By Brandon Muhlestein, Packaging Consulting Study Director
Over the past few years, as medical device manufacturers look for new and innovative ways to package, sterilize, and market their products, the use of non-porous materials in packaging has become more and more popular. Similar to porous packaging, non-porous packaging also comes in a variety of options such as blister packs, all foil, all polymer (poly), and combinations of foil and poly. Since non-porous packaging has as many options as porous packaging, what criteria can manufacturers use to select one type of non-porous packaging material over another? When selecting a package, the most important thing to consider is the end use and purpose of the packaging. For example, if the product is light sensitive then a foil/foil pouch would be a more appropriate selection than a poly/poly style of pouch; as the foil/foil pouch would prevent light from affecting the contents inside. Other considerations include, but are not limited to: the sterilization method used the packaging process (i.e., vacuum or not vacuum sealed), the transporting or shipping method, and the actual contents that will be packaged.
Example of a Foil/Foil pouch
Non-porous packaging configurations must meet the same packaging requirements as porous packaging configurations. ISO 11607-1 Packaging for terminally sterilized medical devices – Part 1: Requirements for materials, sterile barrier systems, and packaging systems; provides the minimum requirements that terminally sterilized devices must meet regardless of whether the packaging is porous or non-porous. The standard states that a sterile barrier system must be able to maintain its strength, integrity, and microbial barrier until the end of the intended shelf life. However, some of the tests available to show that the packaging meets the requirements may vary slightly depending on which configuration and material combination are selected.
Before any testing can begin, the test protocol must be written and approved. The protocol usually includes; material selection justification, product details, sealing parameters, sample sizes, test methods, acceptance criteria’s, etc. Without a formal test protocol it is difficult to determine what to do, how to do it, and whether the testing was successful or not.
An important part of the package testing is the transportation and distribution testing (i.e. ship testing). This testing is conducted to show that the shipping container and shipping system provide adequate protection to the sterile barrier inside. The most commonly used ship-testing standards are; ASTM D4169, ASTM D7386, ISTA 3A, and ISTA 2A. Ship testing subjects the shipping container to a series of tests that simulates what the container could see throughout the actual distribution process. For example, compression testing would simulate warehouse and vehicle stacking; shock testing would simulate a drop from a conveyer belt or when handling; and vibration testing simulates the shock of traveling (over roads, rail, or through the air). Remember, that testing the packaging and distribution process in a lab setting is more controlled than performing the test in a non-lab setting or under normal shipping conditions. When selecting a standard, make sure that it is recognized by the regulatory body you are planning to use as they may require testing to follow a specific standard, or justification as to why the test method was selected.
After the shipping tests have been completed, the next step will be to test the sterile barrier to determine whether the shipping container or system provided adequate protection. This is usually when the actual package testing begins. This testing is classified as baseline, or T= 0, because the data represents how the sterile barrier functions as it would arrive at the end user. The testing incorporates, at a minimum, one test from each of the three previously mentioned categories (strength, integrity and microbial barrier). There are a few standards that have been developed specifically for non-porous packaging systems. For the integrity category, ASTM F3039 Standard Test Method for Detecting Leaks in Nonporous Packaging or Flexible Barrier Materials by Dye Penetration; was developed as the preferred standard for performing the Dye Migration test on non-porous packaging systems. This standard is applicable to packages that are either clear or opaque. In 2015, ASTM F2981 Standard Test Method for Verifying Nonporous Flexible Barrier Material Resistance to the Passage of Air; was released as a way to prove that the materials being used in the non-porous packaging system are truly non-porous and thus meeting the microbial barrier requirement of ISO 11607-1.
At the same time the baseline packaging testing is being performed, the accelerated and real-time aging should be started. The table below breaks down the basic differences between accelerated vs. real-time aging:
The purpose of any aging study is to show that the sterile barrier can be maintained through its intended shelf life. Package testing will need to be performed not only at the baseline time point, but also at the end of its intended shelf life. In shelf-life studies longer than two years, adding an interim time point, or two, reduces the risk of a failed validation. For example, if the product’s shelf life is expected to be five (5) years and you wait until the very end of the accelerated aging to test the packaging, if there is a failure there is a high chance of having to start over or repeat the testing. This can be both a significant cost and time issue. However, if you had tested the packaging at interim time intervals (i.e. 2, 3, and 4 years), you could fall back to the last point in time that the testing passed and introduce the product with that time point as an initial shelf life.
Once all of the testing has been completed, the data needs to be reviewed to determine whether or not the device passes. This is accomplished by compiling the data from all of the different test phases and comparing it to the sample acceptance criteria listed in your protocol, and evaluating any change over time that may have occurred. Assuming the data is acceptable, the next step would to be file with the FDA or other regulatory body; and once cleared, go to market.
Non-porous packaging has become a flexible, cost-effective alternative to its porous counterparts. However, the testing for these packaging solutions will need to be as rigorous and comprehensive as that for porous packaging options.