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Kostyurina E, Allgaier J, Kruteva M, Frielinghaus H, Csiszár A, Förster S, Biehl R. Passive Macromolecular Translocation Mechanism through Lipid Membranes. J Am Chem Soc 2022; 144:15348-15354. [PMID: 35951721 DOI: 10.1021/jacs.2c06659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The translocation of biologically active macromolecules through cell membranes is of vital importance for cells and is a key process for drug delivery. Proteins exploit specific conformational changes in their secondary structure to facilitate membrane translocation. For the large class of biological and synthetic macromolecules, where such conformational adaptions are not possible, guidelines to tailor the structure of monomers and macromolecules to aid membrane translocation and cross-membrane drug delivery would be highly desirable. Here, we use alternating amphiphilic macromolecules to systematically investigate the relation between polarity, polymer chain length, lipid chain length, polymer concentration, and temperature on membrane partition and translocation rate. We employed pulse field gradient NMR and confocal fluorescence microscopy to determine membrane adsorption and desorption rate constants and partitioning coefficients. We find that translocation is a two-step process involving a fast adsorption and membrane insertion process and a slower desorption process. Membrane insertion is a key step that determines the molecular weight, concentration, and temperature dependences. Passive translocation is possible on time scales from minutes to hours. Macromolecules with different adapted hydrophilic/hydrophobic comonomer sequences show the same translocation rate, indicating that common optimized translocation conditions can be realized with a variety of monomer chemical structures. The investigated copolymers are biocompatible, biodegradable, and capable of transporting a hydrophobic payload through the lipid membrane. This detailed understanding of the macromolecular translocation mechanism enables to better tailor the delivery of active agents using macromolecular carriers.
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Affiliation(s)
- Ekaterina Kostyurina
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Jürgen Allgaier
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Margarita Kruteva
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Henrich Frielinghaus
- Jülich Centre for Neutron Science at MLZ, Forschungszentrum Jülich GmbH, 85747 Garching, Germany
| | - Agnes Csiszár
- Institute for Biological Information Processing (IBI-2), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
| | - Stephan Förster
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.,Jülich Centre for Neutron Science at MLZ, Forschungszentrum Jülich GmbH, 85747 Garching, Germany
| | - Ralf Biehl
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany
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Kaneko M, Ishihara K, Nakanishi S. Redox-Active Polymers Connecting Living Microbial Cells to an Extracellular Electrical Circuit. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2001849. [PMID: 32734709 DOI: 10.1002/smll.202001849] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Microbial electrochemical systems in which metabolic electrons in living microbes have been extracted to or injected from an extracellular electrical circuit have attracted considerable attention as environmentally-friendly energy conversion systems. Since general microbes cannot exchange electrons with extracellular solids, electron mediators are needed to connect living cells to an extracellular electrode. Although hydrophobic small molecules that can penetrate cell membranes are commonly used as electron mediators, they cannot be dissolved at high concentrations in aqueous media. The use of hydrophobic mediators in combination with small hydrophilic redox molecules can substantially increase the efficiency of the extracellular electron transfer process, but this method has side effects, in some cases, such as cytotoxicity and environmental pollution. In this Review, recently-developed redox-active polymers are highlighted as a new type of electron mediator that has less cytotoxicity than many conventional electron mediators. Owing to the design flexibility of polymer structures, important parameters that affect electron transport properties, such as redox potential, the balance of hydrophobicity and hydrophilicity, and electron conductivity, can be systematically regulated.
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Affiliation(s)
- Masahiro Kaneko
- Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Kazuhiko Ishihara
- Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Shuji Nakanishi
- Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
- Graduate School of Engineering Science Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531, Japan
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Goda T, Miyahara Y, Ishihara K. Phospholipid-mimicking cell-penetrating polymers: principles and applications. J Mater Chem B 2020; 8:7633-7641. [PMID: 32720672 DOI: 10.1039/d0tb01520b] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Understanding the interactions of eukaryotic cellular membranes with nanomaterials is required to construct efficient and safe nanomedicines and molecular bioengineering. Intracellular uptake of nanocarriers by active endocytosis limits the intracellular distribution to the endosomal compartment, impairing the intended biological actions of the cargo molecules. Nonendocytic intracellular migration is another route for nanomaterials with cationic or amphiphilic properties to evade the barrier function of the lipid bilayer plasma membranes. Direct transport of nanomaterials into cells is efficient, but this may cause cytotoxic or biocidal effects by temporarily disrupting the biological membrane barrier. We have recently discovered that nonendocytic internalization of synthetic amphipathic polymer-based nanoaggregates that mimic the structure of natural phospholipids can occur without inducing cytotoxicity. Analysis using a proton leakage assay indicated that the polymer enters cells by amphiphilicity-induced membrane fusion rather than by transmembrane pore formation. These noncytotoxic cell-penetrating polymers may find applications in drug delivery systems, gene transfection, cell therapies, and biomolecular engineering.
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Affiliation(s)
- Tatsuro Goda
- Department of Biomedical Engineering, Faculty of Science and Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan.
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Goda T, Imaizumi Y, Hatano H, Matsumoto A, Ishihara K, Miyahara Y. Translocation Mechanisms of Cell-Penetrating Polymers Identified by Induced Proton Dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8167-8173. [PMID: 31094202 DOI: 10.1021/acs.langmuir.9b00856] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Unlike the majority of nanomaterials designed for cellular uptake via endocytic pathways, some of the functional nanoparticles and nanospheres directly enter the cytoplasm without overt biomembrane injuries. Previously, we have shown that a water-soluble nanoaggregate composed of amphiphilic random copolymer of 2-methacryloyloxyethyl phosphorylcholine (MPC) and n-butyl methacrylate (BMA), poly(MPC- random-BMA) (PMB), passes live cell membranes in an endocytosis-free manner. Yet, details in its translocation mechanism remain elusive due to the lack of proper analytical methods. To understand this phenomenon experimentally, we elaborated the original pH perturbation assay that is extremely sensitive to the pore formation on cell membranes. The ultimate sensitivity originates from the detection of the smallest indicator H+ (H3O+) passed through the molecularly sized transmembrane pores upon challenge by exogenous reagents. We revealed that water-soluble PMB at the 30 mol % MPC unit (i.e., PMB30W) penetrated into the cytosol of model mammalian cells without any proton leaks, in contrast to conventional cell-penetrating peptides, TAT and R8 as well as the surfactant, Triton X-100. While exposure of PMB30W permeabilized cytoplasmic lactate dehydrogenase out of the cells, indicating the alteration of cell membrane polarity by partitioning of amphiphilic PMB30W into the lipid bilayers. Nevertheless, the biomembrane alterations by PMB30W did not exhibit cytotoxicity. In summary, elucidating translocation mechanisms by proton dynamics will guide the design of nanomaterials with controlled permeabilization to cell membranes for bioengineering applications.
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Affiliation(s)
- Tatsuro Goda
- Institute of Biomaterials and Bioengineering , Tokyo Medical and Dental University (TMDU) , 2-3-10 Kanda-Surugadai , Chiyoda, Tokyo 101-0062 , Japan
- Nano Innovation Institute , Inner Mongolia University for Nationalities , No. 22 HuoLinHe Street , Tongliao , Inner Mongolia 028000 , P. R. China
| | - Yuki Imaizumi
- Institute of Biomaterials and Bioengineering , Tokyo Medical and Dental University (TMDU) , 2-3-10 Kanda-Surugadai , Chiyoda, Tokyo 101-0062 , Japan
| | - Hiroaki Hatano
- Institute of Biomaterials and Bioengineering , Tokyo Medical and Dental University (TMDU) , 2-3-10 Kanda-Surugadai , Chiyoda, Tokyo 101-0062 , Japan
| | - Akira Matsumoto
- Institute of Biomaterials and Bioengineering , Tokyo Medical and Dental University (TMDU) , 2-3-10 Kanda-Surugadai , Chiyoda, Tokyo 101-0062 , Japan
- Kanagawa Institute of Industrial Science and Technology (KISTEC) , 705-1 Shimoimaizumi , Ebina , Kanagawa 243-0435 , Japan
| | | | - Yuji Miyahara
- Institute of Biomaterials and Bioengineering , Tokyo Medical and Dental University (TMDU) , 2-3-10 Kanda-Surugadai , Chiyoda, Tokyo 101-0062 , Japan
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Theerasilp M, Sunintaboon P, Sungkarat W, Nasongkla N. Glucose-installed, SPIO-loaded PEG-b-PCL micelles as MR contrast agents to target prostate cancer cells. APPLIED NANOSCIENCE 2017. [DOI: 10.1007/s13204-017-0610-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Aparicio-Blanco J, Martín-Sabroso C, Torres-Suárez AI. In vitro screening of nanomedicines through the blood brain barrier: A critical review. Biomaterials 2016; 103:229-255. [PMID: 27392291 DOI: 10.1016/j.biomaterials.2016.06.051] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/14/2016] [Accepted: 06/20/2016] [Indexed: 12/16/2022]
Abstract
The blood-brain barrier accounts for the high attrition rate of the treatments of most brain disorders, which therefore remain one of the greatest health-care challenges of the twenty first century. Against this background of hindrance to brain delivery, nanomedicine takes advantage of the assembly at the nanoscale of available biomaterials to provide a delivery platform with potential to raising brain levels of either imaging or therapeutic agents. Nevertheless, to prevent later failure due to ineffective drug levels at the target site, researchers have been endeavoring to develop a battery of in vitro screening procedures that can predict earlier in the drug discovery process the ability of these cutting-edge drug delivery platforms to cross the blood-brain barrier for biomedical purposes. This review provides an in-depth analysis of the currently available in vitro blood-brain barrier models (both cell-based and non-cell-based) with the focus on their suitability for understanding the biological brain distribution of forthcoming nanomedicines. The relationship between experimental factors and underlying physiological assumptions that would ultimately lead to a more predictive capacity of their in vivo performance, and those methods already assayed for the evaluation of the brain distribution of nanomedicines are comprehensively discussed.
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Affiliation(s)
- Juan Aparicio-Blanco
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain
| | - Cristina Martín-Sabroso
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain
| | - Ana-Isabel Torres-Suárez
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain; University Institute of Industrial Pharmacy, Complutense University, 28040, Madrid, Spain.
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Ajiro H, Haramiishi Y, Chanthaset N, Akashi M. Polymer design using trimethylene carbonate with ethylene glycol units for biomedical applications. Polym J 2016. [DOI: 10.1038/pj.2016.35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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8
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Morimoto N, Wakamura M, Muramatsu K, Toita S, Nakayama M, Shoji W, Suzuki M, Winnik FM. Membrane Translocation and Organelle-Selective Delivery Steered by Polymeric Zwitterionic Nanospheres. Biomacromolecules 2016; 17:1523-35. [DOI: 10.1021/acs.biomac.6b00172] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nobuyuki Morimoto
- Department
of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Masaru Wakamura
- Department
of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Kanna Muramatsu
- Department
of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Sayaka Toita
- Department
of Chemistry and Faculty of Pharmacy, University of Montreal, CP6128 Succursale
Center Ville, Montreal, QC H3C 3J7, Canada
| | - Masafumi Nakayama
- Frontier
Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai 980-8578, Japan
| | - Wataru Shoji
- Frontier
Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai 980-8578, Japan
| | - Makoto Suzuki
- Department
of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Françoise M. Winnik
- Department
of Chemistry and Faculty of Pharmacy, University of Montreal, CP6128 Succursale
Center Ville, Montreal, QC H3C 3J7, Canada
- National Institute
for Materials Science, WPI International Center for Materials Nanoarchitectonics
(MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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9
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Dening TJ, Rao S, Thomas N, Prestidge CA. Oral nanomedicine approaches for the treatment of psychiatric illnesses. J Control Release 2015; 223:137-156. [PMID: 26739547 DOI: 10.1016/j.jconrel.2015.12.047] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/23/2015] [Accepted: 12/23/2015] [Indexed: 01/12/2023]
Abstract
Psychiatric illnesses are a leading cause of disability and morbidity globally. However, the preferred orally dosed pharmacological treatment options available for depression, anxiety and schizophrenia are often limited by factors such as low drug aqueous solubility, food effects, high hepatic first-pass metabolism effects and short half-lives. Furthermore, the discovery and development of more effective psychotropic agents has stalled in recent times, with the majority of new drugs reaching the market offering similar efficacy, but suffering from the same oral delivery concerns. As such, the application of nanomedicine formulation approaches to currently available drugs is a viable option for optimizing oral drug delivery and maximizing treatment efficacy. This review focuses on the various delivery challenges encountered by psychotropic drugs, and the ability of nanomedicine formulation strategies to overcome these. Specifically, we critically review proof of concept in vitro and in vivo studies of nanoemulsions/microemulsions, solid lipid nanoparticles, dendrimers, polymeric micelles, nanoparticles of biodegradable polymers and nanosuspensions, and provide new insight into the various mechanisms for improved drug performance. The advantages and limitations of current oral nanomedicine approaches for psychotropic drugs are discussed, which will provide guidance for future research directions and assist in fostering the translation of such delivery systems to the clinical setting. Accordingly, emphasis has been placed on correlating the in vitro/in vivo performance of these nanomedicine approaches with their potential clinical outcomes and benefits for patients.
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Affiliation(s)
- Tahnee J Dening
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Shasha Rao
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Nicky Thomas
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Clive A Prestidge
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5001, Australia.
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11
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Werner M, Sommer JU. Translocation and Induced Permeability of Random Amphiphilic Copolymers Interacting with Lipid Bilayer Membranes. Biomacromolecules 2014; 16:125-35. [DOI: 10.1021/bm501266x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Marco Werner
- Leibniz-Institut für Polymerforschung Dresden, Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität Dresden, Institute of Theoretical Physics, 01069 Dresden, Germany
| | - Jens-Uwe Sommer
- Leibniz-Institut für Polymerforschung Dresden, Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität Dresden, Institute of Theoretical Physics, 01069 Dresden, Germany
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12
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Passeleu-Le Bourdonnec C, Carrupt PA, Scherrmann JM, Martel S. Methodologies to assess drug permeation through the blood-brain barrier for pharmaceutical research. Pharm Res 2013; 30:2729-56. [PMID: 23801086 DOI: 10.1007/s11095-013-1119-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 06/11/2013] [Indexed: 12/21/2022]
Abstract
The drug discovery process for drugs that target the central nervous system suffers from a very high rate of failure due to the presence of the blood-brain barrier, which limits the entry of xenobiotics into the brain. To minimise drug failure at different stages of the drug development process, new methodologies have been developed to understand the absorption, distribution, metabolism, excretion and toxicity (ADMET) profile of drug candidates at early stages of drug development. Additionally, understanding the permeation of drug candidates is also important, particularly for drugs that target the central nervous system. During the first stages of the drug discovery process, in vitro methods that allow for the determination of permeability using high-throughput screening methods are advantageous. For example, performing the parallel artificial membrane permeability assay followed by cell-based models with interesting hits is a useful technique for identifying potential drugs. In silico models also provide interesting information but must be confirmed by in vitro models. Finally, in vivo models, such as in situ brain perfusion, should be studied to reduce a large number of drug candidates to a few lead compounds. This article reviews the different methodologies used in the drug discovery and drug development processes to determine the permeation of drug candidates through the blood-brain barrier.
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Affiliation(s)
- Céline Passeleu-Le Bourdonnec
- School of Pharmaceutical Sciences, University of Geneva University of Lausanne, Quai Ernest Ansermet 30, 1211, Geneva, Switzerland
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Gong J, Chen M, Zheng Y, Wang S, Wang Y. Polymeric micelles drug delivery system in oncology. J Control Release 2012; 159:312-23. [PMID: 22285551 DOI: 10.1016/j.jconrel.2011.12.012] [Citation(s) in RCA: 375] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 12/06/2011] [Indexed: 10/14/2022]
Abstract
Polymeric micelles (PM) system, as an efficient drug carrier, has received growing scientific attention in recent years owing to its solubilization, selective targeting, P-glycoprotein inhibition and altered drug internalization route and subcellular localization properties. Seven PM formulations of anti-tumor drugs being evaluated in clinical trials are reviewed in this paper, in terms of formulation study, in vitro cytotoxicity, in vivo pharmacokinetics, anti-tumor efficacy and safety as well as clinical trials, to shed new light on the discovery of novel PM formulations. In these seven PM formulations, PM system was employed to overcome the issues of low water solubility, high toxicity and (or) multidrug resistance accompanied with the conventional formulation, which greatly hampered their clinical application. Those promising preclinical and clinical results combined with rapid advancement and intense multidisciplinary collaboration enable the extension of the PM system to traditional Chinese medicine, imaging agents, gene and combination agent deliveries as well as some other administration routes, which facilitate the clinical translation of the PM drug delivery system.
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Affiliation(s)
- Jian Gong
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China
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Plapied L, Duhem N, des Rieux A, Préat V. Fate of polymeric nanocarriers for oral drug delivery. Curr Opin Colloid Interface Sci 2011. [DOI: 10.1016/j.cocis.2010.12.005] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Staes E, Absil PA, Lins L, Brasseur R, Deleu M, Lecouturier N, Fievez V, Rieux AD, Mingeot-Leclercq MP, Raussens V, Préat V. Acylated and unacylated ghrelin binding to membranes and to ghrelin receptor: towards a better understanding of the underlying mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:2102-13. [PMID: 20637180 DOI: 10.1016/j.bbamem.2010.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 07/02/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
Abstract
The O-octanoylation of human ghrelin is a natural post-translational modification that enhances its binding to model membranes and could potentially play a central role in ghrelin biological activities. Here, we aimed to clarify the mechanisms that drive ghrelin to the membrane and hence to its receptor that mediates most of its endocrinological effects. As the acylation enhances ghrelin lipophilicity and that ghrelin contains many basic residues, we examined the electrostatic attraction and/or hydrophobic interactions with membranes. Using various liposomes and buffer conditions in binding, zeta potential and isothermal titration calorimetry studies, we found that whereas acylated and unacylated ghrelin were both electrostatically attracted towards the membrane, only acylated ghrelin penetrated into the headgroup and the lipid backbone regions of negatively charged membranes. The O-acylation induced a 120-fold increase in ghrelin local concentration in the membrane. However, acylated ghrelin did not deeply penetrate the membrane nor did it perturb its organisation. Conformational studies by circular dichroism and attenuated total reflection Fourier transformed infrared as well as in silico modelling revealed that both forms of ghrelin mainly adopted the same structure in aqueous, micellar and bilayer environments even though acylated ghrelin structure is slightly more α-helical in a lipid bilayer environment. Altogether our results suggest that membrane acts as a "catalyst" in acylated ghrelin binding to the ghrelin receptor and hence could explain why acylated and unacylated ghrelin are both full agonists of this receptor but in the nanomolar and micromolar range, respectively.
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Affiliation(s)
- Edith Staes
- Université catholique de Louvain, Unité de Pharmacie Galénique, 1200 Brussels, Belgium.
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Roger E, Lagarce F, Garcion E, Benoit JP. Biopharmaceutical parameters to consider in order to alter the fate of nanocarriers after oral delivery. Nanomedicine (Lond) 2010; 5:287-306. [PMID: 20148639 DOI: 10.2217/nnm.09.110] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Oral route is the most common route for the delivery of drugs because it is simple to implement and improves patient compliance and quality of life. However, oral absorption is limited by various physiological barriers and remains a scientific challenge. Nanometric-sized drug delivery systems are being extensively studied and provide promising potential for oral drug delivery. Many different technological solutions have been proposed to enhance the bioavailability or the targeting of drug after oral administration. To reach these goals, it is important to analyze the biopharmaceutical parameters to consider in order to alter the fate of nanocarriers after oral delivery. In the present review, the gastrointestinal barrier and physiological stress factors with regard to nanocarriers' performance or integrity issues are first described. Second, the different characteristics offered by the nanocarriers (size, surface composition and properties mediated by external factors such as ligands) and their effect on the optimal transport of drug into the bloodstream are discussed. Finally, the integrity issue is discussed in function of the expected role of the nanocarriers: bioavailability enhancement or pharmacological targeting.
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Validation of a method for the quantitation of ghrelin and unacylated ghrelin by HPLC. J Pharm Biomed Anal 2009; 51:633-9. [PMID: 19875264 DOI: 10.1016/j.jpba.2009.09.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/22/2009] [Accepted: 09/24/2009] [Indexed: 11/24/2022]
Abstract
An HPLC/UV method was first optimized for the separation and quantitation of human acylated and unacylated (or des-acyl) ghrelin from aqueous solutions. This method was validated by an original approach using accuracy profiles based on tolerance intervals for the total error measurement. The concentration range that achieved adequate accuracy extended from 1.85 to 59.30microM and 1.93 to 61.60microM for acylated and unacylated ghrelin, respectively. Then, optimal temperature, pH and buffer for sample storage were determined. Unacylated ghrelin was found to be stable in all conditions tested. At 37 degrees C acylated ghrelin was stable at pH 4 but unstable at pH 7.4, the main degradation product was unacylated ghrelin. Finally, this validated HPLC/UV method was used to evaluate the binding of acylated and unacylated ghrelin to liposomes.
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Han M, Fu S, Gao JQ, Fang XL. Evaluation of intestinal absorption of ginsenoside Rg1 incorporated in microemulison using parallel artificial membrane permeability assay. Biol Pharm Bull 2009; 32:1069-74. [PMID: 19483317 DOI: 10.1248/bpb.32.1069] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, ginsenoside Rg(1) (Rg(1)), a naturally occurring drug which is hardly absorbed in gastrointestinal (GI) tract due to its high hydrophilicity and low membrane permeability, was incorporated in different compositions of water-in-oil microemulsions (MEs). And parallel artificial membrane permeability assay (PAMPA) that have been mainly utilized for the evaluation of in vitro permeability of early drug candidates was introduced in present study, as well as rat in vivo pharmacokinetics and in vitro permeability measurements, to investigate the effect of w/o ME on Rg(1) absorption. Correlation between various models as mentioned above was further performed to estimate the feasibility of PAMPA in the application of pharmaceutical preparation studies. After being administrated intraduodenally to rats, most of MEs can enhance the intestinal absorption of Rg(1) to various extents with relative bioavailability (F(re)) ranging from 268 to 1270% using drug solution as control. This enhanced absorption of Rg(1) may be related to its increased membrane permeability induced by ME as exhibited in the PAMPA and rat in vitro permeability measurements. Meanwhile, rat in vivo pharmacokinetics-PAMPA correlation (r(2)=0.6082) is significant (p<0.05) for ME, representing a potential prospect for the application of PAMPA in the study of pharmaceutical preparation in some conditions.
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Affiliation(s)
- Min Han
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
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Mathot F, des Rieux A, Ariën A, Schneider YJ, Brewster M, Préat V. Transport mechanisms of mmePEG750P(CL-co-TMC) polymeric micelles across the intestinal barrier. J Control Release 2007; 124:134-43. [DOI: 10.1016/j.jconrel.2007.09.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 08/29/2007] [Accepted: 09/03/2007] [Indexed: 11/30/2022]
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