One way to reduce costs is to improve best practices and cut out unnecessary steps that waste time and materials, and add cost.
For example, what really determines sterility assurance levels (SAL) or how sterile a product needs to be? Does a SAL of 10-3 provide enough assurance of safety and sterility? Does a SAL of 10-6 provide an excessive amount of security—which can drive up costs? And how does SAL vary with the type of device? Another area of cost control is refining the terminal sterilization of packages and drugs so that the process requires a smaller dose than what is currently accepted. Using a smaller precise dose of radiation within tight tolerances can be an effective alternative to sterile fill operations or other sterilization methods, saving time and money.
There often are increased sterilization challenges for newer, innovative products entering the market. Many of these are combination products or tissues/biologics that generally do not lend themselves well to traditional test methods and sterilization or process validation. Combining these with the trend toward personalized medicine and just-in-time delivery “means that more and more unique products will require very fast turnaround time for sterilization,” said Emily Craven, marketing manager for Nordion Inc., a Canadian provider of gamma sterilization technologies, including irradiator equipment and cobalt-60 sources. “Sterilization systems, whether at a manufacturer’s site, a contract facility or hospital environment must be able to meet these demands.”
Speed and Efficiency
Speed to market for new product development and routine processing is a top priority for OEMs, regardless of sterilization method. Other important concerns are having an effective validation program in place for the sterilization process, maintaining process effectiveness, rapid throughput turn times for processing, electronic data sharing and an efficient release program for sterilized products.
“Package reduction—footprint, height, weight and packaging waste—is also a top priority,” said Seán Egan, group marketing manager for Nelipak Healthcare Packaging, a Cranston, R.I.-based developer and manufacturer of custom-designed thermoformed packaging with operations in Phoenix, Ariz.; Costa Rica; the Netherlands and Ireland. “Reducing the package maintains competitiveness and increases pallet loads through sterilization and transportation, reducing unit cost.”
More OEMs are seeking contract manufacturers that provide in-house sterilization services. This shortens the supply chain, improves communication and maximizes control over the sterilization process, making it easier to customize a very specific set of dosing requirements and processing speeds, or improve the efficiency of just-in-time manufacturing.
“Most OEMs prefer working with fewer contractors to better manage quality control, which means they lean toward in-house sterilization services,” noted Chookiat Chanarat, managing director for Infus Medical, a Thailand-based full-service contract manufacturer for single-use class II and class III medical devices that provides ethylene oxide (EtO) sterilization services. “Having this service in-house reduces operating costs for the OEM customer and saves time by not having to manage additional sterilization contractors.”
Companies also increasingly are concerned about mitigating risk to the supply chain pipeline. More OEMs are focusing on business contingency planning for all aspects of production, including sterilization and packaging.
“Given the importance of continuity of supply in medical device packaging, it is essential to have a plan in place should this supply chain break down for any reason,” said David Moore, business development manager for SteriPack USA, a Lakeland, Fla.-based provider of cleanroom sterile packaging solutions. “If there is a natural disaster and your converter’s facility is affected, what are your options? Do you have the time to validate and approve another supplier’s packaging? Is it worth taking the risk to only have a single source for your medical packaging? These are the types of questions that seriously need to be considered when developing a contingency plan.”
Improved Testing Methods
Although no significant technology advances in sterilization and packaging have been made in recent years, many of the standards that pertain to package testing are evolving to address deficiencies and update relevant scientific knowledge. For example, shipping and distribution testing is updating its vibration sequencing to more accurately mimic real-world conditions, rather than the excessive cycles that currently are required. This will provide a more accurate representation of how a shipping system actually performs. There also has been a significant development in dye migration testing. Dye migration has added an edge dip method in addition to the long-standing injection method for testing porous packages. The injection test uses gravity to allow the dye to move through a channel, whereas the edge dip method relies on capillary action. Both tests are very effective at detecting any channel breach.
A new method for seal peel testing of trays is in the early stages of development. The current method cuts coupons for testing under ASTM F88, which may not be the most appropriate approach for all cases. The new approach is to clamp the tray into the stationary grips and have a one-inch-wide section of the lid pulled while still attached to the tray.
“It is difficult when cutting trays to accurately cut a one-inch-wide coupon,” said Wendy Mach, packaging section leader for Nelson Laboratories Inc., a medical device testing laboratory based in Salt Lake City, Utah. “If special care is not taken when cutting the coupon from the tray, different failure methods than the standard peel can result. When cutting the plastic tray, it becomes difficult to get a smooth cut that complies with the standard width requirement—this can actually affect the results when the coupon is pulled with the tensile tester. Additionally, when clamping a tray coupon, there is often deformation resulting in a change in the peel angle. The new approach will clamp directly onto a flat surface resulting in a uniform peel angle.”
Parametric release is now an established methodology for medical devices that are processed with ethylene oxide. The process requires direct measurement and specification of additional sterilization parameters, such as ethylene oxide concentration and relative humidity. Once these additional specifications have been validated, it is possible to discontinue the use of biological indicators for process release—eliminating the typical seven-day delay associated with this test.
“This benefits device manufacturers by shortening and optimizing sterilization turn times that are now driven by product aeration times [the amount of time product is held at controlled conditions to ensure safe levels of EtO in medical devices],” said Peter Strain, vice president of technology for Sterigenics’ SteriPro Labs. “This shortened turn time benefits manufacturers by speeding up time to market for custom devices and reducing working capital by reducing inventory costs for high-value or large-volume devices.”
The growth of biologics and combination drug/device products also brings about more challenges for packaging materials and sterilization methods. For example, these products may require low temperature sterilization or be incompatible with radiation.
“On the material side, considerations include no interaction with the drug, low leachables and compatibility with the required sterilization methods,” said Marc Bandman, North America marketing manager for DuPont’s Medical and Pharmaceutical Division in Richmond, Va., which provides the well-known Tyvek product series for medical packaging.
Craven noted she is seeing an increased number of sensitive products that can’t handle the traditional higher doses associated with radiation sterilization in the 25-50 kilogray range. (A kilogray is a derived metric measurement unit of absorbed radiation dose of ionizing radiation). This trend largely is driven by material considerations of specialized polymers that provide a specific device function, but may not be well-suited to radiation sterilization.
“Contract gamma sterilizers and in-house systems are able to mitigate this by optimizing their processes to provide tighter dose ranges,” she said. “Medical device manufacturers are also qualifying lower sterilization doses so that doses can be reduced overall. Devices may also be irradiated at lower temperatures, such as irradiation with dry ice, or packaged in oxygen-free environments to minimize the radiation side effects on some of these more sensitive materials.”
Get Ready for Tyvek
DuPont’s Tyvek medical packaging materials are highly popular because they don’t generate many particles when opening a package—a result of being made from continuous filaments, not short fibers like papers. Tyvek also resists tearing. When papers are torn during opening, or are abraded, short fibers may be released to the device, or the environment.
Now, DuPont soon will fully commercialize its Tyvek “Transition Protocol Materials” that have been in development for several years. DuPont is coordinating the change process using a U.S. Food and Drug Administration (FDA) transition protocol and is periodically issuing new information and test data to prove functional equivalency of the new transition materials to the current 1073B and 1059B products. The change involves moving production of Tyvek 1073B and 1059B to the latest flash spinning technology and equipment. It is expected that FDA approval will be granted by the third quarter of 2015.
DuPont’s equivalency letter alone may not be enough to prove equivalency in all cases, however. It would be prudent for individual manufacturers to confirm equivalency by performing their own validations. This especially is true for the EtO sterilization process. Are the products packaged in the various packaging configurations with the new Tyvek easier or harder to sterilize with EtO? The parameters set for EtO sterilization often conflict with the requirements for product release. “An EtO process may have a more robust sterilization result in terms of sterility of the product, but that robustness may increase the level of EtO residuals on the product that have to be removed prior to release for patient use,” said Mike Rahn, director of SteriPro Laboratories.
This Tyvek change also may be more significant for OEMs that use EtO sterilization as their terminal sterilization process. While form, fit, function and stability may be proven as functionally equivalent, or even improved for the manufacturing packaging process with the new Tyvek, the impact to the EtO sterilization may need to be evaluated by the OEMs for their existing validated processes.
DuPont already has rolled out controlled sales of its Tyvek transition material. That means the new material is available for manufacturers to purchase for validation work. Each company that uses Tyvek in its packaging will need to address the transition, using a risk-based approach to determine if they need to completely revalidate, if they can use the DuPont equivalency letter as part of a written justification, or if something different is required. Because Tyvek is a major component of many medical device packages, this transition affects the whole industry.
Future Challenges
Newer, more complex medical devices—especially combination devices or tissues/biologics—often require a different testing and sterilization approach because the typical methods are not completely effective for these products. Therefore it is up to the medical device manufacturer and its partners to create methods that will deliver results that satisfy the FDA—which can be a little unsettling because there are no hard and fast FDA standards to follow.
For example, some tissues/biologics are gels or powders; a typical extraction for a bioburden test (as would normally be used on a solid medical device) will not allow for membrane filtration.
“This often pushes laboratories to use a different approach such as a spread plate, but that often results in a reduced ability to detect the presence of microorganisms,” said Martell Winters, senior scientist for Nelson Laboratories.
Tissue products often are manufactured in small batches, or with a large amount of variability in the size of finished product. Typical validation approaches such as radiation sterilization usually work under the assumption that all products in the batch are identical. “When this is not the case, such as with tissue products, it can be difficult to determine which product types or sizes should be used for testing purposes to accurately represent the batch,” added Winters.
Over the years, Nelson Labs has developed several alternative approaches for tissue/biologics/combo products. It often will implement the most probable number approach for bioburden testing of tissue because it provides more sensitive data than an extraction and filtration or spread plating.
“Performing a comparison study is another option for demonstrating that the tissue carries the same bioburden level regardless of size,” said Winters. “This allows the company to use a variety of tissues for validation purposes, rather than having to provide a large number of the worst case sizes.”
Sterigenics has noticed an increased emphasis on providing ISO or FDA reviewers with information and data to support expiration dates on packaging. Conversations with OEMs now include accelerated aging for the purpose of determining shelf life as it relates to product functionality/efficacy and packaging integrity, during the initial discussions involving sterilization process development.
“In the past, the topic was not always on the radar screen initially, or came up later after the product was on the market,” said Bill Young, vice president of global for SteriPro Consulting and Laboratories. “In addition, many OEMs are coming back and asking for methodology to extend shelf life claims of existing products. For example, they have data that support two years of shelf life, but now want to extend that to five.”
The FDA continues to raise the bar for packaging, with increased scrutiny on the risk of particulate contamination within the package. Contaminants may include cellulosic material, metal particulates from machinery at the packaging plant or even glass in vials.
“Leaders in the industry, starting with drug and high end devices, are working on full characterization,” said Bandman. “In some cases, techniques are being borrowed from the electronics industry to be able to find and characterize the contamination. It’s then important to work collaboratively and openly with suppliers to seek out potential sources for the identified contaminants, through the entire supply chain.”
There is plenty of discussion in the industry about establishing alternate sterility assurance levels in medical devices. The regulations are clear that if a medical device will be in contact with compromised human tissue that the SAL should be 10-6—meaning there is a one in 1 million chance that a device coming out of a terminal sterilization process has a viable microorganism. AAMI (Association for the Advancement of Medical Instrumentation) ST-67 provides guidance on choosing an alternate SAL for medical devices that cannot withstand a sterilization process using conventional methods to 10-6. Now, the international community, through an ISO technical committee, “is looking at whether or not a risk-based approach to the choice of alternate SALs should be adopted globally,” said Craven. “There is some discussion around whether or not this opens the door to products with less assurance of sterility from companies who don’t want to go through the rigor of exploring different sterilization modalities versus companies with a new life-saving product that now can be brought to the market with a path to sterilization.”
The best way for OEMs to make the packaging and sterilization process go as smoothly as possible is to work with their contract manufacturers to identify the best approach early in product development. This not only includes the packaging design but also the analysis of new formulations in materials that may be easier to sterilize in a functionally equivalent manner.
“For sterilization and packaging solution approaches, early-stage interaction with the OEM/brand owner allows for the greatest probability for resolving the OEM’s challenging requests,” said Chanarat. “Early interface with the OEM is essential for achieving this. It is a good opportunity for both the OEMs and the contractors to work together efficiently and to exchange the necessary capabilities information to find the best alignment between the product design requirements and the capability services offered by the contractor. Good cooperation and communication between the contractor and the OEM is key to prevent misunderstanding and making the changes that balance cost savings with product design flexibility and effectiveness, without compromising product quality.”
As more medical device companies operate on a global basis, the expansion from domestic to foreign markets also can bring more unforeseen challenges for sterilization and packaging. One that Moore with SteriPack USA has personally witnessed is a lack of packaging uniformity, which can create customer confusion.
“Whether you are selling into the Asian, South American or European markets, it is essential to ensure the look and feel of your product’s packaging is consistent,” said Moore. In many cases, he adds, packaging is not something that is sourced centrally, but rather in the region that the product is being sold, which can lead to inconsistency. “We can provide consistent packaging in all major markets as our global manufacturing locations in Malaysia, Ireland, Poland and the United States all use the exact same equipment and adhere to the same quality system—providing a ‘like-for-like’ product, no matter the marketplace.”
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. His clients range from startups to global manufacturing leaders. He also writes a variety of feature articles for regional and national publications and is the author of five books. Contact him at mark.crawford@charter.net