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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1983
Report Date:
1983

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
insufficient number of pregnant dams/dose group, dosing from days 6-18 of gestation
Qualifier:
equivalent or similar to
Guideline:
EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
insufficient number of pregnant dams/dose group, dosing from days 6-18 of gestation
GLP compliance:
yes
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Bisphenol A Dianhydride (BPA-DA; CAS RN 38103-06-9)

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
Ninety mature New Zealand White female rabbits were obtained from Dutchland Laboratory Animals, Inc., Denver, PA for use in this study. The animals were acclimated for a minimum of 22 days prior to the initiation of the study. During the period of acclimation, the rabbits were examined for general health and appearance. The animals were uniquely identified by ear tag and provided commercial rabbit ration (Purina Lab Rabbit Chow) and tap water ad libitum. The environment of the study room was maintained at 70-78 °F, relative humidity of 53-86% and a 12-hour light/dark cycle.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
CMC (carboxymethyl cellulose)
Details on exposure:
Five groups were included in this study; for the purposes of this summary, only three groups (control, positive control, and BPA-DA treated) will be discussed. Sixteen animals per group (to obtain at least 12 pregnant) were treated with vehicle (0.5% carboxymethyl cellulose), positive control (thalidomide; 150 mg/kg/day) or BPA-DA (1000 mg/kg/day). Thalidomide and BPA-DA were suspended in vehicle to provide dose volumes of 1.5 and 2.5 mL/kg, respectively. Control dose volume was 4.0 mL/kg.
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
At Day 0 of gestation, the body weights ranged from 2845 to 4700 grams. The animals were artificially inseminated with sperm from the laboratory breeding stock five hours after induction of ovulation with chorionic gonadotropin.
Duration of treatment / exposure:
Days 6 through 18 of gestation. ( The dose was administered from gestation day (gd) 6 through 18, approximately the same time each day, and was based on each individual body weight on gd 6 (starting on gd 11, two animals in the control group, four animals in the thalidomide group and three animals in the BPA-DA group were dosed based on gd 11 body weight).)
Frequency of treatment:
Daily
Duration of test:
29 Days
Doses / concentrations
Dose / conc.:
1 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
16/group
Control animals:
yes, concurrent vehicle
other: Positive Control (Thalidomide)

Examinations

Maternal examinations:
All of the animals were observed daily for mortality, moribundity and clinical signs. Body weights were recorded on gd 0, 6, 11, 15, 19 and 29. Individual food consumption was recorded weekly.
Ovaries and uterine content:
On gd 29, the animals were sacrificed, examined for gross pathology of the external surface and viscera, and the uterus excised and weighed. The fetuses were taken by cesarean section and the following recorded for each litter: the number of corpora lutea per ovary; the number and placement of uterine implantation sites; live and dead fetuses; early and late resorptions; and any other abnormalities.
Cesarean sections were also performed on dams that were found dead, sacrificed moribund or sacrificed due to early delivery. The number of corpora lutea, implantations, resorptions and live or dead fetuses was recorded.
Fetal examinations:
Fetuses were removed from the placenta, individually identified, examined externally, weighed and measured from the frontal-parietal suture to the base of the tail (crown-rump distance).
The unfixed fetuses underwent visceral examination according to the method of Staples. All of the fetuses were opened by longitudinal incision, the sex determined and examined grossly both externally and internally. Major organs were inspected in situ with special attention to the heart and major blood vessels. The heads of approximately one-third of the fetuses were removed, fixed in Bouin’s solution, sectioned by Wilson’s freehand sectioning technique for examination of the eyes, palate, nasal septum and brain. The prepared sections were then re-examined against a light box with the aid of magnification.
Following visceral examination, all fetuses (minus the head for approximately one-third of the fetuses) were eviscerated and placed in 95% ethyl alcohol. After fixation and dehydration, the skeletons were stained in a potassium hydroxide-alizarin red solution. The skull, vertebral column, rib cage, pectoral and pelvic girdles, long bones and extremities of each skeleton were examined for degree of ossification, bone alignment, and possible anomalies. Examinations were performed with the aid of magnification on a light box.
Statistics:
Mean maternal body weight changes, food consumption, percentage data (implantations, resorptions and males), and fetal viability were analysed in the following order: Levene’s test for homogeneity of variance; if the variances proved to be homogeneous, the data were analysed by one-way classification analysis of variance (ANOVA); if the variance proved to be heterogeneous, a series of transformations was performed until homogeneity was achieved followed by ANOVA. If ANOVA was significant, the Games and Howell modification of the Tukey-Kramer honestly significant difference test was used to compare groups. Pregnancy rates were analysed by Fisher’s exact test. External, visceral, and skeletal anomalies were evaluated by a multiple proportions test. Analysis of covariance (ANCOVA) was used to analyse mean fetal weights and lengths with the litter used as the experimental unit. Levene’s test and ANOVA were evaluated at the 5% one-tailed probability level. Control vs. treatment group mean comparisons were evaluated at the 5% two-tailed probability level.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Weight loss was observed in the test material treated groups during the treatment period. Statistical evaluation of body weight change did not, however, reveal any significant differences between treated and control groups.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
No effects on food consumption were observed.
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:
no effects observed
Description (incidence and severity):
No effects in the gross pathology of the dams were observed.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Other effects:
not examined

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects: yes

Details on maternal toxic effects:
Weight loss was observed in the thalidomide- and BPA-DA-treated groups during the treatment period. Statistical evaluation of body weight change did not, however, reveal any significant differences between treated and control groups. No effects on food consumption or gross pathology of the dams were observed.
There were no differences from control in the thalidomide or BPA DA dose groups for maternal, ovarian or uterine data. The thalidomide treated group exhibited changes consistent with the known teratogenic effect of this compound.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
> 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
body weight and weight gain

Results (fetuses)

Fetal body weight changes:
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:
no effects observed
External malformations:
no effects observed
Skeletal malformations:
no effects observed
Visceral malformations:
no effects observed
Other effects:
not examined
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects: no effects

Details on embryotoxic / teratogenic effects: There were no effects on any fetal parameters from BPA-DA treatment.

Effect levels (fetuses)

Key result
Dose descriptor:
NOEL
Effect level:
> 1 000 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: teratogenicity

Fetal abnormalities

Abnormalities:
no effects observed

Overall developmental toxicity

Developmental effects observed:
no

Any other information on results incl. tables

Summary of Mean Ovarian, Uterine, and Litter Data

Parameter

Control

(Vehicle)

Thalidomide (Positive Control)

BPA-DA

(1000 mg/kg/day)

Number of dams

16

16

16

Number pregnant

14

16

13

Pregnancy rate (%)

88

100

81

Number dams surviving to gd 29

13

15*

12

    (survival  rate)

93%

100%

92%

Mean number of

   Corpora lutea

13.4

12.2

11.4

   Implantations

9.4

8.3

6.5

   Resorptions-total

1.2

5.3

2.1

   Fetuses - live

7.5

3.4

4.5

                - dead

0.5

0

0.1

Indices (mean per litter)

   Implantation  efficiency (%)

73.6

68.1

57

   Incidence of resorption (%)

17.2

61

31

   Incidence of fetal mortality (%)

3.8

0

0.9

   Incidence of fetal viability (%)

79.2

39.1

68.1

Live fetuses

   Mean body weight (g) - males

40.91

38.36

42.8

                                       - females

39.9

37.6

41.78

   Mean length (cm)        - males

9.49

9.03

9.42

                                       - females

9.33

8.92

9.39

   Percent Males

51.5

58

47.1

   Mean uterine weights - gravid (g)

485.3

228.3

315.4

* One animal died accidentally on gd 8

Summary of Mean Incidence of Abnormal Fetuses per Litter

Parameter

Control

(Vehicle)

Thalidomide (Positive Control)

BPA-DA

(1000 mg/kg/day)

External

  # of litters examined

12

11

9

  # of litters with anomalous fetuses

2

10*

3

  % of litters with anomalous fetuses

16.7

90.9

33.3

 

  Mean values (per litter)

    # of fetuses with variants

0

0.5

0

    Incidence of variants (%)

0

14.4

0

    # of fetuses with anomalies

0.3

2.7

0.6

    Incidence of anomalies (%)

2.4

64.1

8.2

Visceral - Fetal Heads

  # of litters examined

12

9

8

  # of litters with anomalous fetuses

0

3

0

  % of litters with anomalous fetuses

0

33.3

0

 

  Mean values (per litter)

    # of fetuses with variants

0

0.1

0

    Incidence of variants (%)

0

3.7

0

    # of fetuses with anomalies

0

0.4

0

    Incidence of anomalies (%)

0

16.7

0

Visceral - Torso and Limbs

  # of litters examined

12

11

9

  # of litters with anomalous fetuses

0

8*

1

  % of litters with anomalous fetuses

0

72.7

11.1

 

  Mean values (per litter)

    # of fetuses with variants

0.8

2.9

0.4

    Incidence of variants (%)

11.1

63.9

8.7

    # of fetuses with anomalies

0

1.5

0.1

    Incidence of anomalies (%)

0

38.8

1.6

Skeletal - Skulls

  # of litters examined

12

11

9

  # of litters with anomalous fetuses

0

2

0

  % of litters with anomalous fetuses

0

18.2

0

 

  Mean values (per litter)

    # of fetuses with variants

0.5

1.6

1.2

    Incidence of variants (%)

11.3

60.9

33.7

    # of fetuses with anomalies

0

0.2

0

    Incidence of anomalies (%)

0

11.4

0

Skeletal - Torso and Limbs

  # of litters examined

12

11

9

  # of litters with anomalous fetuses

0

10*

1

  % of litters with anomalous fetuses

0

90.9

11.1

 

  Mean values (per litter)

    # of fetuses with variants

0.6

3.9

0.8

    Incidence of variants (%)

6.9

91.7

16.4

    # of fetuses with anomalies

0

2.2

0.1

    Incidence of anomalies (%)

0

54.4

1.2

* Statistically significantly different from vehicle control group (p < 0.05)

Applicant's summary and conclusion

Conclusions:
Based on the results of this study, the test material is not a developmental toxin.
Executive summary:

The developmental toxicity potential of BPA-DA in the rabbit was investigated in a study conducted using methodology equivalent to OECD 414 and EPA OPPTS 870.3700 under GLP conditions (Hazleton Laboratories America, Inc., 1983).

Sixteen New Zealand White rabbits were dosed with the test material at 1000 mg/kg bw by gavage in CMC (carboxymethyl cellulose) on Days 6 through 18 of gestation. A further 16 were dosed with the vehicle alone.

A reduction in maternal bodyweight was seen at 1000 mg/kg, however, it was not statistically significant. There were no effects on any foetal parameters from test material treatment and the NOAEL for developmental toxicity was considered to be ≥1000 mg/kg bw.

Based on the results of this study, the test material is not a developmental toxin.