Transport of artemisinin and sodium artesunate in Caco-2 intestinal epithelial cells

J Pharm Sci. 1996 Jun;85(6):577-9. doi: 10.1021/js960001i.

Abstract

Artemisinin and its derivatives are becoming interesting alternatives to the commonly used antimalarial drugs because they are efficient in treating severe and multidrug resistant forms of Plasmodium falciparum malaria. A major drawback is the occurrence of recrudescence some time after treatment. Moderate oral bioavailability has been suggested as a possible cause. As one of the factors that might limit absorption after oral administration, we studied the intestinal permeability using an in vitro system of the intestinal mucosa, Caco-2. Concentrations of artemisinin were determined by UV after alkaline degradation, while for sodium artesunate, a capillary electrophoresis method was developed. Artemisinin easily crossed the epithelial cells by passive diffusion (Papp = 30.4 +/- 1.7 x 10(-6) cm s-1, pH 7.4). Permeability of the hemisuccinate analogue, sodium artesunate, was 8-fold lower (Papp = 4.0 +/- 0.4 x 10(-6) cm s-1 at pH 7.4) and strongly dependent on pH, which might result in site dependent resorption in an in vivo situation. Enzyme catalyzed ester hydrolysis of sodium artesunate in Caco-2 monolayers to the biologically active metabolite, dihydroartemisinin, was moderate. The results indicate that the transepithelial permeability is probably not a limiting factor in the overall absorption process after oral administration of artemisinin or sodium artesunate. Solubility, dissolution rate, stability, and first-pass metabolism are suggested as alternative limiting factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antimalarials / pharmacokinetics*
  • Artemisinins*
  • Artesunate
  • Biological Transport
  • Caco-2 Cells
  • Cell Membrane Permeability
  • Chemical Phenomena
  • Chemistry, Physical
  • Humans
  • Hydrogen-Ion Concentration
  • Intestinal Absorption*
  • Intestinal Mucosa / metabolism*
  • Kinetics
  • Sesquiterpenes / pharmacokinetics*
  • Solubility

Substances

  • Antimalarials
  • Artemisinins
  • Sesquiterpenes
  • Artesunate
  • artemisinine