On March 2, 1999, the U.S. Food and Drug Administration released a guidance document entitled Guidance for the Preparation of a Premarket Notification Application for a Surgical Mesh. Now in 2018, nearly 20 years later, it is still easy to become overwhelmed with everything required to prepare a new device for submission to the FDA. Guidance documents such as this one provide recommendations for the starting points of testing new devices and help alleviate some of the guesswork around what is required and what isn’t. Fortunately, partnering with a company like Poly-Med, with over 25 years of experience in bioresorbable materials and textiles, can help further navigate these waters.

This particular guidance document covers submission guidelines for surgical meshes in a wide variety of applications where a mesh product would be used to reinforce weakened soft tissue. These include area applications in abdominal wall repair (hernia repair), suture line/staple line reinforcement, muscle flap reinforcement, gastric banding, breast reconstruction, pelvic organ prolapse, and many more. For many of these applications, the current market trend is moving toward bioresorbable solutions, providing mechanical support throughout the healing process without permanent synthetic materials in the body. Poly-Med is the leader in bioresorbable textiles and has developed bioresorbable mesh products on the market for a wide variety of applications.

The FDA’s primary interest in any device review can usually be summarized in two words: safety and efficacy. Not surprisingly at all, the guidance document first focuses on the product being safe for human use. Likewise, this is usually a best first-step to consider in product development as future product development will all hinge on the materials as being safe for implantation. With this in this focus, the FDA requires the submission to include description of all material components in the device. This includes at minimum the sources/supplier and purity. To satisfy this requirement, material suppliers can provide reference to device master files (MAF), Certificate of Analysis (CoA), and Safety Data Sheets (SDS) with materials, all of which are noted to help simplify the review process. When considering the materials, special attention should be paid to any materials, reagents, or processing aids which are considered to be potentially cytotoxic, carcinogenic, or immunogenic. Additional testing may be required for any of these materials which are used to air in processing and may remain as residuals in the final material.

The next step in safety of an implantable device is consideration of sterilization. Applications are suggested to specify the method, validations, sterility assurance level (SAL, recommended SAL of 10-6), method for monitoring sterility, and packaging used to maintain sterility. Poly-Med uses several trusted partners with experience in sterilization to coordinate offering these services to our clients. Dependent on the type of material used and the desired processing plan, bioresorbable meshes can be sterilized using irradiation, ethylene oxide, or new emerging technologies such as nitrogen dioxide1.

While many of our materials are used in devices on the market and have proven biocompatibility, it is recommended that biocompatibility testing be conducted on final manufactured, sterilized, and packaged devices, as all can influence the final reaction in the body. While some provisions are allowed for products using the exact same material specifications as another similar device on the market, the guidance generally recommends that applications include testing in accordance to ISO-10993 for Cytotoxicity, Sensitization, Irritation or Intracutaneous Reactivity, Systemic Toxicity (acute), Genotoxicity, Implantation with histology of the surrounding tissue, Hemolysis, and Pyrogenicity. Given that most bioresorbable materials will leave some mass within the body for greater than 30 days, the FDA further recommends testing for Subchronic Toxicity and Chronic Toxicity. These tests should generally be conducted according to relevant USP Class VI and ASTM standards.

When using bioresorbable materials, part of the efficacy claim of a surgical mesh is its ability to degrade over time. In alignment with this guidance, Poly-Med often performs degradation studies for each device developed, being sure to take into account material selection, processing methods, as well as sterilization. Poly-Med is fully capable of conducting in-house in vitro degradation studies in both real and accelerated environments. Accelerated time points are used to quickly identify appropriate time points for a real time study and then evaluate device functionality and specifications at pre-determined time points. For surgical mesh devices, common strength loss tests are dependent on the application, and often include tensile strength, burst strength, suture pull-out strength, and tear resistance.

Though expiration dating is required for all surgical meshes, the need is especially apparent with bioresorbable materials. Many of these materials degrade with exposure to moisture, light, and/or heat, so packaging and sterilization methods can play a critical role in the ultimate shelf-life of the product. This guidance allows for expiration dating to be continuously updated over time without the need for a new 510k submission under the scope of Good Manufacturing Practice (GMP). This allows products to quickly enter the market and then slowly increase the expiration dates of new production as the real-time stability study continues.

If you are interested in developing a bioresorbable surgical mesh and want a partner with experience, Contact us for more information!

Andrew Hargett, M.S.

1 Lambert, B., et al. (2011). AAPS PharmSciTech, 12(4), pp. 1116-1126. doi: 10.1208/s12249-011-9644-8
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3225553/

If you’ve ever woken up late for an important job interview or meeting, you’ve probably thrown on some clothes and looked in the mirror with horror at all of the wrinkles staring back at you. While ironing clothes is certainly not one of my favorite chores, something about the heat and steam can totally change the outfit’s look. In medical textiles, this process of heat setting is equally important…and not just to look good in the operating room!

At Poly-Med, Inc., we synthesize very unique polymers for extrusion into fibers/yarns and ultimately for knitting into specialized medical textiles. Though the material coming off of the knitting machine looks somewhat finished, the process to manufacture a useful product is often far from done. One such post-processing technique we use is known as heat setting. Though our materials are medical grade and bioresorbable, the core chemistry at work with heat setting our advanced textiles is the same as with ironing common clothing materials.

The long, polymeric chains in both synthetic clothing and our bioresorbable polymers are able to “stick” together to produce fibers by means of intermolecular forces, namely hydrogen bonds. When exposed to moisture, pressure, and/or temperature, these intermolecular bonds can break, shift, and realign to produce unwanted creases. Even without the externally added forces, internal stresses are introduced throughout processing, such as from the twisting of yarn during spinning or the bending of the yarn during knitting to produce the pattern.

To work around this and remove the internal stresses, the fabric can be heated above the Glass Transition Temperature (Tg), where amorphous regions of the polymer can easily slide around. This temperature is below the Melting Temperature (Tm) and thus does not result in a phase change of the fabric, but merely provides enough energy to break down the intermolecular forces in the amorphous region which previously formed into now undesirable positions. As the material cools back down, the intermolecular forces can stabilize into stress-free conditions for whatever configuration the fabric is currently held in. For clothing with a heavy iron on top of it, the result tends to ‘press’ out the wrinkles and flatten the fabric between the flat ironing board and iron.

It is here, in the actual processing methods, that differences arise for our unique materials. In clothing, a particularly pesky wrinkle can be conquered with the addition of steam and a little elbow grease. The addition of water easily penetrates the amorphous regions of the fibers and acts as a plasticizer or lubricant between the polymeric chains, effectively reducing the material’s Tg to allow the amorphous regions more freedom to move. When the material hydrolytically degrades, as with our bioresorbable polymers, the addition of steam isn’t such a great idea. We instead use dry heat, forced air, and even vacuum chambers to apply heat to the fabric and still avoid degradation or strength loss. Heat Setting by these means further allows us to use custom fixtures and presses to hold the fabric in place as it cools, producing flat as well as 3D fabric forms. While this does make the medical textiles look great, the process often improves function as well, improving handle-ability for downstream processing and end-use, allowing the construct to conform to a unique shape, providing dimensional stability, and also increasing temperature resistance.

Though bioresorbable polymers pose a few unique challenges for heat setting, Poly-Med is very experienced in unique solutions for both small and large scale projects. If you are interested in post-processing of medical textiles or you are working on a medical device and are interested in learning more about bioresorbable polymers, Contact us at sales@poly-med.com to learn how we can advance your idea.

Andrew Hargett, M.S.

Poly-Med, Inc., one of the first biotech companies creating bioresorbable polymers for use in medical and pharmaceutical devices is celebrating an important milestone in their history this year; 25 Years of Innovation in South Carolina.

Poly-Med, Inc. was founded by Dr. Shalaby W. Shalaby, considered one of the forefathers of the bioresorbable polymer industry. He was one of the lead inventors for several bioresorbable products that we still use today, notably, the Vicryl®suture.

Dr. Shalaby came to South Carolina in 1990 to teach and conduct research at Clemson University. He launched Poly-Med, Inc. in 1993, as a means to translate his research into medical therapies, as well as to mentor, teach, and sponsor former and current students’ continuing education.

Today, under Dave Shalaby, Dr. Shalaby’s son, Poly-Med, Inc. creates first-in-class transformative bioresorbable medical devices and pharmaceutical products, which have improved millions of patient’s lives. Poly-Med, a once small startup, has been built into a sustainable technology company that attracts and retains the best engineers, scientists, and collaborators from around the world. Dr. Shalaby had a vision when he started Poly-Med, Inc. in South Carolina. He enabled many employees to gain experience, share ideas, in a collaborative effort, and help lay the foundation for the next generation of bioresorbable polymers and medical devices. Under Dave Shalaby’s, leadership, Poly-Med, Inc. has been taken to the next level, and continues to support and improve on the things his father held dear, the application of research,  education, and fostering innovation..

“The work we do at Poly-Med is meaningful in so many ways. As a researcher, we have a chance to work with the most advanced materials and technologies. As a product developer, we work to create first-of-their-kind products to help solve unmet needs. As a collaborator, we get to work with people and companies around the world in a way that we could not have ever imagined. This is how we continue to grow the history of Poly-Med – taking chances, identifying (sometimes hidden) talent, and building new ideas into a meaningful reality.” – Scott Taylor, CTO.

Through continued improvement in personal and professional growth, Poly-Med, Inc. employees are ready and excited to further advance and innovate in the medtech and biotech industries and continue making strides to improve patient quality of life through the devices they manufacture.