Solid state 13C NMR spectroscopy as a tool for identification of counterfeit Viagra tablets and guide for develop new identification approach of falsified product

Abstract

Counterfeit drugs are a global problem that is directly related to the safety and effectiveness of pharmacotherapy. The black market for counterfeit products is constantly growing and related to the wide availability through online shopping. Therefore, there is a constant need to develop analytical methods that would allow for the unambiguous identification of counterfeit products from the original ones. One of such techniques is solid-state NMR spectroscopy, which allows for direct registration and analysis of spectra of multicomponent solid forms of pharmaceutical formulations. The paper explores the possibility of using this technique in the identification of counterfeit Viagra tablets. In this study, solid-state NMR has been used to detect the non-pharmacopoeial cellulose present in the samples of counterfeit Viagra tablets. Besides, the NMR results allowed to develop a rapid dying technique that can be used to distinguish between the counterfeit and original drug. It has been shown that solid-state NMR spectroscopy allows for numerous analyses such as identification of counterfeit products, assessment of the composition of analyte, estimation of qualitative differences between the original and falsified product, and the development of simple analytical methods based on tablets composition differences.