Description: SBE-β-CD, also named as Sulfobutylether beta-cyclodextrin or Captisol, is a highly water-soluble anionic derivative of cyclodextrin that is widely used as an excipient or a formulating agent to increase the solubility of poorly soluble drugs. The sodium sulfonate salt of it is separated from the lipophilic cavity by a butyl ether spacer moiety, namely the sulfobutylether (SBE). SBE-β-CD can form non-covalent inclusion complexes with drug molecules, by so doing, it can improve drug stability, solubility and safety, reduce toxicity, cover up bad smell, and control drug release rate. As an excipient, SBE-β-CD has been used in various formulation including injection, oral, nasal and eye medication. Modification of the structure by charged functional groups can improve the binding affinity of cyclodextrins for oppositely charged guests, therefore it has a specific affinity for drugs containing nitrogen atoms.