Magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The mutagenicity of magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2) was evaluated in a bacterial reverse mutation (Ames) assay, conducted according to OECD Test Guideline 471 and to GLP, using Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli strain WP2uvrA. The substance was tested by plate-incorporation up to the limit concentration of 5000 μg/plate, in the presence and absence of a rat liver-derived metabolic activation fraction (S9). There were no increases in revertant colony numbers over controls with any tested strains at any tested concentrations. Magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2)was therefore concluded to be non-mutagenic.

Two studies of the structurally-similar compound, fluorphlogopite, are also available.

The ability of fluorphlogopite to induce mutations at the HPRT locus of Chinese hamster V79 lung fibroblasts in culture was evaluated in a study conducted according to OECD Test Guideline 476 and to GLP. The substance was tested by up to a precipitating concentration of 500 μg/mL, in the presence and absence of a rat liver-derived metabolic activation fraction (S9) for 3 hours, and in the absence of S9 for 24 hours. There was no evidence of a mutagenic effect under the conditions of this assay. Fluorphlogopite was therefore concluded to be non-genotoxic.

The ability of fluorphlogopite to induce micronuclei in mammalian cells in culture was evaluated in Chinese hamster V79 lung fibroblasts, in a study conducted according to OECD Test Guideline 487 and to GLP. The substance was tested by up to a precipitating concentration of 15.8 μg/mL, in the presence and absence of a rat liver-derived metabolic activation fraction (S9) for 3 hours, and in the absence of S9 for 24 hours. There were no increases in micronucleus frequencies over controls under the conditions of this assay. Fluorphlogopite was therefore concluded to be non-genotoxic.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 August 1995 - 25 September 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1983.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1983.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

92/69/EEC, Method B.14

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Nonswellable mica MK (Micromica), supplied by Co-op Chemical Co., Ltd.
Lot No,. 637.

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not applicable

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- S9 obtained from the livers of male CD rats, 4 days after administration of a single intraperitoneal injection of Aroclor 1254.
- Supernatant from liver homogenate formed 1 mL out of total 12.1 mL S9 mix.
- 0.5 mL of S9 mix was added to the agar mix for the plate-incorporation assays.

Test concentrations with justification for top dose:

50, 158, 500, 1580, 5000 μg/plate.
Top dose is limit concentration for this assay.

Vehicle / solvent:

Plate incorporation test: Micromica was mixed with 0.15% aqueous agar.

Untreated negative controls:

yes

Remarks:

Dilution of bacterial culture plated on nutrient agar.

Negative solvent / vehicle controls:

yes

Remarks:

0.15% aqueous agar only (with and without S9 mix)

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

N-ethyl-N-nitro-N-nitrosoguanidine

benzo(a)pyrene

other: 2-aminoanthracene

Remarks:

9-aminoacridine, TA1537 without S9. 2-nitrofluorene, TA98, without S9. Sodium azide, TA100 and TA1535, without S9. ENNG, E. coli, without S9. B(a)p, TA98, TA100 and TA1537, with and without S9. 2-AA, TA1535 and E. coli, with and without S9.

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: all plates were prepared in triplicate.
- Number of independent experiments: two.

FOR GENE MUTATION:
- Expression time (cells in growth medium between treatment and selection): 2 days.
- Method used: agar plate-incorporation.

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method,: background growth inhibition

Evaluation criteria:

Not specified.

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

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:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Conclusions:

In a guideline bacterial reverse mutation test, magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2) gave no evidence of mutagenic activity in five strains of bacteria in the presence and absence of S9.

Executive summary:

The mutagenicity of magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2) was evaluated in a bacterial reverse mutation (Ames) assay, conducted according to OECD Test Guideline 471 and to GLP, using Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli strain WP2uvrA. The substance was tested by plate-incorporation up to the limit concentration of 5000 μg/plate, in the presence and absence of a rat liver-derived metabolic activation fraction (S9). There were no increases in revertant colony numbers over controls with any tested strains at any tested concentrations. Magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2) was therefore concluded to be non-mutagenic.

Reference 2

Endpoint:

in vitro cytogenicity / micronucleus study

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

14 January 2011 - 11 April 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline, GLP study conducted on read-across source substance.

Justification for type of information:

A full justification for the use of data on fluorphlogopite as read-across for this substance, magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), is attached to Section 13 of this dossier.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 487 (In vitro Mammalian Cell Micronucleus Test)

Version / remarks:

22 July 2010

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian cell micronucleus test

Specific details on test material used for the study:

Identification: Art. 278900 (Fluorphlogopite)
Batch number: K7211200M.
Particle Size: 10 - 40 µm
Expiry Date: 30 September 2015

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature, protected from direct sunlight.

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Details on mammalian cell type (if applicable):

CELLS USED
- Type and source of cells: V79 Chinese hamster lung fibroblasts. Original cultures obtained from Hoffmann-La Roche, Basel, Switzerland.

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- S9 obtained from the livers of male CD rats, after administration of a single intraperitoneal injection of Aroclor 1254.

Test concentrations with justification for top dose:

0.158, 0.5, 1.58, 5 and 15.8 µg/mL.

Test material suspensions interfered with scoring of the slides at high concentrations. The top dose, 15.8 µg/mL was selected as the maximum concentration.

Vehicle / solvent:

The test material was "absolutely insoluble" in any of the solvents tested. As a result, it was plated as a suspension in water.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

mitomycin C

other: Griseofulvin

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: Single
- Number of independent experiments: One

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable): 5 x 10^4 cells in 5 mL culture medium per slide.

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: 3 hours (with and without S9) and 24 hours (without S9 only)
- Harvest time after the end of treatment: Preparation of the cells was performed 24 hours after the start of treatment.

FOR CHROMOSOME ABERRATION AND MICRONUCLEUS:
- Methods of slide preparation: Cells were prepared using a hypotonic 2.25% sodium citrate solution and a fixative consisting of a mixture of 100 mL concentrated acetic acid + 300 mL ethanol + 5 mL 37.5% formaldehyde.
- Number of cells spread and analysed per concentration: 1000 cells/slide; 2 slides/concentration.
- Criteria for scoring micronucleated cells: Round particles with less than a third of the diameter of the main nucleus were scored as micronuclei where main and micronuclei were clearly separated from each other. Cells with fragmented nuclei were not counted.

Evaluation criteria:

The assay was considered valid if the mean MN frequencies in the solvent control fell within the normal range and at least one concentration of each of the positive control chemicals "relevantly increased" the incidence of MN as compared to the actual negative control (at least a 2-fold increase).

The test material was considered genotoxic if the assay was valid, a clear (at least 2-fold) increase in MN frequency occurs dose-dependently (over at least 2 concentrations) in two independent experimental series, and the maximum test material-induced MN frequency is above the highest historical control value.

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

In the presence and absence of S9, the MN frequencies for the fluorphlogopite-treated cells were not different from solvent controls.

Conclusions:

In a guideline test of micronucleus induction in mammalian cells (Chinese hamster V79 lung fibroblasts), fluorphlogopite, a substance closely structurally-related to magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), gave no evidence of genotoxicity, in the presence and absence of S9.

Executive summary:

The ability of fluorphlogopite, a substance closely structurally-related to magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), to induce micronuclei in mammalian cells in culture was evaluated in Chinese hamster V79 lung fibroblasts, in a study conducted according to OECD Test Guideline 487 and to GLP. The substance was tested by up to a precipitating concentration of 15.8 μg/mL, in the presence and absence of a rat liver-derived metabolic activation fraction (S9) for 3 hours, and in the absence of S9 for 24 hours. There were no increases in micronucleus frequencies over controls under the conditions of this assay. Fluorphlogopite, and consequently the target substance magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), are therefore concluded to be non-genotoxic.

Reference 3

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

07 February 2011 - 06 April 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline, GLP study conducted on read-across source substance.

Justification for type of information:

A full justification for the use of data on fluorphlogopite as read-across for this substance, magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), is attached to Section 13 of this dossier.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

21 July 1997

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian cell gene mutation test using the Hprt and xprt genes

Specific details on test material used for the study:

Identification: Art. 278900 (Fluorphlogopite)
Batch number: K7211200M.
Particle Size: 10 - 40 µm
Expiry Date: 30 September 2015

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature, protected from direct sunlight.

Target gene:

HPRT

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- S9 obtained from the livers of male Wistar rats, after administration of a single intraperitoneal injection of Aroclor 1254.

Test concentrations with justification for top dose:

15.8, 50, 158 and 500 µg/mL.

The highest concentration should precipitate in the culture medium, exhibit cytotoxicity or relevantly change the pH or osmolarity of the culture medium.

Vehicle / solvent:

The test material was "absolutely insoluble" in any of the solvents tested. As a result, it was tested as a suspension in water.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

other: N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG)

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: duplicate.
- Number of independent experiments: two.

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding: 1 x 10^6 per 150 mm-Petri dish
- Test substance added in medium.

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: 3 hours (with and without S9) and 24 hours (without S9 only)
- Harvest time after the end of treatment: Cultures maintained until day 5 (4 days after exposure to test material), when they are trypsinised, counted and subsequently cultured until day 8.

Evaluation criteria:

Test materials are assessed as positive (i.e. mutagenic) in this test system if a clear increase in the mutation frequency occurs at similar concentrations of the test material in the two independent experiments, a clear effect occurs in one experiment and a weak effect in the other, at identical concentrations, or weak effects occur dose-dependently over at least two test material concentrations, and reproducibly at identical concentrations in the two experiments.

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

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:

The test material, tested at the various concentrations up to the limits given by solubility, was not mutagenic in the V79 mammalian cell gene mutation test under conditions where the positive controls exerted potent mutagenic effects.

Conclusions:

In a guideline mammalian cell mutagenicity test in Chinese hamster V79 lung fibroblasts, fluorphlogopite, a substance closely structurally-related to magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), gave no evidence of genotoxicity, in the presence and absence of S9.

Executive summary:

The ability of fluorphlogopite, a substance closely structurally-related to magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), to induce mutations at the HPRT locus of Chinese hamster V79 lung fibroblasts in culture was evaluated in a study conducted according to OECD Test Guideline 476 and to GLP. The substance was tested by up to a precipitating concentration of 500 μg/mL, in the presence and absence of a rat liver-derived metabolic activation fraction (S9) for 3 hours, and in the absence of S9 for 24 hours. There was no evidence of a mutagenic effect under the conditions of this assay. Fluorphlogopite, and consequently the target substance magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2), was therefore concluded to be non-genotoxic.

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

In the Ames test, magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2) gave no evidence of mutagenic activity. The structurally-similar substance, fluorphlogopite, gave no evidence of mutagenicity in an Ames test, or in a mammalian cell mutation test, nor did it induce micronuclei in mammalian cells. Therefore, no classification is required.