Screening of unapproved drugs using portable Raman spectroscopy.

We present a four-step screening approach for unapproved drugs. The screening approach is both qualitative and quantitative in design in order to determine if the sample under study contains the correct and acceptable amount of the declared active pharmaceutical ingredient. Four commercially-available unapproved antibiotic and antiviral drugs were used in this study. Out of the 40 individual samples tested, 100% of the samples matched for the declared active pharmaceutical ingredient with no false positives. Following this qualitative identification step, a quantitative assay was used to determine the potency of the product. The assay involves dissolving the sample in water and using a partial least squares model to predict the potency of the product. The average Raman potency results for the four products tested were compared with chromatographic reference methods and the spectroscopic data were found to be within ∼1-6% of those obtained with the reference method for the four products tested. The results indicate that aqueous-based Raman assays may be a suitable field-deployable alternative to traditional techniques run in a laboratory environment.