Physical profiling and IR spectroscopy: simple and effective methods to discriminate between genuine and counterfeit samples of Viagra® and Cialis®

Abstract

Counterfeit medicines are a global threat to public health. High amounts enter the European market, enforcing the need for simple techniques to help customs detect these pharmaceuticals. This study focused on physical profiling and IR spectroscopy to obtain a prime discrimination between genuine and illegal Viagra® and Cialis® medicines. Five post-tableting characteristics were explored: colour, mass, long length, short length, and thickness. Hypothesis testing showed that most illegal samples (between 60 and 100%) significantly differ from the genuine medicines, in particular for mass and long length. Classification and Regression Trees (CART) analysis resulted in a good discrimination between genuine and illegal medicines (98.93% correct classification rate for Viagra®, 99.42% for Cialis®). Moreover, CART confirmed the observation that mass and long length are the key physical characteristics which determine the observed discrimination. IR analysis was performed on tablets without blister and on tablets in intact blister. These data were analyzed using Soft Independent Modelling of Class Analogy (SIMCA) and Partial Least Squares - Discriminant Analysis (PLS-DA). Supervised techniques needed to be applied since Principal Component Analysis (PCA) was not able to generate the desired discrimination. Our study shows that a perfect discrimination between genuine and illegal medicines can be made by both SIMCA and PLS-DA without removing the tablets from the blister. This approach has the advantage of keeping the blister intact. Our study demonstrates that these user friendly techniques are reliable methods to aid customs to obtain a prime distinction between genuine and illegal samples on the spot. Copyright © 2015 John Wiley & Sons, Ltd.

A drug identification model developed using deep learning technologies: experience of a medical center in Taiwan

“…For medication adherence and drug preservation, most drugs are packaged in blisters [37]. Moreover, for some drugs, infrared spectrum analysis of tablets in intact blisters is performed to distinguish between genuine and counterfeit samples [38]. DLDI models may also be applied to automated dispensing cabinets (ADCs), and can be employed in cooperation with both pharmacists and robots.…”

ATR-FTIR characterization of generic brand-named and counterfeit sildenafil- and tadalafil-based tablets found on the Brazilian market

“…Although several studies based on infrared profiling [12,[14][15][16][17][18][19][20] have been published over this decade concerning identification of counterfeit samples of Viagra and Cialis, most of these works do not consider nor discuss the compositional characteristics of the samples, employing spectral profiling mostly as a data source for chemometrical analysis, an approach which, although very powerful and useful, is usually beyond practical use in most forensic laboratories. The present approach was based on more direct and comparative practical analyses of the spectral profiles of tablet cores, applied not only to identify the AI of each tablet, but also the major excipients/adjuvants present.…”

Spectroscopic and Spectrometric Methods Used for the Screening of Certain Herbal Food Supplements Suspected of Adulteration

“…De Veij et al, detected counterfeit Viagra tablets using Raman while Trefi et al, using Raman spectroscopy and NMR (Nuclear Magnetic Resonance) identified counterfeit Cialis tablets illegally sold on the internet. 17-20 Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (ATR-FTIR) and IR Spectroscopy were used to detect counterfeit drugs like Viagra and Cialis type by Ortiz et al, and Custers et al 21,22 Using the same techniques, Champagne et al, detected sildenafil and tadalafil in raw materials used as ingredients in food supplements. 23 Chuang et al, and Yang et al, used near-infrared spectroscopy (NIR) to analyze bioactive compounds in herbs and herbal medicines, respectively.…”