Fabrication and characterization of gefitinib-releasing polyurethane foam as a coating for drug-eluting stent in the treatment of bronchotracheal cancer

The purpose of the present study was to develop gefitinib-loaded polymeric foams that can be used as coating of drug-eluting stents for palliative treatment of bronchotracheal cancer. Release of such an anticancer drug from such stent coating can retard tumor regrowth into the bronchial lumen. Gefitinib-loaded polyurethane (PU) foams were prepared by embedding either gefitinib micronized crystals or gefitinib-loaded poly(lactic-co-glycolic acid) microspheres in water-blown films, with up to 10% w/w loading for gefitinib microcrystals and 15% w/w for gefitinib microspheres (corresponding to 1.0% w/w drug loading). Drug-release studies showed sustained release of gefitinib over a period of nine months, with higher absolute release rates at higher drug loading content. By the end of the studied nine month release periods, 60-100% of the loaded gefitinib had been released. Foams loaded with gefitinib-PLGA microspheres at 15% w/w showed accelerated drug release after 4 months, coinciding with the degradation of PLGA microparticles in the PU foam as demonstrated by scanning electron microscopy (SEM). When applied on a nitinol braided bronchotrachial stent, PU coatings with gefitinib microspheres showed similar mechanical properties as the drug-free PU coating, which indicated that the loading of microspheres did not affect the mechnical properties of the PU foams. In conclusion, we have fabricated drug-loaded PU foams that are suitable for bronchotracheal stent coating

Gefitinib/gefitinib microspheres loaded polyurethane constructs as drug-eluting stent coating

One of the complications of bronchotracheal cancer is obstruction of the upper airways. Local tumor resection in combination with an airway stent can suppress intraluminal tumor (re)growth. We have investigated a novel drug-eluting stent coating for local release of the anticancer drug gefitinib. A polyurethane (PU) sandwich construct was prepared by a spray coating method in which gefitinib was embedded between a PU support layer of 200 μm and a PU top layer of 50–200 μm. Gefitinib was either embedded in the construct as small crystals or as gefitinib-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres (MSP). The drug was incorporated in the PU constructs with high recovery (83–93%), and the spray coating procedure did not affect the morphologies of the embedded microspheres as demonstrated by scanning electron microscopy (SEM), confocal laser scanning microscopy and fluorescence microscopy analysis. PU constructs loaded with gefitinib crystals released the drug for 7–21 days and showed diffusion based release kinetics. Importantly, directional release of the drug towards the top layer, which is supposed to face the tumor mass, was controlled by the thicknesses of the PU top layer. PU constructs loaded with gefitinib microspheres released the drug in a sustained manner for > 6 months indicating that drug release from the microspheres became the rate limiting step. In conclusion, the sandwich structure of drug-loaded PLGA microspheres in PU coating is a promising coating for airway stents that release anticancer drugs locally for a prolonged time

Gefitinib/gefitinib microspheres loaded polyurethane constructs as drug-eluting stent coating

One of the complications of bronchotracheal cancer is obstruction of the upper airways. Local tumor resection in combination with an airway stent can suppress intraluminal tumor (re)growth. We have investigated a novel drug-eluting stent coating for local release of the anticancer drug gefitinib. A polyurethane (PU) sandwich construct was prepared by a spray coating method in which gefitinib was embedded between a PU support layer of 200 μm and a PU top layer of 50–200 μm. Gefitinib was either embedded in the construct as small crystals or as gefitinib-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres (MSP). The drug was incorporated in the PU constructs with high recovery (83–93%), and the spray coating procedure did not affect the morphologies of the embedded microspheres as demonstrated by scanning electron microscopy (SEM), confocal laser scanning microscopy and fluorescence microscopy analysis. PU constructs loaded with gefitinib crystals released the drug for 7–21 days and showed diffusion based release kinetics. Importantly, directional release of the drug towards the top layer, which is supposed to face the tumor mass, was controlled by the thicknesses of the PU top layer. PU constructs loaded with gefitinib microspheres released the drug in a sustained manner for > 6 months indicating that drug release from the microspheres became the rate limiting step. In conclusion, the sandwich structure of drug-loaded PLGA microspheres in PU coating is a promising coating for airway stents that release anticancer drugs locally for a prolonged time