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Shi J, Yu L, Ding J. PEG-based thermosensitive and biodegradable hydrogels. Acta Biomater 2021; 128:42-59. [PMID: 33857694 DOI: 10.1016/j.actbio.2021.04.009] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/09/2021] [Accepted: 04/01/2021] [Indexed: 02/07/2023]
Abstract
Injectable thermosensitive hydrogels are free-flowing polymer solutions at low or room temperature, making them easy to encapsulate the therapeutic payload or cells via simply mixing. Upon injection into the body, in situ forming hydrogels triggered by body temperature can act as drug-releasing reservoirs or cell-growing scaffolds. Finally, the hydrogels are eliminated from the administration sites after they accomplish their missions as depots or scaffolds. This review outlines the recent progress of poly(ethylene glycol) (PEG)-based biodegradable thermosensitive hydrogels, especially those composed of PEG-polyester copolymers, PEG-polypeptide copolymers and poly(organophosphazene)s. The material design, performance regulation, thermogelation and degradation mechanisms, and corresponding applications in the biomedical field are summarized and discussed. A perspective on the future thermosensitive hydrogels is also highlighted. STATEMENT OF SIGNIFICANCE: Thermosensitive hydrogels undergoing reversible sol-to-gel phase transitions in response to temperature variations are a class of promising biomaterials that can serve as minimally invasive injectable systems for various biomedical applications. Hydrophilic PEG is a main component in the design and fabrication of thermoresponsive hydrogels due to its excellent biocompatibility. By incorporating hydrophobic segments, such as polyesters and polypeptides, into PEG-based systems, biodegradable and thermosensitive hydrogels with adjustable properties in vitro and in vivo have been developed and have recently become a research hotspot of biomaterials. The summary and discussion on molecular design, performance regulation, thermogelation and degradation mechanisms, and biomedical applications of PEG-based thermosensitive hydrogels may offer a demonstration of blueprint for designing new thermogelling systems and expanding their application scope.
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Patel DK, Lim KT. Biomimetic Polymer-Based Engineered Scaffolds for Improved Stem Cell Function. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2950. [PMID: 31514460 PMCID: PMC6766224 DOI: 10.3390/ma12182950] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 12/17/2022]
Abstract
Scaffolds are considered promising materials for tissue engineering applications due to their unique physiochemical properties. The high porosity and adequate mechanical properties of the scaffolds facilitate greater cell adhesion, proliferation, and differentiation. Stem cells are frequently applied in tissue engineering applications due to their excellent potential. It has been noted that cell functions are profoundly affected by the nature of the extracellular matrix (ECM). Naturally derived ECM contains the bioactive motif that also influences the immune response of the organism. The properties of polymer scaffolds mean they can resemble the native ECM and can regulate cellular responses. Various techniques such as electrospinning and 3D printing, among others, are frequently used to fabricate polymer scaffolds, and their cellular responses are different with each technique. Furthermore, enhanced cell viability, as well as the differentiation ability of stem cells on the surface of scaffolds, opens a fascinating approach to the formation of ECM-like environments for tissue engineering applications.
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Affiliation(s)
- Dinesh K Patel
- The Institute of Forest Science, Kangwon National University, Chuncheon-24341, Korea.
| | - Ki-Taek Lim
- Department of Biosystems Engineering, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon-24341, Korea.
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Vanparijs N, Nuhn L, De Geest BG. Transiently thermoresponsive polymers and their applications in biomedicine. Chem Soc Rev 2018; 46:1193-1239. [PMID: 28165097 DOI: 10.1039/c6cs00748a] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The focus of this review is on the class of transiently thermoresponsive polymers. These polymers are thermoresponsive, but gradually lose this property upon chemical transformation - often a hydrolysis reaction - in the polymer side chain or backbone. An overview of the different approaches used for the design of these polymers along with their physicochemical properties is given. Their amphiphilic properties and degradability into fully soluble compounds make this class of responsive polymers attractive for drug delivery and tissue engineering applications. Examples of these are also provided in this review.
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Affiliation(s)
- Nane Vanparijs
- Department of Pharmaceutics, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Lutz Nuhn
- Department of Pharmaceutics, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Bruno G De Geest
- Department of Pharmaceutics, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
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McKenzie M, Betts D, Suh A, Bui K, Kim LD, Cho H. Hydrogel-Based Drug Delivery Systems for Poorly Water-Soluble Drugs. Molecules 2015; 20:20397-408. [PMID: 26580588 PMCID: PMC6332288 DOI: 10.3390/molecules201119705] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/02/2015] [Accepted: 11/06/2015] [Indexed: 11/20/2022] Open
Abstract
Hydrogels are three-dimensional materials that can withstand a great amount of water incorporation while maintaining integrity. This allows hydrogels to be very unique biomedical materials, especially for drug delivery. Much effort has been made to incorporate hydrophilic molecules in hydrogels in the field of drug delivery, while loading of hydrophobic drugs has not been vastly studied. However, in recent years, research has also been conducted on incorporating hydrophobic molecules within hydrogel matrices for achieving a steady release of drugs to treat various ailments. Here, we summarize the types of hydrogels used as drug delivery vehicles, various methods to incorporate hydrophobic molecules in hydrogel matrices, and the potential therapeutic applications of hydrogels in cancer.
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Affiliation(s)
- Matthew McKenzie
- Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO 63110, USA.
| | - David Betts
- Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO 63110, USA.
| | - Amy Suh
- Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO 63110, USA.
| | - Kathryn Bui
- Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO 63110, USA.
| | - London Doyoung Kim
- Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO 63110, USA.
| | - Hyunah Cho
- Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, 4588 Parkview Place, St. Louis, MO 63110, USA.
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Preparation of injectable and thermoresponsive hydrogel based on penta-block copolymer with improved sol stability and mechanical properties. POLYMER 2013. [DOI: 10.1016/j.polymer.2013.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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King A, Presnall D, Steely LB, Allcock HR, Wynne KJ. Semicrystalline polyphosphazenes: A comparative study of topology, morphology, and contact angles for three fluorous and one aryl polyphosphazene. POLYMER 2013. [DOI: 10.1016/j.polymer.2012.12.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Zhai Y, Deng L, Xing J, Liu Y, Zhang Q, Dong A. A New Injectable Thermogelling Material: Methoxy Poly(ethylene glycol)–Poly(sebacic acid-D,L-lactic acid)–Methoxy Poly(ethylene glycol) Triblock Co-polymer. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 20:923-34. [DOI: 10.1163/156856209x444349] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Yinglei Zhai
- a School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Liandong Deng
- b School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Jinfeng Xing
- c School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Yu Liu
- d School of Pharmaceutical Sciences, Peking University, Beijing, P. R. China
| | - Qiang Zhang
- e School of Pharmaceutical Sciences, Peking University, Beijing, P. R. China
| | - Anjie Dong
- f School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China
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Affiliation(s)
- Tina Vermonden
- Department of Pharmaceutics, Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
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Poly-dioxybiphenyl phosphazene random copolymers with pendant 3-hydroxy-propyl groups and polycaprolactone branches. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.03.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lee K, Silva EA, Mooney DJ. Growth factor delivery-based tissue engineering: general approaches and a review of recent developments. J R Soc Interface 2011; 8:153-70. [PMID: 20719768 PMCID: PMC3033020 DOI: 10.1098/rsif.2010.0223] [Citation(s) in RCA: 908] [Impact Index Per Article: 69.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 07/29/2010] [Indexed: 12/23/2022] Open
Abstract
The identification and production of recombinant morphogens and growth factors that play key roles in tissue regeneration have generated much enthusiasm and numerous clinical trials, but the results of many of these trials have been largely disappointing. Interestingly, the trials that have shown benefit all contain a common denominator, the presence of a material carrier, suggesting strongly that spatio-temporal control over the location and bioactivity of factors after introduction into the body is crucial to achieve tangible therapeutic effect. Sophisticated materials systems that regulate the biological presentation of growth factors represent an attractive new generation of therapeutic agents for the treatment of a wide variety of diseases. This review provides an overview of growth factor delivery in tissue engineering. Certain fundamental issues and design strategies relevant to the material carriers that are being actively pursued to address specific technical objectives are discussed. Recent progress highlights the importance of materials science and engineering in growth factor delivery approaches to regenerative medicine.
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Affiliation(s)
- Kangwon Lee
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
| | - Eduardo A. Silva
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
| | - David J. Mooney
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
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Abstract
Current strategies of regenerative medicine are focused on the restoration of pathologically altered tissue architectures by transplantation of cells in combination with supportive scaffolds and biomolecules. In recent years, considerable interest has been given to biologically active scaffolds which are based on similar analogs of the extracellular matrix that have induced synthesis of tissues and organs. To restore function or regenerate tissue, a scaffold is necessary that will act as a temporary matrix for cell proliferation and extracellular matrix deposition, with subsequent ingrowth until the tissues are totally restored or regenerated. Scaffolds have been used for tissue engineering such as bone, cartilage, ligament, skin, vascular tissues, neural tissues, and skeletal muscle and as vehicle for the controlled delivery of drugs, proteins, and DNA. Various technologies come together to construct porous scaffolds to regenerate the tissues/organs and also for controlled and targeted release of bioactive agents in tissue engineering applications. In this paper, an overview of the different types of scaffolds with their material properties is discussed. The fabrication technologies for tissue engineering scaffolds, including the basic and conventional techniques to the more recent ones, are tabulated.
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Jadhav VB, Toti US, Cui JX, Jun YJ, Sohn YS. Amphiphilic Cyclotriphosphazenes Grafted with Branched Oligopeptides. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.12.3735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kretlow JD, Young S, Klouda L, Wong M, Mikos AG. Injectable biomaterials for regenerating complex craniofacial tissues. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2009; 21:3368-93. [PMID: 19750143 PMCID: PMC2742469 DOI: 10.1002/adma.200802009] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Engineering complex tissues requires a precisely formulated combination of cells, spatiotemporally released bioactive factors, and a specialized scaffold support system. Injectable materials, particularly those delivered in aqueous solution, are considered ideal delivery vehicles for cells and bioactive factors and can also be delivered through minimally invasive methods and fill complex 3D shapes. In this review, we examine injectable materials that form scaffolds or networks capable of both replacing tissue function early after delivery and supporting tissue regeneration over a time period of weeks to months. The use of these materials for tissue engineering within the craniofacial complex is challenging but ideal as many highly specialized and functional tissues reside within a small volume in the craniofacial structures and the need for minimally invasive interventions is desirable due to aesthetic considerations. Current biomaterials and strategies used to treat craniofacial defects are examined, followed by a review of craniofacial tissue engineering, and finally an examination of current technologies used for injectable scaffold development and drug and cell delivery using these materials.
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Affiliation(s)
- James D. Kretlow
- Department of Bioengineering, Rice University, P.O. Box 1892, MS 142, Houston, TX 77251-1892 (U.S.A.)
| | - Simon Young
- Department of Bioengineering, Rice University, P.O. Box 1892, MS 142, Houston, TX 77251-1892 (U.S.A.)
| | - Leda Klouda
- Department of Bioengineering, Rice University, P.O. Box 1892, MS 142, Houston, TX 77251-1892 (U.S.A.)
| | - Mark Wong
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at Houston, 6515 M.D. Anderson Blvd., Suite DBB 2.059, Houston, TX 770030 (U.S.A.)
| | - Antonios G. Mikos
- Department of Bioengineering, Rice University, P.O. Box 1892, MS 142, Houston, TX 77251-1892 (U.S.A.)
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Joo MK, Park MH, Choi BG, Jeong B. Reverse thermogelling biodegradable polymer aqueous solutions. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b902208b] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hacker MC, Klouda L, Ma BB, Kretlow JD, Mikos AG. Synthesis and characterization of injectable, thermally and chemically gelable, amphiphilic poly(N-isopropylacrylamide)-based macromers. Biomacromolecules 2008; 9:1558-70. [PMID: 18481893 DOI: 10.1021/bm8000414] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, we synthesized and characterized a series of macromers based on poly( N-isopropylacrylamide) that undergo thermally induced physical gelation and, following chemical modification, can be chemically cross-linked. Macromers with number average molecular weights typically ranging from 2000-3500 Da were synthesized via free radical polymerization from, in addition to N-isopropylacrylamide, pentaerythritol diacrylate monostearate, a bifunctional monomer containing a long hydrophobic chain, acrylamide, a hydrophilic monomer, and hydroxyethyl acrylate, a hydrophilic monomer used to provide hydroxyl groups for further chemical modification. Results indicated that the hydrophobic-hydrophilic balance achieved by varying the relative concentrations of comonomers used during synthesis was an important parameter in controlling the transition temperature of the macromers in solution and stability of the resultant gels. Storage moduli of the macromers increased over 4 orders of magnitude once gelation occurred above the transition temperature. Furthermore, chemical cross-linking of these macromers resulted in gels with increased stability compared to uncross-linked controls. These results demonstrate the feasibility of synthesizing poly( N-isopropylacrylamide)-based macromers that undergo tandem gelation and establish key criteria relating to the transition temperature and stability of these materials. The data suggest that these materials may be attractive substrates for tissue engineering and cellular delivery applications as the combination of mechanistically independent gelation techniques used in tandem may offer superior materials with regard to gelation kinetics and stability.
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Affiliation(s)
- Michael C Hacker
- Department of Bioengineering, Rice University, MS-142, Post Office Box 1892, Houston, Texas 77251-1892, USA
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Hiemstra C, Zhou W, Zhong Z, Wouters M, Feijen J. Rapidly in situ forming biodegradable robust hydrogels by combining stereocomplexation and photopolymerization. J Am Chem Soc 2007; 129:9918-26. [PMID: 17645336 DOI: 10.1021/ja072113p] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Our previous studies have shown that stereocomplexed hydrogels can be rapidly formed in vitro as well as in vivo upon mixing aqueous solutions of eight-arm poly(ethylene glycol)-poly(l-lactide) (PEG-PLLA) and poly(ethylene glycol)-poly(d-lactide) (PEG-PDLA) star block copolymers. In this study, stereocomplexation and photopolymerization are combined to yield rapidly in situ forming robust hydrogels. Two types of methacrylate-functionalized PEG-PLLA and PEG-PDLA star block copolymers, PEG-PLLA-MA and PEG-PDLA-MA, which have methacrylate groups at the PLA chain ends and PEG-MA/PLLA and PEG-MA/PDLA, which have methacrylate groups at the PEG chain ends, were designed and prepared. Results showed that stereocomplexed hydrogels could be rapidly formed (within 1-2 min) in a polymer concentration range of 12.5-17.5% (w/v), in which the methacrylate group hardly interfered with the stereocomplexation. When subsequently photopolymerized, these hydrogels showed largely increased storage moduli as compared to the corresponding hydrogels that were cross-linked by stereocomplexation or photopolymerization only. Interestingly, the storage modulus of stereocomplexed-photopolymerized PEG-PLA-MA hydrogels increased linearly with increasing stereocomplexation equilibration time prior to photopolymerization (from ca. 6 to 32 kPa), indicating that stereocomplexation aids in photopolymerization. Importantly, photopolymerization of stereocomplexed hydrogels could take place at very low initiator concentrations (0.003 wt %). Swelling/degradation studies showed that combining stereocomplexation and photopolymerization yielded hydrogels with prolonged degradation times as compared to corresponding hydrogels cross-linked by photopolymerization only (3 vs 1.5 weeks). Stereocomplexed-photopolymerized PEG-MA/PLA hydrogels degraded much slower than corresponding PEG-PLA-MA hydrogels, with degradation times ranging from 7 to more than 16 weeks. Therefore, combining stereocomplexation and photopolymerization is a novel approach to obtain rapidly in situ forming robust hydrogels.
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Affiliation(s)
- Christine Hiemstra
- Department of Polymer Chemistry and Biomaterials, Faculty of Science and Technology, Institute for Biomedical Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Kretlow JD, Klouda L, Mikos AG. Injectable matrices and scaffolds for drug delivery in tissue engineering. Adv Drug Deliv Rev 2007; 59:263-73. [PMID: 17507111 DOI: 10.1016/j.addr.2007.03.013] [Citation(s) in RCA: 429] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Accepted: 03/28/2007] [Indexed: 11/22/2022]
Abstract
Injectable matrices and depots have been the subject of much research in the field of drug delivery. The classical tissue engineering paradigm includes a matrix or scaffold to facilitate tissue growth and provide structural support, cells, and the delivery of bioactive molecules. As both tissue engineering and drug delivery techniques benefit from the use of injectable materials due to the minimal invasiveness of an injection, significant crossover should be observed between injectable materials in both fields. This review aims to outline injectable materials and processing techniques used in both tissue engineering and drug delivery and to describe methods by which current injectable materials in the field of drug delivery can be adapted for use as injectable scaffolds for tissue engineering.
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Affiliation(s)
- James D Kretlow
- Department of Bioengineering, Rice University, Houston, TX 77251-1892, USA
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Chitkara D, Shikanov A, Kumar N, Domb AJ. Biodegradable Injectable In Situ Depot-Forming Drug Delivery Systems. Macromol Biosci 2006; 6:977-90. [PMID: 17128422 DOI: 10.1002/mabi.200600129] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The scope of drug-delivery systems has expanded significantly in recent years providing new ways to deliver life saving therapeutics to patients. The development of new injectable drug-delivery systems has provided new vistas and opened up unexplored horizons in the field of science, particularly in controlled drug delivery since these systems possess unique advantages over traditional ones, which include ease of application, and localized and prolonged drug delivery. In the past few years, an increasing number of such systems has been reported in the literature for various biomedical applications, including drug delivery, cell encapsulation, and tissue repair. These are injectable fluids that can be introduced into the body in a minimally invasive manner prior to solidifying or gelling within the desired site. For this purpose both natural (chitosan, alginates) as well as synthetic polymers (PEGylated polyesters, ricinoleic acid-based polymers) have been utilized. These systems have been explored widely for the delivery of various therapeutic agents ranging for anti-neoplastic agents like paclitaxel to proteins and peptides such as insulin, almost covering every segment of the pharmaceutical field. This manuscript focuses on the recent advancements in the area of in situ forming biodegradable polymeric drug-delivery systems.
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Affiliation(s)
- Deepak Chitkara
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Sec. 67, SAS Nagar, Mohali 160062, India
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