A novel LC-MS/MS approach to the pharmacokinetic study of free and bound aflibercept simultaneously.

To comprehensively evaluate the pharmacokinetic (PK) characteristics of aflibercept, we established a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to determine the concentration of vascular endothelial growth factor (VEGF)-A-bound aflibercept and free aflibercept. A specific sample preparation method of nano-surface and molecular-orientation limited (nSMOL) proteolysis was performed to extract both free and bound aflibercept from plasma. The tryptic peptides unique to aflibercept and VEGF-A were selected to quantify the amounts of total aflibercept and aflibercept-VEGF complex, respectively.

Simultaneous quantification of Kirenol and ent-16β,17-dihydroxy-kauran-19-oic acid from Herba Siegesbeckiae in rat plasma by liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies.

A rapid and specific liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed for the simultaneous determination of two active diterpenoids: Kirenol and ent-16β,17-dihydroxy-kauran-19-oic acid (DHKA) from Herba Siegesbeckiae in rat plasma using osthole as an internal standard (IS). Plasma sample pretreatment involved a one-step liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a Waters Symmetry C18 column (2.

Simultaneous determination of seven major diterpenoids in Siegesbeckia pubescens Makino by high-performance liquid chromatography coupled with evaporative light scattering detection.

A novel HPLC method with evaporative light scattering detection was developed for the simultaneous quantification of seven major diterpenoids of two types, including ent-pimarane type: Kirenol, Hythiemoside B, Darutigenol, and ent-kaurane type: ent-16β,17,18-trihydroxy-kauran-19-oic acid, ent-17,18-dihydroxy-kauran-19-oic acid, ent-16β,17-dihydroxy-kauran-19-oic acid, 16α-hydro-ent-kauran-17,19-dioic acid in the aerial parts of Siegesbeckia pubescens Makino, an important traditional Chinese medicinal herb. Chromatographic separation was achieved on a Waters Symmetry Shield(TM) RP18 column (250 mm× 4.6 mm id, 5 μm) with a gradient mobile phase (A: 0.