ABSTRACT
Objective To establish a rapid LC-MS/MS method for the simultaneous quantitative determination of lopinavir (LPV)and ritonavir(RTV)in human plasma. Methods Plasma samples were prepared by protein precipitation and separated by a Thermo Hypersil GOLD column(2.1 mm×100 mm,5 mm)with the mobile phase consisting of methanol and water(0.1%formic acid) at a flow rate of 0.2 ml/min. Detection of LPV,RTV and the internal standard(IS)MS 275 was performed using selected reaction moni?toring(SRM)of the transitions m/z 629.3→155.0,m/z 721.3→268.0 and m/z 377.1→359.2 in positive ion mode,respectively. Re?sults The calibration curve was linear in the range of 20-1000 ng/ml(r>0.994)for LPV and RTV. The intra and inter-day precision and accuracy values met the set acceptance criteria. Conclusion The method is rapid,sensitive and accurate for the therapeutic drug monitoring of LPV and RTV simultaneously in clinic and pharmacokinetic studies.
ABSTRACT
Objective To develop a sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of forsklin in rat plasma.Methods After extraction with methyl tert-butyl ether,chromatographic separation was performed on a C18 column with the mobile phase consisting of water ( 0.1％ formic acid)-acetonitrile in a gradient elution mode.A tandem mass spectrometer equipped with electrospray ionization (ESI) source was used as detector in the positive ion mode.Quantification was performed using multiple reaction monitoring (MRM) with the precursor product combination ions of m/z 411→375.3 and 285→193 for forsklin and diazepam.Results Good linearity was obtained in the 0.5-1000 ng/ml range for the analyte and the analytical method was validated in terms of specificity,precision,accuracy,recovery,stability and matrix effect.These assays gave RSD values always lower than 14.4％ and RE values between -3.5 ％ and 3.8％.In addition,the specificity,extraction recovery,stability and matrix effect were satisfactory.Conclusion Due to its high sensitivity,specificity and simplicity,the method could be used for pharmacokinetic studies of forsklin.