A copolymer capsule with a magnetic core for hydrophilic or hydrophobic drug delivery via thermo-responsive stimuli or carrier biodegradation

In this work, we report the successful preparation of a dual-responsive polymer microcapsule carrier with a magnetic core, Fe3O4@capsule nanoparticles, by cross-linked polymerization of N-isopropylacrylamide and acrylamide in the presence of N,N'-bis(acryloyl) cystamine as a crosslinker. These novel drug carriers can undergo volume phase transition upon changing the environmental temperature or biodegradation of the polymer capsule by cleavage of the predesigned disulfide bonds within the crosslinker in the presence of glutathione (GSH) for hydrophilic or hydrophobic drug release. Herein, we take doxorubicin hydrochloride (DOX) as a hydrophilic drug model and curcumin as a hydrophobic drug model for investigating thermal responsiveness and biodegradation of magnetic polymer capsule carriers. Results indicate that DOX is released rapidly with thermal treatment and the release rate of DOX at PBS 5 is much faster than that at PBS 7.4. In addition, the release of water-insoluble drug curcumin is much faster with the assistance of GSH than without.