Abstract
Excretion and distribution of sizofiran (SPG), an antitumor polysaccharide, were investigated after a single intravenous (i.v.) injection of 14C-labelled SPG(14C-SPG) to rats. Radioactivity was very slowly eliminated from the body. It was mainly excreted in the urine. When 14C-SPG was given at doses of 0.2mg and 2 mg/kg, the radioactivity recovered in the urine within 6 months was 41% and 26%, respectively. Radioactivity much less than urinary excretion was also observed in the feces and expired gas. In whole-body autoradiographic study, radioactivity was distributed selectively in the reticuloendotherial tissues such as liver, spleen, mesenteric lymph node and bone marrow at 24 h after dosing, and still remained to be considerably high in the spleen, lymph node, liver and thymus at six months after dosing. SPG-like substances, isolated from the livers, spleens and mesenteric lymph nodes of rats given non-radioactive SPG, seemed to have a similar chemical structure to that of SPG and were shown to have a similar potent antitumor activity to that of SPG against sarcoma-180 murine tumor.
