Biodegradable PLA Double Emulsion Microspheres for Magnetically Guided Drug Delivery of 5-Fluorouracil

This study describes a carrier having submicron, uniform and non-aggregated poly lactic acid (PLA) spheres loaded with the anticancer drug 5-fluorouracil (5FU) and with 9 nm superparamagnetic iron oxide nanoparticles (SPIONs) for magnetically guided drug delivery and local controlled release. Using a water/organic/water (w/o/w) double-emulsion process, we produced uniformly spherical microparticles smaller than 2 µm in diameter with well-dispersed SPIONs that retained superparamagnetic behavior after encapsulation. 5FU loading efficiency was determined to be 94%. Biological activity and chemical integrity was confirmed for the 5FU released from the product. Drug release kinetics showed faster release within the first day followed by sustained, slower release over 63 days with a cumulative release reaching 70% of loaded drug. Drug release was faster at 37°C compared to 21°C. PBS at pH 7.4 and 5.4 promoted faster release than did distilled water at pH 7.0. Release was prolonged from these PLA systems compared to other systems employing PLGA. This research introduces a rigorously optimized microcarrier system distinguished by sub-2-µm superparamagnetic PLA or PLGA microspheres of uniform morphology containing phase-dispersed SPIONs and exhibiting long-term controlled release, offering a transformative framework for magnetically directed drug delivery using high-gradient systems such as Halbach arrays.