Quality Testing of Artemisinin-Based Antimalarial Drugs in Myanmar

New sesquiterpenoids from Biscogniauxia sp

Five new sesquiterpenoids, including a campherenane-type (1), a bergamotane-type (2), a drimane-type (3), and two bisabolane-type (5-6) sesquiterpenoids have been isolated from Biscogniauxia sp. 71-10-1-1. Their structures were determined by spectroscopic analyses, quantum chemical ECD calculations,13C chemical shifts calculations, and X-ray crystallography. This is the first report of campherenane-type and drimane-type sesquiterpenoids from Biscogniauxia. Furthermore, the anti-inflammatory assays of all compounds are evaluated, and the results showed that compounds 3 and 7 exhibited the effects against the production of the pro-inflammatory cytokine TNF-α.

Zero malaria: a mirage or reality for populations of sub-Saharan Africa in health transition

The global burden of malaria continues to be a significant public health concern. Despite advances made in therapeutics for malaria, there continues to be high morbidity and mortality associated with this infectious disease. Sub-Saharan Africa continues to be the most affected by the disease, but unfortunately the region is burdened with indigent health systems. With the recent increase in lifestyle diseases, the region is currently in a health transition, complicating the situation by posing a double challenge to the already ailing health sector. In answer to the continuous challenge of malaria, the African Union has started a "zero malaria starts with me” campaign that seeks to personalize malaria prevention and bring it down to the grass-root level. This review discusses the contribution of sub-Saharan Africa, whose population is in a health transition, to malaria elimination. In addition, the review explores the challenges that health systems in these countries face, that may hinder the attainment of a zero-malaria goal.

Malaria Research for Tailored Control and Elimination Strategies in the Greater Mekong Subregion

The malaria landscape in the Greater Mekong Subregion has experienced drastic changes with the ramp-up of the control efforts, revealing formidable challenges that slowed down the progress toward malaria elimination. Problems such as border malaria and cross-border malaria introduction, multidrug resistance in Plasmodium falciparum, the persistence of Plasmodium vivax, the asymptomatic parasite reservoirs, and insecticide resistance in primary vectors require integrated strategies tailored for individual nations in the region. In recognition of these challenges and the need for research, the Southeast Asian International Center of Excellence for Malaria Research has established a network of researchers and stakeholders and conducted basic and translational research to identify existing and emerging problems and develop new countermeasures. The installation of a comprehensive disease and vector surveillance system at sentinel sites in border areas with the implementation of passive/active case detection and cross-sectional surveys allowed timely detection and management of malaria cases, provided updated knowledge for effective vector control measures, and facilitated the efficacy studies of antimalarials. Incorporating sensitive molecular diagnosis to expose the significance of asymptomatic parasite reservoirs for sustaining transmission helped establish the necessary evidence to guide targeted control to eliminate residual transmission. In addition, this program has developed point-of-care diagnostics to monitor the quality of artemisinin combination therapies, delivering the needed information to the drug regulatory authorities to take measures against falsified and substandard antimalarials. To accelerate malaria elimination, this program has actively engaged with stakeholders of all levels, fostered vertical and horizontal collaborations, and enabled the effective dissemination of research findings.

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.

Assessment of quantitative and semi-quantitative biological test methods of artesunate in vitro

Artesunate is the current most potent antimalarial drug widely used for the treatment of malaria. Considering the emergence of artemisinin resistance, several situations may require a simple method for artesunate quantification. We thus developed a quantitative and a semi-quantitative biological method for the determination of artesunate in liquid samples. The tests are based on the measurement of samples’ antimalarial activity on Plasmodium falciparum 3D7 using a modified SYBR Green I drug susceptibility test. For the quantitative test, we established a standard curve that resulted from a dose–response curve and evaluated its performances using controls samples. Whereas the linear regression analysis between artesunate concentration and antimalarial activity showed promising results (linearity range 1.5–24.6 ng/mL, r² = 0.9373), we found that artesunate content of the controls was significantly overestimated (p = 0.0313). For the semi-quantitative test, we compared the antimalarial activities of samples collected during permeation studies of artesunate to that of a reference (artesunate IC₅₀) by statistical analysis. We demonstrated that antimalarial activities of samples from permeation tests using a powder formulation of artesunate were greater than those of samples from tests using a solution formulation. Bioassays can be simple techniques to assess artesunate in liquid samples, particularly in resource-limited settings. Comparison with reference methods is still recommended when accurate drug quantification is required.

Plasmodium falciparum resistance to ACTs: Emergence, mechanisms, and outlook

Emergence and spread of resistance in Plasmodium falciparum to the frontline treatment artemisinin-based combination therapies (ACTs) in the epicenter of multidrug resistance of Southeast Asia threaten global malaria control and elimination. Artemisinin (ART) resistance (or tolerance) is defined clinically as delayed parasite clearance after treatment with an ART drug. The resistance phenotype is restricted to the early ring stage and can be measured in vitro using a ring-stage survival assay. ART resistance is associated with mutations in the propeller domain of the Kelch family protein K13. As a pro-drug, ART is activated primarily by heme, which is mainly derived from hemoglobin digestion in the food vacuole. Activated ARTs can react promiscuously with a wide range of cellular targets, disrupting cellular protein homeostasis. Consistent with this mode of action for ARTs, the molecular mechanisms of K13-mediated ART resistance involve reduced hemoglobin uptake/digestion and increased cellular stress response. Mutations in other genes such as AP-2μ (adaptor protein-2 μ subunit), UBP-1 (ubiquitin-binding protein-1), and Falcipain 2a that interfere with hemoglobin uptake and digestion also increase resistance to ARTs. ART resistance has facilitated the development of resistance to the partner drugs, resulting in rapidly declining ACT efficacies. The molecular markers for resistance to the partner drugs are mostly associated with point mutations in the two food vacuole membrane transporters PfCRT and PfMDR1, and amplification of pfmdr1 and the two aspartic protease genes plasmepsin 2 and 3. It has been observed that mutations in these genes can have opposing effects on sensitivities to different partner drugs, which serve as the principle for designing triple ACTs and drug rotation. Although clinical ACT resistance is restricted to Southeast Asia, surveillance for drug resistance using in vivo clinical efficacy, in vitro assays, and molecular approaches is required to prevent or slow down the spread of resistant parasites.

In vitro growth competition experiments that suggest consequences of the substandard artemisinin epidemic that may be accelerating drug resistance in P. falciparum malaria

Over the past decade, artemisinin (ART)-combination therapies (ACTs) have shown declining efficacy within Southeast Asia (SEA). These resistance-like phenomena manifest as a delayed clearance phenotype (DCP) in some patients treated with ACTs. ACTs are currently the recommended treatment for P. falciparum infections by the World Health Organization (WHO), and they are our last line of defense to effectively treat all strains of malaria. Acceleration of antimicrobial resistance (AMR) is often theorized to be exacerbated by the use of subtherapeutic dosages of drugs ("substandard" drug), which for ACTs has been well documented over the last decade. Troublingly, in 2017, the WHO estimated that nearly 1 in 10 medical products tested in low- and middle-income countries failed to meet quality standards. We have developed a tissue culture-based approach for testing possible connections between substandard treatment and the spread of ACT resistant blood stage forms of P. falciparum. Via sequencing of pfk13, a molecular marker that is predictive for ART resistance (ARTR), we monitor competition of sensitive vs resistant strains over time and under various conditions and define conditions that favor emergence of ARTR parasites. Our findings help to define the conditions under which substandard drug treatments might favor the proliferation of mutant PfK13-mediated drug resistant strains over drug sensitive.

Sesquiterpenoids from Cultures of the Basidiomycetes Irpex lacteus

Eight previously undescribed sesquiterpenoids, tremutins A-H (1-8), together with three known ones (9-11), were isolated from cultures of the basidiomycetes Irpex lacteus. Structures of the new compounds together with absolute configurations were elucidated on the basis of extensive spectroscopic methods, as well as single-crystal X-ray diffractions and equivalent circulating density calculations. Compounds 1 and 2 possess an unusual 6/7-fused ring system that might be derived from a tremulane framework. Compounds 3-7 and 9-11 are tremulane sesquiterpenoids of which 4 and 5 are the first tremulane examples with a 1,2-epoxy moiety to be reported. Compounds 6, 7, 10, and 11 possess weak activities to several human cancer cell lines. Compound 8 shows a weak inhibitory effect on NO production with a half maximal inhibitory concentration (IC₅₀) value of 22.7 μM. Compound 1 inhibits the lipopolysaccharide (LPS)-induced proliferation of B lymphocyte cells with an IC₅₀ value of 22.4 μM, while 2 inhibits concanavalin A (Con A)-induced T cell proliferation and LPS-induced B lymphocyte cell proliferation with IC₅₀ values of 16.7 and 13.6 μM, respectively.

A review on the latest advances in extraction and analysis of artemisinin

INTRODUCTION

Artemisinin (1), a well-known natural antimalarial drug, is a sesquiterpene lactone that contains a unique peroxide bridge. Since its discovery, the amount of research into the analysis of artemisinin has increased considerably, and it has been further intensified since the Noble Prize win by Tu Youyou in the year 2015 for the discovery of artemisinin.

OBJECTIVE

To review literature on the extraction and analysis of artemisinin, published during 2017-present, and to present an appraisal of those methods.

METHODOLOGY

Extensive literature search was carried out which involved, but not limited to, the use of, various databases, like Web of Knowledge, PubMed and Google Scholar, and relevant published materials including published books. The keywords used, in various combinations, with artemisinin being present in all combinations, in the search were artemisinin, Artemisia annua, analysis, extraction, quantitative, qualitative and quality control.

RESULTS

During the period covered in this review, several methods of analysis of artemisinin have been reported, the most of which were liquid chromatography (LC)-based methods. However, the use of new methods like near-infrared analysis, fluorometirc analysis and molecular imprinting, and a significant increase in the use of computational tools have been observed. Mainly several methods involving supercritical fluid extraction and ultrasound-assisted extraction of artemisinin have dominated the extraction area.

CONCLUSIONS

Newer analytical tools, as well as improved protocols for the known analytical tools, for qualitative and quantitative determination of artemisinin (1), have been made available by various researchers during the period covered by this review. Supercritical fluid extraction and ultrasound-assisted extraction are still the methods of choice for extraction of artemisinin.

Development of a lateral flow dipstick for simultaneous and semi-quantitative analysis of dihydroartemisinin and piperaquine in an artemisinin combination therapy

Dihydroartemisinin (DHA) and piperaquine (PPQ) are two drugs used in an artemisinin-based combination therapy (ACT). The circulation of counterfeit antimalarial drugs demands the development of simple, point-of-care (POC) tests for monitoring drug quality. Here we aimed to design an antibody-based lateral flow dipstick assay for simultaneous quality control of DHA and PPQ. To obtain a monoclonal antibody (mAb) for PPQ, one structural unit of the symmetric PPQ molecule was used to derive a carboxylic acid for linkage to a carrier protein as immunogen. Screening of hybridoma cells identified an mAb 4D112B2 that reacted with the PPQ-based immunogen. A highly-sensitive icELISA was designed based on this mAb, which showed 50% inhibition concentration of PPQ at 1.66 ng/mL and a working range of 0.35 - 7.40 ng/mL. The mAb showed 10.2, 15.9 and 30.4% cross reactivity to hydroxychloroquine sulfate, chloroquine and amodiaquine, respectively. No cross reactivity was observed to lumefantrine, mefloquine artemisinin and its derivatives. Using our previous DHA dipstick design, a lateral flow dipstick for simultaneous analysis of PPQ and DHA was developed. The indicator ranges for PPQ and DHA were 2 - 5 μg/mL and 250 - 500 ng/mL, respectively. The dipstick was used to semi-quantitatively analyze PPQ and DHA content in commercial ACT drugs, which produced agreeable results to those determined by high-performance liquid chromatography. This combination dipstick makes it a potential POC device for quality control of the two active ingredients in a commonly used ACT.

Prevalence and Estimated Economic Burden of Substandard and Falsified Medicines in Low- and Middle-Income Countries: A Systematic Review and Meta-analysis

IMPORTANCE

Substandard and falsified medicines burden health systems by diverting resources to ineffective or harmful therapies, causing medical complications and prolonging illnesses. However, the prevalence and economic impact of poor-quality medicines is unclear.

OBJECTIVE

To conduct a systematic review and meta-analysis to assess the prevalence and estimated economic burden of substandard and falsified essential medicines in low- and middle-income countries.

DATA SOURCES

Five databases (PubMed, EconLit, Global Health, Embase, and Scopus) were searched from inception until November 3, 2017.

STUDY SELECTION

Publications were assessed to determine whether they examined medicine quality and the prevalence and/or economic burden of substandard and falsified medicines in low- and middle-income countries. Studies with a sample size of 50 or more were included in the meta-analysis.

DATA EXTRACTION AND SYNTHESIS

The study is registered in PROSPERO and reported via the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Study quality was assessed using an adapted Medicine Quality Assessment Reporting Guidelines scoring metric. Multiple reviewers conducted the data extraction and quality assessment independently.

MAIN OUTCOMES AND MEASURES

Prevalence and/or estimated economic impact of substandard and falsified medicines.

RESULTS

Two hundred sixty-five studies that estimated the prevalence of poor-quality essential medicines in low- and middle-income countries were identified. Among 96 studies that tested 50 samples or more (67 839 total drug samples), overall prevalence of poor-quality medicines was 13.6% (95% CI, 11.0%-16.3%), with regional prevalence of 18.7% in Africa (95% CI, 12.9%-24.5%) and 13.7% in Asia (95% CI, 8.2%-19.1%). Of studies included in the meta-analysis, 19.1% (95% CI, 15.0%-23.3%) of antimalarials and 12.4% (95% CI, 7.1%-17.7%) of antibiotics were substandard or falsified. Eight approximations of the economic impact, focused primarily on market size, with poor or undisclosed methods in estimation were identified, ranging from $10 billion to $200 billion.

CONCLUSIONS AND RELEVANCE

Poor-quality essential medicines are a substantial and understudied problem. Methodological standards for prevalence and rigorous economic studies estimating the burden beyond market size are needed to accurately assess the scope of the issue and inform efforts to address it. Global collaborative efforts are needed to improve supply-chain management, surveillance, and regulatory capacity in low- and middle-income countries to reduce the threat of poor-quality medicines.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42017080266.

Development of monoclonal antibody-based immunoassays for quantification and rapid assessment of dihydroartemisinin contents in antimalarial drugs

Dihydroartemisinin (DHA) is one of the artemisinin derivatives widely used in artemisinin-based combination therapies (ACTs) for malaria treatment. The availability of a point-of-care device for estimation of DHA quantity would allow a quick quality assessment of the DHA-containing drugs. In this study, 9-O-succinylartemisinin was obtained from microbial fermentation of artemisinin, which was hydrogenated to 9-O-succinyldihydroartemisinin as the hapten for DHA. A monoclonal antibody (mAb), designated as 2G₁1G₄, was identified after screening the hybridoma library, which showed 52.3% cross reactivity to artemisinin, but low or no cross reactivity to artesunate, artemether, and several ACTs partner drugs. Based on this mAb, a highly-sensitive, indirect competitive enzyme-linked immunosorbent assay was designed, which showed 50% inhibition concentration of DHA at 1.16 ng/mL, a working range of 0.26-4.87 ng/mL, and limit of detection of 0.18 ng/mL. In addition, a colloidal gold-based lateral flow immunoassay (dipstick) was developed with an indicator range (indicating sensitivity) of 50-100 ng/mL. This dipstick was evaluated for determination of DHA contents in commercial drugs and the results were highly agreeable with those determined by high-performance liquid chromatography.

Effect of artemisinin and neurectomy of pterygoid canal in ovalbumin-induced allergic rhinitis mouse model

Background

Allergic rhinitis (AR), characterized by sneezing, nasal itching and rhinorrhea, affects a large number of population. This study aimed to explore the effects of artemisinin alone or combined with neurectomy of pterygoid canal in ovalbumin-induced AR mouse model and illustrate the underlying mechanisms.

Methods

Allergic symptoms were evaluated to verify inhibitory effect of artemisinin alone or combined with neurectomy of pterygoid canal on AR. Serum levels of histamine, immunoglobulin E (IgE) and inflammatory factors TNF, INF-γ, IL-1β IL-10, IL-4 and IL-5 were measured by ELISA. The mRNA levels of TNF, INF-γ, IL-1β and IL-10 in local lymph nodes were measured by RT-qPCR. The total and phosphorylated levels of ERK and JNK were assessed by Western blot. CD4⁺CD25⁺Foxp3⁺ T (Treg) cells were analyzed by flow cytometry.

Results

Artemisinin significantly relieved the behavior symptoms of AR mice. The administration of artemisinin strikingly suppressed the expression of histamine, IgE and inflammatory factors. An increased Treg cell proportion and inhibited ERK phosphorylation were observed in artemisinin-treated groups as compared to those in the AR group. Moreover, artemisinin plus neurectomy of pterygoid almost abolished the behavioral score increase in AR mice.

Conclusions

These results indicated that artemisinin exhibited anti-allergic effect by inhibiting ERK activation and increasing Treg cell proportion, which subsequently decreased the expressions of allergic mediators. In addition, artemisinin combined with neurectomy of pterygoid showed better efficacy than artemisinin alone.

Electronic supplementary material

The online version of this article (10.1186/s13223-018-0249-6) contains supplementary material, which is available to authorized users.

Pharmaceutical quality assurance of local private distributors: a secondary analysis in 13 low-income and middle-income countries

Introduction

The rapid globalisation of the pharmaceutical production and distribution has not been supported by harmonisation of regulatory systems worldwide. Thus, the supply systems in low-income and middle-income countries (LMICs) remain exposed to the risk of poor-quality medicines. To contribute to estimating this risk in the private sector in LMICs, we assessed the quality assurance system of a convenient sample of local private pharmaceutical distributors.

Methods

This descriptive study uses secondary data derived from the audits conducted by the QUAMED group at 60 local private pharmaceutical distributors in 13 LMICs. We assessed the distributors’ compliance with good distribution practices (GDP), general quality requirements (GQR) and cold chain management (CCM), based on an evaluation tool inspired by the WHO guidelines ’Model Quality Assurance System (MQAS) for procurement agencies'. Descriptive statistics describe the compliance for the whole sample, for distributors in sub-Saharan Africa (SSA) versus those in non-SSA, and for those in low-income countries (LICs) versus middle-income countries (MICs).

Results

Local private pharmaceutical distributors in our sample were non-compliant, very low-compliant or low-compliant for GQR (70%), GDP (60%) and CCM (41%). Only 7/60 showed good to full compliance for at least two criteria. Observed compliance varies by geographical region and by income group: maximum values are higher in non-SSA versus SSA and in MICs versus LICs, while minimum values are the same across different groups.

Conclusion

The poor compliance with WHO quality standards observed in our sample indicates a concrete risk that patients in LMICs are exposed to poor-quality or degraded medicines. Significant investments are needed to strengthen the regulatory supervision, including on private pharmaceutical distributors. An adapted standardised evaluation tool inspired by the WHO MQAS would be helpful for self-evaluation, audit and inspection purposes.

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.