301
|
Gilchrist SE, Rickard DL, Letchford K, Needham D, Burt HM. Phase separation behavior of fusidic acid and rifampicin in PLGA microspheres. Mol Pharm 2012; 9:1489-501. [PMID: 22482935 DOI: 10.1021/mp300099f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to characterize the phase separation behavior of fusidic acid (FA) and rifampicin (RIF) in poly(d,l-lactic acid-co-glycolic acid) (PLGA) using a model microsphere formulation. To accomplish this, microspheres containing 20% FA with 0%, 5%, 10%, 20%, and 30% RIF and 20% RIF with 30%, 20% 10%, 5%, and 0% FA were prepared by solvent evaporation. Drug-polymer and drug-drug compatibility and miscibility were characterized using laser confocal microscopy, Raman spectroscopy, XRPD, DSC, and real-time video recordings of single-microsphere formation. The encapsulation of FA and RIF alone, or in combination, results in a liquid-liquid phase separation of solvent-and-drug-rich microdomains that are excluded from the polymer bulk during microsphere hardening, resulting in amorphous spherical drug-rich domains within the polymer bulk and on the microsphere surface. FA and RIF phase separate from PLGA at relative droplet volumes of 0.311 ± 0.014 and 0.194 ± 0.000, respectively, predictive of the incompatibility of each drug and PLGA. When coloaded, FA and RIF phase separate in a single event at the relative droplet volume 0.251 ± 0.002, intermediate between each of the monoloaded formulations and dependent on the relative contribution of FA or RIF. The release of FA and RIF from phase-separated microspheres was characterized exclusively by a burst release and was dependent on the phase exclusion of surface drug-rich domains. Phase separation results in coalescence of drug-rich microdroplets and polymer phase exclusion, and it is dependent on the compatibility between FA and RIF and PLGA. FA and RIF are mutually miscible in all proportions as an amorphous glass, and they phase separate from the polymer as such. These drug-rich domains were excluded to the surface of the microspheres, and subsequent release of both drugs from the microspheres was rapid and reflected this surface location.
Collapse
Affiliation(s)
- Samuel E Gilchrist
- Faculty of Pharmaceutical Science, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | | | | | | |
Collapse
|
302
|
Zuo Q, Lu J, Hong A, Zhong D, Xie S, Liu Q, Huang Y, Shi Y, He L, Xue W. Preparation and characterization of PEM-coated alginate microgels for controlled release of protein. Biomed Mater 2012; 7:035012. [DOI: 10.1088/1748-6041/7/3/035012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
303
|
Zheng C, Liu X, Zhu J, Zhao Y. Preparation of cationic biodegradable dextran microspheres loaded with BSA and study on the mechanism of protein loading. Drug Dev Ind Pharm 2012; 38:653-8. [DOI: 10.3109/03639045.2011.589851] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
304
|
NIR-light triggered delivery of macromolecules into the cytosol. J Control Release 2012; 159:120-7. [DOI: 10.1016/j.jconrel.2011.12.013] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/14/2011] [Accepted: 12/17/2011] [Indexed: 12/21/2022]
|
305
|
Rastogi A, Bowman PD, Stavchansky S. Evaluation of a perforated drug delivery system in mice for prolonged and constant release of a hydrophilic drug. Drug Deliv Transl Res 2012; 2:106-11. [PMID: 25786719 DOI: 10.1007/s13346-012-0062-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A drug delivery system (DDS) consisting of a perforated microtube (polyimide, inside diameter = 1.8 mm, tube length = 20 mm, hole size = 0.15 mm) was characterized in vitro and in vivo for its usefulness for long-term release of hydrophilic drugs at a constant rate. Sodium fluorescein mixed with stearic acid was used as the model drug. The DDS was packed with sodium fluorescein and stearic acid in ratios of 50:50, 40:60, and 25:75, respectively, and in vitro drug release studies were performed in saline. Linear release rates with R (2) > 0.9700 were obtained for all groups. Release rates of 1,077.3 ± 264.6, 342.6 ± 146.4, and 14.4 ± 7.0 μg/day for sodium fluorescein were obtained from the three groups, respectively. After monitoring the in vitro release of fluorescein for 11 days, 7 tubes from the 40:60 group were implanted subcutaneously in each individual mice to study the in vivo release of fluorescein from the tubes by measuring the fluorescein in the urine for 84 days. An initial rapid release during the first 4 days was followed by a near zero order fluorescence from the tubes (R (2) = 0.9870). Following completion of the study, the DDSs were retrieved for histology. Morphological analysis indicated no clinical adverse reaction at the site of device implantation specific to the device. The DDS was found to be biocompatible and capable of long-term constant release of a hydrophilic drug such as sodium fluorescein.
Collapse
Affiliation(s)
- Ashish Rastogi
- US Army Institute of Surgical Research, San Antonio, TX, 78234, USA,
| | | | | |
Collapse
|
306
|
Ungaro F, d' Angelo I, Miro A, La Rotonda MI, Quaglia F. Engineered PLGA nano- and micro-carriers for pulmonary delivery: challenges and promises. J Pharm Pharmacol 2012; 64:1217-35. [DOI: 10.1111/j.2042-7158.2012.01486.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abstract
Objectives
The aim of this review is to summarize the current state-of-the-art in poly(lactic-co-glycolic acid) (PLGA) carriers for inhalation. It presents the rational of use, the potential and the recent advances in developing PLGA microparticles and nanoparticles for pulmonary delivery. The most promising particle engineering strategies are discussed, highlighting the advantages along with the major challenges for researchers working in this field.
Key findings
Biodegradable polymer carriers, such as PLGA particles, may permit effective protection and long-term delivery of the inhaled drug and, when adequately engineered, its efficient transport to the target. The carrier can be designed for inhalation on the basis of several strategies through the adequate combination of available particle technologies and excipients. In so doing, the properties of PLGA particles can be finely tuned at micro-size and nano-size level to fulfill specific therapeutic needs. This means not only to realize optimal in vitro/in vivo lung deposition of the formulation, which is still crucial, but also to control the fate of the drug in the lung after particle landing.
Summary
Although many challenges still exist, PLGA carriers may be highly beneficial and present a new scenario for patients suffering from chronic lung diseases and for pharmaceutical companies working to develop novel inhaled products.
Collapse
Affiliation(s)
- Francesca Ungaro
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Via D. Montesano, Naples, Italy
| | - Ivana d' Angelo
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Via D. Montesano, Naples, Italy
| | - Agnese Miro
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Via D. Montesano, Naples, Italy
| | - Maria I La Rotonda
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Via D. Montesano, Naples, Italy
| | - Fabiana Quaglia
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Via D. Montesano, Naples, Italy
| |
Collapse
|
307
|
Affiliation(s)
- Tina Vermonden
- Department of Pharmaceutics, Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
| | | | | |
Collapse
|
308
|
Trindade RA, Kiyohara PK, de Araujo PS, Bueno da Costa MH. PLGA microspheres containing bee venom proteins for preventive immunotherapy. Int J Pharm 2012; 423:124-33. [DOI: 10.1016/j.ijpharm.2011.02.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 02/15/2011] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
|
309
|
Recombinant spider silk particles for controlled delivery of protein drugs. Biomaterials 2012; 33:1554-62. [DOI: 10.1016/j.biomaterials.2011.10.053] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/20/2011] [Indexed: 11/19/2022]
|
310
|
Nelson DM, Ma Z, Leeson CE, Wagner WR. Extended and sequential delivery of protein from injectable thermoresponsive hydrogels. J Biomed Mater Res A 2012; 100:776-85. [PMID: 22237975 DOI: 10.1002/jbm.a.34015] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/12/2011] [Accepted: 10/25/2011] [Indexed: 11/10/2022]
Abstract
Thermoresponsive hydrogels are attractive for their injectability and retention in tissue sites where they may serve as a mechanical support and as a scaffold to guide tissue remodeling. Our objective in this report was to develop a thermoresponsive, biodegradable hydrogel system that would be capable of protein release from two distinct reservoirs--one where protein was attached to the hydrogel backbone, and one where protein was loaded into biodegradable microparticles mixed into the network. Thermoresponsive hydrogels consisting of N-isopropylacrylamide (NIPAAm), 2-hydroxyethyl methacrylate (HEMA), and biodegradable methacrylate polylactide were synthesized along with modified copolymers incorporating 1 mol % protein-reactive methacryloxy N-hydroxysuccinimide (MANHS), hydrophilic acrylic acid (AAc), or both. In vitro bovine serum albumin (BSA) release was studied from hydrogels, poly(lactide-co-glycolide) microparticles, or microparticles mixed into the hydrogels. The synthesized copolymers were able to gel below 37°C and release protein in excess of 3 months. The presence of MANHS and AAc in the copolymers was associated with higher loaded protein retention during thermal transition (45% vs. 22%) and faster release (2 months), respectively. Microspheres entrapped in the hydrogel released protein in a delayed fashion relative to microspheres in saline. The combination of a protein-reactive hydrogel mixed with protein-loaded microspheres demonstrated a sequential release of specific BSA populations. Overall the described drug delivery system combines the advantages of injectability, degradability, extended release, and sequential release, which may be useful in tissue engineering applications.
Collapse
Affiliation(s)
- Devin M Nelson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
| | | | | | | |
Collapse
|
311
|
Jin Z, Harvey AM, Mailloux S, Halámek J, Bocharova V, Twiss MR, Katz E. Electrochemically stimulated release of lysozyme from an alginate matrix cross-linked with iron cations. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm32008h] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
312
|
Moebus K, Siepmann J, Bodmeier R. Cubic phase-forming dry powders for controlled drug delivery on mucosal surfaces. J Control Release 2012; 157:206-15. [DOI: 10.1016/j.jconrel.2011.09.075] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 09/13/2011] [Accepted: 09/15/2011] [Indexed: 10/17/2022]
|
313
|
Moebus K, Siepmann J, Bodmeier R. Novel preparation techniques for alginate-poloxamer microparticles controlling protein release on mucosal surfaces. Eur J Pharm Sci 2011; 45:358-66. [PMID: 22178531 DOI: 10.1016/j.ejps.2011.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 11/22/2011] [Accepted: 12/02/2011] [Indexed: 11/30/2022]
Abstract
The objective of this study was to develop novel preparation techniques for protein-loaded, controlled release alginate-poloxamer microparticles with a size range suitable for pulmonary administration. Bovine serum albumin (BSA)-loaded microparticles were prepared by spray-drying aqueous polymer-drug solutions, followed by cross-linking the particles in aqueous or ethanolic CaCl(2) or aqueous ZnSO(4) solutions. The microparticles were characterized with respect to their morphology (optical and scanning electron microscopy), particle size (laser light diffraction), calcium content (atom absorption spectroscopy), alginate content (complexation with 1,9-dimethyl methylene blue) and in vitro drug release (modified Franz diffusion cell). The spray-dried microparticles were spherical in shape with a size range of 4-6μm. Aqueous cross-linking led to a significant size increase (10-15μm), whereas ethanolic cross-linking did not. The substantial drug loss (∼50%) during aqueous CaCl(2) cross-linking could be avoided by using aqueous ZnSO(4) or ethanolic CaCl(2) solutions. Protein release from microparticles cross-linked with ethanolic CaCl(2) solutions was much faster than in the case of aqueous CaCl(2) solutions, probably due to the lower calcium content. The salt concentration and temperature of the cross-linking solutions also affected the composition of and drug release from the microparticles. Cross-linked alginate-poloxamer microparticles can be produced in a size range appropriate for deep lung delivery and with controlled protein release kinetics (time frame: hours to days) with these novel preparation techniques. The systems offer an interesting potential for the controlled mucosal delivery of protein drugs.
Collapse
Affiliation(s)
- Katrin Moebus
- College of Pharmacy, Freie Universität Berlin, Kelchstrasse 31, 12169 Berlin, Germany
| | | | | |
Collapse
|
314
|
Wang Q, Wang W, Wu J, Wang A. Effect of attapulgite contents on release behaviors of a pH sensitive carboxymethyl cellulose-g-poly(acrylic acid)/attapulgite/sodium alginate composite hydrogel bead containing diclofenac. J Appl Polym Sci 2011. [DOI: 10.1002/app.35440] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
315
|
Checa-Casalengua P, Jiang C, Bravo-Osuna I, Tucker BA, Molina-Martínez IT, Young MJ, Herrero-Vanrell R. Retinal ganglion cells survival in a glaucoma model by GDNF/Vit E PLGA microspheres prepared according to a novel microencapsulation procedure. J Control Release 2011; 156:92-100. [DOI: 10.1016/j.jconrel.2011.06.023] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 06/05/2011] [Accepted: 06/10/2011] [Indexed: 10/18/2022]
|
316
|
Abstract
Whilst oral vaccination is a potentially preferred route in terms of patient adherence and mass vaccination, the ability to formulate effective oral vaccines remains a challenge. The primary barrier to oral vaccination is effective delivery of the vaccine through the GI tract owing to the many obstacles it presents, including low pH, enzyme degradation and bile-salt solubilization, which can result in breakdown/deactivation of a vaccine. For effective immune responses after oral administration, particulates need to be taken up by the M cells however, these are few in number. To enhance M-cell uptake, particle characteristics can be optimized with particle size, surface charge, targeting groups and bioadhesive properties all being considerations. Yet improved uptake may not translate into enhanced immune responses and formulating particulates with inherent adjuvant properties can offer advantages. Within this article, we establish the options available for consideration when building effective oral particulate vaccines.
Collapse
|
317
|
Wu J, Liao C, Wang Z, Cheng W, Zhou N, Wang S, Wan Y. Chitosan–polycaprolactone microspheres as carriers for delivering glial cell line-derived neurotrophic factor. REACT FUNCT POLYM 2011. [DOI: 10.1016/j.reactfunctpolym.2011.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
318
|
Preparation of Protein-Loaded Poly(L-Lactide) Microspheres by Solution-Enhanced Dispersion by Supercritical CO 2. ACTA ACUST UNITED AC 2011. [DOI: 10.4028/www.scientific.net/jbbte.11.93] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
SiO2-hemoglobin-poly(L-lactide) (SiO2-Hb-PLLA) microspheres were prepared in a process of solution-enhanced dispersion by supercritical CO2 (SEDS). SiO2 nanoparticles were loaded with Hb by adsorption firstly and then the Hb-SiO2 nanoparticles were further coated with PLLA by the SEDS process. The resulted microcapsules were characterized by scanning electron microscope (SEM), laser diffraction particle size analyser and Fourier transform infrared spectrometer (FTIR). The drug release profiles were also determined. The Hb-SiO2-PLLA microspheres have a narrow particle size distribution (PDI 0.189) with a mean particle size of 897nm and a drug loading of 7.1%. After coating with PLLA, the drug release from SiO2-Hb-PLLA showed a sustained process mainly in zero-order kinetics; only 3.7% drug was released in the first 24 hours, versus 51.9% for those without coating, which revealed that the coating of PLLA significantly retarded the drug release. The results also indicate that the SEDS process is a typical physical process to produce protein-loaded polymer microspheres without changing the molecular structure of proteins, which is potential in the application of designing proteins drug delivery system.
Collapse
|
319
|
Álvarez AL, Espinar FO, Méndez JB. The Application of Microencapsulation Techniques in the Treatment of Endodontic and Periodontal Diseases. Pharmaceutics 2011; 3:538-71. [PMID: 24310596 PMCID: PMC3857082 DOI: 10.3390/pharmaceutics3030538] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/09/2011] [Accepted: 08/24/2011] [Indexed: 11/12/2022] Open
Abstract
In the treatment of intracanal and periodontal infections, the local application of antibiotics and other therapeutic agents in the root canal or in periodontal pockets may be a promising approach to achieve sustained drug release, high antimicrobial activity and low systemic side effects. Microparticles made from biodegradable polymers have been reported to be an effective means of delivering antibacterial drugs in endodontic and periodontal therapy. The aim of this review article is to assess recent therapeutic strategies in which biocompatible microparticles are used for effective management of periodontal and endodontic diseases. In vitro and in vivo studies that have investigated the biocompatibility or efficacy of certain microparticle formulations and devices are presented. Future directions in the application of microencapsulation techniques in endodontic and periodontal therapies are discussed.
Collapse
Affiliation(s)
- Asteria Luzardo Álvarez
- Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Ciencias, Universidad de Santiago de Compostela, 27002 Lugo, Spain; E-Mail:
| | - Francisco Otero Espinar
- Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain; E-Mail:
| | - José Blanco Méndez
- Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Ciencias, Universidad de Santiago de Compostela, 27002 Lugo, Spain; E-Mail:
- Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain; E-Mail:
| |
Collapse
|
320
|
Jung YS, Na K. Protein Delivery System based on Various Polysaccharides. JOURNAL OF PHARMACEUTICAL INVESTIGATION 2011. [DOI: 10.4333/kps.2011.41.4.197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
|
321
|
Tafaghodi M, Eskandari M, Khamesipour A, Jaafari MR. Alginate microspheres encapsulated with autoclaved Leishmania major (ALM) and CpG-ODN induced partial protection and enhanced immune response against murine model of leishmaniasis. Exp Parasitol 2011; 129:107-14. [PMID: 21767536 DOI: 10.1016/j.exppara.2011.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 07/02/2011] [Accepted: 07/04/2011] [Indexed: 10/18/2022]
Abstract
A suitable adjuvant and delivery system are needed to enhance efficacy of vaccines against leishmaniasis. In this study, alginate microspheres as an antigen delivery system and CpG-ODN as an immunoadjuvant were used to enhance immune response and induce protection against an experimental autoclaved Leishmania major (ALM) vaccine. Alginate microspheres were prepared by an emulsification technique and the characteristics of the preparation such as size, encapsulation efficiency and release profile of encapsulates were studied. Mean diameter of microspheres was determined using SEM (Scanning Electron Microscopy) and particle size analyzer. The encapsulation efficiency was determined using Lowry protein assay method. The integrity of ALM antigens was assessed using SDS-PAGE. Mean diameter of microspheres was 1.8±1.0μm. BALB/c mice were immunized three times in 3-weeks intervals with ALM+CpG-ODN loaded microspheres [(ALM+CpG)(ALG)], ALM encapsulated alginate microspheres [(ALM)(ALG)], (ALM)(ALG)+CpG, ALM+CpG, ALM alone or PBS. The intensity of infection induced by L. major challenge was assessed by measuring size of footpad swelling. The strongest protection was observed in group of mice immunized with (ALM+CpG)(ALG). The groups of mice received (ALM+CpG)(ALG), (ALM)(ALG)+CpG, (ALM)(ALG) and ALM+CpG were also showed a significantly (P<0.05) smaller footpad swelling compared with the group that received either ALM alone or PBS. The mice immunized with (ALM+CpG)(ALG) or ALM+CpG showed the significantly (P<0.05) highest IgG2a/IgG1 ratio. The IFN-γ level was significantly (P<0.0001) highest in group of mice immunized with either (ALM)(ALG)+CpG or ALM+CpG. It is concluded that alginate microspheres and CpG-ODN adjuvant when are used simultaneously induced protection and enhanced immune response against ALM antigen.
Collapse
Affiliation(s)
- Mohsen Tafaghodi
- Nanotechnology Research Center, Pharmaceutical Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | | | | |
Collapse
|
322
|
Hwang JY, Choy YB, Seo SM, Park JH. Fabrication of Biodegradable Disc-shaped Microparticles with Micropattern using a Hot Embossing Process with Porous Microparticles. JOURNAL OF PHARMACEUTICAL INVESTIGATION 2011. [DOI: 10.4333/kps.2011.41.3.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
323
|
Reisacher WR, Liotta D, Yazdi S, Putnam D. Desensitizing mice to ovalbumin through subcutaneous microsphere immunotherapy (SMITH). Int Forum Allergy Rhinol 2011; 1:390-5. [DOI: 10.1002/alr.20074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 02/03/2011] [Accepted: 05/01/2011] [Indexed: 11/09/2022]
|
324
|
Performance of biodegradable microcapsules of poly(butylene succinate), poly(butylene succinate-co-adipate) and poly(butylene terephthalate-co-adipate) as drug encapsulation systems. Colloids Surf B Biointerfaces 2011; 84:498-507. [DOI: 10.1016/j.colsurfb.2011.02.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 01/14/2011] [Accepted: 02/01/2011] [Indexed: 01/16/2023]
|
325
|
The use of poly(D,L-lactic-co-glycolic) acid microspheres in the treatment of allergic disease. Curr Opin Otolaryngol Head Neck Surg 2011; 19:188-92. [DOI: 10.1097/moo.0b013e328345013a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
326
|
Integrity characterization of myoglobin released from poly(ε-caprolactone) microspheres using two analytical methods: UV/Vis spectrometry and conductometric bi-enzymatic biosensor. Eur J Pharm Biopharm 2011; 78:298-305. [DOI: 10.1016/j.ejpb.2011.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 12/17/2010] [Accepted: 01/25/2011] [Indexed: 11/21/2022]
|
327
|
In vivo fluorescence imaging of exogenous enzyme activity in the gastrointestinal tract. Proc Natl Acad Sci U S A 2011; 108:9032-7. [PMID: 21576491 DOI: 10.1073/pnas.1100285108] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Exogenous enzymes are administered orally to treat several diseases, such as pancreatic insufficiency and lactose intolerance. Due to the proteinaceous nature of enzymes, they are subject to inactivation and/or digestion in the gastrointestinal (GI) tract. Here we describe a convenient fluorescence-based assay to monitor the activity of therapeutic enzymes in real time in vivo in the GI tract. To establish the proof of principle, the assay was applied to proline-specific endopeptidases (PEPs), a group of enzymes recently proposed as adjuvant therapy for celiac disease (a highly prevalent immunogenetic enteropathy). A short PEP-specific peptide sequence which is part of larger immunotoxic sequences of gluten was labeled with a fluorescent dye and a corresponding quencher. Upon enzymatic cleavage, the fluorescence emission was dequenched and detected with an in vivo imaging system. PEPs originating from Flavobacterium meningosepticum (FM) and Myxococcus xanthus (MX) were evaluated after oral administration in rats. While MX PEP could not cleave the peptide in the stomach, FM PEP showed significant gastric activity reaching 40-60% of the maximal in vivo signal intensity. However, both enzymes produced comparable fluorescence signals in the small intestine. Coadministration of an antacid drug significantly enhanced MX PEP's gastric activity due to increased pH and/or inhibition of stomach proteases. With this simple procedure, differences in the in vivo performance of PEPs, which could not be identified under in vitro conditions, were detected. This imaging assay could be used to study other oral enzymes in vivo and therefore be instrumental in improving their therapeutic efficiency.
Collapse
|
328
|
Karal-Yılmaz O, Serhatlı M, Baysal K, Baysal BM. Preparation and in vitro characterization of vascular endothelial growth factor (VEGF)-loaded poly(D,L-lactic-co-glycolic acid) microspheres using a double emulsion/solvent evaporation technique. J Microencapsul 2011; 28:46-54. [PMID: 21171816 DOI: 10.3109/02652048.2010.523795] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Biodegradable Poly(lactic-co-glycolic acid; PLGA), microspheres encapsulating the angiogenic protein recombinant human vascular endothelial growth factor (rhVEGF) were formed to achieve VEGF release in a sustained manner. These microspheres are a promising delivery system which can be used for therapeutic angiogenesis. The PLGA microspheres incorporating two different initial loading amounts of rhVEGF have been prepared by a modified water-in-oil-in-water (w/o/w) double emulsion/solvent evaporation technique. The microspheres have been characterized by particle size distribution, environmental scanning electron microscopy (ESEM), light microscopy, encapsulation efficiency and their degradation was studied in vitro. The rhVEGF released from microspheres was quantified by the competitive enzyme-linked immunosorbent assay (ELISA) and human umbilical vein endothelial cell (HUVEC) proliferation assay was used to assess biological activity of the released VEGF. The microspheres were spherical with diameters of 10-60 µm and the encapsulation efficiency was between 46% and 60%. The release kinetics of rhVEGF was studied for two different amounts: 5 µg VEGF (V5) and 50 µg VEGF (V50) per 500 mg starting polymer. The total protein (VEGF:BSA) release increased up to 4 weeks for two rhVEGF concentrations. The ELISA results showed that the burst release for V5 and V50 microspheres were 4 and 27 ng/mL, respectively. For V5, the microspheres showed an initial burst release, followed by a higher steady-state release until 14 days. VEGF release increased up to 2 weeks for V50 microsphere. HUVEC proliferation assay showed that endothelial cells responded to bioactive VEGF by proliferating and migrating.
Collapse
Affiliation(s)
- Okşan Karal-Yılmaz
- TUBITAK, Marmara Research Center, Genetic Engineering and Biotechnology Institute, P.O. Box 21, 41470 Gebze-Kocaeli, Turkey.
| | | | | | | |
Collapse
|
329
|
Andreas K, Zehbe R, Kazubek M, Grzeschik K, Sternberg N, Bäumler H, Schubert H, Sittinger M, Ringe J. Biodegradable insulin-loaded PLGA microspheres fabricated by three different emulsification techniques: investigation for cartilage tissue engineering. Acta Biomater 2011; 7:1485-95. [PMID: 21168535 DOI: 10.1016/j.actbio.2010.12.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 11/17/2010] [Accepted: 12/13/2010] [Indexed: 01/02/2023]
Abstract
Growth, differentiation and migration factors facilitate the engineering of tissues but need to be administered with defined gradients over a prolonged period of time. In this study insulin as a growth factor for cartilage tissue engineering and a biodegradable PLGA delivery device were used. The aim was to investigate comparatively three different microencapsulation techniques, solid-in-oil-in-water (s/o/w), water-in-oil-in-water (w/o/w) and oil-in-oil-in-water (o/o/w), for the fabrication of insulin-loaded PLGA microspheres with regard to protein loading efficiency, release and degradation kinetics, biological activity of the released protein and phagocytosis of the microspheres. Insulin-loaded PLGA microspheres prepared by all three emulsification techniques had smooth and spherical surfaces with a negative zeta potential. The preparation technique did not affect particle degradation nor induce phagocytosis by human leukocytes. The delivery of structurally intact and biologically active insulin from the microspheres was shown using circular dichroism spectroscopy and a MCF7 cell-based proliferation assay. However, the insulin loading efficiency (w/o/w about 80%, s/o/w 60%, and o/o/w 25%) and the insulin release kinetics were influenced by the microencapsulation technique. The results demonstrate that the w/o/w microspheres are most appropriate, providing a high encapsulation efficiency and low initial burst release, and thus these were finally used for cartilage tissue engineering. Insulin released from w/o/w PLGA microspheres stimulated the formation of cartilage considerably in chondrocyte high density pellet cultures, as determined by increased secretion of proteoglycans and collagen type II. Our results should encourage further studies applying protein-loaded PLGA microspheres in combination with cell transplants or cell-free in situ tissue engineering implants to regenerate cartilage.
Collapse
Affiliation(s)
- Kristin Andreas
- Berlin-Brandenburg Center for Regenerative Therapies, Department of Rheumatology and Clinical Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
330
|
|
331
|
Temperature and pH dual-responsive cross-linked polymeric nanocapsules with controllable structures via surface-initiated atom transfer radical polymerization from templates. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2011; 7:789-96. [PMID: 21419869 DOI: 10.1016/j.nano.2011.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 12/01/2010] [Accepted: 02/16/2011] [Indexed: 11/24/2022]
Abstract
UNLABELLED Novel intelligent nanocapsules with temperature-responsive cross-linked polymer shells and pH-responsive polymer brushes on their inner walls were designed by the "polymerization from template" strategy via the surface-initiated atom transfer radical polymerization (SI-ATRP) technique using silica nanoparticles as the templates. The two-step sequential SI-ATRP procedures provided poly(tert-butyl acrylate) brushes on the inner walls of temperature-responsive cross-linked poly(N-isopropyl acrylamide) shells. Then the tert-butyl ester groups in the nanocapsules were transformed chemically into acrylic acid groups after the silica templates had been etched with hydrofluoric acid. The hollow structures and the multiple environmental stimuli-responsive properties were validated with transmission electron microscopy and dynamic light scattering techniques, respectively. In the strategy developed, the inner diameter, the cross-linking degree and the thickness of the shells, and the length of the functional brushes could be controlled by adjusting the preparation conditions. FROM THE CLINICAL EDITOR This basic science paper discusses the synthesis and functions of novel intelligent nanocapsules with temperature-responsive cross-linked polymer shells and pH-responsive polymer brushes on their inner walls.
Collapse
|
332
|
Li Z, Li L, Liu Y, Zhang H, Li X, Luo F, Mei X. Development of interferon alpha-2b microspheres with constant release. Int J Pharm 2011; 410:48-53. [PMID: 21419205 DOI: 10.1016/j.ijpharm.2011.03.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 03/01/2011] [Accepted: 03/10/2011] [Indexed: 11/30/2022]
Abstract
Interferon alpha-2b (IFNα-2b) is an important immune regulator used widely in clinic. However, frequent subcutaneous injection and substantial toxicity decrease patients' compliance. So, drug delivery with more precisely controlled drug release is urgent for IFNα-2b. Microsphere is a promising sustained drug delivery system, which has been studied widely for delivery of proteins. However, it was found difficult to keep proteins' activity and guarantee complete release. In this study, we solidified IFNα-2b as microparticles firstly by co-lyophilizing it with gelatin and ZnSO(4). Microspheres were then prepared. The preparing procedure and formulation were optimized with encapsulation efficiency and in vitro release as main parameters. Finally, the microspheres were prepared by S/O/W method with microparticle size about 5 μm and PEGT/PBT-PLGA (9:1, w/w) as matrix material. The diameter of microspheres was 28.94 μm, the encapsulation efficiency was 86.01%, the burst release was 16.69%, the cumulative release was 83.06% at 23th day, and IFNα-2b was released from microspheres with a zero-order profile. These microspheres also demonstrated sustained and steady release for about 13 days in rats. In conclusion, the procedure and formulation used in this study were supposed to be successful to keep IFNα-2b active and released constantly and completely.
Collapse
Affiliation(s)
- Zhiping Li
- Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Haidian District, Beijing 100850, China
| | | | | | | | | | | | | |
Collapse
|
333
|
Fu H, Rahaman MN, Day DE, Brown RF. Hollow hydroxyapatite microspheres as a device for controlled delivery of proteins. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2011; 22:579-91. [PMID: 21290170 PMCID: PMC3160344 DOI: 10.1007/s10856-011-4250-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 01/23/2011] [Indexed: 05/22/2023]
Abstract
Hollow hydroxyapatite (HA) microspheres were prepared by reacting solid microspheres of Li(2)O-CaO-B(2)O(3) glass (106-150 μm) in K(2)HPO(4) solution, and evaluated as a controlled delivery device for a model protein, bovine serum albumin (BSA). Reaction of the glass microspheres for 2 days in 0.02 M K(2)HPO(4) solution (pH = 9) at 37°C resulted in the formation of biocompatible HA microspheres with a hollow core diameter equal to 0.6 the external diameter, high surface area (~100 m(2)/g), and a mesoporous shell wall (pore size ≈ 13 nm). After loading with a solution of BSA in phosphate-buffered saline (PBS) (5 mg BSA/ml), the release kinetics of BSA from the HA microspheres into a PBS medium were measured using a micro bicinchoninic acid (BCA) protein assay. Release of BSA initially increased linearly with time, but almost ceased after 24-48 h. Modification of the BSA release kinetics was achieved by modifying the microstructure of the as-prepared HA microspheres using a controlled heat treatment (1-24 h at 600-900°C). Sustained release of BSA was achieved over 7-14 days from HA microspheres heated for 5 h at 600°C. The amount of BSA released at a given time was dependent on the concentration of BSA initially loaded into the HA microspheres. These hollow HA microspheres could provide a novel inorganic device for controlled local delivery of proteins and drugs.
Collapse
Affiliation(s)
- Hailuo Fu
- Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA. Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Mohamed N. Rahaman
- Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA. Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Delbert E. Day
- Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA. Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - Roger F. Brown
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65409, USA. Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, Rolla, MO 65409, USA
| |
Collapse
|
334
|
Chen Y, Zhou S, Li Q. Mathematical modeling of degradation for bulk-erosive polymers: applications in tissue engineering scaffolds and drug delivery systems. Acta Biomater 2011; 7:1140-9. [PMID: 20937415 DOI: 10.1016/j.actbio.2010.09.038] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/07/2010] [Accepted: 09/28/2010] [Indexed: 11/19/2022]
Abstract
The degradation of polymeric biomaterials, which are widely exploited in tissue engineering and drug delivery systems, has drawn significant attention in recent years. This paper aims to develop a mathematical model that combines stochastic hydrolysis and mass transport to simulate the polymeric degradation and erosion process. The hydrolysis reaction is modeled in a discrete fashion by a fundamental stochastic process and an additional autocatalytic effect induced by the local carboxylic acid concentration in terms of the continuous diffusion equation. Illustrative examples of microparticles and tissue scaffolds demonstrate the applicability of the model. It is found that diffusive transport plays a critical role in determining the degradation pathway, whilst autocatalysis makes the degradation size dependent. The modeling results show good agreement with experimental data in the literature, in which the hydrolysis rate, polymer architecture and matrix size actually work together to determine the characteristics of the degradation and erosion processes of bulk-erosive polymer devices. The proposed degradation model exhibits great potential for the design optimization of drug carriers and tissue scaffolds.
Collapse
Affiliation(s)
- Yuhang Chen
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, NSW 2006, Australia
| | | | | |
Collapse
|
335
|
Lee M, Bae H, Lee S, Chung NO, Lee H, Choi S, Hwang S, Lee J. Freezing/thawing processing of PVA in the preparation of structured microspheres for protein drug delivery. Macromol Res 2011. [DOI: 10.1007/s13233-011-0203-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
336
|
LoPresti C, Vetri V, Ricca M, Foderà V, Tripodo G, Spadaro G, Dispenza C. Pulsatile protein release and protection using radiation-crosslinked polypeptide hydrogel delivery devices. REACT FUNCT POLYM 2011. [DOI: 10.1016/j.reactfunctpolym.2010.11.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
337
|
Hu J, Ma PX. Nano-fibrous tissue engineering scaffolds capable of growth factor delivery. Pharm Res 2011; 28:1273-81. [PMID: 21234657 DOI: 10.1007/s11095-011-0367-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/06/2011] [Indexed: 01/18/2023]
Abstract
Tissue engineering aims at constructing biological substitutes to repair damaged tissues. Three-dimensional (3D) porous scaffolds are commonly utilized to define the 3D geometry of tissue engineering constructs and provide adequate pore space and surface to support cell attachment, migration, proliferation, differentiation and neo tissue genesis. Biomimetic 3D scaffolds provide synthetic microenvironments that mimic the natural regeneration microenvironments and promote tissue regeneration process. While nano-fibrous (NF) scaffolds are constructed to mimic the architecture of NF extracellular matrix, controlled-release growth factors are incorporated to modulate the regeneration process. The present article summarizes current advances in methods to fabricate NF polymer scaffolds and the technologies to incorporate controlled growth factor delivery systems into 3D scaffolds, followed by examples of accelerated regeneration when the scaffolds with growth factor releasing capacity are applied in animal models.
Collapse
Affiliation(s)
- Jiang Hu
- Department of Biologic and Materials Sciences, The University of Michigan, 1011 North University Ave, Room 2211, Ann Arbor, Michigan 48109-1078, USA
| | | |
Collapse
|
338
|
Guziewicz N, Best A, Perez-Ramirez B, Kaplan DL. Lyophilized silk fibroin hydrogels for the sustained local delivery of therapeutic monoclonal antibodies. Biomaterials 2011; 32:2642-50. [PMID: 21216004 DOI: 10.1016/j.biomaterials.2010.12.023] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Accepted: 12/14/2010] [Indexed: 01/09/2023]
Abstract
The development of sustained delivery systems compatible with protein therapeutics continues to be a significant unmet need. A lyophilized silk fibroin hydrogel matrix (lyogel) for the sustained release of pharmaceutically relevant monoclonal antibodies is described. Sonication of silk fibroin prior to antibody incorporation avoids exposing the antibody to the sol-gel transition inducing shear stress. Fourier Transform Infrared (FTIR) analysis showed no change in silk structural composition between hydrogel and lyogel or with increasing silk fibroin concentration. Antibody release from hydrogels occurred rapidly over 10 days regardless of silk concentration. Upon lyophilization, sustained antibody release was observed over 38 days from lyogels containing 6.2% (w/w) silk fibroin and above. In 3.2% (w/w) silk lyogels, antibody release was comparable to hydrogels. Swelling properties of lyogels followed a similar threshold behavior. Lyogels at 3.2% (w/w) silk recovered approximately 90% of their fluid mass upon rehydration, while approximately 50% fluid recovery was observed at 6.2% (w/w) silk and above. Antibody release was primarily governed by hydrophobic/hydrophilic silk-antibody interactions and secondarily altered by the hydration resistance of the lyogel. Hydration resistance was controlled by altering β-sheet (crystalline) density of the matrix. The antibody released from lyogels maintained biological activity. Silk lyogels offer an advantage as a delivery matrix over other hydrogel materials for the slow release of the loaded protein, making lyogels suitable for long-term sustained release applications.
Collapse
Affiliation(s)
- Nicholas Guziewicz
- BioFormulations Development, Genzyme Corporation, 1 Mountain Road, P.O. Box 9322, Framingham, MA 01701-9322, USA
| | | | | | | |
Collapse
|
339
|
Rothstein SN, Little SR. A “tool box” for rational design of degradable controlled release formulations. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm01668c] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
340
|
Wang M, Feng Q, Guo X, She Z, Tan R. A dual microsphere based on PLGA and chitosan for delivering the oligopeptide derived from BMP-2. Polym Degrad Stab 2011. [DOI: 10.1016/j.polymdegradstab.2010.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
341
|
Theiler S, Diamantouros SE, Jockenhoevel S, Keul H, Moeller M. Synthesis and characterization of biodegradable polyester/polyether resins via Michael-type addition. Polym Chem 2011. [DOI: 10.1039/c1py00262g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
|
342
|
Rudra A, Santra K, Mukherjee B. Poly [D, L-lactide-co-glycolide] Microspheres as a Delivery System of Protein Ovalbumin Used as a Model Protein Drug. ACTA ACUST UNITED AC 2011. [DOI: 10.3923/tasr.2011.47.56] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
343
|
Ma J, Qian K, Huang W, Zhu Y, Yang Q. Facile One-Step Synthesis of Double-Shelled CeO2Hollow Spheres and Their Optical and Catalytic Properties. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2010. [DOI: 10.1246/bcsj.20100144] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
344
|
Immunization against leishmaniasis by PLGA nanospheres encapsulated with autoclaved Leishmania major (ALM) and CpG-ODN. Parasitol Res 2010; 108:1265-73. [PMID: 21125294 DOI: 10.1007/s00436-010-2176-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 11/17/2010] [Indexed: 10/18/2022]
Abstract
Various adjuvants and delivery systems have been evaluated for increasing the protective immune responses against leishmaniasis and mostly have been shown not to be effective enough. In this study, poly(D,L-lactide-co-glycolide) (PLGA) nanospheres as an antigen delivery system and CpG-ODN as an immunoadjuvant have been used for the first time to enhance the immune response against autoclaved Leishmania major (ALM). PLGA nanospheres were prepared by a double-emulsion (W/O/W) technique. Particulate characteristics were studied by scanning electron microscopy and particle size analysis. Mean diameter of ALM + CpG-ODN-loaded nanospheres was 300 ± 128 nm. BALB/c mice were immunized three times in 3-week intervals using ALM plus CpG-ODN-loaded nanospheres [(ALM + CpG-ODN)(PLGA)], ALM encapsulated PLGA nanospheres [(ALM)(PLGA)], (ALM)(PLGA) + CpG, ALM + CpG, ALM alone, or phosphate buffer solution (PBS). The intensity of infection induced by L. major challenge was assessed by measuring size of footpad swelling. The strongest protection, showed by significantly (P<0.05) smaller footpad, was observed in mice immunized with (ALM + CpG-ODN)(PLGA). The (ALM)(PLGA), (ALM)(PLGA) + CpG, and ALM + CpG were also showed a significantly (P<0.05) smaller footpad swelling compared to the groups received either PBS or ALM alone. The mice immunized with (ALM + CpG-ODN)(PLGA), (ALM)(PLGA) + CpG, and ALM + CpG showed the highest IgG2a/IgG1 ratio, interferon-γ production, and lowest interleukin-4 production compared to the other groups. It is concluded that when both PLGA nanospheres and CpG-ODN adjuvants were used simultaneously, it induce stronger immune response and enhance protection rate against Leishmania infection.
Collapse
|
345
|
Jiang Y, Shi K, Wang S, Li X, Cui F. A morphological screening of protein crystals for interferon delivery by metal ion-chelate technology. Drug Dev Ind Pharm 2010; 36:1389-97. [DOI: 10.3109/03639045.2010.481303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
346
|
Fu H, Rahaman MN, Day DE. Effect of Process Variables on the Microstructure of Hollow Hydroxyapatite Microspheres Prepared by a Glass Conversion Method. JOURNAL OF THE AMERICAN CERAMIC SOCIETY. AMERICAN CERAMIC SOCIETY 2010; 93:3116-3123. [PMID: 21892226 PMCID: PMC3164324 DOI: 10.1111/j.1551-2916.2010.03833.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Solid microspheres (diameter = 106-150 μm) of a Li(2)O-CaO-B(2)O(3) glass were reacted in a K(2)HPO(4) solution to form hollow hydroxyapatite (HA) microspheres. The effect of the temperature (25°-60°C), K(2)HPO(4) concentration (0.01-0.25M), and pH (9-12) of the solution on the diameter (d) of the hollow core normalized to the diameter (D) of the HA microspheres, the surface area, and the pore size of the microsphere wall was studied. The statistically significant process variables that influenced these microstructural characteristics were evaluated using a factorial design approach. While the pH had little effect, the concentration of the solution had a marked effect on d/D, surface area, and pore size, whereas temperature markedly influenced d/D and pore size, but not the surface area. The largest hollow core size (d/D value ≈ 0.6) was obtained at the lowest temperature (25°C) or the lowest K(2)HPO(4) concentration (0.02M), while microspheres with the highest surface area (140 m(2)/g), with pores of size 10-12 nm were obtained at the highest concentration (0.25M). The consequences of these results for potential application of these hollow HA microspheres as devices for local delivery of proteins, such as drugs or growth factors, are discussed.
Collapse
|
347
|
Lu Q, Wang X, Hu X, Cebe P, Omenetto F, Kaplan DL. Stabilization and release of enzymes from silk films. Macromol Biosci 2010; 10:359-68. [PMID: 20217856 DOI: 10.1002/mabi.200900388] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A significant challenge remains to protect protein drugs from inactivation during production, storage, and use. In the present study, the stabilization and release of horseradish peroxidase (HRP) in silk films was investigated. Water-insoluble silk films were prepared under mild aqueous conditions, maintaining the activity of the entrapped enzyme. Depending on film processing and post-processing conditions, HRP retained more than 90% of the initial activity at 4 degrees C, room temperature and 37 degrees C over two months. The stability of protein drugs in silk films is attributed to intermolecular interactions between the silk and the enzymes, based on Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The unique structural feature of silk molecules, periodic hydrophobic-hydrophilic domains, enabled strong interactions with proteins. The entrapped protein was present in two states, untrapped active and trapped inactive forms. The ratio between the two forms varied according to processing conditions. Proteolytic degradation and dissolution of the silk films resulted in the release of the bound enzyme which was otherwise not released by diffusion; enzyme recovered full activity upon release. There was a linear relationship between silk degradation/dissolution and the release of entrapped enzyme. Modifying the secondary structure of the silk matrix and the interactions with the non-crystalline domains resulted in control of the film degradation or dissolution rate, and therefore the release rate of the entrapped enzyme. Based on the above results, silk materials are an intriguing carrier for proteins in terms of both retention of activity and controllable release kinetics from the films.
Collapse
Affiliation(s)
- Qiang Lu
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, USA
| | | | | | | | | | | |
Collapse
|
348
|
|
349
|
Duan B, Wang M. Encapsulation and release of biomolecules from Ca–P/PHBV nanocomposite microspheres and three-dimensional scaffolds fabricated by selective laser sintering. Polym Degrad Stab 2010. [DOI: 10.1016/j.polymdegradstab.2010.05.022] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
350
|
Mu B, Liu P, Pu Q. A functional cross linked polymeric nanocapsule with pH-responsive brushes on its inner wall: Preparation, characterization and controlled release. REACT FUNCT POLYM 2010. [DOI: 10.1016/j.reactfunctpolym.2010.05.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|