Investigation of Nonionic Surfactant-Cyclodextrin Hydrogels for Hydrophobic Drug Delivery

Sammanfattning

Supramolecular hydrogels have attracted increasing attention in drug delivery, tissue engineering, and injectable biomaterials because of their high water content, good biocompatibility, and dynamic network structures. Cyclodextrin-based supramolecular systems can form network structures through host–guest interactions. These systems usually require mild cross-linking conditions and allow flexible control of material properties, which gives them potential for biomedical applications. However, studies on the gelation behavior of different nonionic surfactant–cyclodextrin systems and their structure–property relationships are still limited. In this study, six nonionic surfactants were selected, including the polysorbates 20 and polysorbate 80, and the alkyl glycosides α-dodecyl maltoside, β-dodecyl maltoside, decyl glucoside, and lauryl glucoside. These surfactants were mixed with α-cyclodextrin and β-cyclodextrin to investigate their gelation behavior and possible assembly mechanisms. The study first screened the phase behavior of the systems by changing the surfactant type, cyclodextrin type, water content, and molar ratio. The study further carried out rheological measurements, nuclear magnetic resonance analysis, injectability evaluation, and in vitro curcumin release experiments. The results showed that different surfactants formed different assembly structures with cyclodextrins. Most alkyl glycoside systems showed phase separation or precipitation after centrifugation and failed to form stable hydrogels. The nuclear magnetic resonance results indicated that the strong host–guest interactions between α-cyclodextrin and dodecyl maltoside favored the formation of dense aggregates rather than continuous three-dimensional networks. In contrast, the systems formed by Polysorbate 20 or Polysorbate 80 with α-cyclodextrin showed better stability. The systems formed stable hydrogels at higher α-cyclodextrin/Polysorbate 80 molar ratios and lower water contents. Rheological measurements showed that these hydrogels had clear viscoelastic behavior. The storage modulus remained higher than the loss modulus. The systems also showed obvious shear-thinning and thixotropic recovery behavior. These results indicated that the hydrogels possessed dynamic and reversible network structures together with good injectability. The study also prepared curcumin-loaded systems using Polysorbate 80/α-cyclodextrin hydrogels as carriers. The results showed that the hydrogels could encapsulate curcumin–cyclodextrin inclusion complexes and provide sustained drug release. Different curcumin-cyclodextrin inclusion ratios influenced the release behavior. These findings suggested that the supramolecular structures and host–guest interactions inside the systems affected the drug diffusion process.