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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:
weight of evidence
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Study performed 1974 before guidelines were available but meets generally accepted scientific standards with acceptable restrictions. Deficinencies are: food consumption not reported; uterine weights and corpora lutea not determined; one third used for visceral examination, should be 50%; test substance identification (batch etc) missing; no details on housing conditions/source of animals; administration only during periods of organogenesis; no explanation for dose choice, no statistics, no historical data

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1974
Report Date:
1973

Materials and methods

Test guidelineopen allclose all
Qualifier:
no guideline followed
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Version / remarks:
2001
Deviations:
yes
Remarks:
food consumption not reported; uterine weights and corpora lutea not determined; one third used for visceral examination; test substance identification missing; administration only during periods of organogenesis, no statistics, no historical data
Principles of method if other than guideline:
Adult female albino CD-1 mice were mated with young adult males. Observation of a vaginal sperm plug was considered as Day 0 of gestation. Dosing by oral intubation with a control (vehicle at level equivalent to group receiving the highest dose or aspirin at 150 mg/kg) or test article in a water suspension (10 mL/kg bw) at 4.65, 21.6, 100.0 and 465.0 mg/kg bw was carried out daily on Days 6 to 15 of gestation. Observations of body weight, appearance, behaviour, and food consumption were performed. On Day 17 of gestation all dams underwent Caesarean section. Implantation sites, resorption sites and live/dead foetuses recorded. Body weights of live pups recorded. Urogenital tract of each dam examined for anatomical normality. All foetuses examined grossly for presence of external congenital abnormalities. One third foetuses of each litter underwent detailed visceral examination and the remaining two thirds were cleared in potassium hydroxide, stained with alizarin red S dye and examined for skeletal defects.
GLP compliance:
no
Remarks:
Study predates GLP
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): FDA 71-81 (Monocalcium phosphate; monohydrate)
- Physical state: Fine white crystalline material

Test animals

Species:
mouse
Strain:
other: albino CD-1
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Outbred
- Age at study initiation: No data
- Weight at study initiation: 29.2 - 30.6 g
- Housing: Gang housing in disposable plastic cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: No data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): No data, temperature controlled rooms
- Humidity (%): No data, humidity controlled rooms

IN-LIFE DATES: No data

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
VEHICLE: Water
- Amount of vehicle (if gavage): 10 mL/kg bodyweight
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
- Impregnation procedure: cohoused
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
Duration of treatment / exposure:
10 days (Day 6 to Day 15 of gestation)
Frequency of treatment:
Daily
Duration of test:
17 days
Doses / concentrationsopen allclose all
Dose / conc.:
4.65 mg/kg bw/day (actual dose received)
Remarks:
test substance
Dose / conc.:
21.6 mg/kg bw/day (actual dose received)
Remarks:
test substance
Dose / conc.:
100 mg/kg bw/day (actual dose received)
Remarks:
test substance
Dose / conc.:
465 mg/kg bw/day (actual dose received)
Remarks:
test substance
Dose / conc.:
150 mg/kg bw/day (actual dose received)
Remarks:
Aspirin
No. of animals per sex per dose:
Table 1 Number of animals dosed
Material Dose (mg/kg) Total
Mated Pregnant
Sham 0.0 25 22
Aspirin 150.0 25 20
FDA 71-81 4.65 25 24
21.6 26 19
100.0 23 22
465.0 25 23
Control animals:
yes, sham-exposed
other: positive control: 150 mg/kg bw aspirin

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Appearence, behaviour, food consumption and weight observed daily.
DETAILED CLINICAL OBSERVATIONS: No
BODY WEIGHT: Yes
- Time schedule for examinations: Body weights recorded on days 0, 6, 11, 15 and 17.
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 17
- Organs examined: uterus and urogenital tract
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: No
- Number of implantations: Yes
- Number of resorptions: Yes
Fetal examinations:
- External examinations: Yes: one third per litter
- Soft tissue examinations: Yes: one third per litter
- Skeletal examinations: Yes: two thirds per litter
- Head examinations: Yes: two thirds per litter
Statistics:
No data
Indices:
No data
Historical control data:
No

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
not specified
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not specified
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 specified
Description (incidence and severity):
Urogenital tract was observed but no data regarding this point were described in the report.
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):
For sham- and test substance treated animals no abortions were observed. In the control group with Aspirin 1 animal died or aborted.
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
Implant sites (total number/average per dam):
0 mg/kg bw: 261 / 11.9
4.65 mg/kg bw: 283 / 11.8
21.6 mg/kg bw: 225 / 11.8
100 mg/kg bw: 244 / 11.1
465 mg/kg bw: 265 / 11.5
Aspirin: 224 / 11.8
Total litter losses by resorption:
no effects observed
Description (incidence and severity):
Resorptions:
Group (mg(kg bw): 0 4.65 21.6 100 465 Aspirin
Total number: 8 19 4 12 28 20
Dams with >=1 site resorbed: 7 13 3 10 12 9
Dams with all sites resobred: - - - - 1 -
% partial resorption: 31.8 54.2 15.8 45.5 52.2 47.4
% complete resorption: - - - - 4.35 -
Early or late resorptions:
not examined
Dead fetuses:
no effects observed
Description (incidence and severity):
Dead fetuses:
Group (mg/kg bw): 0 4.65 21.6 100 465 Aspirin
Total: 1 - - 2 4 3
Dams with 1 or more dead: 1 - - 2 3 3
Dams with all dead: - - - - - -
% partial dead: 4.55 - - 9.09 13.0 15.8
% all dead: - - - - - -
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:
not examined

Effect levels (maternal animals)

open allclose all
Key result
Dose descriptor:
NOAEL
Remarks:
maternal toxicity
Effect level:
> 465 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
clinical signs
mortality
body weight and weight gain
Key result
Dose descriptor:
NOAEL
Remarks:
developmental toxicity
Effect level:
> 465 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
number of abortions
pre and post implantation loss
dead fetuses
necropsy findings

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

Fetal body weight changes:
not examined
Description (incidence and severity):
Fetal body weights after Caesarean section were determined. The average body weights of fetuses were similar in all groups (see table 2 below).
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
Description (incidence and severity):
see table 2 for details
Changes in sex ratio:
no effects observed
Description (incidence and severity):
see tabel 2 for details
Changes in litter size and weights:
not examined
Changes in postnatal survival:
not examined
External malformations:
not examined
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
increase of incomplete ossification of sternebrae and extremities was observed in the highest dose group (see table 3 below for details)
Visceral malformations:
no effects observed
Description (incidence and severity):
see details in table 4 below

Effect levels (fetuses)

open allclose all
Key result
Dose descriptor:
NOAEL
Remarks:
fetal toxicity
Effect level:
>= 465 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
reduction in number of live offspring
Key result
Dose descriptor:
NOAEL
Remarks:
developmental toxicity
Effect level:
>= 465 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
skeletal malformations
visceral malformations

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Any other information on results incl. tables

Table 2 Reproduction data

Dose (mg/kg)

Sham

Aspirin

4.65

21.6

100.0

465.0

Pregnancies

 

 

 

 

 

 

Total No.

22

20

24

19

22

23

Died or aborted (before Day 17)

0

1

0

0

0

0

To term (on Day 17)

22

19

24

19

22

23

Live litters

 

 

 

 

 

 

Total No.*

22

19

24

19

22

22

Implant Sites

 

 

 

 

 

 

Total No.

261

224

283

225

244

265

Average/dam*

11.9

11.8

11.8

11.8

11.1

11.5

Resorptions

 

 

 

 

 

 

Total No*

8

20

19

4

12

28

Dams with 1 or more sites resorbed

7

9

13

3

10

12

Dams with all sites resorbed

--

--

--

--

--

1

Per cent partial resorptions

31.8

47.4

54.2

15.8

45.5

52.2

Per cent complete resorptions

--

--

--

--

--

4.35

Live foetuses

 

 

 

 

 

 

Total No

252

201

261

221

230

233

Average/dam*

11.5

10.6

10.9

11.6

10.5

10.1

Sex ratio (M/F)

1.02

0.88

0.78

0.92

1.13

0.93

Dead Foetuses

 

 

 

 

 

 

Total No.*

1

3

--

--

2

4

Dams with 1 or more dead

1

3

--

--

2

3

Dams with all dead

--

--

--

--

--

--

Per cent partial dead

4.55

15.8

--

--

9.09

13.0

Per cent all dead

--

--

--

--

--

--

Average foetus weight (g)

0.84

0.81

0.88

0.87

0.82

0.85

* Includes only those dams examined at term

** Positive control: 150 mg/kg

 

Table 3 Summary of skeletal findings

Findings

Dose (mg/kg)

Sham

Aspirin

4.65

21.6

100.0

465.0

Live foetuses examined (at term)

179/22

141/19

186/24

155/19

162/22

164/22

Sternebrae

 

 

 

 

 

 

Incomplete oss.

10/8

31/10

18/9

27/15

22/10

28/15

Scrambled

 

 

 

 

 

 

Bipartite

8/7

3/3

11/8

9/7

10/8

9/6

Fused

 

 

 

 

 

 

Extra

 

6/3

 

 

 

 

Missing

23/10

28/11

13/9

13/6

32/14

23/7

Other

 

 

 

 

 

 

Ribs

 

 

 

 

 

 

Incomplete oss.

 

 

 

 

 

9/4

Fused/split

 

2/2

 

 

 

 

Wavy

 

1/1

2/2

 

 

 

Less than 12

1/1

 

1/1

 

 

1/1

More than 13

48/18

30/12

42/18

18/11

32/15

34/17

Other

 

 

 

 

 

 

Vertebrae

 

 

 

 

 

 

Incomplete oss.

9/6

9/3

2/2

1/1

11/4

13/4

Scrambled

 

 

 

 

 

 

Fused

 

 

 

 

 

 

Extra ctrs. oss.

 

 

 

 

 

 

Scoliosis

 

 

 

 

 

 

Tail defects

 

 

 

 

 

 

Other

 

 

 

 

 

 

Skull

 

 

 

 

 

 

Incomplete closure

 

2/2

 

 

 

 

Missing

 

 

1/1

 

 

 

Craniostosis

 

 

 

 

 

 

Other; facial bones, inc

 

 

 

 

 

2/1

Extremities

 

 

 

 

 

 

Incomplete oss.

7/5

5/3

2/2

 

10/5

14/4

Missing

 

 

 

 

 

 

Extra

 

 

 

 

 

 

Miscellaneous

 

 

 

 

 

 

Hyoid; missing

37/16

33/11

31/15

22/12

52/15

33/13

Hyoid; reduced

17/11

25/12

17/11

21/14

15/11

27/14

* Numerator = Number of foetuses affected; Denominator = Number of litters affected

** Positive control: 150 mg/kg

 

Table 4 Summary of soft tissue abnormalities

Material

Dose level (mg/kg)

Dam

Number of pups

Description

Aspirin

150.0

A 6068

1

Cleft palate; gastroschisis

Applicant's summary and conclusion

Conclusions:
Under the conditions of the study, the test material administered to pregnant mice for 10 days up to a dose level of 465 mg/kg bw showed no maternal or developmental toxicity. The NOAEL for both maternal and developmental toxicity is > 465 mg/kg bw.