TRANSFORMATIVE SHIFTS IN MEDICAL DEVICE
PACKAGE QUALITY TESTING
Source: PTI Inspection Systems
Medical devices play a pivotal role in drug delivery by enhancing the effectiveness of life-saving therapies. However, their efficacy is contingent upon maintaining sterility of drug, medical device, and packaging en route to the patient, which entails inherent challenges. Different medical devices and packaging materials require versatile testing methods; meanwhile, limited regulatory guidance often results in misguided testing strategies. In 2016, revisions to the United States Pharmacopeia (USP) Chapter <1207>, which provides guidance on container closure integrity (CCI) testing and requirements, recommended a shift toward deterministic testing to meet the stringent criteria for maintaining package integrity.¹ Deterministic technologies can be readily controlled and monitored, yielding objective and quantitative data. Airborne ultrasound (ABUS) and vacuum decay are deterministic platforms that can be used to assess seal quality and package integrity, respectively, for a variety of packages, including those used for high-risk class II and class III medical devices.
THE ADVANTAGES OF VACUUM DECAY
Package integrity refers to a package’s ability to protect a medical device from external environmental contaminants like moisture, oxygen, and bacteria.² Ensuring package integrity requires effective testing, high-quality materials, and efficient, uniform packaging processes. Vacuum decay technology tests the critical physical attributes of a package and provides rapid quantitative results.
In the vacuum decay process, a package is placed inside a test chamber and vacuum is applied. The level of the vacuum is monitored using transducers over a set period. Changes in the vacuum level indicate that leaks and/or defects are present within the tested package. The test is both non-invasive and non-destructive to the package and its contents. For Tyvek lidded trays and semi-rigid containers, the process consists of masking off the Tyvek® layer and testing the integrity of the seal between the Tyvek® lidding bonded to the polymer or other rigid component. Vacuum decay verifies that there is no breach between the Tyvek® layer and the tub layer, assessing the integrity of the seal as well as the entire tub, and as a result, measuring and determining closure integrity.
The advantages are ample, including reliability, repeatability, accuracy, and robustness through validation. Vacuum decay’s versatility makes it suitable for a wide range of applications and package formats. It is also an ASTM Test Method F2338 referenced in the USP <1207> chapter guideline and an FDA consensus standard for package integrity testing. This CCI testing method is well-suited for the rigid and semi-rigid packaging used to contain medical device products such as cochlear implants, orthopedics, and sutures.
DELIVER HIGH-QUALITY PACKAGING WITH
ABUS TECHNOLOGY
Though it is sometimes misunderstood, seal quality refers to the bonding of the substrates within a package seal. ABUS is an ASTM Test Method F3004-13 and an FDA consensus standard for seal quality testing; it serves as one of the only true seal quality tests on the market. This non-invasive technique inspects the quality, durability, and performance of flexible package seals, like those used in Tyvek® pouches, a common package format for medical devices such as catheters and stents.
The ultrasound-based test consists of a transmit/receive relationship between ultrasonic transducers in which a signal is propagated evenly through a closed seal. Seal defects including non-leak defects are rapidly detected via variations in signal strength. Common seal defects include wrinkles, channel defects, misalignment, delamination, or blisters.³ By flagging if your signal is out of specification, this tool can help ensure that process conditions like temperature and dwell time are optimized. This method checks the entire seal edge to edge as opposed to other seal testing methods, like peel strength. The technology is high-speed, scalable, and easily integrated into various manufacturing environments and protocols.
ABUS is efficient for a variety of materials beyond Tyvek® pouches, including paper, poly, plastic, and foil. It can be used to test all substrates, including flexible, non-porous, and porous seals. As a non-destructive method, once the capital expense of the system is paid off, users save continually on sample testing.
Ultimately, the choice to implement ABUS and vacuum decay to assess seal quality and package integrity comes down to the approach that best suits the safety requirements of your package.
A SHIFT AWAY FROM PROBABILISTIC METHODS
Despite the benefits of ABUS and vacuum decay, many in the medical device world still use probabilistic testing methods that rely on the perception of operators to establish subjective results and produce minimal data. Generally, medical device companies use probabilistic testing to identify gross leaks only, typically 100- to 250-µm. When conducting a dye ingress test, operators may see channel leakage and assume that they have adequate information on seal quality. However, by definition, a breach in seal sterility indicates poor seal integrity rather than poor seal quality.
Dye ingress and bubble emission are destructive methods that effectively destroy samples to provide package integrity
data. In bubble emission, technicians look for bubbles that emerge from the package in a water bath, and in dye ingress, the telltale signal is blue dye in the package; both techniques are subject to human error. Manual visual inspection, another probabilistic testing method, relies on an operator’s visual inspection to assess whether a package has a leak. According to ASTM F1886, Standard Test Method for Determining Integrity of Seals for Flexible Packaging by Visual Inspection, current inspection methods encompass those that test for 75 µm channels with a 60% to 100% probability of channel leak detection. Due to these limitations, probabilistic testing methods tend to have relatively large margins for error.
CONCLUSION
As the industry moves to better utilize deterministic methods, consider the components of your med device packaging and what tests can best accommodate it. Though dye ingress and bubble emission have long served as industry standards, they only provide limited insight into package integrity. Alternately, ABUS and vacuum decay offer users improved return on investment (ROI), high-accuracy assessments, and safer packaging for medical devices, including implants, orthopedics, and stents.
REFERENCES
1. Stauffer, O.; Mullan, J. (2019, October). Shifts in Container Closure Integrity Test Methods. ISPE. https://ispe.org/pharmaceutical-engineering/september-october-2019/ shifts-container-closure-integrity-test-methods
2. Stauffer, O. Package Integrity: The single, most effective test for product quality. PTI. https://www.pti-ccit.com/about-pti/knowledge-center/articles/Vacuum-Decay-The- Ultimate-Solution
3. PTI. Seal-Sensor PQX. PTI. Retrieved from https://www.pti-ccit.com/about-pti/knowledge-center