A Commemorative Issue in Honor of Professor Gregory Gregoriadis: Liposomes for the Delivery of Drugs and Vaccines

A special issue of Pharmaceutics (ISSN 1999-4923). This special issue belongs to the section "Physical Pharmacy and Formulation".

Deadline for manuscript submissions: 30 June 2024 | Viewed by 16642

Special Issue Editor

1. Laboratory of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, University of Patras, 26504 Rio-Patras, Greece
2. Institute for Chemical Engineering Sciences, Foundation for Research and Technology Hellas, FORTH/ICE-HT, Stadiou Street, 26510 Platani-Rio, Greece
Interests: targeted drug delivery; nanomedicines; liposome technology; lipid-based formulations
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Special Issue Information

The therapeutic potential of certain categories of drugs, such as drugs with high molecular weight, low aqueous solubility, and/or high permeability, narrow therapeutic range and also drugs that are liable in blood and/or at the site of administration/absorption, cannot be manifested unless particular delivery challenges are overcome. The design and development of liposomal drugs may offer solutions to such delivery problems, especially if the liposomal carriers can reach, and deliver the associated drug to their specific biological targets. In addition to Drug Delivery solutions, liposomes can offer solutions to vaccination limitations. Vaccination is often hampered by the presence of infectious agents, weak immune responses and prohibiting costs, especially in the developing world. Such problems may be circumvented by immunisation with nucleic acids (eg. plasmid DNA, siRNA, mRNA), especially when associated with cationic lipids in the form of liposomes and other lipid-based nanoparticles, as exemplified by the current efforts for the prevention of Covid 19 virus pandemic. The contributors of the present volume deal with the background and progress made so far with liposomes for drug delivery and targeting, as well as vaccines, (especially nucleic acid vaccines). Theoretical and practical advantages as well as potential risks are discussed.

Keywords

  • liposomes for drug delivery (for therapy of cancer, infectious diseases, neurodegenerative diseases, etc.)
  • development, applications, and challenges of ligand-targeted liposomal drugs
  • liposomes and biological barriers
  • liposomes as immunological adjuvants
  • cationic liposomes and lipid nanoparticles as vaccine carriers
  • immunization with nucleic acids in liposomes
  • entrapment of nucleic acid vaccines in cationic liposomes

Published Papers (7 papers)

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Research

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13 pages, 3704 KiB  
Article
QS21-Initiated Fusion of Liposomal Small Unilamellar Vesicles to Form ALFQ Results in Concentration of Most of the Monophosphoryl Lipid A, QS21, and Cholesterol in Giant Unilamellar Vesicles
by Erwin G. Abucayon, Mangala Rao, Gary R. Matyas and Carl R. Alving
Pharmaceutics 2023, 15(9), 2212; https://doi.org/10.3390/pharmaceutics15092212 - 26 Aug 2023
Viewed by 919
Abstract
Army Liposome Formulation with QS21 (ALFQ), a vaccine adjuvant preparation, comprises liposomes containing saturated phospholipids, with 55 mol% cholesterol relative to the phospholipids, and two adjuvants, monophosphoryl lipid A (MPLA) and QS21 saponin. A unique feature of ALFQ is the formation of giant [...] Read more.
Army Liposome Formulation with QS21 (ALFQ), a vaccine adjuvant preparation, comprises liposomes containing saturated phospholipids, with 55 mol% cholesterol relative to the phospholipids, and two adjuvants, monophosphoryl lipid A (MPLA) and QS21 saponin. A unique feature of ALFQ is the formation of giant unilamellar vesicles (GUVs) having diameters >1.0 µm, due to a remarkable fusion event initiated during the addition of QS21 to nanoliposomes containing MPLA and 55 mol% cholesterol relative to the total phospholipids. This results in a polydisperse size distribution of ALFQ particles, with diameters ranging from ~50 nm to ~30,000 nm. The purpose of this work was to gain insights into the unique fusion reaction of nanovesicles leading to GUVs induced by QS21. This fusion reaction was probed by comparing the lipid compositions and structures of vesicles purified from ALFQ, which were >1 µm (i.e., GUVs) and the smaller vesicles with diameter <1 µm. Here, we demonstrate that after differential centrifugation, cholesterol, MPLA, and QS21 in the liposomal phospholipid bilayers were present mainly in GUVs (in the pellet). Presumably, this occurred by rapid lateral diffusion during the transition from nanosize to microsize particles. While liposomal phospholipid recoveries by weight in the pellet and supernatant were 44% and 36%, respectively, higher percentages by weight of the cholesterol (~88%), MPLA (94%), and QS21 (96%) were recovered in the pellet containing GUVs, and ≤10% of these individual liposomal constituents were recovered in the supernatant. Despite the polydispersity of ALFQ, most of the cholesterol, and almost all of the adjuvant molecules, were present in the GUVs. We hypothesize that the binding of QS21 to cholesterol caused new structural nanodomains, and subsequent interleaflet coupling in the lipid bilayer might have initiated the fusion process, leading to creation of GUVs. However, the polar regions of MPLA and QS21 together have a “sugar lawn” of ten sugars, the hydrophilicity of which might have provided a driving force for rapid lateral diffusion and concentration of the MPLA and QS21 in the GUVs. Full article
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20 pages, 2255 KiB  
Article
Synthesis of Novel Arsonolipids and Development of Novel Arsonoliposome Types
by Spyridon Mourtas, Konstantina Papadia, Golfo G. Kordopati, Panayiotis V. Ioannou, Sophia G. Antimisiaris and Gerasimos M. Tsivgoulis
Pharmaceutics 2022, 14(8), 1649; https://doi.org/10.3390/pharmaceutics14081649 - 08 Aug 2022
Cited by 1 | Viewed by 1440
Abstract
Arsonolipids represent a class of arsenic-containing compounds with interesting biological properties either as monomers or as nanostructure forming components, such as arsonoliposomes that possess selective anticancer activity as proven by in vitro and in vivo studies. In this work, we describe, for the [...] Read more.
Arsonolipids represent a class of arsenic-containing compounds with interesting biological properties either as monomers or as nanostructure forming components, such as arsonoliposomes that possess selective anticancer activity as proven by in vitro and in vivo studies. In this work, we describe, for the first time, the synthesis of novel arsono-containing lipids where the alkyl groups are connected through stable ether bonds. It is expected that this class of arsonolipids, compared with the corresponding ester linked, will have higher chemical stability. To accomplish this task, a new methodology of general application was developed, where a small arsono compound, 2-hydroxyethylarsonic acid, when protected with thiophenol, can be used in an efficient and simple way as a building block for the synthesis of arsono-containing lipids as well as other arsono-containing biomolecules. Thus, besides the above-mentioned arsonolipid, an arsono cholesterol derivative was also obtained. Both ether arsonolipid and arsono cholesterol were able to form liposomes having similar physicochemical properties and integrity to conventional arsonoliposomes. Furthermore, a preliminary in vitro anticancer potential assessment of the novel ether arsonolipid containing liposomes against human prostate cancer (PC-3) and Lewis lung carcinoma (LLC) cells showed significant activity (dose- and time-dependent), which was similar to that of the conventional arsonoliposomes (studied before). Given the fact that novel arsonolipids may be more stable compared to the ones used in conventional arsonoliposomes, the current results justify further exploitation of the novel compounds by in vitro and in vivo studies. Full article
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20 pages, 4483 KiB  
Article
“Endothelial Antibody Factory” at the Blood Brain Barrier: Novel Approach to Therapy of Neurodegenerative Diseases
by Reynald Thinard, Attila E. Farkas, Marta Halasa, Melanie Chevalier, Klaudia Brodaczewska, Aleksandra Majewska, Robert Zdanowski, Maria Paprocka, Joanna Rossowska, Lam Tri Duc, Ruth Greferath, Istvan Krizbai, Fred Van Leuven, Claudine Kieda and Claude Nicolau
Pharmaceutics 2022, 14(7), 1418; https://doi.org/10.3390/pharmaceutics14071418 - 06 Jul 2022
Cited by 2 | Viewed by 2516
Abstract
The failures of anti-β-amyloid immunotherapies suggested that the very low fraction of injected antibodies reaching the brain parenchyma due to the filtering effect of the BBB may be a reason for the lack of therapeutic effect. However, there is no treatment, as yet, [...] Read more.
The failures of anti-β-amyloid immunotherapies suggested that the very low fraction of injected antibodies reaching the brain parenchyma due to the filtering effect of the BBB may be a reason for the lack of therapeutic effect. However, there is no treatment, as yet, for the amyotrophic lateral sclerosis (ALS) despite substantial evidence existing of the involvement of TDP-43 protein in the evolution of ALS. To circumvent this filtering effect, we have developed a novel approach to facilitate the penetration of antibody fragments (Fabs) into the brain parenchyma. Leveraging the homing properties of endothelial progenitor cells (EPCs), we transfected, ex vivo, such cells with vectors encoding anti-β-amyloid and anti-TDP43 Fabs turning them into an “antibody fragment factory”. When injected these cells integrate into the BBB, where they secrete anti-TDP43 Fabs. The results showed the formation of tight junctions between the injected engineered EPCs and the unlabeled resident endothelial cells. When the EPCs were further modified to express the anti-TDP43 Fab, we could observe integration of these cells into the vasculature and the secretion of Fabs. Results confirm that production and secretion of Fabs at the BBB level leads to their migration to the brain parenchyma where they might exert a therapeutic effect. Full article
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13 pages, 1909 KiB  
Article
The pH-Responsive Liposomes—The Effect of PEGylation on Release Kinetics and Cellular Uptake in Glioblastoma Cells
by Eirik A. L. Rustad, Susannah von Hofsten, Robin Kumar, Eirik A. Lænsman, Gerd Berge and Nataša Škalko-Basnet
Pharmaceutics 2022, 14(6), 1125; https://doi.org/10.3390/pharmaceutics14061125 - 25 May 2022
Cited by 3 | Viewed by 2334
Abstract
Nanomedicine has been, to a certain degree, a success story in the development of superior anticancer therapies. However, there are tumors that remain a huge challenge for nanoformulations, for instance, brain tumors such as glioblastoma, the most common and aggressive brain tumor. To [...] Read more.
Nanomedicine has been, to a certain degree, a success story in the development of superior anticancer therapies. However, there are tumors that remain a huge challenge for nanoformulations, for instance, brain tumors such as glioblastoma, the most common and aggressive brain tumor. To utilize the fact that such tumors are characterized by an acidic extracellular environment, we selected pH-responsive liposomes as a potential drug delivery system for superior delivery to GBM. Liposomes comprising PEGylated lipid of two chain lengths with encapsulated fluorescent marker calcein were characterized and challenged against non-PEGylated vesicles. The in vitro calcein release from three liposomal formulations (<200 nm), namely non-PEGylated (pH-Lip) and PEGylated, pH-Lip–PEG750, and pH-Lip–PEG2000, was followed at three pH conditions to prove the pH-responsiveness. The intracellular delivery of a liposomally encapsulated marker was determined in GL261 glioblastoma cell lines in vitro using both flow cytometry and confocal microscopy. The inclusion of PEG2000 within liposomal formulation resulted in reduced in vitro pH-responsiveness compared to pH-Lip and pH-Lip750. All three pH-responsive liposomal formulations improved intracellular uptake in GL261 cells compared to non-pH-responsive liposomes, with negligible differences regarding PEG length. The proposed formulations should be further evaluated in glioblastoma models. Full article
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30 pages, 6490 KiB  
Article
Inclusion of a Phytomedicinal Flavonoid in Biocompatible Surface-Modified Chylomicron Mimic Nanovesicles with Improved Oral Bioavailability and Virucidal Activity: Molecular Modeling and Pharmacodynamic Studies
by Mohamed Y. Zakaria, Paris E. Georghiou, Joseph H. Banoub and Botros Y. Beshay
Pharmaceutics 2022, 14(5), 905; https://doi.org/10.3390/pharmaceutics14050905 - 21 Apr 2022
Cited by 17 | Viewed by 2044
Abstract
Morin hydrate (MH) is a widely-used Asian phytomedicinal flavonoid with a wide range of reported therapeutic activities. However, MH has limited oral bioavailability due to its low aqueous solubility and intestinal permeability, which in turn hinders its potential antiviral activity. The study reported [...] Read more.
Morin hydrate (MH) is a widely-used Asian phytomedicinal flavonoid with a wide range of reported therapeutic activities. However, MH has limited oral bioavailability due to its low aqueous solubility and intestinal permeability, which in turn hinders its potential antiviral activity. The study reported herein was designed to encapsulate MH in polyethyleneglycolated (PEGylated) chylomicrons (PCMs) and to boost its antiviral activity and biological availability for oral administration using a rat experimental model. The PEGylated edge activator combined with the conventional components of chylomicrons (CMs) amplify the transport of the drug across the intestine and its circulation period, hence its therapeutic impact. The implementation of variables in the in vitro characterization of the vesicles was investigated. Using Design Expert® software, a 24 factorial design was conducted, and the resulting PCM formulations were fabricated utilizing a thin-film hydration technique. The efficacy of the formulations was assessed according to their zeta potential (ZP), entrapment efficiency percentage (EE%), amount of drug released after 8 h (Q8h), and particle size (PS) data. Formulation F9, which was deemed to be the optimal formula, used compritol as the lipidic core together in defined amounts with phosphatidylcholine (PC) and Brij52. Computer-aided studies revealed that MH alone in a suspension had both diminished intestinal permeability and absorption, but was enhanced when loaded in PCMs. This was affirmed by the superiority of formulation F9 results in ex vivo permeation and pharmacokinetic studies. Furthermore, formulation F9 had a superior safety profile and antiviral activity over a pure MH suspension. Molecular-docking studies revealed the capability of MH to inhibit MERS-CoV 3CLpro, the enzyme shown to exhibit a crucial role in viral replication. Additionally, F9 suppressed both MERS-CoV-induced histopathological alteration in lung tissue and resulting oxidative and inflammatory biomarkers. Collectively, the results reported herein affirmed the potential of PCMs as nanocarriers for the effective oral administration of MH as an antiviral. Full article
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21 pages, 2903 KiB  
Article
Moxifloxacin Liposomes: Effect of Liposome Preparation Method on Physicochemical Properties and Antimicrobial Activity against Staphylococcus epidermidis
by Evangelos Natsaridis, Foteini Gkartziou, Spyridon Mourtas, Marc C. A. Stuart, Fevronia Kolonitsiou, Pavlos Klepetsanis, Iris Spiliopoulou and Sophia G. Antimisiaris
Pharmaceutics 2022, 14(2), 370; https://doi.org/10.3390/pharmaceutics14020370 - 07 Feb 2022
Cited by 7 | Viewed by 2672
Abstract
The aim of this study was the development of optimal sustained-release moxifloxacin (MOX)-loaded liposomes as intraocular therapeutics of endophthalmitis. Two methods were compared for the preparation of MOX liposomes; the dehydration–rehydration (DRV) method and the active loading method (AL). Numerous lipid-membrane compositions were [...] Read more.
The aim of this study was the development of optimal sustained-release moxifloxacin (MOX)-loaded liposomes as intraocular therapeutics of endophthalmitis. Two methods were compared for the preparation of MOX liposomes; the dehydration–rehydration (DRV) method and the active loading method (AL). Numerous lipid-membrane compositions were studied to determine the potential effect on MOX loading and retention in liposomes. MOX and phospholipid contents were measured by HPLC and a colorimetric assay for phospholipids, respectively. Vesicle size distribution and surface charge were measured by DLS, and morphology was evaluated by cryo-TEM. The AL method conferred liposomes with higher MOX encapsulation compared to the DRV method for all the lipid compositions used. Cryo-TEM showed that both liposome types had round vesicular structure and size around 100–150 nm, while a granular texture was evident in the entrapped aqueous compartments of most AL liposomes, but substantially less in DRV liposomes; X-ray diffraction analysis demonstrated slight crystallinity in AL liposomes, especially the ones with highest MOX encapsulation. AL liposomes retained MOX for significantly longer time periods compared to DRVs. Lipid composition did not affect MOX release from DRV liposomes but significantly altered drug loading/release in AL liposomes. Interestingly, AL liposomes demonstrated substantially higher antimicrobial potential towards S. epidermidis growth and biofilm susceptibility compared to corresponding DRV liposomes, indicating the importance of MOX retention in liposomes on their activity. In conclusion, the liposome preparation method/type determines the rate of MOX release from liposomes and modulates their antimicrobial potential, a finding that deserves further in vitro and in vivo exploitation. Full article
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16 pages, 699 KiB  
Review
Liposomes as Tools to Improve Therapeutic Enzyme Performance
by Maria Eugénia Meirinhos Cruz, Maria Luísa Corvo, Maria Bárbara Martins, Sandra Simões and Maria Manuela Gaspar
Pharmaceutics 2022, 14(3), 531; https://doi.org/10.3390/pharmaceutics14030531 - 27 Feb 2022
Cited by 9 | Viewed by 2968
Abstract
The drugs concept has changed during the last few decades, meaning the acceptance of not only low molecular weight entities but also macromolecules as bioagent constituents of pharmaceutics. This has opened a new era for a different class of molecules, namely proteins in [...] Read more.
The drugs concept has changed during the last few decades, meaning the acceptance of not only low molecular weight entities but also macromolecules as bioagent constituents of pharmaceutics. This has opened a new era for a different class of molecules, namely proteins in general and enzymes in particular. The use of enzymes as therapeutics has posed new challenges in terms of delivery and the need for appropriate carrier systems. In this review, we will focus on enzymes with therapeutic properties and their applications, listing some that reached the pharmaceutical market. Problems associated with their clinical use and nanotechnological strategies to solve some of their drawbacks (i.e., immunogenic reactions and low circulation time) will be addressed. Drug delivery systems will be discussed, with special attention being paid to liposomes, the most well-studied and suitable nanosystem for enzyme delivery in vivo. Examples of liposomal enzymatic formulations under development will be described and successful pre-clinical results of two enzymes, L-Asparaginase and Superoxide dismutase, following their association with liposomes will be extensively discussed. Full article
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