Bioresorbable Polymers for Medical Devices—A (Still) Emerging Field

MD&M West 2012 Event Coverage

Richard Meyst, president of Fallbrook Engineering Inc. (Escondido, CA), along with Steve Coulter, senior research associate, will present “Bioresorbable Polymers for Medical Devices—A (Still) Emerging Field” at the MD&M West conference program on Monday, February 13. Fallbrook Engineering is a design and consulting house focused on medical device design and development.

MPMN: What topics will you cover in your presentation?

Meyst: There are two main areas we are going to cover. The first area is how the selection of bioresorbable materials must conform to design controls, and a key part of that is properly specifying your requirements. Second, we want to convey a recent experience in which we found very limited options for commercial bioresorbable polymer sources.

MPMN: How does working with bioresorbable polymers differ from working with traditional materials?

Meyst: By their very nature, these materials are very sensitive to degradation. You need to consider every environment that the material is in from incoming receiving to sterilization, shipping, and storage. Additionally, these materials call for much more precise processing-method controls; designing “controlled change” into a product is no simple task. Another big difference is the raw material cost. These materials are usually very expensive compared with comparable polymers, such as nondegradable polyesters. As a result, you need to employ high-yield, low-waste molding technology. There are a limited number of molders that fully understand how to properly process bioresorbable polymers in order to achieve the desired result.

MPMN: What is the most common mistake made by medical device manufacturers when designing with bioresorbable materials?

Meyst: The thing that really stands out is trying to succeed without adequate process control, which includes considerations such as water content, temperature excursions, etc. On finished parts, OEMs need to take a close look at the effects of sterilization, the impact of residuals, and the overall effect of sterilization and storage on functional, mechanical, and chemical properties. They also need to know how long the material actually lasts. For example, the material may lose its strength in a year but may persist at the site for another year or more. Also, there’s a huge difference between surface erosion and bulk erosion for implantable, resorbable polymers. Companies need to look at how the loss of strength tracks with the loss of weight. And if used for drug release, how does the nature of erosion affect dosing?

MPMN: What’s next for bioresorbable materials in medical applications?

Meyst: We would like to see more polymers become available. We have found that materials that were near commercialization in the late 1990s are still not available. As a commercial process, this is a deadly spiral: If more materials do not become available, there won’t be as many potential uses and applications. With less use of the material, costs remain high because of poor demand, making it still less attractive for a designer to look for new bioresorbable material applications.

MPMN: What do you hope attendees will take away from this presentation?

Meyst: Because bioresorbable polymers have been well known and well characterized for decades, we thought that solving a commercialization issue would be easy. There should have been multiple material options and multiple supply sources available. Neither of these assumptions was true at all. If you are looking at medical product designs that require these materials, pay attention to the details. You should likely allow more money and time for development than you initially estimated.

For more information on the 2012 MD&M West Conference, visit www.mdmwestconference.com.