Vibrational spectroscopies for the identification of substandard and falsified drugs: handheld and portable devices, multispectral and hyperspectral imagers.

The aim of this review is to present an overview of the current state of substandard and falsified (SF) drugs and the use of vibrational spectroscopies for their detection. A particular emphasis is on portable and handheld devices and chemical imaging techniques such as hyperspectral and multispectral imaging. The first section is an overview of SF drugs including their definition, global impact, distribution, supply chain issues, and analytical methods for identification and control. The paper highlights the growing importance of non-destructive, low-cost, and rapid methods for the analysis of medicines, focusing on their advantages and limitations and practical on-field implementation. A bibliometric analysis summarizes publication trends and highlights the increasing use of point spectra portable and handheld devices for SF drugs detection, as well as the comparatively slower adoption of imaging techniques. Special attention is given to the development and use of spectral libraries, which are essential for accurate identification and classification. Furthermore, the review discusses the increasing need for fast computational tools and well-structured databases to support reliable spectral interpretation to strengthen the efficiency of pharmaceutical market surveillance supply chain.