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Palomar-Alonso N, Lee M, Kim M. Exosomes: Membrane-associated proteins, challenges and perspectives. Biochem Biophys Rep 2024; 37:101599. [PMID: 38145105 PMCID: PMC10746368 DOI: 10.1016/j.bbrep.2023.101599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/25/2023] [Accepted: 11/28/2023] [Indexed: 12/26/2023] Open
Abstract
Membrane proteins determine the precise function of each membrane and, therefore, the function of each cell type. These proteins essential roles in cell physiology, participating in the maintenance of the cell metabolism, its homeostasis or promoting proper cell growth. Membrane proteins, as has long been described, are located both in the plasma membrane and in complex subcellular structures. However, they can also be released into the extracellular environment associated with extracellular vesicles (EVs). To date, most of the research have been focused on understanding the role of exosomal RNA in several processes. Recently, there has been increasing interest in studying the function of exosome membrane proteins for exosome-based therapy, but not much research has been done yet on the function of exosome membrane proteins. One of the major limitations of studying exosome membrane proteins and their application to translational research of exosome-based therapeutics is the low yield of exosome isolation. Here, we have introduced a new perspective on exosome membrane protein research by reviewing studies showing the important role of exosome membrane proteins in exosome-based therapies. Furthermore, we have proposed a new strategy to boost the yield of exosome isolation: hybridization of liposomes with exosome-derived membrane. Liposomes have already been reported to affect the cell excitation to increase exosome production in tumor cells. Therefore, increasing cellular uptake of these liposomes would enhance exosome release by increasing cellular excitation. This new perspective could be a breakthrough in exosome-based therapeutic research.
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Affiliation(s)
- Nuria Palomar-Alonso
- Department of Neurology, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Mijung Lee
- Department of Neurology, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
| | - Manho Kim
- Department of Neurology, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
- Neuroscience Dementia Research Institute, Seoul National University College of Medicine, Seoul, South Korea
- Protein Metabolism Medical Research Center, College of Medicine, Seoul National University Hospital, Seoul, South Korea
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2
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Moholkar DN, Kandimalla R, Gupta RC, Aqil F. Advances in lipid-based carriers for cancer therapeutics: Liposomes, exosomes and hybrid exosomes. Cancer Lett 2023; 565:216220. [PMID: 37209944 DOI: 10.1016/j.canlet.2023.216220] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/18/2023] [Accepted: 05/06/2023] [Indexed: 05/22/2023]
Abstract
Cancer has recently surpassed heart disease as the leading cause of deaths worldwide for the age group 45-65 and has been the primary focus for biomedical researchers. Presently, the drugs involved in the first-line cancer therapy are raising concerns due to high toxicity and lack of selectivity to cancer cells. There has been a significant increase in research with innovative nano formulations to entrap the therapeutic payload to enhance efficacy and eliminate or minimize toxic effects. Lipid-based carriers stand out due to their unique structural properties and biocompatible nature. The two main leaders of lipid-based drug carriers: long known liposomes and comparatively new exosomes have been well-researched. The similarity between the two lipid-based carriers is the vesicular structure with the core's capability to carry the payload. While liposomes utilize chemically derived and altered phospholipid components, the exosomes are naturally occurring vesicles with inherent lipids, proteins, and nucleic acids. More recently, researchers have focused on developing hybrid exosomes by fusing liposomes and exosomes. Combining these two types of vesicles may offer some advantages such as high drug loading, targeted cellular uptake, biocompatibility, controlled release, stability in harsh conditions and low immunogenicity.
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Affiliation(s)
- Disha N Moholkar
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - Raghuram Kandimalla
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA; Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
| | - Ramesh C Gupta
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA; Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
| | - Farrukh Aqil
- Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA; Department of Medicine, University of Louisville, Louisville, KY, 40202, USA.
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3
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Guarro M, Suñer F, Lecina M, Borrós S, Fornaguera C. Efficient extracellular vesicles freeze-dry method for direct formulations preparation and use. Colloids Surf B Biointerfaces 2022; 218:112745. [PMID: 35930983 DOI: 10.1016/j.colsurfb.2022.112745] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 07/21/2022] [Accepted: 07/31/2022] [Indexed: 11/18/2022]
Abstract
Despite the great knowledge achieved in the field of extracellular vesicles (EVs), the short lifetime of EVs liquid formulation still hampers the transfer of EVs technology to clinical applications. In this context, freeze-dried EVs would be advantageous thanks to the enhanced stability of solid formulations. Although some previous attempts have already been reported, the efficiency of EVs lyophilization methodologies used remains insufficient, and the characterization of the resulting EVs is still incomplete. The current work aims to describe an alternative and easy-to-be-applied methodology for EVs lyophilization. The use of sucrose as lyoprotectant at 8.5%wt improved the cryopreservation efficiency. After the subsequent cycles of freeze-drying, properties such as size, morphology, purity, EVs specific markers, biocompatibility and the maintenance of their functionality were confirmed in freeze-dried EVs samples. To sum up, we have designed a methodology for the lyophilization of extracellular vesicles that enables the preservation of the physicochemical properties and functionality of EVs.
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Affiliation(s)
- Mònica Guarro
- Grup d'Enginyeria de Materials (Gemat), Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Via Augusta 390, 08017 Barcelona, Spain
| | - Francisca Suñer
- Grup d'Enginyeria de Materials (Gemat), Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Via Augusta 390, 08017 Barcelona, Spain
| | - Martí Lecina
- Grup d'Enginyeria de Materials (Gemat), Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Via Augusta 390, 08017 Barcelona, Spain
| | - Salvador Borrós
- Grup d'Enginyeria de Materials (Gemat), Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Via Augusta 390, 08017 Barcelona, Spain
| | - Cristina Fornaguera
- Grup d'Enginyeria de Materials (Gemat), Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Via Augusta 390, 08017 Barcelona, Spain.
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4
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Trenkenschuh E, Friess W. Freeze-drying of nanoparticles: How to overcome colloidal instability by formulation and process optimization. Eur J Pharm Biopharm 2021; 165:345-360. [PMID: 34052428 DOI: 10.1016/j.ejpb.2021.05.024] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/03/2021] [Accepted: 05/23/2021] [Indexed: 11/29/2022]
Abstract
Lyophilization of nanoparticle (NP) suspensions is a promising technology to improve stability, especially during long-term storage, and offers new routes of administration in solid state. Although considered as a gentle drying process, freeze-drying is also known to cause several stresses leading to physical instability, e.g. aggregation, fusion, or content leakage. NPs are heterogeneous regarding their physico-chemical properties which renders them different in their sensitivity to lyophilization stress and upon storage. But still basic concepts can be deducted. We summarize basic colloidal stabilization mechanisms of NPs in the liquid and the dried state. Furthermore, we give information about stresses occurring during the freezing and the drying step of lyophilization. Subsequently, we review the most commonly investigated NP types including lipophilic, polymeric, or vesicular NPs regarding their particle properties, stabilization mechanisms in the liquid state, and important freeze-drying process, formulation and storage strategies. Finally, practical advice is provided to facilitate purposeful formulation and process development to achieve NP lyophilizates with high colloidal stability.
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Affiliation(s)
- Eduard Trenkenschuh
- Pharmaceutical Technology and Biopharmaceutics, Department of Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, 81377 Munich, Germany
| | - Wolfgang Friess
- Pharmaceutical Technology and Biopharmaceutics, Department of Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, 81377 Munich, Germany.
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Sydykov B, Oldenhof H, Sieme H, Wolkers WF. Storage stability of liposomes stored at elevated subzero temperatures in DMSO/sucrose mixtures. PLoS One 2018; 13:e0199867. [PMID: 29975741 PMCID: PMC6033440 DOI: 10.1371/journal.pone.0199867] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/14/2018] [Indexed: 11/18/2022] Open
Abstract
Cryopreservation of biological materials is predominantly done using liquid nitrogen, and its application involves high maintenance costs and the need for periodical refilling of liquid nitrogen. Stable storage in mechanical freezers at −80°C would eliminate these issues and allow for shipment of frozen specimens using dry ice. In this work, the possibility of increasing the storage temperature of cryopreserved samples to −80°C by using combinations of DMSO and sucrose has been studied. Preservation efficacy was studied by measuring stability of liposomes encapsulated with carboxyfluorescein during storage at −150, −80 and −25°C for up to three months. Thermal and molecular mobility properties of the different DMSO-sucrose formulations were measured using differential scanning calorimetry, whereas hydrogen bonding interactions of the formulations were probed by Fourier transform infrared spectroscopy. It was found that addition of sucrose to DMSO solutions increases the Tg, and decreases molecular mobility in the glassy state at a particular temperature. Although it was expected that storage above or close to Tg at −80°C would affect liposome stability, stability was found to be similar compared to that of samples stored at −150°C. Higher molecular mobility in the glassy state could not be associated with faster CF-leakage rates. Distinct differences in storage stability at −25°C, far above Tg, were found among the sucrose/DMSO formulations, which were explained by the differences in permeability of sucrose and DMSO resulting in different levels of osmotic stress in the formulations.
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Affiliation(s)
- Bulat Sydykov
- Institute of Multiphase Processes, Leibniz Universität Hannover, Hannover, Germany
| | - Harriëtte Oldenhof
- Unit for Reproductive Medicine, Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Harald Sieme
- Unit for Reproductive Medicine, Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Willem F. Wolkers
- Institute of Multiphase Processes, Leibniz Universität Hannover, Hannover, Germany
- * E-mail:
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Sato YT, Umezaki K, Sawada S, Mukai SA, Sasaki Y, Harada N, Shiku H, Akiyoshi K. Engineering hybrid exosomes by membrane fusion with liposomes. Sci Rep 2016; 6:21933. [PMID: 26911358 PMCID: PMC4766490 DOI: 10.1038/srep21933] [Citation(s) in RCA: 398] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 02/03/2016] [Indexed: 12/18/2022] Open
Abstract
Exosomes are a valuable biomaterial for the development of novel nanocarriers as functionally advanced drug delivery systems. To control and modify the performance of exosomal nanocarriers, we developed hybrid exosomes by fusing their membranes with liposomes using the freeze–thaw method. Exosomes embedded with a specific membrane protein isolated from genetically modified cells were fused with various liposomes, confirming that membrane engineering methods can be combined with genetic modification techniques. Cellular uptake studies performed using the hybrid exosomes revealed that the interactions between the developed exosomes and cells could be modified by changing the lipid composition or the properties of the exogenous lipids. These results suggest that the membrane-engineering approach reported here offers a new strategy for developing rationally designed exosomes as hybrid nanocarriers for use in advanced drug delivery systems.
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Affiliation(s)
- Yuko T Sato
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kaori Umezaki
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Shinichi Sawada
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Sada-atsu Mukai
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yoshihiro Sasaki
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Naozumi Harada
- Department of Immuno-Gene Therapy, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan
| | - Hiroshi Shiku
- Department of Immuno-Gene Therapy, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan
| | - Kazunari Akiyoshi
- JST-ERATO, Akiyoshi Bio-nanotransporter Project, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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7
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Costa AP, Xu X, Burgess DJ. Freeze-Anneal-Thaw Cycling of Unilamellar Liposomes: Effect on Encapsulation Efficiency. Pharm Res 2013; 31:97-103. [DOI: 10.1007/s11095-013-1135-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/24/2013] [Indexed: 11/29/2022]
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8
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Izutsu KI, Yomota C, Kawanishi T. Stabilization of Liposomes in Frozen Solutions Through Control of Osmotic Flow and Internal Solution Freezing by Trehalose. J Pharm Sci 2011; 100:2935-44. [DOI: 10.1002/jps.22518] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/07/2010] [Accepted: 01/25/2011] [Indexed: 11/05/2022]
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9
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Ducat E, Brion M, Lecomte F, Evrard B, Piel G. The experimental design as practical approach to develop and optimize a formulation of peptide-loaded liposomes. AAPS PharmSciTech 2010; 11:966-75. [PMID: 20512433 DOI: 10.1208/s12249-010-9463-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 05/13/2010] [Indexed: 01/25/2023] Open
Abstract
To investigate the encapsulation of Print 3G, a peptidic agent that could reduce the angiogenic development of breast tumors, pegylated liposomes used as intravenous vectors were studied and characterized. Recently, the path of liposomes has been explored with success to improve the pharmacological properties of peptidic drugs and to stabilize them. In this study, loaded unilamellar vesicles composed of SPC:CHOL:mPEG2000-DSPE (47:47:6) were prepared by the hydration of lipid film technique. An HPLC method was developed and validated for the determination of Print 3G to calculate its encapsulation efficiency. Observed Print 3G adsorption on different materials employed during liposome preparation (such as glass beads, tubing, and connections for extrusion) led to the modification of the manufacturing method. The freeze-thawing technique was used to enhance the amount of Print 3G encapsulated into blank liposomes prepared using the hydration of lipid film procedure. Many factors may influence peptide entrapment, namely the number of freeze-thawing cycles, the lipid concentration, the peptide concentration, and the mixing time. Consequently, a design of experiments was performed to obtain the best encapsulation efficiency while minimizing the number of experiments. The lipid concentration and the number of freeze-thawing cycles were identified as the positive factors influencing the encapsulation. As a result of the optimization, an optimum was found and encapsulation efficiencies were improved from around 30% to 63%. Liposome integrity was evaluated by photon correlation spectroscopy and freeze-fracture electron microscopy to ensure that the selected formulation possesses the required properties to be a potential candidate for further in vitro and in vivo experiments.
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10
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Cabane B, Blanchon S, Neves C. Recombination of nanometric vesicles during freeze-drying. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:1982-90. [PMID: 16489779 DOI: 10.1021/la051923g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Concentrated dispersions of nanometric lipid vesicles (mean diameter 20 nm) in water/maltose solutions have been freeze-dried and then redispersed in water, yielding again dispersions of lipid vesicles. At each stage of the freeze-drying process, the organization of the vesicles in the dispersion and their size distribution were examined through small-angle neutron scattering and gel permeation chromatography. It was found that the osmotic deswelling of the vesicles caused them to recombine into larger vesicles. A single burst of recombination events occurred when the maltose concentration in the aqueous phase rose above 100 g/L. The final vesicle population was monopopulated, with a central diameter about twice as large as that of the original dispersion.
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Affiliation(s)
- B Cabane
- PMMH, ESPCI, 10 rue Vauquelin, 75231 Paris Cedex 05, France
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11
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Phospholipid-stabilized nanoparticles of cyclosporine a by rapid expansion from supercritical to aqueous solution. AAPS PharmSciTech 2004. [DOI: 10.1007/bf02830579] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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12
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Young TJ, Johnston KP, Pace GW, Mishra AK. Phospholipid-stabilized nanoparticles of cyclosporine A by rapid expansion from supercritical to aqueous solution. AAPS PharmSciTech 2004; 5:E11. [PMID: 15198532 PMCID: PMC2784862 DOI: 10.1208/pt050111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The purpose of this research was to form stable suspensions of submicron particles of cyclosporine A, a water-insoluble drug, by rapid expansion from supercritical to aqueous solution (RESAS). A solution of cyclosporine A in CO2 was expanded into an aqueous solution containing phospholipid vesicles mixed with nonionic surfactants to provide stabilization against particle growth resulting from collisions in the expanding jet. The products were evaluated by measuring drug loading with high performance liquid chromatography (HPLC), particle sizing by dynamic light scattering (DLS), and particle morphology by transmission electron microscopy (TEM) and x-ray diffraction. The ability of the surfactant molecules to orient at the surface of the particles and provide steric stabilization could be manipulated by changing process variables including temperature and suspension concentration. Suspensions with high payloads (up to 54 mg/mL) could be achieved with a mean diameter of 500 nm and particle size distribution ranging from 40 to 920 nm. This size range is several hundred nanometers smaller than that produced by RESAS for particles stabilized by Tween 80 alone. The high drug payloads (approximately 10 times greater than the equilibrium solubility), the small particle sizes, and the long-term stability make this process attractive for development.
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Affiliation(s)
- Timothy J. Young
- />Department of Chemical Engineering, University of Texas, 78712-1062 Austin, TX
| | - Keith P. Johnston
- />Department of Chemical Engineering, University of Texas, 78712-1062 Austin, TX
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13
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Zhang W, van Winden EC, Bouwstra JA, Crommelin DJ. Enhanced permeability of freeze-dried liposomal bilayers upon rehydration. Cryobiology 1997; 35:277-89. [PMID: 9367615 DOI: 10.1006/cryo.1997.2050] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Until now, studies on the protection of liposomes against freeze-drying damage have mainly focused on the bilayer integrity during the freezing or drying step of this process. Here, we investigated the bilayer permeability of freeze-dried, lyoprotected liposomes to a nonbilayer interacting compound after rehydration, by monitoring the leak-in kinetics of externally added carboxyfluorescein (CF). The results showed that freeze-drying and rehydration of DPPC:DPPG 10:1 liposomes with sucrose in- and outside the vesicles caused a temporary increase in the bilayer permeability for CF, which leveled off after approximately 20 h. The amount of CF/mol phospholipid which leaked into the vesicles increased with vesicle size (range 0.1-1 micro m) / lamellarity. Reduction of the number of bilayers in 1-1 micro m) vesicles enhanced the permeability to CF after freeze-drying and rehydration. The presence of CHOL decreased CF leak-in rates into 1 micro m MLVs consisting of DPPC:DPPG 10:1, but not into 0.1-micro m unilamellar vesicles. In the absence of sucrose similar leak-in profiles as a function of time were found after rehydration, suggesting that repacking processes of the bilayer were responsible for the enhanced permeability after freeze-drying and dehydration both with and without sucrose. The effect of size and lamellarity on the CF leak-in correlated with the retention of encapsulated CF after freeze-drying and rehydration, but no correlation was found with the effect of lipid composition. Both small (0.1 micro m) lyoprotected liposomes made of DPPC:DPPG 10:1 and DPPC:DPPG:CHOL 10:1:4 were highly permeable during the rehydration step itself. The results indicate that, despite the presence of the lyoprotectant, "repacking" of the bilayer components takes place both during and after rehydration. This eventually leads to regaining of its barrier function.
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Affiliation(s)
- W Zhang
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3508 TB, The Netherlands
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14
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de Chasteigner S, Cav� G, Fessi H, Devissaguet JP, Puisieux F. Freeze-drying of itraconazole-loaded nanosphere suspensions: a feasibility study. Drug Dev Res 1996. [DOI: 10.1002/(sici)1098-2299(199606)38:2<116::aid-ddr6>3.0.co;2-m] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Long-term stability of liposomes containing both tissue-type plasminogen activator and glu-plasminogen. Int J Pharm 1996. [DOI: 10.1016/0378-5173(95)04325-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Kristiansen J. Leakage of a trapped fluorescent marker from liposomes: effects of eutectic crystallization of NaCl and internal freezing. Cryobiology 1992; 29:575-84. [PMID: 1424714 DOI: 10.1016/0011-2240(92)90062-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Leakage of trapped carboxyfluorescein from DL-alpha-dipalmitoylphosphatidylcholine multilamellar liposomes (diameter 1-2 microns) in NaCl solutions was measured after rapid freezing to temperatures between -15 and -55 degrees C. Leakage was low after freezing between -15 and -35 degrees C, but increased steeply between -35 and -45 degrees C. From DSC measurements it was found that the increase in leakage was associated with two crystallization processes: Eutectic crystallization of NaCl and freezing of undercooled solvent trapped in the interior of the liposomes ("internal freezing"). Damage caused by the former process could effectively be prevented by small amounts of trehalose (1% less than or equal to w less than or equal to 1.5%). Trehalose in these concentration also decreased damage due to internal freezing, but to a minor degree. In addition to these damaging transitions, a time-dependent process was found to cause leakage from the liposomes at -25 degrees C. The association between leakage and thermal activity suggests that DSC supplements cryomicroscopy and leakage measurements in the characterization of cryostability of liposomes.
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Affiliation(s)
- J Kristiansen
- Department of Chemistry, H.C. Orsted Institute, University of Copenhagen, Denmark
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