Isotopic fingerprinting of goods−providing evidence for counterfeit pharmaceuticals

by Eric Jamin, Freddy Thomas, Michele Lees, Eurofins Analytics, France

Ensuring the safety and efficacy of pharmaceuticals in an increasingly complex global supply chain is a major concern for government agencies worldwide. The most common fraudulent practice involves a medicine that contains the wrong or no active ingredient, or even the right active ingredient but at the wrong dose. There are however other more sophisticated practices such as the deliberate copying of existing patents for processes or formulations or the relabelling of stolen drugs or of their provenance to circumvent anti-dumping measures or to benefit from a "clear status" of a producing country.

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 provides 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 nuclei (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, in addition to the better-known 2H SNIF-NMR. The combined information from multi-element IRMS measurements and from 2H and 13C SNIF-NMR creates a unique isotopic fingerprint of a compound. 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 25 years ago based on their patented SNIF-NMR technology, the Group has the scientific experience and expertise to support clients' most challenging testing projects.

For more information contact: asmnantesauthenticity@eurofins.com

References

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