Objective: To establish a RP-HPLC method to determine plasma concentration of geniposide in rats

and compare pharmacokinetic characteristics of geniposide in Reduning injection and geniposide monomer in rats. Method: Twelve male SD rats were divided into two groups randomly

which were injected Reduning injection and geniposide by tail vein

respectively.Orbital blood at different time points

with syringoside as internal standard

plasma was precipitated proteins with acetonitrile and centrifuged at 13 000 r·min-1 for 10 min.RP-HPLC analysis was performed on an Agela C18 column(4.6 mm×150 mm

5 μm) with acetonitrile-water(14:86) as mobile phase

main pharmacokinetics parameters were calculated with PhoenixTM WinNonlin 6.1 software. Result: Geniposide showed good linearity in 0.100-120 mg·L-1 with r=0.998 7

the lowest limit of quantization of geniposide was 0.100 mg·L-1

the mean extraction recoveries of plasma samples with low

medium and high concentration were (85.9±1.7)%

(96.6±2.3)% and (97.4±1.1)%

respectively.Concentration-time profiles of geniposide were fitted with the two-compartment model both for Reduning injection and geniposide monomer

t1/2 were (0.58±0.11) and (0.55±0.20) h

MRT0-t were (0.41±0.05) and (0.33±0.05) h

respectively

main pharmacokinetic parameters had no significant differences between Reduning injection and geniposide monomer. Conclusion: This developed method was sensitive

rapid and accurate for investigating pharmacokinetics of geniposide in rats.Experimental results showed that the other constituents in Reduning injection have no significant impact on pharmacokinetics of geniposide in rats.