Incompatibility of antimalarial drugs: challenges in formulating combination products for malaria

Lipophilic drugs require more advance formulation, especially if the intention is to make solutions or semisolid formulations. This also accounts for most antimalarial drugs. Although some of these antimalarial drugs are soluble in lipid vehicles, few of them, such as lumefantrine (LF), are also poorly soluble in oily vehicles. Trying to dissolve and formulate LF as a liquid formulation together with other antimalarial drugs is, therefore, a major task. When mixed in solution together with artemether (AR), precipitation occurs, sometimes with LF precipitating out on its own, and sometimes with AR precipitating out alongside LF. In this study, it was hypothesized that the use of fatty acids could lead to enhanced solubility in lipid formulation. Addition of the fatty acid solved the dissolution challenges, making LF soluble for over a year at room temperature (21-23 °C); but further research is needed to test the mechanism of action of the fatty acid. In addition, design of experiments (MODDE® 13) revealed that the amount of fatty acid in the formulation was the only significant factor for LF precipitation.

Anti-Opisthorchis felineus effects of artemisinin derivatives: An in vitro study

BACKGROUND

The drug of choice for the treatment of opisthorchiasis caused by trematodes Opisthorchis viverrini and O. felineus is praziquantel (PZQ), but there is a constant search for new anthelmintics, including those of plant origin. Positive results on the use of artemisinin derivatives against O. viverrini opisthorchiasis have been shown previously, but the effect of these compounds on O. felineus has not been studied. Therefore, here, a comparative analysis of anthelmintic properties of artemisinin derivatives (artesunate [AS], artemether [AM], and dihydroartemisinin [DHA]) was carried out in vitro in relation to PZQ. Experiments were performed on newly excysted metacercariae (NEMs) and adult flukes of O. felineus.

RESULTS

Dose- and time-dependent effects of artemisinin derivatives and of PZQ were assessed in terms of motility and mortality of both NEMs and adult flukes. The most pronounced anthelmintic action was exerted by DHA, whose half-maximal inhibitory concentrations (IC50) of 1.9 (NEMs) and 2.02 µg/mL (adult flukes) were lower than those of PZQ (0.56 and 0.25 µg/mL, respectively). In contrast to PZQ, the effects of DHA and AS were similar when we compared the two developmental stages of O. felineus (NEMs and adult flukes). In addition, AM, AS, and especially DHA at doses of 100 µg/mL disrupted tegument integrity in adult flukes, which was not observed with PZQ.

CONCLUSIONS

Artemisinin derivatives (AS, AM, and DHA) have good anthelmintic efficacy against the trematode O. felineus, and the action of these substances is comparable to (and sometimes better than) the effects of PZQ.

Artemether regulates liver glycogen and lipid utilization through mitochondrial pyruvate oxidation in db/db mice

OBJECTIVES

Diabetes is an important global health problem. The occurrence and development of type 2 diabetes (T2D) involves multiple organs, among which the liver is an important organ. Artemether is a methyl ether derivative of artemisinin and has displayed significant antidiabetic effects. However, its regulation of glucose metabolism is not clearly elucidated. This study explored the effect of artemether on liver mitochondrial pyruvate metabolism.

METHODS

T2D db/db mice were used and grouped into db/db and db/db+Art groups. Lean wild type mice served as control. After artemether intervention for 12 weeks, the respiratory exchange ratio (RER), redox state, relevant serum lipid content, liver glycogen and lipid content, liver insulin and insulin-like growth factor 1 (IGF-1) signal transduction, mitochondrial pyruvate oxidation pathway, fatty acid and glycogen metabolic pathways were evaluated.

RESULTS

This experiment demonstrated that artemether raised RER and enhanced liver mitochondrial pyruvate metabolism in db/db mice. Artemether also reduced serum and urinary lipid peroxidation products and regulated the redox status in liver. The accumulation of liver glycogen in diabetic mice was attenuated, the proportion of lipid content in serum and liver was changed by artemether. The signal pathway associated with liver glycogen metabolism was also regulated by artemether. In addition, artemether increased serum insulin and regulated insulin/IGF-1 signal pathway in liver.

CONCLUSIONS

The present study confirmed that artemether can regulate liver glycogen and lipid utilization in T2D mice, its biological mechanisms were associated with mitochondrial pyruvate oxidation in the liver.

Determine the enzymatic kinetic characteristics of CYP3A4 variants utilizing artemether-lumefantrine

Artemether-lumefantrine is an artemisinin-based combination therapy for the treatment of malaria, which are primarily metabolized by cytochrome P450 3A4. Therapeutic difference caused by gene polymorphisms of CYP3A4 may lead to uncertain adverse side effects or treatment failure. The aim of this study was to evaluate the effect of CYP3A4 gene polymorphism on artemether-lumefantrine metabolism in vitro. Enzyme kinetics assay was performed using recombinant human CYP3A4 cell microsomes. The analytes, dihydroartimisinin and desbutyl-lumefantrine, were detected by ultra-performance liquid chromatography tandem mass spectrometry. The results demonstrated that compared to CYP3A4.1, the intrinsic clearance of CYP3A4.4, 5, 9, 16, 18, 23, 24, 28, 31-34 significantly reduced for artemether (58.5%-93.3%), and CYP3A4.17 almost loss catalytic activity. Simultaneously, CYP3A4.5, 14, 17, 24 for lumefantrine were decreased by 56.1%-99.6%, and CYP3A4.11, 15, 18, 19, 23, 28, 29, 31-34 for lumefantrine was increased by 51.7%-296%. The variation in clearance rate indicated by molecular docking could be attributed to the disparity in the binding affinity of artemether and lumefantrine with CYP3A4. The data presented here have enriched our understanding of the effect of CYP3A4 gene polymorphism on artemether-lumefantrine metabolizing. These findings serve as a valuable reference and provide insights for guiding the treatment strategy involving artemether-lumefantrine.

The pipeline for drugs for control and elimination of neglected tropical diseases: 2. Oral anti-infective drugs and drug combinations for off-label use

In its 'Road map for neglected tropical diseases 2021-2030', the World Health Organization outlined its targets for control and elimination of neglected tropical diseases (NTDs) and research needed to achieve them. For many NTDs, this includes research for new treatment options for case management and/or preventive chemotherapy. Our review of small-molecule anti-infective drugs recently approved by a stringent regulatory authority (SRA) or in at least Phase 2 clinical development for regulatory approval showed that this pipeline cannot deliver all new treatments needed. WHO guidelines and country policies show that drugs may be recommended for control and elimination for NTDs for which they are not SRA approved (i.e. for 'off-label' use) if efficacy and safety data for the relevant NTD are considered sufficient by WHO and country authorities. Here, we are providing an overview of clinical research in the past 10 years evaluating the anti-infective efficacy of oral small-molecule drugs for NTD(s) for which they are neither SRA approved, nor included in current WHO strategies nor, considering the research sponsors, likely to be registered with a SRA for that NTD, if found to be effective and safe. No such research has been done for yaws, guinea worm, Trypanosoma brucei gambiense human African trypanosomiasis (HAT), rabies, trachoma, visceral leishmaniasis, mycetoma, T. b. rhodesiense HAT, echinococcosis, taeniasis/cysticercosis or scabies. Oral drugs evaluated include sparfloxacin and acedapsone for leprosy; rifampicin, rifapentin and moxifloxacin for onchocerciasis; imatinib and levamisole for loiasis; itraconazole, fluconazole, ketoconazole, posaconazole, ravuconazole and disulfiram for Chagas disease, doxycycline and rifampicin for lymphatic filariasis; arterolane, piperaquine, artesunate, artemether, lumefantrine and mefloquine for schistosomiasis; ivermectin, tribendimidine, pyrantel, oxantel and nitazoxanide for soil-transmitted helminths including strongyloidiasis; chloroquine, ivermectin, balapiravir, ribavirin, celgosivir, UV-4B, ivermectin and doxycycline for dengue; streptomycin, amoxicillin, clavulanate for Buruli ulcer; fluconazole and isavuconazonium for mycoses; clarithromycin and dapsone for cutaneous leishmaniasis; and tribendimidine, albendazole, mebendazole and nitazoxanide for foodborne trematodiasis. Additional paths to identification of new treatment options are needed. One promising path is exploitation of the worldwide experience with 'off-label' treatment of diseases with insufficient treatment options as pursued by the 'CURE ID' initiative.

Erythrocyte membrane with CLIPPKF as biomimetic nanodecoy traps merozoites and attaches to infected red blood cells to prevent Plasmodium infection

BACKGROUND

Malaria remains a serious threat to global public health. With poor efficacies of vaccines and the emergence of drug resistance, novel strategies to control malaria are urgently needed.

RESULTS

We developed erythrocyte membrane-camouflaged nanoparticles loaded with artemether based on the growth characteristics of Plasmodium. The nanoparticles could capture the merozoites to inhibit them from repeatedly infecting normal erythrocytes, owing to the interactions between merozoites and heparin-like molecules on the erythrocyte membrane. Modification with a phosphatidylserine-targeting peptide (CLIPPKF) improved the drug accumulation in infected red blood cells (iRBCs) from the externalized phosphatidylserine induced by Plasmodium infection. In Plasmodium berghei ANKA strain (pbANKA)-infected C57BL/6 mice, the nanoparticles significantly attenuated Plasmodium-induced inflammation, apoptosis, and anemia. We observed reduced weight variation and prolonged survival time in pbANKA-challenged mice, and the nanoparticles showed good biocompatibility and negligible cytotoxicity.

CONCLUSION

Erythrocyte membrane-camouflaged nanoparticles loaded with artemether were shown to provide safe and effective protection against Plasmodium infection.

Preparation and application of a specific single-chain variable fragment against artemether

Artemether, an artemisinin derivative, is a component of the commonly used artemisinin-based combination therapy, artemether-lumefantrine. In this study, we cloned the VH and VL genes of a cell line (mAb 2G12E1) producing a monoclonal antibody specific to artemether, and used to construct a recombinant DNA of single-chain variable fragment (scFv). The scFv was constructed into prokaryotic expression vectors pET32a (+), pET22b (+), pGEX-2T, and pMAL-p5x, respectively. However, only the pMAL-p5x/scFv could be induced to express soluble scFv with comparable sensitivity and specificity to that of mAb 2G12E1. Based on the anti-artemether scFv, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed. The 50% of inhibition concentration (IC₅₀) value and the working range based on IC₂₀ to IC₈₀ were 4.33 ng mL^-1 and 1.05-22.65 ng mL^-1, respectively. The artemether content in different drugs were determined by the developed icELISA, and the results were consistent to those determined by ultra performance liquid chromatography (UPLC). The anti-artemether scFv prepared in the current study could be a valuable genetically engineered antibody applied for artemether monitoring and specific binding mechanism studying.

Controlled release starch-lipid implant for the therapy of severe malaria

Parenteral depot systems can provide a constant release of drugs over a few days to months. Poly-(lactic acid) (PLA) and Poly-(lactide-co-glycolide) (PLGA) are the most commonly used polymers in the production of these systems. Finding alternatives to these polymers is of great importance to avoid certain drawbacks of these polymers (e.g. microacidity) and to increase the selection possibilities. In this study, different types of starch in combination with glycerol monostearate (GMS) were developed and investigated for their physicochemical properties and release characteristics. The noninvasive method of electron paramagnetic resonance (EPR) was used to study the release kinetics and mechanisms of nitroxide model drugs. The studies demonstrated the general suitability of the system composed of high amylose starch and GMS to form a controlled release system. For further characterization of the prepared system, formulations with different proportions of starch and GMS, loaded with the antimalarial agents artesunate or artemether were prepared. The implants were characterized with X-ray powder diffraction (XRPD) and texture analysis. The in vitro release studies demonstrated the sustained release of artemether over 6 days from a starch-based implant which matches desired kinetic for the treatment of severe malaria. In summary, a starch-based implant with appropriate mechanical properties was produced that can be a potential candidate for the treatment of severe malaria.

Artemether attenuates renal tubular injury by targeting mitochondria in adriamycin nephropathy mice

Chronic kidney disease (CKD) is complex and current treatment remains limited. As we know, glomerular injury plays a dominant role in kidney disease progression. However, accumulating evidence demonstrated that renal tubules, rather than being victims or bystanders, are major initiators in renal fibrosis progression. Renal tubules are rich in mitochondria and mitochondrial dysfunction may participate in renal tubular phenotypic changes and ultimately promote renal fibrosis. Previous studies have proved that artemether displayed renal protective effects, but the mechanisms remain unclear. In this experiment, we showed that artemether reduced urinary protein/creatinine ratio and attenuated renal tubular injury. Both in vivo and in vitro results indicated that artemether could restore renal tubular phenotypic alterations. Meanwhile, the unbalanced expressions of Bax and Bcl-xL in renal tubules were restored by artemether. In addition, artemether also regulated mitochondrial pyruvate metabolism, increased mitochondrial biogenesis, and improved mitochondrial function. Taken together, this study suggested that artemether could attenuate renal tubular injury by regulating mitochondrial biogenesis and function. It has great potential to be translated to the clinic as a therapeutic agent for treating kidney diseases, especially those associated with renal tubular injury.

Artemether and aspterric acid induce pancreatic α cells to transdifferentiate into β cells in zebrafish

BACKGROUND AND PURPOSE

Recently, the anti-malarial drug, artemether, and the neurotransmitter γ-aminobutyric acid (GABA) were identified to convert α cells into β-like cells in vivo. However, some of these observations were challenged by other studies. To help address the controversy, we took advantage of zebrafish as a model to perform this study.

EXPERIMENTAL APPROACH

Firstly, we performed a small molecule screening for artemether and its skeleton analogs. Secondly, we used the Cre-LoxP system for lineage tracing to indicate the conversion of α cells into β cells in vivo. The stable transgenic ins2:eGFP αTC1-6 cell line were used for evaluation of α cell transdifferentiation in vitro. We further used multiple zebrafish transgenic and mutation lines to demonstrate β-cell differentiation, β-cell ablation and α-cell hyperplasia in this study.

KEY RESULTS

We showed that artemether and another sesquiterpene, aspterric acid, induced α cell transdifferentiation into β cells, both in zebrafish as well as using αTC1-6 cells. Furthermore, these two compounds also converted α cells into β cells when β cells were lost or α cells were hyperplastic in zebrafish. Unlike the previous report, the conversion of α cells to β cells was mediated by increasing Pax4 expression, but not suppression of Arx expression.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that in zebrafish and αTC1-6 cells, both artemether and aspterric acid induce α cell transdifferentiation. Our data, along with those of Li et al. (2017), suggested that artemether and aspterric acid were able to induce α cell transdifferentiation, at least in zebrafish and αTC1-6 cells.

Pharmacokinetic properties of the antimalarial combination therapy artemether-lumefantrine in normal-weight, overweight and obese healthy male adults

The component drugs in the widely used antimalarial artemisinin combination therapy artemether-lumefantrine are lipophilic, with the possibility that recommended fixed doses in adults may lead to subtherapeutic concentrations and consequent treatment failure in overweight/obese individuals with malaria. The aim of this study was to investigate the pharmacokinetic properties of artemether, lumefantrine and their active metabolites dihydroartemisinin and desbutyl-lumefantrine in 16 normal-weight, overweight and obese healthy male volunteers [body mass index (BMI) categories ≤25 kg/m², >25-≤30 kg/m² and >30 kg/m², respectively; absolute range 19.3-37.2 kg/m²]. Participants received the conventional six doses of artemether-lumefantrine over 3 days, each dose comprising 80 mg artemether plus 480 mg lumefantrine administered with 6.7 g fat, and blood samples were collected at pre-specified time-points over 14 days. Plasma drug/metabolite concentrations were measured using liquid chromatography-mass spectrometry and included in multi-compartmental population pharmacokinetic models. There was a non-significant trend to a lower area under the plasma concentration-time curve with a higher body weight or BMI for dihydroartemisinin and especially artemether which was attenuated when normalized for mg/kg dose, but this relationship was not evident in the case of the more lipophilic lumefantrine and its metabolite desbutyl-lumefantrine. Simulated Day 7 plasma lumefantrine concentrations were >200 µg/L (the threshold at which Plasmodium falciparum recrudescences are minimized) in all participants. These results indicate that there is no need for artemether-lumefantrine dose modification in overweight and obese patients with malaria.

In vitro effect of artemether-loaded nanostructured lipid carrier (NLC) on Leishmania infantum

Visceral leishmaniasis (VL) is an acute and deadly form of leishmaniasis, caused by Leishmania infantum parasite. Due to the toxicity and side effects of conventional treatment options, such as glucantime and other pentavalent drugs, finding novel drugs with fewer adverse effects is required. Artemether (ART), is one of the derivatives of artemisinin, which was shown to be effective in treating malaria and more recently, leishmaniasis. In this fundamental-applied research, we compared the effect of ART and nanostructure loaded with artemether (NLC-ART) on Leishmania infantum promastigotes and amastigotes, at different concentrations (2.5-5-10-25-50-100 μg/ml) using the MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay method after 24 and 48 h of treatment. Inhibitory concentration (IC50) values (μg/ml) of promastigote and amastigote of L. infantum to ART/ NLC-ART, after 48 h of treatment, were found to be 37.12 / 32.1 and 16.43 / 15.42, respectively. Moreover, we found that (NLC-ART), had the lowest cytotoxicity against the J774 macrophage cell line. Conclusion: The NLC-ART can be a good candidate for the treatment of visceral leishmaniasis.

Artemether-loaded nanostructured lipid carriers: preparation, characterization, and evaluation of in vitro effect on Leishmania major

Background and purpose

Cutaneous leishmaniasis is a global health problem. The discovery of new and highly efficient anti-leishmanial treatments with lower toxicity is globally needed. The current study was carried out to evaluate the anti-leishmanial effects of artemether (ART) and ART-loaded nanostructured lipid carriers (ART-NLCs) against promastigotes and amastigotes of Leishmania major.

Experimental approach

Solvent diffusion evaporation technique was applied to prepare ART-NLCs. These nanoparticles were characterized using a particle size analyzer (PSA), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The antiparasitic activity on amastigote was assessed in J774 cell culture. The drug cytotoxicity on promastigote and macrophage was assessed using the MTT technique after 24 and 48 h and compared with NLCs, ART, and amphotericin B, as the control agents. The selectivity index was calculated for the agents.

Findings/Results

The DLS and PSA techniques confirmed that ART-NLCs were homogenous in size with an average diameter of 101 ± 2.0 nm and span index of 0.9. The ART-NLCs significantly heighten the anti-leishmanial activity of ART (P < 0.001). The IC₅₀ values of ART and ART-NLCs on promastigotes after 24 and 48 h were 76.08, 36.71 and 35.14, 14.81 μg/mL, respectively while they were calculated 53.97, 25.43 and 20.13, 11.92 for amastigotes. Also, ART-NLCs had the lowest cytotoxicity against macrophages. Furthermore, among the agents tested, ART-NLCs had the highest selectivity index.

Conclusion and implications

ART-NLCs had lower cytotoxic effects than ART and amphotericin B, also its selectivity index was significantly higher. Based on the findings of the study, this formulation could be a promising candidate for further research into leishmaniasis treatment.

Comparative effects of artemether and in combination with diminazene aceturate in the treatment of experimental Trypanosoma brucei brucei infection in Wistar rats

This study assessed the effects of artemether and in combination with diminazene aceturate on parasitaemia, weight, haematology and pathology induced by experimentally Trypanosoma brucei brucei infection in Wistar rats. Fifty adult rats comprising 25 each of males and females were assigned into 5 groups of ten rats (five males and five females). Rats in group I was uninfected while groups II-V were infected with T b brucei. Groups II were untreated; III administered diminazene aceturate once; IV and V administered artemether only and in combination with diminazene aceturate respectively for 5 days. Parasitaemia was determined daily, blood was collected for haematology and weight obtained every four days for a period of 32 days. At 24 days post-treatment, rats were humanely euthanized and organs harvested for pathological examination. Results revealed parasitaemia at day 4 post-infection, significant (p < 0.05) decrease in weight, erythrogram and leucogram in all infected rats. Following treatment, there was significant (p < 0.05) decrease in parasitaemia, increased weight gain and improved haematology. Pathological examination revealed significantly (p < 0.05) decreased gross and histopathological lesions in treated groups compared to group II. In conclusion, artemether and in combination with diminazene aceturate produced antitrypanosomal effects against experimental trypanosomosis.

Evaluation of artemisinin derivative artemether as a fluconazole potentiator through inhibition of Pdr5

Antifungal development has gained increasing attention due to its limited armamentarium and drug resistance. Drug repurposing holds great potential in antifungal discovery. In this study, we explored the antifungal activity of artemisinin and its derivatives, dihydroartemisinin, artesunate and artemether. We identified that artemisinins can inhibit the growth of Candida albicans, and can enhance the activity of three commonly used antifungals, amphotericin B, micafungin and fluconazole (FLC), on Candida albicans growth and filamentation. Artemisinins possess stronger antifungal effect with FLC than with other antifungals. Among artemisinins, artemether exhibits the most potent antifungal activity with FLC and can recover the susceptibility of FLC-resistant clinical isolates to FLC treatment. The combinatorial antifungal activity of artemether and FLC is broad-spectrum, as it can inhibit the growth of Candida auris, Candida tropicalis, Candida parapsilosis, Saccharomyces cerevisiae and Cryptococcus neoformans. Mechanistic investigation revealed that artemether might enhance azole efficacy through disrupting the function of Pdr5, leading to intracellular accumulation of FLC. This study identified artemether as a novel FLC potentiator, providing potential therapeutic insights against fungal infection and antifungal resistance.

Artemether confers neuroprotection on cerebral ischemic injury through stimulation of the Erk1/2-P90rsk-CREB signaling pathway

Ischemic stroke is one of the leading causes of death and disability among adults. Despite the economic burden of the disease, available treatment options are still very limited. With the exception of anti-thrombolytics and hypothermia, current therapies fail to reduce neuronal injury, neurological deficits and mortality rates, suggesting that the development of novel and more effective therapies against ischemic stroke is urgent. In the present study, we found that artemether, which has been used in the clinic as an anti-malarial drug, was able to improve the neurological deficits, attenuate the infarction volume and the brain water content in a middle cerebral artery occlusion (MCAO) animal model. Furthermore, artemether treatment significantly suppressed cell apoptosis, stimulated cell proliferation and promoted the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), P90^rsk and cAMP responsive element-binding protein (CREB). Artemether protective effect was attenuated by PD98059, an ERK1/2 inhibitor, administration. Similarly, in oxygen-glucose deprivation/reperfusion (OGD/RP) cell models, artemether pre-treatment induced the suppression of the intracellular ROS, the down-regulation of LDH activity, the reduction of caspase 3 activity and of the apoptosis cell rate and reversed the decrease of mitochondrial membrane potential. As with MCAO animal model, artemether promoted the activation of Erk1/2-P90^rsk-CREB signaling pathway. This effect was blocked by the inhibition or knock-down of ERK1/2. The present study provides evidences of the neuroprotective effect of artemether unravelling its potential as a new therapeutic candidate for the prevention and treatment of stroke.

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Artemether conferred neuroprotection in a middle cerebral artery occlusion (MCAO) animal model.

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Artemether conferred neuroprotection on oxygen-glucose deprivation/reperfusion-induced cell injury model.

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Artemether promoted the activation of Erk1/2-P90^rsk-CREB signaling pathway in vitro and in vivo.

Artemisia annua L. extracts inhibit the in vitro replication of SARS-CoV-2 and two of its variants

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. has been used for millennia in Southeast Asia to treat "fever". Many infectious microbial and viral diseases have been shown to respond to A. annua and communities around the world use the plant as a medicinal tea, especially for treating malaria.

AIM OF THE STUDY

SARS-CoV-2 (the cause of Covid-19) globally has infected and killed millions of people. Because of the broad-spectrum antiviral activity of artemisinin that includes blockade of SARS-CoV-1, we queried whether A. annua suppressed SARS-CoV-2.

MATERIALS AND METHODS

Using Vero E6 and Calu-3 cells, we measured anti SARS-CoV-2 activity against fully infectious virus of dried leaf extracts of seven cultivars of A. annua sourced from four continents. IC50s were calculated and defined as the concentrations that inhibited viral replication by 50%; CC50s were also calculated and defined as the concentrations that kill 50% of cells.

RESULTS

Hot-water leaf extracts based on artemisinin, total flavonoids, or dry leaf mass showed antiviral activity with IC₅₀ values of 0.1-8.7 μM, 0.01-0.14 μg, and 23.4-57.4 μg, respectively. Antiviral efficacy did not correlate with artemisinin or total flavonoid contents of the extracts. One dried leaf sample was >12 years old, yet its hot-water extract was still found to be active. The UK and South African variants, B1.1.7 and B1.351, were similarly inhibited. While all hot water extracts were effective, concentrations of artemisinin and total flavonoids varied by nearly 100-fold in the extracts. Artemisinin alone showed an estimated IC₅₀ of about 70 μM, and the clinically used artemisinin derivatives artesunate, artemether, and dihydroartemisinin were ineffective or cytotoxic at elevated micromolar concentrations. In contrast, the antimalarial drug amodiaquine had an IC₅₀ = 5.8 μM. Extracts had minimal effects on infection of Vero E6 or Calu-3 cells by a reporter virus pseudotyped by the SARS-CoV-2 spike protein. There was no cytotoxicity within an order of magnitude above the antiviral IC₉₀ values.

CONCLUSIONS

A. annua extracts inhibit SARS-CoV-2 infection, and the active component(s) in the extracts is likely something besides artemisinin or a combination of components that block virus infection at a step downstream of virus entry. Further studies will determine in vivo efficacy to assess whether A. annua might provide a cost-effective therapeutic to treat SARS-CoV-2 infections.

Heparin-decorated nanostructured lipid carriers of artemether-protoporphyrin IX-transferrin combination for therapy of malaria

Heme is a prosthetic group of hemoglobin comprising protoporphyrin IX (PPIX) with Fe²⁺. Studies have shown that modulating heme synthesis pathway in Plasmodium could greatly affect the action mechanism and antimalarial effect of artemisinin and its derivatives. Herein, an intraerythrocytic parasite targeted nanostructured lipid carrier (NLC) was developed for potentiation of artemether (ARM) by combination with PPIX and iron-loaded transferrin (holo-Tf). Firstly, ARM and PPIX were co-loaded into NLCs with high entrapment efficiency. Then, a targeting ligand heparin (HP) was electrostatically adsorbed onto the periphery of NLCs, followed by conjugation with holo-Tf to receive the final formulation Tf-HP-NLC/ARM/PPIX. Tf-HP-NLC/ARM/PPIX exhibited nanoscale particle size (~188 nm) and was relatively stable in simulated gastrointestinal fluids and rat plasma. A sustained drug release characteristic was observed in PBS (pH 7.4). In vitro targeting assay confirmed that Tf-HP-NLC/ARM/PPIX could be specifically and efficiently internalized into intraerythrocytic parasites via HP receptor-meditated endocytosis. Furthermore, due to enhanced intraparasitic accumulation and activated mechanism of ARM, the combinational delivery system Tf-HP-NLC/ARM/PPIX showed increased inhibitory activity against Plasmodium falciparum in culture and enhanced antimalarial effect in Plasmodium berghei-infected murine model, suggesting a promising strategy for development of new therapy based on action mechanism of ARM.

Effect of fresh pomegranate juice on the pharmacokinetic profile of artemether: An open-label, randomized, 2- period crossover study in healthy human volunteers

This study was designed to evaluate the effect of fresh pomegranate (Punica granatum L.) juice on the pharmacokinetic profile of artemether in healthy volunteers. A randomized, open-label, crossover study was conducted on healthy subjects (n = 26). Each volunteer received 250 mL of fresh pomegranate juice twice daily for 2 weeks. On day 14, they were administered a single oral dose of artemether (80 mg) with either water or 250 mL of pomegranate juice. Thirteen blood samples were collected up to 12 h and 6 electrocardiograms were recorded. Plasma concentrations of artemether and its metabolite dihydroartemisinin were analyzed by a noncompartmental method using LC-MS/MS. The lower limit of detection (LLOD) and lower limit of quantification (LLOQ) for artemether were estimated as 0.3 and 0.8 ng/mL, respectively, while for dihydroartemisinin it was 0.2 and 0.6 ng/mL, respectively. The pharmacokinetic parameters of artemether and dihydroartemisinin were not significantly altered when co-administered with the fresh pomegranate juice. AUC _(0-∞) was slightly increased from 742 to 859 ng/mL for artemether [geometric mean ratio: 1.14 (95 % CI, 1.08,1.18); P = 0.45] and from 699 to 818 ng/mL for dihydroartemisinin [geometric mean ratio: 1.15 (95 % CI, 1.09, 1.15); P = 0.4]. Difference in C_max for artemether was also statistically non-significant [173 vs 195 ng/mL; geometric mean ratio: 1.09 (95 % CI, 0.91, 1.15); P = 0.61]. Likewise, elimination half-life (t_1/2) for both artemether and dihydroartemisinin remained unchanged (P = 0.43 and 0.31, respectively). In addition, there was no significant difference in t_max for artemether (P = 0.66) and its metabolite (P = 0.65). In conclusion, findings of the present study demonstrated that the administration of pomegranate juice had no significant effect on the pharmacokinetic profile of artemether.

Formulation and evaluation of transdermal nanogel for delivery of artemether

Artemether (ART) is second to artesunate in being the most widely used derivatives of artemisinin in combination therapy of malaria. Nanostructured lipid carrier (NLC) formulations were prepared following our previous report using optimized ART concentration of 0.25 g dissolved in 5% w/v mixture of solid (Gelucire 43/01 and Phospholipon 85G) and liquid (Transcutol) lipids at 90 °C. An aqueous surfactant phase at 90 °C was added (dropwise) under magnetic stirring (1000 rpm) for 5 min. The pre-emulsion was speedily homogenized at 28,000 rpm for 15 min and further probe sonicated at 60% amplitude (15 min). Resultant sample was cooled at room temperature and frozen at - 80 °C prior to lyophilization. The freeze-dried sample was used for solid-state characterization as well as in the formulation of transdermal nanogels using three polymers (Carbopol 971P, Poloxamer 407, and Prosopis africana peel powder) to embed the ART-NLC, using ethanol as a penetration enhancer. Transdermal ART-nanogels were characterized accordingly (physical examination, pH, drug content, rheology, spreadability, stability, particle size and morphology, skin irritation, in vitro and ex vivo skin permeation, and analysis of permeation data), P < 0.05. Results indicated that ART nanogels showed good encapsulation, drug release, pH-dependent swelling, stability, and tolerability. Overall, ART nanogels prepared from Poloxamer 407 showed the most desirable drug permeation, pH, swellability, spreadability, viscosity, and transdermal antiplasmodial properties superior to PAPP-ANG > C971P-ANG. A two-patch/week concurrent application of the studied nanogels could offer 100% cure of malaria as a lower-dose (50 mg ART) patient-friendly regimen devoid of the drug's many side effects.

Choline and PEG dually modified artemether nano delivery system targeting intra-erythrocytic Plasmodium and its pharmacodynamics in vivo

OBJECTIVE

The choline derivative (CD) and polyethylene-glycol (PEG) dually modified artemether (ARM) nanostructured lipid carriers (CD-PEG-ARM-NLC) have been designed to prolong the circulation of ARM in blood, as well as to develop targeting for new permeability pathways (NPPs) and erythrocyte choline carriers (ECCs) that are expressed on the Plasmodium-infected erythrocyte membrane.

SIGNIFICANCE

The CD-PEG-ARM-NLC constructed in this study was found to be able to target endoerythrocytic Plasmodium by increasing the drug concentration and residence time in the infected erythrocytic microenvironment and minimizing toxicity and side effects.

METHODS

CD-PEG-ARM-NLC was prepared using high-pressure homogenization followed by physicochemical characterization. The targeting ability of CD-PEG-NLC to infected erythrocytes probed by coumarin-6 was investigated by using fluorescence microscopy imaging. The SYBR Green I assay for parasite nucleic acid was adapted in order to assess the efficacy of inhibition against parasite growth in vitro. The antimalarial activity of ARM-loaded NLCs was evaluated by a Pearson four-day suppressive test in Pyy265BY-bearing mice.

RESULTS

In vitro imaging indicated that the intracellular delivery of CD-PEG-ARM-NLC was efficiently taken up by the infected erythrocytes via ECCs and NPPs, which could be inhibited by addition of furosemide (an inhibitor of NPPs) and excessive choline (native substrate of ECCs). Moreover, in vitro and in vivo studies that evaluated antimalarial activity suggested that CD-PEG-ARM-NLC exhibited higher antimalarial activity in comparison to ARM-NLC and PEG-ARM-NLC.

CONCLUSION

These findings suggested that choline and PEG dually modified NLC could be promising preparations for the production of hydrophobic antimalarial drugs, particularly for ARM.

Artemisia annua L. extracts inhibit the in vitro replication of SARS-CoV-2 and two of its variants

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. has been used for millennia in Southeast Asia to treat "fever". Many infectious microbial and viral diseases have been shown to respond to A. annua and communities around the world use the plant as a medicinal tea, especially for treating malaria.

AIM OF THE STUDY

SARS-CoV-2 (the cause of Covid-19) globally has infected and killed millions of people. Because of the broad-spectrum antiviral activity of artemisinin that includes blockade of SARS-CoV-1, we queried whether A. annua suppressed SARS-CoV-2.

MATERIALS AND METHODS

Using Vero E6 and Calu-3 cells, we measured anti viral activity SARS-CoV-2 activity against fully infectious virusof dried leaf extracts of seven cultivars of A. annua sourced from four continents. IC50s were calculated and defined as (the concentrations that inhibited viral replication by 50%.) and CC50s (the concentrations that kill 50% of cells) were calculated.

RESULTS

Hot-water leaf extracts based on artemisinin, total flavonoids, or dry leaf mass showed antiviral activity with IC50 values of 0.1-8.7 μM, 0.01-0.14 μg, and 23.4-57.4 μg, respectively. Antiviral efficacy did not correlate with artemisinin or total flavonoid contents of the extracts. One dried leaf sample was >12 years old, yet the hot-water extract was still found to be active. The UK and South African variants, B1.1.7 and B1.351, were similarly inhibited. While all hot water extracts were effective, concentrations of artemisinin and total flavonoids varied by nearly 100-fold in the extracts. Artemisinin alone showed an estimated IC50 of about 70 μM, and the clinically used artemisinin derivatives artesunate, artemether, and dihydroartemisinin were ineffective or cytotoxic at elevated micromolar concentrations. In contrast, the antimalarial drug amodiaquine had an IC50 = 5.8 μM. Extracts had minimal effects on infection of Vero E6 or Calu-3 cells by a reporter virus pseudotyped by the SARS-CoV-2 spike protein. There was no cytotoxicity within an order of magnitude above the antiviral IC90 values.

CONCLUSIONS

A. annua extracts inhibit SARS-CoV-2 infection, and the active component(s) in the extracts is likely something besides artemisinin or a combination of components that block virus infection at a step downstream of virus entry. Further studies will determine in vivo efficacy to assess whether A. annua might provide a cost-effective therapeutic to treat SARS-CoV-2 infections.

Lipid-based nanocarriers co-loaded with artemether and triglycerides of docosahexaenoic acid: Effects on human breast cancer cells

Artemether (ART) was combined with triglyceride of docosahexaenoic acid (DHA) as the lipid-core in nanoemulsions (NE), nanostructured lipid carriers (NLC), and PEG-PLA nanocapsules (NC) formulations, and their effects on human breast cancer cells were evaluated. ART has been extensively used for malaria and has also therapeutic potential against different tumor cells in a repositioning strategy. The concentration-dependent cytotoxicity in vitro was determined in tumor lineages, MDA-MB-231 and MCF-7, and non-tumor MCF-10A cells for free-ART/DHA combination and its formulations. The cells were monitored for viability, effects on cell migration and clonogenicity, cell death mechanism, and qualitative and quantitative cell uptake of nanocarriers. The lipid-nanocarriers showed mean sizes over the range of 110 and 280 nm with monodisperse populations and zeta potential values ranging from -21 to -67 mV. The ART encapsulation efficiencies varied from 57 to 83 %. ART/DHA co-loaded in three different lipid nanocarriers reduced the MDA-MB-231 and MCF-7 viability in a dose-dependent manner with enhanced selectivity toward tumor cell lines. They also reduced clonogenicity and the ability of cells to migrate showing antimetastatic potential in both cell lines and triggered apoptosis in MCF-7 cells. Confocal microscopy and flow cytometry analysis showed that NC, NLC, and NE were rapidly internalized by cells, with higher interaction displayed by NE with MCF-7 cells compared to NC and NLC that was correlated with the strongest NE-fluorescence in cells. Therefore, this study not only demonstrated the value of this new combination of ART/DHA as a new strategy for breast cancer therapy but also showed enhanced cytotoxicity and potential metastatic activity of lipid-based formulations against human breast cancer cells that indicate great potential for pre-clinical and clinical translation.

Development and applications of liquid chromatography-mass spectrometry for simultaneous analysis of anti-malarial drugs in pharmaceutical formulations

The objective of this work was to develop a high-performance liquid chromatographic method coupled with a mass spectrometer (LC-MS) for the simultaneous analysis of artemisinin-based drugs (e.g. artemisinin, dihydroartemisinin, artesunate, artemether) and piperaquine in formulations. Simultaneous separation of the investigated drugs was achieved in 14 min on a C18 column (2.1 mm x 100 mm, particle size 1.8 μm) using a gradient elution of 0.05 % v/v formic acid in water and acetonitrile. MS detection was done in a positive ionization mode using electrospray ionization with acquisition in a single ion monitoring mode. Proper diluent and storage time in an autosampler played significant roles on the quantitation accuracy since the target analytes possessed varied solubility and stability in aqueous and organic solvents. The method was fully validated according to ICH guideline and data showed good linearity (R > 0.999, precision (RSD < 3.89 %) and accuracy (%recovery between 98.5 and 103.7) with low limits of detection (LOD < 24.7 ng/mL) and quantitation (LOQ < 82.40 ng/mL). Validation data indicated that the developed LC-MS method is fit for the intended purpose and was successfully applied to evaluate the drug contents in formulations. Among the tested samples, the percent labeled amounts found were between 93.1 and 105.0 % and one supplement capsule contained 0.039 %w/w of artemisinin. The newly developed method could benefit both the quality control departments in pharmaceutical industries and the authorities working on falsified drug problems since official methods for the analysis of these drugs are not available in pharmacopoeias. The method is fast and environmentally friendly due to the requirement of less chemicals and production of less wastes.

Development of a dissolution method for lumefantrine and artemether in immediate release fixed dose artemether/lumefantrine tablets

Background

Dissolution of artemether (ART) and lumefantrine (LUM) active pharmaceutical ingredients (APIs) in fixed dose combination (FDC) ART/LUM tablets is one of the critical quality attributes. Thus, the verification of the release profile of ART and LUM from FDC ART/LUM tablets using a robust and discriminatory dissolution method is crucial. Therefore, the aim of this study was to develop and validate an appropriate dissolution method for quality control of FDC ART/LUM tablets.

Methods

The dissolution medium was selected based on saturation solubility data and sink conditions. The effect of agitation speed, pH and surfactant concentration on the release of ART and LUM was evaluated by employing a two-level factorial experiment. The resulting final method was validated for linearity, precision, robustness and API stability. In addition, the discriminatory power of the method was evaluated using expired and unexpired FDC ART/LUM products.

Results

A suitable dissolution profile of FDC ART/LUM tablets was obtained in 900 ml HCl (0.025 N, pH 1.6) with 1%Myrj 52 using paddle method at 100 rpm and 37 °C. ART and LUM were analysed using a HPLC method with UV detection at wavelengths of 210 and 335 nm, respectively. The results from the stability study showed that ART and LUM were sufficiently stable in HCl (0.025 N, pH 1.6) with 1%Myrj 52 at 37 °C. The method was linear (r² = 0.999) over the concentration range of 6.25–100 μg/ml. The results for precision were within the acceptance limit (%RSD < 2). The percent relative standard deviation (< 2%) and statistically non-significant (p > 0.05) difference in release of ART and LUM observed between deliberately changed dissolution method settings (pH = 1.6 ± 0.2 or agitation speed = 100 ± 2) and optimized dissolution conditions revealed the robustness of the dissolution method. The method was capable to discriminate among different FDC ART/LUM products with different quality.

Conclusions

The developed dissolution method is robust and discriminatory. It can be used in the quality evaluation of FDC ART/LUM tablets.

First principle study of silver nanoparticle interactions with antimalarial drugs extracted from Artemisia annua plant

Silver nanoparticles have a great potential in a broad range of applications such as drug-delivery carriers because of their antiviral and antibacterial properties. In this study, the coating properties of silver nanoparticle (size range of 1.6 nm) with three common anti-malarial drugs, Artemisinin, Artemether, and Artesunate have been studied by using the quantum mechanical and classical atomistic molecular dynamics simulation in order to use as the drug delivery to treat malaria and COVID-19 diseases. The optimized structure, frequencies, charge distribution, and the electrostatic potential maps of the three drug molecules were simulated by using the density functional theory (DFT) at the B3LYP/6-311++g(d,p) level of theory. Then, molecular dynamics simulation was used to study the coating of AgNP with each of these drugs. The affinity of interaction was obtained as Artesunate > Artemether > Artemisinin which is in agreement with the DFT results on the adsorption of drugs on the Ag(111) slab.

Efficacy and safety of artemether emulsion for the treatment of mild-to-moderate acne vulgaris: a randomized pilot study

OBJECTIVE

To evaluate the efficacy and safety of artemether emulsion treating patients with mild-to-moderate acne vulgaris.

METHODS

A total of 73 (randomized 1:1) patients were externally administered either artemether emulsion (1%) or fusidic acid emulsion (5g: 0.1g) twice daily for 12 weeks. Efficacy and safety evaluations were performed at weeks 0 and 12 by Global acne Grading System (GAGS), the number of acne and papule, as well as the rate of clinical respond.

RESULTS

After 12 weeks, patients randomized to the artemether emulsion group received artemether emulsion had significantly lower GAGS scores (5.08 ± 1.99 versus 13.75 ± 4.87, p < .001) compared to patients who received fusidic acid emulsion. Patients in the artemether emulsion group had comparable baseline acne scores (11.11 ± 3.73 versus 10.75 ± 4.66, p = .626) and papule score (16.11 ± 5.58 versus 17.03 ± 6.34, p = .356), but significantly lower acne score (3.00 ± 1.55 versus 9.08 ± 4.90, p < .001) and comparable papule score (2.81 ± 1.61 versus 12.69 ± 5.45, p < .001) compared to the fusidic acid emulsion group at 12 weeks. No major adverse events were noted in either treatment group through 12 weeks.

CONCLUSIONS

Artemether emulsion had better effect in improving mild-to-moderate AV compared to fusidic acid emulsion with barely AEs.

Quality of fixed dose artemether/lumefantrine products in Jimma Zone, Ethiopia

Background

Malaria caused by Plasmodium vivax and Plasmodium falciparum is among the major public health problems in most endemic areas of the world. Artemisinin-based combination therapy (ACT) has been recommended as a first-line treatment for uncomplicated Plasmodium falciparum malaria almost in all endemic regions. Since ineffectively regulated medicines in resource limited settings could favour infiltration of poor quality anti-malarial medicines into pharmaceutical supply chain and jeopardize a positive treatment outcome, regular monitoring of the quality of anti-malarial medicines is critical. Thus, the aim of this study was to assess the quality of fixed dose combination (FDC) artemether (ART)/lumefantrine (LUM) tablets available in Jimma zone, Ethiopia.

Methods

This study was conducted in Jimma zone, Ethiopia. A total of 74 samples of FDC ART/LUM (20 mg ART/120 mg LUM) tablets were collected from 27 public facilities. All samples were subjected to visual inspection and the relevant information was recorded. The samples were transported to Jimma University Laboratory of Drug Quality (JuLaDQ) and stored at ambient temperature (20 °C to 25 °C) until analysis. The Pharmacopoeial conform/non-conform methods and the risk-based Derringer’s desirability function approach were employed to assess the pharmaceutical quality of the investigated products.

Results

The visual inspection results revealed that there were no signs of falsified in the investigated products. Identification test results of samples indicated that all samples contained the stated active pharmaceutical ingredients (APIs). The results of uniformity of mass indicated that all samples complied with International Pharmacopoeial specification limits. The assay results, expressed as percent label claim (%lc) of ART (89.8 to 108.8%, mean ± SD = 99.1 ± 3.9%) and LUM (90.0 to 111.9%, mean ± SD = 98.2 ± 3.8%) revealed that, all samples complied with International Pharmacopoeia acceptance specification limits (i.e. 90–110%lc), except one generic product (IPCA Laboratories Ltd., India) which contains excessive LUM (111.9 ± 1.7%lc). The risk priority number (RPN) results revealed that assay (RPN = 392) is relatively the most critical quality attribute followed by identity (RPN = 280) and mass uniformity (40). Quality evaluation based on psycho-physical Harrington’s scale revealed that more than 96% of samples were within the acceptable ranges (D ≥ 0.7–1.0).

Conclusions

Both Pharmacopoeial and risk-based desirability function approaches to quality evaluation applied to the investigated products revealed that above 96% FDC ART/LUM tablets circulating in public settings of Jimma zone are of good quality.

Electronic supplementary material

The online version of this article (10.1186/s12936-019-2872-1) contains supplementary material, which is available to authorized users.

Artemether improves type 1 diabetic kidney disease by regulating mitochondrial function

Many patients with type 1 diabetes mellitus suffer from progressive diabetic kidney disease (DKD). The progression of DKD is largely attributed to mitochondrial dysfunction, with key contributions from mitochondrial reactive oxygen species. Recent studies have revealed that the antimalarial drug artemether has antidiabetic effects. To identify potential effects on type 1 DKD in the present study, mice with streptozotocin-induced diabetes were treated with artemether. Treatment reduced urinary excretion of albumin and tubular injury biomarkers, increased serum albumin and total protein levels, and attenuated renal hypertrophy. In addition, artemether treatment prevented hyperglycemia, raised serum insulin levels, and restored glucagon/insulin and somatostatin/insulin ratios in islets. We found that artemether improved mitochondrial function and regulated redox balance in kidney. These results demonstrate that artemether provides renal protection in type 1 diabetes mellitus, which may be due to improved mitochondrial function.

Effect of omega-3 fatty acids administered as monotherapy or combined with artemether on experimental Schistosoma mansoni infection

Schistosomiasis is on the top list of endemic diseases in sub-Saharan Africa. Praziquantel is the drug of choice for treatment of human schistosomiasis. Yet, the sole dependence on the drug raises concerns about the potential for increased drug resistance, which would subsequently result in searching for alternative preventive chemotherapy options, ideally among natural compounds. Therefore, we conducted this work to assess the effect of omega-3 polyunsaturated fatty acids [(ω-3) PUFAs] monotherapy or combined therapy with artemether (ART) against Schistosoma mansoni infection in a mouse model. A total of 42 mice were divided into 4 groups and infected with 50 ± 5 S. mansoni cercariae for 10 weeks. Mice were treated orally with either (ω-3) PUFAs as 273 mg/ kg, 4 times/ week throughout the experiment, ART as a single dose of 400 mg/ kg, 3 weeks post-infection, or combined ART + (ω-3) PUFAs using the same respective treatment regimen, while infected untreated mice were served as controls. The study explored that combined administration of (ω-3) PUFAs and ART has the best schistosomicidal efficacy as it significantly reduced liver and spleen indices, worm count, egg burdens, and granulomas count as well as diameter. Besides, the combined regimen was associated with a significant decrease in both hepatic nitric oxide and serum interleukin-4 level. The results highlighted the possibility of using (ω-3) PUFA combined with ART as a novel anti-schistosomal combination therapy. However, further researches should be conducted to clarify the possible synergistic mechanism/s between the two natural compounds.

Artemether ameliorates type 2 diabetic kidney disease by increasing mitochondrial pyruvate carrier content in db/db mice

Diabetic kidney disease (DKD), the leading cause of kidney failure, is characterized by albuminuria and renal hypertrophy. Metabolic alterations and mitochondrial dysfunction play critical roles in DKD initiation and progression. Artemether, a methyl ether derivative of artemisinin used for the treatment of malaria, has been identified as a putative candidate for treating diabetes, but its effect on DKD has not been studied. The goal of this study was to examine the effect of artemether on type 2 diabetic db/db mice. Our results show that artemether reduced urinary albumin excretion, prevented diabetic kidney hypertrophy, attenuated glomerular basement membrane and tubular basement membrane thickening, and ameliorated foot process effacement in type 2 diabetic db/db mice. Artemether also protected against hyperglycemia and improved diabetic symptoms. In addition, it increased serum insulin level and restored the normal ratio of insulin, glucagon, and somatostatin levels in islets. Specifically, artemether increased the respiratory exchange ratio and regulated mitochondrial function and the redox state in the kidney. In conclusion, this experiment confirmed the renal protection ability of artemether in DKD. The mechanisms of this effect might be associated with the ability of artemether to increase mitochondrial pyruvate carrier content.

Susceptibility of Plasmodium falciparum to artemisinins and Plasmodium vivax to chloroquine in Phuoc Chien Commune, Ninh Thuan Province, south-central Vietnam

BACKGROUND

Reduced artemisinin susceptibility and artemisinin-based combination therapy (ACT)-resistance against Plasmodium falciparum and chloroquine (CQ)-resistant P. vivax malaria has been reported in Vietnam. Two therapeutic efficacy studies were conducted in Thuan Bac District (Ninh Thuan Province, Vietnam) in 2015 and 2016 to determine the extent of reduced artemisinin susceptibility and ACT resistant falciparum malaria, and CQ-resistant vivax malaria were present.

METHODS

Twenty-seven patients with falciparum malaria were randomized to receive artesunate alone (AS ~ 4 mg/kg/day) for 4 days followed by dihydroartemisinin (DHA) (2.2 mg/kg)-piperaquine (PPQ) (18 mg/kg) daily for 3 days or artemether (AM) (1.7 mg/kg)-lumefantrine (LUM) (12 mg/kg) twice daily for 3 days. Sixteen subjects with vivax malaria received CQ (total 25 mg/kg over 3 days). The therapeutic efficacy study for treating falciparum malaria was complemented with molecular analysis for artemisinin and piperaquine resistance, and in vitro drug susceptibility testing. Patient's drug exposure following both falciparum and vivax treatment studies was determined.

RESULTS

Twenty-five of 27 patients treated with the artemisinin regimens completed the 42-day follow-up period. None had parasites present on day 3 after commencing treatment with no incidence of recrudescence (100% curative rate). One patient on AS + DHA-PPQ was lost to follow-up and one patient had Plasmodium falciparum and Plasmodium vivax infection on day 0 by PCR. Of the vivax patients, 15 of 16 completed CQ treatment and two had a recurrence of vivax malaria on day 28, a failure rate of 13.3% (2/15). No mutations in the Pfkelch-13 gene for artemisinin resistance or exo-E415G gene polymorphism and amplification in plasmepsins 2 and 3 for piperaquine resistance were observed. In vitro testing of patient's falciparum parasites indicated susceptibility (low IC₅₀ nM values) to dihydroartemisinin, lumefantrine, piperaquine and pyronaridine. Patient's drug exposure to artesunate and lumefantrine was comparable to published data, however, blood CQ concentrations were lower.

CONCLUSIONS

Clinical findings, molecular analysis and in vitro testing revealed that the falciparum parasites at Phuoc Chien Commune were artemisinin susceptible. The clinical failure rate of the 15 vivax patients who completed CQ treatment was 13%. Further studies are required to determine whether CQ-resistant vivax malaria is present at the commune.

Quantitative determination of the antimalarials artemether and lumefantrine in biological samples: A review

Malaria is a worldwide health issue, with 216 million cases reported in 2016. Due to the widespread resistance of Plasmodium falciparum to conventional drugs, the first line treatment recommended by World Health Organization for uncomplicated malaria is artemisinin-based combined therapy (ACT), which combines two drugs with different mechanisms of action. The association of artemether and lumefantrine is the most common ACT used in the clinical practice. However, there have been reports of clinical artemisinin and derivatives partial resistance, which is defined as delayed parasite clearance. In this context, the monitoring of drug concentration in biological matrices is essential to evaluate treatment response, the need of dose adjustment and the occurrence of dose dependent adverse effects. Furthermore, it is also important for pharmacokinetic studies and in the development of generic and similar drugs. Determination of antimalarial drugs in biological matrices requires a sample pre-treatment, which involves drug extraction from the matrix and analyte concentration. The most used techniques are protein precipitation (PP), liquid-liquid extraction (LLE) and solid phase extraction (SPE). Subsequently, a liquid chromatography step is usually applied to separate interferences that could be extracted along with the analyte. Finally, the analytes are detected employing techniques that must be selective and sensitive, since the analyte might be present in trace levels. The most used approach for detection is tandem mass spectrometry (MS-MS), but ultraviolet (UV) is also employed in several studies. In this article, a review of the scientific peer-review literature dealing with validated quantitative analysis of artemether and/or lumefantrine in biological matrices, from 2000 to 2018, is presented.

A randomized trial of dihydroartemisinin-piperaquine versus artemether-lumefantrine for treatment of uncomplicated Plasmodium falciparum malaria in Mali

Background

Artemether–lumefantrine (AL) and artesunate–amodiaquine are first-line treatment for uncomplicated malaria in many endemic countries, including Mali. Dihydroartemisinin–piperaquine (DHA–PQ) is also an alternative first-line artemisinin-based combination therapy, but only few data are available on DHA–PQ efficacy in sub-Saharan Africa. The main aim of this study was to compare clinical efficacy of DHA–PQ versus AL, using the World Health Organization (WHO) 42-day in vivo protocol.

Methods

The efficacy of three-dose regimens of DHA–PQ was compared to AL combination in a randomized, comparative open label trial using the WHO 42-day follow-up protocol from 2013 to 2015 in Doneguebougou and Torodo, Mali. The primary endpoint was to access the PCR-corrected Adequate Clinical and Parasitological Responses at day 28.

Results

A total of 317 uncomplicated malaria patients were enrolled, with 159 in DHA–PQ arm and 158 in AL arm. The parasite positivity rate decreased from 68.4% (95% CI 60.5–75.5) on day 1 to 3.8% (95% CI 1.4–8.1) on day 2 for DHA–PQ and 79.8% (95% CI 72.3–85.7) on day 1 to 9.5% (95% CI 5.4–15.2) on day 2 for AL, (p = 0.04). There was a significant difference in the uncorrected ACPR between DHA–PQ and AL, both at 28-day and 42-day follow-up with 97.4% (95% CI 93.5–99.3) in DHA–PQ vs 84.5% (95% CI 77.8–89.8) in AL (p < 0.001) and 94.2% (95% CI 89.3–97.3) in DHA–PQ vs 73.4% (95% CI 65.7–80.2) in AL, respectively (p < 0.001). After molecular correction, there was no significant difference in ACPRc between DHA–PQ and AL, both at the 28-day and 42-day follow-up with 99.4% (95% CI 96.5–100) in DHA–PQ versus 98.1% (95% CI 94.5–99.6) in AL (p = 0.3) and 99.3% (95% CI 96.5–100) in DHA–PQ vs 97.4% (95% CI 93.5–99.3) in AL (p = 0.2). There was no significant difference between DHA–PQ and AL in QTc prolongation 12.1% vs 7%, respectively (p = 0.4).

Conclusion

The results showed that dihydroartemisinin–piperaquine and artemether–lumefantrine were clinically efficacious on Plasmodium falciparum parasites in Mali.

Comparison of in vitro/in vivo blood distribution and pharmacokinetics of artemisinin, artemether and dihydroartemisinin in rats

Artemisinin and its derivatives have been widely used for treatment of malaria and the therapeutic targets are considered within the red blood cells. In the recent studies on the erythrocytes' uptake of artemisinin-derivatives in vitro, applying the radioisotope-labeled technology, it was trying to predict the in vivo disposition properties, but different distribution results were revealed from a preliminary study in one human. The pharmacokinetic differences among blood cells and plasma still remain unclear. To explore the therapeutic related pharmacokinetics and compare the in vitro-in vivo blood distribution in rats, an improving blood sample preparation and LC-MS/MS detection method was developed and successfully validated. The lower limit of quantification was smaller than the previous studies. In the in vitro blood distribution studies, the content ratios from blood cells to plasma were compared in the concentrations from 20 ng/mL to 1000 ng/mL. Such ratios were determined to be 1.1-1.6 for artemisinin, 0.9-1.2 for artemether, and around 0.7 for dihydroartemisinin. In the oral administration pharmacokinetic studies in rats, the concentration ratios from blood cells to plasma were from high (2.6-3.6) to medium (1.3-2.5), and low (0.5-1.5) for artemisinin, artemether, and dihydroartemisinin respectively in all measuring time points, displaying the similar affinity order toward blood cells in artemisinin > artemether > dihydroartemisinin as the in vitro measurements. The dosages of 10 mg/kg for intravenous administrations of artemisinin and 200 mg/kg for oral administrations of artemisinin or artemether were used for the pharmacokinetic study in rats. The geometric mean exposures (AUC_(0-t)) of artemisinin, artemether and dihydroartemisinin in blood cells were determined to be 2.6 folds, 1.7 folds, or 1.2 folds greater than those in plasma, respectively. Referring to the in vitro distribution, the AUC_(0-t) ratios from the blood cells measurements to the plasma measurements of these three antimalarial drugs were also in a similar trend as the in vitro distribution measurements. Furthermore, the half-life (t_1/2) of artemether in blood cells was even longer than that in plasma, while the clearance of artemisinin, artemether, or dihydroartemisinin in blood cells was slower than that in plasma. Particularly, it was found that the concentrations of artemisinin and artemether were presented in blood cells over longer time period than in plasma above their antimalarial IC₅₀, which might result from both the affinity toward blood cells and the drugs clearance differences between blood cells and plasma. These results were indicated that the exposures and pharmacokinetic properties in the whole blood or the blood cells should be taken into account for the drug candidates with higher distribution affinity toward blood cells especially for the antimalarial drugs.

Optimization and evaluation of lipid emulsions for intravenous co-delivery of artemether and lumefantrine in severe malaria treatment

Parenteral therapy for severe and complicated malaria is necessary, but currently available parenteral antimalarials have their own drawbacks. As for recommended artemisinin-based combination therapy, antimalarial artemether and lumefantrine are limited in parenteral delivery due to their poor water solubility. Herein, the aim of this study was to develop the lipid-based emulsions for intravenous co-delivery of artemether and lumefantrine. The lipid emulsion was prepared by high-speed shear and high-pressure homogenization, and the formulations were optimized mainly by monitoring particle size distribution under autoclaved conditions. The final optimal formulation was with uniform particle size distribution (~ 220 nm), high encapsulation efficiency (~ 99%), good physiochemical stability, and acceptable hemolysis potential. The pharmacokinetic study in rats showed that C_max of artemether and lumefantrine for the optimized lipid emulsions were significantly increased than the injectable solution, which was critical for rapid antimalarial activity. Furthermore, the AUC_0-t of artemether and lumefantrine in the lipid emulsion group were 5.01- and 1.39-fold of those from the solution, respectively, suggesting enhanced bioavailability. With these findings, the developed lipid emulsion is a promising alternative parenteral therapy for the malaria treatment, especially for severe or complicated malaria.

The use and preference of artemether as a first-choice treatment for malaria: results from a cross-sectional survey in the Bata district, Equatorial Guinea

BACKGROUND

Malaria is endemic in Equatorial Guinea with stable transmission, and it remains a major cause of morbidity and mortality in children under 5 years of age. Adherence to artemisinin-based combination therapy (ACT) as a first-line treatment for uncomplicated malaria is critical to malaria control. Six years after the introduction of artesunate-amodiaquine (AS/AQ) therapy in Equatorial Guinea, adherence to the first-line treatment seems to be low in the Bata district. The factors associated with the choice of malaria treatment have not been studied previously in this area; therefore, this study aimed to analyse the preference and use of artemether as malaria treatment and its related factors in the Bata district of Equatorial Guinea.

METHODS

In 2013, a cross-sectional study was conducted in the Bata district, which involved 428 households. Bivariate and multivariate statistical analyses were conducted to determine the relevance of socio-economic, geographical, and behavioural factors that played a role in the preference and use of artemether as malaria treatment.

RESULTS

Artemether was considered the best treatment for malaria by 110 caregivers (26%), and was the antimalarial most administrated in the Bata district. It was prescribed to 117 children (27.34%); while, only 6.78% were administered AS/AQ. Caregivers living ≤ 3 km from the nearest health facility were almost two times more likely to consider artemether as the best treatment than those living farther away (95% CI 0.31-0.86). Caregivers with at least a secondary school education were 2.7 times more likely to consider artemether as the best treatment than those less educated. Children whose caregivers considered artemether the best treatment against malaria were five times more likely to be treated with artemether than children with caregivers who did not consider it the best (OR 5.07, 95% CI 2.93-8.78). In contrast, children that reported weakness as a symptom were less likely to be treated with artemether than those with other symptoms (OR 0.47, 95% CI 0.28-0.78).

CONCLUSION

Caregivers, public and private health staff, and drug sellers need to understand the importance of using ACT to treat uncomplicated malaria and the dangers of using artemisinin monotherapy.

Efficacy and safety of artemisinin-based combination therapy and chloroquine with concomitant primaquine to treat Plasmodium vivax malaria in Brazil: an open label randomized clinical trial

Background

There is general international agreement that the importance of vivax malaria has been neglected, and there is a need for new treatment approaches in an effort to progress towards control and elimination in Latin America. This open label randomized clinical trial evaluated the efficacy and safety of three treatment regimens using either one of two fixed dose artemisinin-based combinations or chloroquine in combination with a short course of primaquine (7–9 days: total dose 3–4.2 mg/kg) in Brazil. The primary objective was establishing whether cure rates above 90% could be achieved in each arm.

Results

A total of 264 patients were followed up to day 63. The cure rate of all three treatment arms was greater than 90% at 28 and 42 days. Cure rates were below 90% in all three treatment groups at day 63, although the 95% confidence interval included 90% for all three treatments. Most of the adverse events were mild in all treatment arms. Only one of the three serious adverse events was related to the treatment and significant drops in haemoglobin were rare.

Conclusion

This study demonstrated the efficacy and safety of all three regimens that were tested with 42-day cure rates that meet World Health Organization criteria. The efficacy and safety of artemisinin-based combination therapy regimens in this population offers the opportunity to treat all species of malaria with the same regimen, simplifying protocols for malaria control programmes and potentially contributing to elimination of both vivax and falciparum malaria.

Trial registration RBR-79s56s

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2192-x) contains supplementary material, which is available to authorized users.

Reduced cardiotoxicity and increased oral efficacy of artemether polymeric nanocapsules in Plasmodium berghei-infected mice

Artemether (ATM) cardiotoxicity, its short half-life and low oral bioavailability are the major limiting factors for its use to treat malaria. The purposes of this work were to study free-ATM and ATM-loaded poly-ε-caprolactone nanocapules (ATM-NC) cardiotoxicity and oral efficacy on Plasmodium berghei-infected mice. ATM-NC was obtained by interfacial polymer deposition and ATM was associated with polymeric NC oily core. For cardiotoxicity evaluation, male black C57BL6 uninfected or P. berghei-infected mice received, by oral route twice daily/4 days, vehicle (sorbitol/carboxymethylcellulose), blank-NC, free-ATM or ATM-NC at doses 40, 80 or 120 mg kg-1. Electrocardiogram (ECG) lead II signal was obtained before and after treatment. For ATM efficacy evaluation, female P. berghei-infected mice were treated the same way. ATM-NC improved antimalarial in vivo efficacy and reduced mice mortality. Free-ATM induced significantly QT and QTc intervals prolongation. ATM-NC (120 mg kg-1) given to uninfected mice reduced QT and QTc intervals prolongation 34 and 30%, respectively, compared with free-ATM. ATM-NC given to infected mice also reduced QT and QTc intervals prolongation, 28 and 27%, respectively. For the first time, the study showed a nanocarrier reducing cardiotoxicity of ATM given by oral route and it was more effective against P. berghei than free-ATM as monotherapy.

Comparison Of Efficacy Of Chloroquine And Artemether/Lumafantrine In Treating Vivax Malaria In Thall And Surrounding Area

BACKGROUND

Fever is the main complaint in patients reporting to our hospital and the most common cause of fever in our set up is malaria. The aim of this study was to know about the clinical response, efficacy and resistance of vivax malaria to chloroquine in patients reporting to Thall Scouts Hospital.

METHODS

All the adult male patients reporting to Thall Scouts Hospital with fever and other symptoms of malaria having slide positive vivax malaria were included in the study. Both thick and thin slide were used for the diagnosis and species determination of malaria. Age group of the patients was from 18-40 years old. The study was conducted for the period of two years.

RESULTS

Total number of patients included in the study was 518. Of the 518 patients, 374 (72.2%) responded to chloroquine and the remaining 144 (27.8%) were given Arthemether/Lumafantrine combination. Having positive symptoms of malaria total 374 patients treated with chloroquine 171 (45.72%) were asymptomatic after 24 hours, 98 (26.2%) after 48 hours, 78 (20.86%), after 72 hours of treatment while 27 (7.22%) were found to be resistant to chloroquine. Of the 144 patients having positive malaria treated with Artemether/Lumafantrine 62 (43.06%) were asymptomatic after 24 hours, 65 (45.14%) after 48 hours, 13 (9.03%) after 72 hours while 4 (2.78%) had still positive symptoms of malaria.

CONCLUSIONS

Vivax malaria in our set up is sensitive to both Chloroquine and Arthemether/Lumafantrine. As Chloroquine is a cheap and easily available drug, so it can be safely given to patients with vivax malaria. It will also decrease the total cost of the disease.

Reduced ex vivo susceptibility of Plasmodium falciparum after oral artemether-lumefantrine treatment in Mali

BACKGROUND

Artemisinin-based combination therapy is the recommended first-line treatment for uncomplicated falciparum malaria worldwide. However, recent studies conducted in Mali showed an increased frequency of recurrent parasitaemia following artemether-lumefantrine (AL) treatment.

METHODS

Study samples were collected during a large WANECAM study. Ex-vivo Plasmodium falciparum sensitivity to artemether and lumefantrine was assessed using the tritiated hypoxanthine-based assay. The prevalence of molecular markers of anti-malarial drug resistance (pfcrt K76T, pfmdr1 N86Y and K13-propeller) were measured by PCR and/or sequencing.

RESULTS

Overall 61 samples were successfully analysed in ex vivo studies. Mean IC50s increased significantly between baseline and recurrent parasites for both artemether (1.6 nM vs 3.2 nM, p < 0.001) and lumefantrine (1.4 nM vs 3.4 nM, p = 0.004). Wild type Pfmdr1 N86 allele was selected after treatment (71 vs 91%, 112 of 158 vs 95 of 105, p < 0.001) but not the wild type pfcrt K76 variant (23.5 vs 24.8%, 40 of 170 vs 26 of 105, p = 0.9). Three non-synonymous K13-propeller SNPs (A522C, A578S, and G638R) were found with allele frequencies <2%.

CONCLUSION

Malian post-AL P. falciparum isolates were less susceptible to artemether and lumefantrine than baseline isolates.

Schistosoma hemozoin and its possible roles

More than 95years ago Schistosoma pigment had been deemed as a degradation product of haemoglobin. Until the 1950s, scientists initiated to pay attention to understand the hematophagous habit of schistosomes, and to study the degradation of haemoglobin as well as the formation of hemozoin inside the gut of the worms. For a long time, the formation of hemozoin in both Plasmodium and in Schistosoma was considered to be the major route of heme detoxification, and hemozoin served a role in waste disposal. At the beginning of this century, the chemical structure of Schistosoma pigment was confirmed to be identical to that of malarial pigment (hemozoin) and its synthetic analogue, β-hematin. Since then, studies on Schistosoma hemozoin have been investigated by some workers and the results showed that Schistosoma hemozoin may play important roles in pathogenicity, immune modulation, iron supply for egg formation, and interaction with some anti-schistosomal drugs. In this review, we briefly review and discuss the hematophagous habit of schistosomes, degradation of haemoglobin, formation of hemozoin in the worm gut, and possible roles of hemozoin.

Improvement of solubility, dissolution and stability profile of artemether solid dispersions and self emulsified solid dispersions by solvent evaporation method

The purpose of this study was to investigate changes in the water solubility of artemether; a poorly soluble drug used for the treatment of malaria. Different solid dispersions (SDs) of artemether were prepared using artemether and polyethylene glycol 6000 at ratio 12:88 (Group 1), self-emulsified solid dispersions (SESDs) containing artemether, polyethylene glycol 6000, cremophor-A-25, olive oil, hydroxypropylmethylcellulose and transcutol in the ratio 12:75:5:4:2:2, respectively (Group 2). SESDs were also prepared by substituting cremophor-A-25 in Group 2 with poloxamer 188 (noted as Group 3). Each of these preparations was formulated using physical mixing and the solvent evaporation method. Aqueous solubility of artemether improved 11-, 95- and 102-fold, while dissolution (in simulated gastric fluid) increased 3-, 13- and 14-fold, for formulation groups 1, 2 and 3, respectively. X-ray diffraction patterns of SDs indicated a decrease in peak intensities at 10° implying reduced artemether crystallinity. Scanning electron micrographs invariably revealed embedment of artemether by various excipients and a glassy appearance for solvent evaporated mixtures for all three formulation Groups. Our findings indicate improved hydrophilic interactions for drug particles yield greater solubility and dissolution in the following order for artemether formulating methods: solvent evaporation mixtures > physical mixtures > pure artemether.

Determination of the structures of radicals formed in the reaction of antimalarial drug artemisinin with ferrous ions

While artemisinin 1 has been widely used to treat malaria in traditional Chinese medicine, its exact antimalarial mechanism remains unclear. To elucidate the mechanisms of the antimalarial action by artemisinin, the reactions of artemisinin, artemether 2 and artesunate 3 with Fe²⁺ were analyzed using an electron spin resonance (ESR), high performance liquid chromatography-electron spin resonance (HPLC-ESR) and high performance liquid chromatography-electron spin resonance-mass spectrometer (HPLC-ESR-MS). α-(4-Pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) was used as a spin trap reagent in the reactions. Radicals were detected by ESR and structures of the radicals were determined by HPLC-ESR-MS. Based on the ions, m/z 478, m/z 418 and m/z 238 which were determined by HPLC-ESR-MS, we identified following radicals: artemisinin-derived primary and secondary radicals, 6 and 7; acetyl radical, 8; a radical formed through elimination of acetyl group from 6, 10 in the reaction of artemisinin with Fe²⁺. Radicals, 7 and 8 were also detected in the reaction of artemether and artesunate.

Nanostructured lipid carriers of artemether-lumefantrine combination for intravenous therapy of cerebral malaria

Patients with cerebral malaria (CM) are unable to take oral medication due to impaired consciousness and vomiting thus necessitating parenteral therapy. Quinine, artemether, and artesunate which are currently used for parenteral malaria therapy have their own drawbacks. The World Health Organization (WHO) has now banned monotherapy and recommends artemisinin-based combination therapy for malaria treatment. However, presently there is no intravenous formulation available for combination therapy of malaria. Artemether-Lumefantrine (ARM-LFN) is a WHO approved combination for oral malaria therapy. However, the low aqueous solubility of ARM and LFN hinders their intravenous delivery. The objective of this study was to formulate ARM-LFN nanostructured lipid carriers (NLC) for intravenous therapy of CM. ARM-LFN NLC were prepared by microemulsion template technique and characterized for size, drug content, entrapment efficiency, drug release, crystallinity, morphology, amenability to autoclaving, compatibility with infusion fluids, stability, antimalarial efficacy in mice, and toxicity in rats. The ARM-LFN NLC showed sustained drug release, amenability to autoclaving, compatibility with infusion fluids, good stability, complete parasite clearance and reversal of CM symptoms with 100% survival in Plasmodium berghei-infected mice, and safety in rats. The biocompatible ARM-LFN NLC fabricated by an industrially feasible technique offer a promising solution for intravenous therapy of CM.

Prophylactic effect of artemether on human schistosomiasis mansoni among Egyptian children: A randomized controlled trial

A double-blind, randomized controlled trial was conducted in an endemic focus for Schistosoma mansoni in Kafr El-Sheikh Governorate, Northern Nile Delta, Egypt, to evaluate the prophylactic effect of artemether (ART) given in conjunction with praziquantel (PZQ). The study encompassed 913 primary school children randomly assigned to two treatment groups PZQ/ART and PZQ/ART-placebo. At baseline, both groups received 40 mg/kg body weight of PZQ twice four weeks apart, after which one group received 6 mg/kg body weight of ART every 3 weeks in 5 cycles during the transmission season and the other group received ART-placebo. At the end of the study, prevalence of infection among the PZQ/ART was approximately half that of the PZQ/ART-placebo group, i.e. 6.7% versus 11.6%, and incidence of new infections for the PZQ/ART was 2.7% versus 6.5% for the PZQ/ART-placebo. In conclusion, PZQ/ART combined therapy might be considered as an adjunct measure against human schistosomiasis, by specifically reducing transmission and therefore contribute to disease elimination.

Artemisinin anti-malarial drugs in China

Discovered by Youyou Tu, one of the 2015 Nobel Prize winners in Physiology or Medicine, together with many other Chinese scientists, artemisinin, artemether and artesunate, as well as other artemisinins, have brought the global anti-malarial treatment to a new era, saving millions of lives all around the world for the past 40 years. The discoveries of artemisinins were carried out beginning from the 1970s, a special period in China, by hundreds of scientists all together under the "whole nation" system. This article focusing on medicinal chemistry research, briefly introduced the discovery and invention course of the scientists according to the published papers, and highlighted their academic contribution and achievements.

Development of hot melt co-formulated antimalarial solid dispersion system in fixed dose form (ARLUMELT): Evaluating amorphous state and in vivo performance

The aim of this study was to investigate the industrial feasibility of developing a co-formulated solid dispersion (SD) containing two antimalarial drugs artemether (ARTM) and lumefantrine (LUMF). Soluplus(®) (polyethyleneglycol-polyvinyl caprolactam-polyvinyl acetate grafted copolymer) was used as primary carrier matrices via hot-melt extrusion processing to improve solubility profile and the oral bioavailability of the combination. Based on the preliminary screening, the optimized quantities of PEG 400, Lutrol F127 and Lutrol F68 were incorporated as surfactant with soluplus in different ratios to improve extrudability, increase wettability and the melt viscosity of the HME process. Soluplus(®) was proved to successfully stabilize both the drugs inside its polymeric network during extrusion via forming a stable solid dispersion. Physicochemical properties of the APIs and the SDs characterized by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), MDSC, FTIR spectroscopy and X-ray diffractometry (XRD) revealed the amorphous existence of the drug in all SDs developed. Molecular level morphology of solid dispersion characterized by using advanced physicochemical characterization techniques such as Raman spectroscopy, atomic force microscopy (AFM) and 2D NMR showed the transformation of the crystalline drugs to its stable amorphous state. All manufactured SDs retained their amorphicity even after a stability study conducted in accelerated condition over 6 months. The solubility and in vitro dissolution performance of both drugs in SD formulations was improved significantly when compared with pure drugs and marketed product while the in vivo studies revealed the same.The pharmacokinetic studies in rats revealed that the SD (AL1) shows a 44.12-65.24 folds increase in the AUC(0-72) and 42.87-172.61 folds increase in Cmax compared to that of pure drugs and a better bioavailability than that of commercial product.

A randomized trial of artesunate-amodiaquine versus artemether-lumefantrine for the treatment of acute uncomplicated malaria in pregnancy

OBJECTIVE

To compare the artesunate-amodiaquine and artemether-lumefantrine combinations in the treatment of acute uncomplicated falciparum malaria during pregnancy.

METHODS

Between January and July, 2013, a double-blind randomized trial was undertaken of symptomatic pregnant women (second/third trimester) with malaria parasitemia who attended a center in Ile-Ife, Nigeria. Participants were assigned to receive artesunate-amodiaquine or artemether-lumefantrine (twice daily on days 1-3) according to a computer-generated randomization sequence. Participants and investigators were masked to group allocation. Clinical evaluations and malaria parasite counts were performed at baseline and on days 2, 3, 7, and 28. Mean interval to symptomatic relief, day-3 parasite clearance, day-28 cure rate, and adverse effects were assessed.

RESULTS

Of 75 women assigned to each group, 65 in the artesunate-amodiaquine group and 71 in the artemether-lumefantrine group completed the study. No significant differences between the artesunate-amodiaquine and artemether-lumefantrine groups were recorded for mean interval to symptomatic relief (2.2 ± 1.0 days vs 2.0 ± 0.8 days; P=0.090), day-3 parasite clearance (58/65 [89.2%] vs 66/71 [93.0%]; P=0.444), and day-28 cure rate (64/65 [98.5%] vs 67/71 [94.4%]; P=0.138). Adverse effects (body weakness and pruritus) were more common among women assigned to artesunate-amodiaquine (30/75 [40.0%]) than among those assigned to artemether-lumefantrine (2/75 [2.7%]; P<0.001).

CONCLUSION

Efficacies of the regimens are similar among pregnant women. However, adverse effects are more common with artesunate-amodiaquine. Pan-African Clinical Trial Registry: PACTR201310000484185.