Hydrogen bromide

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:

2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to OECD Guideline and GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Sodium bromide

EC Number:

231-599-9

EC Name:

Sodium bromide

Cas Number:

7647-15-6

IUPAC Name:

sodium bromide

Details on test material:

- Name of test material (as cited in study report): Natriumbromid
- Physical state: solid, white
- Analytical purity: 100.0%
- Lot/batch No.: A0294885
- Stability under test conditions: Guaranteed by the manufacturer till 21 Sep 2014
- Storage condition of test material: room temperature

Method

Target gene:

his, trp

Species / strain

Species / strain 1

Species / strain / cell type:

E. coli WP2 uvr A

Species / strain 2

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

Male Wistar rat liver S9, induced by phenobarbital (i.p.) and ß-naphthoflavone (p.o.)

Test concentrations with justification for top dose:

0, 33, 100, 333, 1000, 2500 and 5000 µg/plate

Vehicle / solvent:

water

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

sterility and vehicle controls

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: with S9: 2-aminoanthracene; without S9: N-methyl-N´-nitro-N-nitrosoguanidine, nitro-o-phenylendiamine, 9-aminoacridine, 4-nitroquinoline-N-oxide

Details on test system and experimental conditions:

Tester strains, doses, number of plates:

1st Experiment:
Strains: TA 1535, TA 100, TA 1537, TA 98
Doses: 0, 20, 100, 500, 2500 and 5000 ug/plate
Solvent: aqua dest.
Type of test, test conditions: standard plate test with and without S-9 mix
Number of plates: 3 test plates per dose or per control

2nd Experiment:
Strains: TA 1535, TA 100, TA 1537, TA 98
Doses: 0, 20, 100, 500, 2500 and 5000 ug/plate
Solvent: aqua dest.
Type of test, test conditions: preincubation test with and without S-9 mix
Number of plates: 3 test plates per dose or per control

Negative control:
Parallel with each experiment with and without S-9 mix, a negative control (solvent control, sterility control) is carried out for each tester strain in order to determine the spontaneous mutation rate.

Positive controls:
The following positive control substances are used to check the mutability of the bacteria and the activity of the S-9 mix:
with S-9 mix: 10 µg 2-aminoanthracene (2-AA) (dissolved in DMSO) for the strains TA 100, TA 98, TA 1537 and TA 1535;
without S-9 mix: 5 µg N-methyl-N'-nitro-N-nitrosoguanidine ( MNNG) (dissolved in DMSO) for the strains TA 100 and TA 1535; 10 µg 4-nitro-o-phenylendiamine (NPD) (dissolved in DMSO) for the strain TA 98; 100 µg 9-aminoacridine chloride monohydrate (AAC) (dissolved in DMSO) for the strain TA 1537.

Standard plate test:
Test tubes containing 2 mL portions of soft agar which consists of 100 mL agar (0.6% agar + 0.6% NaCl) and 10 mL amino acid solution (minimal amino acid solution for the determination of mutants: 0.5 mM histidine + 0.5 mM biotin) are kept in a water bath at 45°C, and the remaining components are added in the following order:
0.1 ml test solution or solvent
0.1 ml bacterial suspension
0.5 ml S-9 mix (in tests with metabolic activation) or 0.5 ml phosphate buffer (in tests without metabolic activation )
After mixing, the samples are poured onto Vogel-Bonner agar plates (minimal glucose agar plates) within approx. 30 seconds.

Preincubation test:
0.1 mL test solution or solvent, 0.1 mL bacterial suspension and 0.5 mL S-9 mix are incubated at 37°C for the duration of 20 minutes. Subsequently, 2 mL of soft agar is added and, after mixing, the samples are poured onto the Vogel-Bonner agar plates within approx. 30 seconds.
Composition of the minimal glucose agar: 980 mL aqua dest., 20 mL Vogel-Bonner E Medium, 15 g Difco bacto agar, 20 g D-glucose, monohydrate.
After incubation at 37°C for 48 hours in the dark, the bacterial colonies (his+ revertants) are counted.

S-9 mix:
The S-9 mix is prepared freshly prior to each experiment. For this purpose, a sufficient amount of S-9 fraction is thawed at room temperature and 1 volume of S-9 fraction is mixed with 9 volumes of S-9 supplement (cofactors).

Evaluation criteria:

Mutagenicity
Individual plate counts, the mean number of revertant colonies per plate and the standard deviations were given for all dose groups as well as for the positive and negative (vehicle) controls in all experiments. In general, six doses of the test substance are tested with a maximum of 5 mg/plate, and triplicate plating is used for all test groups at least in the 1st Experiment. Dose selection and evaluation as well as the number of plates used in repeat studies or further experiments are based on the findings of the 1st Experiment.

Toxicity
Toxicity detected by a decrease in the number of revertants; a clearing or diminution of the background lawn (= reduced his- or trp- background growth); a reduction in the titer is recorded for all test groups both with and without S9 mix in all experiments and indicated in
the tables.

Results and discussion

Test results

Test results 1

Species / strain:

E. coli WP2 uvr A

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

Test results 2

Species / strain:

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

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

Remarks on result:

other: strain/cell type:

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Under the experimental conditions chosen here, it is concluded that Natriumbromid is not a mutagenic test substance in the bacterial reverse mutation test in the absence and the presence of metabolic activation.