Abstract: AIM :To establish a Reversed-Phase high performance liquid chromatography method for determina- tion of plasma ropivacaine in dog .METHODS:The sam- ple was deproteinated by acetonitrile and determined with RP-HPLC and ultraviolet detection .the analytical column was Intertsil C18 column (4 .6 mm×250 mm, 5 ^μm).The mobile phase consisted of methanol :H2O(50 ∶50), the detection wavelength was 215 nm and the flow rate was 1 .4 ml·min ^-1 , the column temperature was 20 ℃, the sensitivity was 0 .02AUFS respectively .The volume of sample for detection is 10 ^μl .RESULTS:The linear range was 0 .1 -25 ^μg·ml^-1(r =0 .9992).The recovery of ropivacaine was 91 .2 %-93 .6 %, RSD was 2 .10 %- 3 .40 %(n =6).The detection limit was 0 .05 ^μg·ml ^-1 . the intra-day and interday precisions of assay for ropiva- caine was 1 .35 %-2 .88 % and 1 .80 %-3 .76 %.The quantative analysis of ropivacaine in plasma was not inter- fered by impurities .CONCLUSION:The assay method was shown to be suitable for determination the concentra- tion of ropivacaine in plasma.The method is simple , ac- curate , sensitive and reproducible .

Key words: RP-HPLC, plasma concentration , ropiv- acaine , local anesthetics , plasma