Changes in the solubility of beta-cyclodextrin on complex formation: Guestenforced solubility of beta-cyclodextrin inclusion complexes

The most common native host molecule, beta-cyclodextrin (cycloheptaamylose) is able to form inclusion complexes with a large variety of guest molecule s (or ions) of different size and shape. The properties of the included gue st molecule are highly influenced by the host-guest interaction, and the pr actical usefulness of beta-cyclodextrin is dependent on these effects. Thes e changes are mainly investigated from the point of view of the guest and t o a lesser extent from that of the host. In spite of this, the kind of gues ts and that of the host-guest interactions during the formation of the incl usion complex seem to influence the properties of the hydrophilic domain of beta-cyclodextrin (i.e. that of the supramolecule itself), too, and this e ffect can be well demonstrated by the change of solubility of different bet a-cyclodextrin inclusion complexes. This change can be best correlated with the solubility of the guest as if the guest enforced its solubility on the supramolecule.