Medical Device biocompatibility, once considered just a “box-checking” activity, continues to become more complex. This was the focus of a talk at the 2012 American College of Toxicology Annual Meeting entitled “The Unique World of Safety and Toxicology Testing of Medical Devices.”
Drug Toxicology Versus Device Toxicology
Drug safety testing focuses on dose responses in vivo and in vitro, whereas device safety testing focuses on device failure and the toxicology of the materials making up the device. Although even the most complex device and most involved biocompatibility testing program doesn’t come close to the requirements for a new chemical entity, the toxicology of the materials still does need to be adequately addressed.
Risk assessment for medical devices is based on the chemical nature and known toxicity of a device’s constituent materials, the prior use of the materials and any records of their use, and the biological safety data generated by in vivo and in vitro testing.
The Changing Nature of Biocompatibility Testing
Historically, biocompatibility testing has been an exercise in determining the type of device and testing required according to ISO 10993, and then performing only that specific testing. However, since each device is unique, simply conducting the recommended biocompatibility studies may not be sufficient to allow for an adequate scientific and regulatory review of the device.
The choice of animal species may be affected by the type of device – for instance, artificial joint replacements may be best evaluated in certain strains of sheep.
Finally, biocompatibility testing should always be conducted according to Good Laboratory Practices (GLP). There once was some question about this, but the most recent FDA draft guidance for industry on 510(k) submissions made clear that GLP testing is a requirement.
It is important to be aware that as the regulatory environment changes, biocompatibility testing may continue to become more involved, and each device may require a testing program very specific to it. A lab with an established history of testing, or a consultant with device toxicology experience may be able to help with putting together an appropriate testing program.
Pacific BioLabs performs many types of medical device studies, including biocompatibility testing.