Low-cost spectroscopy test detects counterfeit medicines

Scientists in Poland are putting a rapid, cheap spectroscopy technique through its paces as a way to screen tablets for counterfeits.

Using genuine and counterfeit samples of Pfizer's erectile dysfunction treatment Viagra (sildenafil), the team from the University of Silesia tested directional reflectance (DR) to see if it could be a "simple, reproducible and inexpensive method for distinguishing between original and counterfeit medicines."

The researchers carried out DR - a combination of near and mid infrared reflection spectroscopy - using a commercially-available handheld analyser produced by Surface Optics.

The device was used to scan 32 tablets, including both genuine Viagra sourced from a pharmacy in Poland and confirmed counterfeits bought from four separate sellers operating on the Internet, which with the naked eye looked remarkably similar.

Using DR, the team were able to distinguish between genuine and fake tablets with a high degree of accuracy and reproducibility in less than five seconds per sample, even when the samples had identical chemical compositions.

While DR does not have the analytical power of other spectroscopic technologies such as NIR and Raman, the scientists see DR as a supplementary technology that could be used "in the field by the police, border guards and other services without any training."

The device is portable, lightweight and inexpensive and enables a fast, unequivocal response to the question whether a given drug is false or original," they report.

"This allows for screening, rapid analysis of hundreds of samples and - if they are found counterfeit - they can be further analysed using more specific methods."

At the moment the technique is only really applicable to solid oral dosage forms, but the researchers suggest it could be adapted for other formulations such as liquids.

The research is published in the Journal of Pharmaceutical and Biomedical Analysis (May 30, 2016).