Reaction mass of 2-[[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]methyl]oxirane and 1,3-bis[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]propan-2-ol and 1-[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]-3-[4-[[4-[3-[4-[[3,5-dimethyl-4-(oxiran-2-ylmethoxy)phenyl]methyl]-2,6-dimethyl-phenoxy]-2-hydroxy-propoxy]-3,5-dimethyl-phenyl]methyl]-2,6-dimethyl-phenoxy]propan-2-ol

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,3-bis[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]propan-2-ol; 1-[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]-3-{4-[(4-{3-[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]-2-hydroxypropoxy}-3,5-dimethylphenyl)methyl]-2,6-dimethylphenoxy}propan-2-ol; 2-{[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]methyl}oxirane

EC Number:

941-357-0

Molecular formula:

Not applicable for multi-constituent substances

IUPAC Name:

1,3-bis[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]propan-2-ol; 1-[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]-3-{4-[(4-{3-[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]-2-hydroxypropoxy}-3,5-dimethylphenyl)methyl]-2,6-dimethylphenoxy}propan-2-ol; 2-{[4-({3,5-dimethyl-4-[(oxiran-2-yl)methoxy]phenyl}methyl)-2,6-dimethylphenoxy]methyl}oxirane

Test material form:

liquid

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Crl:WI(Han)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Margate, United Kingdom,
- Age at study initiation: 8 to 10 weeks old at time of mating
- Weight at study initiation: Between 172.5 and 250.2 g at the start of dosing.
- Fasting period before study: No
- Housing: Animals were housed in cages that conform to the Code of Practice for the Housing and Care of Animals Bred, Supplied or Used for Scientific Purposes (Home Office, 2014). Animals were individually housed in a single, exclusive room.
- Diet (e.g. ad libitum): Animals had ad libitum access to VRF1 diet. Each batch of diet was analyzed for specific constituents and contaminants. No contaminants were present in the diet at levels which might have interfered with achieving the objective of the study. Results are retained on file at the testing laboratory.
- Water (e.g. ad libitum): Water from the main tap supply was provided ad libitum via water bottles. The water is periodically analyzed for specific contaminants. No contaminants were present in the water at levels which might have interfered with achieving the objective of the study. Results are retained on file at the testing laboratory.
- Acclimation period: Approximately 3 to 4 days. Acclimation was limited by mated status, and an inspection was performed by the Named Animal Care and Welfare Officer (NACWO) before the start of dosing to ensure suitability for the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 30 to 70%
- Air changes (per hr): A minimum of 15 to 20 air changes per hour.
- Photoperiod (hrs dark / hrs light): 12 hour light dark cycle.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Remarks:

PEG400

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Formulations were prepared weekly. The test article was formulated as a solution in PEG 400 following dispensary SOPs and an approved formulation method, as maintained in the study data. Formulations were stored at room temperature (15 to 25°C) in a sealed container, protected from the light.

- VEHICLE
- Justification for use and choice of vehicle (if other than water): standard vehicle deemed suitable for use with the substance.
- Concentration in vehicle: 0, 20, 60 and 120 mg/mL
- Amount of vehicle (if gavage) 5 mL/kg

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Formulations prepared at 1 and 200 mg/mL were shown to be stable for 12 days at room temperature (15 to 25°C) and homogenous.

Formulations prepared for use on the first and last day of dosing were analyzed to determine the achieved concentration. Triplicate samples were removed from the middle of the test article formulations and were analyzed. A single sample was taken from the middle of control formulations and was analyzed. The mean % nominal concentration should be between 85 to 115% and with a relative standard deviation (RSD) ≤10.0%. Results were within these criteria.

Details on mating procedure:

- Impregnation procedure: purchased timed pregnant
- Proof of pregnancy: Mating (overnight at the supplier’s laboratory) was confirmed by the presence of a vaginal plug in situ, or other evidence of mating, if necessary. The day on which mating was confirmed was designated as GD 0.

Duration of treatment / exposure:

Animals were dosed once daily from GD 6 to 20. Females were maintained to GD 21, when they were sacrificed, and their uterine contents were examined.

Frequency of treatment:

Daily

Duration of test:

Animals arrived GD 3 to 4 and were dosed from GD 6 to 20 with sacrifice on GD 21.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 mg/kg bw/day (nominal)

Remarks:

Low

Doses / concentrations 2

Dose / conc.:

300 mg/kg bw/day (nominal)

Remarks:

Intermediate

Doses / concentrations 3

Dose / conc.:

600 mg/kg bw/day (nominal)

Remarks:

High

No. of animals per sex per dose:

20 females per sex per group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Doses selected based on the results of a previously conducted OECD 422 study.
- Rationale for animal assignment (if not random): Animals were assigned to dose groups based on GD 0 body weight data obtained from the Supplier (i.e., all animals confirmed as mated on a specific day were randomly allocated to dose groups). Animals were individually identified by electronic implant.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: All animals were observed at the beginning and end of the working day for signs of ill health or overt toxicity. Animals were observed daily for the first 3 days upon return to home cage and approximately 1, 2, and 4 hours postdose.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Each animal was given a detailed physical examination daily from GD 6 to necropsy. An individual record of the clinical condition of each animal was maintained.

BODY WEIGHT: Yes
- Time schedule for examinations: Body weights were recorded on GD 5, 6, 7, 8, 9, 12, 15, 17, 19, 20, and 21.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes / No / No data
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: The amount of food consumed was determined from GD 6 to 21. Food consumption was calculated as g/animal/day.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: Animals examined macroscopically and all lesions were recorded and retained in the relevant fixative.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Pregnancy status: Yes
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Number and position of implantations suvdivided into live fetuses, early intrauterine deaths, late intrauterine deaths and dead fetuses. Early intrauterine deaths were classified as those which showed decidual or placental tissue only. Late intrauterine deaths showed embryonic or fetal tissue, in addition to placental tissue. Dead fetuses were classified as those which appeared to have died shortly before necropsy. Implantations/fetuses were allocated numbers relating to their position in utero. The uterus of any apparently non-pregnant female was immersed in a 10% ammonium sulphide solution to reveal any evidence of implantation.

Fetal examinations:

Live fetuses were sacrificed by a subcutaneous injection of sodium pentobarbitone followed by confirmation of cessation of circulation. Individual fetal and placental weights were recorded, and fetuses were examined externally and sexed. Approximately one half of the fetuses in each litter, selected by systematic sampling, were dissected, and the viscera were examined. Fetuses were then eviscerated, and carcasses were cleared in potassium hydroxide. Skeletons were stained with Alizarin Red S, retained in glycerol/propylene glycol, and examined for skeletal and cartilaginous abnormalities. The remaining fetuses were fixed in Bouin's fluid, and the viscera were examined. Fetuses fixed for visceral examination were retained in the relevant fixative. Fetal abnormalities were classified as malformations (rare and/or potentially lethal defects) or variations (commonly occurring non-lethal abnormalities).

Statistics:

When tables/appendices are computer generated, rounding of individual values may occur during the calculation of derived values. Therefore, recalculation of derived values from the individual data, as presented in this report, may have, in some instances, yielded minor variations.

Data from test article-treated animals were compared with control data. Statistical analyses were performed, where appropriate. Data for each sex were analyzed separately, unless stated otherwise. Except where otherwise stated, tests were performed using a two-sided risk and were considered significant where P ≤ 0.05. By default, significant results were reported as * = P ≤ 0.05, + = P ≤ 0.01, # = P ≤ 0.001.

Only data collected on or after the first day of dosing were analyzed statistically. The following data were analyzed using Pristima:
- Body weights - Procedure I (ANOVA)
- Body weight gains - Procedure I (ANOVA)
- Food consumption - Procedure I (ANOVA)
- Mean fetal weight (male, female, and combined) Procedure II (litter size [live and dead fetuses] as the covariate)
- The number of corpora lutea, implantation sites, early and late resorptions, dead fetuses, live fetuses, percent pre- and post-implantation loss, and percent male fetuses - Procedure III
- Gravid uterine weights and corrected body weights (carcass weights) - Procedure I
(ANOVA)
- The percentage of fetuses affected (mean litter percent) - Procedure III
- Proportion of litters affected - Procedure IV (one-sided upper tail)

Indices:

% pre/post-implantation loss, corrected body weight (carcass weight), corrected weight change, total weight change and % male fetuses were calculated.

Historical control data:

Results observed considered against historical control data.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

No test article-related clinical observations were detected. Isolated instances of fur staining, thinning fur, and/or minimal sores/lesions were noted in a few animals across all groups, including controls. These observations are commonly noted in the background data for this species and strain, and were on no toxicological importance.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No unscheduled deaths occurred during the study.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Test article-related effects on body weight and body weight gain were noted for animals administered 300 or 600 mg/kg/day.

Initial reduction in body weight was noted after the first dose administration (between GD 6 and 7) for animals administered 300 or 600 mg/kg/day (P<0.05 or P<0.01), respectively. Animals administered 600 mg/kg/day continued to show effects on body weight, with reduced body weight gain noted for the duration of the study, compared with controls. The reduction in body weight gain between GD 6 and 21 (-13% compared with control; P<0.05) attained statistical significance.

Animals administered 300 mg/kg/day showed recovery from GD 7 onwards.

No effect on body weight was noted for animals administered 100 mg/kg/day, compared with controls.

Total weight change, corrected weight change, carcass weight and gravid uterus weights were lower for females administered 600 mg/kg/day, compared with controls, although statistical significance was never achieved.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A test article-related reduction of food consumption was noted in animals administered 300 and 600 mg/kg/day.

An initial reduction in food consumption of -16% or -26% of control values was noted between GD 6 and 7 for animals administered 300 or 600 mg/kg/day, respectively. Animals administered 600 mg/kg/day continued to show effects on food consumption for the duration of the study, compared with controls. The mean reduction in food consumption between GD 6 and 21 was approximately 11% of control values.

Animals administered 300 mg/kg/day showed recovery from GD 7 onwards. No effect on food consumption was noted for animals administered 100 mg/kg/day compared with controls.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

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:

not examined

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No test article-related macroscopic observations were noted.

Observations, including dark contents in the stomach, pelvic dilatation of the kidney, and large placenta, were noted in animals across all groups, including controls. These observations showed no dose relationship, were observed at a low incidence, and/or are commonly observed background findings; as such, they were considered incidental.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Maternal developmental toxicity

Number of abortions:

no effects observed

Description (incidence and severity):

Abortions not a common occurence in rats.

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

No effects observed.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Total litter losses by resorption:

no effects observed

Description (incidence and severity):

No effects observed

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Early or late resorptions:

no effects observed

Description (incidence and severity):

No effects observed

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Dead fetuses:

effects observed, non-treatment-related

Description (incidence and severity):

One female administered 600 mg/kg/day were found to have no viable fetuses (100% in utero litter loss). No viable fetuses was also noted in one control female and as such, these findings were considered to have arisen incidentally, and of no toxicological significance.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Changes in pregnancy duration:

no effects observed

Description (incidence and severity):

No effects noted. All animals sacrified on GD 21 as scheduled.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Changes in number of pregnant:

effects observed, non-treatment-related

Description (incidence and severity):

One control animal, two animals administered 300 mg/kg/day, and five animals administered 600 mg/kg/day were found to be non-pregnant.

The animals were time-mated at the animal suppliers prior to arrival at the test facility or the administration of any test article; as such the high incidence of non-pregnant animals noted in this study was unrelated to test article administration, and considered incidental.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Other effects:

not specified

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Maternal abnormalities

Abnormalities:

no effects observed

Results (fetuses)

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

Lower mean fetal body weight, adjusted for litter size was noted for 600 mg/kg/day litters, compared with controls, and statistical significance was achieved for males (P<0.001), females (P<0.05) and combined fetal weights (P<0.01).

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

No effects observed

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Changes in sex ratio:

no effects observed

Description (incidence and severity):

No effects observed

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Changes in litter size and weights:

effects observed, treatment-related

Description (incidence and severity):

Lower mean fetal body weight, adjusted for litter size was noted for 600 mg/kg/day litters, compared with controls, and statistical significance was achieved for males (P<0.001), females (P<0.05) and combined fetal weights (P<0.01).

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Changes in postnatal survival:

not examined

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

No test article-related fetal malformations were noted. Fetal malformations were noted in one fetus each from four control litters, three fetuses in two litters of dams administered 100 mg/kg/day, and two fetuses in two litters of dams administered 600 mg/kg/day. Fetal malformations showed no dose relationship, the majority of individual malformations were noted in the same number of fetuses in litters of control dams and dams administered 600 mg/kg/day, and/or the malformations are noted in historical background controls; as such, they were considered incidental.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information.

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

No test article-related fetal malformations were noted. Fetal malformations were noted in one fetus each from four control litters, three fetuses in two litters of dams administered 100 mg/kg/day, and two fetuses in two litters of dams administered 600 mg/kg/day. Fetal malformations showed no dose relationship, the majority of individual malformations were noted in the same number of fetuses in litters of control dams and dams administered 600 mg/kg/day, and/or the malformations are noted in historical background controls; as such, they were considered incidental.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information alongside Text Tables 1 and 2 in the section 'any other information on results incl. tables'.

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

No test article-related fetal malformations were noted. Fetal malformations were noted in one fetus each from four control litters, three fetuses in two litters of dams administered 100 mg/kg/day, and two fetuses in two litters of dams administered 600 mg/kg/day. Fetal malformations showed no dose relationship, the majority of individual malformations were noted in the same number of fetuses in litters of control dams and dams administered 600 mg/kg/day, and/or the malformations are noted in historical background controls; as such, they were considered incidental.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information alongside Text Tables 1 and 2 in the section 'any other information on results incl. tables'.

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Test article-related fetal variations included a higher incidence of thin cartilaginous structures of the vertebra sacral arch, which affected 64% of litters from the
600 mg/kg/day dose group, compared with 22% of litters from the control dose group; statistical significance of P<0.05 was achieved.

Other test article related variations included an increase in malpositioned cartilaginous ventral plate of the vertebra central arch, and increased incidence of unossified phalanx and incomplete ossification of the phalanx in litters from 300 and 600 mg/kg/day, compared with controls. Although values were within the historical control background range, the increased incidence was considered to be test article related, however, was considered not to represent an adverse effect of test article administration.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information alongside Text Tables 1 and 2 in the section 'any other information on results incl. tables'.

Details on embryotoxic / teratogenic effects:

Although no test article-related fetal malformations were noted, a higher incidence of skeletal variations in the vertebra and hindlimb were noted following 300 or 600 mg/kg/day administration, compared with controls. These included a higher incidence of thin cartilaginous structures (vertebra sacral arch), the only variation achieving statistically significant statistical significance at P<0.05, and an increase in malpositioned cartilaginous ventral plate (vertebra central arch) in 600 mg/kg/day litters, and increased incidences of unossified phalanx or incomplete ossification of the phalanx (hindlimb) in litters from 300 and 600 mg/kg/day.

The increased incidences of skeletal variations noted following 300 or 600 mg/kg/day were considered test article-related, however, values for the majority of the fetal variations were within the historical control background ranges, and all changes were considered not to representative of an adverse effect of test article administration.

See attached summary tables (TMBPF-DGE_PNDT Summary Tables) for more information alongside Text Tables 1 and 2 in the section 'any other information on results incl. tables'.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

600 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Remarks on result:

not determinable due to absence of adverse toxic effects

Fetal abnormalities

Abnormalities:

effects observed, treatment-related

Overall developmental toxicity

Developmental effects observed:

no

Any other information on results incl. tables

Text Table 1: Noteworthy Fetal Variations:

Tissue	Variation	HCD Range (% litters)	Dose level (mg/kg/day)
			0 (control)	100	300	600
			Number litter/fetuses (% litters) affected
Vertebra -	Cartilaginous ventral	Mean: 1.3% Range: 0 – 1%	1/1	1/1	2/2	4/6
Cervical arch	plate - malpositioned.		(6%)	(5%)	(11%)	(29%)
Vertebra -	Cartilaginous structures	No data	4/5	3/4	5/6	9/10
Sacral arch	- thin		(22%)	(15%)	(28%)	(64%)
						P< 0.05
Hindlimb	Phalanx – incomplete ossification.	Mean: 30% Range: 5 – 60%	4/6	4/9	6/10	6/8
			(22%)	(20%)	(33%)	(43%)
Hindlimb	Phalanx - unossified.	Mean: 51% Range: 0 – 85%	3/3	2/4	4/6	3/6
			(17%)	(10%)	(22%)	(21%)

Text Table 2: Fetal malformations:

Group	Dam Number	Fetus ID & sex	Malformation
0 mg/kg/day	R0007	R7 Male	Thyroid: absent - right
	R0012	L2 Female	Sternebra: absent - 5
	R0013	L2 Male	Situs inversus - complete
			Rib: abnormal attachment, vertebral end - 1, bilateral
			Skull: Exoccipital/vertebral cervical arch fused - bilateral
			Sternebra: Fused - 1/2
			Sternebra: Misaligned - 2
			Vertebra: cervical arch: Misshapen - 1, bilateral
			Vertebra: cervical arch: Thick cartilaginous neural arch - 2, right
			Vertebra: cervical centrum: Fused, cartilaginous - 3/4
			Vertebra: cervical centrum: Misshapen - 1
			Vertebra: cervical centrum: Split - 1
	R0017	L4 Male	Vertebra: sacral: Small - 1, 2, 3, and 4
			Vertebra: sacral arch: Misaligned - bilateral, 1
			Vertebra: sacral centrum: absent - 3
			Vertebra: sacral centrum: Hemicentric, left side present - 4
			Vertebra: sacral centrum: Split - 1
			Vertebra; thoracic centrum: Split - 6 and 13
100 mg/kg/day	R0105	L3 Female	Kidney: Hydronephrosis - left
			Mouth: Cleft palate
		R10 Female	Vertebra: cervical arch: Fused to cartilaginous ventral plate- left, 5/6
	R0107	R9 Female	Blood Vessel; subclavian artery: Retroesophageal, right, arising from descending aorta
			Liver: Abnormal lobulation
600 mg/kg/day	R0303	L1 Female	Skull: Incisor: Misshapen, long - lower left
	R0306	L6 Male	Vertebra: cervical arch: fused to cartilaginous ventral plate - bilateral, 5

Applicant's summary and conclusion

Conclusions:

Once daily oral (gavage) administration of 0 (control article [vehicle]), 100, 300, or 600 mg/kg/day to the pregnant rat from implantation to the day before parturition, resulted in test article-related changes at all dose levels.

Effects on maternal body weight and food consumption resulted in lower total weight change, corrected weight change, carcass weight and gravid uterine weights were lower for dams administered 600 mg/kg/day. Although an initial reduction in body weight and food consumption was evident following 300 mg/kg/day administration, no other maternal changes were evident. As such, the no observed adverse effect level (NOAEL) for maternal toxicity was established as 300 mg/kg/day.

Fetal effects consisted of slightly lower but statistically significant body weights following maternal administration of 600 mg/kg/day, and higher incidences of several skeletal variations following maternal administration of 300 or 600 mg/kg/day, although only one vertebral variation (thin cartilaginous structures of the vertebra sacral arch) reached statistical significance. These effects were considered non-adverse. Based on the findings of this study, the fetal no observed adverse effect level (NOAEL) is established as 600 mg/kg/day.