γ-Cyclodextrin hydrogels and semi-interpenetrating networks for sustained delivery of dexamethasone

γ-Cyclodextrin (γCD) networks with tunable texture and complexation efficacy were prepared by direct cross-linking of γCD in aqueous medium containing hydroxypropyl methylcellulose or polyacrylic acid sodium salt (PAcNa) resulting in hydrogels or semi-interpenetrating networks (semi-IPN), respectively. The composition of the networks determined their hardness, compressibility and bioadhesion. γCD networks were loaded by immersion in autoclaved or sonicated dexamethasone suspensions with or without free γCD. Drug loading yield and release profile depended on the capability of the networks to form inclusion complexes. Free γCD in the loading medium decreased dexamethasone uptake (∼50%) through competitive drug complexation and resulted in faster delivery. Such an effect was notable for γCD/PAcNa semi-IPNs due to their smaller mesh size limits the entrance of drug–γCD complexes. Hydrogels and semi-IPNs loaded in the absence of free γCD sustained dexamethasone release for several days. Relationships between the structure of the novel cytocompatible γCD networks and their properties, namely capability to host and to sustain the delivery of hydrophobic drugs, were elucidated.