Development of nanofiber coated indomethacin-eluting stent for tracheal regeneration

In the case of tracheal rupture or stenosis, most effective way is to insert a commercially available metal stent. However, the implantation often causes a fever or a pain on the contact surface between trachea and the stent. And also the metal stent should be removed after a certain time implantation. Thus, we developed a functional tracheal drug eluting stent consisting of indomethacin, a nonsteroidal anti-inflammatory drug (NSAID), loaded nanofibers on a bare metal stent. To control the drug release kinetics and enhancement of mucosal regeneration, gelatin and PLCL were coated layer by layer on a metal stent by an electrospinning method. Indomethacin was loaded in the gelatin layer by soaking and drying method (0.1, 0.5, and 1 wt% in ethanol for 10 min). The morphology of functional drug eluting tracheal stent was characterized by scanning electron microscope (SEM). And mechanical properties of the constructs such as air leak pressure, ultimate tensile stress, and modulus were calculated and evaluated. Drug release was performed by a high performance liquid chromatography (HPLC). Stably coated gelatin and poly(L-lactide- co-epsilon-caprolactone) (PLCL) nanofibers were observed by SEM. Bi-layered nanofibers-coated stent showed enough mechanical properties as a tracheal stent, which confirmed by a custom-designed air leak mechanical test. For indomethacin loading on a stent, stent was immersed in a series of drug solutions (different concentrations) for 10 min. At the result of HPLC, total amounts of indomethacin on a stent were approximately 77, 323, and 670 ug/stent, respectively. Time dependent drug release kinetics of the tracheal stent showed a sustained release profile regardless of indomethacin content. Thus, functionally designed nanofiber coated tracheal stent with anti-inflammatory drug may be useful for tracheal regeneration.