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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:
1972
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1972
Report Date:
1972

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Principles of method if other than guideline:
Females artifically inseminated with 0.3 mL of diluted semen from a proven donor buck using approximatley 20 x 10^6 motile sperm according to the procedure described by Vogin et al (Pharmacologist 11, 282 (1969). The females were dosed by oral gavage on Day 6 to 18 of gestation. Body weights were recorded on Days 0, 6, 12, 18 and 29 of gestation. All animals were observed daily for appearance and behaviour, including food consumption and body weight. Numbers of corpora lutea, implantation sites and resorption sites were recorded. The numbers of live and dead foetuses were recorded. Body weights of the live pups were recorded. The urogenital tract of each animal was examined in detail for normality. All foetuses underwent a detailed gross examination for the presence of external congenital abnormalities. The live foetuses were placed in an incubator for 24 hours for the evaluation of neonatal survival. All surviving pups were sacrificed and all pups were examined for visceral abnormalities by dissection. All foetuses were then cleared in potassium hydroxide, stained with alizarin red S dye and examined for skeletal defects.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
Sodium benzoate

Test animals

Species:
rabbit
Strain:
other: Dutch-belted
Details on test animals and environmental conditions:
Housed individually in mesh bottom cages
Temperature and humidity controlled
Food and fresh tap water ad libitum

Administration / exposure

Route of administration:
oral: gavage
Details on exposure:
Females were dosed by oral gavage on Day 6 to 18 of gestation.
Analytical verification of doses or concentrations:
no
Details on mating procedure:
Females artifically inseminated with 0.3 mL of diluted semen from a proven donor buck using approximatley 20 x 10^6 motile sperm according to the procedure described by Vogin et al (Pharmacologist 11, 282 (1969).
Duration of treatment / exposure:
Days 6 to 18 of gestation.
Frequency of treatment:
Daily
Duration of test:
29 days
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Remarks:
Sham exposed controls
Dose / conc.:
2.5 mg/kg bw/day (nominal)
Dose / conc.:
12 mg/kg bw/day (nominal)
Dose / conc.:
54 mg/kg bw/day (nominal)
Dose / conc.:
250 mg/kg bw/day (nominal)
No. of animals per sex per dose:
Sham treatment: 17 females mated
Positive control: 15 females mated
2.5 mg/kg bw/day: 32 females mated
12.0 mg/kg bw/day: 21 females mated
54 mg/kg bw/day: 22 females mated
250 mg.kg bw/day: 14 females mated
Control animals:
yes, sham-exposed
other:
Details on study design:
All does were subjected to Caesarean section under surgical anaesthesia on Day 29 of gestation.

Examinations

Maternal examinations:
Body weights were recorded on Days 0, 6, 12, 18 and 29 of gestation. All animals were observed daily for appearance and behaviour, including food consumption and body weight.
Ovaries and uterine content:
Numbers of corpora lutea, implantation sites and resorption sites were recorded.
Fetal examinations:
The numbers of live and dead foetuses were recorded. Body weights of the live pups were recorded. The urogenital tract of each animal was examined in detail for normality. All foetuses underwent a detailed gross examination for the presence of external congenital abnormalities. The live foetuses were placed in an incubator for 24 hours for the evaluation of neonatal survival. All surviving pups were sacrificed and all pups were examined for visceral abnormalities by dissection. All foetuses were then cleared in potassium hydroxide, stained with alizarin red S dye and examined for skeletal defects.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
effects observed, treatment-related
Dermal irritation (if dermal study):
not examined
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not examined
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:
not examined
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
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:
not examined
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not examined
Changes in number of pregnant:
no effects observed
Other effects:
no effects observed

Effect levels (maternal animals)

Key result
Remarks on result:
not determinable due to adverse toxic effects at highest dose / concentration tested

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): not examined
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 specified
External malformations:
no effects observed
Skeletal malformations:
no effects observed
Visceral malformations:
no effects observed
Other effects:
not specified

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
250 mg/kg bw/day
Based on:
test mat.
Sex:
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

Fate of doe rabbits

 

Sham

0 mg/kg bw/day

2.5 mg/kg bw/day

12.0 mg/kg bw/day

54.0 mg/kg bw/day

250 mg/kg bw/day

Positive control

Total mated

17

32

21

22

14

15

Total pregnant

10

12

10

12

10

10

Total surviving at term

16

28

21

20

12

15

Pregnant surviving at term

10

10

10

11

9

10

 

Maternal body weight (g)

 

Sham

0 mg/kg bw/day

2.5 mg/kg bw/day

12.0 mg/kg bw/day

54.0 mg/kg bw/day

250 mg/kg bw/day

Positive control

Day 0

2.69

2.25

2.30

2.53

2.62

2.78

Day 6

2.45

2.29

2.37

2.63

2.74

2.86

Day 12

2.82

2.31

2.32

2.63

2.73

-

Day 18

2.87

2.37

2.34

2.60

2.76

-

Day 29

2.90 (10)

2.47 (10)

2.38 (10)

2.64 (11)

2.86 (9)

2.95 (10)

Number of surviving dams in parenthesis

Litter data

 

Sham

0 mg/kg bw/day

2.5 mg/kg bw/day

12.0 mg/kg bw/day

54.0 mg/kg bw/day

250 mg/kg bw/day

Positive control

Total pregnancies

10

12

10

12

10

10

Died or aborted before Day 29

1

4

0

2

2

0

To term pregnancies (on Day 29)

10

10

10

11

9

10

Total corpora lutea

170

302

204

217

207

185

Mean corpora lutea/dam mated

10.0

9.44

9.71

9.86

14.8

12.3

Number of live litters

9

10

8

5

8

7

Total implant sites

59

54

55

51

65

71

Mean implant sites/dam

5.90

5.40

5.50

4.64

7.22

7.10

Total number of resorptions

6

14

13

36

12

39

Dams with 1 or more sites resorbed

3

6

4

11

5

9

Dams with all sites resorbed

1

-

1

6

1

3

Percent partial resorption

30.0

60.0

40.0

100.0

55.6

90.0

Percent complete resorption

10.0

-

10.0

54.6

11.1

30.0

Live foetuses

52

39

36

15

53

30

Average/dam

5.20

3.90

3.60

1.36

5.89

3.00

Sex ratio (M/F)

0.73

1.44

0.89

0.50

0.77

0.85

Dead foetuses

1

1

6

-

-

2

Dams with 1 or more dead foetus

1

1

1

-

-

2

Dams with all dead foetuses

-

-

1

-

-

-

Percent partial dead foetuses

10.0

10.0

10.0

-

-

20.0

Percent all dead foetuses

-

-

10.0

-

-

-

Average foetus weight (g)

38.0

35.4

36.3

41.9

38.6

32.4

Skeletal findings

 

Sham

0 mg/kg bw/day

2.5 mg/kg bw/day

12.0 mg/kg bw/day

54.0 mg/kg bw/day

250 mg/kg bw/day

Positive control

Live foetuses examined at term

50/9

39/10

36/8

15/5

53/8

26/7

Incomplete oscillation of sternebrae

 

1/1

1/1

 

 

6/4

Bipartite sternebrae

 

 

1/1

 

 

1/1

Fused sternebrae

 

2/2

 

1/1

 

8/4

Extra sternebrae

2/2

2/2

1/1

 

3/2

2/1

Fused or split ribs

 

 

 

 

 

7/4

Scrambled vertebrae

 

 

 

 

 

10/5

Scoliosis of vertebrae

 

 

 

 

 

3/2

Tail defects

 

 

 

 

 

26/7

Craniostosis

 

 

1/1

 

 

2/1

Data presented as number of foetuses affected/number of litters affected

Applicant's summary and conclusion

Conclusions:
No evidence of maternal or developmental toxicity was seen in this study.
Executive summary:

The administration of up to 250 mg/kg bw/d of sodium benzoate to pregnant rabbits for 13 consecutive days (from Day 6 to 18 of gestation) had no clearly discernible effect on nidation or on maternal or foetal survival. The number of abnormalities seen in either soft or skeletal tissues of the test groups did not differ from the number occurring spontaneously in the sham-treated controls.