Improved oral bioavailability of artemisinin through inclusion complexation with β- and γ-cyclodextrins

The bioavailability of beta- and gamma -cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250 (R). Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using the parameters, total area under the plasma level-time curve (AUC(0-proportional to)), peak plasma concentration (C-max), and time to reach peak plasma concentration (T-max). A statistically significant difference was observed between the values of the complexes and Artemisinin 250 (R) for the three parameters. However, no statistically significant difference was observed between the values of the beta- and gamma -cyclodextrin complexes. Moreover, the 90% confidence interval for the ratio of the AUC(0-proportional to) values of the beta -cyclodextrin complex over those of Artemisinin 250 (R) was estimated to be between 1.51-2.04, while that of C-max was between 1.73-2.93. For the gamma -cyclodextrin complex, the respective intervals were 1.30-1.76 and 1.43-2.43. These findings indicated that the beta- and gamma -cyclodextrin complexes had a much higher rate and extent of bioavailability compared to Artemisinin 250 (R). In addition, the absorption of artemisinin was observed to be poor and negligible when the preparations started to arrive in the colon. This could be attributed to poor dissolution of artemisinin in the semi-solid faecal matter in the lower part of the gastrointestinal tract. (C) 2001 Elsevier Science BN. All rights reserved.