Simultaneous determination of TPN729 and its five metabolites in human plasma and urine by liquid chromatography coupled to tandem mass spectrometry.

A specific and sensitive method was firstly developed using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) to simultaneously quantify TPN729 and its metabolites (TPN729-D1, TPN729-D2, TPN729M15-3 and TPN729M3) in human plasma and (TPN729-D1, TPN729-D2, TPN729M15-3 and TPN729M14) in human urine. Protein precipitation and direct dilution were used to extract TPN729 and its metabolites from plasma and urine, respectively. Ionization of TPN729, TPN729-D1, TPN729-D2, TPN729M15-3, TPN729M3, TPN729M14 and sildenafil (internal standard, IS) was performed using an electrospray ionization (ESI) source in positive mode and detection was carried out with multiple reaction monitoring (MRM) mode.