How Are Low-Headspace Packages Tested for Leaks?

Low-headspace packages are typically flexible or semi-flexible package formats with minimal air. The minimal headspace makes them more vulnerable to the impact of a leak, creating more rapid impact to the headspace concentration. Detecting leaks can be challenging because there is also less headspace to measure any leakage. Deterministic methods like Vacuum Decay or Force Decay identify micro-leaks in these containers by measuring subtle pressure deviations. Helium leak detection can also be used to ensure that the smallest leaks, and even failures in the oxygen barrier package layers, can be detected. These systems ensure that even packages with nearly 100% liquid fill maintain their sterile barrier.

What Is CCIT for Low-Headspace Containers?

Container Closure Integrity Testing (CCIT) for low-headspace packages involves measuring the physical integrity of the package barrier. Because low headspace amplifies the impact of a leak, small defects must be detected. Leaks in the single-digit micron range can be defected using these deterministic methods. Ultimately, any low headspace package with a foil barrier must be tested for micro leaks. All leaks are critical for these package formats, but larger leaks can be elusive because all the headspace leaks before anything reasonable is measure.

How Does Vacuum Decay Work for Low-Headspace?

Vacuum Decay is recognized under ASTM F2338 and referenced in USP <1207> as a deterministic test method. In low-headspace applications, the system creates a vacuum around the package and monitors for a pressure deviation. Vacuum decay is often paired with a force decay measurement to ensure the package does not have any larger defects by confirming the expansion of the package. Without large leak confirmation, all measurable leaks can bleed air before the system registers the leak. Force decay allows the system to identify leaks even when there is no air to leak out.

What Regulatory Standards Apply to Low-Headspace Testing?

USP <1207> defines expectations for deterministic CCIT and method validation. It explicitly advocates for quantitative results over subjective dye tests for high-risk low-headspace products. Standard regulatory environments insist on applying quality risk management principles. Low headspace package formats introduce additional risk due to the rapid change a small leak can cause.

ASTM F2338 provides the protocol for vacuum decay testing in pharmaceutical packaging. Systems must also comply with 21 CFR Part 11 to ensure all electronic test records are secure and traceable.

What Is the Application of Low-Headspace Testing?

This testing is critical for man transdermal products, semi-flexible cold-form blister packaging, and other flexible formats. It ensures that the product remains sterile and that environmental contaminants such as moisture or oxygen do not degrade critical product attributes.

• Transdermal Patches: With almost no headspace the formats can be extremely sensitive. Due to the extremely low headspace even cracks in the foil barrier along the seal create oxygen transmission points, which Helium can detect. Force decay is also effective to measure the expansion of the transdermal package.
• Cold-form blister packs: The aluminium barrier indicates oxygen or moisture critical nature. The semi-flexible surface offers ideal force decay measurement.

Frequently Asked Questions

1. Can Vacuum Decay detect leaks in 100% filled containers (i.e. no gas)?

Yes, deep vacuum can drive the liquid to phase change and the same vacuum and force decay method can be applied. Often times force decay is not necessary because the liquid produces enough gas induced from phase change during the test cycle.

2. Is the test destructive for low-headspace containers?

No, Vacuum Decay and force decay are non-destructive methods that preserves the sample and its contents for use.