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1.
Proc Natl Acad Sci U S A ; 116(4): 1414-1419, 2019 01 22.
Article in English | MEDLINE | ID: mdl-30617067

ABSTRACT

Onchocerciasis and lymphatic filariasis are two neglected tropical diseases that together affect ∼157 million people and inflict severe disability. Both diseases are caused by parasitic filarial nematodes with elimination efforts constrained by the lack of a safe drug that can kill the adult filaria (macrofilaricide). Previous proof-of-concept human trials have demonstrated that depleting >90% of the essential nematode endosymbiont bacterium, Wolbachia, using antibiotics, can lead to permanent sterilization of adult female parasites and a safe macrofilaricidal outcome. AWZ1066S is a highly specific anti-Wolbachia candidate selected through a lead optimization program focused on balancing efficacy, safety and drug metabolism/pharmacokinetic (DMPK) features of a thienopyrimidine/quinazoline scaffold derived from phenotypic screening. AWZ1066S shows superior efficacy to existing anti-Wolbachia therapies in validated preclinical models of infection and has DMPK characteristics that are compatible with a short therapeutic regimen of 7 days or less. This candidate molecule is well-positioned for onward development and has the potential to make a significant impact on communities affected by filariasis.


Subject(s)
Anti-Bacterial Agents/pharmacology , Wolbachia/drug effects , Animals , Elephantiasis, Filarial/drug therapy , Elephantiasis, Filarial/microbiology , Female , Male , Mice , Mice, SCID , Onchocerciasis/drug therapy , Onchocerciasis/microbiology , Pyrimidines/pharmacology , Quinazolines/pharmacology
2.
Br J Clin Pharmacol ; 87(4): 2078-2088, 2021 04.
Article in English | MEDLINE | ID: mdl-33085781

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been declared a global pandemic and urgent treatment and prevention strategies are needed. Nitazoxanide, an anthelmintic drug, has been shown to exhibit in vitro activity against SARS-CoV-2. The present study used physiologically based pharmacokinetic (PBPK) modelling to inform optimal doses of nitazoxanide capable of maintaining plasma and lung tizoxanide exposures above the reported SARS-CoV-2 EC90 . METHODS: A whole-body PBPK model was validated against available pharmacokinetic data for healthy individuals receiving single and multiple doses between 500 and 4000 mg with and without food. The validated model was used to predict doses expected to maintain tizoxanide plasma and lung concentrations above the EC90 in >90% of the simulated population. PopDes was used to estimate an optimal sparse sampling strategy for future clinical trials. RESULTS: The PBPK model was successfully validated against the reported human pharmacokinetics. The model predicted optimal doses of 1200 mg QID, 1600 mg TID and 2900 mg BID in the fasted state and 700 mg QID, 900 mg TID and 1400 mg BID when given with food. For BID regimens an optimal sparse sampling strategy of 0.25, 1, 3 and 12 hours post dose was estimated. CONCLUSION: The PBPK model predicted tizoxanide concentrations within doses of nitazoxanide already given to humans previously. The reported dosing strategies provide a rational basis for design of clinical trials with nitazoxanide for the treatment or prevention of SARS-CoV-2 infection. A concordant higher dose of nitazoxanide is now planned for investigation in the seamless phase I/IIa AGILE trial.


Subject(s)
Antiviral Agents/administration & dosage , COVID-19 Drug Treatment , COVID-19/prevention & control , Drug Repositioning , Models, Biological , Nitro Compounds/administration & dosage , Thiazoles/administration & dosage , Adult , Antiviral Agents/blood , Antiviral Agents/pharmacokinetics , COVID-19/blood , Computer Simulation , Drug Dosage Calculations , Female , Humans , Lung/metabolism , Male , Middle Aged , Nitro Compounds/blood , Nitro Compounds/pharmacokinetics , Reproducibility of Results , Thiazoles/blood , Thiazoles/pharmacokinetics , Tissue Distribution , Young Adult
3.
Emerg Infect Dis ; 26(11): 2770-2771, 2020 11.
Article in English | MEDLINE | ID: mdl-32917294

ABSTRACT

PCR of upper respiratory specimens is the diagnostic standard for severe acute respiratory syndrome coronavirus 2 infection. However, saliva sampling is an easy alternative to nasal and throat swabbing. We found similar viral loads in saliva samples and in nasal and throat swab samples from 110 patients with coronavirus disease.


Subject(s)
Betacoronavirus/isolation & purification , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Saliva/virology , Adult , Aged , COVID-19 , COVID-19 Testing , Female , Humans , Male , Middle Aged , Nose/virology , Pandemics , Pharynx/virology , SARS-CoV-2 , Viral Load
4.
Clin Infect Dis ; 69(7): 1112-1119, 2019 09 13.
Article in English | MEDLINE | ID: mdl-30590537

ABSTRACT

BACKGROUND: Ivermectin is being considered for mass drug administration for malaria, due to its ability to kill mosquitoes feeding on recently treated individuals. In a recent trial, 3-day courses of 300 and 600 mcg/kg/day were shown to kill Anopheles mosquitoes for at least 28 days post-treatment when fed patients' venous blood using membrane feeding assays. Direct skin feeding on humans may lead to higher mosquito mortality, as ivermectin capillary concentrations are higher. We compared mosquito mortality following direct skin and membrane feeding. METHODS: We conducted a mosquito feeding study, nested within a randomized, double-blind, placebo-controlled trial of 141 adults with uncomplicated malaria in Kenya, comparing 3 days of ivermectin 300 mcg/kg/day, ivermectin 600 mcg/kg/day, or placebo, all co-administered with 3 days of dihydroartemisinin-piperaquine. On post-treatment day 7, direct skin and membrane feeding assays were conducted using laboratory-reared Anopheles gambiae sensu stricto. Mosquito survival was assessed daily for 28 days post-feeding. RESULTS: Between July 20, 2015, and May 7, 2016, 69 of 141 patients participated in both direct skin and membrane feeding (placebo, n = 23; 300 mcg/kg/day, n = 24; 600 mcg/kg/day, n = 22). The 14-day post-feeding mortality for mosquitoes fed 7 days post-treatment on blood from pooled patients in both ivermectin arms was similar with direct skin feeding (mosquitoes observed, n = 2941) versus membrane feeding (mosquitoes observed, n = 7380): cumulative mortality (risk ratio 0.99, 95% confidence interval [CI] 0.95-1.03, P = .69) and survival time (hazard ratio 0.96, 95% CI 0.91-1.02, P = .19). Results were consistent by sex, by body mass index, and across the range of ivermectin capillary concentrations studied (0.72-73.9 ng/mL). CONCLUSIONS: Direct skin feeding and membrane feeding on day 7 resulted in similar mosquitocidal effects of ivermectin across a wide range of drug concentrations, suggesting that the mosquitocidal effects seen with membrane feeding accurately reflect those of natural biting. Membrane feeding, which is more patient friendly and ethically acceptable, can likely reliably be used to assess ivermectin's mosquitocidal efficacy. CLINICAL TRIALS REGISTRATION: NCT02511353.


Subject(s)
Antiparasitic Agents/administration & dosage , Culicidae/drug effects , Insecticides/administration & dosage , Ivermectin/administration & dosage , Adult , Animals , Anopheles/drug effects , Antiparasitic Agents/pharmacokinetics , Feeding Behavior , Female , Humans , Ivermectin/pharmacokinetics , Malaria/parasitology , Malaria/prevention & control , Male , Mosquito Control , Young Adult
5.
Article in English | MEDLINE | ID: mdl-31611354

ABSTRACT

Clinical studies of new antitubercular drugs are costly and time-consuming. Owing to the extensive tuberculosis (TB) treatment periods, the ability to identify drug candidates based on their predicted clinical efficacy is vital to accelerate the pipeline of new therapies. Recent failures of preclinical models in predicting the activity of fluoroquinolones underline the importance of developing new and more robust predictive tools that will optimize the design of future trials. Here, we used high-content imaging screening and pharmacodynamic intracellular (PDi) modeling to identify and prioritize fluoroquinolones for TB treatment. In a set of studies designed to validate this approach, we show moxifloxacin to be the most effective fluoroquinolone, and PDi modeling-based Monte Carlo simulations accurately predict negative culture conversion (sputum sterilization) rates compared to eight independent clinical trials. In addition, PDi-based simulations were used to predict the risk of relapse. Our analyses show that the duration of treatment following culture conversion can be used to predict the relapse rate. These data further support that PDi-based modeling offers a much-needed decision-making tool for the TB drug development pipeline.


Subject(s)
Antitubercular Agents/pharmacology , Antitubercular Agents/pharmacokinetics , Fluoroquinolones/pharmacology , Fluoroquinolones/pharmacokinetics , Models, Biological , Tuberculosis, Pulmonary/drug therapy , Tuberculosis, Pulmonary/metabolism , Cell Line , Computer Simulation , Decision Support Techniques , Drug Development , Humans , Macrophages/drug effects , Macrophages/microbiology , Monte Carlo Method , Moxifloxacin/pharmacokinetics , Moxifloxacin/pharmacology , Mycobacterium tuberculosis/drug effects , THP-1 Cells , Tuberculosis, Multidrug-Resistant/drug therapy , Tuberculosis, Multidrug-Resistant/metabolism
6.
Bioorg Med Chem ; 26(11): 2996-3005, 2018 07 15.
Article in English | MEDLINE | ID: mdl-29779669

ABSTRACT

A series of aryl carboxamide and benzylamino dispiro 1,2,4,5-tetraoxane analogues have been designed and synthesized in a short synthetic sequence from readily available starting materials. From this series of endoperoxides, molecules with in vitro IC50s versus Plasmodium falciparum (3D7) as low as 0.84 nM were identified. Based on an assessment of blood stability and in vitro microsomal stability, N205 (10a) was selected for rodent pharmacokinetic and in vivo antimalarial efficacy studies in the mouse Plasmodium berghei and Plasmodium falciparum Pf3D70087/N9 severe combined immunodeficiency (SCID) mouse models. The results indicate that the 4-benzylamino derivatives have excellent profiles with a representative of this series, N205, an excellent starting point for further lead optimization studies.


Subject(s)
Antimalarials/therapeutic use , Malaria , Morpholines/chemical synthesis , Plasmodium falciparum , Tetraoxanes/chemical synthesis , Administration, Oral , Animals , Antimalarials/chemical synthesis , Antimalarials/chemistry , Disease Models, Animal , Drug Stability , Humans , Inhibitory Concentration 50 , Malaria/drug therapy , Mice , Morpholines/chemistry , Morpholines/therapeutic use , Plasmodium falciparum/drug effects , Rats , Tetraoxanes/chemistry , Tetraoxanes/therapeutic use
7.
Pharm Res ; 34(12): 2517-2531, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28616685

ABSTRACT

PURPOSE: Polyamidoamine (PAMAM) dendrimers are a promising class of nanocarrier with applications in both small and large molecule drug delivery. Here we report a comprehensive evaluation of the uptake and transport pathways that contribute to the lung disposition of dendrimers. METHODS: Anionic PAMAM dendrimers and control dextran probes were applied to an isolated perfused rat lung (IPRL) model and lung epithelial monolayers. Endocytosis pathways were examined in primary alveolar epithelial cultures by confocal microscopy. Molecular interactions of dendrimers with protein and lipid lung fluid components were studied using small angle neutron scattering (SANS). RESULTS: Dendrimers were absorbed across the intact lung via a passive, size-dependent transport pathway at rates slower than dextrans of similar molecular sizes. SANS investigations of concentration-dependent PAMAM transport in the IPRL confirmed no aggregation of PAMAMs with either albumin or dipalmitoylphosphatidylcholine lung lining fluid components. Distinct endocytic compartments were identified within primary alveolar epithelial cells and their functionality in the rapid uptake of fluorescent dendrimers and model macromolecular probes was confirmed by co-localisation studies. CONCLUSIONS: PAMAM dendrimers display favourable lung biocompatibility but modest lung to blood absorption kinetics. These data support the investigation of dendrimer-based carriers for controlled-release drug delivery to the deep lung.


Subject(s)
Dendrimers/metabolism , Drug Carriers/metabolism , Lung/metabolism , Alveolar Epithelial Cells/metabolism , Animals , Anions/metabolism , Biological Transport , Cell Line , Cells, Cultured , Endocytosis , Rats
8.
Antimicrob Agents Chemother ; 60(12): 7340-7346, 2016 12.
Article in English | MEDLINE | ID: mdl-27697762

ABSTRACT

Liposomal amphotericin B (LAmB) is widely used in the treatment of invasive fungal disease (IFD) in adults and children. There are relatively limited pharmacokinetic (PK) data to inform optimal dosing in children that achieves systemic drug exposures comparable to those of adults. Our objective was to describe the pharmacokinetics of LAmB in children aged 1 to 17 years with suspected or documented IFD. Thirty-five children were treated with LAmB at doses of 2.5 to 10 mg kg-1 daily. Samples were taken at baseline and at 0.5- to 2.0-h intervals for 24 h after receipt of the first dose (n = 35 patients) and on the final day of therapy (n = 25 patients). LAmB was measured using high-performance liquid chromatography (HPLC). The relationship between drug exposure and development of toxicity was explored. An evolution in PK was observed during the course of therapy, resulting in a proportion of patients (n = 13) having significantly higher maximum serum concentrations (Cmax) and areas under the concentration-time curve from 0 to 24 h (AUC0-24) later in the course of therapy, without evidence of drug accumulation (trough plasma concentration accumulation ratio of <1.2). The fit of a 2-compartment model incorporating weight and an exponential decay function describing volume of distribution best described the data. There was a statistically significant relationship between mean AUC0-24 and probability of nephrotoxicity (odds ratio, 2.37; 95% confidence interval, 1.84 to 3.22; P = 0.004). LAmB exhibits nonlinear pharmacokinetics. A third of children appear to experience a time-dependent change in PK, which is not explained by weight, maturation, or observed clinical factors.


Subject(s)
Amphotericin B/pharmacokinetics , Amphotericin B/therapeutic use , Antifungal Agents/pharmacokinetics , Antifungal Agents/therapeutic use , Immunocompromised Host , Invasive Fungal Infections/drug therapy , Adolescent , Amphotericin B/adverse effects , Antifungal Agents/adverse effects , Area Under Curve , Child , Child, Preschool , Chromatography, High Pressure Liquid , Female , Humans , Infant , Male
10.
Malar J ; 15(1): 344, 2016 07 07.
Article in English | MEDLINE | ID: mdl-27388207

ABSTRACT

BACKGROUND: The search for highly effective anti-malarial therapies has gathered pace and recent years have seen a number of promising single and combined therapies reach the late stages of development. A key drug development challenge is the need for early assessment of the clinical utility of new drug leads as it is often unclear for developers whether efforts should be focused on efficacy or metabolic stability/exposure or indeed whether the continuation of iterative QSAR (quantitative structure-activity and relationships) cycles of medicinal chemistry and biological testing will translate to improved clinical efficacy. Pharmacokinetic and pharmacodynamic (PK/PD)-based measurements available from in vitro studies can be used for such clinical predictions. However, these predictions often require bespoke mathematical PK/PD modelling expertise and are normally performed after candidate development and, therefore, not during the pre-clinical development phase when such decisions need to be made. METHODS: An internet-based tool has been developed using STELLA(®) software. The tool simulates multiple differential equations that describe anti-malarial PK/PD relationships where the user can easily input PK/PD parameters. The tool utilizes a simple stop-light system to indicate the efficacy of each combination of parameters. This tool, called OptiMal-PK, additionally allows for the investigation of the effect of drug combinations with known or custom compounds. RESULTS: The results of simulations obtained from OptiMal-PK were compared to a previously published and validated mathematical model on which this tool is based. The tool has also been used to simulate the PK/PD relationship for a number of existing anti-malarial drugs in single or combined treatment. Simulations were predictive of the published clinical parasitological clearance activities for these existing therapies. CONCLUSIONS: OptiMal-PK is designed to be implemented by medicinal chemists and pharmacologists during the pre-clinical anti-malarial drug development phase to explore the impact of different PK/PD parameters upon the predicted clinical activity of any new compound. It can help investigators to identify which pharmacological features of a compound are most important to the clinical performance of a new chemical entity and how partner drugs could potentially improve the activity of existing therapies.


Subject(s)
Antimalarials/pharmacology , Antimalarials/pharmacokinetics , Drug Evaluation, Preclinical/methods , Internet , Malaria/drug therapy , Software , Antimalarials/isolation & purification , Humans , Models, Theoretical
11.
Front Immunol ; 15: 1360063, 2024.
Article in English | MEDLINE | ID: mdl-38558809

ABSTRACT

Hepatocellular carcinoma (HCC) and solid cancers with liver metastases are indications with high unmet medical need. Interleukin-12 (IL-12) is a proinflammatory cytokine with substantial anti-tumor properties, but its therapeutic potential has not been realized due to severe toxicity. Here, we show that orthotopic liver tumors in mice can be treated by targeting hepatocytes via systemic delivery of adeno-associated virus (AAV) vectors carrying the murine IL-12 gene. Controlled cytokine production was achieved in vivo by using the tetracycline-inducible K19 riboswitch. AAV-mediated expression of IL-12 led to STAT4 phosphorylation, interferon-γ (IFNγ) production, infiltration of T cells and, ultimately, tumor regression. By detailed analyses of efficacy and tolerability in healthy and tumor-bearing animals, we could define a safe and efficacious vector dose. As a potential clinical candidate, we characterized vectors carrying the human IL-12 (huIL-12) gene. In mice, bioactive human IL-12 was expressed in a vector dose-dependent manner and could be induced by tetracycline, suggesting tissue-specific AAV vectors with riboswitch-controlled expression of highly potent proinflammatory cytokines as an attractive approach for vector-based cancer immunotherapy.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Riboswitch , Mice , Humans , Animals , Liver Neoplasms/genetics , Liver Neoplasms/therapy , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/therapy , Carcinoma, Hepatocellular/pathology , Genetic Therapy , Interleukin-12/genetics , Interleukin-12/metabolism , Tetracycline/pharmacology
12.
Front Microbiol ; 15: 1346068, 2024.
Article in English | MEDLINE | ID: mdl-38362501

ABSTRACT

Lymphatic filariasis and onchocerciasis are two major neglected tropical diseases that are responsible for causing severe disability in 50 million people worldwide, whilst veterinary filariasis (heartworm) is a potentially lethal parasitic infection of companion animals. There is an urgent need for safe, short-course curative (macrofilaricidal) drugs to eliminate these debilitating parasite infections. We investigated combination treatments of the novel anti-Wolbachia azaquinazoline small molecule, AWZ1066S, with benzimidazole drugs (albendazole or oxfendazole) in up to four different rodent filariasis infection models: Brugia malayi-CB.17 SCID mice, B. malayi-Mongolian gerbils, B. pahangi-Mongolian gerbils, and Litomosoides sigmodontis-Mongolian gerbils. Combination treatments synergised to elicit threshold (>90%) Wolbachia depletion from female worms in 5 days of treatment, using 2-fold lower dose-exposures of AWZ1066S than monotherapy. Short-course lowered dose AWZ1066S-albendazole combination treatments also delivered partial adulticidal activities and/or long-lasting inhibition of embryogenesis, resulting in complete transmission blockade in B. pahangi and L. sigmodontis gerbil models. We determined that short-course AWZ1066S-albendazole co-treatment significantly augmented the depletion of Wolbachia populations within both germline and hypodermal tissues of B. malayi female worms and in hypodermal tissues in male worms, indicating that anti-Wolbachia synergy is not limited to targeting female embryonic tissues. Our data provides pre-clinical proof-of-concept that sub-seven-day combinations of rapid-acting novel anti-Wolbachia agents with benzimidazole anthelmintics are a promising curative and transmission-blocking drug treatment strategy for filarial diseases of medical and veterinary importance.

13.
Pharmaceuticals (Basel) ; 16(2)2023 Jan 23.
Article in English | MEDLINE | ID: mdl-37009844

ABSTRACT

With artemisinin-resistant Plasmodium falciparum parasites emerging in Africa, the need for new antimalarial chemotypes is persistently high. The ideal pharmacodynamic parameters of a candidate drug are a rapid onset of action and a fast rate of parasite killing or clearance. To determine these parameters, it is essential to discriminate viable from nonviable parasites, which is complicated by the fact that viable parasites can be metabolically inactive, whilst dying parasites can still be metabolically active and morphologically unaffected. Standard growth inhibition assays, read out via microscopy or [3H] hypoxanthine incorporation, cannot reliably discriminate between viable and nonviable parasites. Conversely, the in vitro parasite reduction ratio (PRR) assay is able to measure viable parasites with high sensitivity. It provides valuable pharmacodynamic parameters, such as PRR, 99.9% parasite clearance time (PCT99.9%) and lag phase. Here we report the development of the PRR assay version 2 (V2), which comes with a shorter assay duration, optimized quality controls and an objective, automated analysis pipeline that systematically estimates PRR, PCT99.9% and lag time and returns meaningful secondary parameters such as the maximal killing rate of a drug (Emax) at the assayed concentration. These parameters can be fed directly into pharmacokinetic/pharmacodynamic models, hence aiding and standardizing lead selection, optimization, and dose prediction.

14.
ACS Infect Dis ; 9(2): 221-238, 2023 02 10.
Article in English | MEDLINE | ID: mdl-36606559

ABSTRACT

Mycobacterium tuberculosis cytochrome bd quinol oxidase (cyt bd), the alternative terminal oxidase of the respiratory chain, has been identified as playing a key role during chronic infection and presents a putative target for the development of novel antitubercular agents. Here, we report confirmation of successful heterologous expression of M. tuberculosis cytochrome bd. The heterologous M. tuberculosis cytochrome bd expression system was used to identify a chemical series of inhibitors based on the 2-aryl-quinolone pharmacophore. Cytochrome bd inhibitors displayed modest efficacy in M. tuberculosis growth suppression assays together with a bacteriostatic phenotype in time-kill curve assays. Significantly, however, inhibitor combinations containing our front-runner cyt bd inhibitor CK-2-63 with either cyt bcc-aa3 inhibitors (e.g., Q203) and/or adenosine triphosphate (ATP) synthase inhibitors (e.g., bedaquiline) displayed enhanced efficacy with respect to the reduction of mycobacterium oxygen consumption, growth suppression, and in vitro sterilization kinetics. In vivo combinations of Q203 and CK-2-63 resulted in a modest lowering of lung burden compared to treatment with Q203 alone. The reduced efficacy in the in vivo experiments compared to in vitro experiments was shown to be a result of high plasma protein binding and a low unbound drug exposure at the target site. While further development is required to improve the tractability of cyt bd inhibitors for clinical evaluation, these data support the approach of using small-molecule inhibitors to target multiple components of the branched respiratory chain of M. tuberculosis as a combination strategy to improve therapeutic and pharmacokinetic/pharmacodynamic (PK/PD) indices related to efficacy.


Subject(s)
Antitubercular Agents , Mycobacterium tuberculosis , Quinolones , Antitubercular Agents/pharmacology , Cytochromes/antagonists & inhibitors , Electron Transport Complex IV/antagonists & inhibitors , Mycobacterium tuberculosis/drug effects , Quinolones/pharmacology
15.
Sci Rep ; 12(1): 1416, 2022 01 26.
Article in English | MEDLINE | ID: mdl-35082404

ABSTRACT

The control of the COVID-19 pandemic in the UK has necessitated restrictions on amateur and professional sports due to the perceived infection risk to competitors, via direct person to person transmission, or possibly via the surfaces of sports equipment. The sharing of sports equipment such as tennis balls was therefore banned by some sport's governing bodies. We sought to investigate the potential of sporting equipment as transmission vectors of SARS-CoV-2. Ten different types of sporting equipment, including balls from common sports, were inoculated with 40 µl droplets containing clinically relevant concentrations of live SARS-CoV-2 virus. Materials were then swabbed at time points relevant to sports (1, 5, 15, 30, 90 min). The amount of live SARS-CoV-2 recovered at each time point was enumerated using viral plaque assays, and viral decay and half-life was estimated through fitting linear models to log transformed data from each material. At one minute, SARS-CoV-2 virus was recovered in only seven of the ten types of equipment with the low dose inoculum, one at five minutes and none at 15 min. Retrievable virus dropped significantly for all materials tested using the high dose inoculum with mean recovery of virus falling to 0.74% at 1 min, 0.39% at 15 min and 0.003% at 90 min. Viral recovery, predicted decay, and half-life varied between materials with porous surfaces limiting virus transmission. This study shows that there is an exponential reduction in SARS-CoV-2 recoverable from a range of sports equipment after a short time period, and virus is less transferrable from materials such as a tennis ball, red cricket ball and cricket glove. Given this rapid loss of viral load and the fact that transmission requires a significant inoculum to be transferred from equipment to the mucous membranes of another individual it seems unlikely that sports equipment is a major cause for transmission of SARS-CoV-2. These findings have important policy implications in the context of the pandemic and may promote other infection control measures in sports to reduce the risk of SARS-CoV-2 transmission and urge sports equipment manufacturers to identify surfaces that may or may not be likely to retain transferable virus.


Subject(s)
COVID-19/transmission , SARS-CoV-2/physiology , COVID-19/virology , Half-Life , Humans , Linear Models , SARS-CoV-2/isolation & purification , Sports Equipment , Surface Properties
16.
Int J Antimicrob Agents ; 59(3): 106542, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35093538

ABSTRACT

A key element for the prevention and management of coronavirus disease 2019 is the development of effective therapeutics. Drug combination strategies offer several advantages over monotherapies. They have the potential to achieve greater efficacy, to increase the therapeutic index of drugs and to reduce the emergence of drug resistance. We assessed the in vitro synergistic interaction between remdesivir and ivermectin, both approved by the US Food and Drug Administration, and demonstrated enhanced antiviral activity against severe acute respiratory syndrome coronavirus-2. Whilst the in vitro synergistic activity reported here does not support the clinical application of this combination treatment strategy due to insufficient exposure of ivermectin in vivo, the data do warrant further investigation. Efforts to define the mechanisms underpinning the observed synergistic action could lead to the development of novel treatment strategies.


Subject(s)
COVID-19 Drug Treatment , SARS-CoV-2 , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Humans , Ivermectin/pharmacology , Ivermectin/therapeutic use
17.
Methods Mol Biol ; 2296: 393-408, 2021.
Article in English | MEDLINE | ID: mdl-33977461

ABSTRACT

The human disease tuberculosis (TB) is the leading cause of death from a single infectious agent. A quarter of the world's population is estimated to be latently infected. Drug development and screening is slow and costly. We have developed a physiologically relevant assay to screen drugs against TB when inside immune cells. This chapter will describe a newly developed preclinical drug screening assay for TB, using high-content imaging and pharmacokinetic/pharmacodynamic modeling.


Subject(s)
Antitubercular Agents/pharmacology , Mycobacterium tuberculosis/drug effects , Tuberculosis/drug therapy , Bacterial Proteins/metabolism , Dose-Response Relationship, Drug , Drug Development/methods , Humans , Mycobacterium tuberculosis/metabolism , THP-1 Cells
18.
ACS Infect Dis ; 7(6): 1317-1331, 2021 06 11.
Article in English | MEDLINE | ID: mdl-33352056

ABSTRACT

The rapidly growing COVID-19 pandemic is the most serious global health crisis since the "Spanish flu" of 1918. There is currently no proven effective drug treatment or prophylaxis for this coronavirus infection. While developing safe and effective vaccines is one of the key focuses, a number of existing antiviral drugs are being evaluated for their potency and efficiency against SARS-CoV-2 in vitro and in the clinic. Here, we review the significant potential of nitazoxanide (NTZ) as an antiviral agent that can be repurposed as a treatment for COVID-19. Originally, NTZ was developed as an antiparasitic agent especially against Cryptosporidium spp.; it was later shown to possess potent activity against a broad range of both RNA and DNA viruses, including influenza A, hepatitis B and C, and coronaviruses. Recent in vitro assessment of NTZ has confirmed its promising activity against SARS-CoV-2 with an EC50 of 2.12 µM. Here we examine its drug properties, antiviral activity against different viruses, clinical trials outcomes, and mechanisms of antiviral action from the literature in order to highlight the therapeutic potential for the treatment of COVID-19. Furthermore, in preliminary PK/PD analyses using clinical data reported in the literature, comparison of simulated TIZ (active metabolite of NTZ) exposures at two doses with the in vitro potency of NTZ against SARS-CoV-2 gives further support for drug repurposing with potential in combination chemotherapy approaches. The review concludes with details of second generation thiazolides under development that could lead to improved antiviral therapies for future indications.


Subject(s)
COVID-19 , Cryptosporidiosis , Cryptosporidium , Drug Repositioning , Humans , Nitro Compounds , Pandemics , SARS-CoV-2 , Thiazoles
19.
Int J Pharm ; 579: 119187, 2020 Apr 15.
Article in English | MEDLINE | ID: mdl-32135228

ABSTRACT

The epithelial permeation of water-soluble fluorescent PAMAM dendrons based on 7H-benz[de] benzimidazo [2,1-a] isoquinoline-7-one as a fluorescent core across epithelial cell models MDCK I and MDCK II has been quantified. Hydrodynamic radii have been derived from self-diffusion coefficients obtained via pulsed-gradient spin-echo Nuclear Magnetic Resonance (PGSE-NMR). Results indicate that these dendritic molecules are molecularly disperse, non-aggregating, and only slightly larger than their parent homologues. MDCK I permeability studies across epithelial barriers show that these dendritic molecules are biocompatible with the chosen epithelial in-vitro model and can permeate across MDCK cell monolayers. Permeability is demonstrated to be a property of dendritic size and cell barrier restrictiveness indicating that paracellular mechanisms play the predominant role in the transport of these molecules.


Subject(s)
Dendrimers/chemical synthesis , Epithelial Cells/metabolism , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Permeability , Animals , Cells, Cultured , Dogs , Magnetic Resonance Spectroscopy
20.
Lancet Infect Dis ; 20(4): 498-508, 2020 04.
Article in English | MEDLINE | ID: mdl-31948767

ABSTRACT

BACKGROUND: Ivermectin is a potential new vector control tool to reduce malaria transmission. Mosquitoes feeding on a bloodmeal containing ivermectin have a reduced lifespan, meaning they are less likely to live long enough to complete sporogony and become infectious. We aimed to estimate the effect of ivermectin on malaria transmission in various scenarios of use. METHODS: We validated an existing population-level mathematical model of the effect of ivermectin mass drug administration (MDA) on the mosquito population and malaria transmission against two datasets: clinical data from a cluster- randomised trial done in Burkina Faso in 2015 wherein ivermectin was given to individuals taller than 90 cm and entomological data from a study of mosquito outcomes after ivermectin MDA for onchocerciasis or lymphatic filariasis in Burkina Faso, Senegal, and Liberia between 2008 and 2013. We extended the existing model to include a range of complementary malaria interventions (seasonal malaria chemoprevention and MDA with dihydroartemisinin-piperaquine) and to incorporate new data on higher doses of ivermectin with a longer mosquitocidal effect. We consider two ivermectin regimens: a single dose of 400 µg/kg (1 × 400 µg/kg) and three consecutive daily doses of 300 µg/kg per day (3 × 300 µg/kg). We simulated the effect of these two doses in a range of usage scenarios in different transmission settings (highly seasonal, seasonal, and perennial). We report percentage reductions in clinical incidence and slide prevalence. FINDINGS: We estimate that MDA with ivermectin will reduce prevalence and incidence and is most effective in areas with highly seasonal transmission. In a highly seasonal moderate transmission setting, three rounds of ivermectin only MDA at 3 × 300 µg/kg (rounds spaced 1 month apart) and 70% coverage is predicted to reduce clinical incidence by 71% and prevalence by 34%. We predict that adding ivermectin MDA to seasonal malaria chemoprevention in this setting would reduce clinical incidence by an additional 77% in children younger than 5 years compared with seasonal malaria chemoprevention alone; adding ivermectin MDA to MDA with dihydroartemisinin-piperaquine in this setting would reduce incidence by an additional 75% and prevalence by an additional 64% (all ages) compared with MDA with dihydroartemisinin-piperaquine alone. INTERPRETATION: Our modelling predictions suggest that ivermectin could be a valuable addition to the malaria control toolbox, both in areas with persistently high transmission where existing interventions are insufficient and in areas approaching elimination to prevent resurgence. FUNDING: Imperial College Junior Research Fellowship.


Subject(s)
Ivermectin/administration & dosage , Malaria , Mosquito Vectors , Animals , Antimalarials/therapeutic use , Artemisinins/therapeutic use , Burkina Faso/epidemiology , Child , Female , Humans , Incidence , Insecticides , Malaria/epidemiology , Malaria/prevention & control , Male , Mass Drug Administration , Prevalence , Quinolines/therapeutic use , Randomized Controlled Trials as Topic , Seasons
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