Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Specific details on test material used for the study:
Identification: Tungstosilicic-acid
Batch: MKBR8664V
Purity: >99.9%
Physical state/Appearance: White crystalline solid
Expiry Date: 11 February 2016
Storage Conditions: Room temperature over silica gel in the dark

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 Microsomal fraction
Test concentrations with justification for top dose:
Plate incorporation method: 1.5, 5, 15, 50, 150, 500, 1500 and 5000 μg/plate. The top dose is the maximum recommended by the guideline. Pre-incubation method: 15, 50, 150, 500, 1500 and 5000 μg/plate. The top dose is the maximum recommended by the guideline.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water and 12.5mg/mL polyethylene glycol (PEG).
- Justification for choice of solvent/vehicle: Water is an inert solvent. PEG was used in order to overcome problems with the test substance preventing setting of the Agar to a gel. The PEG helped overcome the setting problem.
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
9-aminoacridine
N-ethyl-N-nitro-N-nitrosoguanidine
benzo(a)pyrene
other: 2-aminoanthracene
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) and pre-incubation methods

DURATION - plate incorporation method
- incubation conditions: 37 °C± 3 °C
- Exposure duration: 48 hours
DURATION - pre-incubation method
- Preincubation period: 7 °C± 3 °C for 20 minutes (with shaking) prior to addition of 2 mL of molten amino-acid supplemented media and subsequent plating onto Vogel-Bonner plates.

NUMBER OF REPLICATIONS: 3

- OTHER: Evaluation method: automated colony counting system.
Evaluation criteria:
1. A dose-related increase in mutant frequency over the dose range tested (De Serres and Shelby, 1979).
2. A reproducible increase at one or more concentrations.
3. Biological relevance against in-house historical control ranges.
4. Statistical analysis of data as determined by UKEMS (Mahon et al., 1989).
5. Fold increase greater than two times the concurrent solvent control for any tester strain (especially if accompanied by an out-of-historical range response (Cariello and Piegorsch, 1996)).
A test item will be considered non-mutagenic (negative) in the test system if the above criteria are not met.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Not mutagenic
Executive summary:

In a guideline GLP Ames reverse bacterial mutation study, the substance tungstosilicic acid was found to be not mutagenic in the 5 strains tested (S typhimurium TA98, TA100, TA1535, TA1537 and E coli WP2uvrA.)