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Administrative data

Description of key information

A 28-day repeat dose oral toxicity study in rats resulted in a NOAEL of 1000 mg/kg/day.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

A subacute oral toxicity study was conducted (Nihon Bioresearch Inc, 2002) to assess the systemic toxicity of Silicon Nitride in the rat, over 28 days treatment by repeated once daily administration. A subsequent 14 -day recovery period was allowed for selected animals to assess the potential for reversibility of any treatment-related changes. Silicon Nitride was administered by oral gavage in 0.5% sodium carboxymethylcellulose in water, once daily, to four groups of 12 male and 12 female rats for up to twenty-eight consecutive days at dosage levels of 0, 100, 300 or 1000 mg/kg/day. No dead or moribund animals were observed in any group. No general abnormalities were observed in any group. No treatment-related changes were seen in body weight, food or water consumption, urinalysis, haemotology, blood biochemistry, necropsy findings, organ weights or histopathology. Based on these findings, Silicon Nitride was considered to show no toxicological effects in either male or female rats at up to 1000 mg/kg. As a result the NOEL of Silicon Nitride was considered to be 1000 mg/kg for male and female rats under the conditions of the study.


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
This key study was conducted to OECD guideline 407.

Justification for classification or non-classification

A subacute 28 -day repeat oral dose study in rats was conducted and the NOEL was found to be 1000 mg/kg/day. Silicon Nitride is therefore not classified as toxic to health by prolonged exopsure by the oral route.