Titanium nitride

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

The results from a bioelution assay demonstrated low titanium release from titanium nitride in simulated gastric fluid. Therefore, low bioavailability can be expected via the oral route.

In a read-across study, titanium dioxide did not show adverse effects after chronic oral repeated dose exposure in reproductive organs mice and rats.

In addition, the results from the bioelution tests with TiN together with the very low solubility of the test material in a transformation/dissolution test lead to the conclusion that no to very low bioavailability can be expected via the inhalation and dermal route.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reproductive effects observed:

not specified

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

No substance-specific data on toxicity to reproduction is available for titanium nitride. Bioelution results of titanium nitride in four artificial body fluids which served as a surrogate for bioavailability in different tissues, demonstrated very low release of titanium ions in general (Cappellini D., 2015, see IUCLID section 7.1.1). The amount of soluble titanium was below detection limit after short-term incubation in artificial perspiration fluid and both short and long-term incubation in simulated interstitial fluid, representing dermal/sweat and interstitial milieus in the deep lung, respectively. Very limited amounts of soluble titanium could be detected in artificial lysosomal fluid (0.11% titanium release after 24 hours) and simulated gastric fluid (2.34% titanium release after 24 hours). Based on these results, very limited absorption and systemic distribution can be expected and an exposure of the reproductive organs in male and female rats to titanium nitride is rather unlikely. Thus, any specific effects on reproduction are not to be expected.

This assumption is supported by investigations during a chronic repeated dose toxicity read-across study via the oral route in mice and rats with titanium dioxide. No adverse effects and no effects on reproductive organs including uterus, testes, ovaries and mammary gland were observed after a treatment period of 103 weeks at dietary levels up to 50,000 ppm (equivalent to 6,500 mg/kg bw/day in mice and 2,500 mg/kg bw/day in rats). These concentrations largely exceed the maximum recommended concentration in the reproductive and developmental toxicity screening study (1,000 mg/kg bw/day). For the reasons presented above, conducting a reproduction and developmental toxicity screening study will therefore not provide any further insights in the toxicity of titanium nitride. Therefore, and especially in light of animal welfare, it is scientifically not justified to conduct a further reproductive and developmental toxicity screening study in rats (in accordance with Annex X, section 8.7, column 2 of Regulation (EC) 1907/2006).

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

No substance-specific data on toxicity to reproduction is available for titanium nitride.

Bioelution results of titanium nitride in four artificial body fluids which served as a surrogate for bioavailability in different tissues, demonstrated very low release of titanium ions in general.

The amount of soluble titanium was below detection limit after short-term incubation in artificial perspiration fluid and both short and long-term incubation in simulated interstitial fluid, representing the lung and interstitial milieus, respectively. Very limited amounts of soluble titanium could be detected in artificial lysosomal fluid (0.11% titanium release after 24 hours) and simulated gastric fluid (2.34% titanium release after 24 hours). Based on these results, very limited absorption and systemic distribution can be expected and an exposure of the reproductive organs in male and female rats to titanium nitride is rather unlikely. Thus, any specific effects on reproduction are not to be expected.

This assumption is supported by investigations during a chronic repeated dose toxicity read-across study via the oral route in mice and rats with titanium dioxide.

No adverse effects and no effects on reproductive organs including uterus, testes, ovaries and mammary gland were observed after a treatment period of 103 weeks at dietary levels up to 50,000 ppm (equivalent to 6,500 mg/kg bw/day in mice and 2,500 mg/kg bw/day in rats). These concentrations largely exceed the maximum recommended concentration in the reproductive and developmental toxicity screening study (1,000 mg/kg bw/day).

For the reasons presented above, conducting a reproduction and developmental toxicity screening study will therefore not provide any further insights in the toxicity of titanium nitride. Therefore, and especially in light of animal welfare, it is scientifically not justified to conduct a further reproductive and developmental toxicity screening study in rats (in accordance with Annex X, section 8.7, column 2 of Regulation (EC) 1907/2006).

Justification for classification or non-classification

Based on the results of a bioelution assay in different simulated body fluids and solubility data for the test item titanium nitride, no to low systemic bioavailability can be expected.

Therefore, exposure of the reproductive organs in male and female rats to titanium nitride is rather unlikely. Thus, any specific effects on reproduction are not to be expected and classification for Reproductive toxicity according to Regulation (EC) 1272/2008 is not warranted.