Determination of lansoprazole in healthy human plasma by LC-MS/MS:application to pharmacokinetics study

OBJECTIVE To study the pharmacokinetics of lansoprazole injection with a single and multiple dose intravenous(iv)drop administration in chinese healthy volunteers.METHODS 30 volunteers were divided into three groups at random,with 5 males and 5 females in each group.The volunteers in each group were administrated with single dose of lansoprazole 15,30,60 mg,respectively.In multiple dose study,those who got dose of 30 mg were administrated twice a day for 5 days.Lansoprazole concentration in plasma was determined by LC-MS/MS.RESULTS The main pharmacokinetic parameters obtained from single-dose study of 15,30,60 mg,respectively,were as follows:tmax(0.51±0.03)、(0.52±0.04)、(0.54±0.08)h;Cmax(959.3±190.9)、(2 141.2±563.7)、(4 068.8±752.5)μg·L-1 ;AUC(0-t)(2 354.7±1 753.1)、(4 774.8±2 984.3)、(1 1057.3±5 360.5)μg·h·L-1;AUC(0-∞)(2 548.8±2 040.2)、(4 967.0±3 348.7)、(11 469.0±5 881.5)μg·h·L-1;t1/2(2.0±1.3)、(1.6±0.9)、(1.8±0.9)h;The main pharmacokinetic parameters of steady-state were as follows:tmax 0.5 h,Cmax(1 984.7±389.7)μg·L-1;AUCSS(4 853.6±3 365.5)μg·h·L-1;t1/2(1.7±1.1)h;Cav(541.833±315.743)μg·L-1.CONCLUSION AUC(0-t),AUC(0-∞),Cmax and V exhibited dose-dependent linear pharmacokinetic characteristics over the dose of 15-60 mg.It has been shown that no accumulation occur in vivo.Plasma concentrations of lansoprazole have reached steady state till 5 days.