No toxicological effects on acute and repeated oral gavage doses of single-wall or multi-wall carbon nanotube in rats.
Three female Crl:CD(SD) rats/group were dosed with single wall carbon nanotube (SWCNT) or multi wall carbon nanotube (MWCNT) four times by gavage at a total of 50 mg/kg bw or 200 mg/kg bw (four equally divided doses at one-hour intervals). Acute oral doses of SWCNT and MWCNT  caused neither death nor toxicological effects, and thus the oral LD<inf>50 </inf>values for SWCNT and MWCNT  were considered to be greater than 50 mg/kg bw and 200 mg/kg bw, in rats respectively. Five or ten Crl:CD(SD) rats/sex were dosed with SWCNT once daily by gavage at a dose of 0 (control), 0.125, 1.25 or 12.5 mg/kg bw/day for 28 days with a 14-day recovery period (0 and 12.5 mg/kg bw/day groups). Six or twelve Crl:CD(SD) rats/sex were dosed with MWCNT once daily by gavage at a dose of 0 (control), 0.5, 5.0 or 50 mg/kg bw/day for 28 days with a 14-day recovery period (0 and 50 mg/kg bw/day groups). Based on no toxicological effects, the no observed adverse effect levels (NOAELs) of repeated dose toxicity of SWCNT and MWCNT were considered to be 12.5 mg/kg bw/day and 50 mg/kg bw/day (the highest dose tested), respectively. It was suggested that SWCNT and MWCNT dosed by gavage reached the gastro-intestinal tract as agglomerates and were mostly excreted via feces.
Division of Risk Assessment, Biological Safety Research Center, National Institute of Health Sciences, Tokyo, Japan.
Mariko
M
Matsumoto
Hideki
H
Serizawa
Masao
M
Sunaga
Hina
H
Kato
Mika
M
Takahashi
Mutsuko
M
Hirata-Koizumi
Atsushi
A
Ono
Eiichi
E
Kamata
Akihiko
A
Hirose
D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D007928:Lethal Dose 50; D008297:Male; D037742:Nanotubes, Carbon / Q000633:toxicity*; D019055:No-Observed-Adverse-Effect Level; D010316:Particle Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D023382:Toxicity Tests, Acute / Q000379:methods*
D037742:Nanotubes, Carbon