Prof. Thorsteinn Loftsson (University of Iceland) explains in his lecture on the website of CyclonHit project the mechanism how drugs get through biological membranes, through mucosa, and how these transport processes are influenced by cyclodextrin complexation. It is emphasized that excess cyclodextrin, more than needed to solubilize a given drug, results in decreased penetration through the membranes.
Video-class on the effect of cyclodextrins on drug permeation through membranes
