Makers of counterfeit drugs beware: your fake products can now be detected while still in the packaging, making them much easier to intercept.
By the end of the year, hand-held devices capable of spotting packaged fakes could be available, helping inspectors seize drugs which, in some parts of south-east Asia and Africa, account for half of all medicines on sale. Hundreds of people have died after taking contaminated fakes (麻豆传媒, 9 September 2006, p 8), while others are duped into buying medicines with no active ingredients.
Many counterfeits come in packaging that is virtually identical to the real thing. But that won鈥檛 fool the detector, developed by Pavel Matousek and Charlotte Eliasson of the Rutherford Appleton Laboratory in Didcot, UK. It uses a variant of Raman spectroscopy, a routine analytical technique. Raman analysers shine laser light into a sample, causing molecules to emit infrared radiation, which is collected at the same point where the laser is focused. Each chemical emits a different range of infrared Raman frequencies, producing a unique spectral fingerprint for that substance. This enables fake drugs to be distinguishable from their genuine counterparts.
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Current devices cannot analyse substances within packaging because that material interferes with and obscures the sample鈥檚 signal. To overcome this Matousek and Eliasson modified their spectrometer to collect the returning signal at a point a few millimetres from where the laser is focused. This works because Raman signals generated deep within a sample shift sideways slightly before exiting the surface, unlike those generated on the surface itself.
The signal from the packaging surface is effectively diluted, while that from the drug inside is amplified. 鈥淏y going sideways, we avoid the blinding signal from the surface,鈥� says Matousek.
聯The packaging signal is diluted while that from the drug inside is amplified聰
Matousek has used the procedure to detect branded versions of the painkillers paracetamol and ibuprofen, both in blister packs and plastic containers (Analytical Chemistry, DOI: 10.1021/ac062223z). He says it is relatively easy to reconfigure the fibre-optic detectors within existing hand-held devices, which cost between 拢10,000 and 拢20,000, to collect scattered light 2 or 3 millimetres sideways.
鈥淔rom the standpoint of technology it looks promising, but the cost is always something we must take into account,鈥� says Howard Zucker of the International Medical Products Anti-Counterfeiting Taskforce (IMPACT), which was set up last year by the World Health Organization to spearhead a global fight against the counterfeiters. The spectrometer will be evaluated in March at a special meeting of IMPACT鈥檚 technology sub-group.
