In order to consistently produce packaging capable of protecting its contents throughout the stated shelf life, it is important to evaluate the strength characteristic. Not only does strength play a key role in a shelf life package validation, but it also allows the medical device manufacturer to determine the consistency of their sealing process and adherence to design specifications.
Within the medical device industry there is occasional confusion regarding the differences between a package’s strength versus the integrity of a package. Package strength relates to the force required to separate two components of the package such as the force required to separate two flexible components of a pouch or the force required to separate a flexible lid from a thermoformed tray. These forces are commonly measured in pounds of force per inch width, as in the seal/peel test; or in pounds per square inch, as in the burst test method. Alone, package strength values do not necessarily prove the integrity of the entire package. As an example, while a seal strength measurement may be within the design specification that same seal may have a channel leak that would be found using dye leak testing indicating a breach in package integrity. It is the combination of strength and integrity testing that proves out the ability of a package to do its intended job.
The main cause for failing package strength testing is the sealing parameters. If a proper process validation of the sealer is not performed, then the medical device manufacturer can expect failure during strength testing.
ASTM Test Standards for Packaging Strength
ASTM D3330 – Package Strength Testing by Peel Adhesion Testing
ASTM F88 – Package Strength Testing by Seal Peel Testing
ASTM F1140 – Package Strength Testing by Burst Testing
ASTM F2054– Standard Test Method for Burst Testing of Flexible Package Seals Using Internal Air Pressurization Within Restraining Plates