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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
From 29 February 1996 to 1 April 1996
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Similar to guideline, but only two bacterial strains tested

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
only two bacterial strains tested
GLP compliance:
not specified
Type of assay:
bacterial gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
Histidine
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 100
Details on mammalian cell type (if applicable):
contains a histidine missense mutation but is also deficient in a DNA repair system and has a defective lipopolysaccharide coat on the cell wall
Species / strain / cell type:
S. typhimurium TA 98
Details on mammalian cell type (if applicable):
contains a histidine frameshift mutation. Again it has a definitive DNA repair system and lipopolysaccharide coat
Metabolic activation:
with and without
Metabolic activation system:
Liver extract from Aroclor 1254-induced male Sprague-Dawley rats
Test concentrations with justification for top dose:
A solution of the substance was prepared in ethanol at 5 mg/mL, and four half-log dilutions were prepared from this solution. Aliquots (0.1mL) of each concentration of the substance were placed in sterile tubes.
Test material (µg per plate): 2500 (sterility check), 5000, 500, 50, 5, 2500, 250, 25, 2.5, 0, 0 (0.2 mL solvent).
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
in both strains with and without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
in TA100 without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
in TA98 without metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at 500 µg and above
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:
cytotoxicity
Remarks:
at 500 µg and above
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Standard tests for bacterial sensitivity:

   TA100  TA98
 2-Aminofluorene (10µg/plate) with activation  +  +
  9-Aminoacridine (80µg/plate) non-activated  -  -
  Sodium azide (2µg/plate) non-activated  +  -
  Ampicillin (8mg/mL in purified water)  Resistant  Resistant

+ Increased reversion (his - to his +) over solvent controls

- No increase in reversion

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test material did not exhibit any mutagenic activity under the conditions of test.
Executive summary:

The material was examined for mutagenic activity in two histidine-dependent auxotrophs of Salmonella typhimurium, strains TA 98 and TA 100, using plate-incorporation assays.

The studies, which were conducted in the presence and absence of an activiting system derived from rat liver (S-9 mix), employed a range of levels of the substance from 5 to 500 µg per plate, selected following a preliminary toxicity test in strain TA 98. The test included solvent (ethanol) controls with and without S-9 mix.

The substance did not exhibit any mutagenic activity under the conditions of test. Positive controls were effective, such indicating the validity of the test system.