A new trend: No false equivalence

Xi Peng, technical consultant, polymers, Lucideon, discusses some of the current trends in the sector and provides an application overview of some of the techniques.

Advances in technology ensure that testing and regulatory support for a wide range of devices and materials across the medical industry are constantly innovating. 

Polymers are used extensively in the manufacture of medical devices and must meet demanding industrial requirements. 

With devices being generally complex in geometry, material and chemistry, the work plans often need to be thought about carefully to ensure the tests performed give the truest evaluation of medical devices in use. 

Companies such as Lucideon work to ISO, ASTM, and FDA standards, as well as novel methodologies with rationale when the standards are not adequate. 

One of the most popular methods requested by medical device manufacturers is equivalence testing.  

To undertake work in this area, a range of techniques and methods are utilised. These can include: 

FTIR (Fourier Transform Infrared Spectroscopy) provides detailed information on the chemical structures within compounds. FTIR depends upon the absorption of infra-red radiation arising from the vibrational and rotational characteristics of dipolar chemical compounds and is a powerful technique for polymer identification. 

DSC (Differential Scanning Calorimetry) is a thermoanalytical technique used to study the thermal transitions of a polymer. DSC yields a plot of temperature versus heat flow and provides information on thermal characteristics, thermal history, and curing performance of polymer samples.  

TGA (Thermo-gravimetric Analysis) is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes, thus providing information on the bulk composition and thermal stability of polymers.   

GPC (Gel Permeation Chromatography) determines the molecular weight and molecular weight distribution of polymers which are some of the most important characteristics of thermoplastic polymers; they have great impact on mechanical properties and processability.  

SEM/EDX (Scanning Electron Microscopy/Energy Dispersive Analysis) provides detailed high-resolution images across the surface sample size measurement and can also provide elemental identification and quantitative compositional information. 

It is important for clients to receive analysis and interpretation of test results, and not just the numbers. 

Analytical interpretation and rationale support make equivalence studies more robust when they are able to clearly demonstrate why a method is chosen and show what the results mean for the materials and the manufactured devices. 

Reasoning behind equivalence testing  

There is a growing trend from medical device manufacturers for equivalence testing. The reasons behind this are varied and include the desire to introduce new innovations or change suppliers. 

Investigations as part of competitor analysis, which might be needed to help a medical device manufacturer retain their position in the marketplace, also draw on equivalence testing. 

Another driver is a legacy from the pandemic; the material shortages and supply chain staffing shortages we saw during COVID-19 are still lingering. As a result, new materials are being considered and equivalence testing needs to be implemented to ensure alternatives offer the equivalent performance attributes. 

There is also enhanced pressure across the industry to remove certain raw materials, and/or ingredients to meet new safety concerns and regulations. 

Finally, ever changing market pressures to continually add functionality to existing products, in areas such as antimicrobial and antibacterial resistance, also need to be addressed.  

As a result of all these factors and more, medical device manufacturers might not only look at equivalence and analytical comparison, but also at alternative polymers and other materials. 

This is where polymer consultancy services can come into play. Addressing factors relevant to the medical device sector, they address the key areas of materials selection and characterisation such as biocompatibility of new choices.  

The services also cover specific details, including how to process, clean, and sterilise the new materials. 

Advanced materials are constantly evolving, improving, and transforming the medical device industry. For manufacturers, the options are there to test and challenge how they can be implemented into medical devices for long-term gains.