New Laser Device That Can Detect Fake Drugs Even When These Are Packed

Counterfeit drugs are responsible for the death of thousands of people annually in some parts of South-East Asia and Africa, where they can make up half of the medicines on sale.

The counterfeit drugs can kill even on the spot, if they contain toxic compounds, or because patients do not treat themselves while taking inactive ingredients or products that could cancel the action of other medicines.

Many counterfeit drugs are in fact produced in other countries and enter another country in packaging which is virtually identical to that of the real product.

But now researchers have developed a hand-held device capable of detecting packaged fakes. This could ease the job of the inspectors because fakes can now be intercepted while still in the package.

The device is the work of Pavel Matousek and Charlotte Eliasson of the Rutherford Appleton Laboratory in Didcot, UK and employs a variant of Raman spectroscopy, a common analytical technique. Raman analyzers expel laser light into a sample, triggering molecules to emit infrared light, which is analyzed by the device.

Each chemical compound has its own range of infrared Raman frequencies, a unique spectral fingerprint for that molecule, thus fake drugs are easily distinguishable.

Current devices cannot analyze drugs within packaging because that wrapping material impairs the sample's signal. But Matousek and Eliasson solved this problem by modifying their spectrometer to pick up the returning signal at a few millimeters distance from where the laser is pointed.

This is possible because Raman signals emerged deep within a sample shift sideways slightly before getting out to the surface, while those generated on the surface itself do not, thus the signal of the surface is diluted, while that from the drug inside is increased. "By going sideways, we avoid the blinding signal from the surface," says Matousek. "The packaging signal is diluted while that from the drug inside is amplified".

The device detected in lab tests branded versions of the painkillers paracetamol and ibuprofen, both in blister packs and plastic wrapping. "From the standpoint of technology it looks promising, but the cost is always something we must take into account," says Howard Zucker of the International Medical Products Anti-Counterfeiting Taskforce (IMPACT).