Chitosan-coated Liposomes Research Articles

Preparation and evaluation of a chitosan-coated antioxidant liposome containing vitamin C and folic acid

Vitamin C (VC) and folic acid (FA) are the important nutrient and antioxidant in human body. In order to improve their stability, their co-loaded liposomes (VCFA-Lip) and chitosan-coated liposomes (CS-VCFA-Lip) are prepared and characterised. The mean particle size of VCFA-Lip and CS-VCFA-Lip is 138 nm and 249 nm, respectively. The encapsulation efficiencies of both drugs for CS-VCFA-Lip are much higher than those for VCFA-Lip. Furthermore, the experimental results show that the antioxidant activity of CS-VCFA-Lip is higher than that of VCFA-Lip. Moreover, the storage stability study reveals that the chitosan coating can efficiently improve the physical stability of VCFA-Lip. These results indicate that stability of VC and FA can be greatly improved after being wrapped by liposomes. In addition, the performance of CS-VCFA-Lip is better than VCFA-Lip, indicating CS-VCFA-Lip can be applied as a promising delivery system for the antioxidant defence system to the food industry and cosmetic industry.

Eudragit S-100 Encapsulated Chitosan Coated Liposomes Containing Prednisolone for Colon Targeting: In vitro, Ex vivo and In vivo Evaluation

Objective: The present study was carried out to design an efficient formulation to target the drug loaded liposomes exclusively to the inflamed colonic region by protecting the payload from releasing in the upper gastro intestinal tract (GIT) by using two polymers. Methods: Liposomes were prepared by lipid film hydration method followed by chitosan coating and finally encapsulation with eudragit S-100. The coated as well as uncoated liposomes were characterized for entrapment efficiency, size and surface charge. In vitro drug release study was carried out using three step pH gradient method. Acetic acid was used to induce colitis. Ex vivo tissue drug entrapment study was done using excised tissues of male albino rats. In vivo efficiency study was done by comparatively studying the histopathology and myeloperoxidase (MPO) activity. Results: Formulations showed entrapment efficiency (93-91%) and size (99-290nm). Formulation showed T lag of 6 hrs and by the end of 16 th h, 82% drug release was achieved. Ex vivo studies revealed higher tissue-drug entrapment (22.58±2.52%) in inflamed colon when compared to healthy colon (22.58±2.52%). Histopathological studies showed marked reduction in inflammation in case of ECLs (eudragit encapsulated chitosan coated liposomes) treated groups than standard drug treated rats. The reduction in healing was further confirmed by the MPO assay which showed significant reduction in MPO (900.25±1.31 ng/ml) levels of ECL treated groups than standard drug treated (1990.32±2.11 ng/ml) and IBD group (2125.54±1.56 ng/ml). Conclusion: The ECLs showed site specific release of liposomes and increased accumulation of liposome entrapped drug in the inflamed colon. Key words: Acetic acid induced rat colitis, Colon targeting, Ex vivo tissue entrapment, Histopathological studies, IBD, MPO activity.

A Chitosan-Based Liposome Formulation Enhances the In Vitro Wound Healing Efficacy of Substance P Neuropeptide.

Currently, there is considerable interest in developing innovative biodegradable nanoformulations for controlled administration of therapeutic proteins and peptides. Substance P (SP) is a neuropeptide of 11 amino acids that belongs to the tachykinins family and it plays an important role in wound healing. However, SP is easily degradable in vivo and has a very short half-life, so the use of chitosan-based nanocarriers could enhance its pharmaceutical properties. In light of the above, the aim of this work was to produce and characterize chitosan-coated liposomes loaded with SP (SP-CH-LP) as novel biomaterials with potential application in mucosal wound healing. The loaded system’s biophysical properties were characterized by dynamic light scattering with non-invasive back scattering (DLS-NIBS), mixed mode measurements and phase analysis light scattering (M3-PALS) and high performance liquid chromatography with ultraviolet/visible light detection (HPLC-UV/VIS). Then, the efficacy of the obtained nanoformulations was examined via proof-of-principle experiments using in vitro cell assays. These assays showed an increment on cell motility and proliferation after treatment with free and encapsulated neuropeptides. Additionally, the effect of SP on wound healing was enhanced by the entrapment on CH-LP. Overall, the amenability of chitosan-based nanomaterials to encapsulate peptides and proteins constitutes a promising approach towards potential novel therapies to treat difficult wounds.

In-vitro digestion of curcumin loaded chitosan-coated liposomes.

Liposomes are considered a major route for encapsulation of hydrophilic and hydrophobic molecules. Chitosan coated liposomes could represent an alternative way as a carrier for delivery of drugs in human body. In this study the preparation and applicability of chitosan-coated liposomes containing curcumin as well as curcumin loaded anionic liposomes were evaluated. The applicability of the carriers was tested by means of an in-vitro digestion procedure allowing for measurement of the bioaccessibility of ingested curcumin. Values of diameter, polydispersity index and surface charge for curcumin loaded anionic liposomes obtained through dynamic light scattering and ζ-potential measurements were 129nm, 0.095 and -49mV, respectively. After chitosan-coating, diameter and polydispersity index remain unvaried while the surface charge gets positive. Slightly higher curcumin concentrations were found after the mouth and the stomach digestion phases when curcumin was loaded in anionic liposomes. On the contrary, after the intestinal phase, a higher percentage of curcumin was found when chitosan-coated liposomes were used as carrier, both in the raw digesta and in the bile salt micellar phase. It was shown that the presence of a positively charged surface allows a better absorption of curcumin in the small intestine phase, which increases the overall curcumin bioavailability. The mechanism behind these results can be understood from the composition of the different environments generated by the digestive fluids that differently interact with anionic or cationic surfaces.

Chitosan-modified cholesterol-free liposomes for improving the oral bioavailability of progesterone

Based on the structurally similar properties of progesterone and cholesterol, chitosan-coated cholesterol-free liposomes (CS-Lipo/Prog) were formulated. CS-Lipo/Prog are spherical and uniform in size (662.1±19.3nm) with positive potential (28.19±1.97mV). The average drug entrapment efficiency (EE) is approximately 80%. The in vitro release profile of CS-Lipo/Prog shows sustained release. The in vitro stability evaluation demonstrated that CS-Lipo/Prog can efficiently shield Prog from degradation in the gastrointestinal tract. CS-Lipo/Prog showed a longer MRT and higher AUC0-infinite after oral administration to mice than in the control group (progesterone-free). The relative bioavailability of CS-Lipo/Prog was higher than that of progesterone soft capsules (QINING®) and Lipo/Prog. Collectively, these findings suggest that cholesterol-free chitosan-coated liposomes are a promising alternative for improving the oral bioavailability of progesterone.

In vitro evaluation of chitosan-coated liposome containing both coenzyme Q10 and alpha-lipoic acid: Cytotoxicity, antioxidant activity, and antimicrobial activity.

Chitosan-coated liposome containing both coenzyme Q10 and alpha-lipoic acid (CCAL) was a novel multifunctional nano delivery system exhibited long-term stability at room temperature and high encapsulation efficiency. Which containing two kinds of antioxidants (coenzyme Q10 and alpha-lipoic acid) and two antibacterial agents (chitosan and alpha-lipoic acid). However, the further biocompatibility, such as cytotoxicity and antioxidant activity, and antimicrobial activity of CCAL, has not been systematically evaluated. This study aims to evaluate the cytotoxicity, antioxidant activity and antimicrobial activity of CCAL. This article evaluated the in vitro cytotoxicity and antioxidant activity of CCAL by CCK8 assay, and antimicrobial activity on Staphylococcus aureus and Escherichia coli was investigated. For antioxidant activity study, CCAL displayed significant antioxidant effect when compared with control group (P<.01). Finally, CCAL also exhibited antimicrobial activity, and CCAL showed stronger bactericidal effect with Gram-positive bacteria than Gram-negative bacteria. CCAL could be a potential antioxidant delivery system for cosmetics or pharmaceuticals without cytotoxicity and artificial preservatives free.

Development and characterization of polymer-coated liposomes for vaginal delivery of sildenafil citrate

Vaginal administration of sildenafil citrate has shown recently to develop efficiently the uterine lining with subsequent successful embryo implantation following in vitro fertilization. The aim of the present study was to develop sildenafil-loaded liposomes coated with bioadhesive polymers for enhanced vaginal retention and improved drug permeation. Three liposomal formulae were prepared by thin-film method using different phospholipid:cholesterol ratios. The optimal liposomal formulation was coated with bioadhesive polymers (chitosan and HPMC). A marked increase in liposomal size and zeta potential was observed for all coated liposomal formulations. HPMC-coated liposomes showed the greater bioadhesion and higher entrapment efficiency than chitosan-coated formulae. The in vitro release studies showed prolonged release of sildenafil from coated liposomes as compared to uncoated liposomes and sildenafil solution. Ex vivo permeation study revealed the enhanced permeation of coated relative to uncoated liposomes. Chitosan-coated formula demonstrated highest drug permeation and was thus selected for further investigations. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) confirmed the successful coating of the liposomes by chitosan. Histopathological in vivo testing proved the efficacy of chitosan-coated liposomes to improve blood flow to the vaginal endometrium and to increase endometrial thickness. Chitosan-coated liposomes can be considered as potential novel drug delivery system intended for the vaginal administration of sildenafil, which would prolong system's retention at the vaginal site and enhance the permeation of sildenafil to uterine blood circulation.

Polymer coated liposomes for use in the oral cavity – a study of the in vitro toxicity, effect on cell permeability and interaction with mucin

In this study we investigated the in vitro toxicity, impact on cell permeability and mucoadhesive potential of polymer-coated liposomes intended for use in the oral cavity. A TR146 cell line was used as a model. The overall aim was to end up with a selection of safe polymer coated liposomes with promising mucoadhesive properties for drug delivery to the oral cavity. The following polymers were tested: chitosan, low-methoxylated pectin (LM-pectin), high-methoxylated pectin (HM-pectin), amidated pectin (AM-pectin), Eudragit, poly(N-isopropylacrylamide-co-methacrylic acid) (p(NIPAAM-co-MAA)), hydrophobically modified hydroxyethyl cellulose (HM-HEC), and hydrophobically modified ethyl hydroxyethyl cellulose (HM-EHEC). With chitosan as an exception, all the systems exhibited no significant effect on cell viability and permeability at the considered concentrations. Additionally, all the formulations showed to a varying degree an interaction with mucin (BSM type I-S); the positively charged formulations exhibited the strongest interaction, while the negatively and neutrally charged formulations displayed a moderate or low interaction. The ability to interact with mucin makes all the liposomal formulations promising for oromucosal administration. Although the chitosan-coated liposomes affected the cell viability, this formulation also influenced the cell permeability, which makes it an interesting candidate for systemic drug delivery from the oral cavity.

Effective attenuation of vascular restenosis following local delivery of chitosan decorated sirolimus liposomes

Assuring the efficient local delivery via biocompatible nanosystems can be considered as a promising therapy for restenosis. The aim of the present study was preparation, in vitro characterization, and in vivo efficacy evaluation of sirolimus containing chitosan decorated liposomes for restenosis treatment. Liposomes were coated with chitosan, leading to ∼38nm increase in the particle size and a positive shift in the zeta potential from −1mV to +21mV. Chitosan modification was also confirmed by TEM, increased stability against detergent solubilization, and FTIR analyses. High entrapment efficiency (≥83%) and sustained release behaviors were demonstrated in both coated and uncoated vesicles. Compared to control groups, treatment of balloon injured rats with uncoated and chitosan-coated liposomes (50μg sirolimus) significantly reduced stenosis by 39% and 62%, respectively. The effect was also confirmed by immunohistochemical and in vivo CT angiography imaging studies. Chitosan-coated liposomes could be a novel platform for restenosis treatment.

The Applied Validated Ultraviolet-Visible Spectrophotometric Method and the Kinetic Model of the Release of Gedunin from a Chitosan-Coated Liposome

The aim of this study is to develop a simple and cost-effective ultraviolet-visible spectrophotometric method, validated according to the International Harmonization Guidelines for the determination of gedunin from a chitosan-coated liposome. The liposome was prepared using the conventional thin film hydration method. The absorption maximum in methanol was found to be 220 nm. The linearity was followed in the concentration from 5–25 μg/mL with a high correlation coefficient of 0.999. The detection and quantification limits were found to be 0.2062 and 0.6250 μg/mL. This method was shown to be precise at the intraday (relative standard deviation <0.3%) and interday (relative standard deviation <1.0539%) level and accurate with recoveries between 98.6540–99.9123% (relative standard deviation <0.4%). The results of the method robustness study indicate that the method was robust. The method was used to determine encapsulation efficiency and the release profile from a coated liposome. Kinetic models (zero order, first order, Higuchi, Hixson–Crowell, and Korsmeyer–Peppas) were used to fit the obtained release profile and to predict the in vivo performance of a Gedunin containing coated liposome.

Preparation of chitosan-coated liposomes as a novel carrier system for the antiviral drug Triazavirin

Novel method for the coating of positively charged liposomes with modified chitosan was elaborated. Liposomes were prepared by stepwise extrusion through inorganic membranes (Anotop) of 0.2 and 0.1 μm pore sizes. Chitosan derivatives were synthesized via the Ugi multicomponent reaction. Several series of liposomal compositions were produced and their properties were compared in terms of particle size, polydispersity index (PDI), zeta potential and stability. The effect of various additives was investigated and the optimal composition of the lipid film was determined. The addition of the uncharged fatty esters allowed the diameter of the liposomes obtained by extrusion to be reduced to 145–150 nm with a PDI of 0.13–0.15. The prepared liposomes were loaded with the novel antiviral drug Triazavirin and used to determine the release profile. Triazavirin was included into liposome layer as a salt with biocompatible choline derivatives of limiting fatty acids. The appropriate lipid composition was used for the preparation of a larger quantity of liposomes coated by modified chitosan. It was shown that an appropriate combination of liposomes and polysaccharide layer potentially extended colloidal stability by up to 3 months and exhibited broad functional capabilities for surface modification.

New chitosan-coated liposomes for controlled release of active substances in HepG2 cells: Synthesis, biological characterization, cell viability and anti-inflammatory studies

New chitosan-coated liposomes for controlled release of active substances in HepG2 cells: Synthesis, biological characterization, cell viability and anti-inflammatory studies

In vitro release of grape-seed polyphenols encapsulated from uncoated and chitosan-coated liposomes

Grape-seed extract (GSE), a rich source for polyphenols, was incorporated into liposomes (1.1% w/w soy lecithin) using high-pressure homogenization (22,500psi). A chitosan coating (1% w/w) was used to obtain more stable liposomes. Physiochemical properties (ζ-potential, mean particle size) of all liposomes were analyzed. In vitro release of GSE-polyphenols from various liposomes was investigated by measuring the total phenolic content of the dialysate (acetate buffer, pH3.8±0.1, 25mM) over time. Diverse kinetic models were used to describe the release of the polyphenols incorporated from liposomes. Z-average particle diameters increased with the incorporation of GSE and chitosan coating. Chitosan-coated liposomes containing GSE had larger particle sizes than coated liposomes without GSE. The ζ-potential changed from −38mV in uncoated liposomes to +65mV in coated liposomes. Entrapment efficiency for uncoated and coated liposomes was 88.2±4.7% and 99.5±2.3%, respectively. The release rate increased gradually by increasing time. In vitro release of GSE polyphenols from both uncoated and coated liposomes followed an exponential equation (first order Q(t)=a·(1−exp(−k·t))). The release from coated liposomes was much lower than uncoated liposomes. The release rate after 24h from uncoated liposomes was 0.55 and from coated liposomes was 0.24. This study indicates that the release of bioactive compounds from liposomes can be reduced by coating with chitosan, allowing an application of coated liposomes with a controlled release of GSE polyphenols in water-based foods.

Fortification of dark chocolate with spray dried black mulberry (Morus nigra) waste extract encapsulated in chitosan-coated liposomes and bioaccessability studies

Fine-disperse anionic liposomes containing black mulberry (Morus nigra) extract (BME) were prepared by high pressure homogenization at 25,000psi. Primary liposomes were coated with cationic chitosan (0.4, w/v%) using the layer-by-layer depositing method and mixed with maltodextrin (MD) (20, w/v%) prior to spray drying. After that, spray dried liposomal powders containing BME were added to chocolates with alkalization degrees (pH 4.5, 6, 7.5) at conching temperatures of 40°C, 60°C, and 80°C. The results showed that, compared to spray dried extract, chitosan coated liposomal powders provided better protection of anthocyanin content in both increased temperature and pH. In addition, encapsulation in liposomes enhanced in vitro bioaccessability of anthocyanins. Chocolate was fortified with encapsulated anthocyanins maximum 76.8% depending on conching temperature and pH.

Environmental Stress and in Vitro Digestion Stability of Chitosan-Coated Liposomes

Environmental Stress and in Vitro Digestion Stability of Chitosan-Coated Liposomes

A chitosan-coated liposome encapsulating antibacterial peptide, Apep10: characterisation, triggered-release effects and antilisterial activity in thaw water of frozen chicken.

Contamination of Listeria monocytogenes in food and their processing environment is a focus of attention in the food industry. To achieve the controlled release of antibacterial agents to a food processing environment contaminated by L. monocytogenes, chitosan-stabilised liposomes encapsulating Apep10 (GLARCLAGTL), an antibacterial peptide derived from boiled-dried anchovies, were prepared by utilising listeria toxins to activate the peptide release. Characteristics including the particle size, polydispersity index (PDI), encapsulation efficiency (EE), and morphology of the chitosan-coated Apep10 liposomes were investigated. The chitosan liposomes were more stable than their uncoated counterparts, which indicated that the coating of chitosan on the surface of the liposomes inhibited undesirable vesicle fusion and payload release during storage. However, once the chitosan-stabilised liposomes encountered L. monocytogenes, which secretes pore-forming toxins, the encapsulated antibacterial peptide was released and it exerted antimicrobial effects on the strain. The results of time-kill inhibition, scanning electron microscopy (SEM), crystal violet staining and confocal laser scanning microscopy (CLSM) images demonstrated that these liposomes have favourable antibacterial and anti-biofilm activities against L. monocytogenes in the thaw water of frozen chicken. This bacterial toxin-enabled release of the encapsulated antibacterial peptide from chitosan-coated liposomes provides an effective approach for the control of listerial contamination. This technique can be broadly applied to treat contamination by a variety of pathogens that secrete pore-forming toxins.

An in vitro study of mucoadhesion and biocompatibility of polymer coated liposomes on HT29-MTX mucus-producing cells

Drug delivery to the oral cavity poses a significant challenge due to the short residence time of the formulations at the site of action. From this point of view, nanoparticulate drug delivery systems with ability to adhere to the oral mucosa are advantageous as they could increase the effectiveness of the therapy. Positively, negatively and neutrally charged liposomes were coated with four different types of polymers: alginate, low-ester pectin, chitosan and hydrophobically modified ethyl hydroxyethyl cellulose. The mucoadhesion was studied using a novel in vitro method allowing the liposomes to interact with a mucus-producing confluent HT29-MTX cell-line without applying any external force. MTT viability and paracellular permeability tests were conducted on the same cell-line. The alginate-coated liposomes achieved a high specific (genuine) mucin interaction, with a low potential of cell-irritation. The positively charged uncoated liposomes achieved the highest initial mucoadhesion, but also displayed a higher probability of cell-irritation. The chitosan-coated liposomes displayed the highest potential for long lasting mucoadhesion, but with the drawback of a higher general adhesion (tack) and a higher potential for irritating the cells.

Encapsulation of bioactive salmon protein hydrolysates with chitosan-coated liposomes

A nano-encapsulation strategy for a chitosan-coated liposomal oral delivery system using milk fat globule membrane (MFGM) phospholipids for the entrapment of antidiabetic peptides prepared from Atlantic salmon (Salmo salar) protein hydrolysates (SPH) was developed. The size, zeta potential, entrapment efficiency, stability during freeze-drying freeze thawing, and long-term storage abilities of the nano-capsules were investigated as a function of concentrations of phospholipid and chitosan coating material. Chitosan coating greatly improved the stability of liposomes. The maximum encapsulation efficiency (71.3%) and physical stability were achieved with 10% MFGM phospholipid and 0.4% chitosan. Chitosan coating significantly prolonged the release of SPH in simulated biological fluids. In conclusion, liposomes with “optimal” chitosan coating-concentration show great promise as a potential new delivery system for protein hydrolysates.

Resveratrol-loaded liposomes for topical treatment of the vaginal inflammation and infections

Resveratrol (RES), chemically known as 3,5,4′-trihydroxy-trans-stilbene, is a promising multi-targeted anti-oxidative and anti-inflammatory natural polyphenol. Preclinical studies showed its biological activities against the pathogens of sexually transmitted diseases causing vaginal inflammation and infections. Due to its low solubility and poor bioavailability, the optimal therapeutic uses are limited. Therefore, a clinically acceptable topical vaginal formulation of RES exhibiting optimal therapeutic effects is highly desirable. For this purpose, we prepared and optimized chitosan-coated liposomes with RES. The coated vesicles (mean diameter 200nm) entrapped up to 77% of RES, a sufficient load to assure required therapeutic outcome. In vitro drug release study showed the ability of liposomes to provide sustained release of RES. In vitro anti-oxidative activities of RES, namely DPPH and ABTS•+ radicals scavenging assays, confirmed RES to be as potent as standard anti-oxidants, vitamins C and E. The anti-oxidative activities of RES and its corresponding liposomal formulation were also compared by measuring enhanced superoxide dismutase (SOD) activities in lipopolysaccharide (LPS)-induced J774A.1 cells. In vitro anti-inflammatory activities were compared by measuring nitric oxide (NO), tumor necrosis factor (TNF)-α and interleukin (IL)-1β production in LPS-induced J774A.1 cells. Liposomal RES was found to exhibit stronger anti-oxidative and anti-inflammatory activities than RES solution.

Temperature-dependent structure stability and in vitro release of chitosan-coated curcumin liposome

Liposome, a promising delivery system with phospholipid bilayer, could improve the water solubility of curcumin, which is a polyphenolic natural product with many bioactivities. However, the instability of liposome limits its development in application. In this study, the chitosan was used to protect the structure stability of phospholipid bilayer of curcumin liposome and control the sustained release rate of curcumin further. The temperature stability and phase transition were studied by differential scanning calorimetry. When curcumin molecule was embedded in phospholipid bilayer, the pre-transition temperature (50.40°C) and main phase transition temperature (61.47°C) decreased about 10°C compared to it without curcumin, and phospholipid bilayer fluidity was increased. The pre-transition temperature was disappeared after chitosan coated on the surface of curcumin liposome. The thermal stability test and X-ray diffraction also indicate that high temperature could change the structure of liposome and chitosan could protect the curcumin from damage and leak. The in vitro release study showed that the cumulative release rate got faster with temperature increased and chitosan could decrease the release rate. These results may guide the potential application of chitosan-coated liposome as a carrier of curcumin in nutraceutical and functional foods.