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Ng F, Nicoulin V, Peloso C, Curia S, Richard J, Lopez-Noriega A. In Vitro and In Vivo Hydrolytic Degradation Behaviors of a Drug-Delivery System Based on the Blend of PEG and PLA Copolymers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:55495-55509. [PMID: 38011651 DOI: 10.1021/acsami.2c13141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
This paper presents the in vitro and in vivo degradation of BEPO, a marketed in situ forming depot technology used for the formulation of long-acting injectables. BEPO is composed of a solution of a blend of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) triblock and diblock in an organic solvent, where a therapeutic agent may be dissolved or suspended. Upon contact with an aqueous environment, the solvent diffuses and the polymers precipitate, entrapping the drug and forming a reservoir. Two representative BEPO compositions were subjected to a 3-month degradation study in vitro by immersion in phosphate-buffered saline at 37 °C and in vivo after subcutaneous injection in minipig. The material erosion rate, as a surrogate of the bioresorption, determined via the depot weight loss, changed substantially, depending on the composition and content of polymers within the test item. The swelling properties and internal morphology of depots were shown to be highly dependent on the solvent exchange rate during the precipitation step. Thermal analyses displayed an increase of the depot glass transition temperature over the degradation process, with no crystallinity observed at any stage. The chemical composition of degraded depots was determined by 1H NMR and gel permeation chromatography and demonstrated an enrichment in homopolymers, i.e., free PLA and (m)PEG, to the detriment of (m)PEG-PLA copolymers in both formulations. It was observed that the relative ratio of the degradants within the depot is driven by the initial polymer composition. Interestingly, in vitro and in vivo results showed very good qualitative consistency. Taken together, the outcomes from this study demonstrate that the different hydrolytic degradation behaviors of the BEPO compositions can be tuned by adjusting the polymer composition of the formulation.
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Affiliation(s)
- Feifei Ng
- MedinCell S.A., 3 Rue des Frères Lumière, 34830 Jacou, France
| | - Victor Nicoulin
- MedinCell S.A., 3 Rue des Frères Lumière, 34830 Jacou, France
| | | | - Silvio Curia
- MedinCell S.A., 3 Rue des Frères Lumière, 34830 Jacou, France
| | - Joël Richard
- MedinCell S.A., 3 Rue des Frères Lumière, 34830 Jacou, France
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Park J, Park E, Choi SQ, Wu J, Park J, Lee H, Kim H, Lee H, Seo M. Biodegradable Block Copolymer-Tannic Acid Glue. JACS AU 2022; 2:1978-1988. [PMID: 36186559 PMCID: PMC9516699 DOI: 10.1021/jacsau.2c00241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 06/16/2023]
Abstract
Bioadhesives are becoming an essential and important ingredient in medical science. Despite numerous reports, developing adhesive materials that combine strong adhesion, biocompatibility, and biodegradation remains a challenging task. Here, we present a biocompatible yet biodegradable block copolymer-based waterborne superglue that leads to an application of follicle-free hair transplantation. Our design strategy bridges self-assembled, temperature-sensitive block copolymer nanostructures with tannic acid as a sticky and biodegradable polyphenolic compound. The formulation further uniquely offers step-by-step increases in adhesion strength via heating-cooling cycles. Combining the modular design with the thermal treating process enhances the mechanical properties up to 5 orders of magnitude compared to the homopolymer formulation. This study opens a new direction in bioadhesive formulation strategies utilizing block copolymer nanotechnology for systematic and synergistic control of the material's properties.
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Affiliation(s)
- Jongmin Park
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Eunsook Park
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Siyoung Q. Choi
- Department
of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Korea
| | - Jingxian Wu
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Jihye Park
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Hyeonju Lee
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Hyungjun Kim
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Haeshin Lee
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
| | - Myungeun Seo
- Department
of Chemistry, Korea Advanced Institute of
Science and Technology (KAIST), Daejeon 34141, Korea
- KAIST
Institute for Nanocentury, KAIST, Daejeon 34141, Korea
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Physico-Chemical Characteristics and Posterolateral Fusion Performance of Biphasic Calcium Phosphate with Submicron Needle-Shaped Surface Topography Combined with a Novel Polymer Binder. MATERIALS 2022; 15:ma15041346. [PMID: 35207887 PMCID: PMC8880136 DOI: 10.3390/ma15041346] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 12/04/2022]
Abstract
A biphasic calcium phosphate with submicron needle-shaped surface topography combined with a novel polyethylene glycol/polylactic acid triblock copolymer binder (BCP-EP) was investigated in this study. This study aims to evaluate the composition, degradation mechanism and bioactivity of BCP-EP in vitro, and its in vivo performance as an autograft bone graft (ABG) extender in a rabbit Posterolateral Fusion (PLF) model. The characterization of BCP-EP and its in vitro degradation products showed that the binder hydrolyses rapidly into lactic acid, lactide oligomers and unaltered PEG (polyethylene glycol) without altering the BCP granules and their characteristic submicron needle-shaped surface topography. The bioactivity of BCP-EP after immersion in SBF revealed a progressive surface mineralization. In vivo, BCP-EP was assessed in a rabbit PLF model by radiography, manual palpation, histology and histomorphometry up to 12 weeks post-implantation. Twenty skeletally mature New Zealand (NZ) White Rabbits underwent single-level intertransverse process PLF surgery at L4/5 using (1) autologous bone graft (ABG) alone or (2) by mixing in a 1:1 ratio with BCP-EP (BCP-EP/ABG). After 3 days of implantation, histology showed the BCP granules were in direct contact with tissues and cells. After 12 weeks, material resorption and mature bone formation were observed, which resulted in solid fusion between the two transverse processes, following all assessment methods. BCP-EP/ABG showed comparable fusion rates with ABG at 12 weeks, and no graft migration or adverse reaction were noted at the implantation site nor in distant organs.
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Malhotra M, Surnar B, Jayakannan M. Polymer Topology Driven Enzymatic Biodegradation in Polycaprolactone Block and Random Copolymer Architectures for Drug Delivery to Cancer Cells. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01793] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Mehak Malhotra
- Department of Chemistry, Indian Institute of Science Education and Research-Pune, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| | - Bapurao Surnar
- Department of Chemistry, Indian Institute of Science Education and Research-Pune, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
| | - Manickam Jayakannan
- Department of Chemistry, Indian Institute of Science Education and Research-Pune, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India
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Lins LC, Wianny F, Livi S, Hidalgo IA, Dehay C, Duchet-Rumeau J, Gérard JF. Development of Bioresorbable Hydrophilic–Hydrophobic Electrospun Scaffolds for Neural Tissue Engineering. Biomacromolecules 2016; 17:3172-3187. [DOI: 10.1021/acs.biomac.6b00820] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Luanda Chaves Lins
- Ingénierie
des Matériaux Polymères CNRS, UMR 5223; INSA Lyon, Université de Lyon, F-69621 Villeurbanne, France
| | - Florence Wianny
- Inserm,
Stem Cell and Brain Research Institute U1208, Univ Lyon, Université Claude Bernard Lyon 1, 69500 Bron, France
| | - Sébastien Livi
- Ingénierie
des Matériaux Polymères CNRS, UMR 5223; INSA Lyon, Université de Lyon, F-69621 Villeurbanne, France
| | - Idalba Andreina Hidalgo
- Ingénierie
des Matériaux Polymères CNRS, UMR 5223; INSA Lyon, Université de Lyon, F-69621 Villeurbanne, France
| | - Colette Dehay
- Inserm,
Stem Cell and Brain Research Institute U1208, Univ Lyon, Université Claude Bernard Lyon 1, 69500 Bron, France
| | - Jannick Duchet-Rumeau
- Ingénierie
des Matériaux Polymères CNRS, UMR 5223; INSA Lyon, Université de Lyon, F-69621 Villeurbanne, France
| | - Jean-François Gérard
- Ingénierie
des Matériaux Polymères CNRS, UMR 5223; INSA Lyon, Université de Lyon, F-69621 Villeurbanne, France
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Phase Separation and Elastic Properties of Poly(Trimethylene Terephthalate)-block-poly(Ethylene Oxide) Copolymers. Polymers (Basel) 2016; 8:polym8070237. [PMID: 30974518 PMCID: PMC6432139 DOI: 10.3390/polym8070237] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/09/2016] [Accepted: 06/14/2016] [Indexed: 11/17/2022] Open
Abstract
A series of poly(trimethylene terephthalate)-block-poly(ethylene oxide) (PTT-b-PEOT) copolymers with different compositions of rigid PTT and flexible PEOT segments were synthesized via condensation in the melt. The influence of the block length and the block ratio on the micro-separated phase structure and elastic properties of the synthesized multiblock copolymers was studied. The PEOT segments in these copolymers were kept constant at 1130, 2130 or 3130 g/mol, whereas the PTT content varied from 30 up to 50 wt %. The phase separation was assessed using differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The crystal structure of the synthesised block copolymers and their microstructure on the manometer scale was evaluated by using WAXS and SAXS analysis. Depending on the PTT/PEOT ratio, but also on the rigid and flexible segment length in PTT-b-PEO copolymers, four different domains were observed i.e.,: a crystalline PTT phase, a crystalline PEO phase (which exists for the whole series based on three types of PEOT segments), an amorphous PTT phase (only at 50 wt % content of PTT rigid segments) and an amorphous PEO phase. Moreover, the elastic deformability and reversibility of PTT-b-PEOT block copolymers were studied during a cyclic tensile test. Determined values of permanent set resultant from maximum attained stain (100% and 200%) for copolymers were used to evaluate their elastic properties.
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Kutikov AB, Song J. Biodegradable PEG-Based Amphiphilic Block Copolymers for Tissue Engineering Applications. ACS Biomater Sci Eng 2015; 1:463-480. [PMID: 27175443 PMCID: PMC4860614 DOI: 10.1021/acsbiomaterials.5b00122] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Biodegradable tissue engineering scaffolds have great potential for delivering cells/therapeutics and supporting tissue formation. Polyesters, the most extensively investigated biodegradable synthetic polymers, are not ideally suited for diverse tissue engineering applications due to limitations associated with their hydrophobicity. This review discusses the design and applications of amphiphilic block copolymer scaffolds integrating hydrophilic poly(ethylene glycol) (PEG) blocks with hydrophobic polyesters. Specifically, we highlight how the addition of PEG results in striking changes to the physical properties (swelling, degradation, mechanical, handling) and biological performance (protein & cell adhesion) of the degradable synthetic scaffolds in vitro. We then perform a critical review of how these in vitro characteristics translate to the performance of biodegradable amphiphilic block copolymer-based scaffolds in the repair of a variety of tissues in vivo including bone, cartilage, skin, and spinal cord/nerve. We conclude the review with recommendations for future optimizations in amphiphilic block copolymer design and the need for better-controlled in vivo studies to reveal the true benefits of the amphiphilic synthetic tissue scaffolds.
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Affiliation(s)
- Artem B. Kutikov
- Department of Orthopedics and Physical Rehabilitation. University of Massachusetts Medical School. 55 Lake Ave North, Worcester, MA 01655, USA
| | - Jie Song
- Department of Orthopedics and Physical Rehabilitation. University of Massachusetts Medical School. 55 Lake Ave North, Worcester, MA 01655, USA
- Department of Cell and Developmental Biology. University of Massachusetts Medical School. 55 Lake Ave North, Worcester, MA 01655, USA
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Kutikov AB, Song J. An amphiphilic degradable polymer/hydroxyapatite composite with enhanced handling characteristics promotes osteogenic gene expression in bone marrow stromal cells. Acta Biomater 2013; 9:8354-64. [PMID: 23791675 PMCID: PMC3745304 DOI: 10.1016/j.actbio.2013.06.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 05/31/2013] [Accepted: 06/10/2013] [Indexed: 01/13/2023]
Abstract
Electrospun polymer/hydroxyapatite (HA) composites combining biodegradability with osteoconductivity are attractive for skeletal tissue engineering applications. However, most biodegradable polymers such as poly(lactic acid) (PLA) are hydrophobic and do not blend with adequate interfacial adhesion with HA, compromising the structural homogeneity, mechanical integrity and biological performance of the composite. To overcome this challenge, we combined a hydrophilic polyethylene glycol (PEG) block with poly(d,l-lactic acid) to improve the adhesion of the degradable polymer with HA. The amphiphilic triblock copolymer PLA-PEG-PLA (PELA) improved the stability of HA-PELA suspension at 25wt.% HA content, which was readily electrospun into HA-PELA composite scaffolds with uniform fiber dimensions. HA-PELA was highly extensible (failure strain>200% vs. <40% for HA-PLA), superhydrophilic (∼0° water contact angle vs. >100° for HA-PLA), and exhibited an 8-fold storage modulus increase (unlike deterioration for HA-PLA) upon hydration, owing to the favorable interaction between HA and PEG. HA-PELA also better promoted osteochondral lineage commitment of bone marrow stromal cells in unstimulated culture and supported far more potent osteogenic gene expression upon induction than HA-PLA. We demonstrate that the chemical incorporation of PEG is an effective strategy to improve the performance of degradable polymer/HA composites for bone tissue engineering applications.
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Affiliation(s)
- Artem B. Kutikov
- Department of Orthopedics & Physical Rehabilitation, Department of Cell and Developmental Biology. University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
| | - Jie Song
- Department of Orthopedics & Physical Rehabilitation, Department of Cell and Developmental Biology. University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
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9
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Chen B, Han B, Song L, Xu D, Pei J. A Novel Preparation Method for Octreotide Acetate-Loaded PLGA Microspheres with a High Drug-Loading Capacity and a Low Initial Burst Release, and Its Studies on Relations between In Vitro and In Vivo Release. ADVANCES IN POLYMER TECHNOLOGY 2013. [DOI: 10.1002/adv.21354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Bin Chen
- Department of Biopharmacy, School of Pharmaceutical Sciences; Jilin University; Changchun; 130021; People's Republic of China
| | - Bing Han
- Department of Biopharmacy, School of Pharmaceutical Sciences; Jilin University; Changchun; 130021; People's Republic of China
| | - Liping Song
- Department of Biopharmacy, School of Pharmaceutical Sciences; Jilin University; Changchun; 130021; People's Republic of China
| | - Dan Xu
- Department of Biopharmacy, School of Pharmaceutical Sciences; Jilin University; Changchun; 130021; People's Republic of China
| | - Jin Pei
- Department of Biopharmacy, School of Pharmaceutical Sciences; Jilin University; Changchun; 130021; People's Republic of China
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11
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Zhong Q, Ren J, Wang Q. Preparation and characterization of polylactide-block
-poly(butylene adipate) polyurethane thermoplastic elastomer. POLYM ENG SCI 2011. [DOI: 10.1002/pen.21911] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Thieme M, Agarwal S, Wendorff JH, Greiner A. Electrospinning and cutting of ultrafine bioerodible poly(lactide-co-ethylene oxide) tri- and multiblock copolymer fibers for inhalation applications. POLYM ADVAN TECHNOL 2009. [DOI: 10.1002/pat.1617] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Li J, Jiang G, Ding F. The effect of pH on the polymer degradation and drug release from PLGA-mPEG microparticles. J Appl Polym Sci 2008. [DOI: 10.1002/app.28122] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Spinu M, Jackson C, Keating MY, Gardner KH. Material Design in Poly(Lactic Acid) Systems: Block Copolymers, Star Homo- and Copolymers, and Stereocomplexes. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2006. [DOI: 10.1080/10601329608014922] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Tew GN, Sanabria-DeLong N, Agrawal SK, Bhatia SR. New properties from PLA-PEO-PLA hydrogels. SOFT MATTER 2005; 1:253-258. [PMID: 32646115 DOI: 10.1039/b509800a] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Polymeric materials are important in many medical applications. Regenerative medicine offers the potential to repair or replace damaged tissue and polymers are an essential component of many tissue engineering approaches. Hydrogels have many advantageous properties but, generally, lack robust mechanical properties. At the same time, mounting evidence points to the importance of the matrix modulus when constructing devices. In this context, triblock copolymers made from poly(-lactide)-poly(ethylene glycol)-poly(-lactide) have been prepared and formulated into hydrogels. Investigations into their mechanical properties found the elastic modulus to be greater than 10 kPa which is at least one order of magnitude stiffer than previously reported from macromolecules composed of similar monomers. Part of the reason is the presence of crystalline lactide domains. Creating hydrogels with tailored modulus across the kPa range will likely have important ramifications in regenerative medicine.
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Affiliation(s)
- Gregory N Tew
- Department of Polymer Science Engineering, University of Massachusetts, Amherst, 120 Governors Drive, Amherst, MA 01003, USA.
| | - Naomi Sanabria-DeLong
- Department of Polymer Science Engineering, University of Massachusetts, Amherst, 120 Governors Drive, Amherst, MA 01003, USA.
| | - Sarvesh K Agrawal
- Department of Chemical Engineering, University of Massachusetts, Amherst, 686 North Pleasant Street, Amherst, MA 01003, USA.
| | - Surita R Bhatia
- Department of Chemical Engineering, University of Massachusetts, Amherst, 686 North Pleasant Street, Amherst, MA 01003, USA.
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Cohn D, Salomon AH. Designing biodegradable multiblock PCL/PLA thermoplastic elastomers. Biomaterials 2005; 26:2297-305. [PMID: 15585232 DOI: 10.1016/j.biomaterials.2004.07.052] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2004] [Accepted: 07/23/2004] [Indexed: 11/27/2022]
Abstract
A series of poly(epsilon-caprolactone)/poly(L-lactic acid) (PCL/PLA) biodegradable poly(ester-urethane)s, was synthesized and characterized. The first step of the synthesis consisted of the ring opening polymerization of L-lactide, initiated by the hydroxyl terminal groups of the PCL chain, followed by the chain extension of these PLA-PCL-PLA triblocks, using hexamethylene diisocyanate (HDI). The trimers comprised PCL2000 flexible segments, while the length of each PLA block covered the 550-6000 molecular weight range. The morphology of the copolymers gradually changed, as the length of the PLA blocks increased. The multiblock copolymers produced displayed enhanced mechanical properties, with ultimate tensile strength values around 32 MPa, Young's modulus as low as 30 MPa and elongation at break values well above 600%. The longer the PLA block, the slower the in vitro degradation of the material, with all copolymers degrading faster than the respective homopolymers.
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Affiliation(s)
- D Cohn
- Casali Institute of Applied Chemistry, Hebrew University of Jerusalem, Gival Ram Campus, Jerusalem 91904, Israel
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Cohn D, Hotovely-Salomon A. Biodegradable multiblock PEO/PLA thermoplastic elastomers: molecular design and properties. POLYMER 2005. [DOI: 10.1016/j.polymer.2005.01.012] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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18
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Tjong SC, Bei JZ. Degradation behavior of poly (caprolactone)-poly(ethylene glycol) block copolymer/low-density polyethylene blends. POLYM ENG SCI 2004. [DOI: 10.1002/pen.10200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Friess W, Schlapp M. Modifying the release of gentamicin from microparticles using a PLGA blend. Pharm Dev Technol 2002; 7:235-48. [PMID: 12066578 DOI: 10.1081/pdt-120003491] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Carrier systems for local gentamicin (GS) treatment based on collagen sponges and polymethylmethacrylate beads show pharmacokinetic disadvantages in their GS-release profiles. Therefore, poly(lactic-co-glycolic acid) (PLGA) microparticles were devised. None of the five poly(alpha-hydroxy acid)s tested resulted in the desired antibiotic release over approximately one week. However, preparing microparticles from a 50/50 blend of Resomer RG 502H, an uncapped variety, and Resomer RG 503, an endcapped polymer, yielded the targeted liberation profile. The mechanism of GS release was investigated by analyzing water uptake and polymer molecular weight. Release of GS from RG 502H particles occurred instantaneously and coincided with substantial water penetration. Particles prepared from RG 503 started out at a higher molecular weight and since the endcapped polymer takes up less water, the decrease in molecular weight was delayed. The threshold of collapse was reached after two weeks, which coincided with water penetration and GS release. For the 50/50 RG 502H/RG 503 blend, this process was delayed for two to three days. Hydrolysis occurred at the same rate as for RG 502H due to the high water content as a consequence of the uncapped polymer fraction and renders GS release over one week with release limited to 30% in the first two days due to the endcapped polymer fraction of higher molecular weight. Thus, the mixture of endcapped and uncapped Resome exhibits a new quality for adjusting drug release from poly(alpha-hydroxy acid)s.
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Affiliation(s)
- Wolfgang Friess
- Department of Pharmaceutical Technology, University of Erlangen, Cauerstr. 4, 91058 Erlangen, Germany.
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Cohn D, Stern T, González MF, Epstein J. Biodegradable poly(ethylene oxide)/poly(epsilon-caprolactone) multiblock copolymers. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2002; 59:273-81. [PMID: 11745563 DOI: 10.1002/jbm.1242] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A series of poly(ethylene oxide) (PEO)/poly(epsilon-caprolactone) (PCL) containing biodegradable poly(ether ester urethane)s, covering a wide range of compositions, were synthesized and characterized. The synthesis consisted of a two-step process. During the first step, the ring-opening reaction of epsilon-caprolactone was carried out, initiated by the hydroxyl terminal groups of the PEO chain. The second step involved the chain extension of these PCL-PEO-PCL trimers with hexamethylene diisocyanate. By varying either the ethylene oxide/epsilon-caprolactone ratio or the length of both segments, we obtained a series of polymers having different morphologies and displaying a broad range of properties.
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Affiliation(s)
- Daniel Cohn
- Casali Institute of Applied Chemistry, Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
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Kissel T, Li Y, Unger F. ABA-triblock copolymers from biodegradable polyester A-blocks and hydrophilic poly(ethylene oxide) B-blocks as a candidate for in situ forming hydrogel delivery systems for proteins. Adv Drug Deliv Rev 2002; 54:99-134. [PMID: 11755708 DOI: 10.1016/s0169-409x(01)00244-7] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Hydrogels are very attractive delivery systems for hydrophilic macromolecules such as proteins and DNA because they provide a protective environment and allow control of diffusion by adjusting cross-link densities. Physically cross-linked hydrogels generated by rapid swelling upon exposure to an aqueous environment can be obtained from ABA triblock copolymers containing hydrophobic polyester A-blocks and hydrophilic polyether B-blocks. They provide an attractive alternative to chemically cross-linked systems since they allow incorporation of macromolecular drug substances under mild process conditions. Moreover, they show controlled degradation behavior and excellent biocompatibility. In this review the synthesis and characterization of ABA triblock copolymers from polyester hard segments and poly(ethylene oxide) [PEO] soft segments as well as their biological and degradation properties will be discussed. Their use as biodegradable drug delivery devices in the form of implants, micro- and nanospheres has attracted considerable interest especially for proteins and may provide an alternative to poly(lactide-co-glycolide).
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Affiliation(s)
- Thomas Kissel
- Department of Pharmaceutics and Biopharmacy, Philipps-University Marburg, Ketzerbach 63, D-35032 Marburg, Germany.
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Watanabe J, Ooya T, Yui N. Effect of acetylation of biodegradable polyrotaxanes on its supramolecular dissociation via terminal ester hydrolysis. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2000; 10:1275-88. [PMID: 10673022 DOI: 10.1163/156856299x00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Acetylation of biodegradable polyrotaxanes was examined to estimate the effect on its supramolecular dissociation via terminal ester hydrolysis. The biodegradable polyrotaxanes, in which many alpha-cyclodextrins (alpha-CD) are threaded onto a poly(ethylene glycol) chain capped with L-phenylalanine via ester linkages, were acetylated using acetic anhydride; alpha-CD release behavior was then characterized by in vitro hydrolysis. The degree of acetylation was changed by the concentration of acetic anhydride and the reaction time. The results of the in vitro hydrolysis indicate that the critical degree of acetylation to prolong supramolecular dissociation lies at around 30%. The terminal hydrolysis proceeded completely even with 100% of acetylation. These findings suggest that the hydrophobization of alpha-CDs in the polyrotaxane makes it possible to delay the time to complete the supramolecular dissociation. The hydrophobization of the polyrotaxane is of great importance for designing implantable materials that maintain their supramolecular structure until tissue regeneration with complete terminal hydrolysis.
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Affiliation(s)
- J Watanabe
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa
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24
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Hydrolytic degradation of PLA/PEO/PLA triblock copolymers prepared in the presence of Zn metal or CaH2. POLYMER 1998. [DOI: 10.1016/s0032-3861(97)10272-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Yeh MK, Davis SS, Coombes AG. Improving protein delivery from microparticles using blends of poly(DL lactide co-glycolide) and poly(ethylene oxide)-poly(propylene oxide) copolymers. Pharm Res 1996; 13:1693-8. [PMID: 8956336 DOI: 10.1023/a:1016496824839] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Microparticles containing ovalbumin as a model for protein drugs were formulated from blends of poly(DL lactide-co-glycolide) and poly(ethylene oxide)-poly(propylene oxide) copolymers (Pluronic). The objectives were to achieve uniform release characteristics and improved protein delivery capacity. METHODS The water- in oil -in oil emulsion/solvent extraction technique was used for microparticle production. RESULTS A protein loading level of over 40% (w/w) was attained in microparticles having a mean diameter of approximately 5 microns. Linear protein release profiles over 25 days in vitro were exhibited by certain blend formulations incorporating hydrophilic Pluronic F127. The release profile tended to plateau after 10 days when the more hydrophobic Pluronic L121 copolymer was used to prepare microparticles. A delivery capacity of 3 micrograms OVA/mg particles/ day was achieved by formulation of microparticles using a 1:2 blend of PLG:Pluronic F127. CONCLUSIONS The w/o/o formulation approach in combination with PLG:Pluronic blends shows potential for improving the delivery of therapeutic proteins and peptides from microparticulate systems. Novel vaccine formulations are also feasible by incorporation of Pluronic L121 in the microparticles as a co-adjuvant.
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Affiliation(s)
- M K Yeh
- Department of Pharmaceutical Sciences, University of Nottingham, University Park, United Kingdom
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26
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High molecular weight poly(l-lactide) and poly(ethylene oxide) blends: thermal characterization and physical properties. POLYMER 1996. [DOI: 10.1016/s0032-3861(96)00455-7] [Citation(s) in RCA: 407] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Improving the delivery capacity of microparticle systems using blends of poly(DL-lactide co-glycolide) and poly(ethylene glycol). J Control Release 1995. [DOI: 10.1016/0168-3659(95)00039-b] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Grijpma DW, Van Hofslot RDA, Supèr H, Nijenhuis AJ, Pennings AJ. Rubber toughening of poly(lactide) by blending and block copolymerization. POLYM ENG SCI 1994. [DOI: 10.1002/pen.760342205] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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29
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Coombes AG, Meikle MC. Resorbable synthetic polymers as replacements for bone graft. CLINICAL MATERIALS 1993; 17:35-67. [PMID: 10150176 DOI: 10.1016/0267-6605(94)90046-9] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The potential of resorbable synthetic polymers derived from the poly(alpha-hydroxy acids), poly(lactide) and poly(glycolide), to fulfill a role as bone graft substitutes is reviewed. The various elements of the relationship between the degradation behaviour of resorbable implants and polymer synthesis and chain structure, implant morphology, processing and dimensions have been defined. The production of resorbable polymeric implants has been extensively documented so as to provide a wide basis for selection of an appropriate manufacturing technique. The key requirement of implant dimensional stability over the early stages of bone healing is emphasised so as to provide a stable surface on which osteoblasts and/or their precursor cells may migrate and secrete bone matrix. Minimisation of the content of slow resorbing polymers such as poly(L-lactide) is recommended, consistent with retention of an adequate implant degradation characteristic. The review concludes with a summary of alternative resorbable polymers such as the polyphosphazines which are interesting candidate materials for bone repair and reconstruction.
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Affiliation(s)
- A G Coombes
- Department of Pharmaceutical Sciences, University of Nottingham, University Park, UK
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30
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Bae YH, Kim SW. Hydrogel delivery systems based on polymer blends, block co-polymers or interpenetrating networks. Adv Drug Deliv Rev 1993. [DOI: 10.1016/0169-409x(93)90029-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Cohn D, Elchai Z, Gershon B, Karck M, Lazarovici G, Sela J, Chandra M, Marom G, Uretzky G. Introducing a selectively biodegradable filament wound arterial prosthesis: a short-term implantation study. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1992; 26:1184-204. [PMID: 1429766 DOI: 10.1002/jbm.820260909] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This article introduces a new compliant and selectively biodegradable filament wound vascular graft and reports the findings of a short-term implantation study. A basic feature of filament winding is its ability to tailor and better control the mechanical properties of the prosthesis, so that a closer match with the anisotropic properties of native arteries is achieved. The elastomeric vascular grafts comprise poly(ether urethane urea) fibers (Lycra) embedded in a two-component matrix consisting of poly(ether urethane) (Pellethane) and a highly flexible poly(ethylene glycol)/poly(lactic acid) biodegradable segmented copolymer (PELA). Typical tensile modulus values fall in the few megapascals (MPa) range, this being comparable to that of natural arteries. The wound graft exhibits excellent handling and suturability characteristics as well as enhanced burst strength. Furthermore, due to its biodegradable constituent, the prosthesis combines minimal intraoperative blood loss and high healing porosity. The graft displays initially negligible in vitro water permeation, which increases gradually with time. In this short-term study, the prostheses were implanted in the canine carotid, and their biological performance was compared to that of expanded Gore-Tex. The luminal surface of the wound grafts was coated with a thin layer of pseudointima, strongly adhered to the prosthesis surface. Contrasting with the very stiff Gore-Tex grafts, the filament wound prostheses retained their high compliance, being highly pulsatile upon explanation. Histological studies fully corroborated these findings, underscoring the healing properties of these new filament wound vascular prostheses.
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Affiliation(s)
- D Cohn
- Casali Institute of Applied Chemistry, Graduate School of Applied Science and Technology, Hebrew University of Jerusalem, Israel
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32
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Coombes AG, Heckman JD. Gel casting of resorbable polymers. 2. In-vitro degradation of bone graft substitutes. Biomaterials 1992; 13:297-307. [PMID: 1600032 DOI: 10.1016/0142-9612(92)90053-q] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Gel cast microporous materials produced from: slow resorbing, poly(L-lactide); fast resorbing, 50:50 poly(DL lactide coglycolide); and blends of these polymers have been characterized by weight loss, compression testing and thermal analysis after immersion in phosphate buffered saline (37 degrees C, pH 7.4) for times up to 6 months. Increasing weight loss and reduction in compressive properties with immersion time were measured. Blending reduces the rate of weight loss and material shrinkage relative to the copolymer. Thermal analysis of degraded samples revealed evidence of reorganization of the crystalline phase in poly(L-lactide) and a crystalline component in the 50:50 copolymer, estimated at 5-7% of the original material content, which is probably responsible for gel formation. Thermograms of the blend are effectively a superposition of thermograms of the individual components. Gel casting shows potential for varying the resorption rate, form stability and compressive properties of micro/macroporous bone graft substitutes.
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Affiliation(s)
- A G Coombes
- Department of Orthopaedics, University of Texas, Health Science Centre, San Antonio 78284
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