Discrimination of Falsified Erectile Dysfunction Medicines by Use of an Ultra-Compact Raman Scattering Spectrometer

Abstract

Substandard and falsified medicines are often reported worldwide. An accurate and rapid detection method for falsified medicines is needed to prevent human health hazards. Raman scattering spectroscopy has emerged as a non-destructive analysis method for the detection of falsified medicines. In this laboratory study, Raman spectroscopy was performed to evaluate the applicability of the ultra-compact Raman scattering spectrometer (C13560). Principal component analysis (PCA) was also performed on the Raman spectra. This study analyzed tadalafil (Cialis), vardenafil (Levitra), and sildenafil (Viagra) tablets. We tested the standard product and products purchased from the internet (genuine or falsified). For Cialis and Levitra, all falsified tablets were identified by the Raman spectra and PCA score plot. For Viagra, the Raman spectra of some falsified tablets were almost comparable to the standard tablet. The PCA score plots of falsified tablets were dispersed, and some plots of falsified tablets were close to the standard tablet. In conclusion, C13560 was useful for the discrimination of falsified Cialis and Levitra tablets, whereas some falsified Viagra tablets had Raman spectra similar to that of the standard tablet. The development of detection methods that can be introduced in various settings may help prevent the spread of falsified products.

Detection Method of Falsified Medicines by Using a Low-Cost Raman Scattering Spectrometer Combined with Soft Independent Modeling of Class Analogy and Partial Least Squares Discriminant Analysis

“…A likely factor is that Cialis, Levitra, and Viagra are all film-coated tablets, and the Raman spectra are influenced by additive agents in the coating layer. 51) The standard PCA models of Cialis, Levitra, and Viagra were all affected by peaks of similar wavenumber, suggesting that the three standard PCA models were similar (Fig. 7).…”

“…The authenticity of the samples was judged by the manufacturers, and the quality was confirmed using the HPLC method used in previous studies. [48][49][50]52) We also obtained one Diflucan falsified sample from the manufacturer.…”

“…Falsified medicines distributed on the market may show no or wrong information about their contents, contain no active pharmaceutical ingredient, and some falsified medicines are very similar to the genuine products because companies manufacturing falsified products have improved their techniques. 5,[48][49][50] In our previous study, which used an ultra-compact Raman scattering spectrometer to discriminate between genuine and falsified tablets by PCA, the methods of discriminant analysis were not considered. 51) To solve this issue, we developed a detection method that combines Raman scattering spectroscopy with SIMCA and PLS-DA.…”

“…5,[48][49][50] In our previous study, which used an ultra-compact Raman scattering spectrometer to discriminate between genuine and falsified tablets by PCA, the methods of discriminant analysis were not considered. 51) To solve this issue, we developed a detection method that combines Raman scattering spectroscopy with SIMCA and PLS-DA. We used authentic standard products as a calibration set, and medicines actually distributed on the market (genuine and falsified) as a test set.…”

“…The medicines were four products for which falsified products have been reported before. [48][49][50]52,53) Tadalafil (Cialis), vardenafil hydrochloride (Levitra), and sildenafil citrate (Viagra) tablets, which are medicines for erectile dysfunction (ED), and fluconazole (Diflucan) tablet is an antifungal medicine, which is sometimes advertised as female Viagra online.…”