Calcium magnesium strontium carbonate hydroxide phosphate (4.3-4.7 : 0.1-0.3: 0.2-0.5 : 0.3-0.5 : 0.2-0.6 : 3)

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: study well documented with acceptable restrictions

Justification for type of information:

Justification for Read Across is given in Section 13 of IUCLID

Data source

Reference

Reference Type:

publication

Title:

In vitro effect of fluor-hydroxyapatite, fluorapatite and hydroxyapatite on colony formation, DNA damage and mutagenicity

Author:

Jantová Sona, Theiszová M., Letašiová Silvia, Birošová L., Palou Tchingnabe Palou

Year:

2008

Bibliographic source:

Mutat Res. 2008 Apr 30;652(2):139-44

Materials and methods

Principles of method if other than guideline:

The bacterial mutagenicity test of the substance is evaluated by using Salmonella typhimurium TA100 according to Maron and Ames.
D.M. Maron, B.N. Ames. Revised methods for Salmonella mutagenicity test, Mutat. Res. 113 (3-4) (1983) 173-215

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Fluorohydroxyapatite

Molecular formula:

Ca10(PO4)6(OH)F

IUPAC Name:

Fluorohydroxyapatite

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 100

Metabolic activation:

without

Test concentrations with justification for top dose:

1-5-10-25-50-75-100 %

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-Methyl-N′-nitro-N-nitrosoguanidine (ΜΜΝG) - stock solution was 1 μg/ml

Details on test system and experimental conditions:

PREPARATION OF BIOMATERIAL ELUATES
The test material powders (porous size was less than 125 μm, shot 100 mg/ml) were used for preparation of 5-day´s concentrated eluates (non-diluted). Culture medium supplemented with penicillin and streptomycin was used. Biomaterial powders was sterilized for 30 min at 130 °C, then the cultivation medium was added and samples were shaken on reciprocal shaker for 5 days at 37 °C. After 5 day eluation the concentrated samples were centrifugated (10 min, 1100 g), the culture medium was aspirated by syringe and filtered (Ø 0.22 μm). This procedure led to preparation of 100 % (concentrated, non-diluted) of biomaterial eluates which pH was in the range 6.8 – 7.1. Eluates were stored at -20 °C. Before experiment these concentrated eluates were diluted by culture medium to concentrations tested (75, 50, 25, 10, 5 and 1 %).

TEST SYSTEM
TA100 was received from the Collection of Microorganisms, Masaryk University, Brno (Czech Republic). It was stored at -80 °C and regularly checked for their genetic markers.

PERFORMANCE OF THE TEST
Bacterial strain Salmonella typhimurium TA100 was cultivated on nutrient agar and 16 h before experiment overnight culture was prepared in nutrient broth. The strain was used for its sensitivity for a broad spectrum of chemical compounds. The plate- incorporation method was used. To 2 ml of melted top agar containing 50 μM of L-histidine-biotin, 0.1 ml of a cell suspension (overnight cultivation at 37 °C, approximate cell density 2-5 x 10^8 cells/ml) and 0.1 ml of a solution of the tested compound were added. The mixture was poured onto a minimal glucose agar plate and incubated for 48 h at 37 °C and then the number of histidine- independent revertants was counted. Data points represents at least three separate experiments, each run in triplicate.

Evaluation criteria:

A positive response was defined as a reproducible, two-fold increase of revertants with dose-response relationship.

Statistics:

Student´s t-test

Results and discussion

Test results

Species / strain:

S. typhimurium TA 100

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

Additional information on results:

- The highest tested concentration (100 %) of tge test material did not induce growth of revertants. No mutagenic activity was observed.
- Positive control MNNG induced mutagenic activity in Salmonella typhimurium TA100.

Applicant's summary and conclusion

Conclusions:

No mutagenic activity was observed

Executive summary:

Τhe bacterial mutagenic potential of the substance on Salmonella typhimurium TA100 was evaluated in the plate-incorporation method.

S. Typhimurium TA100 was exposed to 1-5-10-25-50-75-100 % of the test material, Positive control (MMNG) run in parallel. A positive response was defined as a reproducible, two-fold increase of revertants with dose-response relationship and statistical evaluation using Student´s t-test.

No mutagenic activity was observed.