In the context of increased interest in permeability enhancement technologies to achieve mucosal delivery of drugs and biologics, we report our study on effects of the amphiphilic surfactant at cell membrane and cell population levels. Our results show that modulation in membrane order and fluidity initially occurs on insertion of individual surfactant molecules into the outer leaflet of membrane lipid bilayer; a process occurring at concentrations below surfactant's critical micellar concentration. The surfactant insertion, and consequent increase in membrane fluidity, are observed to be spatially heterogenous, i.
View Article and Find Full Text PDFThe temporary silencing of disease-associated genes utilising short interfering RNA (siRNA) is a potent and selective route for addressing a wide range of life limiting disorders. However, the few clinically approved siRNA therapies rely on lipid based formulations, which although potent, provide limited chemical space to tune the stability, efficacy and tissue selectivity. In this study, we investigated the role of molar mass and histidinylation for poly(lysine) based non-viral vectors, synthesised through a fully aqueous thermal condensation polymerisation.
View Article and Find Full Text PDFThis study investigated the application of a temperature-responsive methylcellulose-hyaluronic acid (MC-HA) hydrogel to support 3D cell growth . Initial work focused on the preparation of hydrogels for 3D culture, followed by investigations of the biological compatibility of hydrogel components and optimization of the cell culture environment. Evaluation of viability and proliferation of HCT116 cells cultured in the MC-HA hydrogel was used to adjust the blend composition to design a hydrogel with optimal properties to support cell growth.
View Article and Find Full Text PDFMucus is the first biological component inhaled drugs encounter on their journey towards their pharmacological target in the upper airways. Yet, how mucus may influence drug disposition and efficacy in the lungs has been essentially overlooked. In this study, a simple in vitro system was developed to investigate the factors promoting drug interactions with airway mucus in physiologically relevant conditions.
View Article and Find Full Text PDFAlthough the mucus layer is the first biological barrier encountered by inhaled drugs upon their deposition in the upper airways, its potential impact on drug dissolution and absorption in the lung has hardly been investigated. Bio-relevant in vitro models were therefore used to assess the role of airway mucus in the fate of drug particles at the air-epithelium interface. Salbutamol and indomethacin were used as model Biopharmaceutics Classification System (BCS) class III and class II drugs, respectively.
View Article and Find Full Text PDFCationic polymers have emerged as a promising alternative to viral vectors in gene therapy. They are cheap to scale up, easy to functionalise and are potentially safer than viral vectors, however many are cytotoxic. The large number of polycations, designed to address the toxicity problem, raises a practical need to develop a fast and reliable method for assessing the safety of these materials.
View Article and Find Full Text PDFHere we describe a rapid inkjet formulation method for screening newly-synthesised cationic materials for siRNA delivery into cancer cells. Reduction responsive oligo-β-aminoesters were prepared and evaluated for their ability to condense siRNA into polyplexes through a fast inkjet printing method. A direct relationship between the oligomer structures and charge densities, and the final cell response in terms of uptake rate and transfection efficacy, was found.
View Article and Find Full Text PDFExpert Opin Drug Deliv
August 2018
Introduction: Research into oral delivery of biologics has a long and rich history but has not produced technologies used in the clinic. The area has evolved in terms of strategies to promote oral biologics delivery from early chemical absorption enhancers to nanomedicine to devices. Continued activity in this area is justifiable considering the remarkable proliferation of biologics.
View Article and Find Full Text PDFPermeability enhancers are receiving increased attention arising from their ability to increase transepithelial permeability and thus, bioavailability of orally or pulmonary administered biopharmaceutics. Here we present the synthesis and the in vitro assaying of a series of lactose-based non-ionic surfactants, highlighting the relationship between their structure and biological effect. Using tensiometric measurements the critical micelle concentrations (CMCs) of the surfactants were determined and demonstrate that increasing hydrophobic chain length reduces surfactant CMC.
View Article and Find Full Text PDFIn the treatment of lung cancer, there is an urgent need of innovative medicines to optimize pharmacological responses of conventional chemotherapeutics while attenuating side effects. Here, we have exploited some relatively unexplored subtle differences in reduction potential, associated with cancer cell microenvironments in addition to the well-known changes in intracellular redox environment. We report the synthesis and application of novel redox-responsive PLGA (poly(lactic-co-glycolic acid)) -PEG (polyethylene glycol) nanoparticles (RR-NPs) programmed to change surface properties when entering tumor microenvironments, thus enhancing cell internalization of the particles and their drug cargo.
View Article and Find Full Text PDFDespite research efforts full potential of siRNA-based therapeutics has not yet been fully realized due to a need for suitable, effective delivery formulations. Here, we examine a potential of a new class of water-soluble chitosans as siRNA platform for pulmonary delivery. The system is based on piperazine-substituted chitosans, a material designed to integrate established, safe application of chitosan for mucosal administration with novel properties: the piperazine-substituted chitosans are freely water-soluble at physiological pH, possess low cytotoxicity (no significant reduction in cell viability up to 0.
View Article and Find Full Text PDFIn this work we utilize the combination of label-free total internal reflection microscopy and total internal reflectance fluorescence (TIRM/TIRF) microscopy to achieve a simultaneous, live imaging of single, label-free colloidal particle endocytosis by individual cells. The TIRM arm of the microscope enables label free imaging of the colloid and cell membrane features, while the TIRF arm images the dynamics of fluorescent-labeled clathrin (protein involved in endocytosis via clathrin pathway), expressed in transfected 3T3 fibroblasts cells. Using a model polymeric colloid and cells with a fluorescently tagged clathrin endocytosis pathway, we demonstrate that wide field TIRM/TIRF coimaging enables live visualization of the process of colloidal particle interaction with the labeled cell structure, which is valuable for discerning the membrane events and route of colloid internalization by the cell.
View Article and Find Full Text PDFThe ability to deliver therapeutically relevant amounts of drugs directly from the nasal cavity to the central nervous system to treat neurological diseases is dependent on the availability of efficient drug delivery systems. Increased delivery and/or therapeutic effect has been shown for drugs encapsulated in nanoparticles; however, the factors governing the transport of the drugs and/or the nanoparticles from the nasal cavity to the brain are not clear. The present study evaluates the potential transport of nanoparticles across the olfactory epithelium in relation to nanoparticle characteristics.
View Article and Find Full Text PDFThis study investigated the effect of nanoparticle size (50 and 100 nm) and surface charge on their interaction with Caco-2 monolayers as a model of the intestinal epithelium, including cell internalization pathways and the level of transepithelial transport. Initially, toxicity assays showed that cell viability and cell membrane integrity were dependent on the surface charge and applied mass, number, and total surface area of nanoparticles, as tested in two epithelial cell lines, colon carcinoma Caco-2 and airway Calu-3. This also identified suitable nanoparticle concentrations for subsequent cell uptake experiments.
View Article and Find Full Text PDFPurpose: CriticalSorb™, with the principal component Solutol® HS15, is a novel mucosal drug delivery system demonstrated to improve the bioavailability of selected biotherapeutics. The intention of this study is to elucidate mechanism(s) responsible for the enhancement of trans-mucosal absorption of biological drugs by Solutol® HS15.
Methods: Micelle size and CMC of Solutol® HS15 were determined in biologically relevant media.
This work examines the potential drug delivery barrier of the basement membrane (BM) by assessing the permeability of select macromolecules and nanoparticles. The study further extends to probing the effect of BM on intestinal epithelial cell attachment and monolayer characteristics, including cell morphology. Serum-free cultured Caco-2 cells were grown on BM-containing porous supports, which were obtained by prior culture of airway epithelial cells (Calu-3), shown to assemble and deposit a BM on the growth substrate, followed by decellularisation.
View Article and Find Full Text PDFThe production of microparticles using a supercritical carbon dioxide based PGSS technique (CriticalMix™) has been exploited to develop blended systems targeted at pulmonary delivery. Hence, PEG based polymers of different molecular weights (1000-6000 Da) were blended in situ with fatty acids (stearic, palmitic or myristic acid) or with commercially available PEG-stearates. The effect of the different thermodynamic properties of the polymers was evaluated by characterising the microparticles produced in terms of their melting temperature by conventional DSC and in the presence of high pressure CO(2) using a high pressure variable volume view cell.
View Article and Find Full Text PDFThe thermodynamic behaviour of selected polymeric components for preparation of controlled release microparticles using supercritical carbon dioxide (scCO(2)) processing was investigated. The polymeric materials selected were egg lecithin (a model for the lung surfactant phospholipid), poly(ethyleneglycol) (PEG) of different molecular weights, fatty acids (C18, C16, and C14), and physical blends of PEGs and fatty acids. In addition a range of PEG-stearates was also assessed.
View Article and Find Full Text PDFMany cell therapy approaches aim to deliver high-density single-cell suspensions to diseased or injured sites in the body. Long term clinical success will in part be dependent on the cells that remain viable and that assume correct functionality post-administration. The research presented in this paper focuses on the potential of cell aggregate delivery to generate a more supportive environment for cells than single cell suspensions.
View Article and Find Full Text PDFPurpose: Novel biodegradable and mucoadhesive PLGA/chitosan microparticles with the potential for use as a controlled release gastroretentive system were manufactured using supercritical CO(2) (scCO(2)) by the Particle Gas Saturated System (PGSS) technique (also called CriticalMix(TM)).
Methods: Microparticles were produced from PLGA with the addition of mPEG and chitosan in the absence of organic solvents, surfactants and crosslinkers using the PGSS technique. Microparticle formulations were morphologically characterized by scanning electron microscope; particle size distribution was measured using laser diffraction.
Interleukin-4-inducing principle from schistosome eggs (IPSE/alpha-1) is a protein produced exclusively by the eggs of the trematode Schistosoma mansoni. IPSE/alpha-1 is a secretory glycoprotein which activates human basophils via an IgE-dependent but non-antigen-specific mechanism. Sequence analyses revealed a potential nuclear localization signal (NLS) at the C terminus of IPSE/alpha-1.
View Article and Find Full Text PDFIt is known that two cytoskeleton components, microtubules and actins filaments, are required for efficient endocytosis. The relative importance of these two components in the cellular uptake of 2-(dimethylamino)ethyl methacrylate (DMAEMA)-DNA polyplexes was investigated in this study by applying microtubule depolymerising agent, colchicine, and actin polymerising inhibitor, cytochalasin D, in a cell transfection study. The effect of colchicine on transfection efficiency of polyplexes was found to be a time-dependent phenomenon, whereby the level of gene expression was inhibited at early stage, presumably to the disruption of a transport of vesicles along microtubules by colchicine.
View Article and Find Full Text PDFThis review aims to evaluate the evidence for the existence of a direct nose-to-brain delivery route for nanoparticles administered to the nasal cavity and transported via the olfactory epithelium and/or via the trigeminal nerves directly to the CNS. This is relevant in the field of drug delivery as well as for new developments in nanotechnology. Experiments in animal models have shown that nano-sized drug delivery systems can enhance nose-to-brain delivery of drugs compared to equivalent drug solutions formulations.
View Article and Find Full Text PDFSmall molecular weight drugs, peptides, and nanoparticles have previously been shown to localize in the central nervous system after intraneural administration. A basic understanding of direct nose-to-brain drug delivery, particularly for nanoparticles with different physicochemical characteristics, remains unclear. In this study, fluorescence microscopy and stereology were used to track intranasally administered chitosan-coated polystyrene (C-PS) or polysorbate-coated polystyrene (P80-PS) nanoparticles (100 nm or 200 nm in diameter) in olfactory and respiratory nasal epithelia and olfactory bulbs in mice.
View Article and Find Full Text PDFAdvances in biotechnology have now created a capacity to produce therapeutically active proteins on a commercial scale, opening the potential for their application in an array of disease conditions. The process of translation of the variety of different therapeutic proteins into the medicines used in clinics is now occurring. To assist in this translation, new formulations to deliver proteins could play an important role.
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