Capillarity-induced loading and release of chemotherapeutic agent within multi-wall carbon nanotubes

The aim of this study was to investigate the loading and release behavior of 10-hydroxycamptothecin (HCPT) based on carboxylic multi-wall carbon nanotubes (c-MWCNTs) as drug carrier. C-MWCNTs were prepared by strong acid treatment and characterized by elemental analysis, Raman spectra, scanning electron microscopy and thermogravimetric analysis. HCPT was loaded within c-MWCNTs cavity by employing a wet-chemical method with loading amount approximately 120 mg/g. The location of the HCPT was confirmed by high-resolution transmission electron microscopy. Results of in vitro release revealed that cumulative release percentage of HCPT could amount to over 35 % at pH 5.0 buffer solutions from HCPT-loaded c-MWCNTs compared with less than 5 % at pH 7.4 buffer solutions over a monitoring period of 96 h. Our results revealed c-MWCNTs can be employed as a potential acid labile anti-tumor drug carrier.