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Pharmaceutical Applications of Electron Paramagnetic Resonance Spectroscopy: An Overview

Electron Paramagnetic Resonance (EPR) spectroscopy is a magnetic resonance technique that can non-invasively detect impurities involved in the degradation of pharmaceutical properties. EPR detects the unpaired electrons that occur in paramagnetic substances. Unpaired electrons occur in free radicals and many transition metals, and EPR is the only technique that can qualify and quantify the presence of these impurities.

In this webinar, applications scientists Kalina Ranguelova and Ralph Weber from Bruker BioSpin discuss how the detection of these impurities by EPR is beneficial in at least five areas of pharmaceutical product manufacture. They also introduce Bruker’s new addition to the EMX spectrometer range − the EMXnano − a high-end, compact, and affordable bench-top EPR spectrometer with many features that are usually only provided by advanced, floor-standing instruments.

During the manufacture, transportation and storage of pharmaceutical products, degradation products can arise that compromise a product’s stability and therefore efficacy. Even trace amounts of these impurities can affect drug safety and cause adverse effects in patients. It is therefore essential for manufacturers to determine degraded active pharmaceutical ingredients (APIs), excipients and formulations and to identify any processes involved in reaction monitoring, sterilization, stress testing and impurity profiling that may contribute to product degradation.

Factors that cause degradation and compromise the stability of a pharmaceutical product include heat, light, oxygen, moisture, sterilization processes, impurities and excipient interactions. EPR can be used to detect and evaluate this degradation, since the degradation often involves free radicals and transition metals and is correlated with the EPR signal. In the webinar, Kalina and Ralph discuss how EPR and the EMXnano can help manufacturers determine the cause and extent of this degradation, to predict a product’s long-term stability characteristics.

A process called stress testing is an important part of optimizing product stability and shelf-life. During stress testing, the drug product is subjected to forced oxidation/degradation to test its stability. This validated quantitative procedure detects changes in drug product properties over time under the influence of environmental factors such as light, heat and chemical agents. Exposure to these factors decomposes the product, which causes free radical production. Here, Ralph Weber describes how EPR and the EXMnano can be used to monitor this process, to predict the product’s stability in the long-term. Weber also talks about how the EXMnano can be useful for testing how effective antioxidants are at quenching free radicals.

Reaction monitoring is crucial to understanding, optimizing and scaling up drug manufacture processes. Understanding the mechanisms underlying a reaction ensures the quality of the final product and leads to significant cost savings. In the webinar, Kalina outlines how kinetic information and models can be used to predict the conditions that will enable effective optimization, risk assessment and control of processes. Understanding the chemistries that involve free radicals and transition metals enables manufacturers to maximize product yield and minimize the environmental footprint. The webinar addresses how EPR and the EXMnano help with this, as well as providing an example of Merck using EPR for reaction monitoring.

During drug manufacture, proper sterilization of APIs, excipients, formulations, medical devices and lab equipment is essential. However, the process can generate free radicals that degrade irradiated materials, lead to alteration of the product’s properties and decrease potency through partial product decomposition. The free radicals may also be a toxicological hazard. The webinar discusses how EPR with the EMXnano can provide a solution to these problems, as well as helping manufacturers make easy ‘go/no go’ for quality control procedures.

Kalina goes into detail about how the drug impurities that can arise from APIs or excipients or through formulation processes, packaging and storage are associated with numerous unwanted effects such as reduced therapeutic impact, decreased shelf-life and toxicity. It is described how EPR and the EMXnano can be used to detect and identify traces of transition metals, to monitor degradation processes that generate and involve free radicals and to observe free radical production catalysed by transition metals or other impurities.

The webinar presenters also talk about the compactness of the EMXnano compared with other available instruments, as well as many other features the instrument offers to ensure a combination of easy operation and the highest quality EPR data.

To learn about the pharmaceutical applications of EPR and Bruker’s EMXnano in more detail, please click here to register and listen to the webinar.