Cyclodextrin-based host–guest supramolecular hydrogels for local drug delivery

Cyclodextrin (CD) is one of the most versatile substances produced by nature and can form supramolecular hydrogels with polymers or small molecules based on non-covalent interactions such as host–guest interaction and hydrogen bonding. CD-based host–guest supramolecular hydrogels have a widespread application in the field of local drug delivery due to their unique properties, such as excellent biocompatibility, shear-thinning nature, and stimuli responsiveness. In this review, we briefly introduce the formation of supramolecular hydrogels with different types of CD (α, β, and γ-CD) and in vitro physicochemical characteristics of these hydrogels. We also describe CD-based host–guest supramolecular hydrogels application in local drug delivery, ranging from intra-tumoral/peritumoral, subcutaneous, intra-articular, bone defect site, intramyocardial and ocular administration to transdermal and intra-renal administration. In addition, this review discusses the challenges and future directions about the clinical translation of CD-based host–guest supramolecular hydrogels.