Importance of cyclodextrins into inclusion complexes

Cyclodextrins are natural cyclic oligosaccharides formed by glucose unites that were discovered in 1891, and the structures were confirmed in the mid-1930s. Their industrial significance became obvious in the 1970s. The most common natural cyclodextrin consist of six ( ?- cyclodextrin), seven (?- cyclodextrin ), and eight (?- cyclodextrin) glucopyranose units, the macrocyclic cyclodextrins consist of a hydrophilic outer surface and a lipophilic central cavity. The mainly uses of cyclodextrins are complexing agents to increase aqueous solubility of poorly soluble drugs, as well as, increase their bioavailability and stability. The other application of CDs is to crosslink for forming polymers which used in drug delivery. CDs can be used to prepare pseudorotaxanes and rotaxanes via inclusion complexes. The first rotaxane incorporating CDs was prepared 1981. This review will discusses the structures, preparation and properties of CDs. Industrial and pharmaceutical application of CDs will also be included in this review. Hydrophilic- hydrophobic interaction routes to pseudorotaxanes and rotaxanes will be explained.