Potassium niobate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In vitro genetic toxicity studies using potassium niobate were not available, therefore data from two similar substances (Nb and K compounds) were used.

In a mammalian cell HPRT gene mutation assay, according to OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test), V79 cells cultured in vitro were exposed to niobium pentachloride (decomposed) (99.9 %) at concentrations of 0.025, 0.05, 0.10, 0.25, 0.50, 0.75, 1.0, 1.5 and 2.0 mM in the presence and absence of mammalian metabolic activation. There was no evidence of induced mutant colonies over background. The positive controls did induce the appropriate response. (Wallner, 2015)

The test compound NbCl5 was also considered to be negative in the Bacillus subtilis Rec Assay. (Kada, 1980)

In a reverse gene mutation assay in bacteria conducted similar to OECD test guideline 471, strains TA1535, TA1537, TA1538, TA98 and TA100 of Salmonella typhimurium were exposed to Potassium chloride at concentrations of 0, 1.86, 2.92, 5.84, 11.7 and 23.4 mg/plate in the presence and absence of mammalian metabolic activation. There was no evidence of induced mutant colonies over background in all tester strains. Therefore, Potassium chloride is considered to be non-mutagenic in this Salmonella typhimurium reverse gene mutation assay. (Seeberg et al. 1988)

In a reverse gene mutation assay in bacteria conducted similar to OECD test guideline 471, strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium were exposed to Potassium chloride at concentrations of 10, 33, 100, 333, 1000, 3333 and 10000 µg/plate in the presence and absence of mammalian metabolic activation. The positive controls induced the appropriate responses in the corresponding strains. There was no evidence of induced mutant colonies over background in all tester strains. Therefore, Potassium chloride is considered to be non-mutagenic in this Salmonella typhimurium reverse gene mutation assay.(Mortelmans, 1986)

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: guideline study from supporting substance (structural analogue)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

see box "Principles of method if other than guideline"

Principles of method if other than guideline:

Study conducted similar to OECD 471. However, only four Salmonella typhimurium strains were used.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

- Name of the test material (as cited in study report): Potassium chloride
- CAS number: 7447-40-7
- Purity: 99.99
- Source: Aldrich

Target gene:

Histidine locus

Species / strain / cell type:

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

Details on mammalian cell type (if applicable):

CELLS USED
- Source of cells: Cells were obtained from Dr. Bruce Ames, University of California, Berkeley, USA.

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced rat and hamster metabolic activation systems

Test concentrations with justification for top dose:

Test concentrations: 10, 33, 100, 333, 1000, 3333, 10000 µg/L

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: H2O

Untreated negative controls:

yes

Remarks:

Potassium chloride

Negative solvent / vehicle controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

TA1537, without S9

Untreated negative controls:

yes

Remarks:

Potassium chloride

Negative solvent / vehicle controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

all four strains, with S9

Untreated negative controls:

yes

Remarks:

Potassium chloride

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

TA1535 and TA100, without S9

Untreated negative controls:

yes

Remarks:

Potassium chloride

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylenediamine

Remarks:

TA98, without S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

EXPERIMENTAL PERFORMANCE
All chemicals were assayed for mutagenicity in the preincubation assay [Haworth et al., 1983]. To each of 13 x 100-mm test tubes maintained at 37 °C were added in the following order: 0.5 mL of S-9 mix or 0.1 M PO4 buffer (pH 7.4), 0.05 mL of the overnight culture, and 0.05 mL of solvent or chemical dilution. The mixture was mixed and allowed to incubate without shaking at 37 °C for 20 min, at which time 2.5 mL (EGG) or 2.0 mL (CWR, SFU) of molten (45 °C) top agar supplemented with 0.5 mM L-histidine and 0.5 mM D-biotin were added. The contents of the tubes were mixed and poured onto 25 mL of minimal glucose bottom agar [Vogel and Bonner, 1956] in 15 x 100-mm plastic petri dishes and Fisher Scientific plates. When the top agar had solidified, the
plates were inverted and incubated at 37 °C for 48 hr.

DURATION
- Preincubation period (Experiment II): 20 min at 37 °C
- Exposure duration: 48 h in the dark at 37 °C

NUMBER OF REPLICATIONS: 3 plates/strain/dose level per experiment. All experiments were repeated.

DETERMINATION OF CYTOTOXICITY
Cytotoxicity can be detected by appearance of his negative pinpoint colonies, reduced numbers of revertant colonies per plate, or thinning or absence of the bacterial lawn.

Evaluation criteria:

The criteria used for data evaluation were the same as those described previously [Haworth et al., 1983] and are summarized as follows: 1) mutagenic response: a dose-related, reproducible increase in the number of revertants over background, even if the increase was less than twofold; 2) nonmutagenic response: when no increase in the number of revertants was elicited by the chemical; 3) questionable response: when there was an absence of a clear-cut dose-related increase in revertants; when the dose-related increases in the number of revertants were not reproducible; or when the response was of insufficient magnitude to support a determination of mutagenicity. The initial determination of mutagenic, nonmutagenic, or equivocal was made by the testing laboratory; the final determination was made by the project officer (E.Z.). The chemicals were decoded by the chemical repository (Radian Corporation) only after the mutagenicity or nonmutagenicity of the chemicals had been determined.

Key result

Species / strain:

other: TA1535, TA1537, TA100 and TA98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

For detailed results please refer to table 1 in box "Any other information on results incl. tables"

Remarks on result:

other: non-mutagenic

Table 1: Test results (Lab: CWR, Solvent: H2O)

	TA100						TA1535						TA1537						TA98
Dose	Without hamster		With 10% hamster S9		With 10% rat S9		Without hamster		With 10% hamster S9		With 10% rat S9		Without hamster		With 10% hamster S9		With 10% rat S9		Without hamster		With 10% hamster S9		With 10% rat S9
µg/plate	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM
0	160	3.5	164	12.1	121	7.2	18	1.2	17	3.0	20	1.5	9	0.9	12	2.7	13	1.0	19	4.6	26	2.7	19	3.0
100	164	9.6	201	9.3	128	4.4	19	2.1	20	2.3	24	3.2	8	1.5	12	3.8	18	2.7	17	0.9	34	1.2	17	1.8
333	147	6.1	199	14.1	134	7.0	19	0.6	17	2.0	21	0.3	11	2.3	15	2.3	16	2.9	17	3.2	18	0.7	15	1.9
1000	166	2.2	199	11.4	115	4.0	15	1.5	22	1.3	15	2.9	11	1.2	12	1.5	14	1.3	15	3.2	18	2.2	20	1.2
3333	159	0.7	183	13.9	119	8.7	17	3.0	18	1.3	18	2.3	10	1.8	12	2.4	15	2.4	18	1.5	24	1.3	17	2.1
10000	t		181	20.9	103	1.8	14	2.1	20	4.5	18	2.0	t		11	1.5	15	1.3	14	3.0	19	0.3	18	2.8
POS	1707	21.1	2583	115.7	2143	52.4	1224	75.1	298	12.2	260	9.5	888	239.7	184	42.5	500	11.3	259	10.0	1322	66.6	1321	38.8

Table 2: Test results (Lab: EGG, Solvent: H2O)

	TA100						TA1535						TA1537						TA98
Dose	Without hamster		With 10% hamster S9		With 10% rat S9		Without hamster		With 10% hamster S9		With 10% rat S9		Without hamster		With 10% hamster S9		With 10% rat S9		Without hamster		With 10% hamster S9		With 10% rat S9
µg/plate	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM	MEAN	SEM
0	180	7.3	145	7.2	162	8.4	41	10.1	9	1.2	7	1.5	10	3.1	12	2.2	9	1.2	18	0.6	28	3.7	35	2.9
100	187	6.7	145	8.1	146	11.1	37	1.5	14	2.7	12	2.0	4	1.9	11	2.2	8	0.3	21	3.2	31	0.6	34	5.5
333	187	0.9	158	4.5	152	8.7	38	4.4	9	0.9	10	3.0	5	1.7	10	3.2	14	2.7	21	1.3	31	1.5	33	6.1
1000	187	11.5	160	3.2	180	2.8	36	2.3	12	0.9	12	1.2	6	0.3	10	3.3	11	0.6	23	2.3	34	4.0	36	0.9
3333	164	6.1	167	6.1	159	4.2	33	7.0	12	0.9	9	1.5	6	1.3	10	0.7	8	1.2	21	1.9	36	2.0	31	1.2
10000	180	11.3	141	5.8	164	2.3	29	5.2	9	2.6	9	2.9	9	1.3	9	0.9	9	1.5	14	1.2	38	3.3	33	4.1
POS	1166	14.8	1306	89.2	1821	113.5	965	44.4	131	7.9	101	3.9	334	191.8	142	4.3	125	5.5	1350	76.5	793	112.7	935	34.2

Conclusions:

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item can be considered as non-mutagenic.

Executive summary:

In a reverse gene mutation assay in bacteria conducted similar to OECD test guideline 471, strains TA98, TA100, TA1535 and TA1537 of Salmonella typhimurium were exposed to Potassium chloride in water at concentrations of 10, 33, 100, 333, 1000, 3333 and 10000 µg/plate in the presence and absence of mammalian metabolic activation. The positive controls induced the appropriate responses in the corresponding strains. There was no evidence of induced mutant colonies over background in all tester strains. Therefore, Potassium chloride is considered to be non-mutagenic in this Salmonella typhimurium reverse gene mutation assay.

Reference 2

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Principles of method if other than guideline:

Study conducted simliar to OECD 471.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

TEST MATERIAL
- Name: Potassium Chloride
- CAS number: 7447-40-7
- Batch: 29594
- Purity: 99.5%
- Source: B.D.H. Italia, Milano

Species / strain / cell type:

other: TA 1535, TA 1537, TA 1538, TA 98, TA 100

Details on mammalian cell type (if applicable):

CELLS USED
- Source of cells: Cells were obtained from Dr. Bruce Ames, University of California, Berkeley, USA

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

Test concentrations: 0, 1.86, 2.92, 5.84, 11.7 and 23.4 mg/plate

Vehicle / solvent:

Test solutions were prepared dissolving the test material directly in tissue culture media.

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

EXPERIMENTAL PERFORAMNCE
Cultures were grown overnight in a shaking water-bath in nutrient broth no. 2 from frozen stocks, and were used freshly. All incubations were at 37°C . Ames pour-plate assays were performed according to the methods described by Ames et al (1975). three plates were prepared at each test point, and all the results presented are the mean of the least two experiments performed.

NUMBER OF REPLICATIONS: 3 plates/strain/dose level per experiment. All experiments were repeated.

Key result

Species / strain:

other: TA 353, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not applicable

Untreated negative controls validity:

not examined

Positive controls validity:

not examined

Additional information on results:

For detailed results please refer to table 1 in box "Any other information on results incl. tables"

Table 1: Reversion of Salmonella tester strains by KCl

	mg/plate	1535	1537	1538	98	100
Absence of S9	0	21	17	22	38	127
	1.86	27	19	25	32	140
	3.73	25	17	25	25	132
	7.45	26	16	29	33	144
	14.9	29	18	25	30	134
	29.8	28	17	28	29	145
Presence of S9	0	17	22	35	51	137
	1.86	18	20	39	42	150
	3.73	15	19	38	42	140
	7.45	19	22	37	53	158
	14.9	19	20	38	44	154
	29.8	17	22	45	49	141

Conclusions:

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item can be considered as non-mutagenic.

Executive summary:

In a reverse gene mutation assay in bacteria conducted similar to OECD test guideline 471, strains TA1535, TA1537, TA1538, TA98 and TA100

of Salmonella typhimurium were exposed to Potassium chloride in nutrient broth no. 2 at concentrations of 0, 1.86, 2.92, 5.84, 11.7 and 23.4 mg/plate in the presence and absence of mammalian metabolic activation.

There was no evidence of induced mutant colonies over background in all tester strains. Therefore, Potassium chloride is considered to be non-mutagenic in this Salmonella typhimurium reverse gene mutation assay.

Reference 3

Endpoint:

in vitro DNA damage and/or repair study

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientific publication, which meets national/scientific standards.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Different types of DNA damage are subjected to cellular recombination repair, thus recombinationless bacteria are usually more sensitive than the wild type bacteria. After incubation with the test compound the length of the inhibition zones are measured and compared between the wild type and mutant strain for assessing the mutagenic potential of the test compound NbCl5.

GLP compliance:

not specified

Type of assay:

Bacillus subtilis recombination assay

Target gene:

Rec system (rec45 arg try)

Species / strain / cell type:

bacteria, other: Bacillus subtilis

Details on mammalian cell type (if applicable):

- Type and identity of media:
B-2 broth: (meat wet extract, 10 g; polypeptone dry powder, 10 g; NaCl, 5 g; water, 1000 ml; pH adjusted to 7.0.
Broth agar: 15g/L of agar added to the B-2 broth growing medium

Test concentrations with justification for top dose:

A test concentration is not mentioned, but it is mentioned for assaying samples of unknown potency:
For assaying samples of unknown potency, it is recommended that the assay be initiated with doses as high as possible using saturated solutions of each drug in a solvent. A negative result can be concluded under these conditions. By repeating the assays using solutions of lower drug concentrations, the clearest positiveness can be detected at a drug concentration where the inhibition zone for Rec+ bacteria is very close to zero.

Vehicle / solvent:

Besides water, available solvents are dimethylsulfoxide (DMSO), acetone, and ethyl acetate, which scarcely inhibit either Rec+ or Rec- bacteria, though no-drug "control" experiments must be carried out.

Untreated negative controls:

no

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

not specified

Details on test system and experimental conditions:

Strains H17 Rec+ and M45 Rec- are grown overnight in B-2 broth. One milliliter 50% glycerol (wt./vol.) is added to 3 ml fully grown bacterial broth culture, and the mixture is stored at -80°C. On the day of the experiments, each culture is thawed and streaked on the "dry" surface of broth agar, and the paper disk containing the test drug is positioned. The plates are kept at 4-5°C for 24 hr, then incubated at 37°C for about 20 hr. The length of the inhibition zone is then measured.

Species / strain:

bacteria, other: Bacillus subtilis

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Under the described test conditions, the test compound NbCl5 is considered to be negative in the Bacillus subtilis Rec Assay.

Executive summary:

In a Bacillus subtilis Rec Assay, the strain H17 Rec+ (rec+ arg try) and M45Rec- (rec45 arg try) were exposed to NbCl5. Only minor information were presented about the test compound concentration, the solubility and the used solvent/vehicle. Moreover, it is not clear, if positive controls were used during the test. Due to the simplicity of the assay and the well described protocol of Rec Assay

it can nevertheless be stated, that under the described test conditions, the test compound NbCl5 is considered to be negative in the Bacillus subtilis Rec Assay.

Reference 4

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-01-07 to 2015-04-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Rationale for reliability: guideline study from supporting substance (structural analogue)

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian cell gene mutation assay

Target gene:

HPRT

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Details on mammalian cell type (if applicable):

Type and identity of media:
Short-term exposure: MEM medium, 100 U/100 µg/ml penicillin/streptomycin, 2 mM L-glutamine, 25 mM HEPES, 2.5 µg/ml amphotericin B
Long-term exposure: MEM Medium with 10 % fetal bovine serum (FBS), 100 U/100 µg/ml penicillin/streptomycin, 2 mM L-glutamine, 25 mM HEPES, 2.5 µg/ml amphotericin B

Metabolic activation:

with and without

Metabolic activation system:

microsomal liver enzymes (S9)

Test concentrations with justification for top dose:

Pre-test for toxicity: 0, 0.0025, 0.005, 0.01, 0.05, 0.10, 0.25, 0.50, 1.0 mM without/with S9 mix
Main test:
Experiment I: 0, 0.025, 0.05, 0.10, 0.25, 0.50, 0.75, 1.0, 1.5 and 2.0 mM without/with S9 mix
Experiment II: 0, 0.005, 0.010, 0.025, 0.050, 0.10, 0.25, 0.50, 0.75, 1.0 mM without S9 mix
Experiment II: 0, 0.004, 0.007, 0.02, 0.04, 0.07, 0.2, 0.4, 0.7, 1.0 mM with S9 mix

Vehicle / solvent:

- vehicle/solvent used: 1% Ethanol/9% Aqua ad injectabilia
- justification for choice of solvent: Solubility test and pre-test for toxicity

Untreated negative controls:

yes

Remarks:

Treatment medium (MEM Medium)

Negative solvent / vehicle controls:

yes

Remarks:

1% ethanol/9% Aqua ad injectabilia

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Remarks:

without metabolic activation, final concentration 300 µg/ml

Untreated negative controls:

yes

Remarks:

Treatment medium (MEM Medium) plus S9 mix

Negative solvent / vehicle controls:

yes

Remarks:

1 % ethanol/9% Aqua ad injectabilia plus S9 mix

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

Remarks:

with metabolic activation, final concentration 0.8 and 1.0 µg/ml

Details on test system and experimental conditions:

Method of application: in medium
DURATION
- Preincubation period: 24 hours
- Exposure duration: 4 hours (short time exposure, Experiment I with and without metabolic activation)
20 hours (long time exposure, Experiment II with and without metabolic activation)
- Expression time (cells in growth medium): 6 days (subcultered after 3 days)
- Selection time (if incubation with a selection agent): 7-11 days
- Fixation time (start of exposure up to fixation or harvest of cells): 13-17 days

SELECTION AGENT (mutation assays): 6-Thioguanine

NUMBER OF REPLICATIONS: one culture per test group (expression period), 5 dishes per culture per test group (selection period)

DETERMINATION OF CYTOTOXICITY
- Methods: Relative Growth, Cloning efficiency

Evaluation criteria:

- Negative and/or solvent controls fall within the performing laboratories historical control data range: 2-44 mutants/10^6 cells
-The absolute cloning efficiency: ([number of positive cultures x 100] I total number of seeded cultures) of the negative and /or
solvent controls is > 50%
-The positive controls (EMS and DMBA) induce significant increases (at least 3-fold increase of mutant frequencies related to the comparable negative control values and higher than the historical range of negative controls) in the mutant frequencies.
- A test is considered to be negative if there is no biological relevant increase in the number of mutants.
- There are several criteria for determining a positive result: a reproducible three times higher mutation frequency than the solvent control for at least one of the concentrations
- a concentration related increase of the mutation frequency; such an evaluation may be considered also in the case that a three-fold increase of the mutant frequency is not observed
- if there is by chance a low spontaneous mutation rate in the corresponding negative and solvent controls a concentration related increase of the mutations within their range has to be discussed.
- According to the OECD guidelines, the biological relevance of the results is the criterion for the interpretation of results, a statistical evaluation of the results is not regarded as necessary.

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

A biologically relevant growth inhibition (reduction of relative growth below 70%) was observed after the treatment with the test item in experiment I and II without metabolic activation

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: The pH-value detected with the test item was within the physiological range (pH 7.0 ± 0.4).
- Effects of osmolality: not examined
- Precipitation: Precipitation of the test item was noted in experiment I without metabolic activation at concentrations of 0.5 mM and higher and with metabolic activation at concentrations of 0.25 mM and higher. In experiment II precipitation was detected at concentrations of 0.2 mM and higher with metabolic activation.

RANGE-FINDING/SCREENING STUDIES:
A solubility test was performed with different solvents and vehicles. Based on the results of the solubility test EtOH was used as solvent. After pre-dissolving the test item in EtOH (100 mM) a dilution series was prepared in EtOH. First a 9fold volume of phosphate buffer was used adding it to each concentration. After noticing that in the pre-experiment without metabolic activation the buffer reacts with the cells the phosphate buffer was replaced for the main experiments by Aqua ad injectabilia. So the 9fold volume of Aqua ad injectabilia was added to each concentration. After an initial reaction of approx. 10 minutes, this test item solution was added to cell culture medium (MEM without serum) at a ratio of 1 :10, resulting in 1% EtOH and 9% Aqua ad injectabilia in the final treatment medium. The pH-value detected with the test item was within the physiological range (pH 7.0 ± 0.4). The solvent used is a composition of well-established solvents and is compatible with the survival of the cells and the activity of the S9 mix The toxicity of the test item was determined in pre-experiments. Eight concentrations [0.0025, 0.005, 0.01, 0.050, 0.10, 0.25, 0.50, 1.0 mM] were tested without and with metabolic activation. In the pre-experiment the test item concentrations were dissolved in 1% ethanol and 9% phosphate buffer. The experimental performance for the pre-experiment was the same as described below for the main experiments (excepting the solvent composition)

COMPARISON WITH HISTORICAL CONTROL DATA:
In all experiments the mutant values of the negative controls, the solvent controls and all mutant values of the test item concentrations found were within the historical control data of the test facility (without metabolic activation: 2-43 mutants per 10^6 cells, with metabolic activation: 5-44 mutants per 10^6 cells

Remarks on result:

other: strain/cell type:

Remarks:

Migrated from field 'Test system'.

Table 4
Experiment I - Mutagenicity, without metabolic activation
Dose Group	Concentration [mM]	Number of mutant colonies per flask^a					Mean	SD	Mutant SD colonies per 10^6 cells^b	Mutation factor
		I	II	III	IV	V
NC1	0	6	6	9	10	6	7.4	1.74	20.11
NC2		4	6	6	*	8	6	1.41	18.29
S1	0	9	10	13	16	10	11	2.58	33.72
S2		7	6	9	8	10	11.6	1.41	23.46
2	0.025	6	6	5	14	9	8	3.29	20.05	0.69
3	0.05	5	3	6	2	8	4.8	2.14	14.08	0.48
4	0.1	4	4	6	5	12	6.2	2.99	18.34	0.63
5	0.25	9	10	10	7	5	8.2	1.94	25.39	0.87
6	0.5	6	11	5	5	7	6.8	2.23	18.28	0.63
7	0.75	15	14	11	15	18	14.6	2.24	40.67	1.4
8	1.0	9	6	6	12	12	9	2.68	25.86	0.89
9	1.5	3	5	5	4	7	4.8	1.33	14.72	0.51
10	2.0	9	13	6	9	6	8.6	2.58	25.83	0.89
EMS	300 µg/mL	84	72	80	89	90	83	6.57	233.15	8.01
NC:	negative control/ medium control
S:	solvent control
a:	number of mutant colonies in flask I to V
b:	mean mutant colonies x 10^6/ (400000 x Cloning Efficiency/100)
EMS:	Ethylmethanesulfonate [300 µg/mL]
*:	Contamination of cell culture in flask

Table 6
Experiment I - Mutagenicity, with metabolic activation
Dose Group	Concentration [mM]	Number of mutant colonies per flask^a					Mean	SD	Mutant SD colonies per 10^6 cells^b	Mutation factor
		I	II	III	IV	V
NC1	0	5	5	6	6	11	6.6	2.24	20.06
NC2		2	5	7	11	11	7.2	3.49	20.11
S1	0	3	5	6	7	10	6.2	2.32	18.62
S2		3	4	9	9	10	7.0	2.90	19.83
2	0.025	4	4	5	6	10	5.8	2.23	14.61	0.76
3	0.05	5	12	8	3	8	7.2	3.06	18.56	0.97
4	0.10	11	10	11	10	11	10.6	0.49	30.64	1.59
5	0.25	5	6	7	10	14	8.4	3.26	20.64	1.07
6	0.50	2	2	4	5	5	3.6	1.36	9.65	0.50
7	0.75	3	7	8	9	9	7.2	2.23	19.15	1.00
8	1.0	4	8	11	12	12	9.4	3.07	25.61	1.33
9	1.5	7	7	8	8	9	7.8	0.75	18.22	0.95
10	2.0	7	7	9	9	11	8.6	1.50	22.34	1.16
DMBA	0.8µg/mL	105	107	133	96	97	107.6	13.41	303.95	15.81
DMBA	1.0µg/mL	111	149	118	122	109	121.8	14.39	369.09	19.20
NC:	negative control/ medium control
S:	solvent control
a:	number of mutant colonies in flask I to V
b:	mean mutant colonies x 10^6/ (400000 x Cloning Efficiency/100)
DMBA:	7, 12-Dimethylbenz(a)anthracene [0.8 and 1.0 µg/mL]

Table 8
Experiment II - Mutagenicity, without metabolic activation
Dose Group	Concentration [mM]	Number of mutant colonies per flask^a					Mean	SD	Mutant SD colonies per 10^6 cells^b	Mutation factor
		I	II	III	IV	V
NC1	0	8	9	10	6	5	7.6	1.85	21.05
NC2		14	8	5	9	12	9.6	3.14	26.89
S1	0	15	7	8	9	12	10.2	2.93	29.74
S2		9	12	9	8	5	8.6	2.24	24.02
2	0.025	16	4	8	5	6	7.8	4.31	25.91	0.96
3	0.010	10	12	12	11	7	10.4	1.85	33.02	1.23
4	0.025	12	5	10	10	5	8.4	2.87	25.23	0.94
5	0.050	15	15	8	13	13	12.8	2.56	36.57	1.36
6	0.10	8	18	12	18	14	14.0	3.79	39.11	1.45
7	0.25	10	10	7	10	10	9.4	1.2	26.26	0.98
8	0.50	16	10	13	8	20	13.4	4.27	37.22	1.38
9	0.75	14	7	18	16	15	14.0	3.74	35.90	1.34
10	1.0	9	12	8	11	8	9.6	1.62	27.12	1.01
EMS	300µg/mL	160	175	179	169	177	172.0	6.87	607.77	22.61
NC:	negative control/ medium control
S:	solvent control
a:	number of mutant colonies in flask I to V
b:	mean mutant colonies x 10^6/ (400000 x Cloning Efficiency/100)
EMS:	Ethylmethanesulfonate [300 µg/mL]

Table 10
Experiment II - Mutagenicity, with metabolic activation
Dose Group	Concentration [mM]	Number of mutant colonies per flask^a					Mean	SD	Mutant SD colonies per 10^6 cells^b	Mutation factor
		I	II	III	IV	V
NC1	0	13	10	8	11	3	9.0	3.41	24.93
NC2		19	12	18	12	16	15.4	2.94	43.38
S1	0	3	8	6	5	3	5.0	1.90	13.7
S2		9	7	12	13	5	9.2	2.99	25.41
2	0.004	13	13	8	13	6	10.6	3.01	26.84	1.37
3	0.01	4	10	8	7	8	7.4	1.96	20.11	1.03
4	0.02	5	12	7	11	7	8.4	2.65	22.22	1.14
5	0.04	9	8	11	12	6	9.2	2.14	23.41	1.20
6	0.07	15	6	10	12	7	10.0	3.29	25.71	1.31
7	0.2	7	8	4	11	14	8.8	3.43	26.19	1.34
8	0.4	9	13	14	17	13	13.2	2.56	35.97	1.84
9	0.7	9	13	12	9	6	9.8	2.48	29.17	1.49
10	1.0	13	10	14	12	13	12.4	1.36	35.63	1.82
DMBA	0.8µg/mL	77	89	71	88	90	83.0	7.62	244.12	12.48
DMBA	1.0µg/mL	109	120	126	106	114	115.0	7.27	357.14	18.26
NC:	negative control/ medium control
S:	solvent control
a:	number of mutant colonies in flask I to V
b:	mean mutant colonies x 10^6/ (400000 x Cloning Efficiency/100)
DMBA:	7, 12-Dimethylbenz(a)anthracene [0.8 and 1.0 µg/mL]

Conclusions:

Under the experimental conditions, the test item niobium pentachloride (decomposed) is considered to be non-mutagenic in the HPRT locus using V79 cells of the Chinese Hamster.

Executive summary:

In a mammalian cell HPRT gene mutation assay, V79 cells cultured in vitro were exposed to niobium pentachloride (decomposed) (99.9 %) in 1% ethanol and 9% Aqua ad injectibilia at concentrations of 0.025, 0.05, 0.10, 0.25, 0.50, 0.75, 1.0, 1.5 and 2.0 mM in the presence and absence of mammalian metabolic activation (experiment I) and for experiment II at concentrations of 0.005, 0.010, 0.025, 0.050, 0.10, 0.25, 0.50, 0.75 and 1.0 mM without metabolic activation and 0.004, 0.007, 0.02, 0.04, 0.07, 0.2, 0.4, 0.7 and 1.0 mM with metabolic activation.

In experiment I and II with and without metabolic activation mutant values of the negative controls, the solvent controls and all mutant values of the test item concentrations found were within the historical control data.

For all tested treatment groups no dose-response relationship could be observed. The positive controls did induce the appropriate response. There was no evidence of induced mutant colonies over background. 

This study is classified as acceptable. This study satisfies the requirement for Test Guideline OPPTS 870.5300, OECD 476 for in vitro mutagenicity (mammalian forward gene mutation) data.

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

Based on negative in vitro genetic toxicity data from two structurally similar substances, niobium pentachloride and potassium chloride, utilizing OECD 476 and OECD 471, respectively, can be concluded that potassium niobate would also be non-mutagenic.