Headspace Gas Analysis (HGA) is a non-destructive method used to inspect the integrity of pharmaceutical product packaging, accurately examining 100% of products ready to be placed on the market. Headspace Gas Analysis identifies various types of defects and provides useful information on the production process as a whole, making it a particularly effective Container Closure Integrity Test (CCIT) method.
What is Headspace Gas Analysis?
Headspace Gas Analysis is an inspection method that determines the concentration of certain molecules inside a sealed container.
HGA uses laser absorption spectroscopy (TDLAS) to analyse the headspace (i.e., the space inside a sealed container that is not occupied by the product itself) inside the sample. The sample to be inspected is crossed by a laser beam tuned to the frequency of the specific molecule whose concentration is to be determined. Then, the amount of laser light absorbed by the gas in the headspace is detected. If absorption is greater than anticipated, this means that the concentration of the molecule is higher than that expected for the process and therefore higher than the limit set for acceptance. So, the product could be damaged, improperly sealed, punctured or contaminated.
HGA can be used to measure the presence of different types of molecules, such as:
- Water vapour, which can damage lyophilised and hygroscopic products, as water molecules are absorbed inside the packaging over time
- Oxygen, which can cause oxidization, change the product’s taste and smell, and, in the case of pharmaceutical products, damage the active ingredient
- Carbon dioxide, the presence of which may indicate that the product has been contaminated by bacteria and that fermentation is in progress
The advantages of Headspace Gas Analysis
As stated, Headspace Gas Analysis is one of the inspection methods that can be used for Container Closure Integrity Testing (CCIT). It offers many advantages, and can be used:
- To accurately and reliably inspect 100% of products without destroying any samples, so that all products passing the inspection can be used
- To conduct tests on high-speed lines, because very little time is required to perform the inspection
- To collect data to assess production effectiveness, since excessively high numbers of failing products or an increase in the percentage of rejects can indicate various problems on the production line. By correctly interpreting the data obtained from HGA, these issues can be identified early on, and action can be taken quickly to resolve them.
When should Headspace Gas Analysis be used?
Headspace Gas Analysis can be effective in monitoring the production process and for CCIT. While this type of inspection can be very beneficial, many factors need to be carefully evaluated when designing an HGA system. Here are some of the things to consider during the design phase:
- The ideal composition of the product's headspace: As we have seen, HGA establishes the concentration of a given molecule inside the product's headspace. So, for the inspection to be effective, we first need to know the ideal composition of the headspace’s atmosphere, and then establish the threshold value beyond which the concentration of a given molecule could be harmful to the content.
- Possibility to inspect pharmaceuticals after quarantine: HGA’s accuracy in identifying damaged products increases if the samples to be inspected are quarantined for a period of time before being inspected. Over time, exposure to atmospheric factors can amplify the impacts of possible defects like micro-holes in the packaging, improper seals, and so on.
- Packaging type: HGA is effective for inspecting many types of packaging, since lasers can be used to examine glass or plastic containers of various shapes, diameters and colours with different fill levels. However, all of these parameters must be considered during the design and sizing phases of the machine used for testing.
- Product type: Different types of product require different types of HGA inspections. For example, it would be ineffective to determine the percentage of water vapour inside packaging for liquids, because evaporation could falsify the concentrations detected by the laser. For products of this kind, it is useful to detect the amount of oxygen in the headspace, provided the product itself does not oxidize too quickly, which could distort the inspection, and so on. We must carefully consider all of these aspects to determine which molecules should be sought using HGA, to ensure that inspection is truly effective.
Headspace Gas Analysis is a safe and effective CCIT method used to inspect a wide range of products and packaging types. However, in order to ensure that this type of test meets expectations, the characteristics of the production line and of the products to be inspected must first be thoroughly analyzed to ensure that the HGA system is designed appropriately. This is where an experienced and competent partner like Bonfiglioli Engineering can provide critical support.
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