Polysaccharide-based micro/nanocarriers for oral colon-targeted drug delivery

Optimally designed PEGylatied arabinoxylan paclitaxel nano-micelles as alternative delivery for Abraxane®: A potential targeted therapy against breast and lung cancers

Paclitaxel (PTX) binds to spindle microtubules and inhibits mitotic division leading to cell death. However, its wide distribution, high absorption, and less selectively, minimize its application in cancer clinics. In this study, isolated arabinoxylans were used to encapsulate PTX, and then both were covered by polyethylene glycol conjugated to folic acid (FA), to strengthen its specificity to cancerous cells. Beclin-1 and P21 were significantly overexpressed by (79.6 ± 0.97 %, p ≤ 0.00001, &62.2 ± 1.15 % p ≤ 0.0001 in MCF-7 cells) and (74.8 ± 8.04 %, p ≤ 0.0001 &75.3 ± 2.3 %, p ≤ 0.0001, in NSCLCs) respectively after their incubation for 48 h with nano-targeted PTX NPs. Similarly, P53 and GSK3 beta-pSer9 were significantly increased by (63.5 ± 1 % p ≤ 0.0001, & 87 ± 1 % p ≤ 0.0001, in MCF) respectively and (81.5 ± 6 % p ≤ 0.01, & 84.8 ± 3.8 % p ≤ 0.001, in A549) respectively. The findings confirmed the activation of acidic/neutral autophagosomes in acridine orange/ethidium bromide (AO/EB) and nuclear fragmentation was clearly shown by 4', 6-diamidino-2 phenylindole (DAPI) nuclear stains. The findings provide the basis for the potential application of arabinoxylans as a great vehicle for the encapsulation of chemotherapeutic agents such as PTX for target delivery, and also as an immune mediator.

Curcumin-loaded polysaccharide microparticles alleviated DSS-induced ulcerative colitis by improving intestinal microecology and regulating MAPK/NF-κB/Nrf2/NLRP3 pathways

Curcumin (Cur) exerts many benefits on the host, but its application is limited by its poor bioavailability. In this study, composite polysaccharide microparticles loading Cur (Cur-CPM) was prepared by food-grade materials and gel technology. Its properties were analyzed via the in vitro and in vivo models, and then its benefit on gut health was assessed in DSS-treated mice. Compared to free Cur, CPM extended the residence time and absorption efficiency of Cur in the intestine, effectively ameliorating the symptoms of colitis. Cur-CPM alleviated colonic inflammation by inhibiting the activation of the MAPK and NF-κB pathways and suppressing NLRP3 inflammasome activity, affecting the expression of inflammation-related cytokines and mediators. In addition, Cur-CPM regulated the levels of antioxidants and oxidants in the colon tissues via Nrf2 activation, alleviating oxidative stress. Cur-CPM protected gut barrier function by maintaining the integrity of colonic mucosal layer and tight junction. The underlying mechanism can be attributed not only to the anti-inflammatory and antioxidant activities of Cur but also to modulation of Cur and CPM on the gut microbiota and metabolites. It suggests that Cur-CPM holds the potential to be developed as a functional component to enhance gut health.

Potential therapeutic target for polysaccharide inhibition of colon cancer progression

In recent years, colon cancer has become one of the most common malignant tumors worldwide, posing a great threat to human health. Studies have shown that natural polysaccharides have rich biological activities and medicinal value, such as anti-inflammatory, anti-cancer, anti-oxidation, and immune-enhancing effects, especially with potential anti-colon cancer mechanisms. Natural polysaccharides can not only protect and enhance the homeostasis of the intestinal environment but also exert a direct inhibition effect on cancer cells, making it a promising strategy for treating colon cancer. Preliminary clinical experiments have demonstrated that oral administration of low and high doses of citrus pectin polysaccharides can reduce tumor volume in mice by 38% (p < 0.02) and 70% (p < 0.001), respectively. These results are encouraging. However, there are relatively few clinical studies on the effectiveness of polysaccharide therapy for colon cancer, and ensuring the effective bioavailability of polysaccharides in the body remains a challenge. In this article, we elucidate the impact of the physicochemical factors of polysaccharides on their anticancer effects and then reveal the anti-tumor effects and mechanisms of natural polysaccharides on colon cancer. Finally, we emphasize the challenges of using polysaccharides in the treatment of colon cancer and discuss future applications.

Bi-functional astaxanthin macromolecular nanocarriers to alleviate dextran sodium sulfate-induced inflammatory bowel disease

Dextran sulfate sodium is one of the important members in the field of polysaccharide biotechnology, which can induce inflammatory bowel disease (IBD) in the gastrointestinal tract. Nevertheless, the application of astaxanthin (AST) and epigallocatechin-3-gallate (EGCG), known for their pronounced antioxidant and anti-inflammatory properties, is encumbered by limited stability and bioavailability. To surmount this challenge, dual nutritional macromolecular nanoparticles were provided for alleviating IBD. The forementioned strategy entailed the utilization of EGCG as a wall material via the Mannich reaction, resulting in the creation of specialized nanocarriers capable of mitochondrial targeting and glutathione-responsive AST delivery. In vitro investigations, these nanocarriers demonstrated an enhanced propensity for mitochondrial accumulation, leading to proficient elimination of reactive oxygen species and preservation of optimal mitochondrial membrane potential about 1.5 times stronger than free AST and EGCG. Crucially, in vivo experiments showed that the colon length of IBD mice treated with these nanocarriers increased by 51.29 % and facilitated the polarization of M2 macrophages. Moreover, the assimilation of these nanocarriers exerted a favorable impact on the composition of gut microbiota. These findings underscore the immense potential of dual nutrition nanocarriers in contemporaneously delivering hydrophobic biological activators through oral absorption, thereby presenting a highly promising avenue for combating IBD.

Rapidly degradable konjac glucomannan hydrogels cross-linked with olsalazine for colonic drug release

BACKGROUND

Polysaccharide hydrogel is one of the most important materials for the colon target drug release system. However, the degradation time of polysaccharide hydrogel is much longer than the retention time in the colon. The drugs are expelled from the body before being released.

OBJECTIVE

In order to match the degradation of drug carriers and their retention time in the colon, a rapidly degradable konjac glucomannan (KGM) hydrogel was designed for colon target drug release.

METHODS

A crosslinker containing azo bond, olsalazine, was used to prepare the rapidly degradable KGM hydrogel. The degradation and drug release of the hydrogels with different crosslinking densities in the normal buffer and the human fecal medium were studied to evaluate the efficiency of colon drug release.

RESULTS

More than 50% of the KGM hydrogel by weight was degraded and more than 60% of the 5-fluorouracil (5-Fu) was released within 48 h in 5% w/v human fecal medium.

CONCLUSION

The drug was released more rapidly in a simulated colon environment than in a normal buffer. Furthermore, the drug release was controlled by the degradation of the hydrogel. The KGM hydrogel containing azo crosslinker has great potential for colon drug release.

Fabrication of pH-dependent solid dispersion for oral colon-targeted delivery of notoginsenoside R1 and its protective effects on ulcerative colitis mice

Notoginsenoside R1 (R1), which originated from the rhizomes and roots of Panax notoginseng, is classified as a Biopharmaceutical Classification System class III drug with good solubility but poor oral absorption. Although R1 can alleviate the inflammation of dextran sulfate sodium (DSS)-induced colitis in mice, the problem of acid degradation and low bioavailability limit its application. The purpose of this study was aimed to design one kind of pH-dependent solid dispersion for oral colon-targeted delivery of R1. Using Eudragit S100 (ES 100) and PEG 4000 as the pH-dependent carriers, R1 solid dispersion (R1-SD) was fabricated by solvent evaporation method. Scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction analysis indicated that R1-SD was completely formed, the surface was smooth surface and the strip crystal structure of R1 disappeared. The in vitro release profile of R1-SD (R1-ES 100-PEG 4000, 1:7:1, weight ratio) exhibited that R1-SD was not released in media simulating the gastric condition (pH 1.2), but better release characteristics of the drug could be obtained in media simulating the intestinal condition (less than 30% in pH 6.8 phosphate-buffered saline and more than 90% in pH 7.6 condition). The in vitro colon absorption test showed that the absorption rate and cumulative release of R1-SD were higher than those of R1. R1-SD and R1 had apparent protective effect on colon shortening, inflammatory infiltrating tissue injury, weight loss, diarrhea, blood stool in mice with ulcerative colitis induced by DSS, and the protective effect of R1-SD was better than that of R1, which indicated R1-SD has good practical application prospects.

Oral delivery of porous starch-loaded bilayer microgels for controlled drug delivery and treatment of ulcerative colitis

We prepared one type of bilayer microgels for oral administration with three effects: pH responsiveness, time lag, and colon enzyme degradation. Combined with the dual biological effects of curcumin (Cur) for reducing inflammation and promoting repair of colonic mucosal injury, targeted colonic localization and release of Cur according to the colonic microenvironment were enhanced. The inner core, derived from guar gum and low-methoxyl pectin, afforded colonic adhesion and degradation behavior; the outer layer, modified by alginate and chitosan via polyelectrolyte interaction, achieved colonic localization. The porous starch (PS)-mediated strong adsorption allowed Cur loading in inner core to achieve a multifunctional delivery system. In vitro, the formulations exhibited good bioresponses at different pH conditions, potentially delaying Cur release in the upper gastrointestinal tract. In vivo, dextran sulfate sodium-induced ulcerative colitis (UC) symptoms were significantly alleviated after oral administration, accompanied by reduced levels of inflammatory factors. The formulations facilitated colonic delivery, allowing Cur accumulation in colonic tissue. Moreover, the formulations could alter gut microbiota composition in mice. During Cur delivery, each formulation increased species richness, decreased pathogenic bacterial content, and afforded synergistic effects against UC. These PS-loaded bilayer microgels, exhibiting excellent biocompatibility, multi-bioresponsiveness, and colon targeting, could be beneficial in UC therapy, allowing development into a novel oral formulation.

Dextran-Cholesterol Carrier Encapsulated Efficient Photosensitizer for the Photodynamic Killing of Cancer Cells

Selective photodynamic therapy (PDT) for cancer cells is more efficient and much safer. Most selective PDTs are realized by antigene-biomarker or peptide-biomarker interactions. Here, we modified dextran with hydrophobic cholesterol as a photosensitizer carrier to selectively target cancer cells, including colon cancer cells, and fulfilled selective PDT. The photosensitizer was designed with regular Aggregation-Induced Emission (AIE) units, including triphenylamine and 2-(3-cyano-4,5,5-trimethylfuran-2-ylidene)propanedinitrile. The AIE units can help to decrease the quenching effect in the aggregate state. The efficiency of the photosensitizer is further improved via the heavy atom effect after bromination modification. We found that the obtained photosensitizer nanoparticles could selectively target and ablate cancer cells after encapsulation into the dextran-cholesterol carrier. This study indicates that the polysaccharide-based carrier may have potential for cancer-targeting therapy beyond expectations.

Fabrication, characterization and emulsifying properties of agarose microgel

Agarose microgels were prepared with bottom-up approach, and the emulsifying properties of agarose microgels were investigated. Physical properties of microgels are varied with agarose concentration, and further affect the emulsifying performance of microgels. Enhanced surface hydrophobicity index and decreased particle size of microgels was recorded with the increasing of agarose concentration, which was conducive to emulsifying properties of microgels. Improved interfacial adsorption of microgels was evidenced by Dynamic surface tension and SEM. However, microscopic morphology of microgel at O/W interface indicated that increasing agarose concentration could weaken the deformability of microgels. The influence of external conditions (pH and NaCl) on the physical properties of microgels were investigated, and their effects on the emulsion stability were evaluated. Compared with acidification, NaCl was appeared to be more destructive to emulsion stability. Results indicated acidification and NaCl could decrease surface hydrophobicity index of microgels, but there was differentiation in the variation of particle size. It was inferred that deformability of microgels could make contribution to the stability of emulsion. This study verified that microgelation was a feasible scheme to improve the interfacial properties of agarose, and the influence of agarose concentration, pH, and NaCl on the emulsifying performance of microgels was investigated.

Perspectives of colon-specific drug delivery in the management of morning symptoms of rheumatoid arthritis

Rheumatoid arthritis is a chronic condition that is characterized by joint pain and inflammation. It is an autoimmune disorder in which the body tissues are erroneously attacked by the immune system of the host itself. It has been evident that rheumatoid arthritis symptoms follow a 24 h circadian rhythm and exhibit high thresholds of pain, functional disability, and stiffness predominantly early in the morning. Colon-specific drug delivery systems can be utilized in the formulations to be used in the treatment of rheumatoid arthritis. The colon-specific drug delivery system has shown promising results in the treatment of different diseases at the colonic site like Crohn's disease, ulcerative colitis, colon cancer, etc. The colon-specific drug delivery is capable of delivering the formulation at the predetermined location and predetermined time. The early morning symptoms of rheumatoid arthritis like pain and inflammation can be treated using the various approaches of the colon-specific drug delivery system because it will lead to patient compliance as the patient will not require administering the formulation immediately after waking up in the morning. This review also explains the immunological factors which may trigger rheumatoid arthritis in human beings. It further explores conventional approaches like pH-dependant, microorganisms-driven, pressure-controlled, and time-dependant formulations. By employing two or more conventional approaches given above the various novel approaches have been designed to eliminate the drawbacks of individual techniques.

Design, Development, and Optimisation of Smart Linker Chemistry for Targeted Colonic Delivery-In Vitro Evaluation

Drug targeting is necessary to deliver drugs to a specific site of action at a rate dictated by therapeutic requirements. The pharmacological action of a drug can thereby be optimised while minimising adverse effects. Numerous colonic drug delivery systems have been developed to avoid such undesirable side effects; however, these systems lack site specificity, leaving room for further improvement. The objective of the present study was to explore the potential of amino-alkoxycarbonyloxymethyl (amino-AOCOM) ether prodrugs as a general approach for future colonic delivery. To circumvent inter- and intra-subject variabilities in enzyme activities, these prodrugs do not rely on enzymes but rather are activated via a pH-triggered intramolecular cyclisation−elimination reaction. As proof of concept, model compounds were synthesised and evaluated under various pH conditions, simulating various regions of the gastrointestinal tract (GIT). Probe 15 demonstrated excellent stability under simulated stomach- and duodenum-like conditions and protected 60% of the payload in a small intestine-like environment. Moreover, 15 displayed sustained release at colonic pH, delivering >90% of the payload over 38 h. Mesalamine (Msl) prodrugs 21 and 22 were also synthesised and showed better stability than probe 15 in the simulated upper GIT but relatively slower release at colonic pH (61−68% of Msl over 48 h). For both prodrugs, the extent of release was comparable to that of the commercial product Asacol. This study provides initial proof of concept regarding the use of a cyclisation-activated prodrug for colon delivery and suggests that release characteristics still vary on a case-by-case basis.

Magnetic Platelets as a Platform for Drug Delivery and Cell Trapping

The possibility of using magnetically labeled blood cells as carriers is a novel approach in targeted drug-delivery systems, potentially allowing for improved bloodstream delivery strategies. Blood cells already meet the requirements of biocompatibility, safety from clotting and blockage of small vessels. It would solve the important problem of the patient's immune response to embedded foreign carriers. The high efficiency of platelet loading makes them promising research objects for the development of personalized drug-delivery systems. We are developing a new approach to use platelets decorated with magnetic nanoparticles as a targeted drug-delivery system, with a focus on bloodstream delivery. Platelets are non-nuclear blood cells and are of great importance in the pathogenesis of blood-clotting disorders. In addition, platelets are able to attach to circulating tumor cells. In this article, we studied the effect of platelets labeled with BSA-modified magnetic nanoparticles on healthy and cancer cells. This opens up broad prospects for future research based on the delivery of specific active substances by this method.

Advancement in Therapeutic Intervention of Prebiotic-Based Nanoparticles for Colonic Diseases

Intestinal flora has become a therapeutic target for the intervention of colonic diseases (CDs) with better understanding of the interplay between microbiota and CDs. Depending on unique properties and prominent ability of regulating the intestinal flora, prebiotics can not only achieve a colon-specific drug delivery but also maintain the intestinal homeostasis, thus playing a positive role in the intervention of CDs. Currently, different studies on prebiotic-based nanoparticles have been contrived for colonic drug delivery and have shown great potential in curing various CDs, such as colitis and colorectal cancer. Nevertheless, there is a lack of systematic survey on the use of prebiotic nanoparticles for the treatment of CDs. This review aims to generalize the state-of-the-art of prebiotic nanomedicines specific for CDs. The species and function of intestinal flora and various kinds of prebiotics available as well as their regulating effects on intestinal flora were expounded. A variety of prebiotic nanoparticles pertinent to colon-targeted drug delivery systems were illustrated with particular emphasis on their curative activities on CDs. The efficacy and safety of prebiotic-based colonic drug delivery systems (p-CDDs) were also analyzed. In conclusion, the synergy between prebiotic nanoparticles and their cargos may hold promise for the treatment and intervention of CDs.

pH/ROS Dual-Sensitive Natural Polysaccharide Nanoparticles Enhance "One Stone Four Birds" Effect of Rhein on Ulcerative Colitis

Rhein (RH), a natural anthraquinone compound, is considered an effective treatment candidate for ulcerative colitis (UC), whose multiple biological activities contribute to UC, including anti-inflammation, antioxidation, intestinal barrier repair, and microflora regulation. However, the application of RH is severely limited by its low water solubility, low bioavailability, and poor colonic targeting. Although some nanoparticles have been developed for the oral delivery of RH, most of them mainly highlighted only one effect of some drug delivery strategies but the above multiple biological activities. Therefore, a multiple polysaccharide-based nanodelivery system, comprising chitosan (CS) and fucoidan (FU), with pH/reactive oxygen species (ROS) sensitivity and mucosal adhesion, was developed and first used to load RH as a comprehensive treatment for UC. Briefly, RH-F/C-NPs were prepared using the polyelectrolyte self-assembly method; the average size of RH-F/C-NPs was 233.1 ± 5.7 nm, and the encapsulation rate of RH was 93.67 ± 1.60%. And it could maintain gastric stability and release RH in the colon with the designed pH/ROS sensitivity contributed by the polysaccharide-based structures. Cellular uptake experiments showed that both NCM 460 cells and RAW 264.7 cells had a good uptake of RH-F/C-NPs. Importantly, the effects of RH were highlighted in in vivo experiments, the results of which showed that RH-F/C-NPs could significantly reduce DSS-induced inflammation by inhibiting the TLR4/NF-κB-mediated anti-inflammatory pathway, the Nrf2/HO-1-mediated antioxidant pathway, colonic mucosal barrier repair, and intestinal microflora regulation. In addition, pharmacokinetic studies have shown that F/C-NPs contribute to the increase in the plasma concentration and the accumulation of RH in the colon to some extent. In short, this study is the first to develop an oral multiple polysaccharide-based nanosystem with pH/ROS dual sensitivity to study the "one stone four birds" therapeutic effect of RH on UC.

Carbohydrate Polymer-Based Targeted Pharmaceutical Formulations for Colorectal Cancer: Systematic Review of the Literature

Colon cancer is the third most diagnosed cancer worldwide, followed by lung and breast cancer. Conventional treatment methods are associated with numerous side effects and compliance issues. Thus, colon targeted drug delivery has gained much attention due to its evident advantages. Although many technologies have been explored, the use of pH-sensitive polymers, especially biodegradable polymers, holds exceptional promise. This review aims to collate research articles concerning recent advances in this area. A systematic search using multiple databases (Google Scholar, EMBASE, PubMed, MEDLINE and Scopus) was carried out following the preferred reported items for systematic reviews and meta-analyses (PRISMA) guidelines with an aim to explore the use of pH-sensitive carbohydrate polymers in developing colon targeted pharmaceutical formulations. Following screening and quality assessment for eligibility, 42 studies were included, exploring either single or a combination of carbohydrate polymers to develop targeted formulations for colon cancer therapy. Pectin (11) is the most widely used of these biopolymers, followed by chitosan (09), alginate (09) and guar gum (08). This systematic review has successfully gathered experimental evidence highlighting the importance of employing carbohydrate polymers in developing targeting formulations to manage colon cancer.

Nanoparticles for oral delivery: targeted therapy for inflammatory bowel disease

As a group of chronic and idiopathic gastrointestinal (GI) disorders, inflammatory bowel disease (IBD) is characterized by recurrent intestinal mucosal inflammation. Oral administration is critical for the treatment of IBD. Unfortunately, it is difficult to target the bowel located in the GI tract due to multiple physical barriers. The unique physicochemical properties of nanoparticle-based drug delivery systems (DDSs) and their enhanced permeability and retention effects in the inflamed bowel, render nanomedicines to be used to implement precise drug delivery at diseased sites in IBD therapy. In this review, we described the pathophysiological features of IBD, and designed strategies to exploit these features for intestinal targeting. In addition, we introduced the types of currently developed nano-targeted carriers, including synthetic nanoparticle-based and emerging naturally derived nanoparticles (e.g., extracellular vesicles and plant-derived nanoparticles). Moreover, recent developments in targeted oral nanoparticles for IBD therapy were also highlighted. Finally, we presented challenges associated with nanotechnology and potential directions for future IBD treatment.

Arabinoxylan-Based Microcapsules Being Loaded with Bee Products as Bioactive Food Components Are Able to Modulate the Cell Migration and Inflammatory Response-In Vitro Study

The aim of the research was to use bioactive heteropolysaccharides isolated from rye bran to obtain innovative systems for the controlled release of bioactive compounds. The core of the obtained encapsulates was honey and royal jelly. It was shown for the first time that preparations effectively ameliorated inflammatory response in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages, decreasing the secretion of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and nitric oxide (NO). The in vitro digestion process revealed that bee products’ encapsulates were stronger oxidative stress reducers and had sustained ability to reduction in inflammation state mediators. The lack of inhibitory effect on migration rate of human microvascular endothelial cells (HMEC-1) endothelial cells and mouse embryonic fibroblasts (NIH-3T3), both cell models involved in wound healing process, additionally identified these preparations as agents potentially used in the management of inflammatory response. In the process of a simulated digestion in vitro, the innovative microcapsules showed 85% higher biostability and two to ten times better bioavailability, compared to natural bee products.

Calcium Ion-Sodium Alginate-Piperine-Based Microspheres: Evidence of Enhanced Encapsulation Efficiency, Bio-Adhesion, Controlled Delivery, and Oral Bioavailability of Isoniazid

Isoniazid (INH) is a first-line chemotherapeutic drug employed in the management of tuberculosis. However, its extensive first-pass metabolism, short-life life, and low oral bioavailability confined its medical application. Therefore, the calcium ion-alginate-piperine microspheres (INH-CaSP Ms) was prepared to enhance encapsulation efficiency, controlled delivery, and oral bioavailability of INH. The INH-CaSP Ms was developed using a modified emulsification method and optimized via Box-Behnken design (BBD). Optimized INH-CaSP Ms were characterized for encapsulation efficiency, differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), bio-adhesion, in vitro dissolution, ex vivo permeation, and oral bioavailability studies. Characterization studies confirmed the formation of microspheres. The INH-CaSP Ms showed spherical microspheres with enhanced encapsulation efficiency (~ 93.03 ± 1.54% w/w). The optimized INH-CaSP Ms exhibited higher bio-adhesion around (~ 81.41 ± 1.31%). The INH-CaSP Ms enhanced the dissolution rate of INH (~ 57%) compared to pure INH (~ 57%) and INH-SA Ms (~ 81%) in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4). The same formulations improved the permeation rate of INH (~ 90%) compared to pure INH (~ 55%) and INH-SA Ms (~ 80%). The oral bioavailability results indicated that INH-CaSP Ms appreciably improved the oral bioavailability of INH via increasing the Cmax, Tmax, t_1/2, and AUC parameters compared to pure INH. The study demonstrates that the development of INH-CaSP Ms via cross-linked coordinate bond interaction between divalent cation calcium ion-alginate complex and anion piperine bio-enhancer is an effective approach for enhancing the encapsulation efficiency, bio-adhesion, controlled release, and oral bioavailability of INH.

Advances in the treatment of inflammatory bowel disease: Focus on polysaccharide nanoparticulate drug delivery systems

The complex pathogenesis of inflammatory bowel disease (IBD) explains the several hurdles for finding an efficient approach to cure it. Nowadays, therapeutic protocols aim to reduce inflammation during the hot phase or maintain remission during the cold phase. Nonetheless, these drugs suffer from severe side effects or poor efficacy due to low bioavailability in the inflamed region of the intestinal tract. New protocols based on antibodies that target proinflammatory cytokines are clinically relevant. However, besides being expensive, their use is associated with a primary nonresponse or a loss of response following a long administration period. Accordingly, many researchers exploited the physiological changes of the mucosal barrier for designing nanoparticulate drug delivery systems to target inflamed tissues. Others exploited biocompatibility and relative affordability of polysaccharides to test their intrinsic anti-inflammatory and healing properties in IBD models. This critical review updates state of the art on advances in IBD treatment. Data on using polysaccharide nanoparticulate drug delivery systems for IBD treatment are reviewed and discussed.

Rheological and textural analysis as tools for investigation of drug-polymer and polymer-polymer interactions on the example of low-acyl gellan gum and mesalazine

PURPOSE

In the performed study, the rheological and textural parameters of gellan-based hydrogels were investigated and their dependence on three factors was taken into consideration: (i) The presence of the model drug, (ii) The presence and type of the ionic crosslinking agent, and (iii) the composition of the polymer network. The objective was to compare two analytical methods, regarded as complementary, and define to what extent the obtained results correlate with each other.

METHODS

The hydrogels contained low-acyl gellan gum or its mixtures with hydroxyethyl cellulose or κ-carrageenan. CaCl₂ and MgCl₂ were used as gelling agents. Mesalazine was used as a model drug. The rheological analysis included oscillatory stress and frequency sweeping. The texture profile analysis was performed to calculate texture parameters.

RESULTS

Placebo gels without the addition of gelling agents had the weakest structure. The drug had the strongest ability to increase the stiffness of the polymer network. The weakest structure revealed the placebo samples without the addition of gelling agents. Texture analysis revealed no significant influence of the drug on the strength of the gels, while rheological measurements indicated clear differences.

CONCLUSIONS

It can be concluded that in the case of some parameters methods correlate, that is, the effect related to gelling ions. However, the rheological analysis seems to be more precise and sensitive to some changes in the mechanical properties of the gels.

Polysaccharide-Based Nanoparticles for Colon-Targeted Drug Delivery Systems

Polysaccharide biomaterials have gained significant importance in the manufacture of nanoparticles used in colon-targeted drug delivery systems. These systems are a form of non-invasive oral therapy used in the treatment of various diseases. To achieve successful colonic delivery, the chemical, enzymatic and mucoadhesive barriers within the gastrointestinal (GI) tract must be analyzed. This will allow for the nanomaterials to cross these barriers and reach the colon. This review provides information on the development of nanoparticles made from various polysaccharides, which can overcome multiple barriers along the GI tract and affect encapsulation efficiency, drug protection, and release mechanisms upon arrival in the colon. Also, there is information disclosed about the size of the nanoparticles that are usually involved in the mechanisms of diffusion through the barriers in the GI tract, which may influence early drug degradation and release in the digestive tract.

5-Aminosalicylic Acid Loaded Chitosan-Carrageenan Hydrogel Beads with Potential Application for the Treatment of Inflammatory Bowel Disease

The aim of our work is to prepare mucoadhesive particles with biopolymers and 5-Aminosalicylic acid (5ASA) using the ionotropic gelation technique to ensure a controlled drug release at the colon level with potential applications in the treatment of intestinal bowel disease (IBD). The preparation of particles through the crosslinking of Chitosan (CS) with sodium tripolyphosphate (TPP) using different mass ratios and the influence of the k-Carrageenan (kCG) layer were studied. UV–VIS spectrometry was employed to assess encapsulation efficiency and drug release profile of 5ASA. The particles were investigated using FT-IR spectrometry for chemical characterization and the DLS results highlighted a monodisperse particle size distribution. The morphology of the polymeric beads was investigated using micro-computer tomography (µCT) and Scanning Electron Microscopy (SEM). Particles based on Chitosan and k-Carrageenan were able to incorporate and preserve 5ASA in an acidic and alkaline medium. The 5ASA loaded polymeric particles obtained after immersion for 1 h in kCG solution exhibited the lowest release rate in pH = 1.2. Biocompatibility studies performed on all of the particles displayed a good viability for the CCD 841 CoN cells and low cytotoxicity. All of the results have shown that these new biomaterials could be a versatile platform of targeted carriers with potential applications in inflammatory bowel disease treatment.

Mechanism of Lentinan Intestinal Absorption: Clathrin-Mediated Endocytosis and Macropinocytosis

Lentinan (LNT), a typical triple helix β-glucan extracted from Lentinus edodes, has been widely used as a functional food and an orally administered drug. However, its oral pharmacokinetics has been rarely reported. The aim of this work is to systematically study the pharmacokinetics and intestinal absorption mechanism of LNT after oral administration. Radioactive 99m-technetium (^99mTc) was introduced to label LNT to determine the plasma concentration, tissue distribution, and excretion of the β-glucan in rats after oral administration. The results confirmed the absorption of LNT, with the maximal plasma concentration reached at 1 h. 5-([4,6-Dichlorotriazin-2-yl]amino)fluorescein (DTAF) was used to label LNT to explore the absorption mechanism of LNT, utilizing both a Ussing chamber and a monolayer of Caco-2 cells. These transport assays showed that LNT could penetrate through the intestine and epithelial monolayer, which was mediated by macropinocytosis and clathrin-mediated endocytosis. These findings provide a pharmacokinetic reference for LNT and help provide a greater understanding of the absorption of β-glucans in general.

Budesonide-Loaded Pectin/Polyacrylamide Hydrogel for Sustained Delivery: Fabrication, Characterization and In Vitro Release Kinetics

A single ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that causes inflammation of the colonic mucosa at the distal colon and rectum. The mainstay therapy involves anti-inflammatory immunosuppression based on the disease location and severity. The disadvantages of using systemic corticosteroids for UC treatment is the amplified risk of malignancies and infections. Therefore, topical treatments are safer as they have fewer systemic side effects due to less systemic exposure. In this context, pH sensitive and enzymatically triggered hydrogel of pectin (PC) and polyacrylamide (PAM) has been developed to facilitate colon-targeted delivery of budesonide (BUD) for the treatment of UC. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), swelling ratio, and drug release. FT-IR spectroscopy confirmed the grafting as well loading of BUD in hydrogel. XRD showed the amorphous nature of hydrogel and increment in crystallinity after drug loading. On the other hand, SEM showed that the hydrogels exhibited a highly porous morphology, which is suitable for drug loading and also demonstrated a pH-responsive swelling behaviour, with decreased swelling in acidic media. The in-vitro release of BUD from the hydrogel exhibited a sustained release behaviour with non-ficken diffusion mechanism. The model that fitted best for BUD released was the Higuchi kinetic model. It was concluded that enzyme/pH dual-sensitive hydrogels are an effective colon-targeted delivery system for UC.

Oral delivery of micro/nanoparticulate systems based on natural polysaccharides for intestinal diseases therapy: Challenges, advances and future perspectives

Colon-targeted oral delivery of drugs remains as an appealing and promising approach for the treatment of prevalent intestinal diseases (ID), such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Notwithstanding, there are numerous challenges to effective drug delivery to the colon, which requires the design of advanced strategies. Micro- and nanoparticles have received great attention as colon-targeted delivery platforms due to their reduced size and structural composition that favors the accumulation and/or residence time of drugs at the site of action and/or absorption, contributing to localized therapy. The choice by natural polysaccharides imparts key properties and advantages to the nano-in-microparticulate systems to effective colon-specific oral delivery. This review proposes to discuss the physiological barriers imposed by the gastrointestinal tract (GIT) against oral administration of drugs, as well as pathological factors and challenges of the ID for oral delivery of colon-targeted systems. We then provide an updated progress about polysaccharides-based colon-targeted drug delivery systems, including microparticulate, nanoparticulate and nano-in-microparticulate systems, highlighting their key properties, advantages and limitations to achieving targeted delivery and efficacious therapy within the colon. Lastly, we provide future perspectives, towards advances in the field and clinical translation of colon-targeted oral delivery systems for ID therapy.

Targeting strategies of oral nano-delivery systems for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder of gastrointestinal tract with rising incidence. Established treatments of IBD are characterized by significantly adverse effects, insufficient therapeutic efficacy. Employing the oral nano-drug delivery systems for targeted therapy is capable of effectively avoiding systematic absorption and increasing local drug concentration, consequently leading to decreased adverse effects and improved therapeutic outcomes. This review gives a brief profile of pathophysiological considerations in terms of developing disease-directed drug delivery systems, then focuses on mechanisms and strategies of current oral nano-drug delivery systems, including size-, enzyme-, redox-, pH-, ligand-receptor-, mucus-dependent systems, and proposes the future directions of managements for IBD.

Therapeutic targeting of the oncogenic Wnt signaling pathway for treating colorectal cancer and other colonic disorders

The canonical Wnt pathway is one of the key cellular signaling cascades that regulates, via the transcriptional co-activator β-catenin, numerous embryogenic developmental processes, as well as tissue homeostasis. It is therefore not surprising that misregulation of the Wnt/β-catenin pathway has been implicated in carcinogenesis. Aberrant Wnt signaling has been reported in a variety of malignancies, and its role in both hereditary and sporadic colorectal cancer (CRC), has been the subject of intensive study. Interestingly, the vast majority of colorectal tumors harbor mutations in the tumor suppressor gene adenomatous polyposis coli (APC). The Wnt pathway is complex, and despite decades of research, the mechanisms that underlie its functions are not completely known. Thus, although the Wnt cascade is an attractive target for therapeutic intervention against CRC, one of the malignancies with the highest morbidity and mortality rates, achieving efficacy and safety is yet extremely challenging. Here, we review the current knowledge of the Wnt different epistatic signaling components and the mechanism/s by which the signal is transduced in both health and disease, focusing on CRC. We address some of the important questions in the field and describe various therapeutic strategies designed to combat unregulated Wnt signaling, the development of targeted therapy approaches and the emerging challenges that are associated with these advanced methods.

Development of nitazoxanide-loaded colon-targeted formulation for intestinal parasitic infections: centre composite design-based optimization and characterization

Background

The current investigation is focused on the development and characterization of Eudragit S100 coated nitazoxanide-loaded microbeads as colon-targeted system utilizing central composite design (CCD) and desirability function. The study initiated with the selection of a BCS class II drug nitazoxanide and its preformulation screening with excipients, selection of polymer and identification of concentration for CCD, selection of optimized formulation based on desirability function, and in vitro release studies in simulated gastric and colonic media and stability studies. A two-factor, three-level CCD was employed with two independent variables, i.e. X1 (chitosan % w/v) and X2 (sodium tripolyphosphate % w/v), and three dependent variables, i.e. Y1 (particle size in micrometres), Y2 (percentage yield) and Y3 (percent entrapment efficiency), were chosen. Additionally, surface morphology, mucoadhesion and in vitro drug release studies were also conducted.

Result

Chitosan concentration showing maximum entrapment and optimum particle size was selected to formulate chitosan beads. The polynomial equation and model graphs obtained from the Design-Expert were utilized to examine the effect of independent variables on responses. The effect of formulation composition was found to be significant (p ˂ 0.05). Based on the desirability function, the optimized formulation was found to have 910.14 μm ± 1.03 particle size, 91.84% ± 0.64 percentage yield and 84.75% ± 0.38 entrapment efficiency with a desirability of 0.961. Furthermore, the formulations were characterized for in vitro drug release in simulated colonic media (2% rat caecal content) and have shown a sustained release of ∼ 92% up to 24 h as compared to in vitro release in simulated gastric fluid.

Conclusion

The possibility of formulation in enhancing percentage yield and entrapment efficiency of nitazoxanide and the utilization of CCD helps to effectively integrate nitazoxanide microbeads into a potential pharmaceutical dosage form for sustained release.

Development of pH-Responsive Biopolymeric Nanocapsule for Antibacterial Essential Oils

It is generally believed that antibacterial essential oils have the potential to become one of the alternatives in preventing diarrheal diseases of monogastric animals. The disadvantage is their low efficiency per oral due to easy degradation during digestion in the stomach. This study compares the efficacy of chitosan, alginate-chitosan, guar gum-chitosan, xanthan gum-chitosan and pectin-chitosan nanocapsules to the synthesis of pH-responsive biopolymeric nanocapsule for Thymus vulgaris, Rosmarinus officinalis and Syzygium aromaticum essential oils. Using spectrophotometric approach and gas chromatography, release kinetics were determined in pH 3, 5.6 and 7.4. The growth rates of S. aureus and E. coli, as well as minimal inhibition concentration of essential oils were studied. The average encapsulation efficiency was 60%, and the loading efficiency was 70%. The size of the nanocapsules ranged from 100 nm to 500 nm. Results showed that chitosan-guar gum and chitosan-pectin nanocapsules released 30% of essential oils (EOs) at pH 3 and 80% at pH 7.4 during 3 h. Similar release kinetics were confirmed for thymol, eugenol and α-pinene. Minimal inhibition concentrations of Thymus vulgaris and Syzygium aromaticum essential oils ranged from 0.025 to 0.5%. Findings of this study suggest that the suitable pH-responsive nanocapsule for release, low toxicity and antibacterial activity is based on chitosan-guar gum structure.

An Orally Administrated Hyaluronan Functionalized Polymeric Hybrid Nanoparticle System for Colon-Specific Drug Delivery

There is a pressing clinical need for advanced colon-specific local drug delivery systems that can provide major advantages in treating diseases associated with the colon, such as inflammatory bowel disease (IBD) and colon cancer. A precise colon targeted drug delivery platform is expected to reduce drug side effects and increase the therapeutic response at the intended disease site locally. In this study, we report the fabrication of hyaluronan (HA) functionalized polymeric hybrid nanoparticulate system (Cur-HA NPs) by using curcumin as a model fluorescent drug. The Cur-HA NPs were about 200–300 nm in size, −51.3 mV overall surface charge after HA functionalization, with 56.0% drug released after 72 h in simulated gastrointestinal fluids. The Cur-HA NPs did not exhibit any cytotoxicity by AlamarBlue, PicoGreen and Live/Dead assays. Following the Cur-HA NPs use on HT-29 monolayer cell cultures demonstrating, the efficacy of HA functionalization increases cellular interaction, uptake when compared to uncoated nanoparticulate system. These findings indicate that HA functionalized nano-hybrid particles are effective in delivering drugs orally to the lower gastrointestinal tract (GIT) in order to treat local colonic diseases.

Arabinoxylan-Based Particles: In Vitro Antioxidant Capacity and Cytotoxicity on a Human Colon Cell Line

Background and objectives: Arabinoxylans (AX) can gel and exhibit antioxidant capacity. Previous studies have demonstrated the potential application of AX microspheres as colon-targeted drug carriers. However, the cytotoxicity of AX gels has not been investigated so far. Therefore, the aim of the present study was to prepare AX-based particles (AXM) by coaxial electrospraying method and to investigate their antioxidant potential and cytotoxicity on human colon cells. Materials and Methods: The gelation of AX was studied by monitoring the storage (G') and loss (G'') moduli. The morphology of AXM was evaluated using optical and scanning electron microscopy (SEM). The in vitro antioxidant activity of AX before and after gelation was measured using the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. In addition, the effect of AX and AXM on the proliferation of human colon cells (CCD 841 CoN) was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: The final G' and G'' values for AX gels were 293 and 0.31 Pa, respectively. AXM presented spherical shape and rough surface with a three-dimensional and porous network. The swelling ratio and mesh size of AXM were 35 g water/g AX and 27 nm, respectively. Gelation decreased the antioxidant activity of AX by 61-64 %. AX and AXM did not affect proliferation or show any toxic effect on the normal human colon cell line CCD 841 CoN. Conclusion: The results indicate that AXM could be promising biocompatible materials with antioxidant activity.

Advances in orally targeted drug delivery to colon

Colon-specific drug delivery is critical for treating diseases of colon, such as colon cancer, amoebiasis, irritable bowel syndrome, and inflammatory bowel disease. This study reviews the effects of targeted oral drug delivery on patient by measuring the accurate administration of the drug to specific disease spot, thus enhancing the therapeutic efficacy and provides better therapeutic outcomes. Medically targeted delivery to colon produces local effect on the diseases and hinders the systemic toxic effects of drugs. The delivery of therapeutics to the specific diseased part of colon has its merits over systemic drug delivery, albeit has some obstacles and problems. Colon drug delivery can be used to create both systemic and local effects. Many advanced approaches are used, such as conventional methods for drug release to colon, delayed release dosage forms, nanoparticles, carbon nanotubes, dendrimers, and alginate coated microparticles. This concise review summarizes and elaborates the details of different techniques and strategies on targeted oral drug delivery to colon as well as studies the advantages, disadvantages, and limitations to improve the application of drug in the part of the affected colon.

Ferulated Arabinoxylans and Their Gels: Functional Properties and Potential Application as Antioxidant and Anticancer Agent

In the last years, biomedical research has focused its efforts in the development of new oral delivery systems for the treatment of different diseases. Ferulated arabinoxylans are polysaccharides from cereals that have been gaining attention in the pharmaceutical field due to their prebiotic, antioxidant, and anticancer properties. The antioxidant and anticancer properties of these polysaccharides make them attractive compounds for the treatment of cancer, particularly colon cancer. In addition, ferulated arabinoxylans can form covalent gels through the cross-linking of their ferulic acids. Due to their particular characteristics, ferulated arabinoxylan gels represent an excellent alternative as colon-targeted drug delivery systems. The aim of the present work is to review the physicochemical and functional properties of ferulated arabinoxylans and their gels and to present the future perspectives for potential application as antioxidant and anticancer agents.

Degradation studies of modified inulin as potential encapsulation material for colon targeting and release of mesalamine

Due to the potential to treat colon specific diseases with reduced side effects, colon targeting has become of high interest over the last decades. Chemical modified inulin was investigated for its potential as encapsulation material regarding its enzymatic degradability and its drug release behavior. Different degrees of acetylated inulin (degree of substitution, DS, 0.3-2.1) were synthesized. The chemical modification leads to a reduction in enzymatic degradability by inulinase and esterase, enzymes which can be expressed by the colon microbiota. Acetylated inulin was only hydrolyzed to fructose units up to DS of 1.3. Microparticles made of native inulin and acetylated inulin (DS 1.8) were loaded with the colon-specific drug mesalamine by spray drying. Compared to the burst release of mesalamine by inulin particles within 6 h, acetylated inulin particles showed less burst release followed by a continuous drug release phase caused by diffusion up to 30% mesalamine after 52 h.

Nanoparticle-Based Oral Drug Delivery Systems Targeting the Colon for Treatment of Ulcerative Colitis

10.1093/ibd/izy123_video1izy123.video15786481867001.

Nanoparticles for oral delivery: Design, evaluation and state-of-the-art

The oral route is a preferred method of drug administration, though achieving effective drug delivery and minimizing off-target side effects is often challenging. Formulation into nanoparticles can improve drug stability in the harsh gastrointestinal (GI) tract environment, providing opportunities for targeting specific sites in the GI tract, increasing drug solubility and bioavailability, and providing sustained release in the GI tract. However, the unique and diverse physiology throughout the GI tract, including wide variation in pH, mucus that varies in thickness and structure, numerous cell types, and various physiological functions are both a barrier to effective delivery and an opportunity for nanoparticle design. Here, nanoparticle design aspects to improve delivery to particular sites in the GI tract are discussed. We then review new methods for evaluating oral nanoparticle formulations, including a short commentary on data interpretation and translation. Finally, the state-of-the-art in preclinical targeted nanoparticle design is reviewed.