Industry updates on ASTM methods

Discussions on ASTM package test methods were on the lineup at this year’s HealthPack conference, offering the medical device packaging community tips on using on existing methods as well as ideas for new ones.

Todd Dehmer of St. Jude Medical’s Artrial Fibrillation Division shared with attendees his case study on Test Method Validation using ASTM F1886–98 (2004) “Standard Test Method for Determining Integrity of Seals for Medical Packaging by Visual Inspection.” The method is only used for the visual inspection of seals and can be used to locate channel defects in both flexible and rigid packages with at least one transparent side. “It is impossible to use the method for all-foil laminations or for darker-colored trays,” he said.

ASTM F1886 has been shown to catch channels down to 75 µm wide with a 60–100% probability, Dehmer explained. “Visual inspection may not be used as the only method of package integrity testing during process validation studies, but should be used in conjunction with other standardized/validated test methods for determining package integrity and physical properties of component packaging materials,” he added.

New applications may exist for ASTM F1929 – 98 (2004) “Standard Test Method for Detecting Seal Leaks in Porous Medical Packaging by Dye Penetration,” explained Geoff Pavey, principal engineer of Oliver-Tolas Healthcare Packaging. The method is helpful in identifying channels and fractures caused by folding, punctures, and improper sealing or material selection, he said. “It can find channels equal to or greater than those created by a 50-micron wire. But using a syringe to inject dye into packages can be messy, and estimating the amount of dye to use can be challenging, Pavey said.

An alternative approach is the “edge- dip” method in which only a section of sealed material—not the whole package—is dipped into dye. “No needle or syringe is needed, but you have to cut away excessive material around the seal to test properly,” Pavey told the audience. “The amount of dye used is not as important because you only need a minimum volume to initiate capillary action.”

Key to testing success is exposure time, added Pavey. “Five seconds is plenty. Dye can wick into Tyvek and over time appear as a failure. Capillary action, which reveals channels, happens faster than wicking does. But wicking can occur in as little as 20 seconds,” he explained.

A draft standard is under development for testing package materials for abrasion resistance, reported Dennis Redding of Perfecseal Corp. Abrasion is a common occurrence, often caused by repetitive motion during distribution, he said. “It can be severe at stress points such as folded package corners, and it can contribute to stress cracks, tears, and punctures.”

Medical packaging converters do offer abrasion-resistant materials, but they are often the most expensive materials, Redding added. “We need a test method to determine how much resistance is needed so that materials are not overspecified,” he said.

Redding said that use of the Taber Linear Abraser has been investigated, but an interlaboratory study is needed. “The  current test fixture is designed to determine the abrasion resistance of flat films. It may be possible to rig a fixture that  would hold a lid-tray combination, but it would need to be proven to be reproducible and repeatable. The purpose of the test is to be able to predict performance and mimic stressful conditions. This test may bring the type of  reproducible results  that are needed to reduce the amount of distribution testing that is currently required.”

HealthPack 2010 will be held March 2–4, 2010. Visit www.healthpack.net.