Effect of Radix euphorbiae pekinensis extract on bioavailability of paclitaxel after their oral co-administration

Objective To evaluate the effect of Radix euphorbiae pekinensis extract on the permeability and bioavailability of paclitaxel co- administered orally. Methods Based on Ussing Chamber and in vivo experiment, the permeability and bioavailability of paclitaxel were evaluated after oral co-administration with radix euphorbiae pekinensis in rats. The contents of paclitaxel in the permeates and the blood samples were determined using HPLC and LC- MS/MS method, respectively.Results In Radix euphorbiae pekinensis co-administration group, the Papp of the mucosal-to-serosal(M-S) transport or serosalto- mucosal transport(S- M) of paclitaxel in the jejunum or ileum segment differed significantly from those in verapamil coadministration group and blank control group(P0.05), but the Papp of S- M transport in the colon showed no significant difference from that in the blank control group. In the blank group, the average absolute bioavailability(AB%) of orally administered paclitaxel was only 2.81%, compared to that of 7.63% in radix euphorbiae pekinensis group. The average AB% in verapamil group was about 1.5 times that of the blank group. Conclusion Co-administration of Radix euphorbiae pekinensis extract can increase the bioavailability of orally administered paclitaxel.