortality, external appearance, behavior, and other changes. Animals were checked twice daily during the administration period (before and after dosing), and once daily during the other periods.
- Frequency: Twice daily during the administration period (before and after dosing), and once daily during the other periods

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: From GD 0 to the day of necropsy.
- Frequency: Twice daily during the administration period (before and after dosing), and once daily during the other periods

BODY WEIGHT: Yes
- Time schedule for examinations: Body weight measurements were performed on GD's 0, 3, 6, 9, 12, 15, 18 and 20.
- Body weight game calculation: Body weight on GD 6 was subtracted from each value measured on and after GD 9 to calculate the body weight gain.
- Adjusted body weight: Adjusted body weight = body weight on GD 20 - gravid uterine weight.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Measurement days: On GDs 0, 3, 6, 9, 12, 15, 18, 20
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

NECROPSY:
Time schedule: Animals were necropsied on GD 20
Method: After observation of external appearance and blood collection under anesthesia with isoflurane, animals were euthanized by exsanguination and grossly examined for organs and tissues. The thyroid and gross lesions were fixed and preserved in I 0% neutral buffered formalin.

POST-MORTEM EXAMINATIONS: Yes
Measurements performed: Thyroid weight measurements and histopathology of the thyroid.

OTHER:
Measurement of serum hormone concentration was examined in all animals at necropsy

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes (at necropsy on GD 20)
Examinations included:
Gravid uterine weight, the numbers of corpora lutea, implantations, live fetuses, dead or resorbed embryos and fetuses, weight of live fetuses, and sex of live fetuses.

At necropsy of maternal rats, the ovaries and uteri were removed, and gravid uterine weight was measured with an electronic balance. Then, the uterine wall was dissected to observe the intrauterine condition and life and death of embryos and fetuses, and condition of their placentas, and the number of implantations was recorded. Live fetuses were removed from the uterus and individually weighed with an electronic balance. Live fetuses were sexed by external observation of the length between the anus and genitalia. When comparing the sex determination results and those based on the internal reproductive organs, there was no inconsistency in any fetuses. The number of corpora lutea in the ovaries was recorded. The ovaries and uterus after examination were preserved in 10% neutral buffered formalin by litter. The placentas after examination for anomalies were discarded. The uterus of the animal No. 50262, in which no uterine implants were grossly apparent, was stained with 10% ammonium sulfide solution and implantation sites were detected.

Fetal examinations:

Anogenital distance:
Animals measured: All live fetuses
Method: The length between the anus and genitalia (AGD) of each fetus was measured and recorded. Litter mean AGD for each sex was calculated. In addition, litter mean AGD was divided by the cube root of its litter mean body weight by sex.

Fetal external examination:
Animals examined: All live fetuses
Method: At term of pregnancy, live fetuses were examined for external anomalies. After the examination, fetuses were euthanized by an intraperitoneal injection of pentobarbital sodium. Then, approximately one-half of the live fetuses in each litter was fixed in Bouin's solution for visceral examination. The remaining half of the fetuses were eviscerated, and then fixed in 99.5% ethanol for skeletal examination. When eviscerating the fetuses for skeletal examination, sex of the internal reproductive organ and presence or absence of malposition of the testis of males were recorded. The observation revealed no malposition of the testis in any male fetuses.

Calculation: The following indices were calculated:
Incidence of feta! external anomalies (%) = (number of fetuses showing external anomalies/ number of fetuses examined) x 100

Incidence of dams having fetuses with external anomalies = number of dams having fetuses with external anomalies / number of litters examined

Fetal visceral examination:
Animals examined: Visceral examination was performed for all fetuses fixed in Bouin's solution.

Method: Fetuses fixed in Bouin's solution were transferred to 70% ethanol before examination and then examined for presence or absence of visceral variations and anomalies macroscopically or under a stereoscopic microscope. The head was examined according to Wilson's free-hand sectioning method3l, the thoracic region was examined according to Nishimura's microdissection method4l, and the abdominal region was examined by the microdissection method. After the completion of these examinations, the fetuses were individually stored in 70% ethanol.

Calculation:
Incidence of fetal visceral variations (%) = (number of fetuses with visceral variations/ number of fetuses examined) x 100
Incidenece of litters with fetal visceral variations = number of dams having fetuses with visceral variations / number of litters examined.

Fetal skeletal examination:
Animals examined: Skeletal examination was performed for all skeletal specimens prepared.

Method: All fetuses fixed in 99.5% ethanol in all test groups were stained with alizarin red S, and then penetrated by KOH aqueous solution, followed by successive immersion in 50% and 70% glycerin aqueous solutions to prepare clear skeletal specimens. The numbers of ossified bones were counted under a stereoscopic microscope and the fetuses were examined for presence or absense of skeletal variations and anomalies.

Calculation:
Incidence of fetal skeletal variations (%) = (number of fetuses with skeletal variations / number of fetuses examined ) x 100
Incidence of fetal skeletal anomalies (%) = (number of fetuses with skeletal anomalies / number of fetuses examined) x 100
Incidence of litters with fetal skeletal variations = number of dams having fetuses with skeletal variations / number of litters examined
Incidence of litters with fetal skeletal anomalies = number of dams having fetuses with skeletal anomolies / number of litters examined

Statistics:

Statistical analyses were performed using the computer system (MiTOX). The data in the test article groups and those in the control group were compared using the procedures shown below. In the feta! data, litter averages were used as the unit for statistical evaluation.

Means and standard deviations were calculated for the results of the following data:
body weight, adjusted body weight, body weight gain, food consumption, gravid uterine weight, and thyroid weight of maternal rats, numbers of corpora lutea, implantations, live fetuses, and dead or resorbed embryos and fetuses, and weight of live fetuses (by sex), and degree of ossification, which were analyzed for homogeneity of variances by the Bartlett test.

Means and standard deviations were calculated for the results of the following data:
preimplantation loss, implantation index, postimplantation loss, postimplantation loss in early stage and that in late stage, incidences of feta! anomalies or variations, and incidence of anomalous placentas, which were analyzed by Steel's test to detect any statistically significant difference between the test article and control groups. Fisher's exact probability test was used for data on the feta! sex ratio and incidences of litters having fetuses with anomalies or variations and dams with anomalous placentas.

Statistically significance level was set at 5% for comparison analysis with the control group.

Indices:

Classification of dead or resorbed embryos and fetuses:
Embryo-fetal resorptions and deaths were classified into implantation sites and placental remnants (in the early stage of gestation after implantation) and macerated fetuses and dead term fetuses (in the late stage of gestation) according to the developmental stage at which they occurred.

Identification of live fetuses:
Calculation:
Individual identification of all live fetuses was performed in each litter. Preimplantation loss, implantation index, postimplantation loss, postimplantation loss in the early stage, postimplantation loss in the late stage, and incidence of anomalous placentas were calculated for each litter, and sex ratio and incidence of litters with anomalous placentas were calculated for each group by the following equations:

Preimplantation loss (%) = [ (number of corpora lutea ~ number of implantations) / number of corpora lutea] x 100

Implantation index (%) = (number of implantations/ number of corpora lutea) x 100

Postimplantation loss (%) = (number of dead or resorbed embryos and fetuses / number of implantations) x 100

Postimplantation loss in the early stage (%) = (number of early embryo-feta! deaths/ number of implantations) x 100

Postimplantation loss in the late stage (%) = (number oflate embryo-feta! deaths/ number of implantations) x 100

Sex ratio (%) = (total number oflive male fetuses / total number oflive fetuses) x 100

Incidence of anomalous placentas (%) = (number of anomalous placentas/ number of placentas examined) x I 00

Incidence of litters with anomalous placentas = number of dams with anomalous placentas/ number of litters examin

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

no effects observed

Description (incidence and severity):

No abnormal findings were noted in clinical observation in any animal before the start of administration.
During the administration period and on the necropsy day, no abnormal findings were noted in clinical observation in any animal before and after dosing. No deaths occurred in any test group.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No deaths occurred in any test group.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In the 400 mg/kg group, body weight was significantly lower that that in the control group from GD 15 to GD 20. In this group, adjusted body weight was also significantly low. In the 60 ro 10 mg/kg group, no significant differences were noted.

In the 400 mg/kg group, body weight gain was significantly lower than that in the control group throughout the administration period. In the 60 or 10 mg/kg group, no significant differences were noted.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

In the 400 mg/kg group, food consumption was lower than that in the control group throughout the administration period, with statistically significant differences from GD 9 to GD 18. In the 60 or 10 mg/kg group, no significant differences were noted.

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:

no effects observed

Description (incidence and severity):

No significant differences were noted in the absolute or relative thyroid weight of maternal rats in any test article group compared with that in the control group.

No significant differences were noted in the gravid uterine weight in any test article group compared with that in the control group.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

In the 400 mg/kg group, focal thickening of mucosa in the forestomach was noted in 15 maternal rats. In the 60 or 10 mg/kg group, no abnormalities were noted.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Histopathological findings of the thyroid:
Remnant of ultimobranchial body was occasionally noted in each gronp, which was considered unrelated to the test article administration because this is a congenital change. No other abnormalities were noted in any animal.

Histopathological findings: neoplastic:

not examined

Other effects:

effects observed, non-treatment-related

Description (incidence and severity):

Serum hormone concentration (T3, T4 and TSH):
In the 400 mg/kg group, serum T4 concentration was significantly higher than that in the control group; however no changes were noted in serum T3 or TSH concentration. In the 60 or 10 mg/kg group, no significant differences were noted in any serum hormone concentration.

Maternal developmental toxicity

Number of abortions:

no effects observed

Description (incidence and severity):

No significant differences were noted in the numbers of numbers of dead fetuses and live fetuses in any test article group compared with that in the control group.
All females with successful copulation were confirmed pregnant, and live fetuses were obtained from all of them except one (animal No. 50262) that had implantation sites only.

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

No significant differences were noted in the numbers of corpora lutea and implantations, preimplantation loss, implantation index, postimplantation loss in any test article group compared with that in the control group.

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Description (incidence and severity):

No significant differences were noted in the numbers of numbers of dead fetuses and live fetuses in any test article group compared with that in the control group.

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Description (incidence and severity):

All females with successful copulation were confinned pregnant, and live fetuses were obtained from all of them except one (animal No. 50262) that had implantation sites only.

Other effects:

no effects observed

Description (incidence and severity):

The examination of placentas showed no abnormalities in any test groups including the control group.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

60 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

other: Oral administration of test article to dams was considered to induce inhibition of body weight gain and food intake and thickening of the forestomach mucosa in dams at 400 mg/kg/day. The NOAEL was considered 60 mg/kg/day for dams.

Maternal abnormalities

Abnormalities:

no effects observed

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

No significant differences were noted for fetal weight for either sex in any test article group compared with that in the control group.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

No significant differences were noted in the numbers of dead fetuses and live fetuses any test article group compared with that in the control group.

Changes in sex ratio:

no effects observed

Description (incidence and severity):

No significant differences were noted in the fetal sex ratio in any test article group compared with that in the control group.

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

not examined

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

External anomalies noted were thread-like tail in one fetus (group mean incidence per litter: 0.26%) in the control group, and two runts (0.57%) in the 10 mg/kg group.

In the fetal or litter incidence of these anomalies, no significant differences were noted in any test article group compared with the control group. No anomalies were noted in the 60 or 400 mg/kg group.

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

A number of skeletal variations were noted in test and control groups.
In the fetal or litter incidences of these skeletal variations, no significant differences were noted in any test article group compared with the control group. There was no skeletal anomaly in any fetus in any test group.
No significant differences were noted in the mean numbers of ossifications of sacrocaudal centrum or stemebra in any test article group compared with the control group.

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

Visceral variations were noted as follows: thymic remnant in the neck in 5 (group mean incidence per litter: 2.70%), 7 (3.78%), 4 (2.48%), and 2 (1.29%) fetuses in the control, 10, 60, and 400 mg/kg groups, respectively. Left umbilical artery in 1 (0.60%) and 1 (0.52%) fetuses in the control and 60 mg/kg groups, respectively. In the fetal or litter incidences of these variations, no significant differences were noted in any test article group compared with the control group.

There was no visceral anomaly in any fetus in any test group.

Other effects:

no effects observed

Description (incidence and severity):

Anogenital distances of fetuses:
No significant differences were noted in AGD or AGD per cube root of body weight ratio in males or females in any test article group compared with that in the control group.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: The test article was considered to have no adverse effects on organogenesis and development of fetuses at doses up to 400 mg/kg/day

Fetal abnormalities

Key result

Abnormalities:

no effects observed

Overall developmental toxicity

Key result

Developmental effects observed:

no

Any other information on results incl. tables

A prenatal developmental toxicity study was performed to investigate potential effects of VEEA on dams and embryo-fetal organogenesis and development. VEEA was orally administered to Crl:CD(SD) rats, 24 mated females per group, at 0 ( control), 10, 60, and 400 mg/kg/day from GD 6 to GD 19.

In dams, food consumption, body weight and body weight gain during the administration period and adjusted body weight on GD 20 were low in the 400 mg/kg group, which were considered effects of the test article administration. In addition, necropsy revealed focal thickening of the forestomach mucosa, which was considered an effect of the test article administration because the same change was noted also in the combined repeated dose toxicity with reproduction/developmental toxicity study. In this group, serum T4 concentration was significantly high in dams. This was considered toxicologically insignificant because no changes were noted in the thyroid weight or serum TSH concentration, and histopathological examination of the thyroid revealed no abnormalities related to the test article administration. In the 10 or 60 mg/kg group, no changes related to the test article administration were noted in the dams.

In the uterine weight and examination of ovary and uterine content at necropsy on GD 20, no changes were noted in any test article group, and the embryo/fetal survival or fetal development was not considered affected at doses up to 400 mg/kg.

In fetal AGD, effects of the test article administration were not noted in males or females at doses up to 400 mg/kg. In external appearance of fetuses, 2 runts were observed in the 10 mg/kg group. This was not considered related to the test article administration because no runts were noted in the higher dose groups and there were no significant differences in its fetal or litter incidences compared with the control group.

Fetal visceral examination revealed no visceral anomalies in any test article group.

Visceral variations of thymic renmant in the neck or left umbilical artery were occasionally noted in each group. These were considered unrelated to the test article administration because there were no significant differences in their fetal or litter incidences compared with the control group.

In fetal skeletal examination, no anomalies were noted in any test article group. Skeletal variations including dumbbell ossification of sternebra, short 13th rib, short thoracolumbar supernumerary rib, and bipartite/dumbbell ossification of thoracic centrum were noted in each group. These were considered unrelated to the test article administration because there is no significant difference in their fetal or litter incidences compared with the control group. In degrees of ossification of fetuses, no effects of the test article administration were noted.

On the basis of these results, oral administration of VEEA to dams was considered to induce inhibition of body weight gain and food intake and thickening of the forestomach mucosa in dams at 400 mg/kg/day, and was not considered to have any effect on the fetuses at doses up to 400 mg/kg/day.

Therefore, the no-observed adverse effect level of VEEA was considered 60 mg/kg/day for dams, and 400 mg/kg/day for fetuses under the present study conditions. In addition, VEEA was considered to have no adverse effects on organogenesis and development of fetuses at doses up to 400 mg/kg/day.

Applicant's summary and conclusion

Conclusions:

Oral administration of VEEA to dams was considered to induce inhibition of body weight gain and food intake and thickening of the forestomach mucosa in dams at 400 mg/kg/day, and was not considered to have any effect on the fetuses at doses up to 400 mg/kg/day.

On the basis of these results, the no-observed adverse effect level of VEEA was considered 60 mg/kg/day for dams, and 400 mg/kg/day for fetuses under the present study conditions. In addition, VEEA was considered to have no adverse effects on the fetal organogenesis and development at doses up to 400 mg/kg/day.

Executive summary:

A prenatal developmental toxicity study was performed to investigate potential effects of VEEA on dams and embryo-fetal organogenesis and development. VEEA was orally administered to Crl:CD(SD) rats, 24 mated females per group, at 0 ( control), 10, 60, and 400 mg/kg/day from gestation days 6 to 19. Fetuses were removed from the uterus at the necropsy of dams on gestation day 20, and external, visceral and skeletal examinations were performed.

In dams, food consumption, body weight and body weight gain during the administration period and adjusted body weight on gestation day 20 were low and focal thickening of the forestomach mucosa was noted in necropsy in the 400 mg/kg group. In the 10 or 60 mg/kg group, no changes related to the test article administration were noted in the dams.

In thyroid function related hormones, weight and histopathology of the thyroid, and uterine weight and ovary and uterine content at necropsy on gestation day 20, no effects of the test article administration were noted at doses up to 400 mg/kg.

In AGD, external appearance, and visceral and skeletal examination of fetuses, no changes related to the test article administration were noted.

On the basis of these results, oral administration of VEEA to dams was considered to induce inhibition of body weight gain and food intake and thickening of the forestomach mucosa in dams at 400 mg/kg/day, and was not considered to have any effect on the fetuses at doses up to 400 mg/kg/day.

On the basis of these results, the no-observed adverse effect level of VEEA was considered 60 mg/kg/day for dams, and 400 mg/kg/day for fetuses under the present study conditions. In addition, VEEA was considered to have no adverse effects on the fetal organogenesis and development at doses up to 400 mg/kg/day.