Pharmacokinetics and pharmacodynamics of lansoprazole in the healthy volunteers

OBJECTIVE To study pharmacokinetics and pharmacodynamics of lansoprazole in the healthy volunteers.METHODS Twenty healthy volunteers were randomly divided into two group(lansoprazole 30 mg and omeprazole 40 mg),with 5 males and 5 females in each group.The pH of gastric juice in healthy volunteers was monitored within 24 hours,the plasma drug concentration of lansoprazole and omeprazole was detected by HPLC.DAS2.0 and SPSS11.5 was performed for calculating pharmacokinetics parameter and comparing the data of pH.RESULTS The main pharmacokinetic parameters of lansoprazole was as follows:AUC0-t(7.2±3.9)mg·h·L-1,AUC0-∞(7.7±4.6)mg·h·L-1,AUMC0-t(24.0±21.2),AUMC0-∞(33.2±35.6),MRT0-t(2.8±1.1)h,MRT0-∞(3.4±1.8)h,t1/2(2.2±1.3)h,CL(5.3±3.1)L·h-1,Cmax(2.3±0.4)mg·L-1;The main pharmacokinetic parameters of omeprazole was as follows: AUC0-t(4.6±4.1) g·h·L-1,AUC0-∞(4.6±4.2) g·h·L-1,AUMC0-t(11.1±15.1),AUMC0-∞(12.2±17.1),MRT0-t(1.8±0.8)h,MRT0-∞(1.9±0.9)h,t1/2(1.1±0.6)h,CL(13.6±7.4)L·h-1,Cmax(2.1±0.8)mg·L-1.The pH value of gastric juice was rising significantly after single intravenous lansoprazole or omeprazole application,and maintained the pH at(5.1±1.6)and(3.9±1.9)twelve hours later.CONCLUSION The plasma drug concentration was different from the tissue drug concentration,and uncorrelated with the pH.The effect of lansoprazole was cumulative over extended periods.