Abstract: AIM: To examine the characters of distribution of two epimers of glycyrrhizic acid (GL) including α-GL and β-GL in mice. METHODS: After iv administration of a single 53.0 mg·kg^-1 α-GL or β-GL in mice at 5, 15, 30, 60, and 180min, the concentrations of α-GL or β-GL in some tissues were determined by HPLCUV method, and the features of distribution of α-GL and β-GL were evaluated and compared. RESULTS: α-GL and β-GL were all quickly distributed.Except the plasma, the concentrations of α-GL and β-GL were higher in the liver than that in other tissues.The second peak of enterohepatic circulation could be observed at 30 min after iv administration.The concentration of α-GL in the liver was significantly higher than that of β-GL, but it was lower than or similar to that of β-GL in the plasma and other tissues after iv.Then the levels declined rapidly in all tissues but the intestine at 180min after iv administration, meanwhile, β-GL maintained rather high concentrations in various tissues, which were all 30 %-70 % of the peaks. CONCLUSION: After iv administration, α-GL is target to the liver, and can be efficiently converted to more α-GA than β-GL, and it nearly has no accumulation in the tissues.The tissue distribution of β-GL inmice appears to be wild throughout the body, and the metabolism is slower than that of α-GL to accumulate in some tissues.

Key words: α-GL, β-GL, tissue distribution, HPLC-UV