Abstract
Cyclodextrins (CDs) consist of D- glucopyranoside units that are linked together by glycosidic bonds to form cyclic oligosaccharides. They are mainly employed to ameliorate the physicochemical properties and biologi cal properties of poorly aqueous soluble drugs by the formation of inclusion complexes between the CD and drug. Inclusion complex formation requires the host molecules to fit completely or partially within the CD cavity. The uncomplicated settlement of guest molecules within the CD cavity, therapeutic dose, toxicity and stoichiometry all change according to the physicochemical properties of the guest and host molecules. However, dosage formed volume depends on the amount of CD required. So high amount of CD used leads to high dosage formed volume. Thus, it is necessary to improve the solubilization efficiency in order to use lesser amounts of CD. This could be reached by adding small amounts of water-soluble substances such as polymers, organic acids, amino acids, co-solvents, etc. to the inclusion complex. This review mainly focused on the aspects related to the formation of drugs and CDs' inclusion complex by using different types of water-soluble substances to optimize the amount of CD used in the complexation in order to improve drug solubility, and decrease the bulk of dosage form.