Cyclodextrin (CD), a cyclic oligosaccharide, has a hydrophobic cavity in its molecule and forms inclusion complexes by incorporating various guest molecules according to the cavity size. The supramolecular inclusion properties of CD are used in various fields such as food, cosmetics, clinical test reagents, fibers, and resins. In recent years, the guest molecules of CD have been expanded to synthetic polymers; for example, CD forms a supramolecular complex with linear polymers such as polyethylene glycol (PEG) in a necklace shape (polypseudorotaxane; PPRX, Fig. 154.1a). Furthermore, when bulky substituents are introduced at the ends of the linear polymers of PPRX, polyrotaxanes (PRX, Fig. 154.1b) are formed, which trap multiple CDs in the molecule. These supramolecular complexes, also known as molecular necklaces, are not only unique in structure but also exhibit various functions through weak interactions between host and guest and are being applied in various fields such as molecular machines, molecular devices, molecular actuators, biomaterials, drug delivery systems, etc. [1]. In particular, the use of CD in the pharmaceutical field, in conjunction with PPRX and PRX technologies, is expanding to various drugs such as protein drugs and nucleic acid drugs as advanced drug delivery carriers.