Abstract:
The integrity testing of sterilization systems mainly involves visual inspection, dye penetration testing, bubble testing, etc., to verify the leakage of packaging. In domestic medical packaging registration application materials, the integrity testing items for packaging include dye penetration method for determining the sealing leakage test of breathable packaging, visual inspection, and bubble method for determining leakage test of flexible packaging; packaging strength testing items include sealing strength test of flexible barrier materials, unconstrained packaging resistance to internal pressure destruction test, and simulated transportation test, etc.
This article first introduces the detection of gross leakage by internal pressure method (bubble method) and the detection of packaging leakage by vacuum method (negative pressure).
Detection of Gross Leakage by Internal Pressure Method (Bubble Method) (Positive Pressure)
Standard：ASTM F2096
This experiment is used to determine whether the packaging, when inflated underwater to a predetermined pressure, exhibits a stable flow of bubbles indicating failure areas. The test method can be used for tray and pouch packaging, with a detection probability of 81% for packaging with apertures of 250μm or larger. The sensitivity of the method depends on the pressure difference, and the method for pressure calculation is crucial for obtaining reproducible results, determining the test pressure for each packaging material/size. Insufficient pressurization can significantly reduce the sensitivity of this test method. The greater the pressure difference, the higher the test sensitivity. However, excessive pressurization of the packaging may lead to seal rupture or misinterpretation of the bubble pattern for porous packaging... These may lead to erroneous conclusions about the presence of packaging defects. While not required, the use of emission control valves that comply with pressure monitoring devices will help stabilize the test pressure and eliminate excessive pressurization of the packaging.
Increasing the pressure difference during testing will enhance test sensitivity, but excessive pressure difference can cause seal cracking. Therefore, it is necessary to quickly apply pressure at the beginning of the test, and then slowly apply pressure in the latter half until a stable and continuous stream of bubbles appears. After determining the test pressure, testing other samples can also be done by gradually reaching the test pressure with a fast initial increase followed by a slow increase. For breathable packaging, testing should be conducted after the barrier agent has dried. This test has minimal restrictions on packaging size and is particularly suitable for packaging with variable and irregular sizes, such as oversized or undersized packaging.
Does the breathable material require the application of a barrier agent?
If the test pressure > the point of breathability, barrier agent is applicable, otherwise, it doesn’t need the barrier agent.
Vacuum Method for Detecting Packaging Leakage (Negative Pressure)
Standard：ASTM D3078
Submerge the test sample in a container filled with liquid placed inside a vacuum container. Set the vacuum level and duration according to the packaging characteristics, selecting low, medium, or high vacuum levels based on the packaging. The higher the vacuum level, the smaller the detectable aperture. As the vacuum level increases, observe whether continuous bubbles appear in the packaging or if there is liquid ingress into the packaging. If either of these phenomena occurs, the sample leaks. Individual bubbles caused by trapped air do not constitute leakage. Additionally, note the approximate increase in packaging volume. The increase in sample volume is inversely related to the test pressure, with larger volumes significantly reducing test accuracy. The reliability of this test method is diminished when used with flexible packaging that has top space or no top space.
Introduction to Integrity Testing Equipment and Laboratory
Labthink provides two models that can conduct these integrity testing with the mentioned method: one is C660B Bubble Emission Leak Tester (ASTM D3078) and another C660M Leak and Seal Strength Tester (ASTM F2096). Labthink also have a professional laboratory to process these tests with CANS certificate. For more information, please visit https://en.labthink.com/en-us/products/test-property/leak-tester.html or send us email directly via info@labthink.com .