Hyoscine

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 March 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Justification for type of information:

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

Data source

Reference

Reference 1

Reference Type:

secondary source

Title:

Unnamed

Year:

1997

Report date:

1997

Reference 2

Reference Type:

publication

Title:

A simple fluorescent staining procedure for micronuclei and RNA in erythrocytes using Hoechst 33258 and pyronin Y

Author:

James T. Mac Gregor et al

Year:

1983

Bibliographic source:

Mutation Research, 120, 269-275

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Principles of method if other than guideline:

- repeated exposure over 14 weeks

GLP compliance:

no

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Hyoscine hydrobromide trihydrate

Cas Number:

6533-68-2

Molecular formula:

C17 H21 N O4 . Br H . 3 H2 O

IUPAC Name:

Hyoscine hydrobromide trihydrate

Test material form:

solid: particulate/powder

Details on test material:

- Analytical purity: 101.7%+-0.6% (functional group titration), equivalent to 89.2%+-0.5% (anhydrous scopolamine hydrobromide) and 11.2%+-0.2% water (Karl Fischer)
- Impurities (identity and concentrations): 0.2% Impurities
- Lot/batch No.: 283- Supplier: Henley and Company, Inc. (New York, NY)

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Simonsen Laboratories, Inc. (Gilroy, CA)- Age at study initiation: 6 or 7 weeks
- Housing: mouse were housed individually
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
ENVIRONMENTAL CONDITIONS
- Temperature: 20 to 24.9°C- Humidity: 45% to 71%
- Air changes (per hr): min. 10 changes per hour- Photoperiod (hrs dark / hrs light): 12/12 dark/light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:0, 15, 45, 135, 400 or 1200 mg scopolamine hydrobromide trihydrate/kg body weight in distilled water by gavage for 14 weeks

Duration of treatment / exposure:

repeated exposure 14 weeks

Frequency of treatment:

repeated exposure 14 weeks

Doses / concentrations

Remarks:

Doses / Concentrations:0, 15, 45, 135, 400 or 1200 mg/kg bwBasis:nominal conc.

No. of animals per sex per dose:

10 male and 10 female mice

Control animals:

yes, concurrent vehicle

Positive control(s):

none

Examinations

Tissues and cell types examined:

Blood

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Peripheral blood samples were obtained from male and female B6C3F1 mice at the end of the 14 week toxicity study.DETAILS OF SLIDE PREPARATION: Smears were immediately prepared and fixed in absolute methanol, stained with a chromatin- specific fluorescent dye mixture of Hoechst 33258/pyronin Y (MacGregor et al., 1983).METHOD OF ANALYSIS: Slides were scanned at 630 or 1000x magnification with a semi-automated image analysis system to determine the frequency of micronuclei in 10000 normochromatic erythrocytes (NCEs) in each of 10 animals per dose group.

Evaluation criteria:

In the micronucleus test an individual trial was considered positive if the trend test P value was less than or equal to 0.025 or the P value for any single exposure group was less than or equal to 0.025 divided by the number of exposure groups.

Statistics:

Testing for increasing trend over exposure groups: one-tailed Cochran-Armitage trend test, followed by pairwise comparisons between each exposure group and the control group

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

not specified

Any other information on results incl. tables

Frequency of Micronuclei in Mouse Peripheral Blood Erythrocytes Following Treatment with Scopolamine Hydrobromide Trihydrate by Gavage for 14 weeks^a

	Dose (mg/kg)	Micronucleated NCEs/1000 Cells^b	Number of Mice
Male
	0	1.95 +-0.14	10
	15	2.12 +-0.06	10
	45	2.18 +-0.20	10
	135	2.22 +-0.12	10
	400	1.91 +-0.21	10
	1200	2.24 +-0.21	10
Trend test		P=0.714^c
Female
	0	1.59 +-0.09	10
	15	1.43 +-0.11	10
	45	1.64 +-0.14	10
	135	1.43 +-0.09	10
	400	1.40 +-0.12	10
	1200	1.38 +-0.12	10
Trend test		P=0.1219

a The detailed scoring protocol is presented by Mac Gregor et al. (1990); 10000 NCEs scored per animal

b Data presented as mean +- standard error of the mean. NCE = normochromatic erythrocyte

c Significance of micronucleated NCEs determined by a one-tailed Cochran-Armitage trend test

Applicant's summary and conclusion

Conclusions:

No increase in the frequency of micronucleated NCEs was noted in peripheral blood samples obtained from male and female mice at the termination of the 14-week toxicity studies with scopolamine hydrobromide trihydrate up to a concentration of 1200 µg/kg bw.