PHARMACEUTICAL APPLICATIONS OF CYCLODEXTRINS .1. DRUG SOLUBILIZATION AND STABILIZATION

Cyclodextrins are cyclic oligosaccharides which have recently been rec ognized as useful pharmaceutical excipients. The molecular structure o f these glucose derivatives, which approximates a truncated cone or to rus, generates a hydrophilic exterior surface and a nonpolar cavity in terior. As such, cyclodextrins can interact with appropriately sized m olecules to result in the formation of inclusion complexes. These nonc ovalent complexes offer a variety of physicochemical advantages over t he unmanipulated drugs including the possibility for increased water s olubility and solution stability. Further, chemical modification to th e parent cyclodextrin can result in an increase in the extent of drug complexation and interaction. In this short review, the effects of sub stitution on various cyclodextrin properties and the forces involved i n the drug-cyclodextrin complex formation are discussed, Some general observations are made predicting drug solubilization by cyclodextrins. In addition, methods which are useful in the optimization of complexa tion efficacy are reviewed. Finally, the stabilizing/destabilizing eff ects of cyclodextrins on chemically labile drugs are evaluated.