A rapid and sensitive supercritical fluid chromatography/tandem mass spectrometry method for detection of ezetimibein dog plasma and its application in pharmacokinetic studies.

The aim of this study is to develop and validate a rapid, high-selective and sensitive supercritical fluid chromatography/tandem mass spectrometry (SFC-MS/MS) with a multiple reactions monitoring (MRM) mode method for the detection of ezetimibe in dog plasma. Several conditions were optimized systematically as follows: lipid-lipid extraction (LLE) performances were used to extract analytes from dog plasma; an ACQUITY HSS C SB (1.8 μm, 3.0 × 100 mm) column was employed to separate the target compounds; the triple-quadrupole mass spectrometry equipped with electrospray ionization (ESI) source was applied to detect ezetimibe. The method, which required a relatively small volume of plasma (100 μL), was obtained at concentration ranging from 1.0 to 100 ng/mL(r > 0.99). The lower limit of quantification (LLOQ)for ezetimibe was found to be as low as 1.0 ng/mL. In addition, the validations of the methodology including sensitivity, recovery, matrix effect, intra- and inter-day precision, accuracy and stability were all within acceptable limits. The C, AUC and T values obtained in our study were 52.2 ± 6.3, 820.6 ± 4.3 and 1.25 ± 0.35 for reference formulation; 61.8 ± 12.6, 924.2 ± 4.7 and 2.00 ± 0 for test formulation. In conclusion, the method developed in this study can be successfully applied to pharmacokinetic studies after oral administration of ezetimibe in dogs.