FDA-Approved Materials for Medical Devices

Quality is important in just about every industry, but when it comes to FDA-approved materials for medical devices, quality is a life-and-death consideration.

Low-quality or incompatible materials can cost lives and cause illnesses. That’s why the U.S. Food and Drug Administration (FDA) has stepped in to regulate which materials can be used in medical devices. One of the most common materials involved in these devices, for which the FDA has issued clear standards and regulations, is silicone.

So, which silicones are FDA-approved for use in medical devices? Which other standards govern whether and how these materials may be used? And what properties do these materials have? We explore all that and more in this blog post. Read on to learn more.

You can’t take risks on quality when you’re making medical devices. That’s why so many engineers and designers partner with Modus Advanced for their medical device projects. We promise premier quality for every medical device project. Contact us to learn more.

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About FDA CFR 177.2600

As you likely know, the FDA regulates foods, drugs, and medical devices. It’s a federal government agency, and many of its directives are encoded in the Code of Federal Regulations (CFR).

It’s in that lengthy tome that you will find CFR 177.2600, the statute that regulates the materials that can be used in medical devices intended for repeated use. To simplify what is kind of a long read, any silicone you intend to use in a medical device must comply with CFR 177.2600.

The regulation discusses the specific materials cleared for use in devices that are intended for medical use or that will touch food that will be consumed, including the properties of those approved materials.

While FDA CFR 177.2600 provides the regulatory framework for materials used in medical devices, it's crucial to understand that compliance with these regulations is just the first step in ensuring the safety and efficacy of medical materials. 

To further validate the biocompatibility and safety of these materials, additional testing standards have been developed. One of the most rigorous and widely recognized of these standards is USP Class VI testing.

About USP Class VI

USP material testing classes are broken into six groups of standards, with Class VI being the most stringent. This is the testing class you will need any silicone you use in a medical device to pass.

That’s because USP Class VI ensures that the tested material is biocompatible with use in humans, meaning it will not cause harm. That is determined in a few ways:

• Systemic injection: In this part of the USP Class VI testing, a test subject is injected with an extract derived from the material being tested and monitored for signs of toxicity.
• Intracutaneous testing: This portion of the testing monitors skin reactions to the extract from the material under testing.
• Implantation testing: This part of the testing looks for any reactions in the test subject’s tissue after being in constant contact with the material for several days.

As you can see, USP Class VI testing is rigorous — which is exactly what you need to ensure that all FDA-approved materials used in your medical devices are truly safe for use.

About RoHS Compliance

The Restriction of Hazardous Substances (RoHS) directive, implemented by the European Union, plays a crucial role in regulating the materials used in electrical and electronic equipment (EEE), including medical devices.

While initially focused on the EU market, RoHS compliance has become a global standard for quality and environmental responsibility. RoHS restricts the use of six hazardous substances in EEE: lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE).

The directive aims to reduce the environmental impact of electronic waste and protect human health from these potentially harmful substances.

For medical device manufacturers, RoHS compliance is not universally required for all materials, particularly silicones. However, adhering to RoHS standards is increasingly important for several reasons:

1. Global market access: Compliance ensures products can be sold in the EU and other regions adopting similar regulations.
2. Environmental responsibility: It demonstrates a commitment to reducing hazardous waste and environmental impact.
3. Quality assurance: RoHS-compliant materials often meet higher quality standards.
4. Future-proofing: As regulations evolve, RoHS compliance can prepare manufacturers for potential changes in other markets.

Even for products not intended for the EU market, considering RoHS compliance in material selection and design can enhance overall product quality and marketability. It's a proactive approach that aligns with global trends toward safer, more environmentally friendly medical devices.

Examples of FDA/USP VI Silicones

Some silicones are compliant with FDA CFR 177.2600, while others are compliant with USP Class VI or RoHS. But few are compliant with all three regulations. Those silicones that are compliant with this trio of guidelines are among the highest-quality materials available.

Here’s an example of such a silicone: the SSP-2390 Series of silicones. Specialty Silicone Products (SSP) is known for its high-quality silicones, and the SSP-2390 Series certainly exemplifies that attribute.

All silicones in the SSP-2390 Series are translucent silicone elastomers that comply with FDA CFR 177.2600, USP Class VI, and RoHS. They are heat-cured, platinum-catalyzed, and available in durometers that range from 10 to 80.

Platinum-cured silicones like these are cleaner and more pure than those cured with peroxide, making them ideal for use in medical devices. The other benefits of platinum curing include more robust physical properties and lower shrinkage.

FDA's Role in Medical Device Safety

The FDA's Center for Devices and Radiological Health (CDRH) is responsible for ensuring the safety and effectiveness of medical devices. This includes evaluating the materials used in medical devices to ensure they do not cause adverse reactions in the human body. The FDA's evaluation process includes a thorough review of the material composition, intended use, and specific properties of the device materials.

Biocompatibility and Risk Assessment

Medical device manufacturers must conduct extensive biocompatibility testing to demonstrate that the materials used in their devices are safe for use in or on the human body.

This involves assessing the potential for adverse biological responses, such as immunological responses or tissue changes, that could result from contact with the device materials. The FDA's biocompatibility guidance, based on the ISO 10993 series of standards, provides recommendations on the types of information that should be provided to support the safety of device materials.

Biocompatibility testing includes a range of evaluations:

1. Cytotoxicity: Determines if the material causes cell death or inhibits cell growth.
2. Sensitization: Assesses the potential for allergic reactions.
3. Irritation: Evaluates localized inflammation or irritation.
4. Systemic toxicity: Examines if the material releases harmful substances.
5. Genotoxicity: Evaluates potential genetic damage.
6. Implantation: Assesses local effects after implantation.
7. Hemocompatibility: Determines compatibility with blood.

The specific tests required depend on the device's nature, intended use, and duration of contact with the body. For instance, long-term implants require more extensive testing than short-term external devices.

Risk assessment is integral to biocompatibility evaluation. Manufacturers must consider factors such as chemical composition, manufacturing processes, sterilization methods, degradation products, potential leachables, interaction with other materials, and the duration and frequency of exposure. Patient-specific factors like age, gender, health status, and pre-existing conditions are also important. A risk-based approach helps identify potential hazards, estimate the likelihood and severity of harm, and implement measures to mitigate risks.

The FDA reviews biocompatibility data and risk assessments during the premarket submission process to ensure safety and effectiveness. Additional testing or clinical data may be requested for novel materials or applications. Biocompatibility and risk assessment are ongoing processes throughout a device's lifecycle. Manufacturers must monitor device performance post-market and report any adverse events to the FDA.

Thorough biocompatibility testing and risk assessments ensure the safety and effectiveness of medical devices, contributing to better patient outcomes and public health.

Premarket Approval and Postmarket Reviews

For high-risk medical devices, such as Class III devices, manufacturers must obtain premarket approval (PMA) from the FDA.

This involves submitting detailed information about the device, including its material composition, manufacturing processes, and clinical use. The FDA also undertakes extensive postmarket reviews to monitor the safety and effectiveness of medical devices after they have been approved and are in use.

Conveying Materials Information to Healthcare Providers and Patients

The FDA has recognized the importance of conveying materials information about medical devices to healthcare providers and patients.

This includes providing clear and accurate information about the materials used in medical devices, their potential risks, and any safety concerns. The FDA has published a discussion paper to solicit feedback on how materials information can be effectively communicated to stakeholders.

Navigating the complex regulatory landscape of the medical device industry requires expertise and experience. Medical device manufacturers must stay up-to-date with the latest FDA regulations and guidelines to ensure their products meet the required safety and quality standards.

Partnering with a manufacturer that has regulatory expertise can help ensure compliance and reduce the risk of delays or issues during the approval process.

Modus: High-Quality Materials and Manufacturing for Medical Devices

Even if you have the perfect FDA-approved materials picked out for your medical device, your project can fall completely flat if you pick the wrong manufacturing partner. Small, careless mistakes on the shop floor can lead to stalled projects or worse, faulty medical devices.

And you can’t have that.

Don’t partner with a manufacturer who puts profit or anything else ahead of quality.

At Modus, we put quality first in everything we do, from medical devices to aerospace and defense devices, because we want to work with customers like you — customers who value the kind of quality we offer.

Interested in learning more? We’re ready to tell you everything you need to know about working with us. All you have to do is reach out to our team. Give us a call at 925-960-8700 or contact us online today.