Many industries have used high-sensitivity leak detection using helium mass spectrometry for years. When it comes to packaging system qualification, the USP <1207> Package Integrity Evaluation for Sterile Products gives an overview of relevant and appropriate test techniques that may be used. Understanding these approaches on a basic level can help you make a more intelligent decision about the most effective test methodology for your unique container and package system.
Pharmaceutical and medical device industries are among the industries that utilize helium leak detection. Helium leak detection is utilized in the life sciences sector for a variety of purposes, from leak testing of process or production equipment, as it was initially employed in the 1940s, to testing of sealed containers or hermetically sealed devices. Using helium as a tracer gas this technique is outlined in an ASTM standard, ASTM F2391–05 (2011) for evaluating package and seal integrity.
Working principle of USP<1207> Helium Leak Detection
Helium leak detectors use a vacuum circuit, which includes a mass spectrometer, which consists of a number of pumps and internal valves. Vacuum is drawn from within by internal pumps, which can be attached to a variety of things, such as sniffer probes or test chambers holding equipment to be evaluated. An analyzer cell monitors the helium leak rate bypassing the escaping or traveling gas through an analyzer cell. In general, helium leak detectors follow this principle, regardless of their design or use. Using helium leak detection, test procedures may be customized by adjusting test sample preparation and the vacuum circuit’s connection.
Applications and limitations of USP<1207> Helium Leak Detection
The advantages and disadvantages of helium may differ significantly depending on the method used. However, helium leak detection as a test methodology has certain similar aspects. Helium leak testing is both selective and sensitive since it measures just helium, down to very low leakage rates with no influence from other atmospheric gases or moisture in the environment. In addition, helium leak detectors can be used in a variety of ways, with a variety of connections, fixtures, chambers, and probes, within the limits. These include helium permeation through porous materials and a preference for empty samples in an effort to prevent leak path blockage.
This is why helium leak detection is not a single solution for all tests, yet it is an essential tool in package development, and it is commonly included in comprehensive container closure integrity (CCI) control techniques. In addition, its high sensitivity allows for testing up to the maximum acceptable leakage limit of most goods, as well as leak testing at -80°C or lower, such as liquid nitrogen deep storage and vapor phase.
