Cyclodextrins: Their future in drug formulation and delivery

Since their discovery, cyclodextrins and their ability to form inclusion complexes have fascinated chemists, formulators and recently, entrepreneurs. This mini-review has as its objective, a critical assessment of the current status of cyclodextrins in the formulation and delivery of pharmaceuticals and commentary on their potential future uses. The emphasis will be on answers to common questions often asked of pharmaceutical scientists working in this area. Why use cyclodextrins for drug solubilization and stabilization when alternative techniques are available? Why the greater interest in modified cyclodextrins and not the parent cyclodextrins? If a drug forms a strong cyclodextrin inclusion complex, how is the drug released in vivo? Does the injection of a cyclodextrin/drug complex alter the pharmacokinetics of the drug? Are there drug products on the market which contain cyclodextrins? What is the regulatory status of cyclodextrins? Although definitive answers to all these questions are not possible at this time, many of these questions are answerable, and educated and informed responses are possible for the rest.