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Testing the integrity of blister packages is essential to guarantee that the packaging safeguards the contents from oxygen, moisture or contaminants. Packaging keeps the product safe and functional by preventing air ingress.

Probabilistic test methodologies have been widely used to conduct blister package integrity tests, such as the blue dye test method. These tests rely on a range of sequential or simultaneous events, each with random results that are characterized by probability distributions. In order to acquire relevant results, it is necessary to use large sample sizes and strict test condition controls because the findings are related to uncertainty. Studies have also revealed the unreliability of such testing, which frequently fails to detect leaks that could endanger the quality of a product.

As a result, it is preferable that the integrity test method be deterministic. The leakage event being detected or measured in this type of test method is based on phenomena that follow a predictable chain of events. Helium leak detection is an example of a deterministic, highly sensitive method.

What is Helium Leak Detection Technology?

Helium Leak Detection Technology is a Container Closure Integrity test (CCIT) method found to be highly effective in evaluating the integrity of a wide range of complex pharmaceutical and parenteral products. Helium leak detection can be understood as the process of identifying leaks in any closed or sealed system with the help of helium gas and measuring its concentration as it escapes due to leakage. Common applications of helium leak testing include pre-filled syringes, cold form blister packs, foil pouches and many other package formats. The technique uses helium as a tracer gas and its concentration is measured as it escapes through the leaks. Under this method, the package is helium filled and subjected to vacuum. The amount of helium escaping the package is quantitatively measured and stated as a leak rate.

Why is Helium used as a Tracer Gas?

Helium is used as a tracer gas because of certain unique qualities that make it ideal for leak testing.

• Non-toxic, non-condensable, non-flammable.
• Helium gas is inert, which means it does not interact with the components being tested.
• Since the atomic size of helium is small, it can easily breach through 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 5ppm.

Technology Overview

The procedure begins with filling the package with helium, after which vacuum is applied within a chamber. The amount of helium escaping from the package is then quantified using a helium leak detector. This is then referred to as the leak rate. Helium leak detection technology is also suitable for package design, failure analysis, tooling qualification, packaging line setup and validation, and product quality monitoring, in addition to leak testing. ASTM F2391 helium leak detection is a well-established method recognized and widely used in the pharmaceutical industry.

Applications of Helium Leak Testing

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