Zirconium carbide

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-10-08 to 2014-02-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Objective of study:

bioaccessibility (or bioavailability)

Qualifier:

no guideline followed

Principles of method if other than guideline:

This report measured bioaccessibility of Zirconium carbide in body fluid simulants as a surrogate for bioavailability.

GLP compliance:

no

Radiolabelling:

no

Species:

other: not applicable

Strain:

other: not applicable

Sex:

not specified

Details on test animals or test system and environmental conditions:

not applicable

Route of administration:

other: not applicable

Vehicle:

other: not applicable

Details on exposure:

not applicable

Duration and frequency of treatment / exposure:

not applicable

Remarks:

0.1 g of test substance in 50 mL of simulated fluid

No. of animals per sex per dose / concentration:

not applicable

Control animals:

other: not applicable

Positive control reference chemical:

not applicable

Details on study design:

Please see box "Any other information on materials and method incl. tables"

Details on dosing and sampling:

not applicable

Statistics:

not applicable

Preliminary studies:

not applicable

Details on absorption:

not applicable

Details on distribution in tissues:

not applicable

Details on excretion:

not applicable

Metabolites identified:

not measured

Details on metabolites:

not applicable

Bioaccessibility (or Bioavailability) testing results:

The results of the bio-elution tests (see Table 1 in box "Any other information on results incl. tables") of Zirconium carbide in general showed a very low solubility in the set of fluids assayed.

Table 1: Results of bio-elution tests

Extraction Time	Weight Used (g)	µg Zirconium / g Sample	% Zirconium Release/ Zirconium Content
Simulated Gastric Fluid
2 hours	0.1004	<25.0	---
(dup)	0.1008	<25.0	---
24 hours	0.1001	<25.0	---
(dup)	0.1006	<25.0	---
Simulated Interstitial Fluid
2 hours	0.1016	<25.0	---
(dup)	0.1016	<25.0	---
24 hours	0.1005	<25.0	---
(dup)	0.1016	<25.0	---
Simulated Lysosomal Fluid
2 hours	0.1002	35.0	0.004
(dup)	0.1008	<25.0	---
24 hours	0.1012	40.0	0.005
(dup)	0.1028	39.0	0.005
Artificial Perspiration
2 hours	0.1001	<25.0	---
(dup)	0.1008	<25.0	---
24 hours	0.1009	<25.0	---
(dup)	0.1005	<25.0	---
PBS
2 hours	0.1006	<25.0	---
(dup)	0.1009	<25.0	---
24 hours	0.1003	<25.0	---
(dup)	0.1004	<25.0	---

Conclusions:

The release of zirconium ions from Zirconium carbide was very low in artificial body fluids. For simulated gastric fluid, simulated interstitial fluid and arteficial perspiration no release of zirconium ions was observed as the results were below the detection limit of the method. Only in simulated lysosomal fluid 0.005% zirconium ions were released within 24 hours from Zirconium carbide.

Executive summary:

This report measured bioaccessibility of Zirconium carbide as a surrogate for bioavailability. Thus, the soluble zirconium was measured by using EPA Method #200.8 (ICP/MS) after incubation of Zirconium carbide in different simulated body fluids (simulated gastric fluid, simulated interstitial fluid, simulated lysosomal fluid, and artificial perspiration). Results were reported as µg Zr/g sample, % Zr release/Zr content. The release of zirconium ions from Zirconium carbide was very low in artificial body fluids. The results of the study are summarized in the table below:

Extraction Time	Weight Used (g)	µg Zirconium / g Sample	% Zirconium Release/ Zirconium Content
Simulated Gastric Fluid
2 Hours	0.1004	<25.0	---
(dup)	0.1008	<25.0	---
24 Hours	0.1001	<25.0	---
(dup)	0.1006	<25.0	---
Simulated Interstitial Fluid
2 Hours	0.1016	<25.0	---
(dup)	0.1016	<25.0	---
24 Hours	0.1005	<25.0	---
(dup)	0.1016	<25.0	---
Simulated Lysosomal Fluid
2 Hours	0.1002	35.0	0.004
(dup)	0.1008	<25.0	---
24 Hours	0.1012	40.0	0.005
(dup)	0.1028	39.0	0.005
Artificial Perspiration
2 Hours	0.1001	<25.0	---
(dup)	0.1008	<25.0	---
24 Hours	0.1009	<25.0	---
(dup)	0.1005	<25.0	---
PBS
2 Hours	0.1006	<25.0	---
(dup)	0.1009	<25.0	---
24 Hours	0.1003	<25.0	---
(dup)	0.1004	<25.0	---

Description of key information

The release of zirconium ions from Zirconium carbide was very low in artificial body fluids. For simulated gastric fluid, simulated interstitial fluid and artificial perspiration no release of zirconium ions was observed as the results were below the detection limit of the method. Only in simulated lysosomal fluid 0.005% zirconium ions were released within 24 hours from Zirconium carbide.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Additional information

The bioaccessibility of Zirconium carbide as a surrogate for bioavailability was measured. For this purpose soluble zirconium ions were measured using the EPA method #200.8 (ICP/MS) after incubation of Zirconium carbide in different simulated body fluids (simulated gastric fluid, simulated interstitial fluid, simulated lysosomal fluid and artificial perspiration).

In summary, in all body fluids the release of zirconium ions was below the detection limit of the methodology used, except for the simulated lysosomal body fluid, in which the release of zirconium was measured with 0.005%. Based on the results, the bioavailability of Zirconium carbide can be considered to be very low for all routes of administration.