The preparation of pH-sensitive hydrogel based on host-guest and electrostatic interactions and its drug release studies in vitro

A new self-assembly strategy called the synthesis of an amphiphilic crosslinking agent for electrostatic and host-guest is used to prepare a new cellulose-based pH-responsive hydrogel. The amphiphilic crosslinking agent could be encapsulated by poly β-cyclodextrin (β-CDP) through host-guest interaction and be meanwhile attracted by carboxyl groups through electrostatic interaction, then, forming a three-dimensional (3D) gel network structure. Additionally, the linear β-CDP part of the remaining hydrophobic cavity can be equipped with hydrophobic drug molecules to achieve the function of hydrogel expansion. ¹H NMR was used to characterize the synthesized amphiphilic crosslinking agent N,N-dimethyl-1-adamantanamine (DM-AD). FTIR, SEM to characterize the synthesized β-CDP. SEM was used to observe the surface to characterize the prepared hydrogel. The swelling of the gel was measured in aqueous solution, and the swelling kinetic equation was fitted. Meanwhile, the in vitro release of ibuprofen (IBU) in hydrogels was studied. The gel showed a sustained release effect in drug release, and the IBU is hardly released in the gastric juice but is easily released in the intestines. Within 240–1350 min, the release of the drug from the hydrogel conforms to the Korsmeyer and Peppas model, which is a non-Fickian diffusion mechanism. Within 240–1350 min, the drug is released from the hydrogel conforms to the Higuchi model. Furthermore, the gel has the ability of self-healing and self-degradation under acid conditions.