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Several leak detection methods, that are deterministic and non-destructive, are already available in the market. Pharmaceutical companies are urged to use technologies that significantly enhances quality assurance and leak detection rates. Appropriate leak detection technology is selected based on the specific characteristics of the product and container, such as conductivity, headspace parameters, contents, or API. Historically, dye immersion and microbial immersion have been the two main methods of vial integrity testing. Recently, the USP has issued guidelines that require critical methods to achieve more reproducible and predictable outcomes. USP <1207> encourages a move towards more deterministic methods, recommending the avoidance of dye immersion tests and the use of quantitative, non-destructive technologies instead.

Why High Voltage Leak Detection Method is Preferred for Testing Vials?

High Voltage Leak Detection or HVLD is a deterministic, non-destructive leak detection method to evaluate vials, cartridges, and other liquid-filled parenteral products for Container Closure Integrity. The current generation of PTI’s MicroCurrent HVLD may be utilized with a wide range of liquid-based products, from low conductivity sterile water for injection to highly proteinaceous drug preparations in suspensions. It is one of the most effective online container closure testing methods, requiring just minor infrastructure modifications. When compared to conventional HVLD solutions, MicroCurrent HVLD utilizes approximately 50% less voltage and exposes the product and environment to less than 5% of the voltage. This method is non-invasive and requires no sample preparation. Like vial leak testing, another major application of MicroCurrent HVLD is pre-filled syringe testing.

Working Principle of MicroCurrent HVLD Technology

In this method, the container is scanned using a set of high voltage electrode probes. A high voltage is applied to one side of the container, while a ground probe is attached to the other. If there is no leak in the package, the two container walls (high voltage side and ground side) offer complete electrical resistance, and no substantial current is measured flowing through the vial. If a micro-leak or fracture occurs in one of the container walls, the break-down resistance is achieved, and the current flows through. HVLD is the only leak detection method that does not require mass to travel through a defect location, instead of requiring just electricity to pass through a crack. Because of this feature, HVLD is sensitive to leaks that conventional leak detection technologies are unable to detect.

MicroCurrent HVLD Technology Advantages

• Deterministic and non-destructive test method.
• High level of repeatability and accuracy.
• Ensure more accuracy and dependability in results.
• At high production rates, both offline and 100% online inspections are performed.
• Simplifies the inspection and validation procedure.
• Highly effective in all parenteral preparations, even liquids with extremely low conductivity (WFI).
• Outlined in the USP 1207 Guideline.

Pharmaceutical containers like vials protect the product from contamination (sterile barrier) and prevent changes in product quality caused by external factors. In order to determine the functionality of such systems, container closure integrity testing is performed. CCIT provides sophisticated analytical methods for evaluating pharmaceutical containers.

Prior to commercialization, the development of new pharmaceuticals, particularly combination treatments, was a complicated process involving extensive research. When it comes to packing pharmaceuticals for patient use, several things must be considered to ensure that they satisfy the highest quality requirements and are safe to use.

Nowadays, the challenge of adopting traditional glass or specialized polymers as combination products has become common. Similarly, the demand for scientific evidence to support regulatory requirements for the pharmaceutical industry has also become more prevalent. For effective development and commercialization of a pharmaceutical product, it is important to understand the compatibility and performance of the primary packaging system with both, the pharmaceutical product and the delivery systems, regardless of the material.

Container Closure Integrity (CCI)

Container closure integrity (CCI) testing is important when ensuring the quality of all packaged products, especially when it comes to parenteral drugs. To evaluate the CCI of the packaging system, a pharmaceutical manufacturer must calculate the Maximum Allowable Leakage Limit (MALL) for the pharmaceutical product. MALL is defined by USP<1207> Package Integrity Evaluation – Sterile Products as the highest leak rate that may be tolerated for a specific packaging method while posing no harm to the safety and quality of the pharmaceutical product over its shelf life. In comparison to probabilistic approaches, USP <1207> provides guidelines on how to assess CCI, including deterministic methods, which are strongly encouraged. Helium leak detection, MicroCurrent HVLD, and Vacuum decay- are deterministic techniques. For the given system, these techniques must be created and validated.

Test methods

MicroCurrent HVLD

MicroCurrent HVLD is a non-destructive technique for determining the integrity of container closures for a variety of parenteral liquid products, including ultra-low conductivity sterile water for injection (WFI). A non-conductive container is examined for pinholes, micro-cracks, plunger leakage, and non-visible crimping leaks, among other things, using an electrode probe. Whenever a defect is identified, it causes a change in current flow and resistance differential, which indicates a breach in the container. The MicroCurrent HVLD is a High Voltage Leak Detection method effective across all parenteral products.

Helium Leak Detection

Helium leak detection is a deterministic method used to detect leaks in pressure vessels and other enclosed systems. In this technique, helium is used as a tracer gas. The change in helium concentration as it escapes through the container is monitored. For helium-based leak detection systems, the Seal Integrity Monitoring System (SIMS) 1915+ is a perfect choice. Helium as a tracer gas delivers excellent levels of quantitative accuracy when compared to traditional vacuum bubble and dye penetration test techniques. Helium is an optimal solution for product quality monitoring across the product lifecycle.

Vacuum Decay

A non-destructive CCI test method for evaluating medical device package integrity. Non-destructive testing improves package quality while decreasing waste when compared to destructive testing. This testing also saves time and money while ensuring product quality. This method operates by enclosing sample packages in a tight-fitting evacuation test chamber with an external vacuum source. A single or dual vacuum transducer is utilized in the test chamber to measure the level of vacuum as well as the change in vacuum over a pre-defined time period. The existence of leaks and defects is indicated by fluctuations in the package's absolute and differential vacuum.

Regardless of the pharmaceutical product, type of materials, devices used, developing a complete testing plan from initial compatibility to stability and release is critical. To assure the availability of scientific data that helps ensure optimal results for patients as well as rapid regulatory approval and delivery to the market, proper testing is required.

High Voltage Leak Detection (HVLD) of pre-filled syringes, vials, cartridges, ampoules, BFS, bottles and liquid filled pouches detects pinholes, micro-cracks, stopper/plunger leaks, non-visible leaks under crimping and many other defects. The HVLD testing procedure also guarantees the security of the product seal by finding tiny pinholes, micro fractures and screen defects that are not visible. Eventual packing defects lead to resistance differential and changes of current flow in the container and the approximate position of the fault. It is also one of the most affordable methods for testing container closure that requires little adjustments to the infrastructure. This technology is not invasive and does not require preparation of the sample. It is one of the most powerful CCI technologies for all biological and parenteral goods

E-Scan HVLD has a high-speed test cycle, produces highly reproducible results and is easy to handle. Fast changeover and easy adjustments of test parameters for various goods and applications are further advantages. Another advantage of the HVLD technique is that it can readily be moved from the laboratory offline to 100% online testing applications at high production speeds. That is an enormous benefit and makes the inspection and validation procedure globally simpler. E-Scan employs a number of electrode probes to scan a sealed container which is not conductive. Glass, plastic or poly laminate might be the container material.

Working principle of MicroCurrent HVLD technology

In non conductive or semi-conductive packing materials, HVLD works by implementing high voltage potential for electrically conductive goods. When electrical discharges between goods and device electrodes are observed, the pinholes are determined. The two container walls (high voltage side and ground side) offer complete electric resistance when the package is not leaked, and no significant current is detected by flash. If one of the container walls has a microleak or fracture, the barrier to breakup is met and the current passes. HVLD is the only technique for leak detection that requires a crack site without mass, needing just the flow of electricity via a crack. This feature sensitises HVLD to leaks that are not identified by typical leak test systems.

Applications of MicroCurrent HVLD

• Pre-filled syringes
• Vials
• Cartridges
• Ampoules
• BFS
• Bottles
• Pouches

Advantages of MicroCurrent HVLD

• High level of repeatability and precision
• Deterministic, non-destructive, non-invasive
• Product and environmental low voltage exposure
• Offline and 100% online testing at high production speeds
• Simpler inspection and validation procedure
• Most powerful CCI technology for all parenteral and biologic products
• Robust method and approximate 3x Signal-Noise-Ratio for a wide range of product classes and package formats