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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: 51 % w/w solution in water, stabilized with X % NaOH
Details on test material:
- Substance type: Liquid
- Physical state: Light brown liquid
- Molecular formula (if other than submission substance): C8H18NaO2PS2
- Molecular weight (if other than submission substance): 264
- Smiles notation (if other than submission substance): CC(C)COP(=S)([S-])OCC(C)C.[Na+]
- InChl (if other than submission substance): InChI=1/C8H19O2PS2.Na/c1-7(2)5-9-11(12,13)10-6-8(3)4;/h7-8H,5-6H2,1-4H3,(H,12,13);/q;+1/p-1

Method

Target gene:
HPRT locus. This gene is situated in man, hamster and other species at the X-chromosome. The gene product, hypoxanthine guanine phosphoribosyl transferase, an enzyme which is not vital for the cell, activates the purine analogues 8-azaguanine and 6-thioguanine (used in this assay) to toxic metabolites. Mutants which do not synthesize the active enzyme are resistant to high concentrations of 6-thioguanine or 8-azaguanine. Such mutants can be obtained by several types of mutations since a simple destruction of a gene ('forward mutation') is sufficient.
Species / strain
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Details on mammalian cell type (if applicable):
- Type and identity of media: Dulbecco's modified Eagle-Medium supplemented with 10% fetal calf serum2, penicillin2 (100 U/mL) and streptomycin2 (100 µg/mL) called DMEM-FCS. Cultures are incubated at 37°C in a humidified atmosphere (90%) containing 10% CO2. For subculturing, a trypsin (0.05%)-EDTA (ethylene¬diamine¬tetra¬acetic acid, 0.02%) solution in modified Puck's salt solution A2 is used. Exposure to the test item in the presence of S9 mix is performed in Dulbecco's phosphate buffered saline (PBS)2 which additionally contained 20 mM HEPES (N'-2-hydroxyethylpiperazine-N'-2-ethane-sulfonic acid)2 pH 7.4 (PBS-HEPES). The cells are periodically checked for the absence of mycoplasma contamination by using the HOECHST stain 33258. The spontaneous mutation rate is continuously monitored.
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: yes/no
- Periodically "cleansed" against high spontaneous background: yes
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
a microsomal preparation derived from Aroclor 1254-induced rat liver.
Test concentrations with justification for top dose:
Preliminary study: 10, 25, 100, 250, 1000, 2500 and 5000 μg IBP1-Na/mL
Main study: (4h) 156.3, 312.5, 625, 1250, 2500 μg IBP1-Na/mL. (24h) 78.13, 156.3, 312.5, 625, 1250 μg IBP1-Na/mL.
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
benzo(a)pyrene

Results and discussion

Test results
Key result
Species / strain:
Chinese hamster lung fibroblasts (V79)
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:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results:
negative with metabolic activation
negative without metabolic activation

Under the present test conditions the test substance, IBP1-Na, tested up to a cytotoxic concentration, caused no mutagenic effect in the Chinese hamster lung fibroblasts (V79) carried out without and with metabolic activation.
Remark: The test solution contains NaOH due to the production method.