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Container Closure Integrity Testing (CCIT) is essential for maintaining the sterility and stability of sterile injectable products. The optimal test method varies depending on the product. CCI testing is used to determine if there is a leak between the contents of a container and its external environment. This can be done by identifying whether communication can be established between the contents of the container and its surroundings.

Pharmaceutical containers such as vials, syringes, cartridges, and blister packs are frequently tested as part of a stability study to ensure that the closure of the container can maintain a sterile barrier. As part of a stability testing methodology, the Food and Drug Administration (FDA) suggests performing a container closure integrity test instead of a sterility test. Primary packaging methods based on vials for sterile pharmaceutical products must provide protection over the shelf life. This necessitates the demonstration of Container Closure Integrity (CCI), which should be done early in the pharma product development process. Helium leak testing is the most chosen CCI test method due to its high sensitivity when compared to other leak test methods.

What is Helium Leak Testing and How it Evaluates Vial Integrity?

Helium leak testing is one of the Container Closure Integrity (CCI) test methods for testing the leakage of pharmaceuticals and medical devices. This method uses helium and the change in concentration is detected when it exits owing to leakage. The applications of helium leak testing include vials, pre-filled syringes, foil pouches, or cold form blister cards. Each of these packaging types is meant to keep out harmful environmental pollutants such as dirt, microorganisms, or even gases while maintaining the sterility of the medicinal product enclosed. The package is filled with helium and subjected to vacuum in this method. A helium leak detector is used to quantify the amount of helium that escapes the package. The result is expressed as a leak rate.

Why Use Helium as a Tracer Gas?

Due to the following reasons, helium is considered an ideal choice for this type of testing:

• Helium is inert, and it is one of the smallest gas molecules.
• Small atomic size allows it to breach pathways reliably and easily.
• Helium is non-toxic, non-condensable, non-flammable.
• Safe to use as it will not interact with the components being tested.
• Helium is less expensive and readily available when compared to other tracer gases.
• The presence of helium in the atmosphere is not more than 5ppm.

As a highly sensitive quantitative test technique, helium leak testing evaluates Container Closure System (CCS) components for parenteral applications. It offers quantitative leak rate data that significantly exceeds the detection limitations of conventional approaches. The method has proven to analyze the impact of processing factors on container closure systems, such as parenteral vial capping applications, elastomeric closure selection, or changing sealing parameters.

The use of pre-filled syringes (PFS) as a container solution for pharmaceutical products has increased significantly in recent years. It is expected that this trend will accelerate in the future decades. Pre-filled syringes have the benefit of reducing pharmaceutical waste and extending the life of the product for the pharmaceutical industry. In general, pre-filled syringes are recognized as an effective, reliable, and convenient way to dispense drugs. In addition, many injections can be self-administered without worrying about being completely transferred from a vial. It provides a safe and effective option for patients in need of long-term pharmaceutical therapies.

When compared to the conventional vial, pre-filled syringes provide extra complexity in the field of container closure integrity (CCI) inspection. The advantages of pre-filled syringes include ease of use compared to conventional vial packaging. Pre-filled syringes eliminate the necessary procedures before you use the drug in a vial. In addition, since pre-filled syringes contain the correct dose, it helps to avoid dosing errors.

Leak Testing Pre-Filled Syringes Using Helium Mass Spectrometry

The device that detects and monitors leaks within and outside a product is called Mass Spectrometer Leak Detector. This approach makes use of helium as a tracer gas, which is utilized to fill a product coupled to a detector. Helium mass spectrometry is widely known for its suitability for non-porous packaging like vials and pre-filled syringes.

The leak detector works on the basis of a sector field mass spectrometer. In a vacuum, analyzed entering gases (Helium) are ionized. Helium ions are accelerated and separated in a magnetic field using increased voltage. Using a specific detector, the ion current is converted to an electric current. The current is accelerated and displayed on the screen by leak detection units. The current measured is proportional to both, the helium concentration and the measured leakage.

Benefits of Helium Leak Testing

• Leaks may be detected and quantified with a high degree of sensitivity.
• Due to the inert properties of helium, it does not affect the substances under test.
• The testing is mostly conducted in a dry, temperature-independent environment.
• Helium leak testing has a shorter cycle time, which lowers the cost and overall processing time.

For non-porous packaging including vials, pre-filled syringes, and cartridges, helium mass spectrometry has emerged as the new leak detection standard. Unlike probabilistic traditional methods, helium leak detection methods are preferred by manufacturers and regulators for their high sensitivity, fast test time, and detection capability. Pharmaceutical industries usually choose this process during the evaluation and eligibility stages of a new packaging process, where MALL plays an important role.

Foil pouches are commonly used when a product requires multi-layered packaging. They are utilized as the innermost layers of packaging. Since the foil pouches come into direct contact with the packaged product, they must be of the highest quality and extremely hygienic. They are typically composed of aluminum and are used to protect products from high temperatures. Furthermore, foil pouches have a low moisture vapor transfer rate. Foil pouches usually contain three to four layers. The higher the number of layers, the higher the pouch quality. Each extra layer increases the strength of the pouch.

Foil pouch integrity testing offers a unique set of challenges. The occurrence of foil punctures is an issue in most packaging techniques that use foil as the product barrier. These imperfections can occur when the foil is rolled into thin sheets and microscopic particles are rolled into the foil by mistake. Handling of the packages during the assembly of the foil and insertion of the drug product is the most typical source of the defect. Although the human eye can only reliably spot punctures bigger than 100 µm, these faults are difficult to identify. Punctures smaller than this can cause substantial ingress and, as a result, affect the effectiveness of the product.

How to Inspect Foil Pouches for Quality Control Using Helium Leak Test?

A highly sensitive method of detecting leaks in enclosed systems by using helium as a "tracer gas" is known as helium leak testing. Pre-filled syringes, foil pouches, and cold form blister cards are the most common applications of helium leak testing. Each of these package types is meant to keep out harmful environmental pollutants including debris, germs, and even gases while maintaining the sterility of the drug product inside. The leak rate is calculated from the amount of helium that escapes from the package.

The sensitivity of the helium leak detection methods makes it an ideal platform for quality control testing foil-based packaging systems. The test technique is designed to identify helium that has been trapped in the packaging system and has leaked via micro-voids in the pouch. Placing the foil pouch in the custom-designed test fixture and drawing a vacuum is the first step in a test sequence. Helium thus escapes through possible defects in the package as a result of the resultant pressure difference. The flow is directed to the analyzer cell at vacuum pressure, where the escaping helium gas is measured in the cell.

The average test cycle time is between 20 and 60 seconds. The test chamber is evacuated to the environment when the test cycle is completed and the measurement is recorded, and a new sample can be tested. The LDA HSAM helium concentration device is used to detect the helium concentration value of each pouch once all samples in the designated set have been tested. This approach normalizes the helium leak rate to 100%, allowing direct comparison of all test samples as well as the manufacturing line configuration.

Helium leak testing, one of the most commonly used CCI testing methods, is used to accurately determine the tiniest of the leaky opening in the foil pouches. Using this method, leaks can be quantified and detected with a high level of sensitivity and quality control testing. The Food and Drug Administration- FDA has long recognized helium leak detection as a consensus standard for package integrity evaluation.

Maintaining the integrity of products from the time it is manufactured to the time it is distributed to the patient is a great challenge. Liquid pharmaceuticals, capsules, and formed tablets are typically packaged in bottles. To assure the quality of these items, leak testing is carried out on each bottle to ensure that it does not leak. Testing pharmaceutical bottles or pharmaceutical package leak detection before filling is a critical step in ensuring the integrity of the container.

Helium leak testing is one of the most sensitive Container Closure Integrity (CCI) testing techniques that can be applied to pharmaceutical bottles for testing quality. Helium is used as a tracer gas, and the quantity of helium leaving through the package is measured and stated as leak rate. Since it is non-toxic, non-flammable, and non-condensable, helium is an ideal tracer gas for finding leaks. Its atmospheric presence is restricted to 5ppm. Due to its tiny atomic size, helium can easily pass-through leaks. Helium is also safe to use since it does not react with the materials of the components under test.

Significance of Helium Mass Spectrometry in Leak Testing Pharmaceutical Bottles

Helium mass spectrometry is a leak detection standard for pharmaceutical containers including bottles. Helium mass spectrometer, a commonly used instrument detects and locates tiny leaks. It usually works with a vacuum chamber and a sealed container filled with helium. A mass spectrometer detects the rate at which helium is leaking out of the container. This method uses tracer gas - helium to fill the product attached to the detector. The tested product leaks helium into the detector, where its partial pressure is measured and displayed.

The leak detector's principle is based on a sector field mass spectrometer. In vacuum, entering helium gases are ionized. The helium ions are then accelerated by adding voltage and then separated in a magnetic field. The ion current is converted to an electric current by using a particular detector. This current is accelerated using leak detection units and displayed on the screen. The current measured will be directly proportional to the concentration of helium and therefore equal to the leak measured.

Applications of Helium Leak Detection

• Ensure container closure integrity.
• Seal integrity monitoring during stability studies.
• Verify and predict shelf-life seal integrity.
• Useful in the early stages of the development of a pharmaceutical product packaging system.
• Closure formulation and configuration selection.

Bottles are useful in the healthcare industry, hence evaluating them is a challenging task nowadays. These containers are extremely difficult to test, however, helium leak detection can be used to qualify them prior to use or as a proof of concept. LDA provides professional engineering solutions for the Active Pharmaceutical Ingredient (API) sterile container testing.