Quantitative determination of 2-amino-2-(2-(4'-(2-propyloxazol-4-yl)-[1,1'-biphenyl]-4-yl)ethyl)propane-1,3-diol and its active phosphorylated metabolite in rat blood by LC-MS/MS and application to PK/PD analysis.

A sensitive and specific LC-MS/MS method was developed and validated for simultaneous determination of 2-amino-2-(2-(4'-(2-propyloxazol-4-yl)-[1,1'-biphenyl]-4-yl)ethyl)propane-1,3-diol (SYL930) and its active phosphate metabolite (SYL930-P) in rat blood using SYL927, an analogue of SYL930 as the internal standard. Blood samples were prepared by a simple protein precipitation with acetonitrile. The chromatographic separation was performed on a ZorbaxSB-C18 column (3.5 μm, 2.1 × 100 mm) with a gradient mobile phase of methanol/water containing 0.1 % formic acid (v/v) at a flow rate of 0.2 mL/min. The detection was carried out on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) in multiple reactions monitoring mode (MRM). The monitored transitions were 381.2 → 364.2 for SYL930, 461.2 → 334.2 for SYL930-P, and 367.1 → 350.4 for the internal standard, respectively. Good linearity was obtained for the analytes over the range of 0.2-100 ng/mL for SYL930 and 0.5-100 ng/mL for SYL930-P. The lower limits of quantitation (LLOQs) for SYL930 and SYL930-P were 0.2 and 0.5 ng/mL, respectively. The intra-day and inter-day precisions (RSD, %) of analytes were within 9.87 %, and the accuracy (RE, %) ranged from -7.04 to 13.15 %. The mean recoveries for two compounds in rat blood were 87.9-109 %. The analytes were proved to be stable during all sample storage, preparation, and analytic procedures. The validated method was successfully applied to pharmacokinetic and PK/PD studies of SYL930 and SYL930-P in rats after oral administration of SYL930. Graphical Abstract Quantitative determination of SYL930 and its active phosphorylated metabolite in rat blood by LCMS/MS and application to PK/PD analysis.