New technique can identify counterfeit drugs

NEW YORK, Jan 30 (Reuters) A new method of verifying the ingredients of a pharmaceutical product without opening the package is more accurate than the conventional methods of analysis, scientists in the UK report in a study scheduled for publication in the March 1 issue of Analytical Chemistry.

''Spatially offset Raman spectroscopy'' or SORS can probe deep layers of material, separating out interfering signals emanating from packaging, drug coatings, and inactive ingredients. In that way, SORS authenticates the actual content and concentration of a drug, Dr Pavel Matousek and Dr Charlotte Eliasson of the CCLRC Rutherford Appleton Laboratory in Oxfordshire report. It can do so without ever having to open a package, they say.

Fake drugs have become an ever-increasing problem worldwide, the authors note. Sometimes a product has the correct molecule, but its altered formulation may decrease its effectiveness or the concentration may be wrong. Other times, the product may have none of the ingredients that it claims to contain. But if a package has to be opened to verify its contents, it can no longer be marketed.

Conventional spectroscopy has an ''exceptionally high chemical specificity,'' and can provide an accurate fingerprint of a molecule, the researchers point out. Scattered light from a molecule illuminated by a laser is collected by a lens and sent through a monochromator onto a detector for analysis. However, packaging or other ingredients in the product can produce too much ''noise'' for conventional spectroscopy to work.

In 2005, Matousek and associates published data on the SORS approach, in which the spectra of the material are collected some distance away from the point of illumination on the sample. This way, interfering signals of the individual layers can be separated out.

Now, Matousek and Eliasson have analyzed multiple containers of ibuprofen and paracetamol (acetaminophen) packaged as blister packs or in plastic bottles or jars. Each product was analyzed by SORS and by conventional spectroscopy.

Their results showed that with the conventional approach, intense spectral bands from the packaging would often overlap those of the drug being analyzed. But by using SORS, the signal from the packaging is effectively suppressed, thus providing a more sensitive readout, the two scientists conclude.

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