12/1/16 Drug delivery has remained a rapidly growing area of the medical device industry, that include medical devices that enable controlled internal release of drugs to targeted surgical sites presenting enormous opportunities.
Researchers are using wet fiber extrusion in implantable textile structures for medical device applications. These fibers allow for improved device performance resulting in faster healing, improved patient compliance, and lower negative outcomes at relatively low cost by adding drug-delivery capabilities to new and existing devices across a variety of applications. Though this process is promising, the types of drugs able to be successfully loaded to fibers while remaining viable have been limited by the mechanics of the extrusion process. The high temperatures required exceed the temperature tolerance of a majority of pharmaceutical and biological therapeutic agents. But with the emergence of alternative wet extrusion methods of enabling drug loading of fibers at room temperature for use in implantable devices for localized drug delivery within the body, this issue may be overcome.
The controlled process of wet fiber extrusion yields more uniform size distribution than the distribution typically found in other formats. Multi-layered, co-axial fibers are readily produced with each layer containing a unique pharmaceutical and polymer combination, resulting in tailored release kinetics for multiple pharmaceuticals in a single fiber. The localized drug delivery capability of these fibers enables medical device designers to orchestrate the body’s response to the device. Depending on the choice of drug, it is even possible to mitigate unwanted reactions and promote desired responses. Pharmaceutical-loaded fibers also provide excellent drug delivery depots where precise placement within the body is desired, as within a solid tumor.
Fibers can be extruded in monofilament, hollow, bi-component (core-sheath), gel-center filled formats, and also as flat, rectangular or ribbon shapes. Unlike traditional pharmaceutical delivery formats such as microspheres and nanoparticles, these fibers can provide both mechanical and pharmacological support from the same device – an incredible advantage over other modes of pharmaceutical delivery. Another use of drug-loaded wet-extruded fibers is they provide excellent scaffolding for tissue engineering and regenerative medicine applications. It is otherwise impossible to provide pharmaceutical delivery localized to the cells on and around a single specific fiber. This micro-control of pharmaceutical release provides a significant step forward in research in implantable pharmaceutical delivery.
The use of biodegradable fibers offers several other unique advantages over traditional pharmaceutical delivery formats. A long cylindrical geometry can provide a slower pharmaceutical release rate than a spherical geometry of the same radius, resulting in an inherently longer therapeutic window for similar pharmaceutical concentrations.
Breakthroughs in fiber extrusion are now making it possible to load the widest variety of viable pharmaceuticals and biologics ever for implantable drug delivery. Allowing these agents to be delivered internally directly at targeted surgical sites has the potential to revolutionize the way many medical applications can be approached — presenting new opportunities for medical device manufacturers; providing doctors and surgeons with greater options for treatment approaches; and ultimately may improve patient outcomes in many cases.