Thermoresponsive Drug Release from Polymer Coated Nano Iron Oxide Embedded on Hydroxyapatite

Hyperthermia is a promising cancer therapy due to its minimally-invasive procedure, and the cancer therapeutic efficacy can be improved by magnetic hyperthermia combined with pharamacotherapy. Iron oxide (IO) nanoparticle is a popular medium for hyperthermia treatment, and hydroxyapatite (HA) has been widely used for bone filling and augmentation. IO nanoparticle embedded on hydroxyapatite (HAIO) was synthesized through co-precipitation method, and chitosan or poly (N-isopropylacrylamide) (PNIPAAM) were coated on the HAIO with calcium alginate to form the spheres (Chitosan coated HAIO and PNIPAAM coated HAIO). HAIO, Chitosan coated HAIO and PNIPAAM coated HAIO were used as carriers of 5-fluorouracil (5-FU), one of the drugs for cancer chemical therapy, and the 5-FU release behavior in PBS solution was investigate at ambient and elevated temperatures. The amount of the released 5-FU from the HAIO, Chitosan coated HAIO and PNIPAAM coated HAIO are almost the same at ambient temperature. But at elevated temperature, that from Chitosan coated HAIO was reduced while that from the PNIPAAM coated HAIO was increased.