Medical-grade polymers: Your questions answered

Polymers have been used in the healthcare and medical industry for decades — from orthopaedic and surgical instruments to diagnostic equipment, drug-delivery systems, implants and vision aids. For obvious reasons, the industry is heavily regulated to ensure quality, efficacy and – most importantly – safety. With patients’ lives at stake, choosing the right polymer for a specific medical or pharmaceutical application can get complicated. So, let’s unpack exactly what’s meant by “medical-grade” polymers and how to choose one that fits your needs.

Actually, there’s no single, universally accepted definition of medical-grade polymers or plastics. In 2017, the Association of German Engineers (VDI) published their Guideline for Medical Grade Plastics as a reference for polymer producers and medical device manufacturers. It covers development, logistics, procurement and purchasing, while defining the requirements of polymers used in medical applications and giving guidance for raw material producers and manufacturers of medical devices. And, right now, a revision of the 2017 VDI Guideline is in progress.

“We’re fully supportive of VDI’s initiative,” says Jana Zietzling, Head of Product Management Medical at IMCD. “Highlighting consistency in formulation, quality, biocompatibility and supply security brings more reliability, stability and long-term commitment for all sides.”

Despite these advances in Germany, the definition of a “medical-grade” polymer is yet to be agreed internationally.

Not surprisingly, medical device development is a long and complex process with strict compliance regulations, long-term tests, quality checks and certifications. But medical-grade polymers are a bit of a grey area. One reason is that a very small percentage of polymers actually end up in medical and healthcare applications. The vast majority go to high-volume industries like automotive, food packaging and construction. Also, while polymer suppliers have one set of rules, the medical industry has another.

In 2010, the so-called “PIP scandal” revealed that a French breast implant manufacturer (PIP) was using industrial, not surgical-grade, silicone. High rupture rates were reported with far-reaching financial, judicial and personal consequences for PIP, their suppliers, notified bodies and – most importantly – the patients affected. Once again, it exposed the extent of unresolved questions and uncertainties on all sides.

In the 1990s, many polymer suppliers withdrew from the medical market as a reaction to similar scandals. To stop the US market drying up, Congress passed the Biomaterials Access Assurance Act of 1998. It stipulates that raw material suppliers are not liable for product failures as long as they “meet applicable contractual requirements or specifications”. Since then, medical device manufacturers have invested heavily to ensure products comply with regulatory requirements and are safe for the intended application.

In Europe, many device manufacturers have relied on compliance with applicable standards, such as USP Class VI and ISO 10993 with regard to biocompatibility. The EU Medical Device Regulation 2017/745 (MDR) came into force in May 2021. It places strong emphasis on risk management and safety. Compared with previous guidelines, the MDR represents an expansion of product scope, more stringent documentation requirements, new classification rules, extra surveillance and safety reports.

As a medical device manufacturer or original equipment manufacturer (OEM), all this can be a lot to navigate, especially for small- and mid-sized businesses. But help is at hand. Medical polymer producers have already created value for medical plastics processors and OEMs. As a distributor of specialist medical polymers, IMCD is a critical bridge between you (device manufacturers) and our suppliers (polymer principals). We’re here to make the right polymer choice a safe, successful, sustainable and convenient process.

One consideration is the length of time a medical device will be in contact with the patient’s body. To date, there are few polymer producers that allow their materials to be used for implants that remain in the body more than 30 days. Following several high-profile court cases in the 1990s, companies that actively market their polymers for medical applications often end up developing their own policies on permitted applications. These rules may be less driven by expected performance and more related to fear of litigation. As such, they can be complicated. While one polymer might be permitted inside the body for less than 24 hours, another might be allowed for up to 29 days. Some polymers are restricted to “skin contact only” while others stipulate no direct contact with fluids entering the bloodstream.

Once you’ve carefully chosen and tested a material, you need to rely on long-term supply and predictability. Sudden shortages or changes in raw-material production are common in the industrial polymer sector. It means repeating the whole complicated and expensive gauntlet of tests, qualification and certification again – a process that can take years to complete. IMCD’s partners for medical-grade polymers have processes in place to ensure the best possible transition if changes need to be made. Agreements are put in place that define all the details, for example, advance notification requirements, whether a final-buy option is possible, and so on.