CHAPTER 7: Cucurbiturils in Drug Delivery And For Biomedical Applications

This chapter illustrates the potential of cucurbiturils, a synthetic class of macrocycles, as well as their derivatives and analogues for drug delivery applications, attempting a comprehensive coverage of the rapidly unfolding scholarly activity in this area up to including early 2013. Cucurbiturils are water soluble, pumpkin-shaped, symmetrical, and rigid host molecules, that encapsulate various types of drug molecules, neutral as well as positively charged, via non-covalent interactions which lead up to femtomolar affinities. Due to their peculiar chemical structure, a secluded hydrophobic inner cavity with two partially negative charged carbonyl portals, they provide an inert environment to protect several drug molecules from unwanted bimolecular chemical and photochemical reactions, and the complexation alters the chemical reactivities of encapsulated drugs. Examples of the effects of cucurbiturils on the solubilization, ionization, activation, stabilization, and chemical protection (in vitro as well as in vivo) of drug molecules are provided. In addition, applications of cucurbiturils and their derivatives in targeted drug delivery, for controlled drug release, and for sensing biologically important molecules are discussed. The spurred interest in cucurbituril-based drug delivery systems and their low, if not negligible, acute toxicity are expected to lead to drug delivery approaches, which are complementary to those for other supramolecular host molecules, particularly cyclodextrins, and to alternative formulation systems such as polymers, hydrogels, and liposomes.