Registration Dossier

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
The mutagenic potential of m-trifluoromethylphenylisocyanate was examined in the Salmonella/microsome test. Bacteria of four histidine auxotrophic Salmonella typhimurium LT2 mutant strains (TA 98, TA 100, TA 102, TA 1535, and TA 1537) were exposed to doses up to 5000 pg per plate. Both the plate incorporation method and the preincubation method was used.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
content: > 99.3 %

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Additional strain / cell type characteristics:
other: Firstly, they are deep rough since certain lipopolysaccharide side chains are missing in the bacterial cell wall. Secondly, with the exception of TA 102, all strains have reduced capability to repair DNA-damage
Metabolic activation:
with and without
Metabolic activation system:
S-9 mix
Test concentrations with justification for top dose:
Plate incorporation method: up to 5 µl/plate;
Preincubation method: up to 5 µl/plate
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: sodium azide, anthracene-2-amine, cumene hydroperoxide, mitomycin C, 2-nitro-9H-fluorene, 4-nitro-o-phenylenediamine

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
In the plate incorporation test doses of up to and including 0.009 µl per plate did not cause any bacteriotoxic effects. In the preincubation test doses of up to and including 0.001 µl per plate did not cause any bacteriotoxic effects
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Precipitation was observed at the highest tested dose of 5 µl/plate.

In the plate incorporation test doses of up to and including 0.009 µl per plate did not cause any bacteriotoxic effects. At higher doses, the test item had a strain-specific bacteriotoxic effect. Due to this effect this range could not be used up to 5 µl per plate for assessment purposes.

In the preincubation test doses of up to and including 0.001 µl per plate did not cause any bacteriotoxic effects. At higher doses, the test item had a strain-specific bacteriotoxic effect. Due to this effect this range could not be used up to 5 µl per plate for assessment purposes.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative
Executive summary:

The test item (m-trifluoromethylphenylisocyanate) was initially investigated using the Salmonella/microsome plate incorporation test for point mutagenic effects in doses of up to and including 5 µl per plate on five Salmonella typhimurium LT2 mutants. These comprised the histidine-auxotrophic strains TA 1535, TA 100, TA 1537, TA 98 and TA 102. The independent repeat was performed as preincubation for 60 minutes at 37°C. Other conditions remained unchanged.

Precipitation was observed at the highest tested dose of 5 µl/plate.

In the plate incorporation test doses of up to and including 0.009 µl per plate did not cause any bacteriotoxic effects. At higher doses, the test item had a strain-specific bacteriotoxic effect. Due to this effect this range could not be used up to 5 µl per plate for assessment purposes.

In the preincubation test doses of up to and including 0.001 µl per plate did not cause any bacteriotoxic effects. At higher doses, the test item had a strain-specific bacteriotoxic effect. Due to this effect this range could not be used up to 5 µl per plate for assessment purposes.

Evidence of mutagenic activity of the test item was not seen. No biologically relevant increase in the mutant count, in comparison with the negative controls, was observed up to assessable doses.

The positive controls sodium azide, anthracene 2 amine, cumene hydroperoxide, mitomycin C, 2 nitro-9H-fluorene and 4 nitro o phenylenediamine showed the ex-pected mutagenic effect, as was seen by a biologically relevant increase in mutant colonies compared to the corresponding negative controls.

Therefore, the test item was negative without and with S9 mix in the plate incorporation as well as in the preincubation modification of the Salmonella/microsome test.