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How to test the microbial barrier properties of the seals of a coated Tyvek® // coated Tyvek® pouch. (1) What will be the regulatory agency (FDA and EU) acceptable test method(s) (2) Specifically, the acceptance criteria of each testing method, if any?

Last Updated On April 16, 2008

Guidance on barrier properties assessment is provided in ASTM F2097 Guide for Design and evaluation of Primary Packaging for Medical Products. This document was developed in 2003 by the SPMC and was then taken to ASTM for development as a consensus standard. Included in the barrier property section of this document are several methods of testing a sterile barrier system.

Among the test method choices the two most commonly used are ASTM F1929- Dye Penetrant and F2096-Bubble Leak. Both methods were established using Tyvek® as a porous packaging material and are generally recognized as consensus standards by the FDA. They are additionally listed in ISO 11607 as ways to show compliance to the standard.

In the case of a Tyvek to Tyvek coated pouch the use of the dye penetrant test is not recommended for two reasons: the dye solution readily penetrates Tyvek® causing false failures and the pouch configuration does not have a transparent side to visually detect a channel in the seal. The ASTM F2096 Bubble Leak test then becomes a default method of choice because it does not require transparency in the package.

The acceptance criterion for a bubble leak test is no constant stream of bubbles, which is an indication of a specific area of failure like a channel. With Tyvek® caution needs to be taken when evaluating the nature of a seal failure. As a slow forming bubble in the seal is often an indication of air penetration through the profile of Tyvek® and not a channel in the seal.

Finally, when using ASTM F2096 bubble leak test for the first time in an application it is helpful in generally understanding it and its applicability by creating a known defect control sample. This is not only essential for determining the correct pressure, but also for establishing the sensitivity of the test. One way of accomplishing this, is by sealing a fine wire in one seal of a pouch and after it has cooled remove the wire. For this test method be sure not to use a wire diameter smaller than 250_m.