Stable isotopes for characterising synthetic pathways
Pharmaceuticals are subject to various forms of identity fraud, from the earliest stages of raw materials acquisition through manufacturing and final product distribution. The lack of authenticity threatens consumer confidence and product efficacy, as well as the economic well-being of the fine chemicals industry. Stable isotopic characterization or 'fingerprinting' of active pharmaceutical ingredients and selected synthons points to a new and highly specific method for patent infringement investigations and mitigation. Collectively, measurements of the abundances of naturally occurring stable isotopes were used within the COUNTERPHARM project to quantitatively characterise the sources of pharmaceutical compounds. Using isotope ratio mass spectroscopy and deuterium nuclear magnetic resonance, researchers at the Eurofins Scientific Analytics labs graphically observed the isotopic ratio patterns of widely available molecules. Samples of acetylsalicylic acid (aspirin), paracetamol and ibuprofen, commercialised by various pharmaceutical companies, were analysed to characterise the starting materials and synthetic processes used to produce them. The results demonstrated the utility of stable-isotopic analyses for monitoring and identifying molecules of pharmaceutical importance and for their manufacturers, thus providing an invaluable tool for product security and authentication. They can further be used to monitor process consistency, including changes or modifications that may occur during the various steps in a pharmaceuticals manufacturing process.
