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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
23 October 2015 -- 10 December 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Compliant to GLP and testing guidelines; adequate consistence between data, comments and conclusions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: colorless to yellowish liquid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: breeder: Janvier, le Genest-Saint-Isle, France
- Age/Weight: at the beginning of the treatment period, the animals were 10-11 weeks old and had a mean body weight of 297 g (range: 256 g to 356 g)
- Fasting period before study: no
- Housing: polycarbonate cages
- Diet: SSNIFF R/M-H pelleted diet (free access)
- Water: tap water filtered with a 0.22 µm filter (free access)
- Acclimation period: at least 4 days before the beginning of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): approximately 8 to 15 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h

IN-LIFE DATES: 16 November 2015 to 10 December 2015

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
Type of formulation
(visual observation):
- solution in the vehicle

Preparation procedure:
According to the analysis and stability study describing the preparation procedure (homogeneity and stability testing) for a range of concentrations covering the lowest and highest used in this study
Frequency and storage of preparations (control and test item dose formulations):
- based on test item dose formulation stability and vehicle expiry

Delivery conditions:
- at room temperature, protected from light

VEHICLE
- Justification for use and choice of vehicle: suitable formulation in corn oil
Used for preparation of test item dose formulations and administered to control group (control dose formulation).
Corn oil was already chosen as a vehicle in previous oral pharmacokinetic study following administration with the test item.

- Concentration in vehicle: 20, 60, and 200 mg/mL
- Amount of vehicle (if gavage): 5 mL/kg/day.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Type of method: GC-FID
Test item concentrations: remained within an acceptable range of variation compared to nominal values in Weeks 1 and 2.
Details on mating procedure:
- Proof of pregnancy: detection of a vaginal plug
Duration of treatment / exposure:
Day 6 to Day 20 post-coitum inclusive
Frequency of treatment:
Daily
Duration of test:
21 days
No. of animals per sex per dose:
24 females
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale:
The dose-levels were selected in agreement with the Sponsor, on the basis of the results of the following previous in which the test item, was administered daily by gavage to pregnant female rats from implantation to the day before scheduled hysterectomy (Day 6 to Day 20 post-coitum inclusive) at dose-levels of 100, 300 or 1000 mg/kg/day.
No mortality was observed. All females were pregnant, except three control animals and two females treated at 1000 mg/kg/day. All pregnant females had viable fetuses.
There were no effects on body weight, body weight change or food consumption at any dose-levels when compared to controls. There were no clinical signs, except ptyalism observed on a dose-related manner in all test item-treated groups.
At hysterectomy, no test item effects were noted on maternal or litter data.
Blood samples taken 6 hours after dosing on Day 20 p.c. for the determination of plasma levels of the test item demonstrated a dose-related internal exposure.
Therefore, 100, 300 and 1000 mg/kg/day were selected.

- Rationale for animal assignment: computerized stratification procedure

Examinations

Maternal examinations:
MORBIDITY AND MORTALITY:
- Time schedule: at least twice a day during the treatment period.

CLINICAL OBSERVATIONS:
- Time schedule: once a day during the treatment period.

BODY WEIGHT:
- Time schedule: on Days 2, 4, 6, 9, 12, 15, 18 and 21 p.c..

FOOD CONSUMPTION:
- Time schedule: on Days 2-4, 4-6, 6-9, 9-12, 12-15, 15-18 and 18-21 p.c..

POST-MORTEM MACROSCOPIC EXAMINATION:
- Sacrifice on Day 21 p.c..
- Examined: principal thoracic and abdominal organs and the weight of the gravid uterus.
Ovaries and uterine content:
The ovaries and uterine content were examined after termination, including::
- number of corpora lutea,
- number and distribution of dead and live fetuses,
- number and distribution of early and late resorptions,
- number and distribution of uterine scars,
- number and distribution of implantation sites.
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: half per litter
- Other : number dead and live, body weight, sex
Statistics:
Data were compared by one-way analysis of variance and Dunnett test (mean values being considered as normally distributed and variances being considered as homogeneous) or by Fisher exact probability test (proportions).

Indices:
% Pre-implantation loss = 100 * (Number of corpora lutea - Number of implantation sites) / Number of corpora lutea
% Post-implantation loss = 100 * (Number of implantation sites - Number of live fetuses) / Number of implantation sites

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Description (incidence and severity):
Details on maternal toxic effects:
Excessive salivation (recorded as ptyalism) was observed at 1000 mg/kg/day. Tremors were noted in one female treated at 1000 mg/kg/day on Days 17 and 18 p.c. These findings were considered to be non-adverse effects of the test item treatment.

Other clinical signs (such as reddish vaginal discharge, cutaneous lesions and chromorhinorrhea) were observed in some control and/or test item animals with absence of any dose-relationship.
Nodosity on mammary gland was also noted from Day 19 p.c. in one female treated at 1000 mg/kg/day. These findings observed in rats of this strain when housed in laboratory conditions, and were not attributed to the test item treatment.
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Body weight and body weight gain were not affected by the test item treatment when compared with control values.
At 1000 mg/kg/day, significantly higher mean body weight gain (+25 g vs. +20 g in controls, p<0.05) was recorded between Days 9 and 12 p.c. when compared with controls. This difference was mainly due to one isolated animal and thus considered to be of no toxicological importance.
Net body weight change (body weight change over the treatment period adjusted for the gravid uterus weight) was increased at 100 and 300 mg/kg/day when compared with controls, but no dose-relationship was observed.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
There were no test item effects on food consumption when compared to controls.
At 1000 mg/kg/day, significantly higher mean food consumption (25 g vs. 22 g in controls, p<0.01) was recorded between Days 9 and 12 p.c. when compared with controls. This difference was mainly due to one isolated animal and thus considered to be of no toxicological importance.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
A statistically significant increase was noted in mean relative liver (19.06 vs. 16.5 g, p<0.01) and kidney (2.30 vs. 2.11 g, p<0.01) weight values at 1000 mg/kg/day when compared with controls.
Mean gravid uterus weights and carcass weights of test item-treated animals were similar to control values.
Gross pathological findings:
no effects observed
Description (incidence and severity):
A mass on mammary gland was observed in one female at 1000 mg/kg/day and a scab on skin was noted in one female given 100 mg/kg/day. These macroscopic lesions were observed in isolated animals, without any dose relationship, and are commonly observed in rats of this strain when housed in laborator y conditions. They are thus considered not to be test item treatment-related.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Number of abortions:
no effects observed
Pre- and post-implantation loss:
no effects observed
Total litter losses by resorption:
no effects observed
Early or late resorptions:
no effects observed
Dead fetuses:
no effects observed
Changes in pregnancy duration:
no effects observed
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed
Changes in number of pregnant:
no effects observed
Other effects:
not specified

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Remarks on result:
not determinable due to absence of adverse toxic effects

Results (fetuses)

Fetal body weight changes:
no effects observed
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
no effects observed
Changes in litter size and weights:
no effects observed
Changes in postnatal survival:
not examined
External malformations:
no effects observed
Description (incidence and severity):
The few external malformations recorded without any dose-relationship in low- and mid-dose levels group s are common observations in this species and strain. There were no external malformations in fetuses from the high-dose group.
Skeletal malformations:
no effects observed
Description (incidence and severity):
There were no test item treatment-related cartilage abnormalities.
At 1000 mg/kg/day, 23/23 litters had fetuses with unossified or incomplete ossification of various part of the skeleton. These findings were associated with presence of cartilage and were considered to be test item treatment-related but not adverse.
There were no test-item treatment related skeletal malformation.
At 1000 mg/kg/day, on litter had a fetus, with knobby ribs. This malformation was associated with other thoracic skeletal variations (thickened and wavy ribs). Taking into account the absence of associated or similar findings in other groups and the isolated occurrence of this finding, a test item treatment-related effect was considered unlikely.
Visceral malformations:
no effects observed
Description (incidence and severity):
There were no test item treatment-related soft tissue malformations. The soft tissue malformations recorded without any dose relationship in control, low- and mid-dose-levels groups were observed in isolated fetuses. There were no soft tissue malformations in fetuses from the high-dose group.
Other effects:
effects observed, treatment-related
Description (incidence and severity):
The few external variations recorded in mid- and high-dose-levels groups are common observations in this species and strain. They are thus considered not to be test item treatment-related.
There were no test item treatment-related soft tissue variations.
The soft tissue variations recorded without any dose-relationship in control, low- and mid-dose-levels groups are common observations in this species and strain. There were no soft tissue variations in fetuses from the high-dose group.

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Remarks on result:
not determinable due to absence of adverse toxic effects

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Any other information on results incl. tables

Clinical signs observed in animals during the study are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

Tremors

0

0

0

1

Reddish vaginal discharge

6

3

4

1

Chromorhinorrhea

2

0

0

0

Ptyalism

0

0

0

6

Cutaneous lesion on neck ventral area

0

2

1

0

Nodosity on mammary gland

0

0

0

1

Number of affected animals

8/24

5/24

5/24

8/24

 

Mean body weights and mean body weight changes are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

 

Body weight (g)

 

 

 

 

 

Day 6p.c.

300

298

298

300

 

 Difference from controls (%)

 (-1)

(-1)

(0)

Day 21p.c.

448

443

446

445

 

Difference from controls (%)

 

(-1)

(0)

(-1)

 

Body weight change (g)

 

 

 

 

 

Days 9 - 12p.c.

+20

+19

+24

+25*

 

Difference from controls (%)

 

(-5)

(+20)

(+25)

 

Days 6 - 21p.c.

+147

+145

+149

+145

 

Difference from controls (%)

 

(-1)

(+1)

(-1)

 

*: p<0.05.

 

Mean food consumptions (g/animal) are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

. Days 6 - 9p.c.

19

19

19

18

. Days 9 - 12p.c.

22

22

23

25**

. Days 12 - 15p.c.

25

24

24

25

. Days 15 - 18p.c.

29

28

28

29

. Days 18 - 21p.c.

28

29

29

29

**: p<0.01.

 

Mean gravid uterus weights, net weight changes and carcass weights in pregnant females are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

Gravid uterus weight (g)

106.7

96.2

100.4

104.0

Difference from controls (%)

 

(-10)

(-6)

(-3)

Carcass weight (g)

340.9

347.0

345.9

341.3

Difference from controls (%)

 

(+2)

(+1)

(+0)

Net body weight change from Day 6p.c.(g)

40.6

49.1

48.3

41.2

Difference from controls (%)

 

(+21)

(+19)

(+1)

Liver and kidney weight values are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

Finalnetbody weight (g)

334.7

341.2

342.0

338.8

Liver:

         Mean weight

16.50

16.93

17.86

19.06**

         Mean % net body weight

4.90

4.94

5.21

5.62**

Kidneys:

         Mean weight

2.11

2.15

2.20

2.30**

         Mean % net body weight

0.64

0.63

0.64

0.68*

*: p<0.05, **: p<0.01.

 

Pregnancy parameters are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

Number of females with live fetuses at termination

21

21

22

23

Mean number ofcorpora luteaper animal

14.8

14.9

14.7

15.3

Mean number of implantations per animal

14.1

13.1

13.5

13.9

Mean pre-implantation loss (%)

4.1

10.8

8.5

8.1

Mean number of fetuses per animal

13.1

12.0

12.6

12.9

Dead fetuses (%)

0.0

0.0

0.0

0.0

Mean number of implantation scars

0.0

0.0

0.1

0.0

Mean number of early resorptions

1.0

0.9

0.8

0.8

Mean number of late resorptions

0.0

0.2

0.0

0.2

Mean post-implantation loss (%)

6.9

10.2

8.9

7.4

 

Mean fetal body weights and percentages of male fetuses (sex-ratio) are summarized in the following table:

 

Dose-level (mg/kg/day)

0

100

300

1000

Mean fetal body weight (g)

5.83

5.69

5.72

5.70

Difference from controls (%)

 

(-2)

(-2)

(-2)

Male fetuses (g)

5.98

5.85

5.85

5.84

Difference from controls (%)

 

(-2)

(-2)

(-2)

Female fetuses (g)

5.70

5.58

5.57

5.58

Difference from controls (%)

 

(-2)

(-2)

(-2)

 

Mean percentage of male fetuses (%)

 

49.7

44.4

46.7

47.5

Fetal and litter incidences of external variations are summarized in the following table:

 

Fetal (Litter) incidences (%) of external variations:

 

Dose-level (mg/kg/day)

0

100

300

1000

Number of litters

21

21

22

23

Number of fetuses

275

252

277

297

Litters affected, n (%)

0 (0)

0 (0)

1 (4.5)

2 (8.7)

Fetus affected, n (%)

0 (0)

0 (0)

3 (1.1)

2 (0.7)

Main findings

 

 

 

 

Local edema, F (L)

0 (0)

0 (0)

0 (0)

1 (1)

Protruding tongue, F (L)

0 (0)

0 (0)

3 (1.1)

2 (0.7)

 

Fetal and litter incidences of external malformations are summarized in the following table:

 

Fetal (Litter) incidences (%) of external malformations

 

Dose-level (mg/kg/day)

0

100

300

1000

Number of litters

21

21

22

23

Number of fetuses

275

252

277

297

Litters affected, n (%)

0 (0)

1 (4.8)

1 (4.5)

0 (0)

Fetus affected, n (%)

0 (0)

1 (0.4)

3 (1.1)

0 (0)

Main findings

 

 

 

 

Cleft palate, F (L)

0 (0)

0 (0)

3 (1)

0 (0)

Mandibular micrognathia, F (L)

0 (0)

0 (0)

3 (1)

0 (0)

Omphalocele, F (L)

0 (0)

1 (1)

0 (0)

0 (0)

F: fetal incidence, L: litter incidence.

 

Fetal and litter incidences of soft tissues variations are summarized in the following table:

 

Fetal (Litter) incidences (%) of soft tissue variations

 

Dose-level (mg/kg/day)

0

100

300

1000

Number of litters

21

21

21

23

Number of fetuses

132

121

131

144

Litters affected, n (%)

3 (14.3)

4 (19.0)

5 (23.8)

0 (0.0)

Fetus affected, n (%)

8 (6.1)

5 (4.1)

5 (3.8)

0 (0.0)

Main findings

 

 

 

 

Vessels: Short innominate artery, F (L)

3 (1)

3 (2)

2 (2)

0 (0)

Vessels: Absent innominate artery, F (L)

4 (2)

2 (2)

3 (3)

0 (0)

Dilated ureter, F (L)

1 (1)

0 (0)

0 (0)

0 (0)

F: fetal incidence, L: litter incidence.

Fetal and litter incidences of soft tissues variations are summarized in the following table:

 

Fetal (Litter) incidences (%) of soft tissue malformations

 

Dose-level (mg/kg/day)

0

100

300

1000

Number of litters

21

21

21

23

Number of fetuses

132

121

131

144

Litters affected, n (%)

1 (4.8)

1 (4.8)

1 (4.8)

0 (0.0)

Fetus affected, n (%)

1 (0.8)

1 (0.8)

1 (0.8)

0 (0.0)

Main findings

 

 

 

 

Absent kidney, F (L)

1 (1)

1 (1)

0 (0)

0 (0)

Vessels: absent aortic arch, F (L)

0 (0)

0 (0)

1 (1)

0 (0)

Absent ureter, F (L)

0 (0)

1 (1)

0 (0)

0 (0)

F: fetal incidence, L: litter incidence.

 

Dose-related fetal skeletal variations are summarized in the following table:

 

Fetal (Litter) incidences (%) of dose-related skeletal variations

 

Dose-level (mg/kg/day)

0

100

300

1000

HCD

Number of litters

21

21

22

23

182

Number of fetuses

143

131

146

153

1249

Hyoid : unossified

0 (0)

0 (0)

0 (0)

1.3 (8.7)

0 (0)

Thoracic vertebra: incomplete ossification of centrum

6.3 (28.6)

6.1 (38.1)

7.5 (31.8)

9.2 (39.1)

18.4 (57.1)

Lumbar vertebra: bipartite ossification of centrum

0 (0)

0 (0)

0 (0)

0.7 (4.3)

0 (0)

Caudal vertebra: unossified centrum

0 (0)

0 (0)

0.7 (4.5)

3.3 (8.7)

0.4 (2.7)

Caudal vertebra: incomplete ossification of arch

0 (0)

0 (0)

0 (0)

0.7 (4.3)

1.2 (6.0)

Extra stenebral ossification site

0 (0)

0 (0)

0 (0)

0.7 (4.3)

0.2 (1.6)

Wavy ribs

0 (0)

0 (0)

0 (0)

0.7 (4.3)

0.9 (5.5)

Thickened ribs

0 (0)

0 (0)

0 (0)

1.3 (4.3)

0.6 (3.3)

Unossified 1st metacarpals

0 (0)

0 (0)

0 (0)

0.7 (4.3)

0.2 (1.1)

Incomplete ossification of metacarpals

10.5 (28.6)

7.6 (28.6)

8.9 (31.8)

11.1 (30.4)

0.2 (1.6)

Forepaw: unossified proximal phalanx

49.7 (95.2)

41.2 (95.2)

56.2 (86.4)

68.0 (100.0)

5.3 (21.4)

F: fetal incidence, L: litter incidence.

HCD: Historical Control Data (Sprague-Dawley rat, Janvier Le Genest - France, March 2013 to June 2014).

In bold and underlined: higher fetal and/or litter incidencesvs.upper limits of the HCD and contemporaneous controls.

 

Applicant's summary and conclusion

Conclusions:
The test item, was daily administered as a solution in corn oil at dose-levels of 100, 300 or 1000 mg/kg/day, from Day 6 to Day 20 p.c., by oral route (gavage), to mated female Sprague-Dawley rats.
On the basis of the results obtained in this study:
- the No Observed Adverse Effect Level (NOAEL) for maternal parameters was considered to be 1000 mg/kg/day,
- the No Observed Adverse Effect Level (NOAEL) for embryo-fetal development was considered to be 1000 mg/kg/day.
Executive summary:

The potential toxic effects of the test item, diacetone alcohol, was evaluated on the pregnant female and on embryonic and fetal development, following daily oral administration (gavage) to pregnant female rats from implantation to the day before scheduled hysterectomy (Day 6 to Day 20 post-coitum (p.c.) inclusive). This GLP study was carried out according to OECD test guideline No. 414 (22 January 2001). The dose-levels were selected in agreement with the Sponsor, on the basis of the results of the previous study. Three groups of 24 mated female Sprague-Dawley rats daily received the test item, as solution in corn oil, from Day 6 to Day 20 p.c., by gavage, at dose-levels of 100, 300 or 1000 mg/kg/day. A group of 24 mated females received the vehicle only under the same experimental conditions and acted as a control group. A constant dosage-volume of 5 mL/kg/day was used. The animals were checked at least once daily for mortality and clinical signs. Body weight and food consumption were recorded at designated intervals. On Day 21 p.c., animals were sacrificed and submitted for a macroscopic post-mortem examination. A hysterectomy was performed and the numbers of corpora lutea, implantations, uterine scars, early and late resorptions and live and dead fetuses were recorded. Kidneys and livers were weighed. The fetuses were weighed, sexed and subjected to a detailed external examination, which included the observation of all visible structures, surfaces and orifices, soft tissue and skeletal (bones and cartilage) examination. A gross evaluation of placenta was undertaken. All fetuses were then discarded.

The test item concentrations in the administered dose formulations analyzed in Weeks 1 and 2 remained within an acceptable range of variations (+3.5% to +8.7%) when compared with the nominal values (± 10% of the nominal concentrations). There were 21/24, 21/24, 22/24 and 23/24 pregnant females in controls, 100, 300 and1000 mg/kg/day groups, respectively. All pregnant females had viable fetuses. There were no unscheduled deaths. Excessive salivation (recorded as ptyalism) and tremors were observed at 1000 mg/kg/day. These findings were considered to be non-adverse effects of the test item treatment. There were no effects on body weight, body weight change or food consumption at any dose-levels when compared with controls. There were no test item treatment related maternal findings at necropsy. There were no test item treatment-related effects on gravid uterus and carcass weights and hysterectomy data. A statistically significant increase was noted in mean relative liver and kidney weight values at 1000 mg/kg/day when compared with controls.

There were no effects on mean fetal body weight and sex ratio. There were no test item treatment-related findings at external examination, and soft tissue examination of the fetuses. Unossified or incomplete ossification of various part of the skeleton were noted in all litters at 1000 mg/kg/day. These findings were associated with presence of cartilage and were considered to be non-adverse effects of the test item treatment.

Diacetone alcohol was daily administered as solution in corn oil at dose-levels of 100, 300 or 1000 mg/kg/day, from Day 6 to Day 20 p.c., by oral route (gavage), to mated female Sprague-Dawley rats.

On the basis of the results obtained in this study:

- the No Observed Adverse Effect Level (NOAEL) for maternal parameters was considered to be 1000 mg/kg/day,

- the No Observed Adverse Effect Level (NOAEL) for embryo-fetal development was considered to be 1000 mg/kg/day.