ERC-RMB Leads ASTM Toronto Meeting for Development of Absorbable Metal Standards
May 6, 2014
Outcome / accomplishment: On May 6, 2014: The ASTM and ERC led a sub-workshop for Standardization Strategy for Absorbable Metals at 10th ASTM International Conference held in Toronto, CA. The objective was to have a basic review of the current state of absorbable metals evaluation and standardization and what content will be needed in new standards that are being developed with international collaboration. Dr. Yeoheung Yun and Dr. Aaron Barchowsky at ERC-RMB, along with Dr Byron Hayes at ASTM and W.L.Gore & Associates, opened the presentations and led discussions of needs in new degradation/corrosion and toxicity/biocompatibility testing standards. The meeting ERC-RMB team is closely involved in identifying needs in the testing standards and further leading standards development with ASTM and ISO.
Impact / benefits: This workshop was attended by ~25 experts on site and 10 on web-connections (invited persons only). The attendees ranged from academic and industrial researchers, to clinicians and FDA regulators actively engaged in absorbable materials research and development, as well as regulation from around the globe. This forum enriched the absorbable metals community through drawing on meaningful areas to develop testing standards with ASTM and eventually ISO. A definitive outcome was creation of subgroups responsible for reviewing and developing specific testing standards and reporting. Dr Yun will be involved in the group evaluating corrosion testing and Dr Barchowsky will be involved developing biocompatibility testing standards. ERC member, Dr Frank Witte, will be working with both groups.
Explanation / background: Interface of devices with their local in vivo environment is sophisticated, impacted by the surrounding environment such as 1) dynamic loads and 2) fluid flow (perfusion) complex environments induced changes to the material surface, such as pitting, hydrogen enbrittleness and stress induced fracture (different types of corrosion). Further testing standard procedures for biocompatibility and toxicity tests will allow these important new devices to move into commercially viable products. No standard is currently available for testing absorbable metals devices and existing standards for other absorbable materials or non-absorbable metals are not adequate to use for absorbable metal and metal device testing methods. This workshop discussed the need areas for standardization including: 1) Materials, 2) In Vitro-In Vivo correlation, 3) Biological evaluation, 4) In Vitro degradation testing, 5) degradation product fate, and 6) Bulk corrosion test.
Dr. Yeoheung Yun, Associate Professor of Bioengineering at North Carolina A&T state University and leader for the ERC-RMB’s studies towards standardization of degradation testing method gave a presentation titled: “In Vitro Degradation Testing Methods for Biodegradable Magnesium Alloys”. In his talk, Dr. Yun discussed the challenges faced in testing materials absorption, particularly in correlating in vitro test results with in-vivo performance. Confounding factors include local perfusion, exposure to proteins, mechanical stress, fluidic flow, and the impact of solutes on degradation product composition.
Dr. Aaron Barchowsky, Professor of Environmental and Occupational Health at the University of Pittsburgh and leader of the ERC-RMB Green Team for biocompatibility/toxicity testing, gave a presentation entitled: “Meeting the challenges of standardized biocompatibility/toxicity testing for implantable devices made from degradable metal alloys.” He discussed the challenges faced in generating alloy and device-specific testing procedures and consensus on standards for regulating biodegradable metal device safety. These challenges include all of those posed by materials testing in biological fluids and tissues, as well as application specific needs that include implantation site and systemic toxicity testing.
In addition to these presentations, ERC leadership and PIs had the opportunity to build and strengthen relationships with key industrial colleagues and members of ISO, ASTM and the FDA with the unifying objective of developing new standards that reduce the barriers for developing safe and clinically effective absorbable metal devices.