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ASTM International will host the Workshop on the Characterization of Hydrogel Medical Products on May 6, 2025, in Toronto, Canada, during the spring meeting of the ASTM Committee F04 on Medical and Surgical Materials and Devices. This event brings together leading experts to discuss best practices, emerging analytical techniques, and the urgent need for standardized testing methods for hydrogels used in medical devices.

Workshop Focus and Objectives

Hydrogels are increasingly vital in medical applications, from regenerative medicine to implantable devices, due to their unique properties as water-swollen, three-dimensional polymer networks. However, the lack of standardized characterization protocols presents challenges for manufacturers, regulators, and researchers. The workshop aims to:

• Review current analytical techniques for hydrogel characterization, including assessments of chemistry, morphology, mechanical properties, and in-use performance.

• Identify critical gaps in existing ASTM standards and discuss the need for new or improved test methods, particularly those relevant to both implantable and non-implantable hydrogel medical products.
  
  
• Foster collaboration among engineers, chemists, scientists, regulators, and industry stakeholders to advance the field and improve product safety and efficacy.

Who Should Attend

This workshop is designed for professionals involved in the development, testing, and regulation of hydrogel-based medical products, including:

• Medical device manufacturers

• Testing laboratories

• Regulatory agencies

• Pharmaceutical companies utilizing hydrogel technologies

Interactive Discussion and Next Steps

Attendees are encouraged to participate in an open discussion at the conclusion of the workshop to help shape the future of hydrogel test standardization. This collaborative session will be instrumental in determining priorities for new ASTM standards and identifying opportunities for further research and interlaboratory studies

Workshop Co-Chairs

• Stephen Spiegelberg, Cambridge Polymer Group

• Jon Moseley (Retired)

Featured Speakers and Presentations

Join the Conversation

Be part of the effort to shape the future of hydrogel medical product standards. Your expertise and input are vital to ensuring the safe and effective use of these soft materials in healthcare. For full event details and registration, visit the ASTM Workshop on the Characterization of Hydrogel Medical Products information page.

Microplastics have become a pressing topic in environmental and health discussions, with increasing attention from the media and scientific community. These tiny plastic particles, typically defined as ranging in size from 1 micrometer to 5 millimeters, can be composed of various types of polymers and are now being detected in an array of consumer products. A recent study by Huang et al. (2025)[1] examined the presence of microplastics in intravenous (IV) infusion bags, a common component of medical treatment.

What Are IV Infusion Bags?

IV infusion bags are flexible containers designed to deliver aqueous solutions, such as drugs, electrolytes, or saline, directly into a patient's bloodstream. Given their direct interaction with the body, the potential presence of microplastics in these containers may be of concern.

Key Findings from Huang et al.'s Study

Huang's study focuses of two brands of saline IV bags made from polypropylene. The contents of these bags were filtered, and the researchers employed Raman spectroscopy, scanning electron microscopy (SEM), and optical microscopy to identify and quantify the particles in the filtrate. The Raman spectroscopy confirmed that the particles were polypropylene. Particle counts revealed concentrations between 7020-7900 particles per liter of saline, with the majority (68%) measuring between 1-10 micrometers, and an overall size range of 1-62 micrometers.

The study did not speculate on how these microplastics entered the IV bags.

Health Implications

The authors note that microplastics have previously been discovered in human blood and adjacent organs, including the lungs, liver, kidneys, and spleen. Scientists at Cambridge Polymer Group are actively engaged in identifying and quantifying microplastics in products and tissues and in a recent study, we have detected microplastics in multiple lung tissue samples. The health implications of these microplastics remain uncertain at this time.

Regulatory Standards for Particulates

According to USP Particulate Matter in Injections, the limits for particles exceeding 10 micrometers should not surpass 12,000/L and 2,000/L for particles greater than 25 micrometers in containers holding more than 100 ml of solution. For containers with less than 100 ml, the limits are set at 3,000 particles (>10 micrometers) and 300 particles (>25 micrometers) per container. While the concentrations of microplastics found in Huang's study fall within these regulatory limits for larger particles (>10 micrometers), the sheer number of smaller particles raises questions about whether current standards adequately address this emerging issue.

What’s Next?

The detection of microplastics in IV infusion bags highlights a critical gap in our understanding of their potential health impacts. Further research is needed to explore:

1. How microplastics enter medical products during manufacturing or storage.
2. The long-term effects of introducing microplastics into the human body through medical treatments.
3. Whether existing regulatory standards should be updated to account for smaller particles.

As scientists continue to investigate this issue, healthcare providers and manufacturers must remain vigilant about minimizing contamination risks. In parallel, regulatory bodies may need to revisit particulate limits to ensure patient safety in light of emerging evidence on microplastics.

By shedding light on studies like Huang et al.'s, we can better understand and address this growing concern—ensuring that medical products meet the highest standards of safety and efficacy.

Companies regularly rely on third-party laboratory testing data to support regulatory medical device and pharmaceutical submissions, particularly when lacking in-house expertise or facilities. The credibility of these third party laboratories is crucial to regulatory success, but recent actions by the FDA highlight the risks associated with unvetted or noncompliant third party data.

Escalating FDA Scrutiny on Data Integrity

The FDA recently published warning letters to laboratories in China and India with concerns about fraudulent or unreliable testing data from these laboratories. One warning letter to a Chinese laboratory[1] concerned data from cytotoxicity and sensitization studies conducted on different dates with nearly identical results, raising suspicion that the data was not genuine. A series of letters released to an Indian laboratory in 2024 and 2025 notified pharmaceutical companies that any in vitro studies conducted by this laboratory for new drug applications and abbreviated new drug applications must be repeated at different study sites that do not have data integrity concerns.[2]

These warning letters reinforce a memo released from the FDA in February, 2024, warning medical device manufacturers to carefully examine data from third party laboratories to ensure the data is reliable.[3]

“The FDA has noted an increase in unreliable testing data generated by third-party testing facilities on behalf of device manufacturers and sponsors. This has resulted in the FDA being unable to reach a substantial equivalence determination or otherwise authorize marketing for medical devices whose submissions rely on such data.” — FDA Notification, March 2025[4]

Consequences for Manufacturers and Patients

This surge in data integrity issues has led the FDA to reject entire submissions, preventing the agency from reaching substantial equivalence determinations or authorizing marketing for affected medical devices. When the FDA cannot rely on submitted data, not only are sponsors forced to repeat costly studies, but patient access to new devices is also delayed, and supply chains may be disrupted.

Cambridge Polymer Group’s Commitment to Data Integrity

At Cambridge Polymer Group, we recognize the regulatory and reputational risks associated with unreliable data. Our protocols follow published standards, with calibrated, verified equipment, rigorous data checks, and comprehensive review processes. All raw and processed data, as well as equipment information, are available for client and regulatory inspection, ensuring transparency and readiness for regulatory review.

Conclusion

The FDA’s ongoing focus on data integrity makes it clear: the cost of unreliable third-party testing is high, with potential for regulatory setbacks, financial loss, and reputational harm. Selecting a transparent, compliant, and reliable laboratory partner is essential for successful regulatory submissions and for maintaining patient and market trust.

Traditional headlamps (worn above) are cumbersome and don't accommodate face shields.

A groundbreaking surgical task light has been introduced by MezLight in collaboration with Syensqo[1], demonstrating a thoughtful approach to product design by considering key factors such as:

• Customer needs
• Sustainability concerns
• Environmental durability
• Material suitability

Addressing Customer Needs: Enhanced Usability and Safety

Traditional surgical task lights are typically worn as headlamps by surgeons (see image above), which can become uncomfortable and cumbersome during extended procedures. The new MezLight task features an adjustable arm allowing for precise positioning and eliminating the burden of a headlamp. This design also accommodates the use of face shields, thereby prioritizing both usability and safety for surgeons.

Sustainability: Built for Repeated Use

In terms of sustainability, the task light has been engineered to withstand repeated cleaning and sterilization through steam sterilization using an autoclave, successfully enduring over 100 autoclave cycles. This capability ensures a long lifetime of repeated cleaning cycles for the product. As a result, the light has been designed to be robust enough for mechanical positioning and adjustment during surgical procedures over many repeated uses.

Material Selection: Meeting Rigorous Medical Standards

To meet the stringent requirements for mechanical performance and sterilization, the design team chose Radel®, a polyphenylsulfone (PPSU) supplied by Syensqo. This material was selected based on its exceptional properties:

• High heat deflection temperature of 207°C, ensuring stability under autoclave conditions and preventing deformation from the LED heat source.
• Good hydrolytic stability, enabling it to withstand repeated exposure to high-temperature steam without degradation
• Impact strength comparable to other durable plastics such as polycarbonate, ensuring mechanical integrity during use.

Radel® has also been historically used in surgical instrument handles and trays, proving its ability to endure multiple sterilization cycles.

A Model of Comprehensive Design

This surgical task light exemplifies the comprehensive considerations involved in material selection for medical products, while ensuring the fulfillment of customer needs. By addressing the unique challenges faced in surgical environments, this product not only meets the practical demands of healthcare professionals but also aligns with sustainability goals in medical device manufacturing.

Every year on March 17th, we commemorate the invention of the rubber band, patented by Stephen Perry in 1845. This innovation followed Charles Goodyear's groundbreaking discovery in 1838 that adding sulfur to polyisoprene creates crosslinks, significantly enhancing its elastic properties. This breakthrough led to the development of rubber tires.

Composition of Rubber Bands

Rubber bands are traditionally made from polyisoprene, a polymeric elastomer derived from either the latex sap of rubber trees or petroleum products. They can also be made from ethylene propylene diene (EPDM) rubber and silicone. Polyisoprene rubber bands are prone to degradation, especially when exposed to sunlight, which causes them to become brittle over time. In contrast, silicone and EPDM rubber bands are more resistant to degradation.

Elastic Properties

Rubber bands are almost purely elastic, meaning they return to their original dimensions after being stretched and released without any permanent deformation. This elasticity is due to the crosslinks in the rubber that connect adjacent long polymer chains, forming a three-dimensional network. This process can be repeated multiple times without causing permanent deformation.

Thermal Dynamic Principles

In the mid-1800s, Lord Kelvin developed the theory of thermodynamics using rubber samples as examples of entropy principles. James Joule confirmed Kelvin's theory with experiments showing that rubber samples increase in temperature when stretched. Two key principles underlie the thermodynamics of rubber bands:

1. Internal Energy Independence. The internal energy $U$ of a rubber band is independent of its length L0L0, expressed as U=cL0TU=cL0T, where $T$ is the temperature and $c$ is a constant
2. Linear Tension Increases. The tension $\sigma$ of a rubber band increases linearly with its length, given by $\sigma =bT\Delta L$, where $b$ is another constant and $\Delta L$ is the change in length.

Kelvin described the thermodynamics of stretching a rubber band using the Helmholtz free energy ($A$) expression: $A=U-TS$, where $S$ is the entropy of the system. $A$ represents the total energy available to do work. The internal energy $U$ includes potential and kinetic energy, expressed as $U=Q-W$, where $Q$ is heat added to the system and $W$ is work done by the system. Heat transfer can be written as $dQ=TdS$, and work done on the rubber band as $dW=\sigma dL$. Rearranging these expressions yields $dF=\sigma dL-SdT$, where $dF$ is the change in free energy, $dL$ is the change in length, and $dT$ is the change in temperature.

The temperature change in a rubber band is given by $dT=dL(\sigma /S)-dF(1/S)$. When a rubber band is stretched ($dL$ positive), its temperature rises. Conversely, when it relaxes ($dL$ negative), its temperature falls. At points where the rubber band is held at a fixed distance, heat either dissipates into the environment or the environment warms the cooled rubber band.

Molecular Alignment and Entropy

On a polymeric level, stretching a rubber band aligns and orders its molecules, decreasing entropy. When the rubber band relaxes, the polymer chains also relax, increasing entropy again.

Experimenting with Thermodynamics

You can easily demonstrate these principles by lightly placing a rubber band against your lips, which are sensitive to temperature, and moderately stretching it. You should feel a temperature rise. When the rubber band is relaxed, a cooling sensation should be noticeable. This simple experiment illustrates the effects of microscopic molecular motion. 

Remember to wear safety glasses when conducting this test.

Over the February 15-16, 2025 weekend, the new U.S. administration laid off a substantial number of FDA reviewers from the Center for Device and Radiological Health (CDRH), the branch that reviews the safety and efficacy of new medical devices, including hip and knee implants, cardiovascular and respiratory devices, ophthalmological treatments, wound care, and thousands of other types of medical devices.

MDUFA Commitments and Funding Concerns

The Medical Device User Fee Amendments (MDUFA) program, funded by fees from medical device companies, was established to ensure timely and thorough reviews of new medical devices. Many of the laid-off employees were hired specifically to fulfill MDUFA commitments. This raises questions about:

• Resource allocation: How will the FDA maintain its review capacity with reduced staff?
• Financial implications: Given that user fees largely cover reviewer costs, the rationale behind these layoffs in terms of government spending remains unclear.

Potential Consequences of FDA Layoffs

Review Process Challenges

The reduction in the reviewer workforce is likely to have several immediate effects:

• Delayed reviews: Fewer reviewers may lead to longer wait times for device approvals.
• Compromised quality: The scientific rigor of reviews may be affected due to the increased workload on remaining staff.

Expertise Gaps

The layoffs have created critical gaps in specialized knowledge:

• AI expertise shortage: The layoffs also included reviewers with specialization in artificial intelligence. Given the trend towards incorporating AI into medical data interpretation and hardware responses, reviewers with this expertise are particularly needed at this time.
• Respiratory device oversight: The dismissal of half the subject matter experts in respiratory devices is alarming, especially given recent issues in this area.

Industry and Patient Impact

The FDA's ability to advance regulatory science and facilitate medical device innovation may be compromised, potentially affecting the United States' leadership position in the field.

The loss of experienced reviewers is likely to have far-reaching consequences:

• Medical device companies: May face longer approval timelines and increased uncertainty.
• Healthcare providers: Could experience delays in accessing new medical technologies.
• Patients: May face potential safety risks and delayed access to innovative treatments.

As the situation continues to evolve, medical device companies, healthcare providers, and patients should stay informed about potential impacts on device approvals and safety monitoring. We will continue to monitor the situation and advise our clients as we can.