Objective: To establish a method for the determination of isorhynchophylline on rat great vessels. Method: The rat great vessels were removed after intragastric administration of Uncariae Ramulus Cum Uncis decoction and liquid nitrogen grinding. The tissue samples which were drawn and treated by adding ethanol and the supernatant were dried by N2.After redissolving in carbinol

the supernatant were detected by HPLC directly. The analysis was carried on an analytical column RP18 WatersTM(4.6 mm×250 mm

5 μm). The mobile phase consisted of carbinol-water (70:30)

triethylamine to adjust pH 8.0 and the flow rate was 0.8 mL· min-1. The UV detection wave length was at 254 nm and the column temperature was kept at 30℃. The retention time of isorhynchophylline was about 12 min. Result: A good linearity was obtained from 0.04 mg· L-1 to 20.0 mg· L-1 for isorhynchophylline. Regression curve was Y=4.644 1X+0.161 2 with a correlation coefficient (R2) of 0.999 2

the average recovery was 99.34%

and the RSD was less than 8.0%. Conclusion: The method is simple

stable and easy for operation. It is shown to be suitable for determination of isorhynchophylline in rat great vessels.