Spray-dried magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin microspheres for sustained release of ofloxacin

A series of magnetic chitosan/Fe3O4/halloysite nanotubes/ofloxacin (CTS/Fe3O4/HNTs/OFL) microspheres was prepared by spray-drying for the sustained release of OFL. CTS was in situ crosslinked by glutaraldehyde in the spray-drying process. The magnetic microspheres were characterized by FT-IR, scanning electron microscopy and thermogravimetric analysis. The magnetic properties, encapsulation efficiency, drug loading and in vitro sustained release properties of the magnetic microspheres for OFL were also evaluated. The CTS/Fe3O4/HNTs/OFL microspheres show superparamagnetic properties and fast magnetic response. The Fe3O4 nanoparticles have a remarkable effect on the surface morphology of the microspheres compared with HNTs. The encapsulation efficiency and the cumulative release are closely related to HNTs and Fe3O4 contents, crosslinking density and CTS concentration. OFL is released from the magnetic CTS/Fe3O4/HNTs/OFL microspheres via anomalous transport.