When can cyclodextrins be considered for solubilization purposes?

This communication is intended to address the question: How can one determine, with minimum experimentation, if cyclodextrins (CDs) might be the right choice as solubilization enhancers for a given poorly water-soluble drug? The cyclodextrin utility number, U(CD), a dimensionless number, is introduced to assess the feasibility of the use of CDs in dosage forms. U(CD) is a lumped-parameter consisting of the dose of the drug, the workable amount of CD, the binding constant, and the drug solubility in the absence of CDs. U(CD) was been extended to ionizable drugs that show synergistic increase in solubility due to ionization and complexation. U(CD) is a guiding and not a predictive tool that the formulator can use. Copyright 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:927-932, 2003