Daphne Allen 
Researchers would like to soon answer this long-standing question: What is the smallest hole that will cause a breach of sterility in sterile medical packaging? Led by Laura Bix, PhD, assistant professor at Michigan State University’s School of Packaging, these researchers are now preparing to identify whether a 10-micron-sized or a 100-micron-sized hole results in significant ingress of microorganisms through normal Brownian motion or pressure differentials that mimic 8000 feet altitude. “This part of the study will tell us a lot,” says Hal Miller, a medical device packaging consultant and president of Pace Solutions LLC. “If there is no significant ingress at 100 microns, the study could very well stop there,” he says. “Current testing method sensitivity is often at 100 microns for many methods. If we do get ingress, more bracketing is necessary.” A look at secondary packaging may also be necessary, he adds.
Originally starting out as a task-group study within the medical device packaging technical committee of The Institute of Packaging Professionals (IoPP) in 2002, this research has taken on a life of its own. Under IoPP member Bix, Michigan State University (MSU) School of Packaging re-searchers managed the project. In the last few years, they have developed a whole-package microbial challenge test and quantified laser hole sizes.
Depending on study results, future work involves running the experiments with statistically significant samples for statistical validity, says Miller.
Several supporters have donated materials and services, reports Bix. Miller, however, fears that “MSU has hit a wall” in terms of continuing the project without significant industry funding. “This study is too important to let it go by the wayside,” he says. “We need sponsors to provide monetary support.” The School of Packaging needs $140,000 to recoup out of pocket costs and to complete the project, report Miller and Bix. The project will be taken out of the IoPP task group, and study updates and results will be made available to the study contributors. “However, because the issue is so critical to the medical device industry, the research results will be made public,” they say.
Research study participants are being asked to contribute $5,000 to the project. According to Bix and Miller, current goals include:
• Using the newly developed whole package microbial challenge method, the researchers will attempt to determine the effect, if any, of pressure differentials on packages with defects of 0, 10- and 100-µm holes. “A wider variety of hole sizes would create undue expense,” says Bix. “These two hole sizes should sufficiently bracket results and provide guidance for future research.” This part of the study is expected to be completed by August 15, 2006.
• Providing a validated method written to withstand regulatory and peer scrutiny for a whole-package microbial challenge test. This method is expected to be written by May 15, 2007.