Electrosprayed Magnetic Poly(butyl methacrylate- <i>co</i> -(2-dimethylaminoethyl) methacrylate- <i>co</i> -methyl methacrylate)/Iron Oxide Microparticles for Efficient Curcumin Delivery

This study successfully optimized the electrospraying process of poly-(butyl methacrylate-<i>co</i>-(2-dimethylamino)-ethyl methacrylate-<i>co</i>-methyl methacrylate) (P-(BMA-<i>co</i>-DMAEMA-<i>co</i>-MMA)) copolymer solutions containing curcumin (CUR) and iron oxide (Fe₃O₄) for the production of microparticles serving as carrier systems. P-(BMA-<i>co</i>-DMAEMA-<i>co</i>-MMA) is a cationic copolymer synthesized via free radical polymerization of the monomers N,N-dimethylaminoethyl methacrylate (DMAEMA), methyl methacrylate (MMA), and butyl methacrylate (BMA). By combining a pH-responsive poly-(methacrylate) matrix with superparamagnetic Fe₃O₄, this work addresses current limitations of CUR delivery systems (burst release and low drug loading). It provides a dual-stimuli platform for controlled release. P-(BMA-<i>co</i>-DMAEMA-<i>co</i>-MMA) solutions, with or without CUR and Fe₃O₄, were prepared in ethanol/N,N-dimethylformamide (EtOH/DMF) and processed via electrospraying. The copolymer concentration ranged from 10 to 30% (w/v) in EtOH/DMF (80/20 and 20/80 (v/v) ratios), and the presence of CUR (10, 20, and 30% (w/w)) and Fe₃O₄ (1-8% (w/w)). The influence of solution properties (viscosity, electrical conductivity, and surface tension) and processing conditions on particle morphology and drug loading was evaluated. The electrosprayed microparticles were analyzed using scanning electron microscopy (SEM), attenuated total reflectance Fourier-transform infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Loading a significant amount of CUR in the microparticles was possible due to the solubility of CUR and copolymer in the EtOH/DMF mixture. The CUR crystallinity was significantly reduced compared to the loaded CUR. Controlled release studies of CUR were conducted and the sample prepared from a mixture containing 10% (w/v) of copolymer (COP), 20% (w/w) of CUR, and 8% (w/w) of Fe₃O₄ (sample COP10/CUR20/Fe₃O₄(8)), when exposed to an external magnetic field, significantly reduced the CUR release rate from 27.5%/h to 1.16%/h at pH 3.8 and 6.42%/h to 0.48%/h at pH 6.8. Release kinetics analysis indicated that the Korsmeyer-Peppas model best fitted the experimental data. These results demonstrate that Fe₃O₄-containing P-(BMA-<i>co</i>-DMAEMA-<i>co</i>-MMA) microparticles exhibit dual pH-responsive and magnetically responsive properties, resulting in a significant reduction of burst release and providing spatially and temporally tunable CUR delivery.