Determination of Guaifenesin in Human Plasma by LC/MS/MS and Its Pharmacokinetic Study

OBJECTIVE:To determine the content of guaifenesin in human plasma samples by LC/MS/MS and to study its pharmacokinetics.METHODS:After being extracted by ethyl acetate,the alkalized plasma samples were separated on aquasil C18 column with methanol-1% methanoic acid(70:30)as mobile phase and paracetamol as internal standard.The detection was performed on a HPLC-triple quadrupole tandem mass spectrometer by selected reaction monitoring(SRM) mode via elect-rospray ionization(ESI).In quantitative analysis,the ionic reaction of guaifenesin was m/z199→m/z125 and that of paracetamol was m/z152→m/z110.RESULTS:The method was linear in the concentration range of 5.0～2 500.0ng·mL-1(r=0.995 3)for guaifenesin,with lower limit of quantification at 5.0 ng·mL-1.The main pharmacokinetic parameters in 20 healthy volunteers after administration of single oral dose of 0.2 mg guaifenesin tablets were the following:Cmax:(754.6±190.5)ng·mL-1;t1/2:(0.97±0.12)h;tmax:(0.63±0.22)h;AUC0～t:(1 435.8±441.9)ng·h·mL-1;AUC0～∞:(1 4 44.9±449.3)ng·h·mL-1.CONCLUSION:The established method is simple,rapid and sensitive,and suitable for clinical pharmacokinetic study of guaifenesin.