Cyclohexanone oxime

Genetic toxicity: in vitro

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

Study period:

1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Limited documentation and incomplete set of bacterial tester strains (sufficient to detect a positive response, would not be considered reliable in case of negative results)

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1996

Report date:

1996

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

incomplete set of tester strains

GLP compliance:

yes

Remarks:

In compliance with U.S. Food and Drug Administration Good Laboratory Practices regulations (21 CFR, Part 58)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Cyclohexanone oxime

EC Number:

202-874-0

EC Name:

Cyclohexanone oxime

Cas Number:

100-64-1

Molecular formula:

C6H11NO

IUPAC Name:

cyclohexanone oxime

Test material form:

solid: crystalline

Details on test material:

- Name of test material (as cited in study report): cyclohexanone oxime
- Substance type: white crystalline solid
- Analytical purity: > 99% for both lots used
- Impurities (identity and concentrations):
- Lot/batch No.: Lots 02616LT and 08812MX
- Stability under test conditions: no degradation of cyclohexanone oxime throughout the study
- Storage condition of test material: stable in aqueous solution at a concentration of 106 ppm for 4 weeks at 5 °C when stored in a sealed container, protected from light. Solutions exposed to light in drinking water bottles were stable for 5 days. Substance stored in a sealed container at 5 °C or less, protected from light.

Method

Target gene:

Histidine

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 97

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

not specified

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 1535

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

Liver S9 fraction from Aroclor 1254-induced a) male Sprague-Dawley rats and b) Syrian hamsters

Test concentrations with justification for top dose:

0, 10, 33, 100, 333, 1000, 3333, for TA 1535 with metabolic activation additionally 666, 1666 and 6666 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylenediamine

Remarks:

for TA98 withiut metabolic activation

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

for TA100 and TA1535 without metabolic activation

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

for TA97 without metabolic activation

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

for all tests with metabolic activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 min at 37 °C
- Exposure duration: 2 d at 37 °C

SELECTION AGENT (mutation assays): histidine

NUMBER OF REPLICATIONS: 3

Evaluation criteria:

Positive: reproducible, dose-related increase in revertant colonies (no minimum percentage defined)
Equivocal: not dose related, not reproducible, not of sufficient magnitude
Negative: no increase

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

A negative and an equivocal results were obtained in 2 independent trials

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with

Genotoxicity:

positive

Remarks:

Positive result with hamster S9 liver mix, with rat S9 liver mix negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 6666 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Results of tests with hamster S9 liver fraction in varying concentrations:
5%, 2 independent trials: negative/positive
10%: 3 independent trials: negative/positive/positive
30%: 3 independent trials: equivocal/equivocal/positive

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):
positive with metabolic activation

Under the conditions of this study the test item induced mutations in Salmonella TA1535 in the presence of metabolic activation

Executive summary:

Testing was performed in a Salmonelly typhimurium mutagenicity assay according to Zeiger et al. (1992). The test item was incubated with Salmonella typhimurium tester strains TA97, TA98, TA100 and TA1535 with or without metabolic activation in concentrations of 0, 10, 33, 100, 333, 1000, 3333 µg/plate (for TA 1535 with metabolic activation additionally 666, 1666 and 6666 µg/plate). The S9 liver fraction was derived from Aroclor 1254-induced male Sprague-Dawley rats or Syrian hamster liver. After 20 min preincubation of the test item with bacteria at 37°C the samples were plated in triplicates and incubated for 2 days at 37 °C. The results in the strains TA97, TA98 and TA100 were negative, as well as in TA1535 without metabolic activation (no cytotoxicity up to the highest concentrations tested). A positive response was obtained in TA1535 with metabolic activation by hamster S9 mix (not with rat S9 liver fraction) in 2 independent trials.

Appropriate positive controls showed a mutagenic response, thus confirming the validity of this study.

Under the conditions of this study the test substance was positive in TA1535 with metabolic activation.