Identification of Substandard and Falsified Medicines: Influence of Different Tolerance Limits and Use of Authenticity Inquiries

Prevalence of substandard, falsified, unlicensed and unregistered medicine and its associated factors in Africa: a systematic review

Background

Substandard, falsified, unlicensed, and unregistered medicines pose significant risks to public health in developed and developing countries. This systematic review provides an overview of the prevalence of substandard, falsified, unlicensed, and unregistered medicine and its associated factors in Africa.

Methods

Articles published from April 2014 to March 2024 were searched in Google Scholar, Science Direct, PubMed, MEDLINE, and Embase. The search strategy focused on open-access articles published in peer-reviewed scientific journals and studies exclusively conducted in African countries. The quality of the studies was assessed according to the Medicine Quality Assessment Reporting Guidelines (MEDQUARG). This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA).

Results

Of the 27 studies, 26 had good methodological quality after a quality assessment. Of the 7508 medicine samples, 1639 failed at least one quality test and were confirmed to be substandard/falsified medicines. The overall estimated prevalence of substandard/falsified medicines in Africa was 22.6% (1718/7592). The average prevalence of unregistered medicines was 34.6% (108/312). Antibiotics, antimalarial, and antihypertensive medicines accounted for 44.6% (712/1596), 15.6% (530/3530), 16.3% (249/1530), and 16.3% (249/1530), respectively. Approximately 60.7% (91/150) were antihelmintic and antiprotozoal medicines. Poor market regulatory permission, Free trade zones, poor registration, high demand, and poor importation standards contribute to the prevalence of these problems.

Conclusion/Recommendations

Substandard, falsified, and unregistered medicines are highly prevalent in Africa, and attention has not been paid to the problem. Antibiotics, antimalarial, anthelmintic, and antiprotozoal are the most commonly reported substandard, falsified, and unregistered medicines. A consistent supply of high-quality products, enhancement of registration, market regulatory permission, and importation standards are essential to counter the problems in Africa. Preventing these problems is the primary duty of every responsible nation to save lives.

Quality of Essential Medicines from Different Sources in Enugu and Anambra, Nigeria

This study investigated the quality of 13 essential medicines in the states of Enugu and Anambra, Nigeria. A total of 260 samples were purchased from licensed pharmaceutical manufacturers and wholesalers and from vendors in pharmaceutical markets with unclear licensing status. Samples were analyzed for identity, content, and dissolution according to the United States Pharmacopeia (USP) 42 monographs. Forty-five samples of this study could be examined for authenticity with the Mobile Authentication Service scheme of the Nigerian National Agency for Food and Drug Administration and Control. Out of all samples, 25.4% did not comply with the USP 42 specifications. Strikingly, 21 out of 22 dexamethasone tablet samples (95%) were out of specification (OOS). Nine out of 19 glibenclamide samples (47%) failed dissolution testing, and 7 out of 17 cotrimoxazole samples (41%) failed assay testing. Medicines against noncommunicable diseases showed a slightly higher percentage of OOS samples than anti-infectives (21.2% versus 17.6%). The rates of OOS samples were similar in medicines stated to be produced in Nigeria, India, and China but were very different between individual manufacturers from each of these countries of origin. Therefore, prequalification of products, manufacturers, and suppliers are very important for quality assurance in medicine procurement. Unexpectedly, the total proportions of OOS samples were similar from licensed vendors (25.2%) and from markets (25.5%). Four samples (1.5%), all collected in markets, were clearly falsified and did not contain the declared active pharmaceutical ingredients. The proportion of falsified medicines was found to be lower than frequently reported in the media for Nigeria.

In-Field Implementation of Near-Infrared Quantitative Methods for Analysis of Medicines in Tropical Environments

Near-infrared (NIR) spectroscopy is actually a well-established technique that demonstrates its performance in the frame of detection of poor-quality medicines. The use of low-cost handheld NIR spectrophotometers in low-resource contexts can allow an inexpensive and more rapid detection compared to laboratory methods. Considering these points, it was decided to develop, validate, and transfer methods for the quantification of ciprofloxacin and metronidazole tablet samples using a NIR handheld spectrophotometer in transmission mode (NIR-M-T1) coupled to chemometrics such as partial least squares regression (PLSR) algorithm. All of the models were validated with the total error approach using an accuracy profile as a decision tool, with ±10% specifications and a risk α set at 5%. Quantitative PLSR models were first validated in Belgium, which is a temperate oceanic climate zone. Second, they were transferred to Cameroon, a tropical climate zone, where issues regarding the prediction of new validation series with the initial models were highlighted. Two augmentation strategies were then envisaged to make the predictive models robust to environmental conditions, incorporating the potential variability linked to environmental effects in the initial calibration sets. The resulting models were then used for in-field analysis of ciprofloxacin and metronidazole tablet samples collected in three cities in Cameroon. The contents results obtained for each sample with the two strategies were close and not statistically different. Nevertheless, the first one is easier to implement and the second is the best regarding model diagnostic measures and accuracy profiles. Two samples were found to be noncompliant in terms of content, and these results were confirmed using high-performance liquid chromatography taken as the reference method.

Prevalence of Poor Quality Ciprofloxacin and Metronidazole Tablets in Three Cities in Cameroon

Quality is one of the essential components of medicines and needs to be ensured to preserve the population's health. This can be achieved through post-marketing quality control of medicines and is one of the most important duties of national regulatory authorities. In collaboration with the Cameroonian National Drug Quality Control and Valuation Laboratory, the decision was made to initiate a prevalence study to assess the quality of antiinfective medicines in Cameroon. A total of 150 samples of ciprofloxacin tablets and 142 samples of metronidazole tablets were collected from 76 licensed pharmacies and 75 informal vendors in three cities in Cameroon using a random strategy wherever possible and a mystery shopper approach. Three tests were carried out on each of the samples. Visual inspection allowed to find two falsified samples (0.7%) due to lack of information about the manufacturing company, and five more samples (1.7%) were deemed to be substandard due to flaws in the product. An additional 13 samples (4.5%) failed disintegration testing, and six (2.1%) others failed high-performance liquid chromatography assay testing due to insufficient active pharmaceutical ingredient (API) content. All samples were found to contain some API. A prevalence of 7.9% substandard or falsified (SF) medicines was found. Moreover, the prevalence of outlets selling SF medicines was greater in the informal sector (26.7%) than in the formal sector (2.6%). Although the prevalence of SF medicines found was low, efforts need to be made by national regulatory authorities to monitor the pharmaceutical market more closely.

Burden of and factors associated with poor quality antibiotic, antimalarial, antihypertensive and antidiabetic medicines in Malawi

OBJECTIVE

To assess the prevalence and factors associated with substandard and falsified (SF) medicines among antibiotic, antimalarial, antihypertensive and antidiabetic medicines in Malawi.

METHODS

We conducted a cross-sectional study in 23 public, faith-based and private health facilities in Zomba, Machinga and Nsanje districts. We analyzed oral medicine samples of commonly used medicines among antibiotics, antimalarial, antihypertensive and antidiabetics in accordance with Malawi Essential Medicines List and local treatment guidelines. These medicines were subjected to visual inspection for any defects and screening for the content of active pharmaceutical ingredient and disintegration of dosage units. Samples that failed during screening and at least 10% of those that passed were subjected to pharmacopeia assay and dissolution test for confirmation. We used thin layer chromatography and disintegration test methods provided in the Global Pharma Health Fund minilab® for the screening purposes. We conducted confirmatory test using High-Performance Liquid Chromatography (HPLC) or ultra-violet/visible spectrophotometer and dissolution.

RESULTS

Of the 293 medicine samples collected, 14.3% were SF medicines. Among the SF medicines were 12.5% of Amlodipine (1/8), 19.2% of Amoxicillin (5/26), 72.2% of Atenolol (8/11), 21.2% of Ciprofloxacin (7/33), 14.3% of Enalapril (1/7), 44.4% of Flucloxacillin (4/9), and 35.7% of sulfadoxine/ pyrimethamine (10/28). Medicine quality was associated with therapeutic medicine class, stated origin of manufacturer, primary packaging material and geographical location. Antimalarial and antidiabetic medicines were of better quality as compared to antibiotics, odds ratio OR 4.2 (95% CI 1.7-9.49), p < 0.002 and OR 5.6 (95% CI 1.21-26.09), p < 0.028 respectively. In terms of stated country of origin, the prevalence of SF medicines was 30% (15/50), 33% (9/27), 26.7% (4/15) and 6.6% (8/122) for medicines stated to be manufactured in Malawi, China, Kenya and India respectively.

CONCLUSION

This study presents the first findings on the assessment of quality of medicines since the establishment of the national pharmacovigilance center in 2019 in Malawi. It is revealed that the problem of SF medicines is not improving and hence the need for further strengthening of quality assurance systems in Malawi.

An open-source smartphone app for the quantitative evaluation of thin-layer chromatographic analyses in medicine quality screening

Substandard and falsified medicines present a serious threat to public health. Simple, low-cost screening tools are important in the identification of such products in low- and middle-income countries. In the present study, a smartphone-based imaging software was developed for the quantification of thin-layer chromatographic (TLC) analyses. A performance evaluation of this tool in the TLC analysis of 14 active pharmaceutical ingredients according to the procedures of the Global Pharma Health Fund (GPHF) Minilab was carried out, following international guidelines and assessing accuracy, repeatability, intermediate precision, specificity, linearity, range and robustness of the method. Relative standard deviations of 2.79% and 4.46% between individual measurements were observed in the assessments of repeatability and intermediate precision, respectively. Small deliberate variations of the conditions hardly affected the results. A locally producible wooden box was designed which ensures TLC photography under standardized conditions and shielding from ambient light. Photography and image analysis were carried out with a low-cost Android-based smartphone. The app allows to share TLC photos and quantification results using messaging apps, e-mail, cable or Bluetooth connections, or to upload them to a cloud. The app is available free of charge as General Public License (GPL) open-source software, and interested individuals or organizations are welcome to use and/or to further improve this software.

Surveillance for substandard and falsified medicines by local faith-based organizations in 13 low- and middle-income countries using the GPHF Minilab

This study evaluates the use of the Global Pharma Health Fund (GPHF) Minilab for medicine quality screening by 16 faith-based drug supply organizations located in 13 low- and middle-income countries. The study period included the year before the COVID-19 pandemic (2019) and the first year of the pandemic (2020). In total 1,919 medicine samples were screened using the GPHF Minilab, and samples showing serious quality deficiencies were subjected to compendial analysis in fully equipped laboratories. Thirty-four (1.8%) of the samples were found not to contain the declared active pharmaceutical ingredient (API), or less than 50% of the declared API, or undeclared APIs, and probably represented falsified products. Fifty-four (2.8%) of the samples were reported as substandard, although the true number of substandard medicines may have been higher due to the limited sensitivity of the GPHF Minilab. The number of probably falsified products increased during the COVID-19 pandemic, especially due to falsified preparations of chloroquine; chloroquine had been incorrectly advocated as treatment for COVID-19. The reports from this project resulted in four international WHO Medical Product Alerts and several national alerts. Within this project, the costs for GPHF Minilab analysis resulted as 25.85 € per sample. Medicine quality screening with the GPHF Minilab is a cost-effective way to contribute to the global surveillance for substandard and falsified medical products.

A feasibility study on the use of a pocket-sized NIR spectrometer and multivariate algorithm to distinguish expired drugs from unexpired ones

An onsite technique for determining drug integrity in sub-Saharan Africa is needed to ensure drug integrity and enhance public health. This current study presents the application of handheld NIR spectroscopic and multivariate techniques for the accurate identification of unexpired drugs from expired ones. A total of 150 drugs comprising 75 drug samples each of antimalarial (40 unexpired and 35 expired) and antibiotics (40 unexpired and 35 expired) were used in the study. Principal component (PC) analysis was used to extract relevant information from the spectral fingerprint and pre-processed using different techniques comparatively to observe the best cluster trends. The performance of three multivariate algorithms: RF, SVM, and PLS-DA were compared after optimization by cross-validation. The results revealed that SVM and PLS-DA were superior with an identification rate for both antimalarial and antibiotic authenticity prediction above 98% at 5 PCs in both the prediction set and calibration set. For simultaneous prediction of expired and unexpired drugs, we achieved a 100% identification rate. Generally, the results show that handheld NIR spectrometers coupled with smartphone devices could successfully be used to identify unexpired antimalarial and antibiotic drugs from expired antimalarial and antibiotic drugs for effective quality assurance in poor-resource countries. This offers positive feasibility for an affordable and user-friendly approach to reducing drug fraud in Africa.

Characterizing Medicine Quality by Active Pharmaceutical Ingredient Levels: A Systematic Review and Meta-Analysis across Low- and Middle-Income Countries

Substandard and falsified medicines are often reported jointly, making it difficult to recognize variations in medicine quality. This study characterized medicine quality based on active pharmaceutical ingredient (API) amounts reported among substandard and falsified essential medicines in low- and middle-income countries (LMICs). A systematic review and meta-analysis was conducted using PubMed, supplemented by results from a previous systematic review, and the Medicine Quality Scientific Literature Surveyor. Study quality was assessed using the Medicine Quality Assessment Reporting Guidelines (MEDQUARG). Random-effects models were used to estimate the prevalence of medicines with < 50% API. Among 95,520 medicine samples from 130 studies, 12.4% (95% confidence interval [CI]: 10.2-14.6%) of essential medicines tested in LMICs were considered substandard or falsified, having failed at least one type of quality analysis. We identified 99 studies that reported API content, where 1.8% (95% CI: 0.8-2.8%) of samples reported containing < 50% of stated API. Among all failed samples (N = 9,724), 25.9% (95% CI: 19.3-32.6%) reported having < 80% API. Nearly one in seven (13.8%, 95% CI: 9.0-18.6%) failed samples were likely to be falsified based on reported API amounts of < 50%, whereas the remaining six of seven samples were likely to be substandard. Furthermore, 12.5% (95% CI: 7.7-17.3%) of failed samples reported finding 0% API. Many studies did not present a breakdown of actual API amount of each tested sample. We offer suggested improved guidelines for reporting poor-quality medicines. Consistent data on substandard and falsified medicines and medicine-specific tailored interventions are needed to ensure medicine quality throughout the supply chain.