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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:
1973
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

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

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
See "Principles of method if other than guideline"
Principles of method if other than guideline:
Exposure started gestation day 6 (recommended start on day 5), dose level choice not justified (highest dose tested did not induce maternal effects), number of corpora lutea not determined, limited information on test substance included in report. No information on feed and environmental conditions, no analytical verification of doses, only average fetus weight males and females together per litter, no individual information on the pups, no historical control data, limited maternal toxicity parameters.
GLP compliance:
no
Remarks:
Study performed before GLP principles were implemented.
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Remarks:
Fine white crystalline material

Test animals

Species:
hamster
Strain:
other: Golden hamster
Details on test animals and environmental conditions:
TEST ANIMALS
- Housing: Individually housed in mesh bottom cages
- Diet: ad libitum
- Water: fresh tap water, ad libitum

ENVIRONMENTAL CONDITIONS
- The cages were kept in temperature and humidity-controlled quarters

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
Hamsters were dosed 2 mL/kg bw (high dose) or at 1 mL/kg bw.
Analytical verification of doses or concentrations:
no
Details on mating procedure:
Females were mated with young adult males (1 to 1), and appearance of motile sperm in the vaginal smear was considered Day 0 of gestation.
Duration of treatment / exposure:
Five consecutive days (day 6 to day 10 of gestation).
Frequency of treatment:
Daily gavage.
Duration of test:
On gestation Day 14, all dams were sacrificed.
Doses / concentrationsopen allclose all
Dose / conc.:
2.72 mg/kg bw/day (actual dose received)
Remarks:
No analytical verification of exposure.
Dose / conc.:
12.6 mg/kg bw/day (actual dose received)
Remarks:
No analytical verification of exposure.
Dose / conc.:
58.7 mg/kg bw/day (actual dose received)
Remarks:
No analytical verification of exposure.
Dose / conc.:
272 mg/kg bw/day (actual dose received)
Remarks:
No analytical verification of exposure.
No. of animals per sex per dose:
Pregnant females: 22 (negative control), 19-24 (positive control groups), 22 (groups exposed to 2.72 and 12.6 mg/kg bw/day), 23 (groups exposed to 58.7 and 272.0 mg/kg bw/day).
Control animals:
yes
yes, concurrent vehicle

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
- Appearance and behaviour with particular attention to food consumption and weight.

BODY WEIGHT: Yes
- Time schedule for examinations: Gestation days 0, 8, 10, and 14

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation Day 14
- Examinations: Number of implantation sites, resorption sites, live and dead fetuses; The urogenital tract of each dam was examined in detail for anatomical abnormalities.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
Number of implantation sites, resorption sites, live and dead fetuses
Fetal examinations:
- Body weight (live pups)
- External examinations: Yes: All per litter
- Soft tissue examinations: Yes: One-third per litter
- Skeletal examinations: Yes: Two-third per litter

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
not specified
Mortality:
mortality observed, non-treatment-related
Description (incidence):
One control hamster and one high dose hamster died during the study. All other dams survived until sacrifice.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Weight increase of exposed groups was comparable to negative control group (based on average value, standard deviations not included).
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not specified
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 specified
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
not specified
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Number of abortions:
no effects observed
Description (incidence and severity):
No abortions were observed.
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
The average number of implantation sites per dam was 13.8, 13.4, 13.3, 13.2 and 13.2 for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively. The average number of live fetuses per dam were 13.4, 13.0, 12.8, 12.7 and 12.9 for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively. The exposure to the test substance did not have effect on implantation loss.
Total litter losses by resorption:
no effects observed
Description (incidence and severity):
All pregnant dams had live litters.
Early or late resorptions:
no effects observed
Description (incidence and severity):
The total number of resorptions was 8, 9, 5, 9 and 8 for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively. The number of dams with one or more sites resorbed was 5, 4, 4, 6 and 6 for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively.The percentage of dams with partial resorptions was 23.8%, 18.2%, 18.2%, 26.1% and 27.3% for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively.
Dead fetuses:
effects observed, non-treatment-related
Description (incidence and severity):
No dead fetuses were found in the control group. In the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, 0, 7, 1 and 0 dead fetuses were found, respectively. The 7 dead fetuses were found in one nest. In absence of a dose-relationship, the dead fetuses were concidered not to be related to the test substance.
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
Description (incidence and severity):
All pregnant dams that survived to term had live litters.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
>= 272 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: No effects seen up to and including the highest dose tested.

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

Fetal body weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
The average fetus weight was 1.78, 1.79, 1.81, 1.78 and 1.84 g for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively.
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:
not examined
Changes in sex ratio:
no effects observed
Description (incidence and severity):
The sex ratio (M/F) for the live fetuses was 0.74, 0.81, 0.75, 0.77 and 0.67 for the negative control group and the groups exposed to 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day, respectively.
Changes in litter size and weights:
not examined
Changes in postnatal survival:
not examined
External malformations:
no effects observed
Description (incidence and severity):
No external malformations were noted in any of the groups.
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
The number of skeletal malformations in the exposed groups did not differ from the control group (results summarized below).
Visceral malformations:
effects observed, non-treatment-related
Description (incidence and severity):
At 58.7 mg/kg bw/day, one pup was found with meningoencephalocele. No other visceral malformations were found in the groups exposed to citric acid and in the negative control group. This was regarded as an incidental finding.

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
>= 272 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No effects seen up to and including highest dose tested.

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Any other information on results incl. tables

Summary of skeletal findings (number of foetuses affected/ number of litters affected)

 

Control

2.72 mg/kg bw/day

12.6 mg/kg bw/day

58.7 mg/kg bw/day

272.0 mg/kg bw/day

Live fetuses examined (pregnant dams)

194 (21)

196 (22)

194 (22)

203 (23)

196 (22)

Sternebrae

Incomplete ossification

95/21

93/21

66/18

104/22

72/19

Bipartite

11/7

23/13

15/10

22/13

17/10

Extra

1/1

2/2

8/6

2/2

1/1

Missing

30/12

27/15

15/7

21/8

15/9

Ribs

Incomplete ossification

1/1

 

 

 

 

Fused/split

1/1

 

1/1

 

 

Wavy

3/3

 

 

 

 

Less than 12

2/1

 

 

 

 

More than 13

41/15

59/18

57/21

61/17

43/19

Vertebrae

Incomplete ossification

4/4

6/3

2/2

1/1

2/2

Skull

Incomplete closure

 

 

1/1

 

 

Extremities

Incomplete ossification

5/4

6/4

1/1

1/1

2/2

Miscellaneous

Hyoid, missing

4/4

3/2

1/1

 

1/1

Hyoid, reduced

4/3

4/3

6/4

4/4

2/2

 

Applicant's summary and conclusion

Conclusions:
Hamsters were exposed to citric acid at 0, 2.72, 12.6, 58.7 and 272.0 mg/kg bw/day via oral gavage for 5 consecutive days during pregnancy (gestation days 6 to 10). No effects were seen in maternal animals or fetuses. The nature and number of abnormalities seen in skeletal and soft tissues of the test groups did not differ from the controls. Based on these results, it is concluded that the NOAEL (maternal and development) is at least 272.0 mg/kg bw/day in hamsters.