Pharmaceutical and Medical Packaging News Magazine
PMPN Article Index

Originally Published March 1998

MEDICAL

Package Testing: Is Standardization on the Horizon?

Some groups are working to standardize package testing in the device industry, but will it be enough?

by Karen G. Beagley, Midwest Editor

Package testing is an essential step in the medical device manufacturing process, because if a package fails, the sterility of the product is compromised. But determining which package testing procedures to use and what the results mean can be tricky, leaving many device manufacturers calling for industry standards.

Their calls may have finally been heard. Different organizations are now in the process of recommending standards to ensure that device manufacturers, at the very least, have adequate instructions for package testing. These standards will not only give instructions but will also help with choosing the appropriate test.

ACHIEVING STANDARDIZATION

"The Food and Drug Administration (FDA) has minimum requirements that any package must meet," says Kent Hevenor, product manager, Sencorp Systems Inc. (Hyannis, MA). "Most companies test at larger thresholds than FDA requires."

"FDA has stated that the major current problem with test methods submitted to them is that there has been insufficient validation data on the method used for package integrity testing," says Don Barcan, president and owner of Donbar Industries Inc. (Long Valley, NJ). "FDA is anxious to work with any organization in addressing the issues of package integrity testing. In my opinion," Barcan continues, "the issue is finding a validatable package integrity test method that correlates to microbial recontamination under real-world conditions. It is possible that more than one test method will be required."

Seal strength is one of several tests routinely performed on device packages. Photo courtesy of DuPont Nonwovens, Wilmington, DE

Since there is a lack of package testing standardization, many manufacturers validate the tests themselves. This is costly, however, and the results are open to interpretation by each company. Some manufacturers are beginning to standardize their own test methods. "Many companies test to failure and then use that information to set their standard," says Jim Mills, engineer, Ethicon Endo-Surgery Inc. (Cincinnati). "Of course, these results will be different with each material used, the material's weight, etc."

"We tried several different methods for testing pouches," explains Mark Leuenberger, staff packaging engineer at Ethicon. "With each variation, there were different results. It proved we needed to standardize our testing procedures throughout our company. Given a pouch, I can give you the test results you want without changing the pouch, just by using different test method variations. In addition, the United States and Europe have different standards for sample width and separation speed."

The motorized seal-strength tester from Vinatoru Enterprises measures the seal strength between a flexible lid and thermoformed tray or between two flexible materials at a pull angle of 180°.

By restraining the package and using a pressure-decay leak test, the BT-1000 unit from T.M. Electronics can determine the integrity of a seal.

ISO 11607 includes a reference list of package tests in its appendix. "ISO 11607 talks in general terms about all the different things that are required to validate a package," says Tim Early, marketing specialist at DuPont Nonwovens Tyvek (Wilmington, DE). "The reference list gives a manufacturer review materials but also gives lots of flexibility for package testing. Several of us wanted to add an in-depth guidance document to 11607 on package testing. FDA claimed that adding it to 11607 would make it a standard and would change the meaning of 11607."

In answer to this lack of standardization, several groups are working on package test validation. The American Society for Testing and Materials (ASTM; West Conshohocken, PA) is working on standardization for seal strength testing, visual testing, and dye penetration. "ASTM is developing a standard burst test for rigid blisters," says David Bohn, package engineer at Medtronic Inc. (Minneapolis). "At its April meeting, ASTM will address the comments we received on this test."

The Flexible Packaging Association (FPA; Washington, DC) has published several standard test methods. "FPA's Sterilization Packaging Manufacturers Council technical group is working with ASTM to standardize package tests," explains Marie Tkacik, engineering manager for Tolas Healthcare (Feasterville, PA). "The group includes myself and representatives from Beacon Converters, Rollprint Packaging, Oliver Products, Perfecseal, and Rexam," she adds.

To date the group has published standard test methods on: average peel strength value of flexible barrier materials; burst and creep package testing using internal pressurization; seal integrity dye penetration method; detection of leaks in heat seal packages internal pressurization method; maximum seal strength value of flexible barrier materials; determining porosity of flexible packaging materials (Gurley densometer method); coating/adhesive weight determination; and seal integrity visual inspection.

CONCLUSION

Although progress is being made in the area of package testing standardization, much work still remains. A clear concensus will go a long way in simplifying the testing process which, in turn, will lead to better packages.

Methods to Aid Package Testing

There are several companies working on revising or developing new test procedures. One such test is the Sealcheck 210 package testing system from True Technology Inc. (Newton, MA). The system provides repeatable and nondestructive quality control of the sterile integrity of medical device packages with porous, gas-permeable membranes. These include thermoformed trays with porous lids and flexible pouches with one porous side.

"Until now, medical device manufacturers have had to rely on a variety of techniques for integrity testing that include visual inspection, dye penetration, microbial challenge, and burst testing," says Louis Slaughter, president of True Technology. "The first method is highly subjective, while the latter methods destroy the packages they test. This means that only random samples can be taken, and there is no way to verify the sterile integrity of the packages that are actually shipped."

With Sealcheck 210, a temporary barrier layer is applied over the package membrane using a special tape. Next, helium tracer gas is introduced into the package through a port in the barrier tape. A probe maps the helium concentration using a mass spectrometer leak detector and reports the location of any leaks found, whether in the seal between the permeable membrane and the thermoformed tray (or pouch), or in the package walls themselves.

"We are the first application of this test from True Technology," says John Spitzley, associate fellow — packaging at Medtronic Inc. (Minneapolis). "This test is nondestructive and less time consuming than previous testing procedures. It can easily be integrated into the production cycle."

Work is being conducted on restrained-plate seal-strength testing in flexible packages. "Restrained-plate testing allows the pressure to be uniformly applied to the seal area without being influenced by the package geometry such as chevrons or material characteristics such as stretch," says Dean Andrews, sales manager, T.M. Electronics Inc. (Worcester, MA). "Only the seals can deflect with pressure so that only the weakest area of the seal will be broken during the test."

Restrained-plate testing is useful for leak testing the integrity of closed packs with nonporous materials such as film or foil laminates. The patented T.M. Electronics' Package-Port provides a leaktight path from the package to its BT-1000 instrument so that a closed pack can be effectively leak tested.

Instron Corp. (Canton, MA) has recently introduced smaller versions of its materials testing systems. "Model 4440 and 5540 single-column materials testing systems are physically smaller for those production lines that have less space," says Dick McManuis, product manager at Instron. "These models can be set on a tabletop."

A horizontal seal-strength tester has been developed by Vinatoru Enterprises Inc. (Pompton Plains, NJ). "The crosshead moves from right to left so the product stays in the package," says Mihai Vinatoru, president. "Our motorized seal-strength tester for rigid and flexible packages is designed to measure the seal strength between a flexible lid and thermoformed tray or between two flexible materials, at a pull angle of 180°."