Rational design of drug-eluting stents via electrospray and in vivo evaluation of preventing oesophageal stricture

Abstract

Stent-induced restenosis limits the clinical use of stents in the palliative treatment of oesophageal stricture. To prevent such secondary tissue hyperplasia, novel paclitaxel-coated stents were developed using electrospray in this study. Automatic electrospray could achieve precise control of formulation and coating pattern. After preparation, polyurethane film still maintained great mechanical properties at high drug-loading (≥20%), with maximum 6-fold elongation and over 20 MPa tear strength. Furthermore, drug-loading film kept the intactness and tight attachment with the stent throughout the experiment. Drug-release kinetics was similar between in vitro and in vivo tests. Approximately 50% paclitaxel was released in the early stage, followed by a sustained release that could maintain the local therapeutic concentration for 6 weeks or more. Rabbit was chosen as the animal model for the in vivo evaluation of preventing oesophageal stricture. Compared with non-drug coating stents, paclitaxel-eluting stents were safe and effective against tissue hyperplasia secondary to stent deployment. These results suggest that this paclitaxel-eluting stent and versatile electrospray technique would provide a promising strategy in the management of malignant and refractory benign oesophageal stricture.