Repetitive on-demand drug release by magnetic heating of iron oxide containing polymeric implants

Drug release from a polymeric matrix has been externally triggered using an alternating magnetic field in order to develop an on-demand drug delivery implant. Superparamagnetic iron oxide nanoparticles have been distributed in a poly(methyl methacrylate) core, coated with a thermoresponsive layer of poly(butyl methacrylate-stat-methyl methacrylate) containing ibuprofen as a model drug. The release rate of ibuprofen reversibly increased, up to 25-fold, upon exposure to the magnetic field and was found to increase with higher iron oxide loading. Finally, magnetically triggered on-demand drug release was demonstrated under physiologically relevant conditions, namely 37 degrees C in PBS buffer with high ibuprofen content in the implant and only 15 minutes triggering time.