Changes in the Solubility of β-Cyclodextrin on Complex Formation: Guest Enforced Solubility of β-Cyclodextrin Inclusion Complexes

The most common native host molecule, β-cyclodextrin (cycloheptaamylose) is able toform inclusion complexes with a large variety of guestmolecules (or ions) of different size and shape. Theproperties of the included guest molecule are highlyinfluenced by the host-guest interaction, and thepractical usefulness of β-cyclodextrin isdependent on these effects. These changes are mainlyinvestigated from the point of view of the guest andto a lesser extent from that of the host. In spite ofthis, the kind of guests and that of the host-guestinteractions during the formation of the inclusioncomplex seem to influence the properties of thehydrophilic domain of β-cyclodextrin (i.e. thatof the supramolecule itself), too, and this effect canbe well demonstrated by the change of solubility ofdifferent β-cyclodextrin inclusion complexes.This change can be best correlated with the solubilityof the guest as if the guest enforced its solubilityon the supramolecule.