1
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Scarsi KK, Sayles H, Kapungu K, Sifuna P, Ippolito MM, Furl R, Anderson MJ, Ofimboudem JD, Chongwe G, Hutter J, Rannard SP, Owen A, Swindells S. Preferences of Patients and Providers in High-Burden Malaria Settings for Long-Acting Malaria Chemoprevention. Am J Trop Med Hyg 2023; 109:752-760. [PMID: 37604474 PMCID: PMC10551098 DOI: 10.4269/ajtmh.23-0245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/29/2023] [Indexed: 08/23/2023] Open
Abstract
Antimalarial medications are recommended for chemoprevention as part of malaria control programs to decrease the morbidity and mortality related to more than 200 million infections each year. We sought to evaluate patient and provider acceptability of malaria chemoprevention in a long-acting formulation. We administered questionnaires to patients and providers in malaria endemic districts in Kenya and Zambia. Questions explored preferences and concerns around long-acting antimalarial formulations compared with oral formulations. We recruited 202 patient respondents (Kenya, n = 102; Zambia, n = 100) and 215 provider respondents (Kenya, n = 105; Zambia, n = 110). Long-acting injection was preferred to oral pills, whereas oral pills were preferred to implant or transdermal administration by patient respondents. Of 202 patient respondents, 80% indicated that they 'definitely would try' malaria chemoprevention offered by injection instead of oral pills. Of parents or guardians, 84% of 113 responded that they 'definitely would' have their child age < 12 years and 90% of 88 'definitely would' have their child ≥12 years receive an injection for malaria prevention. Provider respondents indicated that they would be more likely to prescribe a long-acting injectable product compared with an oral product for malaria chemoprevention in adults (70%), adolescents ages 12 years and older (67%), and children <12 years (81%). Potential for prolonged adverse effects with long-acting products was the highest concern for patient respondents, while higher medication-related cost was cited as the most concerning barrier to implementation by providers. Overall, these findings indicate enthusiasm for the development of long-acting injectable antimalarials to provide individual delivery method options across age groups.
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Affiliation(s)
- Kimberly K. Scarsi
- College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska
- College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Harlan Sayles
- College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska
| | - Kelvin Kapungu
- Department of Public Health and Epidemiology, Tropical Diseases Research Centre, Ndola, Zambia
| | - Peter Sifuna
- Kombewa Clinical Research Center, Kenya Medical Research Institute (KEMRI)/U.S. Army Medical Research Directorate–Africa (USAMRD-A), Kisumu, Kenya
| | - Matthew M. Ippolito
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Johns Hopkins Malaria Research Institute, John Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Renae Furl
- College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Matthew J. Anderson
- College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska
| | | | | | - Jack Hutter
- Kombewa Clinical Research Center, Kenya Medical Research Institute (KEMRI)/U.S. Army Medical Research Directorate–Africa (USAMRD-A), Kisumu, Kenya
| | - Steven P. Rannard
- Department of Chemistry, Centre of Excellence in Long-Acting Therapeutics (CELT), University of Liverpool, Liverpool, United Kingdom
| | - Andrew Owen
- Department of Molecular and Clinical Pharmacology, Centre of Excellence in Long-acting Therapeutics (CELT), University of Liverpool, Liverpool, UK
| | - Susan Swindells
- College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska
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2
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Chang YS, Li SY, Pertinez H, Betoudji F, Lee J, Rannard SP, Owen A, Nuermberger EL, Ammerman NC. Using Dynamic Oral Dosing of Rifapentine and Rifabutin to Simulate Exposure Profiles of Long-Acting Formulations in a Mouse Model of Tuberculosis Preventive Therapy. Antimicrob Agents Chemother 2023; 67:e0048123. [PMID: 37338374 PMCID: PMC10353356 DOI: 10.1128/aac.00481-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/18/2023] [Indexed: 06/21/2023] Open
Abstract
Administration of tuberculosis preventive therapy (TPT) to individuals with latent tuberculosis infection is an important facet of global tuberculosis control. The use of long-acting injectable (LAI) drug formulations may simplify and shorten regimens for this indication. Rifapentine and rifabutin have antituberculosis activity and physiochemical properties suitable for LAI formulation, but there are limited data available for determining the target exposure profiles required for efficacy in TPT regimens. The objective of this study was to determine exposure-activity profiles of rifapentine and rifabutin to inform development of LAI formulations for TPT. We used a validated paucibacillary mouse model of TPT in combination with dynamic oral dosing of both drugs to simulate and understand exposure-activity relationships to inform posology for future LAI formulations. This work identified several LAI-like exposure profiles of rifapentine and rifabutin that, if achieved by LAI formulations, could be efficacious as TPT regimens and thus can serve as experimentally determined targets for novel LAI formulations of these drugs. We present novel methodology to understand the exposure-response relationship and inform the value proposition for investment in development of LAI formulations that have utility beyond latent tuberculosis infection.
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Affiliation(s)
- Yong S. Chang
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Si-Yang Li
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Henry Pertinez
- Centre of Excellence in Long-Acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, United Kingdom
| | - Fabrice Betoudji
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jin Lee
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Steven P. Rannard
- Centre of Excellence in Long-Acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, United Kingdom
| | - Andrew Owen
- Centre of Excellence in Long-Acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, United Kingdom
| | - Eric L. Nuermberger
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nicole C. Ammerman
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Medical Microbiology and Infectious Diseases, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
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3
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Chang YS, Li SY, Pertinez H, Betoudji F, Lee J, Rannard SP, Owen A, Nuermberger EL, Ammerman NC. Using dynamic oral dosing of rifapentine and rifabutin to simulate exposure profiles of long-acting formulations in a mouse model of tuberculosis preventive therapy. bioRxiv 2023:2023.04.12.536604. [PMID: 37090528 PMCID: PMC10120629 DOI: 10.1101/2023.04.12.536604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Administration of tuberculosis preventive therapy (TPT) to individuals with latent tuberculosis infection is an important facet of global tuberculosis control. The use of long-acting injectable (LAI) drug formulations may simplify and shorten regimens for this indication. Rifapentine and rifabutin have anti-tuberculosis activity and physiochemical properties suitable for LAI formulation, but there are limited data available for determining the target exposure profiles required for efficacy in TPT regimens. The objective of this study was to determine exposure-activity profiles of rifapentine and rifabutin to inform development of LAI formulations for TPT. We utilized a validated paucibacillary mouse model of TPT in combination with dynamic oral dosing of both drugs to simulate and understand exposure-activity relationships to inform posology for future LAI formulations. This work identified several LAI-like exposure profiles of rifapentine and rifabutin that, if achieved by LAI formulations, could be efficacious as TPT regimens and thus can serve as experimentally-determined targets for novel LAI formulations of these drugs. We present novel methodology to understand the exposure-response relationship and inform the value proposition for investment in development of LAI formulations that has utility beyond latent tuberculosis infection.
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Affiliation(s)
- Yong S. Chang
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Touro College of Osteopathic Medicine-Middletown, Middletown, New York, USA (current address)
| | - Si-Yang Li
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Henry Pertinez
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
| | - Fabrice Betoudji
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Veterinary Medicine Division, USAMRIID, Fort Detrick, Frederick, Maryland, USA (current address)
| | - Jin Lee
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Steven P. Rannard
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
| | - Andrew Owen
- Centre of Excellence in Long-acting Therapeutics (CELT), Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool, UK
| | - Eric L. Nuermberger
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nicole C. Ammerman
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Medical Microbiology and Infectious Diseases, University Medical Center Rotterdam, Erasmus MC, Rotterdam, The Netherlands
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Neary M, Box H, Sharp J, Tatham L, Curley P, Herriott J, Kijak E, Arshad U, Hobson JJ, Rajoli R, Pertinez H, Valentijn A, Dhaliwal K, McCaughan F, Rannard SP, Kipar A, Stewart JP, Owen A. Evaluation of intranasal nafamostat or camostat for SARS-CoV-2 chemoprophylaxis in Syrian golden hamsters. bioRxiv 2021:2021.07.08.451654. [PMID: 34268511 PMCID: PMC8282100 DOI: 10.1101/2021.07.08.451654] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Successful development of a chemoprophylaxis against SARS-CoV-2 could provide a tool for infection prevention implementable alongside vaccination programmes. Camostat and nafamostat are serine protease inhibitors that inhibit SARS-CoV-2 viral entry in vitro but have not been characterised for chemoprophylaxis in animal models. Clinically, nafamostat is limited to intravenous delivery and while camostat is orally available, both drugs have extremely short plasma half-lives. This study sought to determine whether intranasal dosing at 5 mg/kg twice daily was able to prevent airborne transmission of SARS-CoV-2 from infected to uninfected Syrian golden hamsters. SARS-CoV-2 viral RNA was above the limits of quantification in both saline- and camostat-treated hamsters 5 days after cohabitation with a SARS-CoV-2 inoculated hamster. However, intranasal nafamostat-treated hamsters remained RNA negative for the full 7 days of cohabitation. Changes in body weight over the course of the experiment were supportive of a lack of clinical symptomology in nafamostat-treated but not saline- or camostat-treated animals. These data are strongly supportive of the utility of intranasally delivered nafamostat for prevention of SARS-CoV-2 infection and further studies are underway to confirm absence of pulmonary infection and pathological changes.
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5
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Rajoli RKR, Pertinez H, Arshad U, Box H, Tatham L, Curley P, Neary M, Sharp J, Liptrott NJ, Valentijn A, David C, Rannard SP, Aljayyoussi G, Pennington SH, Hill A, Boffito M, Ward SA, Khoo SH, Bray PG, O'Neill PM, Hong WD, Biagini GA, Owen A. Dose prediction for repurposing nitazoxanide in SARS-CoV-2 treatment or chemoprophylaxis. Br J Clin Pharmacol 2021; 87:2078-2088. [PMID: 33085781 PMCID: PMC8056737 DOI: 10.1111/bcp.14619] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/10/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
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.
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Affiliation(s)
- Rajith K. R. Rajoli
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Henry Pertinez
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Usman Arshad
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Helen Box
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Lee Tatham
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Paul Curley
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Megan Neary
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Joanne Sharp
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Neill J. Liptrott
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Anthony Valentijn
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Christopher David
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | | | - Ghaith Aljayyoussi
- Centre for Drugs and Diagnostics, and Department of Tropical Disease BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Shaun H. Pennington
- Centre for Drugs and Diagnostics, and Department of Tropical Disease BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Andrew Hill
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | - Marta Boffito
- Chelsea and Westminster NHS Foundation Trust and St Stephen's AIDS Trust 4th FloorChelsea and Westminster HospitalLondonUK
- Jefferiss Research Trust Laboratories, Department of MedicineImperial CollegeLondonUK
| | - Steve A. Ward
- Centre for Drugs and Diagnostics, and Department of Tropical Disease BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Saye H. Khoo
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
| | | | | | - W. David Hong
- Department of ChemistryUniversity of LiverpoolLiverpoolUK
| | - Giancarlo A. Biagini
- Centre for Drugs and Diagnostics, and Department of Tropical Disease BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Andrew Owen
- Department of Molecular and Clinical Pharmacology, Materials Innovation FactoryUniversity of LiverpoolLiverpoolUK
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6
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Rannard SP, McDonald TO, Owen A. Chasing COVID-19 chemotherapeutics without putting the cart before the horse. Br J Clin Pharmacol 2020; 89:421-423. [PMID: 33217038 PMCID: PMC7753793 DOI: 10.1111/bcp.14575] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 01/02/2023] Open
Affiliation(s)
- Steven P. Rannard
- Department of ChemistryUniversity of LiverpoolLiverpoolUK,Centre of Excellence in Long‐acting Therapeutics (CELT)University of LiverpoolLiverpoolUK
| | - Tom O. McDonald
- Department of ChemistryUniversity of LiverpoolLiverpoolUK,Centre of Excellence in Long‐acting Therapeutics (CELT)University of LiverpoolLiverpoolUK
| | - Andrew Owen
- Department of Pharmacology and TherapeuticsUniversity of LiverpoolLiverpoolUK,Centre of Excellence in Long‐acting Therapeutics (CELT)University of LiverpoolLiverpoolUK
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7
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Tatham LM, Savage AC, Dwyer A, Siccardi M, Scott T, Vourvahis M, Clark A, Rannard SP, Owen A. Towards a Maraviroc long-acting injectable nanoformulation. Eur J Pharm Biopharm 2019; 138:92-98. [DOI: 10.1016/j.ejpb.2018.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/09/2018] [Accepted: 04/12/2018] [Indexed: 10/17/2022]
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8
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Liptrott NJ, Giardiello M, McDonald TO, Rannard SP, Owen A. Lack of interaction of lopinavir solid drug nanoparticles with cells of the immune system. Nanomedicine (Lond) 2017; 12:2043-2054. [PMID: 28805110 DOI: 10.2217/nnm-2017-0095] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIM We previously demonstrated that solid drug nanoparticles (SDNs) lopinavir (LPV) dispersed into aqueous media display favorable pharmacokinetics. METHODS The impact of LPV SDNs on the function and phenotype of primary human T cells and macrophages (primary sites of HIV replication) was investigated. RESULTS LPV significantly increased IL-1β (ninefold higher than untreated cells; p = 0.045) and TNF-α (sixfold higher than untreated cells; p = 0.018) secretion from monocyte-derived macrophages, whereas LPV SDNs did not elicit these responses at comparable drug concentrations. LPV SDNs were demonstrated to be immunologically inert to human T cells and monocyte-derived macrophages. CONCLUSION The LPV SDN was demonstrated to exhibit comparable, or favorable behavior compared with an LPV aqueous solution in the employed biocompatibility assessments.
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Affiliation(s)
- Neill J Liptrott
- Department of Molecular & Clinical Pharmacology, Institute of Translational Medicine, the University of Liverpool, Liverpool, UK.,European Nanomedicine Characterisation Laboratory, Institute of Translational Medicine, the University of Liverpool, Liverpool, UK
| | - Marco Giardiello
- Department of Chemistry, the University of Liverpool, Liverpool, UK
| | - Tom O McDonald
- Department of Chemistry, the University of Liverpool, Liverpool, UK
| | - Steven P Rannard
- European Nanomedicine Characterisation Laboratory, Institute of Translational Medicine, the University of Liverpool, Liverpool, UK.,Department of Chemistry, the University of Liverpool, Liverpool, UK
| | - Andrew Owen
- Department of Molecular & Clinical Pharmacology, Institute of Translational Medicine, the University of Liverpool, Liverpool, UK.,European Nanomedicine Characterisation Laboratory, Institute of Translational Medicine, the University of Liverpool, Liverpool, UK
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9
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Jackson AW, Chandrasekharan P, Shi J, Rannard SP, Liu Q, Yang CT, He T. Synthesis and in vivo magnetic resonance imaging evaluation of biocompatible branched copolymer nanocontrast agents. Int J Nanomedicine 2015; 10:5895-907. [PMID: 26425088 PMCID: PMC4583124 DOI: 10.2147/ijn.s88764] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Branched copolymer nanoparticles (Dh =20–35 nm) possessing 1,4,7, 10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid macrocycles within their cores have been synthesized and applied as magnetic resonance imaging (MRI) nanosized contrast agents in vivo. These nanoparticles have been generated from novel functional monomers via reversible addition–fragmentation chain transfer polymerization. The process is very robust and synthetically straightforward. Chelation with gadolinium and preliminary in vivo experiments have demonstrated promising characteristics as MRI contrast agents with prolonged blood retention time, good biocompatibility, and an intravascular distribution. The ability of these nanoparticles to perfuse and passively target tumor cells through the enhanced permeability and retention effect is also demonstrated. These novel highly functional nanoparticle platforms have succinimidyl ester-activated benzoate functionalities within their corona, which make them suitable for future peptide conjugation and subsequent active cell-targeted MRI or the conjugation of fluorophores for bimodal imaging. We have also demonstrated that these branched copolymer nanoparticles are able to noncovalently encapsulate hydrophobic guest molecules, which could allow simultaneous bioimaging and drug delivery.
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Affiliation(s)
- Alexander W Jackson
- Institute of Chemical and Engineering Sciences (ICES), National University of Singapore, Singapore
| | - Prashant Chandrasekharan
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science Technology and Research(A STAR), National University of Singapore, Singapore
| | - Jian Shi
- Department of Biological Science, National University of Singapore, Singapore
| | - Steven P Rannard
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Quan Liu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Chang-Tong Yang
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Tao He
- Institute of Chemical and Engineering Sciences (ICES), National University of Singapore, Singapore ; School of Chemistryand Chemical Engineering, HeFei University of Technology, Anhui, People's Republic of China
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10
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Martin P, Giardiello M, McDonald TO, Smith D, Siccardi M, Rannard SP, Owen A. Augmented Inhibition of CYP3A4 in Human Primary Hepatocytes by Ritonavir Solid Drug Nanoparticles. Mol Pharm 2015; 12:3556-68. [DOI: 10.1021/acs.molpharmaceut.5b00204] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Philip Martin
- Department
of Molecular and Clinical Pharmacology, University of Liverpool, Block H, 70 Pembroke Place, Liverpool L69 3GF, U.K
| | - Marco Giardiello
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 3BX, U.K
| | - Tom O. McDonald
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 3BX, U.K
| | - Darren Smith
- Department
of Applied Sciences, University of Northumbria at Newcastle, Ellison
Building, Newcastle NE1
8ST, U.K
| | - Marco Siccardi
- Department
of Molecular and Clinical Pharmacology, University of Liverpool, Block H, 70 Pembroke Place, Liverpool L69 3GF, U.K
| | - Steven P. Rannard
- Department
of Chemistry, University of Liverpool, Crown Street, Liverpool L69 3BX, U.K
| | - Andrew Owen
- Department
of Molecular and Clinical Pharmacology, University of Liverpool, Block H, 70 Pembroke Place, Liverpool L69 3GF, U.K
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11
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Hatton FL, Tatham LM, Tidbury LR, Chambon P, He T, Owen A, Rannard SP. Hyperbranched polydendrons: a new nanomaterials platform with tuneable permeation through model gut epithelium. Chem Sci 2015; 6:326-334. [PMID: 28966760 PMCID: PMC5586204 DOI: 10.1039/c4sc02889a] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 10/03/2014] [Indexed: 12/29/2022] Open
Abstract
The development of nanomaterials for advanced therapies requires the formation of versatile platforms that may be tuned to maximize beneficial attributes and minimize unwanted negative behaviour. Additionally, the optimum route of administration is a key consideration of any new treatment and much work has been focused on direct injection into the systemic circulation rather than oral delivery. Here we describe a new approach to polymeric nanoparticle design and present initial results showing the potential for tuneable permeation through a gut epithelium model. Through the use of mixed initiators and branched vinyl polymerization, a series of systematically varying branched polymers have been synthesized and nanoprecipitated. The surprisingly uniform structures have undergone preliminary pharmacological evaluation to establish low cytotoxicity and enhanced permeation through model intestinal epithelial cells. This presents potential opportunities for future developments that may allow oral dosing to result in circulating polymeric nanoparticles; behaviour that may prove clinically desirable to many non-terminal or chronic diseases that utilise nanomedicines but wish to avoid regular or repeated intravenous administration.
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Affiliation(s)
- Fiona L Hatton
- Department of Chemistry , University of Liverpool , Crown Street , L69 7ZD , UK .
| | - Lee M Tatham
- Department of Molecular and Clinical Pharmacology , University of Liverpool , Block H, 70 Pembroke Place , Liverpool L69 3GF , UK
| | - Louise R Tidbury
- Department of Molecular and Clinical Pharmacology , University of Liverpool , Block H, 70 Pembroke Place , Liverpool L69 3GF , UK
| | - Pierre Chambon
- Department of Chemistry , University of Liverpool , Crown Street , L69 7ZD , UK .
| | - Tao He
- Institute of Chemical and Engineering Sciences , Agency for Science , Technology and Research (ASTAR) , 1, Pesek Road, Jurong Island , 627833 , Singapore
| | - Andrew Owen
- Department of Molecular and Clinical Pharmacology , University of Liverpool , Block H, 70 Pembroke Place , Liverpool L69 3GF , UK
| | - Steven P Rannard
- Department of Chemistry , University of Liverpool , Crown Street , L69 7ZD , UK .
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12
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Auty SER, Andrén OCJ, Y. Hern F, Malkoch M, Rannard SP. ‘One-pot’ sequential deprotection/functionalisation of linear-dendritic hybrid polymers using a xanthate mediated thiol/Michael addition. Polym Chem 2015. [DOI: 10.1039/c4py01253d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Xanthate functional dendritic ATRP macroinitiators, synthesised via a new orthogonal strategy, have been used to form a library of linear-dendritic hybrids via one-pot, post polymerisation, deprotection/acrylate Michael addition.
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Affiliation(s)
- Sam E. R. Auty
- Department of Chemistry
- University of Liverpool
- Liverpool L69 7ZD
- UK
| | - Oliver C. J. Andrén
- KTH Royal Institute of Technology
- School of Chemical Engineering
- Department of Fibre and Polymer Technology
- Stockholm
- Sweden
| | - Faye Y. Hern
- Department of Chemistry
- University of Liverpool
- Liverpool L69 7ZD
- UK
| | - Michael Malkoch
- KTH Royal Institute of Technology
- School of Chemical Engineering
- Department of Fibre and Polymer Technology
- Stockholm
- Sweden
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13
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McDonald TO, Giardiello M, Martin P, Siccardi M, Liptrott NJ, Smith D, Roberts P, Curley P, Schipani A, Khoo SH, Long J, Foster AJ, Rannard SP, Owen A. Antiretroviral solid drug nanoparticles with enhanced oral bioavailability: production, characterization, and in vitro-in vivo correlation. Adv Healthc Mater 2014; 3:400-11. [PMID: 23997027 DOI: 10.1002/adhm.201300280] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Indexed: 01/11/2023]
Abstract
Nanomedicine strategies have produced many commercial products. However, no orally dosed HIV nanomedicines are available clinically to patients. Although nanosuspensions of drug particles have demonstrated many benefits, experimentally achieving >25 wt% of drug relative to stabilizers is highly challenging. In this study, the emulsion-templated freeze-drying technique for nanoparticles formation is applied for the first time to optimize a nanodispersion of the leading non-nucleoside reverse transcriptase inhibitor efavirenz, using clinically acceptable polymers and surfactants. Dry monoliths containing solid drug nanoparticles with extremely high drug loading (70 wt% relative to polymer and surfactant stabilizers) are stable for several months and reconstitute in aqueous media to provide nanodispersions with z-average diameters of 300 nm. The solid drug nanoparticles exhibit reduced cytoxicity and increased in vitro transport through model gut epithelium. In vivo studies confirm bioavailability benefits with an approximately four-fold higher pharmacokinetic exposure after oral administration to rodents, and predictive modeling suggests dose reduction with the new formulation may be possible.
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Affiliation(s)
- Tom O. McDonald
- Department of Chemistry; University of Liverpool; Crown Street L69 3BX UK
| | - Marco Giardiello
- Department of Chemistry; University of Liverpool; Crown Street L69 3BX UK
| | - Philip Martin
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Marco Siccardi
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Neill J. Liptrott
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Darren Smith
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Phill Roberts
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Paul Curley
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Alessandro Schipani
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - Saye H. Khoo
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
| | - James Long
- IOTA NanoSolutions Ltd.; Crown Street Liverpool L69 7ZB UK
| | | | - Steven P. Rannard
- Department of Chemistry; University of Liverpool; Crown Street L69 3BX UK
| | - Andrew Owen
- Department of Molecular and Clinical Pharmacology; University of Liverpool; Block H, 70 Pembroke Place Liverpool L69 3GF UK
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14
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Hatton FL, Chambon P, McDonald TO, Owen A, Rannard SP. Hyperbranched polydendrons: a new controlled macromolecular architecture with self-assembly in water and organic solvents. Chem Sci 2014. [DOI: 10.1039/c4sc00360h] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A new macromolecular architecture comprising multiple linear-dendritic hybrid copolymer sub-units is presented – hyperbranched polydendrons. The materials are very high molecular weight and disperse but undergo extremely uniform self-assembly behaviour.
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Affiliation(s)
| | | | | | - Andrew Owen
- Department of Molecular and Clinical Pharmacology
- University of Liverpool
- Liverpool L69 3GF, UK
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15
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Auty SER, Andrén O, Malkoch M, Rannard SP. The first peripherally masked thiol dendrimers: a facile and highly efficient functionalization strategy of polyester dendrimers via one-pot xanthate deprotection/thiol–acrylate Michael addition reactions. Chem Commun (Camb) 2014; 50:6574-7. [DOI: 10.1039/c3cc49704f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the first xanthate surface functional dendrimers which undergo rapid one-pot deprotection to thiols and subsequent acrylate Michael addition .
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Affiliation(s)
- Sam E R Auty
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, UK.
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16
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Martin P, Giardiello M, McDonald TO, Rannard SP, Owen A. Mediation of in Vitro Cytochrome P450 Activity by Common Pharmaceutical Excipients. Mol Pharm 2013; 10:2739-48. [DOI: 10.1021/mp400175n] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Philip Martin
- Department of Molecular
and
Clinical Pharmacology, University of Liverpool, Block H, 70 Pembroke
Place, Liverpool, L69 3GF, U.K
| | - Marco Giardiello
- Department of Chemistry, University
of Liverpool, Crown Street, L69 3BX, U.K
| | - Tom O. McDonald
- Department of Chemistry, University
of Liverpool, Crown Street, L69 3BX, U.K
| | - Steven P. Rannard
- Department of Chemistry, University
of Liverpool, Crown Street, L69 3BX, U.K
- MRC Centre for Drug Safety Science,
University of Liverpool, Liverpool, L69 3GE, U.K
| | - Andrew Owen
- Department of Molecular
and
Clinical Pharmacology, University of Liverpool, Block H, 70 Pembroke
Place, Liverpool, L69 3GF, U.K
- MRC Centre for Drug Safety Science,
University of Liverpool, Liverpool, L69 3GE, U.K
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17
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Zhang H, Wang D, Butler R, Campbell NL, Long J, Tan B, Duncalf DJ, Foster AJ, Hopkinson A, Taylor D, Angus D, Cooper AI, Rannard SP. Formation and enhanced biocidal activity of water-dispersable organic nanoparticles. Nat Nanotechnol 2008; 3:506-511. [PMID: 18685640 DOI: 10.1038/nnano.2008.188] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 06/09/2008] [Indexed: 05/26/2023]
Abstract
Water-insoluble organic compounds are often used in aqueous environments in various pharmaceutical and consumer products. To overcome insolubility, the particles are dispersed in a medium during product formation, but large particles that are formed may affect product performance and safety. Many techniques have been used to produce nanodispersions-dispersions with nanometre-scale dimensions-that have properties similar to solutions. However, making nanodispersions requires complex processing, and it is difficult to achieve stability over long periods. Here we report a generic method for producing organic nanoparticles with a combination of modified emulsion-templating and freeze-drying. The dry powder composites formed using this method are highly porous, stable and form nanodispersions upon simple addition of water. Aqueous nanodispersions of Triclosan (a commercial antimicrobial agent) produced with this approach show greater activity than organic/aqueous solutions of Triclosan.
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18
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Weaver JVM, Williams RT, Royles BJL, Findlay PH, Cooper AI, Rannard SP. pH-Responsive branched polymernanoparticles. Soft Matter 2008; 4:985-992. [PMID: 32907131 DOI: 10.1039/b718118c] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We describe a new one-pot, single-step route for the preparation of pH-responsive branched polymer nanoparticles. These polymers, which are based on the pH-responsive monomer 2-(diethylamino)ethyl methacrylate (DEA) and hydrophilic macromonomer poly(ethyleneglycol) methacrylate (PEGMA), are synthesised using a modified conventional free-radical polymerisation. Consequently, their preparation is generic, scaleable and tolerant of functionality. In aqueous solution the branched copolymers form core-shell structures at basic pH and on reducing the solution pH they become hydrated and swell, displaying similar characteristics to those of pH-responsive shell cross-linked micelles and microgels. We demonstrate good control over the hydrodynamic particle size, polymer chain-end, and the uptake and release of a model hydrophobe and also the ability to tune the apparent pKa of the DEA residues by varying the degree of branching. These results augur well for commercially viable tunable release applications.
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Affiliation(s)
- Jonathan V M Weaver
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UKL69 7ZD.
| | - Richard T Williams
- Fujifilm Imaging Colorants Ltd, Hexagon Tower, Blackley, Manchester, UKM9 8ZS
| | | | - Paul H Findlay
- Hydra Polymers Limited, MerseyBio, Crown Street, Liverpool, UKL69 7ZB
| | - Andrew I Cooper
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UKL69 7ZD.
| | - Steven P Rannard
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UKL69 7ZD.
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19
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Jana S, Rannard SP, Cooper AI. Structure–LCST relationships for end-functionalized water-soluble polymers: an “accelerated” approach to phase behaviour studies. Chem Commun (Camb) 2007:2962-4. [PMID: 17622445 DOI: 10.1039/b702067h] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel "high throughput" technique for LCST measurement was developed which is able to identify the effect of subtle changes in end group composition on the aqueous phase behaviour of water-soluble poly(2-(dimethylamino)ethyl methacrylate).
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Affiliation(s)
- Satyasankar Jana
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UK L69 3BX
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20
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Rannard SP, Rogers SH, Hunter R. Synthesis of well-defined Locust Bean Gum-graft-copolymers using ambient aqueous atom transfer radical polymerisation. Chem Commun (Camb) 2007:362-4. [PMID: 17220971 DOI: 10.1039/b616148k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first atom transfer radical graft copolymerisation at ambient temperature in water from a soluble polysaccharide is demonstrated for a range of monomer types.
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Affiliation(s)
- Steven P Rannard
- Unilever Research and Development Port Sunlight Laboratories, Quarry Road East, Bebington, Wirral, UK CH63 3JW.
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21
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Wood MR, Duncalf DJ, Findlay P, Rannard SP, Perrier S. Investigation of the Experimental Factors Affecting the Trithiocarbonate-Mediated RAFT Polymerization of Methyl Acrylate. Aust J Chem 2007. [DOI: 10.1071/ch07171] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The reversible addition–fragmentation chain transfer polymerization of acrylates, using methyl acrylate (MA) as a monomer model, mediated by a trithiocarbonate was tested under several conditions where the experimental parameters were systematically altered. The most significant parameter in controlling the rate and control of the polymerization was found to be the ratio of chain transfer agent (CTA) to initiator. Decreasing this ratio increased the rate of polymerization and had little noticeable effect on the control over molecular weight distribution. A ratio of CTA to initiator of unity was shown to give the best compromise between rate and control of the polymerization. Targeted degrees of polymerization (equivalent to ratios of monomer to CTA) had negligible effect on the rate of polymerization and polydispersity index (PDI). Performing the polymerization in the presence of solvent (up to 41.2% (w/w) in toluene) had no negative effect on the rate of polymerization. Indeed, marginally higher conversions and lower PDIs than for bulk polymerization were achieved for similar reaction times. A higher amount of toluene (66.6% (w/w)) induced a lower rate of polymerization, but the evolution of molecular weight and PDI were unaffected. Polymerizations performed in the presence of toluene, N,N′-dimethylformamide, and methyl ethyl ketone showed that solvent polarity and aromaticity had no observable effect on the rate of polymerization and over the control of molecular weight distribution. The optimum conditions for the polymerization of MA, mediated by 2-ethylthiocarbonylsulfanyl-propionic acid ethyl ester at 50°C were found to be [CTA]/[AIBN] = 1/1 and ~40% solvent (w/w).
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22
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Bannister I, Billingham NC, Armes SP, Rannard SP, Findlay P. Development of Branching in Living Radical Copolymerization of Vinyl and Divinyl Monomers. Macromolecules 2006. [DOI: 10.1021/ma061811b] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Iveta Bannister
- Department of Chemistry, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QJ, UK; Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK; and Unilever Research Centre, Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, UK
| | - Norman C. Billingham
- Department of Chemistry, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QJ, UK; Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK; and Unilever Research Centre, Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, UK
| | - Steven P. Armes
- Department of Chemistry, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QJ, UK; Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK; and Unilever Research Centre, Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, UK
| | - Steven P. Rannard
- Department of Chemistry, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QJ, UK; Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK; and Unilever Research Centre, Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, UK
| | - Paul Findlay
- Department of Chemistry, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QJ, UK; Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK; and Unilever Research Centre, Port Sunlight, Quarry Road East, Bebington, Wirral, CH63 3JW, UK
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23
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Wood MR, Duncalf DJ, Rannard SP, Perrier S. Selective One-Pot Synthesis of Trithiocarbonates, Xanthates, and Dithiocarbamates for Use in RAFT/MADIX Living Radical Polymerizations. Org Lett 2006; 8:553-6. [PMID: 16468709 DOI: 10.1021/ol0525617] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] We report a facile route for the production of chain transfer agents for reversible addition fragmentation chain transfer (RAFT) and macromolecular design via the interchange of xanthates (MADIX) polymerizations, via a one-pot reaction. 1,1'-Thiocarbonyl diimidazole (TCDI) undergoes controlled monosubstitution when reacted with secondary thiols or alcohols. The intermediate S/O-esters of imidazole-N-thionocarboxylic acid react efficiently with a range of primary thiols, alcohols, and amines to form asymmetrical dithiocarbonates, trithiocarbonates, and dithiocarbamates, respectively. The synthesis provides a facile approach to the controlled radical polymerization of vinyl monomers through the reversible addition-fragmentation chain transfer (RAFT) mechanism.
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Affiliation(s)
- Murray R Wood
- Department of Colour and Polymer Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, England
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24
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Hussain I, Graham S, Wang Z, Tan B, Sherrington DC, Rannard SP, Cooper AI, Brust M. Size-Controlled Synthesis of Near-Monodisperse Gold Nanoparticles in the 1−4 nm Range Using Polymeric Stabilizers. J Am Chem Soc 2005; 127:16398-9. [PMID: 16305218 DOI: 10.1021/ja055321v] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report here a simple one-step protocol for the preparation of near-monodisperse gold hydrosols in the small size regime (<5 nm). The particle size can be controlled by varying the concentration of the stabilizing polymer, which can be readily displaced by thiol ligands to yield monolayer protected clusters of the usual type.
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Affiliation(s)
- Irshad Hussain
- Centre for Nanoscale Science, Department of Chemistry, The University of Liverpool, Crown Street, Liverpool L69 7ZD, United Kingdom
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25
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Zhang H, Hussain I, Brust M, Butler MF, Rannard SP, Cooper AI. Aligned two- and three-dimensional structures by directional freezing of polymers and nanoparticles. Nat Mater 2005; 4:787-93. [PMID: 16184171 DOI: 10.1038/nmat1487] [Citation(s) in RCA: 412] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 08/03/2005] [Indexed: 05/04/2023]
Abstract
The preparation of materials with aligned porosity in the micrometre range is of technological importance for a wide range of applications in organic electronics, microfluidics, molecular filtration and biomaterials. Here, we demonstrate a generic method for the preparation of aligned materials using polymers, nanoparticles or mixtures of these components as building blocks. Directional freezing is used to align the structural elements, either in the form of three-dimensional porous structures or as two-dimensional oriented surface patterns. This simple technique can be used to generate a diverse array of complex structures such as polymer-inorganic nanocomposites, aligned gold microwires and microwire networks, porous composite microfibres and biaxially aligned composite networks. The process does not involve any chemical reaction, thus avoiding potential complications associated with by-products or purification procedures.
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Affiliation(s)
- Haifei Zhang
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK
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26
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Pilon LN, Armes SP, Findlay P, Rannard SP. Synthesis and characterization of shell cross-linked micelles with hydroxy-functional coronas: a pragmatic alternative to dendrimers? Langmuir 2005; 21:3808-3813. [PMID: 15835941 DOI: 10.1021/la047046g] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Shell cross-linked (SCL) micelles with hydroxy-functional coronas have been constructed in aqueous solution by exploiting the micellar self-assembly behavior of a new thermoresponsive ABC triblock copolymer. This copolymer was prepared via atom transfer radical polymerization in a convenient one-pot synthesis and comprised a thermoresponsive core-forming poly(propylene oxide) (PPO) block, a cross-linkable central poly(2-(dimethylamino)ethyl methacrylate) (DMA) block, and a hydroxy-functional outer block based on poly(glycerol monomethacrylate) (GMA). DMF GPC analysis confirmed a unimodal molecular weight distribution for the PPO-PDMA-PGMA triblock copolymer precursor, with an M(n) of 12 100 and a polydispersity of approximately 1.26. This copolymer dissolved molecularly in aqueous solution at 5 degrees C but formed micelles with hydroxy-functional coronas above a critical micelle temperature of around 12 degrees C, which corresponded closely to the cloud point of the PPO macroinitiator. Cross-linking of the DMA residues using 1,2-bis(2-iodoethoxy)ethane produced SCL micelles that remained intact at 5 degrees C, i.e., below the cloud point of the core-forming PPO block. Dynamic light scattering studies confirmed that the SCL micelle diameter could be varied depending on the temperature employed for cross-linking: smaller, more compact SCL micelles were formed at higher temperatures, as expected. Since cross-linking involved quaternization of the DMA residues, the SCL micelles acquired cationic surface charge as judged by aqueous electrophoresis studies. These cationic SCL micelles were adsorbed onto near-monodisperse anionic silica sols, which were used as a model colloidal substrate. Thermogravimetric analyses indicated a SCL micelle mass loading of 2.5-4.4%, depending on the silica sol diameter and the initial micelle concentration. Aqueous electrophoresis measurements confirmed that surface charge reversal occurred after adsorption of the SCL micelles, and scanning electron microscopy studies revealed a uniform coating of SCL micelles on the silica particles.
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Affiliation(s)
- Laura N Pilon
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
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27
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Weaver JVM, Tang Y, Liu S, Iddon PD, Grigg R, Billingham NC, Armes SP, Hunter R, Rannard SP. Preparation of shell cross-linked micelles by polyelectrolyte complexation. Angew Chem Int Ed Engl 2004; 43:1389-92. [PMID: 15368414 DOI: 10.1002/anie.200352428] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Jonathan V M Weaver
- Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, Brighton, E. Sussex, BN1 9QJ, UK
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28
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Weaver JVM, Tang Y, Liu S, Iddon PD, Grigg R, Billingham NC, Armes SP, Hunter R, Rannard SP. Preparation of Shell Cross-Linked Micelles by Polyelectrolyte Complexation. Angew Chem Int Ed Engl 2004. [DOI: 10.1002/ange.200352428] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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