Identification of counterfeit medicines from the Internet and the World market using near-infrared spectroscopy

Pharmaceutical counterfeiting is a life threatening problem affecting all countries. Counterfeit medicines may be encountered anywhere in conventional markets or from the Internet. This paper proposes a rapid and non-destructive near-infrared spectroscopic method for the identification of counterfeit medicines using the minimum number of authentic samples. As little as twenty spectra from ten tablets from a batch are required to compare a test sample to its authentic counterpart. In this respect, tablets are measured as received and the correlation coefficient of the SNV-D2 spectra between the authentic sample and the test sample is determined. A correlation coefficient of lower than 0.95 indicates that the batch fails identification. In this case, if enough authentic samples are available, principal component analysis (PCA) could be applied. The PCA scores plot of the authentic and counterfeit samples with the 95% equal frequency ellipses drawn around the authentic sample set is effective in identifying counterfeits. The method could identify 82 known counterfeit medicines out of 201 medicines supplied from the Internet and the World market. However, it is still a comparative method to identify potential counterfeits and cannot identify products without authentic samples.