Magnetic microspheres based on pectin coated by chitosan towards smart drug release

• A facile protocol enabled to prepare microspheres of pectin/magnetite coated by chitosan. • The magnetic microspheres were used to encapsulated metamizol, a drug model. • In vitro experiments revealed that the drug release from the microspheres is pH-dependent. • The drug release is boosted under neutral conditions compared to acidic conditions. • An external magnetic field enhanced the cumulative drug release in both tested media. This study reports the preparation of microspheres of pectin and magnetite nanoparticles coated by chitosan to encapsulate and deliver drugs. Magnetic-pectin microspheres were obtained by ionotropic gelation followed by polyelectrolyte complexation with chitosan. Characterization data show that magnetite changes the physicochemical and morphological properties of the microspheres compared to the non-magnetic samples. Using metamizole (Mtz) as a drug model, the magnetic microspheres showed appreciable encapsulation efficiency (85 %). Release experiments performed in simulated gastric (pH 1.2) and intestinal (pH 6.8) fluids suggested that the release process is pH-dependent. At pH 6.8, the Mtz release is favored achieving 75 % after 12 h. The application of an external magnetic field increased the release to 91 % at pH 6.8, indicating that the release also is magnetic-dependent. The results suggest that the magnetic microspheres based on pectin/chitosan biopolymers show the potential to be used as a multi-responsive drug delivery system.