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Toxicological information

Genetic toxicity: in vitro

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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

Data source

Referenceopen allclose all

Reference Type:
secondary source
Title:
Unnamed
Year:
1997
Report date:
1997
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

Constituent 1
Chemical structure
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 resultsopen allclose all
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
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.