Cross-linked chitosan/liposome hybrid system for the intestinal delivery of quercetin

Quercetin-Loaded Nanostructured Lipid Carrier In Situ Gel for Brain Targeting Through Intranasal Route: Formulation, In Vivo Pharmacokinetic and Pharmacodynamic Studies

Quercetin (QT) shows potential for protecting against neurodegenerative diseases like Alzheimer's. However, its limited bioavailability and instability in physiological pH hinder its clinical use. The purpose of this work is to construct QT-filled nanostructured lipid carriers (QT-NLC) intranasal in situ gel to enhance pharmacokinetic and pharmacodynamic performance. NLCs were developed using a melt emulsification-high-pressure homogenization and were optimized using design expert software with the Box-Behnken design. NLCs were then incorporated into an in situ gel based on Lutrol F127 and further characterized. The pharmacodynamics of the formulation was evaluated in neurodegeneration induced by trimethyl tin (TMT) Wistar rats. The optimized QT in situ gel had spherical shape, entrapment efficiency of 96.1 ± 4.40%, and in vitro drug release of 83.74 ± 1.40%. The mean particle size was 123.3 ± 5.46 nm. After intranasal administration, in vivo single-dose pharmacokinetic studies demonstrated a significant therapeutic concentration of drug in CNS, having Cmax 183.41 ± 11.76 ng/mL and Tmax of 2 h. The more brain targeting efficiency of NLCs was proved by the developed QT in situ gel, which had a higher drug targeting efficiency (DTE) of 117.47% and drug targeting potential (DTP) of 88.9%. As compared to the neurodegeneration control group, the QT in situ gel-treated group had significantly decreased escape latency and pathlength. Biochemical analysis and histological investigations demonstrated that QT in situ gel exhibited superior anti-Alzheimer's potential compared to standard drug, donepezil. The promising results of the developed and optimized intranasal QT in situ gel suggest its potential and can be used in Alzheimer's disease management.

Use of sodium alginate coatings to improve bioavailability of liposomes containing DPP-IV inhibitory collagen peptides

Sodium alginate (SA) was used to coat liposomes containing DPP-IV inhibitory collagen peptides to improve their stability and in vitro absorption for intra-oral delivery. The liposome structure as well as entrapment efficiency and DPP-IV inhibitory activity was characterized. The liposome stability was determined by measuring in vitro release rates and their gastrointestinal stability. Transcellular permeability of liposomes was further tested to characterize their permeability in small intestinal epithelial cells. The results showed that the 0.3% SA coating increased the diameter (166.7 nm to 249.9 nm), absolute value of zeta potential (30.2 mV to 40.1 mV) and entrapment efficiency (61.52% to 70.99%) of liposomes. The SA-coated liposomes containing collagen peptides showed enhanced storage stability within one month, gastrointestinal stability increased by 50% in bioavailability, transcellular permeability increased by 18% in transmission percentage, and in vitro release rates reduced by 34%, compared to uncoated liposomes. SA coating liposomes are promising carriers for transporting hydrophilic molecules, may be beneficial for improving nutrient absorption and can protect bioactive compounds from being inactivated in the gastrointestinal tract.

Chitosan-Based Nano Systems for Natural Antioxidants in Breast Cancer Therapy

Breast cancer is a major cause of death globally, accounting for around 13% of all deaths. Chemotherapy, the common treatment for cancer, can have side effects that lead to the production of reactive oxygen species (ROS) and an increase in oxidative stress in the body. Antioxidants are important for maintaining the health of cells and helping the immune system function properly. They play a crucial role in balancing the body's internal environment. Using natural antioxidants is an alternative to mitigate the harmful effects of oxidative stress. However, around 80% of natural antioxidants have limited effectiveness when taken orally because they do not dissolve well in water or other solvents. This poor solubility affects their ability to be absorbed by the body and limits their bioavailability. One strategy that has been considered is to increase their water solubility to increase their oral bioavailability. Chitosan-based nanoparticle (CSNP) systems have been extensively explored due to their reliability and simpler synthesis routes. This review focuses on the various methods of chitosan-based nanoformulation for developing effective oral dosage forms for natural antioxidants based on the pharmacokinetics and pharmacodynamics properties. Chitosan (CS) could be a model, because of its wide use in polymeric NPs research, thus providing a better understanding of the role of vehicles that carry natural antioxidants in maintaining the stability and enhancing the performance of cancer drugs.

Effects of N-succinyl-chitosan coating on properties of astaxanthin-loaded PEG-liposomes: Environmental stability, antioxidant/antibacterial activities, and in vitro release

Astaxanthin (AST) has outstanding antioxidant and anti-inflammation bioactivities, but the low biocompatibility and stability limit its application in foods. In this study, N-succinyl-chitosan (NSC)-coated AST polyethylene glycol (PEG)-liposomes were constructed to enhance the biocompatibility, stability, and intestinal-targeted migration of AST. The AST NSC/PEG-liposomes were uniform in size, had larger particles, greater encapsulation efficiency, and better storage, pH, and temperature stability than the AST PEG-liposomes. AST NSC/PEG-liposomes exerted stronger antibacterial and antioxidant activities against Escherichia coli and Staphylococcus aureus than AST PEG-liposomes. The NSC coating not only protects AST PEG-liposomes from gastric acid but also prolongs the retention and sustained release of AST NSC/PEG-liposomes depending on the intestinal pH. Moreover, caco-2 cellular uptake studies showed that AST NSC/PEG-liposomes had higher cellular uptake efficiency than AST PEG-liposomes. And AST NSC/PEG-liposomes were taken up by caco-2 cells through clathrin mediated endocytic, macrophage pathways and paracellular transport pathway. These results further proved that AST NSC/PEG-liposomes delayed the release and promoted the intestinal absorption of AST. Hence, AST PEG-liposomes coated with NSC could potentially be used as an efficient delivery system for therapeutic AST.

Influence of different anionic polysaccharide coating on the properties and delivery performance of nanoliposomes for quercetin

Nanoliposome is an effective delivery system for polyphenols, whereas it always suffers from low electrostatic stability and oxidation of lipid membranes. Here, different charged anionic polysaccharides including carrageenan (-62.67 ± 1.85 mV), trehalose (-20.73 ± 1.42 mV), and pectin (-4.47 ± 0.38 mV) were used as coating material to improve the stability of nanoliposomes. Results showed that carrageenan coating greatly inhibited aggregation and fusion of nanoliposome. The coating of the higher charged polysaccharides produced the more hydrogen bonds and made the inner chains of lipid molecules more compact, thus improving the rigidity of the membrane and thermal stability. In addition, the polysaccharide coating effectively reduced the lateral diffusion within the membrane and the propagation rate of oxidation reaction. The aim of this study is to investigate the effect of anionic polysaccharides with different charges on coated nanoliposomes, provide reference for the delivery of quercetin.

Chitosan-Coated Niosomes Loaded with Ellagic Acid Present Antiaging Activity in a Skin Cell Line

The polyphenol compound ellagic acid (EA) extracted from pomegranate has potential bioactivity against different types of chronic diseases. Skin aging is a long-term physiological process caused by many environmental factors, the most important of which is exposure to sun ultraviolet (UV) radiation. UV-induced chronic photodamage of the skin results in extrinsic aging. This study aimed to evaluate the photoprotective effects of EA on the human fibroblast skin cell line HFB4 and investigate its capacity to protect collagen from UV-induced deterioration. EA was encapsulated into chitosan-coated niosomes to reduce the skin aging effect of UV radiation in vitro. The tested formulations (niosomes loaded with EA and chitosan-coated niosomes loaded with EA) were characterized using transmission electron microscopy, dynamic light scattering, and scanning electron microscopy. Furthermore, the in vitro release of EA was determined. The HFB4 cell line samples were split into five groups: control, UV, UV-EA, UV-NIO-EA, and UV-CS-NIO-EA. UV irradiation was applied to the cell line groups via a UV-emitting lamp for 1 h, and then cell viability was measured for each group. The expression of genes implicated in skin aging (Co1A1, TERT, Timp3, and MMP3) was also assessed to quantify the impact of the loaded EA. The findings showed that EA-loaded chitosan-coated niosomes improved cell survival, upregulated Col1A1, TERT, and Timp3 genes, and downregulated MMP3. Thus, nanoparticles encapsulating EA are potent antioxidants that can preserve collagen levels and slow down the aging process in human skin.

Synthesized nanoliposome-encapsulated kaempferol attenuates liver health parameters and gene expression in mice challenged by cadmium-induced toxicity

In the present research, we encapsulated a flavonoid called kaempferol into nanoliposomal structures and the health-promoting effects of synthesized nanoliposome-loaded kaempferol (NLK) were evaluated in mice challenged by cadmium-induced . The NLK characteristics, such as size, zeta potential, and polydispersity index, were 218.4 nm, -28.55 mV, and 0.29, respectively. The in vivo experiment revealed that the mice receiving water containing cadmium (2 mg/kg body weight/day) showed significant (p < 0.05) weight loss, an increase in liver enzyme activities, and hepatic oxidative stress. Dietary supplementation with NLK at concentrations of 2.5 and 5 mg/kg mice body weight notably (p < 0.05) improved the body weight, liver enzyme activities, hepatic oxidative stress, and antioxidant potential of the liver. Our findings elucidated that NLK could alleviate the toxicity of cadmium in mice challenged by cadmium-induced toxicity.

TPP-chitosomes as potential encapsulation system to protect carotenoid-rich extract obtained from carrot by-product: A comparison with liposomes and chitosomes

The objectives of this study were to extract bioactive compounds from carrot by-products and evaluate their chemical stability after encapsulation in liposomes (L) coated either with chitosan (Ch) or using sodium tripolyphosphate for chitosan complexation (TPP-Ch). The main compounds quantified in this study were carotenoids and total phenolic compounds, which reached encapsulation efficiencies higher than 75%. The TPP-Ch charged with carrot extract showed greater particle size (90.5 nm) and zeta potential (+22 mV) than vesicles without coating (68.0 nm and -2 mV, respectively), indicating that liposomes were successfully coated with chitosan. Regarding results of the carotenoid's encapsulated stability, TPP-Ch particles were more efficient preventing their degradation in all the experimental conditions studied (40 and 70 °C). It is significant that loaded TPP-Ch particles demonstrated similar results for the stability of carotenoid-rich extracts in ethanol, which would therefore be suitable for application in food industry or any aqueous matrices.

Advances on nanoformulation approaches for delivering plant-derived antioxidants: A case of quercetin

Oxidative stress has been implicated in tumorigenic, cardiovascular, neuro-, and age-related degenerative changes. Antioxidants minimize the oxidative damage through neutralization of reactive oxygen species (ROS) and other causative agents. Ever since the emergence of COVID-19, plant-derived antioxidants have received enormous attention, particularly in the Indian subcontinent. Quercetin (QCT), a bio-flavonoid, exists in the glycosylated form in fruits, berries and vegetables. The antioxidant potential of QCT analogs relates to the number of free hydroxyl groups in their structure. Despite presence of these groups, QCT exhibits substantial hydrophobicity. Formulation scientists have tested nanotechnology-based approaches for its improved solubilization and delivery to the intended site of action. By the virtue of its hydrophobicity, QCT gets encapsulated in nanocarriers carrying hydrophobic domains. Apart from passive accumulation, active uptake of such formulations into the target cells can be facilitated through well-studied functionalization strategies. In this review, we have discussed the approaches of improving solubilization and bioavailability of QCT with the use of nanoformulations.

Flavonoids: Food associations, therapeutic mechanisms, metabolism and nanoformulations

Flavonoids possess an impressive therapeutic potential, thereby imparting them a nutraceutical character. As it becomes increasingly common to consume foods associated with healing properties, it is imperative to understand the associations of different foods with different classes of nutraceutic compounds, and their mechanisms of therapeutic action. At the same time, it is important to address the limitations thereof so that plausible future directions may be drawn. This review summarizes the food associations of flavonoids, and discusses the mechanisms responsible for imparting them their nutraceutic properties, detailing the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway, inhibition of inflammatory signaling pathways such as toll-like receptor (TLR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), cyclooxygenase 2 (COX-2) and lipoxygenase-2 (LOX-2) mediators. Further on, the review explains the mechanism of flavonoids metabolism, reasons for low bioavailability and thereafter recapitulates the role of technological interventions to overcome the limitations, with a particular focus on nanoformulations that utilize the synergy between flavonoids and biocompatible materials used as nanocarriers, as reported in works spanning over a decade. It is the Generally Recognized as Safe (GRAS) classified carriers that will become the basis for developing functional formulations. It is promisingly noteworthy that some flavonoid formulations have been commercialized and mentioned therein. Such commercially viable and safe for consumption technological applications pave way for bringing science to the table, and add value to the innate properties of flavonoids.

Polymer-Modified Liposomes for Drug Delivery: From Fundamentals to Applications

Liposomes are highly advantageous platforms for drug delivery. To improve the colloidal stability and avoid rapid uptake by the mononuclear phagocytic system of conventional liposomes while controlling the release of encapsulated agents, modification of liposomes with well-designed polymers to modulate the physiological, particularly the interfacial properties of the drug carriers, has been intensively investigated. Briefly, polymers are incorporated into liposomes mainly using “grafting” or “coating”, defined according to the configuration of polymers at the surface. Polymer-modified liposomes preserve the advantages of liposomes as drug-delivery carriers and possess specific functionality from the polymers, such as long circulation, precise targeting, and stimulus-responsiveness, thereby resulting in improved pharmacokinetics, biodistribution, toxicity, and therapeutic efficacy. In this review, we summarize the progress in polymer-modified liposomes for drug delivery, focusing on the change in physiological properties of liposomes and factors influencing the overall therapeutic efficacy.

Tempranillo Grape Extract in Transfersomes: A Nanoproduct with Antioxidant Activity

Polyphenols are gaining increasing interest due to their beneficial properties to human health. Grape pomace, the by-product of wine production, is a source of these bioactive compounds. An extract from Tempranillo grape pomace was obtained and characterized qualitatively and quantitatively. The major components found were anthocyanins, flavan-3-ols, and flavonols. To improve the bioavailability of these compounds, the extract was formulated in phospholipid vesicles, namely transfersomes. Spherical unilamellar vesicles around 100 nm each were obtained. The antioxidant activity of both the extract and the transfersomes was evaluated by using colorimetric assays (i.e., DPPH, FRAP, and Folin–Ciocalteu). The cells’ viability and the antioxidant activity were assessed in keratinocytes. The results showed that the extract and the transfersomes had no cytotoxic effects and exerted remarkable antioxidant activity, which was more evident in a vesicle formulation. These findings highlighted the potential of the Tempranillo grape pomace extract and the efficacy of the incorporation into phospholipid vesicles.

Liposome-Polymer Complex for Drug Delivery System and Vaccine Stabilization

Liposomes have been used extensively as micro- and nanocarriers for hydrophobic or hydrophilic molecules. However, conventional liposomes are biodegradable and quickly eliminated, making it difficult to be used for delivery in specific routes, such as the oral and systemic routes. One way to overcome this problem is through complexation with polymers, which is referred to as a liposome complex. The use of polymers can increase the stability of liposome with regard to pH, chemicals, enzymes, and the immune system. In some cases, specific polymers can condition the properties of liposomes to be explicitly used in drug delivery, such as targeted delivery and controlled release. These properties are influenced by the type of polymer, crosslinker, interaction, and bond in the complexation process. Therefore, it is crucial to study and review these parameters for the development of more optimal forms and properties of the liposome complex. This article discusses the use of natural and synthetic polymers, ways of interaction between polymers and liposomes (on the surface, incorporation in lamellar chains, and within liposomes), types of bonds, evaluation standards, and their effects on the stability and pharmacokinetic profile of the liposome complex, drugs, and vaccines. This article concludes that both natural and synthetic polymers can be used in modifying the structure and physicochemical properties of liposomes to specify their use in targeted delivery, controlled release, and stabilizing drugs and vaccines.

Chitosan and its composites-based delivery systems: advances and applications in food science and nutrition sector

Natural bioactive ingredients have lower bioavailability because of their chemical instability and poor water solubility, which limits their applications in functional foods. Among diverse biopolymers that can be used to construct delivery systems of bioactives, chitosan has attracted extensive attention due to its unique cationic nature, excellent mucoadhesive properties and easy modification. In this review, chitosan and its composites-based food-grade delivery systems as well as the factors affecting their performance are summarized. Modification, crosslinking, combination with other biopolymer or utilization of coating material can effectively overcome the instability of pure chitosan-based carriers under acidic conditions, thereby constructing chitosan and its complex-based carriers with conspicuously improved performance. Furthermore, the applications of chitosan-based delivery systems in nutrition and health as well as their future development trends and challenges are discussed. Functional food ingredients, functional food packaging and biological health are potential applications of chitosan-based food-grade delivery systems. The research trends of nutraceutical delivery systems based on chitosan and its composites include co-delivery of nutrients and essential oils, targeted intestinal delivery, stimulus responsive/sustained release and their applications in real foods. In conclusion, food industry will be significantly promoted with the continuous innovation and development of chitosan-based nutraceutical delivery systems.

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.

Cubosomal lipid nanoassemblies with pH-sensitive shells created by biopolymer complexes: A synchrotron SAXS study

We report a strategy for sustainable development of pH-responsive cubic liquid crystalline nanoparticles (cubosomes), in which the structure-defining lyotropic nonlamellar lipid and the eventually encapsulated guest molecules can be protected by pH-sensitive polyelectrolyte shells with mucoadhesive properties. Bulk non-lamellar phases as well as pH-responsive polyelectrolyte-modified nanocarriers were formed by spontaneous assembly of the nonlamellar lipid monoolein and two biopolymers tailored in nanocomplexes with pH-dependent net charge. The mesophase particles involved positively charged N-arginine-modified chitosan (CHarg) and negatively charged alginate (ALG) chains assembled at different biopolymer concentrations and charge ratios into a series of pH-responsive complexes. The roles of Pluronic F127 as a dispersing agent and a stabilizer of the nanoscale dispersions were examined. Synchrotron small-angle X-ray scattering (SAXS) investigations were performed at several N-arginine-modified chitosan/alginate ratios (CHarg/ALG with 10, 15 and 20 wt% ALG relative to CHarg) and varying pH values mimicking the pH conditions of the gastrointestinal route. The structural parameters characterizing the inner cubic liquid crystalline organizations of the nanocarriers were determined as well as the particle sizes and stability on storage. The surface charge variations, influencing the measured zeta-potentials, evidenced the inclusion of the CHarg/ALG biopolymer complexes into the lipid nanoassemblies. The polyelectrolyte shells rendered the hybrid cubosome nanocarriers pH-sensitive and influenced the swelling of their lipid-phase core as revealed by the acquired SAXS patterns. The pH-responsiveness and the mucoadhesive features of the cubosomal lipid/polyelectrolyte nanocomplexes may be of interest for in vivo drug delivery applications.

Potential Applications of Chitosan-Based Nanomaterials to Surpass the Gastrointestinal Physiological Obstacles and Enhance the Intestinal Drug Absorption

The small intestine provides the major site for the absorption of numerous orally administered drugs. However, before reaching to the systemic circulation to exert beneficial pharmacological activities, the oral drug delivery is hindered by poor absorption/metabolic instability of the drugs in gastrointestinal (GI) tract and the presence of the mucus layer overlying intestinal epithelium. Therefore, a polymeric drug delivery system has emerged as a robust approach to enhance oral drug bioavailability and intestinal drug absorption. Chitosan, a cationic polymer derived from chitin, and its derivatives have received remarkable attention to serve as a promising drug carrier, chiefly owing to their versatile, biocompatible, biodegradable, and non-toxic properties. Several types of chitosan-based drug delivery systems have been developed, including chemical modification, conjugates, capsules, and hybrids. They have been shown to be effective in improving intestinal assimilation of several types of drugs, e.g., antidiabetic, anticancer, antimicrobial, and anti-inflammatory drugs. In this review, the physiological challenges affecting intestinal drug absorption and the effects of chitosan on those parameters impacting on oral bioavailability are summarized. More appreciably, types of chitosan-based nanomaterials enhancing intestinal drug absorption and their mechanisms, as well as potential applications in diabetes, cancers, infections, and inflammation, are highlighted. The future perspective of chitosan applications is also discussed.

Quercetin delivery characteristics of chitosan nanoparticles prepared with different molecular weight polyanion cross-linkers

The aim of the study was to investigate the effects of cross-linkers on quercetin (QUE) absorption characteristics of QUE-loaded chitosan nanoparticles (CS-NPs). CS-NPs (461.2-482.7 nm) were prepared by ionic gelation at pH 3.5 using tripolyphosphate (367.9 Da), dextran sulfate (>15 kDa), arabic gum (AG, >250 kDa), or hyaluronic acid (HA, >1000 kDa). Mucoadhesion and cell permeation of QUE were significantly increased by positive charged CS-NPs due to interactions with negatively charged mucosal layer. Moreover, CS-AG and CS-HA NPs prepared with relatively higher MW cross-linkers exhibited significantly higher adhesion and permeation than the others. These results were verified by a cellular antioxidant activity assay; CS-AG (137.5 unit) and CS-HA NPs (126.5 unit) showed significantly higher activities after internalization into Caco-2 cells. Therefore, encapsulation within CS-NPs prepared using high MW cross-linkers such as AG and HA is found to be potentially valuable techniques for improving the QUE absorption.

Design and optimization of quercetin-based functional foods

Quercetin is a flavonoid present in a wide variety of plant resources. Over the years, extensive efforts have been devoted to examining the potential biological effects of quercetin and to manipulating the chemical and physical properties of the flavonoid. However, limited studies have reviewed the opportunities and challenges of using quercetin in the development of functional foods. To address this necessity, in this review; we foremost present an overview of the chemical properties and stability of quercetin in food products followed by a detailed discussion of various strategies that enhance its oral bioavailability. We further highlight the areas to be practically considered during development of quercetin-based functional foods. By revisiting the current status of applied research on quercetin, it is anticipated that useful insights enabling research on quercetin can be potentially translated into practical applications in food product development.

Exploitation of Marine-Derived Robust Biological Molecules to Manage Inflammatory Bowel Disease

Naturally occurring biological entities with extractable and tunable structural and functional characteristics, along with therapeutic attributes, are of supreme interest for strengthening the twenty-first-century biomedical settings. Irrespective of ongoing technological and clinical advancement, traditional medicinal practices to address and manage inflammatory bowel disease (IBD) are inefficient and the effect of the administered therapeutic cues is limited. The reasonable immune response or invasion should also be circumvented for successful clinical translation of engineered cues as highly efficient and robust bioactive entities. In this context, research is underway worldwide, and researchers have redirected or regained their interests in valorizing the naturally occurring biological entities/resources, for example, algal biome so-called "treasure of untouched or underexploited sources". Algal biome from the marine environment is an immense source of excellence that has also been demonstrated as a source of bioactive compounds with unique chemical, structural, and functional features. Moreover, the molecular modeling and synthesis of new drugs based on marine-derived therapeutic and biological cues can show greater efficacy and specificity for the therapeutics. Herein, an effort has been made to cover the existing literature gap on the exploitation of naturally occurring biological entities/resources to address and efficiently manage IBD. Following a brief background study, a focus was given to design characteristics, performance evaluation of engineered cues, and point-of-care IBD therapeutics of diverse bioactive compounds from the algal biome. Noteworthy potentialities of marine-derived biologically active compounds have also been spotlighted to underlying the impact role of bio-active elements with the related pathways. The current review is also focused on the applied standpoint and clinical translation of marine-derived bioactive compounds. Furthermore, a detailed overview of clinical applications and future perspectives are also given in this review.

Recent Advancements in Polymer/Liposome Assembly for Drug Delivery: From Surface Modifications to Hybrid Vesicles

Liposomes are consolidated and attractive biomimetic nanocarriers widely used in the field of drug delivery. The structural versatility of liposomes has been exploited for the development of various carriers for the topical or systemic delivery of drugs and bioactive molecules, with the possibility of increasing their bioavailability and stability, and modulating and directing their release, while limiting the side effects at the same time. Nevertheless, first-generation vesicles suffer from some limitations including physical instability, short in vivo circulation lifetime, reduced payload, uncontrolled release properties, and low targeting abilities. Therefore, liposome preparation technology soon took advantage of the possibility of improving vesicle performance using both natural and synthetic polymers. Polymers can easily be synthesized in a controlled manner over a wide range of molecular weights and in a low dispersity range. Their properties are widely tunable and therefore allow the low chemical versatility typical of lipids to be overcome. Moreover, depending on their structure, polymers can be used to create a simple covering on the liposome surface or to intercalate in the phospholipid bilayer to give rise to real hybrid structures. This review illustrates the main strategies implemented in the field of polymer/liposome assembly for drug delivery, with a look at the most recent publications without neglecting basic concepts for a simple and complete understanding by the reader.

Current methodologies to refine bioavailability, delivery, and therapeutic efficacy of plant flavonoids in cancer treatment

Over the last two decades, several advancements have been made to improve the therapeutic efficacy of plant flavonoids, especially in cancer treatment. Factors such as low bioavailability, poor flavonoid stability and solubility, ineffective targeted delivery, and chemo-resistance hinder the application of flavonoids in anti-cancer therapy. Many anti-cancer compounds failed in the clinical trials because of unexpected altered clearance of flavonoids, poor absorption after administration, low efficacy, and/or adverse effects. Hence, the current research strategies are focused on improving the therapeutic efficacy of plant flavonoids, especially by enhancing their bioavailability through combination therapy, engineering gut microbiota, regulating flavonoids interaction with adenosine triphosphate binding cassette efflux transporters, and efficient delivery using nanocrystal and encapsulation technologies. This review aims to discuss different methodologies with examples from reported dietary flavonoids that showed an enhanced anti-cancer efficacy in both in vitro and in vivo models. Further, the review discusses the recent progress in biochemical modifications of flavonoids to improve bioavailability, solubility, and therapeutic efficacy.

Anti-rheumatic effect of quercetin and recent developments in nano formulation

Quercetin is a potential anti-rheumatoid drug. Nano formulation strategies could improve its solubility and efficacy.

Comparison of Polysaccharides as Coatings for Quercetin-Loaded Liposomes (QLL) and Their Effect as Antioxidants on Radical Scavenging Activity

Liposomes are microstructures containing lipid and aqueous phases employed in the encapsulation and delivery of bioactive agents. Quercetin-loaded liposomes (QLLs) were coated with three different polysaccharides and then tested as radical scavengers. Lactose (LCQLL), chitosan (CCQLL), and inulin (ICQLL) were employed as coating materials. Particle size determined by light scattering, showed primary size of 200 nm for all samples, while a secondary particle size of 600 nm was observed for CCQLL. Scanning electron microscopy (SEM) evidenced particle aggregation with the addition of the polysaccharide coating. Transmission electron microscopy (TEM) revealed the layered microstructure of liposomes composed of at least two layers, and primary particle size below 100 nm. QLL showed higher antioxidant activity than the coated liposomes. This behavior was attributed to the chemical interaction between quercetin and the corresponding coating polysaccharide in the layered structure, which traps the quercetin and keeps it unavailable for radical scavenging. From the three polysaccharides, lactose showed a better performance as coating material in the antioxidant activity, which suggested that the smaller size of the disaccharide molecule resulted in a faster releasing of the quercetin in the solution. Thus, LCQLL is an advantageous way to deliver quercetin for antioxidant purposes, where the low stability in delivered media of quercetin loaded liposomes is commonly compromised.

Chitosan-coated liposome-containing carbamazepine and coenzyme Q10: design, optimization and evaluation

Conventional formulations cannot sufficiently control seizures and influence on cognitive corruption and oxidative stress with chronic usage in patients with epilepsy. To defeat this issue, it was planned to develop polymeric liposome formulations that are using for their bioavailability and enhancer impact in oral epilepsy treatment. In this study, chitosan-coated liposomal formulations that encapsulate carbamazepine (CBZ) and coenzyme Q10 (CoQ10) were prepared and optimized by utilizing response surface methodology (RSM). Encapsulation efficiencies of CBZ and CoQ10, which were chosen as dependent variables for optimized chitosan-coated liposomal formulations were determined as 76.13%±2.34% and 82.36%±3.15%, respectively. Narrow size distribution was provided with an average size of 187.1 ± 2.35 nm, while a spherical and uniform shape was approved with transmission electron microscopy analyses. Cumulative release of 78.23% for CBZ and 27.12% for CoQ10 was obtained after 24 hours of in-vitro release study in sink conditions. Physical stability analyses demonstrated that optimum liposomes were convenient for storage at 5 ± 3 °C for at least 90 days. As a result, optimum chitosan-coated liposome containing CBZ and CoQ10 formulations could be suggested as a hopeful approach concerning their release, particle size, high encapsulation efficiency and stability for the treatment of epilepsy.

Synthesized chrysin-loaded nanoliposomes improves cadmium-induced toxicity in mice

In this study, chrysin as a natural flavonoid was encapsulated in nanoliposomal structures, and the synthesized nanoliposome-loaded chrysin (NLC) was further characterized for its physical properties and cytoprotective effects in mice that received cadmium-containing water. The results showed that the synthesized NLC is possessed spherical structure with the size of 185.1 nm and negative surface charge of - 26 mV with a poly dispersity index of 0.26. The mice received cadmium (2 mg/kg body weight/day) through drinking water showed weight loss and decease in the feed intake significantly (p ≤ 0.05). The cadmium notably (p ≤ 0.05) increased the liver enzymes including aspartate aminotransferase, alanine transaminase, and alkaline phosphatase; altered the liver metal deposition (cadmium, copper, manganese, selenium, and zinc); and induced hepatic oxidative stress (inducible nitric oxide synthase, catalase, superoxide dismutase, and glutathione peroxidase genes) with no remarkable histopathological changes. Furthermore, the cadmium impaired the morphology of jejunum through reducing villus height and villus width and increasing the crypt depth. Providing NLC as a dietary supplement at the concentrations of 2.5 and 5 mg/kg mice body weight significantly (p ≤ 0.05) improved the feed intake and body weight gain, modulated the liver enzymes, and alleviated the hepatic oxidative stress. The NLC also improved the antioxidant mineral deposition in the liver and morphohistological structure of jejunum. Consequently, the NLC is suggested as a potential dietary supplement to alleviate the symptoms of cadmium-induced toxicity in mice.

Stability and release performance of curcumin-loaded liposomes with varying content of hydrogenated phospholipids

The aim of this study was to substitute part of soybean phospholipid (SPC) with hydrogenated soybean phospholipid (HSPC) in curcumin-loaded liposomes (Cur-LP), in order to further enhance stability and release performances of curcumin. When the SPC/HSPC mass ratio changed from 10:0 to 5:5, vesicle size, encapsulation efficiency and alkali resistance of curcumin increased, although a small decrease in centrifugal stability was observed. Salt stability became worse as more HSPC was used (3:7 and 0:10). Owing storage at 4 °C and 25 °C, Cur-LP at a SPC/HSPC mass ratio of 5:5 performed well considering vesicle size, lipid oxidation and curcumin retention. These vesicles displayed also the best sustained-release performance in simulated digestion, attributed to the tighter lipid packing in membranes as indicated by fluorescence probes, DSC and FTIR. This study can guide the development of a Cur-LP product with improved shelf-life stability by using HSPC.

Quercetin Loaded Nanoparticles in Targeting Cancer: Recent Development

The spread of metastatic cancer cell is the main cause of death worldwide. Cellular and molecular basis of the action of phytochemicals in the modulation of metastatic cancer highlights the importance of fruits and vegetables. Quercetin is a natural bioflavonoid present in fruits, vegetables, seeds, berries, and tea. The cancer-preventive activity of quercetin is well documented due to its anti-inflammatory, anti-proliferative and anti-angiogenic activities. However, poor water solubility and delivery, chemical instability, short half-life, and low-bioavailability of quercetin limit its clinical application in cancer chemoprevention. A better understanding of the molecular mechanism of controlled and regulated drug delivery is essential for the development of novel and effective therapies. To overcome the limitations of accessibility by quercetin, it can be delivered as nanoconjugated quercetin. Nanoconjugated quercetin has attracted much attention due to its controlled drug release, long retention in tumor, enhanced anticancer potential, and promising clinical application. The pharmacological effect of quercetin conjugated nanoparticles typically depends on drug carriers used such as liposomes, silver nanoparticles, silica nanoparticles, PLGA (Poly lactic-co-glycolic acid), PLA (poly(D,L-lactic acid)) nanoparticles, polymeric micelles, chitosan nanoparticles, etc. In this review, we described various delivery systems of nanoconjugated quercetin like liposomes, silver nanoparticles, PLGA (Poly lactic-co-glycolic acid), and polymeric micelles including DOX conjugated micelles, metal conjugated micelles, nucleic acid conjugated micelles, and antibody-conjugated micelles on in vitro and in vivo tumor models; as well as validated their potential as promising onco-therapeutic agents in light of recent updates.

Ocular Formulation Based on Palmitoylethanolamide-Loaded Nanostructured Lipid Carriers: Technological and Pharmacological Profile

The present work was aimed for the preparation of a stable nanostructured lipid carrier (NLC) system for the delivery of N-palmitoylethanolamide (PEA) to the back of the eye. PEA is an interesting natural compound showing anti-inflammatory and neuroprotective activities. The limits of PEA (poor solubility and high instability) justify its nanoencapsulation into drug delivery systems. Two different well-known techniques were compared to formulate NLC: the high shear homogenization technique (HSH) and the method based on a combination of HSH technique and ultrasonication (HSH/US). Nanoparticles were evaluated in relation to mean size, homogeneity, surface charge, and physical stability by Turbiscan technology. Retinal distribution of PEA was carried out in a rat eye after single instillation of PEA-NLC ophthalmic formulation. The novel formulation delivered remarkable levels of PEA to the retina. Lastly, topical administration of PEA-NLC ophthalmic formulation was able to significantly inhibits retinal tumor necrosis factor-α (TNF-α) levels in streptozotocin-induced diabetic rats. The present findings suggest that the novel ophthalmic formulation may be useful for the treatment of retinal diseases such as diabetic retinopathy. Clinical studies are in progress to evaluate this possibility.

Enhancing the potential preclinical and clinical benefits of quercetin through novel drug delivery systems

Quercetin is reported to have numerous pharmacological actions, including antidiabetic, anti-inflammatory and anticancer activities. The main mechanism responsible for its pharmacological activities is its ability to quench reactive oxygen species (ROS) and, hence, decrease the oxidative stress responsible for the development of various diseases. Despite its proven therapeutic potential, the clinical use of quercetin remains limited because of its low aqueous solubility, bioavailability, and substantial first-pass metabolism. To overcome this, several novel formulations have been reported. In this review, we focus on the applications of quercetin extract as well as its novel formulations for treating different disorders. We also examine its proposed mechanism of action of quercetin.