Objective: By establishing UPLC method for determining binding rate between salvianolic acid B

danshensu and rat

bovine serum albumin(BSA)

human plasma proteins

to analysis difference of plasma protein binding rate of these two components. Method: UPLC method was employed to determine contents of salvianolic acid B and danshensu with mobile phase of acetonitrile(A)-1% formic acid solution(B) for gradient elution(0-2 min

18% A;2-3 min

18% -30% A;3-6 min

30% A) and detection wavelength at 280 nm.Equilibrium dialysis method was used to investigate binding rates of salvianolic acid B and danshensu with different plasma proteins. Result: Linear ranges of salvianolic acid B and danshensu in 3 kinds of plasma were 2-200 mg·L-1

and in dialysis filtrates were 0.5-20 mg·L-1.Mean protein binding rates of salvianolic acid B in rat

human plasma and BSA were 90.60%

92.25%

87.55%

respectively;these of danshensu were 35.44%

37.71%

33.49%

respectively. Conclusion: Binding rates of different concentrations of salvianolic acid B and danshensu in the same plasma have no significant difference

but binding rates of salvianolic acid B with 3 kinds of plasma protein are higher than danshensu.