Solvay: Recent Medical Applications of Sulfone Polymer Technology

Solvay Specialty Polymers, part of Belgian chemical and plastics manufacturer Solvay, has announced two medical applications for its sulfone polymer technology—an implantable drug infusion system made from PSU and a highly durable non-implantable impeller for blowers and fans made from PPSU.

Implantable drug infusion system

An Italian designer and manufacturer of implantable dental and infusion systems, Plan 1 Health, has developed implantable catheter ports made from polysulfone (PSU) resin. The resin was chosen thanks to its biocompatibility, dimensional stability, and MRI compatibility. The brand of PSU used is Eviva, manufactured by Solvay Specialty Polymers and part of that manufacturer's Solviva Biomaterials line for use in implantable medical devices. The resin was used to improve a previous all-titanium model of the port. The port is sold under the Healthport brand.

The new port system, the Plastics Low Profile (PLP) model, is said to be versatile and highly reliable for delivery of drugs, antibiotics, and nutrient therapy solutions. Furthermore it is lightweight and cost-effective, and features a low-profile PSU housing that is suitable for all patients. A titanium inner chamber avoids damage induced by the needle tip and avoids interactions between Eviva PSU and the drug. A large self-sealing septum facilitates location during skin palpation and reduces the risk of puncture concentration. A transparent polyurethane connector allows a rapid, safe, and reversible connection of the catheter.

The catheter port is a multi-piece assembly consisting of an injection moulded housing and ring component, both made of Eviva PSU, and a titanium inner chamber. The PLP model is lighter and more cost-effective than previous all-titanium versions which require more expensive manufacturing techniques, according to Alessandro Rainis, product manager for Plan 1 Health. The titanium chamber is fixed between the two plastic components that are ultrasonically welded together.

Eviva PSU is a transparent polymer that offers toughness and strong biocompatibility. The material maintains its dimensional tolerance right out of the mould and requires no machining. It is a rigid thermoplastic that doesn’t absorb fluids and is artifact-free for effective MRI imaging.

“We’ve been very pleased to work with Plan 1 Health as they develop advanced approaches for implantable infusion systems,” said Shawn Shorrock, global healthcare market manager for Solvay Specialty Polymers. “The ongoing acceptance of Eviva PSU has validated our approach to the implantable infusion market and we’re encouraged by the momentum we’ve generated.”

The manufacturing site for Eviva PSU and other Solviva Biomaterials in Alpharetta, Georgia, USA, is ISO13485 registered and, according to Solvay, the relevant aspects of current Good Manufacturing Practices (GMP) are also applied. Solvay’s Solviva Biomaterial manufacturing processes are carefully validated and enhanced controls provide product traceability. In addition, all materials are tested in an ISO 17025 accredited lab. Based on biocompatibility testing, Eviva PSU demonstrates no evidence of cytotoxicity, sensitisation, irritation or acute systemic toxicity.

The catheter ports—sold to medical device distributors in Europe, Asia, and India—have earned the CE (Conformité Européenne) mark which demonstrates compliance with numerous EC directives, enabling the product to be sold throughout the EU. Plan 1 Health is also exploring the option of seeking 510(k) clearance from the US Food & Drug Administration (FDA) and entering the US market.

Impeller for ventilators and continuous positive airway pressure (CPAP) machines

Radel polyphenylsulfone (PPSU) resin has been chosen for use in a high-pressure impeller developed by MUS International, a leading Chinese manufacturer of high-performance miniature blowers and fans. The material was chosen for its high strength, toughness, and high stress crack resistance.

The high-performance thermoplastic replaces competitive materials such as modified polyphenylene ethers (PPE), offering improved stress crack performance.

MUS International also selected Radel PPSU for its biocompatibility for use in a range of medical applications. The company’s blowers are used in medical products such as ventilators and Continuous Positive Airway Pressure (CPAP) machines for sleep apnea patients, along with fuel cells, air sensors, packaging machines, and other industrial uses.

MUS International said it plans to use Radel PPSU for injection molded impellers for most of its range of blower products. The company has a broad offering of small high-performance centrifugal blowers based on brushless DC motors for extra-long life. They also feature hall-effect sensors, high-quality dual ball bearings, and internal temperature sensors. An impeller can operate up to 60,000 rpm in some blower products, according to MUS International. The impeller’s intricate design has defined features which maximise air handling and circulation.

“Radel PPSU played a major role in improving the performance of our high-pressure impellers,” said J R Schenk, principal of Fisaga Technologies based in California. Fisaga is the US representative and technology development firm for MUS International. “We were also very pleased with the level of support we received from Solvay both in the US and China", he added. The impellers and blowers are engineered in the USA and manufactured in China.

The injection moulded impellers range in size from 34 mm to 48 mm in diameter. They consist of an impeller base and a top section which is ultrasonically welded to the base.

According to Solvay, 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. It is inherently flame retardant and is resistant to bases and other chemicals. Radel PPSU is also compliant with ISO 10993-1 for limited exposure, non-implantable applications.

Solvay Specialty Polymers is a global leader in the development of sulfone polymer technology, having launched the Udel brand of polysulfone nearly 45 years ago.

Expansion of Availability of KetaSpire PEEK and AvaSpire PAEK

On June 18, 2013, Solvay Specialty Polymers announced a number of supply chain initiatives to expand the availability of its KetaSpire polyetheretherketone (PEEK) and AvaSpire polyaryletherketone (PAEK) products. Key components of this initiative include the deployment of new production assets in China for production of KetaSpire and AvaSpire compounds and the creation of new distribution centres for KetaSpire, AvaSpire, and Torlon polyamide-imide (PAI) resins in Singapore, China, Japan, and South Korea. The added distribution centers complement the existing warehouse network in Europe, the Americas, and other regions of the world.