In vitro Investigation of Metabolic Profiling of a Potent Topoisomerase Inhibitors Fluorescein Hydrazones (FLHs) in RLMs by LC-MS/MS.

Metabolic profiling of newly reported two topoisomerase inhibitors namely fluorescein hydrazones (FLHs) were studied in rat liver microsomes (RLMs) and the data were acquired in a liquid chromatography (LC) ion trap mass spectrometry. (E)-3',6'-dihydroxy-2-((2-nitrobenzylidene)amino)spiro[isoindoline-1,9'-xanthen]-3-one (1) was bio-transformed into two mono-hydroxylated, one double hydroxylated and a tetra hydroxylated metabolites, on the other hand, (Z)-3',6'-dihydroxy-2-((2-oxoindolin-3-ylidene)amino)spiro[isoindoline-1,9'-xanthen]-3-one (2) was bio-transformed into eight possible metabolites by cleavage reduction, hydroxylation, cleavage reduction together with hydroxylated and azo-reduction in RLMs in presence of NADPH-generating system. No metabolites were generated in the absence of either NADPH or microsomes for the compounds (1 and 2), indicating a likely involvement of CYP450 enzymes and the cofactor NADPH in the metabolisms. The structures of those metabolite were elucidated by MS/MS fragmentation study.