Raman Barcode for Counterfeit Drug Product Detection.

Potential infiltration of counterfeit drug products-containing the wrong or no active pharmaceutical ingredient (API)-into the bona fide drug supply poses a significant threat to consumers worldwide. Raman spectroscopy offers a rapid, nondestructive avenue to screen a high throughput of samples. Traditional qualitative Raman identification is typically done with spectral correlation methods that compare the spectrum of a reference sample to an unknown. This is often effective for pure materials but is quite challenging when dealing with drug products that contain different formulations of active and inactive ingredients. Typically, reliable identification of drug products using common spectral correlation algorithms can only be made if the specific product under study is present in the library of reference spectra, thereby limiting the scope of products that can be screened. In this paper, we introduce the concept of the Raman barcode for identification of drug products by comparing the known peaks in the API reference spectrum to the peaks present in the finished drug product under study. This method requires the transformation of the Raman spectra of both API and finished drug products into a barcode representation by assigning zero intensity to every spectral frequency except the frequencies that correspond to Raman peaks. By comparing the percentage of nonzero overlap between the expected API barcode and finished drug product barcode, the identity of API present can be confirmed. In this study, 18 approved finished drug products and nine simulated counterfeits were successfully identified with 100% accuracy utilizing this method.