Objective: To develop an HPLC-FLU method for the determination of capsaicin in rabbit plasma and to study its pharmacokinetics. Method: Six rabbits were given capsaicin nanoemulsions and ethanol solution (1mg ·kg-1) via ear vein by double cycle crossover design

and after 3

6

9

12

15

25

40

60 and 120 min

blood samples were collected. HPLC- FLU was established to determine the plasma concentration of capsaicin and the pharmacokinetic evaluation was carried out. Result: The linear range of capsaicin was 0.197-49.3 mg ·L-1(r=0.999 6) and the limit of detection of capsaicin was 5.9 ng ·mL-1

the average recovery was 102.5%~107.6% with RSD<5%. The t1/2 of capsaicin nanoemulsions and solution was (11.77±2.32) min and (9.53±2.19) min respectively

and the AUC was (5 311±1 324.6) ng ·mL-1 ·kg-1 ·min and (4 909.5±1 110.4) ng ·mL-1 ·kg-1 ·min respectively. Conclusion: This assay method is simple

precise and sensitive enough for the pharmacokinetic study of capsaicin. The pharmacokinectics parameters between capsaicin nanoemulsions and solution had no significant difference ( t test

P>0.05).