Magnetically stimulated ciprofloxacin release from polymeric microspheres entrapping iron oxide nanoparticles

Abstract

To extend the external control capability of drug release, iron oxide nanoparticles (NPs) encapsulated into polymeric microspheres were used as magnetic media to stimulate drug release using an alternating magnetic field. Chemically synthesized iron oxide NPs, maghemite or hematite, and the antibiotic ciprofloxacin were encapsulated together within polycaprolactone microspheres. The polycaprolactone microspheres entrapping ciprofloxacin and magnetic NPs could be triggered for immediate drug release by magnetic stimulation at a maximum value of 40%. Moreover, the microspheres were cytocompatible with fibroblasts in vitro with a cell viability percentage of more than 100% relative to a nontreated control after 24 hours of culture. Macrophage cell cultures showed no signs of increased inflammatory responses after in vitro incubation for 56 hours. Treatment of Staphylococcus aureus with the magnetic microspheres under an alternating (isolating) magnetic field increased bacterial inhibition further after 2 days and 5 days in a broth inhibition assay. The findings of the present study indicate that iron oxide NPs, maghemite and hematite, can be used as media for stimulation by an external magnetic energy to activate immediate drug release.

Recent Developments in Antibacterial Therapy: Focus on Stimuli-Responsive Drug-Delivery Systems and Therapeutic Nanoparticles

“…The magnetothermally stimulated release of antibiotics from drug-delivery vehicles has been demonstrated using superparamagnetic iron oxide nanoparticles (SPIONs) [31,32,33,34]. SPIONs consist of cores made of iron oxides that can be targeted to the required area using external magnets.…”

Stimuli‐Responsive Release of Antimicrobials Using Hybrid Inorganic Nanoparticle‐Associated Drug‐Delivery Systems

“…Magnetothermal stimulated release of antibiotics from drug‐delivery vehicles has been predominantly demonstrated using SPIONs . SPIONs are composed of ferri‐ or ferromagnetic‐materials, meaning they contain electrons with an ensemble average of either up or down spin states.…”

“…The magnetothermal response of a SPION may differ between different forms of iron oxides and can affect the drug release efficiency of a system. For example, although maghemite (γ‐Fe 2 O 3 ) and hematite (α‐Fe 2 O 3 ) both exhibit a large magnetic moment within an external magnetic field, their efficiency at modulating stimulated release of drugs has been found to differ substantially . This has been demonstrated through the co‐loading of either maghemite or hematite NPs with ciprofloxacin (CIP) in poly(caprolactone) microspheres.…”

“…Magnetothermal stimulated release of antibiotics from drugdelivery vehicles has been predominantly demonstrated using SPIONs. [65,[76][77][78] SPIONs are composed of ferri-or ferromagnetic-materials, meaning they contain electrons with an ensemble average of either up or down spin states. NPs with diameters below 50 nm can randomly flip magnetic spin in the absence of an external field providing an apparent average magnetization of zero, otherwise known as a superparamagentic state.…”

“…For example, although maghemite (γ-Fe 2 O 3 ) and hematite (α-Fe 2 O 3 ) both exhibit a large magnetic moment within an external magnetic field, their efficiency at modulating stimulated release of drugs has been found to differ substantially. [76] This has been demonstrated through the co-loading of either maghemite or hematite NPs with ciprofloxacin (CIP) in poly(caprolactone) microspheres. After exposure to an alternating magnetic field for 1 day, the maghemite-loaded microspheres exhibited a higher release of CIP at 78% (w/w) compared to the 36% release observed with the hematite-loaded microspheres.…”