“…Cyclodextrin (CD) is a cyclic oligosaccharide obtained from starch by enzymatic hydrolysis, mainly containing 6, 7 and 8 glucopyranose units forming α-CD, β-CD, and γ-CD respectively. α-, β- and γ-CD have hydrophobic cavities with internal diameters of approximately 0.47–0.53, 0.60–0.65 and 0.75–0.83 nm, respectively. − Hydroxyl groups within the cyclodextrins are not only responsible for aqueous solubility but also allow the hydroxyl groups to interact with the hydrophilic components, making the hydrophobic drugs water-soluble complexes. − In this inclusion complexation phenomenon, multiple cyclodextrin fragments can be involved by encapsulating one or more guest molecules, which can form a variety of complexation phenomena such as 1:1, 1:2, 2:2, etc. Therefore, this section is divided into three main sections on cyclodextrin-inclusive drugs, focusing on (1) natural cyclodextrin-inclusive drugs, (2) modified cyclodextrin-inclusive drugs and (3) cyclodextrin polymer-inclusive drugs.…”