β-Cyclodextrin-conjugated amino poly(glycerol methacrylate)s for efficient insulin delivery

A series of cationic polymers based on β-cyclodextrin (β-CD)-conjugated amino poly(glycerol methacrylate)s (PGOHMAs) was synthesized for potential insulin delivery by forming polyelectrolyte complexes (PECs). Both linear and star-shaped poly(glycidyl methacrylate)s were functionalized with mono(6-(diethylenetriamine)-6-deoxy)-β-CD and diethylenetriamine to obtain CD-DETA-PGOHMAs and DETA-PGOHMAs, respectively. The resulting polymers were characterized by 1H NMR, FT-IR, elemental analysis, and TGA, and then used to prepare PECs with insulin. The association efficiency and loading capacity of CD-DETA-PGOHMAs were higher than those of DETA-PGOHMAs. The release of insulin depended on the introduction of β-CDs, the backbone architecture of the polymers, as well as the pH. The competitive binding release study indicted that insulin could be released rapidly when 1-aminoadamantane hydrochloride (ADA) was used as a competitive binding guest molecule. The in vitro cytotoxicity study revealed that CD-series polymers have much lower toxicity than the D-series. The CD-DETA-PGOHMA/insulin complexes, with lower cytotoxicity and proper release rate, showed great potential for insulin controlled release.