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Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test substance, Direct Brown 103, was non mutagenic for all the Salmonella typhimurium as well as Escherichia coli strains with as well as without metabolic activation.

Link to relevant study records
Reference
Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
04.04.2017 – 19.05.2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
Council Regulation (EC) No.440/2008. Published in O.J. L 142, 2008
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
bacterial reverse mutation assay
Target gene:
gene for histidine or tryptophan synthesis
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
supernatant of rat liver and a mixture of cofactors
Test concentrations with justification for top dose:
50, 150, 500, 1500, 5000 μgSelection of doses/toxicity: Sponsor declared solubility 25 g per litre what is half solubility recommended in OECD TG 471. The test substance was then dissolved in dimethyl sulfoxide till the maximum recommended concentration 5000 μg per 0.1 mL. For toxicity experiment the highest concentration was diluted to the other 5 concentrations in 3 digit places interval. Although eventual particles could not be observed in higher concentrations due to dark colour of solutions, actually no particles were observed in top agar and Petri dishes.
Vehicle / solvent:
Dimethyl sulfoxide, Merck Lo.No. K47112152544, Lot. No. K48069852644- Justification for choice of solvent/vehicle: solubility of the substance
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
water
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
(AS)
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylenediamine
Remarks:
(NPD)
Positive controls:
yes
Positive control substance:
other: 2-aminofluorene
Remarks:
(2-AF)
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
(2-AA)
Positive controls:
yes
Positive control substance:
other: N-methyl-N´-nitro-N-nitrosoguanidine
Remarks:
(MNNG)
Positive controls:
yes
Positive control substance:
other: 9-aminoacridine hydrochloride monohydrate
Remarks:
(9-AAc)
Details on test system and experimental conditions:
The bacterial tester strains Salmonella typhimurium TA 1535 (CCM 3814, lot. No. 2101200916917), TA 98 (CCM 3811, lot No. 01022001220053), TA 100 (CCM 3812, lot No. 0102201220054) and TA 1537 (CCM 3815, lot No. 2101200916918) as well as Escherichia coli WP2 uvrA (CCM 4751, lot No. 2104200512732),were obtained from Czech Collection of Microorganisms (CCM) of Masaryk University, Brno.Strains TA 98 and TA 1537 detect frame shift mutations, strains TA 100 and TA 1535 serve to detection of base-pair substitution mutations, and strain E.coli WP2uvrA detects cross-linking mutagensMETHOD OF APPLICATION: in medium; in agar (plate incorporation)NUMBER OF REPLICATIONS: two seriesDETERMINATION OF CYTOTOXICITY- Method: relative total growth
Evaluation criteria:
The main criterion for evaluation of results was modified two-fold increase rule, which is compatible with the application of statistical methods (see below). After this rule the result is positive, if a reproducible doseresponse effect occurs and/or a doubling of the ratio Rt/Rc is reached.
Statistics:
For the evaluation of results, the modified two-fold increase rule was used, which is compatible with the application of statistical methods:Dunkel V. C.. Chu K.C. (1980): Evaluation of methods for analysis of microbial mutagenicity assays in The Predictive Value of Short-Term Screening Tests in Carcinogenicity Evaluation. Elsevier North-Holland Biomedical Press. 231 - 417Claxton L. D. et al. (1987): Guide for the Salmonella typhimurium/mammalian microsome tests for bacterial mutagenicity. Mutat. Res. 189. 83 - 91
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
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:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
HISTORICAL CONTROL DATA: Each experiment included corresponding positive (reference mutagens) and negative controls (untreated control, solvent control). Untreated controls contain no solvent and negative controls contain 0.1 mL of DMSO. All the control numbers were compared with historical ranges of mutant frequencies obtained in our laboratory. The actual numbers were in ranges of the historical numbers. ADDITIONAL INFORMATION ON CYTOTOXICITY:Sponsor declared solubility 25 g per litre what is half solubility recommended in OECD TG 471. The test substance was then dissolved in dimethyl sulfoxide till the maximum recommended concentration 5000 μg per 0.1 mL. For toxicity experiment the highest concentration was diluted to the other 5 concentrations in 3 digit places interval. Although eventual particles could not be observed in higher concentrations due to dark colour of solutions, actually no particles were observed in top agar and Petri dishes. The concentration row was tested for toxicity in strain TA 98 without metabolic activation. No toxicity or precipitation was observed in any dose. The concentration of 5000 µg. 0.1 mL-1 was then used as maximum in the first mutagenicity experiments. Further doses were diluted with factor approximately 2-√10.
Conclusions:
Under the above-described experimental design, the test substance, Direct Brown 103, was non mutagenic for all the Salmonella typhimurium as well as Escherichia coli strains with as well as without metabolic activation.
Executive summary:

The test substance Direct Brown 103 was assayed for the mutagenicity by the Bacterial Reverse Mutation Test. The performed test was based on EU method B.13/14 Mutagenicity – Reverse mutation test using bacteria, which is analogous to the OECD Test Guideline No. 471.

Four indicator Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and one indicator Escherichia coli WP2 uvrA strain were used. The test substance was diluted in DMSO and assayed in doses of 50 - 5000 μg per plate, which were applied to plates in volume of 0.1 mL.

The first mutagenicity experiments were performed without and with metabolic activation using a supernatant of rat liver (30 μL or 100 μL per plate) and a mixture of cofactors by the plate incorporation test with a dose range of 50 – 5000 μg per plate.

To modify experimental conditions and to increase the sensitivity of the assay, the second mutagenicity experiments with metabolic activation were performed with 50 μL of S9.

The concurrent positive controls verified the sensitivity of the assay and the metabolising activity of the liver preparations. Average revertant colony counts for the vehicle controls were within the current historical control range for the laboratory.

In the arrangement given above, the test substance, Direct Brown 103, was non-mutagenic for all the used tester strains without as well as with metabolic activation.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Justification for classification or non-classification