Set procedures for the testing sequences of distribution test cycles are available through standards organizations such as ASTM and ISTA, but the acceptance criteria can be more difficult to define. As in any design, the requirements for this acceptance criteria need to be set forth by the end user. Simply specifying that the package does not show damage is insufficient. It is common to require further primary package testing after the completion of the secondary package study to prove that the product is still adequately protected.

Visual inspection is an important first step, meaning looking for defects in the primary package. If such an inspection does not take place before testing, the technician cannot be certain that any defects found at the end of the testing are a result of the test itself. The inspection procedure must be controlled through a protocol, making sure that the inspection station has sufficient light and access to magnifying devices. It is also critical that any pretesting inspection does not include the type of destructive tests that would be appropriate after the study is concluded.

In order to properly design the acceptance criteria for post-inspection testing, the original package specification should be used and the testing lined up with the functional requirements. For example, if the package specifies a particular seal strength, then confirming that the tested samples continued to have that seal strength is appropriate. Once again, one should start with a visual inspection to ensure that there are not any obvious defects in the package that were not there prior to the testing. Non-destructive testing (such as visual inspection, dimensional confirmation) can be performed prior to the shock and vibration portion of distribution testing. However, destructive testing of the primary package can be performed after the distribution study to determine acceptability. If the overall package integrity needs to be examined, a bubble leak test is appropriate as it can find small leaks in the seals or package surfaces. If there is a concern about the strength of the package being compromised, then a tensile test measuring the strength of the seal area is a good choice.

Cryopak regularly conducts an assortment of primary package tests. We can match the package specification with the inspection test and also provide guidance on reasonable sample sizes. Please contact us to learn more about how we can help.

Authors:
Anthony Alleva, Technical Director
Eva Langen, Packaging Development Manager