Nov 2021

Integrity Testing of Seals Using Tracer Gas - Helium


Using helium as a tracer gas is the most sensitive and commonly used tracer gas leak detection technique for CCI. When moisture-sensitive pharmaceutical products are lyophilized, their shelf life is extended, and they are better prepared for storage and transportation. A lyophilized medicinal product's quality is ensured by maintaining consistent moisture content. Proper container closure system (vial, stopper, seal) selection and sealing conditions are equally important factors. Demonstrating Container Closure Integrity (CCI) is one way of achieving this goal.

Why use helium?

Helium gas is one of the smallest molecules. In addition to being non-flammable, non-destructive, non-toxic, and inert, helium only has a trace presence in the atmosphere. Helium is generally safe to employ (compared to hydrogen) since it will not react with any of the components in the test part. Mass spectrometers detect helium in the vast majority of leak testing applications. A residual gas analyzer, on the other hand, is also an option. In general, helium leak testing ensures higher levels of sensitivity than conventional pressure decay methods.

Tracer gas method to test seal integrity

Tracer gas leak testing is a simple and very effective way of detecting leaks that offer great sensitivity, accuracy, and repeatable results. Being one of the most effective method of leak detection, tracer gas leak testing offers great sensitivity and accuracy. Micro-leaks between 1x10-4 to 10-9 scc/s can be detected using the tracer gas leak test, which utilizes the tracer gas - helium. Tracer gas leak testing can be done with either pure helium or by mixing it with another gas such as nitrogen or dry air to reduce the overall cost. A mass spectrometer is used in the standard test method for measuring package and seal integrity. Due to its low concentration in the atmosphere, and its detection using a mass spectrometer, helium is employed. It is done by injecting helium into sealed packages or adding it to sealed package’s headspace after sealing. In the following step, a mass spectrometer is used to identify and measure the presence of helium in the surrounding enclosed space.

Vacuum test method is the commonly employed tracer gas method for testing the seal integrity of pharmaceuticals products. In this method, seals are put under stress by a vacuum, which measures tiny leaks. Helium transfer rate captures the real transmission rate through the material as well as via the seals. Transmission of helium through the material as well as seals is captured by helium transmission rate. As a result, the vacuum technique is more effective in detecting leaks since it monitors helium gain in the external environment within the enclosed sample.

When packaging seals are tested for integrity, it helps guarantee that the packaging offers necessary product protection for patient safety. To ensure product quality, package seals must be reliable. Seal integrity tests are commonly used to evaluate sustainable packaging options, lower-cost packaging, and changes in manufacturing line sealing parameters, among others. Evaluating the seal strength of packing materials with reduced costs and alternative sealing procedures confirms that the seals do not leak over time.

Leak Detection Associates (LDA) designs and manufactures high-performance tracer gas (helium) leak detection systems to ensure the integrity of seals for the pharmaceutical and biological industries. Helium leak detection is the one of the most effective leak detection method to identify and locate leaks in a closed system.

helium leak testing, mass spectrometer, helium mass spectrometry, mass spectrometry, helium detector
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