Registration Dossier

Administrative data

Key value for chemical safety assessment

Toxic effect type:
dose-dependent

Effects on fertility

Description of key information

The test item was investigated for its reproductive toxicity by administration to Crl:CD(SD) rats by oral gavage in compliance with OECD 421.

The no-observed-adverse-effect levels (NOAELs) of test item were determined to be 200 mg/kg/day in males and females for repeated dose toxicity; 600 mg/kg/day in males and 200 mg/kg in females for reproductive performance in parental animals, and 200 mg/kg for development and growth of the next generation.

Link to relevant study records
Reference
Endpoint:
screening for reproductive / developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2018-03-06 to 2018-06-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
Version / remarks:
July 29, 2016
Deviations:
no
GLP compliance:
yes
Limit test:
no
Specific details on test material used for the study:
Lot No.: C170806
Purity: 100%
Species:
rat
Strain:
other: CrI:CD(SD)
Details on species / strain selection:
Rats are generally used in toxicity studies and the test facility has abundant experience of using this strain of rats.
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories Japan, Inc.
- Age at study initiation: 11 weeks of age for both ma1es and females
- Weight at study initiation: 393 to 473 g for males, 236 to 292 g for females
- Housing:
- Type of cage: Metal bracket cages (300 W x 410 D x 200 H, mm) with wire mesh floors.
- Number of animals per cage: Two during quarantine and acclimatization period, 1 after group assignment, 1 male and 1 female during mating period, 1 female during gestation period, and 1 liter during lactation period
- Cleaning of the room: The animal room was cleaned once daily.
- Disinfection of the room: The room was disinfected once daily by wiping with chlorine or iodine disinfectants alternately on a weekly basis.
- Diet (e.g. ad libitum): free access to Pellet feed, CRF-1
- Water (e.g. ad libitum): Animals had unlimited supply of Sapporo-City tap water from the automatic watering system
- Acclimation period: From the day of receipt to the day of group assignment, including the quarantine period

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-23
- Humidity (%): 40-51
- Air changes (per hr): 10 to 15 times/hr
- Photoperiod (hrs dark / hrs light): 12 hrs (artificiallighting from 8:00 to 20:00)
Route of administration:
oral: gavage
Vehicle:
water
Remarks:
Japanese Pharmacopoeia purified water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
- Preparation method: For each dose level, a required amount of the test article was accurately weighed out and transferred to a graduated glass, to which the vehicle (control article) was added and stirred to dissolve the test article. To the solution, the vehicle was added to achieve the prescribed concentration, and stirred with a stirrer. For calculation of the amounts of the test article required to prepare the dosing solutions, correction for the purity of the test article was not conducted.
- Preparation frequency: At least every 12 days
- Expiration: Dosing solutions were used within the proved stability period (within 12 days).
- Storage conditions: Stored in an airtight and light-resistant container in a cold place (acceptable range, 1°C to 10°C; actual range 5.8°C to 6.9°C)

VEHICLE
- Concentration in vehicle: 6, 20, 60 mg/mL
- Amount of vehicle (if gavage): 10.0 mL/kg
- Lot/batch no. (if required): C07300
Details on mating procedure:
A male and a female in the same group were paired- M/F ratio per cage: 1:1
- Length of cohabitation: from the evening of the first day of mating until confirmation of copulation.
- Proof of pregnancy: vaginal plugs in the vagina or fallen on the cage trays, or sperm in vaginal smears referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged individually. And small trays with bedding for experimental animals (White flake; Charles River Laboratories Japan, Inc.) were used from gestation day 17 to lactation day 13.
- Any other deviations from standard protocol: no
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Dosing solutions of all concentrations were analyzed for concentrations of the test article at the first preparation and at the final preparation for males. The contents of the 6, 20, and 60 mg/mL dosing solutions prepared at the first and final preparation for males were 96.5% to 99.7% (relative standard deviations 0.1% to 4.8%), which were within the range of acceptance criteria (content, 100% ± 10.0%; relative standard deviation, 5.0% or less).
Duration of treatment / exposure:
Males: For 28 days from 14 days before the start of mating
Females: For 14 days before the start of mating and during mating period until successful copulation
Females with successful copulation: During gestation period and until lactation day 13
Females with no evidence of parturition: Until day 25 after successful copulation
Females that failed to mate: For 23 days from the day after the final day of mating period
Frequency of treatment:
Once daily on successive days
Details on study schedule:
- Age at mating of the mated animals in the study: 13 weeks
Dose / conc.:
60 mg/kg bw/day (actual dose received)
Remarks:
Low dose
Dose / conc.:
200 mg/kg bw/day (actual dose received)
Remarks:
Middle dose
Dose / conc.:
600 mg/kg bw/day (actual dose received)
Remarks:
High dose
No. of animals per sex per dose:
12 males and 12 females
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: In the 28-day repeated dose toxicity study, 750 mg/kg is a markedly toxic dose for both males and females; therefore, 600 mg/kg, which is expected to cause toxicity appropriate for evaluation of reproduction and developmental toxicity, was selected as the high dose level for the present study, and middle and low dose levels were set at 200 and 60 mg/kg with a common ratio of 3.
- Fasting period before blood sampling for clinical biochemistry: no data
Positive control:
Not performed
Parental animals: Observations and examinations:
CLINICAL OBSERVATIONS: Yes
- Time schedule: From administration day 1 to the day of necropsy, at least twice daily (pre and post administration, and once on the day of necropsy

BODY WEIGHT: Yes
- Time schedule for examinations:
Male: Before administration on administration days 1, 4, 7, 14, 21, and 28, and on the day of necropsy
Female: Before administration on administration days 1, 4, 7, and 14; before administration on gestation days 0, 7, 14, and 20; and before administration on lactation days 0, 4, 7, and 13; and on day 14 after parturition (day of necropsy). However, for females with no evidence of parturition, body weight on day 26 after successful copulation (day of necropsy) was recorded. For females that failed to mate, body weight before administration on administration days 21 , 28, 35, 42, and 49, and on the day of necropsy (the day after administration day 51) was recorded. For the animal that died (No. 50459), body weight at the time of finding death was recorded.

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/rat/day.
- Time schedule:
Male: On the same days as body weight measurement, except the weeks during mating and the day of necropsy
Female: Same as those for body weight measurement except cohabitation period and the day of necropsy

OTHER:
Measurement of serum T4 concentration:
- Time schedule: Blood was collected at necropsy
- Serum collection: Rats were anesthetized by isoflurane inhalation, and then blood was collected from the abdominal aorta into the test tube containing separator and centrifuged (ca. 2000 x g, 4℃, 10 min) to obtain serum.


Oestrous cyclicity (parental animals):
Period: From the first day of administration to the day of successful copulation; For female that failed to mate, until the final day of mating period
Method: Before necropsy on the day of necropsy, vaginal smears were collected from all females except the one that died and stained with Giemsa solution to determine the stage of estrous cycles under a light microscope
Litter observations:
STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in offspring:
Body weight, Anogenital distance, Nipple retention, serum T4 concentration

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; possible cause of death was determined for pups born or found dead.




Postmortem examinations (parental animals):
SACRIFICE
- Male animals: On the day after administration day 28
- Maternal animals: Day 14 after parturition However, one female that died was necropsied on gestation day 21. One female that failed to mate was necropsied 24 days after the end of mating period (the day after administration day 51). Four females with no evidence of parturition were necropsied on day 26 after successful copulation and one female with abnormal delivery was necropsied on lactation day 0.


GROSS NECROPSY
- Method: Animals were observed for external appearance and then euthanized by exsanguination and all organs and tissues were macroscopically observed. The organs and tissues described below were fixed and preserved in 10% neutral buffered formalin. The testes and epididymides were fixed in Bouin's solution and preserved in 70% ethanol. For fixing the testes, the tunica albugineae were punctured at both poles. For bilateral organs, both sides of them were fixed and preserved. Gross lesions were photographed before fixation. For bilateral organs, both sides of them were fixed and preserved. The number of implantation sites was counted.
- Organs and tissues:
Male animals: Thyroids, testes, epididymides, prostate, seminal vesicles (with coagulating glands), levator ani plus bulbocavemosus muscle complex, Cowper's gland, glans penis, and spleen
Maternal animals: The testes, epididymides, and organs and tissues in which abnormal findings were detected at necropsy. The testes were examined for spermatogenesis and the structure of testicular interstitial cells.


HISTOPATHOLOGY
- Number of animals:
Male: Microscopic specimens of testes or epididymides of all animals were prepared and those in the control and high dose groups were microscopically examined.
Female: Microscopic specimens of ovaries of all animals were prepared and those in the control and high dose groups were microscopically examined.
- Organs and tissues:
Male animals: The testes, epididymides, and organs and tissues in which abnormal findings were detected at necropsy
Maternal animals: Ovaries, and organs and tissues in which abnormal findings were detected at necropsy.

ORGAN WEIGHT
- Time schedule: At necropsy
- Organs: Male animals: Testes, epididymides, and seminal vesicles (with coagulating glands); Prostate

Postmortem examinations (offspring):
SACRIFICE
Animals were observed for external appearance (including the oral cavity), and those for blood collection were euthanized by decapitation, and the others were euthanized by excessive dose of pentobarbital sodium

GROSS NECROPSY
- Gross necropsy consisted of external examinations. All organs and tissues were macroscopically observed, too.

HISTOPATHOLOGY / ORGAN WEIGTHS
Microscopic specimens of the thyroid were prepared from all offspring of which thyroid was preserved, and those in the control and high dose groups were microscopically examined.
Statistics:
Statistical analyses were performed using the computer system (MiTOX). The test data were analyzed by the Bartlett test for homogeneity of variances, followed by the one way analysis of variance when group variances were homogeneous (p ≥ 0.05), or by the Kruskal-Wallis test when group variances were heterogeneous (p < 0.05). When a significant difference was detected (p < 0.1) by the one-way analysis of variance, Dunnett's test was performed for comparison with the control group. When a significant difference was detected (p < 0.1) by the Kruskal Wallis test, Steel's test was performed for comparison with the control group. Serum T4 concentration, and viability indices on postnatal days 0 and 13 were separately analyzed by the same statistical procedures as described above using a statistical analysis system (Sanken System Co, Ltd) or SAS system (SAS Institute Inc.).
Body weight of offspring and AGD were analyzed by a linear mixed model with litter as a random effect (SAS Institute Inc.). For body weight of offspring, litter size was used as a covariate, and on postnatal day 0, gestation period was also used as a covariate. The number of nipples of offspring was analyzed by a generalized linear mixed model with liter as a random effect (SAS Institute Inc.). For body weight, AGD and the number of nipples of offspring, Dunnett’s test was used for comparison to the control group.
The incidence of abnormal estrous cycles, copulation index, fertility index, gestation index, sex rate of live offspring, and incidence of dams with offspring showing external anomalies, and the results of histopathology were analyzed by Fisher's exact probability test. Histopathology of offspring was separately analyzed by the same statistical procedures as described above using SAS system (SAS Institute Inc.). For the comparative analysis with the control group, statistical significance level was set at 5%.
Reproductive indices:
Copulation index; Fertility index
Offspring viability indices:
Viability index(%) on postnatal day 0, 4 and 13
Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
In the 600 mg/kg group, 1 female showed soil of perioral/perinasal fur, tachypnea, and prone position after administration on gestation day 21, and died within the day (intrauterine condition: implantations, 16; live fetuses, 15; implantation site, 1). This animal was considered to have not started parturition because it showed no signs of parturition. In addition, reddish urine was noted in 1 female on administration days 13 to 15 and soil of perigenital fur in another female on gestation days 15 to 17. In the 60 or 200 mg/kg group, no abnormalities were noted in any males or females.
Mortality:
mortality observed, treatment-related
Description (incidence):
In the 600 mg/kg group, 1 female died on gestation day 21
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
In the 600 mg/kg group, body weight was low after the start of administration in both males and females, with significant differences in males from administration days 4 to 28, and in females on administration day 14, during the gestation and lactation periods, and on day 14 after parturition compared with those in the control group. In this group, body weight gain was also significantly low in males during the administration period and in females during the pre-mating and gestation periods. In males, body weight on administration day 28 and body weight gain during the administration period were 86 4% and 21.6%, respectively, relative to those in the control group. In females, body weight during the gestation and lactation periods was 83.6% to 91.8% and 82.3% to 85.9%, respectively, and body weight gain during the gestation and lactation periods was 70.6% and 80.0%, respectively, both relative to those in the control group. In addition, body weight gain of females in this group during the pre-mating administration period was -4.7 g. Thus, marked suppression of body weight increase was noted in both males and females. In the 60 or 200 mg/kg group, no significant differences were noted in body weight or body weight gain in males or females.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
In the 600 mg/kg group, food consumption was significantly low throughout the administration period in both males and females compared with that in the control group. In the 200 mg/kg group, food consumption was significantly low in males on administration days 4 and 7. This was considered toxicologically insignificant because no changes were detected in body weight. In the 60 mg/kg group, there were no significant differences in males or females.
Haematological findings:
no effects observed
Description (incidence and severity):
- Serum T4 concentration:
No significant differences were noted in either males or females in any dose group compared with the control group.
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
No abnormalities were noted in the testis, epididymnis, or ovary of any animal in the 600 mg/kg group. In the organs with gross lesions of animals in this group, histopathological examination revealed slight increase in extramedullary hematopoiesis of erythroblastic cells in the spleen of 2 males and 1 non-pregnant female. In addition, moderate ulcer was noted in the duodenum of the female that died. Besides, slight septum was noted in the vagina of 1 non-pregnant female. This is a congenital anomaly and was considered unrelated to the test article administration.
Reproductive function: oestrous cycle:
no effects observed
Description (incidence and severity):
No significant differences were noted in the incidence of abnormal estrous cycles, length of estrous cycle, or number of estrus between any dose group and the control gτoup.
Reproductive performance:
effects observed, non-treatment-related
Description (incidence and severity):
In the 600 mg/kg group, there were no significant differences in the copulation index or the number of days required for copulation compared with those in the control group, which indicated that there was no direct effect on the coitus ability. In this group, a pair failed to mate, which was considered due to deteriorated systemic condition because the pair showed marked decrease in body weight and the female of the pair showed reddish urine during 3 days from the day before start of mating. Among the females with successful copulation, 3 females were non-pregnant (1 of them showed congenital atresia of the vagina) and the fertility index tended to be low with no significant differences. In the 200 mg/kg group, 1 female with successful copulation was non-pregnant. This was considered unrelated to the test article administration because there was no significant difference in the fertility index, and there were no changes in the number of implantations in this group. In the 60 mg/kg group, there were no significant differences in any parameter.
Key result
Dose descriptor:
NOAEL
Effect level:
200 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
body weight and weight gain
food consumption and compound intake
gross pathology
histopathology: non-neoplastic
Key result
Dose descriptor:
NOAEL
Effect level:
600 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male
Basis for effect level:
reproductive performance
Key result
Dose descriptor:
NOAEL
Effect level:
200 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
female
Basis for effect level:
reproductive performance
Key result
Critical effects observed:
yes
Lowest effective dose / conc.:
600 mg/kg bw/day (actual dose received)
System:
haematopoietic
Organ:
spleen
Treatment related:
yes
Dose response relationship:
not specified
Relevant for humans:
not specified
Clinical signs:
no effects observed
Mortality / viability:
mortality observed, treatment-related
Description (incidence and severity):
In the viability index, a significantly low value was noted on postnatal day 0 in the 600 mg/kg group compared with that in the control group. On postnatal day 4 or 13, no changes were noted. In the 60 or 200 mg/kg group, no significant differences were noted.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
In the 600 m/kg group, body weight was significantly low in males from postnatal days 0 to 13 and in females on postnatal days 0 and 13, compared with that in the control group. Among these values, the estimated least-squares means on postnatal days 0 (covariates: gestation period and litter size) and 4 (covariates: litter size) of males and females were markedly lower than the measured values. In the 60 or 200 mg/kg group, no significant differences were noted in males or females.
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
In the 600 mg/kg group, serum samples were obtained from only 1 litter on postnatal day 4, and the T4 concentrations were within the range of the control group. The concentration on postnatal day 13 was significantly high compared with that in the control group. In the 200 mg/kg group, there was no signifcant difference on postnatal day 4, and the concentration was significantly high on postnatal day 13. In the 60 mg/kg group, there were no significant differences on postnatal day4 or 13.
Anogenital distance (AGD):
effects observed, treatment-related
Description (incidence and severity):
In the 600 mg/kg group, there were significant differences in AGD and AGD per cube root of body weight ratio in males compared with those in the control group. These were high values and not indicative of feminization; therefore, they were considered toxicologically insignificant. In the 60 and 200 mg/kg groups, there were no significant differences in males or females.
Nipple retention in male pups:
no effects observed
Description (incidence and severity):
No nipples were noted in any male offspring.
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
In the 600 mg/kg group, dilatation of the renal pelvis was noted in 1 dead offspring. This was considered unrelated to the test article administration because this is a change that occurs spontaneously in this strain of rats and occurred in only 1 animal. In the 200 mg/kg group, no abnormalities were observed other than narrowed tail corresponding to the external anomaly in 1 offspring. In the 60 mg/kg group, no abnormalties were noted in any offspring.
Histopathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
Histopathological examination of the thyroid revealed slight ultimobranchial body remnant in 2 females in the 600 mg/kg group. This change was noted also in the 5 females of the control group and there was no increase in its frequency; therefore, this change was considered unrelated to the test article administration. Other than this, no abnormal findings were noted in any males or females.
Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
200 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
viability
body weight and weight gain
Critical effects observed:
no
Reproductive effects observed:
yes
Lowest effective dose / conc.:
600 mg/kg bw/day (actual dose received)
Treatment related:
yes
Relation to other toxic effects:
reproductive effects as a secondary non-specific consequence of other toxic effects
Dose response relationship:
yes
Relevant for humans:
no

- Parturition and nursing hehavior:

In the 600 mg/kg group, no changes were noted in the gestation index; however, there was 1 female in which the time from the start to the end of parturition was 24 hours or more, and all offspring of this animal were born dead (stillbirth). In another female, the time from the start to the end of parturition was more than 4 hours. In the group means, the gestation period was significantly prolonged, and the numbers of implantations, offspring, live newborns (males and females separately and combined), and the birth index were significantly low, and the number of dead newborns was significantly high compared with those in the control group. In the 60 or 200 mg/kg group, no abnormalities were noted in parturition, and significant difference was not noted in any parameter. In external examination of offspring, no abnormalities were noted in the 60 or 600 mg/kg group. In the 200 mg/kg group, narrowed tail was noted in 1 offspring, which was considered unrelated to the test article administration because its frequency was low and this change was not observed in the 600 mg/kg group.

Conclusions:
The no-observed-adverse-effect levels (NOAELs) of test item were determined to be 200 mg/kg/day in males and females for repeated dose toxicity; 600 mg/kg/day in males and 200 mg/kg in females for reproductive performance in parental animals, and 200 mg/kg for development and growth of the next generation, under the present study conditions.
Executive summary:

The test item was investigated for its reproductive toxicity including effects on gonadal function, mating behavior, conception, and delivery by administration to 12 male and 12 female Crl:CD(SD) rats per group by oral gavage at 0 (control), 60, 200, and 600 mg/kg/day; to males for 28 days including pre-mating, mating, and post-mating periods; and to females during pre-mating, mating and gestation periods, and until day 13 afier parturition (for 40 to 56 days) in compliance with OECD 421.

Parental animals: In the 600 mg/kg group, 1 female showed soil of perioral/perinasal fur, tachypnea, and prone position on gestation day 21. This animal died within the day. Other than the above, reddish urine was noted in 1 female from administration days 13 to 15, and soil of perigenital fur in another female from gestation days 15 to 17. Body weight and food consumption were low throughout the administration period in both males and females. Necropsy revealed swelling of the spleen in males and females, and dark red focus in the duodenum in the female that died. Histopathologically, the former corresponded to an increase in extramedullary hematopoiesis of erythrocytic cells, and the latter corresponded to ulcer of the duodenum. No changes related to the test article administration were noted in the serum T4 concentrations, organ weight, or gonad histopathology. In the 200 and 60 mg/kg groups, no toxicologically significant changes were noted in any parameters.

Reproduction of parental animals and development of offspring: In the 600 mg/kg group there were lower tendency of fertility index and low number of implantations related to low food consumption, prolongation of the gestation period including prolonged duration of parturition, low numbers of offspring delivered and live newborns and birth index, and high number of dead newborns, though no significant difference was noted in gestation index. In particular, 1 female showed markedly prolonged duration of parturition and stillbirth (all offspring were dead). There were no significant differences in estrous cycle or coitus ability. In offspring of this group, the viability index on postnatal day 0 and the body weight of males and females were significantly low. No abnormalities related to the test article administration were noted in clinical observation, external examination or necropsy, and no toxicologically significant changes were noted in the number of nipples, anogenital distance, serum T4 concentration, or histopathological examination of the thyroid. In the 200 and 60 mg/kg groups, no changes of toxicological significance were noted in any parameter.

On the basis of the above results, the no-observed-adverse-effect levels (NOAELs) of test item were determined to be 200 mg/kg/day in males and females for repeated dose toxicity; 600 mg/kg/day in males and 200 mg/kg in females for reproductive performance in parental animals, and 200 mg/kg for development and growth of the next generation, under the present study conditions.

Effect on fertility: via oral route
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
200 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
1 (reliable without restriction)
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available

Justification for classification or non-classification

Screening for reproductive / developmental toxicity, OECD 421:

Parental animals:

In the 600 mg/kg group, 1 female showed soil of perioral/perinasal fur, tachypnea, and prone position on gestation day 21. This animal died within the day.

Other than the above, reddish urine was noted in 1 female from administration days 13 to 15, and soil of perigenital fur in another female from gestation days 15 to 17. Body weight and food consumption were low throughout the administration period in both males and females. Necropsy revealed swelling of the spleen in males and females, and dark red focus in the duodenum in the female that died. Histopathologically, the former corresponded to an increase in extramedullary hematopoiesis of erythrocytic cells, and the latter corresponded to ulcer of the duodenum.

No changes related to the test article administration were noted in the serum T4 concentrations, organ weight, or gonad histopathology. In the 200 and 60 mg/kg groups, no toxicologically significant changes were noted in any parameters.

 

Reproduction of males and females and development of offspring

In the 600 mg/kg group, there were lower tendency of fertility index and low number of implantations related to low food consumption, prolongation of the gestation period including prolonged duration of parturition, low numbers of offspring delivered and live newborns and birth index, and high number of dead newborns, though no significant difference was noted in gestation index. In particular, 1 female showed markedly prolonged duration of parturition and stillbirth (all offspring were dead).

In offspring of this group, the viability index on postnatal day 0 and the body weight of males and females were significantly low. As on postnatal days 4 and 13, no changes were observed and there were no abnormalities also in clinical observation, these indicated a possibility that the low viability index of offspring was attributed to prolonged duration of parturition or gestation. The estimated least - squares means were low, hence these results indicated that body weight appeared to be normally increased owing to prolonged gestation period and small litter sized before standardization. However growth was suppressed. No abnormalities related to the test article administration were noted in clinical observation, external examination or necropsy, and no toxicologically significant changes were noted in the number of nipples, anogenital distance, serum T4 concentration, or histopathological examination of the thyroid.

In the 200 and 60 mg/kg groups, no changes of toxicological significance were noted in any parameter.

Based on the above results it can be concluded that the test item should be classified as category 2 for reproductive or developmental effects according to regulation (EC) No 1272/2008 Table 3.7.1.

Additional information