Matter of substance: New materials for medical devices
Alexander Silvestre, Norbert Niessner, Michiel Verswyvel, Bernd Elbert and Cliff Pettey, Ineos Styrolution, examine styrenic solutions for the medical device sector.
Healthcare application providers are torn in two directions when it comes to working with new materials. On the one hand, they would like to build superior devices to existing ones – or all new applications that cannot be realised with existing materials. On the other hand, every new material requires lengthy approval processes.
As a result, new materials should provide a significant new value proposition to justify the investment in new applications and devices.
Two main factors drive the value proposition of a new material in the healthcare industry.
The first factor is related to the actual physical and chemical properties of the new material. These properties decide if a product is capable of serving a defined purpose. Details are listed in technical data sheets. For styrenic materials, for example, the data sheet may contain dozens of mechanical, thermal, rheological and other properties.
An important material property for many materials in the medical industry is the chemical resistance against drug media. Residual monomer and additive release into the media needs to be kept to a minimum, and low adsorption and absorption of targeted drugs are very important drivers when selecting new materials. Styrenic materials traditionally show a very good performance in this area and Styrolux, an Ineos Styrolution SBC material, excels with a strong resistance against drug media.
In addition to the material properties, application providers also pay attention to the ease-of-use of working with a certain material. ‘Ease-of-use’ describes a long list of criteria that may be different from material to material and from application provider to application provider. The list ranges from processability of the material all the way to services provided by the material provider. It includes topics like product quality, availability of the material (eg. long-term availability and early notification of change, reliable deliveries), logistical aspects and many more criteria. Global application providers may have additional requirements such as sourcing across different regions at identical quality.
In this article, we look at two examples of new materials responding to healthcare application providers’ needs. The first project has been completed only recently. It is a perfect example of providing a solution to the industry that meets expectations – and is adopted almost instantly. The second example discusses a future scenario of a certain application.
Fibre filled ABS
Earlier this year, INEOS Styrolution brought a new ABS material to market that was the first of its kind (see also reference 1): A glass fibre-filled styrenic ABS (acrylonitrile butadiene styrene) grade, especially for medical applications. The new material, called Novodur HD M203FC G3, does impress with its mechanical properties such as stiffness, impact strength and dimensional stability, its high flowability (melt volume rate, 220 °C/10 kg, ISO 1133: 18cm3/10 min) allowing for an excellent processability – and, last but not least, the fact that it is compliant to regulatory standards in the healthcare industry. Novodur HD M203FC G3 meets the requirements of European and Japanese pharmacopoeia and it has been tested according to the USP Class Biological Reactivity Tests Class VI and relevant 10993 standards.
This new material was immediately embraced by the industry and a first application became available only briefly after the material was introduced (see image 1 and reference 2).
While the material properties alone were convincing already, the regulatory approval and the fact that the material is offered with Ineos Styrolution’s signature “Full Service HD Package” (which includes an up to 36 months notification of change) contributes to the material’s attractiveness and reduced risk for application providers.
All-styrenic IV set
Healthcare application providers constantly look for alternatives for commonly used materials. Having alternative solutions at hand does not only allow exploring new properties or new functionalities. They also provide a safety net if tighter regulations demand shifts towards new solutions.
Ineos Styrolution has proven that styrenics make ideal materials for a range of healthcare applications – and the company is constantly growing the number of dedicated solutions for the healthcare sector. Today, Ineos Styrolution is aiming at developing the first all-styrenics IV set. Being a dedicated supplier for styrenic polymers in the healthcare industry, the company is bundling its styrenics IV activities within its global healthcare team, led by Alexander Silvestre.
Styrenics provide several properties resulting in a higher efficiency and lower cycle times. These may be key for an application provider. The key benefits of styrenics include
- easily bonded to other materials
- a low density resulting in more output
- excellent flowability and processability
- high flow grades
- lower processing temperatures
- limited to no pre-drying
Styrenics provide the additional benefit of clean incineration after use.
Overall, it can be said that the Ineos Styrolution materials such as Styrolux and Styroflex show properties that are well balanced making them ideal solutions for IV sets. In addition to the above list of properties, the materials show an excellent behaviour in drug absorption tests, in particular in comparison to traditionally used materials. This includes, for example, a very low absorption rate for insulin and overall low absorption values for typical drug molecules.
Ineos Styrolution has a strong presence in this field, with solutions such as
- MABS (Terlux), SMMA (NAS) and MBS (Zylar), highly transparent materials for connectors
- dedicated Styrolux grades, specifically designed for the use in drip chambers in IV sets
- the above mentioned Novodur HD M203FC G3 for demanding applications like spikes and applications requiring structural stability
- Polystyrene and ABS solutions for roller clamps
In addition to these existing materials, Ineos Styrolution is currently working on material solutions for the flexible parts of the IV set.
- Materials for tubing are under development using SBC (styrene-butadiene block copolymer) based solutions (see references 3 and 4). Important properties for good tubing materials include a high transparency for visual inspection, good resistance against kinking during bending to ensure continuous drug feeding and good resilience. The recent integration of the K-Resin business into Ineos Styrolution’s market leading styrenic portfolio leverages both companies’ respective strong technical heritages to create new and innovative customer solutions for medical applications.
- Materials for IV bags require film featuring a good puncture resistance, good transparency and they must be able to be sterilised. The materials also need to feature a defined shelf life, which is due to high barrier properties. Another aspect is the need for regulatory approved stabilisation and additive (eg. waxes) packages. First developments have been reported (see reference 5). Ongoing research show that it is crucial to combine puncture resistance with high temperature resistance and certain barrier properties (provided by polyolefins and cycloolefins).
Norbert Niessner, global head of research and development/ intellectual property at Ineos Styrolution, summarises the ongoing efforts.
“Our development team is closely linked not only to state-of-the-art technology to develop and produce innovative styrenics based materials, we are also in close contact with leading medical OEMs, thanks to the global presence of our healthcare team. They constantly provide us with valuable insights into the industry’s needs.”