Chemical profiling 'can detect stolen, falsified meds'

Researchers from the University of Copenhagen and Stanford University have shown it is possible to distinguish seemingly identical medicines at the molecular level, using a chemical fingerprinting technology.

The technique – described in a paper published in the journal Molecular Pharmaceutics – can differentiate products made by manufacturers in different countries and even batches from the same manufacturer, according to the scientists.

Their approach involves using isotope ratio mass spectrometry (IRMS) to identify unique carbon, hydrogen, and oxygen stable isotope signatures in medicines – in this case, 27 ibuprofen products collected from six different countries.

The medicines were all produced under unique conditions, which affects their isotopic signature. The technology could, however, be used to trace the origin of all types of medicine, according to the researchers.

"All medicines have a unique chemical fingerprint that allows identification down to the specific factory where it was produced," says Else Holmfred, a postdoc at the department of pharmacy at Copenhagen and Stanford Universities, who is the lead author of the study.

"Imagine a pharmaceutical company has a shipment of medicine stolen, which was discarded due to insufficient quality," she explains. "Later, some criminals repackage the medicine with the intent to resell it. With this technology, it’s possible to accurately determine where the medicine originally came from and thereby prove it was stolen."

The stable light isotopic analysis is a powerful tool for unique identification and for health authorities and pharmaceutical manufacturers to detect falsified and substandard drug products, protect against patent infringement, and ensure high-quality drug products, according to the paper.

"Stable isotopes are incredibly useful because they don’t change over thousands or millions of years. And since all medicines are made from synthesised organic substances or substances derived from plants, they always contain something organic and thus carbon, hydrogen, and oxygen. This could be, for example, corn starch or cellulose,” according to Stefan Stürup, co-author of the study.

"The isotopic composition of a plant substance is determined by where in the world it comes from, what type of water it used, and what type of photosynthesis it performs," he said. "Depending on this, the ratio between carbon-12 and carbon-13 changes slightly. This ratio is unique to each plant. That’s why it’s impossible to fake isotopes."

The next step in the research is to demonstrate that specific counterfeits can be found, and Holmfred is investigating this in an upcoming study.

"The follow-up study hasn’t been published yet, but I’m currently working with data where we can clearly see…that counterfeit medicine has a significantly different isotopic signature than the medicine from the manufacturer," she said.

"The tablets look almost identical, so it’s hard to document that they’re counterfeit unless you can chemically prove they’re different."