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Abulateefeh SR, Alkawareek MY, Alkilany AM. Tunable sustained release drug delivery system based on mononuclear aqueous core-polymer shell microcapsules. Int J Pharm 2019; 558:291-298. [PMID: 30641178 DOI: 10.1016/j.ijpharm.2019.01.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 01/23/2023]
Abstract
Poly(d,l-lactide-co-glycolide) (PLGA) and poly(d,l-lactide) (PLA) polymers were used successfully in the preparation of polymer shell microcapsules with mononuclear aqueous cores by the internal phase separation method. These microcapsules were prepared with varying amounts of polymer and water and loaded with fluorescein sodium as a model water soluble drug. Evaluation of drug loading and encapsulation efficiency reveals an optimum polymer to water ratio of around 1:3. Prepared PLGA and PLA microcapsules exhibit sustained drug release over 7 and 49 days, respectively. Drug release from both microcapsule types follow zero order kinetics over the first 90% release. Further tuning of release rate is found possible by preparing microcapsules with mixtures of PLGA and PLA polymers at varying ratios. These results suggest that aqueous core-PLGA and PLA microcapsules would be promising platforms for a wide range of sustained drug delivery systems for many hydrophilic drugs.
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2
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Sarett SM, Nelson CE, Duvall CL. Technologies for controlled, local delivery of siRNA. J Control Release 2015; 218:94-113. [PMID: 26476177 PMCID: PMC4665980 DOI: 10.1016/j.jconrel.2015.09.066] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/25/2015] [Accepted: 09/29/2015] [Indexed: 12/24/2022]
Abstract
The discovery of RNAi in the late 1990s unlocked a new realm of therapeutic possibilities by enabling potent and specific silencing of theoretically any desired genetic target. Better elucidation of the mechanism of action, the impact of chemical modifications that stabilize and reduce nonspecific effects of siRNA molecules, and the key design considerations for effective delivery systems has spurred progress toward developing clinically-successful siRNA therapies. A logical aim for initial siRNA translation is local therapies, as delivering siRNA directly to its site of action helps to ensure that a sufficient dose reaches the target tissue, lessens the potential for off-target side effects, and circumvents the substantial systemic delivery barriers. While locally injected or topically applied siRNA has progressed into numerous clinical trials, an enormous opportunity exists to develop sustained-release, local delivery systems that enable both spatial and temporal control of gene silencing. This review focuses on material platforms that establish both localized and controlled gene silencing, with emphasis on the systems that show most promise for clinical translation.
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Affiliation(s)
- Samantha M Sarett
- Vanderbilt University Department of Biomedical Engineering, United States
| | | | - Craig L Duvall
- Vanderbilt University Department of Biomedical Engineering, United States.
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3
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Giacalone G, Hillaireau H, Fattal E. Improving bioavailability and biodistribution of anti-HIV chemotherapy. Eur J Pharm Sci 2015; 75:40-53. [PMID: 25937367 DOI: 10.1016/j.ejps.2015.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/07/2015] [Accepted: 04/13/2015] [Indexed: 11/25/2022]
Abstract
In the context of the treatment of HIV/AIDS, many improvements have been achieved since the introduction of the combination therapy (HAART). Nevertheless, no cure for this disease has been so far possible, because of some particular features of the therapies. Among them, two important ones have been selected and will be the subject of this review. The first main concern in the treatments is the poor drug bioavailability, resulting in repeated administrations and therefore a demanding compliance (drug regimens consist of multiple drugs daily intake, and non-adherence to therapy is among the important reasons for treatment failure). A second important challenge is the need to target the drugs into the so-called reservoirs and sanctuaries, i.e. cells or body compartments where drugs cannot penetrate or are distributed in sub-active concentrations. The lack of antiviral action in these regions allows the virus to lie latent and start to replicate at any moment after therapy suspension. Recent drug delivery strategies addressing these two limitations will be presented in this review. In the first part, strategies to improve the bioavailability are proposed in order to overcome the absorption or the target cell barrier, or to extend the efficacy time of drugs. In the second section, the biodistribution issues are considered in order to target the drugs into the reservoirs and the sanctuaries, in particular the mononuclear phagocyte system and the brain.
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Affiliation(s)
- Giovanna Giacalone
- Institut Galien Paris-Sud, Université Paris-Sud, Faculté de Pharmacie, 5 rue J.-B. Clément, F-92290 Châtenay-Malabry, France; CNRS, UMR 8612, F-92290 Châtenay-Malabry, France.
| | - Hervé Hillaireau
- Institut Galien Paris-Sud, Université Paris-Sud, Faculté de Pharmacie, 5 rue J.-B. Clément, F-92290 Châtenay-Malabry, France; CNRS, UMR 8612, F-92290 Châtenay-Malabry, France.
| | - Elias Fattal
- Institut Galien Paris-Sud, Université Paris-Sud, Faculté de Pharmacie, 5 rue J.-B. Clément, F-92290 Châtenay-Malabry, France; CNRS, UMR 8612, F-92290 Châtenay-Malabry, France.
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4
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Patel B, Gupta N, Ahsan F. Particle engineering to enhance or lessen particle uptake by alveolar macrophages and to influence the therapeutic outcome. Eur J Pharm Biopharm 2015; 89:163-74. [DOI: 10.1016/j.ejpb.2014.12.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 11/26/2014] [Accepted: 12/02/2014] [Indexed: 12/23/2022]
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5
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Mannosylated chitosan nanoparticles for delivery of antisense oligonucleotides for macrophage targeting. BIOMED RESEARCH INTERNATIONAL 2014; 2014:526391. [PMID: 25057492 PMCID: PMC4098891 DOI: 10.1155/2014/526391] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 06/02/2014] [Indexed: 12/11/2022]
Abstract
The therapeutic potential of antisense oligonucleotides (ASODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study focuses on designing mannosylated low molecular weight (LMW) chitosan nanoconstructs for safe ODNs delivery by macrophage targeting. Mannose groups were coupled with LMW chitosan and characterized spectroscopically. Mannosylated chitosan ODN nanoparticles (MCHODN NPs) were formulated by self-assembled method using various N/P ratio (moles of amine groups of MCH to phosphate moieties of ODNs) and characterized for gel retardation assay, physicochemical characteristics, cytotoxicity and transfection efficiency, and antisense assay. Complete complexation of MCH/ODN was achieved at charge ratio of 1:1 and above. On increasing the N/P ratio of MCH/ODN, particle size of the NPs decreased whereas zeta potential (ZV) increased. MCHODN NPs displayed much higher transfection efficiency into Raw 264.7 cells (bears mannose receptors) than Hela cells and no significant toxicity was observed at all MCH concentrations. Antisense assay revealed that reduction in lipopolysaccharide (LPS) induced serum TNF-α is due to antisense activity of TJU-2755 ODN (sequence complementary to 3′-UTR of TNF-α). These results suggest that MCHODN NPs are acceptable choice to improve transfection efficiency in vitro and in vivo.
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6
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Uddin MN, Patel NJ, Bhowmik T, D'Souza B, Akalkotkar A, Etzlar F, Oettinger CW, D'Souza M. Enhanced bioavailability of orally administered antisense oligonucleotide to nuclear factor kappa B mRNA after microencapsulation with albumin. J Drug Target 2013; 21:450-7. [PMID: 23480723 DOI: 10.3109/1061186x.2013.765440] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Antisense molecules that pertain to ribonucleic acid (RNA) and complementary to the messenger RNA (mRNA) are produced by transcription of a given gene. Antisense oligonucleotides have emerged as potential gene-specific therapeutic agents that are currently undergoing evaluation in clinical trials for a variety of diseases. When administered orally, antisense oligionucleotides have poor bioavailability as they are rapidly degraded by the acid in the stomach and by the enzymes in the intestine. Therefore, the enhancement of bioavailability after oral administration is highly desirable. This article shows the enhanced bioavailability of antisense oligonucleotides that targets nuclear factor kappa B (NF-κB) mRNA after encapsulating in an inert, biodegradable albumin polymer matrix that was administered via the oral route into a rat model. The bioavailability of the antisense oligonucleotides to NF-κB in microencapsulated form was compared to the solution form of the drug upon oral administration. The solution form had a low bioavailability of 9%, whereas the bioavailability for the microencapsulated form of the drug increased up to 70%. Moreover, the other pharmacokinetic parameters including half-life (t1/2) and volume of distribution (Vd) increased for the microencapsulated form compared to the solution form of the drug.
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7
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Hu L, Zhang H, Song W. An overview of preparation and evaluation sustained-release injectable microspheres. J Microencapsul 2012; 30:369-82. [DOI: 10.3109/02652048.2012.742158] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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8
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Monaghan M, Pandit A. RNA interference therapy via functionalized scaffolds. Adv Drug Deliv Rev 2011; 63:197-208. [PMID: 21241760 DOI: 10.1016/j.addr.2011.01.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 12/16/2010] [Accepted: 01/05/2011] [Indexed: 12/27/2022]
Abstract
Tissue engineering aims to provide structural and biomolecular cues to compromised tissues through scaffolds. An emerging biomolecular cue is that of RNA interference by which the expression of genes can be silenced through a potent endogenous pathway. Recombinant viral-based approaches in RNAi delivery exist; however non-viral strategies offer many opportunities to exploit this mechanism of regulation in a safer way. Current RNAi therapies in clinical trials are without a vector (naked) or have slightly modified structures. Modification of these molecules with efficient backbone moieties for improved stability and potency, protecting and buffering them with delivery vehicles, and using scaffolds as reservoirs of delivery is at the frontier of current research. However, to enable an efficient sustained therapeutic effect scaffolds have a potentially significant role to play. This review presents non-viral delivery of RNAi that have been attempted via tissue engineered scaffolds. For RNAi to have a clinical impact, it is imperative to evaluate optimal delivery systems to ensure that the efficacy of this promising technology can be maximized.
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Affiliation(s)
- Michael Monaghan
- Network of Excellence for Functional Biomaterials, National University of Ireland-Galway, Ireland
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Ahmed J, Varshney SK. Polylactides—Chemistry, Properties and Green Packaging Technology: A Review. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2011. [DOI: 10.1080/10942910903125284] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Rosensteel SM, Wilson RP, White SL, Ehrlich HP. COL1A1 oligodeoxynucleotides decoy: biochemical and morphologic effects in an acute wound repair model. Exp Mol Pathol 2010; 89:307-13. [PMID: 20647009 DOI: 10.1016/j.yexmp.2010.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 06/29/2010] [Accepted: 07/09/2010] [Indexed: 11/15/2022]
Abstract
Type I collagen is an integral component of granulation tissue and scar, that is highly dependent on TGFβ1, a member of a pro-fibrotic family of cytokines, for its promotion and deposition. Blocking COL1A1 gene transcription obstructs type I collagen synthesis, hindering the progress of granulation tissue deposition and fibrosis. Local injections of a double stranded oligodeoxynucleotide (dsODN) decoy, containing the TGFβ1 regulatory element that is located in the distal promoter of the COL1A1 gene, were investigated in a rat polyvinyl alcohol (PVA) sponge granulation tissue implant model. The effects on the granulation tissue deposition by dsODN decoy therapy were evaluated by the synthesis of types I and III collagens as well as ED-A (cellular) fibronectin. Fluorescently labeled dsODN was used to identify the distribution of the decoy molecules in the sponge implant relative to the observed histological effects. Morphological alterations in cells and changes in the organization of connective tissue were documented and evaluated. Collagen levels were reduced by half in implants treated with 10 nM dsODN decoy compared to scrambled dsODN-treated implants. Histologically, dsODN decoy treated implants had an increased cellular density without a corresponding increase in deposited connective tissue. Polarized light birefringence pattern of Sirius red-stained sections showed less collagen fibers accumulating between fibroblasts. The highest concentration of fluorescently labeled dsODN was identified within the interior margin of sponge implants, correlating to increased cellular density and an altered birefringence patterns. In conclusion, 10 nM dsODN decoy therapy reduced collagen deposition and altered the organization of granulation tissue, supporting its potential as a localized anti-fibrotic therapy for limiting fibrotic conditions.
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Affiliation(s)
- Shawn M Rosensteel
- Department of Comparative Medicine, The Pennsylvania State University, College of Medicine, Hershey, PA, USA.
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11
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Onoshita T, Shimizu Y, Yamaya N, Miyazaki M, Yokoyama M, Fujiwara N, Nakajima T, Makino K, Terada H, Haga M. The behavior of PLGA microspheres containing rifampicin in alveolar macrophages. Colloids Surf B Biointerfaces 2010; 76:151-7. [DOI: 10.1016/j.colsurfb.2009.10.036] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 10/16/2009] [Accepted: 10/16/2009] [Indexed: 10/20/2022]
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12
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Alexander LM, Pernagallo S, Livigni A, Sánchez-Martín RM, Brickman JM, Bradley M. Investigation of microsphere-mediated cellular delivery by chemical, microscopic and gene expression analysis. MOLECULAR BIOSYSTEMS 2009; 6:399-409. [PMID: 20094660 DOI: 10.1039/b914428e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Amino functionalized cross-linked polystyrene microspheres of well defined sizes (0.2-2 mum) have been prepared and shown to be efficient and controllable delivery devices, capable of transporting anything from small dye molecules to bulky proteins into cells. However, the specific mechanism of cellular entry is largely unknown and widely variant from study to study. As such, chemical, biological and microscopic methods are used to elucidate the mechanism of cellular uptake for polystyrene microspheres of 0.2, 0.5 and 2 mum in mouse melanoma cells. Uptake is found to be wholly unreliant upon energetic processes, while lysosomal and endosomal tracking agents failed to show co-localisation with lysosomes/endosomes, suggesting a non-endocytic uptake pathway. To further explore the consequences of microsphere uptake, gene expression profiling is used to determine if there is a transcriptional response to "beadfection" in both murine and human cells. None of the common transcriptional responses to enhanced endocytosis are observed in beadfected cells, further supporting a non-endocytic uptake mechanism. Furthermore, the microspheres are noted to have a limited interaction with cells at a transcriptional level, supporting them as a non-toxic delivery vehicle.
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Affiliation(s)
- Lois M Alexander
- Chemical Biology Section, School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, UK
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13
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Zhao X, Pan F, Holt CM, Lewis AL, Lu JR. Controlled delivery of antisense oligonucleotides: a brief review of current strategies. Expert Opin Drug Deliv 2009; 6:673-86. [PMID: 19552611 DOI: 10.1517/17425240902992894] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Antisense therapy has been investigated extensively over the past two decades, either experimentally for gene functional research or clinically as therapeutic agents owing to the conceptual simplicity, ease of design and low cost. The concept of this therapeutic approach is promising because short antisense oligonucleotides (ASOs) can be delivered into target cells for specific hybridisation with target mRNA, resulting in the inhibition of the expression of pathogenic genes. However, the efficient delivery of the ASO molecules into target cells remains challenging; this bottleneck together with several other technical hurdles need to be overcome before this approach becomes effective and widely adopted. A variety of vectors such as lipids, polymers, peptides and nanoparticles have been explored. This review outlines the recent advances of the non-viral ASO delivery strategies. Several recent scientific studies, including authors' contributions, have been selected to highlight the technical aspects of ASO delivery.
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Affiliation(s)
- Xiubo Zhao
- University of Manchester, School of Physics and Astronomy, Biological Physics Group, Schuster Building, Manchester M13 9PL, UK.
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14
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Fattal E, Barratt G. Nanotechnologies and controlled release systems for the delivery of antisense oligonucleotides and small interfering RNA. Br J Pharmacol 2009; 157:179-94. [PMID: 19366348 DOI: 10.1111/j.1476-5381.2009.00148.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Antisense oligonucleotides and small interfering RNA have enormous potential for the treatment of a number of diseases, including cancer. However, several impediments to their widespread use as drugs still have to be overcome: in particular their lack of stability in physiological fluids and their poor penetration into cells. Association with or encapsulation within nano- and microsized drug delivery systems could help to solve these problems. In this review, we describe the progress that has been made using delivery systems composed of natural or synthetic polymers in the form of complexes, nanoparticles or microparticles.
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Affiliation(s)
- Elias Fattal
- Univ Paris Sud 11, UMR 8612, Châtenay-Malabry, F-92290, France
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15
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Akhavein N, Oettinger CW, Gayakwad SG, Addo RT, Bejugam NK, Bauer JD, Do D, Pollock SH, D'souza MJ. Treatment of adjuvant arthritis using microencapsulated antisense NF-κB oligonucleotides. J Microencapsul 2008; 26:223-34. [PMID: 18666015 DOI: 10.1080/02652040802268691] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Antisense oligonucleotides are promising new therapeutic agents used to selectively inhibit target genes such as Nuclear Factor Kappa B (NF-κB), an important transcription factor in the pathogenesis of inflammatory disease. The purpose of the present study was to evaluate microencapsulated antisense oligonucleotides specific to NF-κB for in vitro efficacy and treatment of adjuvant-induced arthritis in rats. Oligonucleotide-loaded albumin microspheres were prepared and characterized in terms of size, zeta potential, morphology and release pattern. This study reports significant NF-κB inhibition in vitro after treatment with microencapsulated antisense oligonucleotides. Furthermore, microencapsulated antisense NF-κB oligonucleotides were found to inhibit paw inflammation associated with rat adjuvant-induced arthritis in a dose-dependent manner. Taken together, the results presented in this work described albumin microspheres to be effective delivery vehicles for antisense NF-κB oligonucleotides and a potential treatment for inflammatory diseases.
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Affiliation(s)
- Nima Akhavein
- College of Pharmacy and Health Sciences, Mercer University, Atlanta, Georgia, USA.
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16
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Wei Q, Wei W, Tian R, Wang LY, Su ZG, Ma GH. Preparation of uniform-sized PELA microspheres with high encapsulation efficiency of antigen by premix membrane emulsification. J Colloid Interface Sci 2008; 323:267-73. [DOI: 10.1016/j.jcis.2008.04.058] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Revised: 04/17/2008] [Accepted: 04/19/2008] [Indexed: 11/28/2022]
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18
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Nanostructured microspheres produced by supercritical fluid extraction of emulsions. Biotechnol Bioeng 2008; 100:1020-33. [DOI: 10.1002/bit.21845] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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19
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Miao ZM, Cheng SX, Zhang XZ, Zhuo RX. Study on Drug Release Behaviors of Poly-α,β-[N-(2-hydroxyethyl)-l-aspartamide]-g-poly(ε-caprolactone) Nano- and Microparticles. Biomacromolecules 2006; 7:2020-6. [PMID: 16768428 DOI: 10.1021/bm060200o] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biodegradable amphiphilic graft copolymers poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide]-g-poly(epsilon-caprolactone) (PHEA-g-PCL) with different branch lengths were synthesized through the ring-opening polymerization of epsilon-caprolactone initiated by the macroinitiator PHEA bearing hydroxyl groups. With use of the graft copolymers with different compositions, nanoparticle drug delivery systems with sizes smaller than 100 nm were prepared by a dialysis method, and microparticle drug delivery systems with sizes smaller than 5 microm were fabricated by a melting-emulsion method. The regularly spherical shapes of the drug-loaded nano- and microparticles were verified by transmission electron microscopy and scanning electron microscopy. In vitro drug release properties of nano- and microparticle drug delivery systems were investigated, with the emphasis on the effects of polymer composition, particle size, and drug-loading content on the release behaviors.
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Affiliation(s)
- Zhi-Mei Miao
- Key Laboratory of Biomedical Polymers of Ministry of Education, Department of Chemistry, Wuhan University, Wuhan 430072, PR China
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20
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Abstract
Tumour specific drug targeting has been a very actively investigated area for over 2 decades. Various approaches have involved the use of drug delivery systems that can localise the anticancer agent at the tumour site without damaging the normal cells. For this purpose, various delivery systems that have been utilised are liposomes, microspheres and recently, nanoparticles. Two liposome formulations containing anticancer drugs for example, adriamycin and daunomycin are already on the market in the USA and Europe. Microspheres are also being investigated for delivering various anticancer drugs and protein/peptides for anticancer treatment, and several formulations are in Phase I/II clinical trials. Antitumour drugs have also been linked to tumour specific monoclonal antibodies via various chemical linkages. Doxorubicin was linked to a chimeric monoclonal antibody that was targeted to the Lewis Y antigen. Though this conjugate initially showed potential, it was recently dropped from Phase II clinical trials. Another approach with monoclonal antibodies has been the use of immunotoxins. Immunotoxins initially showed promise as potential anticancer agents at picomolar concentrations but several clinical and preclinical studies have not shown much promise in this regard. Drug containing liposomes and microspheres have been further linked to tumour specific monoclonal antibodies to enhance their tumour specificity. Most of the studies with immunoliposomes or targeted microspheres have not gone beyond the preclinical studies. New therapeutic approaches are presently emerging based on natural products like cytokines, peptide growth factor antagonists, antisense oligonucleotides and specific genes. These approaches need the help of delivery systems to deliver these complex molecules to tumour cells. One of the current pursued approaches is the use of cationic liposomes. Several clinical studies are undergoing with various cationic liposomes and the next few years will demonstrate the usefulness of this approach. In recent years, the problems in cancer treatment have been complicated with the emergence of resistance strains leading to resistant and cross-resistant tumour cells. Several agents have been used to overcome or reverse drug-resistance in solid tumours and it remains a highly pursued area in cancer treatment.
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Affiliation(s)
- M S Sachdeva
- College of Pharmacy, Florida A&M University, Tallahassee, FL 32307, USA
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21
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Grenha A, Seijo B, Remuñán-López C. Microencapsulated chitosan nanoparticles for lung protein delivery. Eur J Pharm Sci 2005; 25:427-37. [PMID: 15893461 DOI: 10.1016/j.ejps.2005.04.009] [Citation(s) in RCA: 283] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 03/17/2005] [Accepted: 04/09/2005] [Indexed: 10/25/2022]
Abstract
It has already been demonstrated that spray drying is a very valuable technique for producing dry powders adequate for pulmonary delivery of drugs. We have developed chitosan/tripolyphosphate nanoparticles that promote peptide absorption across mucosal surfaces. The aim of this work was to microencapsulate protein-loaded chitosan nanoparticles using typical aerosol excipients, such as mannitol and lactose, producing microspheres as carriers of protein-loaded nanoparticles to the lung. The results showed that the obtained microspheres are mostly spherical and possess appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters between 2 and 3 microm, apparent density lower than 0.45 g/cm3). Moreover, microspheres morphology was strongly affected by the content of chitosan nanoparticles. These nanoparticles show a good protein loading capacity (65-80%), providing the release of 75-80% insulin within 15 min, and can be easily recovered from microspheres after contact with an aqueous medium with no significant changes in their size and zeta potential values. Therefore, this work demonstrated that protein-loaded nanoparticles could be successfully incorporated into microspheres with adequate characteristics to reach the deep lung, which after contact with its aqueous environment are expected to be able to release the nanoparticles, and thus, the therapeutic macromolecule.
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Affiliation(s)
- Ana Grenha
- University of Santiago de Compostela, Pharmacy and Pharmaceutical Technology, 15782 Santiago de Compostela, Spain
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22
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Khan A, Benboubetra M, Sayyed PZ, Ng KW, Fox S, Beck G, Benter IF, Akhtar S. Sustained polymeric delivery of gene silencing antisense ODNs, siRNA, DNAzymes and ribozymes: in vitro and in vivo studies. J Drug Target 2005; 12:393-404. [PMID: 15545089 DOI: 10.1080/10611860400003858] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Small interfering RNA (siRNA), antisense oligonucleotides (ODNs), ribozymes and DNAzymes have emerged as sequence-specific inhibitors of gene expression that may have therapeutic potential in the treatment of a wide range of diseases. Due to their rapid degradation in vivo, the efficacy of naked gene silencing nucleic acids is relatively short lived. The entrapment of these nucleic acids within biodegradable sustained-release delivery systems may improve their stability and reduce the doses required for efficacy. In this study, we have evaluated the potential in vitro and in vivo use of biodegradable poly (D,L-lactide-co-glycolide) copolymer (PLGA) microspheres as sustained delivery devices for ODNs, ribozyme, siRNA and DNA enzymes. In addition, we investigated the release of ODN conjugates bearing 5'-end lipophilic groups. The in vitro sustained release profiles of microsphere-entrapped nucleic acids were dependent on variables such as the type of nucleic acid used, the nature of the lipophilic group, and whether the nucleic acid used was single or double stranded. For in vivo studies, whole body autoradiography was used to monitor the bio-distribution of either free tritium-labelled ODN or that entrapped within PLGA microspheres following subcutaneous administration in Balb-c mice. The majority of the radioactivity associated with free ODN was eliminated within 24 h whereas polymer-released ODN persisted in organs and at the site of administration even after seven days post-administration. Polymer microsphere released ODN exhibited a similar tissue and cellular tropism to the free ODN. Micro-autoradiography analyses of the liver and kidneys showed similar bio-distribution for polymer-released and free ODNs with the majority of radioactivity being concentrated in the proximal convoluted tubules of the kidney and in the Kupffer cells of the liver. These findings suggest that biodegradable PLGA microspheres offer a method for improving the in vivo sustained delivery of gene silencing nucleic acids, and hence are worthy of further investigation as delivery systems for these macromolecules.
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MESH Headings
- Animals
- Autoradiography
- DNA, Catalytic/administration & dosage
- DNA, Catalytic/chemistry
- Drug Delivery Systems
- Fluorouracil/administration & dosage
- Fluorouracil/pharmacokinetics
- Gene Silencing
- In Vitro Techniques
- Kidney/metabolism
- Lactic Acid/chemistry
- Liver/metabolism
- Mice
- Mice, Inbred BALB C
- Microspheres
- Oligonucleotides, Antisense/administration & dosage
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/pharmacokinetics
- Polyglycolic Acid/chemistry
- Polylactic Acid-Polyglycolic Acid Copolymer
- Polymers/chemistry
- RNA, Catalytic/administration & dosage
- RNA, Catalytic/chemistry
- RNA, Small Interfering/administration & dosage
- RNA, Small Interfering/chemistry
- Spleen/metabolism
- Time Factors
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Affiliation(s)
- Alim Khan
- Centre for Genome-based Therapeutics, The Welsh School of Pharmacy, Cardiff University, UK
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23
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Dinauer N, Lochmann D, Demirhan I, Bouazzaoui A, Zimmer A, Chandra A, Kreuter J, von Briesen H. Intracellular tracking of protamine/antisense oligonucleotide nanoparticles and their inhibitory effect on HIV-1 transactivation. J Control Release 2004; 96:497-507. [PMID: 15120905 DOI: 10.1016/j.jconrel.2004.02.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Accepted: 02/12/2004] [Indexed: 11/17/2022]
Abstract
Membrane transport of antisense oligonucleotides (ODN) is an inefficient process which requires special carriers for their intracellular delivery. We have developed a delivery system for AS-ODN and their phosphorothioate analogues (AS-PTO) directed against human immunodeficiency virus type 1 (HIV-1) tat mRNA for efficient transfection of HIV-1 target cells. Protamine was used to complex AS-ODN and AS-PTO to form nanoparticles with diameters of about 180 nm and surface charges in the range of -18 to +30 mV. Cellular uptake of these nanoparticles was significantly enhanced compared to naked oligonucleotides. A double labeling technique with fluorescently tagged protamine and AS-ODN was used to follow the intracellular fate of the nanoparticles. Protamine/AS-ODN nanoparticles showed release of the antisense compound leading to specific inhibition of tat mediated HIV-1 transactivation. In contrast, protamine/AS-PTO complexes were stable over 72 h, and failed to release AS-PTO. These results demonstrate that protamine/AS-ODN nanoparticles are useful for future therapeutical application to inhibit viral gene expression.
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MESH Headings
- Cell Survival/drug effects
- Gene Products, tat/chemistry
- Gene Products, tat/metabolism
- HIV-1/drug effects
- HIV-1/genetics
- Humans
- Jurkat Cells
- Light
- Microspheres
- Monocytes/drug effects
- Monocytes/metabolism
- Oligonucleotides, Antisense/administration & dosage
- Oligonucleotides, Antisense/pharmacokinetics
- Oligonucleotides, Antisense/pharmacology
- Particle Size
- Protamines/administration & dosage
- Protamines/pharmacokinetics
- Protamines/pharmacology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Scattering, Radiation
- Spectrometry, Fluorescence
- Surface Properties
- Transcriptional Activation/drug effects
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Norbert Dinauer
- Department of Virology and Cell Biology, Chemotherapeutisches Forschungsinstitut Georg-Speyer-Haus, Paul-Ehrlich-Strasse 42-44, D-60596 Frankfurt am Main, Germany
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24
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Ulusoy A, Onur MA. Measurement of in vitro phagocytic activity using functional groups carrying monodisperse poly(glycidyl methacrylate) microspheres in rat blood. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2004; 14:1299-310. [PMID: 14768915 DOI: 10.1163/156856203322553509] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phagocytic activity of monocyte and neutrophil leukocytes in rat blood was investigated using monodisperse poly(glycidyl methacrylate) (poly(GMA)) microspheres. Interactions of monocyte and neutrophil leukocytes with plain poly(GMA), charged poly(GMA)-NH2 and biomodified poly(GMA) (poly(GMA)-albumin and opsonized poly(GMA)) was studied as a function of time. Here we report the cellular phagocytosis rate of particles and the total internalised particle amount. Phagocytes showed higher phagocytic activity for poly(GMA) microspheres carrying functional groups versus plain poly(GMA) particles. Phagocytic activity was the highest for opsonized poly(GMA) microspheres (P < 0.05).
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Affiliation(s)
- Ayse Ulusoy
- Hacettepe University, Faculty of Science, Department of Biology, Ankara, Turkey.
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25
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Freiberg S, Zhu XX. Polymer microspheres for controlled drug release. Int J Pharm 2004; 282:1-18. [PMID: 15336378 DOI: 10.1016/j.ijpharm.2004.04.013] [Citation(s) in RCA: 810] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Revised: 04/21/2004] [Accepted: 04/22/2004] [Indexed: 11/25/2022]
Abstract
Polymer microspheres can be employed to deliver medication in a rate-controlled and sometimes targeted manner. Medication is released from a microsphere by drug leaching from the polymer or by degradation of the polymer matrix. Since the rate of drug release is controlled by these two factors, it is important to understand the physical and chemical properties of the releasing medium. This review presents the methods used in the preparation of microspheres from monomers or from linear polymers and discusses the physio-chemical properties that affect the formation, structure, and morphology of the spheres. Topics including the effects of molecular weight, blended spheres, crystallinity, drug distribution, porosity, and sphere size are discussed in relation to the characteristics of the release process. Added control over release profiles can be obtained by the employment of core-shell systems and pH-sensitive spheres; the enhancements presented by such systems are discussed through literature examples.
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Affiliation(s)
- S Freiberg
- Département de chimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, Que., H3C 3J7, Canada
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26
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Stern M, Ulrich K, Geddes DM, Alton EWFW. Poly (D, L-lactide-co-glycolide)/DNA microspheres to facilitate prolonged transgene expression in airway epithelium in vitro, ex vivo and in vivo. Gene Ther 2003; 10:1282-8. [PMID: 12883524 DOI: 10.1038/sj.gt.3301994] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Repeat administration of gene therapy for cystic fibrosis is likely to be essential for long-term clinical efficacy. This may be minimized by the use of slow-release gene transfer preparations with more prolonged expression and longer dosing intervals for the patient. Poly(D-L-lactide-co-glycolide) (PLG) is a biodegradable and biocompatible polymer that has been used to encapsulate plasmid DNA. PLG-DNA microspheres were generated and characterized with respect to morphology, size (80% of particles <5.2 microm), and encapsulation efficiency (50.7+/-2.3%, n=6). Gel electrophoresis of DNA re-extracted from the microspheres confirmed that despite a decrease in the proportion of supercoiled conformation, it had not been degraded by the preparation process. Gene transfer efficiency was tested using microspheres encapsulating the reporter gene beta-galactosidase in vitro on Cos 7 cells and a CF airway epithelial line (CFTEo approximately ) and ex vivo in a sheep tracheal (s.t.) model. In both cases, transgene expression was significantly (P<0.01) lower at the first time point tested (24 h in vitro, 48 h ex vivo) compared to lipid-#67-mediated gene transfer. However, PLG-mediated expression in vitro was sustained at 48 h, while lipid #67-mediated expression levels had dropped significantly (P<0.05) to 50.3+/-13.7 and 38.2+/-2.7% (Cos 7 and CFTEo approximately cells, respectively) of the 24-h level. This pattern was also seen in the s.t. model where at 72 h, PLG-mediated expression was 125.4+/-7.2% of the 48-h level demonstrating significantly (P<0.05) better retention of transfection efficiency than lipid #67, where levels had fallen to approximately half the 48 h level. By 96 h, expression was still retained in the PLG-transfected group (87.3+/-12.5% of 48 h expression) but was undetectable in the lipid -#67-transfected s.t. Finally, PLG microspheres, encapsulating the reporter gene chloramphenicol transferase (CAT, 80 microg) were instilled intranasally into Balb/C mice. Compared to lipid-#67-mediated delivery, where whole lung CAT expression was highest at 48 h (13.7 x 10(3)+/-0.05 CAT U/microg protein, n=6) and then not detectable at further time points, CAT expression was not detectable in PLG-transfected mice at 48 h, but was detectable at 7, 14 and 21 days after transfection. These data demonstrate that PLG-mediated gene transfer can produce prolonged gene expression in airway epithelia. However, gene transfer efficiency still requires significant improvement.
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Affiliation(s)
- M Stern
- Department of Gene Therapy, Imperial College Faculty of Medicine at the National Heart and Lung Institute, London, UK
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27
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Tondelli L, Canto E, Pistagna A, Butt S, Tripiciano A, Cortesi R, Sparnacci K, Laus M. Tailor-made core-shell nanospheres for antisense oligonucleotide delivery: IV. Adsorption/release behaviour. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2003; 12:1339-57. [PMID: 11922479 DOI: 10.1163/156856202753419268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The adsorption/release behaviour of oligodeoxynucleotides (ODNs) on double functional core-shell polymethylmethacrylate nanospheres, with a narrow size distribution, is described. The outer shell consists of alkyl or glycolic chains containing permanently-charged quaternary ammonium groups. Ion pair formation between negatively-charged ODN phosphate groups and positively-charged groups, present on the nanosphere surface, is the main mechanism of interaction. The amount of adsorbed ODN depends on both the ODN concentration and the nanosphere surface charge density. An adsorption-induced swelling mechanism is proposed in which a modification of the charged diffuse layer around the nanospheres increases the ODN binding site accessibility with increasing ODN concentration. Adsorption on the nanosphere surface prevents serum degradation of the ODNs. ODN release is negligible in the presence of culture medium but occurs gradually in the presence of serum. No significant cytotoxicity of the free nanoparticles was found in PBMC and CEM cells after 24 h at ODN concentrations required for antisense activity.
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28
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Study on biodegradable polymers: synthesis and characterization of poly(DL-lactic acid-co-l-lysine) random copolymer. Eur Polym J 2003. [DOI: 10.1016/s0014-3057(02)00354-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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29
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Jackson JK, Liang LS, Hunter WL, Reynolds M, Sandberg JA, Springate C, Burt HM. The encapsulation of ribozymes in biodegradable polymeric matrices. Int J Pharm 2002; 243:43-55. [PMID: 12176294 DOI: 10.1016/s0378-5173(02)00228-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ribozymes are catalytic RNA that bind and cleave specific regions of target RNA. Therefore, protein synthesis by the target RNA may be specifically inhibited by ribozymes. However, ribozymes are rapidly cleared from plasma so effective treatment of proliferative diseases may rely on the repeated administration of these agents to maintain therapeutic ribozyme concentrations. Therefore, the objective of this study was to encapsulate ribozymes in injectable polymeric paste and microsphere formulations to allow for the controlled release of these agents over extended periods of time. Ribozymes were effectively encapsulated in poly(L-lactic acid) (PLLA) and poly(lactic-co-glycolic) (PLGA) microspheres in various size ranges using a modified water-in-oil-in-water emulsion system and in poly(epsilon-caprolactone) (PCL) pastes by physical blending. These formulations released non-degraded ribozymes, in vitro, in a controlled manner. PLLA microspheres released the ribozymes rapidly whereas PLGA released drugs more slowly. The release rate of ribozymes from PCL pastes could be effectively controlled by altering the loading concentration of ribozymes in the paste. These polymeric injectable formulations of ribozymes may allow for the extended treatment of localized disease sites, such as cancer and arthritis, without the need for repeated dosing.
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Affiliation(s)
- John K Jackson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, 2146 East Mall, BC, Canada V6T 1Z3
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30
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Hussain M, Beale G, Hughes M, Akhtar S. Co-delivery of an antisense oligonucleotide and 5-fluorouracil using sustained release poly (lactide-co-glycolide) microsphere formulations for potential combination therapy in cancer. Int J Pharm 2002; 234:129-38. [PMID: 11839444 DOI: 10.1016/s0378-5173(01)00950-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Antisense oligonucleotides (AODNs) can selectively inhibit oncogene expression by Watson-Crick hybridisation to target mRNA and are being increasingly considered for use in combination with conventional drugs for potential anticancer therapy. Combination therapy of AODNs and cytotoxic agents using biodegradable polymeric delivery systems potentially offers several advantages including site-specific or organ-directed targeting, protection from digesting enzymes, and improved pharmacokinetics/pharmacodynamics resulting from sustained delivery of the entrapped drugs. Using a model AODN targeting the epidermal growth factor receptor (that is over-expressed in several cancers including breast and brain cancer) and the commonly used cytotoxic agent, 5-fluorouracil (5-FU), we have examined the use of poly (lactide-co-glycolide) (P(LA-GA)) microsphere formulations for co-delivery of these agents. Both agents were either co-entrapped in a single microsphere formulation or individually entrapped in two separate microsphere formulations and release profiles determined in vitro. Using a double emulsion method for preparing the P(LA-GA) microspheres suitable entrapment and sustained release over 35 days was observed in both types of formulation. Release of AODN and 5-FU from all formulations appeared to be biphasic. However, the release rates of the two agents were significantly slower when co-entrapped as a single microsphere formulation compared to those obtained with the separate formulations. Electrophoretic mobility shift assays suggested that this might be, in part, due to an interaction of 5-FU with the oligodeoxynucleotide (ODN). Further, our data suggest that by mixing individual formulations of 5-FU and ODNs at different mass ratios allowed greater flexibility in achieving the desired release profile as well as avoiding potential drug-drug interactions. Thus, co-administration of individual P(LA-GA) microsphere formulations of AODNs and 5-FU, at appropriate mass ratios, appears worthy of further investigation for the potential co-delivery of these anti-cancer agents in vivo.
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Affiliation(s)
- Majad Hussain
- Aston Centre for Gene-based Therapeutics (ACGT) Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET, UK
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31
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Chirila TV, Rakoczy PE, Garrett KL, Lou X, Constable IJ. The use of synthetic polymers for delivery of therapeutic antisense oligodeoxynucleotides. Biomaterials 2002; 23:321-42. [PMID: 11761152 PMCID: PMC7124374 DOI: 10.1016/s0142-9612(01)00125-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2000] [Accepted: 03/26/2001] [Indexed: 12/20/2022]
Abstract
Developed over the past two decades, the antisense strategy has become a technology of recognised therapeutic potential, and many of the problems raised earlier in its application have been solved to varying extents. However, the adequate delivery of antisense oligodeoxynucleotides to individual cells remains an important and inordinately difficult challenge. Synthetic polymers appeared on this scene in the middle 1980s, and there is a surprisingly large variety used or proposed so far as agents for delivery of oligodeoxynucleotides. After discussing the principles of antisense strategy, certain aspects of the ingestion of macromolecules by cells, and the present situation of delivery procedures, this article analyses in detail the attempts to use synthetic polymers as carrier matrices and or cell membrane permeabilisation agents for delivery of antisense oligodeoxynucleotides. Structural aspects of various polymers, as well as the results, promises and limitations of their use are critically evaluated.
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Key Words
- a, adenine
- as, antisense
- c, cytosine
- cd, cyclodextrin
- dna, deoxyribonucleic acid
- evac, poly(ethylene-co-vinyl acetate)
- g, guanine
- hart, hybrid-arrested translation
- help, high-efficiency liquid phase
- hema, 2-hydroxyethyl methacrylate
- hpma, n-(2-hydroxypropyl)methacrylamide
- ipec, interpolyelectrolyte complex
- odn, oligodeoxyribonucleotide, oligodeoxynucleotide
- pamam, polyamidoamines
- pca, polycyanoacrylates
- pdtema, n-[2-(2-pyridyldithio)]ethylmethacrylamide
- pedot, poly(3,4-ethylenedioxythiophene)
- peg, poly(ethylene glycol)
- pei, polyethyleneimine
- peo, poly(ethylene oxide)
- pga, poly(glycolic acid)
- pl, polylysine
- pla, poly(lactic acid)
- pll, poly(l-lysine)
- por, polyornithine
- ps, polyspermine
- rme, receptor-mediated endocytosis
- rna, ribonucleic acid
- mrna, messenger ribonucleic acid
- rnase, ribonuclease
- snaige, synthetic or small nucleic acids interfering with gene expression
- t, thymine
- vp, 1-vinyl-2-pyrrolidinone
- antisense strategy
- antisense oligodeoxynucleotides
- endocytosis
- drug delivery
- charged polymers
- neutral polymers
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Affiliation(s)
- Traian V Chirila
- Centre for Ophthalmology & Visual Science and Lions Eye Institute, University of Western Australia, Nedlands, Australia.
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32
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Khan A, Sommer W, Fuxe K, Akhtar S. Site-specific administration of antisense oligonucleotides using biodegradable polymer microspheres provides sustained delivery and improved subcellular biodistribution in the neostriatum of the rat brain. J Drug Target 2001; 8:319-34. [PMID: 11328659 DOI: 10.3109/10611860008997909] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Antisense oligonucleotides (ODNs) are being increasingly used in the central nervous system as biological tools, as drug-target validation agents and as potential therapeutic agents. Although the local delivery of naked ODNs to the brain can result in the desired biological effects, the duration of efficacy is relatively short lived due to the combined effects of rapid ODN degradation and elimination half-lives in vivo. In this study, we have examined the use of biodegradable polymer microspheres as a site-specific delivery system for targeting ODNs to the neostriatum of the rat brain. Model phosphorothioate backbone-modified ODNs were entrapped within poly(D,L-lactide-co-glycolide) (PLAGA) microspheres using a double emulsion-deposition method and the formulations characterised in terms of particle size, surface morphology, percent encapsulation efficiency, ODN loading and in vitro release profiles. For in vivo evaluation, PLAGA microspheres containing fluorescently-labelled ODNs were stereo-taxically administered to the neostriatum of the rat brain and biodistribution of ODNs monitored after 48 h. Administration of free fluorescently-labelled ODNs to the neostriatum resulted in a punctate cellular distribution of ODNs after 24 h with little or no ODN remaining in the neostriatum after 48 h. In comparison, fluorescently-labelled ODNs delivered using polymer microspheres were intensely visible in cells after 48 h post-administration and the fluorescence appeared to be diffuse covering both cytosolic and nuclear regions. Dual-label immunohistochemical analyses suggested that ODNs were mainly distributed to neuronal cells. These data indicate that site-specific administration of ODNs using biodegradable polymer microspheres will not only provide sustained delivery of nucleic acids but can also improve the cellular distribution of ODNs to brain cells. Sustained or controlled-release biodegradable polymer formulations, therefore, represent an attractive strategy for improved local delivery of ODNs to the CNS.
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Affiliation(s)
- A Khan
- Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET, UK
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33
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Berkland C, Kim K, Pack DW. Fabrication of PLG microspheres with precisely controlled and monodisperse size distributions. J Control Release 2001; 73:59-74. [PMID: 11337060 DOI: 10.1016/s0168-3659(01)00289-9] [Citation(s) in RCA: 272] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The size distribution of biodegradable polymer microspheres critically impacts the allowable routes of administration, biodistribution, and release rate of encapsulated compounds. We have developed a method for producing microspheres of precisely controlled and/or monodisperse size distributions. Our apparatus comprises spraying a polymer-containing solution through a nozzle with (i) acoustic excitation to produce uniform droplets, and (ii) an annular, non-solvent carrier stream allowing further control of the droplet size. We used this apparatus to fabricate poly(D,L-lactide-co-glycolide) (PLG) spheres. The acoustic excitation method, by itself, produced uniform microspheres as small as 30 microm in diameter in which > or =95% of the spheres were within 1.0-1.5 microm of the average. The carrier stream method alone allowed production of spheres as small as approximately 1-2 microm in diameter from a 100-microm diameter nozzle, but generated broader size distributions. By combining the two devices, we fabricated very uniform spheres with average diameters from approximately 5 to >500 microm. Furthermore, by discretely or continuously varying the experimental parameters, we fabricated microsphere populations with predefined size distributions. Finally, we demonstrate encapsulation and in vitro release of a model drug compound, rhodamine B. In summary, our apparatus provides unprecedented control of microsphere size and may allow development of advanced controlled-release delivery systems.
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Affiliation(s)
- C Berkland
- Department of Chemical Engineering, University of Illinois, Urbana, IL 61801, USA
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34
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Hughes MD, Hussain M, Nawaz Q, Sayyed P, Akhtar S. The cellular delivery of antisense oligonucleotides and ribozymes. Drug Discov Today 2001; 6:303-315. [PMID: 11257582 DOI: 10.1016/s1359-6446(00)00326-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The design and development of antisense oligonucleotides and ribozymes for the treatment of diseases arising from genetic abnormalities has become a real possibility over the past few years. Improvements in oligonucleotide chemistry have led to the synthesis of nucleic acids that are relatively stable in the biological milieu. However, advances in cellular targeting and intracellular delivery will probably lead to more widespread clinical applications. This review looks at recent advances in the in vitro and in vivo delivery of antisense oligodeoxynucleotides and ribozymes.
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Affiliation(s)
- M D. Hughes
- Aston Centre for Gene-based Therapeutics (ACGT), Pharmaceutical Sciences Research Institute, Aston University, Aston Triangle, B4 7ET, Birmingham, UK
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35
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Jain RA. The manufacturing techniques of various drug loaded biodegradable poly(lactide-co-glycolide) (PLGA) devices. Biomaterials 2000; 21:2475-90. [PMID: 11055295 DOI: 10.1016/s0142-9612(00)00115-0] [Citation(s) in RCA: 1375] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A considerable research has been conducted on drug delivery by biodegradable polymeric devices, following the entry of bioresorbable surgical sutures in the market about two decades ago. Amongst the different classes of biodegradable polymers, the thermoplastic aliphatic poly(esters) like poly(lactide) (PLA), poly(glycolide) (PGA), and especially the copolymer of lactide and glycolide, poly(lactide-co-glycolide) (PLGA) have generated immense interest due to their favorable properties such as good biocompatibility, biodegradability, and mechanical strength. Also, they are easy to formulate into different devices for carrying a variety of drug classes such as vaccines, peptides, proteins, and micromolecules. Also, they have been approved by the Food and Drug Administration (FDA) for drug delivery. This review discusses the various traditional and novel techniques (such as in situ microencapsulation) of preparing various drug loaded PLGA devices, with emphasis on preparing microparticles. Also, certain issues about other related biodegradable polyesters are discussed.
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Affiliation(s)
- R A Jain
- NanoSystems, a Division of Elan Pharmaceutical Technologies, King of Prussia, PA 19406, USA.
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36
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Akhtar S, Hughes MD, Khan A, Bibby M, Hussain M, Nawaz Q, Double J, Sayyed P. The delivery of antisense therapeutics. Adv Drug Deliv Rev 2000; 44:3-21. [PMID: 11035194 DOI: 10.1016/s0169-409x(00)00080-6] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Antisense oligonucleotides, ribozymes and DNAzymes have emerged as novel, highly selective inhibitors or modulators of gene expression. Indeed, their use in the treatment of diseases arising from genetic abnormalities has become a real possibility over the past few years. The first antisense drug molecule is now available for clinical use in Europe and USA. However, their successful application in the clinic will require improvements in cellular targeting and intracellular delivery. This review aims to look at recent advances in the in vitro and in vivo delivery of antisense oligodeoxynucleotides and ribozymes.
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Affiliation(s)
- S Akhtar
- Aston Centre for Gene-based Therapeutics (ACGT), Pharmaceutical Sciences Research Institute, Aston University, Aston Triangle, B4 7ET, Birmingham, UK
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37
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Freytag T, Dashevsky A, Tillman L, Hardee GE, Bodmeier R. Improvement of the encapsulation efficiency of oligonucleotide-containing biodegradable microspheres. J Control Release 2000; 69:197-207. [PMID: 11018557 DOI: 10.1016/s0168-3659(00)00299-6] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The objective of this study was to encapsulate an oligonucleotide drug within poly(lactide) microparticles with high encapsulation efficiencies at high theoretical drug loadings by the solvent evaporation method. With the conventional W/O/W method, the encapsulation efficiency decreased with increasing internal water content, increasing stirring time prior to filtration of the microparticles and increasing drug loading. The encapsulation was improved by replacing methylene chloride with ethyl acetate, by using micronized drug powder instead of an internal aqueous phase or by adding electrolytes or nonelectrolytes to the external phase. With ethyl acetate, a pre-emulsification step into a smaller volume of external aqueous phase was necessary in order to avoid premature polymer precipitation and to obtain microparticles. The addition of salts (NaCl or MgCl(2)) or sorbitol to the external aqueous phase significantly improved the encapsulation efficiency, even at high theoretical drug loadings. The microparticles had a denser structure with a smooth, pore-free surface.
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Affiliation(s)
- T Freytag
- College of Pharmacy, Freie Universität Berlin, Kelchstrasse 31, 12169 Berlin, Germany
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38
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Garcia-Chaumont C, Seksek O, Grzybowska J, Borowski E, Bolard J. Delivery systems for antisense oligonucleotides. Pharmacol Ther 2000; 87:255-77. [PMID: 11008003 DOI: 10.1016/s0163-7258(00)00062-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In vitro, the efficacy of the antisense approach is strongly increased by systems delivering oligodeoxyribonucleotides (ODNs) to cells. Up to now, most of the developed vectors favor ODN entrance by a mechanism based on endocytosis. Such is the case for particulate systems, including liposomes (cationic or non-cationic), cationic polyelectrolytes, and delivery systems targeted to specific receptors. Under these conditions, endosomal compartments may represent a dead end for ODNs. Current research attempts to develop conditions for escaping from these compartments. A new class of vectors acts by passive permeabilization of the plasma membrane. It includes peptides, streptolysin O, and cationic derivatives of polyene antibiotics. In vivo, the interest of a delivery system, up to now, has appeared limited. Development of vectors insensitive to the presence of serum seems to be a prerequisite for future improvements.
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Affiliation(s)
- C Garcia-Chaumont
- LPBC, CNRS ESA 7033, Université Pierre et Marie Curie, case 138, 4, place Jussieu, 75252 05, Paris cedex, France
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39
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Berton M, Allémann E, Stein CA, Gurny R. Highly loaded nanoparticulate carrier using an hydrophobic antisense oligonucleotide complex. Eur J Pharm Sci 1999; 9:163-70. [PMID: 10620729 DOI: 10.1016/s0928-0987(99)00049-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Antisense oligonucleotides, and particularly those with phosphorothioate backbones, have emerged as potential gene specific therapeutic agents and are currently undergoing evaluation in clinical trials for a variety of diseases. In the area of HIV-1 therapeutics, targeting of oligonucleotides to infected cells, such as macrophages, would be highly desirable. The present study was designed to prepare and characterize oligonucleotide-loaded nanoparticles for this purpose. Due to their hydrophilic characteristics, oligonucleotides are difficult to entrap in polymeric particles. Here, the oligonucleotides were first complexed with cetyltrimethylammonium bromide. The oligonucleotide-loaded nanoparticles were prepared by the emulsification-diffusion method and subsequently purified. In comparison with previous studies, a high oligonucleotide-loading was achieved; 2.5, 5 and 10% oligonucleotide loading were assessed. If the initial oligonucleotide content was 4%, this method produced a final oligonucleotide loading of 1.9% with an entrapment efficiency of 47%. The integrity of the oligonucleotide and of the polymer, in the final freeze-dried product, was retained.
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Affiliation(s)
- M Berton
- School of Pharmacy, University of Geneva, quai E.-Ansermet CH-1211, Geneva, Switzerland
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40
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Zimmer A. Antisense oligonucleotide delivery with polyhexylcyanoacrylate nanoparticles as carriers. Methods 1999; 18:286-95, 322. [PMID: 10454987 DOI: 10.1006/meth.1999.0786] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Polyalkylcyanoacrylate nanoparticles are effective colloidal drug carriers and were prepared by an emulsion polymerization process. Antisense oligonucleotides were loaded on the particles by adsorption. A cationic polymer, DEAE-dextran, was incorporated into the particle matrix or a cationic hydrophobic detergent (CTAB) was used to form a lipophilic oligonucleotide ion pair. Enzymatic digestion of the oligonucleotides was almost quantitatively inhibited by this nanoparticle complex and cellular uptake by different cell lines was significantly enhanced. In vivo the biodistribution of the oligonucleotide nanoparticle complex resulted in targeting of oligonucleotides to the liver. Improvements in antisense treatments with nanoparticles were demonstrated for tumor therapy as well as for antiviral applications.
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Affiliation(s)
- A Zimmer
- Biocenter, Institute for Pharmaceutical Technology, University of Frankfurt, Frankfurt am Main, Germany.
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Lewis KJ, Irwin WJ, Akhtar S. Development of a sustained-release biodegradable polymer delivery system for site-specific delivery of oligonucleotides: characterization of P(LA-GA) copolymer microspheres in vitro. J Drug Target 1998; 5:291-302. [PMID: 9713978 DOI: 10.3109/10611869808995882] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Development of a Sustained-Release Biodegradable Polymer Delivery System for Site-Specific Delivery of Oligonucleotides: Characterization of P(LA-GA) Copolymer Microspheres In Vitro Antisense oligodeoxynucleotides (ODNs) can selectively inhibit individual gene expression provided they gain access to and remain stable at the target site for a sufficient period of time. Biodegradable sustained-release delivery systems may facilitate site-specific delivery and also prevent degradation of ODNs by nucleases whilst delivering the nucleic acid in a controlled manner to the desired site of action. In this study, we have characterized biodegradable poly (lactide-co-glycolide) (P(LA-GA)) 50:50 microspheres for the potential delivery of antisense oligonucleotides in vivo. Phosphodiester (PO) oligonucleotides complementary to either c-myc proto-oncogene or the tat gene in HIV-RNA were adequately incorporated within P(LA-GA) microspheres with entrapment efficiencies up to 60% depending on particles size. In vitro release profiles of antisense nucleic acids from 10-20 microm size microspheres over 56 days in physiological buffer were triphasic. Profiles were characterised by an initial burst effect during the first 48 hours (phase 1) of release followed by a more sustained release (phase 2) with an additional increased release (phase 3) being observed after 25 days which corresponded with bulk degradation of the copolymer matrix. The release profiles were influenced by microsphere size, copolymer molecular weight, ODN loading, ODN length and by the pH of release medium used. The serum stability of PO ODNs was significantly improved when entrapped within P(LA-GA) microspheres and the hybridization capability, as assessed by duplex melting (Tm) measurements, of released ODN was not impaired by the double-emulsion microsphere fabrication procedure used. Thus, P(LA-GA) microspheres appear to be promising candidates for improving site-specific delivery profiles for ODNs and are worthy of further evaluation in vivo.
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Affiliation(s)
- K J Lewis
- Pharmaceutical Sciences Institute, Aston University, Birmingham, UK
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Akhtar S. Antisense technology: selection and delivery of optimally acting antisense oligonucleotides. J Drug Target 1998; 5:225-34. [PMID: 9713973 DOI: 10.3109/10611869808995877] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Jain R, Shah NH, Malick AW, Rhodes CT. Controlled drug delivery by biodegradable poly(ester) devices: different preparative approaches. Drug Dev Ind Pharm 1998; 24:703-27. [PMID: 9876519 DOI: 10.3109/03639049809082719] [Citation(s) in RCA: 191] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There has been extensive research on drug delivery by biodegradable polymeric devices since bioresorbable surgical sutures entered the market two decades ago. Among the different classes of biodegradable polymers, the thermoplastic aliphatic poly(esters) such as poly(lactide) (PLA), poly(glycolide) (PGA), and especially the copolymer of lactide and glycolide referred to as poly(lactide-co-glycolide) (PLGA) have generated tremendous interest because of their excellent biocompatibility, biodegradability, and mechanical strength. They are easy to formulate into various devices for carrying a variety of drug classes such as vaccines, peptides, proteins, and micromolecules. Most importantly, they have been approved by the United States Food and Drug Administration (FDA) for drug delivery. This review presents different preparation techniques of various drug-loaded PLGA devices, with special emphasis on preparing microparticles. Certain issues about other related biodegradable polyesters are discussed.
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Affiliation(s)
- R Jain
- Department of Applied Pharmaceutical Sciences, The University of Rhode Island, Kingston 02881, USA.
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Literature Alerts. J Microencapsul 1998. [DOI: 10.3109/02652049809006856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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46
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Meidan V, Dunnion D, Irwin W, Akhtar S. Effect of ultrasound on the stability of oligodeoxynucleotides in vitro. Int J Pharm 1997. [DOI: 10.1016/s0378-5173(97)04915-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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