Comparative pharmacokinetics of prim-O-glucosylcimifugin and cimifugin by liquid chromatography-mass spectrometry after oral administration of Radix Saposhnikoviae extract, cimifugin monomer solution and prim-O-glucosylcimifugin monomer solution to rats

A sensitive and reliable liquid chromatographymass spectrometry method has been developed and validated for simultaneous determination of cimifugin and prim-O-glucosylcimifugin in rat plasma after oral administration of Radix Saposhnikoviae (RS) extract, prim-O-glucosylcimifugin monomer solution and cimifugin monomer solution. Plasma samples were pretreated by protein precipitation with acetonitrile containing the internal standards puerarin and daidzein. LC separation was achieved on a Zorbax SB-C18 column (150x?4.6?mm i.d., 5?mu m) with 0.1% formic acid in water and methanol by isocratic elution. The detection was carried out in select-ion-monitoring mode with a positive electrospray ionization interface. The fully validated method was successfully applied to the pharmacokinetic study of the analytes in rats. A bimodal phenomenon appeared in the concentrationtime curve of prim-O-glucosylcimifugin and cimifugin after oral administration of RS extract. Prim-O-glucosylcimifugin mainly transformed to cimifugin when it was absorbed into blood. Both absorption and elimination of cimifugin after oral administration of RS were longer than after administration of single cimifugin. The pharmacokinetic parameters (AUC0t, AUC0 infinity and t1/2) of prim-O-glucosylcimifugin and cimifugin by giving cimifugin monomer solution, prim-O-glucosylcimifugin monomer solution and RS extract had significant differences (P?<?0.05). Copyright (c) 2012 John Wiley & Sons, Ltd.