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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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study (analytical purity of test substance not specified, number of animals with implantation sites per group was below 16, limited documentation, only organogenesis covered (days 6-18 of gestation)).

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1974
Report Date:
1974

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
(analytical purity of test substance not specified, number of animals with implantation sites per group was below 16, limited documentation)
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): FDA 71-31, sorbitol
- Physical state: fine white crystalline material

Test animals

Species:
rabbit
Strain:
Dutch
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 2.07-2.51 kg
- Housing: singly
- Diet (ad libitum)
- Water (ad libitum): tap water

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
VEHICLE
- Amount of vehicle (if gavage): 1, 2, 3, 4, 5, 6, 6.4 for the respective 2.5, 16, 74.3, 345, 1600 mg/kg bw/day dose group
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
- Impregnation procedure: [artificial insemination]
On day 0, each doe was given an injection of 0.4 mL of human chorionic gonadotropin (400 IU) via the marginal ear vein. Three hous later, each doe was inseminated artificically with 0.3 mL of diluted semen from a proven donor buck using approximately 20000000 motile sperm according to the procedure described by Vogin et al. (Pharmacologist 11, 282 (1969)).
Duration of treatment / exposure:
day 6-18 of gestation
Frequency of treatment:
daily
Duration of test:
29 days
Doses / concentrations
Remarks:
Doses / Concentrations:
16, 74.3, 345, 1600 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
13 (control group, 1600 mg/kg bw/day)
10 (2.5 mg/kg 6-aminonicotinamide)
12 (16, 74.3, 345 mg/kg bw/day)
Control animals:
yes, sham-exposed

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: on days 0, 6, 12, 18, and 29 of gestation

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- daily observation, but no recording

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 29 (caesarean section under surgical anesthesia)
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of resorptions: Yes
Fetal examinations:
- External examinations: Yes: [all pups per litter]
- Soft tissue examinations: Yes: [all pups per litter]
- Skeletal examinations: Yes: [all pups per litter], cleared in potassium hydroxide, stained with alizarin red dye and examined)
- Head examinations: Yes: [all pups per litter]
After detailed gross examination for the presence of external congenital abnormalities, the live fetuses of each litter were placed in an incubator for 24 hours for the evalutation of neonatal survival. All survivng pups were then sacrificed and examined for visceral and skeletal abnormalities.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:no effects

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
>= 1 600 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
The following soft tissue abnormalities were found:
Control group: 1 pup with medial rotation of hind limbs.
Positive control group: Several pups of different dams showed treatment-related anopia, medial rotation of hind limbs, harelip, and/or short tails.
74.3 mg/kg bw dose group: 1 pup with microcephaly was observed. This effect was assumed to be a chance finding.

Partial resorptions increased with the dose, but at the highest administered dose a value of 25% was evaluated which was similar to controls (23%). The total number of live fetuses and the average number of live fetuses/dam decreased with the dose. The toxicological relevance is questionable and effects in other species have also to be taken into account.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
>= 1 600 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: teratogenicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Table 1: Average maternal body weights (in kg)

 

 Day

 

0

6

12

18

29

Dose group

 

 

 

 

 

Sham

2.28

2.37

2.42

2.57

2.65 (13)

Positive Control

2.51

2.58

2.64 (10)

2.8 (8)

2.71 (10)

16 mg/kg bw TS

2.14

2.30

2.29

2.37

2.55

(12)

74.3 mg/kg bw TS

2.07

2.14

2.2

2.29

2.45

(12)

345 mg/kg bw TS

2.14

2.22

2.24

2.32

2.41

(12)

1600 mg/kg bw TS

2.15

2.26

2.3

2.39

2.4

(12)

- TS: test substance

- number of surviving dams in parentheses

Table 2: Litter response (caesarean section data)

Dose group

Sham

Positive Control

16 mg/kg bw TS

74.3 mg/kg bw TS

345 mg/kg bw TS

1600 mg/kg bw TS

Pregnancies

 

 

 

 

 

 

Total No.

13

10

12

12

12

13

Died or aborted (before day 29)

0

0

0

0

0

1

To term (on day 29)

13

10

12

12

12

12

Corpora lutea

 

 

 

 

 

 

Total No.

152

145

161

195

150

176

Average/dam mated

10.1

13.2

10.7

13.9

10.7

11

Live litters

 

 

 

 

 

 

Total No.

13

8

12

12

12

9

Implant Sites

 

 

 

 

 

 

Total No.

85

70

73

80

64

66

Average/dam

6.54

7

6.08

6.67

5.33

5.5

Resorptions

 

 

 

 

 

 

Total No.

5

6

2

1

2

6

Dams with 1 or more sites resorbed

3

3

1

1

2

3

Dams with all sites resorbed

--

1

--

--

--

2

% partial resorptions

23.1

30

8.33

8.33

16.7

25

% complete resorptions

--

10

--

--

--

16.7

Live fetuses

 

 

 

 

 

 

Total No.

80

56

71

79

62

54

Average/dam

6.15

5.6

5.92

6.58

5.17

4.5

Sex ratio (M/F)

1.05

1

1.22

1.11

1.22

1.52

Dead Fetuses

 

 

 

 

 

 

Total No.

--

8

--

--

--

6

Dams with 1 or more dead

--

1

--

--

--

1

Dams with all dead

--

1

--

--

--

1

% partial dead

--

10

--

--

--

8.33

% all dead

--

10

--

--

--

8.33

Average fetus weight (g)

36.7

36.1

38.9

36.8

38.2

39.4

Table 3: Summar of skeletal findings

Dose group

Sham

Positive Control

16 mg/kg bw TS

74.3 mg/kg bw TS

345 mg/kg bw TS

1600 mg/kg bw TS

Live Fetuses (at term)

80/13

56/8

71/12

79/12

62/12

54/9

Sternebrae

 

 

 

 

 

 

Incomplete oss.

--

3/2

1/1

1/1

3/3

2/2

Scrambled

--

--

--

--

--

--

Bipartite

--

--

--

1/1

1/1

1/1

Fused

1/1

1/1

1/1

2/1

1/1

1/1

Extra

--

2/2

1/1

3/1

1/1

1/1

Missing

1/1

2/2

--

1/1

--

1/1

Other

--

--

--

--

--

--

Ribs

--

--

--

--

--

--

Incomplete oss.

--

--

--

--

--

--

Fused/Split

--

7/4

--

--

--

--

Wavy

--

--

--

--

--

--

Less than 12

--

--

--

--

--

--

More than13

--

--

--

--

--

--

Other

--

--

--

--

--

--

Vertebrae

--

--

--

--

--

--

Incomplete oss.

--

--

--

--

--

--

Scrambled

1/1

7/4

--

--

--

1/1

Fused

--

--

--

--

--

--

Extra ctrs. oss.

--

--

--

--

--

--

Scoliosis

--

1/1

--

--

--

--

Other

--

31/5

--

--

--

--

Applicant's summary and conclusion

Conclusions:
The test substance had no effect on intrauterine development.