US-based RiverTech Medical, a Vention Medical Company, has developed precision micro-tubing with variable flexibility for catheter-based medical devices. The micro-tubing offers two to three different stiffnesses and flexibilities within one tubing component for catheter-based medical device procedures such as angioplasty, stent placements, and thrombectomy.

There is a significant need for varying stiffness in catheter designs to allow for optimum flexibility while maintaining the stiffness required to track the catheter to its desired location. In order to achieve ideal performance and processing, the product is comprised of a layer made of Radel polyphenylsulfone (PPSU) resin from Solvay Specialty Polymers.

The flexible precision micro-tubing is made with RiverTech Medical’s proprietary film cast technique which results in small-diameter, thin-walled parts with tight tolerances. The film cast process offers advantages over traditional extrusion by achieving inside diameters down to 0.01016 cm, outside diameter tolerances as tight as ± 0.0003 in., and wall thicknesses as small as 0.00127 cm. This tubing design is built of multiple layers of different polymers and a layer of woven wire material to provide reinforcement for the tubing wall. A fluoropolymer-based material is used for the inner tubing liner to produce a low-friction surface, and a softer thermoplastic is interspersed among the wire reinforcements for flexibility. Solvay’s Radel PPSU is often used to provide strength and stiffness as the 0.00508-cm thick top layer. The high-performance medical-grade polymer delivers strength and melt processability that is comparable to competitive materials like polyimide.

Radel PPSU is a super-tough thermoplastic with high heat resistance, exceptional hydrolytic stability, and excellent chemical resistance. It can withstand over 1,000 cycles of steam sterilisation without significant loss of properties. Radel PPSU is also compliant with ISO 10993-1 for limited exposure, non-implantable applications.