Comparison of Pharmacokinetics of Baicalein and Baicalin in Rats

OBJECTIVE To compare the pharmacokinetic behavior of baicalein and baicalin in rats.METHODS The concentration of baicalin in rat plasma was determined by a HPLC-ECD method after oral administration of baicalein and baicalin at the equivalent dose.RESULTS After oral administration of baicalein 740 μmol·kg-1,the baicalein was metabolized entirely and the metabolite baicalin was detected mainly in rat plasma.The plasma drug concentration-time curves of baicalin both showed two peaks after oral administration of baicalein and baicalin at the equivalent dose 740 μmol·kg-1 to rats,the ρmax values were 14.63,10.92 mg·L-1 and 8.51,4.87 mg·L-1,and the AUC0~24 h were 149.63 and 63.68 mg·h·L-1,respectively.The relative bioavailability of baicalein was 235.9%.CONCLUSION There were marked differences in the pharmacokinetics between oral administration of baicalein and baicalin at the equivalent dose,and the ρmax values were higher and the bioavailability was better for oral administration of baicalein compared with that of baicalin.