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

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13th August 2018 to 24th November 2018

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Repeated Dose 28 Day Oral Toxicity study in Rodents (No. 407, adopted 2008), Ministry of Environmental Protection of the People's Republic of China

GLP compliance:

yes

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

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
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: 40-53 days
- Weight at study initiation: 206 -222g Males and 158-176g for Females
- Fasting period before study: not specified
- Housing: raised in suspended, stainless steel cages (L32.0 cm xW28.0 cmxH20.0 cm) on cage racks (L 167.0 cmxW70.0 cmxH171.0 cm).
- Diet (e.g. ad libitum): Yes (not for 24 hours prior to euthanasia)
- Water (e.g. ad libitum): yes
- Acclimation period: 5 days

DETAILS OF FOOD AND WATER QUALITY: sterilized diet with complete nutrition supplied by Beijing Keaoxieli Feed Co., LTD . All the nutrition components and contaminants were within the permitted limits described in the national standard. Water was purified by HT-R01000 purity system. Water analysis was conducted routinely analyzed (annually), and all parameters were within the permitted limits described

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-25
- Humidity (%): 40-70
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 2018-08-16 To: 2018-09-19

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

To determine the dose levels for the formal test, preliminary studies were conducted with 2 different groups of 3 male and 3 female per group at dose of 500 mg/kg and 600 mg/kg for a period of 10 days as a preliminary study. The results showed that on the first day, 3 animals in each group died, while the rest of the animals showed no abnormal symptoms. While another study 1 animal died on day 2 following exposure at 400mg/kg. Based on these results and according to the guidelines the doses of 0, 40, 120 and 360 mg/kg.bw/day were selected for the full study.

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Control - Corn oil

Doses / concentrations 2

Dose / conc.:

40 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

120 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

360 mg/kg bw/day (nominal)

No. of animals per sex per dose:

6 males/females for 40 and 120 mg/kg/day and 12 males/females for control and 360mg/kg/day groups (6 males and females for control and high dose group held for 21 days post exposure to measure reversibility of effects)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on the preliminary studies
- Rationale for animal assignment: Randomly grouped
- Fasting period before blood sampling for clinical biochemistry: 24 hour fasting overnight prior to necropsy, but water was available.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily 1 hour post dosing, mortality checks were made twice daily
- Cage side observations checked in table: Yes

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Prior to first exposure and once weekly after dosing. Observations included changes to fur, skin, eyes, mucous membranes, occurrence of secretions/excretions and autonomic activities, changes in gait, posture, and clonic and tonic movements

BODY WEIGHT: Yes
- Time schedule for examinations: weighed 24 hours after arrival, day prior to study start and once weekly during study

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes

OPHTHALMOSCOPIC EXAMINATION: NO

HAEMATOLOGY: Yes
- Time schedule for collection of blood:
- Anaesthetic used for blood collection: Not specified
- Animals fasted: Yes overnight prior to collection
- How many animals:
- Parameters checked in table [No.?] were examined.

CLINICAL CHEMISTRY: Yes / No / Not specified
- Time schedule for collection of blood:
- Animals fasted: Yes / No / Not specified
- How many animals:
- Parameters checked in table [No.?] were examined.

URINALYSIS: Yes / No / Not specified
- Time schedule for collection of urine:
- Metabolism cages used for collection of urine: Yes / No / Not specified
- Animals fasted: Yes / No / Not specified
- Parameters checked in table [No.?] were examined.

NEUROBEHAVIOURAL EXAMINATION: Yes / No / Not specified
- Time schedule for examinations:
- Dose groups that were examined:
- Battery of functions tested: sensory activity / grip strength / motor activity / other:

IMMUNOLOGY: Yes / No / Not specified
- Time schedule for examinations:
- How many animals:
- Dose groups that were examined:
- Parameters checked in table [No.?] were examined.

OTHER:

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

No changes of toxicological significance were observed in the result of clinical signs. The results of clinical observations showed that no abnormal symptoms
were observed in all animals throughout the course of the test.

Mortality:

no mortality observed

Description (incidence):

No changes of toxicological significance were observed in the result of mortality. The mortality results showed that no deaths were found during the whole test period.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No changes of toxicological significance were observed in the result of body weight. The results of body weight weighing showed that the body weight gains of all treatment groups were not inhibited by the test item. No significant differences were found in the average body weights and body weight gains of treatment groups as compared with those in the control groups.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No changes of toxicological significance were observed in the result of food consumption. The results of food consumption measurements showed that the food consumptions of all treatment groups were not inhibited by the test item. Compared with that in the control group, the average food consumption of male rats in the test item low-dose group transiently decreased (p<:::::0.05) in 1st week which was considered to be unrelated to the test item. Compared with those in the control group, the average food consumption of male rats in the test item high-dose groups all significantly increased from 2nd to 5th weeks (p<:::::Q.05, p<:::::0.01, p<:::::0.001 ), and the average food consumption of female rats in the test item high-dose group significantly increased (p<:::::0.01) in 2nd week. These changes were of no toxicological significances. Compared with the control group, no statistical differences were observed in the results of food consumption in the rest treatment groups.

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No changes related to the test item were found in the results of blood coagulation. The results of blood coagulation examination showed that compared with those in the control group, the APTT levels of male rats in test item middle-dose and high-dose groups significantly decreased (p<:::::0.05) at the end of exposure period. The results of hematology examination showed that compared with those in the control group, at the end of exposure period, the RBC and HGB levels of the male rats in the test item middle-dose and high-dose groups significantly decreased (p<=0.05, p<=0.001), and the HCT level of male
rats in the test item high-dose group significantly decreased (p<=0.01); at the ends of exposure and recovery periods, the RDW-SD levels of the male
rats in test item high-dose group significantly increased (p<=0.05); at the end of recovery period, the ROW-SD level of the female rats in test item high-dose group significantly increased (p<=0.05). The results of serum biochemistry examinations showed that compared with those in the control
group, the ALP and AST levels of female rats of test item high-dose group significantly increased (p<=0.01). Some of the changes with toxicological
significances described above showed a relative consistent trend between the treatment groups at some time period; some of them had relative large
amplitude of variation; some of them were seen both in male and female rats, which made it seemed to be influenced by the test item. However, as
for any change showed above, no evidently consistent changes were seen in other corresponding parameters of the same group in clinical
examinations at the same time period.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No changes related to the test item were found in the results of serum biochemistry. The results of serum biochemistry examination at the end of the exposure period showed that compared with those in the control group, the TP, ALB and CREA levels of male rats in test item high-dose group significantly decreased (p<=0.05, p<=0.01); the CREA level of female rats in test item middle-dose group significantly increased (p<=0.01) and the CHO level of this group significantly decreased (p<=0.05). Some of the changes above were of no toxicological significances; or some of them showed no consistent trends between the treatment groups at the same time period; or some of them showed opposite trends between male and female rats; or some of them were just of small variation amplitudes. Hence, these changes were considered to be accidental and transient, and unrelated to the test item.

Urinalysis findings:

no effects observed

Description (incidence and severity):

No changes related to the test item were found in the results of urinalysis. The results of urinalysis showed that compared with those in the control groups, no changes of toxicological significances were observed in the animals of the treatment groups.

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

No changes related to the test item were found in the results of organ weight. At the end of exposure period, as compared with those in the control groups, the organ weight of brain of male rats in test item middle-dose group significantly decreased (p<=0.05). At the end of recovery period, as compared with those in the control group, the organ weight and organ-to-body weight ratio of lung of male rats in test item high-dose group significantly increased (p<=0.05). All the changes showed above had no consistent trends between treatment groups at the same period, while some of the trends
were opposite between treatment groups, or some of them were of small amplitudes of variation, therefore, they were considered unrelated to the test item.

Gross pathological findings:

not specified

Neuropathological findings:

no effects observed

Description (incidence and severity):

No changes related to the test item were found in the results of nerve function. The results of nerve funtion examinations showed that compared with those in the control groups, no changes of toxicological significances were observed in the animals of the treatment groups.

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

No changes related to the test item were found in the results of histopathology. Histopathological lesions occurred at the end of exposure period in both female and male rats of the control and test item high-dose groups included liver vacuolation, urinary bladder dilation, epididymis spermatic granuloma, testicular atrophy, prostate gland inflammatory cell infiltrate, pituitary cyst, kidney cyst and uterus luminal dilation, etc, and the differences were of no statistical significances (p>0.05). Histopathological lesions occurred at the end of recovery period in both female and male rats of the control and test item high-dose groups included liver vacuolation, kidney cyst and uterus luminal dilation, etc, and the differences were also of no statistical significances (p>0.05). Most of the lesions mentioned above with a low incidence and mild degree which occurred both in the female and male rats at the ends of exposure and recovery period; some of them were only observed in the control groups;
some of them were occasionally seen in the test item high-dose groups, and as compared with the control group, there were no significant dose-response effects. Therefore, the histopathological findings observed were considered to be spontaneous lesions of SD rats, and unrelated to the test item.

Histopathological findings: neoplastic:

not specified

Other effects:

no effects observed

Description (incidence and severity):

No changes related to the test item were found in the results of necropsy. The necropsy result of all animals with
scheduled autopsy showed no abnormalities at the ends of both exposure and recovery periods.

Effect levels

Key result

Dose descriptor:

LOAEL

Effect level:

360 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

haematology

histopathology: non-neoplastic

mortality

organ weights and organ / body weight ratios

urinalysis

Target system / organ toxicity

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

The lowest-observed-adverse-effect-level (LOAEL) for the test material in the repeated dose 28-day oral toxicity study in SD rats under the conditions of this study was considered to be 360 mg/kg•bw/day for both males and females.