Hyoscine

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

In accordance with column 2 of REACH Annex VIII, screening test for reproductive/developmental toxicity does not need to be conducted as pre-natal developmental toxicity studies are available.

In the key repeated dose toxicity study (14 weeks in rat, NTP (1997)), sperm morphology and vaginal cytology parameters were examined and no effects were observed up to the highest concentration tested ( 1,200 mg/kg bw).

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Effects on developmental toxicity

Description of key information

For the read-across substance Scopolamine hydrobromide trihydrate, embryotoxic effects in rats and mice were observed only at maternally toxic doses. Generally, no teratogenic effects were observed in these reliable studies in mice and rats, but malformations were observed in a Klimisch 4 study with intraperitoneal administration of Scopolamine in mice.

 

Link to relevant study records

Reference

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

Justification for type of information:

The read-across justification is included as attachmant to Iuclid section 13.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Details on test animals or test system 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

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

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.

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)

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

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.

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

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.

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

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

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.

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.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

900 mg/kg bw/day

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

One reliable pre-natal developmental toxicity study conducted with the read-across substance Scopolamine hydrobromide trihydrate in mice and one reliable study in rats with the read-across substance are available (both NTP studies, 1987). For both studies a NOAEL of 900 mg/kg bw/day was determined for teratogenicity.

The study conducted with rats was selected as key study, as according to the ECHA guideline R.7a, the preferred rodent species for reproductive toxicity is the rat. This key study was an oral (gavage) study conducted in a manner similar to OECD 414. The study identified a maternal LOAEL of >=100 mg/kg bw/day and teratogenicity NOAEL of 900 mg/kg bw/day. At doses of 900 mg/kg bw/day no untoward effects without maternal toxicity was observed. A NOEL of 10 mg/kg bw/day was observed, for both, maternal and developmental toxicity. The other NTP study, conducted with mice, also an oral (gavage) study, was selected as supporting study. In this study, doses up to 900 mg/kg bw/day had no adverse effect on prenatal viability, produced no evidence of teratogenesis, and caused only a marginal reduction in fetal body weight at doses of 450 and 900 mg/kg bw/day that also caused marginal maternal toxicity. The NOEL of this study was 100 mg/kg bw/day.

The results of this both available pre-natal studies (in mice and rats, respectively) were dissimilar in that the rats did not tolerate the substance very well and the number of rudimentary ribs increased. However, the effect is not generally considered a toxic effect because rats have a normal high background rate for developing the extra rib. Furthermore, historical records have indicated that stresses on the female parent like chemical exposure can induce the animal to develop these extra ribs.

One further supporting study conducted with mice is available (Yu, 1988). In this study, after intraperitoneal administration of Scopolamine (4.6 and 59 µg), incidences of malformed fetuses of 3.8% and 8.2%, respectively, were observed. This study was scored with Klimisch 4, based on insufficient documentation and was not used for hazard assessment. Furthermore, the background of this study was the preliminarily screening of Scopolamine, used as drug (intravenous anesthetic), regarding teratogenicity. For this, intraperitoneal administration was selected as test route. Under REACH, it is specified that the reproductive toxicity studies should be conducted via the “most appropriate route of administration, having regard to the likely route of human exposure”. “Likely routes of human exposure” within REACH are oral, inhalation and dermal (ECHA guideline R.7a, 2016). According to the test methods for reproductive toxicity which focus on the detection of reproductive hazards, the oral route (gavage, in diet, or in drinking water) is the “default” route, except for gases. Using parenteral administration (e.g. intraperitoneal), the substance will not subjected to the first-pass effect and thus the substance will not be absorbed from the gastrointestinal tract and do not undergo metabolism in the liver. After oral administration, the first pass through the liver greatly reduces the bioavailability of the substance and thus, the effects after intraperitoneal administration can be more severe than after oral administration. But more importantly, the doses given were 1/10 and 1/50th of the LD 50. Generally the LD50 is determined by a single application and observe the animal for several days. This study does not state if their LD50 was via the same intraperitoneal injection. Furthermore, given the animals 10 consecutive dosages (days 6 to 16) both doses came close to the total LD 50 value amount. No other signs about overall toxicity were given but looking at the females’ growth for the low and high application the growth rates were similar to the positive control females. These mice were highly stressed toxicologically and a survival mechanism is to abort the fetus in order for the female to survive. So a finding of this nature would be expected when the dams are given such high doses especially via the intraperitoneal route. The intent of a teratogenicity study is minimizing the extent of toxicity to the females to see what the compound does to the fetus alone. The doses given should have produced no more than 10% effects on the dams and not nearly 100% as listed in this study.

In conclusion, for the read-across substance Scopolamine hydrobromide trihydrate, embryotoxic effects in rats and mice were observed only at maternally toxic doses (both NTP, 1987). Generally, no teratogenic effects were observed in these reliable studies in mice and rats, but malformations were observed in a Klimisch 4 study (Yu, 1988) with intraperitoneal administration of Scopolamine in mice.

Justification for classification or non-classification

Based on the available data, the substance will not be classified.