Boronic acid, B-(2-fluoro-3-methoxyphenyl)-

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OTS 798.4420 (Preliminary Developmental Toxicity Screen)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(2-fluoro-3-methoxyphenyl)boronic acid

EC Number:

609-099-0

Cas Number:

352303-67-4

Molecular formula:

FC6H3(OCH3)B(OH)2

IUPAC Name:

(2-fluoro-3-methoxyphenyl)boronic acid

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

CAS No.: 352303-67-4
Physical status: Off-white powder
Purity: 100.2%
Batch No.: 18051400
Expiry date: March 14, 2019

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Beijing Vital River Laboratory animal technology Co., Ltd. with Test Animals Quality Certification in Beijing of SCXK (Jing) 2016-0006 and the certificate number of 11400700318207.
- Females (if applicable) nulliparous and non-pregnant: Yes
- Animals were 56-62 days old on arrival
- Weight at study initiation: (P) Males: 280-330g Females: 190-230g
- Fasting period before study: not specified
- Housing: Suspension steel cages on cage racks, 2 rats per cage, during mating animal were housed in mating cages and after mating female rats were housed in plastic cages with cob bedding and prior to parturition females were housed on wood shavings
- Diet (e.g. ad libitum): During the test, all animals were provided with an unlimited supply of feed and water
- Water (e.g. ad libitum): yes
- Acclimation period: not
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-25
- Humidity (%): 40-70
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

All animals were administered once daily in the morning and seven times per week. The dosing volume of each animal was adjusted based on the latest body weight.
Administration period: Animals were dosed always until the day before dissection.
During childbirth, pregnant rats could not be dosed.

Details on mating procedure:

Animals were mated after administration for two weeks. During the mating period, female rats and male rats were put together as one to one ratio for two weeks. At the beginning, female and male rats were put into mating cages and inspected in the next morning. Then the female rats were examined for presence of the vaginal plug using vaginal smear method. The day of finding the sperm or vaginal plug was defined as day O of pregnancy (GDO).

Analytical verification of doses or concentrations:

no

Remarks:

There were no concentration, stability and homogeneity analysis in this study. So the test item was prepared daily during dosing period and mixed adequately before using

Duration of treatment / exposure:

All animals were dosed during two weeks prior to mating, two weeks of the mating period, and up to the day before scheduled kill.

Frequency of treatment:

daily seven times per week

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

400 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

160 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

60 mg/kg bw/day (nominal)

No. of animals per sex per dose:

4 male/ 4 female

Control animals:

yes, concurrent vehicle

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
During the administration, a cage-side observation was made at least once a day and could be along with administration; a detailed observation with handling was made once per week and it could be in company with the animal weighing. All animals were observed for morbidity and mortality twice daily (once daily on non working day).

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily and once per week
a) Cage-side observation: observe the appearance, fur, activity, reaction, breathing, posture, excrement and urine.
b) Observation with handling: take out the animal from the cage and put on a table, observe any abnormality of neck, head (including eyes, ears, mouth and nose), back, abdomen, anus, skin color around perineum, muscle tension, any trauma and tumour.

BODY WEIGHT: Yes
Time schedule for examinations: All animals were weighed at grouping, and once per week during the premating and mating period; all pregnant rats were weighed on day 0, 7, 14, 20 during the gestation period; parental rats and pups were weighed on PNDO and PND4 of lactation. Then mother rats were weighed once per week to adjust administration. All animals were weighed on the day of scheduled kill.

Other:
All pregnant rats were observed for parturition from GD21 twice daily in the morning and afternoon respectively (once daily on non working day). Any difficulties and abnormalities occurring during parturition were recorded on that parturition is observed to finish was considered as postnatal day (PNDO).

Postmortem examinations (parental animals):

During the study, a necropsy were performed on animal of death inter currently or morbidity and mortality, males after the end of the mating period; all mother rats and non-mated females after the day on PND4 of the last parturition pups. Animals were euthanized by C02 inhalation followed by examinations from abdominal aorta and subjected to a full necropsy and general observation. The necropsy included carefully examinations of the external features of the carcass, external body orifices, the abdominal, thoracic, and cranial cavities and their contents of all animals, and the location, size, hardness and the color of the abnormal findings were recorded. Special attention was paid to the organs of the reproductive system. For the parous females, the number of implantation sites in the uteri was recorded.
Weigh testicle and epididymis of both sides.

Offspring viability indices:

On PNDO, the number of live births, stillbirths, grossly malformed pups and grossly puniness pups were recorded and evaluated. Observe pups whether signs and behavior disorders or not until PND4. Record the number of live births and malformed pups on PND4.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

During the study, in low-dose group one male had tumor and one male had dehairing and scab, two females in control and low-dose group separately had emaciation and soiled perinea region.

Mortality:

not specified

Description (incidence):

0, 2, 1 and 1 males in control and low-, mid- and high-dose groups were found accidental death, 2, 0, 2 and 2 females were found accidental death. The symptom incidence rate and animal death rate had no statistically significant increase compared with the control group (p>0.05) and no dose correlation, the death and abnormality was not considered dependent of the test item toxicity.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

During premating and mating period, the mean body weight and the body weight gain of males in all dose groups had no significantly difference compared with the solvent control group (p>0.05). During premating period, no significantly difference of females for mean body weight and body weight gain were observed in all dose groups compared with the solvent control group (p>0.05). During gestation period, the body weight of pregnant rats in high-dose group during pregnant period (GD7, GD14) had a statistically significant increase compared with the control group (p>0.05), but no toxicology significance. During lactation period , there was no significantly difference of mother rats' body weight and body weight gain in all dose groups compared with the solvent control group (p>0.05).

Food efficiency:

effects observed, non-treatment-related

Description (incidence and severity):

During the premating period, the mean food consumption and total food consumption of males in all dose groups had no significantly difference compared with the solvent control group (p>0.05). During the premating period, the mean food consumption and total food consumption of females in high-dose group had a statistically significant increase compared with the control group (p>0.05 or p> 0.01), no significantly difference was found in low- and mid-dose groups(p>0.05); The food consumption of pregnant rats on GD14 in high-dose group had a statistically significant increase compared with the control group (> 0.01), no significantly difference was found in low- and mid-dose groups(p>0.05). There was no significantly difference on the food consumption of the dams during the lactation period in all dose groups compared with the solvent control group (p>0.05). According to the results above, the test item may activate the increase of food consumption, but males were not found similar effect, and no dose-dependent adverse effect was observed, so it was considered that the results had no correlation with the test item toxicity.

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

The animal of the control and high-dose groups were preserved and examined including males' testis and epididymis, females' ovaries, among all scheduled necropsy animals, one male in mid- and high-dose groups was observed with epididyrnis inflammatory cell infiltration respectively, one female in mid-dose group was observed with ovary cyst, one female in high-dose group was observed with ovary corpora lutea degeneration; But no statistics significance (p>0.05); No toxicity histopathological abnormity of all inspected animals was observed.

Reproductive function / performance (P0)

Reproductive function: sperm measures:

no effects observed

Description (incidence and severity):

Weigh testicle and epididymis of both sides about all male rats, and calculate relatively viscera weight based on the terminal weight; the relatively epididymis, the testicle and terminal bodyweight in all dose group had no significantly difference compared with the solvent control group (P>0.05).

Reproductive performance:

no effects observed

Description (incidence and severity):

Fourteen female rats and fourteen male rats (13 males in high-dose group) were put together as one to one ratio for mating in this study. There were 13, 14, 14 and 13 mated male rats in the solvent control groups and 60, 160, 400mg/kg/bw; there were 13, 14, 13 and 13 mated female rats which were found vaginal plug, and one female in the mid- and high-dose group each were not found accurate mated evidence but pregnant, so the successful mated females in the mid- and high-dose group were 14; and 13, 13, 12 and 14 pregnant female rats; 12, 11, 10 and 12 pregnant rats had live pups; and 1, 5, 3 and 1 pregnant rats respectively had at least one stillbirth pup, one pregnant rats in low-dose group had all pups being stillbirth; 1, 0, 1 and 2 pregnant rats died during pregnancy period which were observed fetus rats in uterus when necropsy; one dam died during lactation period in control and mid-dose groups respectively; There was no significantly difference of the results above in all dose groups compared with the solvent control group (p>0.05), so it was considered that the results had no correlation with the test item toxicity; no pregnant rats died for dystocia.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

2

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

Results: F1 generation

General toxicity (F1)

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

The live births index of pups in high-dose group had a statistically significant increase compared with the control group (p >0.05), the live births index of pups in low-dose group had a statistically significant decrease compared with the control group (p > 0.05), no significantly difference in mid-dose group was found(p>0.05), as a result of no dose correlation, so that was considered no toxicology significance.
The pup viability index in high-dose group had a statistically significant decrease compared with the control group (p > 0.01), which was considered attributing the death of all 20 pups in animal 2309, causing by individual litter data, no correlation with the test item administration, no significantly difference of pup viability index in low- and mid-dose group was found(p>0.05), The post-implantation loss in mid-dose group had a statistically significant decrease compared with the control group (p,s;0.05), but without toxicology significance, no significantly difference were observed of pups post-implantation loss in low- and high-dose group(p>0.05); The males ratio of low-dose group had a statistically significant increase compared with the control group (p ,s; 0.05), but no significantly difference were observed in mid- and high-dose groups, no dose correlation, so that was considered without correlation with the test item administration. There was no significantly difference in average implantation number, live births number, stillbirth number and live pups number on PND4 compared with the solvent control group (p>0.05).

Body weight and weight changes:

no effects observed

Description (incidence and severity):

There was no significantly difference in average litter weight in all dose groups compared with the solvent control group (P>0.05) in PNDO and PND4

Gross pathological findings:

no effects observed

Description (incidence and severity):

No malformation and significantly abnormality of all live pups in all groups were observed from birth to study ending (p>0.05).

Other effects:

no effects observed

Description (incidence and severity):

No malformation and significantly abnormality of all live pups in all groups were observed from birth to study ending (p>0.05).

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

400 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

not specified

Basis for effect level:

viability

body weight and weight gain

Overall reproductive toxicity

Key result

Reproductive effects observed:

no

Lowest effective dose / conc.:

400 mg/kg bw/day (nominal)

Treatment related:

no

Applicant's summary and conclusion

Conclusions:

For fertility and development, there was no adverse effect on the fertility of males and females  in 400mg/kg.bw group; there was no adverse effect  on the growth and development of pups, so it was considered FMPBA had no obvious fertility and development toxicity for rats at 400mg/kg.bw dose level.

Based on the results above, it is concluded that the No Observed Adverse Effect Level (NOAEL) for general toxicity to parent rats for exposure to FMPBA by oral is 400mg/kg.bw; The NOAEL for reproduction toxicity to parent rats for exposure to the test item by oral is 400mg/kg.bw, the NOAEL for developmental toxicity to pups for exposure to the test item by oral is 400mg/kg.bw.

Executive summary:

This study was conducted to provide initial information on possible effects  on reproduction/ developmental toxicity of FMPBA, following  exposure by oral in rats, also to be used as a dose range finding study for other reproduction/developmental studies. The method of this test was designed to be compatible with Guidelines for the Testing of Chemicals (the second edition), No.421:Reproduction/Developmental Toxicity Screening  Test, State Environmental Protection Administration (2013 ).

This study was conducted in SD rats and all animals were SPF grade. Based on the preliminary results of the preliminary test for the repeated dose oral toxicity,  three doses of 400,  160  and 60mg/kg.bw were used in the  study,  a concurrent solvent control was included. There were fourteen male and fourteen female rats in each  group.  All animals were dosed during two weeks prior to mating, two weeks of the mating period, and up to the day before scheduled kill. The test was finished after four days of the last litter pups birth. The clinical observations  were  made daily,  and body  weight and food  consumption were weighed weekly.  The reproductive/developmental parameters were evaluated at the  same time.  All parental  animals were macroscopically examined for  any abnormalities  and pathological  changes. The histopathology examination was made for the reproduction organs of rats in the control group and high-dose group. During  the  study,  no  test  item  administration correlative  abnormity symptom was found in all dose groups.  0, 2,  1   and 1   males in control and low-, mid- and high-dose  groups were found  accidental death,  2, 0,  2  and 2 females were found accidental death. But the animal death rate had no statistically significant increase compared with  the control group (p>0.05), the  death and abnormity was not considered dependent of the test item toxicity. 

During the study,  the body weight of males in all dose groups had no adverse effect;  during gestation period, the body weight of pregnant rats in high-dose group during pregnant period (GD7, GD14) had a statistically significant increase compared with the control group (p:s;0.05), but no toxicology significance. During the premating period, the food consumption of males in all dose groups had no significantly difference compared with the solvent control group, but the mean food consumption and total food consumption of females in high-dose group had a statistically significant increase compared with the control group (p:s;0.05  or p:S0.01), and the food consumption of pregnant rats on GD14 in high-dose group had a statistically significant increase compared with the control group (p:s;0.01), it was  considered the  test  item in  this  dose may activate the  increase of food consumption,  but males were not found similar effect,  and no dose-dependent adverse  effect  was  observed,  so  it  was  considered  that  the  results  had  no correlation with the test item toxicity. There were no significantly difference of males mating index, fertility index in all dose groups compared with the solvent control group (p>0.05); There were no significantly difference of females mating index, fertility index, fecundity index and gestation index in all dose groups compared with the solvent control group (p>0.05), and there were no significantly difference of females mating time and gestation  days  in  all  dose  groups  compared with  the  solvent  control  group (p>0.05).

The pup viability index in high-dose group had a statistically significant decrease compared  with  the  control  group  (p:s;0.01),  the  live  births  index  of pups  in low-dose group had a statistically significant decrease compared with the control group (p:s;0.05), but the results of above were considered attributed to the death of all pups in single litter in corresponding dose group, caused by individual difference,  no correlation  with the test item administration.  The males ratio of low-dose group had a statistically significant increase compared with the control group  (p:s;0.05),  but  no  significant  differences  were  observed  in  mid-  and high-dose groups, without dose correlation,  so that was considered without correlation with the test item administration. There was no significantly difference in average implantation number,  live births number,  stillbirth number and live pups number compared with the solvent control group (p>0.05).

The inspection of gross necropsy and histopathological examination was done to animals,  no  significantly  difference   of   gross  necropsy  and  histopathology examination were found to be related with the test item treatment. Exposure of rats to different doses of FMPBA by oral resulted that, no test item disposal correlated animal death and toxicity symptom was found in 60,  160, 400mg/kg.bw  dose groups, so it was considered the test item had no obvious general toxicity to parent rats at 400mg/kg.bw dose group.