Enhanced microdialysis extraction efficiency of ibuprofen in vitro by facilitated transport with β-cyclodextrin

A novel approach to increase microdialysis recovery (extraction efficiency, E-d) by facilitated transport through the microdialysis membrane is described. This new approach facilitates mass transport into the microdialysis probe by inclusion of a complexation agent in the microdialysis perfusion fluid. In these studies, beta-cyclodextrin (beta-CD) (0.25-2.0 w/v%) was included in the microdialysis perfusion fluid consisting of a Ringer's solution (155 mM NaCl, 4.0 mM KCI, 2.4 mM CaCl2), beta-CD forms known inclusion complexes with 2-(4-isobutylphenyl)propionic acid (ibuprofen), Ibuprofen E-d was significantly enhanced (1.5-2.0 times) through different microdialysis membrane materials. The effect of microdialysis membrane material (polycarbonate/polyether, AN-69, cuprophan), pH, beta-CD concentration, and ibuprofen concentration on the E-d was examined. Only the polycarbonate/polyether membrane was able to give an E-d greater than 100%, In general, a maximum increase in E-d was found when 0.5 w/v% beta-CD was included in the perfusion fluid, Variations in the ibuprofen concentration external to the microdialysis probe did not significantly change E-d when 0.5 w/v% beta-CD was included in the perfusion fluid, In contrast to the ibuprofen data, beta-CD inclusion in the microdialysis perfusion fluid did not affect antipyrine E-d. Antipyrine does not form known inclusion complexes with beta-CD. The ability of beta-CD to increase microdialysis E-d is explained by facilitated transport.