Derived from starch, cyclodextrins sport a hydrophilic exterior and a hydrophobic cavity. Cyclodextrins were once considered as possible catalysts for chemical reactions, but that application never materialized. Today, their amphiphilic properties and large size make them excellent emulsifiers in the food industry. Pharmaceutical companies are also interested in cyclodextrins, particularly for solubilizing oily compounds. Ten beta-cyclodextrins are used today in the United States, Europe, and Japan in oral drug formulations.
Parenteral use is limited due to hemolytic and renal toxicity observed after systemic exposure.
Cydex is working to improve both solubility and systemic tolerance of cyclodextrins. Captisol is a donut-shaped cyclodextrin that sequesters poorly soluble drugs in its inner cavity while dissolving in water due to its hydrophilic exterior. Once in the bloodstream, the captisol-drug complex dissociates, releasing drug molecules that might normally have been digested in the gut. Cydex is collaborating with several pharmaceutical companies on the use of cyclodextrins to improve drug solubility. The privately held company was founded in 1993 by scientists from the University of Kansas Biosciences Center.