Cyclodextrins are crystalline, water soluble, cyclic, non-reducing, oligosaccharides built up from six, seven, or eight glucopyranose units. Three naturally occurring CDs are alpha Cyclodextrin, beta Cyclodextrin, and gamma Cyclodextrin. All the hydroxyl groups in Cyclodextrins are oriented to the outside of the ring while the glucosidic oxygen and two rings of the non-exchangeable hydrogen atoms are directed towards the interior of the cavity. This combination gives Cyclodextrins a hydrophobic inner cavity and a hydrophilic exterior. The hydrophobic internal cavity provides the capability to form inclusion complexes with a variety of "guest" hydrophobic molecules (e.g. aromatics, alcohols, halides, fatty acids, esters, etc.). |