Physical Testing Of Medical Packaging

By Ed Emerson

In a world full of hungry microorganisms, it is critical that medical devices, designed to heal, do not inadvertently do the opposite by infecting the patient. To prevent infection, a device’s packaging or “sterile barrier system” must maintain sterility over the product’s entire shelf-life. In fact, packaging can be the weak link in the chain of steps designed to keep a product sterile from production to final use.

Traditional Sterility Testing
Responsibility for maintaining safety and sterility is shared by development engineers, packaging developers, packaging managers, product managers, and quality auditors. A traditional way of testing a package’s sterile barrier system at any point in its life has been to bathe it in a contaminated solution and then test by culturing the contents to be sure that microbes have not penetrated the package. While workable, this microbial challenge testing has several drawbacks. First, because culturing is a growth process, it is invariably time consuming. Second, errors in handling the package or its contents in the testing process can lead to accidental contamination and hence, costly false positives. Finally, there is also a risk of false negatives if the microbes used in testing behave differently than expected.

Opening the Door to Integrity Testing
For all these reasons, there has long been discussion of using package integrity testing instruments to support or replace traditional sterility tests. In 2008, the FDA finalized guidance regarding “container and closure system integrity testing...as a component of the stability protocol for sterile products.” The guidance states that physical testing can be used to verify that seals are leak free and continuous.