Determination of Cetirizin in Human Plasma by LC-MS

OBJECTIVE:To develop an LC-MS method for the determination of plasma concentration of cetirizin.MET-HODS:Plasma sample(0.5 mL) was detected after liquid-liquid extraction with acetic ether-dichloromethane(41).The mobile phase consisted of acetonitrile-water(0.1% formic acid)(5545) at a flow rate of 0.5 mL·min-1.An agilent 1100 tandem mass spectrometer equipped with ESI source was used as detector and was operated in positive ion mode.Selected reaction monitoring(SRM) using the precursor product ion combinations of m/z 389→201 and m/z 515→497 were used to quantify cetirizin and telmisartan(internal standard),respectively.RESULTS:The linear concentration range of cetirizin was 2.5～400 μg·L-1(r=0.999 3).The low limit of quantification was 2.5 μg·L-1.The intra-day and inter-day RSD were all no more than 9.9%.The analyzing time for each sample was less than 2.8 min.CONCLUSION:The method was proved to be rapid,sensitive and suitable for the pharmacokinetic study of cetirizin.