Hydroxylapatite (Ca5(OH)(PO4)3)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test substance is not mutagenic under this test conditions.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Hydroxyapatite with zirconia added (to make it tougher), whitish grey fine powder, aseptic precautions taken when handling the substance

Species / strain / cell type:

other: S. typhimurium TA98, TA100, TA1535, TA1537 and E.coli WP2uvrA

Metabolic activation:

with and without

Metabolic activation system:

S9-Mix

Test concentrations with justification for top dose:

5000, 2500, 1250, 625 and 313 µg/plate
top dose according to guideline for non-cytotoxic substances, cytotoxicity tested (= not cytotoxic)

Untreated negative controls:

no

Remarks:

water

Positive controls:

yes

Positive control substance:

other: 2-(2-Furyl)-3(5-nitro-2-furyl)acrylamide, Sodium azide, 2-d-2-Aminoanthracene, Methoxy-6-chloro-9(3-(2-chloroethyl)-aminopropylamino)acrinidine

Details on test system and experimental conditions:

pre-incubation method
negative control: triplicate, positive controls and treatment: duplicate, control for bacterial contamination of the agar plates: once

Rationale for test conditions:

according to guideline

Evaluation criteria:

number of revertant colonies equal or less than negative control, reproducible effects (duplicates),no concentration-dependent effects

Statistics:

The colonies were counted with a manual counter or a colony analizer. Each plate was counted 3 times and the mean was given. The average plate count for each dose was calculated as the average of the duplicates.

Key result

Species / strain:

other: S. typhimurium TA98, TA100, TA1535, TA1537 and E.coli WP2 uvrA

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:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: no mutagenic potential

Conclusions:

The test substance is not mutagenic under this test conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

The test item is not genotoxic under the conditions of this test.

Link to relevant study records

Reference

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

other: Bone Marrow Abberation Test

Species:

mouse

Strain:

other: Swiss Albino Strain

Sex:

male/female

Details on test animals or test system and environmental conditions:

Source: Animal House Unit of the USM Health Campus
adult, healthy mice (10-12 weeks old), body weights: females: 29.51+/-0.22g, males: 36.28+/-0.37g
reared in cages, comercial pellet diet and distilled water ad libitum

Route of administration:

intraperitoneal

Vehicle:

distilled water

Duration of treatment / exposure:

6, 24, 48 hours

Frequency of treatment:

once

Post exposure period:

90 min. before sacrifice: intraperitoneally injection of caochicine (4mg/kg)

Remarks:

2000mg/kg body weight (synthetic hydroxyapatite granules, porous form, 100 - 200 microns in size, dispersed in 0.5ml of distilled water)

No. of animals per sex per dose:

5 females + 5 males per dose, 3 doses
+ negative control group + positive control group

Control animals:

yes

yes, concurrent vehicle

Positive control(s):

Mitomycin C (1.5 mg/kg bw), killed 24 hours after treatment

Tissues and cell types examined:

bone marrow from both femurs

Details of tissue and slide preparation:

The cells were flushed in water, centrifuged, fixed on slides and stained with Leishman's stain in phosphate buffered saline. A total of 100 metaphase cells per animal were scored under a microscope for chomosomal abberations, documented by photographs. Then the mitotic index as mean of 10 animals was calculated.

Statistics:

mean values, standard errors and satistical evaluation following ANOVA tset and subsequent comparing with Duncan's newe multiple range test values

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

The teswt subsstance is not genotoxic under the conditions of this test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Nanoparticles of hydroxyapatite have sub-lethal toxic effects on fish cells and fish embryos. The effects of neddles is stronger.