The NTP has published two final reports, on the long-term toxicology, genotoxicity and carcinogenicity of antimony trioxide, and on the subchronic toxicity of chitosan.

In lifetime studies, rats and mice were exposed to atmospheres containing aerosolised antimony trioxide, at concentrations of 3, 10 or 30 mg/m3, for 6 hours/day, 5 days/week for 2 years. There was “clear evidence of carcinogenic activity” in male and female rats, on the basis of increased incidences of malignant lung tumours and, in females, malignant lymphoma. There was “some evidence of carcinogenic activity” in male and female mice, with increased incidences of tumours in the lungs and adrenal medulla reported. A range of non-neoplastic lesions were observed in all treated animals. There was also evidence in treated mice of DNA damage in the lung cells, and micronucleated erythrocyte formation in the peripheral blood. No genotoxic effects were reported for treated rats.

Chitosan was administered to rats at dietary concentrations of 1%, 3% or 9% (up to 5200 mg/kg bw/day for males and 6000 mg/kg bw/day for females) for 6 months. Such exposure caused “decreased fat digestion and depletion of some fat-soluble vitamins” in the treated animals.

US National Toxicology Program (2017). Technical Report on the toxicology and carcinogenesis studies of antimony trioxide (CAS No. 1309‑64-4) in Wister Han Rats and B6C3F1/N mice (inhalation studies). NTP TR 590. December 2017. https://ntp.niehs.nih.gov/ntp/htdocs/lt_rpts/tr590_508.pdf

Technical Report on the toxicity study of chitosan (CAS No. 9012-76-4) administered in feed to Sprague Dawley rats. NTP TOX 93. December 2017. https://ntp.niehs.nih.gov/ntp/htdocs/st_rpts/tox093_508.pdf

 

The above items were taken from the January-February 2018 issue of Toxicology and Regulatory News which is sent automatically to members of bibra.

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