Several fundamental factors come into play when selecting the correct bioabsorbable material for a medical device that needs to be absorbed by the body over time. These devices eliminate the need for surgical removal and are often used for tissue support, drug delivery, and structural scaffolding. Ensuring biocompatibility and product performance are critical when considering the final material selection and manufacturing process. These materials slowly break down into byproducts of water and carbon dioxide, which reduce the risk for infection by foreign materials in the body for a long duration of time. The duration and strength integrity of the resulting device makes material selection especially important. Therefore, an understanding of the medical device application, mechanical properties, biocompatibility, and the hygroscopic degradation rate. Processing considerations are paramount at the material selection juncture. The right material mated to the wrong processes will result in a device failure.
Bioabsorbables in the Regulatory landscape
The regulatory requirements vary depending on the product and the country or region that the device will go-to-market in.
In general, the United States regulatory FDA landscape can vary depending on its classification. A 510(k) clearance or Premarket Approval (PMA) are also necessary. Biocompatibility testing is used to make sure no adverse reactions happen when the bioabsorbable medical device encounters biological tissue. And lastly, adhering to proper sterilizations and packaging procedures is needed to prevent contamination and infections.
The key considerations for the European Union (CE Marking) when manufacturing a bioabsorbable medical device is different. All devices need to carry a CE marking. A clinical evaluation is also needed. In some cases, clinical trials will also need to be performed. These measures are taken to demonstrate the safety and performance of the device. A risk management process is also essential. A quality management system that conforms to ISO 13485 needs to be established. Post-market surveillance systems also need to be put into place to monitor the performance of a medical device once it has entered the market and report any issues.
MATERIAL SELECTION -Vaupell can assist with the choice of materials and processes that provide optimal medical device and patient results.
Polylactic Acid (PLA): PLA is a renewable resource and is typically made from corn starch and sugarcane and is commonly used for bioabsorbable medical devices. As a base constituent of an implantable resin PLA is very biocompatible under the right conditions. It can be engineered to degrade over time ranging from months to years. It can be used for surgical sutures, orthopedic implants, drug delivery systems, tissue engineering, dental applications, disposable medical equipment, surgical meshes, and bioabsorbable stents.
Polyglycolic Acid (PGA): PGA is part of a family of synthetic polymers and is also considered a polyester. It is made up of repeating units of glycolic acid linked by ester bonds. It is biocompatible and can be found in surgical sutures, tissue engineering, drug delivery, and bioabsorbable medical devices. It is commonly used in conjunction with PLA to accommodate different degradation rates based on the application. It has good mechanical strength and degrades quickly, usually within a few weeks to months.
Polylactic-co-glycolic acid (PLGA): PLGA (a resulting blend of PLA and can be a good option for tissue engineering, surgical implants, and drug delivery systems. PLGA is very biocompatible. It is made up of lactic and glycolic acids which are bonded together in a chemical chain. These two chemical bonded acids allow for customization of different applications. PLGA degradation rates can be tailored allowing for new tissue replacement growth. It is also widely used in drug delivery which often requires a prolonged and continuous delivery.
Polycaprolactone (PCL): PCL is a synthetic polymer and is also considered a polyester. PCL is considered for a lot of applications due to being flexible to work with and having a low melting point. It is ideal for injection molding and 3D printing. PCL can also be used as a coating material for drug delivery systems that require a controlled release It is widely used for tissue engineering scaffolds, wound dressing, material coating for drug delivery systems, drug-eluting implants, and wound dressing.
Polydioxanone (PDO): PDO is a colorless, biodegradable polymer formed by repeating dioxanone monomers. It is widely used in thread lifts, suturing, tissue engineering, drug delivery and PDO sutures. It also offers long lasting wound support.
Calcium Phosphate Ceramics: Calcium phosphate ceramics is derived from a group of bio-ceramic materials and is very similar to human bone or teeth. It is widely used in the dentist industry for bone grafts, dental implants, restorative procedures and promotes bone regeneration. Is it also used in the orthopedic industry for implants, screws, plates, as well as bone grafts. These are often paired with PLA bases to achieve in bone devices with good bone replacement.
Process Considerations
Heat and shear sensitivity
It is extremely important to consider the material handling and processing of any bioabsorbable material. Heat and shear are necessary evils when processing these materials. These energy sources also degrade the materials. In essence, the manufacture of the devices is also the beginning of the degradation process.
Sterilization
There are fundamental types of sterilization: heat, chemical, and radiation. Each of these methods induce energy into the devices. Sterilization must be an element considered at the time of material choice as the wrong sterilization method can easily diminish the effectiveness of the device. For example, heat can be very effective in negating harmful microorganisms. However, heat will also degrade bioabsorbable resins.
Manufacturing – Tooling and Molding
Every contact surface that resins, or the resulting devices, touch must be considered for any effect to the materials. Surfaces must not allow any potential for contamination in a device, either on the exterior or the interior of the part. As the resulting implant degrades, any contaminant may be exposed long after the procedure. All surfaces must be evaluated from resin handling through final packaging to ensure no unwanted elements are introduced to devices.
Vaupell has been in business for 75+ years and has spent 45 years of that time providing solutions for medical devices and components. We’re a full product lifecycle partner to leading OEMs and promising startups.
It is very important to partner with a highly experienced design, development and manufacturing partner that understands the bioabsorbable material challenges and regulatory landscape to mitigate risk at each step of the process.