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Container closure integrity plays an integral role in maintaining the stability of sterile pharmaceutical products. Most often, defects that cause vials to leak cannot be detected by a visual inspection process. Examples of such defects include microscopic cracks & scratches in the glass or temporary defects such as stopper pop-up that result in temporary container leakage. In such situations, helium leak testing ensures high sensitivity leak detection, which cannot be attained by many other leak test methods.

Overview of helium leak testing

Helium leak testing refers to the process of finding leaks in some type of enclosed or sealed system using helium as a “tracer” gas and measuring its concentration as it escapes due to leakage. It is an effective container closure integrity test method, aimed at evaluating the integrity of pharmaceutical and parenteral products. Helium leak detection works in the following way: Initially, the package is helium filled and subjected to vacuum. Then using a helium leak detector, the amount of helium escaping the package is quantitatively measured and stated as a leak rate. Apart from analyzing container closure integrity, helium leak testing is also applicable in product design, product quality analyses, failure analyses and validation. Helium leak testing is a flexible method that can be used with or without a test chamber in order to test "in-leakage" or "out-leakage", as well as leak location.

Why use helium as a tracer gas?

Helium is considered as an ideal choice of tracer gas because of the following reasons:

• Helium is non-toxic, non-condensable, non-flammable.
• It is inert, making it safe for use as it will not interact with the components being tested.
• The atom size of helium is really small, allowing it to breach pathways reliably and easily.
• Compared to other tracer gases, helium is less expensive and readily available.
• Its presence in the atmosphere is not more than ppm.

Glass vial leak testing using SIMS 1915+

Seal Integrity Monitoring System (SIMS) 1915+ is an ideal choice for helium-based leak detection of vials, blister cards, syringes, and cartridge systems. Compared to conventional vacuum bubble and dye penetration test methods, packages can be quantitatively tested using helium as the tracer gas that ensures higher levels of accuracy. Proven to be an affective leak detection method, SIMS1915+ can also be used for package design, tooling qualification, production line setup and on-going product quality monitoring. Designed specifically for the needs of pharmaceutical and medical device industries, SIMS1915+features an oil-free pump, detector and integrated power system that ensures quantitative analysis of package systems at sensitivity levels as low as 1 x 10 -10 cc/s at room temperature. Based on the client’s specific requirement, each SIMS 1915+ Helium Leak Testing instrument manufactured by Leak Detection Associates can be customized. Given below is a list of SIMS 1915+ Leak Detection System specifications along with add-on components.

• Helium Leak Detector Module (HLDM): Oil Free, Production version in Console Frame Assembly, with Stainless Steel working surface and Dual Test Port Manifold (allows concurrent use of VTFM & HSAM on HLDM unit).
• Vacuum Test Fixture Model (VTFM) – custom designed for use in testing of vial container samples
• Head Space Analyzer Module (HSAM) – Model VM-2 that includes three (3) Puncture Probes (two spares) for determination of Helium Concentration in the headspace of vial containers.
• Integral Calibration Chamber (w/ Calibrant Gas Flow Meter/Controller) provided for HSAM Calibration and a Universal Holder to be used for various vial diameters.
• Helium Filling Device specific for vial testing sample prep to enable vials to be filled with helium
• LT Low Temperature Add on units specifically designed for testing products under ultra-cold storage testing down to –140 °C.