Absorption of m-AMSA and its biliary metabolites from the rat small intestine

Abstract The ability of orally administered m-AMSA (NSC- 249992 ) to be absorbed was examined in the rat. Studies using isolated in situ intestinal loops showed that m-AMSA (25 μM) was absorbed equally well in jejunum and ileum and that absorption was 50% complete in 5–10 min and 90% complete by 60 min . In the intact rat, orally administered m-AMSA was found to be 93% absorbed at a dose of 50 mg/kg and 82% absorbed at a dose of 200 mg/kg . Absorption was measured 8 hr after dosing. m-AMSA biliary metabolites were found to be poorly absorbed by the gut. Following a dose of m-AMSA ( 10 mg/kg , i.v.), rats were observed for 4 hr and less than 10% of the available m-AMSA biliary metabolite was absorbed. Enterohepatic circulation of m-AMSA appears to be insignificant.