Study backs NIR for detecting ‘expired counterfeit’ meds

Near-infrared (NIR) spectroscopy can be used to detect counterfeits created from repackaged expired tablets, says a new study.

Researchers from Yibin and Chongqing Medical Universities in China used NIR coupled with chemometrics – the use of mathematical and statistical methods to interrogate chemical data – to differentiate expired and unexpired tablets of the antibiotic levofloxacin with 97 per cent sensitivity and 100 per cent specificity.

The authors note that repackaging expired drugs to represent them as in-date medicines is a commonly encountered for of counterfeiting, particularly in developing countries. It’s particularly hard to detect as the expired drugs may or not be out of specification, so can appear okay on standard chemical testing.

They put their NIR analysis technique through its paces on 34 unexpired and 128 expired tablets of levofloxacin, and found that it could distinguish between brands, as well as expired and unexpired samples within brands and as a group as a whole.

“NIR spectroscopy is very suitable for various dosage forms because samples can be measured without any pretreatment and the time of analysis is short. Moreover, the technique is non-destructive,” write the authors.

“This model reaches acceptable performance and can be applied to drug quality supervision such as detecting repackaged expired levofloxacin. Despite the choice of levofloxacin for experiment, this method can be extended to similar drugs,” they conclude.

The study is published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.