Hyoscine

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

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 with acceptable restrictions

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:

Chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells: Evalutions of 108 chemicals.

Author:

Galloway, S. M. et al.

Year:

1987

Bibliographic source:

Environ. Mol. Mutagen. 10 (Suppl. 10), 1-175

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

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: 102%+-0.6% (functional group titration)

Method

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

-S9: 1000, 1600, 3000 µg/mL
+S9: 1600, 3000, 5000 µg/mL

Vehicle / solvent:

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

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

cyclophosphamide

mitomycin C

Details on test system and experimental conditions:

DURATION
- Exposure duration:
- without S9: treatment time 10.5 hr; when after the addition of Colcemid: incubation time 2 hr
- with S9: treatment time 2 hr; when change of medium; incubation time 11 to 11.5 hr with Colcemid present in the final 2 hr
SPINDLE INHIBITOR (cytogenetic assays): Colcemid
STAIN (for cytogenetic assays): GiemsaIn the aberration test without S9, cells were incubated in McCoy's 5A medium with scopolamine hydrobromide trihydrate for 10.5 hours; Colcemid was added and incubation continued for 2 hours. The cells were then harvested by mitotic shake-off, fixed, and stained with Giemsa. For the Aberration with S9, cells were treated with scopolamine hydrobromide trihydrate and S9 for 2 hours, after which the treatment medium was removed and the cells were incubated for 11 to 11.5 hours in fresh medium, with Colcemid present for the final 2 hours. Cells were harvested in the same manner as for the treatment without S9. As an alteration in pH was observed in the first trial conducted with S9 and the second trial with S9 was conducted with HEPES buffer present in the medium to stabilize pH.
NUMBER OF CELLS EVALUATED: 200 first-division metaphase cells were scored at each dose level

Statistics:

To arrive at a statistical call for a trial, analyses were conducted on both the dose response curve and individual dose points. For a single trial, a statistically significant (P<=0.05) difference for one dose point and a significant trend (P<=0.015) were considered weak evidence for a positive response; significant differences for two or more doses indicated the trial was positive. A positive trend test in the absence of a statistically significant increase at any one dose resulted in an equivocal call.

Results and discussion

Test results

Test results 1

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

the high dose was limited by toxicity in the trials conducted without S9

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

with S9, no toxicity was noted and 5 mg/mL was selected as the high dose

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Induction of Chromosomal Aberration in Chinese Hamster Ovary Cells by Scopolaminehydrobromide Trihydrate

 

	Dose (µg/mL)	Total Cells	No. of Abs	Abs/Cell	Cells with Abs (%)		Dose (µg/mL)	Total Cells	No. of Abs	Abs/Cell	Cell with Abs (%)
	-S9						+S9
DMSO		200	2	0.01	1.0	DMSO		200	1	0.01	0.5
Mitomycin C	0.0625	200	40	0.20	16.0	Cyclo- phosphamide	2.5	200	35	0.18	15.0
	0.2500	50	17	0.34	30.0		7.5	50	23	0.46	36.0
Scopolamine-hydrobromidetrihydrate	1000	200	1	0.01	0.5	Scopolamine-hydrobromidetrihydrate(Trial 1)	1600	200	3	0.02	1.5
	1600	200	2	0.01	1.0		3000	200	2	0.01	1.0
	3000	200	1	0.01	0.5		5000	200	12	0.06	6.0
					P=0.655						P<0.001
						(Trial 2) DMSO		200	1	0.01	0.5
						Cyclophosphamide	2.5	200	28	0.14	12.0
							7.5	50	17	0.34	34
						Scopolamine-hydrobromide trihydrate (Trial 2)	1600	200	3	0.02	1.5
							3000	200	2	0.01	1.0
							5000	200	28	0.14	11.0
											P<0.001

Applicant's summary and conclusion

Conclusions:

Positive with metabolic activation. Induction of chromosome aberration was observed in cultured CHO cells in the presence of S9 metabolic activation in each of two trials at the highest dose tested (5000 µg/mL).

Executive summary:

The present study determined the mutagenicity of Scopolamine hydrobomide trihydrate according to a well-described method which is similar to a current internationally established guidelines (OECD 473). The effects were analysed using the Chinese hamster ovary cells with or without S9 mix (from Sprague Dawley rat liver). The study was part of the National Toxicology Program (NTP) of the U.S. Department of Health and Human Services and reviewed and showed that the test item has mutagenic properties under conditions of metabolic activation.