ASTM Packaging Standards: Medical Device Packaging

Part 6: Medical Device Packaging Challenges

Medical device packaging often has to maintain a sterile barrier from the point of sterilization until the moment of use in a hospital or clinic. The packaging, commonly a pouch, tray with a lid, or a blister pack, must withstand sterilization processes, like ethylene oxide gas, gamma irradiation, or steam, without degradation, and then protect the device during shipping and storage. A single pinhole or seal breach could render a normally safe device unsterile and put patients at risk.

Medical device packages typically use combinations of porous materials, to allow sterilant entry, and plastic films. This means that managing the interface or seal between these dissimilar materials is a key challenge. Aging is also critical. Many sterile device packages have 2 to 5 year shelf lives, therefore manufacturers must prove that the seals won’t deteriorate over time.

Additionally, the industry is highly regulated (ISO 11607 and FDA’s Quality System Regulation set out specific requirements for packaging validation), therefore demonstrating compliance through recognized standards is part of the approval process.

Another challenge is that device packaging is often opened in sterile fields and packages need to open cleanly without contaminating the device, which ties back to proper seal strength and design. This is not directly an ASTM test issue, but part of the overall packaging quality.

ASTM Standards and Solutions for Medical Device Packaging

The medical device sector relies on a comprehensive array of ASTM standards to validate sterile barrier systems. Many of these have been mentioned already, as this industry arguably prompted the development of some key standards. A typical validation for a new medical device package will include Visual inspection (ASTM F1886) of seals to ensure no obvious defects. Seal strength testing (ASTM F88) to quantify the strength of seals and ensure they meet minimum requirements throughout the pouch. Dye penetration (ASTM F1929) to detect any micro-channels or pinholes in seals. And bubble leak test (ASTM F2096) to find any gross leaks that could compromise sterility.

These tests in combination provide high confidence in seal integrity. In fact, the ASTM F1929 dye test is sensitive enough to detect leaks equivalent to a 50 µm wire, as noted, which is more than sufficient to catch defects that could admit bacteria. For rigid or semi-rigid medical packages, like thermoformed trays with Tyvek lids, vacuum decay testing (ASTM F2338) is also used as an alternative to dye tests, offering a non-destructive option to test whole packages.

Accelerated Aging (ASTM F1980) is performed to simulate the passage of time. The packages are aged at elevated temperature and humidity, then pulled at various intervals such as 1x, 3x, 5x the intended shelf life, and put through seal strength and integrity tests again. This ensures the sterile barrier will last until expiration.

On the shipping side, ASTM D4169 test cycles are mandatory for sterile medical device packages. Typically, Distribution Cycle 13 or 4, depending on package weight and shipping mode, is chosen. This test includes drops, vibration, compression, and altitude tests to represent the worst-case distribution scenario for the product. After conducting D4169, the packages are usually subjected to leak and seal tests again, this is known as post-distribution integrity testing. It verifies that after withstanding simulated shipping, the packages still have no leaks (per F1929/F2096) and maintain seal strength above the required minimum.

This approach of combining environmental conditioning, distribution simulation, and integrity testing is essentially what ISO 11607, the international standard for medical device packaging, prescribes. ASTM standards are the test methods that fulfill those requirements.

Solutions and Best Practices for Medical Device Packaging

Given the high stakes, medical device companies often adopt a worst-case testing philosophy. This means that the test is performed to more extreme conditions than necessary to build in safety margins. For instance, they may test seals with dye penetration at not just the end of shelf life, but after accelerated aging, the extreme temperature cycling, the transit testing, and all combined, in order to ensure the packaging can handle an arduous journey and long storage and still remain sterile.

Since sterilization can weaken seals or materials, a test must be performed on sterilization impacts. This means that an entire validation is done in sequence on packages after they’ve been sterilized by the intended method. ASTM F1980 provides guidance on including real-time aging or additional stresses if needed.

From a compliance standpoint, virtually all the ASTM methods mentioned (F88, F1929, F2096, F2338, D4169, F1980, etc.) are recognized by the FDA as consensus standards, meaning that if a company follows these methods and meets the criteria, they can cite the compliance in their regulatory submissions (510(k) or PMA). This significantly smooths the approval process.

To maintain compliance, companies have detailed procedures and training for these tests in-house or they use certified packaging test labs. It is a best practice to perform an Annual Package Integrity Audit – pulling samples from production and performing a full battery of ASTM integrity tests to ensure nothing has changed in materials or processes that could affect packaging. This aligns with FDA’s expectation of continued process verification.

The medical device packaging field, through groups like the Sterile Barrier Association, also continuously updates test methods. For example, recent updates have been made to ASTM F1929 dye test methodology.

Companies must stay current to ensure they are using the latest and most reliable techniques. All these efforts boil down to a simple goal: when a surgeon opens a sterile package, they can trust that the device inside is pristine and safe. ASTM packaging standards provide the technical backbone to achieve that trust.