Metabolism of TM-2, a potential antitumor drug, in rats by using LC-MS

TM-2 (13-(N-Boc-3-i-butylisoserinoyl-4,10-β-diacetoxy-2-α-benzoyloxy-5-β-20-epoxy-1,13-α-dihydroxy-9-oxo-19-norcyclopropa[g]tax-11-ene) is a novel semisynthetic taxane derivative. Our previous study suggested that TM-2 is a promising antitumor analogue. In this paper, the metabolism of TM-2 was investigated in rats following intravenous administration. Two different types of mass spectrometry-hybrid linear trap quadrupole orbitrap (LTQ-Orbitrap) mass spectrometry and triple-quadrupole tandem (QQQ) mass spectrometry-were employed to acquire structural information of TM-2 metabolites. A total of 17 components were identified as the metabolites of TM-2 in bile, feces, and urine samples. Accurate mass measurement using LC-LTQ-Orbitrap-MS was used to determine the accurate mass data and elemental composition of metabolites thereby confirming the proposed structures of the metabolites. The metabolites proposed were mainly oxidates of TM-2, including methoxy, hydroxyl, dihydroxy, and trihydroxyl analogues. The major metabolic pathway of TM-2 was the hydroxylation of the taxane ring or the lateral chain. These important metabolic data serve as a useful resource to support further research of TM-2.