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

Abstract

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.