Polysaccharide-coated Liposomes Research Articles

Effects of gastrointestinal digestion on the cell bioavailability of sodium alginate coated liposomes containing DPP-IV inhibition active collagen peptides

Delivery matrices in foods need to be carefully designed for optimal delivery and to ensure that beneficial compounds are subsequently absorbed in the gut. It has been found that polysaccharide coating improved the cellular uptake of liposomes, but there is a lack of research on the effect of digestion on the cellular uptake of polysaccharide-coated liposomes. Herein, the sodium alginate-coated liposomes were prepared, combination of Caco-2, HT29 and Caco-2/HT29 cell models were used to assess the effect of digestion behavior on the bioavailability. Where, the bioavailability of digested liposomes was 1.60 times higher than that of undigested liposomes. Specifically, digestion firstly improved the ability of liposomes to penetrate the mucus layer by 1.43-fold. Secondly, digestion improved the uptake of liposomes into the intestinal cells by about 1.33-fold. Next, cellular uptake mechanisms were explored using uptake inhibition experiments. Proteomics and metabolic process experiments showed that liposomes pass intact through the small intestinal epithelium into the somatic circulation. This work suggested that digestive behavior enhanced liposome bioavailability in terms of penetration through the cellular mucus layer as well as uptake capacity. These results deepen the understanding of the specific role of digestion on polysaccharide-modified liposomes and favor a better design of delivery systems.

Polysaccharide-modified liposomes and their application in cancer research.

Nanodrug delivery systems have been widely used in cancer treatment. Among these, liposomal drug carriers have gained considerable attention due to their biocompatibility, biodegradability, and low toxicity. However, conventional liposomes have several shortcomings, such as poor stability, rapid clearance, aggregation, fusion, degradation, hydrolysis, and oxidation of phospholipids. Polysaccharides are natural polymers of biological origin that exhibit structural stability, excellent biocompatibility and biodegradability, flexibility, non-immunogenicity, low toxicity, and targetability. Therefore, they represent a promising class of polymers for the modification of the surface properties of liposomes to overcome their shortcomings. In addition, polysaccharides can be readily combined with other materials to develop new composite materials. Hence, they represent the optimal choice for liposomal modification to improve pharmacokinetics and clinical utility. Polysaccharide-coated liposomes exhibit better stability, drug release kinetics, and cellular uptake than conventional liposomes. The oncologic application of polysaccharide-coated liposomes has become a research hotspot. We summarize the preparation, physicochemical properties, and antineoplastic effects of polysaccharide-coated liposomes to facilitate antitumor drug development.

Physicochemical Characterization of Hyaluronic Acid and Chitosan Liposome Coatings

Hyaluronic acid (HA) and chitosan (CH) are biopolymers that are widely used in many biomedical applications and for cosmetic purposes. Their chemical properties are fundamental to them working as drug delivery systems and improving their synergistic effects. In this work, two different protocols were used to obtain zwitterionic liposomes coated with either hyaluronic acid or chitosan. Specifically, the methodologies used to perform vesicle preparation were chosen by taking into account the specific chemical properties of these two polysaccharides. In the case of chitosan, liposomes were first synthesized and then coated, whereas the coating of hyaluronic acid was achieved through lipidic film hydration in an HA aqueous solution. The size and the zeta-potential of the polysaccharide-coated liposomes were determined by dynamic light scattering (DLS). This approach allowed coated liposomes to be obtained with hydrodynamic diameters of 264.4 ± 12.5 and 450.3 ± 16.7 nm for HA- and CH-coated liposomes, respectively. The chemical characterization of the coated liposomal systems was obtained by surface infrared (ATR-FTIR) and nuclear magnetic resonance (NMR) spectroscopies. In particular, the presence of polysaccharides was confirmed by the bands assigned to amides and saccharides being in the 1500–1700 cm−1 and 800–1100 cm−1 regions, respectively. This approach allowed confirmation of the efficiency of the coating processes, evidencing the presence of HA or CH at the liposomal surface. These data were also supported by time-of-flight secondary ion mass spectrometry (ToF-SIMS), which provided specific assessments of surface (3–5 nm deep) composition and structure of the polysaccharide-coated liposomes. In this work, the synthesis and the physical chemistry characterization of coated liposomes with HA or CH represent an important step in improving the pharmacological properties of drug delivery systems.

Modulation of Epidermal Growth Factor Release by Biopolymer-Coated Liposomes

This work describes the development of polysaccharide-coated liposomes to modulate the delivery of epidermal growth factor (EGF), with the aim to produce different EGF release profiles depending on the milieu of infected wounds. For this purpose, cationic liposomes were coated with one layer of sodium alginate (ALG) followed by one layer of chitosan (CHI) using the layer-by-layer (LbL) technique. The coated liposomes exhibited apparent hydrodynamic diameters of 278 ± 36 and 216 ± 96 nm for Lip-ALG and Lip-ALG-CHI, respectively. Thus, it appears that adding the CHI layer compacted the Lip-ALG one. The incorporation efficiency of EGF was a maximum of 55% for liposomes with a polymeric coating. In vitro release experiments showed that Lip-ALG-CHI exhibits a higher release rate constant under acidic pH conditions, resembling those of infected tissue. Using an ex vivo model of EGF release in porcine ear skin, these liposomes were found to accumulate in the epidermis. Thus, coated liposomes could represent a local EGF delivery mechanism to promote healing.

Liposomal Form of the Echinochrome-Carrageenan Complex

Inclusion of drugs in liposomes offers the potential for localized and sustained delivery to mucosal surfaces. The inclusion of the carrageenan matrix with echinochrome A ((Ech)—the active substance of the drug Histochrome) in liposomes was studied. According to the spectral characteristics, Ech was not oxidized and retained stability after encapsulation in the liposomes and the lyophilization process. Loading the liposomes with negatively charged polysaccharide results in the increase in the zeta potential to more negative values (from −14.6 to −24.4 mV), that together with an increasing in the sizes of liposomes (from 125.6 ± 2.5 nm to 159.3 ± 5.8 nm) propose of the formation of the polymer coating on liposomes. The interactions of liposomes with porcine stomach mucin was determined by the DLS and SEM methods. The changes in the zeta-potential and size of the mucin particles were observed as the result of the interaction of liposomes with mucin. To evaluate the mucoadhesive properties of liposomes and the penetration of Ech in the mucosa, a fresh-frozen inner surface of the small intestine of a pig as a model of mucous tissue was used. Polysaccharide-coated liposomes exhibit very good mucoadhesive properties −50% of Ech remains on the mucosa.

Polysaccharide-coated liposomes by post-insertion of a hyaluronan-lipid conjugate

Hyaluronan (MW: 1.5 MDa) was linked to a phospholipid (dipalmitoyl phosphatidylethanolamine, DPPE) by an amidification procedure to obtain novel macromolecules (HA-DPPE) able to coat liposomes. Liposomes made of dipalmitoyl phosphatidylcholine and cholesterol (DPPC/Chol: 95/5 molar ratio), with a mean size around 100nm, were incubated with HA-DPPE at 55°C, allowing the insertion of DPPE moieties in the liposomal bilayer and leading to hyaluronan-coated liposomes (HAsomes) as evidenced by several techniques including dynamic light scattering and differential scanning calorimetry. The amount or HA-DPPE coating liposomes was quantified by different methods among which capillary electrophoresis and their stability in serum was finally compared to that of plain liposomes. As a conclusion, we provide insight into the physico-chemical characterization of HA-DPPE and of HAsomes demonstrating that easy coating of phospholipid vesicles can be achieved by post-insertion of a lipid derivative of hyaluronan. This approach represents an innovative strategy for coating vesicular systems to confer them simultaneously with long circulation properties and selective targeting towards HA-receptors.

Skin delivery of hydrophilic molecules from liposomes and polysaccharide-coated liposomes.

Liposomes are commonly used in cosmetic formulations to increase the bioavailability of active ingredients. We have previously shown that polysaccharide coating of liposomes improves their resistance to surfactants and electrolytes. In the current study, we have assessed the impact of coating on the skin penetration enhancer properties of liposomes. The physicochemical properties of coated liposomes (Ionosomes™) were evaluated before and after encapsulation of two different hydrophilic molecules (caffeine and a hexapeptide), and compared to those observed with non-coated liposomes. Moreover, in vitro permeation experiments were performed using Franz™-modified diffusion cells, with normal human skin as membranes. Results showed that both coated and non-coated liposomes significantly improved the bioavailability of hydrophilic active molecules in skin, compared to reference solutions. Although liposome coating slightly reduced entrapment efficiency, the delivery of active molecules was not adversely affected by the process. In conclusion, polysaccharide coating of liposomes allows for better protection of their integrity without compromising the skin bioavailability of the active molecules that they convoy.

Pectin and polygalacturonic acid-coated liposomes as novel delivery system for nisin: Preparation, characterization and release behavior

Liposome systems can increase the stability of encapsulated compounds, such as the bacteriocin nisin, improving its benefits as antibacterial agent. In this study, nanoliposomes encapsulating nisin were prepared with soy phosphatidylcholine (PC) and pectin or polygalacturonic acid. The efficiency of encapsulation was 87.9% to PC-pectin and 84.0% to PC-polygalacturonic acid nanoliposomes. The liposomes presented a well-defined spherical shape, with sizes ranging from 94 to 160 nm, showing minimal differences during storage at 7 °C or 25 °C for 28 days. The values for polydispersity index were around 0.2–0.3, and the zeta potential of polysaccharide-coated liposomes was in the range from −17 mV to −32 mV during the time of storage, indicating high physical stability. The antimicrobial activity was observed against five different strains of Listeria in milk-agar plates, with a better efficiency against L. innocua 6a. The in vitro release studies showed that the nisin release rate of PC-pectin and PC-polygalacturonic acid liposomes was lower when compared with PC liposomes, evidencing sustained-releasing potential for food applications.

Polysaccharide-coated liposomal formulations for dental targeting

The efficacy of treatments of oral ailments is often challenged by a low residence time of the conventional pharmaceutical formulations in the oral cavity, which could be improved by using bioadhesive formulations. This in vitro study investigated charged liposomes, both uncoated and coated through electrostatic deposition with polysaccharides (chitosan, alginate and pectin), as bioadhesive systems for the oral cavity. First, formulations that provided liposomes fully coated with polysaccharide were selected. Thereafter, the stability of both the uncoated and the polysaccharide-coated liposomes was investigated in artificial saliva simulating pH, ionic strength, and ionic content of natural saliva. Additionally, adsorption to hydroxyapatite (model for tooth enamel) was tested. The surface charge was of high importance for both the stability in salivary environment and bioadhesion. In artificial saliva, the negatively charged liposomes were the most stable, and the stability of the positively charged liposomes was improved through coating with a negatively charged polysaccharide. On the contrary, the positively charged liposomes were the most bioadhesive, although a moderate adsorption was recorded for the negatively charged liposomes. Based on the present results, the negatively charged liposomes seem to be the most promising formulations used as a tooth adhesive nanosystem and could as such provide improved treatment of tooth ailments.

Layer-by-layer polysaccharide-coated liposomes for sustained delivery of epidermal growth factor

A three-dimensional layer-by-layer (LbL) structure composed by xanthan and galactomannan biopolymers over dioctadecyldimethylammonium bromide (DODAB) liposome template was proposed and characterized for protein drug delivery. The polymers and the surfactant interaction were sufficiently strong to create a LbL structure up to 8 layers, evaluated using quartz crystal microbalance (QCM) and zeta potential analysis. The polymer–liposome binding enthalpy was determined by isothermal titration calorimetry (ITC). The bilayer of biopolymer-coated liposomes with diameters of 165 (±15)nm, measured by dynamic light scattering (DLS), and ζ-potential of −4 (±13)mV. These bilayer-coated nanoparticles increased up to 5 times the sustained release of epidermal growth factor (EGF) at a first order rate of 0.005min−1. This system could be useful for improving the release profile of low-stability drugs like EGF.

Control in Mineralization by the Polysaccharide-Coated Liposome via the Counter-Diffusion of Ions

We created an organic–inorganic hybrid nanocapsule by utilizing polysaccharide-coated liposomes as a reaction site for the deposition of calcium phosphate (CaP). Phosphate ions were encapsulated in a liposome, followed by the layer-by-layer deposition of chitosan (CHI), dextran sulfate (DXS), or DNA onto the liposome surface. Calcium ions were added to an aqueous suspension of the phosphate ion-incorporated nanocapsules to prepare the nanocapsules that provide a variety of walls for the counter-diffusion of ions and the surface for CaP deposition. As a result, control in biomineralization, such as thickness and crystal properties, over the nanocapsules was achieved by tuning the counter-diffusion of the calcium ions and the phosphate ions through the capsule wall and the surface chemical composition of nanocapsules. Furthermore, we carried out DNA adsorption onto CaP-coated liposomes. DNA was releasable from the nanocapsules because of the dissolution of CaP under acidic conditions.

Novel O-palmitoylscleroglucan-coated liposomes as drug carriers: Development, characterization and interaction with leuprolide

Polysaccharide-coated liposomes have been studied for their potential use for peptide drug delivery by the oral route because they are able to minimize the disruptive influences on peptide drugs of gastrointestinal fluids. The aim of this work was to synthesize and characterize a modified polysaccharide, O-palmitoylscleroglucan (PSCG), and to coate unilamellar liposomes for oral delivery of peptide drugs. To better evaluate the coating efficiency of PSCG, also scleroglucan (SCG)-coated liposomes were prepared. We studied the surface modification of liposomes and the SCG- and PSCG-coated liposomes were characterized in terms of size, shape, ζ potential, influence of polymer coating on bilayer fluidity, stability in serum, in simulated gastric and intestinal fluids and against sodium cholate and pancreatin. Leuprolide, a synthetic superpotent agonist of luteinizing hormone releasing hormone (LHRH) receptor, was chosen as a model peptide drug. After polymer coating the vesicle dimensions increased and the ζ potential shifted to less negative values. These results indicate that both SCG- and PSCG-coated liposomes surface and DSC results showed that PSCG was anchored on the liposomal surface. The stability of coated-liposomes in SGF, sodium cholate solution and pancreatin solution was increased. From this preliminary in vitro studies, it seems that PSCG-coated liposomes could be considered as a potential carrier for oral administration.

Partition of polysaccharide-coated liposomes in aqueous two-phase systems

Hydrophobized polysaccharides such as cholesterol-bearing pullulan (CHP), dextran (CHD) and mannan (CHM) effectively coat the liposomal surface. Partition of the hydrophobized polysaccharide-coated liposomes in an aqueous two-phase system (PEO (top)/pullulan (bottom) or PEO (top)/dextran (bottom)) was investigated (PEO = poly(ethylene oxide)). Conventional liposomes without a polysaccharide coat mostly locate at the interface between the two polymer phases. The polysaccharide-coated liposomes, on the other hand, were partly partitioned to the bottom polysaccharide phase depending on the structure of the hydrophobized polysaccharide on the liposomal surface. The affinity between the polysaccharide on the liposomal surface and that in the bulk bottom phase controls the efficiency of partition. The sequence of interaction strength between the two carbohydrates as the following: for the PEO/dextran two-phase system, dextran (liposome)-dextran (bulk) > mannan (liposome)-dextran (bulk) > pullulan ( liposome) - dextran ( bulk) ; while for the PEO/pullulan system, the sequence of interaction strength was pullulan (liposome)-pullulan (bulk) > dextran (liposome)-pullulan (bulk) ≈ mannan ( liposome) - pullulan ( bulk) .

脳腫よう指向性リポソームの開発

Liposomes were investigated as a carrier for the delivery of therapeutic agents to target brain tumors. We have developed the coating of liposomes with pullulan and 1-aminolactose pullulan, and compared with conventional neutral liposome. When pullulan-coated liposome labeled with 14C was intracarotidly administrated into the 9L cells immlanted brain tumor rats, brain tumor uptake of radioactivity increased 4.5 times and spleen uptake decrease compared with the neutral liposome. The cytotoxity of cisplatin against 9L-glioma cells was not inhibited by encapsulation of pullulan-coated liposmes. The quantity of platinum of 1-aminolactose pullulan-coated liposome-encapsulated cisplatin into the brain tumor was about 4 times as great as that of pullulan-coated liposome-encapsulated cisplatin. Considering that polysaccharide-coated liposomes become more stable, both physiochemically and biochemically, than conventional liposomes, 1-aminolactose pullulan-coated liposomes may be useful in targeting brain tumors.

ガラクトース残基を有する多糖被覆リポソームを用いた肝癌化学療法への基礎的検討

Although normal liver parenchymal cells have galactose-specific asialoglycoprotein receptors, little is known about the other regulatory factors except for terminal non-reduced galactose. We investigated the in-vitro uptake of liposomes coated with polysaccharides (pullulan)(control), galactosamine pullulan, and 1-amino-lactose pullulan into a rat hepatoma cell line(AH66 cells)and isolated rat hepatocytes(parenchymal cells). The uptake of 1-amino-lactose pullulan into AH66 cells was about 1.4 times as great as that of pullulan, and that of galactosamine pullulan about 1.2 times as great. The uptake of these substances into hepatocytes, however, was almost the same as that of pullulan. Consequently the elevated uptake of pullulan with galactose groups into AH66 cells might not be connected with galactose receptors. However, it is also possible that the viability of AH66 cells and isolated hepatocytes in vitro might be different, Considering that polysaccharide-coated liposomes become more stable, both physiochemically and biochemically, than conventional liposomes, 1-amino-lactose pullulan coated liposomes may be useful in targeting hepatoma cells.

Cell Specificity of Polysaccharide Derivatives on Liposomal Surface

Abstract Various pullulan derivatives, which have both cholesterol and another monosaccharide terminal such as hexosamines and 1-aminohexoses, were synthesized and employed for coating liposome. The lectin-induced aggregation and the phagocyte uptakes of such polysaccharide-coated liposomes were effectively controlled by changing only the terminal sugar residue of polysaccharide derivatives.

分子認識素子を付与したリポソームの特異細胞への指向性

We have developed the coating of liposomes with a cell specific polysaccharide. Carbohydrates play a very important role in biological recognition system. In this study, galactosamin(1), 1-amino-galactose(2), 1-amino-mannose(3), 1-amino-glu-cose(4)was selected and partly replaced to be an effective sensory device on naturally occurring polysaccharide such as pullulan. The polysaccharide-coated liposomes become significantly stable both physicochemically and biochemically and also cell recognizable. Recognizabilities of the poly-saccharide-coated liposomes were confirmed by specific lectin-induced aggregation, cell-liposome interaction, and tissue distribution. Liposomes coated with pullulan derivatives(1-3)were effectively endocytosed by human neutrophils and monocytes, while liposomes coated with pullulan derivative(4) inhibited the endocytosis. When galactosamin-modified pullulan-coated liposome was intravenously administrated into mice, liver uptake increased compared with the simple pullulan-coated liposome. These findings suggest that terminal sugars of modified polysaccharides act as a potentially valuable sensory device of drug delivery system.

Targeting Cancer therapy in Mice by Use of Newly Developed Immunoliposomes Bearing Adriamycin

AbstractPolysaccharide-coated liposomes have been developed to improve the stability of conventional liposomes against biochemical and physicochemical stimuli. Pullulan (MW 5 × 104) was used as the polysaccharide. the mouse IgM monoclonal antibody (CSLEX 1) recognizes a sialosylated Lex, which is a tumor-specific antigen in athymic mice. the IgM antibody was reduced with cysteine to obtain the subunit (IgMs) that remained biologically active. the IgMs was accumulated in an antigen-positive tumor in vivo. Subsequently, it was conjugated with the pullulan-coated liposome to form an immunoliposome.Tissue distribution studies demonstrated that immunoliposomes were more efficiently targeted to an implanted tumor than to the polysaccharide-coated liposomes. This is accompanied by a drastic decrease in liver uptake of the immunoliposomes. Furthermore, adriamycin-encapsulated immunoliposomes in-hibited the growth of the implanted tumor more effectively than did the simple pulluian-coated liposomes.

Possible eye-irritant test using polysaccharide-coated liposomes as a corneal epithelium model.

An alternative nonanimal test to the Draize test to evaluate the eye irritancy of surfactants has been newly developed. The physicochemical lysis of liposomal membranes by various surfactants, such as sodium dodecyl sulfate (SDS), dodecyldimethylbenzylammonium chloride (BTC), tetradecyldimethylbenzylammonium chloride (Sanisol M-100), benzyldimethy1-2- (2-p-1, 1, 3, 3-tetramethylbutylphenoxy) ethoxyethylammonium chloride (Hyamine 1622), dodecanoyldiethanolamide (LDE), and polyoxyethylene (n=21) -sorbitan monostearate (Tween 80), was correlated with the results of the Draize test with the same surfactants. Egg phosphatidylcholine small unilamellar vesicles (SUVs) coated with O-palmitoylamylopectinsulfonic acid were employed as a model of the human corneal epithelium. The lysis of liposomes with the surfactants was monitored quantitatively by following the release of carboxyfluorescein (CF) from the interior water phase of the liposomes suspended in an aqueous medium containing almost the same salt composition as that in the human tear film. The order of efficiencies of these surfactants in perturbing the liposomal membrane was Sanisol M-100 > Hyamine 1622 >BTC> (Tween 80>) LDE>SDS. With the exception of Tween 80, whose critical micelle concentration (cmc) is relatively low (9.6 × 10-6M) compared with those of the other surfactants (approximately 5-7× 10-4M), a reliable correlation was found between the results of animal and nonanimal tests.

Macrophage Activation by Poly(maleic acid-alt-2-cyclohexyl-1,3-dioxap-5-ene) Encapsulated in Polysaccharide-Coated Liposomes

An increase in the efficiency of macrophage activation has been tried by en capsulating potent polyanionic polymer immunomodulators into polysac charide-coated liposomes. For this purpose, several alternating copolymers of maleic acid (MA) and itaconic acid (IT) with 2-cyclohexyl-1,3-dioxap-5-ene (CDA), styrene (ST), and other monomers have been synthesized and frac tionated. First, the interaction between the liposomes and polyanionic polymers was investigated. As a result, poly(maleic acid-alt-2-cyclohexyl-1,3-dioxap-5-ene) (MA-CDA) was found to be the best candidate for encapsulating in the liposome while poly(itaconic acid-alt-styrene)(IA-ST) strongly perturbed these vesicles. Based on these results, MA-CDA was encapsulated in the mannan derivative- coated liposomes and the macrophage activation activity was evaluated from the superoxide production of the activated macrophages in vivo. Compared with the administration of free MA-CDA, the maximum in the superoxide pro duction appeared faster (2 h after injection) and the activity was significantly increased.