The need to monitor headspace oxygen levels in parenteral containers arises from the requirement to ensure the stability and potency of oxygen-sensitive product. Besides a loss of efficacy and reduction in shelf life, exposure of such products to oxygen can result in product discoloration, changes in dissolution rate and profile, and even toxicity or other pharmacological properties associated with negative side effects. During the development of an oxygen-sensitive product, studies are performed that investigate the formulation’s interaction with oxygen. End-of-shelf-life stability studies verify that the product indeed retains efficacy under specified headspace oxygen levels. Such studies allow for the specification of appropriate initial headspace oxygen levels in the primary packaging. Finally, headspace oxygen levels are often monitored during the filling process as an in-process control (IPC) of the purging system used to bring headspace oxygen levels below the required specification.

Unfortunately, existing analytical methods for oxygen analysis in the headspace of parenteral containers are slow and/or destructive. This results in headspace oxygen analysis which is both time and resource intensive. Conventional destructive techniques, such as electrochemical methods or gas chromatography, are difficult to implement at- or in-line for immediate feedback about the filling process. The destructive nature of the measurement also means that these conventional methods cannot be utilized for 100% inspection of product. Once the septum of the container is pierced to take a headspace sample, container integrity is compromised. Product is therefore destroyed and costs are incurred as a result of the destruction and disposal of analyzed samples.