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

Preparation, modification, characterization, and stability evaluation of 5-methyltetrahydrofolate liposomes

As an essential B vitamin, folate participates in one‑carbon metabolism. The 5-methyltetrahydrofolate (5-MTHF) avoids the drawbacks associated with folic acid and native folylpolyglutamate folate in food, thereby emerging as a superior alternative to folate supplement. To enhance the stability and digestibility of 5-MTHF, nanoliposome (NL) was modified using a layer-by-layer self-assembly method with chitosan (CH) and pectin (P). Chitosan-nanoliposome (CH-NL) and pectin-chitosan-nanoliposome (P-CH-NL) were created, each featuring a core-shell structure. P-CH-NL achieved an encapsulation efficiency of 64.62 %, loading efficiency of 1.05 mg/g, and particle size of 285.86 nm. It exhibited better physical stability and 5-MTHF retention (>80 %) under various conditions, including salt and pH variations, as well as oxidative, thermal, fermentation, and UV stress. During in vitro digestion, P-CH-NL protected 5-MTHF until it was released into the small intestine. This study highlighted the application prospects of multilayer liposome-loaded 5-MTHF as a stable, highly digestible folate supplement.

Chitosan as a Plurivalent Biopolymer in Nanodelivery Systems

(1) Background: This review study will delve into the potential of chitosan nanoparticles (NPs) as adaptable carriers for targeted drug delivery in different therapeutic areas. Chitosan is a biopolymer derived from chitin that has attracted interest in drug delivery applications because of its high biocompatibility and biodegradability. (2) Methods: A comprehensive literature review was conducted by following a careful systematized protocol for searching databases like PubMed, Google Scholar and ScienceDirect. (3) Results: Chitosan NPs are good drug delivery vehicles, notably for cancer. Studies reveal that doxorubicin-loaded chitosan NPs dramatically enhance toxicity to tumor cells compared to free medicines, yielding tumor suppression rates of up to 60%. Researchers found that chemotherapeutics had an 85% encapsulation efficiency (EE), lowering systemic toxicity. Magnetic and pH-responsive chitosan NPs boost drug accumulation by 63% and apoptosis by 54%. Chitosan also boosts medication retention in the lungs by 2.3×, per pulmonary delivery trials. Chitosan NPs also boost ocular medication bioavailability by 3× and improve nasal absorption by 30%, crossing the blood-brain barrier. For bone regeneration, chitosan scaffolds enhance bone mineral density by 46%, facilitating osteogenesis and healing. (4) Conclusions: NPs made of chitosan provide a solid foundation for improving drug delivery systems; yet there are still issues with material variability, scalability, and meeting regulatory requirements that need fixing. Research into combination treatments, ways to increase their specificity, and ways to optimize these NPs offers promising prospects for the creation of novel therapeutic approaches with the potential to improve patient outcomes.

Chitosan-Based Nanoformulations: Preclinical Investigations, Theranostic Advancements, and Clinical Trial Prospects for Targeting Diverse Pathologies

Chitosan, a biocompatible and biodegradable polymer, has attracted significant interest in the development of nanoformulations for targeted drug delivery and therapeutic applications. The versatility of chitosan lies in its modifiable functional groups, which can be tailored to diverse applications. Nanoparticles derived from chitosan and its derivatives typically exhibit a positive surface charge and mucoadhesive properties, enabling them to adhere to negatively charged biological membranes and gradually release therapeutic agents. This comprehensive review investigates the manifold roles of chitosan-based nanocarriers, ranging from preclinical research to theranostic applications and clinical trials, across a spectrum of diseases, including neurological disorders, cardiovascular diseases, cancer, wound healing, gastrointestinal disorders, and pulmonary diseases. The exploration starts with an overview of preclinical studies, emphasizing the potential of chitosan-based nanoformulations in optimizing drug delivery, improving therapeutic outcomes, and mitigating adverse effects in various disease categories. Advancements in theranostic applications of chitosan-based nanoformulations highlight their adaptability to diverse diseases. As these nanoformulations progress toward clinical translation, this review also addresses the regulatory challenges associated with their development and proposes potential solutions.

Oleanolic acid derivative self-assembled aggregates based on heparin and chitosan for breast cancer therapy

Oleanolic acid is an active ingredient from natural products with anti-breast cancer activity. However, the poor solubility in water and low bioavailability have limited its effectiveness in clinic. To improve the anticancer activity of oleanolic acid, we synthesized a novel oleanolic quaternary ammonium (QDT), which, driven by electrostatic interactions, was introduced into heparin and coated with chitosan to obtain a QDT/heparin/chitosan nanoaggregate (QDT/HEP/CS NAs). QDT/HEP/CS NAs showed the negative zeta potential (-35.01 ± 4.38 mV), suitable mean particle size (150.45 ± 0.68 nm) with strip shape, and high drug loading (36 %). The coated chitosan had strong anti-leakage characteristics toward QDT under physiological conditions. More importantly, upon sustained release in tumor cells, QDT could significantly decrease the mitochondrial membrane potential and induce apoptosis of breast cancer cells. Further in vivo antitumor study on 4 T1 tumor-bearing mice confirmed the enhanced anticancer efficacy of QDT/HEP/CS NAs via upregulation of caspase-3, caspase-9 and cytochrome C, which was attributed to the high accumulation in tumor via the enhanced permeability and retention effect. Moreover, QDT/HEP/CS NAs significantly enhanced the biosafety and biocompatibility of QDT in vitro and in vivo. Collectively, the development of QDT/HEP/CS NAs with high antitumor activity, favorable biodistribution and good biocompatibility provided a safe, facile and promising strategy to improve the anti-cancer effect of traditional Chinese medicine ingredients.

Orally Deliverable Microalgal-Based Carrier with Selenium Nanozymes for Alleviation of Inflammatory Bowel Disease

Excessive reactive oxygen species (ROS) is a hallmark of both the onset and progression of inflammatory bowel disease (IBD), where a continuous cycle of ROS and inflammation drives the progression of diseases. The design of oral antioxidant nanoenzymes for scavenging ROS has emerged as a promising strategy to intervene in IBD. However, the practical application of these nanoenzymes is limited due to their single catalytical property and significantly impacted by substantial leakage in the upper gastrointestinal tract. This study introduces a novel oral delivery system, SP@CS-SeNPs, combining natural microalgae Spirulina platensis (SP), which possesses superoxide dismutase (SOD)-like activity, with chitosan-functionalized selenium nanoparticles (CS-SeNPs) that exhibit catalase-like activity. The SP@CS-SeNPs system leverages the dual catalytic capabilities of these components to initiate a cascade reaction that first converts superoxide anion radicals (O2•-) into hydrogen peroxide (H2O2), and then catalyzes the decomposition of H2O2 into water and oxygen. This system not only utilizes the resistance of the microalgae carrier to gastric acid and its efficient capture by intestinal villi, thereby enhancing intestinal distribution and retention but also demonstrates significant anti-inflammatory effects and effective repair of the damaged intestinal barrier in a colitis mice model. These results demonstrate that this oral delivery system successfully combines the features of microalgae and nanozymes, exhibits excellent biocompatibility, and offers a novel approach for antioxidant nanozyme intervention in IBD.

Rutin-loaded chitosan nanoparticles alleviated Freund's adjuvant induced rheumatoid arthritis via modulating oxidative stress and inflammatory parameters in Wistar rats

Rheumatoid arthritis (RA) is the most common chronic inflammatory disease, primarily affecting the joints and with stromal tissue dysregulation causing chronic inflammation and joint destruction. Rutin is a natural flavonoid with potential therapeutic properties in chronic destructive conditions including rheumatoid diseases. In this study, the protective effects of rutin nanoformulation in an animal model of rheumatoid arthritis caused by Freund's complete adjuvant (FCA) were investigated. Sixty male rats were randomly divided into ten groups including normal, negative control, prednisolone 10 mg/kg (positive control), 3 doses of rutin (15, 30, 45mg/kg), rutin nanoparticles (15, 30, 45 mg/kg), and nanoparticle without rutin, for 28 days. Different behavioral parameters including the open field test, acetone drop test, hot plate test, Von Frey test, and inclined plane test were evaluated. Serum levels of glutathione (GSH), catalase, and nitric oxide as well as histopathological analyses were measured in different groups. Also, matrix metalloproteinase (MMP)-2 and MMP-9 activity were appraised by gelatin zymography. The injection of FCA prolonged the rats' immobility duration in comparison to the control group. Rheumatoid arthritis induction also increased nitric oxide and decreased GSH and catalase levels, while these effects were reversed in the groups that received nanoparticles containing rutin and prednisolone. Rutin nanoparticles suppressed MMP-9 and activated MMP-2. Also, this rutin drug delivery system plays a significant role in the improvement of histopathological symptoms. Considering the improvement of behavioral and tissue symptoms and the modulation of the level of inflammatory cytokines, nanoparticles containing rutin can be proposed as a suitable approach in the management of patients with rheumatoid arthritis.

Nanomaterials modulate tumor-associated macrophages for the treatment of digestive system tumors

The treatment of digestive system tumors presents challenges, particularly in immunotherapy, owing to the advanced immune tolerance of the digestive system. Nanomaterials have emerged as a promising approach for addressing these challenges. They provide targeted drug delivery, enhanced permeability, high bioavailability, and low toxicity. Additionally, nanomaterials target immunosuppressive cells and reshape the tumor immune microenvironment (TIME). Among the various cells in the TIME, tumor-associated macrophages (TAMs) are the most abundant and play a crucial role in tumor progression. Therefore, investigating the modulation of TAMs by nanomaterials for the treatment of digestive system tumors is of great significance. Here, we present a comprehensive review of the utilization of nanomaterials to modulate TAMs for the treatment of gastric cancer, colorectal cancer, hepatocellular carcinoma, and pancreatic cancer. We also investigated the underlying mechanisms by which nanomaterials modulate TAMs to treat tumors in the digestive system. Furthermore, this review summarizes the role of macrophage-derived nanomaterials in the treatment of digestive system tumors. Overall, this research offers valuable insights into the development of nanomaterials tailored for the treatment of digestive system tumors.

Effect of Tight Junction-Modulating FCIGRL-Modified Peptides on the Intestinal Absorption of Doxorubicin in Rats

Doxorubicin is a potent chemotherapy drug, but its oral bioavailability is limited due to its low membrane permeability. Thus, absorption enhancers such as zonula occludens toxin and its six-mer fragment, FCIGRL, have been studied to address this issue. This study aimed to evaluate the effectiveness of four peptides (Pep1, Pep2, Pep3, and Pep4) derived from FCIGRL and investigate the changes in the absorption of doxorubicin, to propose an absorption enhancer for doxorubicin. Pep1 is a modified version of FCIGRL in which the hydroxyl group at the C-terminus is replaced with an amino group. Pep2 is a modified Pep1 in which cysteine is replaced with N3-substituted dipropionic acid. Pep3 and Pep4 are Pep2-modified homodimers. Pharmacokinetic analysis was performed in rats after the intraduodenal administration of doxorubicin solutions containing each FCIGRL-modified peptide and the stabilizer levan or benzalkonium chloride (BC). The results showed that Pep3 and Pep4 administered with levan each significantly increased the intestinal absorption of doxorubicin, as did Pep2 administered with levan/BC. In particular, 10 mg·kg-1 of Pep4 with levan significantly increased the area under the curve (AUC)0-240min of doxorubicin by 2.38-fold (p < 0.01) and the peak concentration (Cmax) by 3.30-fold (p < 0.01) compared to the control solution. The study findings indicate that Pep2, Pep3, and primarily Pep4 are novel absorption enhancers that can open tight junctions for doxorubicin, and the effectiveness of the peptides was directly affected by the presence of levan or levan/BC.

In vivo investigation of the anti-liver fibrosis impact of Balanites aegyptiaca/ chitosan nanoparticles

Balanites aegyptiaca (B. aegyptiaca) is an African herb with traditional medical applications. Various pathogenic factors cause hepatic fibrosis and require novel treatment alternatives. Nanoformulation-based natural products can overcome the available drug problems by increasing the efficacy of natural products targeting disease markers. The current study investigated B. aegyptiaca methanolic extract using high-pressure liquid chromatography (HPLC), and B. aegyptiaca/chitosan nanoparticles were prepared. In vivo, evaluation tests were performed to assess the curative effect of the successfully prepared B. aegyptiaca/chitosan nanoparticles. For 30 days, the rats were divided into six groups, typical and fibrosis groups, where the liver fibrosis groups received B. aegyptiaca extract, silymarin, chitosan nanoparticles, and B. aegyptiaca/chitosan nanoparticles daily. In the current investigation, phenolic molecules are the major compounds detected in B. aegyptiaca extract. UV showed that the prepared B. aegyptiaca /chitosan nanoparticles had a single peak at 280 nm, a particle size of 35.0 ± 6.0 nm, and a negative charge at - 8.3 mV. The animal studies showed that the synthetic B. aegyptiaca/chitosan nanoparticles showed substantial anti-fibrotic protective effects against CCl4-induced hepatic fibrosis in rats when compared with other groups through optimization of biochemical and oxidative markers, improved histological changes, and modulated the expression of Col1a1, Acta2 and Cxcl9 genes, which manage liver fibrosis. In conclusion, the current research indicated that the prepared B. aegyptiaca/chitosan nanoparticles improved histological structure and significantly enhanced the biochemical and genetic markers of liver fibrosis in an animal model.

Recent advances in drug delivery systems based on natural and synthetic polymes for treating obesity

Obesity stands as a pervasive global public health issue, posing a formidable threat to human well-being as its prevalence continues to surge year by year. Presently, pharmacological treatment remains the favored adjunct strategy for addressing obesity. However, conventional delivery methods suffer from low bioavailability and the potential for side effects, underscoring the pressing need for more efficient and targeted delivery approaches. Recent research has delved extensively into emerging drug delivery systems employing polymers as carriers, with numerous preclinical studies contributing to the growing body of knowledge. This review concentrates on the utilization of natural polymers as drug delivery systems for the treatment of obesity, encompassing recent advancements in both natural and synthetic polymers. The comprehensive exploration includes an analysis of the advantages and disadvantages associated with these polymer carriers. The examination of these characteristics provides valuable insights into potential future developments in the field of drug delivery for obesity treatment.

Classification and design strategies of polysaccharide-based nano-nutrient delivery systems for enhanced bioactivity and targeted delivery: A review

Since many nutrients are highly sensitive, they cannot be absorbed and utilized efficiently by the body. Using nano-delivery systems to encapsulate nutrients is an effective method of solving the problems associated with the application of nutrients at this stage. Polysaccharides, as natural biomaterials, have a unique chemical structure, ideal biocompatibility, biodegradability and low immunogenicity. This makes polysaccharides powerful carriers that can enhance the biological activity of nutrients. However, the true role of polysaccharide-based delivery systems requires an in-depth understanding of the structural and physicochemical characteristics of polysaccharide-based nanodelivery systems, as well as effective modulation of the intestinal delivery mechanism and the latest advances in nano-encapsulation. This review provides an overview of polysaccharide-based nano-delivery systems dependent on different carrier types, emphasizing recent advances in the application of polysaccharides, a biocomposite material designed for nutrient delivery systems. Strategies for polysaccharide-based nano-delivery systems to enhance the bioavailability of orally administered nutrients from the perspective of the intestinal absorption barrier are presented. Characterization methods for polysaccharide-based nano-delivery systems are presented as well as an explanation of the formation mechanisms behind nano-delivery systems from the perspective of molecular forces. Finally, we discussed the challenges currently facing polysaccharide-based nano-delivery systems as well as possible future directions for the future.

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.

Oral Microalgae-Nano Integrated System against Radiation-Induced Injury

The increasing applications of ionizing radiation in society raise the risk of radiation-induced intestinal and whole-body injury. Astaxanthin is a powerful antioxidant to reduce the reactive oxygen generated from radiation and the subsequent damage. However, the oral administration of astaxanthin remains challenging owing to its low solubility and poor bioavailability. Herein, we facilely construct an orally used microalgae-nano integrated system (SP@ASXnano) against radiation-induced intestinal and whole-body injury, combining natural microalgae Spirulina platensis (SP) with astaxanthin nanoparticles (ASXnano). SP and ASXnano show complementation in drug delivery to improve distribution in the intestine and blood. SP displays limited gastric drug loss, prolonged intestinal retention, constant ASXnano release, and progressive degradation. ASXnano improves drug solubility, gastric stability, cell uptake, and intestinal absorption. SP and ASXnano have synergy in many aspects such as anti-inflammation, microbiota protection, and fecal short-chain fatty acid up-regulation. In addition, the system is ensured with biosafety for long-term administration. The system organically combines the properties of microalgae and nanoparticles, which was expected to expand the medical application of SP as a versatile drug delivery platform.

Surface engineering of chitosan nanosystems and the impact of functionalized groups on the permeability of model drug across intestinal tissue

Surface attributes of nanocarriers are crucial to determine their fate in the gastrointestinal (GI) tract. Herein, we have functionalized chitosan with biochemical moieties including rhamnolipid (RL), curcumin (Cur) and mannose (M). FTIR spectra of functionalized chitosan nanocarriers (FCNCs) demonstrated successful conjugation of M, Cur and RL. The functional moieties influenced the entrapment of model drug i.e., coumarin-6 (C6) in FCNCs with payload-hosting and non-leaching behavior i.e., >91 ± 2.5 % with negligible cumulative release of <2 % for 5 h in KREB, which was further verified in the simulated gastric and intestinal fluids. Consequently, substantial difference in the size and zeta potential was observed for FCNCs with different biochemical moieties. Scanning electron microscopy and atomic force microscopy of FCNCs displayed well-dispersed and spherical morphology. In addition, in vitro cytotoxicity results of FCNCs confirmed their hemocompatibility. In the ex-vivo rat intestinal models, FCNCs displayed a time-dependent-phenomenon in cellular-uptake and adherence. However, apparent-permeability-coefficient and flux values were in the order of C6-RL-FCNCs > C6-M-FCNCs > C6-Cur-FCNCs = C6-CNCs > Free-C6. Furthermore, the transepithelial electrical resistance revealed the FCNCs mediated recovery of membrane-integrity with reversible tight junctions opening. Thus, FCNCs have the potential to overcome the poor solubility and/or permeability issues of active pharmaceutical ingredients and transform the impact of functionalized-nanomedicines in the biomedical industry.

Oral Delivery of Therapeutic Antibodies with a Transmucosal Polymeric Carrier

Therapeutic proteins are playing increasingly important roles in treating numerous types of diseases. However, oral administration of proteins, especially large ones (e.g., antibodies), remains a great challenge due to their difficulties in penetrating intestinal barriers. Herein, fluorocarbon-modified chitosan (FCS) is developed for efficient oral delivery of different therapeutic proteins, in particular large ones such as immune checkpoint blockade antibodies. In our design, therapeutic proteins are mixed with FCS to form nanoparticles, lyophilized with appropriate excipients, and then filled into enteric capsules for oral administration. It has been found that FCS could promote transmucosal delivery of its cargo protein via inducing transitory rearrangement of tight junction associated proteins between intestinal epithelial cells and subsequently release free proteins into blood circulation. It is shown that at a 5-fold dose oral delivery of anti-programmed cell death protein-1 (αPD1) or its combination with anti-cytotoxic T-lymphocyte antigen 4 (αCTLA4) using this method could achieve comparable antitumor therapeutic responses to that achieved by intravenous injection of corresponding free antibodies in various types of tumor models and, more excitingly, result in significantly reduced immune-related adverse events. Our work successfully demonstrates the enhanced oral delivery of antibody drugs to achieve systemic therapeutic responses and may revolutionize the future clinical usage of protein therapeutics.

Development of Crosslinker-Free Polysaccharide-Lysozyme Microspheres for Treatment Enteric Infection

Antibiotic abuse in the conventional treatment of microbial infections, such as inflammatory bowel disease, induces cumulative toxicity and antimicrobial resistance which requires the development of new antibiotics or novel strategies for infection control. Crosslinker-free polysaccharide-lysozyme microspheres were constructed via an electrostatic layer-by-layer self-assembly technique by adjusting the assembly behaviors of carboxymethyl starch (CMS) on lysozyme and subsequently outer cationic chitosan (CS) deposition. The relative enzymatic activity and in vitro release profile of lysozyme under simulated gastric and intestinal fluids were investigated. The highest loading efficiency of the optimized CS/CMS-lysozyme micro-gels reached 84.9% by tailoring CMS/CS content. The mild particle preparation procedure retained relative activity of 107.4% compared with free lysozyme, and successfully enhanced the antibacterial activity against E. coli due to the superposition effect of CS and lysozyme. Additionally, the particle system showed no toxicity to human cells. In vitro digestibility testified that almost 70% was recorded in the simulated intestinal fluid within 6 h. Results demonstrated that the cross-linker-free CS/CMS-lysozyme microspheres could be a promising antibacterial additive for enteric infection treatment due to its highest effective dose (573.08 μg/mL) and fast release at the intestinal tract.

Chitosan Encapsulated Meloxicam Nanoparticles for Sustained Drug Delivery Applications: Preparation, Characterization, and Pharmacokinetics in Wistar Rats

Meloxicam (MLX) is currently used in the therapeutic management of both acute and chronic inflammatory disorders such as pain, injuries, osteoarthritis, and rheumatoid arthritis in both humans and animals. Gastrointestinal toxicity and occasional renal toxicity were observed in patients taking it for a long-term period. Meloxicam's late attainment of peak plasma concentration results in a slow onset of action. The goal of the current study was to prepare and characterize chitosan encapsulated meloxicam nanoparticles (CEMNPs) with high bioavailability and less gastro intestinal toxicity in order to prevent such issues. The size of the prepared CEMNPs was approximately 110-220 nm with a zetapotential of +39.9 mV and polydispersity index of 0.268, suggesting that they were uniformly dispersed nanoparticles. The FTIR and UV-Vis spectroscopy have confirmed the presence of MLX in the prepared CEMNPs. The pharmacokinetics have been studied with three groups of male Wistar rats receiving either of the treatments, viz., 4 mg·kg-1 of MLX and 1 or 4 mg·kg-1 of CEMNPs. Plasma samples were collected until 48 h post administration, and concentrations of MLX were quantified by using reverse (C18) phase HPLC. Non-compartmental analysis was applied to determine pharmacokinetic variables. Upon oral administration, the maximum concentration (Cmax) was reached in 4 h for CEMNPs and 6 h for MLX. The mean area under the plasma MLX concentration-time curve from 'zero' to infinity (AUC0-∞), half-life (t1/2β), and mean resident time (MRT) of 1 mg·kg-1 of CEMNPs was 1.4-, 2-, and 1.8-fold greater than 4 mg·kg-1 of MLX. The prepared CEMNPs demonstrated quicker absorption and prolonged release along with a significant improvement in the bioavailability of MLX, paving a prospective path for the development of drugs with enhanced bioavailability with less side effects.

Polymers Enhancing Bioavailability in Drug Delivery

A drug's bioavailability, i.e., the extent to and rate at which it enters the systemic circulation, thus accessing the site of action, is largely determined by the properties of the drug [...].

Formulation, Characterisation and Evaluation of the Antihypertensive Peptides, Isoleucine-Proline-Proline and Leucine-Lysine-Proline in Chitosan Nanoparticles Coated with Zein for Oral Drug Delivery

Isoleucine-Proline-Proline (IPP) and Leucine-Lysine-Proline (LKP) are food-derived tripeptides whose antihypertensive functions have been demonstrated in hypertensive rat models. However, peptides display low oral bioavailability due to poor intestinal epithelial permeability and instability. IPP and LKP were formulated into nanoparticles (NP) using chitosan (CL113) via ionotropic gelation and then coated with zein. Following addition of zein, a high encapsulation efficiency (EE) (>80%) was obtained for the NP. In simulated gastric fluid (SGF), 20% cumulative release of the peptides was achieved after 2 h, whereas in simulated intestinal fluid (SIF), ~90% cumulative release was observed after 6 h. Higher colloidal stability (39−41 mV) was observed for the coated NP compared to uncoated ones (30−35 mV). In vitro cytotoxicity studies showed no reduction in cellular viability of human intestinal epithelial Caco-2 and HepG2 liver cells upon exposure to NP and NP components. Administration of NP encapsulating IPP and LKP by oral gavage to spontaneously hypertensive rats (SHR) attenuated systolic blood pressure (SBP) for 8 h. This suggests that the NP provide appropriate release to achieve prolonged hypotensive effects in vivo. In conclusion, chitosan-zein nanoparticles (CZ NP) have potential as oral delivery system for the encapsulation of IPP and LKP.

Nanoscale Delivery Systems of Lutein: An Updated Review from a Pharmaceutical Perspective

Carotenoids are natural lipid-soluble pigments that produce yellow to red colors in plants as well as providing bright coloration in vegetables and fruits. Lutein belongs to the xanthophyll subgroup of the carotenoid family, which plays an essential role in photosynthesis and photoprotection in nature. In the human body, lutein, together with its isomer zeaxanthin and its metabolite meso-zeaxanthin, accumulates in the macula of the eye retina, which is responsible for central, high-resolution, and color vision. As a bioactive phytochemical, lutein has essential physiological functions, providing photoprotection against damaging blue light, along with the neutralization of oxidants and the preservation of the structural and functional integrity of cellular membranes. As a potent antioxidant and anti-inflammatory agent, lutein unfortunately has a low bioavailability because of its lipophilicity and a low stability as a result of its conjugated double bonds. In order to enhance lutein stability and bioavailability and achieve its controlled delivery to a target, nanoscale delivery systems, which have great potential for the delivery of bioactive compounds, are starting to be employed. The current review highlights the advantages and innovations associated with incorporating lutein within promising nanoscale delivery systems, such as liposomes, nanoemulsions, polymer nanoparticles, and polymer–lipid hybrid nanoparticles, as well as their unique physiochemical properties.

Impact of Degree of Ionization and PEGylation on the Stability of Nanoparticles of Chitosan Derivatives at Physiological Conditions

Nowadays, the therapeutic efficiency of small interfering RNAs (siRNA) is still limited by the efficiency of gene therapy vectors capable of carrying them inside the target cells. In this study, siRNA nanocarriers based on low molecular weight chitosan grafted with increasing proportions (5 to 55%) of diisopropylethylamine (DIPEA) groups were developed, which allowed precise control of the degree of ionization of the polycations at pH 7.4. This approach made obtaining siRNA nanocarriers with small sizes (100–200 nm), positive surface charge and enhanced colloidal stability (up to 24 h) at physiological conditions of pH (7.4) and ionic strength (150 mmol L⁻¹) possible. Moreover, the PEGylation improved the stability of the nanoparticles, which maintained their colloidal stability and nanometric sizes even in an albumin-containing medium. The chitosan-derivatives displayed non-cytotoxic effects in both fibroblasts (NIH/3T3) and macrophages (RAW 264.7) at high N/P ratios and polymer concentrations (up to 0.5 g L⁻¹). Confocal microscopy showed a successful uptake of nanocarriers by RAW 264.7 macrophages and a promising ability to silence green fluorescent protein (GFP) in HeLa cells. These results were confirmed by a high level of tumor necrosis factor-α (TNFα) knockdown (higher than 60%) in LPS-stimulated macrophages treated with the siRNA-loaded nanoparticles even in the FBS-containing medium, findings that reveal a good correlation between the degree of ionization of the polycations and the physicochemical properties of nanocarriers. Overall, this study provides an approach to enhance siRNA condensation by chitosan-based carriers and highlights the potential of these nanocarriers for in vivo studies.

Tight junctions: from molecules to gastrointestinal diseases

Intestinal epithelium functions as a tissue barrier to prevent interaction between the internal compartment and the external milieu. Intestinal barrier function also determines epithelial polarity for the absorption of nutrients and the secretion of waste products. These vital functions require strong integrity of tight junction proteins. In fact, intestinal tight junctions that seal the paracellular space can restrict mucosal-to-serosal transport of hostile luminal contents. Tight junctions can form both an absolute barrier and a paracellular ion channel. Although defective tight junctions potentially lead to compromised intestinal barrier and the development and progression of gastrointestinal (GI) diseases, no FDA-approved therapies that recover the epithelial tight junction barrier are currently available in clinical practice. Here, we discuss the impacts and regulatory mechanisms of tight junction disruption in the gut and related diseases. We also provide an overview of potential therapeutic targets to restore the epithelial tight junction barrier in the GI tract.

Green Synthesis of Silymarin-Chitosan Nanoparticles as a New Nano Formulation with Enhanced Anti-Fibrotic Effects against Liver Fibrosis

Background: Silymarin (SIL) has long been utilized to treat a variety of liver illnesses, but due to its poor water solubility and low membrane permeability, it has a low oral bioavailability, limiting its therapeutic potential. Aim: Design and evaluate hepatic-targeted delivery of safe biocompatible formulated SIL-loaded chitosan nanoparticles (SCNPs) to enhance SIL’s anti-fibrotic effectiveness in rats with CCl₄-induced liver fibrosis. Methods: The SCNPs and chitosan nanoparticles (CNPs) were prepared by ionotropic gelation technique and are characterized by physicochemical parameters such as particle size, morphology, zeta potential, and in vitro release studies. The therapeutic efficacy of successfully formulated SCNPs and CNPs were subjected to in vivo evaluation studies. Rats were daily administered SIL, SCNPs, and CNPs orally for 30 days. Results: The in vivo study revealed that the synthesized SCNPs demonstrated a significant antifibrotic therapeutic action against CCl₄-induced hepatic injury in rats when compared to treated groups of SIL and CNPs. SCNP-treated rats had a healthy body weight, with normal values for liver weight and liver index, as well as significant improvements in liver functions, inflammatory indicators, antioxidant pathway activation, and lipid peroxidation reduction. The antifibrotic activities of SCNPs were mediated by suppressing the expression of the main fibrosis mediators TGFβR1, COL3A1, and TGFβR2 by boosting the hepatic expression of protective miRNAs; miR-22, miR-29c, and miR-219a, respectively. The anti-fibrotic effects of SCNPs were supported by histopathology and immunohistochemistry (IHC) study. Conclusions: According to the above results, SCNPs might be the best suitable carrier to target liver cells in the treatment of liver fibrosis.