Magnetic-responsive microparticles with customized porosity for drug delivery

Abstract

Several magnetic-polymer particle systems have been developed in recent times to facilitate improved targeting, localization and controlled delivery of active compounds. The main focus for such systems has centered on solid or core–shelled (non-porous) particles incorporating drug and magnetic features into individual polymeric carriers. In this study porous particles hosting drug (indomethacin) and magnetic Fe₃O₄ nanoparticles (NPs) were prepared, using a single needle one-step electrospraying technique via a non-solvent collection method. The resulting particles were characterized using scanning electron microscopy, energy dispersive spectra analysis, infrared spectroscopy, X-ray diffraction and Brunauer–Emmett–Teller specific area measurements. Analysis confirmed the incorporation of Fe₃O₄ NPs within the microspheres (∼20 μm in diameter), which could be further modified and tuned for porosity, magnetic response and thus release of incorporated active compounds. In vitro drug release for both porous and solid (non-porous) particle systems demonstrated high drug encapsulation efficiencies, ranging from ∼75% to 98%. Furthermore, the one-step synthesis process also suggested that the drug incorporated exists in an amorphous state, which is highly beneficial for drug absorption. Releases studies indicate a short drug burst period followed by a prolonged phase of dissolutive release. Based on mathematical fitting to both Higuchi and Korsmeyer–Peppas model, a release mechanism based on Fickian diffusion was confirmed. Through external alternating magnetic fields (AMF, 40 kHz), the drug release rate from magnetic-responsive microspheres was enhanced, facilitating drug release over the established Fickian process. This work demonstrates a versatile and efficient method for the development of drug-magnetic porous microparticles via a one-step electrospraying technique that enables controlled drug targeting, localization and tunable release.