Time-dependent variation in the biodistribution of C60 in rats determined by liquid chromatography–tandem mass spectrometry

Abstract

We examined the biodistribution of C60 in rats after tail vein administration using LC–MS/MS. C60 was detected in various tissues, such as brain, kidneys, liver, lungs, and spleen of rats. On the other hand, no C60 was found in blood. The highest C60 concentration was observed in the lungs, followed by spleen, liver, kidneys, and brain. These results suggested that C60 injected in the tail vein could be filtered by lung capillary vessels and accumulate in the lungs prior to being distributed to other tissues. Moreover, C60 not being detected in the blood indicates that clearance of C60 from the blood by filtration might effectively occur in the lungs. The time-dependent variation in the biodistribution of C60 was evaluated. A time-dependent decrease in C60 concentrations was observed in all tissues, except spleen. Moreover, a decreasing trend of C60 levels differed among tissues, which could be due to differences in accumulation. These results suggest that unmodified C60 and/or C60 metabolites by metabolic enzymes could be excreted into feces and/or urine. In further studies, the metabolic and excretion pathways of C60 should be evaluated to understand the toxicokinetics of C60.