(440b) Processing of Superparamagnetic Iron Oxide Nanoparticles by the Dense Gas Technology

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained an important role in recent developments in drug targeting, cancer therapy and biomedical imaging. Intense research efforts have been directed toward the application of SPIONs as drug carriers in magnetic drug targeting, as contrast agents in magnetic resonance imaging (MRI) and as heating mediators in hyperthermia treatments. Surface modification of SPION is required to improve their stability, biocompatibility and therapeutic efficacy. Surface modification of SPION is usually achieved by applying a biocompatible polymeric coating. Current coating processes for SPION involve in-situ polymerization of deposited monomers. In situ-polymerization presents the drawbacks of presence of residual solvents in the final product and need of intensive post-processing. The dense gas technology can be an attractive option to conventional coating processes for SPION. The technology of dense gases is able to generate solvent-free products by applying single-step processes. Moreover, it has a proven ability to produce submicron particles with narrow particle size distribution, which is a critical aspect in different biomedical applications of SPIONs. Magnetite-polymer composite below 1μm has been produced by Aerosol Solvent Extraction System (ASES) using carbon dioxide as the antisolvent. Biocompatible pH-responsive polymer Eudragit® S100 was used in order to prepare multi-responsive composite with potential applications as oral contrast agents for gastrointestinal MRI and as drug carriers for colon specific delivery. Effects of different processing parameters on magnetite content, product morphology, particle size, encapsulation efficiency and magnetic properties are presented.