An LC method for the simultaneous screening of some common counterfeit and sub-standard antibiotics

Development and validation of a simple and affordable LC-UV method for identification and assay of selected antimicrobial medicines

Antimicrobials, particularly antibiotics, are among the most common classes of drugs reported as substandard and falsified (SF) in developing countries. Therefore, it is important to develop simple and affordable analytical methods for the quality control of antimicrobial medicines. In this study, a liquid chromatographic method with ultraviolet detection (LC-UV) was developed and validated for the screening and quantification of 13 antimicrobial medicines and one beta-lactamase inhibitor in pharmaceutical formulations. LC separation was carried out on a Kinetex C18 column (150 mm × 4.6 mm, 2.6 µm) with gradient elution. The mobile phase consisted of mixtures of acetonitrile-water-10 mM phosphate buffer pH 3.5 at ratios of 3:92:5, v/v/v for mobile phase A and 50:45:5, v/v/v for mobile phase B with a flow rate of 0.5 mL/min. The screening method was intended for confirmation of the identity of the actives and validated for specificity and robustness, whereas the quantification method (using only a different detection wavelength) was further validated in terms of linearity, accuracy, sensitivity and precision (repeatability, intermediate precision). For all compounds, the method was found to be linear (r2 > 0.999), precise (%RSD < 1%), accurate (% recovery of 98-102%), sensitive, specific and robust. The developed LC method was successfully applied for the identification and assay of 12 antimicrobial samples from Ethiopia. Among the 12 samples analyzed, one (8.3%) product was confirmed to be falsified.

Risk of false pharmaceutical equivalence (non-equivalence) decisions due to measurement uncertainty

The pharmaceutical equivalence between test (generic or similar) and reference medicine is evaluated through in vitro quality tests involving multiple compliance parameters. Despite efforts to ensure the reliability of the analytical results obtained in the pharmaceutical equivalence studies, measurement uncertainties lead to a risk of false decisions. Thus, the aim of this work was to evaluate the measurement uncertainties associated with the analytical results obtained in the pharmaceutical equivalence studies of different pharmaceutical forms and to estimate the risks of false decisions in the evaluation of pharmaceutical equivalence. The measurement uncertainties associated with the test results were evaluated using the bottom-up and top-down approaches. The consumer's or producer's combined particular risks and combined total risks were estimated using the Monte Carlo method implemented in MS-Excel spreadsheet (available as supplemental material). Considering the seven pharmaceutical equivalence studies performed in this work, three studies were not conclusive (risk of false pharmaceutical equivalence decisions higher than 5 %). Moreover, we concluded pharmaceutical equivalence and pharmaceutical non-equivalence in one and three studies, respectively. The particular and total combined risks are useful to make decisions regarding the evaluation of pharmaceutical equivalence between the test (generic or similar) and reference medicines. Regulatory bodies and pharmaceutical equivalence centers are very interested in the estimation of the risks of false decisions, particularly to evaluate the quality of medicines that are not submitted to bioequivalence studies.

Measurement Uncertainty and Conformity Assessment Applied to Drug and Medicine Analyses - A Review

Analytical results are often used in scientific research, industrial and clinical applications to support decision making. Despite all efforts to ensure the reliability of analytical results (including method validation, internal quality control, use of certified reference materials, proficiency tests, and ISO 17025 accreditation), there will always be an uncertainty associated with the measured value. The measurement uncertainty expresses the quality of the analytical result and allows the comparability between analytical results or between the measured value and the specification limit(s). This work discusses the importance of measurement uncertainty, including the steps involved in the measurement uncertainty evaluation, the bottom-up and top-down approaches used in measurement uncertainty calculation, the measurement uncertainty evaluation in drug and medicine analyses, and the application of measurement uncertainty in conformity assessment for quality control, stability studies, and pharmaceutical equivalence.

Measurement uncertainty of β-lactam antibiotics results: estimation and clinical impact on therapeutic drug monitoring

Background Despite that measurement uncertainty data should facilitate an appropriate interpretation of measured values, there are actually few reported by clinical laboratories. We aimed to estimate the measurement uncertainty of some β-lactam antibiotics (β-LA), and to evaluate the impact of reporting the measurement uncertainty on clinicians' decisions while guiding antibiotic therapy. Methods Measurement uncertainty of β-LA (aztreonam [ATM], cefepime [FEP], ceftazidime [CAZ], and piperacillin [PIP]) values, obtained by an UHPLC-MS/MS based-method, was estimated using the top-down approach called the single laboratory validation approach (EUROLAB guidelines). Main uncertainty sources considered were related to calibrators' assigned values, the intermediate precision, and the bias. As part of an institutional program, patients with osteoarticular infections are treated with β-LA in continuous infusion and monitored to assure values at least 4 times over the minimal inhibitory concentration (4×MIC). We retrospectively evaluated the impact of two scenarios of laboratory reports on clinicians' expected decisions while monitoring the treatment: reports containing only the β-LA values, or including the β-LA coverage intervals (β-LA values and their expanded measurement uncertainties). Results The relative expanded uncertainties for ATM, FEP, CAZ and PIP were lower than 26.7%, 26.4%, 28.8%, and 25.5%, respectively. Reporting the measurement uncertainty, we identified that clinicians may modify their decision especially in cases where 4×MIC values were within the β-LA coverage intervals. Conclusions This study provides a simple method to estimate the measurement uncertainty of β-LA values that can be easily applied in clinical laboratories. Further studies should confirm the potential impact of reporting measurement uncertainty on clinicians' decision-making while guiding antibiotic therapy.

Counterfeit formulations: analytical perspective on anorectics

Purpose

This paper examines the scope of anorectics in counterfeit weight-reducing formulations and provides insight into the present state of research in determining such adulterants. Analytical techniques utilised in profiling adulterants found in slimming products, including limitations and mitigation steps of these conventional methods are also discussed. The current legal status of the anorectics and analogues routinely encountered in non-prescription slimming formulations is also explored.

Methods

All reviewed literature was extracted from Scopus, Web of Science, PubMed, and Google Scholar databases using relevant search terms, such as, ‘counterfeit drugs’, ‘weight loss drugs’, ‘weight-reducing drugs’, ‘slimming drugs’, ‘anorectic agents’, and ‘counterfeit anorexics’. Legislation related to anorectics was obtained from the portals of various government and international agencies.

Results

Anorectics frequently profiled in counterfeit slimming formulations are mostly amphetamine derivatives or its analogues. Five routinely reported pharmacological classes of adulterants, namely anxiolytics, diuretics, antidepressants, laxatives, and stimulants, are mainly utilised as coadjuvants in fake weigh-reducing formulations to increase bioavailability or to minimise anticipated side effects. Liquid and gas chromatography coupled with mass spectrometric detectors are predominantly used techniques for anorectic analysis due to the possibility of obtaining detailed information of adulterants. However, interference from the complex sample matrices of these fake products limits the accuracy of these methods and requires robust sample preparation methods for enhanced sensitivity and selectivity. The most common anorectics found in counterfeit slimming medicines are either completely banned or available by prescription only, in many countries.

Conclusions

Slimming formulations doped with anorectic cocktails to boost their weight-reducing efficacy are not uncommon. Liquid chromatography combined with mass spectrometry remains the gold standard for counterfeit drug analysis, and requires improved preconcentration methods for rapid and quantitative identification of specific chemical constituents. Extensive method development and validation, targeted at refining existing techniques while developing new ones, is expected to improve the analytical profiling of counterfeit anorectics significantly.

Monitoring the complex occurrence of pesticides in the Llobregat basin, natural and drinking waters in Barcelona metropolitan area (Catalonia, NE Spain) by a validated multi-residue online analytical method

The European Directive 98/83/CE legislates the presence of pesticides in drinking water, but apart from a few compounds, nothing is said about which pesticides should be monitored. Nevertheless, water companies need to go beyond the accomplishment of the legislation and find out pesticide contamination in all sources of water in order to manage the hazard assessment, and to guarantee safe drinking water to all the population. The aim of this work was to develop an analytical multi-residue method for circa 100 compounds. The method analyses previously monitored compounds in Barcelona city and its metropolitan area, as well as many emerging pesticides and some transformation products. An on-line sample extraction (0.75 mL) coupled to fast UHPLC-MS/MS method was developed. Good linearity (r² > 0.995, with less residuals than 15%), accuracies and precisions under 25%, and acceptable expanded uncertainties were obtained for most of the monitored compounds, according to ISO/IEC 17025, obtaining limits of quantification between 5 and 25 ng/L for all compounds. A monitoring campaign on natural and treated waters in the Barcelona metropolitan area was carried out during 2016-2017. Results showed that pesticide contamination at the low stretch of Llobregat River and in its aquifer is severe. The maximum concentrations were in the range of few μg/L for carbendazim, DEET, diuron and propiconazole, and in the range 0.1-0.5 μg/L for bentazone, imidacloprid, isoproturon, simazine, metazachlor, methomyl, terbutryn and tebuconazole. However, the efficiency of advanced treatments in the DWTPs involved in drinking water production in the Barcelona metropolitan area allows the complete removal of pesticides and a safe water production for consumers. The method shows a good analytical performance for most compounds with a fast sample preparation and analysis. In addition, it has updated the knowledge about the occurrence of pesticides in the Barcelona city area.

Poor-Quality and Counterfeit Drugs: A Systematic Assessment of Prevalence and Risks Based on Data Published From 2007 to 2016

Counterfeit drugs can hurt patients and harm the pharmaceutical industry. In 2006, the International Medical Products Anti-Counterfeiting Taskforce expressed a need to generate more and better data to calculate a worldwide prevalence of counterfeiting. This review analyzes field test data that were published in the time frame January 2007 to December 2016, were accessible via Pubmed, and which addressed the prevalence of counterfeit drugs. Based on the 41 studies identified, it is still not possible to make a reliable statement about the prevalence of counterfeit drugs due to the heterogeneity of the results. To make further progress in this area, both the quantity and quality of documented field tests should be increased. Without a differentiated analysis considering therapeutic class, source, and country of counterfeit drugs, it will remain difficult to identify the root causes of market infiltration and useful points of attack to combat them. Studies with high sample power and randomized sampling, packaging inspection, and detailed chemical analysis will be necessary to correctly identify (especially professional) counterfeit samples. The classification system presented in this review should help to calculate not only the prevalence of counterfeit drugs but also the risks to the patient associated with different types of counterfeited medicines.

Near infrared spectroscopy for counterfeit detection using a large database of pharmaceutical tablets

Medicine counterfeiting is one of the current burdens of the pharmaceutical world. Reliable technologies have become available for the chemical analysis of suspect medicines. Near infrared spectroscopy (NIRS) allows for instance fast, specific and non-destructive authentication of pharmaceutical products. In this paper, a NIRS method is presented for the identification of 29 different pharmaceutical product families of tablets, one family containing one or more formulation (s), e.g. different dosages. This selection represents the whole tablet portfolio of our firm. The high number of product families constituted a challenge, given that the measurement of the samples, made on two similar instruments, generated a dataset of 7120 spectra. Several chemometric tools proved efficient for the identification of these medicines. The dataset was first investigated with a Principal Component Analysis (PCA) in order to provide an overview of the distribution of the samples. The K-Nearest Neighbors (KNN), the Support Vector Machines (SVM) and the Discriminant Analysis (DA) supervised classification tools were successfully applied and generated an outstanding classification rate of 100% of correct answer. The methods were then fully validated with an independent set of spectra. The DA was selected as the method for the routine analysis of suspect tablets with the Mahalanobis distance as acceptance criterion for identification. Counterfeits, generics and placebos samples, constituting a second validation set, were tested and rejected by the method. NIRS has thus been demonstrated as an efficient tool for the quick identification of a large dataset of pharmaceutical tablets and the detection of counterfeit medicines.

Counterfeit drugs and medical devices in developing countries

The World Health Organization has reported that counterfeit medicines potentially make up more than 50% of the global drug market, with a significant proportion of these fake products being encountered in developing countries. This occurrence is attributed to a lack of effective regulation and a weak enforcement capacity existing in these countries, with an increase in this trade resulting from the growing size and sophistication of drug counterfeiters. In addition, due to both cost and lack of availability of medicines, consumers in developing countries are more likely to seek out these inexpensive options. The World Health Organization is mindful of the impact of counterfeit drugs on consumer confidence in health care systems, health professionals, the supply chain, and genuine suppliers of medicines and medical devices. Antibiotics, antituberculosis drugs, and antimalarial and antiretroviral drugs are frequently targeted, with reports of 60% of the anti-infective drugs in Asia and Africa containing active pharmaceutical ingredients outside their pharmacopoeial limits. This has obvious public health implications of increasing drug resistance and negating all the efforts that have already gone into the provision of medicines to treat these life threatening conditions in the developing world. This review, while focusing on counterfeit medicines and medical devices in developing countries, will present information on their impact and how these issues can be addressed by regulation and control of the supply chain using technology appropriate to the developing world. The complexity of the problem will also be highlighted in terms of the definition of counterfeit and substandard medicines, including gray pharmaceuticals. Although this issue presents as a global public health problem, outcomes in developing countries where counterfeit drugs to treat malaria, tuberculosis, and human immunodeficiency virus/acquired immunodeficiency syndrome not only result in drug resistance, but a number of deaths from the untreated disease, is in stark contrast with the developed world, where lifestyle drugs such as sildenafil (Viagra®) are most commonly counterfeited.

Validation and uncertainty estimation of a multiresidue method for pharmaceuticals in surface and treated waters by liquid chromatography-tandem mass spectrometry

The estimation of measurement uncertainty associated with quantitative results is essential to assure the reliability of analytical methods and mandatory when a laboratory implements ISO standard 17025. In this work, a quantitative multi-residue method based on solid-phase extraction (SPE) and ultra-performance liquid chromatography tandem mass spectrometry detection (LC-MS/MS) has been developed and validated for the analysis of 53 pharmaceuticals (analgesics, anti-inflammatories, antibiotics, lipid regulating agents, cholesterol lowering stating agents, gastric drugs, X-ray, and miscellaneous compounds such as sildenafil, prednisone, triclosan, chlorhexidine and miconazole) in surface and drinking waters. A full validation of the method, according to ISO standard 17025 procedure, was performed. Linearity (0.01-250 ng/L range), intra-day precision (3-19%RSD in surface water and 2-19%RSD in drinking water) and inter-day precision (3-16%RSD in surface water and 1-18%RSD in drinking water), matrix effects (low matrix effects were observed for 50% of compounds in both matrices), limits of quantification (0.2-40 ng/L in surface water and 0.2-30 ng/L in drinking water) were calculated. The recoveries at 100 ng/L were >80% for 72% and 79% of the target compounds in surface and drinking waters, respectively. The information obtained from the full method validation has been used to estimate the expanded uncertainty and the uncertainties contributions of the different individual steps of the method for the determination of pharmaceuticals at trace levels in waters. Expanded relative uncertainties ranged from 6% to 23% being the uncertainty associated with reproducibility the main contribution.

Understanding and fighting the medicine counterfeit market

Medicine counterfeiting is a serious worldwide issue, involving networks of manufacture and distribution that are an integral part of industrialized organized crime. Despite the potentially devastating health repercussions involved, legal sanctions are often inappropriate or simply not applied. The difficulty in agreeing on a definition of counterfeiting, the huge profits made by the counterfeiters and the complexity of the market are the other main reasons for the extent of the phenomenon. Above all, international cooperation is needed to thwart the spread of counterfeiting. Moreover effort is urgently required on the legal, enforcement and scientific levels. Pharmaceutical companies and agencies have developed measures to protect the medicines and allow fast and reliable analysis of the suspect products. Several means, essentially based on chromatography and spectroscopy, are now at the disposal of the analysts to enable the distinction between genuine and counterfeit products. However the determination of the components and the use of analytical data for forensic purposes still constitute a challenge. The aim of this review article is therefore to point out the intricacy of medicine counterfeiting so that a better understanding can provide solutions to fight more efficiently against it.

Quantification of doxycycline hyclate in tablets by HPLC-UV method

An accurate, sensitive, precise and rapid gradient reversed-phase high-performance liquid chromatographic method was successfully developed and validated for the determination of doxycycline hyclate in bulk drug and tablets. The best separation was achieved on a 250 × 4.6 mm, 5.0 µm particle size CN Luna column with water + 0.1% TFA-acetonitrile + 0.1% TFA, 60:40 (v/v) as the mobile phase at a flow rate of 1.0 mL/min. Ultraviolet detection was performed at 360 nm at ambient column temperature (25°C). The method was linear over the concentration range of 50-100 µg/mL (r = 0.9999) with limits of detection and quantification of 2.83 and 8.59 µg/mL, respectively. The drug was subjected to oxidation, acid, base and neutral degradation, photolysis and heat as stress conditions. Degradation products were found interfering with the assay of doxycycline hyclate, therefore the method can be regarded as suitable. The method was applied for the determination of doxycycline hyclate in standard and pharmaceutical products, with excellent recoveries. The method can be used for the quality control of doxycycline hyclate.

"For export only" medicines come back to Europe: a RP-LC method for the screening of six glucocorticoids in illegal and counterfeit anti-inflammatory and lightening creams

"For export only" anti-inflammatory and lightening creams are medicinal products sold in African countries for their skin whitening action. In the last years, Rapid Alerts from European Medicinal Regulatory Agencies evidenced the presence of a large number of illegal and counterfeit anti-inflammatory products advertised for their whitening action on black skin in the European market. These drugs, containing glucocorticoids, are illegally sold in Europe in unauthorized ethno-cosmetics-shops and mainly bought by immigrants. This paper reports a new RP-LC method for the rapid simultaneous screening of six different active ingredients in anti-inflammatory and whitening products (creams, ointment and suspension): betamethasone dipropionate, dexamethasone, fluocinonide, fluocinolone acetonide, clobetasol propionate, methyl-prednisolone acetate. The method was developed and validated in view of its possible application in quality control laboratories, mainly those appointed to the control of illegal/counterfeit medicinal products. The associated measurement uncertainty was calculated from validation data. The method was then applied to the analysis of whitening products obtained from the Italian illegal market.

Estimating uncertainty in analytical procedures based on chromatographic techniques

Chromatographic techniques are very frequently used in analytical procedures for the separation, determination and identification of a wide spectrum of analytes present in samples with complex and sometimes variable matrices. However, the estimation of uncertainty of the final results does not include the uncertainties associated with the actual chromatographic process. In effect, such results cannot always be treated as a reliable source of analytical information. In this paper we present the basic terms, sources of uncertainty, and methods of calculating the combined uncertainty that any presentation of final determinations should include.