Classification and Visualization of Physical and Chemical Properties of Falsified Medicines with Handheld Raman Spectroscopy and X-Ray Computed Tomography

Research on the Development of Methods for Detection of Substandard and Falsified Medicines by Clarifying Their Pharmaceutical Characteristics Using Modern Technology

The existence of substandard and falsified medicines threatens people's health and causes economic losses as well as a loss of trust in medicines. As the distribution of pharmaceuticals becomes more globalized and the spread of substandard and falsified medicines continues worldwide, pharmaceutical security measures must be strengthened. To eradicate substandard and falsified medicines, our group is conducting fact-finding investigations of medicines distributed in lower middle-income countries (LMICs) and on the Internet. From the perspective of pharmaceutics, such as physical assessment of medicines, we are working to clarify the actual situation and develop methods to detect substandard and falsified medicines. We have collected substandard and falsified medicines distributed in LMICs and on the Internet and performed pharmacopoeial tests, mainly using HPLC, which is a basic analytic method. In addition to quality evaluation, we have evaluated the applicability of various analytic methods, including observation of pharmaceuticals using an electron microscope, Raman scattering analysis, near-IR spectroscopic analysis, chemical imaging, and X-ray computed tomography (CT) to detect substandard and falsified medicines, and we have clarified their limitations. We also developed a small-scale quality screening method using statistical techniques. We are engaged in the development of methods to monitor the distribution of illegal medicines and evolve research in forensic and policy science. These efforts will contribute to the eradication of substandard and falsified medicines. Herein, I describe our experience in the development of detection methods and elucidation of the pharmaceutical status of substandard and falsified medicines using novel technologies.

A critical review on the availability of substandard and falsified medicines online: Incidence, challenges and perspectives

Simultaneous expansion of the Internet and increased globalisation of the pharmaceutical industry have meant medication can be accessed transnationally from both legal and illicit sources. This has coincided with the rise of substandard and falsified medicines (SFMs) online. These products fail to meet regulatory or quality standards and/or are constituted with substandard ingredients, causing undesired pharmacological effects, including possible injury and death. This review aimed to identify original research studies that examined characteristics of SFM online sales, attitudes towards purchasing medicines online and strategies to address this drug safety challenge. Keywords of ‘Substandard’ and ‘Falsified’/‘Counterfeit’ and ‘Medicines’/‘Drugs’ and ‘Online’/‘Internet’ were searched using Web of Knowledge and PubMed databases. Resulting literature, which satisfied the study’s inclusion criteria, was included in the review, and the findings from each paper were assessed. From an initial 185 literature articles, 7 were eligible according to the inclusion criteria to be reviewed. These articles identified studies testing SFMs purchased online, surveys of attitudes and knowledge about SFMs online, and website content analysis to detect illegal online sales. Challenges identified were lack of knowledge and awareness among consumers and physicians, in addition to the use of direct-to-consumer-advertising, via Internet platforms and social media, providing easy access to SFMs. Despite this, medicine authentication technology, website verification approaches and new detection methods were identified as potential solutions specific to online SFM sales. To address online sales of SFMs, more robust research, greater awareness/educational programmes, analytical detection methods and more stringent online global governance are required.

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

There are many reports of falsified medicines that may cause harm to patients. A rapid and simple method of identifying falsified medicines that could be used in the field is required. Although Raman scattering spectroscopy has become popular as a non-destructive analysis, few validation experiments on falsified medicines that are actually distributed on the market have been conducted. In this study, we validated a discriminant analysis using an ultra-compact, portable, and low-cost Raman scattering spectrometer combined with multivariate analysis. The medicines were three types of erectile dysfunction therapeutic tablet and one type of antifungal tablet: tadalafil (Cialis), vardenafil hydrochloride (Levitra), sildenafil citrate (Viagra), and fluconazole (Diflucan), which is sometimes advertised as female Viagra. For each medicine, the authentic standard product and products obtained by personal import via the internet (genuine or falsified) were used. Discriminant analyses were performed on the Raman spectra combined with soft independent modeling of class analogy (SIMCA) and partial least squares discriminant analysis (PLS-DA). It was possible to identify all falsified samples by SIMCA using the standard product model for all four products. Using the PLS-DA using the PLS models of the four standard products, falsified Levitra and Diflucan samples were classified correctly, although some falsified Cialis and all Viagra samples also belonged to the standard class. In this study, SIMCA might be more suitable than PLS-DA for identifying falsified medicines. A spectroscopic module that combines the low-cost Raman scattering spectroscopy with SIMCA might contribute to the rapid identification of falsified medicines in the field.

Quality assessment of Diflucan® tablets distributed online: Diflucan® distributed online

Background:

Falsified medical products have been reported worldwide. Falsified medicines with poor quality are a potential health hazard. Some Internet sites advertise fluconazole (Diflucan^®), an antifungal medicine used to treat deep mycoses, as “female Viagra^®.”

Aim:

The aim of this study was to investigate the authenticity and quality of Diflucan^® tablets distributed on the Internet.

Methods:

We ordered Diflucan^® tablets via the Internet and evaluated them by visual observation, authenticity investigation, quality evaluation (quantity of the active pharmaceutical ingredient, content uniformity, and dissolution), and near-infrared and Raman scattering spectroscopy.

Results:

We obtained 11 samples of Diflucan^® tablets from all 11 Japanese Internet sites identified in our search. Of 11 sites, 7 advertised fluconazole as having effects on female sexual function. Ten of the Diflucan^® samples were confirmed as genuine and one sample was falsified. The genuine Diflucan^® samples met the specifications of all quality evaluations. The packaging, size, and color of the falsified Diflucan^® sample obtained in this study differed from the authentic Diflucan^® tablet. The falsified Diflucan^® sample obtained in this study did not contain fluconazole and instead contained what appeared to be sildenafil citrate. The spectra of the falsified Diflucan^® tablet obtained in this study differed from the authentic Diflucan^® tablet in near-infrared and Raman scattering spectroscopy.

Conclusion:

We confirmed that one falsified Diflucan^® tablet was distributed online. Thus, continued measures against falsified medicines are required.

Clarification of the internal structure and factors of poor dissolution of substandard roxithromycin tablets by near-infrared chemical imaging

The spread of substandard and falsified medicines has become a global problem, especially in low- and middle-income countries (LMICs). Previously, we found that some tablets containing the same active ingredient had large differences in their dissolution even though their contents were comparable. In this study, we investigated the poor dissolution of roxithromycin tablets using near-infrared chemical imaging (NIR-CI) to visualize the internal tablet structure. Roxithromycin tablets collected in LMICs and the pioneer product Rulid® as a reference were cut to a flat surface for analysis. NIR spectral data were normalized, and a principal component analysis was performed to create a tablet internal structure image. For Rulid®, the differences between the spectra with high and low scores were small, and well-defined aggregation of ingredients was not observed. However, large differences in the scores were found for roxithromycin tablets manufactured in some LMICs, and non-uniformity of ingredient distribution and aggregation were observed. Additionally, some pharmaceutical excipients, such as starch or magnesium stearate, were found in certain aggregates by comparing NIR spectra. The NIR-CI results showed some excipients existed as large aggregates, which indicated that the ingredients were not evenly mixed in the roxithromycin tablet, and this contributed to its poor dissolution.

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

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.

Falsified tadalafil tablets distributed in Japan via the internet

The adverse health effects of falsified medicines for erectile dysfunction have been reported in Japan. We purchased tadalafil (Cialis) tablets online and assessed their authenticity and quality. Of the 45 samples we tested, nine were genuine, 23 were falsified, nine were unregistered/unlicensed samples, and the authenticity of four samples could not be ascertained. Observation of packaging and tablet size, weight, and color revealed differences between some genuine and falsified samples. All genuine samples contained the active pharmaceutical ingredient tadalafil at adequate quantities, while falsified samples contained sildenafil (Viagra). Some falsified samples contained insufficient quantities of tadalafil. All unregistered/unlicensed samples contained neither tadalafil nor sildenafil. Some falsified samples did not dissolve/disintegrate sufficiently. The status of most samples was detectable by Raman scattering and near-infrared spectroscopy. Restricting consumer access to falsified medicines can prevent undesirable health effects.

Study of drug particle distributions within mini-tablets using synchrotron X-ray microtomography and superpixel image clustering

Uniform drug distribution within fast disintegrating tablets is a key quality measure to ensure a reliable, steady, and targeted release of the contained active pharmaceutical ingredients. In this work, the drug particle distribution in mini-tablets was studied with synchrotron phase contrast X-ray microtomography. Mini-tablets had a weight of 9.5 mg and a drug load from 2.5% to 20%. Moxidectin, a drug used for treatment of parasitic infections, was used as a model compound. Drug content covered a range from 91% to 121% of the target dose. A linear iterative clustering (SLIC) superpixel method was used for segmentation, analysis, and visualization of the spatial distribution of individual tablet components (i.e., pores, excipients, and drug). Results show that the drug was not uniformly distributed within the tablet, revealing an increasing drug load towards the tablets' outer boundaries and thus indicative of a radial displacement of drug particles during compaction. The presented method can be used for the quantitative analysis of drug content and drug distribution within pharmaceutical tablets, allowing for the optimization of fast disintegrating formulations. The results also affirm that that drug loads up to 20% will not lead to segregation for moxidectin.

Falsified vardenafil tablets available online

It is often reported that falsified medicines have harmful effects on patients both Japan and abroad. In this study, we purchased vardenafil tablets on the internet and investigated their quality and authenticity using visual observations, authenticity investigations, non-destructive tests (handheld NIR and Raman spectroscopy), and quality analyses (active ingredient content and tablet dissolution rate). We used genuine 20-mg Levitra tablets that were sold in Japan and tablets from Bayer AG (Germany) as controls. In April 2015, we obtained 28 samples from 15 websites on the internet. Our authenticity investigations revealed that 11 (40%) were genuine products and 17 (60%) were falsified products. Handheld NIR and Raman results revealed that the falsified products had different spectra to the genuine products. Principal component analysis of the NIR and Raman spectra showed variation among the falsified products. The 11 genuine products were of good quality, and the 17 falsified products were of poor quality. The falsified products contained sildenafil (the active ingredient of Viagra) or tadalafil (the active ingredient of Cialis) instead of vardenafil. Our results show that falsified Vardenafil tablets are sold on the internet and that it is important to prevent illegal internet sales and increase consumer awareness of the presence of falsified medicines.

Field detection devices for screening the quality of medicines: a systematic review

BACKGROUND

Poor quality medicines have devastating consequences. A plethora of innovative portable devices to screen for poor quality medicines has become available, leading to hope that they could empower medicine inspectors and enhance surveillance. However, information comparing these new technologies is woefully scarce.

METHODS

We undertook a systematic review of Embase, PubMed, Web of Science and SciFinder databases up to 30 April 2018. Scientific studies evaluating the performances/abilities of portable devices to assess any aspect of the quality of pharmaceutical products were included.

RESULTS

Forty-one devices, from small benchtop spectrometers to 'lab-on-a-chip' single-use devices, with prices ranging from US$20 000, were included. Only six devices had been field-tested (GPHF-Minilab, CD3/CD3+, TruScan RM, lateral flow dipstick immunoassay, CBEx and Speedy Breedy). The median (range) number of active pharmaceutical ingredients (APIs) assessed per device was only 2 (1-20). The majority of devices showed promise to distinguish genuine from falsified medicines. Devices with the potential to assay API (semi)-quantitatively required consumables and were destructive (GPHF-Minilab, PharmaChk, aPADs, lateral flow immunoassay dipsticks, paper-based microfluidic strip and capillary electrophoresis), except for spectroscopic devices. However, the 10 spectroscopic devices tested for their abilities to quantitate APIs required processing complex API-specific calibration models. Scientific evidence of the ability of the devices to accurately test liquid, capsule or topical formulations, or to distinguish between chiral molecules, was limited. There was no comment on cost-effectiveness and little information on where in the pharmaceutical supply chain these devices could be best deployed.

CONCLUSION

Although a diverse range of portable field detection devices for medicines quality screening is available, there is a vitally important lack of independent evaluation of the majority of devices, particularly in field settings. Intensive research is needed in order to inform national medicines regulatory authorities of the optimal choice of device(s) to combat poor quality medicines.

Survey to Identify Substandard and Falsified Tablets in Several Asian Countries with Pharmacopeial Quality Control Tests and Principal Component Analysis of Handheld Raman Spectroscopy

The World Health Organization has warned that substandard and falsified medical products (SFs) can harm patients and fail to treat the diseases for which they were intended, and they affect every region of the world, leading to loss of confidence in medicines, health-care providers, and health systems. Therefore, development of analytical procedures to detect SFs is extremely important. In this study, we investigated the quality of pharmaceutical tablets containing the antihypertensive candesartan cilexetil, collected in China, Indonesia, Japan, and Myanmar, using the Japanese pharmacopeial analytical procedures for quality control, together with principal component analysis (PCA) of Raman spectrum obtained with handheld Raman spectrometer. Some samples showed delayed dissolution and failed to meet the pharmacopeial specification, whereas others failed the assay test. These products appeared to be substandard. Principal component analysis showed that all Raman spectra could be explained in terms of two components: the amount of the active pharmaceutical ingredient and the kinds of excipients. Principal component analysis score plot indicated one substandard, and the falsified tablets have similar principal components in Raman spectra, in contrast to authentic products. The locations of samples within the PCA score plot varied according to the source country, suggesting that manufacturers in different countries use different excipients. Our results indicate that the handheld Raman device will be useful for detection of SFs in the field. Principal component analysis of that Raman data clarify the difference in chemical properties between good quality products and SFs that circulate in the Asian market.

Encoding matter with regiospecific 12C/13C isotopic labels

Society suffers due to an inability to regulate matter. This study presents a practical tool for the encryption of materials by adjusting the levels of ¹³C at regiospecific atoms within a molecule to generate a stable-isotopically encoded signature. This system is demonstrated by securing a document by adapting natural product chemistry as an encryption device. This approach delivers a complex signal that would be difficult to intercept due to the need for access to extraction protocols, sophisticated NMR instrumentation and a vital level of prior knowledge. Overall, this discovery offers an important tool to monitor and track valuable entities on our planet.