Physicochemical properties and complex formation abilities of large-ring cyclodextrins

Large-ring cyclodextrins (LR-CD) are cyclic alpha-1,4-glucans composed of nine to more than several hundred glucopyranose units. The first definitive evidence for the existence of LR-CD with a degree of polymerization between 9 and 13 was reported in 1965. That LR-CD study did not reveal anything that attracted attention. LR-CD with a degree of polymerization between 9 and 31 were isolated and characterized during the past decade, and so began to attract considerable attention. This mini-review summarizes the findings of LR-CD with regard to the potential for host-guest interactions and corresponding applications.