Defining the standard for medical grade polymers
Siobhan Bastiansen, Velox, explains why material suppliers as well as device manufacturers would benefit from clarification and shows how specialised medical polymer producers have risen to the challenge to create indispensable value for processors and OEMs.
Medical device development is a long and complex undertaking, with strict compliance regulations, long-term tests, quality checks and certifications. However, the industry has yet to answer one seemingly simple question: What is a ‘medical-grade’ polymer? The Association of German Engineers, VDI, has embarked on defining a standard, with the first draft being presented at the VDI congress in Friedrichshafen in April.
Polymers have been used in the healthcare and medical industry for decades. Today, an estimated 50 % of all materials used in medical device manufacturing consist of plastics. However, when it comes to the right polymer choice for a specific medical or pharmaceutical application, things can get complicated. Despite strict international and national regulations as well as demanding requirements for medical polymers, one extra difficulty in this choice is the fact that there has been no universally accepted definition of ‘medical-grade’ polymers so far.
Application restrictions for polymer suppliers
As a result, uncertainties have prevailed both on the part of medical device manufacturers as well as of polymer suppliers. After several high-profile and costly litigations in the '90s, companies that actively market their polymers for medical applications typically have developed policies regarding restricted or permitted applications like ‘skin contact only’,’ max. 24 hours inside the body’ or ‘max. 29 days inside the body’.
“The restrictions may often not be related to the expected performance of the polymer in the target application, but rather reflect the corporate environment and legal department’s decisions. They can have much more to do with perceived risk exposure to litigation down the line”, explains Bastiansen.
“Our partner Lubrizol LifeSciences is one of the very few polymer suppliers who do not restrict the use of their TPUs to 30 day implants but instead have a disclaimer reminding that the choice of polymer is up to the device manufacturer. Medical device designers are free to select from a wide TPU portfolio the most suitable grades to be tested and considered for each specific application. On the other hand, if we have a customer who has very low volume of demands for a coloured material for a non-invasive device, we can offer a range of options advising MOQs of coloured resins direct from the producer, or assist in finding a long-term sustainable solution with our medical compounding partner IPC.”
For medical device manufacturers and OEMs, especially the specialized small and medium-sized businesses, it is very challenging to keep track of all the different and complex policies and disclaimers. “As a specialist medical-polymer distributor, VELOX see its role as being the critical bridge between our polymer principals and our customers, the device manufacturers, to make the right polymer choice process a safe, successful, sustainable and convenient one,” adds Bastiansen.
MDR and its impact for manufacturers
While polymer producers have determined their own individual set of characteristics to define what a medical grade is, medical device manufacturers have been theoretically free to choose any polymer, as long as they followed existing regulations, while carrying the risks involved with product liability. Many device manufacturers have relied on compliance with applicable standards such as USP Class VI and ISO 10993, with regard to biocompatibility when choosing the material for their application.
The new European Union Medical Device Regulation 2017/745 (MDR), which will be mandatory from 26th May 2020, places a strong emphasis on risk management and safety. It not only comprises new classification rules as well as extra surveillance and safety reports, but also reinforces the position of notified bodies, demanding that they “carry out unannounced on-site audits and to conduct physical or laboratory tests on devices to ensure continuous compliance by manufacturers after receipt of the original certification”.
“Especially for many small and medium-sized medical device manufacturers, the new, more demanding law may sound the death knell, as it will make the market entry for their products extremely difficult and expensive,” Bastiansen commented.
Still, when it comes to an industry-wide, standard definition for medical-grade polymer, the new MDR, like MDD before, remains silent.
First step towards binding definition of medical grades
However, things are moving in Germany. The Association of German Engineers, VDI, has implemented a committee for defining a standard for medical-grade polymers. A first draft was presented at the VDI symposium ‘Plastics in Medical Technology’, which took place on 10 and 11 April, 2018 in Friedrichshafen. The final guideline is to be available at the end of 2018.
“We are fully supportive of the VDI aim, and think that a standard definition would bring more reliability, stability and long-term commitment for all sides. This is what polymer manufacturers and medical device producers alike need,” said Bastiansen.
Change management and long-term commitment
In the meantime, specialised medical polymer producers have already taken the opportunity to create indispensable value for medical plastics processors and OEMs.
To understand the peculiarity, one has to recall that only up to 3% of the worldwide polymer production ends up in medical and healthcare applications. For many polymer suppliers that serve diverse high-volume industries like automotive, food, construction etc., it may make no economic sense to invest in a market with such small potential volumes, even though several of these ‘industrial grade’ resins have made their way into products that are considered as medical devices.
For medical device manufacturers, this holds several risks and challenges as they need to rely on long-term supply and predictability, whereas in the industrial polymer sector sudden product obsolescence or changes in the raw material production are common, without always informing the end customers.
“Polymer suppliers that develop and provide specialised polymers for medical applications have discovered a significant gap in this complicated situation to add value for the manufacturers,” highlighted Bastiansen.
“Suppliers like Repsol or Lubrizol LifeSciences that we have been cooperating with for many years have put transparent mechanisms into place to ease the process of change control for the OEMs and to also secure a long-term supply.”
Cristina Martinez from Velox’s partner Repsol, healthcare division, explains the challenge precisely: “The typical dynamic in chemical plants producing hundreds of thousands of tonnes such as we have for our PE, PP and EVA resins, is to strive for continuous improvement in efficiencies, quality, innovation and economics. By implication, things are always changing – new grades bring advantages and old grades become obsolete – which is great for our industrial customers but can be a nightmare for medical customers.
“The challenge in setting up our Repsol Healthcare portfolio has not been of a technical nature in developing innovative new grades. The much bigger task has been to understand the needs of medical and pharma companies and to put the necessary product stewardship in place across all the stakeholders within the organisation. This means production, purchasing, logistics, R&D as well as sales and marketing.
“So knowing your supplier and being sure that they know you and your application is the ideal scenario,” summed up Bastiansen. “They can give the right support, advise you and be there for the long term, which is crucial for success across the lifetime of the product. This is even more true within the context of the new MDR.”