Drug/cyclodextrin/hydroxy acid multicomponent systems. Properties and pharmaceutical applications

The objective of this mini-review is to summarize the findings concerning the properties and the pharmaceutical applications of multicomponent complexes made of a sparingly water-soluble amino-type drug, a cyclodextrin, and a hydroxy carboxylic acid. Simultaneous complexation and salt formation with these acids significantly increase the solubilizing power, allowing us to reduce the amount of cyclodextrin necessary for making the targeted formulation. In many cases, the aqueous solubility of the hydrophobic drug can be enhanced by several orders of magnitude, while that of CD can be enhanced more than 10-fold. The mechanism through which these complexes elicit their synergetic effects on the drug solubility is also discussed. Finally, some general observations are made concerning the structural requirements of the drug necessary for exploiting the aforementioned effect.