Tentative identification of in vitro metabolites of 5-APDB, a synthetic benzofuran, by LC-Q/TOF-MS.

5-(2-Aminopropyl)-2,3-dihydrobenzofuran (5-APDB) is a designer drug of phenethylamine and amphetamine class. In this study, the in vitro metabolism of 5-APDB was investigated in rat and human liver microsomes and human hepatocytes to characterize its metabolites. 5-APDB was incubated with microsomes or hepatocytes, and the reaction mixture was analyzed using liquid chromatography-quadrupole time-of-flight with tandem mass spectrometry (LC-Q/TOF-MS). 5-APDB was metabolized to yield three metabolites (M1, M2 and M3). These metabolites were structurally characterized on the basis of accurate mass analysis and MS/MS fragmentation patterns. Metabolite M1 and M2 were identified as hydroxylated metabolites in the benzofuran moiety; M3 was a reduced metabolite which may be generated from M1 or M2 via dehydration. These results provide evidence for the in vivo 5-APDB metabolism, and would be forensically useful for the detection of 5-APDB and its metabolites in biological samples.