Magnetic multiwalled carbon nanotubes with controlled release of epirubicin: an intravesical instillation system for bladder cancer.

Background: Traditional intravesical instillation treatment in bladder cancer has limited efficacy, which results in a high frequency of recurrence. Purpose: The aim of this study was to report on an epirubicin (EPI)-loaded magnetic multiwalled carbon nanotube (mMWCNTs-EPI) system for intravesical instillation in place of the current formulation. Methods: The mMWCNTs-EPI system was formulated with carboxylated MWCNTs, Fe3O4 magnetic nanoparticles, and EPI. Features and antitumor activity of the system were investigated. Results: Under the effect of external magnets, the mMWCNTs-EPI system showed sustained release and prolonged retention behavior and better antitumor activity than free EPI. The mMWCNTs-EPI system had higher efficiency in enhancing cytotoxicity and inhibiting proliferation in vitro and in vivo than free EPI. Our studies also revealed the atoxic nature of mMWCNTs. Conclusion: These findings suggested that mMWCNTs are effective intravesical instillation agents with great potential for clinical application.