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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
12/08/1997 to 02/10/1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study was conducted according to a protocol that is similar to the appropriate OECD test guideline, with acceptable restrictions. The restrictions were that only duplicate plates were used.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
other: "Standards for Mutagenicity Tests using Microorganisms" (Notification No. 77, Ministry of Labour, Japan, September 1, 1988
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Only duplicate plates tested
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
439-510-7
EC Name:
-
Cas Number:
149048-48-6
Molecular formula:
Constituent 1: C14H26N2O3Si Constituent 2: C13H22N2O2Si
IUPAC Name:
Reaction Mass of N-[3-(trimethoxysilyl)propyl]-1,3-benzenedimethanamine and {3-[(2,2-dimethoxy-1,2-azasilolidin-1-yl)methyl]phenyl}methanamine
Test material form:
liquid

Method

Target gene:
Histidine (Salmonella strains) and tryptophan (E. coli strain)

Base-pair substitution type: Salmonella typhimurium TA100, TA1535, and Escherichia coli WP2 uvrA.
Frame-shift type: Salmonella typhimurium TA98, TA1537.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not applicable
Species / strain / cell type:
E. coli WP2 uvr A
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
phenobarbital and 5,6-benzoflavene induced rat
Test concentrations with justification for top dose:
1.2, 4.9, 20, 78, 313, 1250 and 5000 µg/plate
Vehicle / solvent:
Test substance
- Vehicle(s)/solvent(s) used: DMSO.
- Justification for choice of solvent/vehicle: None given.

Positive controls
- AF-2, ICR-191, 2AA and B[a]P: DMSO.
- sodium azide: distilled water.
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2)
Remarks:
-MA: TA 100, WP2 uvrA - 0.01 µg/plate; TA 98 - 0.1 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
-MA: TA 1535 - 0.5 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Methoxy-6-chloro-9-[3-(2-chloroethyl)aminopropylamino]acridine·2HCl (ICR-191)
Remarks:
-MA: TA 1537 - 1.0 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
+MA: TA 1535 - 2.0 µg/plate; WP2 uvrA - 10.0 µg/plate
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
yes
Positive controls:
no
Positive control substance:
benzo(a)pyrene
Remarks:
+MA: TA 100, TA 98, TA 1537 - 5.0 µg/plate
Details on test system and experimental conditions:
ACTIVATION:
Composition of S9 mix (per 1 ml):
Water: 0.9 mL
S9: 0.1 mL
MgCl2: 8.0 µmol
KCl: 33.0 µmol
G-6-P: 5.0 µmol
NADPH: 4.0 µmol
NADH: 4.0 µmol
Na-phosphate buffer (pH 7.4): 100.0 µmol

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes at 37°C
- Exposure duration: 48 hours at 37°C

SELECTION AGENT (mutation assays): minimal glucose agar

NUMBER OF REPLICATIONS: duplicate plates. An initial dose range-finding study was followed by two further independent experiments.

DETERMINATION OF CYTOTOXICITY: reduction in number of revertant colonies
Evaluation criteria:
If the number of revertant colonies on the test plates increased significantly in comparison with that on the control plates (based on twice as many as that of the negative control), and dose-response and reproducibility were also observed, the test substance was judged to be positive.
Statistics:
No statistical analysis done.

Results and discussion

Test results
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING STUDY: Growth inhibition was determined for seven concentrations of test substance: 1.2, 4.9, 20, 78, 313, 1250 and 5000 µg/plate.

Growth inhibition was observed as follows:
≥4.9 µg/plate for TA1537 without S9.
≥20 µg/plate for TA100, TA1535 and TA98 without S9.
≥78 µg/plate for E.coli WP2 uvrA without metabolic activation.

Hence, the highest concentrations of test substance used in the main test were as follows:

S. typhimurium TA1537 without S9: 4.9 µg/plate.
S. typhimurium TA100, TA1535, TA98 without S9: 20 µg/plate.
E. coli WP2 uvrA without S9: 78g µg/plate.
All S. typhimurium strains with S9: 313 µg/plate.
E. coli WP2 uvrA with S9: 1250 µg/plate.

Remarks on result:
other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:
The submission substance has been tested for mutagenicity to bacteria in a study conducted according to a protocol that is similar to OECD 471. No evidence for a test substance induced increase in the number of revertants was observed when tested up to cytotoxic concentrations with and without metabolic activation in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 using the preincubation method in the initial and the repeat experiment. Appropriate positive and solvent controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity under the conditions of the test.

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