Sodium bis[3-[[1-(3-chlorophenyl)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-4-yl]azo]-4-hydroxy-N-methylbenzene-1-sulphonamidato(2-)]chromate(1-)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test material did not induce mutations in a bacterial reverse mutation assay (Ames test).

Link to relevant study records

Reference

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:

2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Standard Study according to guideline and GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S-9 mix

Test concentrations with justification for top dose:

33; 1 00; 333; 1 000; 2500; and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO;
- Justification for choice of solvent/vehicle: Standard solvent used in this assay

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 4-nitro-o-phenylene-diamine (4-NOPD); 2-aminoanthracene (2-AA)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation;

DURATION
- Preincubation period: 60 minutes
- Exposure duration: 48 h

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: other:Toxicity of the test item results in a reduction in the number of spontaneous revertants or a clearing of the bacterial background lawn.

Evaluation criteria:

Acceptability of the Assay
The Salmonella typhimurium and Escherichia coli reverse mutation assay is considered acceptable if it meets the following criteria:
- regular background growth in the negative and solvent control
- the spontaneous reversion rates in the negative and solvent control are in the range of our historical data
- the positive control substances should produce a significant increase in mutant colony frequencies

Evaluation of Results
A test item is considered positive if either a dose related increase in the number of revertants or a biologically relevant increase for at least one test concentration is induced.
A test item producing neither a dose related increase in the number of revertants nor a biologically relevant response at any one of the test points is considered non-mutagenic in this system.
A biologically relevant response is described as follows:
A test item is considered as mutagenic if in strains TA 98, TA 100, and WP2 uvrA the number of reversions is at least twice as high and in strains TA 1535 and TA 1537 at least three times higher as compared to the spontaneous reversion rate.
Also, a dose-dependent increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test item regardless whether the highest dose will induce the above described enhancement factors or not.

Key result

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

without S9 Mix

Concentration	Revertants/plate
µg/plate	mean from three plates
	TA 1535		TA 1537		TA 98		TA 100		WP2 uvrA
Negative control	9	12	5	14	22	28	141	136	44	48
Solvent control	12	17	6	12	18	31	165	112	43	42
Positive control*	742	703	54	66	214	201	861	864	810	710
33	9	16	7	19	23	28	164	135	59	50
100	13	15	7	15	20	35	138	118	35	54
333	14	14	5	13	16	26	119	115	43	49
1000	12	12	5	11	13	23	142	91	46	44
2500	13	10	4	7	13	26	117	77	40	46
5000	6	8	5	3	12	9	132	53	39	45

 

with S9 Mix

Concentration	Revertants/plate
µg/plate	mean from three plates
	TA 1535		TA 1537		TA 98		TA 100		WP2 uvrA
Negative control	12	14	8	23	24	32	165	177	54	57
Solvent control	15	15	7	18	23	32	159	138	42	53
Positive control**	176	126	76	54	413	319	863	706	256	192
33	15	15	7	19	23	28	164	135	59	50
100	12	19	13	14	24	32	141	127	58	50
333	12	15	8	14	32	35	147	132	49	61
1000	17	16	13	11	25	27	147	121	44	48
2500	9	14	9	8	13	27	109	83	26	52
5000	10	8	1	8	11	25	121	90	24	43

* Sodium azide (10.0 µg/plate)strains TA 1535 and TA 100

4-nitro-o-phenylene-diamine strains TA 1537 (50 µg/plate) and TA 98 (10.0 µg/plate)

Methyl methane sulfonate (5 µL/plate) strain WP2 uvrA

** 2-aminoanthracene (2.5 µg/plate) strains TA 1535, TA 1537, TA 98, and TA 100

2-aminoanthracene (1 0.0 µg/plate) strain WP2 uvrA

Conclusions:

Interpretation of results (migrated information):
negative

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

Executive summary:

This study was performed to investigate the potential of the test item to induce gene mutations according to the plate incorporation test (experiment I) and the preincubation test (experiment II) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

The assay was performed in two independent experiments both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate.

The test item was tested at the following concentrations: 33; 1 00; 333; 1 000; 2500; and 5000 µg/plate

The plates incubated with the test item showed normal background growth up to 5000 µg/plate with and without metabolic activation in both independent experiments.

Toxic effects, evident as a reduction in the number of revertants, occurred in some of the strains at higher concentrations.

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with the test item at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance. Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.

Conclusion

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used. Therefore,the test item is considered to be non-mutagenic in this Salmonella typhimurium and Escherichia coli reverse mutation assay.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

No classification.

The test material did not induce mutations in a bacterial reverse mutation assay (Ames test).