Customized Hydrogel for Sustained Release of Highly Water-Soluble Drugs.

Highly water-soluble drugs, due to the rapid diffusion in water, are difficult to be released sustainably. To address the issue, a hydrogel with a core-shell structure is designed for the release of highly water-soluble drugs. The core is used to load the drug and the shell is devoted to isolating the drug from the release medium, which can decrease the drug concentration gradient and the driving force of drug release. The core-shell structure prolongs the drug release time by extending the drug release pathway. Moreover, the core-shell hydrogel possesses high swelling properties to reside in the stomach. The results demonstrate that the customized hydrogel can prolong the release of the highly water-soluble drug (metformin hydrochloride) for more than 50 h and alleviate the burst release of the drug.

Onion-structure bionic hydrogel capsules based on chitosan for regulating doxorubicin release.

Inspired by the multilayer structure of onion, herein, a novel strategy to prepare bionic multilayer hydrogel capsules for inhibiting burst release of doxorubicin (DOX) is reported. The bionic multilayer hydrogel capsules are prepared by the ionotropic crosslinking method. Compared with monolayer hydrogel capsules, the multilayer hydrogel capsules can largely homogenize the distribution of DOX and suppress the concentration gradient of DOX between the outermost hydrogel layer and external environment and the dense cuticular membranes of capsules can restrict the migration and diffusion of DOX. As a result, a significant inhibition of the burst release of DOX can be achieved. Moreover, the bionic multilayer hydrogel capsules demonstrate pH sensitivity and good biocompatibility to human epidermal keratinocyte (HaCaT) cells. This work opens up a new horizon in the burst release of biomaterial-based hydrogels for drug delivery system.