Abstract: Objective To prepare a targeted antitumor drug delivery system using large-inner-diameter multi-walled carbon nanotubes (LID-MWCNTs) for sustained release and to study its performance. Methods LID-MWCNTs were puri⁃ fied and oxidized，then use nanocarriers and USTs as homologous blockers. Folic acid and fluorescent labels were conjugat⁃ ed onto the external surfaces of nanocarriers. CDDP (cisplatin) was encapsulated and ultrashort tubes (USTs) were employed to block the drug entry/exit paths. The microstructure of resulted drug delivery system (DDS) was observed, while drug load⁃ ing efficiency and drug release profile in vitro were determined. The tumor-targeting property and cytotoxicity of DDS were also assessed. Results LID-MWCNT based sustained release targeted drug delivery system was established. Drug loading efficiency of CDDP@UST-FA-LID-MWCNTs was as high as 70.97%. A typical biphasic sustained release pattern was dem⁃ onstrated, and the accumulating release time was 18 h. DDS exhibited a certain kind of tumor-targeting property, and inhibit⁃ ed proliferation of tumor cells in a dose-dependent manner. Conclusion CDDP@UST-FA-LID-MWCNT drug delivery system exhibited an improved drug loading efficiency and a sustained drug release profile. It could specifically target the tu⁃ mor cells and had a significant antitumor effect.

Key words: nanotubes, carbon, cisplatin, antineoplastic agents, drug carriers, delayed-action preparations, multiwalled carbon nanotubes, property, release profile