Objective: To study the pharmacokinetics and bioequivalence of self-prepared rhubarb acid enteric-coated sustained-release pellets

and compare the pharmacokinetics of rhein between rhubarb acid enteric-coated sustained-release pellets and solution

make clear the pharmacokinetic character of the sustained release preparation in vivo. Method: Ten rabbits were given a single oral dose of 35 mg·kg-1 of self-prepared rhubarb acid enteric-coated sustained-release pellets (test preparation) and the sodium alginate solution of rhein (reference preparation) in a crossover study. HPLC was applied to determine the plasma concentrations of rhein before and 0.5

1

2

3

4

6

8

9

10

12

24

28

32

36 h after administration of the medicine. The pharmacokinetic parameters were calculatedand statistically analyzed. Result: The plasma concentration curves of both the sustained-release matrix pellets and the sodium alginate solution of rhein had one peak. The main pharmacokinetic parameters of test preparation were as follows: tmax(9.73±0.68)h

Cmax(3.00±0.81) g·L-1

AUC0～∞(59.21±4.35) mg·L -1·h-1

MRT(21.12±1.12)h; and those of reference preparation were as follows: tmax(4.17±0.12)h

cmax(2.71±0.74) g·L-1

AUC0～∞(39.72±3.11) mg·L-1·h-1

MRT(9.33±2.08)h respectively. Conclusion: Compared with the sodium alginate solution of rhein

the self-prepared rhubarb acid enteric-coated sustained-release pellets have better bioavailability.