Simultaneous determination of phenolic acids by UPLC–MS/MS in rat plasma and its application in pharmacokinetic study after oral administration of Flos Lonicerae preparations

The current study aims to investigate the pharmacokinetic study of five phenolic acids (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid) following oral administration of Flos Lonicerae preparations in rats. A rapid and sensitive ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed to simultaneously determine the five phenolic acids in rat plasma. After mixing with the internal standard (IS) tinidazole, plasma samples were pretreated by liquid–liquid extraction with ethyl acetate/n-hexane (9:1, v/v). The separation was performed on an Acquity UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 μm) at a flow rate of 0.4 ml min(−1), and acetonitrile/methanol (4:1, v/v)-0.4% formic acid was used as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization (ESI) source with positive ionization mode. All calibration curves had good linearity (r > 0.991) over the concentration ranges of 0.74–378 ng ml(−1) for neochlorogenic acid, 0.50–1030 ng ml(−1) for chlorogenic acid, 1.9–250 ng ml(−1) for cryptochlorogenic acid, 0.74–380 ng ml(−1) for 3,5-dicaffeoylquinic acid, and 5.1–328 ng ml(−1) for 3,4-dicaffeoylquinic acid. The intra-and inter-day precision were within 15% and the accuracy ranged from 86.2% to 114.1%.