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Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March - September 1985
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:
1987
Report Date:
1987

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report (developmental test): Scopolamine hydrobromide trihydrate- Molecular formula (if other than submission substance): C17H21NO4*HBr*3H2O- Molecular weight (if other than submission substance): 438.31 g/mol- Physical state: white crystalline powder, odourless- Solubility: Miscible in water (1.0 g / 1.5 mL) - Analytical purity: 98.9%; 89% scopolamine hydrobromide and 11% water- Supplier: Rebeco Chemicals, Inc.- Purchase Order Date: 03.01.1984- Lot/batch No.: 14188/01

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratory, Inc. (Kingston, NY).
- Age at study initiation: male 10-12 weeks; female 8-10 weeks
- Weight at study initiation: females 200-275 g
- Housing: male individually/females 4 animals per cage
- Diet (e.g. ad libitum): ad libitum (Purina certified rodent Chow (TM), pelletized)
- Water (e.g. ad libitum): ad libitum, deionized/filtered water
- Acclimation period: 7 days quarantine period- Insemination: via copulation
ENVIRONMENTAL CONDITIONS
- Temperature: 68-72°F; 20-22°C
- Humidity: 29.4 to 49.1 %
- Air changes (per hr): 12 to 14 changes per hr- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
Route = oral
REPARATION OF DOSING SOLUTIONS:
Scopolamine hydrobromide trihydrate will be measured into a volumetric flask, distilled water will be added to the mark , and a uniform solution will be formed by agitating the flask. Solutions will be stored in screw cap bottles at room temperature and agitated prior to dosing.
VEHICLE
- Justification for use and choice of vehicle (if other than water): None required
- Concentration in vehicle: preliminary toxicity study: 0-240 mg/mL; teratology study: 0-180 mg/mL
- Amount of vehicle (if gavage): 5 mL/kg bw
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
preliminary study: 0, 100, 300, 600, 900 or 1200 mg/kg bw/day
teratology study: 0, 10, 100, 450, or 900 mg/kg bw/day
Deionized water solutions of scopolamine hydrobromide trihydrate at a concentration of 11 mg/ml are stable for 3 weeks in the dark at room temperature. Dosed water stored for 3 hr open to air and light is also stable.
Details on mating procedure:
- Impregnation procedure: cohoused
- M/F ratio per cage: 1:1
- Length of cohabitation: overnight
On the following morning the females were examined by vaginal smear for the presence of sperm. Females which were negative for sperm were returned to group cages with other nonpregnant females. Sperm-positive females were individually housed through scheduled sacrifice (gd 20). The day on which sperm were found was designated as gestational day gd. zero.
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
Duration of treatment / exposure:
Daily administration between day 6 to 15 of gestation
Frequency of treatment:
once per day
Duration of test:
20 days
- Observation from gestation day 6 to 20 of gestation
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Dose / conc.:
10 mg/kg bw/day (nominal)
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
450 mg/kg bw/day (nominal)
Dose / conc.:
900 mg/kg bw/day (nominal)
No. of animals per sex per dose:
- 21-28 pregnant females per dose
- 12-16 animals per dose group in each replicate
Control animals:
yes, concurrent vehicle
Details on study design:
- Sex: female
- Duration of test: Through day 20 of gestation
- Dose selection rationale: A high dose was selected on the results of the preliminary study. The high dose was expected to produce significant signs of maternal and/or foetal toxicity while allowing 90% or greater maternal survival through gestation day 20. The selected high dose, at least two lower doses and vehicle control were administered to timed-pregnant CD rats on gestational days 6 through 15.

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once daily during treatment period (gestational day 6-15)
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once daily from gestational day 6 to 15 and 20
BODY WEIGHT: Yes
- Time schedule for examinations: gestational day 0, 6 through 15, 20
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day: 20
- Organs examined: laparohysterectomic examination and necropsy
OTHER:Individual live foetuses were weighed, sexed, and examined for external morphological abnormalities; all live foetuses were examined for visceral malformations; half of the foetal heads were removed, fixed in Bouin's solution, and examined by free hand sectioning of the whole foetal head; all foetal carcasses were double stained with Alcian Blue/Alizarin Red S and examined for skeletal malformation.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: half per litter
Statistics:
see ANY OTHER INFORMATION ON MATERIALS AND METHODS, below.One way analysis of variance (ANOVA). Pairwise comparison with vehicle control (Dunnet, 1964) if ANOVA significant.Kruskal-Wallis test. Pairwise comparison with vehicle control using Mann-Whitney U test if Krustal-Wallis significant (Siegel, 1956).
Historical control data:
Full historical control data given (CD Rat measured at Research Triangle Inst., Research Triangle Park, NC)

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Clinical signs were noted in all substance treated groups, and included pica, piloerection, weight loss, lacrimation, lethargy, rough coat, and chromodacryorrhea. Signs of toxicity were more frequently noted at doses of greater than 10 mg/kg/day.
Dermal irritation (if dermal study):
not examined
Mortality:
not specified
Description (incidence):
one animal at 450 mg/kg/day and five animals at 900 mg/kg/day (three dams that died were pregnant.)
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Maternal body weight did not differ among dose groups on gd 0, or on gd 6. On gd 11, 15 and 20 maternal body weight exhibited a dose-related decrease with the 10 mg/kg/day dose clearly a no effect level, and the 100, 450, and 900 mg/kg/dose groups significantly below controls. Similarly, maternal weight gain during gestation (gd 0-20), maternal weight gain during treatment (gd 6-15) and corrected maternal weight gain exhibited a dose-related decrease with the low dose representing a no effect level, and the 100, 450, and 900 mg/kg/day groups significantly below controls.
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:
effects observed, treatment-related
Description (incidence and severity):
Scopolamine had no significant effect on gravid uterine weight. Absolute maternal liver weight was significantly decreased at the 900 mg/kg/day dose level. Relative maternal liver weight (percent body weight) was slightly but significantly increased at 450 and 900 mg/kg/day.
Gross pathological findings:
not examined
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Number of abortions:
not specified
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
Confirmed-pregnant females did not differ significantly among dose groups with regard to the number of implantation sites per litter, or the percent preimplantation loss
Total litter losses by resorption:
no effects observed
Description (incidence and severity):
The percent resorptions per litter, percent litters with resorptions, percent dead fetuses per litter, percent nonlive (resorptions and dead fetuses) implants per litter, and percent litters with nonlive implants were unaffected by treatment.
Early or late resorptions:
no effects observed
Description (incidence and severity):
see above
Dead fetuses:
no effects observed
Description (incidence and severity):
see above
Changes in pregnancy duration:
not specified
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 specified
Changes in number of pregnant:
no effects observed
Description (incidence and severity):
At scheduled sacrifice, pregnancy was confirmed for 95.8% (23/24), 85.2% (23/27), 100% (28/28), 87.5% (21/24), and 95.5% (21/22) of all animals surviving to gd 20 in the vehicle through high dose groups, respectively.
Other effects:
not specified
Description (incidence and severity):
The number of corpora lutea per dam was slightly but significantly below the control group for dams assigned to the 10 and 900 mg/kg/day groups
Details on maternal toxic effects:
Maternal toxic effects: yes.
Details on maternal toxic effects: At 10 mg/kg bw/day: no effect level for maternal toxicity. At doses greater than or equal to 100 mg/kg bw/day: presence of significant dose related maternal toxicity (reduced maternal body weight and weight gain).At doses greater than or equal to 450 mg/kg bw/day, the presence of significant maternal toxicity was observed. At the doses tested (0, 10, 100, 450 or 900 mg/kg bw/day scopolamine hydrobromide) there was no separation of maternal toxicity from developmental toxicity.

Effect levels (maternal animals)

open allclose all
Dose descriptor:
LOAEL
Effect level:
100 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: >=100 mg/kg bw/day: presence of significant dose related maternal toxicity (reduced maternal body weight and weight gain). >= 450 mg/kg bw/day, the presence of significant maternal toxicity was observed
Dose descriptor:
NOEL
Effect level:
10 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: no effect observed

Results (fetuses)

Fetal body weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
For mean fetal body weight per litter (male, female, and the sexes combined) values for substance treated fetuses in Replicate I were not significantly different from controls at any dose level, although the substance treated groups tended to be lower than controls. In Replicate II, however, mean fetal body weight per litter (sexes combined and female) exhibited an overall treatment effect, with the 100 mg/kg/day dose group, only, significantly below controls. Male fetal body weight per litter was significantly depressed below control in the 100, 450, and 900 mg/kg/day dose groups in Replicate II. Examination of the study records indicates that in the 100 mg/kg/day dose group, fetuses from Replicate II generally had lower body weights than fetuses in Replicate I. In particular, one litter in Replicate II had a mean fetal body weight of 2.73 g, the smallest mean litter weight in the entire study. There was no obvious reason for this occurrence. Therefore, the effect of the substance on fetal body weight was minimal, and was not consistent across replicates.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): effects observed, non-treatment-related
Changes in sex ratio:
no effects observed
External malformations:
effects observed, non-treatment-related
Skeletal malformations:
effects observed, non-treatment-related
Visceral malformations:
effects observed, non-treatment-related
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects: no effects. Details on embryotoxic / teratogenic effects: At 10 mg/kg bw/day: no effect level for developmental toxicity. At doses greater than or equal to 100 mg/kg bw/day: a marginal non-dose related reduction in fetal body weight, and a marginal non-dose related increase in the incidence of malfunctions per litter. At doses greater than or equal to 450 mg/kg bw/day, exposure to scopolamine hydrobromide was associated with a significant increase in the incidence of short ribs. At the doses tested (0, 10, 100, 450, or 900 mg/kg bw/day) there was no separation of maternal toxicity from developmental toxicity.

Effect levels (fetuses)

open allclose all
Key result
Dose descriptor:
NOAEL
Effect level:
900 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: >= 100 mg/kg bw/day: non-dose related reduction in fetal body weight, and non-dose related increase in the incidence of malfunctions per litter. >= 450 mg/kg bw/day, was associated with a significant increase in the incidence of short ribs.
Remarks on result:
other: there was no separation of maternal toxicity from developmental toxicity
Dose descriptor:
NOEL
Effect level:
10 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no adverse effect observed

Overall developmental toxicity

Developmental effects observed:
yes
Lowest effective dose / conc.:
100 mg/kg bw/day (nominal)
Treatment related:
no
Relation to maternal toxicity:
not specified
Dose response relationship:
not specified
Relevant for humans:
not specified

Any other information on results incl. tables

Maternal mortality

Dose (mg/kg bw/day)       

No. of Dead

0                                                  

0

10                                          

0

100                                        

0

450                                        

1

900                                        

5

Number pregnant per dose level

Dose (mg/kg/day)       

No. of Pregnant

0                                                

23/30

10                                 

23/28

100                               

28/28

450                            

21/25

900                               

21/30

Number dams removed

Dose (mg/kg bw/day)       

No. dams removed

0                                   

6/30

10                                 

1/28

100                              

0/28

450                               

0/25

900                            

3/30

Resorptions per litter (reported as mean +- standard error of the mean):

Dose (mg/kg bw/day)       

Resorptions per Litter SD

0                                   

0.52 +-0.16

10                            

1.00 +-0.61

100                            

0.89 +-0.18

450                            

0.52 +-0.18

900                            

1.62 +-0.84              

Number of implantations (reported as mean +- standard error of the mean):

Dose (mg/kg bw/day)       

Implantation Sites per Litter

0                                   

13.87 +-0.32

10                                 

13.30 +-0.30

100                               

13.46 +-0.38

450                               

13.10 +-0.62

900                            

13.33 +-0.28

Pre-implantation Loss (reported as mean +- standard error of the mean):

Dose (mg/kg bw/day)       

Pre-implantation Loss

0                                  

4.15 +-1.67

10                                 

2.21 +-1.24

100                            

3.44 +-1.16

450                            

4.17 +-3.74

900                               

2.67 +-1.45

Number of corpora lutea per dam (reported as mean +- standard error of the mean):

Dose (mg/kg bw/day)       

No. corpora lutea per dam

0                                   

13.90 +-0.40

10                                 

12.13 +-0.70

100                               

13.21 +-0.41

450                               

12.67 +-0.35

900                               

11.95 +-0.85

Duration of Pregnancy: 20 days

Body weight:

Maternal body weight did not differ among dose groups on gestational day (gd) 0, the day of assignment to the study, or on gestational day 6, the first day of dosing. On gestational day 11, 15 and 20 maternal body weight exhibited a dose-related decrease with the 10 mg/kg bw/day dose clearly a no effect level, and the 100, 450, and 900 mg/kg bw/day dose groups significantly below controls.

Maternal body weight (gestational day 20) (reported as mean +- standard error of the mean):

Dose (mg/kg bw/day)       

Maternal Body weight

0                                   

358.87       +-4.27

10                                 

345.38       +-6.64

100                               

333.54       +-4.45

450                               

326.80       +-5.11

900                            

318.24       +-7.15

Description of clinical signs

Clinical signs of toxicity were noted in all scopolamine hydrobromide-treated groups, and included pica, piloerection, weight loss, lacrimination, lethargy, rough coat, and chromodacryorrhea. Rudimentary ribs.

Applicant's summary and conclusion

Conclusions:
Exposure of timed-pregnant CD rats to Scopolamine hydrobromide trihydrate at doses up to 900 mg/kg bw/day on gestational days 6 - 15 caused no clear evidence of teratogenic response in gestation day 20 rat foetuses. Marginal evidence of intrauterine growth retardation and a non-dose-related trend toward an increase in the incidence of malformations was observed only at doses that caused significant maternal toxicity.