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Like vials package systems, bottles whether composed of plastic materials or glass, continue to be one of the most widely used package systems and Helium remains the gold standard for quality testing purposes.

Evaluating seal integrity of bottles or containers used for liquid contents is what ensures the quality of the bottles surpass the quality parameters. Seal integrity testing of bottles is done to ensure that the contents of the container do not leak out in any condition. As weak seals, partial seals or no seals can occur in the final sealing stage, manufacturers often conduct high-quality seal integrity tests that guarantee reliability and quality of bottle seals.

Thread shape, mating surface shape, and composition of the material used for making the container and the closure are common factors that can affect the seal integrity of bottles. An ideal seal can be generated if the container and closure materials are made up of distinct composition. Seal quality can also be affected by time-dependent factors. This is especially possible if containers, closures, or both are constructed using plastic resins. Similarly, exposing the bottle and its contents to freezing temperatures can affect the seal via expansion and contraction of the materials in threads and mating surface area.

Before dispatching, leak detection of sealed containers is a crucial vital step to ensure container’s seal integrity, food and nutrition, medical device and pharmaceutical industries require highly sensitive leak testing techniques to measure seal strength of the containers. One such method is helium leak detection.

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.

Over the past decades, there has been steady stream of advances over combination products and a deepening trend towards self-care. This is because combination products offer a safe and convenient method of operating drug or biologic therapies. Medical devices that can be self-administered are increasingly being used to shorten procedure time and reduce the chance for practitioner errors.A combination product is a mixture of a drug and device that includes pre-filled syringes, insulin injector pens, transdermal patches, and catheters with antimicrobial coatings. These are often termed as high-risk devices in the life science industry. As such, devices they require in-depth testing and evaluation.

The risk associated with combination products depend on the likelihood of interaction between the package and the drug, as well as the level of risk associated with the administration route. For many drug-device combination products, inhalations and injections are specified as high-risk routes of administration. Hence, evaluating seal integrity of combination products is extremely critical. Due to inadequate sealing, there is a chance for water vapor or oxygen to enter the package through a permeable surface. In such cases, surfaces and seals may need to be tested depending on the nature of the products. Also, there is a need to evaluate the packaging components and dosage, ignoring which, could cause serious health risk to the patient.

Importance of Helium Mass Spectrometer Leak Detector in Combination Products

The Mass Spectrometer Leak Detector is a system used for localization and measuring leaks inside or outside a product. This method uses tracer gas – helium, which is used to fill up the product connected to a detector. It is well documented that helium mass spectrometry is most suited for non-porous packaging such as vials and syringes. The same methodology can also be applied to cartridge-based delivery systems. In most cases, the key to success is developing a text fixture device, designed and manufactured to cater to the needs of specific cartridge system being tested.

Applications of helium leak testing.

Following are the applications of helium leak testing:

• Ensuring Container Closure Integrity
• Closure formulation and configuration
• Seal integrity monitoring during stability studies
• Extremely valuable in early-stage pharmaceutical product package system development

Pharmaceutical product manufacturers use packaging materials that offer optimal protection and safety allowing to extend product shelf life. Cold form blister packs are manufactured by sandwiching aluminum foil between Polyvinyl Chloride and nylon films using dry bond lamination technology. They provide complete barrier to moisture, light, oxygen, and other gasses. Its ability to offer complete product integrity and protection has made it a favourable choice for pharmaceutical industry.

Oral and solid dose manufacturers aim at producing high quality and cost effective alternatives while manufacturing innovative, convenient packs for end-users. Due to its high efficiency rate and the ability to provide extended shelf life, the cold form blister packs are being extensively used in healthcare packaging. Many pharmaceutical products including tablets, capsules, drugs, vials, ampoules, syringes or liquid products are often packaged using cold form blister packaging. Infact, growing requirements of pharmaceutical companies worldwide had led to the production of cold form foils such as push-through, peelable, peel-push, tear-open and child-resistant. However, the growing demand for cold form blister packs have accelerated concerns about integrity of blister packaging. Although the amount of environmental contaminants that can enter a package vary based on leak size, with blister packages, even minute leaks can become a problem. Depending on the pressure, temperature and duration of exposure, contaminants can easily find path in the seal or any other microscopic crack. Therefore, it’s important for manufacturers to conduct appropriate container closure integrity tests that ensure quantitative and reliable leak testing solution.

Helium leak testing is one of the most sensitive container closure integrity test methods, used primarily for evaluating integrity of critical parenteral or injectable products. In simple terms, it can be understood as the act 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. Apart from being an ideal solution for ensuring container closure integrity, the technology is also applicable in package design, monitoring product quality, failure analysis and line set up and validation.

Helium is considered an ideal choice of tracer gas because of multiple reasons. Helium is non-toxic, non flammable, non-condensable and its presence in the atmosphere is not more than 5ppm. The small atomic size of helium makes it easier to pass through leaks. Since helium does not react with other materials, it is relatively safe to use. Additionally, compared to other tracer gases helium is less expensive and is available in multiple cylinder sizes. Under this method, a helium leak detector otherwise known as Mass Spectrometer Leak Detector (MSLD) is used to identify and calculate size of the leak.The test part is first connected to a leak detector and then the tracer gas, helium is introduced. In the presence of a leak, helium escapes from the test parts and this partial pressure?is?measured and results are displayed on the meter

Applications of Helium Leak testing

• Ensuring Container Closure Integrity
• Using sniffer probe to identify sources of the leak
• Selecting closure formulation and configuration
• Seal integrity monitoring during stability studies
• Using proprietary software to predict shelf- life seal integrity