Polysaccharide supramolecular hydrogel microparticles based on carboxymethyl β-cyclodextrin/chitosan complex and EDTA-chitosan for controlled release of protein drugs

New pH-sensitive polysaccharide supramolecular hydrogel microparticles (HMPs) were constructed based on carboxymethyl β-cyclodextrin/chitosan inclusion complex (CM-β-CD/CS) and EDTA-chitosan (EDCS) in aqueous solution. The incorporation of components in HMPs was characterized by ultraviolet, fluorescence and FTIR spectroscopy. The morphology measurements of HMPs were investigated by particle size analyzer and fluorescence microscope. These results showed that CM-β-CD was integrated on the CS by electrostatic interactions, while the hydrogen bonding between CM-β-CD/CS complex and EDCS resulted in the formation of self-assembled HMPs. The swelling and shear rheological behaviors of the HMPs were also investigated, confirming the pH sensitive of the HMPs. In vitro drug release behaviors of the HMPs conducted in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.4) were studied by using bovine serum albumin (BSA) as model protein drug. Results indicated that the BSA-loaded HMPs exhibit highlighted pH-dependent release characteristics and the release of BSA from the HMPs could be described by the Ritger–Peppas model equation, suggesting that the HMPs might be formulated to be a promising candidate for the release of protein drugs.