Trisilicon tetranitride

Endpoint summary

Description of key information

From the data available so far there is no evidence that the test substance is absorbed via the gastrointestinal tract following oral (or inhalation) administration or via the skin following dermal administration.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

No specific study was performed on the absorption / distribution / metabolism / excretion (ADME) of this substance (Silicon Nitride) but data are currently available from the in vivo toxicology studies.

 

Absorption

Due to the physicochemical properties of Silicon Nitride and its low water solubility it is not expected to be well absorbed although a low molecular weight may favour absorption. 

Oral route

During acute oral studies in rats all behavioural, clinical and physiological responses after administration were considered normal. The oral LD50 for Silicon Nitride was >2000 mg/kg body weight in male and female rats. Without pharmacokinetic data it is difficult to say if absorption occurred in these studies.

 

In a repeat dose (28-day) study no toxicologically significant adverse systemic effects were noted in either male or female rats at dose levels up to 1000 mg/kg/day.

 

In a reproductive screening test no toxicological effects were noted and there was no effect of treatment on reproductive performance or development of the fetus, including mating performance, fertility and offspring survival and development up to Day 4 of age, at dose levels up to 1000 mg/kg/day.

Dermal route

An acute dermal study was not performed as this was not considered to be an appropriate route of exposure. 

A skin sensitisation study in mice (LLNA assay) showed that Silicon nitride was not regarded as a potential skin sensitiser. Similarly skin irritation and eye irritation studies in rabbits showed that no symptoms of systemic toxicity or deaths were seen and Silicon Nitride is not considered to be a skin irritant or eye irritant.

 

Inhalation route

An acute inhalation (4 hour exposure) study was performed in male and female rats, all animals survived the study and no toxicological effects were noted

 

Distribution

The lack of toxicologically significant findings from the acute, repeat and reprotoxicity studies all provide evidence that the test substance is not absorbed from the gastrointestinal tract or lungs and that there is no evidence of systemic distribution.

Metabolism

No data are available on metabolism in the existing toxicity studies.

 

Excretion

No data are available on excretion in the existing toxicity studies. 

Conclusion

From the data available so far there is no evidence that the test substance is absorbed via the gastrointestinal tract following oral (or inhalation) administration or via the skin following dermal administration.