Development of a drug-eluting microstent for micro-invasive glaucoma surgery

• Main Authors: Siewert Stefan, Pfensig Sylvia, Großmann Swen, Stiehm Michael, Schmitz Klaus-Peter, Schmidt Wolfram, Kohse Stefanie, Wulf Katharina, Grabow Niels, Kopp Franziska, Guthoff Rudolf
• Format: Article
• Language: English
• Published: De Gruyter 2018-09-01
• Series: Current Directions in Biomedical Engineering
• Subjects: glaucoma drainage device; drug-eluting microstent; micro-invasive glaucoma surgery
• Online Access: https://doi.org/10.1515/cdbme-2018-0145

Glaucoma represents the leading cause of irreversible blindness worldwide. Therapeutic approaches are based on the lowering of intraocular pressure (IOP). Micro-invasive glaucoma surgery (MIGS) offers perspectives for implant based IOP-reduction with reduced complication rates compared to conventional surgical approaches. Nevertheless, available devices suffer from complications like hypotony and fibrotic encapsulation. The current work focuses on the development of a minimally invasive implantable drugeluting microstent for the drainage of aqueous humour into suprachoroidal or subconjunctival space. Technical feasibility of a micro-scale resorbable nonwoven for the prevention of hypotony and of a drug-eluting coating for the prevention of fibrosis is assessed. Microstent base bodies with a length of 10 mm and an inner/outer diameter of 0.20 mm / 0.35 mm were manufactured. For the prevention of hypotony, resorbable nonwovens with an adequate flow resistance of 1.543 mmHg/μl min-1 were manufactured in the inflow area of microstents. A drug-eluting coating in the outflow area of microstents was developed based on the model drug fluorescein diacetate. Micro-invasive ab interno implantation of a microstent prototype into suprachoroidal space of a porcine eye post mortem was successfully performed, using an injector device. Future studies will focus on the development of an antifibrotic drug-eluting coating and further in vitro, ex vivo and in vivo testing of the devices.