The use of hyperspectral imaging in the VNIR (400–1000 nm) and SWIR range (1000–2500 nm) for detecting counterfeit drugs with identical API composition

•SWIR hyperspectral imaging has a definite advantage over imaging in VNIR.•Higher wavelength is less sensitive to non-uniform illumination.•GLCM analysis enables to quantify homogeneity of distribution of tablet ingredients.•GLCM method is capable of distinguishing tablets with identical composition.•SWIR enables to acquiring hyperspectral images underneath the coating of the tablet.

The risk of death from taking counterfeit drugs is now greater than the probability of dying from malaria and AIDS combined (at least half a million deaths each year). At the same time, counterfeit medicines are falsified more and more “skillfully”. According to WHO about 10% of counterfeit drugs are copies of original products.The methods of hyperspectral imaging and image analysis and processing were used to detect counterfeit drugs.Original Viagra® (Pfizer) and counterfeit tablets were compared. Hyperspectral imaging was used to acquire hyperspectral data cubes from both original and counterfeit tablets in the spectral range of 400–2500 nm. Spectral parameters for both the original Viagra® and counterfeit drugs were compared. Grey-Level Co-Occurrence Matrix (GLCM) analysis and Principal Component Analysis (PCA) were performed.Hyperspectral analysis of the surface of the original Viagra® and counterfeit tablets demonstrates significant differences in reflectance (maximum difference for 1619.75 nm). The GLCM contrast for the falsified drug is on average higher than for the original one 16±4%.GLCM contrast analysis enables to quantify homogeneity of distribution of tablet ingredients and enables to distinguish tablets with identical chemical composition. SWIR (1000–2500 nm) hyperspectral imaging has a definite advantage over imaging in VNIR (400–1000 nm) – higher wavelength is less sensitive to non-uniform illumination.

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