3-Methoxy-3-methylbutyl acetate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-07-10 to 2007-08-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-Methoxy-3-methylbutyl acetate

EC Number:

700-408-5

Cas Number:

103429-90-9

Molecular formula:

C8H16O3

IUPAC Name:

3-Methoxy-3-methylbutyl acetate

Test material form:

liquid

Test animals

Species:

rat

Strain:

other: Crl: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 9 weeks
- Weight at study initiation: males: 322.8 – 363.7 g; females: 199.9 – 238.7 g
- Housing: stainless steel cages with wire-mesh floor; after copulation females were placed in polycarbonate cages with wood chip bedding. 1 animal/cage, 1 female and 1 male/cage during mating period
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 8 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 25
- Humidity (%): 40 - 70
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: Carboxymethylcellulose sodium (CMC-Na) of 1.0% with Tween 80 of 0.1% aqueous solution

Details on exposure:

The test substance was repeatedly administered once daily in the morning by oral gavage using a syringe connected to a Nelaton catheter.
Dosing volume was10 mL/kg.

Details on mating procedure:

Females except recovery groups were placed into male´s cages in the afternoon on day 15 evening and paired overnight on a 1:1 basis with a limit of 14 days. Copulation was verified the following morning by the presence of vaginal plugs or sperms in the vaginal smears, and this day was designed pregnancy as day 0. The followings were calculated from these data.
Paring days until copulation
Copulation index: (Number of impregnated males/Number of mated pairs) x 100
Fertilization index: Number of pregnant females/Number of females in copulated pairs) x 100
Conception index: (Number of implantation sites/Number of corpora lutea) x 100
Preimplantation loss index: [(Number of corpora lutea – Number of implantation sites)/Number of corpora lutea] x 100
Post implantation loss index: [8Number of implantation sites – Number of live pups on postnatal day 0)/Numer of implantation sites] x 100

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Samples were taken (n=1) from the middle layer of 0.25, 1.5 and 10.0 w/v% formulations immediately after preparation. These samples were pretreated and measured (n=1) with gas chromatography (GC).

Duration of treatment / exposure:

Dosing period form males was 42 days from two weeks before mating to the day before necroscopy throughout the mating period. For females it was 41 to 47 days, two weeks before mating to 4 days in the nursing period.

Frequency of treatment:

Once daily in the morning

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

25 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

150 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
A 14-day repeated oral dose toxicity study was performed with each 3 male and female Crj:CD(SD) rat of 7 weeks old at 4 doses of 15, 60, 250 and 1000 mg/kg/day. As a result, increases in WBC in the 1000, 250 and 15 mg/kg/day increases in GOT, GPT, ALP, LDH, CPK and neutral fat and increases or decreases in cholinesterase in all dose groups were observed; however, they were slight changes, single occurrence or no dose-related changes. Therefore, the high dose was set at 1000 mg/kg/day and lower doses of 150 and 25 mg/kg were set for the present study.

Positive control:

no

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Not specified

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Male animals were observed twice a day, i.e., before dosing and after dosing from day 1 of administration to the day before necropsy, and once on the day of necropsy. Female animals were also observed twice a day from day 1 to day 4 of nursing period including delivery and nursing conditions, and once on day 5 of nursing period of the day of necropsy. During the recovery period, all animals were observed once a day.
Detailed Clinical Observations:
The detailed examination in all animals was performed ad blind tests before dosing and once a week thereafter. Males and females during the mating period were not examined. Mated females were observed in week 1 to 5 and after delivery. During the recovery period, the observation was performed once a week.

BODY WEIGHT: Yes
- Time schedule for examinations: Body weight was measured once during the acclimation period and once at allocation to groups in all animals, and on the treatment days of 1, 3, 7, 14, 21, 28, 35, 42, 43 (necropsy) in females of the recovery groups and all males. Body weights of the other females were measured on days 1, 3, 7 and 14 before gestation, days 0, 7, 14, 17 and 20 during the gestation period and days 0 (delivery), 4 and 5 (necropsy). In the recovery period, all animals were measured on days 1, 3, 7, 14 and 15 (necropsy).

FOOD CONSUMPTION:
- Food consumption was measured on the treatment days of 1, 3, 7, 14, 21, 28, 35 and 42 in females of the recovery groups and all males. Food intakes of the females were measured on days 1, 3, 7 and 14 before gestation, on days 0, 7, 14, 17 and 20 during the gestation period and on days 0 and 4 after delivery. In the recovery period food consumption was measured on days 1, 3, 7 and 14. Mean food consumption per day was calculated from the deference between each measured day and the next measured day. All animals were fasted from the afternoon of the day before necropsy.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at completion of the dosing period and at completion of the recovery period
- Anaesthetic used for blood collection: Yes. Blood plasma samples were obtained by blood sampling from the abdominal aorta under ether anesthesia
- Animals fasted: Yes. Overnight fasting (16 to 20 hr)
- How many animals: in five males and five females whose delivery days were closed in each group, and all males and females in the recovery groups.
- Parameters checked in table [No. 2] were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Serum samples were separated from blood samples collected at the same times as those for haematology examinations.
- Animals fasted: Yes. Overnight fasting (16 to 20 hr)
- How many animals: in five males and five females whose delivery days were closed in each group, and all males and females in the recovery groups.
- Parameters checked in table [No.3] were examined.

OTHER:
- Sensorimotor Function:
Each five males and five females in all groups were examined in the final week and on day 4 of the nursing period before fasting, respectively, or five females whose delivery days closed in each group were examined when the number of females was less than five in a group. Recovery groups were examined in the final week of the dosing period. In the recovery period locomotor activity were counted in females of the vehicle control and 1000 mg/kg groups since significant differences were noted in females of the 1000 mg/kg group in the dosing period.

- Organ weight:
The weights of the following organs were measured in all animals. The relative organ weight per 100 g of body weight was calculated based on the body weight at the time of necropsy:
Liver, heart, kidney, testes, epididymides, brain, spleen, thymus and adrenals.

Oestrous cyclicity (parental animals):

Vaginal smears of all females were taken in every morning from day 1 to day 15 of the administration period, and stained with giemsa and examined microscopically. Mean cycle length was calculated between an estrus and next estrus stage.

Sperm parameters (parental animals):

not specified

Litter observations:

At day of birth, numbers of pups born, stillborns and dead newborns, and number of live pups, sex ration and external features of live newborns were recorded for each litter. During the nursing period, newborns were observed daily for general condition and mortality. Body weights of each sex were measured at the day of birth and on day 4 after birth.
Birth index: (Number of live pups on postnatal day 0/Number of implantation sites) x 100
Viability index on day 0: (Number of live pups on postnatal day 0/Number of pups born) x 100
Sex ration: Number of live males/Number of live females
External anomaly index: (Number of live pups with external anomalies/Number of live pups examined) x 100
Viability index on day 4: (Number of live pups on postnatal day 4/Number of live pups on postnatal day ) x 100

Postmortem examinations (parental animals):

GROSS PATHOLOGY: Yes
All animals were subjected to the detailed gross necropsy including body surface, all orifices, subcutis, cranial, thoracic, abdominal and pelvic cavities, and the contents. Corpora lutea in the ovaries and implantation sites in incised uterus were counted.

HISTOPATHOLOGY: Yes
The following organs and tissues were taken in all animals:

Category Organs and Tissues
Respiratory system Trachea and lungs
Digestive system Stomach, intestine (duodenum to rectum, with Peyer´s patches) and liver
Cardiovascular system Heart
Urinary system Kidneys and urinary bladder
Reproductive system Testes, epididymides, prostate, seminal vesicle, ovaries, uterus and vagina
Nervous system Brain (cerebrum, cerebellum and pons), spinal cord and sciatic nerve
Hematopoietic and
lymphatic system Bone marrow (femur), axillar and mesenteric lymph nodes, spleen and thymus
Endocrine system Pituitary gland, thyroids (with parathyroids) and adrenals


Trachea, lungs and urinary bladder were filled with 10% neutralized buffered formalin before taken. Stomach and intestines were filled and fixed with 10% neutralized buffered formalin and the contents were wash away with water. All organs/tissues were preserved in 10% neutralized buffered formalin. However, testes and epididymides were fixed in Bouin´s solution.

Postmortem examinations (offspring):

not specified

Statistics:

Data regarding body weights of parent animals (excluding those at the time of necropsy), food intakes, FOB metrical data (grip strength and locomotor activity count), hematological examinations, blood chemical examinations, organ weights, mean estrous-cycle-length, pairing days until copulation, gestation length, number of corpora lutea and implantation sites, number of pups born, stillborn and live pups and body weights were analyzed using the Bartlett´s test for homogeneity of variance. If the variances were homogeneous at a significance level of 5%, one was analysis of variance was performed. If there was a significant difference in this analysis, the difference between the vehicle control group and each of the treatment groups was analyzed by the Dunnett´s test. If the variances were not homogeneous, the Kruskal-Wallis´s test was used. If there was a significant difference in this analysis, the difference between the vehicle control group and each of the treatment group was analyzed by the nonparametric Dunnett´s test.

FOB numerical data (defecation and urination) was analyzed using the Kruskal-Wallis´s test. If there was a significant difference in this analysis, the difference between the vehicle control group and each of the treatment groups was analyzed by the nonparametric Dunnett´s test.
Copulation, fertilization, conception and delivery dam index and sex ratio of offspring were analyzed by the Fisher´s exact probability test. Implantation index, pre-implantation loss index, post-implantation loss index, birth index, viability index on day 0, external anomaly index and viability index on day 4 were analyzed by the Kruskal-Wallis´s tst. Body weights of pup in each sex were treated as a litter unit.

Reproductive indices:

Paring days until copulation
Copulation index: (Number of impregnated males/Number of mated pairs) x 100
Fertilization index: (Number of pregnant females/Number of females in copulated pairs) x 100
Conception index: (Number of implantation sites/Number of corpora lutea) x 100
Preimplantation loss index: [(Number of corpora lutea – Number of implantation sites)/Number of corpora lutea] x 100
Post implantation loss index: [(Number of implantation sites – Number of live pups on postnatal day 0)/Number of implantation sites] x 100

Offspring viability indices:

Birth index: (Number of live pups on postnatal day 0/Number of implantation sites) x 100
Viability index on day 0: (Number of live pups on postnatal day 0/Number of pups born) x 100
Sex ration: Number of live males/Number of live females
External anomaly index: (Number of live pups with external anomalies/Number of live pups examined) x 100
Viability index on day 4: (Number of live pups on postnatal day 4/Number of live pups on postnatal day ) x 100

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Males: Salivation just after dosing was observed in all animals of the 1000 mg/kg group. No abnormalities in other groups.
Female: No abnormalities observed before mating period. Salivation was observed in four animals of the 1000mg/kg group. One animal in the vehicle control group showed staining on the lower abdomen continuously from delivery, and all her pups died on day 2 of the nursing period. In the 150 mg/kg group, although abnormalities were noted during the nursing period, one pup died in one animal just after delivery. Salivation was observed in one animal, and staining on the lower abdomen and around the vagina in other one animal was observed and all her pups died on day 1 of nursing period in the 1000 mg/kg group. Salivation was observed only just after dosing in three animals of the 1000 mg/kg recovery group.
During Recovery Period: No abnormalities were noted in all groups of each sex.

Salivation was observed in the 1000 mg/kg groups only after treatment, and it possibly related to the taste of the substance and was not considered to be toxicologically significant.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One female died on day 23 of the gestation period in the vehicle control group. Foamy substance in the lumen of the trachea, dark reddish change in the lungs, recessed region of the mucosa in the forestomach, enlargement of the adrenals and hydrothorax were observed in the necropsy, and the cause of death was considered to be administration error.

Mortality of pups is documented in the robust study summary in the endpoint "Toxicity to reproduction"

Body weight and weight changes:

not specified

Description (incidence and severity):

During Dosing Period
Males: No abnormalities were noted.
Females: Significant lower body weights compared to the vehicle control group was noted in the 1000 mg/kg group on day 4 of the nursing period. Abnormal body weights were not noted in other groups.
During Recovery Period
No abnormalities were noted in all groups of each sex.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

During Dosing Period
Males: Abnormalities were not noted in all groups
Females: Significant decreases in food consumption in the 25 mg/kg group on day 17 of the gestation period and in the 1000 mg/kg group on day 3 of the administration period before mating, on day 17 of gestation period and on day 4 of the nursing period were not compared to the vehicle control group. No abnormalities were noted in other groups.
During Recovery Period
Males: Significant increases in food consumption were noted in the 1000 mg/kg recovery group on day 3.
Females: No abnormalities were noted in the 1000 mg/kg recovery group.

Food consumption was decreased without body weight changes in females of the 1000 mg/kg group on a day 3 of the treatment and on day 17 of the gestation periods. These food consumption were not considered to be of no toxicologically significant.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

At Termination of Dosing Period
Males: RBC was significantly decreased in the 1000 mg/kg group. No abnormalities were noted in the other groups.
Females: MCHC was significantly increased in the 25 mg/kg group. Significant decreases in RBC, Hb and Ht and a reduction in PT were noted in the 1000 mg/kg group. Abnormalities were not noted in other groups.
At Termination of Recovery Period
Males: No abnormalities were noted in the 1000 mg/kg group.
Females: A significant reduction in PT was noted in the 1000 mg/kg recovery group.

PT was reduced in females of the 1000 mg/kg group and this observation was not considered to be toxicologically significant.
Decreases in RBC in males and females, decreases in Hb and Ht in females were noted in the 1000 mg/ kg groups, and they were considered to be treatment-related.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

At Termination of Dosing Period
Males: No abnormalities were noted.
Females: A significant decrease in total protein in the 150 mg/kg group, increases in IP in the 150 and 1000 mg/kg groups and an increase in total cholesterol and a decrease in chloride in the 1000 mg/kg group were noted. In the other group, abnormalities were not noted.
At Termination of Recovery Period
Males: Creartinine was significantly decreased in the 1000 mg/kg recovery group.
Females: No abnormalities were noted in the 1000 mg/kg recovery group.

Increase in IP in females of the 150 and 1000 mg/kg groups and an increase in total cholesterol and a decrease in chloride in females of the 1000 mg/kg group were noted; however, they were not considered to be treatment-related since liver and kidney weights were not affected, and any histopathological changes were not noted in these organs.

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, non-treatment-related

Description (incidence and severity):

During Dosing Period
Males: No abnormalities were noted in all groups.
Females: Locomotor activity count in 50-60 min was significantly decreased in the 1000 mg/kg recovery group in week 6. No abnormalities were noted in other groups.
During Recovery Period
Males: Not examined.
Females: Locomotor activity count in 50-60 min was significantly increased in the 1000 mg/kg recovery group in week 2.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

At Termination of Dosing Period
Males: Mineralization in the Peyer´s patches in the jejunum in one animal microgranuloma in the liver in two animals, focal myocarditis in the heart in three animals and cyst formation in the medulla of the kidney in one animal were observed in the vehicle control group. Diffuse atrophy of the seminiferous tubules in the testis and decreased spermatozoa in the lumen, germ cell debris in the lumen and spermatic granuloma in the epididymis in one anima and capsulitis in the spleen in one animal were observed in the 25 mg/kg group. Mineralization in the Peyer´s patches in jejenum in one animal and cyst formation in the pars distalis of the pituitary gland in one animal were observed in the 1000 mg/kg group. No abnormal signs were observed in other group.

Females: Hyperplasia of the squamous epithelium in the limiting ridge of the forestomach in one animal, mineralization in the Peyer´s patches in the jejenum in one animal and cyst formation in the pars distalis of the pituitary gland in one animal were observed in the vehicle control group. Hyperplasia of the squamous epithelium in the limiting ridge of the forestomach in one animal, cyst formation in the medulla with basophilic tubules (unilateral) and mineralization in the pelvis (unilateral) of kidney in one animal, cyst formation in the vagina in two animals and atrophy of the thymus in one animal were observed in the 1000 mg/kg group. In one dead animal showed edema and thrombus in the lung, ulcer in the forestomach, focal necrosis of the hepatocytes in the liver, thrombus in the heart and kidney, atrophy of the spleen and thymus and hypertrophy of the cortex in the adrenal were observed in the vehicle control group. No abnormalities were observed in other groups.

At Termination of Recovery Period
Males: Necrosis of the fundic mucosa in the glandular stomach was observed in one animal of the 1000 mg/kg recovery group.
Females: Microgranuloma in the liver was observed in one animal and pelvic dilatation in the kidney in one animal were observed in the vehicle control recovery group. No abnormalities were observed in the 1000 mg/kg recovery group.


Dams which All Pups Died:
Hyperplasia of the squamous epithelium in the limiting ridge of the forestomach, vacuolization of the hepatocytes in the liver, vacuolization of the tubular epithelium in the kidney, atrophy of the thymus and fine cauolization of the zona fascilita in the adrenal were observed in on animal of the 150 mg/kg group. Edema in the submucosal layer, focal hyperplasia of the squamous epithelium and hyperplasia of the squamous epithelium in the limiting ridge of the forestomach, atrophy of the fundic mucosa in the glandular stomach, vacuolization of the tubular epithelium in the kidney, atrophy of the thymus and fine vacuolization of the zona fasciculate and hypertrophy of the cortex in the adrenal were observed in one animal of the 1000 mg/kg group.
Non-pregnant Female
No abnormalities were observed in two animals of the 25 mg/kg group and one animal of the 150 mg/kg group.

Mineralization in the Peyer´s pateches in the jejenum and cyst formation in the pars distalis of the pituitary gland in males and hyperplasia of the squamous epithelium in the limiting ridge of the forestomach, cyst formation in the medulla with basophilic tubules and mineralizaiton in the pelvis of the kidney, cyste formation in the vagina and atrophy of the thymus were observed in the 1000 mg/kg groups. These were single occurrence and also observed in the vehicle control groups. Therefore, they were not considered to be treatment related. The other changes did not show dose-relationships and were not considerd to be treatment-related.

Other effects:

not specified

Description (incidence and severity):

Males: Defecation was significantly increased in the 150 mg/kg group in week 5. All other animals showed no abnormalities.
Females: Urination was significantly decreased in the 25, 150 and 1000 mg/kg groups in week 1. No abnormalities were noted in other groups.This was not considered to be toxicologically significant since it related to the high value of the vehicle control group.

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

Abnormal mean estrous-cycle length and estrous stages were not noted in all groups.

Reproductive function: sperm measures:

not specified

Reproductive performance:

no effects observed

Description (incidence and severity):

Copulation was done in all dosing groups. The numbers of non-pregnant animals per group were two and one in the 25 and 150 mg/kg groups, respectively. Each conception index were 83.3 and 91.7%. In the vehicle control and 1000 mg/kg groups, conception indexes were 100%. Pairing days until copulation, copulation index, numbers of corpora lutea and implantation sites, implantation index, preimplantation less index, postimplantation loss index, gestation period, delivery index and delivery dam index showed no abnormalities.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

Repeated dose toxicity

Effect level:

150 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Decreases were noted in RBC in males and females dosed at the highest dose level (1000 mg/kg bodyweight); decreases in hemoglibin and hematocrit values were noted in females in the 1000 mg/kg group also. No adverse effects seen at 150 mg/kg.

2

Dose descriptor:

NOAEL

Remarks:

Reproductive effects

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

Results: F1 generation

General toxicity (F1)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Subnormal temperature was observed in litters observed poor nursing in the vehicle control and 1000 mg/kg groups. Viability index on day 4 in the vehicle control and 1000 mg/kg groups were 88.9 and 84.1% respectively, without significant differences. Wound of the tail end was observed in one pup of the 25 mg/kg group. Abnormal signs were not noted in the clinical observation in other animals. No abnormalities were noted in number of pups born, birth index, viability index on day 0, sex ration and external anomaly index in all groups.

Mortality / viability:

no mortality observed

Description (incidence and severity):

No abnormalities were noted in number of pups born, birth index, viability index on day 0.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No abnormal body weights were noted in males and females on day 0. Decreases in body weights were significantly noted in females of the 25 mg/kg group on day 4.

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

no effects observed

Description (incidence and severity):

No abnormalities were noted in sex ration

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not specified

Histopathological findings:

not specified

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Detailed results of the OECD 422 study are attached to the robust study summary for the endpoint “repeated dose toxicity: oral”

Poor nursing was observed in one animal of the vehicle control group including nursing loss and undevelopment of the nipples, and all her pups died on day 2 of the nursing period. One offspring was delivered and killed by the dam in the 150 mg/kg group just after delivery. Poor nursing including nursing loss and undevelopment of the nipples was observed in one animal of the 1000 mg/kg group during parturition, and all her pups were killed by the dam on day 1 of the nursing period. No abnormalities were observed in other animals.

Applicant's summary and conclusion

Conclusions:

The NOAEL of reproductive and developmental toxicity was 1000 mg/kg/day due to no toxicological signs in any dose groups.
The NOEL of reproductive and developmental toxicities was 1000 mg/kg/day due to no toxicological signs.