Novel superparamagnetic Fe₃O₄ nanoparticles coated with polyethylene glycol for controlled release of levodopa: synthesis, characterization and RSM optimization

Abstract

Levodopa (L-DOPA), an effective treatment for Parkinson’s disease, increases dopamine levels in the brain and improves the life quality of patients. This research presents a novel drug nanocarrier for the controlled release of L-DOPA using magnetic Fe₃O₄ nanoparticles (NPs) functionalized with polyethylene glycol. This strategy optimizes the nanocarrier’s capacity to load L-DOPA efficiently, transfer it precisely, and improve clinical efficacy in the treatment of Parkinson’s disease. Moreover, this paper indicates that the coating process of Fe₃O₄ NPs can lead to a sustained and slow release of L-DOPA and enhance the dispersibility of the proposed carrier. The final polymer-coated carrier is characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, dynamic light scattering, X-ray diffraction, and field emission scanning electron microscopy coupled with energy-dispersive X-ray analysis devices. Three influential experimental variables, including pH (4), contact time (7 min), and temperature (25°C), are optimized using the RSM/CCD approach. The polymer-coated Fe₃O₄ particles produced indicated in vitro release values of 42.15%, 62.18%, and 88.53% for L-DOPA in simulated intestinal fluid (pH = 7.4) after 0.5, 6, and 72 h, respectively. The results of nonlinear models for both kinetic and adsorption isotherms showed a good match with the pseudo-second-order and Langmuir models. The thermodynamic study confirmed the spontaneity and feasibility of the proposed strategy by confirming the exothermic and entropy-driven nature of L-DOPA adsorption. Computational modeling of the results suggested Higuchi and Fickian diffusion mechanisms for the kinetics of L-DOPA release from the carrier. The findings suggest that the proposed approach could be a promising option for functional L-DOPA delivery in therapeutic applications.