Objective: To clarify the pharmacokinetic characteristics of ziyuglycoside Ⅱ after subcutaneous injection by UPLC-MS/MS. Method: An XTerra® MS C18 reversed phase column(2.1 mm×50 mm

5 μm) was used for the determination of analyte.And mobile phase was consisted of[0.1% formic acid-acetonitrile(9:1)](A) and[acetonitrile-0.1% formic acid(9:1)](B) for gradient elution(0-1.5 min

10% B;1.5-2.0 min

10%-53% B;2.0-3.8 min

53%-62% B;3.8-4.1 min

62%-95% B;4.1-4.5 min

95% B;4.5-4.7 min

95%-10% B;4.7-6.0 min

10% B)

the flow rate was 0.4 mL·min-1

the plasma concentration of ziyuglycoside Ⅱ was performed by negative ion mode in multiple reaction monitoring with electrospray ionization(ESI). Result: The method was successful established for determining the plasma concentration of ziyuglycoside Ⅱ in rats

its linear range was 5-2 000 μg·L-1(R2=0.997).The main pharmacokinetic parameters in rats after subcutaneous injection of ziyuglycoside Ⅱ suspension were obtained as follows:peak concentration(Cmax) of (95.877±11.433) μg·L-1

half-life period(t1/2) of (35.456±23.405) h

area under curve(AUC0-24 h) of (1 221.983±153.379) μg·h·L-1. Conclusion: A rapid

accurate and sensitive method is established for determining plasma concentration of ziyuglycoside Ⅱ in rats

and it can be applied to determine plasma concentration and pharmacokinetic studies of this component.The study provides the pharmacokinetic evidence for the in vivo study and clinical rational medication.