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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:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study very similar to OECD 471 with no deviations. Study well documented. Klimisch 2.c study, comparable to a guideline study with acceptable restrictions.

Data source

Reference
Reference Type:
publication
Title:
Assay of 855 test chemicals in ten tester strains using a new modification of the ames test for bacterial mutagens
Author:
McMahon R.E., Cline J.C. and Thompson C.Z.
Year:
1979
Bibliographic source:
Cancer research, 39, 682-693.

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
No data

Method

Target gene:
Histidine, gal-bio-uvrB, LPS were the target genes for the Salmonella typhimurium strains used and the tryptophan gene was the target gene in the Escherischia coli strains used.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Species / strain / cell type:
E. coli WP2
Species / strain / cell type:
E. coli WP2 uvr A
Species / strain / cell type:
bacteria, other: S. typhimurium G46, C3076, D3052
Metabolic activation:
with and without
Metabolic activation system:
S9 mix freshly prepared
Test concentrations with justification for top dose:
The test concentrations range from 0.1 to 1000 µg/mL. No further data are available
Vehicle / solvent:
- Vehicle(s)/solvent(s) no data
No further data
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
not specified
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: streptozotocin
Remarks:
without S-9 mix
Untreated negative controls:
yes
Negative solvent / vehicle controls:
not specified
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
2-acetylaminofluorene
Remarks:
with S-9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar, plate incorporation with a gradient plate technique

DURATION
- Exposure duration: 48 hours


NUMBER OF REPLICATIONS: six to eight


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

No further data
Evaluation criteria:
In the gradient technique, the concentration range over which chemically induced mutant colonies are present is recorded. The minimal inhibitory concentration is observed as a clear zone in the agar gel. This level is a basis for the expert to judge on the mutagenicity potential of the test substance compared with positive controls.
It is assumed then than all substances showing no revertants over 1000 µg/mL or to the concentration showing first sign of toxicity are considered as negative in this test.
Statistics:
No data

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
bacteria, other: S. typhimurium G46, C3076, D3052
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No data
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The authors tested the mutagenicity potential of benzoyl chloride with a methodology similar to the OECD guideline 471. In the test conditions, benzoyl chloride was found negative. Therefore, benzoyl chloride should not be considered as a potent mutagen in in vitro bacterial systems.
Executive summary:

The authors tested the mutagenicity potential of benzoyl chloride (CAS n° 98 -88 -4) with a methodology similar to the OECD guideline 471, with the recommended strains of salmonella typhimurium and E. coli. They conducted this test with a slightly modified protocol proposed by Ames for the plate incorporation. They did a gradient technique for the plate incorporation allowing to test a full range of concentration ranging from 0.1 µg/mL to 1000 µg/mL or to cytotoxic concentrations. They included also in this test four other strains of S. typhimurium to cover all major kind of mutations. All strains were tested with and without metabolic activation and positive and negative controls were included in the experiment.

With this gradient technique, the concentration range over which chemically induced mutant colonies are present is recorded. The minimal inhibitory concentration is observed as a clear zone in the agar gel. This level is a basis for the expert to judge on the mutagenicity potential of the test substance compared with positive controls. It is assumed then that all substances showing no revertants over 1000 µg/mL or to the concentration showing first sign of toxicity are considered as negative in this test. Besides a complementary analysis on the number of revertants may be undergone to confirm the expertise.

According to the authors, this test was negative for benzoyl chloride for all strains. Even if this test system requires an expert judgement, we could assume that this test is enough robust and sensitive to detect mutagen. And since all strains returned negative, benzoyl chloride should not be considered as a potent mutagen in in vitro bacterial systems.

The GLP status of this study is unknown but the methodology used was very similar to the OECD guideline 471. Since no deviations were observed regarding the guideline requirements and as it is well documented. This study should be considered as reliable with restrictions, a Klimisch 2.c study, comparable to a guideline study with accpetable restrictions.