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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Study is well documented but not according GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
R97-0491 Ames BN, McCann J, Yamasaki E. Methods for detecting carcinogens and
mutagens with the salmonella/mammalian-microsome mutagenicity test.
Mutat Res 1975; 31:347-364.
R99-2379 Gee P, Sommers CH, Melick AS, Gidrol XM, Todd MD, Burris RB, et al.
Comparison of responses of base-specific Salmonella tester strains with the
traditional strains for identifying mutagens: the results of a validation study.
Mutat Res 1998; 412:115-130.
R04-0638 Flueckiger-Isler S, Baumeister M, Braun K, Gervais V, Hasler-Nguyen N,
Reimann R, et al. Assessment of the performance of the Ames II assay: a
collaborative study with 19 coded compounds. Mutat Res Genet Toxicol
Environ Mutagen 2004; 558:181-197.
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
other: TA 7001, TA 7002, TA 7003, TA 7004, TA 7005, TA 7006 and TA 98
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Test concentrations with justification for top dose:
CD 713 TD was dissolved in dimethylsulfoxide DMSO (negative control). The highest test concentration 5000 μg/mL was not soluble in DMSO.
Therefore, 7 concentration levels from 1 to 2500 μg/mL were tested along with the appropriate negative and positive controls.
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
2-nitrofluorene
other: 2-aminoanthracene

Results and discussion

Test results
Species / strain:
other: TA 7001, TA 7002, TA 7003, TA 7004, TA 7005, TA 7006 and TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Remarks:
no bacteriotoxicity up to the highest soluble concentration of 2500 μg/mL
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'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Based on the described results it is concluded, that CD 713 TD, when tested up to insoluble concentrations, caused neither base-pair substitutions
nor frameshift mutations in bacteria. No evidence of genotoxic activity was observed in a series of S. typhimurium tester strains (TA Mix and TA 98)
in the absence and presence of metabolic activation. The test article is, therefore, classified as "Ames II negative".
Executive summary:

The Ames II assay is a high throughput version showing a high correlation with the traditional Salmonella assay. Concurrently with positive and negative (vehicle) controls, the test article was tested over a concentration range from 1 to 2500 μg/mL medium with and without microsomal rat liver enzymes (Aroclor 1254-induced). The bacterial tester strains S. typhimurium TA Mix (TA 7001, TA 7002, TA 7003, TA 7004, TA 7005 and TA 7006, sensitive to base-pair substitution) and TA 98 (susceptible to frameshift mutagens) are histidine-auxotrophic and were exposed with the test substance for 90 minutes. Using the liquid fluctuation technique revertant growth was quantified colorimetrically in 384-well plates after 48 hours at 37°C.

Solubility and Toxicity

CD 713 TD showed neither precipitation nor bacteriotoxicity up to the highest soluble concentration of 2500 μg/mL. The highest planned test concentration of 5000 μg/mL was not soluble in DMSO.

Mutagenicity

CD 713 TD did not increase consistently the number of positive wells in the different tester strains with and without S9 mix as compared to the vehicle control. The negative control showed a mean number of positive wells for S. typhimurium TA Mix (TA 7001- 7006) and TA 98 similar to those described in the literature (≤8/48 wells).

Based on the described results it is concluded, that CD 713 TD, when tested up to insoluble concentrations, caused neither base-pair substitutions nor frameshift mutations in bacteria. No evidence of genotoxic activity was observed in a series of S. typhimurium tester strains (TA Mix and TA 98) in the absence and presence of metabolic activation. The test article is, therefore, classified as "Ames II negative".