C.I. Pigment Violet 55

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:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

(1997)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

C.I. Pigment Violet 55

IUPAC Name:

C.I. Pigment Violet 55

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): C.I. Pigment Violet 55
- Substance type: Violet powder
- Physical state: solid

Method

Target gene:

- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

rat liver S9-mix induced by Aroclor 1254

Test concentrations with justification for top dose:

Main study: 1.7, 5.4, 17, 52, 164, 512, 1600 and 5000 µg/plate in the absence and presence of S9-mix

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The test substance was insoluble in distilled water at 50 mg/mL and was suspended in DMSO at 50 mg/mL. The test substance suspension of 50 mg/mL prepared with DMSO was considered to be stable from the fact that there was no change in color nor heat generation at room temperature within 2 hours after preparation. Therefore, DMSO was selected as a solvent.

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

2-nitrofluorene

sodium azide

methylmethanesulfonate

other: ICR-191,

Remarks:

without S9

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene in DMSO for all tester strains

Remarks:

with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Exposure duration: 48 hour

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in triplicate in each strain, except for the dose range finding test in which duplicate plates were tested for the substance and positive control groups. Two independent experiments were conducted.

NUMBER OF CELLS EVALUATED: 2.3x10E8 - 4.1x10E8 per plate

DETERMINATION OF CYTOTOXICITY
- Method: The reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies.

OTHER EXAMINATIONS:
- The presence of precipitation of the test compound on the plates was determined.

Evaluation criteria:

The test substance was judged positive when the number of revertant colonies increased to two times or more than that in the negative control in a concentration-dependent manner and also the reproducibility of the test results was obtained. In all other cases, it was judged negative.

Statistics:

Not performed.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Precipitation was observed at dose levels of 1250, 2500 and 5000 µg/plate

RANGE-FINDING/SCREENING STUDIES:
- No toxicity or mutagenicity was observed up to and including the top dose of 5000 µg/plate

COMPARISON WITH HISTORICAL CONTROL DATA:
- The negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- No toxicity or mutagenicity was observed up to and including the top dose of 5000 µg/plate

Any other information on results incl. tables

.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

All bacterial strains showed negative responses over the entire dose range, i.e. no significant dose-related increase in the number of revertants in two experiments. The negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

Based on the results of this study it is concluded that C. I. Pigment Violet 55 is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.

Executive summary:

C. I. Pigment Violet 55 was tested in the tester strains TA100 and WP₂uvrA at concentrations of 1.7, 5.4, 17, 52, 164, 512, 1600 and 5000 µg/plate in the absence and presence of S9-mix. Based on the results of the dose range finding test, the following dose range was selected for the mutation assay with the tester strains, TA1535, TA1537 and TA98 in the absence and presence of S9-mix: 17, 52, 164, 512 and 1600 μg/plate.

The results are shown in Table1 and Table2. The individual data are presented in APPENDIX3.

 

Precipitate

In the dose range finding test: Precipitation of C. I. Pigment Violet 55 on the plates was observed at the start and at the end of the incubation period at concentrations of 512 µg/plate and upwards. Except in tester strain TA100 in the presence of S9-mix, where the test substance only precipitated at dose levels of 1600 and 5000 µg/plate.

 

In the first mutation experiment: Precipitation of C. I. Pigment Violet 55 on the plates was observed at the start of the incubation period at concentrations of 512 µg/plate and upwards. At the end of the incubation period, precipitation of C. I. Pigment Violet 55 on the plates was observed at concentrations of 512 and 1600 µg/plate in the absence of S9-mix and at 1600 µg/plate in the presence of S9-mix.

 

Toxicity

To determine the toxicity of C. I. Pigment Violet 55, the reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies were examined. The definitions are stated in APPENDIX2.

 

No reduction of the bacterial background lawn and no biologically relevant decrease in the number of revertants were observed.

 

In tester strain TA100, a fluctuation in the number of revertant colonies below the laboratory historical control data range was observed at the dose level of 1600 µg/plate (absence of S9-mix, dose range finding). However, since no dose-relationship was observed, the reduction is not considered to be caused by toxicity of the test substance, rather it is more likely this reduction is caused by an incidental fluctuation in the number of revertant colonies.

 

Mutagenicity

No increase in the number of revertants was observed upon treatment with C. I. Pigment Violet 55 under all conditions tested.

 

To obtain more information about the possible mutagenicity of C. I. Pigment Violet 55, a second mutation experiment was performed in the absence of S9-mix and in the presence of 10% (v/v) S9-mix. Based on the results of the first mutation assay, C. I. Pigment Violet 55 was tested up to the dose level of 1568 µg/plate in strains TA1535, TA1537, TA98, TA100 and WP₂uvrA. The results are shown inTable3, the individual data are presented inAPPENDIX3.

 

Precipitate

Precipitation of C. I. Pigment Violet 55 on the plates was observed at the start and at the end of the incubation period at concentrations of 275 µg/plate and upwards.

 

Toxicity

No reduction of the bacterial background lawn and no biologically relevant decrease in the number of revertants were observed.

 

In strain TA100 and TA1537 (absence of S9-mix), fluctuations in the number of revertant colonies below the laboratory historical control data range were observed. However, since no dose-relationship was observed, the reductions are not considered to be caused by toxicity of the test substance.

 

Mutagenicity

In the second mutation assay, no increase in the number of revertants was observed upon treatment with C. I. Pigment Violet 55 under all conditions tested.