Gemcitabine-releasing polymeric films for covered self-expandable metallic stent in treatment of gastrointestinal cancer

Non-vascular drug-eluting stents have been studied for the treatment of gastrointestinal cancer and cancer-related stenosis. In this study, we designed and evaluated a gemcitabine (GEM)-eluting covered nonvascular stent. Polyurethane (PU)/polytetrafluoroethylene (PTFE) film was selected for the drug loading and eluting membrane. The membrane was fabricated by dip-coating on a Teflon bar (∅; 10 mm), air-dried, peeled off and applied to a self-expanding Nitinol stent. Various amounts of poloxamer 407 (PL, Lutrol® F127, BASF) (8%, 10%, or 12% of PU by weight) were added to control the release of GEM from membranes. The membrane containing 12% PL (GEM-PU-PL12%) showed the most favourable release properties; 70% of the loaded GEM released within 35 days, including the 35% released during the initial burst. The biological activities of GEM-PU-PL12% were evaluated using human cholangiocarcinoma cells (SK-ChA-1). GEM-PU-PL12% most efficiently inhibited the proliferation of cholangiocarcinoma cells and most highly induced pro-inflammatory cytokines (TNF-α, IL-1β and IL-12) and p38 MAPKs in the cells. Subtumoural insertion of the GEM-PU-PL12% membrane more efficiently inhibited the growth of CT-26 colon cancer than other membranes. In this study, the GEM-eluting metal stents covered with PU-PL12% showed considerable feasibility for the treatment of malignant gastrointestinal cancer as well as cancer-related stenosis.