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Lin HL, Mohamed Shukri FN, Yih ES, Sha GH, Jing GS, Jin GW, Hoong CW, Ying CQ, Panda BP, Candasamy M, Bhattamisra SK. Newer therapeutic approaches towards the management of diabetes mellitus: an update. Panminerva Med 2023; 65:362-375. [PMID: 31663302 DOI: 10.23736/s0031-0808.19.03655-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Diabetes mellitus is a chronic metabolic condition characterized by an elevation of blood glucose levels, resulting from defects in insulin secretion, insulin action, or both. The prevalence of the disease has been rapidly rising all over the globe at an alarming rate. Despite advances in the management of diabetes mellitus, it remains a growing epidemic that has become a significant public health burden due to its high healthcare costs and its complications. There is no cure has yet been found for the disease, however, treatment modalities include insulin and antidiabetic agents along with lifestyle modifications are still the mainstay of therapy for diabetes mellitus. The treatment spectrum for the management of diabetes mellitus has rapidly developed in recent years, with new class of therapeutics and expanded indications. This article focused on the emerging therapeutic approaches other than the conventional pharmacological therapies, which include stem cell therapy, gene therapy, siRNA, nanotechnology and theranostics.
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Affiliation(s)
- Heng L Lin
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | | | - Eric S Yih
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Grace H Sha
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Grace S Jing
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Gan W Jin
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Chow W Hoong
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Choong Q Ying
- School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Bibhu P Panda
- Department of Pharmaceutical Technology, School of Pharmacy, Taylor's University, Lakeside Campus, Subang Jaya, Selangor, Malaysia
| | - Mayuren Candasamy
- Department of Life Sciences, School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Subrat K Bhattamisra
- Department of Life Sciences, School of Pharmacy, International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia -
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Cyclo- and Polyphosphazenes for Biomedical Applications. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238117. [PMID: 36500209 PMCID: PMC9736570 DOI: 10.3390/molecules27238117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
Cyclic and polyphosphazenes are extremely interesting and versatile substrates characterized by the presence of -P=N- repeating units. The chlorine atoms on the P atoms in the starting materials can be easily substituted with a variety of organic substituents, thus giving rise to a huge number of new materials for industrial applications. Their properties can be designed considering the number of repetitive units and the nature of the substituent groups, opening up to a number of peculiar properties, including the ability to give rise to supramolecular arrangements. We focused our attention on the extensive scientific literature concerning their biomedical applications: as antimicrobial agents in drug delivery, as immunoadjuvants in tissue engineering, in innovative anticancer therapies, and treatments for cardiovascular diseases. The promising perspectives for their biomedical use rise from the opportunity to combine the benefits of the inorganic backbone and the wide variety of organic side groups that can lead to the formation of nanoparticles, polymersomes, or scaffolds for cell proliferation. In this review, some aspects of the preparation of phosphazene-based systems and their characterization, together with some of the most relevant chemical strategies to obtain biomaterials, have been described.
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Ogueri KS, Ogueri KS, Allcock HR, Laurencin CT. Polyphosphazene polymers: The next generation of biomaterials for regenerative engineering and therapeutic drug delivery. JOURNAL OF VACUUM SCIENCE AND TECHNOLOGY. B, NANOTECHNOLOGY & MICROELECTRONICS : MATERIALS, PROCESSING, MEASUREMENT, & PHENOMENA : JVST B 2020; 38:030801. [PMID: 32309041 PMCID: PMC7156271 DOI: 10.1116/6.0000055] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/23/2020] [Indexed: 05/22/2023]
Abstract
The demand for new biomaterials in several biomedical applications, such as regenerative engineering and drug delivery, has increased over the past two decades due to emerging technological advances in biomedicine. Degradable polymeric biomaterials continue to play a significant role as scaffolding materials and drug devices. Polyphosphazene platform is a subject of broad interest, as it presents an avenue for attaining versatile polymeric materials with excellent structure and property tunability, and high functional diversity. Macromolecular substitution enables the facile attachment of different organic groups and drug molecules to the polyphosphazene backbone for the development of a broad class of materials. These materials are more biocompatible than traditional biomaterials, mixable with other clinically relevant polymers to obtain new materials and exhibit unique erosion with near-neutral degradation products. Hence, polyphosphazene represents the next generation of biomaterials. In this review, the authors systematically discuss the synthetic design, structure-property relationships, and the promising potentials of polyphosphazenes in regenerative engineering and drug delivery.
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Affiliation(s)
| | - Kennedy S Ogueri
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Harry R Allcock
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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Kalhapure RS, Renukuntla J. Thermo- and pH dual responsive polymeric micelles and nanoparticles. Chem Biol Interact 2018; 295:20-37. [DOI: 10.1016/j.cbi.2018.07.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/28/2018] [Accepted: 07/19/2018] [Indexed: 12/31/2022]
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Sivaraj M, Mukherjee A, Mariappan R, Mariadoss AV, Jeyaraj M. Polyorganophosphazene stabilized gold nanoparticles for intracellular drug delivery in breast carcinoma cells. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Mehnath S, Rajan M, Sathishkumar G, Amarnath Praphakar R, Jeyaraj M. Thermoresponsive and pH triggered drug release of cholate functionalized poly(organophosphazene) – polylactic acid co-polymeric nanostructure integrated with ICG. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.11.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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7
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Ullah RS, Wang L, Yu H, Abbasi NM, Akram M, -ul-Abdin Z, Saleem M, Haroon M, Khan RU. Synthesis of polyphosphazenes with different side groups and various tactics for drug delivery. RSC Adv 2017. [DOI: 10.1039/c6ra27103k] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Polyphosphazenes (PPZs) are hybrid polymers comprising a main chain containing nitrogen and phosphorous linked through interchanging single and double bonds, and side chains.
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Affiliation(s)
- Raja Summe Ullah
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Li Wang
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Haojie Yu
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Nasir M. Abbasi
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Muhammad Akram
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Zain -ul-Abdin
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Muhammad Saleem
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Muhammad Haroon
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Rizwan Ullah Khan
- State Key Laboratory of Chemical Engineering
- College of Chemical and Biological Engineering
- Zhejiang University
- Hangzhou 310027
- China
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Burova TV, Grinberg NV, Dubovik AS, Olenichenko EA, Orlov VN, Grinberg VY. Interpolyelectrolyte complexes of lysozyme with short poly[di(carboxylatophenoxy)phosphazene]. Binding energetics and protein conformational stability. POLYMER 2017. [DOI: 10.1016/j.polymer.2016.11.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Akram M, Yu H, Wang L, Khalid H, Abbasi NM, Chen Y, Ren F, Saleem M. Sustained release of hydrophilic drug from polyphosphazenes/poly(methyl methacrylate) based microspheres and their degradation study. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 58:169-79. [PMID: 26478300 DOI: 10.1016/j.msec.2015.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/15/2015] [Accepted: 08/10/2015] [Indexed: 11/18/2022]
Abstract
Drug delivery system is referred as an approach to deliver the therapeutic agents to the target site safely in order to achieve the maximum therapeutic effects. In this perspective, synthesis of three new polyphosphazenes and their blend fabrication system with poly(methyl methacrylate) is described and characterized with (1)H NMR, (31)P NMR, GPC and DSC. Furthermore, these novel blends were used to fabricate microspheres and evaluated for sustain release of hydrophilic drug (aspirin as model drug). Microspheres of the two blends showed excellent encapsulation efficacy (about 93%), controlled burst release (2.3% to 7.93%) and exhibited sustain in vitro drug release (13.44% to 32.77%) up to 218 h. At physiological conditions, the surface degradation of microspheres and diffusion process controlled the drug release sustainability. Furthermore, it was found that the degree of porosity was increased with degradation and the resulting porous network was responsible for water retention inside the microspheres. The percentage water retention was found to be interrelated with degradation time and percentage drug release.
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Affiliation(s)
- Muhammad Akram
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Haojie Yu
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Li Wang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Hamad Khalid
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Nasir M Abbasi
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yongsheng Chen
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Fujie Ren
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Muhammad Saleem
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
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Burova TV, Grinberg NV, Tur DR, Papkov VS, Dubovik AS, Shibanova ED, Bairamashvili DI, Grinberg VY, Khokhlov AR. Ternary interpolyelectrolyte complexes insulin-poly(methylaminophosphazene)-dextran sulfate for oral delivery of insulin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:2273-2281. [PMID: 23339768 DOI: 10.1021/la303860t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ternary interpolyelectrolyte complexes of insulin with biodegradable synthetic cationic polymer, poly(methylaminophosphazene) hydrochloride (PMAP), and dextran sulfate (DS) were investigated by means of turbidimetry, dynamic light scattering, phase analysis, and high-sensitivity differential scanning calorimetry. Formation of ternary insoluble stoichiometric Insulin-PMAP-DS complexes was detected under conditions imitating the human gastric environment (pH 2, 0.15 M NaCl). A complete immobilization of insulin in the complexes was observed in a wide range of the reaction mixture compositions. The ternary complexes were shown to dissolve and dissociate under conditions imitating the human intestinal environment (pH 8.3, 0.15 M NaCl). The products of the complex dissociation were free insulin and soluble binary Insulin-PMAP complexes. The conformational stability of insulin in the soluble complexes of various compositions was investigated by high-sensitivity differential scanning calorimetry. The dependence of the excess denaturation free energy of insulin in these complexes on the PMAP content was obtained. The binding constants of the folded and unfolded forms of insulin to the PMAP polycation were estimated. Proteolysis of insulin involved in the insoluble ternary complexes by pepsin was investigated under physiological conditions. It was found that the complexes ensure an almost 100% protection of insulin against proteolytic degradation. The obtained results provide a perspective basis for development of oral insulin preparations.
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Affiliation(s)
- Tatiana V Burova
- AN Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russian Federation.
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Teasdale I, Brüggemann O. Polyphosphazenes: Multifunctional, Biodegradable Vehicles for Drug and Gene Delivery. Polymers (Basel) 2013; 5:161-187. [PMID: 24729871 PMCID: PMC3982046 DOI: 10.3390/polym5010161] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Poly[(organo)phosphazenes] are a unique class of extremely versatile polymers with a range of applications including tissue engineering and drug delivery, as hydrogels, shape memory polymers and as stimuli responsive materials. This review aims to divulge the basic principles of designing polyphosphazenes for drug and gene delivery and portray the huge potential of these extremely versatile materials for such applications. Polyphosphazenes offer a number of distinct advantages as carriers for bioconjugates; alongside their completely degradable backbone, to non-toxic degradation products, they possess an inherently and uniquely high functionality and, thanks to recent advances in their polymer chemistry, can be prepared with controlled molecular weights and narrow polydispersities, as well as self-assembled supra-molecular structures. Importantly, the rate of degradation/hydrolysis of the polymers can be carefully tuned to suit the desired application. In this review we detail the recent developments in the chemistry of polyphosphazenes, relevant to drug and gene delivery and describe recent investigations into their application in this field.
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Affiliation(s)
- Ian Teasdale
- Institute of Polymer Chemistry, Johannes Kepler University, 4060, Leonding, Austria;
| | - Oliver Brüggemann
- Institute of Polymer Chemistry, Johannes Kepler University, 4060, Leonding, Austria;
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Tomar L, Tyagi C, Kumar M, Kumar P, Singh H, Choonara YE, Pillay V. In vivo evaluation of a conjugated poly(lactide-ethylene glycol) nanoparticle depot formulation for prolonged insulin delivery in the diabetic rabbit model. Int J Nanomedicine 2013; 8:505-20. [PMID: 23429428 PMCID: PMC3575164 DOI: 10.2147/ijn.s38011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Indexed: 11/23/2022] Open
Abstract
Poly(ethylene glycol) (PEG) and polylactic acid (PLA)-based copolymeric nanoparticles were synthesized and investigated as a carrier for prolonged delivery of insulin via the parenteral route. Insulin loading was simultaneously achieved with particle synthesis using a double emulsion solvent evaporation technique, and the effect of varied PEG chain lengths on particle size and insulin loading efficiency was determined. The synthesized copolymer and nanoparticles were analyzed by standard polymer characterization techniques of gel permeation chromatography, dynamic light scattering, nuclear magnetic resonance, and transmission electron microscopy. In vitro insulin release studies performed under simulated conditions provided a near zero-order release pattern up to 10 days. In vivo animal studies were undertaken with varied insulin loads of nanoparticles administered subcutaneously to fed diabetic rabbits and, of all doses administered, nanoparticles containing 50 IU of insulin load per kg body weight controlled the blood glucose level within the physiologically normal range of 90-140 mg/dL, and had a prolonged effect for more than 7 days. Histopathological evaluation of tissue samples from the site of injection showed no signs of inflammation or aggregation, and established the nontoxic nature of the prepared copolymeric nanoparticles. Further, the reaction profiles for PLA-COOH and NH(2)-PEGDA-NH(2) were elucidated using molecular mechanics energy relationships in vacuum and in a solvated system by exploring the spatial disposition of various concentrations of polymers with respect to each other. Incorporation of insulin within the polymeric matrix was modeled using Connolly molecular surfaces. The computational results corroborated the experimental and analytical data. The ability to control blood glucose levels effectively coupled with the nontoxic behavior of the nanoparticles indicates that these nanoparticles are a potential candidate for insulin delivery.
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Affiliation(s)
- Lomas Tomar
- University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, Johannesburg, Gauteng, South Africa
- Centre for Biomedical Engineering, Indian Institute of Technology, Delhi, India
| | - Charu Tyagi
- University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, Johannesburg, Gauteng, South Africa
- VSPG College, Chaudhary Charan Singh University, Meerut, India
| | - Manoj Kumar
- Centre for Biomedical Engineering, Indian Institute of Technology, Delhi, India
| | - Pradeep Kumar
- University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, Johannesburg, Gauteng, South Africa
| | - Harpal Singh
- Centre for Biomedical Engineering, Indian Institute of Technology, Delhi, India
| | - Yahya E Choonara
- University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, Johannesburg, Gauteng, South Africa
| | - Viness Pillay
- University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, Johannesburg, Gauteng, South Africa
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Nazar H, Caliceti P, Carpenter B, El-Mallah AI, Fatouros DG, Roldo M, van der Merwe SM, Tsibouklis J. A once-a-day dosage form for the delivery of insulin through the nasal route: in vitro assessment and in vivo evaluation. Biomater Sci 2013; 1:306-314. [DOI: 10.1039/c2bm00132b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kroger JL, Fried JR. Molecular Simulations of Polyphosphazenes for Biomedical Applications. J Inorg Organomet Polym Mater 2012. [DOI: 10.1007/s10904-012-9706-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Li X, Li Z, Jing Y, Bing B, Li B. Fluorescent organic nanoparticles self-assembled from hexa[p-(carbonyl glycin methyl ester) phenoxy] cyclotriphosphazene in solution. J Colloid Interface Sci 2012; 375:41-9. [DOI: 10.1016/j.jcis.2012.02.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 02/07/2012] [Accepted: 02/11/2012] [Indexed: 11/28/2022]
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Gudasi KB, Vadavi RS, Sreedhar B, Sairam M, Shelke NB, Mallikarjuna NN, Kulkarni PV, Aminahbavi TM. Synthesis and characterization of some organopolyphosphazenes and their controlled-release characteristics. Des Monomers Polym 2012. [DOI: 10.1163/156855507780949227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- K. B. Gudasi
- a Department of Chemistry, Karnatak University, Dharwad 580 003, India
| | - R. S. Vadavi
- b Department of Chemistry, Karnatak University, Dharwad 580 003, India
| | - B. Sreedhar
- c Thermal Analysis Center, Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - M. Sairam
- d Center of Excellence in Polymer Science, Karnatak University, Dharwad 580 003, India
| | - N. B. Shelke
- e Center of Excellence in Polymer Science, Karnatak University, Dharwad 580 003, India
| | - N. N. Mallikarjuna
- f University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9058, USA
| | - P. V. Kulkarni
- g University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9058, USA
| | - T. M. Aminahbavi
- h Center of Excellence in Polymer Science, Karnatak University, Dharwad 580 003, India
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Severino P, Santana MHA, Malmonge SM, Souto EB. Polímeros usados como sistemas de transporte de princípios ativos. POLIMEROS 2011. [DOI: 10.1590/s0104-14282011005000061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Os diferentes sistemas de transporte têm evidenciado potencial terapêutico para uma grande variedade de princípios ativos, satisfazendo vários requisitos, como a prevenção da sua eliminação rápida do organismo, a redução da sua toxicidade sistêmica, a estabilização e a otimização do seu metabolismo, e o direcionamento específico ao local alvo e os mecanismos de defesa. No entanto, têm sido reconhecidos vários outros desafios associados à liberação específica do princípio ativo ao local alvo, pelo que, para ultrapassar os obstáculos químicos e biológicos, a seleção do polímero utilizado para a preparação do sistema de transporte é de importância crucial. O presente trabalho apresenta um relato sobre os principais polímeros naturais e sintéticos utilizados para a preparação de sistemas de transporte de princípios ativos in vivo.
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Sheshala R, Peh KK, Darwis Y. Preparation, characterization, and in vivo evaluation of insulin-loaded PLA-PEG microspheres for controlled parenteral drug delivery. Drug Dev Ind Pharm 2010; 35:1364-74. [PMID: 19832637 DOI: 10.3109/03639040902939213] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIM The aim of this study was to prepare insulin-loaded poly(lactic acid)-polyethylene glycol microspheres that could control insulin release at least for 1 week and evaluate their in vivo performance in a streptozotocin-induced diabetic rat model. METHODS The microspheres were prepared using a water-in-oil-in-water double emulsion solvent evaporation technique. Different formulation variables influencing the yield, particle size, entrapment efficiency, and in vitro release profiles were investigated. The pharmacokinetic study of optimized formulation was performed with single dose in comparison with multiple dose of Humulin 30/70 as a reference product in streptozotocin-induced diabetic rats. RESULTS The optimized formulation of insulin microspheres was nonporous, smooth-surfaced, and spherical in structure under scanning electron microscope with a mean particle size of 3.07 microm and entrapment efficiency of 42.74% of the theoretical amount incorporated. The in vitro insulin release profiles was characterized by a bimodal behavior with an initial burst release because of the insulin adsorbed on the microsphere surface, followed by slower and continuous release corresponding to the insulin entrapped in polymer matrix. CONCLUSIONS The optimized formulation and reference were comparable in the extent of absorption. Consequently, these microspheres can be proposed as new controlled parenteral delivery system.
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Affiliation(s)
- Ravi Sheshala
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia.
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Yang Y, Zhang Z, Chen L, Gu W, Li Y. Urocanic Acid Improves Transfection Efficiency of Polyphosphazene with Primary Amino Groups for Gene Delivery. Bioconjug Chem 2010; 21:419-26. [DOI: 10.1021/bc900267g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yongxin Yang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhiwen Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Lingli Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Wangwen Gu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yaping Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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Sohier J, Moroni L, van Blitterswijk C, de Groot K, Bezemer JM. Critical factors in the design of growth factor releasing scaffolds for cartilage tissue engineering. Expert Opin Drug Deliv 2008; 5:543-66. [PMID: 18491981 DOI: 10.1517/17425247.5.5.543] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Trauma or degenerative diseases of the joints are common clinical problems resulting in high morbidity. Although various orthopedic treatments have been developed and evaluated, the low repair capacities of articular cartilage renders functional results unsatisfactory in the long term. Over the last decade, a different approach (tissue engineering) has emerged that aims not only to repair impaired cartilage, but also to fully regenerate it, by combining cells, biomaterials mimicking extracellular matrix (scaffolds) and regulatory signals. The latter is of high importance as growth factors have the potency to induce, support or enhance the growth and differentiation of various cell types towards the chondrogenic lineage. Therefore, the controlled release of different growth factors from scaffolds appears to have great potential to orchestrate tissue repair effectively. OBJECTIVE This review aims to highlight considerations and limitations of the design, materials and processing methods available to create scaffolds, in relation to the suitability to incorporate and release growth factors in a safe and defined manner. Furthermore, the current state of the art of signalling molecules release from scaffolds and the impact on cartilage regeneration in vitro and in vivo is reported and critically discussed. METHODS The strict aspects of biomaterials, scaffolds and growth factor release from scaffolds for cartilage tissue engineering applications are considered. CONCLUSION Engineering defined scaffolds that deliver growth factors in a controlled way is a task seldom attained. If growth factor delivery appears to be beneficial overall, the optimal delivery conditions for cartilage reconstruction should be more thoroughly investigated.
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Affiliation(s)
- J Sohier
- Laboratory for osteo-articular and dental tissue engineering (LIOAD), Faculté de chirurgie dentaire de Nantes, Inserm U791, 1 Place Alexis Ricordeau, 44042 Nantes Cedex 1, France.
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Moroni L, de Wijn JR, van Blitterswijk CA. Integrating novel technologies to fabricate smart scaffolds. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2008; 19:543-72. [PMID: 18419938 DOI: 10.1163/156856208784089571] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Tissue engineering aims at restoring or regenerating a damaged tissue by combining cells, derived from a patient biopsy, with a 3D porous matrix functioning as a scaffold. After isolation and eventual in vitro expansion, cells are seeded on the 3D scaffolds and implanted directly or at a later stage in the patient's body. 3D scaffolds need to satisfy a number of requirements: (i) biocompatibility, (ii) biodegradability and/or bioresorbability, (iii) suitable mechanical properties, (iv) adequate physicochemical properties to direct cell-material interactions matching the tissue to be replaced and (v) ease in regaining the original shape of the damaged tissue and the integration with the surrounding environment. Still, it appears to be a challenge to satisfy all the aforementioned requisites with the biomaterials and the scaffold fabrication technologies nowadays available. 3D scaffolds can be fabricated with various techniques, among which rapid prototyping and electrospinning seem to be the most promising. Rapid prototyping technologies allow manufacturing scaffolds with a controlled, completely accessible pore network--determinant for nutrient supply and diffusion--in a CAD/CAM fashion. Electrospinning (ESP) allows mimicking the extracellular matrix (ECM) environment of the cells and can provide fibrous scaffolds with instructive surface properties to direct cell faith into the proper lineage. Yet, these fabrication methods have some disadvantages if considered alone. This review aims at summarizing conventional and novel scaffold fabrication techniques and the biomaterials used for tissue engineering and drug-delivery applications. A new trend seems to emerge in the field of scaffold design where different scaffolds fabrication technologies and different biomaterials are combined to provide cells with mechanical, physicochemical and biological cues at the macro-, micro- and nano-scale. If merged together, these integrated technologies may lead to the generation of a new set of 3D scaffolds that satisfies all of the scaffolds' requirements for tissue-engineering applications and may contribute to their success in a long-term scenario.
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Affiliation(s)
- L Moroni
- Institute for BioMedical Technology (BMTI), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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Hadinoto K, Zhu K, Tan RBH. Drug release study of large hollow nanoparticulate aggregates carrier particles for pulmonary delivery. Int J Pharm 2007; 341:195-206. [PMID: 17467934 DOI: 10.1016/j.ijpharm.2007.03.035] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 03/10/2007] [Accepted: 03/24/2007] [Indexed: 11/26/2022]
Abstract
The aim of the present work is to examine the viability of using large hollow nanoparticulate aggregates as the therapeutic carrier particles in dry powder inhaler delivery of nanoparticulate drugs. The large hollow carrier particles are manufactured by spray drying of nanoparticulate suspensions of biocompatible acrylic polymer with loaded drugs. The size and concentration of the nanoparticles, as well as the phospholipids inclusion, have been known to influence the resulting morphology (i.e. size and degree of hollowness) of the spray-dried carrier particles. The effects of the resulting morphology of the carrier particles on the drug release rate are therefore investigated by varying the above three variables. The results of the drug release study are presented using aspirin and salbutamol sulfate as the model drugs with a varying degree of water solubility. The results indicate that the drug release rate is governed by the degree of hollowness of the carrier particles, and to a lesser extent by the nanoparticles size, as a result of the variation in the drug loading capacity of nanoparticles of different sizes.
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Affiliation(s)
- Kunn Hadinoto
- A STAR Institute of Chemical and Engineering Sciences, Singapore 627833, Singapore.
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Ito Y, Venkatesan N, Hirako N, Sugioka N, Takada K. Effect of fiber length of carbon nanotubes on the absorption of erythropoietin from rat small intestine. Int J Pharm 2007; 337:357-60. [PMID: 17270373 DOI: 10.1016/j.ijpharm.2006.12.042] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 10/25/2006] [Accepted: 12/30/2006] [Indexed: 11/21/2022]
Abstract
Erythropoietin (EPO) loaded carbon nanotubes (CNTs) with surfactant as an absorption enhancer were prepared for the oral delivery of EPO using two types of CNTs, long and short fiber length CNTs, and the effect of CNT fiber length on the absorption efficiency of EPO was studied. After Labrasol, PEG-8 caprylic/capric glycerides, as absorption enhancer was adsorbed into long fiber CNTs of which mean fiber length was 20-80 microm, as a carrier, EPO and casein as protease inhibitor and Explotab (sodium starch glycolate) as a disintegrating agent, were mixed. The resulting solid preparation was administered into the rat jejunum and serum EPO levels were measured by ELISA. The dose of EPO, CNTs, casein and Explotab were 100 IU/kg, 5mg/kg, 25mg/kg and 2.5mg/kg, respectively. Serum EPO level reached to C(max), 69.0+/-3.9 mIU/ml, at 3.5+/-0.1h and AUC was 175.7+/-13.8 mIU h/ml. These values were approximately half of that obtained with short fiber length CNTs of which C(max) was 143.1+/-15.2 mIU/ml and AUC was 256.3+/-9.7 mIU h/ml. When amphoteric surfactant, Lipomin LA, sodium beta-alkylaminopropionic acid, was used to accelerate the disaggregation of long fiber length CNTs, C(max) was 36.0+/-4.9 and AUC was 96.9+/-11.9, which showed less bioavailability (BA) of EPO. These results suggest that the short fiber length CNTs deliver more both EPO and absorption enhancer to the absorptive cells of the rat small intestine and the aggregation of CNTs is not the critical factor for the oral delivery of EPO.
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Affiliation(s)
- Yukako Ito
- Department of Pharmacokinetics, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
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24
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Preparing and evaluating delivery systems for proteins. Eur J Pharm Sci 2006; 29:174-82. [DOI: 10.1016/j.ejps.2006.05.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Accepted: 05/15/2006] [Indexed: 11/22/2022]
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Nair LS, Laurencin CT. Polymers as biomaterials for tissue engineering and controlled drug delivery. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2006; 102:47-90. [PMID: 17089786 DOI: 10.1007/b137240] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The advent of biodegradable polymers has significantly influenced the development and rapid growth of various technologies in modern medicine. Biodegradable polymers are mainly used where the transient existence of materials is required and they find applications as sutures, scaffolds for tissue regeneration, tissue adhesives, hemostats, and transient barriers for tissue adhesion, as well as drug delivery systems. Each of these applications demands materials with unique physical, chemical, biological, and biomechanical properties to provide efficient therapy. Consequently, a wide range of degradable polymers, both natural and synthetic, have been investigated for these applications. Furthermore, recent advances in molecular and cellular biology, coupled with the development of novel biotechnological drugs, necessitate the modification of existing polymers or synthesis of novel polymers for specific applications. This review highlights various biodegradable polymeric materials currently investigated for use in two key medical applications: drug delivery and tissue engineering.
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Affiliation(s)
- Lakshmi S Nair
- Department of Orthopaedic Surgery, College of Medicine, University of Virginia, Charlottesville 22903, USA
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26
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Conconi MT, Lora S, Menti AM, Carampin P, Parnigotto PP. In vitro evaluation of poly[bis(ethyl alanato)phosphazene] as a scaffold for bone tissue engineering. ACTA ACUST UNITED AC 2006; 12:811-9. [PMID: 16674294 DOI: 10.1089/ten.2006.12.811] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Polyphosphazenes with amino acid ester as side groups are biocompatible polymers that could provide valid scaffolds for cell growth. In the present study we investigate the adhesion and growth of osteoblasts obtained from rat bone marrow on matrices composed of thin fibers of poly[bis(ethyl alanato)phosphazene] (PAlaP), poly(d,l-lactic acid) (PDLLA), or PAlaP/PDLLA blend. Our data show that scaffolds of PAlaP or PAlaP/PDLLA blend enhanced the cell adhesion and growth in comparison with that observed in cultures seeded on polystyrene tissue culture plates. Although collagenase-digestible protein synthesis remained unchanged, all scaffolds induced a decrease in alkaline phosphatase activity, suggesting that osteoblasts are in the proliferation phase. Both PAlaP and PAlaP blended with PDLLA may represent a new and interesting substrate for bone tissue engineering.
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Wang LY, Gu YH, Zhou QZ, Ma GH, Wan YH, Su ZG. Preparation and characterization of uniform-sized chitosan microspheres containing insulin by membrane emulsification and a two-step solidification process. Colloids Surf B Biointerfaces 2006; 50:126-35. [PMID: 16787743 DOI: 10.1016/j.colsurfb.2006.05.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 04/06/2006] [Accepted: 05/05/2006] [Indexed: 11/22/2022]
Abstract
Chitosan microsphere has important application in controlled release of protein and peptide drug, because it shows excellent mucoadhesive and permeation enhancing effect across the biological surfaces. In the conventional preparation methods of chitosan microsphere, the W/O emulsion was usually prepared by mechanical stirring method, and then the droplets were solidified by glutaraldehyde. There existed limitation and shortage such as broad size distribution, de-activity of bio-drug and difficulty in drug release because protein and peptide drug have the same amino group as chitosan. In this study, we established a method to prepare uniform-sized microsphere, and solve above problems by combining a special membrane emulsification technique and a step-wise crosslinking method. That is, the chitosan/acetic acid aqueous solution was pressed through the uniform pores of a porous glass membrane into a paraffin/petroleum ether mixture containing PO-500 emulsifier, to form a W/O emulsion with uniform droplet size. Then, the uniform droplets were solidified by a two-step crosslinking method. At the first step, tripolyphosphate (TPP) solution was dropped gradually in the emulsion, TPP diffused into the droplet to crosslink chitosan by an ionic linkage, generating a microgel. At the second step, an adequate amount of glutaraldehyde was added. The solidification conditions of the two-step process were optimized by investigating the effects of solidification conditions on morphology of microspheres, encapsulation efficiency (EE), drug activity and release profile in vitro. The suitable preparative conditions were determined as follows: pH value of aqueous phase and TPP solution was 3.5-4.0, the molar ratio of amino group of chitosan to aldehyde group of glutaraldehyde was 1:1 and the crosslinking time of glutaraldehyde was 60 min.
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Affiliation(s)
- Lian-Yan Wang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, China
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Furtado S, Abramson D, Simhkay L, Wobbekind D, Mathiowitz E. Subcutaneous delivery of insulin loaded poly(fumaric-co-sebacic anhydride) microspheres to type 1 diabetic rats. Eur J Pharm Biopharm 2006; 63:229-36. [PMID: 16682174 DOI: 10.1016/j.ejpb.2005.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Accepted: 12/15/2005] [Indexed: 10/24/2022]
Abstract
The method of phase inversion nanoencapsulation (PIN) and microencapsulation was used to produce biodegradable poly(fumaric-co-sebacic anhydride) (p(FASA)) microspheres that contain insulin. Microspheres were characterized by SEM and a laser light scattering technique to determine particle size distribution. Insulin stability was determined by RP and SEC HPLC. Release rate studies were conducted and microspheres were administered subcutaneously (SQ) to type 1 diabetic rats to determine the bioactivity of insulin at three different dosages. Pharmacokinetic parameters for SQ experiments were measured using the trapezoidal rule by plotting average plasma insulin level (PIL) vs. time and determining peak concentration (CP), the time of peak concentration (TP), duration of PIL curve (D), and relative bioavailability (RB). When our insulin containing formulation was analyzed by HPLC, there was no evidence of high molecular weight transformation (HMWT) or deamidated products. In addition, we effectively altered the onset, peak, and duration of insulin action after SQ injection.
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Affiliation(s)
- Stacia Furtado
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
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Wang LY, Gu YH, Su ZG, Ma GH. Preparation and improvement of release behavior of chitosan microspheres containing insulin. Int J Pharm 2006; 311:187-95. [PMID: 16436319 DOI: 10.1016/j.ijpharm.2005.12.033] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 12/12/2005] [Accepted: 12/19/2005] [Indexed: 11/20/2022]
Abstract
Chitosan microsphere has potential applications in orally and other mucosally administration of protein and peptide drug, because it shows excellent mucoadhesive and permeation enhancing effect across the biological surfaces. The control of the size and size distribution of chitosan microsphere is necessary in order to improve its reproducibility, bioavailability and repeatable release behavior. Furthermore, it is a big challenge how to maintain the chemical stability of protein drug and improve its release behavior in the preparation of chitosan microspheres, because conventional crosslinking method by glutaraldehyde cannot be used in encapsulation of protein drug containing amino group. In this study, we established a method to prepare uniform-sized microsphere, and solve above problems by combining a special membrane emulsification technique and a step-wise crosslinking method. The preparative condition was optimized, and the chemical stability of protein, encapsulation efficiency, and release behavior were compared with conventional preparative method of drug-loaded chitosan microspheres. As a result, fairly uniform chitosan microspheres were obtained with a coefficient of variation (C.V.) value less than 11%, and the step-wise crosslinking method developed specially for membrane emulsification method provided the microspheres with higher encapsulation efficiency (80%), higher chemical stability of insulin (>95%), lower burst release and steady release behavior.
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Affiliation(s)
- Lian-Yan Wang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, China
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Venkatesan N, Yoshimitsu J, Ito Y, Shibata N, Takada K. Liquid filled nanoparticles as a drug delivery tool for protein therapeutics. Biomaterials 2005; 26:7154-63. [PMID: 15967493 DOI: 10.1016/j.biomaterials.2005.05.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Accepted: 05/06/2005] [Indexed: 11/24/2022]
Abstract
In the present study, an attempt was made to study the feasibility of nanoparticulate adsorbents in the presence of an absorption enhancer, as a drug delivery tool for the administration of erythropoietin (EPO) to the small intestine. Liquid filled nano- and micro-particles (LFNPS/LFMPS) were prepared using solid adsorbents such as porous silicon dioxide (Sylysia 550), carbon nanotubes (CNTs), carbon nanohorns, fullerene, charcoal and bamboo charcoal. Surfactants such as a saturated polyglycolysed C8-C18 glyceride (Gelucire 44/14), PEG-8 capryl/caprylic acid glycerides (Labrasol) and polyoxyethylene hydrogenated castor oil derivative (HCO-60) were used as an absorption enhancer at 50mg/kg along with casein/lactoferrin as enzyme inhibitors. The absorption of EPO was studied by measuring serum EPO levels by an ELISA method after small intestinal administration of EPO-LFNPS preparation to rats at the EPO dose level of 100 IU/kg. Among the adsorbents studied, CNTs showed the highest serum EPO level of 62.7 +/- 11.6 mIU/ml. In addition, with the use of casein, EPO absorption was improved, C(max) 143.1 +/- 15.2 mIU/ml. Labrasol showed the highest absorption enhancing effect after intra-jejunum administration than Gelucire 44/14 and HCO-60, 25.6 +/- 3.2 and 22.2 +/- 3.6 mIU/ml, respectively. Jejunum was found to be the best absorption site for the absorption of EPO from LFNPS. The use of CNTs as LFNPS, improved the bioavailability of EPO to 11.5% following intra-small intestinal administration.
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Affiliation(s)
- Natarajan Venkatesan
- Department of Pharmacokinetics, Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Japan.
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31
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Kapicka L, Dastych D, Richterová V, Alberti M, Kubácek P. Analysis and calculation of the 31P and 19F NMR spectra of hexafluorocyclotriphosphazene. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2005; 43:294-301. [PMID: 15674813 DOI: 10.1002/mrc.1549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The higher order high-resolution (31)P and (19)F NMR spectra of hexafluorocyclotriphosphazene (F(2)PN)(3) were measured at 183 K and interpreted using subspectral analysis and iterative fitting computation. (F(2)PN)(3) forms a rigid nine-spin system [A[X](2)](3) with D(3h) symmetry. Two complete and very similar sets of six experimental spin-spin coupling constants, (1)J(P,F), (2)J(P,P), (2)J(F,F), (3)J(P,F), (4)J(F,F)(cis) and (4)J(F,F)(trans), were determined for the first time. Theoretical DFT calculations of chemical shifts and coupling constants were performed to assess their predictive value. The PP/aug-cc-pVDZ treatment rendered the best agreement with experimental data.
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Affiliation(s)
- Libor Kapicka
- Department of Theoretical and Physical Chemistry, Faculty of Science, Masaryk University, Kotlárská 2, 61137 Brno, Czech Republic
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32
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Lin C, Gokhale R, Trivedi JS, Ranade V. Recent strategies and methods for improving insulin delivery. Drug Dev Res 2005. [DOI: 10.1002/ddr.10426] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Jorgensen L, Vermehren C, Bjerregaard S, Frokjaer S. In vitro release of insulin aspart incorporated into water-in-oil emulsions. J Drug Deliv Sci Technol 2004. [DOI: 10.1016/s1773-2247(04)50084-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Biodegradable polymers such as poly(alpha-hydroxy acids), poly(anhydrides), poly(ortho esters), poly(amino acids) and polyphosphazenes have raised considerable interest as short-term medical implants due to their transient nature. Among these, polyphosphazenes are a relatively new class of polymers, quite distinct from all the biodegradable polymers synthesized so far, due to their synthetic flexibility and versatile adaptability for applications. These are high molecular weight, essentially linear polymers with an inorganic backbone of alternating phosphorous and nitrogen atoms bearing two side groups attached to each phosphorous atom. Controlled tuning of physico-chemical properties, including biodegradability, can be achieved in this class of polymers via macromolecular substitutions. Biodegradable polyphosphazenes, due to their hydrolytic instability, nontoxic degradation products, ease of fabrication and matrix permeability, are an excellent platform for controlled drug delivery applications. This review discusses the mode of degradation and drug delivery applications of biodegradable polyphosphazenes.
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Affiliation(s)
- S Lakshmi
- Department of Chemical Engineering, Drexel University, Philadelphia, PA 19104, USA
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Eaimtrakarn S, Rama Prasad YV, Puthli SP, Yoshikawa Y, Shibata N, Takada K. Possibility of a patch system as a new oral delivery system. Int J Pharm 2003; 250:111-7. [PMID: 12480277 DOI: 10.1016/s0378-5173(02)00534-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A new oral patch system has been designed to increase the residence time of model drugs within the gastrointestinal tract. The system consisted of three layers (1) water-insoluble backing layer (2) drug-carrying adhesive layer composed of a model drug, fluorescein (FL) or fluorescein isothiocyanate-dextran (FD), and gel-forming polymer and (3) pH-sensitive enteric polymer. These three layers system was prepared as 3.0 mm diameter patches. As references, tablet containing FL or FD was prepared. In vitro dissolution studies showed that the mean dissolution time (MDT) of model drugs from patch preparation was 0.739+/-0.021 h for FL and 0.407+/-0.021 h for FD, which were longer than from tablet, 0.327+/-0.008 h for FL and 0.270+/-0.019 h for FD. The two test preparations were orally administered to beagle dogs in a crossover manner at a FL dose of 30 mg/dog and the measured plasma FL concentrations were used for pharmacokinetic analysis. With FL patch preparation, area under the plasma drug concentration vs. time curve (AUC) was 2.12+/-0.24 microgh/ml and mean residence time (MRT) was 4.60+/-0.18 h, which were greater than those of tablet, AUC was 1.52+/-0.16 microgh/ml and MRT was 3.18+/-0.09 h, respectively. Oral patch preparation also increased both AUC and MRT of FD, a model macromolecular drug, which was formulated into both patches and tablets and administered to dogs (30 mg/dog). The AUC and MRT of FD from the patch preparation were 1.11+/-0.13 microgh/ml and 5.58+/-0.55 h and from tablets were 0.53+/-0.08 microg h/ml and 4.09+/-0.29 h, respectively. These results suggest that oral patch preparation has as a potential a new oral delivery system to obtain a long residence time of drug in the gastrointestinal tract.
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Affiliation(s)
- Sudarat Eaimtrakarn
- Department of Pharmacokinetics, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
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36
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Literature alerts. J Microencapsul 2001; 18:685-92. [PMID: 11508773 DOI: 10.1080/02652040110060526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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