Rapid Determination of Methadone in Human Plasma by LC-MS/MS / 中国药房

ABSTRACT

OBJECTIVE:To set up a LC-MS/MS method for determination of plasma concentration of methadone.METHODS:Methadone was extracted with ethyl acetate and dichloromethane(4∶1)and the residues were analyzed with a LC-MS/MS system using Agilent TC C18 column at a column temperature of 25 ℃ with the mobile phase consisted of methanol-5 mmol?L-1 ammonium formate(90∶10)at a flow rate of 1 mL?min-1.An agilent 6410 triple quad mass spectrometer system equipped with an electrospray ionization ion-trap source was used as the detector and operated in the positive ion mode.Selected reaction monitoring(SRM)using the precursor to product ion combinations of m/z 310.0→264.9 and m/z 285.1→154.0 was performed to detect methadone and diazepam(the internal standard),respectively.RESULTS:The calibration curves for methadone had good linearity over the range of 2.5～500 ?g?L-1(r=0.999 0).The limits of quantitation for methadone was 2.5 ?g?L-1.The average recoveries for methadone(at high,medium and low concentrations)were 100.23%,101.20% and 101.39%,respectively.The within-day RSD(n=5)and between-day RSD(n=3)were all less than 10%.CONCLUSION:The method is simple,rapid,sensitive,accurate,and reproducible and it provides an analytical procedure for clinical monitoring of plasma concentration of methadone and its pharmacokinetic studies.