Objectives: Triptolide (TPL) has been shown to have a good clinical effect on rheumatoid arthritis (RA). We
designed TPL microspheres (TPL-MS) and investigated its metabolic behavior in human, dog, rabbit and rat liver
microsomes (HLM, DLM, RLM and SDRLM) with UPLC-MS/MS method.
Methods: First, a UPLC-MS/MS method was established to measure concentration of TPL in samples. The sample was
separated on a C18 column (2.1×100 mm, 1.8μm) and eluted with a gradient elution. The precursor ion/product ion were
m/z 378.1/361.0 for TPL and 260.0/116.2 for the internal standard. Then T1/2, Vmax and CLint were calculated from the above
data. Finally, the metabolites of TPL-MS were identified by high-resolution UPLC-MS/MS. The sample was separated on
a C18 column (2.1×100 mm, 2.2 μm) and eluted with isocratic elution. Mass spectrometric detection was carried out on a
thermo Q-exactive mass spectrometer with HESI. The scanning range of precursor ions was from m/z 50 to m/z 750.
Result and Discussion: Through several indicators including standard curve, precision, accuracy, stability, matrix effect
and recovery rate, the enzymatic kinetics parameters including T1/2, Vmax and CLint were completed. Several metabolites of
TPL-MS were identified.
Conclusion: UPLC-MS/MS method is an accurate and sensitive method for determination of TPL in liver microsome
samples with good precision, accuracy and stability. The variation of parameters indicated that the microspheres can delay
the elimination of TPL in liver microsomes. The metabolism of TPL-MS varied among species, but no new metabolites