Abstract:Studies were conducted on the pharmacokinetics of rhein in Apostichopus japonicus. Coelomic fluid, respiratory trees, muscle and integument were sampled after coelomic injecting with a single dose of rhein 5.33mg/kg. The contents of rhein were determined by high performance liquid chromatography. The results showed that the peak time (Tmax), elimination half-time (T1/2b) and the area under the concentration-time curve (AUC) in Coelomic fluid, respiratory trees, muscle and integument were as follows: Tmax 0.26, 0.67, 0.54 and 0.88h ; T1/2b6.24, 26.1, 71.48 and 8.93h; AUC 69.29, 105.6, 132.38 and 20.99mg/L*h. The concentration-time course of rhein in coelomic fluid, respiratory trees and muscle could be described by a two-compartment model, except for the course in integument being described by a one-compartment model. These results are suggesting that rhein can reach the peak time with a high speed absorption in Apostichopus japonicus after injection, while it is slowly metabolized with a long elimination half-time. Rhein is mainly excreted from respiratory trees.
