Superiority of DEAE-Dx-Stabilized Cationic Bile-Based Vesicles over Conventional Vesicles for Enhanced Hepatic Delivery of Daclatasvir.

The purpose of our study was to improve the delivery of a direct-acting antiviral drug, daclatasvir, to the site of action, liver tissues, using physically and biologically stable cationic bile-based vesicles. Accordingly, cationic bile-based vesicles were prepared as pro-bile-based vesicles and diethylaminoethyl dextran (DEAE-Dx)-stabilized bile-based vesicles to increase their stability without negatively affecting their hepatic affinity. The prepared bile-based vesicles were characterized for particle size, polydispersity index, ζ-potential, in vitro daclatasvir release, and ex vivo permeation using non-everted gut sac intestine. The in vivo biodistribution was experimented after oral administration utilizing the radiolabeling assay, where the liver showed the highest accumulation of the DEAE-Dx-stabilized bile-based vesicles after 4 h, reaching a value of 4.6% ID/g of the total oral administered dose of the labeled drug compared to drug solution, pro-bile-based vesicles, and cationic bile-based vesicles where the accumulation was 0.19, 1.3, and 0.31% ID/g, respectively. DEAE-Dx-stabilized bile-based vesicles increased the drug deposition into the liver about 42-fold compared to oral solution. The high physical stability and the high resistance to opsonization and clearance show that DEAE-Dx-stabilized bile-based vesicles could be efficiently applied for enhancing daclatasvir delivery to the liver after oral administration.

How Nanoparticle Physicochemical Parameters Affect Drug Delivery to Cells in the Retina via Systemic Interactions.

Minor changes in the composition of poloxamer 188-modified, DEAE-dextran-stabilized (PDD) polybutylcyanoacrylate (PBCA) nanoparticles (NPs), by altering the physicochemical parameters (such as size or surface charge), can substantially influence their delivery kinetics across the blood-retina barrier (BRB) in vivo. We now investigated the physicochemical mechanisms underlying these different behaviors of NP variations at biological barriers and their influence on the cellular and body distribution. Retinal whole mounts from rats injected in vivo with fluorescent PBCA NPs were processed for retina imaging ex vivo to obtain a detailed distribution of NPs with cellular resolution in retinal tissue. In line with previous in vivo imaging results, NPs with a larger size and medium surface charge accumulated more readily in brain tissue, and they could be more easily detected in retinal ganglion cells (RGCs), demonstrating the potential of these NPs for drug delivery into neurons. The biodistribution of the NPs revealed a higher accumulation of small-sized NPs in peripheral organs, which may reduce the passage of these particles into brain tissue via a "steal effect" mechanism. Thus, systemic interactions significantly determine the potential of NPs to deliver markers or drugs to the central nervous system (CNS). In this way, minor changes of NPs' physicochemical parameters can significantly impact their rate of brain/body biodistribution.

Formulation studies on ibuprofen sodium-cationic dextran conjugate: effect on tableting and dissolution characteristics of ibuprofen.

The effect of electrostatic interaction between ibuprofen sodium (IbS) and cationic diethylaminoethyl dextran (Ddex), on the tableting properties and ibuprofen release from the conjugate tablet was investigated. Ibuprofen exhibits poor flow, compaction (tableting) and dissolution behavior due to its hydrophobic structure, high cohesive, adhesive and viscoelastic properties therefore it was granulated with cationic Ddex to improve its compression and dissolution characteristics. Electrostatic interaction and hydrogen bonding between IbS and Ddex was confirmed with FT-IR and DSC results showed a stepwise endothermic solid-solid structural transformation from racemic to anhydrous forms between 120 and 175 °C which melted into liquid form at 208.15 °C. The broad and diffused DSC peaks of the conjugate granules as well as the disappearance of ibuprofen melting peak provided evidence for their highly amorphous state. It was evident that Ddex improved the flowability and densification of the granules and increased the mechanical and tensile strengths of the resulting tablets as the tensile strength increased from 0.67 ± 0.0172 to 1.90 ± 0.0038 MPa with increasing Ddex concentration. Both tapping and compression processes showed that the most prominent mechanism of densification were particle slippage, rearrangement and plastic deformation while fragmentation was minimized. Ddex retarded the extent of dissolution in general, indicating potentials for controlled release formulations. Multiple release mechanisms including diffusion; anomalous transport and super case II transport were noted. It was concluded that interaction between ibuprofen sodium and Ddex produced a novel formulation with improved flowability, tableting and dissolution characteristics with potential controlled drug release characteristics dictated by Ddex concentration.

Controlled Electrostatic Self-Assembly of Ibuprofen-Cationic Dextran Nanoconjugates Prepared by low Energy Green Process - a Novel Delivery Tool for Poorly Soluble Drugs.

PURPOSE: The direct effect of electrostatic interaction between ibuprofen and cationic dextran on the system-specific physicochemical parameters and intrinsic dissolution characteristics of ibuprofen was evaluated in order to develop drug-polymer nanoconjugate as a delivery strategy for poorly soluble drugs. METHODS: Amorphous ibuprofen-DEAE dextran (Ddex) nanoconjugate was prepared using a low energy, controlled amphiphile-polyelectrolyte electrostatic self-assembly technique optimized by ibuprofen critical solubility and Ddex charge screening. Physicochemical characteristics of the nanoconjugates were evaluated using FTIR, DSC, TGA, NMR and SEM relative to pure ibuprofen. The in vitro release profiles and mechanism of ibuprofen release were determined using mathematical models including zero and first order kinetics; Higuchi; Hixson-Crowell and Korsmeyer-Peppas. RESULTS: Electrostatic interaction between ibuprofen and Ddex was confirmed with FT-IR, (1)H NMR and (13)C NMR spectroscopy. The broad and diffused DSC peaks of the nanoconjugate as well as the disappearance of ibuprofen melting peak provided evidence for their highly amorphous state. Low concentrations of Ddex up to 1.0 × 10(-6) g/dm(3) enhanced dissolution of ibuprofen to a maximum of 81.32% beyond which retardation occurred steadily. Multiple release mechanisms including diffusion; discrete drug dissolution; anomalous transport and super case II transport were noted. CONCLUSIONS: Controlled assembly of ibuprofen and Ddex produced a novel formulation with potential extended drug release dictated by Ddex concentration.

Sequential diethylaminoethyl dextran-grafting and diethylaminoethyl modification improve the adsorption performance of anion exchangers.

Ion exchangers with high adsorption capacity, fast mass transfer, and high salt-tolerance synchronously are highly desired for high-performance protein purification. Here, we propose a sequential diethylaminoethyl dextran-grafting and diethylaminoethyl chloride modification strategy to achieve high-performance anion exchangers. The advantages of the double-modification strategy lie in: (1) the introduction of diethylaminoethyl in the second modification has no diffusion limitation due to the small molecular size, thus a high ionic capacity; (2) the grafting ligands not only provide three-dimensional adsorption space for high adsorption capacitybut alsofacilitate surface diffusion of protein by chain delivery. The maximum adsorption capacity of the obtained anion exchangers for bovine serum albumin reaches 333 mg/mL, the ratio of effective pore diffusivity (De) to free solution diffusivity (D0) reaches 0.69, and the adsorption amount reaches 97 mg/mL even in 100 mmol/L NaCl concentration,. All these results demonstrate the proposed sequential modification strategy are promising for the preparation of high-performance ion exchangers.

Photodegradation of environmental mutagens by visible irradiation in the presence of xanthene dyes as photosensitizers.

The photodegradation of environmental mutagens, such as 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC), and 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), was investigated by visible irradiation in the presence of xanthene dyes as photosensitizers. Although the environmental mutagens themselves were very stable during visible irradiation under the conditions in this study, they were effectively photodegraded in the presence of the xanthene dyes (erythrosine, rose bengal, and phloxine). Moreover, photodegradation of the mutagens was further enhanced for xanthene dyes loaded onto a water-soluble diethylaminoethyl (DEAE)-dextran anion-exchanger via ionic interactions (xanthene-dyeDEX). Photodegradation was inhibited by O2 removal from the reaction solution. In ESR spin-trapping experiments using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a trapping reagent, signals characteristic of DMPO-•OH (hydroxyl radical) were observed in the presence of xanthene-dyeDEX. These results suggest that reactive oxygen species derived from O2, such as singlet molecular oxygen (•1O2) and/or •OH, were active participants in photodegradation of the mutagens in the presence of xanthene dyes or xanthene-dyeDEX.

Design and characterization of calcium alginate microparticles coated with polycations as protein delivery system.

Bovine serum albumin (BSA) loaded calcium alginate microparticles (MPs) produced in this study by a w/o emulsification and external gelation method exhibited spherical and fairly smooth and porous morphology with 1.052 ± 0.057 µm modal particle size. The high permeability of the calcium alginate hydrogel lead to a potent burst effect and too fast protein release. To overcome these problems, MPs were coated with polycations, such as chitosan, poly-L-lysine and DEAE-dextran. Our results demonstrated that coated MPs showed slower release and were able to significantly reduce the release of BSA in the first hour. Therefore, this method can be applied to prepare coated alginate MPs which could be an optimal system for the controlled release of biotherapeutic molecules. Nevertheless, further studies are needed to optimize delivery properties which could provide a sustained release of proteins.

Coacervate microdroplet protocell-mediated gene transfection for nitric oxide production and induction of cell apoptosis.

Liquid coacervate microdroplets have been widely explored as membrane-free compartment protocells for cargo delivery in therapeutic applications. In this study, coacervate protocells were developed as gene carriers for transfection of nitric oxide synthase (NOS) and overproduction of nitric oxide (NO) for killing of cancer cells. The coacervate microdroplet protocells were formed via the liquid-liquid phase separation of oppositely charged diethylaminoethyl-dextran/polyacrylic acids. The coacervate microdroplet protocells were found to facilitate gene transfection, which was demonstrated by cell imaging of the internalized coacervate microdroplets containing plasmids of enhanced green fluorescent protein. Due to their high transfection capability, the coacervate protocells were subsequently utilized for the delivery of NOS plasmids (pNOS). The cellular internalization of pNOS-containing coacervate carriers was found to result in high NOS expression coupled with NO overproduction, which then induced cell apoptosis and decreased cell viability. The cell apoptosis is associated with NO-mediated mitochondrial damage. The enhanced gene transfection was attributed to coacervate microdroplets' unique high sequestration capability and liquid-like fluidity. Overall, the incorporation of genes in coacervate microdroplets was demonstrated as a viable and novel strategy for the development of cargo biocarriers for biomedical applications.

Poly(I:C) coated PLGA microparticles induce dendritic cell maturation.

Microparticles from poly(D,L-lactic-co-glycolic acid) [PLGA] are of steadily rising interest for the delivery of antigens to immune cells and the induction of a long-lasting immune response for vaccination or immunological tumor therapy. However, if the desired vaccine contains only weak antigens and fails to activate the antigen presenting cells (APC), the opposite effect, i.e., the induction of immunotolerance may be observed. Therefore, it was the aim of this study to show the ability of protein loaded PLGA microparticles to additionally carry a specific, surface-coated maturation signal to human dendritic cells (DC), i.e., the most potent APC. Polyinosine-polycytidylic acid [poly(I:C)], a ligand of Toll-like receptor (TLR) 3, was efficiently bound either in a single layer or a multilayer attempt to the surface of diethylaminoethyl dextran modified PLGA microparticles. These particles were effectively phagocytized by DC ex vivo and induced a maturation similar to that achieved with a cytokine cocktail or higher concentrations of soluble poly(I:C). In conclusion, the concept of surface coating of biodegradable microparticles with selected TLR ligands might successfully be used in DC-based cell therapies for cancer or in vaccination trials to induce DC maturation and specifically amplify the immunological response to encapsulated antigens.

Single-Step Purification of Calpain-1, Calpain-2, and Calpastatin Using Anion-Exchange Chromatography.

Purification and separation of calpains and calpastatin are used to determine the individual activities of calpain-1 and calpain-2 and their inhibitor calpastatin. We discuss here a method to purify these enzymes using dialysis followed by separation using anion-exchange chromatography coupled with gradient elution. Swollen DEAE Sephacel is used as the column matrix in this method. Calpastatin and both domains of calpain are weakly basic molecules that effectively bind with the DEAE Sephacel and separate well using a stepwise, increasing gradient of NaCl to elute the proteins. Calpastatin binds most weakly with the column matrix, so it elutes first, followed by calpain-1 and, finally, calpain-2.

Investigation of charge ratio variation in mRNA - DEAE-dextran polyplex delivery systems.

mRNA pharmaceuticals represent a new class of therapeutics, with applications, in cancer vaccination, tumour therapy and protein substitution. Formulations are required to deliver messenger RNA (mRNA) to the target sites where induction of genetic transfection following receptor mediated cell uptake & translation is required. In the current study, the cationic polysaccharide diethylaminoethylen (DEAE) - Dextran was selected as a model system carrier for the investigation of polyplex nanoparticle formation together with mRNA as a function of the molar ratio of the components. The structure of the mRNA/Dextran colloids was investigated as a function of the polymer-to-mRNA ratio and correlated with the biological activity determined by cellular transfection with luciferase coding mRNA. Dynamic light scattering (DLS), small angle x-ray scattering (SAXS), and small angle neutron scattering (SANS) with deuterium contrast variation were used to achieve structural insight into the systems. Similarly to previously investigated lipid based systems, colloidally stable particles with confined size were obtained with either excess of positive or negative charge. Highest activity was obtained with positive charge excess. From the scattering experiments information on the internal organization inside the polymer/mRNA systems was derived. Indication for the presence of structural elements in the length scale of ten to 20 nm were found in the excess of dextran, which could be due to either excess or particulate polymer. Information on the molecular organization of the mRNA nanoparticle products may provide a valuable basis for defining critical quality attributes of drug products for pharmaceutical application.

Identification of gangliosides recognized by IgG anti-GalNAc-GD1a antibodies in bovine spinal motor neurons and motor nerves.

The presence of immunoglobulin G (IgG)-type antibodies to the ganglioside, N-acetylgalactosaminyl GD1a (GalNAc-GD1a), is closely associated with the pure motor type of Guillain-Barré syndrome (GBS). In the present study, we isolated disialogangliosides from the motor neurons and motor nerves of bovine spinal cords by DEAE-Sephadex column chromatography. The disialoganglioside fraction contained GD1a, GD2, GD1b, and three gangliosides, designated X1, X2 and X3. Serum from a patient with axonal GBS with IgG anti-GalNAc-GD1a antibody yielded positive immunostaining with X1, X2, and X3. When isolated by preparative thin-layer chromatography (TLC), X1 migrated at the same position as GalNAc-GD1a from Tay-Sachs brain, suggesting that X1 is GalNAc-GD1a containing N-acetylneuraminic acid (NeuAc). TLC of isolated X2 revealed that it migrated between GD1a and GD2. On the other hand, X3 had a migratory rate on TLC between and GD1b and GT1b. Since both X2 and X3 were recognized by IgG anti-GalNAc-GD1a antibody, the results suggest that X2 is a GalNAc-GD1a species containing a mixture containing a NeuAc-and an N-glycolylneuraminic acid (NeuGc) species, and X3 is a GalNAc-GD1a species with two NeuGc. This evidence indicating the specific localization of GalNAc-GD1a and its isomers in spinal motor neurons should be useful in elucidating the pathogenic role of IgG anti-GalNAc-GD1a antibody in pure motor-type GBS.

Transfection Mediated by DEAE-Dextran.

Here, we describe two variations on the classical DEAE-dextran transfection procedure. The first involves a brief exposure of cells to a high concentration of DEAE-dextran and yields higher transfection frequencies but elevated cellular toxicity. The second involves a longer exposure of cells to a lower concentration of DEAE-dextran, which produces lower transfection frequencies but increased cell survival.

A robust control system for targeting melanoma by a supermolecular DDMC/paclitaxel complex.

A DEAE-dextran-MMA copolymer (DDMC)-paclitaxel (PTX) conjugate was prepared using PTX as the guest and DDMC as the host. The resistance of B16F10 melanoma cells to PTX was confirmed, while the DDMC-PTX conjugate showed excellent anticancer activity that followed the Hill equation. The robustness in the tumor microenvironment of the allosteric system was confirmed via BIBO stability. This feedback control system, explained via a transfer function, was very stable and showed the sustainability of the system via a loop, and it showed superior anti-cancer activity without drug resistance from cancer cells. The block diagram of this signal system in the tumor microenvironment used its loop transfer function G(s) and the dN(s) of the external force. This indicial response is an ideal one without a time lag for the outlet response. The cell death rate of DDMC-PTX is more dependent on the Hill coefficient n than on the Michaelis constant Km. This means that this supermolecular reaction with tubulin follows an "induced fit model".

DEAE-Dextran coated paclitaxel nanoparticles act as multifunctional nano system for intranuclear delivery to triple negative breast cancer through VEGF and NOTCH1 inhibition.

Triple negative breast cancer revolution has identified a plethora of therapeutic targets making it apparent that a single target for its treatment could be rare hence creating an urge to develop robust technologies for combination drug therapy. Paclitaxel, hailed as the most significant advancement in chemotherapy faces several underpinnings due to its low solubility and permeability. Advancing research has demonstrated the role of interferons in cancer. DEAE-Dextran, an emerging molecule with evidence of interferon induction was utilized in the present study to develop a nanoformulation in conjugation with paclitaxel to target multiple therapeutic pathways, with diminution of paclitaxel adverse effects and develop a specific targeted nano system. Evidently, it was demonstrated that DEAE-Dextran coated nanoformulation portrays significant synergistic cytotoxicity in the various cell lines. Moreover, overcoming the activation of ROS by paclitaxel, the combination drug therapy more effectively inhibited ROS through ß-interferon induction. The nanoformulation was further conjugated to FITC for internalization studies which subsequently indicated maximum cellular uptake at 60min post treatment demonstrated by green fluorescence from FITC lighting up the nuclear membrane. Precisely, the mechanistic approach of nuclear-targeted nanoformulation was evaluated by in vivo xenograft studies which showed a synergistic release of ß-interferon at the target organ. Moreover, the combination nanoformulation inculcated multiple mechanistic approaches through VEGF and NOTCH1 inhibition along with dual ß and γ-interferon overexpression. Overall, the combination therapy may be a promising multifunctional nanomaterial for intranuclear drug delivery in TNBC.

DEAE-Dextran Transfection.

Biochemical methods of transfection, including calcium phosphate-mediated and diethylaminoethyl (DEAE)-dextran-mediated transfection, have been used for many years to deliver nucleic acids into cultured eukaryotic cells. Here, we briefly review the use of DEAE-dextran in transfection.

Characteristics of DEAE-dextran-MMA graft copolymer as a nonviral gene carrier.

A stable and soapless latex of diethylaminoethyl-dextran-methyl methacrylate (DEAE-dextran-MMA) graft copolymer (DDMC) has been developed for nonviral gene delivery vectors that are possible to autoclave. DDMC relatively easily formed a polyion complex between DNA and DDMC by the hydrophobic force of graft poly(MMA) depending on its large positive entropy change (DeltaS). DDMC has been confirmed as having a high protection facility for DNase by DNase degradation test.Transfection activity was determined using the beta-galactosidase assay, and a higher value of 16 times or more was confirmed for the DDMC samples in comparison with one of the starting DEAE-dextran hydrochloride samples. The resulting DDMC, having an amphiphilic domain so as to form a polymer micelle, should become a stable latex with a hydrophilic-hydrophobic microseparated domain. The complex of DDMC and plasmid DNA may be formed on the spherical structure of the amphiphilic microseparated domain of DDMC and have a good affinity to the cell membrane. The infrared absorption spectrum shift to a high-energy direction at around 3450 cm(-1), because of the complexes between DNA and DDMC, may cause the formation of more compact structures, not only by a coulomb force between the phosphoric acid of DNA and the DEAE group of DEAE-dextran copolymer but also by a force from the multi-intermolecule hydrogen bond in the backbone polymer DEAE-dextran and a hydrophobic force from the graft poly(MMA) in DDMC. It is thus concluded that DNA condensation may possibly have a high transfection efficiency via DDMC. The high efficiency of this graft copolymer, which is sterilized by an autoclave, may thus make it a valuable tool for safe gene delivery.

In vivo drug release from hydrophilic dextran tablets capable of forming polyion complex.

The aim of this comparative study was to investigate the in vivo drug release property of hydrophilic dextran tablets with or without swelling in the upper gastrointestinal tract (GIT) in humans. Two kinds of theophylline (TH) tablets were prepared by direct compression from a mixture of carboxymethyldextran and [2-(diethylamino)ethyl]dextran as a matrix capable of forming polyion complex (PIC-tablet), and a mixture of low and medium molecular weight hydroxypropylcellulose as a representative hydrophilic matrix (HPC-tablet). In these tablets, in vitro drug release behaviors and saliva TH level profiles after oral administration to humans were similar to each other, indicating equivalent AUC value. The tablets were then coated with Eudragit S100, enteric-coating polymer, by a dipping method in order to reveal drug release without full swelling in the upper GIT. Although the two enteric-coated tablets showed a similar in vitro release pattern, saliva level profiles were quite different as reflected in AUC values of 16.4 and 4.68 microg h/ml for enteric-coated PIC- and enteric-coated HPC-tablet, respectively. These results demonstrated that HPC-tablet could not release sufficiently without swelling in the upper GIT. In contrast, enteric-coated PIC-tablet showed an equivalent AUC value to PIC-tablet, indicating that TH was released well even in the lower GIT.

Co-precipitation of DEAE-dextran coated SPIONs: how synthesis conditions affect particle properties, stem cell labelling and MR contrast.

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely used as contrast agents for stem cell tracking using magnetic resonance imaging (MRI). The total mass of iron oxide that can be internalised into cells without altering their viability or phenotype is an important criterion for the generation of contrast, with SPIONs designed for efficient labelling of stem cells allowing for an increased sensitivity of detection. Although changes in the ratio of polymer and iron salts in co-precipitation reactions are known to affect the physicochemical properties of SPIONs, particularly core size, the effects of these synthesis conditions on stem cell labelling and magnetic resonance (MR) contrast have not been established. Here, we synthesised a series of cationic SPIONs with very similar hydrodynamic diameters and surface charges, but different polymer content. We have investigated how the amount of polymer in the co-precipitation reaction affects core size and modulates not only the magnetic properties of the SPIONs but also their uptake into stem cells. SPIONs with the largest core size and lowest polymer content presented the highest magnetisation and relaxivity. These particles also had the greatest uptake efficiency without any deleterious effect on either the viability or function of the stem cells. However, for all particles internalised in cells, the T2 and T2* relaxivity was independent of the SPION's core size. Our results indicate that the relative mass of iron taken up by cells is the major determinant of MR contrast generation and suggest that the extent of SPION uptake can be regulated by the amount of polymer used in co-precipitation reactions. Copyright © 2016 John Wiley & Sons, Ltd.