Polysaccharides for Colon Targeted Drug Delivery

Film Coating of Phosphorylated Mandua Starch on Matrix Tablets for pH-Sensitive Release of Mesalamine

Chemically modified mandua starch was successfully synthesized and applied to coat mesalamine-loaded matrix tablets. The coating material was an aqueous dispersion of mandua starch modified by sodium trimetaphosphate and sodium tripolyphosphate. To investigate the colon-targeting release competence, chemically modified mandua starch film-coated mesalamine tablets were produced using the wet granulation method followed by dip coating. The effect of the coating on the colon-targeted release of the resultant delivery system was inspected in healthy human volunteers and rabbits using roentgenography. The results show that drug release was controlled when the coating level was 10% w/w. The release percentage in the upper gastric phase (pH 1.2, simulated gastric fluid) was less than 6% and reached up to 59.51% w/w after 14 h in simulated colonic fluid. In addition to in vivo roentgenographic studies in healthy rabbits, human volunteer studies proved the colon targeting efficiency of the formulation. These results clearly demonstrated that chemically modified mandua starch has high effectiveness as a novel aqueous coating material for controlled release or colon targeting.

Recent updates on guar gum derivatives in colon specific drug delivery

Colon specific delivery of therapeutics have gained much attention of pharmaceutical researchers in the recent past. Colonic specific targeting of drugs is used not only for facilitating absorption of protein or peptide drugs, but also localization of therapeutic agents in colon to treat several colonic disorders. Among various biopolymers, guar gum (GG) exhibits pH dependent swelling, which allows colon specific release of drug. GG also shows microbial degradation in the colonic environment which makes it a suitable excipient for developing colon specific drug delivery systems. The uncontrolled swelling and hydration of GG can be controlled by structural modification or by grafting with another polymeric moiety. Several graft copolymerized guar gum derivatives are investigated for colon targeting of drugs. The efficacy of various guar gum derivatives are evaluated for colon specific delivery of drugs. The reviewed literature evidenced the potentiality of guar gum in localizing drugs in the colonic environment. This review focuses on the synthesis of several guar gum derivatives and their application in developing various colon specific drug delivery systems including matrix tablets, coated formulations, nano or microparticulate delivery systems and hydrogels.

Colon Drug Delivery Systems Based on Swellable and Microbially Degradable High-Methoxyl Pectin: Coating Process and In Vitro Performance

Oral colon delivery systems based on a dual targeting strategy, harnessing time- and microbiota-dependent release mechanisms, were designed in the form of a drug-containing core, a swellable/biodegradable polysaccharide inner layer and a gastroresistant outer film. High-methoxyl pectin was employed as the functional coating polymer and was applied by spray-coating or powder-layering. Stratification of pectin powder required the use of low-viscosity hydroxypropyl methylcellulose in water solution as the binder. These coatings exhibited rough surfaces and higher thicknesses than the spray-coated ones. Using a finer powder fraction improved the process outcome, coating quality and inherent barrier properties in aqueous fluids. Pulsatile release profiles and reproducible lag phases of the pursued duration were obtained from systems manufactured by both techniques. This performance was confirmed by double-coated systems, provided with a Kollicoat® MAE outer film that yielded resistance in the acidic stage of the test. Moreover, HM pectin-based coatings manufactured by powder-layering, tested in the presence of bacteria from a Crohn's disease patient, showed earlier release, supporting the role of microbial degradation as a triggering mechanism at the target site. The overall results highlighted viable coating options and in vitro release characteristics, sparking new interest in naturally occurring pectin as a coating agent for oral colon delivery.

Guar gum as a microbially degradable component for an oral colon delivery system based on a combination strategy: formulation and in vitro evaluation

Oral colon delivery has widely been pursued exploiting naturally occurring polysaccharides degraded by the resident microbiota. However, their hydrophilicity may hinder the targeting performance. The aim of the present study was to manufacture and evaluate a double-coated delivery system leveraging intestinal microbiota, pH, and transit time for reliable colonic release. This system comprised a tablet core, a hydroxypropyl methylcellulose (HPMC) inner layer and an outer coating based on Eudragit® S and guar gum. The tablets were loaded with paracetamol, selected as a tracer drug because of the well-known analytical profile and lack of major effects on bacterial viability. The HPMC and Eudragit® S layers were applied by film-coating. Tested for in vitro release, the double-coated systems showed gastroresistance in 0.1 N HCl followed by lag phases of consistent duration in phosphate buffer pH 7.4, imparted by the HPMC layer and synergistically extended by the Eudragit® S/guar gum one. In simulated colonic fluid with fecal bacteria from an inflammatory bowel disease patient, release was faster than in the presence of β-mannanase and in control culture medium. The bacteria-containing fluid was obtained by an experimental procedure making multiple tests possible from a single sampling and processing run. Thus, the study conducted proved the feasibility of the delivery system and ability of guar gum to trigger release in the presence of colon bacteria without impairing the barrier properties of the coating. Finally, it allowed an advantageous simulated colonic fluid preparation procedure to be set up, reducing the time, costs, and complexity of testing and enhancing replicability.

A Review of Natural Polysaccharides: Sources, Characteristics, Properties, Food, and Pharmaceutical Applications

Natural polysaccharides, which are described in this study, are some of the most extensively used biopolymers in food, pharmaceutical, and medical applications, because they are renewable and have a high level of biocompatibility and biodegradability. The fundamental understanding required to properly exploit polysaccharides potential in the biocomposite, nanoconjugate, and pharmaceutical industries depends on detailed research of these molecules. Polysaccharides are preferred over other polymers because of their biocompatibility, bioactivity, homogeneity, and bioadhesive properties. Natural polysaccharides have also been discovered to have excellent rheological and biomucoadhesive properties, which may be used to design and create a variety of useful and cost-effective drug delivery systems. Polysaccharide-based composites derived from natural sources have been widely exploited due to their multifunctional properties, particularly in drug delivery systems and biomedical applications. These materials have achieved global attention and are in great demand because to their biochemical properties, which mimic both human and animal cells. Although synthetic polymers account for a substantial amount of organic chemistry, natural polymers play a vital role in a range of industries, including biomedical, pharmaceutical, and construction. As a consequence, the current study will provide information on natural polymers, their biological uses, and food and pharmaceutical applications.

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.

Exploring β-glucan as a micro-nano system for oral delivery targeted the colon

The critical role of oral colon-specific delivery systems (OCDDS) is important for delivering active agents to the colon and rectum specifically via the oral route. The use of micro/nanostructured OCDDS further improves drug stability, bioavailability, and retention time, leading to enhanced therapeutic effects. However, designing micro/nanoscale OCDDSs is challenging due to pH changes, enzymatic degradation, and systemic absorption and metabolism. Biodegradable natural polysaccharides are a promising solution to these problems, and β-glucan is one of the most promising natural polysaccharides due to its unique structural features, conformational flexibility, and specific processing properties. This review covers the diverse chemical structures of β-glucan, its benefits (biocompatibility, easy modification, and colon-specific degradation), and various β-glucan-based micro/nanosized OCDDSs, as well as their drawbacks. The potential of β-glucan offers exciting new opportunities for colon-specific drug delivery.

Short-chain glucan self-assembly for green synthesis of functional biomaterials: Mechanism, synthesis, and microstructural control

Short-chain glucan (SCG) is a linear homopolymer containing 10 to 50 glucose units linked with α(1,4) glycosidic bonds. With its abundant, low-cost, nontoxic, biodegradable/biocompatible nature, self-assembled SCG particles (SSC) have emerged as functional biomaterials, which have recently attracted tremendous attentions in various fields. SCG self-assembly occurs through the spontaneous association of molecules under equilibrium conditions into stable and structurally well-defined nanoscale or micrometer-scale aggregates, which is governed by various intermolecular non-covalent interactions, including hydrogen-bonding, electrostatic, hydrophobic, and van der Waals. With precise and effective control of the self-assembly process of SSC, its structural modulation and function integration can be expected. Thus, we convinced that SCG self-assembly could provide an effective means of developing starch-based functional biomaterials with beneficial health properties and wide application in food industries. In this review, we provide an overview of recent advances in the green approach for the self-assembly of SSC, as well as the influence of thermodynamic and kinetic factors on its morphology and physicochemical properties. We highlight recent contributions to developing strategies for the construction of SSC with increasing complexity and functionality that are suitable for a variety of food applications. Finally, we briefly outline our perspectives and discuss the challenges in the field.

Effect of green-lipped mussel (Perna canaliculus) supplementation on faecal microbiota, body composition and iron status markers in overweight and obese postmenopausal women: a randomised, double-blind, placebo-controlled trial

The present study aimed to determine the effect of whole meat GSM powder on gut microbiota abundance, body composition and iron status markers in healthy overweight or obese postmenopausal women. This was a 3-months trial involving forty-nine healthy postmenopausal women with body mass index (BMI) between 25 and 35 kg/m² who were randomly assigned to receive 3 g/d of either GSM powder (n 25) or placebo (n 24). The gut microbe abundance, serum iron status markers and body composition were measured at the baseline and the end of the study. The between-group comparison at the baseline showed a lower abundance of Bacteroides and Clostridium XIVa in the GSM group compared with the placebo (P = 0⋅04). At the baseline, the body fat (BF)% and gynoid fat% were higher in the GSM group compared with the placebo (P < 0⋅05). No significant changes were found in any of the outcome measures, except for ferritin levels that showed a significant reduction over time (time effect P = 0⋅01). Some trend was observed in bacteria including Bacteroides and Bifidobacterium which tended to increase in the GSM group while their abundance decreased or remained at their baseline level in the control group. Supplementation with GSM powder did not result in any significant changes in gut microbe abundance, body composition and iron markers compared with placebo. However, some commensal bacteria such as Bacteroides and Bifidobacteria tended to increase following supplementation with GSM powder. Overall, these findings can expand the knowledge surrounding the effects of whole GSM powder on these outcome measures in healthy postmenopausal women.

Folic Acid-Chitosan Oligosaccharide Conjugates Decorated Nanodiamond as Potential Carriers for the Oral Delivery of Doxorubicin

Oral administration of doxorubicin (DOX) is preferred but challenged owing to poor permeability in the gastrointestinal tract (GIT), efflux of P-glycoprotein, short residence time in the intestine, and rapid hydrolysis. Herein, folic acid-chitosan oligosaccharide conjugate (FA-COS)-modified hydroxylated nanodiamond (ND-OH) was designed to enhance the oral bioavailability of DOX. The carboxyl surface of ND was modified into hydroxyl terminal group to increase the colloidal stability of the system under different pH conditions in GIT. FA-COS modification could prolong retention time, endow the drug with sustained release properties, and actively target intestinal FA receptors. In contrast to DOX/ND-OH, the particle size of DOX/ND-OH/FA-COS increased from 189.5 ± 2.8 to 224.5 ± 1.4 nm, and the zeta potential reversed from - 9.1 ± 0.2 to 14.8 ± 0.4 mV. At 48 h, DOX/ND-OH and DOX/ND-OH/FA-COS released 69.07 ± 5.70% and 35.87 ± 5.64%, respectively. FA-COS modification effectively enhanced the cytotoxicity and intracellular uptake of ND-OH/DOX by Caco-2 cells and prolonged intestinal retention in rats. The internalization of DOX/ND-OH and DOX/ND-OH/FA-COS was mainly mediated by energy-dependent clathrin- and caveolae-mediated endocytosis pathways. Pharmacokinetic study demonstrated that the AUC_0-t of DOX/ND-OH and DOX/ND-OH/FA-COS was enhanced by 3.94- and 6.08-fold compared to DOX solution, respectively. These results illustrated that DOX/ND-OH/FA-COS could be an effective strategy to enhance the oral bioavailability of DOX.

Preparation and in vitro evaluation of hot-melt extruded pectin-based pellets containing ketoprofen for colon targeting

This work developed high drug-load pellets for colon targeting in minimal steps by coupling hot-melt extrusion (HME) with a die-surface cutting pelletizer, offering a potential continuous pellet manufacturing process. Ketoprofen (KTP) was selected as a model drug for this study due to its thermal stability and severe upper gastrointestinal side effects. Low and high methoxyl grade pectins were the enzyme-triggered release matrix, and hydroxypropyl methylcellulose (HME 4 M/HME 100LV) was used as a premature release-retarding agent. The powder X-ray diffraction technique and the differential scanning calorimetry results revealed that KTP exists in the solid-solution state within the polymeric matrix after the HME step. The scanning electron micrographs of the fabricated pellets showed a smooth surface without any cracks. The lead formulation showed the lowest premature drug release (∼13%) with an extended KTP release profile over a 24 h period in the presence and absence of the release-triggering enzyme. The lead formulation was stable for 3 months at accelerated stability conditions (40 °C/75 ± 5% RH) concerning drug content, in vitro release, and thermal characteristics. In summary, coupling HME and pelletization processes could be a promising technology for developing colon-targeted drug delivery systems.

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.

Colonic Delivery of Nutrients for Sustained and Prolonged Release of Gut Peptides: A Novel Strategy for Appetite Management

Obesity is one of the major global threats to human health and risk factors for cardiometabolic diseases and certain cancers. Glucagon-like peptide-1 (GLP-1) plays a major role in appetite and glucose homeostasis and recently the USFDA approved GLP-1 agonists for the treatment of obesity and type 2 diabetes. GLP-1 is secreted from enteroendocrine L-cells in the distal part of the gastrointestinal (GI) tract in response to nutrient ingestion. Endogenously released GLP-1 has a very short half-life of <2 min and most of the nutrients are absorbed before reaching the distal GI tract and colon, which hinders the use of nutritional compounds for appetite regulation. The review article focuses on nutrients that endogenously stimulate GLP-1 and peptide YY (PYY) secretion via their receptors in order to decrease appetite as preventive action. In addition, various delivery technologies such as pH-sensitive, mucoadhesive, time-dependent, and enzyme-sensitive systems for colonic targeting of nutrients delivery are described. Sustained colonic delivery of nutritional compounds could be one of the most promising approaches to prevent obesity and associated metabolic diseases by, e.g., sustained GLP-1 release.

A magnetic antibody-conjugated nano-system for selective delivery of Ca(OH)2 and taxotere in ovarian cancer cells

An efficient strategy for cancer therapy is presented, in which a tumor mass is initially pretreated with calcium hydroxide, then treated with Taxotere (TXT). In this regard, an advanced delivery system based on iron oxide nanoparticles has been designed. The surface of nanoparticles was functionalized with sortilin (SORT-1, a human IgG1 monoclonal antibody) that specifically encodes caov-4 ovarian cancerous cells. Plasmonic heating of the incorporated gold nanoparticles in polyvinyl alcohol (PVA) has been exploited to control the release process of TXT. The in vitro, ex vivo and in vivo experiments have exhibited high efficacy of a seven-day pretreatment by Ca(OH)₂ plus 14 days treatment program by Ca(OH)₂@Fe₃O₄/PVA/Au-SORT nano-therapeutics, where more penetration ratio resulted in tumor growth inhibition by ca. 78.3%. As a result, due to showing high values of the anti-tumor properties and biosafety, the presented pretreatment strategy is suggested for more effective treatment on the aged tumors.

A magnetic drug delivery system containing polyvinyl alcohol, gold nanoparticles, and sortilin antibody followed by the plasmonic photothermal heating strategy for the controlled drug release is proposed, with use in ovarian cancer demonstrated.

Multiparticulate Systems of Meloxicam for Colonic Administration in Cancer or Autoimmune Diseases

The aim of this research is the development of new colonic release systems of meloxicam (MLX) a non-steroidal anti-inflammatory drug (NSAIDs) with pH and time-dependent vehicles for cancer or autoimmune diseases. The colon has a higher pH than the rest of the gastrointestinal tract (GIT) and this can be used as a modified release strategy. Eudragit^® polymers are the most widely used synthetic products in the design of colonic release formulations because they might offer mucoadhesiveness and pH-dependent release. Colonic delivery systems produced with pH-dependent and permeable polymers (FS-30D) or with pH-independent and low permeability polymers (NM-30D), must dissolve at a pH range of 6.0–7.0 to delay the release of the drug and prevent degradation in the GIT, before reaching the colon. The conditions prepared to simulate a gastrointestinal transit showed the CNM multiparticulate system, composed of Eudragit^® NM and cellulose, as the best release option for MLX with a more sustained release with respect to the other formulations. CNM formulation followed Higuchi and First-order release kinetics, thus MLX release was controlled by a combination of diffusion and polymers swelling/eroding processes.

Role of Polysaccharides Mimetic Components in Targeted Cancer Treatment

Organic or inorganic compounds are synthesized or formulated in a manner that they completely show their therapeutic actions like as a natural polysaccharide in the body. Polysaccharides, the major type of natural polymers, are efficiently biologically active, non-toxic, hydrophilic, and biodegradable and show various properties. In this manuscript, the main focus is on delivering anticancer drugs with the help of mimetic components of polysaccharides. All data collected for this manuscript was from PubMed, Elsevier, Taylor, and Francis Bentham science journals. Most chemotherapeutics are therapeutically toxin to the human body, have a narrow therapeutic index, sluggish pharmaceutical delivery mechanisms, and are poorly soluble in water. The use of mimetic components of polysaccharides leads to the enhancement of the solubility of drugs in the biological environment. The manuscript summarizes the use of mimetic components of polysaccharides along with anticancer agents which are capable to inhibit the growth of cancerous cells in the body which shows lesser adverse effects in the biological system compared to other therapies.

Optimization study of combined enteric and time-dependent polymethacrylates as a coating for colon targeted delivery of 5-ASA pellets in rats with ulcerative colitis

Formulation design for colon-specific delivery of 5-aminosalicylic acid (5-ASA) could bring some therapeutic benefits in the treatment of ulcerative colitis (UC). In the current study, a 3² full factorial design was used to predict optimum coating composed of two enteric (poly methacrylic acid, methyl methacrylates 1:2 and 1:1) and time-dependent (poly ethyl acrylate, methyl methacrylate, trimethylammonio ethyl methacrylate chloride 1:2:0.1) polymethacrylates for colon-specific delivery of 5-ASA pellets. A unique coating composition and coating level predicted by the model was applied onto either inulin-free 5-ASA pellets or inulin-bearing 5-ASA pellets and the coated pellets were examined by dissolution test in-vitro. The coated pellets were also tested in a rat model of UC and compared with the a commercially available colonic delivery system of 5-ASA. The ratio of the two enteric polymethacrylates and time-dependet polymethacrylate of 16:64:20 w/w at a coating level of 15% was discovered as the optimum coating for delivery of 5-ASA pellets to the colon. In general, the coated pellets offered a better therapeutic outcome compared to commercially available colonic delivery system of 5-ASA and uncoated pellets in terms of colitis activity index and the colon's tissue enzymes of MDA and GSH. It seems that the coating composed of enteric and pH-dependent polymethacrylates could tune up the rate of drug release from 5-ASA-coated pellets and trigger drug release based on pH and time.

Chitosan-Based Biocompatible Copolymers for Thermoresponsive Drug Delivery Systems: On the Development of a Standardization System

Chitosan is a natural polysaccharide that is considered to be biocompatible, biodegradable and non-toxic. The polymer has been used in drug delivery applications for its positive charge, which allows for adhesion with and recognition of biological tissues via non-covalent interactions. In recent times, chitosan has been used for the preparation of graft copolymers with thermoresponsive polymers such as poly-N-vinylcaprolactam (PNVCL) and poly-N-isopropylamide (PNIPAM), allowing the combination of the biodegradability of the natural polymer with the ability to respond to changes in temperature. Due to the growing interest in the utilization of thermoresponsive polymers in the biological context, it is necessary to increase the knowledge of the key principles of thermoresponsivity in order to obtain comparable results between different studies or applications. In the present review, we provide an overview of the basic principles of thermoresponsivity, as well as a description of the main polysaccharides and thermoresponsive materials, with a special focus on chitosan and poly-N-Vinyl caprolactam (PNVCL) and their biomedical applications.

A Study of Compressibility, Compactability and Mucoadhesivity of Tableting Materials for Matrix Systems Based on Chitosan

The objective of the present research is to evaluate directly compressible chitosan-based tableting materials for the formulation of mucoadhesive matrix tablets intended for targeted drug release to distal segments of the GIT. The influence of sodium alginate, hypromellose, and silicified microcrystalline cellulose (P90) on compressibility, compactability and lubricant sensitivity ratio was tested. Furthermore, the rheological properties of the hydrated surface layer of the matrix tablets and the mucoadhesion to a mucin substrate were analysed. Compressibility was evaluated using the energy profile of the compression process, compactability by means of the tensile strength of tablets, and lubricant sensitivity ratio was calculated to assess the sensitivity to lubricant. Addition of P90 to chitosan improved compressibility, which is demonstrated by the increase in the energy of plastic deformation and the higher tensile strength of tablets. P90 also significantly reduced the high lubricant sensitivity of chitosan. Presence of retarding components led to a decrease in Emax. All tested matrix tablets revealed a good mucoadhesion without a negative effect of P90 content. The viscosity of a gel layer on the surface of matrix tablets containing hypromellose was higher compared to those with sodium alginate. This was not reflected in the adhesive strength of the tablets. The formulated tableting materials combining chitosan and P90 are a suitable matrix for incorporation of an active ingredient, whose delayed release in the intestine can be achieved by the functionality of the chitosan-sodium alginate complex.

Network pharmacology and experimental investigation of Rhizoma polygonati extract targeted kinase with herbzyme activity for potent drug delivery

Rhizoma polygonati (Huangjing, RP) has been used for a long history with many chemical components in inducing anti-cancer, anti-aging, anti-diabetes, anti-fatigue, and more prevention of diseases or acts as nutrition sources in food. Here we investigated RP extract combination with kinase inhibitors in anti-cell growth and blockade in pathways targeting kinases. Experimental investigation and network pharmacology analysis were applied to test the potent kinase-mediated signaling. Herbzyme activity was determined by substrate with optical density measurement. Extract of processed RP inhibits cell growth in a much greater manner than alone when applied in combination with inhibitors of mTOR or EGFR. Moreover, processing methods of RP from Mount Tai (RP-Mount Tai) play essential roles in herbzyme activity of phosphatase suggesting the interface is also essential, in addition to the chemical component. The network pharmacology analysis showed the chemical component and target networks involving AKT and mTOR, which is consistent with experimental validation. Finally, EGFR inhibitor could be associated with nano-extract of RP-Mount Tai but not significantly affects the phosphatase herbzyme activity in vitro. Thus the processed extract of RP-Mount Tai may play a dual role in the inhibition of cell proliferation signaling by both chemical component and nanoscale herbzyme of phosphatase activity to inhibit kinases including mTOR/AKT in potent drug delivery of kinase inhibitors.

Methotrexate-Loaded Gelatin and Polyvinyl Alcohol (Gel/PVA) Hydrogel as a pH-Sensitive Matrix

The aim was to formulate and evaluate Gel/PVA hydrogels as a pH-sensitive matrix to deliver methotrexate (MTX) to colon. The primed Gel/PVA hydrogels were subjected to evaluation for swelling behavior, diffusion coefficient, sol-gel characteristic and porosity using an acidic (pH 1.2) and phosphate buffer (PBS) (pH 6.8 & pH 7.4) media. Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) were performed to evaluate the chemical compatibility of the Gel/PVA hydrogel. The shape alteration and release of Gel/PVA hydrogel was conducted at pH 1.2, pH 6.8 and pH 7.4. The drug release kinetic mechanism was determined using various kinetic equations. The physicochemical evaluation tests and drug release profile results were found to be significant (p < 0.01). However, it was dependent on the polymers' concentration, the pH of the release media and the amount of the cross-linking agent. Hydrogels containing the maximum amount of gel showed a dynamic equilibrium of 10.09 ± 0.18 and drug release of 93.75 ± 0.13% at pH 1.2. The kinetic models showed the release of MTX from the Gel/PVA hydrogel was non-Fickian. The results confirmed that the newly formed Gel/PVA hydrogels are potential drug delivery systems for a controlled delivery of MTX to the colon.

Guar gum-derived galactomannan induces inflammatory responses and increased energy expenditure in the intestine

Guar gum-derived galactomannan (GGGM) has been widely used in the food industry for a long time and its adverse impacts have been scarcely reported. Galactomannan is considered to have a structure similar to the surface components of certain pathogens, and the present study was thus conducted to investigate if oral administration of GGGM could cause physiological effects that were hypothesized to be related to intestinal inflammatory responses. The results showed that oral administration of GGGM resulted in compromises on growth performance, an increase of the relative weight of spleen and epididymal fat, and an elevation of the α1-acid glycoprotein content in both serum and livers of mice. With regard to energy metabolism-related indices, the activities of intestinal lactic dehydrogenase and succinic dehydrogenase were all increased by the GGGM treatment in both in vivo and in vitro experiments, the latter of which also showed an elevation in the consumption of reducing sugar by intestinal epithelial cells along with a reduced viability of these cells in response to the GGGM treatment. Notably, the GGGM treatment triggered intestinal inflammatory responses that were evidenced by the increased expression of intestinal inflammatory cytokines such as TNF-α and IL-6 both in vivo and in vitro, which were at least partially responsible for the increased energy expenditure in the intestine and the retardation of growth. The results of this study could expand our knowledge of GGGM administration and provide integrated insights into the consumption of GGGM-containing foods.

Impact of Glucosamine Supplementation on Gut Health

Glucosamine (GLU) is a natural compound found in cartilage, and supplementation with glucosamine has been shown to improve joint heath and has been linked to reduced mortality rates. GLU is poorly absorbed and may exhibit functional properties in the gut. The purpose of this study was to examine the impact of glucosamine on gastrointestinal function as well as changes in fecal microbiota and metabolome. Healthy males (n = 6) and females (n = 5) (33.4 ± 7.7 years, 174.1 ± 12.0 cm, 76.5 ± 12.9 kg, 25.2 ± 3.1 kg/m2, n = 11) completed two supplementation protocols that each spanned three weeks separated by a washout period that lasted two weeks. In a randomized, double-blind, placebo-controlled, crossover fashion, participants ingested a daily dose of GLU hydrochloride (3000 mg GlucosaGreen®, TSI Group Ltd., Missoula, MT, USA) or maltodextrin placebo. Study participants completed bowel habit and gastrointestinal symptoms questionnaires in addition to providing a stool sample that was analyzed for fecal microbiota and metabolome at baseline and after the completion of each supplementation period. GLU significantly reduced stomach bloating and showed a trend towards reducing constipation and hard stools. Phylogenetic diversity (Faith's PD) and proportions of Pseudomonadaceae, Peptococcaceae, and Bacillaceae were significantly reduced following GLU consumption. GLU supplementation significantly reduced individual, total branched-chain, and total amino acid excretion, with no glucosamine being detected in any of the fecal samples. GLU had no effect on fecal short-chain fatty acids levels. GLU supplementation provided functional gut health benefits and induced fecal microbiota and metabolome changes.

Anti-inflammatory effects of acacia and guar gum in 5-amino salicylic acid formulations in experimental colitis

Findings from recent studies revealed a significant anti-inflammatory effect of polysaccharide-based excipients when formulated with classical drugs in experimental inflammatory bowel disease models. In this study, acacia and guar gum were investigated beyond their typical functionality for a possible additive anti-inflammatory effect when administered with 5-amino salicylic acid (5ASA) in murine experimental colitis. Anti-inflammatory effects of acacia and guar gum-based aqueous suspensions of 5ASA were evaluated in a murine experimental colitis. Acacia or guar gum (30 or 300 mg/kg) were administered via rectal administration alone or in combination with 5ASA (30 mg/kg). Disease activity, myeloperoxidase activity (MPO) and intratissue concentrations of various cytokines were assessed. Both acacia and guar gum separately showed significant effects in reducing the inflammatory markers in murine colitis model in vivo. When combined with the anti-inflammatory drug 5ASA, acacia showed a stronger therapeutic effect than guar gum, especially at the higher dose of acacia (300 mg/kg) which significantly reduced the inflammation in vivo compared to 5ASA alone (MPO, 5ASA: 5743 ± 1334, 5ASA + 30 mg/kg acacia: 3762 ± 2342; 5ASA + 30 mg/kg guar gum: 7373 ± 2115, 5ASA + 300 mg/kg acacia: 3131 ± 1012, 5ASA + 300 mg/kg guar gum: 6358 ± 2379; all U/g tissue). Acacia and guar gum separately showed significant anti-inflammatory effects in murine colitis, and furthermore, high dose acacia led to an additional therapeutic benefit when co-administered with 5ASA. These results indicate that further investigations are surely warranted in the search of better colitis therapy.

Dual pH-/thermo-responsive chitosan-based hydrogels prepared using "click" chemistry for colon-targeted drug delivery applications

A dual pH-/thermo-responsive hydrogel was designed based on a polyelectrolyte complex of polyacrylic acid (PAA) and norbornene-functionalized chitosan (CsNb), which was synergized with chemical crosslinking using bistetrazine-poly(N-isopropyl acrylamide) (bisTz-PNIPAM). The thermo-responsive polymeric crosslinker, bisTz-PNIPAM, was synthesized via reversible addition-fragmentation transfer polymerization of NIPAM. FTIR, XRD, rheological and morphological analyses demonstrated the successful formation of the polyelectrolyte network. The highly porous structure generated through the in-situ "click" reaction between Tz and Nb resulted in a higher drug loading (29.35 %). The hydrogel (COOH/NH₂ mole ratio of 3:1) exhibited limited drug release (8.5 %) of 5-ASA at a pH of 2.2, but it provided an almost complete release (92 %) at pH 7.4 and 37 °C within 48 h due to the pH responsiveness of PAA, hydrogel porosity, and shrinkage behavior of PNIPAM. The hydrogels were biodegradable and non-toxic against human fibroblast cells, suggesting their considerable potential for a colon-targeted drug delivery system.

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.

Preparation, development and characterization of Leucaena leucocephala galactomannan (LLG) conjugated sinapic acid: A potential colon targeted prodrug

Sinapic acid (SA), a widely prevalent hydroxycinnamic acid, possess numerous biological activities owing to its antioxidant property. The present study was aimed to prepare colon targeted polysaccharidic/polymeric ester prodrug of SA (a microbially triggered system) using Leucaena leucocephala galactomannan (LLG) as a polysaccharidic carrier. The polymeric conjugates of SA-LLG were found to exhibit an increase in % yield and DS with increase in amount of SA and volume of thionyl chloride. The degree of depolymerization of SA-LLG prodrug batches were evaluated using optimized concentration of galactomannase. The SA-LLG prodrug was characterized employing UV and FTIR spectroscopy, ¹H NMR and XRD. In vitro release study of the optimized prodrug batch (SL10) suggested stable nature of SA-LLG conjugate under acidic (pH 1.2) and alkaline conditions (pH 6.8). The treatment of prodrug with galactomannase (15 mg/mL) followed by esterase (10 U/mL) enzyme released approximately 81% of SA after 24 h. The cell viability results revealed that free SA and SA-LLG were found to have similar antiproliferative potential against human colon cancer cell lines (HCT-116 cells). Our investigation revealed that polysaccharidic prodrug, SA-LLG, has the potential for colon targeting of SA and thus can be employed for the treatment of Inflammatory Bowel Diseases (IBDs).

Application of inulin/Eudragit RS in 5-ASA pellet coating with tuned, sustained-release feature in an animal model of ulcerative colitis

A tunable release of 5-aminosalicylic acid (5-ASA) could bring therapeutic benefits in the treatment of inflammatory bowel disease (IBD). A 3² factorial design was used to achieve a tuned delivery of 5-ASA pellets in the small and large intestine using a coating composed of inulin/Eudragit RS (RS). The ratio of inulin/RS and coating level were independent variables while the dependent variables were the percent of drug release at pH 1.2 in 2 h and total release of drug in 10 h at pH 6.8. 5-ASA release from pellets was examined at different pH levels and the therapeutic efficacy of the optimum pellets was compared to 5-ASA pellets of Pentasa in rats with ulcerative colitis. The inulin/RS of 18/82 at a coating level of 16% was found to be the optimum for delivery of the drug to the small and large intestine. The coated pellets offered a superior therapeutic outcome compared to uncoated pellets and Pentasa in terms of colitis activity index (CAI), and the colon's tissue enzymes of GSH and MDA. The optimum coating composed of inulin and RS could offer a tuned sustained release of 5-ASA throughout the small and large intestine with the sensitivity of drug release to microbial degradation.

Drug Disposition in the Lower Gastrointestinal Tract: Targeting and Monitoring

The increasing prevalence of colonic diseases calls for a better understanding of the various colonic drug absorption barriers of colon-targeted formulations, and for reliable in vitro tools that accurately predict local drug disposition. In vivo relevant incubation conditions have been shown to better capture the composition of the limited colonic fluid and have resulted in relevant degradation and dissolution kinetics of drugs and formulations. Furthermore, drug hurdles such as efflux transporters and metabolising enzymes, and the presence of mucus and microbiome are slowly integrated into drug stability- and permeation assays. Traditionally, the well characterized Caco-2 cell line and the Ussing chamber technique are used to assess the absorption characteristics of small drug molecules. Recently, various stem cell-derived intestinal systems have emerged, closely mimicking epithelial physiology. Models that can assess microbiome-mediated drug metabolism or enable coculturing of gut microbiome with epithelial cells are also increasingly explored. Here we provide a comprehensive overview of the colonic physiology in relation to drug absorption, and review colon-targeting formulation strategies and in vitro tools to characterize colonic drug disposition.

Polysaccharides; Classification, Chemical Properties, and Future Perspective Applications in Fields of Pharmacology and Biological Medicine (A Review of Current Applications and Upcoming Potentialities)

Polysaccharides are essential macromolecules which almost exist in all living forms, and have important biological functions, they are getting more attention because they exhibit a wide range of biological and pharmacological activities, such as anti-tumour, immunomodulatory, antimicrobial, antioxidant, anticoagulant, antidiabetic, antiviral, and hypoglycemia activities, making them one of the most promising candidates in biomedical and pharmaceutical fields. Polysaccharides can be obtained from many different sources, such as plants, microorganisms, algae, and animals. Due to their physicochemical properties, they are susceptible to physical and chemical modifications leading to enhanced properties, which is the basic concept for their diverse applications in biomedical and pharmaceutical fields. In this review, we will give insight into the most recent updated applications of polysaccharides and their potentialities as alternatives for traditional and conventional therapies. Challenges and limitations for polysaccharides in pharmaceutical utilities are discussed as well.

Recent Advances in Injectable Hydrogels for Controlled and Local Drug Delivery

Injectable hydrogels have received considerable interest in the biomedical field due to their potential applications in minimally invasive local drug delivery, more precise implantation, and site-specific drug delivery into poorly reachable tissue sites and into interface tissues, where wound healing takes a long time. Injectable hydrogels, such as in situ forming and/or shear-thinning hydrogels, can be generated using chemically and/or physically crosslinked hydrogels. Yet, for controlled and local drug delivery applications, the ideal injectable hydrogel should be able to provide controlled and sustained release of drug molecules to the target site when needed and should limit nonspecific drug molecule distribution in healthy tissues. Thus, such hydrogels should sense the environmental changes that arise in disease states and be able to release the optimal amount of drug over the necessary time period to the target region. To address this, researchers have designed stimuli-responsive injectable hydrogels. Stimuli-responsive hydrogels change their shape or volume when they sense environmental stimuli, e.g., pH, temperature, light, electrical signals, or enzymatic changes, and deliver an optimal concentration of drugs to the target site without affecting healthy tissues.

Macrophages-targeting mannosylated nanoparticles based on inulin for the treatment of inflammatory bowel disease (IBD)

In the present experimental series, we have developed a novel nanocomposite to target activated macrophages in the colon with real time imaging and therapeutic capabilities. This binary nanocomposite was formed by the covalent conjugation of mannosylated NPs (Man-NPs) with carbon dots (CDs). Man-NPs were prepared using a self-assembly method based on mannosylated decamethylenediamine-grafted carboxymethyl inulin amphiphilic acid. While, the CDs were synthesized using a simple bottom-up process using citric acid monohydrate and diethylenetriamine, which were tightly bonded to the Man-NPs surface by carbodimide coupling. The resulting nanocomposite had a uniform size of 241.3 nm with a negative charge and a high drug casing density of 25.54 wt% and blue self-fluorescence were emitted. Whereas, in vitro observation of cellular uptake indicated the greater nanocomposite uptake in inflamed macrophage as compared to the untreated macrophage and mannose receptor-negative cell lines, 4T1 respectively. However, in vivo bio distribution exhibited a large number (60%) of CDs/Man-NPs nanocomposite accumulated in the inflamed colon of colitis mice. It should be noted that the novel nanocomposite, as macrophage-targeted drug delivery, could have promise for the treatment of inflammatory bowel disease (IBD).

Fabrication of curcumin-zein-ethyl cellulose composite nanoparticles using antisolvent co-precipitation method

The stable colloidal nano-dispersion of curcumin (CU) loaded zein-ethyl cellulose (ZN-EC) as three hydrophobic agent in water was prepared using two step antisolvent co-precipitation method. The EC coated NPs were prepared by adding EC in ethyl acetate to the ZN-CU NPs at a concentration ratio of 1: 3.5 w/v. The prepared colloidal suspension of ZN-EC showed high physical stability during storage time. The particle diameters and zeta potential values of ZN-CU and ZN-CU-EC colloidal suspensions were 140 ± 12 nm, 38 ± 2 mV and 179 ± 12 nm, 12 ± 2 mV, respectively. Based on Scanning electron microscopy (SEM) images, participation of EC on the surface of ZN-CU particles could reduce the sticky appearance of particles. Encapsulation efficiency of CU in NPs did not improve after precipitation of EC, but the stability of NPs against pH changes, increased and release rate of CU from NPs at different pH values (3-8) were significantly reduced in comparison of ZN-CU NPs. The EC coated NPs showed the excessive protection for CU antioxidant activity during storage. In conclusion, the prepared NPs, with high physical stability, have good potential for encapsulation and delivery of CU to colon region.

Natural proteins and polysaccharides in the development of micro/nano delivery systems for the treatment of inflammatory bowel disease

Treatments for inflammatory bowel disease (IBD) are typically immunosuppressive. Despite a range of treatment options, limited efficacy, systemic toxicities like bone marrow suppression, infections and malignancy are their serious setbacks. There exists an unmet medical need for novel therapeutic agents without safety concerns resulting from chronic, systemic immunosuppression. Of late, several natural agents with better therapeutic potential have been reported. It is very likely that restricting the release of the active molecules to the intestine would further improve their clinical efficacy and safety. To this end, novel polymer-based micro/nano formulations protect the drug from gastric environment and slowly release the drug in the colon. However, cost and side-effects associated to synthetic polymers have led to the development of biocompatible, economic and pharmaceutically well-accepted biomacromolecules in exploring their potential in IBD. Since last few years, biological proteins, polysaccharides and their combinations have shown great efficacy in colitis induced animal models. In this review, micro/nano formulations developed using biomacromolecules like chitosan, zein, pectin, casein, alginate, dextran, glucomannan and hyaluronic acid have been reviewed focusing on their potential in protecting active cargo, avoiding premature release, distal colon targeting along with their impact on reshaping the altered gut microbiota and how it can ameliorate the colitis conditions.

Quantification of Monomer Units in Insoluble Polymeric Active Pharmaceutical Ingredients Using Solid-State NMR Spectroscopy I: Patiromer

Although extensive precautions are taken to limit batch-to-batch variation in pharmaceutical manufacturing, differences between lots may still exist, particularly in complex formulations. When polymerization is used in the production process, the potential for varying chain lengths and incorporation of different monomers increases the likelihood of batch-to-batch variation. This poses a significant challenge for demonstrating active pharmaceutical ingredient (API) sameness between the innovator and generic drug under development. Therefore, the ability to accurately analyze and quantify the relative amounts of active ingredients present in a formulated product is critically important. Solid-state nuclear magnetic resonance (SSNMR) spectroscopy was used to identify, quantify, and compare the relative amounts of the three polymer groups in the amorphous block copolymer drug, patiromer (Veltassa^®). Techniques such as cross polarization (CP) and magic angle spinning were used to quantify each polymer group while the importance of understanding CP dynamics to obtain quantitative data was also addressed. It was found that the magnetization transfer rate and chemical shift anisotropy for different functional groups present in patiromer play a large role when optimizing parameters for spectral acquisition. Once accounted for, the average patiromer lot contained 90.9%, 7.6%, and 1.5% carboxylate, aromatic, and aliphatic blocks, respectively, with little lot-to-lot variation between different dosage strengths and expiration dates. SSNMR proved to be a sensitive analytical technique for evaluating and quantifying different monomer groups present in patiromer. This procedure may serve as a guide for similar quantitation studies on complex drug products and for demonstrating API sameness during generic drug development.

Orally delivered targeted nanotherapeutics for the treatment of colorectal cancer

INTRODUCTION

Colorectal cancer (CRC), the third-most common malignancy, has high morbidity and mortality. Oral nanotherapeutics have emerged as a promising strategy to improve the therapeutic outcomes and alleviate the adverse effects of drugs in CRC treatment.

AREAS COVERED

In this review, we introduce the beneficial features of oral drug administration for CRC therapy, and further address the three basic elements of nanotherapeutics, namely, therapeutic agents, carrier materials, and targeting ligands. In addition, we also discuss the potentials of the new emerging technologies (e.g., immunotherapy, gene editing and microbiota manipulation) in the treatment of CRC.

EXPERT OPINION

Orally delivered targeted nanotherapeutics represent a promising strategy toward the efficient treatment of CRC. Although the current oral nanotherapeutics exert better therapeutic outcomes than the traditional drug formulations, their application has been restricted by drug resistance, tumor metastasis, and biosafety. Therefore, it is necessary to exploit new nanotherapeutics in the aspects of their three basic elements, and combine the new emerging technologies to those nanotherapeutics for CRC treatment.

Reactive oxygen species responsive nanoplatforms as smart drug delivery systems for gastrointestinal tract targeting

The pharmacological therapy for gastrointestinal (GI) diseases, such as inflammatory bowel diseases, continues to present challenges in targeting efficacy. The need for maximal local drug exposure at the inflamed regions of the GI tract has led research to focus on a disease-targeted drug delivery approach. Smart nanomaterials responsive to the reactive oxygen species (ROS) concentrated in the inflamed areas, can be formulated into nanoplatforms to selectively release the active compounds, avoiding unspecific drug delivery to healthy tissues and limiting systemic absorption. Recent developments of ROS-responsive nanoplatforms include combination with other materials to obtain multi-responsive systems and modifications/derivatization to increase the interactions with biological tissues, cell uptake and targeting. This review describes the applications of ROS-responsive nanosystems for on-demand drug delivery to the GI tract.

Functional polysaccharides of carob fruit: a review

Polysaccharides in carob fruit, including carob bean gum (also known as carob gum, locust bean gum) and carob fiber, are widely used in industries such as food, pharmaceuticals, paper, textile, oil well drilling and cosmetics. Carob bean gum is a galactomannan obtained from the seed endosperm of carob tree and the fiber is obtained by removing most of soluble carbohydrates in carob pulp by water extraction. Both the gum and fiber are beneficial to health for many diseases such as diabetes, bowel movements, heart disease and colon cancer. This article reviewed the composition, properties, food applications and health benefits of polysaccharides from carob fruit.

Polymeric Microsphere Formulation for Colon Targeted Delivery of 5-Fluorouracil Using Biocompatible Natural Gum Katira

Controlled release delivery system of chemotherapeutic agents at the site of colon endorses modern drug-entrapped delivery tools, which release the entrappedagents at a controlled rate for anextended period providing patient compliance and additional protection from the degradinggastric environment. Thus, the present study was aimed to develop and optimize a novel polymeric microsphere of 5-fluorouracil (5-FU) using natural gum katira to obtain an optimal therapeutic response at the colon. Due course of experimentation, in-vivo safety profile of the gum katira in an animal model was established. Modified solvent extraction/evaporation technique wasemployed to encapsulate 5-FU in the natural polymeric microsphere and was characterized using in-vitro studies to investigate particle size, morphology, encapsulation efficiency and release of the drug from developed formulation. Formulated and optimized polymeric microsphere of 5-FU using gum katira polymer own optimal physicochemical characteristics with a fine spherical particle with size ranged from 210.37±7.50 to 314.45±7.80 µm.Targeted microsphere exhibited good cytotoxicity and also has high drug entrapment efficiency, and satisfactory release pattern of the drug within a time frame of 12 h. Finally, we foresee that the optimized polymeric gum katiramicrosphere of 5-FU could be a promising micro-carrier for efficient colon drug targeting delivery tool with improved chemotherapeutic efficacy against colon cancer.

Novel drug delivery systems of Chinese medicine for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory disease that comprises ulcerative colitis (UC) and Crohn's disease (CD). IBD involves the ileum, rectum, and colon, and common clinical manifestations of IBD are diarrhea, abdominal pain, and even bloody stools. Currently, non-steroidal anti-inflammatory drugs, glucocorticoids, and immunosuppressive agents are used for the treatment of IBD, while their clinical application is severely limited due to unwanted side effects. Chinese medicine (CM) is appealing more and more attention and investigation for the treatment of IBD owing to the potent anti-inflammation pharmacological efficacy and high acceptance by patients. In recent years, novel drug delivery systems are introduced apace to encapsulate CM and many CM-derived active constituents in order to improve solubility, stability and targeting ability. In this review, advanced drug delivery systems developed in the past and present to deliver CM for the treatment of IBD are summarized and future directions are discussed.

MicroRNA-31 Reduces Inflammatory Signaling and Promotes Regeneration in Colon Epithelium, and Delivery of Mimics in Microspheres Reduces Colitis in Mice

BACKGROUND & AIMS

Levels of microRNA 31 (MIR31) are increased in intestinal tissues from patients with inflammatory bowel diseases and colitis-associated neoplasias. We investigated the effects of this microRNA on intestinal inflammation by studying mice with colitis.

METHODS

We obtained colon biopsy samples from 82 patients with ulcerative colitis (UC), 79 patients with Crohn's disease (CD), and 34 healthy individuals (controls) at Shanghai Tenth People's Hospital. MIR31- knockout mice and mice with conditional disruption of Mir31 specifically in the intestinal epithelium (MIR31 conditional knockouts) were given dextran sulfate sodium (DSS) or 2,4,6-trinitrobenzene sulfonic acid (TNBS) to induce colitis. We performed chromatin immunoprecipitation and luciferase assays to study proteins that regulate expression of MIR31, including STAT3 and p65, in LOVO colorectal cancer cells and organoids derived from mouse colon cells. Partially hydrolyzed alpha-lactalbumin was used to generate peptosome nanoparticles, and MIR31 mimics were loaded onto their surface using electrostatic adsorption. Peptosome-MIR31 mimic particles were encapsulated into oxidized konjac glucomannan (OKGM) microspheres, which were administered by enema into the large intestines of mice with DSS-induced colitis. Intestinal tissues were collected and analyzed by histology and immunohistochemistry.

RESULTS

Levels of MIR31 were increased in inflamed mucosa from patients with CD or UC, and from mice with colitis, compared with controls. STAT3 and nuclear factor-κB activated transcription of MIR31 in colorectal cancer cells and organoids in response to tumor necrosis factor and interleukin (IL)6. MIR31-knockout and conditional-knockout mice developed more severe colitis in response to DSS and TNBS, with increased immune responses, compared with control mice. MIR31 bound to 3' untranslated regions of Il17ra and Il7r messenger RNAs (RNAs) (which encode receptors for the inflammatory cytokines IL17 and IL7) and Il6st mRNA (which encodes GP130, a cytokine signaling protein). These mRNAs and proteins were greater in MIR31-knockout mice with colitis, compared with control mice; MIR31 and MIR31 mimics inhibited their expression. MIR31 also promoted epithelial regeneration by regulating the WNT and Hippo signaling pathways. OKGM peptosome-MIR31 mimic microspheres localized to colonic epithelial cells in mice with colitis; they reduced the inflammatory response, increased body weight and colon length, and promoted epithelial cell proliferation.

CONCLUSIONS

MIR31, increased in colon tissues from patients with CD or UC, reduces the inflammatory response in colon epithelium of mice by preventing expression of inflammatory cytokine receptors (Il7R and Il17RA) and signaling proteins (GP130). MIR31 also regulates the WNT and Hippo signaling pathways to promote epithelial regeneration following injury. OKGM peptosome-MIR31 microspheres localize to the colon epithelium of mice to reduce features of colitis. Transcript Profiling: GSE123556.