Medical Device Link.

Originally Published PMPN January 2004

Package Testing

New package-testing technologies have achieved unprecedented levels of sensitivity, but just how sensitive do testing methods really need to be? 

The Institute of Packaging Professionals (IoPP) medical device packaging committee is conducting research to provide information about the thresholds for microbial penetration in device packages. “The current idea is that any hole is potentially dangerous, and so [device manufacturers] throw out everything,” says Laura Bix, PhD, chair of the IoPP Defect Characterization Task Group. Determining exactly what size hole presents a danger will allow manufacturers to “make informed, economically sensible decisions about the sensitivity of integrity tests while maximizing patient safety,” Bix says.

Bix, assistant professor at Michigan State University’s School of Packaging, is leading the effort. She and her team hope to have by March the techniques to determine whether microbes have entered the package tested. The current plan is to insert a needle through a self-sealing probe to aseptically fill packages with sterile agar. This would allow researchers to check for contamination without opening the package.

If the testing technique proves valid, a subsequent experiment will spray packages that have defects of varying sizes with B. subtilis and E. coli K-12, to see where penetration occurs when the driving force is gravity. 

To help determine whether contamination might occur during shipping, a third experiment will simulate the pressure differentials that packages face in the belly of an aircraft. Agar-filled packages (with varying defects) will be exposed to microbes in a vacuum chamber strapped to a vibration table. 

The results will not apply to all packaging. “The answers that we come up with will be specific to this package only, but it will be a start,” Bix says. 

The ultimate goal is to create a mathematical model where different factors—geometry of the hole, pressure differentials, thickness of the package material, likely microbial load—can be entered and the risks associated with a certain size hole can be determined.

Ultimately, however, Bix believes that incorporating microbe-detecting microsensors into packages—a technology not yet available—would render her research unnecessary. “When you come right down to it, it’s not holes that are the problem,” she says, “it’s microbes.” 

Copyright ©2004 Pharmaceutical & Medical Packaging News