Pharmacokinetic parameters of 2 epimers of glycyrrhizic acid in rats determined by HPLC

OBJECTIVE To optimize the HPLC-UV conditions for measuring plasma concentration of 2 epimers of glycyrrhizic acid and to determine the pharmacokinetic parameters of 2 epimers of glycyrrhizic acid(GL)in rats.METHODS α-GL and β-GL solvents were intravenously injected into rats at a dose of 50 mg·kg-1.The concentration in the plasma was measured by HPLC-UV.Experimental data and pharmacokinetic parameters processed with the computer program SPSS were compared betweenα-GL andβ-GL.RESULTS The main pharmacokinetic parameters inα-GL group were:λz=0.0064±0.01 min-1,t1/2=(100.95±0.35)min,tmax=(30±0.10)min,Cmax=(79.50±0.10)μg·ml-1,AUC0-360=(1 442.98±8.04)μg·min·ml-1, AUC0-∝ =(1 475.35±3.87)μg·min·ml-1;and those inβ-GL group were:λz=(0.008 3±0.01)min-1,t1/2=(85.85±0.42) min,tmax=(45±0.2)min,Cmax=(94.64±0.31)μg·ml-1,AUC0-360=(2 716.51±7.51)μg·min·ml-1,AUC0-∝=(3 603.00± 8.82)μg·min·ml-1.CONCLUSION The method can be used to determine plasma concentration of 2 epimers of glycyrrhizic acid in rats and is suitable for study on pharmacokinetics.There are significant differences between the main pharmacokinetic parameters of 2 epimers of glycyrrhizic acid(GL)in rats..