Isotopic fingerprinting: an efficient method to characterise pharmaceutical molecules

Eric Jamin, Authenticity BU Manager; Freddy Thomas, Authenticity BU R&D Manager; Eurofins Analytics, asmnantesauthenticity@eurofins.com

The World Health Organisation estimates counterfeit pharmaceuticals at more than 10% of the global medicine market. The products most affected include both bulk ingredients, in which Active Pharmaceutical Ingredients (APIs) are produced and purchased in bulk for use in the manufacturing of finished pharmaceuticals, and the finished products themselves. The issues that are often implicated in bulk ingredients are the infringement of patent and trademark rights.

Given the wide range of products and practices that come under the “counterfeit” umbrella, no single method is available for the identification and prevention of counterfeit medicines. Amongst the anti-counterfeiting technologies that have been developed are those based on stable isotope analyses, in which the unique chemical properties of a substance provide forensic evidence of its manufacturing process or the raw materials used.

The two most commonly used methods for measuring stable isotope ratios are IRMS (Isotope Ratio Mass Spectrometry), which measures isotope ratios of several elements (C, H, N, O, S), and SNIF-NMR (Site-specific Natural Isotope Fractionation studied by Nuclear Magnetic Resonance spectroscopy), which provides information on different molecular sites simultaneously. Recent technological developments have made it possible to measure site-specific 13C/12C ratios directly using quantitative 13C NMR, improving the ability to investigate the origin of active ingredients. This “isotopomic” approach has been applied to the authentication of commonly used generic pharmaceuticals, such as ibuprofen and naproxen, demonstrating its potential to provide evidence in cases of patent infringement or to help track a product along its supply chain.

As Eurofins Scientific was founded 30 years ago based on its patented SNIF-NMR technology, the Group has the scientific experience and expertise to support clients’ most challenging testing projects. For more information visit: www.eurofins.com