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Jang BS, Kim E, Gwak MA, Park SA, Park WH. Fabrication and application of drug eluting stent for peripheral artery disease. KOREAN J CHEM ENG 2023. [DOI: 10.1007/s11814-022-1286-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Hassan MM, Hettiarachchi M, Kilani M, Gao X, Sankari A, Boyer C, Mao G. Sustained A1 Adenosine Receptor Antagonist Drug Release from Nanoparticles Functionalized by a Neural Tracing Protein. ACS Chem Neurosci 2021; 12:4438-4448. [PMID: 34672533 DOI: 10.1021/acschemneuro.1c00538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Respiratory dysfunction is a major cause of death in people with spinal cord injury (SCI). A remaining unsolved problem in treating SCI is the intolerable side effects of the drugs to patients. In a significant departure from conventional targeted nanotherapeutics to overcome the blood-brain barrier (BBB), this work pursues a drug-delivery approach that uses neural tracing retrograde transport proteins to bypass the BBB and deliver an adenosine A1 receptor antagonist drug, 1,3-dipropyl-8-cyclopentyl xanthine, exclusively to the respiratory motoneurons in the spinal cord and the brainstem. A single intradiaphragmatic injection at one thousandth of the native drug dosage induces prolonged respiratory recovery in a hemisection animal model. To translate the discovery into new treatments for respiratory dysfunction, we carry out this study to characterize the purity and quality of synthesis, stability, and drug-release properties of the neural tracing protein (wheat germ agglutinin chemically conjugated to horseradish peroxidase)-coupled nanoconjugate. We show that the batch-to-batch particle size and drug dosage variations are less than 10%. We evaluate the nanoconjugate size against the spatial constraints imposed by transsynaptic transport from pre to postsynaptic neurons. We determine that the nanoconjugate formulation is capable of sustained drug release lasting for days at physiologic pH, a prerequisite for long-distance transport of the drug from the diaphragm muscle to the brainstem. We model the drug-release profiles using a first-order reaction model and the Noyes-Whitney diffusion model. We confirm via biological electron microscopy that the nanoconjugate particles do not accumulate in the tissues at the injection site. We define the nanoconjugate storage conditions after monitoring the solution dispersion stability under various conditions for 4 months. This study supports further development of neural tracing protein-enabled nanotherapeutics for treating respiratory problems associated with SCI.
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Affiliation(s)
- Md. Musfizur Hassan
- School of Chemical Engineering, University of New South Wales (UNSW Sydney), Sydney, New South Wales 2052, Australia
| | - Malsha Hettiarachchi
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Mohamed Kilani
- School of Chemical Engineering, University of New South Wales (UNSW Sydney), Sydney, New South Wales 2052, Australia
| | - Xiaohua Gao
- School of Medicine, Wayne State University, Detroit, Michigan 48201, United States
| | - Abdulghani Sankari
- School of Medicine, Wayne State University, Detroit, Michigan 48201, United States
| | - Cyrille Boyer
- School of Chemical Engineering, University of New South Wales (UNSW Sydney), Sydney, New South Wales 2052, Australia
- Australian Centre for Nanomedicine, Sydney, New South Wales 2052, Australia
| | - Guangzhao Mao
- School of Chemical Engineering, University of New South Wales (UNSW Sydney), Sydney, New South Wales 2052, Australia
- Australian Centre for Nanomedicine, Sydney, New South Wales 2052, Australia
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Louzao I, Koch B, Taresco V, Ruiz-Cantu L, Irvine DJ, Roberts CJ, Tuck C, Alexander C, Hague R, Wildman R, Alexander MR. Identification of Novel "Inks" for 3D Printing Using High-Throughput Screening: Bioresorbable Photocurable Polymers for Controlled Drug Delivery. ACS APPLIED MATERIALS & INTERFACES 2018; 10:6841-6848. [PMID: 29322768 DOI: 10.1021/acsami.7b15677] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A robust methodology is presented to identify novel biomaterials suitable for three-dimensional (3D) printing. Currently, the application of additive manufacturing is limited by the availability of functional inks, especially in the area of biomaterials; this is the first time when this method is used to tackle this problem, allowing hundreds of formulations to be readily assessed. Several functional properties, including the release of an antidepressive drug (paroxetine), cytotoxicity, and printability, are screened for 253 new ink formulations in a high-throughput format as well as mechanical properties. The selected candidates with the desirable properties are successfully scaled up using 3D printing into a range of object architectures. A full drug release study and degradability and tensile modulus experiments are presented on a simple architecture to validating the suitability of this methodology to identify printable inks for 3D printing devices with bespoke properties.
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Affiliation(s)
- Iria Louzao
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Britta Koch
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Vincenzo Taresco
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Laura Ruiz-Cantu
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Derek J Irvine
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Clive J Roberts
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Christopher Tuck
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Cameron Alexander
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Richard Hague
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Ricky Wildman
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
| | - Morgan R Alexander
- School of Pharmacy and ‡Faculty of Engineering, University of Nottingham , Nottingham NG7 2RD, U.K
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Scoutaris N, Chai F, Maurel B, Sobocinski J, Zhao M, Moffat JG, Craig DQ, Martel B, Blanchemain N, Douroumis D. Development and Biological Evaluation of Inkjet Printed Drug Coatings on Intravascular Stent. Mol Pharm 2015; 13:125-33. [DOI: 10.1021/acs.molpharmaceut.5b00570] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Nicolaos Scoutaris
- School
of Sciences, Faculty of Engineering and Science, University of Greenwich, Medway, Kent ME4 4TB, U.K
| | - Feng Chai
- Université Lille Nord de France, 590000 Lille, France
- INSERM
U1008, Groupe Recherche Biomatériaux, Faculty of Medicine, Université Lille 2, 59045 Lille, France
| | - Blandine Maurel
- Université Lille Nord de France, 590000 Lille, France
- INSERM
U1008, Groupe Recherche Biomatériaux, Faculty of Medicine, Université Lille 2, 59045 Lille, France
| | - Jonathan Sobocinski
- Université Lille Nord de France, 590000 Lille, France
- INSERM
U1008, Groupe Recherche Biomatériaux, Faculty of Medicine, Université Lille 2, 59045 Lille, France
| | - Min Zhao
- UCL
School of Pharmacy, University College London, 29−39 Brunswick Square, London WC1 N 1AX, U.K
| | - Jonathan G. Moffat
- UCL
School of Pharmacy, University College London, 29−39 Brunswick Square, London WC1 N 1AX, U.K
| | - Duncan Q. Craig
- UCL
School of Pharmacy, University College London, 29−39 Brunswick Square, London WC1 N 1AX, U.K
| | - Bernard Martel
- Université Lille Nord de France, 590000 Lille, France
- UMET
CNRS 8207, Équipe Ingénierie des Systèmes Polymères, University Lille 1, 59655 Villeneuve d’Ascq, France
| | - Nicolas Blanchemain
- Université Lille Nord de France, 590000 Lille, France
- INSERM
U1008, Groupe Recherche Biomatériaux, Faculty of Medicine, Université Lille 2, 59045 Lille, France
| | - Dennis Douroumis
- School
of Sciences, Faculty of Engineering and Science, University of Greenwich, Medway, Kent ME4 4TB, U.K
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Shaikh M, Choudhury NR, Knott R, Garg S. Engineering Stent Based Delivery System for Esophageal Cancer Using Docetaxel. Mol Pharm 2015; 12:2305-17. [PMID: 25936529 DOI: 10.1021/mp500851u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Esophageal cancer patients are often diagnosed as "advanced" cases. These patients are subjected to palliative stenting using self-expanding metallic stents (SEMS) to maintain oral alimentation. Unfortunately, SEMS get reoccluded due to tumor growth, in and over the stent struts. To investigate potential solutions to this problem, docetaxel (DTX) delivery films were prepared using PurSil AL 20 (PUS), which can be used as a covering material for the SEMS. Drug-polymer miscibility and interactions were studied. Bilayer films were prepared by adhering the blank film to the DTX loaded film in order to maintain the unidirectional delivery to the esophagus. In vitro release and the local DTX delivery were studied using in vitro permeation experiments. It was found that DTX and PUS were physically and chemically compatible. The bilayer films exhibited sustained release (>30 days) and minimal DTX permeation through esophageal tissues in vitro. The rate-determining step for the DTX delivery was calculated. It was found that >0.9 fraction of rate control lies with the esophageal tissues, suggesting that DTX delivery can be sustained for longer periods compared to the in vitro release observed. Thus, the bilayer films can be developed as a localized sustained delivery system in combination with the stent.
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Affiliation(s)
- Mohsin Shaikh
- †Centre for Pharmaceutical Innovation and Development (CPID), School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Namita Roy Choudhury
- ‡Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, South Australia 5095, Australia
| | - Robert Knott
- §ANSTO, Locked Bag 2001, Kirrawee, New South Wales 2232, Australia
| | - Sanjay Garg
- †Centre for Pharmaceutical Innovation and Development (CPID), School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
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Abstract
There are nineteen different receptor proteins for adenosine, adenine and uridine nucleotides, and nucleotide sugars, belonging to three families of G protein-coupled adenosine and P2Y receptors, and ionotropic P2X receptors. The majority are functionally expressed in blood vessels, as purinergic receptors in perivascular nerves, smooth muscle and endothelial cells, and roles in regulation of vascular contractility, immune function and growth have been identified. The endogenous ligands for purine receptors, ATP, ADP, UTP, UDP and adenosine, can be released from different cell types within the vasculature, as well as from circulating blood cells, including erythrocytes and platelets. Many purine receptors can be activated by two or more of the endogenous ligands. Further complexity arises because of interconversion between ligands, notably adenosine formation from the metabolism of ATP, leading to complex integrated responses through activation of different subtypes of purine receptors. The enzymes responsible for this conversion, ectonucleotidases, are present on the surface of smooth muscle and endothelial cells, and may be coreleased with neurotransmitters from nerves. What selectivity there is for the actions of purines/pyrimidines comes from differential expression of their receptors within the vasculature. P2X1 receptors mediate the vasocontractile actions of ATP released as a neurotransmitter with noradrenaline (NA) from sympathetic perivascular nerves, and are located on the vascular smooth muscle adjacent to the nerve varicosities, the sites of neurotransmitter release. The relative contribution of ATP and NA as functional cotransmitters varies with species, type and size of blood vessel, neuronal firing pattern, the tone/pressure of the blood vessel, and in ageing and disease. ATP is also a neurotransmitter in non-adrenergic non-cholinergic perivascular nerves and mediates vasorelaxation via smooth muscle P2Y-like receptors. ATP and adenosine can act as neuromodulators, with the most robust evidence being for prejunctional inhibition of neurotransmission via A1 adenosine receptors, but also prejunctional excitation and inhibition of neurotransmission via P2X and P2Y receptors, respectively. P2Y2, P2Y4 and P2Y6 receptors expressed on the vascular smooth muscle are coupled to vasocontraction, and may have a role in pathophysiological conditions, when purines are released from damaged cells, or when there is damage to the protective barrier that is the endothelium. Adenosine is released during hypoxia to increase blood flow via vasodilator A2A and A2B receptors expressed on the endothelium and smooth muscle. ATP is released from endothelial cells during hypoxia and shear stress and can act at P2Y and P2X4 receptors expressed on the endothelium to increase local blood flow. Activation of endothelial purine receptors leads to the release of nitric oxide, hyperpolarising factors and prostacyclin, which inhibits platelet aggregation and thus ensures patent blood flow. Vascular purine receptors also regulate endothelial and smooth muscle growth, and inflammation, and thus are involved in the underlying processes of a number of cardiovascular diseases.
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Affiliation(s)
- Vera Ralevic
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
| | - William R Dunn
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom
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Lu Y, Sturek M, Park K. Microparticles produced by the hydrogel template method for sustained drug delivery. Int J Pharm 2013; 461:258-69. [PMID: 24333903 DOI: 10.1016/j.ijpharm.2013.11.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/17/2013] [Accepted: 11/30/2013] [Indexed: 11/27/2022]
Abstract
Polymeric microparticles have been used widely for sustained drug delivery. Current methods of microparticle production can be improved by making homogeneous particles in size and shape, increasing the drug loading, and controlling the initial burst release. In the current study, the hydrogel template method was used to produce homogeneous poly(lactide-co-glycolide) (PLGA) microparticles and to examine formulation and process-related parameters. Poly(vinyl alcohol) (PVA) was used to make hydrogel templates. The parameters examined include PVA molecular weight, type of PLGA (as characterized by lactide content, inherent viscosity), polymer concentration, drug concentration and composition of solvent system. Three model compounds studied were risperidone, methylprednisolone acetate and paclitaxel. The ability of the hydrogel template method to produce microparticles with good conformity to template was dependent on molecular weight of PVA and viscosity of the PLGA solution. Drug loading and encapsulation efficiency were found to be influenced by PLGA lactide content, polymer concentration and composition of the solvent system. The drug loading and encapsulation efficiency were 28.7% and 82% for risperidone, 31.5% and 90% for methylprednisolone acetate, and 32.2% and 92% for paclitaxel, respectively. For all three drugs, release was sustained for weeks, and the in vitro release profile of risperidone was comparable to that of microparticles prepared using the conventional emulsion method. The hydrogel template method provides a new approach of manipulating microparticles.
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Affiliation(s)
- Ying Lu
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47906, USA
| | - Michael Sturek
- Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kinam Park
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, IN 47906, USA; Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47906, USA.
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8
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Burnstock G, Ralevic V. Purinergic signaling and blood vessels in health and disease. Pharmacol Rev 2013; 66:102-92. [PMID: 24335194 DOI: 10.1124/pr.113.008029] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purinergic signaling plays important roles in control of vascular tone and remodeling. There is dual control of vascular tone by ATP released as a cotransmitter with noradrenaline from perivascular sympathetic nerves to cause vasoconstriction via P2X1 receptors, whereas ATP released from endothelial cells in response to changes in blood flow (producing shear stress) or hypoxia acts on P2X and P2Y receptors on endothelial cells to produce nitric oxide and endothelium-derived hyperpolarizing factor, which dilates vessels. ATP is also released from sensory-motor nerves during antidromic reflex activity to produce relaxation of some blood vessels. In this review, we stress the differences in neural and endothelial factors in purinergic control of different blood vessels. The long-term (trophic) actions of purine and pyrimidine nucleosides and nucleotides in promoting migration and proliferation of both vascular smooth muscle and endothelial cells via P1 and P2Y receptors during angiogenesis and vessel remodeling during restenosis after angioplasty are described. The pathophysiology of blood vessels and therapeutic potential of purinergic agents in diseases, including hypertension, atherosclerosis, ischemia, thrombosis and stroke, diabetes, and migraine, is discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London NW3 2PF, UK; and Department of Pharmacology, The University of Melbourne, Australia.
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Kim CY, XU LIXING, Lee EH, Choa YH. Magnetic Silicone Composites with Uniform Nanoparticle Dispersion as a Biomedical Stent Coating for Hyperthermia. ADVANCES IN POLYMER TECHNOLOGY 2012. [DOI: 10.1002/adv.21314] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Drug eluting stents based on Poly(ethylene carbonate): Optimization of the stent coating process. Eur J Pharm Biopharm 2012; 80:562-70. [DOI: 10.1016/j.ejpb.2011.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 12/11/2011] [Accepted: 12/13/2011] [Indexed: 11/22/2022]
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Yuk SH, Oh KS, Park J, Kim SJ, Kim JH, Kwon IK. Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2012; 13:025005. [PMID: 27877483 PMCID: PMC5090633 DOI: 10.1088/1468-6996/13/2/025005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 04/03/2012] [Accepted: 02/12/2012] [Indexed: 06/06/2023]
Abstract
The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography.
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Affiliation(s)
- Soon Hong Yuk
- College of Pharmacy, Korea University, Jochiwon, Yeongi, Chungnam, 339–700, Korea
| | - Keun Sang Oh
- Biomedical Research Center, Korea Institute of Science and Technology, Seoul, 136–791, Korea
| | - Jinah Park
- College of Pharmacy, Korea University, Jochiwon, Yeongi, Chungnam, 339–700, Korea
| | - Soon-Joong Kim
- Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 136–791, Korea
| | - Jung Ho Kim
- Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 136–791, Korea
| | - Il Keun Kwon
- Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, 136–791, Korea
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Vedantham K, Chaterji S, Kim SW, Park K. Development of a probucol-releasing antithrombogenic drug eluting stent. J Biomed Mater Res B Appl Biomater 2012; 100:1068-77. [PMID: 22331580 DOI: 10.1002/jbm.b.32672] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 10/06/2011] [Accepted: 11/27/2011] [Indexed: 11/10/2022]
Abstract
The success of drug eluting stents (DESs) has been challenged by the manifestation of late stent thrombosis after DES implantation. The incomplete regeneration of the endothelial layer poststenting triggers adverse signaling processes precipitating in thrombosis. Various approaches have been attempted to prevent thrombosis, including the delivery of biological agents, such as estradiol, that promote endothelialization, and the use of natural polymers as coating materials. The underlying challenge has been the inability to release the biological agent in synchronization with the temporal sequence of vascular wound healing in vivo. The natural healing process of the endothelium after an injury starts after a week and may take up to a month in humans. This article presents a novel DES formulation using a hemocompatible polyurethane (PU) matrix to sustain the release of probucol (PB), an endothelial agonist, by exploiting the greater difference in the solubility parameters of PB and PU. This results in the formation of crystalline PB aggregates retarding drug release from PU. The physicochemical properties of PB in PU were confirmed using differential scanning calorimetry and X-ray diffraction. Drug-polymer compatibility was examined using infrared spectral analysis. Also, in vitro studies using primary human aortic endothelial cells resulted in the selection of 5% w/w PB as the optimal dose, to be further tested in vitro and in vivo. This work develops and tests a promising new DES formulation to enable faster endothelial cell proliferation poststenting, potentially minimizing the incidence and severity of thrombotic events after DES implantation.
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Affiliation(s)
- Kumar Vedantham
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA
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Headrick JP, Peart JN, Reichelt ME, Haseler LJ. Adenosine and its receptors in the heart: regulation, retaliation and adaptation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:1413-28. [PMID: 21094127 DOI: 10.1016/j.bbamem.2010.11.016] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/05/2010] [Accepted: 11/07/2010] [Indexed: 10/18/2022]
Abstract
The purine nucleoside adenosine is an important regulator within the cardiovascular system, and throughout the body. Released in response to perturbations in energy state, among other stimuli, local adenosine interacts with 4 adenosine receptor sub-types on constituent cardiac and vascular cells: A(1), A(2A), A(2B), and A(3)ARs. These G-protein coupled receptors mediate varied responses, from modulation of coronary flow, heart rate and contraction, to cardioprotection, inflammatory regulation, and control of cell growth and tissue remodeling. Research also unveils an increasingly complex interplay between members of the adenosine receptor family, and with other receptor groups. Given generally favorable effects of adenosine receptor activity (e.g. improving the balance between myocardial energy utilization and supply, limiting injury and adverse remodeling, suppressing inflammation), the adenosine receptor system is an attractive target for therapeutic manipulation. Cardiovascular adenosine receptor-based therapies are already in place, and trials of new treatments underway. Although the complex interplay between adenosine receptors and other receptors, and their wide distribution and functions, pose challenges to implementation of site/target specific cardiovascular therapy, the potential of adenosinergic pharmacotherapy can be more fully realized with greater understanding of the roles of adenosine receptors under physiological and pathological conditions. This review addresses some of the major known and proposed actions of adenosine and adenosine receptors in the heart and vessels, focusing on the ability of the adenosine receptor system to regulate cell function, retaliate against injurious stressors, and mediate longer-term adaptive responses.
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Affiliation(s)
- John P Headrick
- Griffith Health Institute, Griffith University, Southport QLD, Australia.
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Fu Y, Kao WJ. Drug release kinetics and transport mechanisms of non-degradable and degradable polymeric delivery systems. Expert Opin Drug Deliv 2010; 7:429-44. [PMID: 20331353 DOI: 10.1517/17425241003602259] [Citation(s) in RCA: 731] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
IMPORTANCE OF THE FIELD The advancement in material design and engineering has led to the rapid development of new materials with increasing complexity and functions. Both non-degradable and degradable polymers have found wide applications in the controlled delivery field. Studies on drug release kinetics provide important information into the function of material systems. To elucidate the detailed transport mechanism and the structure-function relationship of a material system, it is critical to bridge the gap between the macroscopic data and the transport behavior at the molecular level. AREAS COVERED IN THIS REVIEW The structure and function information of selected non-degradable and degradable polymers have been collected and summarized from literature published after the 1990s. The release kinetics of selected drug compounds from various material systems is discussed in case studies. Recent progress in the mathematical models based on different transport mechanisms is highlighted. WHAT THE READER WILL GAIN This article aims to provide an overview of structure-function relationships of selected non-degradable and degradable polymers as drug delivery matrices. TAKE HOME MESSAGE Understanding the structure-function relationship of the material system is key to the successful design of a delivery system for a particular application. Moreover, developing complex polymeric matrices requires more robust mathematical models to elucidate the solute transport mechanisms.
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Affiliation(s)
- Yao Fu
- University of Wisconsin-Madison, School of Pharmacy, 777 Highland Avenue, Madison, WI 53705, USA
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