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Sample records for antimalarial drug quality

  1. Quality of antimalarials at the epicenter of antimalarial drug resistance: results from an overt and mystery client survey in Cambodia.

    PubMed

    Yeung, Shunmay; Lawford, Harriet L S; Tabernero, Patricia; Nguon, Chea; van Wyk, Albert; Malik, Naiela; DeSousa, Mikhael; Rada, Ouk; Boravann, Mam; Dwivedi, Prabha; Hostetler, Dana M; Swamidoss, Isabel; Green, Michael D; Fernandez, Facundo M; Kaur, Harparkash

    2015-06-01

    Widespread availability of monotherapies and falsified antimalarials is thought to have contributed to the historical development of multidrug-resistant malaria in Cambodia. This study aimed to document the quality of artemisinin-containing antimalarials (ACAs) and to compare two methods of collecting antimalarials from drug outlets: through open surveyors and mystery clients (MCs). Few oral artemisinin-based monotherapies and no suspected falsified medicines were found. All 291 samples contained the stated active pharmaceutical ingredient (API) of which 69% were considered good quality by chemical analysis. Overall, medicine quality did not differ by collection method, although open surveyors were less likely to obtain oral artemisinin-based monotherapies than MCs. The results are an encouraging indication of the positive impact of the country's efforts to tackle falsified antimalarials and artemisinin-based monotherapies. However, poor-quality medicines remain an ongoing challenge that demands sustained political will and investment of human and financial resources.

  2. Quality of Antimalarials at the Epicenter of Antimalarial Drug Resistance: Results from an Overt and Mystery Client Survey in Cambodia

    PubMed Central

    Yeung, Shunmay; Lawford, Harriet L. S.; Tabernero, Patricia; Nguon, Chea; van Wyk, Albert; Malik, Naiela; DeSousa, Mikhael; Rada, Ouk; Boravann, Mam; Dwivedi, Prabha; Hostetler, Dana M.; Swamidoss, Isabel; Green, Michael D.; Fernandez, Facundo M.; Kaur, Harparkash

    2015-01-01

    Widespread availability of monotherapies and falsified antimalarials is thought to have contributed to the historical development of multidrug-resistant malaria in Cambodia. This study aimed to document the quality of artemisinin-containing antimalarials (ACAs) and to compare two methods of collecting antimalarials from drug outlets: through open surveyors and mystery clients (MCs). Few oral artemisinin-based monotherapies and no suspected falsified medicines were found. All 291 samples contained the stated active pharmaceutical ingredient (API) of which 69% were considered good quality by chemical analysis. Overall, medicine quality did not differ by collection method, although open surveyors were less likely to obtain oral artemisinin-based monotherapies than MCs. The results are an encouraging indication of the positive impact of the country's efforts to tackle falsified antimalarials and artemisinin-based monotherapies. However, poor-quality medicines remain an ongoing challenge that demands sustained political will and investment of human and financial resources. PMID:25897063

  3. Anti-malarial drug quality in Lagos and Accra - a comparison of various quality assessments

    PubMed Central

    2010-01-01

    Background Two major cities in West Africa, Accra, the capital of Ghana, and Lagos, the largest city of Nigeria, have significant problems with substandard pharmaceuticals. Both have actively combated the problem in recent years, particularly by screening products on the market using the Global Pharma Health Fund e.V. Minilab® protocol. Random sampling of medicines from the two cities at least twice over the past 30 months allows a tentative assessment of whether improvements in drug quality have occurred. Since intelligence provided by investigators indicates that some counterfeit producers may be adapting products to pass Minilab tests, the results are compared with those from a Raman spectrometer and discrepancies are discussed. Methods Between mid-2007 and early-2010, samples of anti-malarial drugs were bought covertly from pharmacies in Lagos on three different occasions (October 2007, December 2008, February 2010), and from pharmacies in Accra on two different occasions (October 2007, February 2010). All samples were tested using the Minilab® protocol, which includes disintegration and active ingredient assays as well as visual inspection, and most samples were also tested by Raman spectrometry. Results In Lagos, the failure rate in the 2010 sampling fell to 29% of the 2007 finding using the Minilab® protocol, 53% using Raman spectrometry, and 46% using visual inspection. In Accra, the failure rate in the 2010 sampling fell to 54% of the 2007 finding using the Minilab® protocol, 72% using Raman spectrometry, and 90% using visual inspection. Conclusions The evidence presented shows that drug quality is probably improving in both cities, especially Lagos, since major reductions of failure rates over time occur with all means of assessment. Many more samples failed when examined by Raman spectrometry than by Minilab® protocol. The discrepancy is most likely caused by the two techniques measuring different aspects of the medication and hence the discrepancy

  4. Antimalarial drug resistance: An overview

    PubMed Central

    Antony, Hiasindh Ashmi; Parija, Subhash Chandra

    2016-01-01

    Malaria is a major public health burden throughout the world. Resistance to the antimalarial drugs has increased the mortality and morbidity rate that is achieved so far through the malaria control program. Monitoring the drug resistance to the available antimalarial drugs helps to implement effective drug policy, through the in vivo efficacy studies, in vitro drug susceptibility tests and detection of molecular markers. It is important to understand the mechanism of the antimalarial drugs, as it is one of the key factors in the emergence and spread of drug resistance. This review summarizes the commonly used antimalarial drugs, their mechanism of action and the genetic markers validated so far for the detection of drug-resistant parasites. PMID:26998432

  5. [Resistance to the antimalarial drugs].

    PubMed

    Venanzi, E; López-Vélez, R

    2016-09-01

    Malaria is one of the most widespread infectious diseases around the world with 214 million cases and 438,000 deaths in 2015. In the early twentieth century it was described for the first time the resistance to quinine and, since then, drug resistance to antimalarial drugs has spread up to represent a global challenge in the fight and control of malaria. Understanding the mechanisms, geography and monitoring tools that we can act against resistance to antimalarial drugs is critical to prevent its expansion. PMID:27608319

  6. Quality of anti-malarial drugs provided by public and private healthcare providers in south-east Nigeria

    PubMed Central

    Onwujekwe, Obinna; Kaur, Harparkash; Dike, Nkem; Shu, Elvis; Uzochukwu, Benjamin; Hanson, Kara; Okoye, Viola; Okonkwo, Paul

    2009-01-01

    Background There is little existing knowledge about actual quality of drugs provided by different providers in Nigeria and in many sub-Saharan African countries. Such information is important for improving malaria treatment that will help in the development and implementation of actions designed to improve the quality of treatment. The objective of the study was to determine the quality of drugs used for the treatment of malaria in a broad spectrum of public and private healthcare providers. Methods The study was undertaken in six towns (three urban and three rural) in Anambra state, south-east Nigeria. Anti-malarials (225 samples), which included artesunate, dihydroartemisinin, sulphadoxine-pyrimethamine (SP), quinine, and chloroquine, were either purchased or collected from randomly selected providers. The quality of these drugs was assessed by laboratory analysis of the dissolution profile using published pharmacopoeial monograms and measuring the amount of active ingredient using high performance liquid chromatography (HPLC). Findings It was found that 60 (37%) of the anti-malarials tested did not meet the United States Pharmacopoeia (USP) specifications for the amount of active ingredients, with the suspect drugs either lacking the active ingredients or containing suboptimal quantities of the active ingredients. Quinine (46%) and SP formulations (39%) were among drugs that did not satisfy the tolerance limits published in USP monograms. A total of 78% of the suspect drugs were from private facilities, mostly low-level providers, such as patent medicine dealers (vendors). Conclusion This study found that there was a high prevalence of poor quality drugs. The findings provide areas for public intervention to improve the quality of malaria treatment services. There should be enforced checks and regulation of drug supply management as well as stiffer penalties for people stocking substandard and counterfeit drugs. PMID:19208221

  7. Antimalarial Drug Quality in the Most Severely Malarious Parts of Africa – A Six Country Study

    PubMed Central

    Bate, Roger; Coticelli, Philip; Tren, Richard; Attaran, Amir

    2008-01-01

    A range of antimalarial drugs were procured from private pharmacies in urban and peri-urban areas in the major cities of six African countries, situated in the part of that continent and the world that is most highly endemic for malaria. Semi-quantitative thin-layer chromatography (TLC) and dissolution testing were used to measure active pharmaceutical ingredient content against internationally acceptable standards. 35% of all samples tested failed either or both tests, and were substandard. Further, 33% of treatments collected were artemisinin monotherapies, most of which (78%) were manufactured in disobservance of an appeal by the World Health Organisation (WHO) to withdraw these clinically inappropriate medicines from the market. The high persistence of substandard drugs and clinically inappropriate artemisinin monotherapies in the private sector risks patient safety and, through drug resistance, places the future of malaria treatment at risk globally. PMID:18461128

  8. Substandard Antimalarials Available in Afghanistan: A Case for Assessing the Quality of Drugs in Resource Poor Settings

    PubMed Central

    Lalani, Mirza; Kaur, Harparkash; Mohammed, Nader; Mailk, Naiela; van Wyk, Albert; Jan, Sakhi; Kakar, Rishtya Meena; Mojadidi, Mohammed Khalid; Leslie, Toby

    2015-01-01

    Good-quality antimalarials are crucial for the effective treatment and control of malaria. A total of 7,740 individual and packaged tablets, ampoules, and syrups were obtained from 60 randomly selected public (N = 35) and private outlets (N = 25) in Afghanistan. Of these, 134 samples were screened using the Global Pharma Health Fund (GPHF) MiniLab® in Kabul with 33/126 (26%) samples failing the MiniLab® disintegration test. The quality of a subsample (N = 37) of cholorquine, quinine, and sulfadoxine/pyrimethamine tablets was assessed by in vitro dissolution testing following U.S. Pharmacopeia (USP) monographs at a bioanalytical laboratory in London, United Kingdom. Overall, 12/32 (32%) samples of sulfadoxine/pyrimethamine and quinine were found not to comply with the USP tolerance limits. Substandard antimalarials were available in Afghanistan demonstrating that continuous monitoring of drug quality is warranted. However, in Afghanistan as in many low-income countries, capacity to determine and monitor drug quality using methods such as dissolution testing needs to be established to empower national authorities to take appropriate action in setting up legislation and regulation. PMID:25897070

  9. Substandard antimalarials available in Afghanistan: a case for assessing the quality of drugs in resource poor settings.

    PubMed

    Lalani, Mirza; Kaur, Harparkash; Mohammed, Nader; Mailk, Naiela; van Wyk, Albert; Jan, Sakhi; Kakar, Rishtya Meena; Mojadidi, Mohammed Khalid; Leslie, Toby

    2015-06-01

    Good-quality antimalarials are crucial for the effective treatment and control of malaria. A total of 7,740 individual and packaged tablets, ampoules, and syrups were obtained from 60 randomly selected public (N = 35) and private outlets (N = 25) in Afghanistan. Of these, 134 samples were screened using the Global Pharma Health Fund (GPHF) MiniLab® in Kabul with 33/126 (26%) samples failing the MiniLab® disintegration test. The quality of a subsample (N = 37) of cholorquine, quinine, and sulfadoxine/pyrimethamine tablets was assessed by in vitro dissolution testing following U.S. Pharmacopeia (USP) monographs at a bioanalytical laboratory in London, United Kingdom. Overall, 12/32 (32%) samples of sulfadoxine/pyrimethamine and quinine were found not to comply with the USP tolerance limits. Substandard antimalarials were available in Afghanistan demonstrating that continuous monitoring of drug quality is warranted. However, in Afghanistan as in many low-income countries, capacity to determine and monitor drug quality using methods such as dissolution testing needs to be established to empower national authorities to take appropriate action in setting up legislation and regulation.

  10. Substandard antimalarials available in Afghanistan: a case for assessing the quality of drugs in resource poor settings.

    PubMed

    Lalani, Mirza; Kaur, Harparkash; Mohammed, Nader; Mailk, Naiela; van Wyk, Albert; Jan, Sakhi; Kakar, Rishtya Meena; Mojadidi, Mohammed Khalid; Leslie, Toby

    2015-06-01

    Good-quality antimalarials are crucial for the effective treatment and control of malaria. A total of 7,740 individual and packaged tablets, ampoules, and syrups were obtained from 60 randomly selected public (N = 35) and private outlets (N = 25) in Afghanistan. Of these, 134 samples were screened using the Global Pharma Health Fund (GPHF) MiniLab® in Kabul with 33/126 (26%) samples failing the MiniLab® disintegration test. The quality of a subsample (N = 37) of cholorquine, quinine, and sulfadoxine/pyrimethamine tablets was assessed by in vitro dissolution testing following U.S. Pharmacopeia (USP) monographs at a bioanalytical laboratory in London, United Kingdom. Overall, 12/32 (32%) samples of sulfadoxine/pyrimethamine and quinine were found not to comply with the USP tolerance limits. Substandard antimalarials were available in Afghanistan demonstrating that continuous monitoring of drug quality is warranted. However, in Afghanistan as in many low-income countries, capacity to determine and monitor drug quality using methods such as dissolution testing needs to be established to empower national authorities to take appropriate action in setting up legislation and regulation. PMID:25897070

  11. World Antimalarial Resistance Network I: clinical efficacy of antimalarial drugs.

    PubMed

    Price, Ric N; Dorsey, Grant; Ashley, Elizabeth A; Barnes, Karen I; Baird, J Kevin; d'Alessandro, Umberto; Guerin, Philippe J; Laufer, Miriam K; Naidoo, Inbarani; Nosten, François; Olliaro, Piero; Plowe, Christopher V; Ringwald, Pascal; Sibley, Carol H; Stepniewska, Kasia; White, Nicholas J

    2007-01-01

    The proliferation of antimalarial drug trials in the last ten years provides the opportunity to launch a concerted global surveillance effort to monitor antimalarial drug efficacy. The diversity of clinical study designs and analytical methods undermines the current ability to achieve this. The proposed World Antimalarial Resistance Network (WARN) aims to establish a comprehensive clinical database from which standardised estimates of antimalarial efficacy can be derived and monitored over time from diverse geographical and endemic regions. The emphasis of this initiative is on five key variables which define the therapeutic response. Ensuring that these data are collected at the individual patient level in a consistent format will facilitate better data management and analytical practices, and ensure that clinical data can be readily collated and made amenable for pooled analyses. Such an approach, if widely adopted will permit accurate and timely recognition of trends in drug efficacy. This will guide not only appropriate interventions to deal with established multidrug resistant strains of malaria, but also facilitate prompt action when new strains of drug resistant plasmodia first emerge. A comprehensive global database incorporating the key determinants of the clinical response with in vitro, molecular and pharmacokinetic parameters will bring together relevant data on host, drug and parasite factors that are fundamental contributors to treatment efficacy. This resource will help guide rational drug policies that optimize antimalarial drug use, in the hope that the emergence and spread of resistance to new drugs can be, if not prevented, at least delayed.

  12. Rational quality assessment procedure for less-investigated herbal medicines: Case of a Congolese antimalarial drug with an analytical report.

    PubMed

    Tshitenge, Dieudonné Tshitenge; Ioset, Karine Ndjoko; Lami, José Nzunzu; Ndelo-di-Phanzu, Josaphat; Mufusama, Jean-Pierre Koy Sita; Bringmann, Gerhard

    2016-04-01

    Herbal medicines are the most globally used type of medical drugs. Their high cultural acceptability is due to the experienced safety and efficiency over centuries of use. Many of them are still phytochemically less-investigated, and are used without standardization or quality control. Choosing SIROP KILMA, an authorized Congolese antimalarial phytomedicine, as a model case, our study describes an interdisciplinary approach for a rational quality assessment of herbal drugs in general. It combines an authentication step of the herbal remedy prior to any fingerprinting, the isolation of the major constituents, the development and validation of an HPLC-DAD analytical method with internal markers, and the application of the method to several batches of the herbal medicine (here KILMA) thus permitting the establishment of a quantitative fingerprint. From the constitutive plants of KILMA, acteoside, isoacteoside, stachannin A, and pectolinarigenin-7-O-glucoside were isolated, and acteoside was used as the prime marker for the validation of an analytical method. This study contributes to the efforts of the WHO for the establishment of standards enabling the analytical evaluation of herbal materials. Moreover, the paper describes the first phytochemical and analytical report on a marketed Congolese phytomedicine.

  13. Antimalarial drug resistance and combination chemotherapy.

    PubMed Central

    White, N

    1999-01-01

    Antimarial drug resistance develops when spontaneously occurring parasite mutants with reduced susceptibility are selected, and are then transmitted. Drugs for which a single point mutation confers a marked reduction in susceptibility are particularly vulnerable. Low clearance and a shallow concentration-effect relationship increase the chance of selection. Use of combinations of antimalarials that do not share the same resistance mechanisms will reduce the chance of selection because the chance of a resistant mutant surviving is the product of the per parasite mutation rates for the individual drugs, multiplied by the number of parasites in an infection that are exposed to the drugs. Artemisinin derivatives are particularly effective combination partners because (i) they are very active antimalarials, producing up to 10,000-fold reductions in parasite biomass per asexual cycle; (ii) they reduce malaria transmissibility; and (iii) no resistance to these drugs has been reported yet. There are good arguments for no longer using antimalarial drugs alone in treatment, and instead always using a combination with artemisinin or one of its derivatives. PMID:10365399

  14. Pricing, distribution, and use of antimalarial drugs.

    PubMed Central

    Foster, S. D.

    1991-01-01

    Prices of new antimalarial drugs are targeted at the "travellers' market" in developed countries, which makes them unaffordable in malaria-endemic countries where the per capita annual drug expenditures are US$ 5 or less. Antimalarials are distributed through a variety of channels in both public and private sectors, the official malaria control programmes accounting for 25-30% of chloroquine distribution. The unofficial drug sellers in markets, streets, and village shops account for as much as half of antimalarials distributed in many developing countries. Use of antimalarials through the health services is often poor; drug shortages are common and overprescription and overuse of injections are significant problems. Anxiety over drug costs may prevent patients from getting the necessary treatment for malaria, especially because of the seasonal appearance of this disease when people's cash reserves are very low. The high costs may lead them to unofficial sources, which will sell a single tablet instead of a complete course of treatment, and subsequently to increased, often irrational demand for more drugs and more injections. Increasingly people are resorting to self-medication for malaria, which may cause delays in seeking proper treatment in cases of failure, especially in areas where chloroquine resistance has increased rapidly. Self-medication is now widespread, and measures to restrict the illicit sale of drugs have been unsuccessful. The "unofficial" channels thus represent an unacknowledged extension of the health services in many countries; suggestions are advanced to encourage better self-medication by increasing the knowledge base among the population at large (mothers, schoolchildren, market sellers, and shopkeepers), with an emphasis on correct dosing and on the importance of seeking further treatment without delay, if necessary. PMID:1893512

  15. Substandard anti-malarial drugs in Burkina Faso

    PubMed Central

    Tipke, Maike; Diallo, Salou; Coulibaly, Boubacar; Störzinger, Dominic; Hoppe-Tichy, Torsten; Sie, Ali; Müller, Olaf

    2008-01-01

    Background There is concern about an increasing infiltration of markets by substandard and fake medications against life-threatening diseases in developing countries. This is particularly worrying with regard to the increasing resistance development of Plasmodium falciparum against affordable anti-malarial medications, which has led to a change to more expensive drugs in most endemic countries. Methods A representative sample of modern anti-malarial medications from licensed (public and private pharmacies, community health workers) and illicit (market and street vendors, shops) sources has been collected in the Nouna Health District in north-western Burkina Faso in 2006. All drugs were tested for their quality with the standard procedures of the German Pharma Health Fund-Minilab. Detected low standard drugs were re-tested with European Pharmacopoeia 2.9.1 standards for disintegration and ultraviolet-visible spectroscopy at the laboratory of the Heidelberg University for confirmation. Results Overall, 86 anti-malarial drug samples were collected, of which 77 samples have been included in the final analysis. The sample consisted of 39/77 (50%) chloroquine, 10/77 (13%) pyrimethamine-sulphadoxine, 9/77 (12%) quinine, 6/77 (8%) amodiaquine, 9/77 (12%) artesunate, and 4/77 (5%) artemether-lumefantrine. 32/77 (42%) drug samples were found to be of poor quality, of which 28 samples failed the visual inspection, nine samples had substandard concentrations of the active ingredient, four samples showed poor disintegration, and one sample contained non of the stated active ingredient. The licensed and the illicit market contributed 5/47 (10.6%) and 27/30 (90.0%) samples of substandard drugs respectively. Conclusion These findings provide further evidence for the wide-spread existence of substandard anti-malarial medications in Africa and call for strengthening of the regulatory and quality control capacity of affected countries, particularly in view of the now wider available

  16. Expanding the Antimalarial Drug Arsenal-Now, But How?

    PubMed

    Grimberg, Brian T; Mehlotra, Rajeev K

    2011-05-01

    The number of available and effective antimalarial drugs is quickly dwindling. This is mainly because a number of drug resistance-associated mutations in malaria parasite genes, such as crt, mdr1, dhfr/dhps, and others, have led to widespread resistance to all known classes of antimalarial compounds. Unfortunately, malaria parasites have started to exhibit some level of resistance in Southeast Asia even to the most recently introduced class of drugs, artemisinins. While there is much need, the antimalarial drug development pipeline remains woefully thin, with little chemical diversity, and there is currently no alternative to the precious artemisinins. It is difficult to predict where the next generation of antimalarial drugs will come from; however, there are six major approaches: (i) re-optimizing the use of existing antimalarials by either replacement/rotation or combination approach; (ii) repurposing drugs that are currently used to treat other infections or diseases; (iii) chemically modifying existing antimalarial compounds; (iv) exploring natural sources; (v) large-scale screening of diverse chemical libraries; and (vi) through parasite genome-based ("targeted") discoveries. When any newly discovered effective antimalarial treatment is used by the populus, we must maintain constant vigilance for both parasite-specific and human-related factors that are likely to hamper its success. This article is neither comprehensive nor conclusive. Our purpose is to provide an overview of antimalarial drug resistance, associated parasite genetic factors (1. Introduction; 2. Emergence of artemisinin resistance in P. falciparum), and the antimalarial drug development pipeline (3. Overview of the global pipeline of antimalarial drugs), and highlight some examples of the aforementioned approaches to future antimalarial treatment. These approaches can be categorized into "short term" (4. Feasible options for now) and "long term" (5. Next generation of antimalarial treatment

  17. Expanding the Antimalarial Drug Arsenal—Now, But How?

    PubMed Central

    Grimberg, Brian T.; Mehlotra, Rajeev K.

    2011-01-01

    The number of available and effective antimalarial drugs is quickly dwindling. This is mainly because a number of drug resistance-associated mutations in malaria parasite genes, such as crt, mdr1, dhfr/dhps, and others, have led to widespread resistance to all known classes of antimalarial compounds. Unfortunately, malaria parasites have started to exhibit some level of resistance in Southeast Asia even to the most recently introduced class of drugs, artemisinins. While there is much need, the antimalarial drug development pipeline remains woefully thin, with little chemical diversity, and there is currently no alternative to the precious artemisinins. It is difficult to predict where the next generation of antimalarial drugs will come from; however, there are six major approaches: (i) re-optimizing the use of existing antimalarials by either replacement/rotation or combination approach; (ii) repurposing drugs that are currently used to treat other infections or diseases; (iii) chemically modifying existing antimalarial compounds; (iv) exploring natural sources; (v) large-scale screening of diverse chemical libraries; and (vi) through parasite genome-based (“targeted”) discoveries. When any newly discovered effective antimalarial treatment is used by the populus, we must maintain constant vigilance for both parasite-specific and human-related factors that are likely to hamper its success. This article is neither comprehensive nor conclusive. Our purpose is to provide an overview of antimalarial drug resistance, associated parasite genetic factors (1. Introduction; 2. Emergence of artemisinin resistance in P. falciparum), and the antimalarial drug development pipeline (3. Overview of the global pipeline of antimalarial drugs), and highlight some examples of the aforementioned approaches to future antimalarial treatment. These approaches can be categorized into “short term” (4. Feasible options for now) and “long term” (5. Next generation of antimalarial

  18. Drug Discovery and Development of Antimalarial Agents: Recent Advances.

    PubMed

    Thota, Sreekanth; Yerra, Rajeshwar

    2016-01-01

    Malaria, a deadly infectious parasitic disease, is a major issue of public health in the world today and already produces serious economic constraints in the endemic countries. Most of the malarial infections and deaths are due to Plasmodium falciparum and Plasmodium vivax species. The recent emergence of resistance necessitates the search for new antimalarial drugs, which overcome the resistance and act through new mechanisms. Although much effort has been directed towards the discovery of novel antimalarial drugs. 4-anilino quinolone triazines as potent antimalarial agents, their in silico modelling and bioevaluation as Plasmodium falciparum transketolase and β-hematin inhibitors has been reported. This review is primarily focused on the drug discovery of the recent advances in the development of antimalarial agents and their mechanism of action.

  19. Anti-malarial Drug Design by Targeting Apicoplasts: New Perspectives

    PubMed Central

    Mukherjee, Avinaba; Sadhukhan, Gobinda Chandra

    2016-01-01

    Objectives: Malaria has been a major global health problem in recent times with increasing mortality. Current treatment methods include parasiticidal drugs and vaccinations. However, resistance among malarial parasites to the existing drugs has emerged as a significant area of concern in anti-malarial drug design. Researchers are now desperately looking for new targets to develop anti-malarials drug which is more target specific. Malarial parasites harbor a plastid-like organelle known as the ‘apicoplast’, which is thought to provide an exciting new outlook for the development of drugs to be used against the parasite. This review elaborates on the current state of development of novel compounds targeted againstemerging malaria parasites. Methods: The apicoplast, originates by an endosymbiotic process, contains a range of metabolic pathways and housekeeping processes that differ from the host body and thereby presents ideal strategies for anti-malarial drug therapy. Drugs are designed by targeting the unique mechanism of the apicoplasts genetic machinery. Several anabolic and catabolic processes, like fatty acid, isopenetyl diphosphate and heme synthess in this organelle, have also been targeted by drugs. Results: Apicoplasts offer exciting opportunities for the development of malarial treatment specific drugs have been found to act by disrupting this organelle’s function, which wouldimpede the survival of the parasite. Conclusion: Recent advanced drugs, their modes of action, and their advantages in the treatment of malaria by using apicoplasts as a target are discussed in this review which thought to be very useful in desigining anti-malarial drugs. Targetting the genetic machinery of apicoplast shows a great advantange regarding anti-malarial drug design. Critical knowledge of these new drugs would give a healthier understanding for deciphering the mechanism of action of anti-malarial drugs when targeting apicoplasts to overcome drug resistance. PMID

  20. Ecotoxicological evaluation of the antimalarial drug chloroquine.

    PubMed

    Zurita, Jorge L; Jos, Angeles; del Peso, Ana; Salguero, Manuel; López-Artíguez, Miguel; Repetto, Guillermo

    2005-10-15

    There is limited information available about the potential environmental effects of chloroquine (CQ), a widely used antimalarial agent and a promising inexpensive drug in the management of HIV disease. The acute effects of CQ were studied using four ecotoxicological model systems. The most sensitive bioindicator was the immobilization of the cladoceran Daphnia magna, with an EC50 of 12 microM CQ at 72 h and a non-observed adverse effect level of 2.5 microM CQ, followed very closely by the decrease of the uptake of neutral red and the reduction of the lysosomal function in the fish cell line PLHC-1 derived from the top minnow Poeciliopsis lucida, probably due to the selective accumulation of the drug into the lysosomes. There was significant cellular stress as indicated by the increases on metallothionein and glucose-6P dehydrogenase levels after 24 h of exposure and succinate dehydrogenase activity mainly after 48 h. No changes were observed for ethoxyresorufin-O-deethylase (EROD) activity. The least sensitive model was the inhibition of bioluminescence in the bacterium Vibrio fischeri. An increase of more than five-fold in the toxicity from 24 to 72 h of exposure was observed for the inhibition of the growth in the alga Chlorella vulgaris and the content of total protein and MTS tetrazolium salt metabolization in PLHC-1 cells. At the morphological level, the most evident alterations in PLHC-1 cultures were hydropic degeneration from 25 microM CQ after 24h of exposure and the presence of many cells with pyknotic nuclei, condensed cytoplasm and apoptosis with concentrations higher than 50 microM CQ after 48 h of exposure. In conclusion, CQ should be classified as harmful to aquatic organisms. PMID:16153718

  1. Antimalarial drug policy in India: Past, present & future

    PubMed Central

    Anvikar, Anupkumar R.; Arora, Usha; Sonal, G.S.; Mishra, Neelima; Shahi, Bharatendu; Savargaonkar, Deepali; Kumar, Navin; Shah, Naman K.; Valecha, Neena

    2014-01-01

    The use of antimalarial drugs in India has evolved since the introduction of quinine in the 17th century. Since the formal establishment of a malaria control programme in 1953, shortly after independence, treatments provided by the public sector ranged from chloroquine, the mainstay drug for many decades, to the newer, recently introduced artemisinin based combination therapy. The complexity of considerations in antimalarial treatment led to the formulation of a National Antimalarial Drug Policy to guide procurement as well as communicate best practices to both public and private healthcare providers. Challenges addressed in the policy include the use of presumptive treatment, the introduction of alternate treatments for drug-resistant malaria, the duration of primaquine therapy to prevent relapses of vivax malaria, the treatment of malaria in pregnancy, and the choice of drugs for chemoprophylaxis. While data on antimalarial drug resistance and both public and private sector treatment practices have been recently reviewed, the policy process of setting national standards has not. In this perspective on antimalarial drug policy, this review highlights its relevant history, analyzes the current policy, and examines future directions. PMID:24718394

  2. Antimalarial Drug Discovery: From Quinine to the Dream of Eradication

    PubMed Central

    2013-01-01

    The search for antimalarial remedies predates modern medicine and the concept of small molecule chemotherapy, yet has played a central role in the development of both. This history is reviewed in the context of the current renaissance in antimalarial drug discovery, which is seeing modern drug discovery approaches applied to the problem for the first time. Great strides have been made in the past decade, but further innovations from the drug discovery community will be required if the ultimate dream of eradication is to be achieved. PMID:24790706

  3. Drug resistance genomics of the antimalarial drug artemisinin.

    PubMed

    Winzeler, Elizabeth A; Manary, Micah J

    2014-01-01

    Across the globe, over 200 million annual malaria infections result in up to 660,000 deaths, 77% of which occur in children under the age of five years. Although prevention is important, malaria deaths are typically prevented by using antimalarial drugs that eliminate symptoms and clear parasites from the blood. Artemisinins are one of the few remaining compound classes that can be used to cure multidrug-resistant Plasmodium falciparum infections. Unfortunately, clinical trials from Southeast Asia are showing that artemisinin-based treatments are beginning to lose their effectiveness, adding renewed urgency to the search for the genetic determinants of parasite resistance to this important drug class. We review the genetic and genomic approaches that have led to an improved understanding of artemisinin resistance, including the identification of resistance-conferring mutations in the P. falciparum kelch13 gene. PMID:25470531

  4. Miniaturized Cultivation of Microbiota for Antimalarial Drug Discovery.

    PubMed

    Waterman, Carrie; Calcul, Laurent; Beau, Jeremy; Ma, Wai Sheung; Lebar, Matthew D; von Salm, Jacqueline L; Harter, Charles; Mutka, Tina; Morton, Lindsay C; Maignan, Patrick; Barisic, Betty; van Olphen, Alberto; Kyle, Dennis E; Vrijmoed, Lilian; Pang, Ka-Lai; Pearce, Cedric J; Baker, Bill J

    2016-01-01

    The ongoing search for effective antiplasmodial agents remains essential in the fight against malaria worldwide. Emerging parasitic drug resistance places an urgent need to explore chemotherapies with novel structures and mechanisms of action. Natural products have historically provided effective antimalarial drug scaffolds. In an effort to search nature's chemical potential for antiplasmodial agents, unconventionally sourced organisms coupled with innovative cultivation techniques were utilized. Approximately 60,000 niche microbes from various habitats (slow-growing terrestrial fungi, Antarctic microbes, and mangrove endophytes) were cultivated on a small-scale, extracted, and used in high-throughput screening to determine antimalarial activity. About 1% of crude extracts were considered active and 6% partially active (≥ 67% inhibition at 5 and 50 μg/mL, respectively). Active extracts (685) were cultivated on a large-scale, fractionated, and screened for both antimalarial activity and cytotoxicity. High interest fractions (397) with an IC50 < 1.11 μg/mL were identified and subjected to chromatographic separation for compound characterization and dereplication. Identifying active compounds with nanomolar antimalarial activity coupled with a selectivity index tenfold higher was accomplished with two of the 52 compounds isolated. This microscale, high-throughput screening project for antiplasmodial agents is discussed in the context of current natural product drug discovery efforts.

  5. Miniaturized Cultivation of Microbiota for Antimalarial Drug Discovery.

    PubMed

    Waterman, Carrie; Calcul, Laurent; Beau, Jeremy; Ma, Wai Sheung; Lebar, Matthew D; von Salm, Jacqueline L; Harter, Charles; Mutka, Tina; Morton, Lindsay C; Maignan, Patrick; Barisic, Betty; van Olphen, Alberto; Kyle, Dennis E; Vrijmoed, Lilian; Pang, Ka-Lai; Pearce, Cedric J; Baker, Bill J

    2016-01-01

    The ongoing search for effective antiplasmodial agents remains essential in the fight against malaria worldwide. Emerging parasitic drug resistance places an urgent need to explore chemotherapies with novel structures and mechanisms of action. Natural products have historically provided effective antimalarial drug scaffolds. In an effort to search nature's chemical potential for antiplasmodial agents, unconventionally sourced organisms coupled with innovative cultivation techniques were utilized. Approximately 60,000 niche microbes from various habitats (slow-growing terrestrial fungi, Antarctic microbes, and mangrove endophytes) were cultivated on a small-scale, extracted, and used in high-throughput screening to determine antimalarial activity. About 1% of crude extracts were considered active and 6% partially active (≥ 67% inhibition at 5 and 50 μg/mL, respectively). Active extracts (685) were cultivated on a large-scale, fractionated, and screened for both antimalarial activity and cytotoxicity. High interest fractions (397) with an IC50 < 1.11 μg/mL were identified and subjected to chromatographic separation for compound characterization and dereplication. Identifying active compounds with nanomolar antimalarial activity coupled with a selectivity index tenfold higher was accomplished with two of the 52 compounds isolated. This microscale, high-throughput screening project for antiplasmodial agents is discussed in the context of current natural product drug discovery efforts. PMID:25545963

  6. Artemisinin anti-malarial drugs in China

    PubMed Central

    Guo, Zongru

    2016-01-01

    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. PMID:27006895

  7. Evolution from double to triple-antimalarial drug combinations.

    PubMed

    Shanks, G Dennis; Edstein, Michael D; Jacobus, David

    2015-03-01

    Drug combinations are used to treat multiple-drug resistant malaria parasites and to attempt to further delay the evolution of drug resistance. Most current antimalarial combinations are binary but it is likely that new triple drug combinations will be required in the future. A review of previous triple combinations of antimalarial drugs was done to focus attention on past problems and possible future combinations. The advantages of such triple drug combinations include greater efficacy against multiple-drug resistant strains, synergistic action between the different medications and simplification of the regimen so that it could be administered under direct observation and possibly as single-dose therapy. The disadvantages of poly-pharmacy include increased cost of medication, difficulty preparing robust regulatory packages and problems constructing combined formulations due to drug-drug interactions. Given the arrival of artemisinin tolerance/resistance in Southeast Asia, it is likely that new drugs introduced for malaria treatment will be in triple drug combinations. PMID:25549631

  8. Antimicrobial peptides: a new class of antimalarial drugs?

    PubMed Central

    Vale, Nuno; Aguiar, Luísa; Gomes, Paula

    2014-01-01

    A range of antimicrobial peptides (AMP) exhibit activity on malaria parasites, Plasmodium spp., in their blood or mosquito stages, or both. These peptides include a diverse array of both natural and synthetic molecules varying greatly in size, charge, hydrophobicity, and secondary structure features. Along with an overview of relevant literature reports regarding AMP that display antiplasmodial activity, this review makes a few considerations about those molecules as a potential new class of antimalarial drugs. PMID:25566072

  9. Quantifying the pharmacology of antimalarial drug combination therapy

    NASA Astrophysics Data System (ADS)

    Hastings, Ian M.; Hodel, Eva Maria; Kay, Katherine

    2016-09-01

    Most current antimalarial drugs are combinations of an artemisinin plus a ‘partner’ drug from another class, and are known as artemisinin-based combination therapies (ACTs). They are the frontline drugs in treating human malaria infections. They also have a public-health role as an essential component of recent, comprehensive scale-ups of malaria interventions and containment efforts conceived as part of longer term malaria elimination efforts. Recent reports that resistance has arisen to artemisinins has caused considerable concern. We investigate the likely impact of artemisinin resistance by quantifying the contribution artemisinins make to the overall therapeutic capacity of ACTs. We achieve this using a simple, easily understood, algebraic approach and by more sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two approaches gave consistent results. Surprisingly, the artemisinin component typically makes a negligible contribution (≪0.0001%) to the therapeutic capacity of the most widely used ACTs and only starts to make a significant contribution to therapeutic outcome once resistance has started to evolve to the partner drugs. The main threat to antimalarial drug effectiveness and control comes from resistance evolving to the partner drugs. We therefore argue that public health policies be re-focussed to maximise the likely long-term effectiveness of the partner drugs.

  10. Quantifying the pharmacology of antimalarial drug combination therapy.

    PubMed

    Hastings, Ian M; Hodel, Eva Maria; Kay, Katherine

    2016-01-01

    Most current antimalarial drugs are combinations of an artemisinin plus a 'partner' drug from another class, and are known as artemisinin-based combination therapies (ACTs). They are the frontline drugs in treating human malaria infections. They also have a public-health role as an essential component of recent, comprehensive scale-ups of malaria interventions and containment efforts conceived as part of longer term malaria elimination efforts. Recent reports that resistance has arisen to artemisinins has caused considerable concern. We investigate the likely impact of artemisinin resistance by quantifying the contribution artemisinins make to the overall therapeutic capacity of ACTs. We achieve this using a simple, easily understood, algebraic approach and by more sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two approaches gave consistent results. Surprisingly, the artemisinin component typically makes a negligible contribution (≪0.0001%) to the therapeutic capacity of the most widely used ACTs and only starts to make a significant contribution to therapeutic outcome once resistance has started to evolve to the partner drugs. The main threat to antimalarial drug effectiveness and control comes from resistance evolving to the partner drugs. We therefore argue that public health policies be re-focussed to maximise the likely long-term effectiveness of the partner drugs. PMID:27604175

  11. Quantifying the pharmacology of antimalarial drug combination therapy

    PubMed Central

    Hastings, Ian M.; Hodel, Eva Maria; Kay, Katherine

    2016-01-01

    Most current antimalarial drugs are combinations of an artemisinin plus a ‘partner’ drug from another class, and are known as artemisinin-based combination therapies (ACTs). They are the frontline drugs in treating human malaria infections. They also have a public-health role as an essential component of recent, comprehensive scale-ups of malaria interventions and containment efforts conceived as part of longer term malaria elimination efforts. Recent reports that resistance has arisen to artemisinins has caused considerable concern. We investigate the likely impact of artemisinin resistance by quantifying the contribution artemisinins make to the overall therapeutic capacity of ACTs. We achieve this using a simple, easily understood, algebraic approach and by more sophisticated pharmacokinetic/pharmacodynamic analyses of drug action; the two approaches gave consistent results. Surprisingly, the artemisinin component typically makes a negligible contribution (≪0.0001%) to the therapeutic capacity of the most widely used ACTs and only starts to make a significant contribution to therapeutic outcome once resistance has started to evolve to the partner drugs. The main threat to antimalarial drug effectiveness and control comes from resistance evolving to the partner drugs. We therefore argue that public health policies be re-focussed to maximise the likely long-term effectiveness of the partner drugs. PMID:27604175

  12. Antimalarial drugs for rheumatoid disease during pregnancy.

    PubMed Central

    Koren, G.

    1999-01-01

    QUESTION: One of my patients, who has rheumatoid arthritis, has just found out she is pregnant. She is being treated with hydroxychloroquine. I could not find anything about the safety of this drug during pregnancy. ANSWER: Most of the literature on this drug relates to prophylaxis for malaria. Much lower doses than those used for rheumatic diseases are given with no adverse fetal effects. Several studies on use of the drug for rheumatic diseases during pregnancy also failed to show adverse fetal effects, although, in most cases, only first-trimester exposure was reported. PMID:10626050

  13. A better resolution for integrating methods for monitoring Plasmodium falciparum resistance to antimalarial drugs.

    PubMed

    Abdul-Ghani, Rashad; Al-Maktari, Mohamed T; Al-Shibani, Latifa A; Allam, Amal F

    2014-09-01

    Effective chemotherapy is the mainstay of malaria control. However, resistance of falciparum malaria to antimalarial drugs compromised the efforts to eliminate the disease and led to the resurgence of malaria epidemics. Three main approaches are used to monitor antimalarial drug efficacy and drug resistance; namely, in vivo trials, in vitro/ex vivo assays and molecular markers of drug resistance. Each approach has its implications of use as well as its advantages and drawbacks. Therefore, there is a need to use an integrated approach that would give the utmost effect to detect resistance as early as its emergence and to track it once spread. Such integration becomes increasingly needed in the era of artemisinin-based combination therapy as a forward action to deter resistance. The existence of regional and global networks for the standardization of methodology, provision of high quality reagents for the assessment of antimalarial drug resistance and dissemination of open-access data would help in approaching an integrated resistance surveillance system on a global scale.

  14. High-throughput matrix screening identifies synergistic and antagonistic antimalarial drug combinations

    PubMed Central

    Mott, Bryan T.; Eastman, Richard T.; Guha, Rajarshi; Sherlach, Katy S.; Siriwardana, Amila; Shinn, Paul; McKnight, Crystal; Michael, Sam; Lacerda-Queiroz, Norinne; Patel, Paresma R.; Khine, Pwint; Sun, Hongmao; Kasbekar, Monica; Aghdam, Nima; Fontaine, Shaun D.; Liu, Dongbo; Mierzwa, Tim; Mathews-Griner, Lesley A.; Ferrer, Marc; Renslo, Adam R.; Inglese, James; Yuan, Jing; Roepe, Paul D.; Su, Xin-zhuan; Thomas, Craig J.

    2015-01-01

    Drug resistance in Plasmodium parasites is a constant threat. Novel therapeutics, especially new drug combinations, must be identified at a faster rate. In response to the urgent need for new antimalarial drug combinations we screened a large collection of approved and investigational drugs, tested 13,910 drug pairs, and identified many promising antimalarial drug combinations. The activity of known antimalarial drug regimens was confirmed and a myriad of new classes of positively interacting drug pairings were discovered. Network and clustering analyses reinforced established mechanistic relationships for known drug combinations and identified several novel mechanistic hypotheses. From eleven screens comprising >4,600 combinations per parasite strain (including duplicates) we further investigated interactions between approved antimalarials, calcium homeostasis modulators, and inhibitors of phosphatidylinositide 3-kinases (PI3K) and the mammalian target of rapamycin (mTOR). These studies highlight important targets and pathways and provide promising leads for clinically actionable antimalarial therapy. PMID:26403635

  15. The Oral Antimalarial Drug Tafenoquine Shows Activity against Trypanosoma brucei

    PubMed Central

    Carvalho, Luis; Martínez-García, Marta; Pérez-Victoria, Ignacio; Manzano, José Ignacio; Yardley, Vanessa

    2015-01-01

    The protozoan parasite Trypanosoma brucei causes human African trypanosomiasis, or sleeping sickness, a neglected tropical disease that requires new, safer, and more effective treatments. Repurposing oral drugs could reduce both the time and cost involved in sleeping sickness drug discovery. Tafenoquine (TFQ) is an oral antimalarial drug belonging to the 8-aminoquinoline family which is currently in clinical phase III. We show here that TFQ efficiently kills different T. brucei spp. in the submicromolar concentration range. Our results suggest that TFQ accumulates into acidic compartments and induces a necrotic process involving cell membrane disintegration and loss of cytoplasmic content, leading to parasite death. Cell lysis is preceded by a wide and multitarget drug action, affecting the lysosome, mitochondria, and acidocalcisomes and inducing a depolarization of the mitochondrial membrane potential, elevation of intracellular Ca2+, and production of reactive oxygen species. This is the first report of an 8-aminoquinoline demonstrating significant in vitro activity against T. brucei. PMID:26195527

  16. The Oral Antimalarial Drug Tafenoquine Shows Activity against Trypanosoma brucei.

    PubMed

    Carvalho, Luis; Martínez-García, Marta; Pérez-Victoria, Ignacio; Manzano, José Ignacio; Yardley, Vanessa; Gamarro, Francisco; Pérez-Victoria, José M

    2015-10-01

    The protozoan parasite Trypanosoma brucei causes human African trypanosomiasis, or sleeping sickness, a neglected tropical disease that requires new, safer, and more effective treatments. Repurposing oral drugs could reduce both the time and cost involved in sleeping sickness drug discovery. Tafenoquine (TFQ) is an oral antimalarial drug belonging to the 8-aminoquinoline family which is currently in clinical phase III. We show here that TFQ efficiently kills different T. brucei spp. in the submicromolar concentration range. Our results suggest that TFQ accumulates into acidic compartments and induces a necrotic process involving cell membrane disintegration and loss of cytoplasmic content, leading to parasite death. Cell lysis is preceded by a wide and multitarget drug action, affecting the lysosome, mitochondria, and acidocalcisomes and inducing a depolarization of the mitochondrial membrane potential, elevation of intracellular Ca(2+), and production of reactive oxygen species. This is the first report of an 8-aminoquinoline demonstrating significant in vitro activity against T. brucei. PMID:26195527

  17. Poor quality vital anti-malarials in Africa - an urgent neglected public health priority

    PubMed Central

    2011-01-01

    Background Plasmodium falciparum malaria remains a major public health problem. A vital component of malaria control rests on the availability of good quality artemisinin-derivative based combination therapy (ACT) at the correct dose. However, there are increasing reports of poor quality anti-malarials in Africa. Methods Seven collections of artemisinin derivative monotherapies, ACT and halofantrine anti-malarials of suspicious quality were collected in 2002/10 in eleven African countries and in Asia en route to Africa. Packaging, chemical composition (high performance liquid chromatography, direct ionization mass spectrometry, X-ray diffractometry, stable isotope analysis) and botanical investigations were performed. Results Counterfeit artesunate containing chloroquine, counterfeit dihydroartemisinin (DHA) containing paracetamol (acetaminophen), counterfeit DHA-piperaquine containing sildenafil, counterfeit artemether-lumefantrine containing pyrimethamine, counterfeit halofantrine containing artemisinin, and substandard/counterfeit or degraded artesunate and artesunate+amodiaquine in eight countries are described. Pollen analysis was consistent with manufacture of counterfeits in eastern Asia. These data do not allow estimation of the frequency of poor quality anti-malarials in Africa. Conclusions Criminals are producing diverse harmful anti-malarial counterfeits with important public health consequences. The presence of artesunate monotherapy, substandard and/or degraded and counterfeit medicines containing sub-therapeutic amounts of unexpected anti-malarials will engender drug resistance. With the threatening spread of artemisinin resistance to Africa, much greater investment is required to ensure the quality of ACTs and removal of artemisinin monotherapies. The International Health Regulations may need to be invoked to counter these serious public health problems. PMID:22152094

  18. Antimalarial drug resistance in Bangladesh, 1996-2012.

    PubMed

    Haque, Ubydul; Glass, Gregory E; Haque, Waziul; Islam, Nazrul; Roy, Shyamal; Karim, Jahirul; Noedl, Harald

    2013-12-01

    Malaria remains an important health problem in Bangladesh, with approximately 14 million people at risk. Antimalarial drug resistance is a major obstacle to the control of malaria in endemic countries. In 2012, Bangladesh reported an estimated 29 522 malaria episodes, of which 94% were reported as being caused by Plasmodium falciparum. In this study, we reviewed and summarized antimalarial drug resistance data from Bangladesh published until June 2013. We searched published sources for data referring to any type of P. falciparum drug resistance (in vivo, in vitro, or molecular) and found 169 articles published in peer-reviewed journals. Of these, 143 articles were excluded because they did not meet our inclusion criteria. After detailed review of the remaining 26 articles, 14 were selected for evaluation. Published studies indicate that P. falciparum shows varying levels of resistance to chloroquine, mefloquine and sulfadoxine-pyrimethamine. Combination therapy of chloroquine and primaquine has proven ineffective and combinations of sulfadoxine-pyrimethamine with either quinine or chloroquine have also shown poor efficacy. Recent studies indicate that artemisinin derivatives, such as artesunate, remain highly efficacious in treating P. falciparum malaria. Available data suggest that artemisinins, quinine, doxycyline, mefloquine-artesunate and azithromycin-artesunate combination therapy remain efficacious in the treatment of P. falciparum malaria in Bangladesh.

  19. Long term effectiveness of antimalarial drugs in rheumatic diseases

    PubMed Central

    Avina-Zubieta, J; Galindo-Rodriguez, G.; Newman, S.; Suarez-Almazor, M.; Russell, A.

    1998-01-01

    OBJECTIVE—The purpose of this study was to compare the long term effectiveness between chloroquine (CQ) and hydroxychloroquine (HCQ).
METHODS—Medical charts of all patients seen by eight rheumatologists practising in two tertiary care centres and starting antimalarial treatment between January 1985 and December 1993 were reviewed. Patient characteristics, disease, and treatment information were collected. The main outcome measures were the cause of and the time to the discontinuation of antimalarial drugs resulting from all causes, principally toxicity or inefficacy, or both. Bivariate analysis including t tests and χ2 tests were used to assess differences between means and proportions respectively. Survival curves were evaluated using the Kaplan-Meier method. Multivariate analysis (Cox regression) was used to adjust for potential confounders.
RESULTS—After all medical records were reviewed, 1042 eligible cases were identified. From these, 940 (90%) had usable information and they represent the cohort. Five hundred and fifty eight had rheumatoid arthritis, 178 had systemic lupus erythematosus, 127 had palindromic arthritis, and 77 had other diagnoses. Fifty seven per cent of the patients received CQ and 43% HCQ. The proportion of patients with side effects taking HCQ and CQ was 15% and 28% respectively (p=0.001). Using Cox regression model to adjust for age at the onset of antimalarial treatment, physician differences, sex, disease type, disease duration before treatment, and rank selection, there were no differences in the hazard ratio (HR) for overall discontinuations between CQ and HCQ. While the HR for discontinuations because of toxicity was lower for HCQ (HR= 0.6, 95% CI 0.4, 0.9), the HR for discontinuations because of inefficacy was significantly higher for HCQ (HR= 1.4, 95% CI 1.1, 1.9).
CONCLUSIONS—After adjusting for time and several confounders HCQ was less toxic but less effective than CQ. Only one case of probable

  20. Toxic effects of antimalarial drugs in Paramecium: role of calcium channels.

    PubMed

    Nori, V S; Barry, S R

    1997-05-01

    The antimalarial drugs, quinacrine, quinine and mefloquine, as well as the structurally-similar compound, W-7, inhibit calcium-dependent backward swimming and calcium currents in Paramecium calkinsi. These drugs are also toxic to paramecia at high concentrations. Therefore, one site of toxic action of the drugs may be the calcium channel. To test this hypothesis, the toxicity of the antimalarials and W-7 was compared in paramecia with and without calcium channels. Since calcium channels are located on the cilia, calcium channels were removed from the paramecia by deciliating the cells. Deciliated cells were found to be less susceptible to the lethal effects of the antimalarials and W-7 than their ciliated counterparts. Moreover, Pawns, mutants of P. tetraurelia that possess cilia but lack functional calcium channels, were also less susceptible to the antimalarials than wild-type cells. Thus, calcium channels may be one site of toxic action of the antimalarial drugs in paramecia and perhaps in other protists.

  1. Paper Test Cards for Presumptive Testing of Very Low Quality Antimalarial Medications

    PubMed Central

    Weaver, Abigail A.; Lieberman, Marya

    2015-01-01

    Carrying out chemical analysis of antimalarials to detect low-quality medications before they reach a patient is a costly venture. Here, we show that a library of chemical color tests embedded on a paper card can presumptively identify formulations corresponding to very low quality antimalarial drugs. The presence or absence of chloroquine (CQ), doxycycline (DOX), quinine, sulfadoxine, pyrimethamine, and primaquine antimalarial medications, in addition to fillers used in low-quality pharmaceuticals, are indicated by patterns of colors that are generated on the test cards. Test card sensitivity for detection of these pure components ranges from 90% to 100% with no false positives in the absence of pharmaceutical. The color intensities from reactions characteristic of CQ or DOX allowed visual detection of formulations of these medications cut with 60% or 100% filler, although samples cut with 30% filler could not be reliably detected colorimetrically. However, the addition of unexpected fillers, even in 30% quantities, or substitute pharmaceuticals, could sometimes be detected by other color reactions on the test cards. Tests are simple and inexpensive enough to be carried out in clinics, pharmacies, and ports of entry and could provide a screening method to presumptively indicate very low quality medicines throughout the supply chain. PMID:25897064

  2. Paper test cards for presumptive testing of very low quality antimalarial medications.

    PubMed

    Weaver, Abigail A; Lieberman, Marya

    2015-06-01

    Carrying out chemical analysis of antimalarials to detect low-quality medications before they reach a patient is a costly venture. Here, we show that a library of chemical color tests embedded on a paper card can presumptively identify formulations corresponding to very low quality antimalarial drugs. The presence or absence of chloroquine (CQ), doxycycline (DOX), quinine, sulfadoxine, pyrimethamine, and primaquine antimalarial medications, in addition to fillers used in low-quality pharmaceuticals, are indicated by patterns of colors that are generated on the test cards. Test card sensitivity for detection of these pure components ranges from 90% to 100% with no false positives in the absence of pharmaceutical. The color intensities from reactions characteristic of CQ or DOX allowed visual detection of formulations of these medications cut with 60% or 100% filler, although samples cut with 30% filler could not be reliably detected colorimetrically. However, the addition of unexpected fillers, even in 30% quantities, or substitute pharmaceuticals, could sometimes be detected by other color reactions on the test cards. Tests are simple and inexpensive enough to be carried out in clinics, pharmacies, and ports of entry and could provide a screening method to presumptively indicate very low quality medicines throughout the supply chain. PMID:25897064

  3. The antimalarial drug quinine interferes with serotonin biosynthesis and action.

    PubMed

    Islahudin, Farida; Tindall, Sarah M; Mellor, Ian R; Swift, Karen; Christensen, Hans E M; Fone, Kevin C F; Pleass, Richard J; Ting, Kang-Nee; Avery, Simon V

    2014-01-01

    The major antimalarial drug quinine perturbs uptake of the essential amino acid tryptophan, and patients with low plasma tryptophan are predisposed to adverse quinine reactions; symptoms of which are similar to indications of tryptophan depletion. As tryptophan is a precursor of the neurotransmitter serotonin (5-HT), here we test the hypothesis that quinine disrupts serotonin function. Quinine inhibited serotonin-induced proliferation of yeast as well as human (SHSY5Y) cells. One possible cause of this effect is through inhibition of 5-HT receptor activation by quinine, as we observed here. Furthermore, cells exhibited marked decreases in serotonin production during incubation with quinine. By assaying activity and kinetics of the rate-limiting enzyme for serotonin biosynthesis, tryptophan hydroxylase (TPH2), we showed that quinine competitively inhibits TPH2 in the presence of the substrate tryptophan. The study shows that quinine disrupts both serotonin biosynthesis and function, giving important new insight to the action of quinine on mammalian cells.

  4. Modulation of PF10_0355 (MSPDBL2) Alters Plasmodium falciparum Response to Antimalarial Drugs

    PubMed Central

    Van Tyne, Daria; Uboldi, Alessandro D.; Healer, Julie; Cowman, Alan F.

    2013-01-01

    Malaria's ability to rapidly adapt to new drugs has allowed it to remain one of the most devastating infectious diseases of humans. Understanding and tracking the genetic basis of these adaptations are critical to the success of treatment and intervention strategies. The novel antimalarial resistance locus PF10_0355 (Pfmspdbl2) was previously associated with the parasite response to halofantrine, and functional validation confirmed that overexpression of this gene lowered parasite sensitivity to both halofantrine and the structurally related antimalarials mefloquine and lumefantrine, predominantly through copy number variation. Here we further characterize the role of Pfmspdbl2 in mediating the antimalarial drug response of Plasmodium falciparum. Knockout of Pfmspdbl2 increased parasite sensitivity to halofantrine, mefloquine, and lumefantrine but not to unrelated antimalarials, further suggesting that this gene mediates the parasite response to a specific class of antimalarial drugs. A single nucleotide polymorphism encoding a C591S mutation within Pfmspdbl2 had the strongest association with halofantrine sensitivity and showed a high derived allele frequency among Senegalese parasites. Transgenic parasites expressing the ancestral Pfmspdbl2 allele were more sensitive to halofantrine and structurally related antimalarials than were parasites expressing the derived allele, revealing an allele-specific effect on drug sensitivity in the absence of copy number effects. Finally, growth competition experiments showed that under drug pressure, parasites expressing the derived allele of Pfmspdbl2 outcompeted parasites expressing the ancestral allele within a few generations. Together, these experiments demonstrate that modulation of Pfmspdbl2 affects malaria parasite responses to antimalarial drugs. PMID:23587962

  5. Assessment of urinary excretion of antimalarial drugs in large-scale chemotherapeutic eradication projects

    PubMed Central

    Bruce-Chwatt, L. J.

    1959-01-01

    Assessment of the urinary excretion of an antimalarial drug is a useful means of checking the amount of drug administered and the regularity of intake. The author describes the various methods available for the qualitative and quantitative estimation of antimalarial drugs in urine and discusses their relative merits, with special reference to their suitability for use in the field. He points out the difficulties involved in estimating the urinary excretion of antimalarials in large-scale chemotherapeutic eradication projects and stress the importance of simplifying testing techniques as far as possible. PMID:13805135

  6. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network

    PubMed Central

    Cui, Liwang; Mharakurwa, Sungano; Ndiaye, Daouda; Rathod, Pradipsinh K.; Rosenthal, Philip J.

    2015-01-01

    Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs. PMID:26259943

  7. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network.

    PubMed

    Cui, Liwang; Mharakurwa, Sungano; Ndiaye, Daouda; Rathod, Pradipsinh K; Rosenthal, Philip J

    2015-09-01

    Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs. PMID:26259943

  8. Superinfection and the evolution of resistance to antimalarial drugs.

    PubMed

    Klein, Eili Y; Smith, David L; Laxminarayan, Ramanan; Levin, Simon

    2012-09-22

    A major issue in the control of malaria is the evolution of drug resistance. Ecological theory has demonstrated that pathogen superinfection and the resulting within-host competition influences the evolution of specific traits. Individuals infected with Plasmodium falciparum are consistently infected by multiple parasites; however, while this probably alters the dynamics of resistance evolution, there are few robust mathematical models examining this issue. We developed a general theory for modelling the evolution of resistance with host superinfection and examine: (i) the effect of transmission intensity on the rate of resistance evolution; (ii) the importance of different biological costs of resistance; and (iii) the best measure of the frequency of resistance. We find that within-host competition retards the ability and slows the rate at which drug-resistant parasites invade, particularly as the transmission rate increases. We also find that biological costs of resistance that reduce transmission are less important than reductions in the duration of drug-resistant infections. Lastly, we find that random sampling of the population for resistant parasites is likely to significantly underestimate the frequency of resistance. Considering superinfection in mathematical models of antimalarial drug resistance may thus be important for generating accurate predictions of interventions to contain resistance.

  9. Superinfection and the evolution of resistance to antimalarial drugs

    PubMed Central

    Klein, Eili Y.; Smith, David L.; Laxminarayan, Ramanan; Levin, Simon

    2012-01-01

    A major issue in the control of malaria is the evolution of drug resistance. Ecological theory has demonstrated that pathogen superinfection and the resulting within-host competition influences the evolution of specific traits. Individuals infected with Plasmodium falciparum are consistently infected by multiple parasites; however, while this probably alters the dynamics of resistance evolution, there are few robust mathematical models examining this issue. We developed a general theory for modelling the evolution of resistance with host superinfection and examine: (i) the effect of transmission intensity on the rate of resistance evolution; (ii) the importance of different biological costs of resistance; and (iii) the best measure of the frequency of resistance. We find that within-host competition retards the ability and slows the rate at which drug-resistant parasites invade, particularly as the transmission rate increases. We also find that biological costs of resistance that reduce transmission are less important than reductions in the duration of drug-resistant infections. Lastly, we find that random sampling of the population for resistant parasites is likely to significantly underestimate the frequency of resistance. Considering superinfection in mathematical models of antimalarial drug resistance may thus be important for generating accurate predictions of interventions to contain resistance. PMID:22787024

  10. Targeting Plasmodium Metabolism to Improve Antimalarial Drug Design.

    PubMed

    Avitia-Domínguez, Claudia; Sierra-Campos, Erick; Betancourt-Conde, Irene; Aguirre-Raudry, Miriam; Vázquez-Raygoza, Alejandra; Luevano-De la Cruz, Artemisa; Favela-Candia, Alejandro; Sarabia-Sanchez, Marie; Ríos-Soto, Lluvia; Méndez-Hernández, Edna; Cisneros-Martínez, Jorge; Palacio-Gastélum, Marcelo Gómez; Valdez-Solana, Mónica; Hernández-Rivera, Jessica; De Lira-Sánchez, Jaime; Campos-Almazán, Mara; Téllez-Valencia, Alfredo

    2016-01-01

    Malaria is one of the main infectious diseases in tropical developing countries and represents high morbidity and mortality rates nowadays. The principal etiological agent P. falciparum is transmitted through the bite of the female Anopheles mosquito. The issue has escalated due to the emergence of resistant strains to most of the antimalarials used for the treatment including Chloroquine, Sulfadoxine-Pyrimethamine, and recently Artemisinin derivatives, which has led to diminished effectiveness and by consequence increased the severity of epidemic outbreaks. Due to the lack of effective compounds to treat these drug-resistant strains, the discovery or development of novel anti-malaria drugs is important. In this context, one strategy has been to find inhibitors of enzymes, which play an important role for parasite survival. Today, promising results have been obtained in this regard, involving the entire P. falciparum metabolism. These inhibitors could serve as leads in the search of a new chemotherapy against malaria. This review focuses on the achievements in recent years with regard to inhibition of enzymes used as targets for drug design against malaria. PMID:26983887

  11. Next-Generation Antimalarial Drugs: Hybrid Molecules as a New Strategy in Drug Design

    PubMed Central

    Muregi, Francis W; Ishih, Akira

    2010-01-01

    Malaria is a disease that affects nearly 40% of the global population, and chemotherapy remains the mainstay of its control strategy. The global malaria situation is increasingly being exacerbated by the emergence of drug resistance to most of the available antimalarials, necessitating search for novel drugs. A recent rational approach of antimalarial drug design characterized as “covalent bitherapy” involves linking two molecules with individual intrinsic activity into a single agent, thus packaging dual-activity into a single hybrid molecule. Current research in this field seems to endorse hybrid molecules as the next-generation antimalarial drugs. If the selective toxicity of hybrid prodrugs can be demonstrated in vivo with good bioavailability at the target site in the parasite, it would offer various advantages including dosage compliance, minimized toxicity, ability to design better drug combinations, and cheaper preclinical evaluation while achieving the ultimate object of delaying or circumventing the development of resistance. This review is focused on several hybrid molecules that have been developed, with particular emphasis on those deemed to have high potential for development for clinical use. Drug Dev Res 71: 20–32, 2010. © 2009 Wiley-Liss, Inc. PMID:21399701

  12. Perspective for the production of antimalarial drugs in Brazil.

    PubMed

    Gilbert, B

    1992-01-01

    There appears to be no chemical manufacture of antimalarial drugs in Brazil. Technology at the laboratory process level has been developed for chloroquine, mefloquine, pyrimethamine and cycloguanil, but not perfected nor scaled-up, largely for economic reasons and market uncertainty. Development of primaquine has been contracted but it will run into the same difficulty. Manufacturing capacity for sulfadoxine was registered in the SDI by Roche. A project to produce artemisinine and its derivatives is under way at UNICAMP-CPQBA but is hampered by low content in the plant. Proguanil could be produced easily, but apparently no attempt has been made to do so. Quinine is imported on a large scale mostly for soft-drink production. Since malarial treatment falls largely within the responsibility of the Government health authorities, manufacture of drugs in Brazil will depend on an assured medium-term purchase order made to a potential local manufacturer, since competition in the world market is scarcely viable at the present moment.

  13. Estimated under-five deaths associated with poor-quality antimalarials in sub-Saharan Africa.

    PubMed

    Renschler, John P; Walters, Kelsey M; Newton, Paul N; Laxminarayan, Ramanan

    2015-06-01

    Many antimalarials sold in sub-Saharan Africa are poor-quality (falsified, substandard, or degraded), and the burden of disease caused by this problem is inadequately quantified. In this article, we estimate the number of under-five deaths caused by ineffective treatment of malaria associated with consumption of poor-quality antimalarials in 39 sub-Saharan countries. Using Latin hypercube sampling our estimates were calculated as the product of the number of private sector antimalarials consumed by malaria-positive children in 2013; the proportion of private sector antimalarials consumed that were of poor-quality; and the case fatality rate (CFR) of under-five malaria-positive children who did not receive appropriate treatment. An estimated 122,350 (interquartile range [IQR]: 91,577-154,736) under-five malaria deaths were associated with consumption of poor-quality antimalarials, representing 3.75% (IQR: 2.81-4.75%) of all under-five deaths in our sample of 39 countries. There is considerable uncertainty surrounding our results because of gaps in data on case fatality rates and prevalence of poor-quality antimalarials. Our analysis highlights the need for further investigation into the distribution of poor-quality antimalarials and the need for stronger surveillance and regulatory efforts to prevent the sale of poor-quality antimalarials. PMID:25897068

  14. Simple Field Assays to Check Quality of Current Artemisinin-Based Antimalarial Combination Formulations

    PubMed Central

    Ioset, Jean-Robert; Kaur, Harparkash

    2009-01-01

    Introduction Malaria continues to be one of the major public health problems in Africa, Asia and Latin America. Artemisinin derivatives (ARTs; artesunate, artemether, and dihydroartemisinin) derived from the herb, Artemisia annua, are the most effective antimalarial drugs available providing rapid cures. The World Health Organisation (WHO) has recommended that all antimalarials must be combined with an artemisinin component (artemisinin-based combination therapy; ACT) for use as first line treatment against malaria. This class of drugs is now first-line policy in most malaria-endemic countries. Reports of ad hoc surveys from South East Asia show that up to 50% of the artesunate currently sold is counterfeit. Drug quality is rarely assessed in resource poor countries in part due to lack of dedicated laboratory facilities which are expensive to build, equip and maintain. With a view to address this unmet need we developed two novel colour reaction assays that can be used in the field to check the quality of ARTs. Methods and Findings Our assays utilise thin layer chromatography silica gel sheets and 2, 4 dinitrophenylhydrazine or 4-Benzoylamino-2, 5-dimethoxybenzenediazonium chloride hemi (zinc chloride) salt as the reagents showing a pink or blue product respectively only in the presence ARTs. We are able to detect as low as 10% of ARTs in ACTs (WINTHROP - artesunate/amodiaquine, Coartem®-artemether/lumefantrine and Duocortexcin - dihydroartemisinin/piperaquine). The assays have been validated extensively by testing eighty readily accessible and widely used drugs in malaria endemic countries. None of the other antimalarial drugs or a range of commonly used excipients, antiretroviral drugs or other frequently used drugs from the WHO essential drugs list such as analgesics or antibiotics are detected with our assays. Conclusions Our two independent assays requiring no specialist training are specific, simple to use, rapid, robust, reproducible, inexpensive and, have

  15. Collaborative Health and Enforcement Operations on the Quality of Antimalarials and Antibiotics in Southeast Asia

    PubMed Central

    Yong, Yuk Lin; Plançon, Aline; Lau, Yen Hui; Hostetler, Dana M.; Fernández, Facundo M.; Green, Michael D.; Sounvoravong, Sourisak; Nara, Suon; Boravann, Mam; Dumrong, Thitikornkovit; Bangsawan, Nurjaya; Low, Min Yong; Lim, Chin-Chin; Ai, Ruth Lee Choo; Newton, Paul N.

    2015-01-01

    Counterfeit (or falsified) and substandard medicines pose a major public health risk. We describe the findings of Operation Storm I and II conducted in 2008–2009 to combat counterfeit medicines through partnership between national customs, Drug Regulatory Agencies (DRAs), and police in Cambodia, Indonesia, Laos, Myanmar, Singapore, Thailand, and Vietnam. Samples were obtained from seizures and market surveillance by national DRAs. Laboratory analysis using spectroscopic and chromatographic techniques and examination of packaging were performed. Ninety-three suspect antibiotics and 95 antimalarial samples were collected. Of the 93 antibiotics, 29 (31%) had % active pharmaceutical ingredient content (%API) < 85% or > 115% (including one counterfeit). Of the 95 antimalarials, 30 (32%) had %API < 85 > 115% API (including one counterfeit). A significant minority of samples, antimalarials (13%) and antibiotics (15%), were collected in plastic bags with minimal or no labeling. Of 20 ampicillin samples, 13 (65%) contained < 85% API (with one counterfeit containing additional amoxicillin). Of 34 oral artesunate samples, 7 (21%) contained %API out of the 85–115% range. Coordinated and synergistic partnership adopted by the participating countries, International Criminal Police Organization (INTERPOL), World Health Organization (WHO), and laboratories facilitated a platform for discussions and intelligence sharing, helping to improve each participating country's capacity to combat poor-quality medicines. PMID:25897069

  16. Collaborative health and enforcement operations on the quality of antimalarials and antibiotics in southeast Asia.

    PubMed

    Yong, Yuk Lin; Plançon, Aline; Lau, Yen Hui; Hostetler, Dana M; Fernández, Facundo M; Green, Michael D; Sounvoravong, Sourisak; Nara, Suon; Boravann, Mam; Dumrong, Thitikornkovit; Bangsawan, Nurjaya; Low, Min Yong; Lim, Chin-Chin; Ai, Ruth Lee Choo; Newton, Paul N

    2015-06-01

    Counterfeit (or falsified) and substandard medicines pose a major public health risk. We describe the findings of Operation Storm I and II conducted in 2008-2009 to combat counterfeit medicines through partnership between national customs, Drug Regulatory Agencies (DRAs), and police in Cambodia, Indonesia, Laos, Myanmar, Singapore, Thailand, and Vietnam. Samples were obtained from seizures and market surveillance by national DRAs. Laboratory analysis using spectroscopic and chromatographic techniques and examination of packaging were performed. Ninety-three suspect antibiotics and 95 antimalarial samples were collected. Of the 93 antibiotics, 29 (31%) had % active pharmaceutical ingredient content (%API) < 85% or > 115% (including one counterfeit). Of the 95 antimalarials, 30 (32%) had %API < 85 > 115% API (including one counterfeit). A significant minority of samples, antimalarials (13%) and antibiotics (15%), were collected in plastic bags with minimal or no labeling. Of 20 ampicillin samples, 13 (65%) contained < 85% API (with one counterfeit containing additional amoxicillin). Of 34 oral artesunate samples, 7 (21%) contained %API out of the 85-115% range. Coordinated and synergistic partnership adopted by the participating countries, International Criminal Police Organization (INTERPOL), World Health Organization (WHO), and laboratories facilitated a platform for discussions and intelligence sharing, helping to improve each participating country's capacity to combat poor-quality medicines. PMID:25897069

  17. Collaborative health and enforcement operations on the quality of antimalarials and antibiotics in southeast Asia.

    PubMed

    Yong, Yuk Lin; Plançon, Aline; Lau, Yen Hui; Hostetler, Dana M; Fernández, Facundo M; Green, Michael D; Sounvoravong, Sourisak; Nara, Suon; Boravann, Mam; Dumrong, Thitikornkovit; Bangsawan, Nurjaya; Low, Min Yong; Lim, Chin-Chin; Ai, Ruth Lee Choo; Newton, Paul N

    2015-06-01

    Counterfeit (or falsified) and substandard medicines pose a major public health risk. We describe the findings of Operation Storm I and II conducted in 2008-2009 to combat counterfeit medicines through partnership between national customs, Drug Regulatory Agencies (DRAs), and police in Cambodia, Indonesia, Laos, Myanmar, Singapore, Thailand, and Vietnam. Samples were obtained from seizures and market surveillance by national DRAs. Laboratory analysis using spectroscopic and chromatographic techniques and examination of packaging were performed. Ninety-three suspect antibiotics and 95 antimalarial samples were collected. Of the 93 antibiotics, 29 (31%) had % active pharmaceutical ingredient content (%API) < 85% or > 115% (including one counterfeit). Of the 95 antimalarials, 30 (32%) had %API < 85 > 115% API (including one counterfeit). A significant minority of samples, antimalarials (13%) and antibiotics (15%), were collected in plastic bags with minimal or no labeling. Of 20 ampicillin samples, 13 (65%) contained < 85% API (with one counterfeit containing additional amoxicillin). Of 34 oral artesunate samples, 7 (21%) contained %API out of the 85-115% range. Coordinated and synergistic partnership adopted by the participating countries, International Criminal Police Organization (INTERPOL), World Health Organization (WHO), and laboratories facilitated a platform for discussions and intelligence sharing, helping to improve each participating country's capacity to combat poor-quality medicines.

  18. Falsified antimalarials: a minireview.

    PubMed

    Chaccour, Carlos; Kaur, Harparkash; Del Pozo, Jose Luis

    2015-04-01

    Malaria is a curable disease, provided timely access to efficacious drugs is sought. Poor quality and, in particular, falsified antimalarial drugs harm the population of malaria endemic areas; they put lives in peril, cause economic losses to patients, families, industry, and generally undermine the trust in health systems. The extent of the problem is not easily assessed, and although a prevalence of up to 35% of poor-quality antimalarials has been reported, this number should be interpreted with caution given the heterogeneity of methods used to measure it. The trade in falsified antimalarials can be curtailed by putting in place drug quality surveillance, better legislation and improving the access and affordability of these essential drugs. PMID:25683870

  19. Development of a Specific Monoclonal Antibody-Based ELISA to Measure the Artemether Content of Antimalarial Drugs

    PubMed Central

    He, Lishan; Zhang, Liang; Cao, Zhen; Zhang, Wei; Zhang, Rui; Tan, Guiyu; Wang, Baomin; Cui, Liwang

    2013-01-01

    Artemether is one of the artemisinin derivatives that are active ingredients in antimalarial drugs. Counterfeit and substandard antimalarial drugs have become a serious problem, which demands reliable analytical tools and implementation of strict regulation of drug quality. Structural similarity among artemisinin analogs is a challenge to develop immunoassays that are specific to artemisinin derivatives. To produce specific antibodies to artemether, we used microbial fermentation of artemether to obtain 9-hydroxyartemether, which was subsequently used to prepare a 9-O-succinylartemether hapten for conjugation with ovalbumin as the immunogen. A monoclonal antibody (mAb), designated as 2G12E1, was produced with high specificity to artemether. 2G12E1 showed low cross reactivities to dihydroartemisinin, artemisinin, artesunate and other major antimalarial drugs. An indirect competitive enzyme linked immunosorbent assay (icELISA) developed showed a concentration causing 50% of inhibition for artemether as 3.7 ng mL−1 and a working range of 0.7–19 ng mL−1. The icELISA was applied for determination of artemether content in different commercial drugs and the results were comparable to those determined by high-performance liquid chromatography analysis. In comparison with reported broad cross activity of anti-artemisinin mAbs, the most notable advantage of the 2G12E1-based ELISA is its high specificity to artemether only. PMID:24236102

  20. Retinal toxicity induced by antimalarial drugs: literature review and case report.

    PubMed

    Garza-Leon, Manuel; Flores-Alvarado, Diana Elsa; Muñoz-Bravo, Juan Manuel

    2016-06-17

    Antimalarial drugs are widely used in several countries for control of rheumatologic diseases such as systemic lupus erythematosus and rheumatoid arthritis. They are still used in Mexico because of their low cost and few secondary effects, most of which are mild and reversible. Even so, at an ophthalmological level, they could produce irreversible visual damage, which is why it is important to have ophthalmological evaluation and proper follow up. We present a clinical case as an example of characteristic ophthalmological findings as well as risk factors for retinal toxicity. We then discuss guidelines for diagnosis and follow up of patients who use antimalarial drugs for the treatment of rheumatologic illnesses.

  1. A reaction-diffusion system modeling the spread of resistance to an antimalarial drug.

    PubMed

    Bacaer, Nicolas; Sokhna, Cheikh

    2005-04-01

    A mathematical model representing the difusion of resistance to an antimalarial drug is developed. Resistance can spread only when the basic reproduction number of the resistant parasites is bigger than the basic reproduction number of the sensitive parasites (which depends on the fraction of infected people treated with the antimalarial drug). Based on a linearization study and on numerical simulations, an expression for the speed at which resistance spreads is conjectured. It depends on the ratio of the two basic reproduction numbers, on a coefficient representing the difusion of mosquitoes, on the death rate of mosquitoes infected by resistant parasites, and on the recovery rate of nonimmune humans infected by resistant parasites.

  2. Retinal toxicity induced by antimalarial drugs: literature review and case report.

    PubMed

    Garza-Leon, Manuel; Flores-Alvarado, Diana Elsa; Muñoz-Bravo, Juan Manuel

    2016-01-01

    Antimalarial drugs are widely used in several countries for control of rheumatologic diseases such as systemic lupus erythematosus and rheumatoid arthritis. They are still used in Mexico because of their low cost and few secondary effects, most of which are mild and reversible. Even so, at an ophthalmological level, they could produce irreversible visual damage, which is why it is important to have ophthalmological evaluation and proper follow up. We present a clinical case as an example of characteristic ophthalmological findings as well as risk factors for retinal toxicity. We then discuss guidelines for diagnosis and follow up of patients who use antimalarial drugs for the treatment of rheumatologic illnesses. PMID:27391903

  3. Rational Design of Antimalarial Drugs Using Molecular Modeling and Statistical Analysis.

    PubMed

    Santos, Cleydson Breno Rodrigues dos; Lobato, Cleison Carvalho; Braga, Francinaldo Sarges; Costa, Josivan da Silva; Favacho, Hugo Alexandre Silva; Carvalho, Jose Carlos Tavares; Macedo, Williams Jorge da Cruz; Brasil, Davi Do Socorro Barros; Silva, Carlos Henrique Tomich de Paula da; Silva Hage-Melim, Lorane Izabel da

    2015-01-01

    Artemisinin is an antimalarial compound isolated from Artemisia annua L. that is effective against Plasmodium falciparum. This paper proposes the development of new antimalarial derivatives of artemisinin from a SAR study and statistical analysis by multiple linear regression (MLR). The HF/6-31G** method was used to determine the molecular properties of artemisinin and 10 derivatives with antimalarial action. MEP maps and molecular docking were used to study the interface between ligand and receptor (heme). The Pearson correlation was used to choose the most important properties interrelated to the antimalarial activity: Hydration Energy (HE), Energy of the Complex (Ecplex), bond length (FeO1), and maximum index of R/Electronegativity of Sanderson (RTe+). After the Pearson correlation, 72 MLR models were built between antimalarial activity and molecular properties; the statistical quality of the models was evaluated by means of correlation coefficient (r), squared correlation coefficient (r(2)), explained variance (adjusted R(2)), standard error of estimate (SEE), and variance ratio (F), and only four models showed predictive ability. The selected models were used to predict the antimalarial activity of ten new artemisinin derivatives (test set) with unknown activity, and only eight of these compounds were predicted to be more potent than artemisinin, and were therefore subjected to theoretical studies of pharmacokinetic and toxicological properties. The test set showed satisfactory results for six new artemisinin compounds which is a promising factor for future synthesis and biological assays. PMID:26017698

  4. Monitoring antimalarial drug resistance: Applying lessons learned from the past in a fast-moving present.

    PubMed

    Sibley, Carol Hopkins; Price, Ric N

    2012-12-01

    The need for robust surveillance of antimalarial drugs is more urgent than it has ever been. In the western region of Cambodia, artemisinin resistance has emerged in Plasmodium falciparum and threatens to undermine the efficacy of highly effective artemisinin combination therapies. Although some manfestations of artemisinin tolerance are unique to this class of drug, many of its properties mirror previous experience in understanding and tracking resistance to other antimalarials. In this review we outline the spectrum of approaches that were developed to understand the evolution and spread of antifolate resistance, highlighting the importance of integrating information from different methodologies towards a better understanding of the underlying biologic processes. We consider how to apply our experience in investigating and attempting to contain antifolate resistance to inform our prospective assessment of novel antimalarial resistance patterns and their subsequent spread.

  5. Rational Design of Proteasome Inhibitors as Antimalarial Drugs.

    PubMed

    Le Chapelain, Camille; Groll, Michael

    2016-05-23

    One life, two strategies: Crucial structural differences between the human and the Plasmodium falciparum proteasomes were recently identified. A combination of cryo-EM and functional characterization enabled the design of a selective antimalarial proteasome inhibitor that shows low toxicity in the host. When used with artemisinin, this ligand offers a new approach for the efficient treatment of malaria at all stages of the parasite lifecycle.

  6. Formation of the diuretic chlorazanil from the antimalarial drug proguanil--implications for sports drug testing.

    PubMed

    Thevis, Mario; Geyer, Hans; Thomas, Andreas; Tretzel, Laura; Bailloux, Isabelle; Buisson, Corinne; Lasne, Francoise; Schaefer, Maximilian S; Kienbaum, Peter; Mueller-Stoever, Irmela; Schänzer, Wilhelm

    2015-11-10

    Chlorazanil (Ordipan, N-(4-chlorophenyl)-1,3,5-triazine-2,4-diamine) is a diuretic agent and as such prohibited in sport according to the regulations of the World Anti-Doping Agency (WADA). Despite its introduction into clinical practice in the late 1950s, the worldwide very first two adverse analytical findings were registered only in 2014, being motive for an in-depth investigation of these cases. Both individuals denied the intake of the drug; however, the athletes did declare the use of the antimalarial prophylactic agent proguanil due to temporary residences in African countries. A structural similarity between chlorazanil and proguanil is given but no direct metabolic relation has been reported in the scientific literature. Moreover, chlorazanil has not been confirmed as a drug impurity of proguanil. Proguanil however is metabolized in humans to N-(4-chlorophenyl)-biguanide, which represents a chemical precursor in the synthesis of chlorazanil. In the presence of formic acid, formaldehyde, or formic acid esters, N-(4-chlorophenyl)-biguanide converts to chlorazanil. In order to probe for potential sources of the chlorazanil detected in the doping control samples, drug formulations containing proguanil and urine samples of individuals using proguanil as antimalarial drug were subjected to liquid chromatography-high resolution/high accuracy mass spectrometry. In addition, in vitro simulations with 4-chlorophenyl-biguanide and respective reactants were conducted in urine and resulting specimens analyzed for the presence of chlorazanil. While no chlorazanil was found in drug formulations, the urine samples of 2 out of 4 proguanil users returned findings for chlorazanil at low ng/mL levels, similar to the adverse analytical findings in the doping control samples. Further, in the presence of formaldehyde, formic acid and related esters, 4-chlorophenyl-biguanide was found to produce chlorazanil in human urine, suggesting that the detection of the obsolete diuretic

  7. Potentiation of antimalarial drug action by chlorpheniramine against multidrug-resistant Plasmodium falciparum in vitro.

    PubMed

    Nakornchai, Sunan; Konthiang, Phattanapong

    2006-09-01

    Chlorpheniramine, a histamine H1 receptor antagonist, was assayed for in vitro antimalarial activity against multidrug-resistant Plasmodium falciparum K1 strain and chloroquine-resistant P. falciparum T9/94 clone, by measuring the 3H-hypoxanthine incorporation. Chlorphenirame inhibited P. falciparum K1 and T9/94 growth with IC50 values of 136.0+/-40.2 microM and 102.0+/-22.6 microM respectively. A combination of antimalarial drug and chlorpheniramine was tested against resistant P. falciparum in vitro. Isobologram analysis showed that chlorpheniramine exerts marked synergistic action on chloroquine against P. falciparum K1 and T9/94. Chlorpheniramine also potentiated antimalarial action of mefloquine, quinine or pyronaridine against both of the resistant strains of P. falciparum. However, chlorpheniramine antagonism with artesunate was obtained in both P. falciparum K1 and T9/94. The results in this study indicate that antihistaminic drugs may be promising candidates for potentiating antimalarial drug action against drug resistant malarial parasites.

  8. Serine Proteases of Malaria Parasite Plasmodium falciparum: Potential as Antimalarial Drug Targets

    PubMed Central

    2014-01-01

    Malaria is a major global parasitic disease and a cause of enormous mortality and morbidity. Widespread drug resistance against currently available antimalarials warrants the identification of novel drug targets and development of new drugs. Malarial proteases are a group of molecules that serve as potential drug targets because of their essentiality for parasite life cycle stages and feasibility of designing specific inhibitors against them. Proteases belonging to various mechanistic classes are found in P. falciparum, of which serine proteases are of particular interest due to their involvement in parasite-specific processes of egress and invasion. In P. falciparum, a number of serine proteases belonging to chymotrypsin, subtilisin, and rhomboid clans are found. This review focuses on the potential of P. falciparum serine proteases as antimalarial drug targets. PMID:24799897

  9. Amphiphilic dendritic derivatives as nanocarriers for the targeted delivery of antimalarial drugs.

    PubMed

    Movellan, Julie; Urbán, Patricia; Moles, Ernest; de la Fuente, Jesús M; Sierra, Teresa; Serrano, José Luis; Fernàndez-Busquets, Xavier

    2014-09-01

    It can be foreseen that in a future scenario of malaria eradication, a varied armamentarium will be required, including strategies for the targeted administration of antimalarial compounds. The development of nanovectors capable of encapsulating drugs and of delivering them to Plasmodium-infected cells with high specificity and efficacy and at an affordable cost is of particular interest. With this objective, dendritic derivatives based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Pluronic(®) polymers have been herein explored. Four different dendritic derivatives have been tested for their capacity to encapsulate the antimalarial drugs chloroquine (CQ) and primaquine (PQ), their specific targeting to Plasmodium-infected red blood cells (pRBCs), and their antimalarial activity in vitro against the human pathogen Plasmodium falciparum and in vivo against the rodent malaria species Plasmodium yoelii. The results obtained have allowed the identification of two dendritic derivatives exhibiting specific targeting to pRBCs vs. non-infected RBCs, which reduce the in vitro IC50 of CQ and PQ by ca. 3- and 4-fold down to 4.0 nm and 1.1 μm, respectively. This work on the application of dendritic derivatives to antimalarial targeted drug delivery opens the way for the use of this new type of chemicals in future malaria eradication programs.

  10. Irrational use of antimalarial drugs in rural areas of eastern Pakistan: a random field study

    PubMed Central

    2012-01-01

    Background Prescription of antimalarial drugs in the absence of malarial disease is a common practice in countries where malaria is endemic. However, unwarranted use of such drugs can cause side effects in some people and is a financial drain on local economies. In this study, we surveyed the prevalence of malaria parasites in humans, and the prevalence of the malaria transmitting mosquito vectors in the study area. We also investigated the use of antimalarial drugs in the local people. We focused on randomly selected rural areas of eastern Pakistan where no malaria cases had been reported since May 2004. Methods Mass blood surveys, active case detection, passive case detection, and vector density surveys were carried out in selected areas of Sargodha district from September 2008 to August 2009. Data pertaining to the quantities and types of antimalarial drugs used in these areas were collected from health centers, pharmacies, and the district CDC program of the Health Department of the Government of the Punjab. Results Seven hundred and forty four blood samples were examined, resulting in a Blood Examination Rate (BER) of 3.18; microscopic analysis of blood smears showed that none of the samples were positive for malaria parasites. Investigation of the mosquito vector density in 43 living rooms (bedrooms or rooms used for sleeping), 23 stores, and 32 animal sheds, revealed no vectors capable of transmitting malaria in these locations. In contrast, the density of Culex mosquitoes was high. Substantial consumption of a variety of antimalarial tablets, syrups, capsules and injections costing around 1000 US$, was documented for the region. Conclusion Use of antimalarial drugs in the absence of malarial infection or the vectors that transmit the disease was common in the study area. Continuous use of such drugs, not only in Pakistan, but in other parts of the world, may lead to drug-induced side effects amongst users. Better training of health care professionals is

  11. Metabolic Dysregulation Induced in Plasmodium falciparum by Dihydroartemisinin and Other Front-Line Antimalarial Drugs.

    PubMed

    Cobbold, Simon A; Chua, Hwa H; Nijagal, Brunda; Creek, Darren J; Ralph, Stuart A; McConville, Malcolm J

    2016-01-15

    Detailed information on the mode of action of antimalarial drugs can be used to improve existing drugs, identify new drug targets, and understand the basis of drug resistance. In this study we describe the use of a time-resolved, mass spectrometry (MS)-based metabolite profiling approach to map the metabolic perturbations induced by a panel of clinical antimalarial drugs and inhibitors on Plasmodium falciparum asexual blood stages. Drug-induced changes in metabolite levels in P. falciparum-infected erythrocytes were monitored over time using gas chromatography-MS and liquid chromatography-MS and changes in specific metabolic fluxes confirmed by nonstationary [(13)C]-glucose labeling. Dihydroartemisinin (DHA) was found to disrupt hemoglobin catabolism within 1 hour of exposure, resulting in a transient decrease in hemoglobin-derived peptides. Unexpectedly, it also disrupted pyrimidine biosynthesis, resulting in increased [(13)C]-glucose flux toward malate production, potentially explaining the susceptibility of P. falciparum to DHA during early blood-stage development. Unique metabolic signatures were also found for atovaquone, chloroquine, proguanil, cycloguanil and methylene blue. We also show that this approach can be used to identify the mode of action of novel antimalarials, such as the compound Torin 2, which inhibits hemoglobin catabolism. PMID:26150544

  12. Lead Clinical and Preclinical Antimalarial Drugs Can Significantly Reduce Sporozoite Transmission to Vertebrate Populations

    PubMed Central

    Upton, L. M.; Brock, P. M.; Churcher, T. S.; Ghani, A. C.; Gething, P. W.; Delves, M. J.; Sala, K. A.; Leroy, D.; Sinden, R. E.

    2014-01-01

    To achieve malarial elimination, we must employ interventions that reduce the exposure of human populations to infectious mosquitoes. To this end, numerous antimalarial drugs are under assessment in a variety of transmission-blocking assays which fail to measure the single crucial criteria of a successful intervention, namely impact on case incidence within a vertebrate population (reduction in reproductive number/effect size). Consequently, any reduction in new infections due to drug treatment (and how this may be influenced by differing transmission settings) is not currently examined, limiting the translation of any findings. We describe the use of a laboratory population model to assess how individual antimalarial drugs can impact the number of secondary Plasmodium berghei infections over a cycle of transmission. We examine the impact of multiple clinical and preclinical drugs on both insect and vertebrate populations at multiple transmission settings. Both primaquine (>6 mg/kg of body weight) and NITD609 (8.1 mg/kg) have significant impacts across multiple transmission settings, but artemether and lumefantrine (57 and 11.8 mg/kg), OZ439 (6.5 mg/kg), and primaquine (<1.25 mg/kg) demonstrated potent efficacy only at lower-transmission settings. While directly demonstrating the impact of antimalarial drug treatment on vertebrate populations, we additionally calculate effect size for each treatment, allowing for head-to-head comparison of the potential impact of individual drugs within epidemiologically relevant settings, supporting their usage within elimination campaigns. PMID:25385107

  13. Validation of ELISA for Quantitation of Artemisinin-Based Antimalarial Drugs

    PubMed Central

    Wang, Min; Cui, Yongliang; Zhou, Guofa; Yan, Guiyun; Cui, Liwang; Wang, Baomin

    2013-01-01

    The circulation of counterfeit or substandard artemisinins (ARTs) in malaria-endemic areas poses a serious threat to the long-term use of these drugs. Here, we validated an indirect competitive enzyme-linked immunosorbent assay (icELISA) for quantification of ARTs and found that 50% of inhibitory concentrations of dihydroartemisinin, artemether, and artesunate were 8.1, 207.0, and 4.7 ng/mL, respectively. We compared the icELISA with high-performance liquid chromatography (HPLC) for quantifying ART and its derivatives in 22 convenience samples of commercial antimalarial drugs. Paired t tests showed a borderline significant difference between the two methods (mean = 0.03, 95% confidence interval [CI] 0.00–0.07, P = 0.074) and the icELISA results were more variable than those of the HPLC analysis (P < 0.001), suggesting that further improvement is needed to enhance the performance of the icELISA. Our results showed that the icELISA has the potential to be improved for quality assurance of ARTs at the point of care in endemic settings. PMID:24080636

  14. Mechanisms of hematin crystallization and inhibition by the antimalarial drug chloroquine.

    PubMed

    Olafson, Katy N; Ketchum, Megan A; Rimer, Jeffrey D; Vekilov, Peter G

    2015-04-21

    Hematin crystallization is the primary mechanism of heme detoxification in malaria parasites and the target of the quinoline class of antimalarials. Despite numerous studies of malaria pathophysiology, fundamental questions regarding hematin growth and inhibition remain. Among them are the identity of the crystallization medium in vivo, aqueous or organic; the mechanism of crystallization, classical or nonclassical; and whether quinoline antimalarials inhibit crystallization by sequestering hematin in the solution, or by blocking surface sites crucial for growth. Here we use time-resolved in situ atomic force microscopy (AFM) and show that the lipid subphase in the parasite may be a preferred growth medium. We provide, to our knowledge, the first evidence of the molecular mechanisms of hematin crystallization and inhibition by chloroquine, a common quinoline antimalarial drug. AFM observations demonstrate that crystallization strictly follows a classical mechanism wherein new crystal layers are generated by 2D nucleation and grow by the attachment of solute molecules. We identify four classes of surface sites available for binding of potential drugs and propose respective mechanisms of drug action. Further studies reveal that chloroquine inhibits hematin crystallization by binding to molecularly flat {100} surfaces. A 2-μM concentration of chloroquine fully arrests layer generation and step advancement, which is ∼10(4)× less than hematin's physiological concentration. Our results suggest that adsorption at specific growth sites may be a general mode of hemozoin growth inhibition for the quinoline antimalarials. Because the atomic structures of the identified sites are known, this insight could advance the future design and/or optimization of new antimalarials. PMID:25831526

  15. Mechanisms of hematin crystallization and inhibition by the antimalarial drug chloroquine.

    PubMed

    Olafson, Katy N; Ketchum, Megan A; Rimer, Jeffrey D; Vekilov, Peter G

    2015-04-21

    Hematin crystallization is the primary mechanism of heme detoxification in malaria parasites and the target of the quinoline class of antimalarials. Despite numerous studies of malaria pathophysiology, fundamental questions regarding hematin growth and inhibition remain. Among them are the identity of the crystallization medium in vivo, aqueous or organic; the mechanism of crystallization, classical or nonclassical; and whether quinoline antimalarials inhibit crystallization by sequestering hematin in the solution, or by blocking surface sites crucial for growth. Here we use time-resolved in situ atomic force microscopy (AFM) and show that the lipid subphase in the parasite may be a preferred growth medium. We provide, to our knowledge, the first evidence of the molecular mechanisms of hematin crystallization and inhibition by chloroquine, a common quinoline antimalarial drug. AFM observations demonstrate that crystallization strictly follows a classical mechanism wherein new crystal layers are generated by 2D nucleation and grow by the attachment of solute molecules. We identify four classes of surface sites available for binding of potential drugs and propose respective mechanisms of drug action. Further studies reveal that chloroquine inhibits hematin crystallization by binding to molecularly flat {100} surfaces. A 2-μM concentration of chloroquine fully arrests layer generation and step advancement, which is ∼10(4)× less than hematin's physiological concentration. Our results suggest that adsorption at specific growth sites may be a general mode of hemozoin growth inhibition for the quinoline antimalarials. Because the atomic structures of the identified sites are known, this insight could advance the future design and/or optimization of new antimalarials.

  16. Impact of prepackaging antimalarial drugs on cost to patients and compliance with treatment.

    PubMed Central

    Yeboah-Antwi, K.; Gyapong, J. O.; Asare, I. K.; Barnish, G.; Evans, D. B.; Adjei, S.

    2001-01-01

    OBJECTIVE: To examine the extent to which district health teams could reduce the burden of malaria, a continuing major cause of mortality and morbidity, in a situation where severe resource constraints existed and integrated care was provided. METHODS: Antimalarial drugs were prepackaged into unit doses in an attempt to improve compliance with full courses of chemotherapy. FINDINGS: Compliance improved by approximately 20% in both adults and children. There were 50% reductions in cost to patients, waiting time at dispensaries and drug wastage at facilities. The intervention, which tended to improve both case and drug management at facilities, was well accepted by health staff and did not involve them in additional working time. CONCLUSION: The prepackaging of antimalarials at the district level offers the prospect of improved compliance and a reduction in the spread of resistance. PMID:11417034

  17. Interspecies Allometric Scaling of Antimalarial Drugs and Potential Application to Pediatric Dosing

    PubMed Central

    Senarathna, S. M. D. K. Ganga

    2014-01-01

    Pharmacopeial recommendations for administration of antimalarial drugs are the same weight-based (mg/kg of body weight) doses for children and adults. However, linear calculations are known to underestimate pediatric doses; therefore, interspecies allometric scaling data may have a role in predicting doses in children. We investigated the allometric scaling relationships of antimalarial drugs using data from pharmacokinetic studies in mammalian species. Simple allometry (Y = a × Wb) was utilized and compared to maximum life span potential (MLP) correction. All drugs showed a strong correlation with clearance (CL) in healthy controls. Insufficient data from malaria-infected species other than humans were available for allometric scaling. The allometric exponents (b) for CL of artesunate, dihydroartemisinin (from intravenous artesunate), artemether, artemisinin, clindamycin, piperaquine, mefloquine, and quinine were 0.71, 0.85, 0.66, 0.83, 0.62, 0.96, 0.52, and 0.40, respectively. Clearance was significantly lower in malaria infection than in healthy (adult) humans for quinine (0.07 versus 0.17 liter/h/kg; P = 0.0002) and dihydroartemisinin (0.81 versus 1.11 liters/h/kg; P = 0.04; power = 0.6). Interpolation of simple allometry provided better estimates of CL for children than MLP correction, which generally underestimated CL values. Pediatric dose calculations based on simple allometric exponents were 10 to 70% higher than pharmacopeial (mg/kg) recommendations. Interpolation of interspecies allometric scaling could provide better estimates than linear scaling of adult to pediatric doses of antimalarial drugs; however, the use of a fixed exponent for CL was not supported in the present study. The variability in allometric exponents for antimalarial drugs also has implications for scaling of fixed-dose combinations. PMID:25092696

  18. Antimalarial natural products: a review

    PubMed Central

    Mojab, Faraz

    2012-01-01

    Objective: Malaria is an infectious disease commonplace in tropical countries. For many years, major antimalarial drugs consisted of natural products, but since 1930s these drugs have been largely replaced with a series of synthetic drugs. This article tries to briefly indicate that some plants which previously were used to treat malaria, as a result of deficiencies of synthetic drugs, have revived into useful products once more. It also attempts to describe some tests which can be used to evaluate plant extracts for antimalarial activity. Materials and Methods: By referring to some recent literatures, data were collected about plants used for the treatment of malaria, evaluation of plant extracts for antimalarial activity, modes of action of natural antimalarial agents, and recent research on antimalarial plants in Iran and other countries. Results and Conclusion: There is an urgent need for the development of new treatments for malaria. Many countries have a vast precedence in the use of medicinal plants and the required knowledge spans many centuries. Although malaria is controlled in Iran, some researchers tend to study malaria and related subjects. In vitro biological tests for the detection of antimalarial activities in plant extracts are currently available. It is vital that the efficacy and safety of traditional medicines be validated and their active constituents be identified in order to establish reliable quality control measures. PMID:25050231

  19. CRIMALDDI: a prioritized research agenda to expedite the discovery of new anti-malarial drugs

    PubMed Central

    2013-01-01

    The CRIMALDDI Consortium has been a three-year project funded by the EU Framework Seven Programme. It aimed to develop a prioritized set of recommendations to speed up anti-malarial drug discovery research and contribute to the setting of the global research agenda. It has attempted to align thinking on the high priority issues and then to develop action plans and strategies to address these issues. Through a series of facilitated and interactive workshops, it has concluded that these priorities can be grouped under five key themes: attacking artemisinin resistance; creating and sharing community resources; delivering enabling technologies; exploiting high throughput screening hits quickly; and, identifying novel targets. Recommendations have been prioritized into one of four levels: quick wins; removing key roadblocks to future progress; speeding-up drug discovery; and, nice to have (but not essential). Use of this prioritization allows efforts and resources to be focused on the lines of work that will contribute most to expediting anti-malarial drug discovery. Estimates of the time and finances required to implement the recommendations have also been made, along with indications of when recommendations within each theme will make an impact. All of this has been collected into an indicative roadmap that, it is hoped, will guide decisions about the direction and focus of European anti-malarial drug discovery research and contribute to the setting of the global research agenda. PMID:24191947

  20. Molecular surveillance of antimalarial drug resistance related genes in Plasmodium falciparum isolates from Eritrea.

    PubMed

    Menegon, Michela; Nurahmed, Abduselam M; Talha, Albadawi A; Nour, Bakri Y M; Severini, Carlo

    2016-05-01

    The introduction of artemisinin-based combination therapy has led to extraordinary results in malaria control, however the recent emergence of partial resistance to artemisinin therapy in Southeast Asia jeopardizes these successes. This study aimed at investigating resistance to the antimalarial drugs by evaluating the polymorphisms in the PfK13, Pfcrt and Pfmdr1 genes in Plasmodium falciparum isolates obtained from patients in Eritrea.

  1. Mind the gaps - the epidemiology of poor-quality anti-malarials in the malarious world - analysis of the WorldWide Antimalarial Resistance Network database

    PubMed Central

    2014-01-01

    Background Poor quality medicines threaten the lives of millions of patients and are alarmingly common in many parts of the world. Nevertheless, the global extent of the problem remains unknown. Accurate estimates of the epidemiology of poor quality medicines are sparse and are influenced by sampling methodology and diverse chemical analysis techniques. In order to understand the existing data, the Antimalarial Quality Scientific Group at WWARN built a comprehensive, open-access, global database and linked Antimalarial Quality Surveyor, an online visualization tool. Analysis of the database is described here, the limitations of the studies and data reported, and their public health implications discussed. Methods The database collates customized summaries of 251 published anti-malarial quality reports in English, French and Spanish by time and location since 1946. It also includes information on assays to determine quality, sampling and medicine regulation. Results No publicly available reports for 60.6% (63) of the 104 malaria-endemic countries were found. Out of 9,348 anti-malarials sampled, 30.1% (2,813) failed chemical/packaging quality tests with 39.3% classified as falsified, 2.3% as substandard and 58.3% as poor quality without evidence available to categorize them as either substandard or falsified. Only 32.3% of the reports explicitly described their definitions of medicine quality and just 9.1% (855) of the samples collected in 4.6% (six) surveys were conducted using random sampling techniques. Packaging analysis was only described in 21.5% of publications and up to twenty wrong active ingredients were found in falsified anti-malarials. Conclusions There are severe neglected problems with anti-malarial quality but there are important caveats to accurately estimate the prevalence and distribution of poor quality anti-malarials. The lack of reports in many malaria-endemic areas, inadequate sampling techniques and inadequate chemical analytical methods and

  2. Linking Murine and Human Plasmodium falciparum Challenge Models in a Translational Path for Antimalarial Drug Development

    PubMed Central

    McCarthy, James S.; Marquart, Louise; Sekuloski, Silvana; Trenholme, Katharine; Elliott, Suzanne; Griffin, Paul; Rockett, Rebecca; O'Rourke, Peter; Sloots, Theo; Angulo-Barturen, Iñigo; Ferrer, Santiago; Jiménez-Díaz, María Belén; Martínez, María-Santos; Duparc, Stephan; Leroy, Didier; Wells, Timothy N. C.; Baker, Mark

    2016-01-01

    Effective progression of candidate antimalarials is dependent on optimal dosing in clinical studies, which is determined by a sound understanding of pharmacokinetics and pharmacodynamics (PK/PD). Recently, two important translational models for antimalarials have been developed: the NOD/SCID/IL2Rγ−/− (NSG) model, whereby mice are engrafted with noninfected and Plasmodium falciparum-infected human erythrocytes, and the induced blood-stage malaria (IBSM) model in human volunteers. The antimalarial mefloquine was used to directly measure the PK/PD in both models, which were compared to previously published trial data for malaria patients. The clinical part was a single-center, controlled study using a blood-stage Plasmodium falciparum challenge inoculum in volunteers to characterize the effectiveness of mefloquine against early malaria. The study was conducted in three cohorts (n = 8 each) using different doses of mefloquine. The characteristic delay in onset of action of about 24 h was seen in both NSG and IBSM systems. In vivo 50% inhibitory concentrations (IC50s) were estimated at 2.0 μg/ml and 1.8 μg/ml in the NSG and IBSM models, respectively, aligning with 1.8 μg/ml reported previously for patients. In the IBSM model, the parasite reduction ratios were 157 and 195 for the 10- and 15-mg/kg doses, within the range of previously reported clinical data for patients but significantly lower than observed in the mouse model. Linking mouse and human challenge models to clinical trial data can accelerate the accrual of critical data on antimalarial drug activity. Such data can guide large clinical trials required for development of urgently needed novel antimalarial combinations. (This trial was registered at the Australian New Zealand Clinical Trials Registry [http://anzctr.org.au] under registration number ACTRN12612000323820.) PMID:27044554

  3. Linking Murine and Human Plasmodium falciparum Challenge Models in a Translational Path for Antimalarial Drug Development.

    PubMed

    McCarthy, James S; Marquart, Louise; Sekuloski, Silvana; Trenholme, Katharine; Elliott, Suzanne; Griffin, Paul; Rockett, Rebecca; O'Rourke, Peter; Sloots, Theo; Angulo-Barturen, Iñigo; Ferrer, Santiago; Jiménez-Díaz, María Belén; Martínez, María-Santos; Hooft van Huijsduijnen, Rob; Duparc, Stephan; Leroy, Didier; Wells, Timothy N C; Baker, Mark; Möhrle, Jörg J

    2016-06-01

    Effective progression of candidate antimalarials is dependent on optimal dosing in clinical studies, which is determined by a sound understanding of pharmacokinetics and pharmacodynamics (PK/PD). Recently, two important translational models for antimalarials have been developed: the NOD/SCID/IL2Rγ(-/-) (NSG) model, whereby mice are engrafted with noninfected and Plasmodium falciparum-infected human erythrocytes, and the induced blood-stage malaria (IBSM) model in human volunteers. The antimalarial mefloquine was used to directly measure the PK/PD in both models, which were compared to previously published trial data for malaria patients. The clinical part was a single-center, controlled study using a blood-stage Plasmodium falciparum challenge inoculum in volunteers to characterize the effectiveness of mefloquine against early malaria. The study was conducted in three cohorts (n = 8 each) using different doses of mefloquine. The characteristic delay in onset of action of about 24 h was seen in both NSG and IBSM systems. In vivo 50% inhibitory concentrations (IC50s) were estimated at 2.0 μg/ml and 1.8 μg/ml in the NSG and IBSM models, respectively, aligning with 1.8 μg/ml reported previously for patients. In the IBSM model, the parasite reduction ratios were 157 and 195 for the 10- and 15-mg/kg doses, within the range of previously reported clinical data for patients but significantly lower than observed in the mouse model. Linking mouse and human challenge models to clinical trial data can accelerate the accrual of critical data on antimalarial drug activity. Such data can guide large clinical trials required for development of urgently needed novel antimalarial combinations. (This trial was registered at the Australian New Zealand Clinical Trials Registry [http://anzctr.org.au] under registration number ACTRN12612000323820.). PMID:27044554

  4. Altering Antimalarial Drug Regimens May Dramatically Enhance and Restore Drug Effectiveness.

    PubMed

    Kay, Katherine; Hodel, Eva Maria; Hastings, Ian M

    2015-10-01

    There is considerable concern that malaria parasites are starting to evolve resistance to the current generation of antimalarial drugs, the artemisinin-based combination therapies (ACTs). We use pharmacological modeling to investigate changes in ACT effectiveness likely to occur if current regimens are extended from 3 to 5 days or, alternatively, given twice daily over 3 days. We show that the pharmacology of artemisinins allows both regimen changes to substantially increase the artemisinin killing rate. Malaria patients rarely contain more than 10(12) parasites, while the standard dosing regimens allow approximately 1 in 10(10) parasites to survive artemisinin treatment. Parasite survival falls dramatically, to around 1 in 10(17) parasites if the dose is extended or split; theoretically, this increase in drug killing appears to be more than sufficient to restore failing ACT efficacy. One of the most widely used dosing regimens, artemether-lumefantrine, already successfully employs a twice-daily dosing regimen, and we argue that twice-daily dosing should be incorporated into all ACT regimen design considerations as a simple and effective way of ensuring the continued long-term effectiveness of ACTs. PMID:26239993

  5. Altering Antimalarial Drug Regimens May Dramatically Enhance and Restore Drug Effectiveness

    PubMed Central

    Hastings, Ian M.

    2015-01-01

    There is considerable concern that malaria parasites are starting to evolve resistance to the current generation of antimalarial drugs, the artemisinin-based combination therapies (ACTs). We use pharmacological modeling to investigate changes in ACT effectiveness likely to occur if current regimens are extended from 3 to 5 days or, alternatively, given twice daily over 3 days. We show that the pharmacology of artemisinins allows both regimen changes to substantially increase the artemisinin killing rate. Malaria patients rarely contain more than 1012 parasites, while the standard dosing regimens allow approximately 1 in 1010 parasites to survive artemisinin treatment. Parasite survival falls dramatically, to around 1 in 1017 parasites if the dose is extended or split; theoretically, this increase in drug killing appears to be more than sufficient to restore failing ACT efficacy. One of the most widely used dosing regimens, artemether-lumefantrine, already successfully employs a twice-daily dosing regimen, and we argue that twice-daily dosing should be incorporated into all ACT regimen design considerations as a simple and effective way of ensuring the continued long-term effectiveness of ACTs. PMID:26239993

  6. Chemical and genetic validation of thiamine utilization as an antimalarial drug target.

    PubMed

    Chan, Xie Wah Audrey; Wrenger, Carsten; Stahl, Katharina; Bergmann, Bärbel; Winterberg, Markus; Müller, Ingrid B; Saliba, Kevin J

    2013-01-01

    Thiamine is metabolized into an essential cofactor for several enzymes. Here we show that oxythiamine, a thiamine analog, inhibits proliferation of the malaria parasite Plasmodium falciparum in vitro via a thiamine-related pathway and significantly reduces parasite growth in a mouse malaria model. Overexpression of thiamine pyrophosphokinase (the enzyme that converts thiamine into its active form, thiamine pyrophosphate) hypersensitizes parasites to oxythiamine by up to 1,700-fold, consistent with oxythiamine being a substrate for thiamine pyrophosphokinase and its conversion into an antimetabolite. We show that parasites overexpressing the thiamine pyrophosphate-dependent enzymes oxoglutarate dehydrogenase and pyruvate dehydrogenase are up to 15-fold more resistant to oxythiamine, consistent with the antimetabolite inactivating thiamine pyrophosphate-dependent enzymes. Our studies therefore validate thiamine utilization as an antimalarial drug target and demonstrate that a single antimalarial can simultaneously target several enzymes located within distinct organelles.

  7. How Patients Take Malaria Treatment: A Systematic Review of the Literature on Adherence to Antimalarial Drugs

    PubMed Central

    Bruxvoort, Katia; Goodman, Catherine; Kachur, S. Patrick; Schellenberg, David

    2014-01-01

    Background High levels of patient adherence to antimalarial treatment are important in ensuring drug effectiveness. To achieve this goal, it is important to understand levels of patient adherence, and the range of study designs and methodological challenges involved in measuring adherence and interpreting results. Since antimalarial adherence was reviewed in 2004, there has been a major expansion in the use of artemisinin-based combination therapies (ACTs) in the public sector, as well as initiatives to make them more widely accessible through community health workers and private retailers. These changes and the large number of recent adherence studies raise the need for an updated review on this topic. Objective We conducted a systematic review of studies reporting quantitative results on patient adherence to antimalarials obtained for treatment. Results The 55 studies identified reported extensive variation in patient adherence to antimalarials, with many studies reporting very high adherence (90–100%) and others finding adherence of less than 50%. We identified five overarching approaches to assessing adherence based on the definition of adherence and the methods used to measure it. Overall, there was no clear pattern in adherence results by approach. However, adherence tended to be higher among studies where informed consent was collected at the time of obtaining the drug, where patient consultations were directly observed by research staff, and where a diagnostic test was obtained. Conclusion Variations in reported adherence may reflect factors related to patient characteristics and the nature of their consultation with the provider, as well as methodological variations such as interaction between the research team and patients before and during the treatment. Future studies can benefit from an awareness of the impact of study procedures on adherence outcomes, and the identification of improved measurement methods less dependent on self-report. PMID:24465418

  8. Antimalarial Drug Discovery: Approaches and Progress towards New Medicines

    PubMed Central

    Flannery, Erika L.; Chatterjee, Arnab K.; Winzeler, Elizabeth A.

    2014-01-01

    Malaria elimination has recently been reinstated as a global health priority but current therapies seem to be insufficient for the task. Elimination efforts require new drug classes that alleviate symptoms, prevent transmission and provide a radical cure. To develop these next generation medicines, public-private partnerships are funding innovative approaches to identify compounds that target multiple parasite species at multiple stages of the parasite lifecycle. Here, we review the cell-, chemistry- and target-based approaches used to discover new drug candidates that are currently in clinical trials or undergoing preclinical testing. PMID:24217412

  9. Study of the efficacy of antimalarial drugs delivered inside targeted immunoliposomal nanovectors

    NASA Astrophysics Data System (ADS)

    Urbán, Patricia; Estelrich, Joan; Adeva, Alberto; Cortés, Alfred; Fernàndez-Busquets, Xavier

    2011-12-01

    Paul Ehrlich's dream of a 'magic bullet' that would specifically destroy invading microbes is now a major aspect of clinical medicine. However, a century later, the implementation of this medical holy grail continues being a challenge in three main fronts: identifying the right molecular or cellular targets for a particular disease, having a drug that is effective against it, and finding a strategy for the efficient delivery of sufficient amounts of the drug in an active state exclusively to the selected targets. In a previous work, we engineered an immunoliposomal nanovector for the targeted delivery of its contents exclusively to Plasmodium falciparum-infected red blood cells [pRBCs]. In preliminary assays, the antimalarial drug chloroquine showed improved efficacy when delivered inside immunoliposomes targeted with the pRBC-specific monoclonal antibody BM1234. Because difficulties in determining the exact concentration of the drug due to its low amounts prevented an accurate estimation of the nanovector performance, here, we have developed an HPLC-based method for the precise determination of the concentrations in the liposomal preparations of chloroquine and of a second antimalarial drug, fosmidomycin. The results obtained indicate that immunoliposome encapsulation of chloroquine and fosmidomycin improves by tenfold the efficacy of antimalarial drugs. The targeting antibody used binds preferentially to pRBCs containing late maturation stages of the parasite. In accordance with this observation, the best performing immunoliposomes are those added to Plasmodium cultures having a larger number of late form-containing pRBCs. An average of five antibody molecules per liposome significantly improves in cell cultures the performance of immunoliposomes over non-functionalized liposomes as drug delivery vessels. Increasing the number of antibodies on the liposome surface correspondingly increases performance, with a reduction of 50% parasitemia achieved with

  10. The Interactions of P-Glycoprotein with Antimalarial Drugs, Including Substrate Affinity, Inhibition and Regulation.

    PubMed

    Senarathna, S M D K Ganga; Page-Sharp, Madhu; Crowe, Andrew

    2016-01-01

    The combination of passive drug permeability, affinity for uptake and efflux transporters as well as gastrointestinal metabolism defines net drug absorption. Efflux mechanisms are often overlooked when examining the absorption phase of drug bioavailability. Knowing the affinity of antimalarials for efflux transporters such as P-glycoprotein (P-gp) may assist in the determination of drug absorption and pharmacokinetic drug interactions during oral absorption in drug combination therapies. Concurrent administration of P-gp inhibitors and P-gp substrate drugs may also result in alterations in the bioavailability of some antimalarials. In-vitro Caco-2 cell monolayers were used here as a model for potential drug absorption related problems and P-gp mediated transport of drugs. Artemisone had the highest permeability at around 50 x 10(-6) cm/sec, followed by amodiaquine around 20 x 10(-6) cm/sec; both mefloquine and artesunate were around 10 x 10(-6) cm/sec. Methylene blue was between 2 and 6 x 10(-6) cm/sec depending on the direction of transport. This 3 fold difference was able to be halved by use of P-gp inhibition. MRP inhibition also assisted the consolidation of the methylene blue transport. Mefloquine was shown to be a P-gp inhibitor affecting our P-gp substrate, Rhodamine 123, although none of the other drugs impacted upon rhodamine123 transport rates. In conclusion, mefloquine is a P-gp inhibitor and methylene blue is a partial substrate; methylene blue may have increased absorption if co-administered with such P-gp inhibitors. An upregulation of P-gp was observed when artemisone and dihydroartemisinin were co-incubated with mefloquine and amodiaquine. PMID:27045516

  11. The Interactions of P-Glycoprotein with Antimalarial Drugs, Including Substrate Affinity, Inhibition and Regulation.

    PubMed

    Senarathna, S M D K Ganga; Page-Sharp, Madhu; Crowe, Andrew

    2016-01-01

    The combination of passive drug permeability, affinity for uptake and efflux transporters as well as gastrointestinal metabolism defines net drug absorption. Efflux mechanisms are often overlooked when examining the absorption phase of drug bioavailability. Knowing the affinity of antimalarials for efflux transporters such as P-glycoprotein (P-gp) may assist in the determination of drug absorption and pharmacokinetic drug interactions during oral absorption in drug combination therapies. Concurrent administration of P-gp inhibitors and P-gp substrate drugs may also result in alterations in the bioavailability of some antimalarials. In-vitro Caco-2 cell monolayers were used here as a model for potential drug absorption related problems and P-gp mediated transport of drugs. Artemisone had the highest permeability at around 50 x 10(-6) cm/sec, followed by amodiaquine around 20 x 10(-6) cm/sec; both mefloquine and artesunate were around 10 x 10(-6) cm/sec. Methylene blue was between 2 and 6 x 10(-6) cm/sec depending on the direction of transport. This 3 fold difference was able to be halved by use of P-gp inhibition. MRP inhibition also assisted the consolidation of the methylene blue transport. Mefloquine was shown to be a P-gp inhibitor affecting our P-gp substrate, Rhodamine 123, although none of the other drugs impacted upon rhodamine123 transport rates. In conclusion, mefloquine is a P-gp inhibitor and methylene blue is a partial substrate; methylene blue may have increased absorption if co-administered with such P-gp inhibitors. An upregulation of P-gp was observed when artemisone and dihydroartemisinin were co-incubated with mefloquine and amodiaquine.

  12. The Interactions of P-Glycoprotein with Antimalarial Drugs, Including Substrate Affinity, Inhibition and Regulation

    PubMed Central

    Senarathna, S M D K Ganga; Page-Sharp, Madhu; Crowe, Andrew

    2016-01-01

    The combination of passive drug permeability, affinity for uptake and efflux transporters as well as gastrointestinal metabolism defines net drug absorption. Efflux mechanisms are often overlooked when examining the absorption phase of drug bioavailability. Knowing the affinity of antimalarials for efflux transporters such as P-glycoprotein (P-gp) may assist in the determination of drug absorption and pharmacokinetic drug interactions during oral absorption in drug combination therapies. Concurrent administration of P-gp inhibitors and P-gp substrate drugs may also result in alterations in the bioavailability of some antimalarials. In-vitro Caco-2 cell monolayers were used here as a model for potential drug absorption related problems and P-gp mediated transport of drugs. Artemisone had the highest permeability at around 50 x 10−6 cm/sec, followed by amodiaquine around 20 x 10−6 cm/sec; both mefloquine and artesunate were around 10 x 10−6 cm/sec. Methylene blue was between 2 and 6 x 10−6 cm/sec depending on the direction of transport. This 3 fold difference was able to be halved by use of P-gp inhibition. MRP inhibition also assisted the consolidation of the methylene blue transport. Mefloquine was shown to be a P-gp inhibitor affecting our P-gp substrate, Rhodamine 123, although none of the other drugs impacted upon rhodamine123 transport rates. In conclusion, mefloquine is a P-gp inhibitor and methylene blue is a partial substrate; methylene blue may have increased absorption if co-administered with such P-gp inhibitors. An upregulation of P-gp was observed when artemisone and dihydroartemisinin were co-incubated with mefloquine and amodiaquine. PMID:27045516

  13. Why Hospital Pharmacists Have Failed to Manage Antimalarial Drugs Stock-Outs in Pakistan? A Qualitative Insight

    PubMed Central

    Hassali, Mohamed Azmi Ahmad; Shafie, Asrul Akmal; Hussain, Azhar

    2013-01-01

    Purpose. This study aimed to explore the perceptions of hospital pharmacists towards drug management and reasons underlying stock-outs of antimalarial drugs in Pakistan. Methods. A qualitative study was designed to explore the perceptions of hospital pharmacists regarding drug management and irrational use of antimalarial drugs in two major cities of Pakistan, namely, Islamabad (national capital) and Rawalpindi (twin city). Semistructured interviews were conducted with 16 hospital pharmacists using indepth interview guides at a place and time convenient for the respondents. Interviews, which were audiotaped and transcribed verbatim, were evaluated by thematic content analysis and by other authors' analysis. Results. Most of the respondents were of the view that financial constraints, inappropriate drug management, and inadequate funding were the factors contributing toward the problem of antimalarial drug stock-outs in healthcare facilities of Pakistan. The pharmacists anticipated that prescribing by nonproprietary names, training of health professionals, accepted role of hospital pharmacist in drug management, implementation of essential drug list and standard treatment guidelines for malaria in the healthcare system can minimize the problem of drug stock outs in healthcare system of Pakistan. Conclusion. The current study showed that all the respondents in the two cities agreed that hospital pharmacist has failed to play an effective role in efficient management of anti-malarial drugs stock-outs. PMID:24223321

  14. Policy options for deploying anti-malarial drugs in endemic countries: a population genetics approach

    PubMed Central

    2012-01-01

    Background Anti-malarial drugs are constantly exposed to the threat of evolving drug resistance so good stewardship of existing therapy is an essential component of public health policy. However, the widespread availability of numerous different drugs through informal providers could undermine official drug deployment policies. A policy of multiple first-line therapy (MFT) is compared with the conventional policy of sequential drug deployment, i.e., where one drug is used until resistance evolves and then replaced by the next drug in the sequence. Methods Population genetic models of drug resistance are used to make the comparison; this methodology explicitly tracks the genetics of drug resistance (including, importantly, recombination in the sexual stage, intrahost dynamics, and direction of linkage disequilibrium). Results A policy of MFT outlasts sequential application providing drug usages are low to moderate, and appears not to drive widespread multi-drug resistance. Inadequate dosing is an even more potent driver of drug resistance than the MFT/sequential policy decision. Conclusions The provision of MFT as a deliberate policy can be encouraged provided overall treatment rates are low or moderate (less than around half of malaria infections are treated) and the ad hoc provision of MFT through the private sector may be tolerated. This must be fully supported by education to ensure people take adequate doses of each of the drugs. PMID:23244624

  15. Antimalarial drug resistance: a review of the biology and strategies to delay emergence and spread

    PubMed Central

    Klein, E.Y.

    2013-01-01

    The emergence of resistance to former first-line antimalarial drugs has been an unmitigated disaster. In recent years, artemisinin class drugs have become standard and they are considered an essential tool for helping to eradicate the disease. However, their ability to reduce morbidity and mortality and to slow transmission requires the maintenance of effectiveness. Recently, an artemisinin delayed-clearance phenotype was described. This is believed to be the precursor to resistance and threatens local elimination and global eradication plans. Understanding how resistance emerges and spreads is important for developing strategies to contain its spread. Resistance is the result of two processes: (i) drug selection of resistant parasites; and (ii) the spread of resistance. In this review, we examine the factors that lead to both drug selection and the spread of resistance. We then examine strategies for controlling the spread of resistance, pointing out the complexities and deficiencies in predicting how resistance will spread. PMID:23394809

  16. Interaction of quinoline antimalarial drugs with ferriprotoporphyrin IX, a solid state spectroscopy study.

    PubMed

    Asghari-Khiavi, Mehdi; Vongsvivut, Jitraporn; Perepichka, Inna; Mechler, Adam; Wood, Bayden R; McNaughton, Don; Bohle, D Scott

    2011-12-01

    To investigate the nature of binding of quinoline antimalarial drugs to heme and to extract experimental evidence for this binding, the interaction of ferriprotoporphyrin IX (FP) with chloroquine and quinacrine (both of which have a similar side chain) and quinoline methanol antimalarials quinine and mefloquine has been studied using IR and NIR-Raman spectroscopy in the solid state. Attenuated total reflectance infrared spectroscopic data clearly show that heme in chloroquine-FP complex is not μ-oxo dimeric indicating that the hypothesis that chloroquine binds to FP μ-oxo dimer with a stoichiometry of 1 chloroquine:2 μ-oxo dimers is not valid in the solid state. Moreover, the first vibrational spectroscopy evidence is presented for the formation of hydrogen bonding between a propionate group of heme and the tertiary amino nitrogen of chloroquine and quinacrine. Raman spectroscopy data does not provide any evidence to support the formation of a similar salt bridge in the complexes of FP with quinine and mefloquine; however, it suggests that the interaction of these drugs with FP happens through coordination of the Fe(III) center of the porphyrin to the 9-hydroxy group of the drug.

  17. Chemogenomic profiling of Plasmodium falciparum as a tool to aid antimalarial drug discovery.

    PubMed

    Pradhan, Anupam; Siwo, Geoffrey H; Singh, Naresh; Martens, Brian; Balu, Bharath; Button-Simons, Katrina A; Tan, Asako; Zhang, Min; Udenze, Kenneth O; Jiang, Rays H Y; Ferdig, Michael T; Adams, John H; Kyle, Dennis E

    2015-01-01

    The spread of Plasmodium falciparum multidrug resistance highlights the urgency to discover new targets and chemical scaffolds. Unfortunately, lack of experimentally validated functional information about most P. falciparum genes remains a strategic hurdle. Chemogenomic profiling is an established tool for classification of drugs with similar mechanisms of action by comparing drug fitness profiles in a collection of mutants. Inferences of drug mechanisms of action and targets can be obtained by associations between shifts in drug fitness and specific genetic changes in the mutants. In this screen, P. falciparum, piggyBac single insertion mutants were profiled for altered responses to antimalarial drugs and metabolic inhibitors to create chemogenomic profiles. Drugs targeting the same pathway shared similar response profiles and multiple pairwise correlations of the chemogenomic profiles revealed novel insights into drugs' mechanisms of action. A mutant of the artemisinin resistance candidate gene - "K13-propeller" gene (PF3D7_1343700) exhibited increased susceptibility to artemisinin drugs and identified a cluster of 7 mutants based on similar enhanced responses to the drugs tested. Our approach of chemogenomic profiling reveals artemisinin functional activity, linked by the unexpected drug-gene relationships of these mutants, to signal transduction and cell cycle regulation pathways.

  18. Anti-malarial Drugs Primaquine and Chloroquine Have Different Sensitization Effects with Anti-mitotic Drugs in Resistant Cancer Cells.

    PubMed

    Choi, Ae-Ran; Kim, Ju-Hwa; Woo, Yeon Hwa; Kim, Hyung Sik; Yoon, Sungpil

    2016-04-01

    The purpose of this study was to identify conditions that would increase the sensitivity of drug-resistant cancer cells. Previously, two anti-malarial drugs, chloroquine (CHL) and primaquine (PRI), showed different sensitization effects for vinblastine (VIB)-resistant cancer cells. Herein, we tested co-treatment of cells with CHL or PRI and other microtubule-targeting cancer drugs, namely, vinorelbine (VIO), paclitaxel (PAC), docetaxel (DOC), vincristine (VIC), or halaven (HAL). We found that PRI sensitized P-glycoprotein (P-gp)-overexpressing drug-resistant KBV20C cells to all six anti-mitotic drugs to a similar extent. CHL had a similar sensitization effect only for co-treatment with PAC, DOC, VIC, and HAL, while the sensitization effect was less marked for co-treatment with VIB or VIO. FACS analysis and western blot analysis revealed that G2arrest and apoptosis showed only a slight increase on co-treatment with VIB or VIO and CHL. We also found that phospho-histone H3 and pRb were markedly increased only by PRI-VIB co-treatment, but not by CHL-VIB co-treatment. This suggests that reduction in the expression of these proteins correlates with decreased G2arrest in CHL-VIB co-treatment. We further compared the effect of another anti-malarial drug, mefloquine (MEF), in combination with the six anti-mitotic drugs. We found that MEF and PRI had similar sensitization effects in co-treatment with these anti-mitotic drugs. PRI and MEF had generally similar sensitization effects in co-treatment with anti-mitotic drugs, suggesting that they do not have any preferred anti-mitotic drug partner in co-treatment. This indicates that only CHL shows specificity in co-treatment with anti-mitotic drugs in resistant cancer cells. Our results may contribute to the choice of anti-mitotic drugs to be used in co-treatment of resistant cancer cells with the anti-malarial drugs, CHL, PRI, and MEF. PMID:27069141

  19. Chemogenomic profiling of Plasmodium falciparum as a tool to aid antimalarial drug discovery

    PubMed Central

    Pradhan, Anupam; Siwo, Geoffrey H.; Singh, Naresh; Martens, Brian; Balu, Bharath; Button-Simons, Katrina A.; Tan, Asako; Zhang, Min; Udenze, Kenneth O.; Jiang, Rays H.Y.; Ferdig, Michael T.; Adams, John H.; Kyle, Dennis E.

    2015-01-01

    The spread of Plasmodium falciparum multidrug resistance highlights the urgency to discover new targets and chemical scaffolds. Unfortunately, lack of experimentally validated functional information about most P. falciparum genes remains a strategic hurdle. Chemogenomic profiling is an established tool for classification of drugs with similar mechanisms of action by comparing drug fitness profiles in a collection of mutants. Inferences of drug mechanisms of action and targets can be obtained by associations between shifts in drug fitness and specific genetic changes in the mutants. In this screen, P. falciparum, piggyBac single insertion mutants were profiled for altered responses to antimalarial drugs and metabolic inhibitors to create chemogenomic profiles. Drugs targeting the same pathway shared similar response profiles and multiple pairwise correlations of the chemogenomic profiles revealed novel insights into drugs’ mechanisms of action. A mutant of the artemisinin resistance candidate gene - “K13-propeller” gene (PF3D7_1343700) exhibited increased susceptibility to artemisinin drugs and identified a cluster of 7 mutants based on similar enhanced responses to the drugs tested. Our approach of chemogenomic profiling reveals artemisinin functional activity, linked by the unexpected drug-gene relationships of these mutants, to signal transduction and cell cycle regulation pathways. PMID:26541648

  20. Understanding the biology of the Plasmodium falciparum apicoplast; an excellent target for antimalarial drug development.

    PubMed

    Chakraborty, Arnish

    2016-08-01

    Malaria is a life-threatening tropical disease, caused by the intracellular parasite Plasmodium falciparum. The World Health Organization counts malaria as one of the top ten causes of worldwide death. The unavailability of a successful malaria vaccine and the ever-increasing instances of drug resistance in the malaria parasite demand the discovery of new targets within P. falciparum for the development of next generation antimalarials. Fortunately, all apicomplexan parasites, including P. falciparum harbor a relict, non-photosynthetic plastid known as the apicoplast. The apicoplast is a semi-autonomous organelle within P. falciparum containing a 35kb circular genome. Despite a genome of its own, majority of the apicoplast proteins are encoded by the parasite nucleus and imported into the apicoplast. The organelle has been shown to be essential to P. falciparum survival and the loss the apicoplast manifests as a 'delayed death' response in the parasite. The apicoplast has evolved out of cyanobacteria in a complex, two step endosymbiotic event. As a result the architecture and the gene expression machinery of the apicoplast is quite bacteria-like and is susceptible to a wide range of antibiotics such as fosmidomycin, tetracycline, azithromycin, clindamycin and triclosan. The biosynthetic pathways for isoprenoids, fatty acids and heme operate within the malaria apicoplast, making the organelle an excellent target for drug development. The review focuses on the evolution, biology and the essentiality of the apicoplast within the malaria parasite and discusses some of the recent achievements towards the design and discovery of apicoplast targeted antimalarial compounds.

  1. Discovery and Characterization of ACT-451840: an Antimalarial Drug with a Novel Mechanism of Action.

    PubMed

    Boss, Christoph; Aissaoui, Hamed; Amaral, Nathalie; Bauer, Aude; Bazire, Stephanie; Binkert, Christoph; Brun, Reto; Bürki, Cédric; Ciana, Claire-Lise; Corminboeuf, Olivier; Delahaye, Stephane; Dollinger, Claire; Fischli, Christoph; Fischli, Walter; Flock, Alexandre; Frantz, Marie-Céline; Girault, Malory; Grisostomi, Corinna; Friedli, Astrid; Heidmann, Bibia; Hinder, Claire; Jacob, Gael; Le Bihan, Amelie; Malrieu, Sophie; Mamzed, Saskia; Merot, Aurelien; Meyer, Solange; Peixoto, Sabrina; Petit, Nolwenn; Siegrist, Romain; Trollux, Julien; Weller, Thomas; Wittlin, Sergio

    2016-09-20

    More than 40 % of the world's population is at risk of being infected with malaria. Most malaria cases occur in the countries of sub-Saharan Africa, Central and South America, and Asia. Resistance to standard therapy, including artemisinin combinations, is increasing. There is an urgent need for novel antimalarials with new mechanisms of action. In a phenotypic screen, we identified a series of phenylalanine-based compounds that exhibit antimalarial activity via a new and yet unknown mechanism of action. Our optimization efforts culminated in the selection of ACT-451840 [(S,E)-N-(4-(4-acetylpiperazin-1-yl)benzyl)-3-(4-(tert-butyl)phenyl)-N-(1-(4-(4-cyanobenzyl)piperazin-1-yl)-1-oxo-3-phenylpropan-2-yl)acrylamide] for clinical development. Herein we describe our optimization efforts from the screening hit to the potential drug candidate with respect to antiparasitic activity, drug metabolism and pharmacokinetics (DMPK) properties, and in vivo pharmacological efficacy.

  2. 2D Inorganic-Antimalarial Drug-Polymer Hybrid with pH-Responsive Solubility.

    PubMed

    Kim, Ji-Yeong; Yang, Jae-Hun; Lee, Ji-Hee; Choi, Goeun; Park, Dae-Hwan; Jo, Mi-Rea; Choi, Soo-Jin; Choy, Jin-Ho

    2015-10-01

    Artesunic acid (ASH), an antimalarial drug, has low oral bioavailability due to its low aqueous solubility. To overcome this problem, artesunate (AS) was intercalated into zinc basic salt (ZBS) via co-precipitation. AS was immobilized with a tilted double layer arrangement, which was also confirmed by XRD and 1-D electron density mapping. In order to decrease the release rate of AS under gastrointestinal conditions and to simultaneously increase the release rate of AS under intestinal conditions, ZBS-AS was coated with EUDRAGIT L100 (ZBS-AS-L100). Finally, we performed an in-vivo pharmacokinetic study to compare the oral bioavailability of AS of ZBS-AS-L100 with that of ASH. Surprisingly, it was found that the former is 5.5 times greater than the latter due to an enhanced solubility of AS thanks to the ternary hybridization with ZBS and EUDRAGIT L100. Therefore, the present ZBS-AS-L100 system has a great potential as a novel antimalarial drug formulation with pH selectivity and enhanced bioavailability.

  3. Quality of Artemisinin-Containing Antimalarials in Tanzania's Private Sector--Results from a Nationally Representative Outlet Survey.

    PubMed

    2015-06-01

    Ensuring that artemisinin-containing antimalarials (ACAs) are of good quality is a key component of effective malaria treatment. There are concerns that a high proportion of ACAs are falsified or substandard, though estimates are rarely based on representative data. During a nationally representative survey in Tanzania, ACAs were purchased from private retail drug outlets, and the active pharmaceutical ingredient (API) was measured. All 1,737 ACAs contained the labeled artemisinin derivative, with 4.1% being outside the 85-115% artemisinin API range defined as acceptable quality. World Health Organization (WHO) prequalified drugs had 0.1 times the odds of being poor quality compared with non-prequalified ACAs for the artemisinin component. When partner components of combination therapies were also considered, 12.1% were outside the acceptable API range, and WHO prequalified ACAs had 0.04 times the odds of being poor quality. Although the prevalence of poor quality ACAs was lower than reported elsewhere, the minority of samples found to be substandard is a cause for concern. Improvements in quality could be achieved by increasing the predominance of WHO prequalified products in the market. Continued monitoring of quality standards is essential.

  4. Quality of Artemisinin-Containing Antimalarials in Tanzania's Private Sector—Results from a Nationally Representative Outlet Survey

    PubMed Central

    2015-01-01

    Ensuring that artemisinin-containing antimalarials (ACAs) are of good quality is a key component of effective malaria treatment. There are concerns that a high proportion of ACAs are falsified or substandard, though estimates are rarely based on representative data. During a nationally representative survey in Tanzania, ACAs were purchased from private retail drug outlets, and the active pharmaceutical ingredient (API) was measured. All 1,737 ACAs contained the labeled artemisinin derivative, with 4.1% being outside the 85–115% artemisinin API range defined as acceptable quality. World Health Organization (WHO) prequalified drugs had 0.1 times the odds of being poor quality compared with non-prequalified ACAs for the artemisinin component. When partner components of combination therapies were also considered, 12.1% were outside the acceptable API range, and WHO prequalified ACAs had 0.04 times the odds of being poor quality. Although the prevalence of poor quality ACAs was lower than reported elsewhere, the minority of samples found to be substandard is a cause for concern. Improvements in quality could be achieved by increasing the predominance of WHO prequalified products in the market. Continued monitoring of quality standards is essential. PMID:25897065

  5. CRIMALDDI: a co-ordinated, rational, and integrated effort to set logical priorities in anti-malarial drug discovery initiatives

    PubMed Central

    2010-01-01

    Despite increasing efforts and support for anti-malarial drug R&D, globally anti-malarial drug discovery and development remains largely uncoordinated and fragmented. The current window of opportunity for large scale funding of R&D into malaria is likely to narrow in the coming decade due to a contraction in available resources caused by the current economic difficulties and new priorities (e.g. climate change). It is, therefore, essential that stakeholders are given well-articulated action plans and priorities to guide judgments on where resources can be best targeted. The CRIMALDDI Consortium (a European Union funded initiative) has been set up to develop, through a process of stakeholder and expert consultations, such priorities and recommendations to address them. It is hoped that the recommendations will help to guide the priorities of the European anti-malarial research as well as the wider global discovery agenda in the coming decade. PMID:20626844

  6. Molecular Farming in Artemisia annua, a Promising Approach to Improve Anti-malarial Drug Production

    PubMed Central

    Pulice, Giuseppe; Pelaz, Soraya; Matías-Hernández, Luis

    2016-01-01

    Malaria is a parasite infection affecting millions of people worldwide. Even though progress has been made in prevention and treatment of the disease; an estimated 214 million cases of malaria occurred in 2015, resulting in 438,000 estimated deaths; most of them occurring in Africa among children under the age of five. This article aims to review the epidemiology, future risk factors and current treatments of malaria, with particular focus on the promising potential of molecular farming that uses metabolic engineering in plants as an effective anti-malarial solution. Malaria represents an example of how a health problem may, on one hand, influence the proper development of a country, due to its burden of the disease. On the other hand, it constitutes an opportunity for lucrative business of diverse stakeholders. In contrast, plant biofarming is proposed here as a sustainable, promising, alternative for the production, not only of natural herbal repellents for malaria prevention but also for the production of sustainable anti-malarial drugs, like artemisinin (AN), used for primary parasite infection treatments. AN, a sesquiterpene lactone, is a natural anti-malarial compound that can be found in Artemisia annua. However, the low concentration of AN in the plant makes this molecule relatively expensive and difficult to produce in order to meet the current worldwide demand of Artemisinin Combination Therapies (ACTs), especially for economically disadvantaged people in developing countries. The biosynthetic pathway of AN, a process that takes place only in glandular secretory trichomes of A. annua, is relatively well elucidated. Significant efforts have been made using plant genetic engineering to increase production of this compound. These include diverse genetic manipulation approaches, such as studies on diverse transcription factors which have been shown to regulate the AN genetic pathway and other biological processes. Results look promising; however, further

  7. Molecular Farming in Artemisia annua, a Promising Approach to Improve Anti-malarial Drug Production.

    PubMed

    Pulice, Giuseppe; Pelaz, Soraya; Matías-Hernández, Luis

    2016-01-01

    Malaria is a parasite infection affecting millions of people worldwide. Even though progress has been made in prevention and treatment of the disease; an estimated 214 million cases of malaria occurred in 2015, resulting in 438,000 estimated deaths; most of them occurring in Africa among children under the age of five. This article aims to review the epidemiology, future risk factors and current treatments of malaria, with particular focus on the promising potential of molecular farming that uses metabolic engineering in plants as an effective anti-malarial solution. Malaria represents an example of how a health problem may, on one hand, influence the proper development of a country, due to its burden of the disease. On the other hand, it constitutes an opportunity for lucrative business of diverse stakeholders. In contrast, plant biofarming is proposed here as a sustainable, promising, alternative for the production, not only of natural herbal repellents for malaria prevention but also for the production of sustainable anti-malarial drugs, like artemisinin (AN), used for primary parasite infection treatments. AN, a sesquiterpene lactone, is a natural anti-malarial compound that can be found in Artemisia annua. However, the low concentration of AN in the plant makes this molecule relatively expensive and difficult to produce in order to meet the current worldwide demand of Artemisinin Combination Therapies (ACTs), especially for economically disadvantaged people in developing countries. The biosynthetic pathway of AN, a process that takes place only in glandular secretory trichomes of A. annua, is relatively well elucidated. Significant efforts have been made using plant genetic engineering to increase production of this compound. These include diverse genetic manipulation approaches, such as studies on diverse transcription factors which have been shown to regulate the AN genetic pathway and other biological processes. Results look promising; however, further

  8. Assessment of the Worldwide Antimalarial Resistance Network Standardized Procedure for In Vitro Malaria Drug Sensitivity Testing Using SYBR Green Assay for Field Samples with Various Initial Parasitemia Levels

    PubMed Central

    Cheruiyot, Agnes C.; Auschwitz, Jennifer M.; Lee, Patricia J.; Yeda, Redemptah A.; Okello, Charles O.; Leed, Susan E.; Talwar, Mayank; Murthy, Tushar; Gaona, Heather W.; Hickman, Mark R.; Akala, Hoseah M.; Kamau, Edwin

    2016-01-01

    The malaria SYBR green assay, which is used to profile in vitro drug susceptibility of Plasmodium falciparum, is a reliable drug screening and surveillance tool. Malaria field surveillance efforts provide isolates with various low levels of parasitemia. To be advantageous, malaria drug sensitivity assays should perform reproducibly among various starting parasitemia levels rather than at one fixed initial value. We examined the SYBR green assay standardized procedure developed by the Worldwide Antimalarial Resistance Network (WWARN) for its sensitivity and ability to accurately determine the drug concentration that inhibits parasite growth by 50% (IC50) in samples with a range of initial parasitemia levels. The initial sensitivity determination of the WWARN procedure yielded a detection limit of 0.019% parasitemia. P. falciparum laboratory strains and field isolates with various levels of initial parasitemia were then subjected to a range of doses of common antimalarials. The IC50s were comparable for laboratory strains with between 0.0375% and 0.6% parasitemia and for field isolates with between 0.075% and 0.6% parasitemia for all drugs tested. Furthermore, assay quality (Z′) analysis indicated that the WWARN procedure displays high robustness, allowing for drug testing of malaria field samples within the derived range of initial parasitemia. The use of the WWARN procedure should allow for the inclusion of more malaria field samples in malaria drug sensitivity screens that would have otherwise been excluded due to low initial parasitemia levels. PMID:26856829

  9. Holographic analysis on deformation and restoration of malaria-infected red blood cells by antimalarial drug

    NASA Astrophysics Data System (ADS)

    Byeon, Hyeokjun; Ha, Young-Ran; Lee, Sang Joon

    2015-11-01

    Malaria parasites induce morphological, biochemical, and mechanical changes in red blood cells (RBCs). Mechanical variations are closely related to the deformability of individual RBCs. The deformation of various RBCs, including healthy and malaria-infected RBCs (iRBCs), can be directly observed through quantitative phase imaging (QPI). The effects of chloroquine treatment on the mechanical property variation of iRBCs were investigated using time-resolved holographic QPI of single live cells on a millisecond time scale. The deformabilities of healthy RBCs, iRBCs, and drug-treated iRBCs were compared, and the effect of chloroquine on iRBC restoration was experimentally examined. The present results are beneficial to elucidate the dynamic characteristics of iRBCs and the effect of the antimalarial drug on iRBCs.

  10. Validation of N-myristoyltransferase as an antimalarial drug target using an integrated chemical biology approach

    NASA Astrophysics Data System (ADS)

    Wright, Megan H.; Clough, Barbara; Rackham, Mark D.; Rangachari, Kaveri; Brannigan, James A.; Grainger, Munira; Moss, David K.; Bottrill, Andrew R.; Heal, William P.; Broncel, Malgorzata; Serwa, Remigiusz A.; Brady, Declan; Mann, David J.; Leatherbarrow, Robin J.; Tewari, Rita; Wilkinson, Anthony J.; Holder, Anthony A.; Tate, Edward W.

    2014-02-01

    Malaria is an infectious disease caused by parasites of the genus Plasmodium, which leads to approximately one million deaths per annum worldwide. Chemical validation of new antimalarial targets is urgently required in view of rising resistance to current drugs. One such putative target is the enzyme N-myristoyltransferase, which catalyses the attachment of the fatty acid myristate to protein substrates (N-myristoylation). Here, we report an integrated chemical biology approach to explore protein myristoylation in the major human parasite P. falciparum, combining chemical proteomic tools for identification of the myristoylated and glycosylphosphatidylinositol-anchored proteome with selective small-molecule N-myristoyltransferase inhibitors. We demonstrate that N-myristoyltransferase is an essential and chemically tractable target in malaria parasites both in vitro and in vivo, and show that selective inhibition of N-myristoylation leads to catastrophic and irreversible failure to assemble the inner membrane complex, a critical subcellular organelle in the parasite life cycle. Our studies provide the basis for the development of new antimalarials targeting N-myristoyltransferase.

  11. Quality of anti-malarials collected in the private and informal sectors in Guyana and Suriname

    PubMed Central

    2012-01-01

    Background Despite a significant reduction in the number of malaria cases in Guyana and Suriname, this disease remains a major problem in the interior of both countries, especially in areas with gold mining and logging operations, where malaria is endemic. National malaria control programmes in these countries provide treatment to patients with medicines that are procured and distributed through regulated processes in the public sector. However, availability to medicines in licensed facilities (private sector) and unlicensed facilities (informal sector) is common, posing the risk of access to and use of non-recommended treatments and/or poor quality products. Methods To assess the quality of circulating anti-malarial medicines, samples were purchased in the private and informal sectors of Guyana and Suriname in 2009. The sampling sites were selected based on epidemiological data and/or distance from health facilities. Samples were analysed for identity, content, dissolution or disintegration, impurities, and uniformity of dosage units or weight variation according to manufacturer, pharmacopeial, or other validated method. Results Quality issues were observed in 45 of 77 (58%) anti-malarial medicines sampled in Guyana of which 30 failed visual & physical inspection and 18 failed quality control tests. The proportion of monotherapy and ACT medicines failing quality control tests was 43% (13/30) and 11% (5/47) respectively. A higher proportion of medicines sampled from the private sector 34% (11/32) failed quality control tests versus 16% (7/45) in the informal sector. In Suriname, 58 medicines were sampled, of which 50 (86%) were Artecom®, the fixed-dose combination of piperaquine-dihydroartemisinin-trimethoprim co-blistered with a primaquine phosphate tablet. All Artecom samples were found to lack a label claim for primaquine, thus failing visual and physical inspection. Conclusions The findings of the studies in both countries point to significant problems with

  12. Assessment of the Worldwide Antimalarial Resistance Network Standardized Procedure for In Vitro Malaria Drug Sensitivity Testing Using SYBR Green Assay for Field Samples with Various Initial Parasitemia Levels.

    PubMed

    Cheruiyot, Agnes C; Auschwitz, Jennifer M; Lee, Patricia J; Yeda, Redemptah A; Okello, Charles O; Leed, Susan E; Talwar, Mayank; Murthy, Tushar; Gaona, Heather W; Hickman, Mark R; Akala, Hoseah M; Kamau, Edwin; Johnson, Jacob D

    2016-04-01

    The malaria SYBR green assay, which is used to profilein vitrodrug susceptibility ofPlasmodium falciparum, is a reliable drug screening and surveillance tool. Malaria field surveillance efforts provide isolates with various low levels of parasitemia. To be advantageous, malaria drug sensitivity assays should perform reproducibly among various starting parasitemia levels rather than at one fixed initial value. We examined the SYBR green assay standardized procedure developed by the Worldwide Antimalarial Resistance Network (WWARN) for its sensitivity and ability to accurately determine the drug concentration that inhibits parasite growth by 50% (IC50) in samples with a range of initial parasitemia levels. The initial sensitivity determination of the WWARN procedure yielded a detection limit of 0.019% parasitemia.P. falciparumlaboratory strains and field isolates with various levels of initial parasitemia were then subjected to a range of doses of common antimalarials. The IC50s were comparable for laboratory strains with between 0.0375% and 0.6% parasitemia and for field isolates with between 0.075% and 0.6% parasitemia for all drugs tested. Furthermore, assay quality (Z') analysis indicated that the WWARN procedure displays high robustness, allowing for drug testing of malaria field samples within the derived range of initial parasitemia. The use of the WWARN procedure should allow for the inclusion of more malaria field samples in malaria drug sensitivity screens that would have otherwise been excluded due to low initial parasitemia levels.

  13. Understanding the biology of the Plasmodium falciparum apicoplast; an excellent target for antimalarial drug development.

    PubMed

    Chakraborty, Arnish

    2016-08-01

    Malaria is a life-threatening tropical disease, caused by the intracellular parasite Plasmodium falciparum. The World Health Organization counts malaria as one of the top ten causes of worldwide death. The unavailability of a successful malaria vaccine and the ever-increasing instances of drug resistance in the malaria parasite demand the discovery of new targets within P. falciparum for the development of next generation antimalarials. Fortunately, all apicomplexan parasites, including P. falciparum harbor a relict, non-photosynthetic plastid known as the apicoplast. The apicoplast is a semi-autonomous organelle within P. falciparum containing a 35kb circular genome. Despite a genome of its own, majority of the apicoplast proteins are encoded by the parasite nucleus and imported into the apicoplast. The organelle has been shown to be essential to P. falciparum survival and the loss the apicoplast manifests as a 'delayed death' response in the parasite. The apicoplast has evolved out of cyanobacteria in a complex, two step endosymbiotic event. As a result the architecture and the gene expression machinery of the apicoplast is quite bacteria-like and is susceptible to a wide range of antibiotics such as fosmidomycin, tetracycline, azithromycin, clindamycin and triclosan. The biosynthetic pathways for isoprenoids, fatty acids and heme operate within the malaria apicoplast, making the organelle an excellent target for drug development. The review focuses on the evolution, biology and the essentiality of the apicoplast within the malaria parasite and discusses some of the recent achievements towards the design and discovery of apicoplast targeted antimalarial compounds. PMID:27381078

  14. Stability of the Antimalarial Drug Dihydroartemisinin under Physiologically Relevant Conditions: Implications for Clinical Treatment and Pharmacokinetic and In Vitro Assays

    PubMed Central

    Parapini, Silvia; Olliaro, Piero; Navaratnam, Visweswaran; Taramelli, Donatella

    2015-01-01

    Artemisinins are peroxidic antimalarial drugs known to be very potent but highly chemically unstable; they degrade in the presence of ferrous iron, Fe(II)-heme, or biological reductants. Less documented is how this translates into chemical stability and antimalarial activity across a range of conditions applying to in vitro testing and clinical situations. Dihydroartemisinin (DHA) is studied here because it is an antimalarial drug on its own and the main metabolite of other artemisinins. The behaviors of DHA in phosphate-buffered saline, plasma, or erythrocyte lysate at different temperatures and pH ranges were examined. The antimalarial activity of the residual drug was evaluated using the chemosensitivity assay on Plasmodium falciparum, and the extent of decomposition of DHA was established through use of high-performance liquid chromatography with electrochemical detection analysis. The role of the Fe(II)-heme was investigated by blocking its reactivity using carbon monoxide (CO). A significant reduction in the antimalarial activity of DHA was seen after incubation in plasma and to a lesser extent in erythrocyte lysate. Activity was reduced by half after 3 h and almost completely abolished after 24 h. Serum-enriched media also affected DHA activity. Effects were temperature and pH dependent and paralleled the increased rate of decomposition of DHA from pH 7 upwards and in plasma. These results suggest that particular care should be taken in conducting and interpreting in vitro studies, prone as their results are to experimental and drug storage conditions. Disorders such as fever, hemolysis, or acidosis associated with malaria severity may contribute to artemisinin instability and reduce their clinical efficacy. PMID:25918150

  15. Mass administration of the antimalarial drug mefloquine to Guantánamo detainees: a critical analysis.

    PubMed

    Nevin, Remington L

    2012-10-01

    Recently, evidence has emerged from an unusual form of mass drug administration practised among detainees held at US Naval Station Guantánamo Bay, Cuba ('Guantánamo'), ostensibly as a public health measure. Mefloquine, an antimalarial drug originally developed by the US military, whose use is associated with a range of severe neuropsychiatric adverse effects, was administered at treatment doses to detainees immediately upon their arrival at Guantánamo, prior to laboratory testing for malaria and irrespective of symptoms of disease. In this analysis, the history of mefloquine's development is reviewed and the indications for its administration at treatment doses are discussed. The stated rationale for the use of mefloquine among Guantánamo detainees is then evaluated in the context of accepted forms of population-based malaria control. It is concluded that there was no plausible public health indication for the use of mefloquine at Guantánamo and that based on prevailing standards of care, the clinical indications for its use are decidedly unclear. This analysis suggests the troubling possibility that the use of mefloquine at Guantánamo may have been motivated in part by knowledge of the drug's adverse effects, and points to a critical need for further investigation to resolve unanswered questions regarding the drug's potentially inappropriate use. PMID:22882560

  16. Evaluation of the Quality of Artemisinin-Based Antimalarial Medicines Distributed in Ghana and Togo

    PubMed Central

    Agbonon, Amegnona; Konadu, Daniel Yeboah; Edoh, Mamadou; Gordon, Andrew; Gbeassor, Messanvi; Addae-Mensah, Ivan

    2014-01-01

    This study, conducted as part of our overall goal of regular pharmacovigilance of antimalarial medicines, reports on the quality of 132 artemisinin-based antimalarial medicines distributed in Ghana and Togo. Three methods were employed in the quality evaluation—basic (colorimetric) tests for establishing the identity of the requisite active pharmaceutical ingredients (APIs), semi-quantitative TLC assay for the identification and estimation of API content, and HPLC assay for a more accurate quantification of API content. From the basic tests, only one sample totally lacked API. The HPLC assay, however, showed that 83.7% of the ACTs and 57.9% of the artemisinin-based monotherapies failed to comply with international pharmacopoeia requirements due to insufficient API content. In most of the ACTs, the artemisinin component was usually the insufficient API. Generally, there was a good correlation between the HPLC and SQ-TLC assays. The overall failure rates for both locally manufactured (77.3%) and imported medicines (77.5%) were comparable. Similarly the unregistered medicines recorded a slightly higher overall failure rate (84.7%) than registered medicines (70.8%). Only two instances of possible cross-border exchange of medicines were observed and there was little difference between the medicine quality of collections from border towns and those from inland parts of both countries. PMID:25400975

  17. Combating poor-quality anti-malarial medicines: a call to action.

    PubMed

    Bassat, Quique; Tanner, Marcel; Guerin, Philippe J; Stricker, Kirstin; Hamed, Kamal

    2016-01-01

    The circulation of poor-quality medicines continues to undermine the fight against many life-threatening diseases. Anti-malarial medicines appear to have been particularly compromised and present a major public health threat in malaria-endemic countries, negatively affecting individuals and their communities. Concerted collaborative efforts are required from global, regional and national organizations, involving the public and private sectors, to address the problem. While many initiatives are underway, a number of unmet needs deserve urgent and increased multisector attention. At the global level, there is a need for an international public health legal framework or treaty on poor-quality medicines, with statutes suitable for integration into national laws. In addition, increased international efforts are required to strengthen the governance of global supply chains and enhance cooperation between national medicine regulation authorities and law enforcement bodies. Increased investment is needed in innovative technologies that will enable healthcare teams to detect poor-quality medicines at all levels of the supply chain. At the regional level, a number of initiatives would be beneficial-key areas are standardization, simplification, and reciprocal recognition of registration processes and development of quality control capacity in regional centres of excellence that are better aligned with public health needs; improved surveillance methods and creation of a framework for compulsory and transparent reporting of poor-quality medicines; additional support for national medicine regulation authorities and other national partner authorities; and an increase in support for regional laboratories to boost their capabilities in detecting poor-quality medicines. It is vital that all stakeholders involved in efforts against poor-quality anti-malarial medicines extend and strengthen their actions in these critical areas and thus effectively support global health development

  18. Salinomycin and Other Ionophores as a New Class of Antimalarial Drugs with Transmission-Blocking Activity

    PubMed Central

    D'Alessandro, Sarah; Corbett, Yolanda; Ilboudo, Denise P.; Misiano, Paola; Dahiya, Nisha; Abay, Solomon M.; Habluetzel, Annette; Grande, Romualdo; Gismondo, Maria R.; Dechering, Koen J.; Koolen, Karin M. J.; Sauerwein, Robert W.; Taramelli, Donatella; Parapini, Silvia

    2015-01-01

    The drug target profile proposed by the Medicines for Malaria Venture for a malaria elimination/eradication policy focuses on molecules active on both asexual and sexual stages of Plasmodium, thus with both curative and transmission-blocking activities. The aim of the present work was to investigate whether the class of monovalent ionophores, which includes drugs used in veterinary medicine and that were recently proposed as human anticancer agents, meets these requirements. The activity of salinomycin, monensin, and nigericin on Plasmodium falciparum asexual and sexual erythrocytic stages and on the development of the Plasmodium berghei and P. falciparum mosquito stages is reported here. Gametocytogenesis of the P. falciparum strain 3D7 was induced in vitro, and gametocytes at stage II and III or stage IV and V of development were treated for different lengths of time with the ionophores and their viability measured with the parasite lactate dehydrogenase (pLDH) assay. The monovalent ionophores efficiently killed both asexual parasites and gametocytes with a nanomolar 50% inhibitory concentration (IC50). Salinomycin showed a fast speed of kill compared to that of standard drugs, and the potency was higher on stage IV and V than on stage II and III gametocytes. The ionophores inhibited ookinete development and subsequent oocyst formation in the mosquito midgut, confirming their transmission-blocking activity. Potential toxicity due to hemolysis was excluded, since only infected and not normal erythrocytes were damaged by ionophores. Our data strongly support the downstream exploration of monovalent ionophores for repositioning as new antimalarial and transmission-blocking leads. PMID:26055362

  19. Hemin potentiates the anti-hepatitis C virus activity of the antimalarial drug artemisinin

    SciTech Connect

    Paeshuyse, Jan; Coelmont, Lotte; Vliegen, Inge; Hemel, Johan van; Vandenkerckhove, Jan; Peys, Eric; Sas, Benedikt; Clercq, Erik De; Neyts, Johan . E-mail: johan.neyts@rega.kuleuven.be

    2006-09-15

    We report that the antimalarial drug artemisinin inhibits hepatitis C virus (HCV) replicon replication in a dose-dependent manner in two replicon constructs at concentrations that have no effect on the proliferation of the exponentially growing host cells. The 50% effective concentration (EC{sub 5}) for inhibition of HCV subgenomic replicon replication in Huh 5-2 cells (luciferase assay) by artemisinin was 78 {+-} 21 {mu}M. Hemin, an iron donor, was recently reported to inhibit HCV replicon replication [mediated by inhibition of the viral polymerase (C. Fillebeen, A.M. Rivas-Estilla, M. Bisaillon, P. Ponka, M. Muckenthaler, M.W. Hentze, A.E. Koromilas, K. Pantopoulos, Iron inactivates the RNA polymerase NS5B and suppresses subgenomic replication of hepatitis C virus, J. Biol. Chem. 280 (2005) 9049-9057.)] at a concentration that had no adverse effect on the host cells. When combined, artemisinin and hemin resulted, over a broad concentration range, in a pronounced synergistic antiviral activity. Also at a concentration (2 {mu}M) that alone had no effect on HCV replication, hemin still potentiated the anti-HCV activity of artemisinin.

  20. Molecular markers of anti-malarial drug resistance in Lahj Governorate, Yemen: baseline data and implications

    PubMed Central

    2011-01-01

    Background This is an investigation of anti-malarial molecular markers coupled with a therapeutic efficacy test of chloroquine (CQ) against falciparum malaria in an area of unstable malaria in Lahj Governorate, Yemen. The study was aimed at assessment of therapeutic response to CQ and elucidation of baseline information on molecular markers for Plasmodium falciparum resistance against CQ and sulphadoxine/pyrimethamine (SP). Methods Between 2002 and 2003 the field test was conducted according to the standard WHO protocol to evaluate the therapeutic efficacy of CQ in 124 patients with falciparum malaria in an endemic area in Lahj Governorate in Yemen. Blood samples collected during this study were analysed for P. falciparum chloroquine resistance transporter gene (pfcrt)-76 polymorphisms, mutation pfcrt-S163R and the antifolate resistance-associated mutations dihydrofolate reductase (dhfr)-C59R and dihydropteroate synthase (dhps)-K540E. Direct DNA sequencing of the pfcrt gene from three representative field samples was carried out after DNA amplification of the 13 exons of the pfcrt gene. Results Treatment failure was detected in 61% of the 122 cases that completed the 14-day follow-up. The prevalence of mutant pfcrt T76 was 98% in 112 amplified pre-treatment samples. The presence of pfcrt T76 was poorly predictive of in vivo CQ resistance (PPV = 61.8%, 95% CI = 52.7-70.9). The prevalence of dhfr Arg-59 mutation in 99 amplified samples was 5%, while the dhps Glu-540 was not detected in any of 119 amplified samples. Sequencing the pfcrt gene confirmed that Yemeni CQ resistant P. falciparum carry the old world (Asian and African) CQ resistant haplotype CVIETSESI at positions 72,73,74,75,76,220,271, 326 and 371. Conclusion This is the first study to report baseline information on the characteristics and implications of anti-malarial drug resistance markers in Yemen. It is also the first report of the haplotype associated with CQR P. falciparum parasites from Yemen

  1. Benefits of a pharmacology antimalarial reference standard and proficiency testing program provided by the Worldwide Antimalarial Resistance Network (WWARN).

    PubMed

    Lourens, Chris; Lindegardh, Niklas; Barnes, Karen I; Guerin, Philippe J; Sibley, Carol H; White, Nicholas J; Tarning, Joel

    2014-07-01

    Comprehensive assessment of antimalarial drug resistance should include measurements of antimalarial blood or plasma concentrations in clinical trials and in individual assessments of treatment failure so that true resistance can be differentiated from inadequate drug exposure. Pharmacometric modeling is necessary to assess pharmacokinetic-pharmacodynamic relationships in different populations to optimize dosing. To accomplish both effectively and to allow comparison of data from different laboratories, it is essential that drug concentration measurement is accurate. Proficiency testing (PT) of laboratory procedures is necessary for verification of assay results. Within the Worldwide Antimalarial Resistance Network (WWARN), the goal of the quality assurance/quality control (QA/QC) program is to facilitate and sustain high-quality antimalarial assays. The QA/QC program consists of an international PT program for pharmacology laboratories and a reference material (RM) program for the provision of antimalarial drug standards, metabolites, and internal standards for laboratory use. The RM program currently distributes accurately weighed quantities of antimalarial drug standards, metabolites, and internal standards to 44 pharmacology, in vitro, and drug quality testing laboratories. The pharmacology PT program has sent samples to eight laboratories in four rounds of testing. WWARN technical experts have provided advice for correcting identified problems to improve performance of subsequent analysis and ultimately improved the quality of data. Many participants have demonstrated substantial improvements over subsequent rounds of PT. The WWARN QA/QC program has improved the quality and value of antimalarial drug measurement in laboratories globally. It is a model that has potential to be applied to strengthening laboratories more widely and improving the therapeutics of other infectious diseases.

  2. Benefits of a Pharmacology Antimalarial Reference Standard and Proficiency Testing Program Provided by the Worldwide Antimalarial Resistance Network (WWARN)

    PubMed Central

    Lourens, Chris; Lindegardh, Niklas; Barnes, Karen I.; Guerin, Philippe J.; Sibley, Carol H.; White, Nicholas J.

    2014-01-01

    Comprehensive assessment of antimalarial drug resistance should include measurements of antimalarial blood or plasma concentrations in clinical trials and in individual assessments of treatment failure so that true resistance can be differentiated from inadequate drug exposure. Pharmacometric modeling is necessary to assess pharmacokinetic-pharmacodynamic relationships in different populations to optimize dosing. To accomplish both effectively and to allow comparison of data from different laboratories, it is essential that drug concentration measurement is accurate. Proficiency testing (PT) of laboratory procedures is necessary for verification of assay results. Within the Worldwide Antimalarial Resistance Network (WWARN), the goal of the quality assurance/quality control (QA/QC) program is to facilitate and sustain high-quality antimalarial assays. The QA/QC program consists of an international PT program for pharmacology laboratories and a reference material (RM) program for the provision of antimalarial drug standards, metabolites, and internal standards for laboratory use. The RM program currently distributes accurately weighed quantities of antimalarial drug standards, metabolites, and internal standards to 44 pharmacology, in vitro, and drug quality testing laboratories. The pharmacology PT program has sent samples to eight laboratories in four rounds of testing. WWARN technical experts have provided advice for correcting identified problems to improve performance of subsequent analysis and ultimately improved the quality of data. Many participants have demonstrated substantial improvements over subsequent rounds of PT. The WWARN QA/QC program has improved the quality and value of antimalarial drug measurement in laboratories globally. It is a model that has potential to be applied to strengthening laboratories more widely and improving the therapeutics of other infectious diseases. PMID:24777099

  3. Cyclosporin A in Membrane Lipids Environment: Implications for Antimalarial Activity of the Drug--The Langmuir Monolayer Studies.

    PubMed

    Dynarowicz-Łątka, Patrycja; Wnętrzak, Anita; Makyła-Juzak, Katarzyna

    2015-12-01

    Cyclosporin A (CsA), a hydrophobic cyclic peptide produced by the fungus Tolypocladium inflatum, is well known for its high efficiency as an immunosuppressor for transplanted organs and anti-inflammatory properties; however, it is also active as antiparasitic (antimalarial) drug. Antimalarial mechanism of CsA action lacks a detailed understanding at molecular level. Due to a high lipophilicity of CsA, it is able to interact with lipids of cellular membrane; however, molecular targets of this drug are still unknown. To get a deeper insight into the mode of antimalarial activity of CsA, it is of utmost importance to examine its interactions with membrane components. To reach this goal, the Langmuir monolayer technique, which serves as a very useful, easy to handle and controllable model of biomembranes, has been employed. In this work, the interactions between CsA and main membrane lipids, i.e., cholesterol (Chol), 2-oleoyl-1-palmitoyl-3-phosphocholine (POPC), and sphingomyelin (SM), have been investigated. Attractive interactions are observed only for CsA mixtures with SM, while repulsive forces occur in systems containing remaining membrane lipids. Taking into consideration mutual interactions between membrane lipids (Chol-SM; Chol-POPC and SM-POPC), the behavior of CsA in model erythrocyte membrane of normal and infected cells has been analyzed. Our results prove strong affinity of CsA to SM in membrane environment. Since normal and parasitized erythrocytes differ significantly in the level of SM, this phospholipid may be considered as a molecular target for antimalarial activity of CsA.

  4. Pharmacoeconomics of Antimalarials in Private-for-Profit (PFP) Drug-Outlets in Gulu and Kitgum Towns, Northern Uganda

    PubMed Central

    Maghanga, Mshilla; Gerald, Obai; David, Musoke

    2015-01-01

    Background Clinically-diagnosed malaria is the leading cause of morbidity and mortality in Uganda accounting for 25 to 40% of outpatients, 15 to 20% of all hospital admissions, and 9 to 14% of all hospital deaths. This situation was exacerbated by The Lord’s Resistance Army (LRA) rebellion in northern Uganda which completely ran down the health care system. While malaria remains the number one killer disease in northern Uganda, antimalarials are lacking in the public health facilities. Consequently, Private-for-profit drug-outlets have come up to help bridge the gap. However, the cost-effectiveness and treatment outcome ratings of antimalarials are not clear. Objective: To assess the pharmacoeconomics of malaria treatment in Private-for-profit (PFP) drug-outlets in Gulu Municipality and Kitgum Town Council. Methodology This was a descriptive cross-sectional study sites were registered drug outlets. Study participants were drug-outlet owners, their employees, and malaria patients. We employed both purposive and random sampling methods to select the study participants. Data were collected using questionnaires and analysed using the SPSS computer package. Results Up to 91.1% of the respondents indicated that antimalarials are expensive. The prices varied from less than 5,000 to over 20,000 Ugandan shillings per dose (Exchange rate: 1$ = Ush 2,650). Fansidar and chloroquine were rated as being relatively cheap and ACTs expensive (Ush 11,000 to 15,000). Duration of treatment, frequency of administration, needles and syringes, raised the cost of some medicines. Most patients preferred cheap medicines (76.2%); those with low administration frequencies (77.5%); and those with short treatment duration (95%). Most patients (80.9%) buy antimalarials without testing, while 66.6% do not buy full doses. Conclusion The cost benefit analysis of the use of antimalarials is unfavourable. The unit price of the medicines, their irrational use and the lack of professionals in the

  5. Structural mapping of the ClpB ATPases of Plasmodium falciparum: Targeting protein folding and secretion for antimalarial drug design

    PubMed Central

    AhYoung, Andrew P; Koehl, Antoine; Cascio, Duilio; Egea, Pascal F

    2015-01-01

    Caseinolytic chaperones and proteases (Clp) belong to the AAA+ protein superfamily and are part of the protein quality control machinery in cells. The eukaryotic parasite Plasmodium falciparum, the causative agent of malaria, has evolved an elaborate network of Clp proteins including two distinct ClpB ATPases. ClpB1 and ClpB2 are involved in different aspects of parasitic proteostasis. ClpB1 is present in the apicoplast, a parasite-specific and plastid-like organelle hosting various metabolic pathways necessary for parasite growth. ClpB2 localizes to the parasitophorous vacuole membrane where it drives protein export as core subunit of a parasite-derived protein secretion complex, the Plasmodium Translocon of Exported proteins (PTEX); this process is central to parasite virulence and survival in the human host. The functional associations of these two chaperones with parasite-specific metabolism and protein secretion make them prime drug targets. ClpB proteins function as unfoldases and disaggregases and share a common architecture consisting of four domains—a variable N-terminal domain that binds different protein substrates, followed by two highly conserved catalytic ATPase domains, and a C-terminal domain. Here, we report and compare the first crystal structures of the N terminal domains of ClpB1 and ClpB2 from Plasmodium and analyze their molecular surfaces. Solution scattering analysis of the N domain of ClpB2 shows that the average solution conformation is similar to the crystalline structure. These structures represent the first step towards the characterization of these two malarial chaperones and the reconstitution of the entire PTEX to aid structure-based design of novel anti-malarial drugs. PMID:26130467

  6. Surveillance of Travellers: An Additional Tool for Tracking Antimalarial Drug Resistance in Endemic Countries

    PubMed Central

    Gharbi, Myriam; Flegg, Jennifer A.; Pradines, Bruno; Berenger, Ako; Ndiaye, Magatte; Djimdé, Abdoulaye A.; Roper, Cally; Hubert, Véronique; Kendjo, Eric; Venkatesan, Meera; Brasseur, Philippe; Gaye, Oumar; Offianan, André T.; Penali, Louis; Le Bras, Jacques; Guérin, Philippe J.; Study, Members of the French National Reference Center for Imported Malaria

    2013-01-01

    Introduction There are growing concerns about the emergence of resistance to artemisinin-based combination therapies (ACTs). Since the widespread adoption of ACTs, there has been a decrease in the systematic surveillance of antimalarial drug resistance in many malaria-endemic countries. The aim of this work was to test whether data on travellers returning from Africa with malaria could serve as an additional surveillance system of local information sources for the emergence of drug resistance in endemic-countries. Methodology Data were collected from travellers with symptomatic Plasmodium falciparum malaria returning from Senegal (n = 1,993), Mali (n = 2,372), Cote d’Ivoire (n = 4,778) or Cameroon (n = 3,272) and recorded in the French Malaria Reference Centre during the period 1996–2011. Temporal trends of the proportion of parasite isolates that carried the mutant genotype, pfcrt 76T, a marker of resistance to chloroquine (CQ) and pfdhfr 108N, a marker of resistance to pyrimethamine, were compared for travellers and within-country surveys that were identified through a literature review in PubMed. The in vitro response to CQ was also compared between these two groups for parasites from Senegal. Results The trends in the proportion of parasites that carried pfcrt 76T, and pfdhfr 108N, were compared for parasites from travellers and patients within-country using the slopes of the curves over time; no significant differences in the trends were found for any of the 4 countries. These results were supported by in vitro analysis of parasites from the field in Senegal and travellers returning to France, where the trends were also not significantly different. Conclusion The results have not shown different trends in resistance between parasites derived from travellers or from parasites within-country. This work highlights the value of an international database of drug responses in travellers as an additional tool to assess the emergence of drug

  7. A New Set of Chemical Starting Points with Plasmodium falciparum Transmission-Blocking Potential for Antimalarial Drug Discovery.

    PubMed

    Almela, Maria Jesus; Lozano, Sonia; Lelièvre, Joël; Colmenarejo, Gonzalo; Coterón, José Miguel; Rodrigues, Janneth; Gonzalez, Carolina; Herreros, Esperanza

    2015-01-01

    The discovery of new antimalarials with transmission blocking activity remains a key issue in efforts to control malaria and eventually eradicate the disease. Recently, high-throughput screening (HTS) assays have been successfully applied to Plasmodium falciparum asexual stages to screen millions of compounds, with the identification of thousands of new active molecules, some of which are already in clinical phases. The same approach has now been applied to identify compounds that are active against P. falciparum gametocytes, the parasite stage responsible for transmission. This study reports screening results for the Tres Cantos Antimalarial Set (TCAMS), of approximately 13,533 molecules, against P. falciparum stage V gametocytes. Secondary confirmation and cytotoxicity assays led to the identification of 98 selective molecules with dual activity against gametocytes and asexual stages. Hit compounds were chemically clustered and analyzed for appropriate physicochemical properties. The TCAMS chemical space around the prioritized hits was also studied. A selection of hit compounds was assessed ex vivo in the standard membrane feeding assay and demonstrated complete block in transmission. As a result of this effort, new chemical structures not connected to previously described antimalarials have been identified. This new set of compounds may serve as starting points for future drug discovery programs as well as tool compounds for identifying new modes of action involved in malaria transmission. PMID:26317851

  8. A New Set of Chemical Starting Points with Plasmodium falciparum Transmission-Blocking Potential for Antimalarial Drug Discovery

    PubMed Central

    Almela, Maria Jesus; Lozano, Sonia; Lelièvre, Joël; Colmenarejo, Gonzalo; Coterón, José Miguel; Rodrigues, Janneth; Gonzalez, Carolina; Herreros, Esperanza

    2015-01-01

    The discovery of new antimalarials with transmission blocking activity remains a key issue in efforts to control malaria and eventually eradicate the disease. Recently, high-throughput screening (HTS) assays have been successfully applied to Plasmodium falciparum asexual stages to screen millions of compounds, with the identification of thousands of new active molecules, some of which are already in clinical phases. The same approach has now been applied to identify compounds that are active against P. falciparum gametocytes, the parasite stage responsible for transmission. This study reports screening results for the Tres Cantos Antimalarial Set (TCAMS), of approximately 13,533 molecules, against P. falciparum stage V gametocytes. Secondary confirmation and cytotoxicity assays led to the identification of 98 selective molecules with dual activity against gametocytes and asexual stages. Hit compounds were chemically clustered and analyzed for appropriate physicochemical properties. The TCAMS chemical space around the prioritized hits was also studied. A selection of hit compounds was assessed ex vivo in the standard membrane feeding assay and demonstrated complete block in transmission. As a result of this effort, new chemical structures not connected to previously described antimalarials have been identified. This new set of compounds may serve as starting points for future drug discovery programs as well as tool compounds for identifying new modes of action involved in malaria transmission. PMID:26317851

  9. Incorporating Stage-Specific Drug Action into Pharmacological Modeling of Antimalarial Drug Treatment

    PubMed Central

    2016-01-01

    Pharmacological modeling of antiparasitic treatment based on a drug's pharmacokinetic and pharmacodynamic properties plays an increasingly important role in identifying optimal drug dosing regimens and predicting their potential impact on control and elimination programs. Conventional modeling of treatment relies on methods that do not distinguish between parasites at different developmental stages. This is problematic for malaria parasites, as their sensitivity to drugs varies substantially during their 48-h developmental cycle. We investigated four drug types (short or long half-lives with or without stage-specific killing) to quantify the accuracy of the standard methodology. The treatment dynamics of three drug types were well characterized with standard modeling. The exception were short-half-life drugs with stage-specific killing (i.e., artemisinins) because, depending on time of treatment, parasites might be in highly drug-sensitive stages or in much less sensitive stages. We describe how to bring such drugs into pharmacological modeling by including additional variation into the drug's maximal killing rate. Finally, we show that artemisinin kill rates may have been substantially overestimated in previous modeling studies because (i) the parasite reduction ratio (PRR) (generally estimated to be 104) is based on observed changes in circulating parasite numbers, which generally overestimate the “true” PRR, which should include both circulating and sequestered parasites, and (ii) the third dose of artemisinin at 48 h targets exactly those stages initially hit at time zero, so it is incorrect to extrapolate the PRR measured over 48 h to predict the impact of doses at 48 h and later. PMID:26902760

  10. The antimalarial drug primaquine targets Fe-S cluster proteins and yeast respiratory growth.

    PubMed

    Lalève, Anaïs; Vallières, Cindy; Golinelli-Cohen, Marie-Pierre; Bouton, Cécile; Song, Zehua; Pawlik, Grzegorz; Tindall, Sarah M; Avery, Simon V; Clain, Jérôme; Meunier, Brigitte

    2016-04-01

    Malaria is a major health burden in tropical and subtropical countries. The antimalarial drug primaquine is extremely useful for killing the transmissible gametocyte forms of Plasmodium falciparum and the hepatic quiescent forms of P. vivax. Yet its mechanism of action is still poorly understood. In this study, we used the yeast Saccharomyces cerevisiae model to help uncover the mode of action of primaquine. We found that the growth inhibitory effect of primaquine was restricted to cells that relied on respiratory function to proliferate and that deletion of SOD2 encoding the mitochondrial superoxide dismutase severely increased its effect, which can be countered by the overexpression of AIM32 and MCR1 encoding mitochondrial enzymes involved in the response to oxidative stress. This indicated that ROS produced by respiratory activity had a key role in primaquine-induced growth defect. We observed that Δsod2 cells treated with primaquine displayed a severely decreased activity of aconitase that contains a Fe-S cluster notoriously sensitive to oxidative damage. We also showed that in vitro exposure to primaquine impaired the activity of purified aconitase and accelerated the turnover of the Fe-S cluster of the essential protein Rli1. It is suggested that ROS-labile Fe-S groups are the primary targets of primaquine. Aconitase activity is known to be essential at certain life-cycle stages of the malaria parasite. Thus primaquine-induced damage of its labile Fe-S cluster - and of other ROS-sensitive enzymes - could inhibit parasite development. PMID:26629948

  11. Low-cost, high-speed identification of counterfeit antimalarial drugs on paper.

    PubMed

    Koesdjojo, Myra T; Wu, Yuanyuan; Boonloed, Anukul; Dunfield, Elizabeth M; Remcho, Vincent T

    2014-12-01

    With the emergence of artesunate antimalarial counterfeiting in Southeast Asia and sub-Saharan Africa, we present the production of a rapid, inexpensive and simple colorimetric-based testing kit for the detection of counterfeit artesunate in order to preserve life and prevent the development of multi-drug resistant malaria. The kit works based on paper microfluidics which offer several advantages over conventional microfluidics, and has great potential to generate inexpensive, easy-to-use, rapid and disposable diagnostic devices. Here, we have developed a colorimetric assay that is specific to artesunate and turns yellow upon addition of the sample. The test can be done within minutes, and allows for a semi-quantitative analysis of the artesunate tablets by comparing the developed yellow color on the paper test to a color-coded key chart that comes with the kit. A more accurate and precise analysis is done by utilizing a color analyzer on an iPhone camera that measures the color intensity of the developed color on the paper chip. A digital image of the chip was taken and analyzed by measuring the average gray intensity of the color developed on the paper circle. A plot of the artesunate concentration versus the average gray scale intensity was generated. Results show that the intensity of the yellow color developed on the paper test was consistent and proportional to the amount of artesunate present in the sample. With artesunate concentrations ranging from 0.0 to 20mg/mL, a linear calibration plot was obtained with a detection limit of 0.98 mg/mL.

  12. Antidiabetic and antimalarial biguanide drugs are metal-interactive antiproteolytic agents.

    PubMed

    Sweeney, Deacon; Raymer, Michael L; Lockwood, Thomas D

    2003-08-15

    Various biguanide derivatives are used as antihyperglycemic and antimalarial drugs (e.g., 1,1-dimethyl biguanide (metformin), phenylethyl biguanide (phenformin), N-(4-chlorophenyl)-N'-(isopropyl)-imidodicarbonimidic diamide (proguanil)); however, no common mechanism has been suggested in these controversial therapeutic actions. Biguanides bind endogenous metals that inhibit cysteine proteases independently, e.g., Zn(2+), Cu(2+), Fe(3+). Here, various biguanide derivatives are reported to be metal-interactive inhibitors of cathepsin B from mammals and falcipain-2 from Plasmodium falciparum. Structural homologies were identified among the Phe-Arg protease substrate motif and the metal complexes of phenformin and proguanil. Molecular modeling revealed that the position of the scissile amide substrate bond corresponds to the biguanide-complexed inhibitory metal when the phenyl groups are homologously aligned. Binding of the phenformin-metal complex within the active site of human cathepsin B was modeled with computational docking. A major binding mode involved binding of the drug phenyl group at the protease S2 subsite, and the complexed inhibitory metal shared between the drug and the protease Cys29-His199 catalytic pair. Cysteine protease inhibition was assayed with carbobenzyloxy-PHE-ARG-7-aminomethylcoumarin substrate. In the absence of metal ions, phenformin was a weakly competitive protease inhibitor (apparent K(i) several microM); however, metformin was noninhibitory. In contrast, the metal complexes of both metformin and phenformin were protease inhibitors with potency at therapeutic concentrations. Biguanide-metal complexes were more potent cysteine protease inhibitors than either the biguanide or metal ions alone, i.e., synergistic. Similar to chloroquine, therapeutic extracellular concentrations of metformin, phenformin, and proguanil caused metal-interactive inhibition of lysosomal protein degradation as bioassayed in primary tissue using perfused

  13. Quinine, an old anti-malarial drug in a modern world: role in the treatment of malaria

    PubMed Central

    2011-01-01

    Quinine remains an important anti-malarial drug almost 400 years after its effectiveness was first documented. However, its continued use is challenged by its poor tolerability, poor compliance with complex dosing regimens, and the availability of more efficacious anti-malarial drugs. This article reviews the historical role of quinine, considers its current usage and provides insight into its appropriate future use in the treatment of malaria. In light of recent research findings intravenous artesunate should be the first-line drug for severe malaria, with quinine as an alternative. The role of rectal quinine as pre-referral treatment for severe malaria has not been fully explored, but it remains a promising intervention. In pregnancy, quinine continues to play a critical role in the management of malaria, especially in the first trimester, and it will remain a mainstay of treatment until safer alternatives become available. For uncomplicated malaria, artemisinin-based combination therapy (ACT) offers a better option than quinine though the difficulty of maintaining a steady supply of ACT in resource-limited settings renders the rapid withdrawal of quinine for uncomplicated malaria cases risky. The best approach would be to identify solutions to ACT stock-outs, maintain quinine in case of ACT stock-outs, and evaluate strategies for improving quinine treatment outcomes by combining it with antibiotics. In HIV and TB infected populations, concerns about potential interactions between quinine and antiretroviral and anti-tuberculosis drugs exist, and these will need further research and pharmacovigilance. PMID:21609473

  14. An amphiphilic graft copolymer-based nanoparticle platform for reduction-responsive anticancer and antimalarial drug delivery

    NASA Astrophysics Data System (ADS)

    Najer, Adrian; Wu, Dalin; Nussbaumer, Martin G.; Schwertz, Geoffrey; Schwab, Anatol; Witschel, Matthias C.; Schäfer, Anja; Diederich, François; Rottmann, Matthias; Palivan, Cornelia G.; Beck, Hans-Peter; Meier, Wolfgang

    2016-08-01

    Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL-1. Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (+/-)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block.Medical applications of anticancer and antimalarial drugs often suffer from low aqueous

  15. Treatment of Plasmodium chabaudi Parasites with Curcumin in Combination with Antimalarial Drugs: Drug Interactions and Implications on the Ubiquitin/Proteasome System

    PubMed Central

    Neto, Zoraima; Machado, Marta; Lindeza, Ana; do Rosário, Virgílio; Gazarini, Marcos L.; Lopes, Dinora

    2013-01-01

    Antimalarial drug resistance remains a major obstacle in malaria control. Evidence from Southeast Asia shows that resistance to artemisinin combination therapy (ACT) is inevitable. Ethnopharmacological studies have confirmed the efficacy of curcumin against Plasmodium spp. Drug interaction assays between curcumin/piperine/chloroquine and curcumin/piperine/artemisinin combinations and the potential of drug treatment to interfere with the ubiquitin proteasome system (UPS) were analyzed. In vivo efficacy of curcumin was studied in BALB/c mice infected with Plasmodium chabaudi clones resistant to chloroquine and artemisinin, and drug interactions were analyzed by isobolograms. Subtherapeutic doses of curcumin, chloroquine, and artemisinin were administered to mice, and mRNA was collected following treatment for RT-PCR analysis of genes encoding deubiquitylating enzymes (DUBs). Curcumin was found be nontoxic in BALB/c mice. The combination of curcumin/chloroquine/piperine reduced parasitemia to 37% seven days after treatment versus the control group's 65%, and an additive interaction was revealed. Curcumin/piperine/artemisinin combination did not show a favorable drug interaction in this murine model of malaria. Treatment of mice with subtherapeutic doses of the drugs resulted in a transient increase in genes encoding DUBs indicating UPS interference. If curcumin is to join the arsenal of available antimalarial drugs, future studies exploring suitable drug partners would be of interest. PMID:23691276

  16. An amphiphilic graft copolymer-based nanoparticle platform for reduction-responsive anticancer and antimalarial drug delivery.

    PubMed

    Najer, Adrian; Wu, Dalin; Nussbaumer, Martin G; Schwertz, Geoffrey; Schwab, Anatol; Witschel, Matthias C; Schäfer, Anja; Diederich, François; Rottmann, Matthias; Palivan, Cornelia G; Beck, Hans-Peter; Meier, Wolfgang

    2016-08-21

    Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL(-1). Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (±)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block. PMID:27452350

  17. Addressing the malaria drug resistance challenge using flow cytometry to discover new antimalarials.

    PubMed

    Grimberg, Brian T; Jaworska, Maria M; Hough, Lindsay B; Zimmerman, Peter A; Phillips, James G

    2009-09-15

    A new flow cytometry method that uses an optimized DNA and RNA staining strategy to monitor the growth and development of the Plasmodium falciparum strain W2mef has been used in a pilot study and has identified Bay 43-9006 1, SU 11274 2, and TMC 125 5 as compounds that exhibit potent (<1 microM) overall and ring stage in vitro antimalarial activity.

  18. Antimalarial Preclinical Drug Development: A Single Oral Dose of A 5-Carbon-linked Trioxane Dimer Plus Mefloquine Cures Malaria-Infected Mice.

    PubMed

    Moon, Deuk Kyu; Singhal, Vandana; Kumar, Nirbhay; Shapiro, Theresa A; Posner, Gary H

    2009-01-01

    Three new 5-carbon-linked trioxane dimer carboxylate esters have been prepared from the natural trioxane, artemisinin in only 3-steps and 40-50% overall yields. Each one of these new chemical entities is at least as efficacious as the clinically used trioxane antimalarial drug artemether when combined with mefloquine hydrochloride in a low single oral dose cure. PMID:20686674

  19. Epidemic of Plasmodium falciparum malaria involving substandard antimalarial drugs, Pakistan, 2003.

    PubMed

    Leslie, Toby; Kaur, Harpakash; Mohammed, Nasir; Kolaczinski, Kate; Ord, Rosalynn L; Rowland, Mark

    2009-11-01

    Because of instability in eastern Afghanistan, new refugees crossed into the federally administered tribal areas of northwestern Pakistan in 2002. In 2003, we investigated an epidemic of Plasmodium falciparum malaria in 1 of the camps. Incidence was 100.4 cases/1,000 person-years; in other nearby camps it was only 2.1/1,000 person-years. Anopheline mosquitoes were found despite an earlier spray campaign. Documented clinical failures at the basic health unit prompted a drug resistance survey of locally manufactured sulfadoxine-pyrimethamine used for routine treatment. The in vivo failure rate was 28.5%. PCR analysis of the P. falciparum dihydrofolate reductase and dihyropteroate synthase genes showed no mutations associated with clinical failure. However, chemical analysis of the drug showed that it was substandard. As global incidence decreases and epidemics become more of a threat, enhanced quality assurance of control interventions is essential. PMID:19891862

  20. Epidemic of Plasmodium falciparum Malaria Involving Substandard Antimalarial Drugs, Pakistan, 2003

    PubMed Central

    Kaur, Harpakash; Mohammed, Nasir; Kolaczinski, Kate; Ord, Rosalynn L.; Rowland, Mark

    2009-01-01

    Because of instability in eastern Afghanistan, new refugees crossed into the federally administered tribal areas of northwestern Pakistan in 2002. In 2003, we investigated an epidemic of Plasmodium falciparum malaria in 1 of the camps. Incidence was 100.4 cases/1,000 person-years; in other nearby camps it was only 2.1/1,000 person-years. Anopheline mosquitoes were found despite an earlier spray campaign. Documented clinical failures at the basic health unit prompted a drug resistance survey of locally manufactured sulfadoxine-pyrimethamine used for routine treatment. The in vivo failure rate was 28.5%. PCR analysis of the P. falciparum dihydrofolate reductase and dihyropteroate synthase genes showed no mutations associated with clinical failure. However, chemical analysis of the drug showed that it was substandard. As global incidence decreases and epidemics become more of a threat, enhanced quality assurance of control interventions is essential. PMID:19891862

  1. Natural polyhydroxyalkanoate-gold nanocomposite based biosensor for detection of antimalarial drug artemisinin.

    PubMed

    Phukon, Pinkee; Radhapyari, Keisham; Konwar, Bolin Kumar; Khan, Raju

    2014-04-01

    The worrisome trend of antimalarial resistance has already highlighted the importance of artemisinin as a potent antimalarial agent. The current investigation aimed at fabricating a biosensor based on natural polymer polyhydroxyalkanoate-gold nanoparticle composite mounting on an indium-tin oxide glass plate for the analysis of artemisinin. The biosensor was fabricated using an adsorbing horse-radish peroxidase enzyme on the electrode surface for which cyclic voltammetry was used to monitor the electro-catalytic reduction of artemisinin under diffusion controlled conditions. Electrochemical interfacial properties and immobilization of enzyme onto a polyhydroxyalkanoate-gold nanoparticle film were evaluated, and confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The differential pulse voltammetric peak current for artemisinin was increased linearly (concentration range of 0.01-0.08μg mL(-1)) with sensitivity of 0.26μAμg mL(-1). The greater sensitivity of the fabricated biosensor to artemisinin (optimum limits of detection were 0.0035μg mL(-1) and 0.0036μg mL(-1) in bulk and spiked human serum, respectively) could be of much aid in medical diagnosis. PMID:24582254

  2. Major Reduction in Anti-Malarial Drug Consumption in Senegal after Nation-Wide Introduction of Malaria Rapid Diagnostic Tests

    PubMed Central

    Thiam, Sylla; Thior, Moussa; Faye, Babacar; Ndiop, Médoune; Diouf, Mamadou Lamine; Diouf, Mame Birame; Diallo, Ibrahima; Fall, Fatou Ba; Ndiaye, Jean Louis; Albertini, Audrey; Lee, Evan; Jorgensen, Pernille; Gaye, Oumar; Bell, David

    2011-01-01

    Background While WHO recently recommended universal parasitological confirmation of suspected malaria prior to treatment, debate has continued as to whether wide-scale use of rapid diagnostic tests (RDTs) can achieve this goal. Adherence of health service personnel to RDT results has been poor in some settings, with little impact on anti-malarial drug consumption. The Senegal national malaria control programme introduced universal parasite-based diagnosis using malaria RDTs from late 2007 in all public health facilities. This paper assesses the impact of this programme on anti-malarial drug consumption and disease reporting. Methods and Findings Nationally-collated programme data from 2007 to 2009 including malaria diagnostic outcomes, prescription of artemisinin-based combination therapy (ACT) and consumption of RDTs in public health facilities, were reviewed and compared. Against a marked seasonal variation in all-cause out-patient visits, non-malarial fever and confirmed malaria, parasite-based diagnosis increased nationally from 3.9% of reported malaria-like febrile illness to 86.0% over a 3 year period. The prescription of ACT dropped throughout this period from 72.9% of malaria-like febrile illness to 31.5%, reaching close equivalence to confirmed malaria (29.9% of 584873 suspect fever cases). An estimated 516576 courses of inappropriate ACT prescription were averted. Conclusions The data indicate high adherence of anti-malarial prescribing practice to RDT results after an initial run-in period. The large reduction in ACT consumption enabled by the move from symptom-based to parasite-based diagnosis demonstrates that effective roll-out and use of malaria RDTs is achievable on a national scale through well planned and structured implementation. While more detailed information on management of parasite-negative cases is required at point of care level to assess overall cost-benefits to the health sector, considerable cost-savings were achieved in ACT

  3. Prevalence of Plasmodium falciparum Molecular Markers of Antimalarial Drug Resistance in a Residual Malaria Focus Area in Sabah, Malaysia

    PubMed Central

    Mohd Abd Razak, Mohd Ridzuan; Abdullah, Noor Rain; Sastu, Umi Rubiah; Imwong, Mallika; Muniandy, Prem Kumar; Saat, Muhammad Nor Farhan; Muhammad, Amirrudin; Jelip, Jenarun; Tikuson, Moizin; Yusof, Norsalleh; Rundi, Christina; Mudin, Rose Nani; Syed Mohamed, Ami Fazlin

    2016-01-01

    Chloroquine (CQ) and fansidar (sulphadoxine-pyrimethamine, SP) were widely used for treatment of Plasmodium falciparum for several decades in Malaysia prior to the introduction of Artemisinin-based Combination Therapy (ACT) in 2008. Our previous study in Kalabakan, located in south-east coast of Sabah showed a high prevalence of resistance to CQ and SP, suggesting the use of the treatment may no longer be effective in the area. This study aimed to provide a baseline data of antimalarial drug resistant markers on P. falciparum isolates in Kota Marudu located in the north-east coast of Sabah. Mutations on genes associated with CQ (pfcrt and pfmdr1) and SP (pfdhps and pfdhfr) were assessed by PCR amplification and restriction fragment length polymorphism. Mutations on the kelch13 marker (K13) associated with artemisinin resistance were determined by DNA sequencing technique. The assessment of pfmdr1 copy number variation associated with mefloquine resistant was done by real-time PCR technique. A low prevalence (6.9%) was indicated for both pfcrt K76T and pfmdr1 N86Y mutations. All P. falciparum isolates harboured the pfdhps A437G mutation. Prevalence of pfdhfr gene mutations, S108N and I164L, were 100% and 10.3%, respectively. Combining the different resistant markers, only two isolates were conferred to have CQ and SP treatment failure markers as they contained mutant alleles of pfcrt and pfmdr1 together with quintuple pfdhps/pfdhfr mutation (combination of pfdhps A437G+A581G and pfdhfr C59R+S108N+I164L). All P. falciparum isolates carried single copy number of pfmdr1 and wild type K13 marker. This study has demonstrated a low prevalence of CQ and SP resistance alleles in the study area. Continuous monitoring of antimalarial drug efficacy is warranted and the findings provide information for policy makers in ensuring a proper malaria control. PMID:27788228

  4. 1993 Sir Henry Wellcome Medal and Prize recipient. The rise and fall of mefloquine as an antimalarial drug in South East Asia.

    PubMed

    Shanks, G D

    1994-04-01

    Mefloquine is an antimalarial drug developed by the U.S. Army Antimalarial Drug Program in conjunction with the World Health Organization and Hoffmann-La Roche to address the problem of chloroquine-resistant falciparum malaria encountered during the Vietnam War. Despite the expenditure of millions of dollars over a 20-year period, it is unlikely that mefloquine will ever be used for U.S. soldiers deployed to South East Asia. Although mefloquine met the specifications set by its developers, its usefulness is now limited by the rapid evolution of drug resistance following its release to the civilian population. Drug development for particular military needs was compromised by a rapid biological response from the parasite and commercial concerns. In an era of shrinking military budgets, military drug development programs will by necessity be more resource constrained, thus yielding fewer new drugs per decade. In the short-term, emphasis should be directed toward adapting available antimicrobial drugs for antimalarial purposes. PMID:20058419

  5. Detection and cartography of the fluorinated antimalarial drug mefloquine in normal and Plasmodium falciparum infected red blood cells by scanning ion microscopy and mass spectrometry.

    PubMed

    Adovelande, J; Boulard, Y; Berry, J P; Galle, P; Slodzian, G; Schrével, J

    1994-01-01

    Due to the presence of fluorine atoms in its molecule, the antimalarial drug mefloquine (MQ) can be easily detected in normal and Plasmodium falciparum infected red blood cells (RBC) by scanning ion microscopy and mass spectrometry. The P falciparum infected RBC exhibited intense distribution of MQ inside the parasite. The main compartments of the parasite which accumulate the drug were the food vacuole and the cytoplasm. The correlation between fluorine (19F-) and phosphorus (31P-) as well as probes for the DNA synthesis (BrdU and IdU) emissions shows that the parasite nucleus is also accessible to the drug. This study demonstrates that SIMS technique on smear preparations is an efficient approach for the direct detection and cartography of fluorinated antimalarial drugs in normal and P falciparum infected RBC, without radioactive labelling.

  6. Open Source Drug Discovery: Highly Potent Antimalarial Compounds Derived from the Tres Cantos Arylpyrroles

    PubMed Central

    2016-01-01

    The development of new antimalarial compounds remains a pivotal part of the strategy for malaria elimination. Recent large-scale phenotypic screens have provided a wealth of potential starting points for hit-to-lead campaigns. One such public set is explored, employing an open source research mechanism in which all data and ideas were shared in real time, anyone was able to participate, and patents were not sought. One chemical subseries was found to exhibit oral activity but contained a labile ester that could not be replaced without loss of activity, and the original hit exhibited remarkable sensitivity to minor structural change. A second subseries displayed high potency, including activity within gametocyte and liver stage assays, but at the cost of low solubility. As an open source research project, unexplored avenues are clearly identified and may be explored further by the community; new findings may be cumulatively added to the present work. PMID:27800551

  7. Temporal trends in prevalence of Plasmodium falciparum drug resistance alleles over two decades of changing antimalarial policy in coastal Kenya.

    PubMed

    Okombo, John; Kamau, Alice W; Marsh, Kevin; Sutherland, Colin J; Ochola-Oyier, Lynette Isabella

    2014-12-01

    Molecular surveillance of drug resistance markers through time provides crucial information on genomic adaptations, especially in parasite populations exposed to changing drug pressures. To assess temporal trends of established genotypes associated with tolerance to clinically important antimalarials used in Kenya over the last two decades, we sequenced a region of the pfcrt locus encompassing codons 72-76 of the Plasmodium falciparum chloroquine resistance transporter, full-length pfmdr1 - encoding multi-drug resistance protein, P-glycoprotein homolog (Pgh1) and pfdhfr encoding dihydrofolate reductase, in 485 archived Plasmodium falciparum positive blood samples collected in coastal Kenya at four different time points between 1995 and 2013. Microsatellite loci were also analyzed to compare the genetic backgrounds of parasite populations circulating before and after the withdrawal of chloroquine and sulfadoxine/pyrimethamine. Our results reveal a significant increase in the prevalence of the pfcrt K76 wild-type allele between 1995 and 2013 from 38% to 81.7% (p < 0.0001). In contrast, we noted a significant decline in wild-type pfdhfr S108 allele (p < 0.0001) culminating in complete absence of this allele in 2013. We also observed a significant increase in the prevalence of the wild-type pfmdr1 N86/Y184/D1246 haplotype from 14.6% in 1995 to 66.0% in 2013 (p < 0.0001) and a corresponding decline of the mutant pfmdr1 86Y/184Y/1246Y allele from 36.4% to 0% in 19 years (p < 0.0001). We also show extensive genetic heterogeneity among the chloroquine-sensitive parasites before and after the withdrawal of the drug in contrast to a selective sweep around the triple mutant pfdhfr allele, leading to a mono-allelic population at this locus. These findings highlight the importance of continual surveillance and characterization of parasite genotypes as indicators of the therapeutic efficacy of antimalarials, particularly in the context of changes in malaria treatment

  8. A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs

    PubMed Central

    2013-01-01

    Background Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. Methods A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator. Results Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy

  9. A single LC-tandem mass spectrometry method for the simultaneous determination of 14 antimalarial drugs and their metabolites in human plasma.

    PubMed

    Hodel, E M; Zanolari, B; Mercier, T; Biollaz, J; Keiser, J; Olliaro, P; Genton, B; Decosterd, L A

    2009-04-01

    Among the various determinants of treatment response, the achievement of sufficient blood levels is essential for curing malaria. For helping us at improving our current understanding of antimalarial drugs pharmacokinetics, efficacy and toxicity, we have developed a liquid chromatography-tandem mass spectrometry method (LC-MS/MS) requiring 200mul of plasma for the simultaneous determination of 14 antimalarial drugs and their metabolites which are the components of the current first-line combination treatments for malaria (artemether, artesunate, dihydroartemisinin, amodiaquine, N-desethyl-amodiaquine, lumefantrine, desbutyl-lumefantrine, piperaquine, pyronaridine, mefloquine, chloroquine, quinine, pyrimethamine and sulfadoxine). Plasma is purified by a combination of protein precipitation, evaporation and reconstitution in methanol/ammonium formate 20mM (pH 4.0) 1:1. Reverse-phase chromatographic separation of antimalarial drugs is obtained using a gradient elution of 20mM ammonium formate and acetonitrile both containing 0.5% formic acid, followed by rinsing and re-equilibration to the initial solvent composition up to 21min. Analyte quantification, using matrix-matched calibration samples, is performed by electro-spray ionization-triple quadrupole mass spectrometry by selected reaction monitoring detection in the positive mode. The method was validated according to FDA recommendations, including assessment of extraction yield, matrix effect variability, overall process efficiency, standard addition experiments as well as antimalarials short- and long-term stability in plasma. The reactivity of endoperoxide-containing antimalarials in the presence of hemolysis was tested both in vitro and on malaria patients samples. With this method, signal intensity of artemisinin decreased by about 20% in the presence of 0.2% hemolysed red-blood cells in plasma, whereas its derivatives were essentially not affected. The method is precise (inter-day CV%: 3.1-12.6%) and sensitive

  10. In Vitro and Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity.

    PubMed

    Lucchi, Naomi W; Komino, Franklin; Okoth, Sheila Akinyi; Goldman, Ira; Onyona, Philip; Wiegand, Ryan E; Juma, Elizabeth; Shi, Ya Ping; Barnwell, John W; Udhayakumar, Venkatachalam; Kariuki, Simon

    2015-12-01

    Malaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203 Plasmodium falciparum malaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzed in vitro for sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms in P. falciparum crt (Pfcrt), Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with the Pfcrt wild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P < 0.0001), and higher proportions of parasites with elevated sensitivity to CQ in vitro. The majority of isolates harbored the wild-type N allele in Pfmdr-1 codon 86 (93.5%), with only 7 (3.50%) samples with the N86Y mutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-type Pfmdr-1 D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Y mutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of the Pfmdr-1 gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya.

  11. In Vitro and Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity

    PubMed Central

    Komino, Franklin; Okoth, Sheila Akinyi; Goldman, Ira; Onyona, Philip; Wiegand, Ryan E.; Juma, Elizabeth; Shi, Ya Ping; Barnwell, John W.; Udhayakumar, Venkatachalam; Kariuki, Simon

    2015-01-01

    Malaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203 Plasmodium falciparum malaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzed in vitro for sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms in P. falciparum crt (Pfcrt), Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with the Pfcrt wild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P < 0.0001), and higher proportions of parasites with elevated sensitivity to CQ in vitro. The majority of isolates harbored the wild-type N allele in Pfmdr-1 codon 86 (93.5%), with only 7 (3.50%) samples with the N86Y mutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-type Pfmdr-1 D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Y mutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of the Pfmdr-1 gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya. PMID:26392510

  12. In Vitro and Molecular Surveillance for Antimalarial Drug Resistance in Plasmodium falciparum Parasites in Western Kenya Reveals Sustained Artemisinin Sensitivity and Increased Chloroquine Sensitivity.

    PubMed

    Lucchi, Naomi W; Komino, Franklin; Okoth, Sheila Akinyi; Goldman, Ira; Onyona, Philip; Wiegand, Ryan E; Juma, Elizabeth; Shi, Ya Ping; Barnwell, John W; Udhayakumar, Venkatachalam; Kariuki, Simon

    2015-12-01

    Malaria control is hindered by the evolution and spread of resistance to antimalarials, necessitating multiple changes to drug policies over time. A comprehensive antimalarial drug resistance surveillance program is vital for detecting the potential emergence of resistance to antimalarials, including current artemisinin-based combination therapies. An antimalarial drug resistance surveillance study involving 203 Plasmodium falciparum malaria-positive children was conducted in western Kenya between 2010 and 2013. Specimens from enrolled children were analyzed in vitro for sensitivity to chloroquine (CQ), amodiaquine (AQ), mefloquine (MQ), lumefantrine, and artemisinin derivatives (artesunate and dihydroartemisinin) and for drug resistance allele polymorphisms in P. falciparum crt (Pfcrt), Pfmdr-1, and the K13 propeller domain (K13). We observed a significant increase in the proportion of samples with the Pfcrt wild-type (CVMNK) genotype, from 61.2% in 2010 to 93.0% in 2013 (P < 0.0001), and higher proportions of parasites with elevated sensitivity to CQ in vitro. The majority of isolates harbored the wild-type N allele in Pfmdr-1 codon 86 (93.5%), with only 7 (3.50%) samples with the N86Y mutant allele (the mutant nucleotide is underlined). Likewise, most isolates harbored the wild-type Pfmdr-1 D1246 allele (79.8%), with only 12 (6.38%) specimens with the D1246Y mutant allele and 26 (13.8%) with mixed alleles. All the samples had a single copy of the Pfmdr-1 gene (mean of 0.907 ± 0.141 copies). None of the sequenced parasites had mutations in K13. Our results suggest that artemisinin is likely to remain highly efficacious and that CQ sensitivity appears to be on the rise in western Kenya. PMID:26392510

  13. Homology modeling and molecular dynamics simulation of N-myristoyltransferase from Plasmodium falciparum: an insight into novel antimalarial drug design.

    PubMed

    Paul, Paulomi; Chowdhury, Abhishek; Das Talukdar, Anupam; Choudhury, Manabendra Dutta

    2015-03-01

    Malaria is an infectious disease caused by parasites of the genus Plasmodium. It leads to approximately 1 million deaths per annum worldwide, with an increase number of 6.27 million deaths in 2012 alone. Validation of new antimalarial targets is very important in the context of the rise in resistance to current drugs. One such putative target is the enzyme N-myristoyltransferase (NMT), which catalyzes the attachment of the fatty acid myristate to protein substrates (N-myristoylation) for activation. Reports suggests that NMT is an essential and chemically docile target in malaria parasites both in vitro and in vivo, and the selective inhibition of N-myristoylation leads to irreversible failure to form an inner membrane complex—an essential subcellular organelle in the parasite life cycle. In this work, we modeled the three-dimensional structure of Plasmodium falciparum NMT (PfNMT) using Modeler 9.0 taking Plasmodium vivax NMT (PvNMT) as the template. The novelty of the work lies in the selection of template as the similarity of PfNMT with PvNMT was 80.47%, whereas earlier similar work showed template similarity with Candida albicans NMT (CaNMT) and Saccharomyces cerevisiae NMT (ScNMT) to be less than 50%. The generated structure was then validated using various programs such as PROCHECK, RAMPAGE server, CHIMERA and the stability of the model was checked by Gromacs 5.0.

  14. Pharmacokinetics of a novel sublingual spray formulation of the antimalarial drug artemether in African children with malaria.

    PubMed

    Salman, Sam; Bendel, Daryl; Lee, Toong C; Templeton, David; Davis, Timothy M E

    2015-01-01

    The pharmacokinetics of sublingual artemether (ArTiMist) was investigated in 91 young African children with severe malaria or who could not tolerate oral antimalarial therapy. Each received 3.0 mg/kg of body weight of artemether at 0, 8, 24, 36, 48, and 60 h or until the initiation of oral treatment. Few blood samples were drawn postdose. Plasma artemether and dihydroartemisinin (DHA) levels were measured using liquid chromatography-mass spectrometry, and the data were analyzed using established population compartmental pharmacokinetic models. Parasite clearance was prompt (median parasite clearance time, 24 h), and there were no serious adverse events. Consistent with studies in healthy adults (S. Salman, D. Bendel, T. C. Lee, D. Templeton, and T. M. E. Davis, Antimicrob Agents Chemother 59:3197-3207, 2015, http://dx.doi.org/10.1128/AAC.05013-14), the absorption of sublingual artemether was biphasic, and multiple dosing was associated with the autoinduction of the metabolism of artemether to DHA (which itself has potent antimalarial activity). In contrast to studies using healthy volunteers, pharmacokinetic modeling indicated that the first absorption phase did not avoid first-pass metabolism, suggesting that the drug is transferred to the upper intestine through postdose fluid/food intake. Simulations using the present data and those from an earlier study in older Melanesian children with uncomplicated malaria treated with artemether-lumefantrine tablets suggested that the bioavailability of sublingual artemether was at least equivalent to that after conventional oral artemether-lumefantrine (median [interquartile range] areas under the concentration-time curve for artemether, 3,403 [2,471 to 4,771] versus 3,063 [2,358 to 4,514] μg · h/liter, respectively; and for DHA, 2,958 [2,146 to 4,278] versus 2,839 [1,812 to 3,488] μg · h/liter, respectively; P ≥ 0.42). These findings suggest that sublingual artemether could be used as prereferral treatment for sick

  15. Determination of log P values of new cyclen based antimalarial drug leads using RP-HPLC.

    PubMed

    Rudraraju, A V; Amoyaw, P N A; Hubin, T J; Khan, M O F

    2014-09-01

    Lipophilicity, expressed by log P, is an important physicochemical property of drugs that affects many biological processes, including drug absorption and distribution. The main purpose of this study to determine the log P values of newly discovered drug leads using reversed-phase high-performance liquid chromatography (RP-HPLC). The reference standards, with varying polarity ranges, were dissolved in methanol and analyzed by RP-HPLC using a C18 column. The mobile phase consisted of a mixture of acetonitrile, methanol and water in a gradient elution mode. A calibration curve was plotted between the experimental log P values and obtained log k values of the reference standard compounds and a best fit line was obtained. The log k values of the new drug leads were determined in the same solvent system and were used to calculate the respective log P values by using the best fit equation. The log P vs. log k data gave a best fit linear curve that had an R2 of 0.9786 with Pvalues of the intercept and slope of 1.19 x 10(-6) and 1.56 x 10(-10), respectively, at 0.05 level of significance. Log P values of 15 new drug leads and related compounds, all of which are derivatives of macrocyclic polyamines and their metal complexes, were determined. The values obtained are closely related to the calculated log P (Clog P) values using ChemDraw Ultra 12.0. This experiment provided efficient, fast and reasonable estimates of log P values of the new drug leads by using RP-HPLC.

  16. The quality of antimalarial medicines in eastern Thailand: a case study along the Thai-Cambodian border.

    PubMed

    Phanouvong, Souly; Dijiba, Yanga; Vijaykadga, Saowanit; Raymond, Christopher; Krech, Laura; Lukulay, Patrick; Satimai, Wichai; Tanunkat, Orapin; Sook-Kam, Sanya

    2013-05-01

    This study examined the prevalence, availability, and use of antimalarial medicines (AMLs) along the Thai-Cambodian border. The study was divided into two parts: the first looked at the quality of AMLs available in six Thai provinces and the second obtained information about the availability and use of AMLs. A randomized sampling methodology was used to select locations and collect samples, which were screened using Global Pharma Health Fund (GPHF) Minilabs. A subset of samples was sent to quality control laboratories for verification testing. For the second part of the study, face-to-face interviews were conducted with members of randomly selected households and the staff of health facilities in villages with the highest malaria incidence to find out where they acquired their AMLs and which were used most frequently. The results of quality testing showed an overall failure rate of 1% (7 of 709 samples) for active pharmaceutical ingredients (API); however, the API failure rate varied from 0.0% to 2.2% by location and the overall failure rates of samples by province varied from 0.0% to 3.4%. A total of 97.9% (n = 272) of respondents had taken AMLS. The most commonly used medicines were primaquine (30% of respondents), chloroquine (15.8%), artesunate+mefloquine (12%), and quinine (10%). Most respondents (97.9%) had received medications from public hospitals or malaria clinics.

  17. A Physico-Biochemical Study on Potential Redox-Cyclers as Antimalarial and Antischistosomal Drugs

    PubMed Central

    Johann, Laure; Lanfranchi, Don Antoine; Davioud-Charvet, Elisabeth; Elhabiri, Mourad

    2013-01-01

    The role of redox enzymes in establishing a microenvironment for parasite development is well characterized. Mimicking human glucose-6-phosphate dehydrogenase and glutathione reductase (GR) deficiencies by redox-cycling compounds thus represents a challenge to the design of new preclinical antiparasitic drug candidates. Schistosomes and malarial parasites feed on hemoglobin. Heme, the toxic prosthetic group of the protein, is not digested and represents a challenge to the redox metabolism of the parasites. Here, we report on old and new redox-cycling compounds – whose antiparasitic activities are related to their interference with (met)hemoglobin degradation and hematin crystallization. Three key-assays allowed probing and differentiating the mechanisms of drug actions. Inhibition of β-hematin was first compared to the heme binding as a possible mode of action. All tested ligands interact with the hematin π-π dimer with KD similar to those measured for the major antiparasitic drugs. No correlation between a high affinity for hematin and the capacity to prevent β-hematin formation was however deduced. Inhibition of β-hematin formation is consequently not the result of a single process but results from redox processes following electron transfers from the drugs to iron(III)-containing targets. The third experiment highlighted that several redox-active compounds (in their reduced forms) are able to efficiently reduce methemoglobin to hemoglobin in a GR/NADPH-coupled assay. A correlation between methemoglobin reduction and inhibition of β-hematin was shown, demonstrating that both processes are closely related. The ability of our redox-cyclers to trigger methemoglobin reduction therefore constitutes a critical step to understand the mechanism of action of our drug candidates. PMID:22607146

  18. Inhibition of native 5-HT3 receptor-evoked contractions in guinea pig and mouse ileum by antimalarial drugs.

    PubMed

    Kelley, Stephen P; Walsh, Jacqueline; Kelly, Mark C; Muhdar, Simerjyot; Adel-Aziz, Mohammed; Barrett, Iain D; Wildman, Scott S

    2014-09-01

    Quinine, chloroquine and mefloquine are commonly used to treat malaria, however, with associated gastrointestinal (GI) side-effects. These drugs act as antagonists at recombinant 5-HT3 receptors and modulate gut peristalsis. These gastrointestinal side effects may be the result of antagonism at intestinal 5-HT3 receptors. Ileum from male C57BL/6 mice and guinea pigs was mounted longitudinally in organ baths. The concentration-response curves for 5-HT and the selective 5-HT3 agonist 2-Me-5-HT were obtained with 5-HT (pEC50 = 7.57 ± 0.33, 12) more potent (P = 0.004) than 2-Me-5-HT (pEC50 = 5.45 ± 0.58, n = 5) in mouse ileum. There was no difference in potency of 5-HT (pEC50 = 5.42 ± 0.15, n = 8) and 2-Me-5-HT (pIC50 = 5.01 ± 0.55, n = 11) in guinea pig ileum (P > 0.05). Quinine, chloroquine or mefloquine was applied for 10 min and inhibitions prior to submaximal agonist application. In mouse ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 4.9 ± 0.17, n = 7; 4.76 ± 0.14, n = 5; 6.21 ± 0.2, n = 4, correspondingly) with mefloquine most potent (P < 0.05). Quinine, chloroquine and mefloquine antagonised 2-me-5-HT-induced contractions (pIC50 = 6.35 ± 0.11, n = 8; 4.64 ± 0.2, n = 7; 5.11 ± 0.22, n = 6, correspondingly) with quinine most potent (P < 0.05). In guinea-pig ileum, quinine, chloroquine and mefloquine antagonised 5-HT-induced contractions (pIC50 = 5.02 ± 0.15, n = 6; 4.54 ± 0.1, n = 7; 5.32 ± 0.13, n = 5) and 2-me-5-HT-induced contractions (pIC50 = 4.62 ± 0.25, n = 5; 4.56 ± 0.14, n = 6; 5.67 ± 0.12, n = 4) with chloroquine least potent against 5-HT and mefloquine most potent against 2-me-5-HT (P < 0.05). These results support previous studies identifying anti-malarial drugs as antagonists at recombinant 5-HT3 receptors and may also demonstrate the ability of these drugs to influence native 5-HT3 receptor-evoked contractile responses which may account for their associated GI side-effects. PMID:24886883

  19. Malaria Related Perceptions, Care Seeking after Onset of Fever and Anti-Malarial Drug Use in Malaria Endemic Settings of Southwest Ethiopia

    PubMed Central

    Birhanu, Zewdie; Abebe, Lakew; Sudhakar, Morankar; Dissanayake, Gunawardena; Yihdego, Yemane Ye-ebiyo; Alemayehu, Guda; Yewhalaw, Delenasaw

    2016-01-01

    Background Prompt care seeking and appropriate use of anti-malarial drugs are critical components of malaria prevention and control. This study assessed malaria related perceptions, care seeking behavior and anti-malarial drug use in malaria endemic settings of Ethiopia. Methods Data were generated from a community based cross-sectional study conducted among 798 households during January 2014 as part of a larger household behavioral study in three malaria endemic districts of Jimma Zone, Southwest Ethiopia. Both quantitative and qualitative data were collected and analyzed using SPSS 17.0 and STATA 12.0. Results In this study, only 76.1% of the respondents associated malaria to mosquito bite, and incorrect beliefs and perceptions were noted. Despite moderate level of knowledge (estimated mean = 62.2, Std Err = 0.7, 95% CI: 60.6–63.8%), quite high favorable attitude (overall estimated mean = 91.5, Std Err = 0.6, 95% CI: 90.1–92.9%) were recorded towards malaria preventive measures. The mean attitude score for prompt care seeking, appropriate use of anti-malarial drugs, LLIN use and Indoor Residual Spray acceptance was 98.5 (Std Err = 0.4, 95% CI:97.5–99.4), 92.7 (Std Err = 0.6 95% CI:91.5–93.9), 88.8 (Std Err = 0.5, 95% CI:85.5–92.1) and 86.5 (Std Err = 1.2, 95% CI: 83.9–89.1), respectively. The prevalence of fever was 2.9% (116/4107) and of the study participants with fever, 71.9% (95% CI: 65.5–78.3%) sought care and all of them consulted formal health care system. However, only 17 (19.8%) sought care within 24 hours after onset of fever. The frequency of care seeking was higher (77.8%, n = 21/27) and more prompt (28.6%, 6/21) for children under five as compared to old age groups despite it was not statistically significant (p > 0.05). However, higher median time of seeking first care was observed among Muslims and people who did not attend school (p < 0.05). Of those who used anti-malarial drugs, 9.1% indicated that they used it inappropriately

  20. Molecular diagnosis of resistance to antimalarial drugs during epidemics and in war zones.

    PubMed

    Djimdé, Abdoulaye A; Dolo, Amagana; Ouattara, Amed; Diakité, Sira; Plowe, Christopher V; Doumbo, Ogobara K

    2004-08-15

    Plasmodium falciparum mutations pfcrt K76T and the dhfr/dhps "quintuple mutant" are molecular markers of resistance to chloroquine and sulfadoxine-pyrimethamine, respectively. During an epidemic of P. falciparum malaria in an area of political unrest in northern Mali, where standard efficacy studies have been impossible, we measured the prevalence of these markers in a cross-sectional survey. In 80% of cases of infection, pfcrt K76T was detected, but none of the cases carried the dhfr/dhps quintuple mutant. On the basis of these results, chloroquine was replaced by sulfadoxine-pyrimethamine in control efforts. This example illustrates how molecular markers for drug resistance can provide timely data that inform malaria-control policy during epidemics and other emergency situations.

  1. Assessment of causal prophylactic activity in Plasmodium berghei yoelii and its value for the development of new antimalarial drugs*

    PubMed Central

    Fink, E.

    1974-01-01

    The causal prophylactic activity of several reference and experimental antimalarial compounds was assessed in sporozoite-induced infections of NMRI mice with Plasmodium berghei yoelii (strain 17X). The animals were inoculated with 10 000 sporozoites per mouse and treated once 2-4 hours later. The test system has proved to be very suitable in experiments involving more than 3 000 mice. The infection rate in 448 untreated controls was 97.3%. Lowering the sporozoite content of the inoculum to 1 000 or 100 sporozoites markedly reduced the rate (65.1% and 32.7%). In experiments with primaquine the causal prophylactic activity was also influenced by the time of drug administration before or after sporozoite inoculation. No causal prophylactic effect was demonstrable with quinine, chloroquine, amodiaquine, amopyroquine, RC-12, or B 505. Primaquine was active, but pamaquine and pentaquine were only sporadically active. The pre-erythrocytic stages of P. b. yoelii were only slightly sensitive to dapsone, sulfadiazine, and sulformethoxine; they were 10-100 times more susceptible to proguanil, cycloguanil, and pyrimethamine. The experimental 6-aminoquinolines NI 147/36, NI 187/82, and BA 138/111 and the 7-chlorolincomycin derivative U 24729 were also studied. Experiments in which curative activity against blood-induced infections of P. b. yoelii was evaluated showed that the causal prophylactics act more specifically against the pre-erythrocytic than against the erythrocytic forms. This specificity was most pronounced among the DHFR-inhibitors, whose outstanding activity may be explained by the fact that the rate of multiplication of the pre-erythrocytic forms of P. b. yoelii is greater than that of other plasmodia used hitherto; it is also greater than the rate shown by the malaria parasites of man and that of the erythrocytic forms of P. b. yoelii itself. We believe that this feature will render P. b. yoelii very useful for determination of the causal prophylactic activity

  2. Plants as Sources of Antimalarial Drugs Part. 1. In vitro Test Method for the Evaluation of Crude Extracts from Plants.

    PubMed

    O'neill, M J; Bray, D H; Boardman, P; Phillipson, J D; Warhurst, D C

    1985-10-01

    An IN VITRO antimalarial test, utilising the inhibition of uptake of [G- (3)H]-hypoxanthine into PLASMODIUM FALCIPARUM cultured in human blood, has been used to assess the activity of crude extracts of ARTEMISIA ANNUA and A. VULGARIS (Compositae) and of BRUCEA JAVANICA, AILANTHUS ALTISSIMA, and SIMABA CEDRON (Simaroubaceae).

  3. Factors related to compliance to anti-malarial drug combination: example of amodiaquine/sulphadoxine-pyrimethamine among children in rural Senegal

    PubMed Central

    Souares, Aurélia; Lalou, Richard; Sene, Ibra; Sow, Diarietou; Le Hesran, Jean-Yves

    2009-01-01

    Background The introduction of new anti-malarial treatment that is effective, but more expensive, raises questions about whether the high level of effectiveness observed in clinical trials can be found in a context of family use. The objective of this study was to determine the factors related to adherence, when using the amodiaquine/sulphadoxine-pyrimethamine (AQ/SP) association, a transitory strategy before ACT implementation in Senegal. Methods The study was conducted in five rural dispensaries. Children, between two and 10 years of age, who presented mild malaria were recruited at the time of the consultation and were prescribed AQ/SP. The child's primary caretaker was questioned at home on D3 about treatment compliance and factors that could have influenced his or her adherence to treatment. A logistic regression model was used for the analyses. Results The study sample included 289 children. The adherence rate was 64.7%. Two risks factors for non-adherence were identified: the children's age (8–10 years) (ORa = 3.07 [1.49–6.29]; p = 0.004); and the profession of the head of household (retailer/employee versus farmer) (ORa = 2.71 [1.34–5.48]; p = 0.006). Previously seeking care (ORa = 0.28 [0.105–0.736], p=0.001] satisfaction with received information (ORa = 0.45 [0.24–0.84]; p = 0.013), and the quality of history taking (ORa = 0.38 [0.21–0.69]; p = 0.001) were significantly associated with good compliance. Conclusion The results of the study show the importance of information and communication between caregivers and health center staff. The experience gained from this therapeutic transition emphasizes the importance of information given to the patients at the time of the consultation and drug delivery in order to improve drug use and thus prevent the emergence of rapid drug resistance. PMID:19497103

  4. Markers of anti-malarial drug resistance in Plasmodium falciparum isolates from Swaziland: identification of pfmdr1-86F in natural parasite isolates

    PubMed Central

    2010-01-01

    Background The development of Plasmodium falciparum resistance to chloroquine (CQ) has limited its use in many malaria endemic areas of the world. However, despite recent drug policy changes to adopt the more effective artemisinin-based combination (ACT) in Africa and in the Southern African region, in 2007 Swaziland still relied on CQ as first-line anti-malarial drug. Methods Parasite DNA was amplified from P. falciparum isolates from Swaziland collected in 1999 (thick smear blood slides) and 2007 (filter paper blood spots). Markers of CQ and sulphadoxine-pyrimethamine (SP) resistance were identified by probe-based qPCR and DNA sequencing. Results Retrospective microscopy, confirmed by PCR amplification, found that only six of 252 patients treated for uncomplicated malaria in 2007 carried detectable P. falciparum. The pfcrt haplotype 72C/73V/74I/75E/76T occurred at a prevalence of 70% (n = 64) in 1999 and 83% (n = 6) in 2007. Prevalence of the pfmdr1-86N allele was 24% in 1999 and 67% in 2007. A novel substitution of phenylalanine for asparagine at codon 86 of pfmdr1 (N86F) occurred in two of 51 isolates successfully amplified from 1999. The pfmdr1-1246Y allele was common in 1999, with a prevalence of 49%, but was absent among isolates collected in 2007. The 86N/184F/1246D pfmdr1 haplotype, associated with enhanced parasite survival in patients treated with artemether-lumefantrine, comprised 8% of 1999 isolates, and 67% among 2007 isolates. The pfdhfr triple-mutant 16C/51I/59R/108N/164I haplotype associated with pyrimethamine resistance was common in both 1999 (82%, n = 34) and 2007 (50%, n = 6), as was the wild-type 431I/436S/437A/540K/581A/613A haplotype of pfdhps (100% and 93% respectively in 1999 and 2007). The quintuple-mutant haplotype pfdhfr/pfdhps-CIRNI/ISGEAA, associated with high-level resistance to SP, was rare (9%) among 1999 isolates and absent among 2007 isolates. Conclusions The prevalence of pfcrt and pfmdr1 alleles reported in this study is

  5. Characterization of the Plasmodium falciparum M17 leucyl aminopeptidase. A protease involved in amino acid regulation with potential for antimalarial drug development.

    PubMed

    Stack, Colin M; Lowther, Jonathan; Cunningham, Eithne; Donnelly, Sheila; Gardiner, Donald L; Trenholme, Katharine R; Skinner-Adams, Tina S; Teuscher, Franka; Grembecka, Jolanta; Mucha, Artur; Kafarski, Pawel; Lua, Linda; Bell, Angus; Dalton, John P

    2007-01-19

    Amino acids generated from the catabolism of hemoglobin by intra-erythrocytic malaria parasites are not only essential for protein synthesis but also function in maintaining an osmotically stable environment, and creating a gradient by which amino acids that are rare or not present in hemoglobin are drawn into the parasite from host serum. We have proposed that a Plasmodium falciparum M17 leucyl aminopeptidase (PfLAP) generates and regulates the internal pool of free amino acids and therefore represents a target for novel antimalarial drugs. This enzyme has been expressed in insect cells as a functional 320-kDa homo-hexamer that is optimally active at neutral or alkaline pH, is dependent on metal ions for activity, and exhibits a substrate preference for N-terminally exposed hydrophobic amino acids, particularly leucine. PfLAP is produced by all stages in the intra-erythrocytic developmental cycle of malaria but was most highly expressed by trophozoites, a stage at which hemoglobin degradation and parasite protein synthesis are elevated. The enzyme was located by immunohistochemical methods and by transfecting malaria cells with a PfLAP-green fluorescent protein construct, to the cytosolic compartment of the cell at all developmental stages, including segregated merozoites. Amino acid dipeptide analogs, such as bestatin and its derivatives, are potent inhibitors of the protease and also block the growth of P. falciparum malaria parasites in culture. This study provides a biochemical basis for the antimalarial activity of aminopeptidase inhibitors. Availability of functionally active recombinant PfLAP, coupled with a simple enzymatic readout, will aid medicinal chemistry and/or high throughput approaches for the future design/discovery of new antimalarial drugs. PMID:17107951

  6. Research influence on antimalarial drug policy change in Tanzania: case study of replacing chloroquine with sulfadoxine-pyrimethamine as the first-line drug

    PubMed Central

    Mubyazi, Godfrey M; Gonzalez-Block, Miguel A

    2005-01-01

    Introduction Research is an essential tool in facing the challenges of scaling up interventions and improving access to services. As in many other countries, the translation of research evidence into drug policy action in Tanzania is often constrained by poor communication between researchers and policy decision-makers, individual perceptions or attitudes towards the drug and hesitation by some policy decision-makers to approve change when they anticipate possible undesirable repercussions should the policy change as proposed. Internationally, literature on the role of researchers on national antimalarial drug policy change is limited. Objectives To describe the (a) role of researchers in producing evidence that influenced the Tanzanian government replace chloroquine (CQ) with sulfadoxine-pyrimethamine (SP) as the first-line drug and the challenges faced in convincing policy-makers, general practitioners, pharmaceutical industry and the general public on the need for change (b) challenges ahead before a new drug combination treatment policy is introduced in Tanzania. Methods In-depth interviews were held with national-level policy-makers, malaria control programme managers, pharmaceutical officers, general medical practitioners, medical research library and publications officers, university academicians, heads of medical research institutions and district and regional medical officers. Additional data were obtained through a review of malaria drug policy documents and participant observations were also done. Results In year 2001, the Tanzanian Government officially changed its malaria treatment policy guidelines whereby CQ – the first-line drug for a long time was replaced with SP. This policy decision was supported by research evidence indicating parasite resistance to CQ and clinical CQ treatment failure rates to have reached intolerable levels as compared to SP and amodiaquine (AQ). Research also indicated that since SP was also facing rising resistance trend

  7. The quality of antimalarial medicines in western Cambodia: a case study along the Thai-Cambodian border.

    PubMed

    Phanouvong, Souly; Raymond, Christopher; Krech, Laura; Dijiba, Yanga; Mam, Boravann; Lukulay, Patrick; Socheat, Duong; Sovannarith, Tey; Sokhan, Chroeng

    2013-05-01

    The prevalence, availability, and use of antimalarial medicines (AMLs) were studied in six Cambodian provinces along the Thai-Cambodian border. The study was divided into two parts: the first looked at the quality of AMLs available in Pursat, Pailin, Battambang, Bantey Meanchey, Oddar Meanchey, and Preah Vihear and the second obtained information about the availability and use of AMLs. A randomized sampling methodology was used to select locations and collect samples, which were screened using Global Pharma Health Fund (GPHF) Minilabs. A subset of samples was sent to quality control laboratories for confirmatory testing. For the second part of the study, face-to-face interviews were conducted using standardized surveys with members of randomly selected households and staff of health facilities in the villages with highest malaria incidence to find out where they acquired their AMLs and which were most frequently used. The results showed an overall failure rate of 12.3% (n = 46 of 374 total AML samples). The causes of medication sample failure were low active pharmaceutical ingredient (API) content, failed dissolution properties, and unacceptably high levels of impurities. A total of 86.2% of survey respondents (n = 1,648 of 1,912) reported a member of their household having malaria in the previous year. The most commonly used medicines were paracetamol (67.1% of respondents), Malarine (A+M co-blistered, 28.6%), artesunate + mefloquine co-blistered (public sector product, 17.3%), quinine (16.7%), and artesunate monotherapy (11.9%). Health staff typically prescribed co-blistered artesunate plus mefloquine in the public sector (67.8%), the artesunate plus mefloquine "social marketing" product from Population Services International (PSI), Malarine (50.3%) in the private sector, artemether (49.7%), chloroquine (39%) and paracetamol (72.9%) to reduce fever.

  8. Induction of multiple pleiotropic drug resistance genes in yeast engineered to produce an increased level of anti-malarial drug precursor, artemisinic acid

    PubMed Central

    Ro, Dae-Kyun; Ouellet, Mario; Paradise, Eric M; Burd, Helcio; Eng, Diana; Paddon, Chris J; Newman, Jack D; Keasling, Jay D

    2008-01-01

    Background Due to the global occurrence of multi-drug-resistant malarial parasites (Plasmodium falciparum), the anti-malarial drug most effective against malaria is artemisinin, a natural product (sesquiterpene lactone endoperoxide) extracted from sweet wormwood (Artemisia annua). However, artemisinin is in short supply and unaffordable to most malaria patients. Artemisinin can be semi-synthesized from its precursor artemisinic acid, which can be synthesized from simple sugars using microorganisms genetically engineered with genes from A. annua. In order to develop an industrially competent yeast strain, detailed analyses of microbial physiology and development of gene expression strategies are required. Results Three plant genes coding for amorphadiene synthase, amorphadiene oxidase (AMO or CYP71AV1), and cytochrome P450 reductase, which in concert divert carbon flux from farnesyl diphosphate to artemisinic acid, were expressed from a single plasmid. The artemisinic acid production in the engineered yeast reached 250 μg mL-1 in shake-flask cultures and 1 g L-1 in bio-reactors with the use of Leu2d selection marker and appropriate medium formulation. When plasmid stability was measured, the yeast strain synthesizing amorphadiene alone maintained the plasmid in 84% of the cells, whereas the yeast strain synthesizing artemisinic acid showed poor plasmid stability. Inactivation of AMO by a point-mutation restored the high plasmid stability, indicating that the low plasmid stability is not caused by production of the AMO protein but by artemisinic acid synthesis or accumulation. Semi-quantitative reverse-transcriptase (RT)-PCR and quantitative real time-PCR consistently showed that pleiotropic drug resistance (PDR) genes, belonging to the family of ATP-Binding Cassette (ABC) transporter, were massively induced in the yeast strain producing artemisinic acid, relative to the yeast strain producing the hydrocarbon amorphadiene alone. Global transcriptional analysis by

  9. Antimalarial properties of orally active iron chelators.

    PubMed

    Heppner, D G; Hallaway, P E; Kontoghiorghes, G J; Eaton, J W

    1988-07-01

    The appearance of widespread multiple drug resistance in human malaria has intensified the search for new antimalarial compounds. Metal chelators, especially those with high affinity for iron, represent one presently unexploited class of antimalarials. Unfortunately the use of previously identified chelators as antimalarials has been precluded by their toxicity and, in the case of desferrioxamine, the necessity for parenteral administration. The investigators now report that a new class of orally active iron chelators, namely the derivatives of alpha-ketohydroxypyridines (KHPs), are potent antimalarials against cultured Plasmodium falciparum. The KHPs evidently exert this effect by sequestering iron because a preformed chelator:iron complex has no antimalarial action. The pool(s) of iron being sequestered by the chelators have not been identified but may not include serum transferrin. Preincubation of human serum with KHPs followed by removal of the drug results in the removal of greater than 97% of total serum iron. Nonetheless, this serum effectively supports the growth of P falciparum cultures. Therefore the KHPs may exert antimalarial effect through chelation of erythrocytic rather than serum iron pool(s). The investigators conclude that these powerful, orally active iron chelators may form the basis of a new class of antimalarial drugs. PMID:3291984

  10. Comparative protein modeling of 1-deoxy-D-xylulose-5-phosphate reductoisomerase enzyme from Plasmodium falciparum: a potential target for antimalarial drug discovery.

    PubMed

    Singh, Nidhi; Chevé, Gwénaël; Avery, Mitchell A; McCurdy, Christopher R

    2006-01-01

    Plasmodium falciparum 1-deoxy-D-xylulose-5-phosphate reductoisomerase (Pf-DXR) is a potential target for antimalarial chemotherapy. The three-dimensional model (3D) of this enzyme was determined by means of comparative modeling through multiple alignment followed by intensive optimization, minimization, and validation. The resulting model demonstrates a reasonable topology as gauged from the Ramachandran plot and acceptable three-dimensional structure compatibility as assessed by the Profiles-3D score. The modeled monomeric subunit consists of three domains: (1) N-terminal NADPH binding domain, (2) connective or linker domain (with most of the active site residues located in this domain), and (3) a C-terminal domain. This structure proved to be consistent with known DXR crystal structures from other species. The predicted active site compared favorably with those of the templates and appears to have an active site with a highly conserved architecture. Additionally, the model explains several site-directed mutagenesis data. Besides using several protein structure-checking programs to validate the model, a set of known inhibitors of DXR were also docked into the active site of the modeled Pf-DXR. The docked scores correlated reasonably well with experimental pIC50 values with a regression coefficient (R2) equal to 0.84. Results of the current study should prove useful in the early design and development of inhibitors by either de novo drug design or virtual screening of large small-molecule databases leading to development of new antimalarial agents. PMID:16711755

  11. High School Students Are a Target Group for Fight against Self-Medication with Antimalarial Drugs: A Pilot Study in University of Kinshasa, Democratic Republic of Congo

    PubMed Central

    Kabongo Kamitalu, Ramsès; Aloni, Michel Ntetani

    2016-01-01

    Aim. To assess the self-medication against malaria infection in population of Congolese students in Kinshasa, Democratic Republic of Congo (DRC). Methods. A cross-sectional study was carried out in University of Kinshasa, Kinshasa, Democratic Republic of Congo. Medical records of all students with malaria admitted to Centre de Santé Universitaire of University of Kinshasa from January 1, 2008, to April 30, 2008, were reviewed retrospectively. Results. The median age of the patients was 25.4 years (range: from 18 to 36 years). The majority of them were male (67.9%). Artemisinin-based combination treatments (ACTs) was the most used self-prescribed antimalarial drugs. However, self-medication was associated with the ingestion of quinine in 19.9% of cases. No case of ingestion of artesunate/artemether in monotherapy was found. All the medicines taken were registered in DRC. In this series, self-prescribed antimalarial was very irrational in terms of dose and duration of treatment. Conclusion. This paper highlights self-medication by a group who should be aware of malaria treatment protocols. The level of self-prescribing quinine is relatively high among students and is disturbing for a molecule reserved for severe disease in Congolese health care policy in management of malaria. PMID:27340411

  12. Absence of Association between Polymorphisms in the RING E3 Ubiquitin Protein Ligase Gene and Ex Vivo Susceptibility to Conventional Antimalarial Drugs in Plasmodium falciparum Isolates from Dakar, Senegal.

    PubMed

    Gendrot, Mathieu; Fall, Bécaye; Madamet, Marylin; Fall, Mansour; Wade, Khalifa Ababacar; Amalvict, Rémy; Nakoulima, Aminata; Benoit, Nicolas; Diawara, Silman; Diémé, Yaya; Diatta, Bakary; Wade, Boubacar; Pradines, Bruno

    2016-08-01

    The RING E3 ubiquitin protein ligase is crucial for facilitating the transfer of ubiquitin. The only polymorphism identified in the E3 ubiquitin protein ligase gene was the D113N mutation (62.5%) but was not significantly associated with the 50% inhibitory concentration (IC50) of conventional antimalarial drugs. However, some mutated isolates (D113N) present a trend of reduced susceptibility to piperaquine (P = 0.0938). To evaluate the association of D113N polymorphism with susceptibility to antimalarials, more isolates are necessary. PMID:27185795

  13. Use of bacterial surrogates as a tool to explore antimalarial drug interaction: Synergism between inhibitors of malarial dihydrofolate reductase and dihydropteroate synthase.

    PubMed

    Talawanich, Yuwadee; Kamchonwongpaisan, Sumalee; Sirawaraporn, Worachart; Yuthavong, Yongyuth

    2015-09-01

    Interaction between antimalarial drugs is important in determining the outcome of chemotherapy using drug combinations. Inhibitors of dihydrofolate reductase (DHFR) such as pyrimethamine and of dihydropteroate synthase (DHPS) such as sulfa drugs are known to have synergistic interactions. However, studies of the synergism are complicated by the fact that the malaria parasite can also salvage exogenous folates, and the salvage may also be affected by the drugs. It is desirable to have a convenient system to study interaction of DHFR and DHPS inhibitors without such complications. Here, we describe the use of Escherichia coli transformed with malarial DHFR and DHPS, while its own corresponding genes have been inactivated by optimal concentration of trimethoprim and genetic knockout, respectively, to study the interaction of the inhibitors. Marked synergistic effects are observed for all combinations of pyrimethamine and sulfa inhibitors in the presence of trimethoprim. At 0.05μM trimethoprim, sum of fractional inhibitory concentrations, ΣFIC of pyrimethamine with sulfadoxine, pyrimethamine with sulfathiazole, pyrimethamine with sulfamethoxazole, and pyrimethamine with dapsone are in the range of 0.24-0.41. These results show synergism between inhibitors of the two enzymes even in the absence of folate transport and uptake. This bacterial surrogate system should be useful as a tool for assessing the interactions of drug combinations between the DHFR and DHPS inhibitors.

  14. In vitro evaluation of the cytotoxic and genotoxic effects of artemether, an antimalarial drug, in a gastric cancer cell line (PG100).

    PubMed

    Alcântara, Diego Di Felipe Ávila; Ribeiro, Helem Ferreira; Cardoso, Plínio Cerqueira Dos Santos; Araújo, Taíssa Maíra Thomaz; Burbano, Rommel Rodriguez; Guimarães, Adriana Costa; Khayat, André Salim; de Oliveira Bahia, Marcelo

    2013-02-01

    Artemisinin is a sesquiterpene lactone endoperoxide, obtained from Artemisia annua, and extensively used as an antimalarial drug. Many studies have reported the genotoxic and cytotoxic effects of artemisinins; however, there are no studies that compare such effects between cancer cell lines and normal human cells after treatment with artemether, an artemisinin derivative. Gastric cancer is the fourth most frequent type of cancer and the second highest cause of cancer mortality worldwide. Thus, the aim of this study was to evaluate the in vitro genotoxic and cytotoxic effects induced by artemether in gastric cancer cell line (PG100) and compare them with the results obtained in human lymphocytes exposed to the same conditions. We used MTT (3-(4,5-methylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide) assay, comet assay and ethidium bromide/acridine orange viability staining to evaluate the cytotoxic and genotoxic effects of artemether in PG100. MTT assay showed a decrease in the survival percentages for both cell types treated with different concentrations of artemether (P < 0.05). PG100 also showed a significant dose-dependent increase in DNA damage index at concentrations of 119.4 and 238.8 µg ml(-1) (P < 0.05). Our results showed that artemether induced necrosis in PG100 at concentrations of 238.8 and 477.6 µg ml(-1), for all the tested harvest times (P < 0.05). In lymphocytes, artemether induced both apoptosis and necrosis at concentrations of 238.8 and 477.6 µg ml(-1), for all the tested harvest times (P < 0.05). In conclusion, human lymphocytes were more sensitive to the cytotoxic effects of the antimalarial drug than the gastric cancer cell line PG100. PMID:21953315

  15. Traditionally-used antimalarials from the Meliaceae.

    PubMed

    Omar, S; Zhang, J; MacKinnon, S; Leaman, D; Durst, T; Philogene, B J R; Arnason, J T; Sanchez-Vindas, P E; Poveda, L; Tamez, P A; Pezzuto, J M

    2003-01-01

    A quantitative ethnobotanical approach to antimalarial drug discovery led to the identification of Lansium domesticum Corr. Ser. (Meliaceae) as an important antimalarial used by Kenyah Dyak healers in Indonesian Borneo. Triterpenoid lansiolides with antimalarial activity were isolated from the bark and shown to have activity in both in vitro bioassays with Plasmodium falciparum, and in mice infected with P. berghei. A survey of African and tropical American Meliaceae led to further development of the limonoid gedunin from the traditionally used medicinal plants, tropical cedar, Cedrela odorata L., and neem, Azadirachta indica A. Juss. Gedunin has significant in vitro activity but initially showed poor in vivo activity. In vivo activity was improved by (1) incorporation into an easy to absorb suspension, (2) preparation of a more stable compound, 7-methoxygedunin; and (3) synergism with dillapiol, a cytochrome P450 3A4 inhibitor. The results show the potential for both antimalarial drug and phytomedicine development from traditionally used plants. PMID:12570769

  16. Antimalarials in dermatology: mechanism of action, indications, and side effects.

    PubMed

    Rodriguez-Caruncho, C; Bielsa Marsol, I

    2014-04-01

    Antimalarial drugs have been in common use in dermatology since the 1950s. Their mechanism of action is complex, and it is now known that they act through various pathways. We review the indications for antimalarials in dermatology, their adverse effects, and some less well-known effects, such as their antithrombotic and hypolipidemic action. The most recent recommendations concerning ophthalmological screening in patients on antimalarials are also reviewed.

  17. Acridine and Acridinones: Old and New Structures with Antimalarial Activity

    PubMed Central

    Valdés, Aymé Fernández-Calienes

    2011-01-01

    Since emergence of chloroquine-resistant Plasmodium falciparum and reports of parasite resistance to alternative drugs, there has been renewed interest in the antimalarial activity of acridines and their congeners, the acridinones. This article presents literature compilation of natural acridinone alkaloids and synthetic 9-substituted acridines, acridinediones, haloalcoxyacridinones and 10-N-substituted acridinones with antimalarial activity. The review also provides an outlook to antimalarial modes of action of some described compounds. PMID:21673977

  18. Capillary electrophoresis methods for the analysis of antimalarials. Part I. Chiral separation methods.

    PubMed

    Amin, N'cho Christophe; Blanchin, Marie-Dominique; Aké, Michèle; Fabre, Huguette

    2012-11-16

    This paper presents an overview on the current status of enantiomeric and diastereomeric separations of chiral antimalarials and derivatives by capillary electrophoresis (CE). The wide variety of chiral selectors which have been employed to resolve successfully antimalarial enantiomers: oligosaccharides (cyclodextrins, oligomaltodextrins), neutral (amylose, dextrin and dextran) and charged (chondroitin sulfate, heparin, dextran sulfate) polysaccharides and proteins are reviewed. Cyclodextrins were the most employed. Chiral additives added to the background electrolyte often facilitated separations of quinine/quinidine and cinchonine/cinchonidine diastereomers. However, in a few cases, using micellar electrokinetic capillary chromatography or non aqueous CE, resolution of diastereomers could be achieved without additives. Quantitative applications of CE to the quality control of antimalarial drugs and their analysis in biological and food matrices are presented.

  19. Quinoline-based antimalarial hybrid compounds.

    PubMed

    Vandekerckhove, Stéphanie; D'hooghe, Matthias

    2015-08-15

    Quinoline-containing compounds, such as quinine and chloroquine, have a long-standing history as potent antimalarial agents. However, the increasing resistance of the Plasmodium parasite against these drugs and the lack of licensed malaria vaccines have forced chemists to develop synthetic strategies toward novel biologically active molecules. A strategy that has attracted considerable attention in current medicinal chemistry is based on the conjugation of two biologically active molecules into one hybrid compound. Since quinolines are considered to be privileged antimalarial building blocks, the synthesis of quinoline-containing antimalarial hybrids has been elaborated extensively in recent years. This review provides a literature overview of antimalarial hybrid molecules containing a quinoline core, covering publications between 2009 and 2014. PMID:25593097

  20. Fake anti-malarials: start with the facts.

    PubMed

    Kaur, Harparkash; Clarke, Siȃn; Lalani, Mirza; Phanouvong, Souly; Guérin, Philippe; McLoughlin, Andrew; Wilson, Benjamin K; Deats, Michael; Plançon, Aline; Hopkins, Heidi; Miranda, Debora; Schellenberg, David

    2016-02-13

    This meeting report presents the key findings and discussion points of a 1-day meeting entitled 'Fake anti-malarials: start with the facts' held on 28th May 2015, in Geneva, Switzerland, to disseminate the findings of the artemisinin combination therapy consortium's drug quality programme. The teams purchased over 10,000 samples, using representative sampling approaches, from six malaria endemic countries: Equatorial Guinea (Bioko Island), Cambodia, Ghana, Nigeria, Rwanda and Tanzania. Laboratory analyses of these samples showed that falsified anti-malarials (<8 %) were found in just two of the countries, whilst substandard artemisinin-based combinations were present in all six countries and, artemisinin-based monotherapy tablets are still available in some places despite the fact that the WHO has urged regulatory authorities in malaria-endemic countries to take measures to halt the production and marketing of these oral monotherapies since 2007. This report summarizes the presentations that reviewed the public health impact of falsified and substandard drugs, sampling strategies, techniques for drug quality analysis, approaches to strengthen health systems capacity for the surveillance of drug quality, and the ensuing discussion points from the dissemination meeting.

  1. High prevalence of pfdhfr-pfdhps triple mutations associated with anti-malarial drugs resistance in Plasmodium falciparum isolates seven years after the adoption of sulfadoxine-pyrimethamine in combination with artesunate as first-line treatment in Iran.

    PubMed

    Rouhani, Maryam; Zakeri, Sedigheh; Pirahmadi, Sakineh; Raeisi, Ahmad; Djadid, Navid Dinparast

    2015-04-01

    The spread of anti-malarial drug resistance will challenge any malaria control and elimination strategies, and routine monitoring of resistance-associated molecular markers of commonly used anti-malarial drugs is very important. Therefore, in the present investigation, the extent of mutations/haplotypes in dhfr and dhps genes of Plasmodium falciparum isolates (n=72) was analyzed seven years after the introduction of sulfadoxine-pyrimethamine (SP) plus artesunate (AS) as first-line anti-malarial treatment in Iran using PCR-RFLP methods. The results showed that the majority of the patients (97.2%) carried both 59R and 108N mutations in pure form with wild-type genotype at positions N51 and I164. Additionally, a significant increase (P<0.05) was observed in the frequency of R59N108/G437 haplotype (79.2%) during 2012-2014. This raise was because of the significant increase (P<0.05) in the frequency of 437G mutation (81.9%), which more likely was due to more availability of SP as anti-malarial drug for treatment of falciparum patients in these malaria-endemic areas of Iran. However, no quintuple mutations associated with treatment failure were detected. In conclusion, the present results along with in vivo assays suggest that seven years after the adoption of SP-AS as the first-line treatment in Iran, this drug remains efficacious for treatment of uncomplicated falciparum malaria, as a partner drug with AS in these malaria-endemic areas.

  2. Tyrosine kinase inhibitors: New class of antimalarials on the horizon?

    PubMed

    Pathak, Vrushali; Colah, Roshan; Ghosh, Kanjaksha

    2015-08-01

    Development of the antimalarial drug resistant strains has currently become a major public health challenge. There is an urgent need to develop new antimalarial drugs. Tyrosine kinase inhibitors (TKIs) are receiving increasing attention as anticancer therapy. It has revolutionarised the management of CML to say the least. TKIs are also increasingly being implicated in complicated but vital life cycle of malaria parasite. Hence we tested two commonly used but different classes of TKIs (imatinib and sorafenib) in-vitro for their antimalarial activity and possible synergistic activity with existing antimalarial drug. Antimalarial activity was tested with the help of modified WHO microtest technique in-vitro for five different Plasmodium falciparum laboratory strains (3D7, Dd2, 7G8, MRC2, PKL9). Imatinib and sorafenib showed a promising antimalarial activity with all the strains. These compounds caused dose dependent inhibition of parasite maturation. The isobologram analysis of the interactions of these TKIs with standard antimalarial drug, artesunate revealed distinct patterns of synergism, additivity and antagonism at different ratios. Imatinib showed worthwhile synergism with artesunate indicating imatinib and other tyrosine kinase inhibitors may have significant antimalarial activity and can be used in combination therapy. PMID:26142327

  3. Interventions to improve the use of antimalarials in south-east Asia: an overview.

    PubMed Central

    Gomes, M.; Wayling, S.; Pang, L.

    1998-01-01

    There are few drugs for malaria, and those which are available for use are subject to rapid development of resistance. Curiously, little effort has been made to improve drug use in malaria-endemic countries and to assess the benefits of such improvements. Advances can be made in public understanding of the value of ingesting a full regimen of antimalarials, in order to achieve complete cure, and in improving simple technologies (blister packaging) to achieve the same result. Better efforts can be made to reduce the availability of fake or substandard drugs in the marketplace. In this article, we describe the outcome of a concerted effort to improve drug compliance and drug quality in an area of multidrug resistance for malaria. These research efforts, guided by the Task Force for Improved Use of Antimalarials, characterized the problems in drug compliance in South-East Asia, and developed interventions to improve drug use in the various countries. Interventions involved drug packaging, public information campaigns, and assessments of drug quality. Results show that blister packaging worked best to improve drug compliance and that the increased cost of packaged medication did not limit its use. Drug quality was a major problem in unregulated countries and should be improved. PMID:9763718

  4. Development of transgenic Artemisia annua (Chinese wormwood) plants with an enhanced content of artemisinin, an effective anti-malarial drug, by hairpin-RNA-mediated gene silencing.

    PubMed

    Zhang, Ling; Jing, Fuyuan; Li, Fupeng; Li, Meiya; Wang, Yuliang; Wang, Guofeng; Sun, Xiaofen; Tang, Kexuan

    2009-03-01

    Artemisinin is an effective anti-malarial drug isolated from Artemisia annua L. (Chinese wormwood), but the content of artemisinin in A. annua is low. In the present study we explored the possibility of using genetic engineering to increase the artemisinin content of A. annua by suppressing the expression of SQS (squalene synthase), a key enzyme of sterol pathway (a pathway competitive with that of artemisinin biosynthesis) by means of a hairpin-RNA-mediated RNAi (RNA interference) technique. A total of 23 independent transgenic A. annua plants were obtained through Agrobacterium tumefaciens-mediated transformation, which was confirmed by PCR and Southern-blot analyses. HPLC-evaporative light-scattering detection analysis showed that the artemisinin content of some transgenic plants was significantly increased, with the highest values reaching 31.4 mg/g dry weight, which is about 3.14-fold the content observed in untransformed control plants. Real-time reverse transcription-PCR analysis demonstrated that the expression of SQS was suppressed significantly, and GC-MS analysis showed that sterol was efficiently decreased in the transgenic plants. The present study demonstrated that genetic-engineering strategy of RNAi is an effective means of increasing artemisinin content in plants.

  5. Structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase in a quaternary complex with a magnesium ion, NADPH and the antimalarial drug fosmidomycin

    SciTech Connect

    Yajima, Shunsuke Hara, Kodai; Iino, Daisuke; Sasaki, Yasuyuki; Kuzuyama, Tomohisa; Ohsawa, Kanju; Seto, Haruo

    2007-06-01

    The crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) from Escherichia coli complexed with Mg{sup 2+}, NADPH and fosmidomycin was determined at 2.2 Å resolution. The structure showed a well defined loop conformation at the active site of DXR. The crystal structure of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) from Escherichia coli complexed with Mg{sup 2+}, NADPH and fosmidomycin was solved at 2.2 Å resolution. DXR is the key enzyme in the 2-C-methyl-d-erythritol 4-phosphate pathway and is an effective target of antimalarial drugs such as fosmidomycin. In the crystal structure, electron density for the flexible loop covering the active site was clearly observed, indicating the well ordered conformation of DXR upon substrate binding. On the other hand, no electron density was observed for the nicotinamide-ribose portion of NADPH and the position of Asp149 anchoring Mg{sup 2+} was shifted by NADPH in the active site.

  6. [Animal drugs quality status and reason analysis].

    PubMed

    Ding, Qing; Qiu, Ya-jing; Fang, Ke-hui; Hu, Hao-bin; Wu, Yue

    2015-11-01

    In order to reaction the quality present situation, problems on the current quality of animal sources of drugs are summed up by using test data analysis, literature search and marketing research. This paper can also help the improvement of the quality management, the revision of the relevant department policy system and the improvement of standards.

  7. Antimalarial drug interactions of compounds isolated from Kigelia africana (Bignoniaceae) and their synergism with artemether, against the multidrug-resistant W2mef Plasmodium falciparum strain.

    PubMed

    Zofou, Denis; Tene, Mathieu; Tane, Pierre; Titanji, Vincent P K

    2012-02-01

    For decades, drug resistance has been the major obstacle in the fight against malaria, and the search for new drugs together with the combination therapy constitutes the major approach in responding to this situation. The present study aims at assessing the in vitro antimalarial activity of four compounds isolated from Kigelia africana stem bark (atranorin - KAE1, specicoside - KAE7, 2β,3β,19α-trihydroxy-urs-12-20-en-28-oic acid - KAE3, and p-hydroxy-cinnamic acid - KAE10) and their drug interactions among themselves and their combination effects with quinine and artemether. The antiplasmodial activity and drug interactions were evaluated against the multidrug-resistant W2mef strain of Plasmodium falciparum using the parasite lactate dehydrogenase assay. Three of the four compounds tested were significantly active against W2mef: specicoside (IC(50) = 1.02 ± 0.17 μM), 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid (IC(50) = 1.86 ± 0.15 μM) and atranorin (IC(50) = 1.78 ± 0.18 μM), whereas p-hydroxy-cinnamic acid showed a weak activity (IC(50) = 12.89 ± 0.87 μM). A slight synergistic effect was observed between atranorin and 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid (Combination index, CI = 0.82) whereas the interaction between specicoside and p-hydroxy-cinnamic acid were instead antagonistic (CI = 2.67). All the three compounds showed synergistic effects with artemether, unlike the slight antagonistic interactions of atranorin and 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid in combination with quinine. K. africana compounds are therefore likely to serve as leads in the development of new partner drugs in artemether-based combination therapy. PMID:21814840

  8. Immunoliposome-mediated drug delivery to Plasmodium-infected and non-infected red blood cells as a dual therapeutic/prophylactic antimalarial strategy.

    PubMed

    Moles, Ernest; Urbán, Patricia; Jiménez-Díaz, María Belén; Viera-Morilla, Sara; Angulo-Barturen, Iñigo; Busquets, Maria Antònia; Fernàndez-Busquets, Xavier

    2015-07-28

    One of the most important factors behind resistance evolution in malaria is the failure to deliver sufficiently high amounts of drugs to early stages of Plasmodium-infected red blood cells (pRBCs). Despite having been considered for decades as a promising approach, the delivery of antimalarials encapsulated in immunoliposomes targeted to pRBCs has not progressed towards clinical applications, whereas in vitro assays rarely reach drug efficacy improvements above 10-fold. Here we show that encapsulation efficiencies reaching >96% are achieved for the weak basic drugs chloroquine (CQ) and primaquine using the pH gradient loading method in liposomes containing neutral saturated phospholipids. Targeting antibodies are best conjugated through their primary amino groups, adjusting chemical crosslinker concentration to retain significant antigen recognition. Antigens from non-parasitized RBCs have also been considered as targets for the delivery to the cell of drugs not affecting the erythrocytic metabolism. Using this strategy, we have achieved unprecedented complete nanocarrier targeting to early intraerythrocytic stages of the malaria parasite for which there is a lack of specific extracellular molecular tags. Immunoliposomes studded with monoclonal antibodies raised against the erythrocyte surface protein glycophorin A were capable of targeting 100% RBCs and pRBCs at the low concentration of 0.5μM total lipid in the culture, with >95% of added liposomes retained on cell surfaces. When exposed for only 15min to Plasmodium falciparum in vitro cultures of early stages, free CQ had no significant effect on the viability of the parasite up to 200nM, whereas immunoliposomal 50nM CQ completely arrested its growth. In vivo assays in mice showed that immunoliposomes cleared the pathogen below detectable levels at a CQ dose of 0.5mg/kg, whereas free CQ administered at 1.75mg/kg was, at most, 40-fold less efficient. Our data suggest that this significant improvement is in part

  9. Antimalarial Activity of Cupredoxins

    PubMed Central

    Cruz-Gallardo, Isabel; Díaz-Moreno, Irene; Díaz-Quintana, Antonio; Donaire, Antonio; Velázquez-Campoy, Adrián; Curd, Rachel D.; Rangachari, Kaveri; Birdsall, Berry; Ramos, Andres; Holder, Anthony A.; De la Rosa, Miguel A.

    2013-01-01

    The discovery of effective new antimalarial agents is urgently needed. One of the most frequently studied molecules anchored to the parasite surface is the merozoite surface protein-1 (MSP1). At red blood cell invasion MSP1 is proteolytically processed, and the 19-kDa C-terminal fragment (MSP119) remains on the surface and is taken into the red blood cell, where it is transferred to the food vacuole and persists until the end of the intracellular cycle. Because a number of specific antibodies inhibit erythrocyte invasion and parasite growth, MSP119 is therefore a promising target against malaria. Given the structural homology of cupredoxins with the Fab domain of monoclonal antibodies, an approach combining NMR and isothermal titration calorimetry (ITC) measurements with docking calculations based on BiGGER is employed on MSP119-cupredoxin complexes. Among the cupredoxins tested, rusticyanin forms a well defined complex with MSP119 at a site that overlaps with the surface recognized by the inhibitory antibodies. The addition of holo-rusticyanin to infected cells results in parasitemia inhibition, but negligible effects on parasite growth can be observed for apo-rusticyanin and other proteins of the cupredoxin family. These findings point to rusticyanin as an excellent therapeutic tool for malaria treatment and provide valuable information for drug design. PMID:23749994

  10. Repurposing the anti-malarial drug artesunate as a novel therapeutic agent for metastatic renal cell carcinoma due to its attenuation of tumor growth, metastasis, and angiogenesis

    PubMed Central

    Lim, Sharon; Lee, Se Jeong; Lim, Joung Eun; Nam, Do-Hyun; Joo, Kyeung Min; Jeong, Byong Chang; Jeon, Seong Soo; Choi, Han Yong; Lee, Hye Won

    2015-01-01

    Despite advances in the development of molecularly targeted therapies, metastatic renal cell carcinoma (RCC) is still incurable. Artesunate (ART), a well-known anti-malarial drug with low toxicity, exhibits highly selective anti-tumor actions against various tumors through generation of cytotoxic carbon-centered free radical in the presence of free iron. However, the therapeutic efficacy of ART against metastatic RCC has not yet been fully elucidated. In the analysis on a dataset from The Cancer Genome Atlas (TCGA) (n = 469) and a tissue microarray set from Samsung Medical Center (n = 119) from a cohort of patients with clear cell RCC (ccRCC), up-regulation of transferrin receptor 1 (TfR1), which is a well-known predictive marker for ART, was correlated with the presence of distant metastasis and an unfavorable prognosis. Moreover, ART exerted potent selective cytotoxicity against human RCC cell lines (Caki-1, 786-O, and SN12C-GFP-SRLu2) and sensitized these cells to sorafenib in vitro, and the extent of ART cytotoxicity correlated with TfR1 expression. ART-mediated growth inhibition of human RCC cell lines was shown to result from the induction of cell cycle arrest at the G2/M phase and oncosis-like cell death. Furthermore, ART inhibited cell clonogenicity and invasion of human RCC cells and anti-angiogenic effects in vitro in a dose-dependent manner. Consistent with these in vitro data, anti-tumor, anti-metastatic and anti-angiogenic effects of ART were also validated in human 786-O xenografts. Taken together, ART is a promising novel candidate for treating human RCC, either alone or in combination with other therapies. PMID:26426994

  11. Methodological Issues in the Assessment of Antimalarial Drug Treatment: Analysis of 13 Studies in Eight African Countries from 2001 to 2004▿

    PubMed Central

    Guthmann, Jean-Paul ; Pinoges, Loretxu; Checchi, Francesco; Cousens, Simon; Balkan, Suna; van Herp, Michel ; Legros, Dominique; Olliaro, Piero

    2006-01-01

    The objectives of these analyses were to assess the feasibility of the latest WHO recommendations (28-day follow-up with PCR genotyping) for the assessment of antimalarial drug efficacy in vivo and to examine how different statistical approaches affect results. We used individual-patient data from 13 studies of uncomplicated pediatric falciparum malaria conducted in sub-Saharan Africa, using chloroquine (CQ), sulfadoxine/pyrimethamine (SP), or amodiaquine (AQ). We assessed the use effectiveness and test performance of PCR genotyping in distinguishing recurrent infections. In analyzing data, we compared (i) the risk of failure on target days (days 14 and 28) by using Kaplan-Meier and per-protocol evaluable patient analyses, (ii) PCR-corrected results allowing (method 1) or excluding (method 2) new infections, (iii) and day 14 versus day 28 results. Of the 2,576 patients treated, 2,287 (89%) were evaluable on day 28. Of the 695 recurrences occurring post-day 14, 650 could be processed and 584 were resolved (PCR use effectiveness, 84%; test performance, 90%). The risks of failure on day 28 with Kaplan-Meier and evaluable-patient analyses tended to be generally close (except in smaller studies) because the numbers of dropouts were minimal, but attrition rates on day 28 were higher with the latter method. Method 2 yielded higher risks of failure than method 1. Extending observation to 28 days produced higher estimated risks of failure for SP and AQ but not for CQ (high failure rates by day 14). Results support the implementation of the current WHO protocol and favor analyzing PCR-corrected outcomes by Kaplan-Meier analysis (which allows for dropouts) and retaining new infections (which minimizes losses). PMID:16954313

  12. Oral treatments of Echinococcus multilocularis-infected mice with the antimalarial drug mefloquine that potentially interacts with parasite ferritin and cystatin.

    PubMed

    Küster, Tatiana; Stadelmann, Britta; Rufener, Reto; Risch, Corina; Müller, Joachim; Hemphill, Andrew

    2015-11-01

    This study investigated the effects of oral treatments of Echinococcus multilocularis-infected mice with the antimalarial drug mefloquine (MEF) and identified proteins that bind to MEF in parasite extracts and human cells by affinity chromatography. In a pilot experiment, MEF treatment was applied 5 days per week and was intensified by increasing the dosage stepwise from 12.5 mg/kg to 200 mg/kg during 4 weeks followed by treatments of 100 mg/kg during the last 7 weeks. This resulted in a highly significant reduction of parasite weight in MEF-treated mice compared with mock-treated mice, but the reduction was significantly less efficacious compared with the standard treatment regimen of albendazole (ABZ). In a second experiment, MEF was applied orally in three different treatment groups at dosages of 25, 50 or 100 mg/kg, but only twice a week, for a period of 12 weeks. Treatment at 100 mg/kg had a profound impact on the parasite, similar to ABZ treatment at 200 mg/kg/day (5 days/week for 12 weeks). No adverse side effects were noted. To identify proteins in E. multilocularis metacestodes that physically interact with MEF, affinity chromatography of metacestode extracts was performed on MEF coupled to epoxy-activated Sepharose(®), followed by SDS-PAGE and in-gel digestion LC-MS/MS. This resulted in the identification of E. multilocularis ferritin and cystatin as MEF-binding proteins. In contrast, when human cells were exposed to MEF affinity chromatography, nicotinamide phosphoribosyltransferase was identified as a MEF-binding protein. This indicates that MEF could potentially interact with different proteins in parasites and human cells. PMID:26395219

  13. Investigations of the effects of the antimalarial drug dihydroartemisinin (DHA) using the Frog Embryo Teratogenesis Assay-Xenopus (FETAX).

    PubMed

    Longo, Monica; Zanoncelli, Sara; Della Torre, Paola; Rosa, Francesco; Giusti, AnnaMaria; Colombo, Paolo; Brughera, Marco; Mazué, Guy; Olliaro, Piero

    2008-08-01

    Artemisinin derivatives are effective and safe drugs for treating malaria, but they are not recommended during the first trimester of pregnancy because of resorptions and abnormalities observed in animal reproduction studies. Previous studies in rats showed that artemisinin embryotoxicity derives from the depletion of primitive red blood cells (RBCs) over a narrow critical time window (gestation Days 9-14). In order to further investigate the susceptibility of primitive RBCs to artemisinins and to establish whether this susceptibility is species-specific or inherent to the compound, we studied dihydroartemisinin (DHA), both a drug in its own right and the main metabolite of current artemisinin derivatives in use, in the Frog Embryo Teratogenesis Assay-Xenopus (FETAX). This model readily allows investigation and monitoring of primitive and definitive RBCs. Effects on frog larvae exposed to DHA for 48 h during early embryonic development, starting from 24 h post fertilization, were similar to those on rat embryos in terms of reduction in the number of primitive RBCs (clonally produced within the ventral blood island). In contrast, RBCs of older larvae (stage 47, produced at the definitive sites of hematopoiesis) were affected minimally and subsequently recovered. Compared to rat embryos, the frog larvae had no areas of necrosis but they shared similar heart defects. The mitochondrion appeared to be the main subcellular target, similar to observations in Plasmodium. These results implicate artemisinin-induced embryotoxicity through perturbation of metabolically active RBCs; whereas this mode of action does not appear to be species-specific, the stages of susceptibility varied between different species. The window of susceptibility and duration of exposure must be considered to evaluate the clinical relevance of these findings. PMID:18394862

  14. A combined within-host and between-hosts modelling framework for the evolution of resistance to antimalarial drugs

    PubMed Central

    2016-01-01

    The spread of drug resistance represents a significant challenge to many disease control efforts. The evolution of resistance is a complex process influenced by transmission dynamics between hosts as well as infection dynamics within these hosts. This study aims to investigate how these two processes combine to impact the evolution of resistance in malaria parasites. We introduce a stochastic modelling framework combining an epidemiological model of Plasmodium transmission and an explicit within-human infection model for two competing strains. Immunity, treatment and resistance costs are included in the within-host model. We show that the spread of resistance is generally less likely in areas of intense transmission, and therefore of increased competition between strains, an effect exacerbated when costs of resistance are higher. We also illustrate how treatment influences the spread of resistance, with a trade-off between slowing resistance and curbing disease incidence. We show that treatment coverage has a stronger impact on disease prevalence, whereas treatment efficacy primarily affects resistance spread, suggesting that coverage should constitute the primary focus of control efforts. Finally, we illustrate the importance of feedbacks between modelling scales. Overall, our results underline the importance of concomitantly modelling the evolution of resistance within and between hosts. PMID:27075004

  15. A combined within-host and between-hosts modelling framework for the evolution of resistance to antimalarial drugs.

    PubMed

    Legros, Mathieu; Bonhoeffer, Sebastian

    2016-04-01

    The spread of drug resistance represents a significant challenge to many disease control efforts. The evolution of resistance is a complex process influenced by transmission dynamics between hosts as well as infection dynamics within these hosts. This study aims to investigate how these two processes combine to impact the evolution of resistance in malaria parasites. We introduce a stochastic modelling framework combining an epidemiological model of Plasmodium transmission and an explicit within-human infection model for two competing strains. Immunity, treatment and resistance costs are included in the within-host model. We show that the spread of resistance is generally less likely in areas of intense transmission, and therefore of increased competition between strains, an effect exacerbated when costs of resistance are higher. We also illustrate how treatment influences the spread of resistance, with a trade-off between slowing resistance and curbing disease incidence. We show that treatment coverage has a stronger impact on disease prevalence, whereas treatment efficacy primarily affects resistance spread, suggesting that coverage should constitute the primary focus of control efforts. Finally, we illustrate the importance of feedbacks between modelling scales. Overall, our results underline the importance of concomitantly modelling the evolution of resistance within and between hosts. PMID:27075004

  16. Counterfeit and Substandard Antimalarial Drugs

    MedlinePlus

    ... a CDC Malaria Branch clinician. malaria@cdc.gov File Formats Help: How do I view different file formats (PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word file Microsoft Excel ...

  17. In Silico Mining for Antimalarial Structure-Activity Knowledge and Discovery of Novel Antimalarial Curcuminoids.

    PubMed

    Viira, Birgit; Gendron, Thibault; Lanfranchi, Don Antoine; Cojean, Sandrine; Horvath, Dragos; Marcou, Gilles; Varnek, Alexandre; Maes, Louis; Maran, Uko; Loiseau, Philippe M; Davioud-Charvet, Elisabeth

    2016-01-01

    Malaria is a parasitic tropical disease that kills around 600,000 patients every year. The emergence of resistant Plasmodium falciparum parasites to artemisinin-based combination therapies (ACTs) represents a significant public health threat, indicating the urgent need for new effective compounds to reverse ACT resistance and cure the disease. For this, extensive curation and homogenization of experimental anti-Plasmodium screening data from both in-house and ChEMBL sources were conducted. As a result, a coherent strategy was established that allowed compiling coherent training sets that associate compound structures to the respective antimalarial activity measurements. Seventeen of these training sets led to the successful generation of classification models discriminating whether a compound has a significant probability to be active under the specific conditions of the antimalarial test associated with each set. These models were used in consensus prediction of the most likely active from a series of curcuminoids available in-house. Positive predictions together with a few predicted as inactive were then submitted to experimental in vitro antimalarial testing. A large majority from predicted compounds showed antimalarial activity, but not those predicted as inactive, thus experimentally validating the in silico screening approach. The herein proposed consensus machine learning approach showed its potential to reduce the cost and duration of antimalarial drug discovery. PMID:27367660

  18. In Silico Mining for Antimalarial Structure-Activity Knowledge and Discovery of Novel Antimalarial Curcuminoids.

    PubMed

    Viira, Birgit; Gendron, Thibault; Lanfranchi, Don Antoine; Cojean, Sandrine; Horvath, Dragos; Marcou, Gilles; Varnek, Alexandre; Maes, Louis; Maran, Uko; Loiseau, Philippe M; Davioud-Charvet, Elisabeth

    2016-06-29

    Malaria is a parasitic tropical disease that kills around 600,000 patients every year. The emergence of resistant Plasmodium falciparum parasites to artemisinin-based combination therapies (ACTs) represents a significant public health threat, indicating the urgent need for new effective compounds to reverse ACT resistance and cure the disease. For this, extensive curation and homogenization of experimental anti-Plasmodium screening data from both in-house and ChEMBL sources were conducted. As a result, a coherent strategy was established that allowed compiling coherent training sets that associate compound structures to the respective antimalarial activity measurements. Seventeen of these training sets led to the successful generation of classification models discriminating whether a compound has a significant probability to be active under the specific conditions of the antimalarial test associated with each set. These models were used in consensus prediction of the most likely active from a series of curcuminoids available in-house. Positive predictions together with a few predicted as inactive were then submitted to experimental in vitro antimalarial testing. A large majority from predicted compounds showed antimalarial activity, but not those predicted as inactive, thus experimentally validating the in silico screening approach. The herein proposed consensus machine learning approach showed its potential to reduce the cost and duration of antimalarial drug discovery.

  19. Psychoactive drugs and quality of life.

    PubMed

    Ventegodt, Søren; Merrick, Joav

    2003-08-18

    This study was performed on a representative sample of the Danish population in order to investigate the connection to the use of psychoactive drugs and quality of life (QOL) by way of a questionnaire-based survey. The questionnaire was mailed in February 1993 to 2,460 persons aged between 18 and 88, randomly selected from the CPR (Danish Central Register), and 7,222 persons from the Copenhagen Perinatal Birth Cohort 1959-61. A total of 1,501 persons between the ages 18 and 88 years and 4,626 persons between the ages 31 and 33 years returned the questionnaire (response rates of 61.0% and 64.1%, respectively). Variables investigated in this study were ten different psychotropic drugs and quality of life. Our study showed that over half the Danish population had used illegal psychotropic drugs. The most commonly used was cannabis (marijuana) though experience of this drug appeared not to co-vary with QOL to any significant extent. Cocaine, amphetamine, and psilocybin had been used by 1.2 to 3.3% of the population and this varied with QOL to a clear albeit small extent. LSD has been used by 1.2% of the population and the users had a QOL score 10% lower than those who had never used psychotropic drugs. The group with the lowest quality of life was found to be persons who had used heroin, morphine, methadone, and a mixture of alcohol and tranquilizers (10-20% below the group with the highest quality of life).

  20. A “reverse pharmacology” approach for developing an anti-malarial phytomedicine

    PubMed Central

    2011-01-01

    A “reverse pharmacology” approach to developing an anti-malarial phytomedicine was designed and implemented in Mali, resulting in a new standardized herbal anti-malarial after six years of research. The first step was to select a remedy for development, through a retrospective treatment-outcome study. The second step was a dose-escalating clinical trial that showed a dose-response phenomenon and helped select the safest and most efficacious dose. The third step was a randomized controlled trial to compare the phytomedicine to the standard first-line treatment. The last step was to identify active compounds which can be used as markers for standardization and quality control. This example of “reverse pharmacology” shows that a standardized phytomedicine can be developed faster and more cheaply than conventional drugs. Even if both approaches are not fully comparable, their efficiency in terms of public health and their complementarity should be thoroughly considered. PMID:21411019

  1. 78 FR 31943 - Draft Guidance for Industry on Contract Manufacturing Arrangements for Drugs: Quality Agreements...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-28

    ... Arrangements for Drugs: Quality Agreements; Availability AGENCY: Food and Drug Administration, HHS. ACTION... guidance for industry entitled ``Contract Manufacturing Arrangements for Drugs: Quality Agreements.'' This... drugs can utilize Quality Agreements to delineate their responsibilities and assure drug quality,...

  2. Antimalarial properties of imipramine and amitriptyline

    SciTech Connect

    Dutta, P.; Siegel, L.; Pinto, J.; Meshnick, S.

    1986-03-01

    This laboratory has previously demonstrated that imipramine (IM) and amitriptyline (AM), inhibit the conversion of riboflavin to its coenzymic derivatives. Several other laboratories have shown that dietary riboflavin deficiency is protective against malarial infection. In the present investigation, the authors determined whether IM and AM exert antimalarial effects similar to that of riboflavin deficiency, as they have hypothesized. In addition, they evaluated whether these drugs, like other antimalarial agents, increase the hemolytic response to ferriprotoporphyrin IX (FP). The growth of P. falciparum (FCR3) in the absence or presence of these drugs (80 ..mu..M) was measured by incubating parasitized erythrocytes for 48 h in RPMI 1640 medium. Parasitemia was determined by counting erythrocyte smears and monitoring (/sup 3/H)hypoxanthine uptake. With no drug, parasitemia was 20.3 +/- 5.3%, whereas in the presence of IM and AM, parasitemia was reduced to 7.3 +/- 0.8% and 13.6 +/- 2.8%, respectively. The uptake of (/sup 3/H)hypoxanthine was reduced to 47 +/- 3.6% and 54 +/- 2.9% of control by IM and AM, respectively. Assays of hemolysis were conducted by incubating 0.5% RBC suspension in NaCl-Tris buffer for 3 h at 37/sup 0/C with variable concentrations of drugs and/or FP (1-7 ..mu..M). Both drugs at 10 to 100 ..mu..M significantly enhanced hemolysis induced by FP. No hemolysis by these drugs was detected in the absence of FP. It is concluded that the tricyclic antidepressants, IM and AM, possess substantial antimalarial properties, thereby supporting the hypothesis that drugs which interfere with riboflavin metabolism should also provide protection against malaria.

  3. [Historical overview of antimalarials used in Venezuela].

    PubMed

    Zerpa de Artiles, N

    1993-06-01

    A historical review of antimalarials used in Venezuela is presented from the time when the bark of quina was used until the massive distribution of quinine and metoquine by the Dirección de Malariología y Saneamiento Ambiental. The utility of chloroquine and primaquine against sensible parasite isolates and of sulfadoxine-pyrimethamine and quinine, currently used against P. falciparum resistant strains, is thoroughly discussed. The author suggests use of artemisimine and its derivatives as a very promising antimalarial drug. She also stresses the possibility of the application of new antimalaria vaccine against P. falciparum blood states, presently assayed in the country as an additional tool in malaria control programs. PMID:11640680

  4. [Historical overview of antimalarials used in Venezuela].

    PubMed

    Zerpa de Artiles, N

    1993-06-01

    A historical review of antimalarials used in Venezuela is presented from the time when the bark of quina was used until the massive distribution of quinine and metoquine by the Dirección de Malariología y Saneamiento Ambiental. The utility of chloroquine and primaquine against sensible parasite isolates and of sulfadoxine-pyrimethamine and quinine, currently used against P. falciparum resistant strains, is thoroughly discussed. The author suggests use of artemisimine and its derivatives as a very promising antimalarial drug. She also stresses the possibility of the application of new antimalaria vaccine against P. falciparum blood states, presently assayed in the country as an additional tool in malaria control programs.

  5. Antimalarial pharmacology and therapeutics of atovaquone

    PubMed Central

    Nixon, Gemma L.; Moss, Darren M.; Shone, Alison E.; Lalloo, David G.; Fisher, Nicholas; O'Neill, Paul M.; Ward, Stephen A.; Biagini, Giancarlo A.

    2013-01-01

    Atovaquone is used as a fixed-dose combination with proguanil (Malarone) for treating children and adults with uncomplicated malaria or as chemoprophylaxis for preventing malaria in travellers. Indeed, in the USA, between 2009 and 2011, Malarone prescriptions accounted for 70% of all antimalarial pre-travel prescriptions. In 2013 the patent for Malarone will expire, potentially resulting in a wave of low-cost generics. Furthermore, the malaria scientific community has a number of antimalarial quinolones with a related pharmacophore to atovaquone at various stages of pre-clinical development. With this in mind, it is timely here to review the current knowledge of atovaquone, with the purpose of aiding the decision making of clinicians and drug developers involved in the future use of atovaquone generics or atovaquone derivatives. PMID:23292347

  6. Chitosan-based nanocarriers for antimalarials

    NASA Astrophysics Data System (ADS)

    Dreve, Simina; Kacso, Iren; Popa, Adriana; Raita, Oana; Bende, A.; Borodi, Gh.; Bratu, I.

    2012-02-01

    The objective of this research was to synthesize and characterize chitosan-based liquid and solid materials with unique absorptive and mechanical properties as carriers for quinine - one of the most used antimalarial drug. The use of chitosan (CTS) as base in polyelectrolyte complex systems, to prepare solid release systems as sponges is presented. The preparation by double emulsification of CTS hydrogels carrying quinine as anti-malarial drug is reported. The concentration of quinine in the CTS hydrogel was 0.08 mmol. Chitosan - drug loaded hydrogel was used to generate solid sponges by freeze-drying at -610°C and 0.09 atm. Structural investigations of the solid formulations were done by Fourier-transformed infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-VIS), spectrofluorimetry, differential scanning calorimetry (DSC) and X-ray diffractometry. The results indicated that the drug molecule is forming temporary chelates in CTS hydrogels and sponges. Electron paramagnetic resonance (EPR) demonstrates the presence of free radicals in a wide range and the antioxidant activity for chitosan - drug supramolecular cross-linked assemblies.

  7. Antimalarial plants of northeast India: An overview

    PubMed Central

    Shankar, Rama; Deb, Sourabh; Sharma, B K

    2012-01-01

    The need for an alternative drug for malaria initiated intensive efforts for developing new antimalarials from indigenous plants. The information from different tribal communities of northeast India along with research papers, including books, journals and documents of different universities and institutes of northeast India was collected for information on botanical therapies and plant species used for malaria. Sixty-eight plant species belonging to 33 families are used by the people of northeast India for the treatment of malaria. Six plant species, namely, Alstonia scholaris, Coptis teeta, Crotolaria occulta, Ocimum sanctum, Polygala persicariaefolia, Vitex peduncularis, have been reported by more than one worker from different parts of northeast India. The species reported to be used for the treatment of malaria were either found around the vicinity of their habitation or in the forest area of northeast India. The most frequently used plant parts were leaves (33%), roots (31%), and bark and whole plant (12%). The present study has compiled and enlisted the antimalarial plants of northeast India, which would help future workers to find out the suitable antimalarial plants by thorough study. PMID:22529674

  8. Antimalarial activity of cedronin.

    PubMed

    Moretti, C; Deharo, E; Sauvain, M; Jardel, C; David, P T; Gasquet, M

    1994-06-01

    Cedronin was isolated from Simaba cedron Planchon (Simaroubaceae), a species popularly believed in South America to have antimalarial properties. It was examined for in vitro and in vivo antimalarial activities and for cytotoxicity against KB cells. Experimental results showed that cedronin was active against chloroquine-sensitive and resistant strain, with an IC50 of 0.25 micrograms/ml (0.65 mumol/ml). It was also found to be active in vivo against Plasmodium vinkei with an IC50 of 1.8 mg/kg (4.7 nM/kg) in the classic 4-day test. Cedronin belongs to the small group of quassinoids with a C19 basic skeleton and shows a rather low cytotoxicity against KB cells (IC50 = 4 micrograms/ml, 10.4 microM) as compared with C20 biologically active quassinoids; however its toxic/therapeutic ratio (10/1.8) remains lower than chloroquine (10/0.5).

  9. Reliable low-cost capillary electrophoresis device for drug quality control and counterfeit medicines.

    PubMed

    Marini, R D; Rozet, E; Montes, M L A; Rohrbasser, C; Roht, S; Rhème, D; Bonnabry, P; Schappler, J; Veuthey, J-L; Hubert, Ph; Rudaz, S

    2010-12-15

    The proportion of counterfeit medicines is dramatically increasing these last few years. According to numerous official sources, in some pharmaceutical wholesalers in African countries, the proportion has reached 80%. Unfortunately, this situation is far to be improved due to lack of suitable analytical equipment allowing rapid actions of the Regulatory Agencies based on scientific consideration, at affordable cost and all over the drug supply chain. For that purpose, a network group considered that mater by building a low-cost original capillary electrophoresis (CE) equipment equipped with a new deep UV detector based on LED technology. The generic conditions for analysis were investigated: capillary zone electrophoresis (CZE) performed at acidic pH for basic drug molecules (i.e., quinine, highly used as the last antimalarial rampart), basic pH for compounds such as furosemide (a common diuretic drug) and at neutral pH for a well known antibiotic combination, trimethoprim/sulfamethoxazol. To evaluate the ability of the CE equipment for quantification, a full validation and a method comparison study were carried out for the CZE method dedicated to quinine determination. The validation involved the use of accuracy profile and total error concept to monitor the adequacy of the results obtained by the new prototype. The method comparison was based on the Bland and Altman approach by comparing results obtained by the low-cost CE and a conventional set-up. Subsequent validation studies were realized with neutral and acidic drug molecules, each focusing on a single concentration level calibration curve in order to maintain as low as possible the expenses due to reagents and thus the cost of analysis, as important advantages of CE for drug quality control. PMID:20719445

  10. Antimalarial properties of SAABMAL®: an ethnomedicinal polyherbal formulation for the treatment of uncomplicated malaria infection in the tropics

    PubMed Central

    Obidike, I.C.; Amodu, B.; Emeje, M.O.

    2015-01-01

    Background & objectives: Malaria is a serious problem in the countries of the developing world. As the malaria parasite has become resistant to most of the antimalaria drugs available currently, there is a need to search for newer drugs. This study reports the pharmaceutical quality and in vivo antimalarial activities of a polyherbal formulation (SAABMAL®) used as malarial remedy in Nigeria. Methods: The antiplasmodial activity of SAABMAL® was determined by using the 4-day suppressive test in Plasmodium berghei-infected mice. The formulation was tried on three different experimental animal models for in vivo antimalarial activities, which are prophylactic, suppressive and curative in mice. Chloroquine and pyrimethamine were used as standard drugs for comparison. Results: The suppressive study showed that, SAABMAL® (200 and 400 mg/kg/bw) significantly (P<0.01) produced a suppression (29.39 - 100%) of parasitaemia in a dose-dependent manner, while the curative study showed that SAABMAL® at 400 mg significantly (P<0.01) reduced (95.80%) parasitaemia compared with controls. The mean survival time of SAABMAL®-treated groups (100 and 200 mg/kg) was higher than that of the chloroquine-treated group. Histopathologically, no changes were found in the spleen of both untreated and treated groups. SAABMAL® capsules were of good mechanical properties with low weight variation and high degree of content mass uniformity. Interpretation & conclusions: The results obtained in this study showed the efficacy of SAABMAL®, a herbal antimalarial formulation against chloroquine sensitive malaria and its potential use in the treatment of uncomplicated malaria infection. Further studies need to be done in humans to test its efficacy and safety for its potential use as an antimalarial drug. PMID:25900958

  11. On the molecular basis of the activity of the antimalarial drug chloroquine: EXAFS-assisted DFT evidence of a direct Fe-N bond with free heme in solution

    NASA Astrophysics Data System (ADS)

    Macetti, Giovanni; Rizzato, Silvia; Beghi, Fabio; Silvestrini, Lucia; Lo Presti, Leonardo

    2016-02-01

    4-aminoquinoline antiplasmodials interfere with the biocrystallization of the malaria pigment, a key step of the malaria parasite metabolism. It is commonly believed that these drugs set stacking π···π interactions with the Fe-protoporphyrin scaffold of the free heme, even though the details of the heme:drug recognition process remain elusive. In this work, the local coordination of Fe(III) ions in acidic solutions of hematin at room temperature was investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy in the 4.0-5.5 pH range, both in the presence and in the absence of the antimalarial drug chloroquine. EXAFS results were complemented by DFT simulations in polarizable continuum media to model solvent effects. We found evidence that a complex where the drug quinoline nitrogen is coordinated with the iron center might coexist with formerly proposed adduct geometries, based on stacking interactions. Charge-assisted hydrogen bonds among lateral chains of the two molecules play a crucial role in stabilizing this complex, whose formation is favored by the presence of lipid micelles. The direct Fe-N bond could reversibly block the axial position in the Fe 1st coordination shell in free heme, acting as an inhibitor for the crystallization of the malaria pigment without permanently hampering the catalytic activity of the redox center. These findings are discussed in the light of possible implications on the engineering of drugs able to thwart the adaptability of the malaria parasite against classical aminoquinoline-based therapies.

  12. Rapid and Specific Drug Quality Testing Assay for Artemisinin and Its Derivatives Using a Luminescent Reaction and Novel Microfluidic Technology

    PubMed Central

    Ho, Nga T.; Desai, Darash; Zaman, Muhammad H.

    2015-01-01

    Globally, it is estimated that about 10–30% of pharmaceuticals are of poor quality. Poor-quality drugs lead to long-term drug resistance, create morbidity, and strain the financial structure of the health system. The current technologies for substandard drug detection either are too expensive for low-resource regions or only provide qualitative results. To address the current limitations with point-of-care technologies, we have developed an affordable and robust assay to quantify the amount of active pharmaceutical ingredients (APIs) to test product quality. Our novel assay consists of two parts: detection reagent (probe) and a microfluidic testing platform. As antimalarials are of high importance in the global fight against malaria and are often substandard, they are chosen as the model to validate our assay. As a proof-of-concept, we have tested the assay with artesunate pure and substandard samples (Arsuamoon tablets) from Africa and compared with the conventional 96-well plate with spectrophotometer to demonstrate the quantitative efficacy and performance of our system. PMID:25897061

  13. Rapid and specific drug quality testing assay for artemisinin and its derivatives using a luminescent reaction and novel microfluidic technology.

    PubMed

    Ho, Nga T; Desai, Darash; Zaman, Muhammad H

    2015-06-01

    Globally, it is estimated that about 10-30% of pharmaceuticals are of poor quality. Poor-quality drugs lead to long-term drug resistance, create morbidity, and strain the financial structure of the health system. The current technologies for substandard drug detection either are too expensive for low-resource regions or only provide qualitative results. To address the current limitations with point-of-care technologies, we have developed an affordable and robust assay to quantify the amount of active pharmaceutical ingredients (APIs) to test product quality. Our novel assay consists of two parts: detection reagent (probe) and a microfluidic testing platform. As antimalarials are of high importance in the global fight against malaria and are often substandard, they are chosen as the model to validate our assay. As a proof-of-concept, we have tested the assay with artesunate pure and substandard samples (Arsuamoon tablets) from Africa and compared with the conventional 96-well plate with spectrophotometer to demonstrate the quantitative efficacy and performance of our system. PMID:25897061

  14. In vitro susceptibility of Plasmodium vivax to antimalarials in Colombia.

    PubMed

    Fernández, Diana; Segura, César; Arboleda, Margarita; Garavito, Giovanny; Blair, Silvia; Pabón, Adriana

    2014-11-01

    The in vitro susceptibilities of 30 isolates of Plasmodium vivax to a number of antimalarials (chloroquine [CQ], mefloquine, amodiaquine, quinine, and artesunate [AS]) were evaluated. The isolates came from the region of Urabá in Colombia, in which malaria is endemic, and were evaluated by the schizont maturation test. The 50% inhibitory concentration (IC50) was 0.6 nM (95% confidence interval [CI], 0.3 to 1.0 nM) for artesunate, 8.5 nM (95% CI, 5.6 to 13.0 nM) for amodiaquine, 23.3 nM (95% CI, 12.4 to 44.1 nM) for chloroquine, 55.6 nM (95% CI, 36.8 to 84.1 nM) for mefloquine, and 115.3 nM (95% CI, 57.7 to 230.5 nM) for quinine. The isolates were classified according to whether the initial parasites were mature or immature trophozoites (Tfz). It was found that the IC50s for chloroquine and artesunate were significantly different in the two aforementioned groups (P < 0.001). The IC50s of CQ and AS were higher in the isolates from mature Tfz (CQ, 39.3 nM versus 17 nM; AS, 1.4 nM versus 0.3 nM), and 10% of the isolates showed lower susceptibilities to one of the antimalarial drugs, 13.3% to two antimalarial drugs, and 3.3% to more than three antimalarial drugs. It should be highlighted that despite the extensive use of chloroquine in Colombia, P. vivax continues to be susceptible to antimalarials. This is the first report, to our knowledge, showing in vitro susceptibilities of P. vivax isolates to antimalarials in Colombia.

  15. Drug-induced lupus erythematosus

    MedlinePlus

    ... that caused the condition. Treatment may include: Nonsteroidal anti-inflammatory drugs (NSAIDs) to treat arthritis and pleurisy Corticosteroid creams to treat skin rashes Antimalarial drugs (hydroxychloroquine) to ...

  16. Detecting Counterfeit Antimalarial Tablets by Near-Infrared Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Counterfeit antimalarial drugs are found in many developing countries, but it is challenging to differentiate between genuine and fakes due to their increasing sophistication. Near-infrared spectroscopy (NIRS) is a powerful tool in pharmaceutical forensics, and we tested this technique for discrim...

  17. Potent Plasmodium falciparum Gametocytocidal Activity of Diaminonaphthoquinones, Lead Antimalarial Chemotypes Identified in an Antimalarial Compound Screen

    PubMed Central

    Tanaka, Takeshi Q; Guiguemde, W. Armand; Barnett, David S.; Maron, Maxim I.; Min, Jaeki; Connelly, Michele C.; Suryadevara, Praveen Kumar; Guy, R. Kiplin

    2014-01-01

    Forty percent of the world's population is threatened by malaria, which is caused by Plasmodium parasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. If Plasmodium falciparum gametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria. PMID:25512421

  18. Potent Plasmodium falciparum gametocytocidal activity of diaminonaphthoquinones, lead antimalarial chemotypes identified in an antimalarial compound screen.

    PubMed

    Tanaka, Takeshi Q; Guiguemde, W Armand; Barnett, David S; Maron, Maxim I; Min, Jaeki; Connelly, Michele C; Suryadevara, Praveen Kumar; Guy, R Kiplin; Williamson, Kim C

    2015-03-01

    Forty percent of the world's population is threatened by malaria, which is caused by Plasmodium parasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. If Plasmodium falciparum gametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria. PMID:25512421

  19. Cajachalcone: An Antimalarial Compound from Cajanus cajan Leaf Extract.

    PubMed

    Ajaiyeoba, E O; Ogbole, O O; Abiodun, O O; Ashidi, J S; Houghton, P J; Wright, C W

    2013-01-01

    Cajanus cajan L, a member of the family Fabaceae, was identified from the Nigerian antimalarial ethnobotany as possessing antimalarial properties. The bioassay-guided fractionation of the crude methanol extract of C. cajan leaves was done in vitro using the multiresistant strain of Plasmodium falciparum (K1) in the parasite lactate dehydrogenase assay. Isolation of compound was achieved by a combination of chromatographic techniques, while the structure of the compound was elucidated by spectroscopy. This led to the identification of a cajachalcone, 2',6'-dihydroxy-4-methoxy chalcone, as the biologically active constituent from the ethyl acetate fraction. Cajachalcone had an IC50 value of 2.0  μ g/mL (7.4  μ M) and could be a lead for anti-malarial drug discovery. PMID:23970954

  20. Quinine conjugates and quinine analogues as potential antimalarial agents.

    PubMed

    Jones, Rachel A; Panda, Siva S; Hall, C Dennis

    2015-06-01

    Malaria is a tropical disease, prevalent in Southeast Asia and Africa, resulting in over half a million deaths annually; efforts to develop new antimalarial agents are therefore particularly important. Quinine continues to play a role in the fight against malaria, but quinoline derivatives are more widely used. Drugs based on the quinoline scaffold include chloroquine and primaquine, which are able to act against the blood and liver stages of the parasite's life cycle. The purpose of this review is to discuss reported biologically active compounds based on either the quinine or quinoline scaffold that may have enhanced antimalarial activity. The review emphasises hybrid molecules, and covers advances made in the last five years. The review is divided into three sections: modifications to the quinine scaffold, modifications to aminoquinolines and finally metal-containing antimalarial compounds.

  1. Artemisinins: pharmacological actions beyond anti-malarial.

    PubMed

    Ho, Wanxing Eugene; Peh, Hong Yong; Chan, Tze Khee; Wong, W S Fred

    2014-04-01

    Artemisinins are a family of sesquiterpene trioxane lactone anti-malarial agents originally derived from Artemisia annua L. The anti-malarial action of artemisinins involves the formation of free radicals via cleavage of the endoperoxide bond in its structure, which mediate eradication of the Plasmodium species. With its established safety record in millions of malarial patients, artemisinins are also being investigated in diseases like infections, cancers and inflammation. Artemisinins have been reported to possess robust inhibitory effects against viruses (e.g. Human cytomegalovirus), protozoa (e.g. Toxoplasma gondii), helminths (e.g. Schistosoma species and Fasciola hepatica) and fungi (e.g. Cryptococcus neoformans). Artemisinins have demonstrated cytotoxic effects against a variety of cancer cells by inducing cell cycle arrest, promoting apoptosis, preventing angiogenesis, and abrogating cancer invasion and metastasis. Artemisinins have been evaluated in animal models of autoimmune diseases, allergic disorders and septic inflammation. The anti-inflammatory effects of artemisinins have been attributed to the inhibition of Toll-like receptors, Syk tyrosine kinase, phospholipase Cγ, PI3K/Akt, MAPK, STAT-1/3/5, NF-κB, Sp1 and Nrf2/ARE signaling pathways. This review provides a comprehensive update on non-malarial use of artemisinins, modes of action of artemisinins in different disease conditions, and drug development of artemisinins beyond anti-malarial. With the concerted efforts in the novel synthesis of artemisinin analogs and clinical pharmacology of artemisinins, it is likely that artemisinin drugs will become a major armamentarium combating a variety of human diseases beyond malaria. PMID:24316259

  2. Artemisinin and the antimalarial endoperoxides: from herbal remedy to targeted chemotherapy.

    PubMed Central

    Meshnick, S R; Taylor, T E; Kamchonwongpaisan, S

    1996-01-01

    Artemisinin and its derivatives are endoperoxide-containing compounds which represent a promising new class of antimalarial drugs. In the presence of intraparasitic iron, these drugs are converted into free radicals and other electrophilic intermediates which then alkylate specific malaria target proteins. Combinations of available derivatives and other antimalarial agents show promise both as first-line agents and in the treatment of severe disease. PMID:8801435

  3. [Quality management systems in drugs regulatory authorities: social impact].

    PubMed

    Frías-Ferreiro, G; Ysa-Sánchez, A M; García-Gutiérrez, B; García-García, V

    2010-01-01

    The aim of this paper is to illustrate the social impact of drugs regulatory authorities' procedures, viewed from the perspective of the implementation of a quality management system. A review of drug regulations and their influence on quality and health systems is described.

  4. QSAR and pharmacophore modeling of natural and synthetic antimalarial prodiginines.

    PubMed

    Singh, Baljinder; Vishwakarma, Ram A; Bharate, Sandip B

    2013-09-01

    Prodiginines are a family of linear and cyclic oligopyrrole red-pigmented compounds possessing antibacterial, anticancer and immunosuppressive activities and are produced by actinomycetes and other eubacteria. Recently, prodiginines have been reported to possess potent in vitro as well as in vivo antimalarial activity against chloroquine sensitive D6 and multi-drug resistant Dd2 strains of Plasmodium falciparum. In the present paper, a QSAR and pharmacophore modeling for a series of natural and synthetic prodiginines was performed to find out structural features which are crucial for antimalarial activity against these D6 and Dd2 Plasmodium strains. The study indicated that inertia moment 2 length, Kier Chi6 (path) index, kappa 3 index and Wiener topological index plays important role in antimalarial activity against D6 strain whereas descriptors inertia moment 2 length, ADME H-bond donors, VAMP polarization XX component and VAMP quadpole XZ component play important role in antimalarial activity against Dd2 strain. Furthermore, a five-point pharmacophore (ADHRR) model with one H-bond acceptor (A), one H-bond donor (D), one hydrophobic group (H) and two aromatic rings (R) as pharmacophore features was developed for D6 strain by PHASE module of Schrodinger suite. Similarly a six-point pharmacophore AADDRR was developed for Dd2 strain activity. All developed QSAR models showed good correlation coefficient (r² > 0.7), higher F value (F >20) and excellent predictive power (Q² > 0.6). Developed models will be highly useful for predicting antimalarial activity of new compounds and could help in designing better molecules with enhanced antimalarial activity. Furthermore, calculated ADME properties indicated drug-likeness of prodiginines.

  5. Antimalarial activity of HIV-1 protease inhibitor in chromone series.

    PubMed

    Lerdsirisuk, Pradith; Maicheen, Chirattikan; Ungwitayatorn, Jiraporn

    2014-12-01

    Increasing parasite resistance to nearly all available antimalarial drugs becomes a serious problem to human health and necessitates the need to continue the search for new effective drugs. Recent studies have shown that clinically utilized HIV-1 protease (HIV-1 PR) inhibitors can inhibit the in vitro and in vivo growth of Plasmodium falciparum. In this study, a series of chromone derivatives possessing HIV-1 PR inhibitory activity has been tested for antimalarial activity against P. falciparum (K1 multi-drug resistant strain). Chromone 15, the potent HIV-1 PR inhibitor (IC50=0.65μM), was found to be the most potent antimalarial compound with IC50=0.95μM while primaquine and tafenoquine showed IC50=2.41 and 1.95μM, respectively. Molecular docking study of chromone compounds against plasmepsin II, an aspartic protease enzyme important in hemoglobin degradation, revealed that chromone 15 exhibited the higher binding affinity (binding energy=-13.24kcal/mol) than the known PM II inhibitors. Thus, HIV-1 PR inhibitor in chromone series has the potential to be a new class of antimalarial agent. PMID:25462990

  6. Quality of Artemisinin-Based Combination Formulations for Malaria Treatment: Prevalence and Risk Factors for Poor Quality Medicines in Public Facilities and Private Sector Drug Outlets in Enugu, Nigeria

    PubMed Central

    Kaur, Harparkash; Allan, Elizabeth Louise; Mamadu, Ibrahim; Hall, Zoe; Ibe, Ogochukwu; El Sherbiny, Mohamed; van Wyk, Albert; Yeung, Shunmay; Swamidoss, Isabel; Green, Michael D.; Dwivedi, Prabha; Culzoni, Maria Julia; Clarke, Siân; Schellenberg, David; Fernández, Facundo M.; Onwujekwe, Obinna

    2015-01-01

    Background Artemisinin-based combination therapies are recommended by the World Health Organisation (WHO) as first-line treatment for Plasmodium falciparum malaria, yet medication must be of good quality for efficacious treatment. A recent meta-analysis reported 35% (796/2,296) of antimalarial drug samples from 21 Sub-Saharan African countries, purchased from outlets predominantly using convenience sampling, failed chemical content analysis. We used three sampling strategies to purchase artemisinin-containing antimalarials (ACAs) in Enugu metropolis, Nigeria, and compared the resulting quality estimates. Methods ACAs were purchased using three sampling approaches - convenience, mystery clients and overt, within a defined area and sampling frame in Enugu metropolis. The active pharmaceutical ingredients were assessed using high-performance liquid chromatography and confirmed by mass spectrometry at three independent laboratories. Results were expressed as percentage of APIs stated on the packaging and used to categorise each sample as acceptable quality, substandard, degraded, or falsified. Results Content analysis of 3024 samples purchased from 421 outlets using convenience (n=200), mystery (n=1,919) and overt (n=905) approaches, showed overall 90.8% ACAs to be of acceptable quality, 6.8% substandard, 1.3% degraded and 1.2% falsified. Convenience sampling yielded a significantly higher prevalence of poor quality ACAs, but was not evident by the mystery and overt sampling strategies both of which yielded results that were comparable between each other. Artesunate (n=135; 4 falsified) and dihydroartemisinin (n=14) monotherapy tablets, not recommended by WHO, were also identified. Conclusion Randomised sampling identified fewer falsified ACAs than previously reported by convenience approaches. Our findings emphasise the need for specific consideration to be given to sampling frame and sampling approach if representative information on drug quality is to be obtained

  7. Artemisinin Antimalarials: Preserving the “Magic Bullet”

    PubMed Central

    Maude, Richard J; Woodrow, Charles J; White, Lisa J

    2010-01-01

    The artemisinins are the most effective antimalarial drugs known. They possess a remarkably wide therapeutic index. These agents have been used in traditional Chinese herbal medicine for more than 2,000 years but were not subjected to scientific scrutiny until the 1970s. The first formal clinical trials of the artemisinins, and the development of methods for their industrial scale production, followed rapidly. A decade later, Chinese scientists shared their findings with the rest of the world; since then, a significant body of international trial evidence has confirmed these drugs to be far superior to any available alternatives. In particular, they have the ability to rapidly kill a broad range of asexual parasite stages at safe concentrations that are consistently achievable via standard dosing regimens. As their half-life is very short, there was also thought to be a low risk of resistance. These discoveries coincided with the appearance and spread of resistance to all the other major classes of antimalarials. As a result, the artemisinins now form an essential element of recommended first-line antimalarial treatment regimens worldwide. To minimize the risk of artemisinin resistance, they are recommended to be used to treat uncomplicated malaria in combination with other antimalarials as artemisinin combination therapies (ACTs). Their rollout has resulted in documented reductions in malaria prevalence in a number of African and Asian countries. Unfortunately, there are already worrisome early signs of artemisinin resistance appearing in western Cambodia. If this resistance were to spread, it would be disastrous for malaria control efforts worldwide. The enormous challenge for the international community is how to avert this catastrophe and preserve the effectiveness of this antimalarial “magic bullet”. Drug Dev Res 71: 12–19, 2010. © 2009 Wiley-Liss, Inc. PMID:21399699

  8. QSAR models for anti-malarial activity of 4-aminoquinolines.

    PubMed

    Masand, Vijay H; Toropov, Andrey A; Toropova, Alla P; Mahajan, Devidas T

    2014-03-01

    In the present study, predictive quantitative structure - activity relationship (QSAR) models for anti-malarial activity of 4-aminoquinolines have been developed. CORAL, which is freely available on internet (http://www.insilico.eu/coral), has been used as a tool of QSAR analysis to establish statistically robust QSAR model of anti-malarial activity of 4-aminoquinolines. Six random splits into the visible sub-system of the training and invisible subsystem of validation were examined. Statistical qualities for these splits vary, but in all these cases, statistical quality of prediction for anti-malarial activity was quite good. The optimal SMILES-based descriptor was used to derive the single descriptor based QSAR model for a data set of 112 aminoquinolones. All the splits had r(2)> 0.85 and r(2)> 0.78 for subtraining and validation sets, respectively. The three parametric multilinear regression (MLR) QSAR model has Q(2) = 0.83, R(2) = 0.84 and F = 190.39. The anti-malarial activity has strong correlation with presence/absence of nitrogen and oxygen at a topological distance of six. PMID:24801104

  9. New Analytical Monographs on TCM Herbal Drugs for Quality Proof.

    PubMed

    Wagner, Hildebert; Bauer, Rudolf; Melchart, Dieter

    2016-01-01

    Regardless of specific national drug regulations there is an international consensus that all TCM drugs must meet stipulated high quality standards focusing on authentication, identification and chemical composition. In addition, safety of all TCM drugs prescribed by physicians has to be guaranteed. During the 25 years history of the TCM hospital Bad Kötzting, 171 TCM drugs underwent an analytical quality proof including thin layer as well as high pressure liquid chromatography. As from now mass spectroscopy will also be available as analytical tool. The findings are compiled and already published in three volumes of analytical monographs. One more volume will be published shortly, and a fifth volume is in preparation. The main issues of the analytical procedure in TCM drugs like authenticity, botanical nomenclature, variability of plant species and parts as well as processing are pointed out and possible ways to overcome them are sketched.

  10. New Analytical Monographs on TCM Herbal Drugs for Quality Proof.

    PubMed

    Wagner, Hildebert; Bauer, Rudolf; Melchart, Dieter

    2016-01-01

    Regardless of specific national drug regulations there is an international consensus that all TCM drugs must meet stipulated high quality standards focusing on authentication, identification and chemical composition. In addition, safety of all TCM drugs prescribed by physicians has to be guaranteed. During the 25 years history of the TCM hospital Bad Kötzting, 171 TCM drugs underwent an analytical quality proof including thin layer as well as high pressure liquid chromatography. As from now mass spectroscopy will also be available as analytical tool. The findings are compiled and already published in three volumes of analytical monographs. One more volume will be published shortly, and a fifth volume is in preparation. The main issues of the analytical procedure in TCM drugs like authenticity, botanical nomenclature, variability of plant species and parts as well as processing are pointed out and possible ways to overcome them are sketched. PMID:27271998

  11. Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement

    PubMed Central

    Shen, Shuo; Liu, Shu-Zhi; Zhang, Yu-Shi; Du, Mao-Bo; Liang, Ai-Hua; Song, Li-Hua; Ye, Zu-Guang

    2015-01-01

    Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem–ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data obtained in this study showed that the application of ethosomal technology to antimalarial cataplasm could improve the transdermal delivery of drug, enhance the efficacy, and facilitate practical application in clinic. PMID:26170661

  12. Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement.

    PubMed

    Shen, Shuo; Liu, Shu-Zhi; Zhang, Yu-Shi; Du, Mao-Bo; Liang, Ai-Hua; Song, Li-Hua; Ye, Zu-Guang

    2015-01-01

    Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem-ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data obtained in this study showed that the application of ethosomal technology to antimalarial cataplasm could improve the transdermal delivery of drug, enhance the efficacy, and facilitate practical application in clinic.

  13. Compound antimalarial ethosomal cataplasm: preparation, evaluation, and mechanism of penetration enhancement.

    PubMed

    Shen, Shuo; Liu, Shu-Zhi; Zhang, Yu-Shi; Du, Mao-Bo; Liang, Ai-Hua; Song, Li-Hua; Ye, Zu-Guang

    2015-01-01

    Malaria is still a serious public health problem in some parts of the world. The problems of recurrence and drug resistance are increasingly more serious. Thus, it is necessary to develop a novel antimalarial agent. The objectives of this study were to construct a novel compound antimalarial transdermal nanosystem-ethosomal cataplasm, to investigate its characteristics and efficiency, and to systematically explore the penetration-enhancing mechanisms of ethosomal cataplasm. Artesunate-loaded ethosomes and febrifugine-loaded ethosomes were prepared, and their characteristics were evaluated. Drug-loaded ethosomes were incorporated in the matrix of cataplasm to form the compound antimalarial ethosomal cataplasm. With the help of ethosomal technology, the accumulated permeation quantity of artesunate significantly increased at 8 hours after administration, which was 1.57 times as much as that of conventional cataplasm. Soon after administration, the ethosomal cataplasm could make a large quantity of antimalarial drug quickly penetrate through skin, then the remaining drug in the ethosomal cataplasm could be steadily released. These characteristics of ethosomal cataplasm are favorable for antimalarial drugs to kill Plasmodium spp. quickly and prevent the resurgence of Plasmodium spp. As expected, the ethosomal cataplasm showed good antimalarial efficiency in this experiment. The negative conversion rates were 100% and the recurrence rates were 0% at all dosages. The mechanism of penetration enhancement of the ethosomal cataplasm was systematically explored using an optics microscope, polarization microscope, and transmission electron microscopy. The microstructure, ultrastructure, and birefringent structure in skin were observed. Data obtained in this study showed that the application of ethosomal technology to antimalarial cataplasm could improve the transdermal delivery of drug, enhance the efficacy, and facilitate practical application in clinic. PMID:26170661

  14. [Generic drugs: we must cut pharmaceutical spending but undertaking drug quality].

    PubMed

    Carrillo Norte, Juan Antonio; Postigo Mota, Salvador

    2012-02-01

    The World Health Organization and all drug regulatory agencies (DRA) support the commercialization of generic medicines because they control costs and are irreplaceable therapeutic options in countries lacking the innovator product. Generic drugs are widely considered to be cost-efficient substitutes for brand-name medications. They make up about 20% of the total number of prescriptions in Spain, a figure that is still far from the use of generic drugs in USA and other European countries. Despite economical interest in this issue, in this article we review the interest of generic drugs from a pharmacological and clinical perspective that must undertake drug quality to ensure drug efficacy and safety of the patients. A generic drug (generic drugs, short: generics) is defined as "a drug product that is comparable to brand/reference listed drug product in dosage form, strength, route of administration, quality and performance characteristics, and intended use". Both the reference drug and the generic drug have to demonstrate previously they are therapeutically equivalent. With the exception of parenteral drugs, two products have demonstrated to be therapeutically equivalent if after administration in the same molar dose, their effects with respect to both efficacy and safety are essentially the same, as determined from bioequivalence studies in terms of comparison of appropriate pharmacokinetic parameters and bioavailability. Parenteral formulations, however, are not required to demonstrate therapeutic equivalence because it may be considered self-evident. Such assumptions have never been challenged, but there are reasons to do so for parenteral antimicrobials. It is interesting to highlight that although brand-name drugs and generic drugs are both approved by DRA and may be interchangeable with respect to their clinical effects, they can differ substantially in their appearance. Consumers of brand-name medications receive identical-appearing batches of pills with

  15. Analysis of genetic mutations associated with anti-malarial drug resistance in Plasmodium falciparum from the Democratic Republic of East Timor

    PubMed Central

    de Almeida, Afonso; Arez, Ana Paula; Cravo, Pedro VL; do Rosário, Virgílio E

    2009-01-01

    Background In response to chloroquine (CQ) resistance, the policy for the first-line treatment of uncomplicated malaria in the Democratic Republic of East Timor (DRET) was changed in early 2000. The combination of sulphadoxine-pyrimethamine (SP) was then introduced for the treatment of uncomplicated falciparum malaria. Methods Blood samples were collected in two different periods (2003–2004 and 2004–2005) from individuals attending hospitals or clinics in six districts of the DRET and checked for Plasmodium falciparum infection. 112 PCR-positive samples were inspected for genetic polymorphisms in the pfcrt, pfmdr1, pfdhfr and pfdhps genes. Different alleles were interrogated for potential associations that could be indicative of non-random linkage. Results Overall prevalence of mutations associated with resistance to CQ and SP was extremely high. The mutant form of Pfcrt (76T) was found to be fixed even after five years of alleged CQ removal. There was a significant increase in the prevalence of the pfdhps 437G mutation (X2 = 31.1; p = 0.001) from the first to second survey periods. A non-random association was observed between pfdhfr51/pfdhps437 (p = 0.001) and pfdhfr 59/pfdhps 437 (p = 0.013) alleles. Conclusion Persistence of CQ-resistant mutants even after supposed drug withdrawal suggests one or all of the following: local P. falciparum may still be inadvertently exposed to the drug, that mutant parasites are being "imported" into the country, and/or reduced genetic diversity and low parasite transmission help maintain mutant haplotypes. The association between pfdhfr51/pfdhps437 and pfdhfr 59/pfdhps 437 alleles indicates that these are undergoing concomitant positive selection in the DRET. PMID:19358729

  16. Synthesis and Antimalarial Activities of Cyclen 4-Aminoquinoline Analogs▿

    PubMed Central

    Khan, M. O. Faruk; Levi, Mark S.; Tekwani, Babu L.; Khan, Shabana I.; Kimura, Eiichi; Borne, Ronald F.

    2009-01-01

    In an attempt to augment the efficacy of 7-chloro 4-aminoquinoline analogs and also to overcome resistance to antimalarial agents, we synthesized three cyclen (1,4,7,10-tetraazacyclododecane) analogs of chloroquine [a bisquinoline derivative, 7-chloro-4-(1,4,7,10-tetraaza-cyclododec-1-yl)-quinoline HBr, and a 7-chloro-4-(1,4,7,10-tetraaza-cyclododec-1-yl)-quinoline-Zn2+ complex]. The bisquinoline displays the most potent in vitro and in vivo antimalarial activities. It displays 50% inhibitory concentrations (IC50s) of 7.5 nM against the D6 (chloroquine-sensitive) clone of Plasmodium falciparum and 19.2 nM against the W2 (chloroquine-resistant) clone, which are comparable to those of artemisinin (10.6 and 5.0 nM, respectively) and lower than those of chloroquine (10.7 and 87.2 nM, respectively), without any evidence of cytotoxicity to mammalian cells, indicating a high selectivity index (>1,333 against D6 clone and >521 against W2 clone). Potent antimalarial activities of the bisquinoline against chloroquine- and mefloquine-resistant strains of P. falciparum were also confirmed by in vitro [3H]hypoxanthine incorporation assay. The in vivo antimalarial activity of the bisquinoline, as determined in P. berghei-infected mice, is comparable to that of chloroquine (50% effective dose, ≤1.1 mg/kg when given orally); no apparent toxicity has been observed up to the highest dose tested (3 × 30 mg/kg). The bisquinoline inhibits in vitro hemozoin (β-hematin) formation with an IC50 of 1.1 μM, which is about 10-fold more potent than chloroquine (IC50 9.5 μM). Overall, this article describes the discovery of a new class of cyclen 4-aminoquinoline analogs as potent antimalarial drugs. PMID:19171802

  17. Antimalarial activity enhancement in hydroxymethylcarbonyl (HMC) isostere-based dipeptidomimetics targeting malarial aspartic protease plasmepsin

    PubMed Central

    Hidaka, Koushi; Kimura, Tooru; Ruben, Adam J.; Uemura, Tsuyoshi; Kamiya, Mami; Kiso, Aiko; Okamoto, Tetsuya; Tsuchiya, Yumi; Hayashi, Yoshio; Freire, Ernesto; Kiso, Yoshiaki

    2015-01-01

    Plasmepsin (Plm) is a potential target for new antimalarial drugs, but most reported Plm inhibitors have relatively low antimalarial activities. We synthesized a series of dipeptide-type HIV protease inhibitors, which contain an allophenylnorstatine-dimethylthioproline scaffold to exhibit potent inhibitory activities against Plm II. Their activities against Plasmodium falciparum in the infected erythrocyte assay were largely different from those against the target enzyme. To improve the antimalarial activity of peptidomimetic Plm inhibitors, we attached substituents on a structure of the highly potent Plm inhibitor KNI-10006. Among the derivatives, we identified alkylamino compounds such as 44 (KNI-10283) and 47 (KNI-10538) with more than 15-fold enhanced antimalarial activity, to the sub-micromolar level, maintaining their potent Plm II inhibitory activity and low cytotoxicity. These results suggest that auxiliary substituents on a specific basic group contribute to deliver the inhibitors to the target Plm. PMID:18952439

  18. Targeting Plasmodium falciparum Hsp90: Towards Reversing Antimalarial Resistance

    PubMed Central

    Shahinas, Dea; Folefoc, Asongna; Pillai, Dylan R.

    2013-01-01

    Malaria continues to exact a great human toll in tropical settings. Antimalarial resistance is rife and the parasite inexorably develops mechanisms to outwit our best drugs, including the now first-line choice, artesunate. Novel strategies to circumvent resistance are needed. Here we detail drug development focusing on heat shock protein 90 and its central role as a chaperone. A growing body of evidence supports the role for Hsp90 inhibitors as adjunctive drugs able to restore susceptibility to traditionally efficacious compounds like chloroquine. PMID:25436880

  19. The role of antimalarial treatment in the elimination of malaria.

    PubMed

    Gosling, R D; Okell, L; Mosha, J; Chandramohan, D

    2011-11-01

    With declining transmission of malaria in several regions of the world and renewed interest in the elimination of malaria, strategies for malaria control using antimalarial drugs are being revisited. Drug-based strategies to reduce transmission of malaria need to target the asymptomatic carriers of infection. Drugs that are effective against gametocytes are few in number, but it may be possible to reduce gametocyte production by killing the asexual stages, for which more drugs are available. Drugs for use in large-scale programmes must be safe and tolerable. Strategies include improving access to treatment for malaria with an efficacious drug, intermittent-treatment programmes, and mass drug administration, with and without screening for malaria. Recent proposals have targeted high-risk groups for interventions. None of the strategies has been rigorously tested with appropriate control groups for comparison. Because of the lack of field evidence, modelling has been used. Models have shown, first, that for long-lasting effects, drug administration programmes should be linked with vector control, and second, that if elimination is the aim, programmes are likely to be more successful when applied to smaller populations of a few thousand or less. In order to sustain the gains following the scaling up of vector control and use of artemisinin combination therapies (ACTs), strategies that use antimalarials effectively need to be devised and evidence generated for the most cost-efficient way forward.

  20. Potential antimalarials from African natural products: A reviw

    PubMed Central

    Lawal, Bashir; Shittu, Oluwatosin Kudirat; Kabiru, Adamu Yusuf; Jigam, Ali Audu; Umar, Maimuna Bello; Berinyuy, Eustace Bonghan; Alozieuwa, Blessing Uchenna

    2015-01-01

    Malaria remains an overwhelming infectious disease with significant health challenges in African and other endemic countries globally. Resistance to antimalarial drugs has become one of the most momentous challenges to human health, and thus has necessitated the hunt for new and effective drugs. Consequently, few decades have witnessed a surfeit of research geared to validate the effectiveness of commonly used traditionally medicines against malaria fever. The present review work focuses on documenting natural products from African whose activity has been reported in vivo or in vitro against malaria parasite. Literature was collected using electronic search of published articles (Google Scholar, PubMed, Medline, Sciencedirect, and Science domain) that report on antiplasmodial activity of natural products from differernts Africa region. A total of 652 plant taxa from 146 families, 134 isolated antimalarial compounds from 39 plants species, 2 herbal formulations and 4 insect/products were found to be reported in literature from 1996 to 2015. Plants species from family Asteraceae (11.04%), Fababceae (8.128%), Euphorbiaceae (5.52%), Rubiaceas (5.52%), and Apocyanaceae (5.214%), have received more scientific validation than others. African natural products possess remarkable healing properties as revealed in the various citations as promising antimalarial agents. Some of these natural products from Africa demonstrate high, promising or low activities against Plasmodium parasite. This study also shows that natural products from Africa have a huge amount of novel antimalarial compounds that could serve as a leads for the development of new and effective antiplasmodial drugs. However, in a view of bridging the gap in knowledge, clinical validation of these natural products are of paramount importance. PMID:26649238

  1. Potential antimalarials from African natural products: A reviw.

    PubMed

    Lawal, Bashir; Shittu, Oluwatosin Kudirat; Kabiru, Adamu Yusuf; Jigam, Ali Audu; Umar, Maimuna Bello; Berinyuy, Eustace Bonghan; Alozieuwa, Blessing Uchenna

    2015-01-01

    Malaria remains an overwhelming infectious disease with significant health challenges in African and other endemic countries globally. Resistance to antimalarial drugs has become one of the most momentous challenges to human health, and thus has necessitated the hunt for new and effective drugs. Consequently, few decades have witnessed a surfeit of research geared to validate the effectiveness of commonly used traditionally medicines against malaria fever. The present review work focuses on documenting natural products from African whose activity has been reported in vivo or in vitro against malaria parasite. Literature was collected using electronic search of published articles (Google Scholar, PubMed, Medline, Sciencedirect, and Science domain) that report on antiplasmodial activity of natural products from differernts Africa region. A total of 652 plant taxa from 146 families, 134 isolated antimalarial compounds from 39 plants species, 2 herbal formulations and 4 insect/products were found to be reported in literature from 1996 to 2015. Plants species from family Asteraceae (11.04%), Fababceae (8.128%), Euphorbiaceae (5.52%), Rubiaceas (5.52%), and Apocyanaceae (5.214%), have received more scientific validation than others. African natural products possess remarkable healing properties as revealed in the various citations as promising antimalarial agents. Some of these natural products from Africa demonstrate high, promising or low activities against Plasmodium parasite. This study also shows that natural products from Africa have a huge amount of novel antimalarial compounds that could serve as a leads for the development of new and effective antiplasmodial drugs. However, in a view of bridging the gap in knowledge, clinical validation of these natural products are of paramount importance.

  2. Access to orphan drugs despite poor quality of clinical evidence

    PubMed Central

    Dupont, Alain G; Van Wilder, Philippe B

    2011-01-01

    AIM We analysed the Belgian reimbursement decisions of orphan drugs as compared with those of innovative drugs for more common but equally severe diseases, with special emphasis on the quality of clinical evidence. METHODS Using the National Health Insurance Agency administrative database, we evaluated all submitted orphan drug files between 2002 and 2007. A quality analysis of the clinical evidence in the orphan reimbursement files was performed. The evaluation reports of the French ‘Haute Autorité de Santé’, including the five-point scale parameter ‘Service Médical Rendu (SMR), were examined to compare disease severity. Chi-squared tests (at P < 0.05 significance level) were used to compare the outcome of the reimbursement decisions between orphan and non-orphan innovative medicines. RESULTS Twenty-five files of orphan drugs and 117 files of non-orphan drugs were evaluated. Twenty-two of 25 (88%) submissions of orphan drugs were granted reimbursement as opposed to 74 of the 117 (63%) non-orphan innovative medicines (P = 0.02). Only 52% of the 25 orphan drug files included a randomized controlled trial as opposed to 84% in a random control sample of 25 non-orphan innovative submissions (P < 0.01). The duration of drug exposure was in most cases far too short in relation to the natural history of the disease. CONCLUSIONS Orphan drug designation predicts reimbursement despite poor quality of clinical evidence. The evidence gap at market authorization should be reduced by post-marketing programmes, in which the centralized regulatory and the local reimbursement authorities collaborate in an efficient way across the European Union member states. PMID:21395641

  3. Assessing Website Pharmacy Drug Quality: Safer Than You Think?

    PubMed Central

    Bate, Roger; Hess, Kimberly

    2010-01-01

    Background Internet-sourced drugs are often considered suspect. The World Health Organization reports that drugs from websites that conceal their physical address are counterfeit in over 50 percent of cases; the U.S. Food and Drug Administration (FDA) works with the National Association of Boards of Pharmacy (NABP) to regularly update a list of websites likely to sell drugs that are illegal or of questionable quality. Methods and Findings This study examines drug purchasing over the Internet, by comparing the sales of five popular drugs from a selection of websites stratified by NABP or other ratings. The drugs were assessed for price, conditions of purchase, and basic quality. Prices and conditions of purchase varied widely. Some websites advertised single pills while others only permitted the purchase of large quantities. Not all websites delivered the exact drugs ordered, some delivered no drugs at all; many websites shipped from multiple international locations, and from locations that were different from those advertised on the websites. All drug samples were tested against approved U.S. brand formulations using Raman spectrometry. Many (17) websites substituted drugs, often in different formulations from the brands requested. These drugs, some of which were probably generics or perhaps non-bioequivalent copy versions, could not be assessed accurately. Of those drugs that could be assessed, none failed from “approved”, “legally compliant” or “not recommended” websites (0 out of 86), whereas 8.6% (3 out of 35) failed from “highly not recommended” and unidentifiable websites. Conclusions Of those drugs that could be assessed, all except Viagra® passed spectrometry testing. Of those that failed, few could be identified either by a country of manufacture listed on the packaging, or by the physical location of the website pharmacy. If confirmed by future studies on other drug samples, then U.S. consumers should be able to reduce their risk by

  4. Anticancer Effect of AntiMalarial Artemisinin Compounds

    PubMed Central

    Das, AK

    2015-01-01

    The anti-malarial drug artemisinin has shown anticancer activity in vitro and animal experiments, but experience in human cancer is scarce. However, the ability of artemisinins to kill cancer cells through a variety of molecular mechanisms has been explored. A PubMed search of about 127 papers on anti-cancer effects of antimalarials has revealed that this class of drug, including other antimalarials, have several biological characteristics that include anticancer properties. Experimental evidences suggest that artemisinin compounds may be a therapeutic alternative in highly aggressive cancers with rapid dissemination, without developing drug resistance. They also exhibit synergism with other anticancer drugs with no increased toxicity toward normal cells. It has been found that semisynthetic artemisinin derivatives have much higher antitumor activity than their monomeric counterparts via mechanisms like apoptosis, arrest of cell cycle at G0/G1, and oxidative stress. The exact mechanism of activation and molecular basis of these anticancer effects are not fully elucidated. Artemisinins seem to regulate key factors such as nuclear factor-kappa B, survivin, NOXA, hypoxia-inducible factor-1α, and BMI-1, involving multiple pathways that may affect drug response, drug interactions, drug resistance, and associated parameters upon normal cells. Newer synthetic artemisinins have been developed showing substantial antineoplastic activity, but there is still limited information regarding the mode of action of these synthetic compounds. In view of the emerging data, specific interactions with established chemotherapy need to be further investigated in different cancer cells and their phenotypes and validated further using different semisynthetic and synthetic artemisinin derivatives. PMID:25861527

  5. Detecting counterfeit antimalarial tablets by near-infrared spectroscopy.

    PubMed

    Dowell, Floyd E; Maghirang, Elizabeth B; Fernandez, Facundo M; Newton, Paul N; Green, Michael D

    2008-11-01

    Counterfeit antimalarial drugs are found in many developing countries, but it is challenging to differentiate between genuine and fakes due to their increasing sophistication. Near-infrared spectroscopy (NIRS) is a powerful tool in pharmaceutical forensics, and we tested this technique for discriminating between counterfeit and genuine artesunate antimalarial tablets. Using NIRS, we found that artesunate tablets could be identified as genuine or counterfeit with high accuracy. Multivariate classification models indicated that this discriminatory ability was based, at least partly, on the presence or absence of spectral signatures related to artesunate. This technique can be field-portable and requires little training after calibrations are developed, thus showing great promise for rapid and accurate fake detection. PMID:18703302

  6. Antimalarial Oxoprotoberberine Alkaloids from the Leaves of Miliusa cuneata.

    PubMed

    Promchai, Thanika; Jaidee, Atchara; Cheenpracha, Sarot; Trisuwan, Kongkiat; Rattanajak, Roonglawan; Kamchonwongpaisan, Sumalee; Laphookhieo, Surat; Pyne, Stephen G; Ritthiwigrom, Thunwadee

    2016-04-22

    Five new oxoprotoberberine alkaloids, miliusacunines A-E (1-5), along with nine known compounds, 6-14, were isolated from an acetone extract of the leaves and twigs of Miliusa cuneata. Their structures were elucidated by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicities against the KB and Vero cell lines and for antimalarial activities against the Plasmodium falciparum strains TM4 and K1 (a sensitive and a multi-drug-resistant strain, respectively). Compound 1 showed in vitro antimalarial activity against the TM4 strain, with an IC50 value of 19.3 ± 3.4 μM, and compound 2 demonstrated significant activity against the K1 strain, with an IC50 value of 10.8 ± 4.1 μM. Both compounds showed no discernible cytotoxicity to the Vero cell line at the concentration levels evaluated.

  7. X-ray Spectroscopy for Quality Control of Chemotherapy Drugs

    SciTech Connect

    Greaves, E. D.; Barros, H.; Bermudez, J.; Sajo-Bohus, L.; Angeli-Greaves, M.

    2007-10-26

    We develop a method, employing Compton peak standardization and the use of matrix-matched spiked samples with Total Reflection X-ray Fluorescence (TXRF), for the determination of platinum plasma concentrations of patients undergoing chemotherapy with Pt-bearing drugs. Direct blood plasma analysis attains Pt detection limits of 70 ng/ml. Measurement results of prescribed drug doses are compared to achieved blood Pt concentrations indicating a lack of expected correlations. Direct analysis of Pt-containing infused drugs from a variety of suppliers indicates cases of abnormal concentrations which raises quality control issues. We demonstrate the potential usefulness of the method for pharmacokinetic studies or for routine optimization and quality control of Pt chemotherapy treatments.

  8. Antimalarial activity of fractions of aqueous extract of Acacia nilotica root

    PubMed Central

    Alli, Lukman Adewale; Adesokan, Abdulfatai Ayoade; Salawu, Adeola Oluwakanyinsola

    2016-01-01

    Background: The problem of resistance of malarial parasites to available antimalarial drugs makes the development of new drugs imperative, with natural plant products providing an alternative source for discovering new drugs. Aim: To evaluate the antimalarial activity of eluted fractions of Acacia nilotica root extract and determine the phytochemicals responsible for its antimalarial activity. Materials and Methods: The extract was eluted successively in gradients of solvent mixture (hexane, ethyl acetate, and methanol) in multiples of 100 ml, and each fraction was collected separately. Eluates that showed similar thin layer chromatographic profiles and Rf values were combined to produce 4 main fractions (F-1, F-2, F-3, and F-4), which were tested separately for antimalarial activity using the curative test. Changes in body weight, temperature, and packed cell volume (PCV) were also recorded. Results: Fraction F-1 of A. nilotica at 50 and 100 mg/kg b/w produced significant and dose-dependent reduction in parasite count in Plasmodium berghei infected mice compared to the control, and also significantly increased the survival time of the mice compared to the control group. This fraction also ameliorated the malaria-induced anemia by improving PCV in treated mice. Conclusion: Antimalarial activity of extract of A. nilotica root is probably localized in the F-1 fraction of the extract, which was found to be rich in alkaloids and phenolics. Further study will provide information on the chemical properties of the active metabolites in this fraction. PMID:27104040

  9. P. falciparum In Vitro Killing Rates Allow to Discriminate between Different Antimalarial Mode-of-Action

    PubMed Central

    Sanz, Laura M.; Crespo, Benigno; De-Cózar, Cristina; Ding, Xavier C.; Llergo, Jose L.; Burrows, Jeremy N.; García-Bustos, Jose F.; Gamo, Francisco-Javier

    2012-01-01

    Chemotherapy is still the cornerstone for malaria control. Developing drugs against Plasmodium parasites and monitoring their efficacy requires methods to accurately determine the parasite killing rate in response to treatment. Commonly used techniques essentially measure metabolic activity as a proxy for parasite viability. However, these approaches are susceptible to artefacts, as viability and metabolism are two parameters that are coupled during the parasite life cycle but can be differentially affected in response to drug actions. Moreover, traditional techniques do not allow to measure the speed-of-action of compounds on parasite viability, which is an essential efficacy determinant. We present here a comprehensive methodology to measure in vitro the direct effect of antimalarial compounds over the parasite viability, which is based on limiting serial dilution of treated parasites and re-growth monitoring. This methodology allows to precisely determine the killing rate of antimalarial compounds, which can be quantified by the parasite reduction ratio and parasite clearance time, which are key mode-of-action parameters. Importantly, we demonstrate that this technique readily permits to determine compound killing activities that might be otherwise missed by traditional, metabolism-based techniques. The analysis of a large set of antimalarial drugs reveals that this viability-based assay allows to discriminate compounds based on their antimalarial mode-of-action. This approach has been adapted to perform medium throughput screening, facilitating the identification of fast-acting antimalarial compounds, which are crucially needed for the control and possibly the eradication of malaria. PMID:22383983

  10. Prescription drugs: issues of cost, coverage, and quality.

    PubMed

    Copeland, C

    1999-04-01

    This Issue Brief closely examines expenditures on prescription drugs, and discusses their potential to substitute for other types of health care services. In addition, it describes employer coverage of prescription drugs, direct-to-consumer advertising of prescription drugs, and potential legislation affecting the prescription drug market. Prescription drug expenditures grew at double-digit rates during almost every year since 1980, accelerating to 14.1 percent in 1997. In contrast, total national health expenditures, hospital service expenditures, and physician service expenditures growth rates decreased from approximately 13 percent in 1980 to less than 5 percent in 1997. Private insurance payments for prescription drugs increased 17.7 percent in 1997, after growing 22.1 percent in 1995 and 18.3 percent in 1996. This growth in prescription drug payments compares with 4 percent or less overall annual growth in private insurance payments for each of those three years. From 1993 to 1997, the overwhelming majority of the increases in expenditures on prescription drugs were attributable to increased volume, mix, and availability of pharmaceutical products. In 1997, these factors accounted for more than 80 percent of the growth in prescription drug expenditures. A leading explanation for the sharp growth in drug expenditures is that prescription drugs are a substitute for other forms of health care. While it is difficult to determine the extent to which this substitution occurs, various studies have associated cost savings with the use of pharmaceutical products in treating specific diseases. Evidence suggests that more appropriate utilization of prescription drugs has the potential to lower total expenditures and improve the quality of care. Also, some studies indicate the U.S. health care system needs to improve the way patients use and physicians prescribe current medications. Prescription drug plans offered by employers are likely to undergo changes to ensure that

  11. Quality of Sulfadoxine-Pyrimethamine Given as Antimalarial Prophylaxis in Pregnant Women in Selected Health Facilities in Central Region of Ghana.

    PubMed

    Yeboah, Danny F; Afoakwah, Richmond; Nwaefuna, Ekene K; Verner, Orish; Boampong, Johnson N

    2016-01-01

    The use of sulfadoxine-pyrimethamine (SP) as an intermittent preventive treatment (IPT) against malaria during pregnancy has become a policy in most sub-Sahara African countries and crucially depends on the efficacy of SP. This study sets out to evaluate the effectiveness of the SP given to the pregnant women in some selected health facilities in the Central Region of Ghana to prevent maternal malaria in pregnant women. A total of 543 pregnant women recruited from 7 selected health centres in Central Region of Ghana participated in the study. Parasite density of Plasmodium falciparum was determined from peripheral blood of the pregnant women using microscopy. High performance liquid chromatography (HPLC) and dissolution tester were used to determine the quality of the SP. Malaria infection was recorded in 11.2% of pregnant women who had a history of SP consumption. SP failed the dissolution test. Pregnant women who did not receive IPT-SP were 44%. Low haemoglobin level was recorded in 73.5% of the pregnant women. The results indicated that SP was substandard. IPT-SP is ineffective in preventing malaria infection. PMID:27042341

  12. Animal trypanosomosis: making quality control of trypanocidal drugs possible.

    PubMed

    Sutcliffe, O B; Skellern, G G; Araya, F; Cannavan, A; Sasanya, J J; Dungu, B; van Gool, F; Münstermann, S; Mattioli, R C

    2014-12-01

    African animal trypanosomosis is arguably the most important animal disease impairing livestock agricultural development in sub-Saharan Africa. In addition to vector control, the use oftrypanocidal drugs is important in controlling the impact of the disease on animal health and production in most sub-Saharan countries. However, there are no internationally agreed standards (pharmacopoeia-type monographs or documented product specifications) for the quality control of these compounds. This means that it is impossible to establish independent quality control and quality assurance standards for these agents. An international alliance between the Food and Agriculture Organization of the United Nations, the International Federation for Animal Health, the Global Alliance for Livestock Veterinary Medicines, the University of Strathclyde and the International Atomic Energy Agency (with critical support from the World Organisation for Animal Health) was established to develop quality control and quality assurance standards for trypanocidal drugs, with the aim of transferring these methodologies to two control laboratories in sub-Saharan Africa that will serve as reference institutions for their respective regions. The work of the international alliance will allow development of control measures against sub-standard or counterfeit trypanocidal drugs for treatment of trypanosome infection. Monographs on diminazene aceturate (synonym: diminazene diaceturate), isometamidium chloride hydrochloride, homidium chloride and bromide salts and their relevant veterinary formulations for these agents are given in the annex to this paper. However, the authors do not recommend use of homidium bromide and chloride, because of their proven mutagenic properties in some animal test models and their suspected carcinogenic properties. PMID:25812206

  13. Liposomal Drug Products: A Quality by Design Approach

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoming

    Quality by Design (QbD) principles has been applied to the development of two liposomal formulations, containing a hydrophilic small molecule therapeutic (Tenofovir) and a protein therapeutic (superoxide dismutase). The goal of the research is to provide critical information on 1) how to reduce the preparation variability in liposome formulations, and 2) how to increase drug encapsulation inside liposomes to reduce manufacturing cost. Most notably, an improved liposome preparation method was developed which increased the encapsulation efficiency of hydrophilic molecules. In particular, this method allows for very high encapsulation efficiency. For example, encapsulation efficiencies of up to 50% have been achieved, whereas previously only 20% or less have been reported. Another significant outcome from this research is a first principle mathematical model to predict the encapsulation efficiency of hydrophilic drugs in unilamellar liposomes. This mathematical model will be useful in: formulation development to rapidly achieve optimized formulations; comparison of drug encapsulation efficiencies of liposomes prepared using different methods; and assisting in the development of suitable process analytical technologies to achieve real-time monitoring and control of drug encapsulation during manufacturing. A novel two-stage reverse dialysis in vitro release testing method has also been developed for passively targeted liposomes, which uses the first stage to mimic the circulation of liposomes in the body and the second stage to imitate the drug release process at the target. The developed in vitro release testing method can be used to distinguish formulations with varied compositions for quality control testing purposes. This developed method may pave the way to the development of more biorelevant quality control testing methods for liposomal drug products in the future. The QbD case studies performed in this research are examples of how this approach can be used to

  14. Exploratory Study on Drug Users' Perspectives on Quality of Life: More than Health-Related Quality of Life?

    ERIC Educational Resources Information Center

    De Maeyer, Jessica; Vanderplasschen, Wouter; Broekaert, Eric

    2009-01-01

    In drug treatment outcome literature, a focus on objective and socially desirable indicators of change (e.g. no drug use) has predominated, while outcome indicators that are important for drug users themselves (e.g. quality of life, satisfaction with treatment) have largely been neglected. Nonetheless, Quality of Life (QoL) has become an important…

  15. Emergence of pyrido quinoxalines as new family of antimalarial agents.

    PubMed

    Chandra Shekhar, A; Shanthan Rao, P; Narsaiah, B; Allanki, Aparna Devi; Sijwali, Puran Singh

    2014-04-22

    A series of novel N-alkyl dihydro pyrido quinoxaline derivatives were synthesized using Gould-Jacobs reaction and evaluated their antimalarial activity in vitro against chloroquine sensitive (3D7) and drug resistant (Dd2) strains of Plasmodium falciparum. Among the compounds tested, 10 compounds were more potent than their structural standard analog ciprofloxacin, including 2 derivatives 5e and 5h, which showed 3.3-7.4 times more potency than ciprofloxacin against both the parasite strains. The results are encouraging and a lead molecule may emerge which is useful alone or in combination therapy.

  16. Fixed dose combination of arterolane and piperaquine: a newer prospect in antimalarial therapy.

    PubMed

    Patil, Cy; Katare, Ss; Baig, Ms; Doifode, Sm

    2014-07-01

    Malaria has been very prevalent vector-borne disease in India and until date bears enormous implications on health care services of the country. Over the period of time, the development of resistance to traditional antimalarials like chloroquine has been posed as major deterrent in efforts of malaria control. As the drug resistance is today universally prevalent, especially in Plasmodium falciparum species, major burden of malarial control resides with the new artemisinin drug class. However, arterolane is one of the first fully synthetic non-artemisinin antimalarial compound with rapid schizontocidal activity, hence offering an alternative to artemisinin drugs in malaria control. Piperaquine is a synthetic bisquinoline (4-amioquinoline Antimalarial) with slow and longer schizontocidal activity. Therefore their combination has been shown to provide rapid parasitemic clearance and quick relief of most malaria-related symptoms along with prevention of recrudescences. This combination was approved by Drugs Controller General of India in 2011 for treatment of uncomplicated P. falciparum malaria. The article is aimed at to review this newer prospect in antimalarial therapy for which comprehensive database search was done in Google, Google Scholar, PubMed using the terms "Malaria," "Arterolane," "OZ277," "Piperaquine," and "Artemisinin combination therapy." A total of 323 articles were screened and 28 articles were considered for this review along with the World Health Organization and National malarial program guidelines.

  17. Fixed Dose Combination of Arterolane and Piperaquine: A Newer Prospect in Antimalarial Therapy

    PubMed Central

    Patil, CY; Katare, SS; Baig, MS; Doifode, SM

    2014-01-01

    Malaria has been very prevalent vector-borne disease in India and until date bears enormous implications on health care services of the country. Over the period of time, the development of resistance to traditional antimalarials like chloroquine has been posed as major deterrent in efforts of malaria control. As the drug resistance is today universally prevalent, especially in Plasmodium falciparum species, major burden of malarial control resides with the new artemisinin drug class. However, arterolane is one of the first fully synthetic non-artemisinin antimalarial compound with rapid schizontocidal activity, hence offering an alternative to artemisinin drugs in malaria control. Piperaquine is a synthetic bisquinoline (4-amioquinoline Antimalarial) with slow and longer schizontocidal activity. Therefore their combination has been shown to provide rapid parasitemic clearance and quick relief of most malaria-related symptoms along with prevention of recrudescences. This combination was approved by Drugs Controller General of India in 2011 for treatment of uncomplicated P. falciparum malaria. The article is aimed at to review this newer prospect in antimalarial therapy for which comprehensive database search was done in Google, Google Scholar, PubMed using the terms “Malaria,” “Arterolane,” “OZ277,” “Piperaquine,” and “Artemisinin combination therapy.” A total of 323 articles were screened and 28 articles were considered for this review along with the World Health Organization and National malarial program guidelines. PMID:25221689

  18. Computational studies of new potential antimalarial compounds--stereoelectronic complementarity with the receptor.

    PubMed

    Portela, César; Afonso, Carlos M M; Pinto, Madalena M M; Ramos, Maria João

    2003-09-01

    One of the most important pharmacological mechanisms of antimalarial action is the inhibition of the aggregation of hematin into hemozoin. We present a group of new potential antimalarial molecules for which we have performed a DFT study of their stereoelectronic properties. Additionally, the same calculations were carried out for the two putative drug receptors involved in the referred activity, i.e., hematin mu-oxo dimer and hemozoin. A complementarity between the structural and electronic profiles of the planned molecules and the receptors can be observed. A docking study of the new compounds in relation to the two putative receptors is also presented, providing a correlation with the defined electrostatic complementarity.

  19. Repositioning: the fast track to new anti-malarial medicines?

    PubMed Central

    2014-01-01

    Background Repositioning of existing drugs has been suggested as a fast track for developing new anti-malarial agents. The compound libraries of GlaxoSmithKline (GSK), Pfizer and AstraZeneca (AZ) comprising drugs that have undergone clinical studies in other therapeutic areas, but not achieved approval, and a set of US Food and Drug Administration (FDA)-approved drugs and other bio-actives were tested against Plasmodium falciparum blood stages. Methods Molecules were tested initially against erythrocytic co-cultures of P. falciparum to measure proliferation inhibition using one of the following methods: SYBR®I dye DNA staining assay (3D7, K1 or NF54 strains); [3H] hypoxanthine radioisotope incorporation assay (3D7 and 3D7A strain); or 4’,6-diamidino-2-phenylindole (DAPI) DNA imaging assay (3D7 and Dd2 strains). After review of the available clinical pharmacokinetic and safety data, selected compounds with low μM activity and a suitable clinical profile were tested in vivo either in a Plasmodium berghei four-day test or in the P. falciparum Pf3D70087/N9 huSCID ‘humanized’ mouse model. Results Of the compounds included in the GSK and Pfizer sets, 3.8% (9/238) had relevant in vitro anti-malarial activity while 6/100 compounds from the AZ candidate drug library were active. In comparison, around 0.6% (24/3,800) of the FDA-approved drugs and other bio-actives were active. After evaluation of available clinical data, four investigational drugs, active in vitro were tested in the P. falciparum humanized mouse model: UK-112,214 (PAF-H1 inhibitor), CEP-701 (protein kinase inhibitor), CEP-1347 (protein kinase inhibitor), and PSC-833 (p-glycoprotein inhibitor). Only UK-112,214 showed significant efficacy against P. falciparum in vivo, although at high doses (ED90 131.3 mg/kg [95% CI 112.3, 156.7]), and parasitaemia was still present 96 hours after treatment commencement. Of the six actives from the AZ library, two compounds (AZ-1 and AZ-3) were marginally

  20. Insights into the Role of Heme in the Mechanism of Action of Antimalarials

    PubMed Central

    Combrinck, Jill M.; Mabotha, Tebogo E.; Ncokazi, Kanyile K.; Ambele, Melvin A.; Taylor, Dale; Smith, Peter J.; Hoppe, Heinrich C.; Egan, Timothy J.

    2012-01-01

    Using cell fractionation and measurement of Fe(III)heme-pyridine, the antimalarial chloroquine (CQ) has been shown to cause a dose-dependent decrease in hemozoin and concomitant increase in toxic “free” heme in cultured Plasmodium falciparum that is directly correlated with parasite survival. Transmission electron microscopy techniques have further shown that heme is redistributed from the parasite digestive vacuole to the cytoplasm and that CQ disrupts hemozoin crystal growth, resulting in mosaic boundaries in the crystals formed in the parasite. Extension of the cell fractionation study to other drugs has shown that artesunate, amodiaquine, lumefantrine, mefloquine and quinine, all clinically important antimalarials, also inhibit hemozoin formation in the parasite cell, while the antifolate pyrimethamine and its combination with sulfadoxine do not. This study finally provides direct evidence in support of the hemozoin inhibition hypothesis for the mechanism of action of CQ and shows that other quinoline and related antimalarials inhibit cellular hemozoin formation. PMID:23043646

  1. Antimalarial activity of anthothecol derived from Khaya anthotheca (Meliaceae).

    PubMed

    Lee, Sung-Eun; Kim, Mi-Ran; Kim, Jeong-Han; Takeoka, Gary R; Kim, Tae-Wan; Park, Byeoung-Soo

    2008-06-01

    Antimalarial activity of anthothecol, a limonoid of Khaya anthotheca (Meliaceae) against Plasmodium falciparum was tested using a [(3)H]-hypoxanthine and 48h culture assay in vitro. Anthotechol showed potent antimalarial activity against malaria parasites with IC(50) values of 1.4 and 0.17microM using two different assays. Also, gedunin had antimalarial activity with IC(50) values of 3.1 and 0.14microM. However, the citrus limonoids, limonin and obacunone did not show any antimalarial activity. The antimalarial activities were compared with the three currently used antimalarial medicines quinine, chloroquinine and artemisinin. PMID:17913482

  2. Haem polymerase as a novel target of antimalarial action of cyproheptadine.

    PubMed

    Agrawal, Rashmi; Tripathi, Renu; Tekwani, Babu L; Jain, S K; Dutta, Guru P; Shukla, Onkar P

    2002-11-01

    An antihistaminic drug, cyproheptadine (20-25mg/kg x 4 days), showed significant schizontocidal activity in the blood against a lethal multidrug-resistant (MDR) strain of Plasmodium yoelii nigeriensis (highly resistant to chloroquine, mefloquine, and quinine); the protection of mice ranged between 75 and 100%. A combination of cyproheptadine (15 mg/kg) and chloroquine improved antimalarial activity compared to treatment with either drug alone, whereas a combination of cyproheptadine with quinine or mefloquine did not improve its antimalarial activity. Chloroquine and cyproheptadine inhibited haem polymerization activity in cell-free extracts and in in vivo experiments with MDR P. yoelii, but the combination did not cause a more significant inhibition than found with either drug alone. Cyproheptadine has been shown to produce dose-dependent inhibition of haem polymerization activity both in vitro and in vivo. The mechanism of the antimalarial action of cyproheptadine and its enhanced antimalarial activity with chloroquine could be due, in part, to their inhibitory effect on haem polymerization.

  3. Potentiation of antimalarial activity of arteether in combination with Vetiver root extract.

    PubMed

    Dhawan, Sangeeta; Gunjan, Sarika; Pal, Anirban; Tripathi, Renu

    2016-05-01

    In malaria, development of resistance towards artemisinin derivatives has urged the need for new drugs or new drug combinations to tackle the drug resistant malaria. We studied the fresh root extract of Vetiver zizanioides (Linn.) Nash (VET) with a CDRI-CIMAP antimalarial α/β arteether (ART) together for their antimalarial potential. Our results showed additive to synergistic antimalarial activity of VET and ART with sum fractional inhibitory concentrations Σ FICs 1.02 ± 0.24 and 1.12 ± 0.32 for chloroquine sensitive (CQS) and chloroquine resistant (CQR) strain of Plasmodium falciparum (William H. Welch), respectively. Further, these combinations were explored against multidrug resistant rodent malaria parasite i.e. P. yoelii nigeriensis. Analysis of in vivo interaction of ART and VET showed that 10 mg/kg x 5 days of ART with 1000 mg/kg of VET x 5 days cured 100% mice infected with MDR parasite, while the same dose of ART could produce only up to 30% cure and VET fraction was not curative at all. Synergism/additiveness, found between VET and ART is reported for the first time. The curative dose of ART in the combination was reduced to its one fourth, and thus limits the side effects, if any. Although antimalarial potential of ART was enhanced by VET, action mechanism of later needs to be elucidated in detail. PMID:27319050

  4. Complex polymorphisms in the Plasmodium falciparum multidrug resistance protein 2 gene and its contribution to antimalarial response.

    PubMed

    Veiga, Maria Isabel; Osório, Nuno S; Ferreira, Pedro Eduardo; Franzén, Oscar; Dahlstrom, Sabina; Lum, J Koji; Nosten, Francois; Gil, José Pedro

    2014-12-01

    Plasmodium falciparum has the capacity to escape the actions of essentially all antimalarial drugs. ATP-binding cassette (ABC) transporter proteins are known to cause multidrug resistance in a large range of organisms, including the Apicomplexa parasites. P. falciparum genome analysis has revealed two genes coding for the multidrug resistance protein (MRP) type of ABC transporters: Pfmrp1, previously associated with decreased parasite drug susceptibility, and the poorly studied Pfmrp2. The role of Pfmrp2 polymorphisms in modulating sensitivity to antimalarial drugs has not been established. We herein report a comprehensive account of the Pfmrp2 genetic variability in 46 isolates from Thailand. A notably high frequency of 2.8 single nucleotide polymorphisms (SNPs)/kb was identified for this gene, including some novel SNPs. Additionally, we found that Pfmrp2 harbors a significant number of microindels, some previously not reported. We also investigated the potential association of the identified Pfmrp2 polymorphisms with altered in vitro susceptibility to several antimalarials used in artemisinin-based combination therapy and with parasite clearance time. Association analysis suggested Pfmrp2 polymorphisms modulate the parasite's in vitro response to quinoline antimalarials, including chloroquine, piperaquine, and mefloquine, and association with in vivo parasite clearance. In conclusion, our study reveals that the Pfmrp2 gene is the most diverse ABC transporter known in P. falciparum with a potential role in antimalarial drug resistance.

  5. A novel multiple-stage antimalarial agent that inhibits protein synthesis

    NASA Astrophysics Data System (ADS)

    Baragaña, Beatriz; Hallyburton, Irene; Lee, Marcus C. S.; Norcross, Neil R.; Grimaldi, Raffaella; Otto, Thomas D.; Proto, William R.; Blagborough, Andrew M.; Meister, Stephan; Wirjanata, Grennady; Ruecker, Andrea; Upton, Leanna M.; Abraham, Tara S.; Almeida, Mariana J.; Pradhan, Anupam; Porzelle, Achim; Martínez, María Santos; Bolscher, Judith M.; Woodland, Andrew; Norval, Suzanne; Zuccotto, Fabio; Thomas, John; Simeons, Frederick; Stojanovski, Laste; Osuna-Cabello, Maria; Brock, Paddy M.; Churcher, Tom S.; Sala, Katarzyna A.; Zakutansky, Sara E.; Jiménez-Díaz, María Belén; Sanz, Laura Maria; Riley, Jennifer; Basak, Rajshekhar; Campbell, Michael; Avery, Vicky M.; Sauerwein, Robert W.; Dechering, Koen J.; Noviyanti, Rintis; Campo, Brice; Frearson, Julie A.; Angulo-Barturen, Iñigo; Ferrer-Bazaga, Santiago; Gamo, Francisco Javier; Wyatt, Paul G.; Leroy, Didier; Siegl, Peter; Delves, Michael J.; Kyle, Dennis E.; Wittlin, Sergio; Marfurt, Jutta; Price, Ric N.; Sinden, Robert E.; Winzeler, Elizabeth A.; Charman, Susan A.; Bebrevska, Lidiya; Gray, David W.; Campbell, Simon; Fairlamb, Alan H.; Willis, Paul A.; Rayner, Julian C.; Fidock, David A.; Read, Kevin D.; Gilbert, Ian H.

    2015-06-01

    There is an urgent need for new drugs to treat malaria, with broad therapeutic potential and novel modes of action, to widen the scope of treatment and to overcome emerging drug resistance. Here we describe the discovery of DDD107498, a compound with a potent and novel spectrum of antimalarial activity against multiple life-cycle stages of the Plasmodium parasite, with good pharmacokinetic properties and an acceptable safety profile. DDD107498 demonstrates potential to address a variety of clinical needs, including single-dose treatment, transmission blocking and chemoprotection. DDD107498 was developed from a screening programme against blood-stage malaria parasites; its molecular target has been identified as translation elongation factor 2 (eEF2), which is responsible for the GTP-dependent translocation of the ribosome along messenger RNA, and is essential for protein synthesis. This discovery of eEF2 as a viable antimalarial drug target opens up new possibilities for drug discovery.

  6. A novel multiple-stage antimalarial agent that inhibits protein synthesis.

    PubMed

    Baragaña, Beatriz; Hallyburton, Irene; Lee, Marcus C S; Norcross, Neil R; Grimaldi, Raffaella; Otto, Thomas D; Proto, William R; Blagborough, Andrew M; Meister, Stephan; Wirjanata, Grennady; Ruecker, Andrea; Upton, Leanna M; Abraham, Tara S; Almeida, Mariana J; Pradhan, Anupam; Porzelle, Achim; Martínez, María Santos; Bolscher, Judith M; Woodland, Andrew; Norval, Suzanne; Zuccotto, Fabio; Thomas, John; Simeons, Frederick; Stojanovski, Laste; Osuna-Cabello, Maria; Brock, Paddy M; Churcher, Tom S; Sala, Katarzyna A; Zakutansky, Sara E; Jiménez-Díaz, María Belén; Sanz, Laura Maria; Riley, Jennifer; Basak, Rajshekhar; Campbell, Michael; Avery, Vicky M; Sauerwein, Robert W; Dechering, Koen J; Noviyanti, Rintis; Campo, Brice; Frearson, Julie A; Angulo-Barturen, Iñigo; Ferrer-Bazaga, Santiago; Gamo, Francisco Javier; Wyatt, Paul G; Leroy, Didier; Siegl, Peter; Delves, Michael J; Kyle, Dennis E; Wittlin, Sergio; Marfurt, Jutta; Price, Ric N; Sinden, Robert E; Winzeler, Elizabeth A; Charman, Susan A; Bebrevska, Lidiya; Gray, David W; Campbell, Simon; Fairlamb, Alan H; Willis, Paul A; Rayner, Julian C; Fidock, David A; Read, Kevin D; Gilbert, Ian H

    2015-06-18

    There is an urgent need for new drugs to treat malaria, with broad therapeutic potential and novel modes of action, to widen the scope of treatment and to overcome emerging drug resistance. Here we describe the discovery of DDD107498, a compound with a potent and novel spectrum of antimalarial activity against multiple life-cycle stages of the Plasmodium parasite, with good pharmacokinetic properties and an acceptable safety profile. DDD107498 demonstrates potential to address a variety of clinical needs, including single-dose treatment, transmission blocking and chemoprotection. DDD107498 was developed from a screening programme against blood-stage malaria parasites; its molecular target has been identified as translation elongation factor 2 (eEF2), which is responsible for the GTP-dependent translocation of the ribosome along messenger RNA, and is essential for protein synthesis. This discovery of eEF2 as a viable antimalarial drug target opens up new possibilities for drug discovery.

  7. A novel multiple-stage antimalarial agent that inhibits protein synthesis

    PubMed Central

    Baragaña, Beatriz; Hallyburton, Irene; Lee, Marcus C. S.; Norcross, Neil R.; Grimaldi, Raffaella; Otto, Thomas D.; Proto, William R.; Blagborough, Andrew M.; Meister, Stephan; Wirjanata, Grennady; Ruecker, Andrea; Upton, Leanna M.; Abraham, Tara S.; Almeida, Mariana J.; Pradhan, Anupam; Porzelle, Achim; Martínez, María Santos; Bolscher, Judith M.; Woodland, Andrew; Norval, Suzanne; Zuccotto, Fabio; Thomas, John; Simeons, Frederick; Stojanovski, Laste; Osuna-Cabello, Maria; Brock, Paddy M.; Churcher, Tom S.; Sala, Katarzyna A.; Zakutansky, Sara E.; Jiménez-Díaz, María Belén; Sanz, Laura Maria; Riley, Jennifer; Basak, Rajshekhar; Campbell, Michael; Avery, Vicky M.; Sauerwein, Robert W; Dechering, Koen J.; Noviyanti, Rintis; Campo, Brice; Frearson, Julie A.; Angulo-Barturen, Iñigo; Ferrer-Bazaga, Santiago; Gamo, Francisco Javier; Wyatt, Paul G.; Leroy, Didier; Siegl, Peter; Delves, Michael J.; Kyle, Dennis E.; Wittlin, Sergio; Marfurt, Jutta; Price, Ric N.; Sinden, Robert E.; Winzeler, Elizabeth; Charman, Susan A.; Bebrevska, Lidiya; Gray, David W.; Campbell, Simon; Fairlamb, Alan H.; Willis, Paul; Rayner, Julian C.; Fidock, David A.; Read, Kevin D.; Gilbert, Ian H.

    2015-01-01

    Summary There is an urgent need for new drugs to treat malaria, with broad therapeutic potential and novel modes of action, to widen the scope of treatment and to overcome emerging drug resistance. We describe the discovery of DDD107498, a compound with a potent and novel spectrum of antimalarial activity against multiple life-cycle stages of the parasite, with good pharmacokinetic properties, and an acceptable safety profile. DDD107498 demonstrates potential to address a variety of clinical needs, including single dose treatment, transmission blocking and chemoprotection. DDD107498 was developed from a screening programme against blood stage malaria parasites; its molecular target has been identified as translation elongation factor 2 (eEF2), which is responsible for the GTP-dependent translocation of the ribosome along mRNA, and is essential for protein synthesis. This discovery of eEF2 as a viable antimalarial drug target opens up new possibilities for drug discovery. PMID:26085270

  8. Antimalarial activity of Malaysian Plectranthus amboinicus against Plasmodium berghei

    PubMed Central

    Ramli, Norazsida; Ahamed, Pakeer Oothuman Syed; Elhady, Hassan Mohamed; Taher, Muhammad

    2014-01-01

    Context: Malaria is a mosquito-borne disease caused by parasitic protozoa from the genus of Plasmodium. The protozoans have developed resistance against many of current drugs. It is urgent to find an alternative source of new antimalarial agent. In the effort to discover new antimalarial agents, this research has been conducted on Plectranthus amboinicus. Aims: This study was conducted to evaluate the toxicity and antiplasmodial properties of P. amboinicus. Materials and Methods: Acute oral toxicity dose at 5000 mg/kg was conducted to evaluate the safety of this extract. Twenty mice were divided into control and experimental group. All the mice were observed for signs of toxicity, mortality, weight changes and histopathological changes. Antimalarial activity of different extract doses of 50, 200, 400 and 1000 mg/kg were tested in vivo against Plasmodium berghei infections in mice (five mice for each group) during early, established and residual infections. Results: The acute oral toxicity test revealed that no mortality or evidence of adverse effects was seen in the treated mice. The extract significantly reduced the parasitemia by the 50 (P = 0.000), 200 (P = 0.000) and 400 mg/kg doses (P = 0.000) in the in vivo prophylactic assay. The percentage chemo-suppression was calculated as 83.33% for 50 mg/kg dose, 75.62% for 200 mg/kg dose and 90.74% for 400 mg/kg dose. Body weight of all treated groups; T1, T2, T3 and T4 also showed enhancement after 7 days posttreatment. Statistically no reduction of parasitemia calculated for curative and suppressive test. Conclusion: Thus, this extract may give a promising agent to be used as a prophylactic agent of P. berghei infection. PMID:25276063

  9. Stereoselective inhibition of serotonin transporters by antimalarial compounds.

    PubMed

    Beckman, Matthew L; Pramod, Akula Bala; Perley, Danielle; Henry, L Keith

    2014-07-01

    The serotonin (5-HT) transporter (SERT) is an integral membrane protein that functions to reuptake 5-HT released into the synapse following neurotransmission. This role serves an important regulatory mechanism in neuronal homeostasis. Previous studies have demonstrated that several clinically important antimalarial compounds inhibit serotonin (5-hydroxytryptamine, 5-HT) reuptake. In this study, we examined the details of antimalarial inhibition of 5-HT transport in both Drosophila (dSERT) and human SERT (hSERT) using electrophysiologic, biochemical and computational approaches. We found that the cinchona alkaloids quinidine and cinchonine, which have identical stereochemistry about carbons 8 and 9, exhibited the greatest inhibition of dSERT and hSERT transporter function whereas quinine and cinchonidine, enantiomers of quinidine and cinchonine, respectively, were weaker inhibitors of dSERT and hSERT. Furthermore, SERT mutations known to decrease the binding affinity of many antidepressants affected the cinchona alkaloids in a stereo-specific manner where the similar inhibitory profiles for quinine and cinchonidine (8S,9R) were distinct from quinidine and cinchonine (8R,9S). Small molecule docking studies with hSERT homology models predict that quinine and cinchonidine bind to the central 5-HT binding site (S1) whereas quinidine and cinchonine bind to the S2 site. Taken together, the data presented here support binding of cinchona alkaloids to two different sites on SERT defined by their stereochemistry which implies separate modes of transporter inhibition. Notably, the most potent antimalarial inhibitors of SERT appear to preferentially bind to the S2 site. Our findings provide important insight related to how this class of drugs can modulate the serotonergic system as well as identify compounds that may discriminate between the S1 and S2 binding sites and serve as lead compounds for novel SERT inhibitors.

  10. Antimalarial Benzoxaboroles Target Plasmodium falciparum Leucyl-tRNA Synthetase.

    PubMed

    Sonoiki, Ebere; Palencia, Andres; Guo, Denghui; Ahyong, Vida; Dong, Chen; Li, Xianfeng; Hernandez, Vincent S; Zhang, Yong-Kang; Choi, Wai; Gut, Jiri; Legac, Jennifer; Cooper, Roland; Alley, M R K; Freund, Yvonne R; DeRisi, Joseph; Cusack, Stephen; Rosenthal, Philip J

    2016-08-01

    There is a need for new antimalarials, ideally with novel mechanisms of action. Benzoxaboroles have been shown to be active against bacteria, fungi, and trypanosomes. Therefore, we investigated the antimalarial activity and mechanism of action of 3-aminomethyl benzoxaboroles against Plasmodium falciparum Two 3-aminomethyl compounds, AN6426 and AN8432, demonstrated good potency against cultured multidrug-resistant (W2 strain) P. falciparum (50% inhibitory concentration [IC50] of 310 nM and 490 nM, respectively) and efficacy against murine Plasmodium berghei infection when administered orally once daily for 4 days (90% effective dose [ED90], 7.4 and 16.2 mg/kg of body weight, respectively). To characterize mechanisms of action, we selected parasites with decreased drug sensitivity by culturing with stepwise increases in concentration of AN6426. Resistant clones were characterized by whole-genome sequencing. Three generations of resistant parasites had polymorphisms in the predicted editing domain of the gene encoding a P. falciparum leucyl-tRNA synthetase (LeuRS; PF3D7_0622800) and in another gene (PF3D7_1218100), which encodes a protein of unknown function. Solution of the structure of the P. falciparum LeuRS editing domain suggested key roles for mutated residues in LeuRS editing. Short incubations with AN6426 and AN8432, unlike artemisinin, caused dose-dependent inhibition of [(14)C]leucine incorporation by cultured wild-type, but not resistant, parasites. The growth of resistant, but not wild-type, parasites was impaired in the presence of the unnatural amino acid norvaline, consistent with a loss of LeuRS editing activity in resistant parasites. In summary, the benzoxaboroles AN6426 and AN8432 offer effective antimalarial activity and act, at least in part, against a novel target, the editing domain of P. falciparum LeuRS.

  11. Hydroxyethylamine Based Phthalimides as New Class of Plasmepsin Hits: Design, Synthesis and Antimalarial Evaluation.

    PubMed

    Singh, Anil K; Rathore, Sumit; Tang, Yan; Goldfarb, Nathan E; Dunn, Ben M; Rajendran, Vinoth; Ghosh, Prahlad C; Singh, Neelu; Latha, N; Singh, Brajendra K; Rawat, Manmeet; Rathi, Brijesh

    2015-01-01

    A novel class of phthalimides functionalized with privileged scaffolds was designed, synthesized and evaluated as potential inhibitors of plasmepsin 2 (Ki: 0.99 ± 0.1 μM for 6u) and plasmepsin 4 (Ki: 3.3 ± 0.3 μM for 6t), enzymes found in the digestive vacuole of the plasmodium parasite and considered as crucial drug targets. Three compounds were identified as potential candidates for further development. The listed compounds were also assayed for their antimalarial efficacy against chloroquine (CQ) sensitive strain (3D7) of Plasmodium falciparum. Assay of twenty seven hydroxyethylamine derivatives revealed four (5e, 6j, 6o and 6s) as strongly active, which were further evaluated against CQ resistant strain (7GB) of P. falciparum. Compound 5e possessing the piperidinopiperidine moiety exhibited promising antimalarial activity with an IC50 of 1.16 ± 0.04 μM. Further, compounds 5e, 6j, 6o and 6s exhibited low cytotoxic effect on MCF-7 cell line. Compound 6s possessing C2 symmetry was identified as the least cytotoxic with significant antimalarial activity (IC50: 1.30 ± 0.03 μM). The combined presence of hydroxyethylamine and cyclic amines (piperazines and piperidines) was observed as crucial for the activity. The current studies suggest that hydroxyethylamine based molecules act as potent antimalarial agent and may be helpful in drug development.

  12. Hydroxyethylamine Based Phthalimides as New Class of Plasmepsin Hits: Design, Synthesis and Antimalarial Evaluation.

    PubMed

    Singh, Anil K; Rathore, Sumit; Tang, Yan; Goldfarb, Nathan E; Dunn, Ben M; Rajendran, Vinoth; Ghosh, Prahlad C; Singh, Neelu; Latha, N; Singh, Brajendra K; Rawat, Manmeet; Rathi, Brijesh

    2015-01-01

    A novel class of phthalimides functionalized with privileged scaffolds was designed, synthesized and evaluated as potential inhibitors of plasmepsin 2 (Ki: 0.99 ± 0.1 μM for 6u) and plasmepsin 4 (Ki: 3.3 ± 0.3 μM for 6t), enzymes found in the digestive vacuole of the plasmodium parasite and considered as crucial drug targets. Three compounds were identified as potential candidates for further development. The listed compounds were also assayed for their antimalarial efficacy against chloroquine (CQ) sensitive strain (3D7) of Plasmodium falciparum. Assay of twenty seven hydroxyethylamine derivatives revealed four (5e, 6j, 6o and 6s) as strongly active, which were further evaluated against CQ resistant strain (7GB) of P. falciparum. Compound 5e possessing the piperidinopiperidine moiety exhibited promising antimalarial activity with an IC50 of 1.16 ± 0.04 μM. Further, compounds 5e, 6j, 6o and 6s exhibited low cytotoxic effect on MCF-7 cell line. Compound 6s possessing C2 symmetry was identified as the least cytotoxic with significant antimalarial activity (IC50: 1.30 ± 0.03 μM). The combined presence of hydroxyethylamine and cyclic amines (piperazines and piperidines) was observed as crucial for the activity. The current studies suggest that hydroxyethylamine based molecules act as potent antimalarial agent and may be helpful in drug development. PMID:26502278

  13. Antimalarial activity in Xylocarpus granatum (Koen).

    PubMed

    Lakshmi, Vijai; Srivastava, Shishir; Mishra, Sunil Kumar; Srivastava, Mahendra Nath; Srivastava, Kumkum; Puri, Sunil Kumar

    2012-01-01

    The antimalarial activity of Xylocarpus granatum fruits and their active constituents gedunin and xyloccensin-I were investigated using an in vitro model in this study. The chloroform fraction of X. granatum fruits was found to show promising antimalarial activity using an in vitro model of Plasmodium falciparum. On purification of the active fraction, four pure compounds were isolated and characterised, namely gedunin, photogedunin, xyloccensin-I and palmitic acid. Out of these only gedunin and xyloccensin-I were found to show activity equivalent to the parent active fraction in vitro model. PMID:21787243

  14. In vitro and in vivo characterization of the antimalarial lead compound SSJ-183 in Plasmodium models

    PubMed Central

    Schleiferböck, Sarah; Scheurer, Christian; Ihara, Masataka; Itoh, Isamu; Bathurst, Ian; Burrows, Jeremy N; Fantauzzi, Pascal; Lotharius, Julie; Charman, Susan A; Morizzi, Julia; Shackleford, David M; White, Karen L; Brun, Reto; Wittlin, Sergio

    2013-01-01

    The objective of this work was to characterize the in vitro (Plasmodium falciparum) and in vivo (Plasmodium berghei) activity profile of the recently discovered lead compound SSJ-183. The molecule showed in vitro a fast and strong inhibitory effect on growth of all P. falciparum blood stages, with a tendency to a more pronounced stage-specific action on ring forms at low concentrations. Furthermore, the compound appeared to be equally efficacious on drug-resistant and drug-sensitive parasite strains. In vivo, SSJ-183 showed a rapid onset of action, comparable to that seen for the antimalarial drug artesunate. SSJ-183 exhibited a half-life of about 10 hours and no significant differences in absorption or exposure between noninfected and infected mice. SSJ-183 appears to be a promising new lead compound with an attractive antimalarial profile. PMID:24255594

  15. Bayesian models trained with HTS data for predicting β-haematin inhibition and in vitro antimalarial activity

    PubMed Central

    Wicht, Kathryn J.; Combrinck, Jill M.; Smith, Peter J.; Egan, Timothy J.

    2015-01-01

    A large quantity of high throughput screening (HTS) data for antimalarial activity has become available in recent years. This includes both phenotypic and target-based activity. Realising the maximum value of these data remains a challenge. In this respect, methods that allow such data to be used for virtual screening maximise efficiency and reduce costs. In this study both in vitro antimalarial activity and inhibitory data for β-haematin formation, largely obtained from publically available sources, has been used to develop Bayesian models for inhibitors of β-haematin formation and in vitro antimalarial activity. These models were used to screen two in silico compound libraries. In the first, the 1510 U.S. Food and Drug Administration approved drugs available on PubChem were ranked from highest to lowest Bayesian score based on a training set of β-haematin inhibiting compounds active against P. falciparum that did not include any of the clinical antimalarials or close analogues. The six known clinical antimalarials that inhibit β-haematin formation were ranked in the top 2.1% of compounds. Furthermore, the in vitro antimalarial hit-rate for this prioritised set of compounds was found to be 81% in the case of the subset where activity data are available in PubChem. In the second, a library of about 5,000 commercially available compounds (AldrichCPR) was virtually screened for ability to inhibit β-haematin formation and then for in vitro antimalarial activity. A selection of 34 compounds was purchased and tested, of which 24 were predicted to be β-haematin inhibitors. The hit rate for inhibition of β-haematin formation was found to be 25% and a third of these were active against P. falciparum, corresponding to enrichments estimated at about 25- and 140-fold relative to random screening, respectively. PMID:25573118

  16. Maximizing antimalarial efficacy and the importance of dosing strategies.

    PubMed

    Beeson, James G; Boeuf, Philippe; Fowkes, Freya J I

    2015-01-01

    Artemisinin-based combination therapies (ACTs) are the cornerstone for the treatment of malaria. However, confirmed resistance to artemisinins in South-East Asia, and reports of reduced efficacy of ACTs raise major concerns for malaria treatment and control. Without new drugs to replace artemisinins, it is essential to define dosing strategies that maximize therapeutic efficacy, limit the spread of resistance, and preserve the clinical value of ACTs. It is important to determine the extent to which reduced efficacy of ACTs reflects true resistance versus sub-optimal dosing, and quantify other factors that determine treatment failure. Pooled analyses of individual patient data from multiple clinical trials, by investigators in the Worldwide Antimalarial Resistance Network, have shown high overall efficacy for three widely used ACTs, artemether-lumefantrine, artesunate-amodiaquine, and dihydroartemisinin-piperaquine. Analyses also highlight that suboptimal dosing leads to increased risk of treatment failure, especially among children. In the most recent study, an analysis of clinical trials of artesunate-amodiaquine, widely used among children in Africa, revealed a superior efficacy for fixed-dose combination tablets compared to loose non-fixed dose combinations. This highlights the benefits of fixed-dose combinations as a practical strategy for ensuring optimal antimalarial dosing and maximizing efficacy. Please see related article: http://www.biomedcentral.com/1741-7015/13/66. PMID:25956929

  17. Maximizing antimalarial efficacy and the importance of dosing strategies.

    PubMed

    Beeson, James G; Boeuf, Philippe; Fowkes, Freya J I

    2015-05-09

    Artemisinin-based combination therapies (ACTs) are the cornerstone for the treatment of malaria. However, confirmed resistance to artemisinins in South-East Asia, and reports of reduced efficacy of ACTs raise major concerns for malaria treatment and control. Without new drugs to replace artemisinins, it is essential to define dosing strategies that maximize therapeutic efficacy, limit the spread of resistance, and preserve the clinical value of ACTs. It is important to determine the extent to which reduced efficacy of ACTs reflects true resistance versus sub-optimal dosing, and quantify other factors that determine treatment failure. Pooled analyses of individual patient data from multiple clinical trials, by investigators in the Worldwide Antimalarial Resistance Network, have shown high overall efficacy for three widely used ACTs, artemether-lumefantrine, artesunate-amodiaquine, and dihydroartemisinin-piperaquine. Analyses also highlight that suboptimal dosing leads to increased risk of treatment failure, especially among children. In the most recent study, an analysis of clinical trials of artesunate-amodiaquine, widely used among children in Africa, revealed a superior efficacy for fixed-dose combination tablets compared to loose non-fixed dose combinations. This highlights the benefits of fixed-dose combinations as a practical strategy for ensuring optimal antimalarial dosing and maximizing efficacy. Please see related article: http://www.biomedcentral.com/1741-7015/13/66.

  18. Exploring the 3-piperidin-4-yl-1H-indole scaffold as a novel antimalarial chemotype.

    PubMed

    Santos, Sofia A; Lukens, Amanda K; Coelho, Lis; Nogueira, Fátima; Wirth, Dyann F; Mazitschek, Ralph; Moreira, Rui; Paulo, Alexandra

    2015-09-18

    A series of 3-piperidin-4-yl-1H-indoles with building block diversity was synthesized based on a hit derived from an HTS whole-cell screen against Plasmodium falciparum. Thirty-eight compounds were obtained following a three-step synthetic approach and evaluated for anti-parasitic activity. The SAR shows that 3-piperidin-4-yl-1H-indole is intolerant to most N-piperidinyl modifications. Nevertheless, we were able to identify a new compound (10d) with lead-like properties (MW = 305; cLogP = 2.42), showing antimalarial activity against drug-resistant and sensitive strains (EC50 values ∼ 3 μM), selectivity for malaria parasite and no cross-resistance with chloroquine, thus representing a potential new chemotype for further optimization towards novel and affordable antimalarial drugs.

  19. Antimalarial benzylisoquinoline alkaloid from the rainforest tree Doryphora sassafras.

    PubMed

    Buchanan, Malcolm S; Davis, Rohan A; Duffy, Sandra; Avery, Vicky M; Quinn, Ronald J

    2009-08-01

    Mass-directed isolation of the CH(2)Cl(2)/MeOH extract of Doryphora sassafras resulted in the purification of a new benzylisoquinoline alkaloid, 1-(4-hydroxybenzyl)-6,7-methylenedioxy-2-methylisoquinolinium trifluoroacetate (1), and the known aporphine alkaloid (S)-isocorydine (2). The structures of 1 and 2 were determined by 1D and 2D NMR and MS data analyses. The compounds were isolated during a drug discovery program aimed at identifying new antimalarial leads from a prefractionated natural product library. When tested against two different strains of the parasite Plasmodium falciparum (3D7 and Dd2), 1 displayed IC(50) values of 3.0 and 4.4 microM, respectively. Compound 1 was tested for cytotoxicity toward a human embryonic kidney cell line (HEK293) and displayed no activity at 120 microM.

  20. Optimization of endochin-like quinolones for antimalarial activity

    PubMed Central

    Winter, Rolf; Kelly, Jane X.; Smilkstein, Martin J.; Hinrichs, David; Koop, Dennis R.; Riscoe, Michael K.

    2010-01-01

    Structural analogs of the antimalarial Endochin were synthesized and screened for antiplasmodial activity against drug sensitive and multidrug resistant strains of Plasmodium falciparum. Structural features have been identified that are associated with improved potency while other features are associated with equipotency against an atovaquone-resistant clinical isolate. Relative to endochin the most active compound ELQ-121 shows ≈ 100-fold improvement in IC50 for inhibition of P. falciparum in vitro and it also exhibits enhanced metabolic stability. A polyethylene glycol carbonate ester prodrug of ELQ-121 demonstrated in vivo efficacy against P. yoelii in mice. This is the first report of an endochin-like quinolone that is efficacious in treating malaria in a mammalian host. PMID:21040724

  1. Antimalarial activity of tropical Meliaceae extracts and gedunin derivatives.

    PubMed

    MacKinnon, S; Durst, T; Arnason, J T; Angerhofer, C; Pezzuto, J; Sanchez-Vindas, P E; Poveda, L J; Gbeassor, M

    1997-04-01

    Extracts of 22 species of Meliaceae were examined for antimalarial activity using in vitro tests with two clones of Plasmodium falciparum, one sensitive to chloroquine (W2) and one chloroquine-resistant (D6). Twelve extracts were found to have activity, including extracts of Cedrela odorata wood and Azadirachta indica leaves, which contained the limonoid gedunin. These extracts were more effective against the W2 clone than the D6 clone, suggesting there is no cross-resistance to chloroquine. Gedunin was extracted in quantity, and nine derivatives prepared for a structure-activity study, which revealed essential functionalities for activity. The study also included four other limonoids derived from related Meliaceae. Only gedunin had better activity than chloroquine against the W2 clone. This active principle could be used to standardize a popular crude drug based on traditional use of A. indica in West Africa. PMID:9134742

  2. Antimalarial Chemotherapy: Natural Product Inspired Development of Preclinical and Clinical Candidates with Diverse Mechanisms of Action.

    PubMed

    Fernández-Álvaro, Elena; Hong, W David; Nixon, Gemma L; O'Neill, Paul M; Calderón, Félix

    2016-06-23

    Natural products have played a pivotal role in malaria chemotherapy progressing from quinine and artemisinin to ozonide-based compounds. Many of these natural products have served as template for the design and development of antimalarial drugs currently in the clinic or in the development phase. In this review, we will detail those privileged scaffolds that have guided medicinal chemistry efforts yielding molecules that have reached the clinic. PMID:26791529

  3. Antimalarial Efficacy of Hydroxyethylapoquinine (SN-119) and Its Derivatives

    PubMed Central

    Sanders, Natalie G.; Meyers, David J.

    2014-01-01

    Quinine and other cinchona-derived alkaloids, although recently supplanted by the artemisinins (ARTs), continue to be important for treatment of severe malaria. Quinine and quinidine have narrow therapeutic indices, and a safer quinine analog is desirable, particularly with the continued threat of antimalarial drug resistance. Hydroxyethylapoquinine (HEAQ), used at 8 g a day for dosing in humans in the 1930s and halving mortality from bacterial pneumonias, was shown to cure bird malaria in the 1940s and was also reported as treatment for human malaria cases. Here we describe synthesis of HEAQ and its novel stereoisomer hydroxyethylapoquinidine (HEAQD) along with two intermediates, hydroxyethylquinine (HEQ) and hydroxyethylquinidine (HEQD), and demonstrate comparable but elevated antimalarial 50% inhibitory concentrations (IC50) of 100 to 200 nM against Plasmodium falciparum quinine-sensitive strain 3D7 (IC50, 56 nM). Only HEAQD demonstrated activity against quinine-tolerant P. falciparum strains Dd2 and INDO with IC50s of 300 to 700 nM. HEQD had activity only against Dd2 with an IC50 of 313 nM. In the lethal mouse malaria model Plasmodium berghei ANKA, only HEQD had activity at 20 mg/kg of body weight comparable to that of the parent quinine or quinidine drugs measured by parasite inhibition and 30-day survival. In addition, HEQ, HEQD, and HEAQ (IC50 ≥ 90 μM) have little to no human ether-à-go-go-related gene (hERG) channel inhibition expressed in CHO cells compared to HEAQD, quinine, and quinidine (hERG IC50s of 27, 42, and 4 μM, respectively). HEQD more closely resembled quinine in vitro and in vivo for Plasmodium inhibition and demonstrated little hERG channel inhibition, suggesting that further optimization and preclinical studies are warranted for this molecule. PMID:24247136

  4. In vitro antimalarial activity of extracts of some plants from a biological reserve in Costa Rica.

    PubMed

    Chinchilla, Misael; Valerio, Idalia; Sánchez, Ronald; Mora, Víctor; Bagnarello, Vanessa; Martínez, Laura; Gonzalez, Antonieta; Vanegas, Juan Carlos; Apestegui, Alvaro

    2012-06-01

    Treatment with the usual antimalarial drugs, have induced parasite resistance, reinforcing the need to finding natural antimalarial components that would be found on plants from the forest. Therefore, we decided to look for these components in Costa Rican plants from a protected forest area. Fresh and dry extracts of roots, bark, leaves, flowers and fruits of 25 plants from a biological reserve in Costa Rica, Reserva Biol6gica Alberto Manuel Brenes (REBAMB), were studied in vitro for the presence of substances with antimalarial activity. By studying the inhibition of P berghei schizogony, we assessed the antimalarial activity of several plant extracts: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanacea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) and Myriocarpa longipes (Urticaceae). We used different parts of the plants as well as fresh and dried extracts for testing IC50. The solid content of the extracts ranged from 1-71.9 microg/mL. The fresh extracts showed stronger activity than the dry ones. Since the plants showing the strongest antimalarial activity are very common in Central America, and some similar genera of these plants have shown positives results in South America, we considered important to present these findings for discussion. On the other hand, this is the first systematic study of this kind ever realized in a circumscribed and protected area of

  5. In vitro antimalarial activity of extracts of some plants from a biological reserve in Costa Rica.

    PubMed

    Chinchilla, Misael; Valerio, Idalia; Sánchez, Ronald; Mora, Víctor; Bagnarello, Vanessa; Martínez, Laura; Gonzalez, Antonieta; Vanegas, Juan Carlos; Apestegui, Alvaro

    2012-06-01

    Treatment with the usual antimalarial drugs, have induced parasite resistance, reinforcing the need to finding natural antimalarial components that would be found on plants from the forest. Therefore, we decided to look for these components in Costa Rican plants from a protected forest area. Fresh and dry extracts of roots, bark, leaves, flowers and fruits of 25 plants from a biological reserve in Costa Rica, Reserva Biol6gica Alberto Manuel Brenes (REBAMB), were studied in vitro for the presence of substances with antimalarial activity. By studying the inhibition of P berghei schizogony, we assessed the antimalarial activity of several plant extracts: Aphelandra aurantiaca, A. tridentata (Acanthaceae); Xanthosoma undipes (Araceae); Iriartea deltoidea (Arecaceae); Neurolaena lobata (Asteraceae); Senna papillosa, Pterocarpus hayessi, Lonchocarpus pentaphyllus (Fabaceae); Nectandra membranacea, Persea povedae, Cinamomum chavarrianum (Lauraceae); Hampea appendiculata (Malvaceae); Ruagea glabra, Guarea glabra (Meliaceae); Psidium guajava (Myrtaceae); Bocconia frutescens (Papaveraceae); Piper friedrichsthalii (Piperaceae); Clematis dioica (Ranunculaceae); Prunus annularis (Rosaceae); Siparuna thecaphora (Siparunaceae); Solanum arboreum, Witheringia solanacea (Solanaceae); Ticodendrum incognitum (Ticodendraceae); Heliocarpus appendiculatus (Tiliaceae) and Myriocarpa longipes (Urticaceae). We used different parts of the plants as well as fresh and dried extracts for testing IC50. The solid content of the extracts ranged from 1-71.9 microg/mL. The fresh extracts showed stronger activity than the dry ones. Since the plants showing the strongest antimalarial activity are very common in Central America, and some similar genera of these plants have shown positives results in South America, we considered important to present these findings for discussion. On the other hand, this is the first systematic study of this kind ever realized in a circumscribed and protected area of

  6. Structural requirements of 3-carboxyl-4(1H)-quinolones as potential antimalarials from 2D and 3D QSAR analysis.

    PubMed

    Li, Jiazhong; Li, Shuyan; Bai, Chongliang; Liu, Huanxiang; Gramatica, Paola

    2013-07-01

    Malaria is a fatal tropical and subtropical disease caused by the protozoal species Plasmodium. Many commonly available antimalarial drugs and therapies are becoming ineffective because of the emergence of multidrug resistant Plasmodium falciparum, which drives the need for the development of new antimalarial drugs. Recently, a series of 3-carboxyl-4(1H)-quinolone analogs, derived from the famous compound endochin, were reported as promising candidates for orally efficacious antimalarials. In this study, to analyze the structure-activity relationships (SAR) of these quinolones and investigate the structural requirements for antimalarial activity, the 2D multiple linear regressions (MLR) method and 3D comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods are employed to evolve different QSAR models. All these models give satisfactory results with highly accurate fitting and strong external predictive abilities for chemicals not used in model development. Furthermore, the contour maps from 3D models can provide an intuitive understanding of the key structure features responsible for the antimalarial activities. In conclusion, we summarize the detailed position-specific structural requirements of these derivatives accordingly. All these results are helpful for the rational design of new compounds with higher antimalarial bioactivities.

  7. Identification and deconvolution of cross-resistance signals from antimalarial compounds using multidrug-resistant Plasmodium falciparum strains.

    PubMed

    Chugh, Monika; Scheurer, Christian; Sax, Sibylle; Bilsland, Elizabeth; van Schalkwyk, Donelly A; Wicht, Kathryn J; Hofmann, Natalie; Sharma, Anil; Bashyam, Sridevi; Singh, Shivendra; Oliver, Stephen G; Egan, Timothy J; Malhotra, Pawan; Sutherland, Colin J; Beck, Hans-Peter; Wittlin, Sergio; Spangenberg, Thomas; Ding, Xavier C

    2015-02-01

    Plasmodium falciparum, the most deadly agent of malaria, displays a wide variety of resistance mechanisms in the field. The ability of antimalarial compounds in development to overcome these must therefore be carefully evaluated to ensure uncompromised activity against real-life parasites. We report here on the selection and phenotypic as well as genotypic characterization of a panel of sensitive and multidrug-resistant P. falciparum strains that can be used to optimally identify and deconvolute the cross-resistance signals from an extended panel of investigational antimalarials. As a case study, the effectiveness of the selected panel of strains was demonstrated using the 1,2,4-oxadiazole series, a newly identified antimalarial series of compounds with in vitro activity against P. falciparum at nanomolar concentrations. This series of compounds was to be found inactive against several multidrug-resistant strains, and the deconvolution of this signal implicated pfcrt, the genetic determinant of chloroquine resistance. Targeted mode-of-action studies further suggested that this new chemical series might act as falcipain 2 inhibitors, substantiating the suggestion that these compounds have a site of action similar to that of chloroquine but a distinct mode of action. New antimalarials must overcome existing resistance and, ideally, prevent its de novo appearance. The panel of strains reported here, which includes recently collected as well as standard laboratory-adapted field isolates, is able to efficiently detect and precisely characterize cross-resistance and, as such, can contribute to the faster development of new, effective antimalarial drugs.

  8. Identification and deconvolution of cross-resistance signals from antimalarial compounds using multidrug-resistant Plasmodium falciparum strains.

    PubMed

    Chugh, Monika; Scheurer, Christian; Sax, Sibylle; Bilsland, Elizabeth; van Schalkwyk, Donelly A; Wicht, Kathryn J; Hofmann, Natalie; Sharma, Anil; Bashyam, Sridevi; Singh, Shivendra; Oliver, Stephen G; Egan, Timothy J; Malhotra, Pawan; Sutherland, Colin J; Beck, Hans-Peter; Wittlin, Sergio; Spangenberg, Thomas; Ding, Xavier C

    2015-02-01

    Plasmodium falciparum, the most deadly agent of malaria, displays a wide variety of resistance mechanisms in the field. The ability of antimalarial compounds in development to overcome these must therefore be carefully evaluated to ensure uncompromised activity against real-life parasites. We report here on the selection and phenotypic as well as genotypic characterization of a panel of sensitive and multidrug-resistant P. falciparum strains that can be used to optimally identify and deconvolute the cross-resistance signals from an extended panel of investigational antimalarials. As a case study, the effectiveness of the selected panel of strains was demonstrated using the 1,2,4-oxadiazole series, a newly identified antimalarial series of compounds with in vitro activity against P. falciparum at nanomolar concentrations. This series of compounds was to be found inactive against several multidrug-resistant strains, and the deconvolution of this signal implicated pfcrt, the genetic determinant of chloroquine resistance. Targeted mode-of-action studies further suggested that this new chemical series might act as falcipain 2 inhibitors, substantiating the suggestion that these compounds have a site of action similar to that of chloroquine but a distinct mode of action. New antimalarials must overcome existing resistance and, ideally, prevent its de novo appearance. The panel of strains reported here, which includes recently collected as well as standard laboratory-adapted field isolates, is able to efficiently detect and precisely characterize cross-resistance and, as such, can contribute to the faster development of new, effective antimalarial drugs. PMID:25487796

  9. Identification and Deconvolution of Cross-Resistance Signals from Antimalarial Compounds Using Multidrug-Resistant Plasmodium falciparum Strains

    PubMed Central

    Chugh, Monika; Scheurer, Christian; Sax, Sibylle; Bilsland, Elizabeth; van Schalkwyk, Donelly A.; Wicht, Kathryn J.; Hofmann, Natalie; Sharma, Anil; Bashyam, Sridevi; Singh, Shivendra; Oliver, Stephen G.; Egan, Timothy J.; Malhotra, Pawan; Sutherland, Colin J.; Beck, Hans-Peter; Wittlin, Sergio; Spangenberg, Thomas

    2014-01-01

    Plasmodium falciparum, the most deadly agent of malaria, displays a wide variety of resistance mechanisms in the field. The ability of antimalarial compounds in development to overcome these must therefore be carefully evaluated to ensure uncompromised activity against real-life parasites. We report here on the selection and phenotypic as well as genotypic characterization of a panel of sensitive and multidrug-resistant P. falciparum strains that can be used to optimally identify and deconvolute the cross-resistance signals from an extended panel of investigational antimalarials. As a case study, the effectiveness of the selected panel of strains was demonstrated using the 1,2,4-oxadiazole series, a newly identified antimalarial series of compounds with in vitro activity against P. falciparum at nanomolar concentrations. This series of compounds was to be found inactive against several multidrug-resistant strains, and the deconvolution of this signal implicated pfcrt, the genetic determinant of chloroquine resistance. Targeted mode-of-action studies further suggested that this new chemical series might act as falcipain 2 inhibitors, substantiating the suggestion that these compounds have a site of action similar to that of chloroquine but a distinct mode of action. New antimalarials must overcome existing resistance and, ideally, prevent its de novo appearance. The panel of strains reported here, which includes recently collected as well as standard laboratory-adapted field isolates, is able to efficiently detect and precisely characterize cross-resistance and, as such, can contribute to the faster development of new, effective antimalarial drugs. PMID:25487796

  10. How the media do drugs: quality control and the reporting of drug issues in the UK print media.

    PubMed

    Coomber; Morris; Dunn

    2000-05-01

    Exaggeration, distortion, inaccuracy, sensationalism; each of these labels has been consistently applied to the reporting of drug related issues in the print and other media over the last 40 years and beyond. This research sought to understand what quality control mechanisms are employed by the UK print media in relation to issues related to illicit drugs to ensure accurate, informed and appropriate reporting. It was found that the print media in the UK employ almost no quality control mechanisms to ensure that such reporting takes place and that they predominately rely on the demonstrably insufficient qualities of the 'good reporting' skills that journalists bring to their research and writing. What concerns did exist regarding accuracy related predominately to protecting the publication from being sued for libel and no specific journalistic expertise of drug issues was considered necessary. A discussion of these issues is undertaken followed by the recommendation for the production of a negotiated media guide. PMID:10927199

  11. Synthesis and antimalarial activity of prodigiosenes.

    PubMed

    Marchal, Estelle; Smithen, Deborah A; Uddin, Md Imam; Robertson, Andrew W; Jakeman, David L; Mollard, Vanessa; Goodman, Christopher D; MacDougall, Kristopher S; McFarland, Sherri A; McFadden, Geoffrey I; Thompson, Alison

    2014-06-28

    Several analogues of the natural compound prodigiosin with modified A- and C-rings were synthesised as were some of their tin, cobalt, boron and zinc complexes. The antimalarial activity of these prodigiosenes was evaluated in vitro using the 3D7 Plasmodium falciparum strain. The presence of a nitrogen atom in the A-ring is needed for antimalarial activity but the presence of an alkyl group at the β'-position of the C-ring seems detrimental. Dibutyl tin complexes exhibit IC50 values mostly in the nanomolar range with equal or improved activity compared to the free-base prodigiosene ligand, despite the fact that the general toxicity of such tin complexes is demonstrably lower than that of the free-bases.

  12. In vitro antimalarial and xanthine oxidase inhibition of 2-Aminoanthraquinone.

    PubMed

    Rauf, Abdur; Khan, Rehan; Khan, Haroon; Jehan, Noor; Akram, Mohammad; Ahmad, Zarka; Muhammad, Naveed; Farooq, Umar; Khan, Ajmal

    2016-03-01

    In the present research study 2-Aminoanthraquinone were scrutinized for their antimalarial and Xanthine oxidase inhibitor potential. It demonstrated marked concentration dependent antimalarial activity with maximum effect of 89.06% and with IC50 of 34.17 µM. Regarding Xanthine oxidase inhibitor activity, it evoked significant effect with 57.45% activity with IC50 value of 81.57.19 μM. In conclusion, 2-Aminoanthraquinone showed potent antimalarial and xanthine oxidase inhibitory activity. PMID:27087090

  13. Naturally occurring cobalamins have antimalarial activity.

    PubMed

    Chemaly, Susan M; Chen, Chien-Teng; van Zyl, Robyn L

    2007-05-01

    The acquisition of resistance by malaria parasites towards existing antimalarials has necessitated the development of new chemotherapeutic agents. The effect of vitamin B(12) derivatives on the formation of beta-haematin (synthetic haemozoin) was determined under conditions similar to those in the parasitic food vacuole (using chloroquine, a known inhibitor of haemozoin formation for comparison). Adenosylcobalamin (Ado-cbl), methylcobalamin (CH(3)-cbl) and aquocobalamin (H(2)O-cbl) were approximately forty times more effective inhibitors of beta-haematin formation than chloroquine, cyanocobalamin (CN-cbl) was slightly more inhibitory than chloroquine, while dicyanocobinamide had no effect. It is proposed that the cobalamins exert their inhibitory effect on beta-haematin formation by pi-interactions of their corrin ring with the Fe(III)-protoporphyrin ring and by hydrogen-bonding using their 5,6-dimethylbenzimidazole/ribose/sugar side-chain. The antimalarial activity for the cobalamins (Ado-cbl>CH(3)-cbl>H(2)O-cbl>CN-cbl) was found to be less than that for chloroquine or quinine. Ado-cbl, CH(3)-cbl and CN-cbl do not accumulate in the parasite food vacuole by pH trapping, but H(2)O-cbl does. Unlike humans, the malaria parasite has only one enzyme that uses cobalamin as a cofactor, namely methionine synthase, which is important for growth and metabolism. Thus cobalamins in very small amounts are necessary for Plasmodium falciparum growth but in larger amounts they display antimalarial properties. PMID:17343914

  14. Evaluation of the ex vivo antimalarial activity of organotin (IV) ethylphenyldithiocarbamate on erythrocytes infected with Plasmodium berghei NK 65.

    PubMed

    Awang, Normah; Jumat, Hafizah; Ishak, Shafariatul Akmar; Kamaludin, Nurul Farahana

    2014-06-01

    Malaria is the most destructive and dangerous parasitic disease. The commonness of this disease is getting worse mainly due to the increasing resistance of Plasmodium falciparum against antimalarial drugs. Therefore, the search for new antimalarial drug is urgently needed. This study was carried out to evaluate the effects of dibutyltin (IV) ethylphenyldithiocarbamate (DBEP), diphenyltin (IV) ethylphenyldithiocarbamate (DPEP) and triphenyltin (IV) ethylphenyldithiocarbamate (TPEP) compounds as antimalarial agents. These compounds were evaluated against erythrocytes infected with Plasmodium berghei NK65 via ex vivo. Organotin (IV) ethylphenyldithiocarbamate, [R(n)Sn(C9H10NS2)(4-n)] with R = C4H9 and C6H5 for n = 2; R = C6H5 for n = 3 is chemically synthesised for its potential activities. pLDH assay was employed for determination of the concentration that inhibited 50% of the Plasmodium's activity (IC50) after 24 h treatment at concentration range of 10-0.0000001 mg mL(-1). Plasmodium berghei NK65 was cultured in vitro to determine the different morphology of trophozoite and schizont. Only DPEP and TPEP compounds have antimalarial activity towards P. berghei NK65 at IC50 0.094±0.011 and 0.892±0.088 mg mL(-1), respectively. The IC50 of DPEP and TPEP were lowest at 30% parasitemia with IC50 0.001±0.00009 and 0.0009±0.0001 mg mL(-1), respectively. In vitro culture showed that TPEP was effective towards P. berghei NK65 in trophozoite and schizont morphology with IC50 0.0001±0.00005 and 0.00009±0.00003 μg mL(-1), respectively. In conclusion, DPEP and TPEP have antimalarial effect on erythrocytes infected with P. berghei NK65 and have potential as antimalarial and schizonticidal agents. PMID:26035957

  15. Aspidosperma species as sources of antimalarials. Part III. A review of traditional use and antimalarial activity.

    PubMed

    de Paula, Renata Cristina; Dolabela, Maria Fâni; de Oliveira, Alaíde Braga

    2014-03-01

    Several plant species belonging to the genus Aspidosperma are traditionally used in Brazil and other Meso- and South American countries for the treatment of malaria and fevers. These traditional uses were motivation for this review. A literature survey completed for this review has identified scientific bibliographical references to the use of 24 Aspidosperma species to treat malaria/fevers and to 19 species that have had their extracts and/or alkaloids evaluated, with good results, for in vitro and/or in vivo antimalarial activity. Indole alkaloids are typical constituents of Aspidosperma species. However, only 20 out of more than 200 known indole alkaloids isolated from this genus have been assayed for antimalarial activity. These data support the potential of Aspidosperma species as sources of antimalarials and the importance of research aimed at validating their use in the treatment of human malaria.

  16. The counterfeit anti-malarial is a crime against humanity: a systematic review of the scientific evidence

    PubMed Central

    2014-01-01

    Background The counterfeiting of anti-malarials represents a form of attack on global public health in which fake and substandard anti-malarials serve as de facto weapons of mass destruction, particularly in resource-constrained endemic settings, where malaria causes nearly 660,000 preventable deaths and threatens millions of lives annually. It has been estimated that fake anti-malarials contribute to nearly 450,000 preventable deaths every year. This crime against humanity is often underestimated or ignored. This study attempts to describe and characterize the direct and indirect effects of counterfeit anti-malarials on public health, clinical care and socio-economic conditions. Methods A search was performed using key databases, WHO documents, and English language search engines. Of 262 potential articles that were identified using a fixed set of criteria, a convenience sample of 105 appropriate articles was selected for this review. Results Artemisinin-based combination therapy (ACT) is an important tool in the fight against malaria, but a sizable number of patients are unable to afford to this first-line treatment. Consequently, patients tend to procure cheaper anti-malarials, which may be fake or substandard. Forensic palynology reveals that counterfeits originate in Asia. Fragile drug regulations, ineffective law-enforcement agencies and corruption further burden ailing healthcare facilities. Substandard/fake anti-malarials can cause (a) economic sabotage; (b) therapeutic failure; (c) increased risk of the emergence and spread of resistant strains of Plasmodium falciparum and Plasmodium vivax; (d) an undermining of trust/confidence in healthcare stakeholders/systems; and, (e) serious side effects or death. Conclusion Combating counterfeit anti-malarials is a complex task due to limited resources and poor techniques for the detection and identification of fake anti-malarials. This situation calls for sustainable, global, scientific research and policy change

  17. [Progress in researches on molecular markers of Plasmodium falciparum drug resistance].

    PubMed

    Zhang, Mei-hua; Lu, Feng; Cao, Jun; Gao, Qi

    2015-06-01

    Effective chemotherapy is the mainstay of malaria control. However, it is undergoing the serious threat by resis- tance of falciparum malaria to antimalarial drugs. In recent years, with the development of molecular biology technology, molec- ular markers have been widely used to monitor antimalarial drug resistance. This paper reviews the researches on the common molecular markers related to Plasmodiumfalciparum drug resistance.

  18. Exploring the Molecular Basis of Qo bc1 Complex Inhibitors Activity to Find Novel Antimalarials Hits.

    PubMed

    Carrasco, Marta P; Gut, Jiri; Rodrigues, Tiago; Ribeiro, Maria H L; Lopes, Francisca; Rosenthal, Philip J; Moreira, Rui; Dos Santos, Daniel J V A

    2013-07-01

    Cytochrome bc1 complex is a crucial element in the mitochondrial respiratory chain, being indispensable for the survival of several species of Plasmodia that cause malaria and, therefore, it is a promising target for antimalarial drug development. We report a molecular docking study building on the most recently obtained X-ray structure of the Saccharomyces cerevisiae bc1 complex (PDB code: 3CX5) using several reported inhibitors with experimentally determined IC50 values against the Plasmodium falciparum bc1 complex. We produced a molecular docking model that correlated the calculated binding free energy with the experimental inhibitory activity of each compound. This Qo model was used to search the drug-like database included in the MOE package for novel potential bc1 complex inhibitors. Twenty three compounds were chosen to be tested for their antimalarial activity and four of these compounds demonstrated activity against the chloroquine-resistant W2 strain of P. falciparum. The most active compounds were also active against the atovaquone-resistant P. falciparum FCR3 strain and S. cerevisiae. Our study suggests the validity of the yeast bc1 complex structure as a model for the discovery of new antimalarial hits.

  19. Intervention to Promote Patients' Adherence to Antimalarial Medication: A Systematic Review

    PubMed Central

    Fuangchan, Anjana; Dhippayom, Teerapon; Kongkaew, Chuenjid

    2014-01-01

    Non-adherence as a major contributor to poor treatment outcomes. This study aimed to explore the effectiveness of existing interventions promoting adherence to antimalarial drugs by systematic review. The following databases were used to identify potential articles: MEDLINE, EMBASE, the Cochrane CENTRAL, and CINAHL (through March 2013). From 1,813 potential papers identified, 16 studies met the selection criteria comprising 9,247 patients. Interventions were classified as packaging aids, visual media, combined visual media and verbal information, community education, medication supervision, and convenient regimen. These interventions were shown to increase adherence to antimalarial drugs (median relative risk = 1.4, interquartile range 1.2–2.0). Although a most effective intervention did not emerge, community education and visual media/verbal information combinations may well have most potential to improve adherence to antimalarial medication. These interventions should be implemented in combination to optimize their beneficial effects. The current understanding on improved adherence would facilitate to contain outbreaks of malaria cost effectively. PMID:24166045

  20. Pyrazoleamide compounds are potent antimalarials that target Na+ homeostasis in intraerythrocytic Plasmodium falciparum.

    PubMed

    Vaidya, Akhil B; Morrisey, Joanne M; Zhang, Zhongsheng; Das, Sudipta; Daly, Thomas M; Otto, Thomas D; Spillman, Natalie J; Wyvratt, Matthew; Siegl, Peter; Marfurt, Jutta; Wirjanata, Grennady; Sebayang, Boni F; Price, Ric N; Chatterjee, Arnab; Nagle, Advait; Stasiak, Marcin; Charman, Susan A; Angulo-Barturen, Iñigo; Ferrer, Santiago; Belén Jiménez-Díaz, María; Martínez, María Santos; Gamo, Francisco Javier; Avery, Vicky M; Ruecker, Andrea; Delves, Michael; Kirk, Kiaran; Berriman, Matthew; Kortagere, Sandhya; Burrows, Jeremy; Fan, Erkang; Bergman, Lawrence W

    2014-01-01

    The quest for new antimalarial drugs, especially those with novel modes of action, is essential in the face of emerging drug-resistant parasites. Here we describe a new chemical class of molecules, pyrazoleamides, with potent activity against human malaria parasites and showing remarkably rapid parasite clearance in an in vivo model. Investigations involving pyrazoleamide-resistant parasites, whole-genome sequencing and gene transfers reveal that mutations in two proteins, a calcium-dependent protein kinase (PfCDPK5) and a P-type cation-ATPase (PfATP4), are necessary to impart full resistance to these compounds. A pyrazoleamide compound causes a rapid disruption of Na(+) regulation in blood-stage Plasmodium falciparum parasites. Similar effect on Na(+) homeostasis was recently reported for spiroindolones, which are antimalarials of a chemical class quite distinct from pyrazoleamides. Our results reveal that disruption of Na(+) homeostasis in malaria parasites is a promising mode of antimalarial action mediated by at least two distinct chemical classes. PMID:25422853

  1. Pyrazoleamide compounds are potent antimalarials that target Na+ homeostasis in intraerythrocytic Plasmodium falciparum.

    PubMed

    Vaidya, Akhil B; Morrisey, Joanne M; Zhang, Zhongsheng; Das, Sudipta; Daly, Thomas M; Otto, Thomas D; Spillman, Natalie J; Wyvratt, Matthew; Siegl, Peter; Marfurt, Jutta; Wirjanata, Grennady; Sebayang, Boni F; Price, Ric N; Chatterjee, Arnab; Nagle, Advait; Stasiak, Marcin; Charman, Susan A; Angulo-Barturen, Iñigo; Ferrer, Santiago; Belén Jiménez-Díaz, María; Martínez, María Santos; Gamo, Francisco Javier; Avery, Vicky M; Ruecker, Andrea; Delves, Michael; Kirk, Kiaran; Berriman, Matthew; Kortagere, Sandhya; Burrows, Jeremy; Fan, Erkang; Bergman, Lawrence W

    2014-01-01

    The quest for new antimalarial drugs, especially those with novel modes of action, is essential in the face of emerging drug-resistant parasites. Here we describe a new chemical class of molecules, pyrazoleamides, with potent activity against human malaria parasites and showing remarkably rapid parasite clearance in an in vivo model. Investigations involving pyrazoleamide-resistant parasites, whole-genome sequencing and gene transfers reveal that mutations in two proteins, a calcium-dependent protein kinase (PfCDPK5) and a P-type cation-ATPase (PfATP4), are necessary to impart full resistance to these compounds. A pyrazoleamide compound causes a rapid disruption of Na(+) regulation in blood-stage Plasmodium falciparum parasites. Similar effect on Na(+) homeostasis was recently reported for spiroindolones, which are antimalarials of a chemical class quite distinct from pyrazoleamides. Our results reveal that disruption of Na(+) homeostasis in malaria parasites is a promising mode of antimalarial action mediated by at least two distinct chemical classes.

  2. Synthesis, characterization and in vitro evaluation of novel enantiomerically-pure sulphonamide antimalarials.

    PubMed

    Anusha, Sebastian; Sinha, Ameya; Babu Rajeev, C P; Chu, Trang T T; Mathai, Jessin; Ximei, Huang; Fuchs, Julian E; Shivananju, NanjundaSwamy; Bender, Andreas; Preiser, Peter Rainer; Rangappa, Kanchugarakoppal S; Basappa; Chandramohanadas, Rajesh

    2015-11-21

    Malaria parasites are currently gaining drug-resistance rapidly, across countries and continents. Hence, the discovery and development of novel chemical scaffolds, with superior antimalarial activity remain an important priority, for the developing world. Our report describes the development, characterization and evaluation of novel bepotastine-based sulphonamide antimalarials inhibiting asexual stage development of Plasmodium falciparum parasites in vitro. The screening results showed potent inhibitory activity of a number of novel sulphonamides against P. falciparum at low micromolar concentrations, in particular in late-stage parasite development. Based on computational studies we hypothesize N-myristoyltransferase as the target of the compounds developed here. Our results demonstrate the value of novel bepotastine-based sulphonamide compounds for targeting the asexual developmental stages of P. falciparum. PMID:26347024

  3. Antimalarial quinolines and artemisinin inhibit endocytosis in Plasmodium falciparum.

    PubMed

    Hoppe, Heinrich C; van Schalkwyk, Donelly A; Wiehart, Ursula I M; Meredith, Sandra A; Egan, Joanne; Weber, Brandon W

    2004-07-01

    Endocytosis is a fundamental process of eukaryotic cells and fulfills numerous functions, most notably, that of macromolecular nutrient uptake. Malaria parasites invade red blood cells and during their intracellular development endocytose large amounts of host cytoplasm for digestion in a specialized lysosomal compartment, the food vacuole. In the present study we have examined the effects of artemisinin and the quinoline drugs chloroquine and mefloquine on endocytosis in Plasmodium falciparum. By using novel assays we found that mefloquine and artemisinin inhibit endocytosis of macromolecular tracers by up to 85%, while the latter drug also leads to an accumulation of undigested hemoglobin in the parasite. During 5-h incubations, chloroquine inhibited hemoglobin digestion but had no other significant effect on the endocytic pathway of the parasite, as assessed by electron microscopy, the immunofluorescence localization of hemoglobin, and the distribution of fluorescent and biotinylated dextran tracers. By contrast, when chloroquine was added to late ring stage parasites, followed by a 12-h incubation, macromolecule endocytosis was inhibited by more than 40%. Moreover, there is an accumulation of transport vesicles in the parasite cytosol, possibly due to a disruption in vacuole-vesicle fusion. This fusion block is not observed with mefloquine, artemisinin, quinine, or primaquine but is mimicked by the vacuole alkalinizing agents ammonium chloride and monensin. These results are discussed in the light of present theories regarding the mechanisms of action of the antimalarials and highlight the potential use of drugs in manipulating and studying the endocytic pathway of malaria parasites.

  4. Bilayer Effects of Antimalarial Compounds

    PubMed Central

    Ramsey, Nicole B.; Andersen, Olaf S.

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  5. Understanding Private Sector Antimalarial Distribution Chains: A Cross-Sectional Mixed Methods Study in Six Malaria-Endemic Countries

    PubMed Central

    Palafox, Benjamin; Patouillard, Edith; Tougher, Sarah; Goodman, Catherine; Hanson, Kara; Kleinschmidt, Immo; Rueda, Sergio Torres; Kiefer, Sabine; O’Connell, Kathryn A.; Zinsou, Cyprien; Phok, Sochea; Akulayi, Louis; Arogundade, Ekundayo; Buyungo, Peter; Mpasela, Felton; Chavasse, Desmond

    2014-01-01

    Background Private for-profit outlets are important treatment sources for malaria in most endemic countries. However, these outlets constitute only the last link in a chain of businesses that includes manufacturers, importers and wholesalers, all of which influence the availability, price and quality of antimalarials patients can access. We present evidence on the composition, characteristics and operation of these distribution chains and of the businesses that comprise them in six endemic countries (Benin, Cambodia, Democratic Republic of Congo, Nigeria, Uganda and Zambia). Methods and Findings We conducted nationally representative surveys of antimalarial wholesalers during 2009–2010 using an innovative sampling approach that captured registered and unregistered distribution channels, complemented by in-depth interviews with a range of stakeholders. Antimalarial distribution chains were pyramidal in shape, with antimalarials passing through a maximum of 4–6 steps between manufacturer and retailer; however, most likely pass through 2–3 steps. Less efficacious non-artemisinin therapies (e.g. chloroquine) dominated weekly sales volumes among African wholesalers, while volumes for more efficacious artemisinin-based combination therapies (ACTs) were many times smaller. ACT sales predominated only in Cambodia. In all countries, consumer demand was the principal consideration when selecting products to stock. Selling prices and reputation were key considerations regarding supplier choice. Business practices varied across countries, with large differences in the proportions of wholesalers offering credit and delivery services to customers, and the types of distribution models adopted by businesses. Regulatory compliance also varied across countries, particularly with respect to licensing. The proportion of wholesalers possessing any up-to-date licence from national regulators was lowest in Benin and Nigeria, where vendors in traditional markets are important

  6. 76 FR 50741 - 2011 Parenteral Drug Association/Food and Drug Administration Joint Public Conference; Quality...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... Administration Joint Public Conference; Quality and Compliance in Today's Regulatory Enforcement Environment... entitled ``Quality and Compliance in Today's Regulatory Enforcement Environment.'' The conference will span... practices, including: Accountability in a Global Environment--Enforcement and Supply Chain Office...

  7. Are Patent Medicine Vendors Effective Agents in Malaria Control? Using Lot Quality Assurance Sampling to Assess Quality of Practice in Jigawa, Nigeria

    PubMed Central

    Berendes, Sima; Adeyemi, Olusegun; Oladele, Edward Adekola; Oresanya, Olusola Bukola; Okoh, Festus; Valadez, Joseph J.

    2012-01-01

    Background Patent medicine vendors (PMV) provide antimalarial treatment and care throughout Sub-Saharan Africa, and can play an important role in the fight against malaria. Their close-to-client infrastructure could enable lifesaving artemisinin-based combination therapy (ACT) to reach patients in time. However, systematic assessments of drug sellers’ performance quality are crucial if their role is to be managed within the health system. Lot quality assurance sampling (LQAS) could be an efficient method to monitor and evaluate PMV practice, but has so far never been used for this purpose. Methods In support of the Nigeria Malaria Booster Program we assessed PMV practices in three Senatorial Districts (SDs) of Jigawa, Nigeria. A two-stage LQAS assessed whether at least 80% of PMV stores in SDs used national treatment guidelines. Acceptable sampling errors were set in consultation with government officials (alpha and beta <0.10). The hypergeometric formula determined sample sizes and cut-off values for SDs. A structured assessment tool identified high and low performing SDs for quality of care indicators. Findings Drug vendors performed poorly in all SDs of Jigawa for all indicators. For example, all SDs failed for stocking and selling first-line antimalarials. PMV sold no longer recommended antimalarials, such as Chloroquine, Sulfadoxine-Pyrimethamine and oral Artesunate monotherapy. Most PMV were ignorant of and lacked training about new treatment guidelines that had endorsed ACTs as first-line treatment for uncomplicated malaria. Conclusion There is urgent need to regularly monitor and improve the availability and quality of malaria treatment provided by medicine sellers in Nigeria; the irrational use of antimalarials in the ACT era revealed in this study bears a high risk of economic loss, death and development of drug resistance. LQAS has been shown to be a suitable method for monitoring malaria-related indicators among PMV, and should be applied in Nigeria

  8. Plasmodium falciparum Thioredoxin Reductase (PfTrxR) and Its Role as a Target for New Antimalarial Discovery.

    PubMed

    McCarty, Sara E; Schellenberger, Amanda; Goodwin, Douglas C; Fuanta, Ngolui Rene; Tekwani, Babu L; Calderón, Angela I

    2015-01-01

    The growing resistance to current antimalarial drugs is a major concern for global public health. The pressing need for new antimalarials has led to an increase in research focused on the Plasmodium parasites that cause human malaria. Thioredoxin reductase (TrxR), an enzyme needed to maintain redox equilibrium in Plasmodium species, is a promising target for new antimalarials. This review paper provides an overview of the structure and function of TrxR, discusses similarities and differences between the thioredoxin reductases (TrxRs) of different Plasmodium species and the human forms of the enzyme, gives an overview of modeling Plasmodium infections in animals, and suggests the role of Trx functions in antimalarial drug resistance. TrxR of Plasmodium falciparum is a central focus of this paper since it is the only Plasmodium TrxR that has been crystallized and P. falciparum is the species that causes most malaria cases. It is anticipated that the information summarized here will give insight and stimulate new directions in which research might be most beneficial.

  9. Antimalarial activities of medicinal plants and herbal formulations used in Thai traditional medicine.

    PubMed

    Thiengsusuk, Artitaya; Chaijaroenkul, Wanna; Na-Bangchang, Kesara

    2013-04-01

    Malaria is one of the world's leading killer infectious diseases with high incidence and morbidity. The problem of multidrug-resistant Plasmodium falciparum has been aggravating particularly in Southeast Asia. Therefore, development of new potential antimalarial drugs is urgently required. The present study aimed to investigate antimalarial activities of a total of 27 medicinal plants and 5 herbal formulations used in Thai traditional medicine against chloroquine-resistant (K1) and chloroquine-sensitive (3D7) P. falciparum clones. Antimalarial activity of the ethanolic extracts of all plants/herbal formulations against K1 and 3D7 P. falciparum clones was assessed using SYBR Green I-based assay. All plants were initially screened at the concentration of 50 μg/ml to select the candidate plants that inhibited malaria growth by ≥50%. Each candidate plant was further assessed for the IC50 value (concentration that inhibits malaria growth by 50%) to select the potential plants. Selectivity index (SI) of each extract was determined from the IC50 ratio obtained from human renal epithelial cell and K1 or 3D7 P. falciparum clone. The ethanolic extracts from 19 medicinal plants/herbal formulation exhibited promising activity against both K1 and 3D7 clones of P. falciparum with survival of less than 50% at the concentration of 50 μg/ml. Among these, the extracts from the eight medicinal plants (Plumbago indica Linn., Garcinia mangostana Linn., Dracaena loureiri Gagnep., Dioscorea membranacea Pierre., Artemisia annua Linn., Piper chaba Hunt., Myristica fragrans Houtt., Kaempferia galanga Linn.) and two herbal formulations (Benjakul Formulation 1 and Pra-Sa-Prao-Yhai Formulation) showed potent antimalarial activity with median range IC50 values of less than 10 μg/ml against K1 or 3D7 P. falciparum clone or both. All except G. mangostana Linn. and A. annua Linn. showed high selective antimalarial activity against both clones with SI>10. Further studies on antimalarial

  10. An antimalarial stilbene from Artocarpus integer.

    PubMed

    Boonlaksiri, C; Oonanant, W; Kongsaeree, P; Kittakoop, P; Tanticharoen, M; Thebtaranonth, Y

    2000-06-01

    Antimalarial activity-guided study of the aerial parts of Artocarpus integer led to the isolation of the prenylated stilbene, trans-4-(3-methyl-E-but-1-enyl)-3,5,2',4'-tetrahydroxystilbene with an EC50 of 1.7 micrograms/ml against Plasmodium falciparum in culture. The known stilbenes, trans-4-isopentenyl-3,5,2',4'-tetrahydroxystilbene and 4-methoxy-2,2-dimethyl-6-(2-(2,4-dihydroxy)phenyl-trans-ethenyl)chromene , were also isolated. Structures of these compounds were deduced on the basis of their spectral data.

  11. 21 CFR 212.20 - What activities must I perform to ensure drug quality?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... identity, strength, quality, and purity of a PET drug. You must demonstrate that any change does not... the requirements of the act as to safety and has the identity and strength, and meets the quality and... finished dosage forms to ensure compliance with procedures and specifications affecting the...

  12. Does price reveal poor-quality drugs? Evidence from 17 countries.

    PubMed

    Bate, Roger; Jin, Ginger Zhe; Mathur, Aparna

    2011-12-01

    Focusing on 8 drug types on the WHO-approved medicine list, we constructed an original dataset of 899 drug samples from 17 low- and median-income countries and tested them for visual appearance, disintegration, and analyzed their ingredients by chromatography and spectrometry. Fifteen percent of the samples fail at least one test and can be considered substandard. After controlling for local factors, we find that failing drugs are priced 13.6-18.7% lower than non-failing drugs but the signaling effect of price is far from complete, especially for non-innovator brands. The look of the pharmacy, as assessed by our covert shoppers, is weakly correlated with the results of quality tests. These findings suggest that consumers are likely to suspect low quality from market price, non-innovator brand and the look of the pharmacy, but none of these signals can perfectly identify substandard and counterfeit drugs.

  13. Pharmacokinetic and Pharmacodynamic Considerations in Antimalarial Dose Optimization

    PubMed Central

    2013-01-01

    Antimalarial drugs have usually been first deployed in areas of malaria endemicity at doses which were too low, particularly for high-risk groups such as young children and pregnant women. This may accelerate the emergence and spread of resistance, thereby shortening the useful life of the drug, but it is an inevitable consequence of the current imprecise method of dose finding. An alternative approach to dose finding is suggested in which phase 2 studies concentrate initially on pharmacokinetic-pharmacodynamic (PK-PD) characterization and in vivo calibration of in vitro susceptibility information. PD assessment is facilitated in malaria because serial parasite densities are readily assessed by microscopy, and at low densities by quantitative PCR, so that initial therapeutic responses can be quantitated accurately. If the in vivo MIC could be characterized early in phase 2 studies, it would provide a sound basis for the choice of dose in all target populations in subsequent combination treatments. Population PK assessments in phase 2b and phase 3 studies which characterize PK differences between different age groups, clinical disease states, and human populations can then be combined with the PK-PD observations to provide a sound evidence base for dose recommendations in different target groups. PMID:24002099

  14. Prescription drugs in nursing homes: managing costs and quality in a complex environment.

    PubMed

    Mendelson, Dan; Ramchand, Rajeev; Abramson, Richard; Tumlinson, Anne

    2002-11-12

    This brief provides a description of prescription drug use in nursing homes and a summary of current policy issues in this area. The brief first profiles the nursing home pharmaceutical market, outlining the major trends in demographics and drug utilization, the supply chain by which drugs go from manufacturers to pharmacies to nursing home residents, and the alternative arrangements by which prescription drugs in nursing homes are financed. The brief then provides a synopsis of current policy issues, focusing in turn on cost containment and quality improvement initiatives.

  15. Using genetic methods to define the targets of compounds with antimalarial activity

    PubMed Central

    Flannery, Erika L.; Fidock, David A.; Winzeler, Elizabeth A.

    2013-01-01

    Although phenotypic cellular screening has been used to drive antimalarial drug discovery in recent years, in some cases target-based drug discovery remains more attractive. This is especially true when appropriate high-throughput cellular assays are lacking, as is the case for drug discovery efforts that aim to provide a replacement for primaquine (4-N-(6-methoxyquinolin-8-yl)pentane-1,4-diamine), the only drug that can block Plasmodium transmission to Anopheles mosquitoes and eliminate liver-stage hypnozoites. At present, however, there are no known chemically validated parasite protein targets that are important in all Plasmodium parasite developmental stages and that can be used in traditional biochemical compound screens. We propose that a plethora of novel, chemically validated, cross-stage antimalarial targets still remain to be discovered from the ~5,500 proteins encoded by the Plasmodium genomes. Here we discuss how in vitro evolution of drug-resistant strains of Plasmodium falciparum and subsequent whole-genome analysis can be used to find the targets of some of the many compounds discovered in whole-cell phenotypic screens. PMID:23927658

  16. Antimalarial action of artesunate involves DNA damage mediated by reactive oxygen species.

    PubMed

    Gopalakrishnan, Anusha M; Kumar, Nirbhay

    2015-01-01

    Artemisinin-based combination therapy (ACT) is the recommended first-line treatment for Plasmodium falciparum malaria. It has been suggested that the cytotoxic effect of artemisinin is mediated by free radicals followed by the alkylation of P. falciparum proteins. The endoperoxide bridge, the active moiety of artemisinin derivatives, is cleaved in the presence of ferrous iron, generating reactive oxygen species (ROS) and other free radicals. However, the emergence of resistance to artemisinin in P. falciparum underscores the need for new insights into the molecular mechanisms of antimalarial activity of artemisinin. Here we show that artesunate (ART) induces DNA double-strand breaks in P. falciparum in a physiologically relevant dose- and time-dependent manner. DNA damage induced by ART was accompanied by an increase in the intracellular ROS level in the parasites. Mannitol, a ROS scavenger, reversed the cytotoxic effect of ART and reduced DNA damage, and modulation of glutathione (GSH) levels was found to impact ROS and DNA damage induced by ART. Accumulation of ROS, increased DNA damage, and the resulting antiparasite effect suggest a causal relationship between ROS, DNA damage, and parasite death. Finally, we also show that ART-induced ROS production involves a potential role for NADPH oxidase, an enzyme involved in the production of superoxide anions. Our results with P. falciparum provide novel insights into previously unknown molecular mechanisms underlying the antimalarial activity of artemisinin derivatives and may help in the design of next-generation antimalarial drugs against the most virulent Plasmodium species.

  17. Characterization of PfTrxR inhibitors using antimalarial assays and in silico techniques

    PubMed Central

    2013-01-01

    Background The compounds 1,4-napthoquinone (1,4-NQ), bis-(2,4-dinitrophenyl)sulfide (2,4-DNPS), 4-nitrobenzothiadiazole (4-NBT), 3-dimethylaminopropiophenone (3-DAP) and menadione (MD) were tested for antimalarial activity against both chloroquine (CQ)-sensitive (D6) and chloroquine (CQ)-resistant (W2) strains of Plasmodium falciparum through an in vitro assay and also for analysis of non-covalent interactions with P. falciparum thioredoxin reductase (PfTrxR) through in silico docking studies. Results The inhibitors of PfTrxR namely, 1,4-NQ, 4-NBT and MD displayed significant antimalarial activity with IC50 values of < 20 μM and toxicity against 3T3 cell line. 2,4-DNPS was only moderately active. In silico docking analysis of these compounds with PfTrxR revealed that 2,4-DNPS, 4-NBT and MD interact non-covalently with the intersubunit region of the enzyme. Conclusions In this study, tools for the identification of PfTrxR inhibitors using phenotyphic screening and docking studies have been validated for their potential use for antimalarial drug discovery project. PMID:24209891

  18. Novel 4-Aminoquinoline-Pyrimidine Based Hybrids with Improved in Vitro and in Vivo Antimalarial Activity

    PubMed Central

    2012-01-01

    A class of hybrid molecules consisting of 4-aminoquinoline and pyrimidine were synthesized and tested for antimalarial activity against both chloroquine (CQ)-sensitive (D6) and chloroquine (CQ)-resistant (W2) strains of Plasmodium falciparum through an in vitro assay. Eleven hybrids showed better antimalarial activity against both CQ-sensitive and CQ-resistant strains of P. falciparum in comparison to standard drug CQ. Four molecules were more potent (7–8-fold) than CQ in D6 strain, and eight molecules were found to be 5–25-fold more active against resistant strain (W2). Several compounds did not show any cytotoxicity up to a high concentration (60 μM), others exhibited mild toxicities, but the selective index for the antimalarial activity was very high for most of these hybrids. Two compounds selected for in vivo evaluation have shown excellent activity (po) in a mouse model of Plasmodium berghei without any apparent toxicity. The X-ray crystal structure of one of the compounds was also determined. PMID:24900509

  19. Antimalarial remedies in French Guiana: a knowledge attitudes and practices study.

    PubMed

    Vigneron, M; Deparis, X; Deharo, E; Bourdy, G

    2005-04-26

    A "knowledge attitudes and practices" study about malaria treatments was undertaken in French Guiana, along with an ethnopharmacological study. One hundred and seventeen people from five different groups and nationalities (Creole, Palikur, Galibi, Brazilian, and European) answered the questionnaire. The results were analysed using univariate and multivariate statistical analysis. First, we evaluated the overall knowledge about malaria from the interviewed people. According to bio-medical concepts, we noticed that they have a good knowledge of this illness. Secondly, we studied the treatment used by sick people during their last malaria attack. We demonstrated that, although bio-medical treatment is available in this area, people use both modern drugs and traditional remedies. Finally, preventive attitudes have been examined. One-third of the interviewed people drink regularly some herbal remedy to prevent febrile illnesses and malaria, thus displaying a strong concern about this disease. The ethnopharmacological study highlighted the frequent use of traditional remedies, along with their mode of preparation and administration. A total of 34 different species (both from flora and fauna) have been registered as antimalarial. Twenty-seven are used for curative purposes, 20 as preventive and 13 of them are used for both purposes. Quassia amara (Simaroubaceae) whose antimalarial activity has already been demonstrated was the species most frequently used as antimalarial for curative and preventive purposes.

  20. In vivo antimalarial activity of the endophytic actinobacteria, Streptomyces SUK 10.

    PubMed

    Baba, Mohd Shukri; Zin, Noraziah Mohamad; Hassan, Zainal Abidin Abu; Latip, Jalifah; Pethick, Florence; Hunter, Iain S; Edrada-Ebel, RuAngelie; Herron, Paul R

    2015-12-01

    Endophytic bacteria, such as Streptomyces, have the potential to act as a source for novel bioactive molecules with medicinal properties. The present study was aimed at assessing the antimalarial activity of crude extract isolated from various strains of actinobacteria living endophytically in some Malaysian medicinal plants. Using the four day suppression test method on male ICR strain mice, compounds produced from three strains of Streptomyces (SUK8, SUK10, and SUK27) were tested in vivo against Plasmodium berghei PZZ1/100 in an antimalarial screen using crude extracts at four different concentrations. One of these extracts, isolated from Streptomyces SUK10 obtained from the bark of Shorea ovalis tree, showed inhibition of the test organism and was further tested against P. berghei-infected mice for antimalarial activity at different concentrations. There was a positive relationship between the survival of the infected mouse group treated with 50 µg/kg body weight (bw) of ethyl acetate-SUK10 crude extract and the ability to inhibit the parasites growth. The parasite inhibition percentage for this group showed that 50% of the mice survived for more than 90 days after infection with the parasite. The nucleotide sequence and phylogenetic tree suggested that Streptomyces SUK10 may constitute a new species within the Streptomyces genus. As part of the drug discovery process, these promising finding may contribute to the medicinal and pharmaceutical field for malarial treatment. PMID:26626355

  1. Malaria and antimalarial plants in Roraima, Brazil.

    PubMed

    Milliken, W

    1997-01-01

    One of the numerous problems created by the gold rush which took place in northern Brazil (Roraima State) at the end of the 1980s was a severe epidemic of malaria amongst the indigenous peoples of the region. Worst hit were the Yanomami Indians, who had lived in almost total isolation prior to this event. The problem has been exacerbated by the development of chloroquine-resistant strains of Plasmodium falciparum. In an effort to identify viable alternatives to dependence on western medicine for malaria treatment, a survey was carried out on the local plant species (wild and cultivated) used for this purpose in Roraima. Fieldwork was carried out amongst seven indigenous peoples, as well as with the non-indigenous settlers. Over 90 species were collected, many of which have been cited as used for treatment of malaria and fevers elsewhere. Knowledge of antimalarial plants was found to vary greatly between the communities, and in some cases there was evidence of recent experimentation. Initial screening of plant extracts has shown a high incidence of significant antimalarial activity amongst the species collected. PMID:9204719

  2. Antimalarial and cytotoxic properties of Chukrasia tabularis A. Juss and Turraea vogelii Hook F. Ex. Benth.

    PubMed

    Ogbole, Omonike O; Saka, Yusuf A; Fasinu, Pius S; Fadare, Adenike A; Ajaiyeoba, Edith O

    2016-04-01

    Malaria, caused by plasmodium parasite, is at the moment the highest cause of morbidity and mortality in the tropics. Recently, there is increasing efforts to develop more potent antimalarials from plant sources that will have little or no adverse effects. This study is aimed at investigating the in vivo mice antimalarial and in vitro antiplasmodial effects of two Meliaceae plants commonly used in Nigerian ethnomedicine as part of recipe for treating malaria infection: Chukrasia tabularis and Turraea vogelii. Hot water decoction and methanol extract of both plants were evaluated for their antimalarial activity in vivo using the mice model assay and in vitro using the parasite lactate dehydrogenase (pLDH) assay. The extracts were also assessed for toxicity with brine shrimp lethality assay and in mammalian cell lines using the neural red assay. The in vivo mice model antimalarial study showed that the methanol extract of the stem bark of C. tabularis exhibited the highest % chemosuppression (83.65 ± 0.66) at the highest dosage administered (800 mg/kg) when compared with chloroquine diphosphate, the standard reference drug which had a % suppression of 90.36 ± 0.04 (p < 0.05). The in vitro antiplasmodial study indicated that the aqueous extract of the stem bark of C. tabularis displayed good activity against Plasmodium falciparum chloroquine-sensitive (D6) strain (IC50 of 10.739 μg/mL) and chloroquine-resistant (W2) strain. Chloroquine and artemisinin had <0.163 and <0.0264, respectively. PMID:26911147

  3. In vitro antimalarial activity of different extracts of Eremostachys macrophylla Montbr. & Auch.

    PubMed Central

    Asnaashari, Solmaz; Heshmati Afshar, Fariba; Ebrahimi, Atefeh; Bamdad Moghadam, Sedigheh; Delazar, Abbas

    2015-01-01

    Introduction:The risk of drug resistance and the use of medicinal plants in malaria prevention and treatment have led to the search for new antimalarial compounds with natural origin. Methods:In the current study, six extracts with different polarity from aerial parts and rhizomes of Eremostachys macrophylla Montbr. & Auch., were screened for their antimalarial properties by cell-free β-hematin formation assay. Results: Dichloromethane (DCM) extracts of both parts of plant showed significant antimalarial activities with IC50 values of 0.797 ± 0.016 mg/mL in aerial parts and 0.324 ± 0.039 mg/mL in rhizomes compared to positive control (Chloroquine, IC50 = 0.014 ± 0.003 mg/mL, IC90 = 0.163 ± 0.004 mg/mL). Bioactivity-guided fractionation of the most potent part (DCM extract of rhizomes) by vacuum liquid chromatography (VLC) afforded seven fractions. Sixty percent ethyl acetate/n-hexane fraction showed considerable antimalarial activity with IC50 value of 0.047 ± 0.0003 mg/mL. Conclusion: From 6 extracts with different polarity of E. macrophylla,s aerial parts and rhizomes, the DCM extract of both parts were the most active extract in this assay. The preliminary phytochemical study on the VLC fractions of the most potent part persuades us to focus on purifying the active components of these extracts and to conduct further investigation towards in vivo evaluation. PMID:26457251

  4. Quality medicines for the poor: experience of the Delhi programme on rational use of drugs.

    PubMed

    Chaudhury, R Roy; Parameswar, R; Gupta, U; Sharma, S; Tekur, U; Bapna, J S

    2005-03-01

    Prior to 1994, most Delhi hospitals and dispensaries experienced constant shortages of essential medicines. There was erratic prescribing of expensive branded products, frequent complaints about poor drug quality and low patient satisfaction. Delhi took the lead in developing a comprehensive Drug Policy in 1994 and was the only Indian state to have such a comprehensive policy. The policy's main objective is to improve the availability and accessibility of quality essential drugs for all those in need. The Delhi Society for the Promotion of Rational Use of Drugs (DSPRUD), a non-governmental organization, worked in close collaboration with the Delhi Government and with universities to implement various components of the policy. The first Essential Drugs List (EDL) was developed, a centralized pooled procurement system was set up and activities promoting rational use of drugs were initiated. In 1997, the Delhi Programme was designated the INDIA-WHO Essential Drugs Programme by the World Health Organization. The EDL was developed by a committee consisting of a multidisciplinary group of experts using balanced criteria of efficacy, safety, suitability and cost. The first list contained 250 drugs for hospitals and 100 drugs for dispensaries; the list is revised every 2 years. The pooled procurement system, including the rigorous selection of suppliers with a minimum annual threshold turnover and the introduction of Good Manufacturing Practice inspections, resulted in the supply of good quality drugs and in holding down the procurement costs of many drugs. Bulk purchasing of carefully selected essential drugs was estimated to save nearly 30% of the annual drugs bill for the Government of Delhi, savings which were mobilized for procuring more drugs, which in turn improved availability of drugs (more than 80%) at health facilities. Further, training programmes for prescribers led to a positive change in prescribing behaviour, with more than 80% of prescriptions being from

  5. Antimalarial dyes revisited: xanthenes, azines, oxazines, and thiazines.

    PubMed Central

    Vennerstrom, J L; Makler, M T; Angerhofer, C K; Williams, J A

    1995-01-01

    In 1891 Guttmann and Ehrlich (P. Guttmann and P. Ehrlich, Berlin Klin. Wochenschr. 28:953-956, 1891) were the first to report the antimalarial properties of a synthetic, rather than a natural, material when they described the clinical cure of two patients after oral administration of a thiazine dye, methylene blue. Since that time, sporadic reports of the antimalarial properties of several xanthene and azine dyes related to methylene blue have been noted. We report here the results from a reexamination of the antimalarial properties of methylene blue. Janus green B, and three rhodamine dyes and disclose new antimalarial data for 16 commercially available structural analogs of these dyes. The 50% inhibitory concentrations for the chloroquine-susceptible D6 clone and SN isolate and the chloroquine-resistant W2 clone of Plasmodium falciparum were determined by the recently described parasite lactate dehydrogenase enzyme assay. No cross-resistance to chloroquine was observed for any of the dyes. For the 21 dyes tested, no correlation was observed between antimalarial activity and cytotoxicity against KB cells. No correlation between log P (where P is the octanol/water partition coefficient) or relative catalyst efficiency for glucose oxidation and antimalarial activity or cytotoxicity was observed for the dyes as a whole or for the thiazine dyes. The thiazine dyes were the most uniformly potent structural class tested, and among the dyes in this class, methylene blue was notable for both its high antimalarial potency and selectivity. PMID:8593000

  6. Pharmacological effects of primaquine ureas and semicarbazides on the central nervous system in mice and antimalarial activity in vitro.

    PubMed

    Kedzierska, Ewa; Orzelska, Jolanta; Perković, Ivana; Knežević, Danijel; Fidecka, Sylwia; Kaiser, Marcel; Zorc, Branka

    2016-02-01

    New primaquine (PQ) urea and semicarbazide derivatives 1-4 were screened for the first time for central nervous system (CNS) and antimalarial activity. Behavioural tests were performed on mice. In vitro cytotoxicity on L-6 cells and activity against erythrocytic stages of Plasmodium falciparum was determined. Compound 4 inhibited 'head-twitch' responses and decreased body temperature of mice, which suggests some involvement of the serotonergic system. Compound 4 protected mice against clonic seizures and was superior in the antimalarial test. A hybrid of two PQ urea 2 showed a strong antimalarial activity, confirming the previous findings of the high activity of bis(8-aminoquinolines) and other bisantimalarial drugs. All the compounds decreased the locomotor activity of mice, what suggests their weak depressive effects on the CNS, while PQ derivatives 1 and 2 increased amphetamine-induced hyperactivity. None of the compounds impaired coordination, what suggests a lack of their neurotoxicity. All the tested compounds presented an antinociceptive activity in the 'writhing' test. Compounds 3 and 4 were active in nociceptive tests, and those effects were reversed by naloxone. Compound 4 could be a useful lead compound in the development of CNS active agents and antimalarials, whereas compound 3 may be considered as the most promising lead for new antinociceptive agents. PMID:26501210

  7. Contribution of metabolites to P450 inhibition-based drug-drug interactions: scholarship from the drug metabolism leadership group of the innovation and quality consortium metabolite group.

    PubMed

    Yu, Hongbin; Balani, Suresh K; Chen, Weichao; Cui, Donghui; He, Ling; Humphreys, W Griffith; Mao, Jialin; Lai, W George; Lee, Anthony J; Lim, Heng-Keang; MacLauchlin, Christopher; Prakash, Chandra; Surapaneni, Sekhar; Tse, Susanna; Upthagrove, Alana; Walsky, Robert L; Wen, Bo; Zeng, Zhaopie

    2015-04-01

    Recent European Medicines Agency (final) and US Food and Drug Administration (draft) drug interaction guidances proposed that human circulating metabolites should be investigated in vitro for their drug-drug interaction (DDI) potential if present at ≥ 25% of the parent area under the time-concentration curve (AUC) (US Food and Drug Administration) or ≥ 25% of the parent and ≥ 10% of the total drug-related AUC (European Medicines Agency). To examine the application of these regulatory recommendations, a group of scientists, representing 18 pharmaceutical companies of the Drug Metabolism Leadership Group of the Innovation and Quality Consortium, conducted a scholarship to assess the risk of contributions by metabolites to cytochrome P450 (P450) inhibition-based DDIs. The group assessed the risk of having a metabolite as the sole contributor to DDI based on literature data and analysis of the 137 most frequently prescribed drugs, defined structural alerts associated with P450 inhibition/inactivation by metabolites, and analyzed current approaches to trigger in vitro DDI studies for metabolites. The group concluded that the risk of P450 inhibition caused by a metabolite alone is low. Only metabolites from 5 of 137 drugs were likely the sole contributor to the in vivo P450 inhibition-based DDIs. Two recommendations were provided when assessing the need to conduct in vitro P450 inhibition studies for metabolites: 1) consider structural alerts that suggest P450 inhibition potential, and 2) use multiple approaches (e.g., a metabolite cut-off value of 100% of the parent AUC and the R(met) strategy) to predict P450 inhibition-based DDIs caused by metabolites in the clinic.

  8. Contribution of metabolites to P450 inhibition-based drug-drug interactions: scholarship from the drug metabolism leadership group of the innovation and quality consortium metabolite group.

    PubMed

    Yu, Hongbin; Balani, Suresh K; Chen, Weichao; Cui, Donghui; He, Ling; Humphreys, W Griffith; Mao, Jialin; Lai, W George; Lee, Anthony J; Lim, Heng-Keang; MacLauchlin, Christopher; Prakash, Chandra; Surapaneni, Sekhar; Tse, Susanna; Upthagrove, Alana; Walsky, Robert L; Wen, Bo; Zeng, Zhaopie

    2015-04-01

    Recent European Medicines Agency (final) and US Food and Drug Administration (draft) drug interaction guidances proposed that human circulating metabolites should be investigated in vitro for their drug-drug interaction (DDI) potential if present at ≥ 25% of the parent area under the time-concentration curve (AUC) (US Food and Drug Administration) or ≥ 25% of the parent and ≥ 10% of the total drug-related AUC (European Medicines Agency). To examine the application of these regulatory recommendations, a group of scientists, representing 18 pharmaceutical companies of the Drug Metabolism Leadership Group of the Innovation and Quality Consortium, conducted a scholarship to assess the risk of contributions by metabolites to cytochrome P450 (P450) inhibition-based DDIs. The group assessed the risk of having a metabolite as the sole contributor to DDI based on literature data and analysis of the 137 most frequently prescribed drugs, defined structural alerts associated with P450 inhibition/inactivation by metabolites, and analyzed current approaches to trigger in vitro DDI studies for metabolites. The group concluded that the risk of P450 inhibition caused by a metabolite alone is low. Only metabolites from 5 of 137 drugs were likely the sole contributor to the in vivo P450 inhibition-based DDIs. Two recommendations were provided when assessing the need to conduct in vitro P450 inhibition studies for metabolites: 1) consider structural alerts that suggest P450 inhibition potential, and 2) use multiple approaches (e.g., a metabolite cut-off value of 100% of the parent AUC and the R(met) strategy) to predict P450 inhibition-based DDIs caused by metabolites in the clinic. PMID:25655830

  9. Microbial burden of some herbal antimalarials marketed at Elele, Rivers State.

    PubMed

    Tatfeng, Y M; Olama, E H; Ojo, T O

    2010-01-01

    Herbal antimalarials still remain an alternative to our traditional communities who can not afford orthodox antimalarials. This study was aimed at investigating the microbial quality of six herbal antimalarials using standard microbiological methods. Of the six preparations analyzed, "schnapps", palm wine and water were the media of preparation; the water base preparations recorded higher microbial load. The mean microbial load was 159.5 × 10(5) cfu/ml and 217.4 × 10(2)cfu/ml in water and alcohol base preparations respectively. The microbial profile of the preparations showed that the schnapps base preparations were predominantly contaminated with Bacillus sp (Aerobic spore bearers) and Mucor spp. The palm wine preparation harboured Bacillus sp, yeasts and Mucor spp while the water base preparations had several isolates such as Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli 0157H7, Proteus mirabilis, Enterococcus feacalis, Serratia marcensces, Staph. aureus, Bacillus spp and Mucor spp. Conclusively, this study underlines the public health importance of these preparations given the high burden of such human pathogen as Ecoli O157H7, Ps aeruginosa, Stahp aureus, etc. in the preparations. PMID:21304626

  10. Drug-Induced Itch Management.

    PubMed

    Ebata, Toshiya

    2016-01-01

    Drugs may cause itching as a concomitant symptom of drug-induced skin reactions or in the form of pruritus without skin lesions. Drug-induced itch is defined as generalized itching without skin lesions, caused by a drug. Itching associated with drug-induced cholestasis is among the common dermatologic adverse events (dAEs) that induce itching. Some drugs such as opioids, antimalarials, and hydroxyethyl starch are known to induce itching without skin lesions. The clinical features and underlying proposed mechanisms of itching caused by these drugs have been specifically investigated. The recent application of targeted anticancer drugs has increased the survival rate of cancer patients. These new agents cause significant dAEs such as acneiform rashes, dry skin, hand-foot syndrome, paronychia, and itching. Itching is a common side effect of epidermal growth factor receptor inhibitors. Though not life-threatening, these dAEs have a negative impact on a patient's quality of life, leading to dose reduction and possibly less effective cancer therapy. It is important to provide an effective supportive antipruritic treatment without interruption of the administration of these drugs. This chapter concludes by describing basic measures to be taken for diagnosis and treatment of drug-induced itch. The principle of treatment is discontinuation of suspected causative drugs in general except for anticancer medications. In case itching lasts long after drug withdrawal or the causative drug cannot be stopped, vigorous symptomatic antipruritic treatment and specific therapies for different types of drug-induced itch should be undertaken. PMID:27578085

  11. Basigin is a druggable target for host-oriented antimalarial interventions

    PubMed Central

    Zenonos, Zenon A.; Dummler, Sara K.; Müller-Sienerth, Nicole; Chen, Jianzhu; Preiser, Peter R.; Rayner, Julian C.

    2015-01-01

    Plasmodium falciparum is the parasite responsible for the most lethal form of malaria, an infectious disease that causes a large proportion of childhood deaths and poses a significant barrier to socioeconomic development in many countries. Although antimalarial drugs exist, the repeated emergence and spread of drug-resistant parasites limit their useful lifespan. An alternative strategy that could limit the evolution of drug-resistant parasites is to target host factors that are essential and universally required for parasite growth. Host-targeted therapeutics have been successfully applied in other infectious diseases but have never been attempted for malaria. Here, we report the development of a recombinant chimeric antibody (Ab-1) against basigin, an erythrocyte receptor necessary for parasite invasion as a putative antimalarial therapeutic. Ab-1 inhibited the PfRH5-basigin interaction and potently blocked erythrocyte invasion by all parasite strains tested. Importantly, Ab-1 rapidly cleared an established P. falciparum blood-stage infection with no overt toxicity in an in vivo infection model. Collectively, our data demonstrate that antibodies or other therapeutics targeting host basigin could be an effective treatment for patients infected with multi-drug resistant P. falciparum. PMID:26195724

  12. Reemergence of chloroquine (CQ) analogs as multi-targeting antimalarial agents: a review.

    PubMed

    Mushtaque, Md; Shahjahan

    2015-01-27

    Amongst several communicable diseases (CDs), malaria is one of the deadliest parasitic disease all over the world, particularly in African and Asian countries. To curb this menace, numbers of antimalarial agents are being sold as over the counter (OTC) drugs. Chloroquine (CQ) is one of them and is one of the oldest, cheapest, and easily available synthetic agents used to curb malaria. Unfortunately, after the reports of CQ-resistance against different strains of malarial parasite strains worldwide, scientist are continuously modifying the core structure of CQ to get an efficient drug. Interestingly, several new drugs have been emerged in due course having unique and enhanced properties (like dual stage inhibitors, resistance reversing ability etc.) and are ready to enter into the clinical trial. In this course, some new agents have also been discovered which are; though inactive against CQS strain, highly active against CQR strains. The present article describes the role of modification of the core structure of CQ and its effects on the biological activities. Moreover, the attempt has also been made to predict the future prospects of such drugs to reemerge as antimalarial agents. PMID:25461328

  13. Reverse pharmacology for developing an anti-malarial phytomedicine. The example of Argemone mexicana

    PubMed Central

    Simoes-Pires, Claudia; Hostettmann, Kurt; Haouala, Amina; Cuendet, Muriel; Falquet, Jacques; Graz, Bertrand; Christen, Philippe

    2014-01-01

    Classical pharmacology has been the basis for the discovery of new chemical entities with therapeutic effects for decades. In natural product research, compounds are generally tested in vivo only after full in vitro characterization. However drug screening using this methodology is expensive, time-consuming and very often inefficient. Reverse pharmacology, also called bedside-to-bench, is a research approach based on the traditional knowledge and relates to reversing the classical laboratory to clinic pathway to a clinic to laboratory practice. It is a trans-disciplinary approach focused on traditional knowledge, experimental observations and clinical experiences. This paper is an overview of the reverse pharmacology approach applied to the decoction of Argemone mexicana, used as an antimalarial traditional medicine in Mali. A. mexicana appeared as the most effective traditional medicine for the treatment of uncomplicated falciparum malaria in Mali, and the clinical efficacy of the decoction was comparable to artesunate–amodiaquine as previously published. Four stages of the reverse pharmacology process will be described here with a special emphasis on the results for stage 4. Briefly, allocryptopine, protopine and berberine were isolated through bioguided fractionation, and had their identity confirmed by spectroscopic analysis. The three alkaloids showed antiparasitic activity in vitro, of which allocryptopine and protopine were selective towards Plasmodiumfalciparum. Furthermore, the amount of the three active alkaloids in the decoction was determined by quantitative NMR, and preliminary in vivo assays were conducted. On the basis of these results, the reverse pharmacology approach is discussed and further pharmacokinetic studies appear to be necessary in order to determine whether these alkaloids can be considered as phytochemical markers for quality control and standardization of an improved traditional medicine made with this plant. PMID:25516845

  14. Experiences of drug use and ageing: health, quality of life, relationship and service implications

    PubMed Central

    Roe, Brenda; Beynon, Caryl; Pickering, Lucy; Duffy, Paul

    2010-01-01

    roe b., beynon c., pickering l. & duffy p. (2010)Experiences of drug use and ageing: health, quality of life, relationship and service implications. Journal of Advanced Nursing66(9), 1968–1979. Aim This paper is a report of an exploration of older people’s experiences of substance use in the context of ageing, and its impact on health, quality of life, relationships and service use. Background Use of illicit drugs by older people is a neglected policy, research and service provision and is generally perceived as a lifestyle of younger populations. Method A convenience sample of 11 people aged 49–61 years (mean 57 years) in contact with voluntary sector drug treatment services participated in qualitative semi-structured tape-recorded interviews and thematic content analysis was performed. The data were collected in 2008. Findings Drug use can have negative impacts on health status, quality of life, family relationships and social networks that accrue with age. Participants were identified as early or later onset users of drugs due to the impact of life events and relationships. A range of substances had been used currently and throughout their lives, with no single gateway drug identified as a prelude to personal drug careers. Life review and reflection were common, in keeping with ageing populations, along with regret of ever having started to use drugs. Living alone and their accommodation made them more susceptible to social isolation, and they reported experiences of death and dying of their contemporaries and family members earlier than usual in the life course. Conclusion Older people who continue to use drugs and require the support of services for treatment and care are an important emerging population and their specific needs should recognized. PMID:20626477

  15. In vivo antiplasmodial potentials of the combinations of four nigerian antimalarial plants.

    PubMed

    Adebajo, Adeleke Clement; Odediran, Samuel Akintunde; Aliyu, Fatimah Abosede; Nwafor, Paul Alozie; Nwoko, Ndifreke Thomas; Umana, Usenobong Samuel

    2014-01-01

    Various combinations of Nauclea latifolia root, Artocarpus altilis stem bark, Murraya koenigii leaf and Enantia chlorantha stem bark used in African ethnomedicine as decoctions for malaria and fevers, and combinations with standard drugs, were investigated for antiplasmodial activities using Plasmodium berghei berghei-infected mice. The respective prophylactic and curative ED50 values of 189.4 and 174.5 mg/kg for N. latifolia and chemosuppressive ED50 value of 227.2 mg/kg for A. altilis showed that they were the best antimalarial herbal drugs. A 1.6-fold increase of the survival time given by the negative control was elicited by M. koenigii, thereby confirming its curative activity. Pyrimethamine with an ED50 of 0.5 ± 0.1 mg/kg for the prophylactic, and chloroquine with ED50 = 2.2 ± 0.1 and 2.2 ± 0.0 mg/kg for the chemosuppressive and curative tests, respectively, were significantly (p < 0.05) more active. Co-administrations of N. latifolia with the standard drugs significantly reduced their prophylactic, chemosuppressive and curative actions, possibly increasing the parasites' resistance. Binary combinations of N. latifolia or M. koenigii with any of the other plants significantly increased the prophylactic and suppressive activities of their individual plants, respectively. Also, E. chlorantha with A. altilis or N. latifolia enhanced their respective prophylactic or curative activities, making these combinations most beneficial against malaria infections. Combinations of three and four extracts gave varied activities. Hence, the results justified the combinations of ethnomedicinal plants in antimalarial herbal remedies and showed the importance of the three in vivo models in establishing antimalarial activity. PMID:25162955

  16. In vivo antiplasmodial potentials of the combinations of four nigerian antimalarial plants.

    PubMed

    Adebajo, Adeleke Clement; Odediran, Samuel Akintunde; Aliyu, Fatimah Abosede; Nwafor, Paul Alozie; Nwoko, Ndifreke Thomas; Umana, Usenobong Samuel

    2014-01-01

    Various combinations of Nauclea latifolia root, Artocarpus altilis stem bark, Murraya koenigii leaf and Enantia chlorantha stem bark used in African ethnomedicine as decoctions for malaria and fevers, and combinations with standard drugs, were investigated for antiplasmodial activities using Plasmodium berghei berghei-infected mice. The respective prophylactic and curative ED50 values of 189.4 and 174.5 mg/kg for N. latifolia and chemosuppressive ED50 value of 227.2 mg/kg for A. altilis showed that they were the best antimalarial herbal drugs. A 1.6-fold increase of the survival time given by the negative control was elicited by M. koenigii, thereby confirming its curative activity. Pyrimethamine with an ED50 of 0.5 ± 0.1 mg/kg for the prophylactic, and chloroquine with ED50 = 2.2 ± 0.1 and 2.2 ± 0.0 mg/kg for the chemosuppressive and curative tests, respectively, were significantly (p < 0.05) more active. Co-administrations of N. latifolia with the standard drugs significantly reduced their prophylactic, chemosuppressive and curative actions, possibly increasing the parasites' resistance. Binary combinations of N. latifolia or M. koenigii with any of the other plants significantly increased the prophylactic and suppressive activities of their individual plants, respectively. Also, E. chlorantha with A. altilis or N. latifolia enhanced their respective prophylactic or curative activities, making these combinations most beneficial against malaria infections. Combinations of three and four extracts gave varied activities. Hence, the results justified the combinations of ethnomedicinal plants in antimalarial herbal remedies and showed the importance of the three in vivo models in establishing antimalarial activity.

  17. In vitro antimalarial activity and chloroquine potentiating action of two bisbenzylisoquinoline enantiomer alkaloids isolated from Strychnopsis thouarsii and Spirospermum penduliflorum.

    PubMed

    Ratsimamanga-Urverg, S; Rasoanaivo, P; Ramiaramanana, L; Milijaona, R; Rafatro, H; Verdier, F; Rakoto-Ratsimamanga, A; Le Bras, J

    1992-12-01

    The bisbenzylisoquinolines 7-O-demethyltetrandrine and limacine, respectively, isolated from Strychnopsis thouarsii Baill. and Spirospermum penduliflorum Thou. were evaluated for their intrinsic antimalarial activity in vitro and chloroquine potentiating action against the chloroquine-resistant Plasmodium falciparum FCM 29 originating from Cameroon. They both showed significant antiplasmodial potency in vitro with very similar IC50 values of respectively, 740 nM and 789 nM (IC50 = 214 nM for chloroquine used as standard drug), which demonstrated that the stereochemistry of the C-1 and C-1' configuration likely plays a role in the chloroquine potentiating effect of these drugs. If confirmed in vivo, these results may account for the traditional use of the two plants as antimalarials and adjuvant to chloroquine in Madagascan folklore remedies. PMID:1484894

  18. Molecular markers associated with resistance to commonly used antimalarial drugs among Plasmodium falciparum isolates from a malaria-endemic area in Taiz governorate-Yemen during the transmission season.

    PubMed

    Alareqi, Lina M Q; Mahdy, Mohammed A K; Lau, Yee-Ling; Fong, Mun-Yik; Abdul-Ghani, Rashad; Mahmud, Rohela

    2016-10-01

    Since 2005, artesunate (AS) plus sulfadoxine/pyrimethamine (SP) combination has been adopted as the first-line treatment for uncomplicated malaria in Yemen in response to the high level of Plasmodium falciparum resistance to chloroquine (CQ). Therefore, the aim of the present study was to determine the frequency distribution of molecular markers associated with resistance to CQ and AS plus SP combination among P. falciparum isolates from a malaria-endemic area in Taiz governorate, Yemen. Fifty P. falciparum isolates were collected during a cross-sectional study in Mawza district, Taiz, in the period from October 2013 to April 2014. The isolates were investigated for drug resistance-associated molecular markers in five genes, including P. falciparum CQ resistance transporter (pfcrt) 76T and P. falciparum multidrug resistance 1 (pfmdr1) 86Y as markers of resistance to CQ, mutations in the Kelch 13 (K13) propeller domain for resistance to AS, and P. falciparum dihydrofolate reductase (pfdhfr) and P. falciparum dihydropteroate synthase (pfdhps) genes for resistance to SP. Nested polymerase chain reaction was used to amplify target genes in DNA extracts of the isolates followed by restriction fragment length polymorphism for detecting 76T and 86Y mutations in pfcrt and pfmdr1, respectively, and by DNA sequencing for detecting mutations in K13, pfdhfr and pfdhps. All the investigated isolates from Mawza district were harboring the pfcrt 76T mutant and the pfmdr1 N86 wild-type alleles. The pfdhfr 51I/108N double mutant allele was found in 2.2% (1/45) of the isolates; however, no mutations were detected at codons 436, 437, 540, 581 and 613 of pfdhps. All P. falciparum isolates that were successfully sequenced (n=47) showed the K13 Y493, R539, I543 and C580 wild-type alleles. In conclusion, the pfcrt 76T mutant allele is fixed in the study area about six years after the official withdrawal of CQ, possibly indicating its over-the-counter availability and continued use as a

  19. Molecular markers associated with resistance to commonly used antimalarial drugs among Plasmodium falciparum isolates from a malaria-endemic area in Taiz governorate-Yemen during the transmission season.

    PubMed

    Alareqi, Lina M Q; Mahdy, Mohammed A K; Lau, Yee-Ling; Fong, Mun-Yik; Abdul-Ghani, Rashad; Mahmud, Rohela

    2016-10-01

    Since 2005, artesunate (AS) plus sulfadoxine/pyrimethamine (SP) combination has been adopted as the first-line treatment for uncomplicated malaria in Yemen in response to the high level of Plasmodium falciparum resistance to chloroquine (CQ). Therefore, the aim of the present study was to determine the frequency distribution of molecular markers associated with resistance to CQ and AS plus SP combination among P. falciparum isolates from a malaria-endemic area in Taiz governorate, Yemen. Fifty P. falciparum isolates were collected during a cross-sectional study in Mawza district, Taiz, in the period from October 2013 to April 2014. The isolates were investigated for drug resistance-associated molecular markers in five genes, including P. falciparum CQ resistance transporter (pfcrt) 76T and P. falciparum multidrug resistance 1 (pfmdr1) 86Y as markers of resistance to CQ, mutations in the Kelch 13 (K13) propeller domain for resistance to AS, and P. falciparum dihydrofolate reductase (pfdhfr) and P. falciparum dihydropteroate synthase (pfdhps) genes for resistance to SP. Nested polymerase chain reaction was used to amplify target genes in DNA extracts of the isolates followed by restriction fragment length polymorphism for detecting 76T and 86Y mutations in pfcrt and pfmdr1, respectively, and by DNA sequencing for detecting mutations in K13, pfdhfr and pfdhps. All the investigated isolates from Mawza district were harboring the pfcrt 76T mutant and the pfmdr1 N86 wild-type alleles. The pfdhfr 51I/108N double mutant allele was found in 2.2% (1/45) of the isolates; however, no mutations were detected at codons 436, 437, 540, 581 and 613 of pfdhps. All P. falciparum isolates that were successfully sequenced (n=47) showed the K13 Y493, R539, I543 and C580 wild-type alleles. In conclusion, the pfcrt 76T mutant allele is fixed in the study area about six years after the official withdrawal of CQ, possibly indicating its over-the-counter availability and continued use as a

  20. Determination of the Cytostatic and Cytocidal Activities of Antimalarial Compounds and their Combination Interactions

    PubMed Central

    Sherlach, Katy S.; Roepe, Paul D.

    2014-01-01

    Determining the antiplasmodial activity of candidate antimalarial drugs in vitro identifies new therapies for drug-resistant malaria. Importantly though, activity can be either growth-inhibitory (cytostatic) or parasite-kill (cytocidal), or both. The simple methods described here can allow for distinction between these, as well as definition of drug interactions between two or more compounds. The latter is important in the definition of novel drug combination therapy for malaria. These methods involve live malarial parasite red blood cell culture, routine pharmacology, high-throughput detection of parasite DNA with fluorescent reporters, and routine mathematical analysis of dose – response curves. The techniques and approaches are accessible to most laboratories and require minimal special equipment beyond a fluorescent plate reader and tissue culture facilities. PMID:25445179

  1. Response of falciparum malaria to different antimalarials in Myanmar.

    PubMed Central

    Ejov, M. N.; Tun, T.; Aung, S.; Sein, K.

    1999-01-01

    The purpose of the study was to ascertain the therapeutic efficacy of different treatments for uncomplicated falciparum malaria in the hospitals in Sagaing, northern and eastern Shan, to facilitate updating the existing national antimalarial drug policy. The proposed 14-day trial for monitoring the efficacy of treatments of uncomplicated falciparum malaria is an efficient method for identifying treatment failure patterns at the intermediate level (township hospital) in the Union of Myanmar. Minimal clinical and parasitological data for days 0-14 were required to classify treatment failure and success. Clinical and parasitiological responses on day 3 and days 4-14 were used as clear examples of early and late treatment failure, respectively. Mefloquine is five times more likely to be effective than chloroquine and sulfadoxine pyrimethamine (S-P), whereas chloroquine and S-P treatments have nearly identical failure patterns. The alarming frequency of clinical and parasitological failure (failure rate > 50%) following chloroquine treatment was reported in Sagaing and following S-P treatment in Sagaing and eastern Shan. PMID:10212515

  2. Targeting histone deacetylase inhibitors for anti-malarial therapy.

    PubMed

    Andrews, Katherine T; Tran, Thanh N; Wheatley, Nicole C; Fairlie, David P

    2009-01-01

    It is now clear that histone acetylation plays key roles in regulating gene transcription in both eukaryotes and prokaryotes, the acetylated form inducing gene expression while deacetylation silences genes. Recent studies have identified roles for histone acetyltransferases (HATs) and/or histone deacetylases (HDACs) in a number of parasites including Entamoeba histolytica, Toxoplasma gondii, Schistosoma mansoni, Cryptosporidium sp., Leishmania donovani, Neospora caninum, and Plasmodium falciparum. Here we survey fairly limited efforts to date in profiling antimalarial activities of HDAC inhibitors, showing that such compounds are potent inhibitors of the growth of P. falciparum in vitro and in vivo. Most of the compounds evaluated so far have borne a zinc-binding hydroxamate group that tends to be metabolized in vivo, and thus new zinc-binding groups need to be incorporated into second generation inhibitors in order to mask the catalytic zinc in the active site of HDACs. Also the development of compounds that are selective for parasitic HDACs over mammalian HDACs is still in relative infancy and it will take some time to derive antiparasitic HDAC inhibitor compounds with minimal toxicity for the host and acceptable pharmacokinetic and pharmacodynamic profiles for human treatment. Nevertheless, results to date suggest that HDAC inhibitor development represents a promising new approach to the potential treatment of parasitic infections, including those induced by malaria protozoa, and may offer new therapeutic targets within increasingly drug-resistant malarial parasites. PMID:19355992

  3. Antimalarial potency of the methanol leaf extract of Maerua crassifolia Forssk (Capparaceae)

    PubMed Central

    Christian, Akuodor Godwin; Akanimo, Essiet Grace; Ahunna, Ajoku Gloria; Nwakaego, Ezeunala Mercy; Chimsorom, Chilaka Kingsley

    2014-01-01

    Objective To investigate the in vivo antiplasmodial effect of methanol leaf extract of Maerua crassifolia in mice infected with chloroquine sensitive Plasmodium berghei berghei. Methods The extract was evaluated for activity against early infection, curative effect against established infection at dose levels of 100, 200 and 400 mg/kg p.o. Chloroquine at 10 mg/kg was used as standard drug. Results A dose dependent chemo-suppression of the parasites was obtained at different dose levels of the extract tested with a considerable mean survival time. Conclusions The results support continued investigation of components of traditional medicines as potential new antimalarial agents.

  4. Recycling antimalarial leads for cancer: Antiproliferative properties of N-cinnamoyl chloroquine analogues.

    PubMed

    Pérez, Bianca C; Fernandes, Iva; Mateus, Nuno; Teixeira, Cátia; Gomes, Paula

    2013-12-15

    Cinnamic acids and quinolines are known as useful scaffolds in the discovery of antitumor agents. Therefore, N-cinnamoylated analogues of chloroquine, recently reported as potent dual-action antimalarials, were evaluated against three different cancer cell lines: MKN-28, Caco-2, and MCF-7. All compounds display anti-proliferative activity in the micromolar range against the three cell lines tested, and most of them were more active than their parent drug, chloroquine, against all cell lines tested. Hence, N-cinnamoyl-chloroquine analogues are a good start towards development of affordable antitumor leads. PMID:24184076

  5. Synthesis and Potent Antimalarial Activity of Kalihinol B

    PubMed Central

    2016-01-01

    Of the 50+ kalihinane diterpenoids reported to date, only five had been tested for antimalarial activity, in spite of the fact that kalihinol A is the most potent among the members of the larger family of antimalarial isocyanoterpenes. We have validated a strategy designed to access many of the kalihinanes with a 12-step enantioselective synthesis of kalihinol B, the tetrahydrofuran isomer of kalihinol A (a tetrahydropyran). Kalihinol B shows similarly high potency against chloroquine-resistant Plasmodium falciparum. PMID:25815413

  6. Quality Assurance for Alcohol, Drug Abuse, and Mental Health Services: An Annotated Bibliography.

    ERIC Educational Resources Information Center

    Towery, O. B.; And Others

    This is a comprehensive bibliography for all those in the alcohol, drug abuse and mental health fields who are developing and implementing programs for assuring quality in the services they provide. A major problem is the newness of the language and the unfamilarity with procedures required by the government and others seeking accountability from…

  7. Quality of drug prescribing in older patients: is there a problem and can we improve it?

    PubMed

    Scott, I; Jayathissa, S

    2010-01-01

    Older patients are at high risk of suboptimal prescribing (overuse, underuse and misuse of drugs), which can lead to serious adverse drug reactions (ADR). About one in four patients admitted to hospital are prescribed at least one inappropriate medication and up to 20% of all inpatient deaths are attributed to potentially preventable ADR. Lists of drugs to avoid (unnecessary or where risks outweigh benefits) and drugs not to be omitted (strong indications if there are no contraindications) can assist in identifying suboptimal prescribing although, to date, no trials have established the ability of such screening, by itself, to improve prescribing quality. Remedial strategies proven to be effective in randomized trials include detailed appraisal of medication lists by multidisciplinary teams, which involve geriatricians and close liaison with specialist clinical pharmacists. A multifaceted quality improvement strategy is proposed that includes an aspirational target of no more than five different drugs be regularly prescribed to vulnerable older patients. Achieving this target involves prioritizing drug selection on the basis of strength of indication which may run counter to current disease-specific clinical guideline recommendations based on trials that have excluded most older patients. Such a strategy is worthy of further evaluation in a multicentre randomized trial. PMID:19712203

  8. Achieving sustainability, quality and access: lessons from the world's largest revolving drug fund in Khartoum.

    PubMed

    Witter, S

    2007-01-01

    Ensuring a reliable and affordable supply of essential drugs to health facilities is one of the main challenges facing developing countries. This paper describes the revolving drug fund in Khartoum, which was set up in 1989 to improve access to high quality drugs across the State. An evaluation in 2004 showed that the fund has successfully managed a number of threats to its financial sustainability and has expanded its network of facilities, its range of products and its financial assets. It now supplies essential drugs to 3 million out of the 5 million population of Khartoum each year, at prices between 40% and 100% less than alternative sources. However, results illustrated the tension between achieving an efficient cost-recovery system and access for the poorest.

  9. Quality of Animal Experiments in Anti-Angiogenic Cancer Drug Development – A Systematic Review

    PubMed Central

    Martić-Kehl, Marianne Isabelle; Wernery, Jannis; Folkers, Gerd; Schubiger, Pius August

    2015-01-01

    Translation from preclinical animal research to clinical bedside has proven to be difficult to impossible in many fields of research (e.g. acute stroke, ALS and HIV vaccination development) with oncology showing particularly low translation rates (5% vs. 20% for cardiovascular diseases). Several investigations on published preclinical animal research have revealed that apart from plain species differences, translational problems can arise from low study quality (e.g. study design) or non-representative experimental conditions (e.g. treatment schedule). This review assessed the published experimental circumstances and quality of anti-angiogenic cancer drug development in 232 in vivo studies. The quality of study design was often insufficient; at least the information published about the experiments was not satisfactory in most cases. There was no quality improvement over time, with the exception of conflict of interest statements. This increase presumably arose mainly because journal guidelines request such statements more often recently. Visual inspection of data and a cluster analysis confirmed a trend described in literature that low study quality tends to overestimate study outcome. It was also found that experimental outcome was more favorable when a potential drug was investigated as the main focus of a study, compared to drugs that were used as comparison interventions. We assume that this effect arises from the frequent neglect of blinding investigators towards treatment arms and refer to it as hypothesis bias. In conclusion, the reporting and presumably also the experimental performance of animal studies in drug development for oncology suffer from similar shortcomings as other fields of research (such as stroke or ALS). We consider it necessary to enforce experimental quality and reporting that corresponds to the level of clinical studies. It seems that only clear journal guidelines or guidelines from licensing authorities, where failure to fulfill

  10. Assessment of Methodological Quality of Economic Evaluations in Belgian Drug Reimbursement Applications

    PubMed Central

    Simoens, Steven

    2013-01-01

    Objectives This paper aims to assess the methodological quality of economic evaluations included in Belgian reimbursement applications for Class 1 drugs. Materials and Methods For 19 reimbursement applications submitted during 2011 and Spring 2012, a descriptive analysis assessed the methodological quality of the economic evaluation, evaluated the assessment of that economic evaluation by the Drug Reimbursement Committee and the response to that assessment by the company. Compliance with methodological guidelines issued by the Belgian Healthcare Knowledge Centre was assessed using a detailed checklist of 23 methodological items. The rate of compliance was calculated based on the number of economic evaluations for which the item was applicable. Results Economic evaluations tended to comply with guidelines regarding perspective, target population, subgroup analyses, comparator, use of comparative clinical data and final outcome measures, calculation of costs, incremental analysis, discounting and time horizon. However, more attention needs to be paid to the description of limitations of indirect comparisons, the choice of an appropriate analytic technique, the expression of unit costs in values for the current year, the estimation and valuation of outcomes, the presentation of results of sensitivity analyses, and testing the face validity of model inputs and outputs. Also, a large variation was observed in the scope and depth of the quality assessment by the Drug Reimbursement Committee. Conclusions Although general guidelines exist, pharmaceutical companies and the Drug Reimbursement Committee would benefit from the existence of a more detailed checklist of methodological items that need to be reported in an economic evaluation. PMID:24386474

  11. A Repeat Random Survey of the Prevalence of Falsified and Substandard Antimalarials in the Lao PDR: A Change for the Better.

    PubMed

    Tabernero, Patricia; Mayxay, Mayfong; Culzoni, María Julia; Dwivedi, Prabha; Swamidoss, Isabel; Allan, Elizabeth Louise; Khanthavong, Maniphone; Phonlavong, Chindaphone; Vilayhong, Chantala; Yeuchaixiong, Sengchanh; Sichanh, Chanvilay; Sengaloundeth, Sivong; Kaur, Harparkash; Fernández, Facundo M; Green, Michael D; Newton, Paul N

    2015-06-01

    In 2003, a stratified random sample survey was conducted in the Lao People's Democratic Republic (Laos) to study the availability and quality of antimalarials in the private sector. In 2012, this survey was repeated to allow a statistically valid analysis of change through time. The counterfeit detection device 3 (CD-3) was used to assess packaging quality in the field and HPLC and mass spectroscopy analysis chemical analysis performed. The availability of oral artesunate monotherapies had significantly decreased from 22.9% (22) of 96 outlets in southern Laos in 2003 to 4.8% (7) of 144 outlets in 2012 (P < 0.0001). All the samples collected in the 2012 survey contained the correct active pharmaceutical ingredients (APIs) in contrast to the 21 (84%) falsified artesunate samples found in the 2003 survey. Although none of the medicines found in 2012 survey had evidence for falsification, 25.4% (37) of the samples were outside the 90-110% pharmacopeial limits of the label claim, suggesting that they were substandard or degraded. Results obtained from this survey show that patients are still exposed to poorly manufactured drugs or to ineffective medicines such as chloroquine. The quality of artemisinin-based combination therapies (ACTs) used in Laos needs to be monitored, since falsified ACTs would have devastating consequences in public health. PMID:25897062

  12. A Repeat Random Survey of the Prevalence of Falsified and Substandard Antimalarials in the Lao PDR: A Change for the Better

    PubMed Central

    Tabernero, Patricia; Mayxay, Mayfong; Culzoni, María Julia; Dwivedi, Prabha; Swamidoss, Isabel; Allan, Elizabeth Louise; Khanthavong, Maniphone; Phonlavong, Chindaphone; Vilayhong, Chantala; Yeuchaixiong, Sengchanh; Sichanh, Chanvilay; Sengaloundeth, Sivong; Kaur, Harparkash; Fernández, Facundo M.; Green, Michael D.; Newton, Paul N.

    2015-01-01

    In 2003, a stratified random sample survey was conducted in the Lao People's Democratic Republic (Laos) to study the availability and quality of antimalarials in the private sector. In 2012, this survey was repeated to allow a statistically valid analysis of change through time. The counterfeit detection device 3 (CD-3) was used to assess packaging quality in the field and HPLC and mass spectroscopy analysis chemical analysis performed. The availability of oral artesunate monotherapies had significantly decreased from 22.9% (22) of 96 outlets in southern Laos in 2003 to 4.8% (7) of 144 outlets in 2012 (P < 0.0001). All the samples collected in the 2012 survey contained the correct active pharmaceutical ingredients (APIs) in contrast to the 21 (84%) falsified artesunate samples found in the 2003 survey. Although none of the medicines found in 2012 survey had evidence for falsification, 25.4% (37) of the samples were outside the 90–110% pharmacopeial limits of the label claim, suggesting that they were substandard or degraded. Results obtained from this survey show that patients are still exposed to poorly manufactured drugs or to ineffective medicines such as chloroquine. The quality of artemisinin-based combination therapies (ACTs) used in Laos needs to be monitored, since falsified ACTs would have devastating consequences in public health. PMID:25897062

  13. Role of quassinoids as potential antimalarial agents: An in silico approach

    PubMed Central

    Rampogu, Shailima

    2015-01-01

    Background: Malaria is an infection caused by mosquitoes in human beings which can be dangerous if untreated. A well known plant product, quassinoids are known to have antimalarial activity. These bioactive phytochemicals belong to the triterpene family. Quassinoids are used in the present study to act against malarial dihydrofolate reductase (Pf-DHFR), a potential antimalarial target. Nevertheless, viṣama jvara (~malaria) has been treated with the bark of Cinchona since a long time. Aim: The aim of the present experiment is to perform the protein-ligand docking for Pf- DHFR and Quassinoids and study their binding affinities. Setting and Design: The software used for the present study is the discovery studio (Accelrys 2.1), Protein Data Bank (PDB), and Chemsketch. Materials and Methods: The protein for the present study was imported from protein data bank with the PDB Id, 4dpd and was prepared for docking. The ligands used for the study are the quassinoids. They were drawn using chemsketch and the 3D structures were generated. The docking was done subsequently. Statistical Analysis Used: Molecular modeling technique was used for the protein-ligand docking analysis. Results: The docking results showed that the Quassinoids Model_1 showed the highest dock score of 40.728. Conclusion: The present study proves the promising potential of quassinoids as novel drugs against malaria. The dock results conclude that the quassinoids can be adopted as an alternative drug against malaria. PMID:26865740

  14. Evaluation of French Guiana traditional antimalarial remedies.

    PubMed

    Bertani, S; Bourdy, G; Landau, I; Robinson, J C; Esterre, Ph; Deharo, E

    2005-04-01

    In order to evaluate the antimalarial potential of traditional remedies used in French Guiana, 35 remedies were prepared in their traditional form and screened for blood schizonticidal activity in vitro on Plasmodium falciparum chloroquine re4sistant strain (W2). Some of these extracts were screened in vivo against Plasmodium yoelii rodent malaria. Ferriprotoporphyrin inhibition test was also performed. Four remedies, widely used among the population as preventives, were able to inhibit more than 50% of the parasite growth in vivo at around 100 mg/kg: Irlbachia alata (Gentiananceae), Picrolemma pseudocoffea (Simaroubaceae), Quassia amara (Simaroubaceae), Tinospora crispa (Menispermaceae) and Zanthoxylum rhoifolium (Rutaceae). Five remedies displayed an IC50 in vitro < 10 microg/ml: Picrolemma pseudocoffea, Pseudoxandra cuspidata (Annonaceae) and Quassia amara leaves and stem, together with a multi-ingredient recipe. Two remedies were more active than a Cinchona preparation on the ferriprotoporphyrin inhibition test: Picrolemma pseudocoffea and Quassia amara. We also showed that a traditional preventive remedy, made from Geissospermum argenteum bark macerated in rum, was able to impair the intrahepatic cycle of the parasite. For the first time, traditional remedies from French Guiana have been directly tested on malarial pharmacological assays and some have been shown to be active.

  15. Benefits of Exercise for the Quality of Life of Drug-Dependent Patients.

    PubMed

    Giménez-Meseguer, Jorge; Tortosa-Martínez, Juan; de los Remedios Fernández-Valenciano, María

    2015-01-01

    This study combined quantitative and qualitative research methods to evaluate quality-of-life changes in drug-dependent patients after participation in a group-based exercise program. Quality of life (SF-36) and physical fitness (six-minute Walk Test, Timed Get Up and Go Test, and Chair Stand Test) were quantitatively determined in a group (n=37) of drug-dependent patients before and after a 12-week group exercise program (n=18) or routine care (n=19). Additionally, in-depth interviews were conducted at the end of the program with a subsample of 11 participants from the exercise group. Quantitative results showed improvements in fitness and different aspects of quality of life, such as physical function, mental health, vitality, social function, and general health perception. Qualitative results showed specific physical benefits (decreased injuries and muscle pain, decreased weight, and increased vitality with improvement in activities of daily living), psychological benefits (forgetting about everyday problems, improved mood, decreased stress and anxiety), social benefits, and a reduction in craving. The results of this study provide insight into the importance of exercise for the quality of life and recovery process of drug-dependent patients.

  16. Benefits of Exercise for the Quality of Life of Drug-Dependent Patients.

    PubMed

    Giménez-Meseguer, Jorge; Tortosa-Martínez, Juan; de los Remedios Fernández-Valenciano, María

    2015-01-01

    This study combined quantitative and qualitative research methods to evaluate quality-of-life changes in drug-dependent patients after participation in a group-based exercise program. Quality of life (SF-36) and physical fitness (six-minute Walk Test, Timed Get Up and Go Test, and Chair Stand Test) were quantitatively determined in a group (n=37) of drug-dependent patients before and after a 12-week group exercise program (n=18) or routine care (n=19). Additionally, in-depth interviews were conducted at the end of the program with a subsample of 11 participants from the exercise group. Quantitative results showed improvements in fitness and different aspects of quality of life, such as physical function, mental health, vitality, social function, and general health perception. Qualitative results showed specific physical benefits (decreased injuries and muscle pain, decreased weight, and increased vitality with improvement in activities of daily living), psychological benefits (forgetting about everyday problems, improved mood, decreased stress and anxiety), social benefits, and a reduction in craving. The results of this study provide insight into the importance of exercise for the quality of life and recovery process of drug-dependent patients. PMID:26595433

  17. Increasing Access to Subsidized Artemisinin-based Combination Therapy through Accredited Drug Dispensing Outlets in Tanzania

    PubMed Central

    2011-01-01

    Morogoro Rural. Conclusions The intervention increased access to affordable ACTs for underserved populations. Indications are that antimalarial monotherapies are being "crowded out" of the market. Importantly, the transition to ACTs has been accomplished in an environment where the safety and efficacy of the drugs and the quality of services are being monitored and regulated. This paper presents a description of the pilot program implementation, results of the program evaluation, and a discussion of the challenges and recommendations that will be used to guide rollout of subsidized ACT in ADDOs in the rest of Tanzania and possibly in other countries. PMID:21658259

  18. Fixed drug eruption in Nigeria.

    PubMed

    Nnoruka, Edith N; Ikeh, V O; Mbah, A U

    2006-09-01

    Fixed drug eruption (FDE) causes cosmetic embarrassment in Nigerian patients, particularly when the characteristic hyperpigmented patches affect the face and lips. Drugs that have been implicated in the etiology of FDE, and the sites of lesions, may vary from country to country. Antimalarials, such as Fansidar, Fancimef, Maloxine, Amalar, and Metakelfin, were the most common offending agents, accounting for 38% of FDEs, followed by trimethoprim + sulfamethoxazole (co-trimoxazole) (28%), dipyrones (10%), Butazolidin (6%), thiacetazone (6%), metronidazole (4%), paracetamol (3%), and naproxen (3%). Lesions induced by the combination of sulfadoxine and pyrimethamine (in antimalarials) mainly involved the face and lips. In most cases, patients took these sulfa-containing antimalarials in combination with numerous other drugs, particularly analgesics. Unlike chloroquine-induced pruritus, which affects most Africans, the association between antimalarials and FDE has not been well documented in our region. Co-trimoxazole was associated more often than antimalarials with FDEs involving the mucocutaneous junctions of the genitalia and lips. Males with genital lesions on the glans penis represented 11 (48%) of those with co-trimoxazole hypersensitivity. The trunk and limbs were affected mainly by pyrazoles and Butazolidin, respectively; however, solitary lesions on the trunk were usually due to co-trimoxazole, whereas solitary lesions on the limbs were associated with Butazolidin.

  19. Poor quality drugs: grand challenges in high throughput detection, countrywide sampling, and forensics in developing countries†

    PubMed Central

    Fernandez, Facundo M.; Hostetler, Dana; Powell, Kristen; Kaur, Harparkash; Green, Michael D.; Mildenhall, Dallas C.; Newton, Paul N.

    2012-01-01

    Throughout history, poor quality medicines have been a persistent problem, with periodical crises in the supply of antimicrobials, such as fake cinchona bark in the 1600s and fake quinine in the 1800s. Regrettably, this problem seems to have grown in the last decade, especially afflicting unsuspecting patients and those seeking medicines via on-line pharmacies. Here we discuss some of the challenges related to the fight against poor quality drugs, and counterfeits in particular, with an emphasis on the analytical tools available, their relative performance, and the necessary workflows needed for distinguishing between genuine, substandard, degraded and counterfeit medicines. PMID:21107455

  20. A Delphi Process to Optimize Quality and Performance of Drug Evaluation in Neonates

    PubMed Central

    Legrand, Frederic; Boulkedid, Rym; Elie, Valery; Leroux, Stephanie; Valls, Elizabeth; Van den Anker, Johannes N.; Jacqz-Aigrain, Evelyne

    2014-01-01

    Background Neonatal trials remain difficult to conduct for several reasons: in particular the need for study sites to have an existing infrastructure in place, with trained investigators and validated quality procedures to ensure good clinical, laboratory practices and a respect for high ethical standards. The objective of this work was to identify the major criteria considered necessary for selecting neonatal intensive care units that are able to perform drug evaluations competently. Methodology and Main Findings This Delphi process was conducted with an international multidisciplinary panel of 25 experts from 13 countries, selected to be part of two committees (a scientific committee and an expert committee), in order to validate criteria required to perform drug evaluation in neonates. Eighty six items were initially selected and classified under 7 headings: “NICUs description - Level of care” (21), “Ability to perform drug trials: NICU organization and processes (15), “Research Experience” (12), “Scientific competencies and area of expertise” (8), “Quality Management” (16), “Training and educational capacity” (8) and “Public involvement” (6). Sixty-one items were retained and headings were rearranged after the first round, 34 were selected after the second round. A third round was required to validate 13 additional items. The final set includes 47 items divided under 5 headings. Conclusion A set of 47 relevant criteria will help to NICUs that want to implement, conduct or participate in drug trials within a neonatal network identify important issues to be aware of. Summary Points 1) Neonatal trials remain difficult to conduct for several reasons: in particular the need for study sites to have an existing infrastructure in place, with trained investigators and validated quality procedures to ensure good clinical, laboratory practices and a respect for high ethical standards. 2) The present Delphi study was conducted with an

  1. The effect of an anti-malarial subsidy programme on the quality of service provision of artemisinin-based combination therapy in Kenya: a cluster-randomized, controlled trial

    PubMed Central

    2013-01-01

    Background Many patients with suspected malaria in sub-Saharan Africa seek treatment from private providers, but this sector suffers from sub-standard medicine dispensing practices. To improve the quality of care received for presumptive malaria from the highly accessed private retail sector in western Kenya, subsidized pre-packaged artemether-lumefantrine (AL) was provided to private retailers, together with a one day training for retail staff on malaria diagnosis and treatment, job aids and community engagement activities. Methods The intervention was assessed using a cluster-randomized, controlled design. Provider and mystery-shopper cross-sectional surveys were conducted at baseline and eight months post-intervention to assess provider practices. Data were analysed based on cluster-level summaries, comparing control and intervention arms. Results On average, 564 retail outlets were interviewed per year. At follow-up, 43% of respondents reported that at least one staff member had attended the training in the intervention arm. The intervention significantly increased the percentage of providers knowing the first line treatment for uncomplicated malaria by 24.2% points (confidence interval (CI): 14.8%, 33.6%; adjusted p=0.0001); the percentage of outlets stocking AL by 31.7% points (CI: 22.0%, 41.3%; adjusted p=0.0001); and the percentage of providers prescribing AL for presumptive malaria by 23.6% points (CI: 18.7%, 28.6%; adjusted p=0.0001). Generally outlets that received training and job aids performed better than those receiving one or none of these intervention components. Conclusion Overall, subsidizing ACT and retailer training can significantly increase the percentage of outlets stocking and selling AL for the presumptive treatment of malaria, but further research is needed on strategies to improve the provision of counselling advice to retail customers. PMID:23452547

  2. Structure-activity relationship studies of pyrrolone antimalarial agents.

    PubMed

    Murugesan, Dinakaran; Kaiser, Marcel; White, Karen L; Norval, Suzanne; Riley, Jennifer; Wyatt, Paul G; Charman, Susan A; Read, Kevin D; Yeates, Clive; Gilbert, Ian H

    2013-09-01

    Previously reported pyrrolones, such as TDR32570, exhibited potential as antimalarial agents; however, while these compounds have potent antimalarial activity, they suffer from poor aqueous solubility and metabolic instability. Here, further structure-activity relationship studies are described that aimed to solve the developability issues associated with this series of compounds. In particular, further modifications to the lead pyrrolone, involving replacement of a phenyl ring with a piperidine and removal of a potentially metabolically labile ester by a scaffold hop, gave rise to derivatives with improved in vitro antimalarial activities against Plasmodium falciparum K1, a chloroquine- and pyrimethamine-resistant parasite strain, with some derivatives exhibiting good selectivity for parasite over mammalian (L6) cells. Three representative compounds were selected for evaluation in a rodent model of malaria infection, and the best compound showed improved ability to decrease parasitaemia and a slight increase in survival.

  3. Design, synthesis and antimalarial evaluation of novel thiazole derivatives.

    PubMed

    Bueno, José María; Carda, Miguel; Crespo, Benigno; Cuñat, Ana Carmen; de Cozar, Cristina; León, María Luisa; Marco, J Alberto; Roda, Nuria; Sanz-Cervera, Juan F

    2016-08-15

    As part of our medicinal chemistry program's ongoing search for compounds with antimalarial activity, we prepared a series of thiazole analogs and conducted a SAR study analyzing their in vitro activities against the chloroquine-sensitive Plasmodium falciparum 3D7 strain. The results indicate that modifications of the N-aryl amide group linked to the thiazole ring are the most significant in terms of in vitro antimalarial activity, leading to compounds with high antimalarial potency and low cytotoxicity in HepG2 cell lines. Furthermore, the observed SAR implies that non-bulky, electron-withdrawing groups are preferred at ortho position on the phenyl ring, whereas small atoms such as H or F are preferred at para position. Finally, replacement of the phenyl ring by a pyridine affords a compound with similar potency, but with potentially better physicochemical properties which could constitute a new line of research for further studies. PMID:27432764

  4. Parasites resistant to the antimalarial atovaquone fail to transmit by mosquitoes.

    PubMed

    Goodman, Christopher D; Siregar, Josephine E; Mollard, Vanessa; Vega-Rodríguez, Joel; Syafruddin, Din; Matsuoka, Hiroyuki; Matsuzaki, Motomichi; Toyama, Tomoko; Sturm, Angelika; Cozijnsen, Anton; Jacobs-Lorena, Marcelo; Kita, Kiyoshi; Marzuki, Sangkot; McFadden, Geoffrey I

    2016-04-15

    Drug resistance compromises control of malaria. Here, we show that resistance to a commonly used antimalarial medication, atovaquone, is apparently unable to spread. Atovaquone pressure selects parasites with mutations in cytochrome b, a respiratory protein with low but essential activity in the mammalian blood phase of the parasite life cycle. Resistance mutations rescue parasites from the drug but later prove lethal in the mosquito phase, where parasites require full respiration. Unable to respire efficiently, resistant parasites fail to complete mosquito development, arresting their life cycle. Because cytochrome b is encoded by the maternally inherited parasite mitochondrion, even outcrossing with wild-type strains cannot facilitate spread of resistance. Lack of transmission suggests that resistance will be unable to spread in the field, greatly enhancing the utility of atovaquone in malaria control. PMID:27081071

  5. Nurses' perception of the quality of care they provide to hospitalized drug addicts: testing the theory of reasoned action.

    PubMed

    Natan, Merav Ben; Beyil, Valery; Neta, Okev

    2009-12-01

    A correlational design was used to examine nursing staff attitudes and subjective norms manifested in intended and actual care of drug users based on the Theory of Reasoned Action. One hundred and thirty-five nursing staff from three central Israeli hospitals completed a questionnaire examining theory-based variables as well as sociodemographic and professional characteristics. Most respondents reported a high to very high level of actual or intended care of drug users. Nurses' stronger intentions to provide quality care to drug users were associated with more positive attitudes. Nursing staff members had moderately negative attitudes towards drug users. Nurses were found to hold negative stereotypes of drug addict patients and most considered the management of this group difficult. Positive attitudes towards drug users, perceived expectations of others and perceived correctness of the behaviour are important in their effect on the intention of nurses to provide high-quality care to hospitalized patients addicted to drugs.

  6. A Divergent SAR Study Allows Optimization of a Potent 5-HT2c Inhibitor to a Promising Antimalarial Scaffold

    PubMed Central

    2012-01-01

    From the 13 533 chemical structures published by GlaxoSmithKline in 2010, we identified 47 quality starting points for lead optimization. One of the most promising hits was the TCMDC-139046, a molecule presenting an indoline core, which is well-known for its anxiolytic properties by interacting with serotonin antagonist receptors 5-HT2. The inhibition of this target will complicate the clinical development of these compounds as antimalarials. Herein, we present the antimalarial profile of this series and our efforts to avoid interaction with this receptor, while maintaining a good antiparasitic potency. By using a double-divergent structure–activity relationship analysis, we have obtained a novel lead compound harboring an indoline core. PMID:24900481

  7. Modeling structure-activity relationships of prodiginines with antimalarial activity using GA/MLR and OPS/PLS.

    PubMed

    de Campos, Luana Janaína; de Melo, Eduardo Borges

    2014-11-01

    In the present study, we performed a multivariate quantitative structure-activity relationship (QSAR) analysis of 52 prodiginines with antimalarial activity. Variable selection was based on the genetic algorithm (GA) and ordered predictor selection (OPS) approaches, and the models were built using the multiple linear regression (MLR) and partial least squares (PLS) regression methods. The leave-N-out crossvalidation and y-randomization tests showed that the models were robust and free from chance correlation. The mechanistic interpretation of the results was supported by earlier findings. In addition, the comparison of our models with those previously described indicated that the OPS/PLS-based model had a higher quality of external prediction. Thus, this study provides a comprehensive approach to the evaluation of the antimalarial activity of prodiginines, which may be used as a support tool in designing new therapeutic agents for malaria.

  8. Discovery and optimisation studies of antimalarial phenotypic hits.

    PubMed

    Mital, Alka; Murugesan, Dinakaran; Kaiser, Marcel; Yeates, Clive; Gilbert, Ian H

    2015-10-20

    There is an urgent need for the development of new antimalarial compounds. As a result of a phenotypic screen, several compounds with potent activity against the parasite Plasmodium falciparum were identified. Characterization of these compounds is discussed, along with approaches to optimise the physicochemical properties. The in vitro antimalarial activity of these compounds against P. falciparum K1 had EC50 values in the range of 0.09-29 μM, and generally good selectivity (typically >100-fold) compared to a mammalian cell line (L6). One example showed no significant activity against a rodent model of malaria, and more work is needed to optimise these compounds. PMID:26408453

  9. Anti-malarial market and policy surveys in sub-Saharan Africa.

    PubMed

    Diap, Graciela; Amuasi, John; Boakye, Isaac; Sevcsik, Ann-Marie; Pecoul, Bernard

    2010-01-01

    At a recent meeting (Sept 18, 2009) in which reasons for the limited access to artemisinin-based combination therapy (ACT) in sub-Saharan Africa were discussed, policy and market surveys on anti-malarial drug availability and accessibility in Burundi and Sierra Leone were presented in a highly interactive brainstorming session among key stakeholders across private, public, and not-for-profit sectors. The surveys, the conduct of which directly involved the national malaria control programme managers of the two countries, provides the groundwork for evidence-based policy implementation. The results of the surveys could be extrapolated to other countries with similar socio-demographic and malaria profiles. The meeting resulted in recommendations on key actions to be taken at the global, national, and community level for better ACT accessibility. At the global level, both public and private sectors have actions to take to strengthen policies that lead to the replacement of loose blister packs with fixed-dose ACT products, develop strategies to ban inappropriate anti-malarials and regulate those bans, and facilitate technology and knowledge transfer to scale up production of fixed-dose ACT products, which should be readily available and affordable to those patients who are in the greatest need of these medicines. At the national level, policies that regulate the anti-malarial medicines market should be enacted and enforced. The public sector, including funding donors, should participate in ensuring that the private sector is engaged in the ACT implementation process. Research similar to the surveys discussed is important for other countries to develop and evaluate the right incentives at a local level. At the community level, community outreach and education about appropriate preventive and treatment measures must continue and be strengthened, with service delivery systems developed within both public and private sectors, among other measures, to decrease access to

  10. Anti-malarial market and policy surveys in sub-Saharan Africa.

    PubMed

    Diap, Graciela; Amuasi, John; Boakye, Isaac; Sevcsik, Ann-Marie; Pecoul, Bernard

    2010-01-01

    At a recent meeting (Sept 18, 2009) in which reasons for the limited access to artemisinin-based combination therapy (ACT) in sub-Saharan Africa were discussed, policy and market surveys on anti-malarial drug availability and accessibility in Burundi and Sierra Leone were presented in a highly interactive brainstorming session among key stakeholders across private, public, and not-for-profit sectors. The surveys, the conduct of which directly involved the national malaria control programme managers of the two countries, provides the groundwork for evidence-based policy implementation. The results of the surveys could be extrapolated to other countries with similar socio-demographic and malaria profiles. The meeting resulted in recommendations on key actions to be taken at the global, national, and community level for better ACT accessibility. At the global level, both public and private sectors have actions to take to strengthen policies that lead to the replacement of loose blister packs with fixed-dose ACT products, develop strategies to ban inappropriate anti-malarials and regulate those bans, and facilitate technology and knowledge transfer to scale up production of fixed-dose ACT products, which should be readily available and affordable to those patients who are in the greatest need of these medicines. At the national level, policies that regulate the anti-malarial medicines market should be enacted and enforced. The public sector, including funding donors, should participate in ensuring that the private sector is engaged in the ACT implementation process. Research similar to the surveys discussed is important for other countries to develop and evaluate the right incentives at a local level. At the community level, community outreach and education about appropriate preventive and treatment measures must continue and be strengthened, with service delivery systems developed within both public and private sectors, among other measures, to decrease access to

  11. Quality of Reporting of Serious Adverse Drug Events to an Institutional Review Board

    PubMed Central

    Dorr, David A.; Burdon, Rachel; West, Dennis P.; Lagman, Jennifer; Georgopoulos, Christina; Belknap, Steven M.; McKoy, June M.; Djulbegovic, Benjamin; Edwards, Beatrice J.; Weitzman, Sigmund A.; Boyle, Simone; Tallman, Martin S.; Talpaz, Moshe; Sartor, Oliver; Bennett, Charles L.

    2009-01-01

    Purpose Serious adverse drug event (sADE) reporting to Institutional Review Boards (IRB) is essential to ensure pharmaceutical safety. However, the quality of these reports has not been studied. Safety reports are especially important for cancer drugs that receive accelerated Food and Drug Administration approval, like imatinib, as preapproval experience with these drugs is limited. We evaluated the quality, accuracy, and completeness of sADE reports submitted to an IRB. Experimental Design sADE reports submitted to an IRB from 14 clinical trials with imatinib were reviewed. Structured case report forms, containing detailed clinical data fields and a validated causality assessment instrument, were developed. Two forms were generated for each ADE, the first populated with data abstracted from the IRB reports, and the second populated with data from the corresponding clinical record. Completeness and causality assessments were evaluated for each of the two sources, and then compared. Accuracy (concordance between sources) was also assessed. Results Of 115 sADEs reported for 177 cancer patients to the IRB, overall completeness of adverse event descriptions was 2.4-fold greater for structured case report forms populated with information from the clinical record versus the corresponding forms from IRB reports (95.0% versus 40.3%, P < 0.05). Information supporting causality assessments was recorded 3.5-fold more often in primary data sources versus IRB adverse event descriptions (93% versus 26%, P < 0.05). Some key clinical information was discrepant between the two sources. Conclusions The use of structured syndrome-specific case report forms could enhance the quality of reporting to IRBs, thereby improving the safety of pharmaceuticals administered to cancer patients. PMID:19458059

  12. Formulation and particle size reduction improve bioavailability of poorly water-soluble compounds with antimalarial activity.

    PubMed

    Wang, Hongxing; Li, Qigui; Reyes, Sean; Zhang, Jing; Xie, Lisa; Melendez, Victor; Hickman, Mark; Kozar, Michael P

    2013-01-01

    Decoquinate (DQ) is highly effective at killing malaria parasites in vitro; however, it is extremely insoluble in water. In this study, solid dispersion method was used for DQ formulation which created a suitable physical form of DQ in aqueous phase for particle manipulation. Among many polymers and surfactants tested, polyvinylpyrrolidone 10, a polymer, and L- α -phosphatidylcholine or polysorbate, two surfactants, were chosen as DQ formulation components. The formulation particles were reduced to a mean size between 200 to 400 nm, which was stable in aqueous medium for at least three weeks. Pharmacokinetic (PK) studies showed that compared to DQ microparticle suspension, a nanoparticle formulation orally dosed to mice showed a 14.47-fold increase in area under the curve (AUC) of DQ plasma concentration and a 4.53-fold increase in AUC of DQ liver distribution. WR 299666, a poorly water-soluble compound with antimalarial activity, was also tested and successfully made into nanoparticle formulation without undergoing solid dispersion procedure. We concluded that nanoparticles generated by using appropriate formulation components and sufficient particle size reduction significantly increased the bioavailability of DQ and could potentially turn this antimalarial agent to a therapeutic drug.

  13. An Alternative Paradigm for the Role of Antimalarial Plants in Africa

    PubMed Central

    Maranz, Steven

    2012-01-01

    Most investigations into the antimalarial activity of African plants are centered on finding an indigenous equivalent to artemisinin, the compound from which current frontline antimalarial drugs are synthesized. As a consequence, the standard practice in ethnopharmacological research is to use in vitro assays to identify compounds that inhibit parasites at nanomolar concentrations. This approach fails to take into consideration the high probability of acquisition of resistance to parasiticidal compounds since parasite populations are placed under direct selection for genetic that confers a survival advantage. Bearing in mind Africa's long exposure to malaria and extensive ethnobotanical experimentation with both therapies and diet, it is more likely that compounds not readily overcome by Plasmodium parasites would have been retained in the pharmacopeia and cuisine. Such compounds are characterized by acting primarily on the host rather than directly targeting the parasite and thus cannot be adequately explored in vitro. If Africa's long history with malaria has in fact produced effective plant therapies, their scientific elucidation will require a major emphasis on in vivo investigation. PMID:22593717

  14. Do ethnobotanical and laboratory data predict clinical safety and efficacy of anti-malarial plants?

    PubMed Central

    2011-01-01

    Background Over 1200 plant species are reported in ethnobotanical studies for the treatment of malaria and fevers, so it is important to prioritize plants for further development of anti-malarials. Methods The “RITAM score” was designed to combine information from systematic literature searches of published ethnobotanical studies and laboratory pharmacological studies of efficacy and safety, in order to prioritize plants for further research. It was evaluated by correlating it with the results of clinical trials. Results and discussion The laboratory efficacy score correlated with clinical parasite clearance (rs=0.7). The ethnobotanical component correlated weakly with clinical symptom clearance but not with parasite clearance. The safety component was difficult to validate as all plants entering clinical trials were generally considered safe, so there was no clinical data on toxic plants. Conclusion The RITAM score (especially the efficacy and safety components) can be used as part of the selection process for prioritising plants for further research as anti-malarial drug candidates. The validation in this study was limited by the very small number of available clinical studies, and the heterogeneity of patients included. PMID:21411018

  15. Quality of Online Pharmacies and Websites Selling Prescription Drugs: A Systematic Review

    PubMed Central

    Merla, Anna; Schulz, Peter J; Gelatti, Umberto

    2011-01-01

    Background Online pharmacies are companies that sell pharmaceutical preparations, including prescription-only drugs, on the Internet. Very little is known about this phenomenon because many online pharmacies operate from remote countries, where legal bases and business practices are largely inaccessible to international research. Objective The aim of the study was to perform an up-to-date and comprehensive review of the scientific literature focusing on the broader picture of online pharmacies by scanning several scientific and institutional databases, with no publication time limits. Methods We searched 4 electronic databases up to January 2011 and the gray literature on the Internet using the Google search engine and its tool Google Scholar. We also investigated the official websites of institutional agencies (World Health Organization, and US and European centers for disease control and drug regulation authorities). We focused specifically on online pharmacies offering prescription-only drugs. We decided to analyze and report only articles with original data, in order to review all the available data regarding online pharmacies and their usage. Results We selected 193 relevant articles: 76 articles with original data, and 117 articles without original data (editorials, regulation articles, or the like) including 5 reviews. The articles with original data cover samples of online pharmacies in 47 cases, online drug purchases in 13, consumer characteristics in 15, and case reports on adverse effects of online drugs in 12. The studies show that random samples with no specific limits to prescription requirements found that at least some websites sold drugs without a prescription and that an online questionnaire was a frequent tool to replace prescription. Data about geographical characteristics show that this information can be concealed in many websites. The analysis of drug offer showed that online a consumer can get virtually everything. Regarding quality of drugs

  16. Differences in anti-malarial activity of 4-aminoalcohol quinoline enantiomers and investigation of the presumed underlying mechanism of action

    PubMed Central

    2012-01-01

    Background A better anti-malarial efficiency and lower neurotoxicity have been reported for mefloquine (MQ) (+)- enantiomer. However, the importance of stereoselectivity remains poorly understood as the anti-malarial activity of pure enantiomer MQ analogues has never been described. Building on these observations, a series of enantiopure 4-aminoalcohol quinoline derivatives has previously been synthesized to optimize the efficiency and reduce possible adverse effects. Their in vitro activity on Plasmodium falciparum W2 and 3D7 strains is reported here along with their inhibition of β-haematin formation and peroxidative degradation of haemin, two possible mechanisms of action of anti-malarial drugs. Results The (S)-enantiomers of this series of 4-aminoalcohol quinoline derivatives were found to be at least as effective as both chloroquine (CQ) and MQ. The derivative with a 5-carbon side-chain length was the more efficient on both P. falciparum strains. (R )-enantiomers displayed an activity decreased by 2 to 15-fold as compared to their (S) counterparts. The inhibition of β-haematin formation was significantly stronger with all tested compounds than with MQ, irrespective of the stereochemistry. Similarly, the inhibition of haemin peroxidation was significantly higher for both (S) and (R)-enantiomers of derivatives with a side-chain length of five or six carbons than for MQ and CQ. Conclusions The prominence of stereochemistry in the anti-malarial activity of 4-aminoalcohol quinoline derivatives is confirmed. The inhibition of β-haematin formation and haemin peroxidation can be put forward as presumed mechanisms of action but do not account for the stereoselectivity of action witnessed in vitro. PMID:22401346

  17. Nail changes caused by systemic drugs or ingestants.

    PubMed

    Daniel, C R; Scher, R K

    1985-07-01

    Systemic drugs or ingestants may affect the nails. Changes vary from asymptomatic growth rate changes and pigmentation abnormalities to nail shedding and permanent deformity. The former two changes are most common. Presented are changes in nails caused by antibiotics, cancer chemotherapeutic drugs, poisons and ingestants, antimalarial drugs, and miscellaneous drugs.

  18. In vitro-in vivo Pharmacokinetic correlation model for quality assurance of antiretroviral drugs

    PubMed Central

    Restrepo Valencia, Piedad

    2015-01-01

    Introduction: The in vitro-in vivo pharmacokinetic correlation models (IVIVC) are a fundamental part of the drug discovery and development process. The ability to accurately predict the in vivo pharmacokinetic profile of a drug based on in vitro observations can have several applications during a successful development process. Objective: To develop a comprehensive model to predict the in vivo absorption of antiretroviral drugs based on permeability studies, in vitro and in vivo solubility and demonstrate its correlation with the pharmacokinetic profile in humans. Methods: Analytical tools to test the biopharmaceutical properties of stavudine, lamivudine y zidovudine were developed. The kinetics of dissolution, permeability in caco-2 cells and pharmacokinetics of absorption in rabbits and healthy volunteers were evaluated. Results: The cumulative areas under the curve (AUC) obtained in the permeability study with Caco-2 cells, the dissolution study and the pharmacokinetics in rabbits correlated with the cumulative AUC values in humans. These results demonstrated a direct relation between in vitro data and absorption, both in humans and in the in vivo model. Conclusions: The analytical methods and procedures applied to the development of an IVIVC model showed a strong correlation among themselves. These IVIVC models are proposed as alternative and cost/effective methods to evaluate the biopharmaceutical properties that determine the bioavailability of a drug and their application includes the development process, quality assurance, bioequivalence studies and pharmacosurveillance. PMID:26600625

  19. New anti-malarial phenylpropanoid conjugated iridoids from Morinda morindoides.

    PubMed

    Tamura, Satoru; Kubata, Bruno Kilunga; Syamsurizal; Itagaki, Sawako; Horii, Toshihiro; Taba, Muzele Kalulu; Murakami, Nobutoshi

    2010-03-01

    A new phenylpropanoid conjugated iridoid together with four known congeners was isolated from Morinda morindoides, used for the therapy of malaria traditionally in some African countries, as anti-malarial principles through bioassay-guided separation. Furthermore, their absolute stereostructures were unambiguously established by a combination of modified Mosher's method and chemical correlation.

  20. Preparation and antimalarial activity of semisynthetic lycorenine derivatives.

    PubMed

    Cedrón, Juan C; Gutiérrez, David; Flores, Ninoska; Ravelo, Ángel G; Estévez-Braun, Ana

    2013-05-01

    A set of twenty one lycorenine derivatives has been prepared from the alkaloid hippeastrine (1). The modifications performed on hippeastrine included some functional group transformations, structural simplification and preparation of dimers. All alkaloids were tested as potential antimalarial agents, being the hippeastrine dimers the most active compounds.

  1. Differences in malaria care seeking and dispensing outcomes for adults and children attending drug vendors in Nasarawa, Nigeria

    PubMed Central

    Liu, Jenny; Isiguzo, Chinwoke; Sieverding, Maia

    2015-01-01

    Objectives To characterise the differences in care seeking behaviour and dispensing outcomes between adults and children purchasing drugs for malaria at retail shops in Nigeria. Methods In Nasarawa State, retail drug shops were enumerated and a subset of those stocking antimalarials were selected as study sites and surveyed. Customers exiting shops after purchasing antimalarial drugs were surveyed and tested with a malaria rapid diagnostic test. Sick adults and caregivers accompanying sick children were eligible, but individuals purchasing drugs for a sick person that was not present were excluded. Multivariate regression analysis was used to identify the correlates of care seeking and the quality of interaction at the shop. Results Of 737 participants, 80% were adults and 20% were children (under age 18). Caregivers of sick children were more likely to obtain a prescription prior to attending a drug retailer than adults seeking care for themselves and waited a shorter time before seeking care. Caregivers of sick children were also more likely than sick adults to have been asked about symptoms by the retailer, to have been given an examination, and to have purchased an ACT. Fewer than half of respondents had purchased an ACT. Only 14% of adults, but 27% of children were RDT-positive; RDT-positive children were more likely to have had an ACT purchased for them than RDT-positive adults. Conclusions Children with suspected malaria tend to receive better care at drug retailers than adults. The degree of overtreatment and prevalence of dispensing non-recommended antimalarials emphasise the need for routine diagnosis before treatment to properly treat both malaria and non-malaria illnesses. PMID:25877471

  2. Influence of LAR and VAR on Para-Aminopyridine Antimalarials Targetting Haematin in Chloroquine-Resistance

    PubMed Central

    Warhurst, David C.; Craig, John C.

    2016-01-01

    Antimalarial chloroquine (CQ) prevents haematin detoxication when CQ-base concentrates in the acidic digestive vacuole through protonation of its p-aminopyridine (pAP) basic aromatic nitrogen and sidechain diethyl-N. CQ export through the variant vacuolar membrane export channel, PFCRT, causes CQ-resistance in Plasmodium falciparum but 3-methyl CQ (sontochin SC), des-ethyl amodiaquine (DAQ) and bis 4-aminoquinoline piperaquine (PQ) are still active. This is determined by changes in drug accumulation ratios in parasite lipid (LAR) and in vacuolar water (VAR). Higher LAR may facilitate drug binding to and blocking PFCRT and also aid haematin in lipid to bind drug. LAR for CQ is only 8.3; VAR is 143,482. More hydrophobic SC has LAR 143; VAR remains 68,523. Similarly DAQ with a phenol substituent has LAR of 40.8, with VAR 89,366. In PQ, basicity of each pAP is reduced by distal piperazine N, allowing very high LAR of 973,492, retaining VAR of 104,378. In another bis quinoline, dichlorquinazine (DCQ), also active but clinically unsatisfactory, each pAP retains basicity, being insulated by a 2-carbon chain from a proximal nitrogen of the single linking piperazine. While LAR of 15,488 is still high, the lowest estimate of VAR approaches 4.9 million. DCQ may be expected to be very highly lysosomotropic and therefore potentially hepatotoxic. In 11 pAP antimalarials a quadratic relationship between logLAR and logResistance Index (RI) was confirmed, while log (LAR/VAR) vs logRI for 12 was linear. Both might be used to predict the utility of structural modifications. PMID:27483471

  3. Influence of LAR and VAR on Para-Aminopyridine Antimalarials Targetting Haematin in Chloroquine-Resistance.

    PubMed

    Warhurst, David C; Craig, John C; Raheem, K Saki

    2016-01-01

    Antimalarial chloroquine (CQ) prevents haematin detoxication when CQ-base concentrates in the acidic digestive vacuole through protonation of its p-aminopyridine (pAP) basic aromatic nitrogen and sidechain diethyl-N. CQ export through the variant vacuolar membrane export channel, PFCRT, causes CQ-resistance in Plasmodium falciparum but 3-methyl CQ (sontochin SC), des-ethyl amodiaquine (DAQ) and bis 4-aminoquinoline piperaquine (PQ) are still active. This is determined by changes in drug accumulation ratios in parasite lipid (LAR) and in vacuolar water (VAR). Higher LAR may facilitate drug binding to and blocking PFCRT and also aid haematin in lipid to bind drug. LAR for CQ is only 8.3; VAR is 143,482. More hydrophobic SC has LAR 143; VAR remains 68,523. Similarly DAQ with a phenol substituent has LAR of 40.8, with VAR 89,366. In PQ, basicity of each pAP is reduced by distal piperazine N, allowing very high LAR of 973,492, retaining VAR of 104,378. In another bis quinoline, dichlorquinazine (DCQ), also active but clinically unsatisfactory, each pAP retains basicity, being insulated by a 2-carbon chain from a proximal nitrogen of the single linking piperazine. While LAR of 15,488 is still high, the lowest estimate of VAR approaches 4.9 million. DCQ may be expected to be very highly lysosomotropic and therefore potentially hepatotoxic. In 11 pAP antimalarials a quadratic relationship between logLAR and logResistance Index (RI) was confirmed, while log (LAR/VAR) vs logRI for 12 was linear. Both might be used to predict the utility of structural modifications. PMID:27483471

  4. Antiretroviral Choice for HIV Impacts Antimalarial Exposure and Treatment Outcomes in Ugandan Children

    PubMed Central

    Parikh, Sunil; Kajubi, Richard; Huang, Liusheng; Ssebuliba, Joshua; Kiconco, Sylvia; Gao, Qin; Li, Fangyong; Were, Moses; Kakuru, Abel; Achan, Jane; Mwebaza, Norah; Aweeka, Francesca T.

    2016-01-01

    Background. The optimal treatment of malaria in human immunodeficiency virus (HIV)–infected children requires consideration of critical drug–drug interactions in coinfected children, as these may significantly impact drug exposure and clinical outcomes. Methods. We conducted an intensive and sparse pharmacokinetic/pharmacodynamic study in Uganda of the most widely adopted artemisinin-based combination therapy, artemether-lumefantrine. HIV-infected children on 3 different first-line antiretroviral therapy (ART) regimens were compared to HIV-uninfected children not on ART, all of whom required treatment for Plasmodium falciparum malaria. Pharmacokinetic sampling for artemether, dihydroartemisinin, and lumefantrine exposure was conducted through day 21, and associations between drug exposure and outcomes through day 42 were investigated. Results. One hundred forty-five and 225 children were included in the intensive and sparse pharmacokinetic analyses, respectively. Compared with no ART, efavirenz (EFV) reduced exposure to all antimalarial components by 2.1- to 3.4-fold; lopinavir/ritonavir (LPV/r) increased lumefantrine exposure by 2.1-fold; and nevirapine reduced artemether exposure only. Day 7 concentrations of lumefantrine were 10-fold lower in children on EFV vs LPV/r-based ART, changes that were associated with an approximate 4-fold higher odds of recurrent malaria by day 28 in those on EFV vs LPV/r-based ART. Conclusions. The choice of ART in children living in a malaria-endemic region has highly significant impacts on the pharmacokinetics and pharmacodynamics of artemether-lumefantrine treatment. EFV-based ART reduces all antimalarial components and is associated with the highest risk of recurrent malaria following treatment. For those on EFV, close clinical follow-up for recurrent malaria following artemether-lumefantrine treatment, along with the study of modified dosing regimens that provide higher exposure, is warranted. PMID:27143666

  5. Anti-malarial Activities of Two Soil Actinomycete Isolates from Sabah via Inhibition of Glycogen Synthase Kinase 3β

    PubMed Central

    Dahari, Dhiana Efani; Salleh, Raifana Mohamad; Mahmud, Fauze; Chin, Lee Ping; Embi, Noor; Sidek, Hasidah Mohd

    2016-01-01

    Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition

  6. Anti-malarial Activities of Two Soil Actinomycete Isolates from Sabah via Inhibition of Glycogen Synthase Kinase 3β.

    PubMed

    Dahari, Dhiana Efani; Salleh, Raifana Mohamad; Mahmud, Fauze; Chin, Lee Ping; Embi, Noor; Sidek, Hasidah Mohd

    2016-08-01

    Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition

  7. Anti-malarial Activities of Two Soil Actinomycete Isolates from Sabah via Inhibition of Glycogen Synthase Kinase 3β

    PubMed Central

    Dahari, Dhiana Efani; Salleh, Raifana Mohamad; Mahmud, Fauze; Chin, Lee Ping; Embi, Noor; Sidek, Hasidah Mohd

    2016-01-01

    Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition

  8. Natural products as starting points for future anti-malarial therapies: going back to our roots?

    PubMed Central

    2011-01-01

    Background The discovery and development of new anti-malarials are at a crossroads. Fixed dose artemisinin combination therapy is now being used to treat a hundred million children each year, with a cost as low as 30 cents per child, with cure rates of over 95%. However, as with all anti-infective strategies, this triumph brings with it the seeds of its own downfall, the emergence of resistance. It takes ten years to develop a new medicine. New classes of medicines to combat malaria, as a result of infection by Plasmodium falciparum and Plasmodium vivax are urgently needed. Results Natural product scaffolds have been the basis of the majority of current anti-malarial medicines. Molecules such as quinine, lapachol and artemisinin were originally isolated from herbal medicinal products. After improvement with medicinal chemistry and formulation technologies, and combination with other active ingredients, they now make up the current armamentarium of medicines. In recent years advances in screening technologies have allowed testing of millions of compounds from pharmaceutical diversity for anti-malarial activity in cellular assays. These initiatives have resulted in thousands of new sub-micromolar active compounds – starting points for new drug discovery programmes. Against this backdrop, the paucity of potent natural products identified has been disappointing. Now is a good time to reflect on the current approach to screening herbal medicinal products and suggest revisions. Nearly sixty years ago, the Chinese doctor Chen Guofu, suggested natural products should be approached by dao-xing-ni-shi or ‘acting in the reversed order’, starting with observational clinical studies. Natural products based on herbal remedies are in use in the community, and have the potential unique advantage that clinical observational data exist, or can be generated. The first step should be the confirmation and definition of the clinical activity of herbal medicinal products already

  9. Injection Drug User Quality of Life Scale (IDUQOL): Findings from a content validation study

    PubMed Central

    Hubley, Anita M; Palepu, Anita

    2007-01-01

    Background Quality of life studies among injection drug users have primarily focused on health-related measures. The chaotic life-style of many injection drug users (IDUs), however, extends far beyond their health, and impacts upon social relationships, employment opportunities, housing, and day to day survival. Most current quality of life instruments do not capture the realities of people living with addictions. The Injection Drug Users' Quality of Life Scale (IDUQOL) was developed to reflect the life areas of relevance to IDUs. The present study examined the content validity of the IDUQOL using judgmental methods based on subject matter experts' (SMEs) ratings of various elements of this measure (e.g., appropriateness of life areas or items, names and descriptions of life areas, instructions for administration and scoring). Methods Six SMEs were provided with a copy of the IDUQOL and its administration and scoring manual and a detailed content validation questionnaire. Two commonly used judgmental measures of inter-rater agreement, the Content Validity Index (CVI) and the Average Deviation Mean Index (ADM), were used to evaluate SMEs' agreement on ratings of IDUQOL elements. Results A total of 75 elements of the IDUQOL were examined. The CVI results showed that all elements were endorsed by the required number of SMEs or more. The ADM results showed that acceptable agreement (i.e., practical significance) was obtained for all elements but statistically significant agreement was missed for nine elements. For these elements, SMEs' feedback was examined for ways to improve the elements. Open-ended feedback also provided suggestions for other revisions to the IDUQOL. Conclusion The results of the study provided strong evidence in support of the content validity of the IDUQOL and direction for the revision of some IDUQOL elements. PMID:17663783

  10. A pilot study on quality of artesunate and amodiaquine tablets used in the fishing community of Tema, Ghana

    PubMed Central

    2013-01-01

    Background The ineffectiveness of artesunate and amodiaquine tablets in malaria treatment remains a health burden to WHO and governments of malaria-endemic countries, including Ghana. The proliferation of illegitimate anti-malarial drugs and its use by patients is of primary concern to international and local drug regulatory agencies because such drugs are known to contribute to the development of the malaria-resistant parasites in humans. No data exist on quality of these drugs in the fishing village communities in Ghana although the villagers are likely users of such drugs. A pilot study on the quality of anti-malarial tablets in circulation during the major fishing season at a malarious fishing village located along the coast of Tema in southern Ghana was determined. Methods Blisterpacks of anti-malarial tablets were randomly sampled. The International Pharmacopoeia and Global Pharma Health Fund Minilab protocols were used to assess the quality of anti-malarial tablets per blisterpacks allegedly manufactured by Guilin Pharmaceutical Co Ltd, China (GPCL) and Letap Pharmaceuticals Ltd, Ghana (LPL) and sold in chemical sales outlets at Kpone-on–Sea. Ferric chloride and cobaltous thiocyanate tests confirmed the presence of active ingredients in the tablets. A confirmatory test for the active ingredient was achieved with artesunate (ICRS1409) and amodiaquine (ICRS0209) reference standards. A high performance liquid chromatography analysis confirmed the amount of artesunate found in tablets. Results Based on the International Pharmacopoeia acceptable range of 96/98 to 102% for genuine artesunate per tablet, 10% [relative standard deviation (RSD): 3.2%] of field-selected artesunate blisterpack per tablets manufactured by GPCL, and 50% (RSD: 5.1%) of a similar package per tablet by LPL, passed the titrimetric test. However, 100% (RSD: 2.2%) of amodiaquine blisterpack per tablet by GPCL were found to be within the International Pharmacopeia acceptable range of 90 to

  11. "This body does not want free medicines": South African consumer perceptions of drug quality.

    PubMed

    Patel, Aarti; Gauld, Robin; Norris, Pauline; Rades, Thomas

    2010-01-01

    OBJECTIVES Like many other developing countries, South Africa provides free medicines through its public health care facilities. Recent policies encourage generic substitution in the private sector. This study explored South African consumer perceptions of drug quality and whether these perceptions influenced how people procured and used their medicines. METHODS The study was undertaken in Durban, Cape Town and Johannesburg in South Africa between December 2005 and January 2006. A combination of purposive and snowball sampling was used to recruit participants from low and middle socio-economic groups as well as the elderly and teenagers. Data were collected through 12 focus group discussions involving a total of 73 participants. Interviews were tape-recorded. Thematic analysis was performed on the transcripts. RESULTS Irrespective of socio-economic status, respondents described medicine quality in terms of the effect the medicine produced on felt symptoms. Generic medicines, as well as medicines supplied without charge by the state, were considered to be poor quality and treated with suspicion. Respondents obtained medicines from three sources: public sector hospitals and/or clinics, dispensing doctors and community pharmacies. Cost, avoidance of feeling 'second-class', receiving individualized care and choice in drug selection were the main determinants influencing their procurement behaviour. Selection of over-the-counter medicines was influenced by prior knowledge of products, through advertising and previous use. Participants perceived that they had limited influence on selection of prescription medicines. Generic substitution would be supported if the doctor, rather than the pharmacist, recommended it. CONCLUSIONS Our findings emphasize the importance of meaningful consumer involvement in the development of national medicines policies, and strategic campaigns targeting consumers and prescribers regarding the quality of generic and essential medicines. Where

  12. "This body does not want free medicines": South African consumer perceptions of drug quality.

    PubMed

    Patel, Aarti; Gauld, Robin; Norris, Pauline; Rades, Thomas

    2010-01-01

    OBJECTIVES Like many other developing countries, South Africa provides free medicines through its public health care facilities. Recent policies encourage generic substitution in the private sector. This study explored South African consumer perceptions of drug quality and whether these perceptions influenced how people procured and used their medicines. METHODS The study was undertaken in Durban, Cape Town and Johannesburg in South Africa between December 2005 and January 2006. A combination of purposive and snowball sampling was used to recruit participants from low and middle socio-economic groups as well as the elderly and teenagers. Data were collected through 12 focus group discussions involving a total of 73 participants. Interviews were tape-recorded. Thematic analysis was performed on the transcripts. RESULTS Irrespective of socio-economic status, respondents described medicine quality in terms of the effect the medicine produced on felt symptoms. Generic medicines, as well as medicines supplied without charge by the state, were considered to be poor quality and treated with suspicion. Respondents obtained medicines from three sources: public sector hospitals and/or clinics, dispensing doctors and community pharmacies. Cost, avoidance of feeling 'second-class', receiving individualized care and choice in drug selection were the main determinants influencing their procurement behaviour. Selection of over-the-counter medicines was influenced by prior knowledge of products, through advertising and previous use. Participants perceived that they had limited influence on selection of prescription medicines. Generic substitution would be supported if the doctor, rather than the pharmacist, recommended it. CONCLUSIONS Our findings emphasize the importance of meaningful consumer involvement in the development of national medicines policies, and strategic campaigns targeting consumers and prescribers regarding the quality of generic and essential medicines. Where

  13. Quality of chloroquine tablets available in Africa

    PubMed Central

    SAWADOGO, C W; AMOOD AL-KAMARANY, M; AL-MEKHLAFI, H M; ELKARBANE, M; AL-ADHROEY, A H; CHERRAH, Y; BOUKLOUZE, A

    2011-01-01

    Malaria is the biggest killer of African children, yet it is cheaply preventable and curable with insecticides spraying, impregnated bednets and effective drugs. This study aimed to evaluate the quality of Chloroquine (CQ) tablets available in selected African countries. Twenty-six samples of antimalarial CQ tablet of 100, 150 and 250 mg were collected from 12 African countries and evaluated for their quality in the Drugs Quality Control Laboratory of Rabat, Morocco. The identification and dosage of active pharmaceutical ingredients in the tablets, dissolution rate, hardness and the friability of CQ tablets were performed according to the United States Pharmacopeia (USP) and European Pharmacopoeia (Eur.Ph.) recommended methods. The results showed that 7.7% of the sampled CQ tablets available in Burkina Faso were of low quality. Failure in dissolution profile was found in 50% of CQ tablets sampled from Benin, Burkina Faso, Comoros Union, Mali and Senegal. The findings showed poor quality of CQ tablets available in the African market. This problem may affect the efforts to control malaria in Africa. Efficient regulatory systems of drugs quality control should be implemented. PMID:22117854

  14. Discovery of new antimalarial chemotypes through chemical methodology and library development.

    PubMed

    Brown, Lauren E; Chih-Chien Cheng, Ken; Wei, Wan-Guo; Yuan, Pingwei; Dai, Peng; Trilles, Richard; Ni, Feng; Yuan, Jing; MacArthur, Ryan; Guha, Rajarshi; Johnson, Ronald L; Su, Xin-zhuan; Dominguez, Melissa M; Snyder, John K; Beeler, Aaron B; Schaus, Scott E; Inglese, James; Porco, John A

    2011-04-26

    In an effort to expand the stereochemical and structural complexity of chemical libraries used in drug discovery, the Center for Chemical Methodology and Library Development at Boston University has established an infrastructure to translate methodologies accessing diverse chemotypes into arrayed libraries for biological evaluation. In a collaborative effort, the NIH Chemical Genomics Center determined IC(50)'s for Plasmodium falciparum viability for each of 2,070 members of the CMLD-BU compound collection using quantitative high-throughput screening across five parasite lines of distinct geographic origin. Three compound classes displaying either differential or comprehensive antimalarial activity across the lines were identified, and the nascent structure activity relationships (SAR) from this experiment used to initiate optimization of these chemotypes for further development.

  15. The anti-malarial atovaquone increases radiosensitivity by alleviating tumour hypoxia.

    PubMed

    Ashton, Thomas M; Fokas, Emmanouil; Kunz-Schughart, Leoni A; Folkes, Lisa K; Anbalagan, Selvakumar; Huether, Melanie; Kelly, Catherine J; Pirovano, Giacomo; Buffa, Francesca M; Hammond, Ester M; Stratford, Michael; Muschel, Ruth J; Higgins, Geoff S; McKenna, William Gillies

    2016-01-01

    Tumour hypoxia renders cancer cells resistant to cancer therapy, resulting in markedly worse clinical outcomes. To find clinical candidate compounds that reduce hypoxia in tumours, we conduct a high-throughput screen for oxygen consumption rate (OCR) reduction and identify a number of drugs with this property. For this study we focus on the anti-malarial, atovaquone. Atovaquone rapidly decreases the OCR by more than 80% in a wide range of cancer cell lines at pharmacological concentrations. In addition, atovaquone eradicates hypoxia in FaDu, HCT116 and H1299 spheroids. Similarly, it reduces hypoxia in FaDu and HCT116 xenografts in nude mice, and causes a significant tumour growth delay when combined with radiation. Atovaquone is a ubiquinone analogue, and decreases the OCR by inhibiting mitochondrial complex III. We are now undertaking clinical studies to assess whether atovaquone reduces tumour hypoxia in patients, thereby increasing the efficacy of radiotherapy. PMID:27453292

  16. The anti-malarial atovaquone increases radiosensitivity by alleviating tumour hypoxia

    PubMed Central

    Ashton, Thomas M.; Fokas, Emmanouil; Kunz-Schughart, Leoni A.; Folkes, Lisa K.; Anbalagan, Selvakumar; Huether, Melanie; Kelly, Catherine J.; Pirovano, Giacomo; Buffa, Francesca M.; Hammond, Ester M.; Stratford, Michael; Muschel, Ruth J.; Higgins, Geoff S.; McKenna, William Gillies

    2016-01-01

    Tumour hypoxia renders cancer cells resistant to cancer therapy, resulting in markedly worse clinical outcomes. To find clinical candidate compounds that reduce hypoxia in tumours, we conduct a high-throughput screen for oxygen consumption rate (OCR) reduction and identify a number of drugs with this property. For this study we focus on the anti-malarial, atovaquone. Atovaquone rapidly decreases the OCR by more than 80% in a wide range of cancer cell lines at pharmacological concentrations. In addition, atovaquone eradicates hypoxia in FaDu, HCT116 and H1299 spheroids. Similarly, it reduces hypoxia in FaDu and HCT116 xenografts in nude mice, and causes a significant tumour growth delay when combined with radiation. Atovaquone is a ubiquinone analogue, and decreases the OCR by inhibiting mitochondrial complex III. We are now undertaking clinical studies to assess whether atovaquone reduces tumour hypoxia in patients, thereby increasing the efficacy of radiotherapy. PMID:27453292

  17. Application of Absorption Modeling in Rational Design of Drug Product Under Quality-by-Design Paradigm.

    PubMed

    Kesisoglou, Filippos; Mitra, Amitava

    2015-09-01

    Physiologically based absorption models can be an important tool in understanding product performance and hence implementation of Quality by Design (QbD) in drug product development. In this report, we show several case studies to demonstrate the potential application of absorption modeling in rational design of drug product under the QbD paradigm. The examples include application of absorption modeling—(1) prior to first-in-human studies to guide development of a formulation with minimal sensitivity to higher gastric pH and hence reduced interaction when co-administered with PPIs and/or H2RAs, (2) design of a controlled release formulation with optimal release rate to meet trough plasma concentrations and enable QD dosing, (3) understanding the impact of API particle size distribution on tablet bioavailability and guide formulation design in late-stage development, (4) assess impact of API phase change on product performance to guide specification setting, and (5) investigate the effect of dissolution rate changes on formulation bioperformance and enable appropriate specification setting. These case studies are meant to highlight the utility of physiologically based absorption modeling in gaining a thorough understanding of the product performance and the critical factors impacting performance to drive design of a robust drug product that would deliver the optimal benefit to the patients.

  18. Antimalarial activity of artefenomel (OZ439), a novel synthetic antimalarial endoperoxide, in patients with Plasmodium falciparum and Plasmodium vivax malaria: an open-label phase 2 trial

    PubMed Central

    Phyo, Aung Pyae; Jittamala, Podjanee; Nosten, François H; Pukrittayakamee, Sasithon; Imwong, Mallika; White, Nicholas J; Duparc, Stephan; Macintyre, Fiona; Baker, Mark; Möhrle, Jörg J

    2016-01-01

    Summary Background Artefenomel (OZ439) is a novel synthetic trioxolane with improved pharmacokinetic properties compared with other antimalarial drugs with the artemisinin pharmacophore. Artefenomel has been generally well tolerated in volunteers at doses up to 1600 mg and is being developed as a partner drug in an antimalarial combination treatment. We investigated the efficacy, tolerability, and pharmacokinetics of artefenomel at different doses in patients with Plasmodium falciparum or Plasmodium vivax malaria. Methods This phase 2a exploratory, open-label trial was done at the Hospital for Tropical Diseases, Bangkok, and the Shoklo Malaria Research Unit in Thailand. Adult patients with acute, uncomplicated P falciparum or P vivax malaria received artefenomel in a single oral dose (200 mg, 400 mg, 800 mg, or 1200 mg). The first cohort received 800 mg. Testing of a new dose of artefenomel in a patient cohort was decided on after safety and efficacy assessment of the preceding cohort. The primary endpoint was the natural log parasite reduction per 24 h. Definitive oral treatment was given at 36 h. This trial is registered with ClinicalTrials.gov, number NCT01213966. Findings Between Oct 24, 2010, and May 25, 2012, 82 patients were enrolled (20 in each of the 200 mg, 400 mg, and 800 mg cohorts, and 21 in the 1200 mg cohort). One patient withdrew consent (before the administration of artefenomel) but there were no further dropouts. The parasite reduction rates per 24 h ranged from 0·90 to 1·88 for P falciparum, and 2·09 to 2·53 for P vivax. All doses were equally effective in both P falciparum and P vivax malaria, with median parasite clearance half-lives of 4·1 h (range 1·3–6·7) to 5·6 h (2·0–8·5) for P falciparum and 2·3 h (1·2–3·9) to 3·2 h (0·9–15·0) for P vivax. Maximum plasma concentrations, dose-proportional to 800 mg, occurred at 4 h (median). The estimated elimination half-life was 46–62 h. No serious drug-related adverse effects

  19. In Vivo Antimalarial Activity of Annona muricata Leaf Extract in Mice Infected with Plasmodium berghei.

    PubMed

    Somsak, Voravuth; Polwiang, Natsuda; Chachiyo, Sukanya

    2016-01-01

    Malaria is one of the most important infectious diseases in the world. The choice for the treatment is highly limited due to drug resistance. Hence, finding the new compounds to treat malaria is urgently needed. The present study was attempted to evaluate the antimalarial activity of the Annona muricata aqueous leaf extract in Plasmodium berghei infected mice. Aqueous leaf extract of A. muricata was prepared and tested for acute toxicity in mice. For efficacy test in vivo, standard 4-day suppressive test was carried out. ICR mice were inoculated with 10(7) parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection. The extracts (100, 500, and 1000 mg/kg) were then given orally by gavage once a day for 4 consecutive days. Parasitemia, percentage of inhibition, and packed cell volume were subsequently calculated. Chloroquine (10 mg/kg) was given to infected mice as positive control while untreated control was given only distilled water. It was found that A. muricata aqueous leaf extract at doses of 100, 500, and 1000 mg/kg resulted in dose dependent parasitemia inhibition of 38.03%, 75.25%, and 85.61%, respectively. Survival time was prolonged in infected mice treated with the extract. Moreover, no mortality to mice was observed with this extract up to a dose of 4000 mg/kg. In conclusion, the A. muricata aqueous leaf extract exerted significant antimalarial activity with no toxicity and prolonged survival time. Therefore, this extract might contain potential lead molecule for the development of a new drug for malaria treatment.

  20. In Vivo Antimalarial Activity of Annona muricata Leaf Extract in Mice Infected with Plasmodium berghei

    PubMed Central

    Somsak, Voravuth; Polwiang, Natsuda; Chachiyo, Sukanya

    2016-01-01

    Malaria is one of the most important infectious diseases in the world. The choice for the treatment is highly limited due to drug resistance. Hence, finding the new compounds to treat malaria is urgently needed. The present study was attempted to evaluate the antimalarial activity of the Annona muricata aqueous leaf extract in Plasmodium berghei infected mice. Aqueous leaf extract of A. muricata was prepared and tested for acute toxicity in mice. For efficacy test in vivo, standard 4-day suppressive test was carried out. ICR mice were inoculated with 107 parasitized erythrocytes of P. berghei ANKA by intraperitoneal injection. The extracts (100, 500, and 1000 mg/kg) were then given orally by gavage once a day for 4 consecutive days. Parasitemia, percentage of inhibition, and packed cell volume were subsequently calculated. Chloroquine (10 mg/kg) was given to infected mice as positive control while untreated control was given only distilled water. It was found that A. muricata aqueous leaf extract at doses of 100, 500, and 1000 mg/kg resulted in dose dependent parasitemia inhibition of 38.03%, 75.25%, and 85.61%, respectively. Survival time was prolonged in infected mice treated with the extract. Moreover, no mortality to mice was observed with this extract up to a dose of 4000 mg/kg. In conclusion, the A. muricata aqueous leaf extract exerted significant antimalarial activity with no toxicity and prolonged survival time. Therefore, this extract might contain potential lead molecule for the development of a new drug for malaria treatment. PMID:27092277

  1. Identification of novel class of falcipain-2 inhibitors as potential antimalarial agents.

    PubMed

    Chakka, Sai Kumar; Kalamuddin, Mohammad; Sundararaman, Srividhya; Wei, Lianhu; Mundra, Sourabh; Mahesh, Radhakrishnan; Malhotra, Pawan; Mohmmed, Asif; Kotra, Lakshmi P

    2015-05-01

    Falcipain-2 is a papain family cysteine protease and an emerging antimalarial drug target. A pseudo-tripeptide scaffold I was designed using in silico screening tools and the three dimensional structures of falcipain-2, falcipain-3, and papain. This scaffold was investigated at four positions, T1, T2, T3, and T3', with various targeted substitutions to understand the structure-activity relationships. Inhibitor synthesis was accomplished by first obtaining the appropriate dipeptide precursors with common structural components. The pyrrolidine moiety introduced interesting rotamers in a number of synthesized molecules, which was confirmed using high-temperature (1)H NMR spectroscopy. Among the synthesized compounds, 61, 62, and 66 inhibited falcipain-2 activity with inhibition constants (Ki) of 1.8 ± 1.1, 0.2 ± 0.1 and 7.0 ± 2.3 μM, respectively. A group of molecules with a pyrrolidine moiety at the T2 position (68, 70, 71, 72, and 73) also potently inhibited falcipain-2 activity (Ki=0.4 ± 0.1, 2.5 ± 0.5, 3.3 ± 1.1, 7.5 ± 1.9, and 4.6 ± 0.7 μM, respectively). Overall, compound 74 exhibited potent anti-parasitic activity (IC₅₀=0.9 ± 0.1 μM), corresponding with its inhibitory activity against falcipain-2, with a Ki of 1.1 ± 0.1 μM. Compounds 62 and 67 inhibited the growth of the drug resistant parasite Dd2 with better efficacy, and compound 74 exhibited a 7- to 12-fold higher potency against Dd2 and MCamp isolates, than the laboratory strain (3D7). These data suggest that this novel series of compounds should be further investigated as potential antimalarial agents. PMID:25840796

  2. Drugs.

    ERIC Educational Resources Information Center

    Hurst, Hunter, Ed.; And Others

    1984-01-01

    This document contains the third volume of "Today's Delinquent," an annual publication of the National Center for Juvenile Justice. This volume deals with the issue of drugs and includes articles by leading authorities in delinquency and substance abuse who share their views on causes and cures for the drug problem among youth in this country.…

  3. Non-stochastic quadratic fingerprints and LDA-based QSAR models in hit and lead generation through virtual screening: theoretical and experimental assessment of a promising method for the discovery of new antimalarial compounds.

    PubMed

    Montero-Torres, Alina; García-Sánchez, Rory N; Marrero-Ponce, Yovani; Machado-Tugores, Yanetsy; Nogal-Ruiz, Juan J; Martínez-Fernández, Antonio R; Arán, Vicente J; Ochoa, Carmen; Meneses-Marcel, Alfredo; Torrens, Francisco

    2006-04-01

    In order to explore the ability of non-stochastic quadratic indices to encode chemical information in antimalarials, four quantitative models for the discrimination of compounds having this property were generated and statistically compared. Accuracies of 90.2% and 83.3% for the training and test sets, respectively, were observed for the best of all the models, which included non-stochastic quadratic fingerprints weighted with Pauling electronegativities. With a comparative purpose and as a second validation experiment, an exercise of virtual screening of 65 already-reported antimalarials was carried out. Finally, 17 new compounds were classified as either active/inactive ones and experimentally evaluated for their potential antimalarial properties on the ferriprotoporphyrin (FP) IX biocrystallization inhibition test (FBIT). The theoretical predictions were in agreement with the experimental results. In the assayed test compound C5 resulted more active than chloroquine. The current result illustrates the usefulness of the TOMOCOMD-CARDD strategy in rational antimalarial-drug design, at the time that it introduces a new family of organic compounds as starting point for the development of promising antimalarials.

  4. [Definition of priority medicines for monitoring laboratory quality in Brazil: the interface between health surveillance and the National Drug Policy].

    PubMed

    Pontes Junior, Durval Martins; Pepe, Vera Lúcia Edais; Osorio-de-Castro, Claudia Garcia Serpa; Massena, Elisa Prestes; Portela, Margareth Crisóstomo; Miranda, Maria do Carmo; Silva, Raulino Sabino da

    2008-09-01

    A key objective of the Brazilian National Drug Policy is the quality of medicines supplied to the population. This study aimed to set priorities for the analysis of the National Program for Quality Control of Medicines. The main criterion was the drug's presence in at least three Pharmaceutical Care Programs under the Ministry of Health. Additional criteria were presence on the National List of Essential Drugs (RENAME) in 2002 and its indication for the 20 main causes of disability-adjusted life years (DALY). The sources were data from the Ministry of Health and related legislation. The drugs were classified according to the Anatomical Therapeutic Chemical Classification System (ATC) of the WHO. The 13 pharmaceutical care programs included 893 products classified in 449 different ATC codes. Twenty-eight drugs were considered priorities, 26 of which were listed on the RENAME and 12 indicated as causes of DALY. It is recommended that the National Health Surveillance Agency and Secretariat of Science, Technology, and Strategic Inputs establish an integrated strategy to guarantee comprehensive quality of these drugs, including laboratory quality, registration, good manufacturing practices, and information for health professionals and the general population.

  5. Plasmodium Drug Targets Outside the Genetic Control of the Parasite

    PubMed Central

    Sullivan, David J.

    2014-01-01

    Drug development often seeks to find “magic bullets” which target microbiologic proteins while not affecting host proteins. Paul Ehrlich tested methylene blue as an antimalarial but this dye was not superior to quinine. Many successful antimalarial therapies are “magic shotguns” which target many Plasmodium pathways with little interference in host metabolism. Two malaria drug classes, the 8-aminoquinolines and the artemisinins interact with cytochrome P450s and host iron protoporphyrin IX or iron, respectively, to generate toxic metabolites and/or radicals, which kill the parasite by interference with many proteins. The non 8-amino antimalarial quinolines like quinine or piperaquine bind heme to inhibit the process of heme crystallization, which results in multiple enzyme inhibition and membrane dysfunction. The quinolines and artemisinins are rapidly parasiticidal in contrast to metal chelators, which have a slower parasite clearance rate with higher drug concentrations. Iron chelators interfere with the artemisinins but otherwise represent a strategy of targeting multiple enzymes containing iron. Interest has been revived in antineoplastic drugs that target DNA metabolism as antimalarials. Specific drug targeting or investigation of the innate immunity directed to the more permeable trophozoite or schizont infected erythrocyte membrane has been under explored. Novel drug classes in the antimalarial development pipeline which either target multiple proteins or unchangeable cellular targets will slow the pace of drug resistance acquisition. PMID:22973888

  6. Discovery and optimisation studies of antimalarial phenotypic hits

    PubMed Central

    Mital, Alka; Murugesan, Dinakaran; Kaiser, Marcel; Yeates, Clive; Gilbert, Ian H.

    2015-01-01

    There is an urgent need for the development of new antimalarial compounds. As a result of a phenotypic screen, several compounds with potent activity against the parasite Plasmodium falciparum were identified. Characterization of these compounds is discussed, along with approaches to optimise the physicochemical properties. The in vitro antimalarial activity of these compounds against P. falciparum K1 had EC50 values in the range of 0.09–29 μM, and generally good selectivity (typically >100-fold) compared to a mammalian cell line (L6). One example showed no significant activity against a rodent model of malaria, and more work is needed to optimise these compounds. PMID:26408453

  7. Hit-to-Lead Studies for the Antimalarial Tetrahydroisoquinolone Carboxanilides.

    PubMed

    Floyd, David M; Stein, Philip; Wang, Zheng; Liu, Jian; Castro, Steve; Clark, Julie A; Connelly, Michele; Zhu, Fangyi; Holbrook, Gloria; Matheny, Amy; Sigal, Martina S; Min, Jaeki; Dhinakaran, Rajkumar; Krishnan, Senthil; Bashyum, Sridevi; Knapp, Spencer; Guy, R Kiplin

    2016-09-01

    Phenotypic whole-cell screening in erythrocytic cocultures of Plasmodium falciparum identified a series of dihydroisoquinolones that possessed potent antimalarial activity against multiple resistant strains of P. falciparum in vitro and show no cytotoxicity to mammalian cells. Systematic structure-activity studies revealed relationships between potency and modifications at N-2, C-3, and C-4. Careful structure-property relationship studies, coupled with studies of metabolism, addressed the poor aqueous solubility and metabolic vulnerability, as well as potential toxicological effects, inherent in the more potent primary screening hits such as 10b. Analogues 13h and 13i, with structural modifications at each site, were shown to possess excellent antimalarial activity in vivo. The (+)-(3S,4S) enantiomer of 13i and similar analogues were identified as the more potent. On the basis of these studies, we have selected (+)-13i for further study as a preclinical candidate. PMID:27505686

  8. Methods for implementing a medicine outlet survey: lessons from the anti-malarial market

    PubMed Central

    2013-01-01

    Background In recent years an increasing number of public investments and policy changes have been made to improve the availability, affordability and quality of medicines available to consumers in developing countries, including anti-malarials. It is important to monitor the extent to which these interventions are successful in achieving their aims using quantitative data on the supply side of the market. There are a number of challenges related to studying supply, including outlet sampling, gaining provider cooperation and collecting accurate data on medicines. This paper provides guidance on key steps to address these issues when conducting a medicine outlet survey in a developing country context. While the basic principles of good survey design and implementation are important for all surveys, there are a set of specific issues that should be considered when conducting a medicine outlet survey. Methods This paper draws on the authors’ experience of designing and implementing outlet surveys, including the lessons learnt from ACTwatch outlet surveys on anti-malarial retail supply, and other key studies in the field. Key lessons and points of debate are distilled around the following areas: selecting a sample of outlets; techniques for collecting and analysing data on medicine availability, price and sales volumes; and methods for ensuring high quality data in general. Results and conclusions The authors first consider the inclusion criteria for outlets, contrasting comprehensive versus more focused approaches. Methods for developing a reliable sampling frame of outlets are then presented, including use of existing lists, key informants and an outlet census. Specific issues in the collection of data on medicine prices and sales volumes are discussed; and approaches for generating comparable price and sales volume data across products using the adult equivalent treatment dose (AETD) are explored. The paper concludes with advice on practical considerations

  9. Cytotoxic and antimalarial bisbenzylisoquinoline alkaloids from Cyclea barbata.

    PubMed

    Lin, L Z; Shieh, H L; Angerhofer, C K; Pezzuto, J M; Cordell, G A; Xue, L; Johnson, M E; Ruangrungsi, N

    1993-01-01

    An alkaloid extract derived from the roots of Cyclea barbata demonstrated cytotoxic and antimalarial activities, and five bisbenzylisoquinoline alkaloids, (+)-tetrandrine [1], (-)-limacine [2], (+)-thalrugosine [3], (+)-homoaromoline [4], and (-)-cycleapeltine [5], were isolated as the active principles. The complete and unambiguous assignments of the 1H- and 13C-nmr data of these substances were made by 1D and 2D nmr techniques (COSY, phase-sensitive ROESY, HETCOR, and FLOCK). PMID:8450318

  10. Antimalarial diterpene alkaloids from the seeds of Caesalpinia minax.

    PubMed

    Ma, Guoxu; Sun, Zhaocui; Sun, Zhonghao; Yuan, Jingquan; Wei, Hua; Yang, Junshan; Wu, Haifeng; Xu, Xudong

    2014-06-01

    Two new diterpene alkaloids, caesalminines A (1) and B (2), possessing a tetracyclic cassane-type furanoditerpenoid skeleton with γ-lactam ring, were isolated from the seeds of Caesalpinia minax. Their structures were determined by different spectroscopic methods and ECD calculation. The plausible biosynthetic pathway of caesalminines A and B was proposed. The anti-malarial activity of compounds 1 and 2 is presented with IC50 values of 0.42 and 0.79 μM, respectively.

  11. Antimalarial Activity of Cocos nucifera Husk Fibre: Further Studies

    PubMed Central

    Adebayo, J. O.; Balogun, E. A.; Malomo, S. O.; Soladoye, A. O.; Olatunji, L. A.; Kolawole, O. M.; Oguntoye, O. S.; Babatunde, A. S.; Akinola, O. B.; Aguiar, A. C. C.; Andrade, I. M.; Souza, N. B.; Krettli, A. U.

    2013-01-01

    In this study, the antimalarial and toxicity potentials of husk fibre extracts of five Nigerian varieties of Cocos nucifera were evaluated in vitro. The only active extract fraction, West African Tall (WAT) ethyl acetate extract fraction, was then evaluated for its phytochemical constituents, antimalarial and toxicity potentials at varying doses (31.25–500 mg/kg body weight) using various organ function indices. The results revealed that WAT ethyl acetate extract fraction (WATEAEF) contained alkaloids, tannins, and flavonoids and was active against Plasmodium falciparum W2 strain maintained in continuous culture, with a selectivity index of 30.3. The same extract fraction was active in vivo against Plasmodium berghei NK65, causing more than 50% reduction in parasitaemia on days 4 and 6 after inoculation at various doses administered. WATEAEF did not significantly alter (P > 0.05) function indices of the liver and cardiovascular system at all doses administered but significantly increased (P < 0.05) plasma creatinine concentration at 250 and 500 mg/Kg body weight compared to controls. The results of this study suggest that WATEAEF possesses antimalarial activity and may not adversely affect normal liver function nor predispose subjects to cardiovascular diseases but may impair normal kidney function at higher doses. Further studies are underway to isolate the active principles. PMID:23983800

  12. Review of pyronaridine anti-malarial properties and product characteristics

    PubMed Central

    2012-01-01

    Pyronaridine was synthesized in 1970 at the Institute of Chinese Parasitic Disease and has been used in China for over 30 years for the treatment of malaria. Pyronaridine has high potency against Plasmodium falciparum, including chloroquine-resistant strains. Studies in various animal models have shown pyronaridine to be effective against strains resistant to other anti-malarials, including chloroquine. Resistance to pyronaridine appears to emerge slowly and is further retarded when pyronaridine is used in combination with other anti-malarials, in particular, artesunate. Pyronaridine toxicity is generally less than that of chloroquine, though evidence of embryotoxicity in rodents suggests use with caution in pregnancy. Clinical pharmacokinetic data for pyronaridine indicates an elimination T1/2 of 13.2 and 9.6 days, respectively, in adults and children with acute uncomplicated falciparum and vivax malaria in artemisinin-combination therapy. Clinical data for mono or combined pyronaridine therapy show excellent anti-malarial effects against P. falciparum and studies of combination therapy also show promise against Plasmodium vivax. Pyronaridine has been developed as a fixed dose combination therapy, in a 3:1 ratio, with artesunate for the treatment of acute uncomplicated P. falciparum malaria and blood stage P. vivax malaria with the name of Pyramax® and has received Positive Opinion by European Medicines Agency under the Article 58 procedure. PMID:22877082

  13. Muddled mechanisms: recent progress towards antimalarial target identification

    PubMed Central

    Edwards, Rachel L.; Odom John, Audrey R.

    2016-01-01

    In the past decade, malaria rates have plummeted as a result of aggressive infection control measures and the adoption of artemisinin-based combination therapies (ACTs). However, a potential crisis looms ahead. Treatment failures to standard antimalarial regimens have been reported in Southeast Asia, and devastating consequences are expected if resistance spreads to the African continent. To prevent a potential public health emergency, the antimalarial arsenal must contain therapeutics with novel mechanisms of action (MOA). An impressive number of high-throughput screening (HTS) campaigns have since been launched, identifying thousands of compounds with activity against one of the causative agents of malaria, Plasmodium falciparum. Now begins the difficult task of target identification, for which studies are often tedious, labor intensive, and difficult to interpret. In this review, we highlight approaches that have been instrumental in tackling the challenges of target assignment and elucidation of the MOA for hit compounds. Studies that apply these innovative techniques to antimalarial target identification are described, as well as the impact of the data in the field. PMID:27803804

  14. Antimalarial and antimicrobial activities of 8-Aminoquinoline-Uracils metal complexes

    PubMed Central

    Phopin, Kamonrat; Sinthupoom, Nujarin; Treeratanapiboon, Lertyot; Kunwittaya, Sarun; Prachayasittikul, Supaluk; Ruchirawat, Somsak; Prachayasittikul, Virapong

    2016-01-01

    8-Aminoquinoline (8AQ) derivatives have been reported to have antimalarial, anticancer, and antioxidant activities. This study investigated the potency of 8AQ-5-substituted (iodo and nitro) uracils metal (Mn, Cu, Ni) complexes (1-6) as antimalarial and antimicrobial agents. Interestingly, all of these metal complexes (1-6) showed fair antimalarial activities. Moreover, Cu complexes 2 (8AQ-Cu-5Iu) and 5 (8AQ-Cu-5Nu) exerted antimicrobial activities against Gram-negative bacteria including P. shigelloides and S. dysenteriae. The results reveal application of 8AQ and its metal complexes as potential compounds to be further developed as novel antimalarial and antibacterial agents. PMID:27103894

  15. Economic access to effective drugs for falciparum malaria.

    PubMed

    Panosian, Claire B

    2005-03-01

    The increasing death toll from drug-resistant falciparum malaria is cause for international concern. In 2002, the US Agency for International Development commissioned the Institute of Medicine (IOM) to recommend global actions to ensure the broadest possible access to new, effective antimalarial treatments. In a report issued in 2004, the IOM Committee on Economics of Antimalarial Drugs recommended a global subsidy of 300 million dollars to 500 million dollars per year to replace increasingly ineffective drugs with coformulated artemisinin combination treatments to be distributed through public and private channels in affected areas. This approach allows the existing market to support the switch to new drugs and keeps treatment costs for consumers at levels similar to the current price of chloroquine. The leverage of an international subsidy of combination therapy can also discourage the distribution of monotherapies (such as solo artemisinins), the use of which might foster increasing resistance to antimalarial drugs in the future. PMID:15714418

  16. Quality by design case study: an integrated multivariate approach to drug product and process development.

    PubMed

    Huang, Jun; Kaul, Goldi; Cai, Chunsheng; Chatlapalli, Ramarao; Hernandez-Abad, Pedro; Ghosh, Krishnendu; Nagi, Arwinder

    2009-12-01

    To facilitate an in-depth process understanding, and offer opportunities for developing control strategies to ensure product quality, a combination of experimental design, optimization and multivariate techniques was integrated into the process development of a drug product. A process DOE was used to evaluate effects of the design factors on manufacturability and final product CQAs, and establish design space to ensure desired CQAs. Two types of analyses were performed to extract maximal information, DOE effect & response surface analysis and multivariate analysis (PCA and PLS). The DOE effect analysis was used to evaluate the interactions and effects of three design factors (water amount, wet massing time and lubrication time), on response variables (blend flow, compressibility and tablet dissolution). The design space was established by the combined use of DOE, optimization and multivariate analysis to ensure desired CQAs. Multivariate analysis of all variables from the DOE batches was conducted to study relationships between the variables and to evaluate the impact of material attributes/process parameters on manufacturability and final product CQAs. The integrated multivariate approach exemplifies application of QbD principles and tools to drug product and process development.

  17. 42 CFR 423.153 - Drug utilization management, quality assurance, and medication therapy management programs (MTMPs).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Screening for potential drug therapy problems due to therapeutic duplication. (ii) Age/gender-related... dosage or duration of drug therapy. (vi) Drug-allergy contraindications. (vii) Clinical abuse/misuse....

  18. Efficacy of Synriam™, a new antimalarial combination of OZ277 and piperaquine, against different developmental stages of Schistosoma mansoni.

    PubMed

    Mossallam, Shereen F; Amer, Eglal I; El-Faham, Marwa H

    2015-03-01

    Control of schistosomiasis relies on a single drug, praziquantel (PZQ). Given the rising concerns about the potential emergence of PZQ-resistant strains, it has now become necessary to search for novel therapeutics. However, the current pace for anti-schistosomal drug discovery is slow; hence, repositioning of existing approved drugs can offer a safe, rapid and cost-effective solution. The anti-malarial synthetic artemisinin-derivatives trioxolanes demonstrated anti-schistosomal efficacies against the three major species infecting humans and, unlike PZQ, showed activities against both juvenile and adult worm stages. The 1,2,4-trioxolane/OZ277 (arterolane maleate) in combination with a partner drug: piperaquine phosphate was recently developed as an anti-malarial drug and manufactured by Ranbaxy (India) as Synriam™ (SYN). Herein, the in vivo activities of SYN were investigated in a mouse model of Schistosoma mansoni (S. mansoni), compared to PZQ. We show that a single fixed dose of 240mg/kg SYN (40mg/kg arterolane and 200mg/kg piperaqine) induced significant protective effects in mice, in terms of reduction in worm and tissue egg burdens, which were evident against all schistosome developmental stages. Extensive alterations in the tegument and subtegumental tissues of SYN-exposed worms were revealed by both scanning and transmission electron microscopes. Progressive decrease in worm activity and occurrence of death were noticed in vitro upon exposure to the drug - more pronounced in the presence of haemin. This report provides the first evidence of the efficacy of a combination of 1,2,4-trioxolane and piperaquine against S. mansoni in mice. Being effective against young stages, SYN could be used to prevent early Schistosoma infection. PMID:25530543

  19. Diversity and utilization of antimalarial ethnophytotherapeutic remedies among the Kikuyus (Central Kenya)

    PubMed Central

    Njoroge, Grace N; Bussmann, Rainer W

    2006-01-01

    Plants in Kenya are becoming increasingly important as sources of traditional medicines. The World Health Organization (WHO) has estimated that malaria kills about 2.7 million people every year, 90% of who are from Africa. Malaria continues to be a national concern in Kenya as it plays a major role in the high mortality rates being experienced currently. The use and miss-use of chloroquine to prevent and treat falciparium malaria has led to widespread appearance of chloroquine resistant parasites in Kenya and other tropical countries. These factors and the rising costs of non-chloroquine drugs have made the local people to turn to traditional remedies for management of this menace. This paper examines the current utilization of traditional plant medicines in managing malaria menace in Central Kenya. The results show both indigenous and introduced species are in use indicating traditional medicinal practices in this region are dynamic. In total 58 species in 54 genera and 33 families were identified. The family Rubiaceae was found to have the highest number of reported species. Use of the various taxa is compared between five districts within Central Province of Kenya. The commonest species in this pharmacopoeia are: Caesalpinia volkensii Harms, Strychnos henningsii Gilg, Ajuga remota Benth., Warbugia ugandensis Sprague and Olea europaea L. The first three species are used in all the five districts while the others are restricted in some of the districts. In 74% of the anti-malarial plant species reported in this study, the remedies are obtained in destructive manner and may need conservation measures to ensure sustainable utilization. The results of this study become a basis for selecting plants for further pharmacological and phytochemical studies in developing new and locally relevant anti-malarial agents. PMID:16451716

  20. Effects of an antimalarial quinazoline derivative on human erythrocytes and on cell membrane molecular models.

    PubMed

    Rojas-Aguirre, Yareli; Hernández-Luis, Francisco; Mendoza-Martínez, César; Sotomayor, Carlos Patricio; Aguilar, Luis Felipe; Villena, Fernando; Castillo, Ivan; Hernández, David J; Suwalsky, Mario

    2012-03-01

    Plasmodium, the parasite which causes malaria in humans multiplies in the liver and then infects circulating erythrocytes. Thus, the role of the erythrocyte cell membrane in antimalarial drug activity and resistance has key importance. The effects of the antiplasmodial N(6)-(4-methoxybenzyl)quinazoline-2,4,6-triamine (M4), and its inclusion complex (M4/HPβCD) with 2-hydroxypropyl-β-cyclodextrin (HPβCD) on human erythrocytes and on cell membrane molecular models are herein reported. This work evidences that M4/HPβCD interacts with red cells as follows: a) in scanning electron microscopy (SEM) studies on human erythrocytes induced shape changes at a 10μM concentration; b) in isolated unsealed human erythrocyte membranes (IUM) a concentration as low as 1μM induced sharp DPH fluorescence anisotropy decrease whereas increasing concentrations produced a monotonically decrease of DPH fluorescence lifetime at 37°C; c) X-ray diffraction studies showed that 200μM induced a complete structural perturbation of dimyristoylphosphatidylcholine (DMPC) bilayers whereas no significant effects were detected in dimyristoylphosphatidylethanolamine (DMPE) bilayers, classes of lipids present in the outer and inner monolayers of the human erythrocyte membrane, respectively; d) fluorescence spectroscopy data showed that increasing concentrations of the complex interacted with the deep hydrophobic core of DMPC large unilamellar vesicles (LUV) at 18°C. All these experiments are consistent with the insertion of M4/HPβCD in the outer monolayer of the human erythrocyte membrane; thus, it can be considered a promising and novel antimalarial agent. PMID:22155684

  1. In Vitro Cardiovascular Effects of Dihydroartemisin-Piperaquine Combination Compared with Other Antimalarials

    PubMed Central

    Crumb, William; Pace, Silvia; Ubben, David; Wible, Barb; Yan, Gan-Xin; Funck-Brentano, Christian

    2012-01-01

    The in vitro cardiac properties of dihydroartemisinin (DHA) plus piperaquine phosphate (PQP) were compared with those of other antimalarial compounds. Results with antimalarial drugs, chosen on the basis of their free therapeutic maximum concentration in plasma (Cmax), were expressed as the fold of that particular effect with respect to their Cmax. The following tests were used at 37°C: hERG (human ether-à-go-go-related gene) blockade and trafficking, rabbit heart ventricular preparations, and sodium and slow potassium ion current interference (INa and IKs, respectively). Chloroquine, halofantrine, mefloquine, and lumefantrine were tested in the hERG studies, but only chloroquine, dofetilide, lumefantrine, and the combination of artemether-lumefantrine were used in the rabbit heart ventricular preparations, hERG trafficking studies, and INa and IKs analyses. A proper reference was used in each test. In hERG studies, the high 50% inhibitory concentration (IC50) of halofantrine, which was lower than its Cmax, was confirmed. All the other compounds blocked hERG, with IC50s ranging from 3- to 30-fold their Cmaxs. In hERG trafficking studies, the facilitative effects of chloroquine at about 30-fold its Cmax were confirmed and DHA blocked it at a concentration about 300-fold its Cmax. In rabbit heart ventricular preparations, dofetilide, used as a positive control, revealed a high risk of torsades de pointes, whereas chloroquine showed a medium risk. Neither DHA-PQP nor artemether-lumefantrine displayed an in vitro signal for a significant proarrhythmic risk. Only chloroquine blocked the INa ion current and did so at about 30-fold its Cmax. No effect on IKs was detected. In conclusion, despite significant hERG blockade, DHA-PQP and artemether-lumefantrine do not appear to induce potential torsadogenic effects in vitro, affect hERG trafficking, or block sodium and slow potassium ion currents. PMID:22391528

  2. Characterization of the potent in vitro and in vivo antimalarial activities of ionophore compounds.

    PubMed Central

    Gumila, C; Ancelin, M L; Delort, A M; Jeminet, G; Vial, H J

    1997-01-01

    Large-scale in vitro screening of different types of ionophores previously pinpointed nine compounds that were very active and selective in vitro against Plasmodium falciparum; their in vitro and in vivo antimalarial effects were further studied. Addition of the ionophores to synchronized P. falciparum suspensions revealed that all P. falciparum stages were sensitive to the drugs. However, the schizont stages were three- to ninefold more sensitive, and 12 h was required for complete parasite clearance. Pretreatment of healthy erythrocytes with toxic doses of ionophores for 24 to 48 h showed that the activity was not due to an irreversible effect on the host erythrocyte. No preferential ionophore adsorption in infected or uninfected erythrocytes occurred. On the other hand, ionophore molecules strongly bound to serum proteins since increasing the serum concentration from 2 to 50% led to almost a 25-fold parallel increase in the ionophore 50% inhibitory concentration. Mice infected with the malaria parasites Plasmodium vinckei petteri or Plasmodium chabaudi were successfully treated with eight ionophores in a 4-day suppressive test. The 50% effective dose after intraperitoneal administration ranged from 0.4 to 4.1 mg/kg of body weight, and the therapeutic indices were about 5 for all ionophores except monensin A methyl ether, 5-bromo lasalocid A, and gramicidin D, whose therapeutic indices were 12, 18, and 344, respectively. These three compounds were found to be curative, with no recrudescence. Gramicidin D, which presented impressive antimalarial activity, requires parenteral administration, while 5-bromo lasalocid A has the major advantage of being active after oral administration. Overall, the acceptable levels of toxicity and the good in vivo therapeutic indices in the rodent model highlight the interesting potential of these ionophores for the treatment of malaria in higher animals. PMID:9055986

  3. Effects of an antimalarial quinazoline derivative on human erythrocytes and on cell membrane molecular models.

    PubMed

    Rojas-Aguirre, Yareli; Hernández-Luis, Francisco; Mendoza-Martínez, César; Sotomayor, Carlos Patricio; Aguilar, Luis Felipe; Villena, Fernando; Castillo, Ivan; Hernández, David J; Suwalsky, Mario

    2012-03-01

    Plasmodium, the parasite which causes malaria in humans multiplies in the liver and then infects circulating erythrocytes. Thus, the role of the erythrocyte cell membrane in antimalarial drug activity and resistance has key importance. The effects of the antiplasmodial N(6)-(4-methoxybenzyl)quinazoline-2,4,6-triamine (M4), and its inclusion complex (M4/HPβCD) with 2-hydroxypropyl-β-cyclodextrin (HPβCD) on human erythrocytes and on cell membrane molecular models are herein reported. This work evidences that M4/HPβCD interacts with red cells as follows: a) in scanning electron microscopy (SEM) studies on human erythrocytes induced shape changes at a 10μM concentration; b) in isolated unsealed human erythrocyte membranes (IUM) a concentration as low as 1μM induced sharp DPH fluorescence anisotropy decrease whereas increasing concentrations produced a monotonically decrease of DPH fluorescence lifetime at 37°C; c) X-ray diffraction studies showed that 200μM induced a complete structural perturbation of dimyristoylphosphatidylcholine (DMPC) bilayers whereas no significant effects were detected in dimyristoylphosphatidylethanolamine (DMPE) bilayers, classes of lipids present in the outer and inner monolayers of the human erythrocyte membrane, respectively; d) fluorescence spectroscopy data showed that increasing concentrations of the complex interacted with the deep hydrophobic core of DMPC large unilamellar vesicles (LUV) at 18°C. All these experiments are consistent with the insertion of M4/HPβCD in the outer monolayer of the human erythrocyte membrane; thus, it can be considered a promising and novel antimalarial agent.

  4. Presumptive Treatment of Malaria from Formal and Informal Drug Vendors in Nigeria

    PubMed Central

    Isiguzo, Chinwoke; Anyanti, Jennifer; Ujuju, Chinazo; Nwokolo, Ernest; De La Cruz, Anna; Schatzkin, Eric; Modrek, Sepideh; Montagu, Dominic; Liu, Jenny

    2014-01-01

    Background Despite policies that recommend parasitological testing before treatment for malaria, presumptive treatment remains widespread in Nigeria. The majority of Nigerians obtain antimalarial drugs from two types of for-profit drug vendors—formal and informal medicine shops—but little is known about the quality of malaria care services provided at these shops. Aims This study seeks to (1) describe the profile of patients who seek treatment at different types of drug outlets, (2) document the types of drugs purchased for treating malaria, (3) assess which patients are purchasing recommended drugs, and (4) estimate the extent of malaria over-treatment. Methods In urban, peri-urban, and rural areas in Oyo State, customers exiting proprietary and patent medicine vendor (PPMV) shops or pharmacies having purchased anti-malarial drugs were surveyed and tested with malaria rapid diagnostic test. A follow-up phone survey was conducted four days after to assess self-reported drug administration. Bivariate and multivariate regression analysis was conducted to determine the correlates of patronizing a PPMV versus pharmacy, and the likelihood of purchasing an artemisinin-combination therapy (ACT) drug. Results Of the 457participants who sought malaria treatment in 49 enrolled outlets, nearly 92% had diagnosed their condition by themselves, a family member, or a friend. Nearly 60% pharmacy customers purchased an ACT compared to only 29% of PPMV customers, and pharmacy customers paid significantly more on average. Multivariate regression results show that patrons of PPMVs were younger, less wealthy, waited fewer days before seeking care, and were less likely to be diagnosed at a hospital, clinic, or laboratory. Only 3.9% of participants tested positive with a malaria rapid diagnostic test. Conclusions Poorer individuals seeking care at PPMVs are more likely to receive inappropriate malaria treatment when compared to those who go to pharmacies. Increasing accessibility to

  5. Development and Optimization of a Novel 384-Well Anti-Malarial Imaging Assay Validated for High-Throughput Screening

    PubMed Central

    Duffy, Sandra; Avery, Vicky M.

    2012-01-01

    With the increasing occurrence of drug resistance in the malaria parasite, Plasmodium falciparum, there is a great need for new and novel anti-malarial drugs. We have developed a 384-well, high-throughput imaging assay for the detection of new anti-malarial compounds, which was initially validated by screening a marine natural product library, and subsequently used to screen more than 3 million data points from a variety of compound sources. Founded on another fluorescence-based P. falciparum growth inhibition assay, the DNA-intercalating dye 4′,6-diamidino-2-phenylindole, was used to monitor changes in parasite number. Fluorescent images were acquired on the PerkinElmer Opera High Throughput confocal imaging system and analyzed with a spot detection algorithm using the Acapella data processing software. Further optimization of this assay sought to increase throughput, assay stability, and compatibility with our high-throughput screening equipment platforms. The assay typically yielded Z'-factor values of 0.5–0.6, with signal-to-noise ratios of 12. PMID:22232455

  6. KAF156 is an antimalarial clinical candidate with potential for use in prophylaxis, treatment, and prevention of disease transmission.

    PubMed

    Kuhen, Kelli L; Chatterjee, Arnab K; Rottmann, Matthias; Gagaring, Kerstin; Borboa, Rachel; Buenviaje, Jennifer; Chen, Zhong; Francek, Carolyn; Wu, Tao; Nagle, Advait; Barnes, S Whitney; Plouffe, David; Lee, Marcus C S; Fidock, David A; Graumans, Wouter; van de Vegte-Bolmer, Marga; van Gemert, Geert J; Wirjanata, Grennady; Sebayang, Boni; Marfurt, Jutta; Russell, Bruce; Suwanarusk, Rossarin; Price, Ric N; Nosten, Francois; Tungtaeng, Anchalee; Gettayacamin, Montip; Sattabongkot, Jetsumon; Taylor, Jennifer; Walker, John R; Tully, David; Patra, Kailash P; Flannery, Erika L; Vinetz, Joseph M; Renia, Laurent; Sauerwein, Robert W; Winzeler, Elizabeth A; Glynne, Richard J; Diagana, Thierry T

    2014-09-01

    Renewed global efforts toward malaria eradication have highlighted the need for novel antimalarial agents with activity against multiple stages of the parasite life cycle. We have previously reported the discovery of a novel class of antimalarial compounds in the imidazolopiperazine series that have activity in the prevention and treatment of blood stage infection in a mouse model of malaria. Consistent with the previously reported activity profile of this series, the clinical candidate KAF156 shows blood schizonticidal activity with 50% inhibitory concentrations of 6 to 17.4 nM against P. falciparum drug-sensitive and drug-resistant strains, as well as potent therapeutic activity in a mouse models of malaria with 50, 90, and 99% effective doses of 0.6, 0.9, and 1.4 mg/kg, respectively. When administered prophylactically in a sporozoite challenge mouse model, KAF156 is completely protective as a single oral dose of 10 mg/kg. Finally, KAF156 displays potent Plasmodium transmission blocking activities both in vitro and in vivo. Collectively, our data suggest that KAF156, currently under evaluation in clinical trials, has the potential to treat, prevent, and block the transmission of malaria.

  7. When Quality Beats Quantity: Decision Theory, Drug Discovery, and the Reproducibility Crisis.

    PubMed

    Scannell, Jack W; Bosley, Jim

    2016-01-01

    A striking contrast runs through the last 60 years of biopharmaceutical discovery, research, and development. Huge scientific and technological gains should have increased the quality of academic science and raised industrial R&D efficiency. However, academia faces a "reproducibility crisis"; inflation-adjusted industrial R&D costs per novel drug increased nearly 100 fold between 1950 and 2010; and drugs are more likely to fail in clinical development today than in the 1970s. The contrast is explicable only if powerful headwinds reversed the gains and/or if many "gains" have proved illusory. However, discussions of reproducibility and R&D productivity rarely address this point explicitly. The main objectives of the primary research in this paper are: (a) to provide quantitatively and historically plausible explanations of the contrast; and (b) identify factors to which R&D efficiency is sensitive. We present a quantitative decision-theoretic model of the R&D process. The model represents therapeutic candidates (e.g., putative drug targets, molecules in a screening library, etc.) within a "measurement space", with candidates' positions determined by their performance on a variety of assays (e.g., binding affinity, toxicity, in vivo efficacy, etc.) whose results correlate to a greater or lesser degree. We apply decision rules to segment the space, and assess the probability of correct R&D decisions. We find that when searching for rare positives (e.g., candidates that will successfully complete clinical development), changes in the predictive validity of screening and disease models that many people working in drug discovery would regard as small and/or unknowable (i.e., an 0.1 absolute change in correlation coefficient between model output and clinical outcomes in man) can offset large (e.g., 10 fold, even 100 fold) changes in models' brute-force efficiency. We also show how validity and reproducibility correlate across a population of simulated screening and

  8. When Quality Beats Quantity: Decision Theory, Drug Discovery, and the Reproducibility Crisis

    PubMed Central

    Scannell, Jack W.; Bosley, Jim

    2016-01-01

    A striking contrast runs through the last 60 years of biopharmaceutical discovery, research, and development. Huge scientific and technological gains should have increased the quality of academic science and raised industrial R&D efficiency. However, academia faces a "reproducibility crisis"; inflation-adjusted industrial R&D costs per novel drug increased nearly 100 fold between 1950 and 2010; and drugs are more likely to fail in clinical development today than in the 1970s. The contrast is explicable only if powerful headwinds reversed the gains and/or if many "gains" have proved illusory. However, discussions of reproducibility and R&D productivity rarely address this point explicitly. The main objectives of the primary research in this paper are: (a) to provide quantitatively and historically plausible explanations of the contrast; and (b) identify factors to which R&D efficiency is sensitive. We present a quantitative decision-theoretic model of the R&D process. The model represents therapeutic candidates (e.g., putative drug targets, molecules in a screening library, etc.) within a “measurement space", with candidates' positions determined by their performance on a variety of assays (e.g., binding affinity, toxicity, in vivo efficacy, etc.) whose results correlate to a greater or lesser degree. We apply decision rules to segment the space, and assess the probability of correct R&D decisions. We find that when searching for rare positives (e.g., candidates that will successfully complete clinical development), changes in the predictive validity of screening and disease models that many people working in drug discovery would regard as small and/or unknowable (i.e., an 0.1 absolute change in correlation coefficient between model output and clinical outcomes in man) can offset large (e.g., 10 fold, even 100 fold) changes in models’ brute-force efficiency. We also show how validity and reproducibility correlate across a population of simulated screening and

  9. The potential of anti-malarial compounds derived from African medicinal plants, part I: a pharmacological evaluation of alkaloids and terpenoids

    PubMed Central

    2013-01-01

    Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from “very active” to “weakly active”. However, only the compounds which showed anti-malarial activities from “very active” to “moderately active” are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria. PMID:24330395

  10. Comparison of the Exposure Time Dependence of the Activities of Synthetic Ozonide Antimalarials and Dihydroartemisinin against K13 Wild-Type and Mutant Plasmodium falciparum Strains.

    PubMed

    Yang, Tuo; Xie, Stanley C; Cao, Pengxing; Giannangelo, Carlo; McCaw, James; Creek, Darren J; Charman, Susan A; Klonis, Nectarios; Tilley, Leann

    2016-08-01

    Fully synthetic endoperoxide antimalarials, namely, OZ277 (RBx11160; also known as arterolane) and OZ439 (artefenomel), have been approved for marketing or are currently in clinical development. We undertook an analysis of the kinetics of the in vitro responses of Plasmodium falciparum to the new ozonide antimalarials. For these studies we used a K13 mutant (artemisinin resistant) isolate from a region in Cambodia and a genetically matched (artemisinin sensitive) K13 revertant. We used a pulsed-exposure assay format to interrogate the time dependence of the response. Because the ozonides have physicochemical properties different from those of the artemisinins, assay optimization was required to ensure that the drugs were completely removed following the pulsed exposure. Like that of artemisinins, ozonide activity requires active hemoglobin degradation. Short pulses of the ozonides were less effective than short pulses of dihydroartemisinin; however, when early-ring-stage parasites were exposed to drugs for periods relevant to their in vivo exposure, the ozonide antimalarials were markedly more effective. PMID:27161632

  11. Comparison of the Exposure Time Dependence of the Activities of Synthetic Ozonide Antimalarials and Dihydroartemisinin against K13 Wild-Type and Mutant Plasmodium falciparum Strains

    PubMed Central

    Yang, Tuo; Xie, Stanley C.; Cao, Pengxing; Giannangelo, Carlo; McCaw, James; Creek, Darren J.; Charman, Susan A.; Klonis, Nectarios

    2016-01-01

    Fully synthetic endoperoxide antimalarials, namely, OZ277 (RBx11160; also known as arterolane) and OZ439 (artefenomel), have been approved for marketing or are currently in clinical development. We undertook an analysis of the kinetics of the in vitro responses of Plasmodium falciparum to the new ozonide antimalarials. For these studies we used a K13 mutant (artemisinin resistant) isolate from a region in Cambodia and a genetically matched (artemisinin sensitive) K13 revertant. We used a pulsed-exposure assay format to interrogate the time dependence of the response. Because the ozonides have physicochemical properties different from those of the artemisinins, assay optimization was required to ensure that the drugs were completely removed following the pulsed exposure. Like that of artemisinins, ozonide activity requires active hemoglobin degradation. Short pulses of the ozonides were less effective than short pulses of dihydroartemisinin; however, when early-ring-stage parasites were exposed to drugs for periods relevant to their in vivo exposure, the ozonide antimalarials were markedly more effective. PMID:27161632

  12. Antimalarial activity of Bidens pilosa L. (Asteraceae) ethanol extracts from wild plants collected in various localities or plants cultivated in humus soil.

    PubMed

    Andrade-Neto, Valter F; Brandão, Maria G L; Oliveira, Francielda Q; Casali, Vicente W D; Njaine, Brian; Zalis, Mariano G; Oliveira, Luciana A; Krettli, Antoniana U

    2004-08-01

    Bidens pilosa (Asteraceae), a medicinal plant used worldwide, has antimalarial activity as shown in previous work. This study tested ethanol extracts from wild plants collected in three different regions of Brazil and from plants cultivated in various soil conditions. The extracts were active in mice infected with P. berghei: doses of < or =500 mg/kg administered by oral route reduced malaria parasitaemia and mouse mortality; higher doses were found to be less effective. Tested in vitro against three P. falciparum isolates, two chloroquine resistant and one mefloquine resistant, the plants cultivated under standard conditions, and in humus enriched soil, were active; but the wild plants were the most active. Analysis using thin layer chromatography demonstrated the presence of flavonoids (compounds considered responsible for the antimalarial activity) in all plants tested, even though at different profiles. Because B. pilosa is proven to be active against P. falciparum drug-resistant parasites in vitro, and in rodent malaria in vivo, it is a good candidate for pre-clinical tests as a phytotherapeutic agent or for chemical isolation of the active compounds with the aim of finding new antimalarial drugs.

  13. Albumin-bound nanoparticles of practically water-insoluble antimalarial lead greatly enhance its efficacy.

    PubMed

    Ibrahim, Nehal; Ibrahim, Hany; Dormoi, Jerome; Briolant, Sébastien; Pradines, Bruno; Moreno, Alicia; Mazier, Dominique; Legrand, Philippe; Nepveu, Françoise

    2014-04-10

    We recently showed that the indolone-N-oxides can be promising candidates for the treatment of chloroquine-resistant malaria. However, the in vivo assays have been hampered by the very poor aqueous solubility of these compounds resulting in poor and variable activity. Here, we describe the preparation, characterization and in vivo evaluation of biodegradable albumin-bound indolone-N-oxide nanoparticles. Nanoparticles were prepared by precipitation followed by high-pressure homogenization and characterized by photon correlation spectroscopy, transmission electron microscopy, differential scanning calorimetry and X-ray powder diffraction. The process was optimized to yield nanoparticles of controllable diameter with narrow size distribution suitable for intravenous administration, which guarantees direct drug contact with parasitized erythrocytes. Stable nanoparticles showed greatly enhanced dissolution rate (complete drug release within 30 min compared to 1.5% of pure drug) preserving the rapid antimalarial activity. The formulation achieved complete cure of Plasmodium berghei-infected mice at 25mg/kg with parasitemia inhibition (99.1%) comparable to that of artesunate and chloroquine and was remarkably more effective in prolonging survival time and inhibiting recrudescence. In 'humanized' mice infected with Plasmodium falciparum, the same dose proved to be highly effective: with parasitemia reduced by 97.5% and the mean survival time prolonged. This formulation can help advance the preclinical trials of indolone-N-oxides. Albumin-bound nanoparticles represent a new strategic approach to use this most abundant plasma protein to target malaria-infected erythrocytes.

  14. Antimalarial 4(1H)-pyridones bind to the Qi site of cytochrome bc1

    PubMed Central

    Capper, Michael J.; O’Neill, Paul M.; Fisher, Nicholas; Strange, Richard W.; Moss, Darren; Ward, Stephen A.; Berry, Neil G.; Lawrenson, Alexandre S.; Hasnain, S. Samar; Biagini, Giancarlo A.; Antonyuk, Svetlana V.

    2015-01-01

    Cytochrome bc1 is a proven drug target in the prevention and treatment of malaria. The rise in drug-resistant strains of Plasmodium falciparum, the organism responsible for malaria, has generated a global effort in designing new classes of drugs. Much of the design/redesign work on overcoming this resistance has been focused on compounds that are presumed to bind the Qo site (one of two potential binding sites within cytochrome bc1) using the known crystal structure of this large membrane-bound macromolecular complex via in silico modeling. Cocrystallization of the cytochrome bc1 complex with the 4(1H)-pyridone class of inhibitors, GSK932121 and GW844520, that have been shown to be potent antimalarial agents in vivo, revealed that these inhibitors do not bind at the Qo site but bind at the Qi site. The discovery that these compounds bind at the Qi site may provide a molecular explanation for the cardiotoxicity and eventual failure of GSK932121 in phase-1 clinical trial and highlight the need for direct experimental observation of a compound bound to a target site before chemical optimization and development for clinical trials. The binding of the 4(1H)-pyridone class of inhibitors to Qi also explains the ability of this class to overcome parasite Qo-based atovaquone resistance and provides critical structural information for future design of new selective compounds with improved safety profiles. PMID:25564664

  15. Antimalarial Iron Chelator FBS0701 Blocks Transmission by Plasmodium falciparum Gametocyte Activation Inhibition

    PubMed Central

    Ferrer, Patricia; Vega-Rodriguez, Joel; Tripathi, Abhai K.; Jacobs-Lorena, Marcelo

    2014-01-01

    Reducing the transmission of the malarial parasite by Anopheles mosquitoes using drugs or vaccines remains a main focus in the efforts to control malaria. Iron chelators have been studied as potential antimalarial drugs due to their activities against different stages of the parasite. The iron chelator FBS0701 affects the development of Plasmodium falciparum early gametocytes and lowers blood-stage parasitemia. Here, we tested the effect of FBS0701 on stage V gametocyte infectivity for mosquitoes. The incubation of stage V gametocytes for up to 3 days with increasing concentrations of FBS0701 resulted in a significant dose-related reduction in mosquito infectivity, as measured by the numbers of oocysts per mosquito. The reduction in mosquito infectivity was due to the inhibition of male and female gametocyte activation. The preincubation of FBS0701 with ferric chloride restored gametocyte infectivity, showing that the inhibitory effect of FBS0701 was quenched by iron. Deferoxamine, another iron chelator, also reduced gametocyte infectivity but to a lesser extent. Finally, the simultaneous administration of drug and gametocytes to mosquitoes without previous incubation did not significantly reduce the numbers of oocysts. These results show the importance of gametocyte iron metabolism as a potential target for new transmission-blocking strategies. PMID:25512427

  16. Development of polymeric nanoparticles with highly entrapped herbal hydrophilic drug using nanoprecipitation technique: an approach of quality by design.

    PubMed

    Vuddanda, Parameswara Rao; Mishra, Amit; Singh, Sanjay Kumar; Singh, Sanjay

    2015-01-01

    The intention of this study is to achieve higher entrapment efficiency (EE) of berberine chloride (selected hydrophilic drug) using nanoprecipitation technique. The solubility of drug was studied in various pH buffers (1.2-7.2) for selection of aqueous phase and stabilizer. Quality by design (QbD)-based 3(2) factorial design were employed for optimization of formulation variables; drug to polymer ratio (X1) and surfactant concentration (X2) on entrapment efficiency (EE), particle size (PS) and polydispersity index (PDI) of the nanoparticles. The nanoparticles were subjected to solid state analysis, in vitro drug release and stability study. The aqueous phase and stabilizer selected for the formulations were pH 4.5 phthalate buffer and surfactant F-68, respectively. The formulation (F-6) containing drug to polymer ratio (1:3) and stabilizer (F-68) concentration of 50 mM exhibited best EE (82.12%), PS (196.71 nm), PDI (0.153). The various solid state characterizations assured that entrapped drug is amorphous and nanoparticles are fairly spherical in shape. In vitro drug release of the F-6 exhibited sustained release with non-Fickian diffusion and stable at storage condition. This work illustrates that the proper selection of aqueous phase and optimization of formulation variables could be helpful in improving the EE of hydrophilic drugs by nanoprecipitation technique.

  17. An Exploration of Quality of Life and Its Predictors in Patients with Addictive Disorders: Gambling, Alcohol and Drugs

    ERIC Educational Resources Information Center

    Manning, Victoria; Gomez, Brenda; Guo, Song; Low, Yee Deng; Koh, Puay Kee; Wong, Kim Eng

    2012-01-01

    The study set out to examine Quality of Life (QoL), specifically subjective well being in three different addiction populations (260 alcohol-dependent, 282 drug-dependent, and 132 pathological gambling outpatients) at their first visit to treatment, using the Personal Well being Index (PWI). The mean PWI score for all patients was significantly…

  18. In vivo antimalarial activity of extracts of Tanzanian medicinal plants used for the treatment of malaria

    PubMed Central

    Nondo, Ramadhani S.O.; Erasto, Paul; Moshi, Mainen J.; Zacharia, Abdallah; Masimba, Pax J.; Kidukuli, Abdul W.

    2016-01-01

    Plants used in traditional medicine have been the source of a number of currently used antimalarial medicines and continue to be a promising resource for the discovery of new classes of antimalarial compounds. The aim of this study was to evaluate in vivo antimalarial activity of four plants; Erythrina schliebenii Harms, Holarrhena pubescens Buch-Ham, Phyllanthus nummulariifolius Poir, and Caesalpinia bonducella (L.) Flem used for treatment of malaria in Tanzania. In vivo antimalarial activity was assessed using the 4-day suppressive antimalarial assay. Mice were infected by injection via tail vein with 2 × 107 erythrocytes infected with Plasmodium berghei ANKA. Extracts were administered orally, once daily, for a total of four daily doses from the day of infection. Chloroquine (10 mg/kg/day) and solvent (5 mL/kg/day) were used as positive and negative controls, respectively. The extracts of C. bonducella, E. schliebenii, H. pubescens, and P. nummulariifolius exhibited dose-dependent suppression of parasite growth in vivo in mice, with the highest suppression being by C. bonducella extract. While each of the plant extracts has potential to yield useful antimalarial compounds, the dichloromethane root extract of C. bonducella seems to be the most promising for isolation of active antimalarial compound(s). In vivo antimalarial activity presented in this study supports traditional uses of C. bonducella roots, E. schliebenii stem barks, H. pubescens roots, and P. nummulariifolius for treatment of malaria. PMID:27144154

  19. Novel in vivo active anti-malarials based on a hydroxy-ethyl-amine scaffold.

    PubMed

    Ciana, Claire-Lise; Siegrist, Romain; Aissaoui, Hamed; Marx, Léo; Racine, Sophie; Meyer, Solange; Binkert, Christoph; de Kanter, Ruben; Fischli, Christoph; Wittlin, Sergio; Boss, Christoph

    2013-02-01

    A novel series of anti-malarials, based on a hydroxy-ethyl-amine scaffold, initially identified as peptidomimetic protease inhibitors is described. Combination of the hydroxy-ethyl-amine anti-malarial phramacophore with the known Mannich base pharmacophore of amodiaquine (57) resulted in promising in vivo active novel derivatives. PMID:23260352

  20. Characterization of Novel Antimalarial Compound ACT-451840: Preclinical Assessment of Activity and Dose–Efficacy Modeling

    PubMed Central

    Le Bihan, Amélie; Angulo-Barturen, Iñigo; Binkert, Christoph; Boss, Christoph; Brun, Reto; Brunner, Ralf; Buchmann, Stephan; Dechering, Koen J.; Delves, Michael; Ewerling, Sonja; Ferrer, Santiago; Fischli, Christoph; Gamo–Benito, Francisco Javier; Heidmann, Bibia; Jiménez-Díaz, María Belén; Leroy, Didier; Martínez, Maria Santos; Meyer, Solange; Moehrle, Joerg J.; Noviyanti, Rintis; Sanz, Laura María; Sauerwein, Robert W.; Scheurer, Christian; Schleiferboeck, Sarah; Sinden, Robert; Snyder, Christopher; Straimer, Judith; Wirjanata, Grennady; Marfurt, Jutta; Weller, Thomas; Clozel, Martine; Wittlin, Sergio

    2016-01-01

    Background Artemisinin resistance observed in Southeast Asia threatens the continued use of artemisinin-based combination therapy in endemic countries. Additionally, the diversity of chemical mode of action in the global portfolio of marketed antimalarials is extremely limited. Addressing the urgent need for the development of new antimalarials, a chemical class of potent antimalarial compounds with a novel mode of action was recently identified. Herein, the preclinical characterization of one of these compounds, ACT-451840, conducted in partnership with academic and industrial groups is presented. Method and Findings The properties of ACT-451840 are described, including its spectrum of activities against multiple life cycle stages of the human malaria parasite Plasmodium falciparum (asexual and sexual) and Plasmodium vivax (asexual) as well as oral in vivo efficacies in two murine malaria models that permit infection with the human and the rodent parasites P. falciparum and Plasmodium berghei, respectively. In vitro, ACT-451840 showed a 50% inhibition concentration of 0.4 nM (standard deviation [SD]: ± 0.0 nM) against the drug-sensitive P. falciparum NF54 strain. The 90% effective doses in the in vivo efficacy models were 3.7 mg/kg against P. falciparum (95% confidence interval: 3.3–4.9 mg/kg) and 13 mg/kg against P. berghei (95% confidence interval: 11–16 mg/kg). ACT-451840 potently prevented male gamete formation from the gametocyte stage with a 50% inhibition concentration of 5.89 nM (SD: ± 1.80 nM) and dose-dependently blocked oocyst development in the mosquito with a 50% inhibitory concentration of 30 nM (range: 23–39). The compound’s preclinical safety profile is presented and is in line with the published results of the first-in-man study in healthy male participants, in whom ACT-451840 was well tolerated. Pharmacokinetic/pharmacodynamic (PK/PD) modeling was applied using efficacy in the murine models (defined either as antimalarial activity or as

  1. A rapid HPLC procedure for analysis of analgesic pharmaceutical mixtures for quality assurance and drug diversion testing.

    PubMed

    Wolf, Carl E; Poklis, Alphonse

    2005-10-01

    A simple high-performance liquid chromatographic (HPLC) method that allows for the rapid identification and quantification of analgesic and anesthetic solutions typically used in surgical procedures or patient controlled analgesia is presented. The separation of bupivacaine, clonidine, fentanyl, hydromorphone, midazolam, and morphine is complete in less than 20 min. The method allows test solutions to be either directly injected or diluted prior to injection into the HPLC system. The method is useful from the standpoint that pharmaceutical preparations are usually submitted with the known drug of interest and expected concentration. The method is also useful for initial screening of solutions submitted that are either unknown or of questionable identity. The method has been successfully applied as part of hospital-based quality control and quality assurance programs to detect not only errors in the preparation of solutions of scheduled drugs, but also to uncover illegal diversion of drugs of abuse by medical personnel.

  2. Drug treatment of Alzheimer's disease. Effects on caregiver burden and patient quality of life.

    PubMed

    Hollister, L; Gruber, N

    1996-01-01

    Alzheimer's disease is a devastating illness that will become more common as the population ages. Although clinical diagnosis of the illness is not certain without histological examination of the brain, and misdiagnosis may occur, broad working criteria to help diagnose the likely presence of Alzheimer's disease are available. Thoughtful clinical evaluation improves diagnostic accuracy, and appropriately diagnosed patients are critical for involvement in research into new antidementia agents. Essential to the discovery of new drugs is careful measurement of illness response. A variety of scales--some aimed at patients, others at their caregivers, and yet others for clinicians--assess Alzheimer's disease severity, progression, symptom response, and quality of life. Of note, patient response is not the only measurement of treatment benefit today. Growing interest is also being placed on tracking the possible amelioration of caregiver 'burden'. This burden refers to the psychological, physical, and material costs of providing care for an Alzheimer's patient over long periods of time. A number of scales and questionnaires have been developed and are occasionally used. Many drugs have been tried in Alzheimer's disease, but very few have produced any benefit, and this is often modest. Ergoloid mesylates, initially thought to be effective, are now considered of little value. The cholinomimetic drugs, especially the acetylcholinesterase inhibitor tacrine, have provided a very modest benefit, slowing the progression of the illness for a number of months. No cognitive improvement has been noted with the various nootropic agents such as piracetam. Early studies with levacecarnine (acetyl-L-carnitine), a substance that facilitates the use of fatty acids, memantidine, the dimethyl derivative of amantidine, and the calcium channel blocker nimodipine, have shown some promise, but require larger, more rigorous studies. As mentioned above, documenting effects in individual patients

  3. Quality of life, depression, anxiety and suicidal ideation among men who inject drugs in Delhi, India

    PubMed Central

    2013-01-01

    Background Mental disorders such as depression, anxiety and suicide represent an important public health problem in India. Elsewhere in the world a high prevalence of symptoms of common mental disorders have been found among people who inject drugs (PWID). Research in India has largely overlooked symptoms of common mental disorders among this high risk group. This paper reports on the results of a survey examining quality of life, depression, anxiety and suicidal ideation among adult males who inject drugs living in Delhi. Methods Participants (n = 420) were recruited from needle and syringe programs using time location sampling and were interviewed using an interviewer-administered questionnaire. Self-report symptom scales were used to measure the severity of symptoms of depression (PHQ-9) and anxiety (GAD-2) within the preceding 2 weeks. We assessed the presence of suicidal thoughts and attempts within the past 12 months. Results The mean length of injecting career was 20.9 years indicating a sample of chronic injecting drug users, of whom only one-third (38%) were born in Delhi. The level of illiteracy was very high (62%), and just 2% had completed class 12. Scavenging / rag picking was the main form of income for 48%, and many were homeless (69%). One-third (33%) had been beaten up at least twice during the preceding 6 months, and many either never (45%) or rarely (27%) attended family events. We found a high prevalence of depressive (84%, cut-off ≥10) and anxiety (71%, cut-off score of ≥3) symptoms. Fifty-three percent thought about killing themselves in the past 12 months, and 36% had attempted to kill themselves. Conclusions Our findings revealed a socially excluded population of PWID in Delhi who have minimal education and are often homeless, leaving them vulnerable to physical violence, poverty, poor health, imprisonment and disconnection from family. The high prevalence of psychological distress found in this study has implications for

  4. A retrospective analysis of the change in anti-malarial treatment policy: Peru

    PubMed Central

    Williams, Holly Ann; Vincent-Mark, Arlene; Herrera, Yenni; Chang, O Jaime

    2009-01-01

    Background National malaria control programmes must deal with the complex process of changing national malaria treatment guidelines, often without guidance on the process of change. Selecting a replacement drug is only one issue in this process. There is a paucity of literature describing successful malaria treatment policy changes to help guide control programs through this process. Objectives To understand the wider context in which national malaria treatment guidelines were formulated in a specific country (Peru). Methods Using qualitative methods (individual and focus group interviews, stakeholder analysis and a review of documents), a retrospective analysis of the process of change in Peru's anti-malarial treatment policy from the early 1990's to 2003 was completed. Results The decision to change Peru's policies resulted from increasing levels of anti-malarial drug resistance, as well as complaints from providers that the drugs were no longer working. The context of the change occurred in a time in which Peru was changing national governments, which created extreme challenges in moving the change process forward. Peru utilized a number of key strategies successfully to ensure that policy change would occur. This included a) having the process directed by a group who shared a common interest in malaria and who had long-established social and professional networks among themselves, b) engaging in collaborative teamwork among nationals and between nationals and international collaborators, c) respect for and inclusion of district-level staff in all phases of the process, d) reliance on high levels of technical and scientific knowledge, e) use of standardized protocols to collect data, and f) transparency. Conclusion Although not perfectly or fully implemented by 2003, the change in malaria treatment policy in Peru occurred very quickly, as compared to other countries. They identified a problem, collected the data necessary to justify the change, utilized

  5. Cardiac Valve Noise Reduction by Non-Drug Interventions Improves the Sleep Quality of Patients after Mechanical Cardiac Valve Implantation

    PubMed Central

    Xu, Le; Huang, Xizhen; Jiang, Fei; Lin, Fen; Ye, Qingyang; Lin, Jianling

    2016-01-01

    Purpose: To investigate the effects of non-drug interventions on the sleep quality of patients after mechanical cardiac valve implantation. Methods: In this prospective, randomized, controlled trial, 64 patients scheduled for mechanical mitral valve replacement were recruited. Patients underwent cognitive behavioral therapy and wore noise cancelling earplugs and eye mask. Sleep quality was evaluated on the 4th after admission and the 5th days after operation. The primary outcome was the total sleep quality score differences between the 4th day after admission and the 5th day after operation. Results: All patients had been suffering from poor sleep quality for a month before admission. There was no difference between both groups on the 4th day after admission. Overall sleep quality in the intervention group was better than in the control group on the 5th day after operation. The subjective sleep quality of the patients in each group was significantly lower on the 5th day after the operation than on the 4th day after admission (P <0.05). Conclusion: Non-drug intervention could improve the sleep quality of patients after mechanical cardiac valve implantation and help the postoperative recovery of the patients. (Trial registration: ChiCTR-TRC-14004405, 21 March 2014.) PMID:26853244

  6. Cytotoxic and antimalarial bisbenzylisoquinoline alkaloids from Stephania erecta.

    PubMed

    Likhitwitayawuid, K; Angerhofer, C K; Cordell, G A; Pezzuto, J M; Ruangrungsi, N

    1993-01-01

    (+)-2-N-Methyltelobine [1], a new alkaloid, together with twelve known bisbenzylisoquinolines, was isolated from the tubers of Stephania erecta. The structure determination and the complete 1H- and unambiguous 13C-nmr assignments of 1 were obtained through extensive use of several 1D and 2D nmr techniques. All alkaloids inhibited the growth of cultured Plasmodium falciparum strains D-6 and W-2 and displayed nonselective cytotoxicity with a battery of cultured mammalian cells. These data were used for the calculation of selectivity indices. Relative to known antimalarial agents, these bisbenzylisoquinoline alkaloids do not appear to be promising clinical candidates at the present time. PMID:8450319

  7. Got ACTs? Availability, price, market share and provider knowledge of anti-malarial medicines in public and private sector outlets in six malaria-endemic countries

    PubMed Central

    2011-01-01

    Background Artemisinin-based combination therapy (ACT) is the first-line malaria treatment throughout most of the malaria-endemic world. Data on ACT availability, price and market share are needed to provide a firm evidence base from which to assess the current situation concerning quality-assured ACT supply. This paper presents supply side data from ACTwatch outlet surveys in Benin, the Democratic Republic of Congo (DRC), Madagascar, Nigeria, Uganda and Zambia. Methods Between March 2009 and June 2010, nationally representative surveys of outlets providing anti-malarials to consumers were conducted. A census of all outlets with the potential to provide anti-malarials was conducted in clusters sampled randomly. Results 28,263 outlets were censused, 51,158 anti-malarials were audited, and 9,118 providers interviewed. The proportion of public health facilities with at least one first-line quality-assured ACT in stock ranged between 43% and 85%. Among private sector outlets stocking at least one anti-malarial, non-artemisinin therapies, such as chloroquine and sulphadoxine-pyrimethamine, were widely available (> 95% of outlets) as compared to first-line quality-assured ACT (< 25%). In the public/not-for-profit sector, first-line quality-assured ACT was available for free in all countries except Benin and the DRC (US$1.29 [Inter Quartile Range (IQR): $1.29-$1.29] and $0.52[IQR: $0.00-$1.29] per adult equivalent dose respectively). In the private sector, first-line quality-assured ACT was 5-24 times more expensive than non-artemisinin therapies. The exception was Madagascar where, due to national social marketing of subsidized ACT, the price of first-line quality-assured ACT ($0.14 [IQR: $0.10, $0.57]) was significantly lower than the most popular treatment (chloroquine, $0.36 [IQR: $0.36, $0.36]). Quality-assured ACT accounted for less than 25% of total anti-malarial volumes; private-sector quality-assured ACT volumes represented less than 6% of the total market share

  8. Prices and mark-ups on antimalarials: evidence from nationally representative studies in six malaria-endemic countries.

    PubMed

    Palafox, Benjamin; Patouillard, Edith; Tougher, Sarah; Goodman, Catherine; Hanson, Kara; Kleinschmidt, Immo; Torres Rueda, Sergio; Kiefer, Sabine; O'Connell, Kate; Zinsou, Cyprien; Phok, Sochea; Akulayi, Louis; Arogundade, Ekundayo; Buyungo, Peter; Mpasela, Felton; Poyer, Stephen; Chavasse, Desmond

    2016-03-01

    The private for-profit sector is an important source of treatment for malaria. However, private patients face high prices for the recommended treatment for uncomplicated malaria, artemisinin combination therapies (ACTs), which makes them more likely to receive cheaper, less effective non-artemisinin therapies (nATs). This study seeks to better understand consumer antimalarial prices by documenting and exploring the pricing behaviour of retailers and wholesalers. Using data collected in 2009-10, we present survey estimates of antimalarial retail prices, and wholesale- and retail-level price mark-ups from six countries (Benin, Cambodia, the Democratic Republic of Congo, Nigeria, Uganda and Zambia), along with qualitative findings on factors affecting pricing decisions. Retail prices were lowest for nATs, followed by ACTs and artemisinin monotherapies (AMTs). Retailers applied the highest percentage mark-ups on nATs (range: 40% in Nigeria to 100% in Cambodia and Zambia), whereas mark-ups on ACTs (range: 22% in Nigeria to 71% in Zambia) and AMTs (range: 22% in Nigeria to 50% in Uganda) were similar in magnitude, but lower than those applied to nATs. Wholesale mark-ups were generally lower than those at retail level, and were similar across antimalarial categories in most countries. When setting prices wholesalers and retailers commonly considered supplier prices, prevailing market prices, product availability, product characteristics and the costs related to transporting goods, staff salaries and maintaining a property. Price discounts were regularly used to encourage sales and were sometimes used by wholesalers to reward long-term customers. Pricing constraints existed only in Benin where wholesaler and retailer mark-ups are regulated; however, unlicensed drug vendors based in open-air markets did not adhere to the pricing regime. These findings indicate that mark-ups on antimalarials are reasonable. Therefore, improving ACT affordability would be most readily

  9. Prices and mark-ups on antimalarials: evidence from nationally representative studies in six malaria-endemic countries

    PubMed Central

    Palafox, Benjamin; Patouillard, Edith; Tougher, Sarah; Goodman, Catherine; Hanson, Kara; Kleinschmidt, Immo; Torres Rueda, Sergio; Kiefer, Sabine; O’Connell, Kate; Zinsou, Cyprien; Phok, Sochea; Akulayi, Louis; Arogundade, Ekundayo; Buyungo, Peter; Mpasela, Felton; Poyer, Stephen; Chavasse, Desmond

    2016-01-01

    The private for-profit sector is an important source of treatment for malaria. However, private patients face high prices for the recommended treatment for uncomplicated malaria, artemisinin combination therapies (ACTs), which makes them more likely to receive cheaper, less effective non-artemisinin therapies (nATs). This study seeks to better understand consumer antimalarial prices by documenting and exploring the pricing behaviour of retailers and wholesalers. Using data collected in 2009–10, we present survey estimates of antimalarial retail prices, and wholesale- and retail-level price mark-ups from six countries (Benin, Cambodia, the Democratic Republic of Congo, Nigeria, Uganda and Zambia), along with qualitative findings on factors affecting pricing decisions. Retail prices were lowest for nATs, followed by ACTs and artemisinin monotherapies (AMTs). Retailers applied the highest percentage mark-ups on nATs (range: 40% in Nigeria to 100% in Cambodia and Zambia), whereas mark-ups on ACTs (range: 22% in Nigeria to 71% in Zambia) and AMTs (range: 22% in Nigeria to 50% in Uganda) were similar in magnitude, but lower than those applied to nATs. Wholesale mark-ups were generally lower than those at retail level, and were similar across antimalarial categories in most countries. When setting prices wholesalers and retailers commonly considered supplier prices, prevailing market prices, product availability, product characteristics and the costs related to transporting goods, staff salaries and maintaining a property. Price discounts were regularly used to encourage sales and were sometimes used by wholesalers to reward long-term customers. Pricing constraints existed only in Benin where wholesaler and retailer mark-ups are regulated; however, unlicensed drug vendors based in open-air markets did not adhere to the pricing regime. These findings indicate that mark-ups on antimalarials are reasonable. Therefore, improving ACT affordability would be most readily

  10. Examination of the Cytotoxic and Embryotoxic Potential and Underlying Mechanisms of Next-Generation Synthetic Trioxolane and Tetraoxane Antimalarials

    PubMed Central

    Copple, Ian M; Mercer, Amy E; Firman, James; Donegan, Gail; Herpers, Bram; Wong, Michael HL; Chadwick, James; Bringela, Andreia D; Cristiano, Maria LS; van de Water, Bob; Ward, Stephen A; O’Neill, Paul M; Park, B Kevin

    2012-01-01

    Semisynthetic artemisinin-based therapies are the first-line treatment for P. falciparum malaria, but next-generation synthetic drug candidates are urgently required to improve availability and respond to the emergence of artemisinin-resistant parasites. Artemisinins are embryotoxic in animal models and induce apoptosis in sensitive mammalian cells. Understanding the cytotoxic propensities of antimalarial drug candidates is crucial to their successful development and utilization. Here, we demonstrate that, similarly to the model artemisinin artesunate (ARS), a synthetic tetraoxane drug candidate (RKA182) and a trioxolane equivalent (FBEG100) induce embryotoxicity and depletion of primitive erythroblasts in a rodent model. We also show that RKA182, FBEG100 and ARS are cytotoxic toward a panel of established and primary human cell lines, with caspase-dependent apoptosis and caspase-independent necrosis underlying the induction of cell death. Although the toxic effects of RKA182 and FBEG100 proceed more rapidly and are relatively less cell-selective than that of ARS, all three compounds are shown to be dependent upon heme, iron and oxidative stress for their ability to induce cell death. However, in contrast to previously studied artemisinins, the toxicity of RKA182 and FBEG100 is shown to be independent of general chemical decomposition. Although tetraoxanes and trioxolanes have shown promise as next-generation antimalarials, the data described here indicate that adverse effects associated with artemisinins, including embryotoxicity, cannot be ruled out with these novel compounds, and a full understanding of their toxicological actions will be central to the continuing design and development of safe and effective drug candidates which could prove important in the fight against malaria. PMID:22669474

  11. Examination of the cytotoxic and embryotoxic potential and underlying mechanisms of next-generation synthetic trioxolane and tetraoxane antimalarials.

    PubMed

    Copple, Ian M; Mercer, Amy E; Firman, James; Donegan, Gail; Herpers, Bram; Wong, Michael Hl; Chadwick, James; Bringela, Andreia D; Cristiano, Maria L S; van de Water, Bob; Ward, Stephen A; O'Neill, Paul M; Park, B Kevin

    2012-01-01

    Semisynthetic artemisinin-based therapies are the first-line treatment for P. falciparum malaria, but next-generation synthetic drug candidates are urgently required to improve availability and respond to the emergence of artemisinin-resistant parasites. Artemisinins are embryotoxic in animal models and induce apoptosis in sensitive mammalian cells. Understanding the cytotoxic propensities of antimalarial drug candidates is crucial to their successful development and utilization. Here, we demonstrate that, similarly to the model artemisinin artesunate (ARS), a synthetic tetraoxane drug candidate (RKA182) and a trioxolane equivalent (FBEG100) induce embryotoxicity and depletion of primitive erythroblasts in a rodent model. We also show that RKA182, FBEG100 and ARS are cytotoxic toward a panel of established and primary human cell lines, with caspase-dependent apoptosis and caspase-independent necrosis underlying the induction of cell death. Although the toxic effects of RKA182 and FBEG100 proceed more rapidly and are relatively less cell-selective than that of ARS, all three compounds are shown to be dependent upon heme, iron and oxidative stress for their ability to induce cell death. However, in contrast to previously studied artemisinins, the toxicity of RKA182 and FBEG100 is shown to be independent of general chemical decomposition. Although tetraoxanes and trioxolanes have shown promise as next-generation antimalarials, the data described here indicate that adverse effects associated with artemisinins, including embryotoxicity, cannot be ruled out with these novel compounds, and a full understanding of their toxicological actions will be central to the continuing design and development of safe and effective drug candidates which could prove important in the fight against malaria. PMID:22669474

  12. Cell-based medicinal chemistry optimization of high-throughput screening (HTS) hits for orally active antimalarials. Part 1: challenges in potency and absorption, distribution, metabolism, excretion/pharmacokinetics (ADME/PK).

    PubMed

    Chatterjee, Arnab K

    2013-10-24

    Malaria represents a significant health issue, and novel and effective drugs are needed to address parasite resistance that has emerged to the current drug arsenal. Antimalarial drug discovery has historically benefited from a whole-cell (phenotypic) screening approach to identify lead molecules. This approach has been utilized by several groups to optimize weakly active antimalarial pharmacophores, such as the quinolone scaffold, to yield potent and highly efficacious compounds that are now poised to enter clinical trials. More recently, GNF/Novartis, GSK, and others have employed the same approach in high-throughput screening (HTS) of large compound libraries to find novel scaffolds that have also been optimized to clinical candidates by GNF/Novartis. This perspective outlines some of the inherent challenges in cell-based medicinal chemistry optimization, including optimization of oral exposure and hERG activity.

  13. Antimalarial evaluation of the chemical constituents of hairy root culture of Bixa orellana L.

    PubMed

    Zhai, Bo; Clark, Julie; Ling, Taotao; Connelly, Michele; Medina-Bolivar, Fabricio; Rivas, Fatima

    2013-01-01

    Over 216 million malaria cases are reported annually worldwide and about a third of these cases, primarily children under the age of five years old, will not survive the infection. Despite this significant world health impact, only a limited number of therapeutic agents are currently available. The lack of scaffold diversity poses a threat in the event that multi-drug-resistant strains emerge. Terrestrial natural products have provided a major source of chemical diversity for starting materials in many FDA approved drugs over the past century. Bixa orellana L. is a popular plant used in South America for the treatment of malaria. In search of new potential therapeutic agents, the chemical constituents of a selected hairy root culture line of Bixa orellana L. were characterized utilizing NMR and mass spectrometry methods, followed by its biological evaluation against malaria strains 3D7 and K1. The crude extract and its isolated compounds demonstrated EC50 values in the micromolar range. Herein, we report our findings on the chemical constituents of Bixa orellana L. from hairy roots responsible for the observed antimalarial activity. PMID:24406786

  14. 21 CFR 212.20 - What activities must I perform to ensure drug quality?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... operations. You must oversee production operations to ensure that each PET drug meets the requirements of the... of a PET drug. (c) Specifications and processes. You must approve or reject, before implementation..., and purity of a PET drug. You must demonstrate that any change does not adversely affect the...

  15. A high efficiency, high quality and low cost internal regulated bioanalytical laboratory to support drug development needs.

    PubMed

    Song, Yan; Dhodda, Raj; Zhang, Jun; Sydor, Jens

    2014-05-01

    In the recent past, we have seen an increase in the outsourcing of bioanalysis in pharmaceutical companies in support of their drug development pipeline. This trend is largely driven by the effort to reduce internal cost, especially in support of late-stage pipeline assets where established bioanalytical assays are used to analyze a large volume of samples. This article will highlight our perspective of how bioanalytical laboratories within pharmaceutical companies can be developed into the best partner in the advancement of drug development pipelines with high-quality support at competitive cost.

  16. Effect of a Primary Care based Brief Intervention Trial among Risky Drug Users on Health-related Quality of Life

    PubMed Central

    Baumeister, Sebastian E.; Gelberg, Lillian; Leake, Barbara D.; Yacenda-Murphy, Julia; Vahidi, Mani; Andersen, Ronald M.

    2014-01-01

    Background Improvement in quality of life (QOL) is a long term goal of drug treatment. Although some brief interventions have been found to reduce illicit drug use, no trial among adult risky (moderate non-dependent) drug users has tested effects on health-related quality of life. Methods A single-blind randomized controlled trial of patients enrolled from February 2011 to November 2012 was conducted in waiting rooms of five federally qualified health centers. 413 adult primary care patients were identified as risky drug users using the WHO-ASSIST and 334 (81% response; 171 intervention, 163 control) consented to participate in the trial. Three-month follow-ups were completed by 261 patients (78%). Intervention patients received the QUIT intervention of brief clinician advice and up to two drug-use health telephone sessions. The control group received usual care and information on cancer screening. Outcomes were three-month changes in the Short Form Health Survey (SF-12) mental health component summary score (MCS) and physical health component summary score (PCS). Results The average treatment effect (ATE) was non-significant for MCS (0.2 points, p-value=0.87) and marginally significant for PCS (1.7 points, p-value=0.08). The average treatment effect on the treated (ATT) was 0.1 (p-value=0.93) for MCS and 1.9 (p-value=0.056) for PCS. The effe