pH-Responsive Alginate-Based Microparticles for Colon-Targeted Delivery of Pure Cyclosporine A Crystals to Treat Ulcerative Colitis

pH-Dependent Drug Delivery Systems for Ulcerative Colitis Treatment

Inflammatory bowel diseases (IBDs), such as ulcerative colitis (UC) or Crohn's disease, are becoming a growing global problem due to the limitations of current treatments, which fail to address the needs of patients effectively. UC is characterized by the widespread inflammation of the mucosal lining, affecting both the rectum and the entire length of the colon. Over the past forty years, traditional treatments for IBDs have primarily relied on anti-inflammatory drugs and immunosuppressive medications. Treatment could be more effective if drugs could be specifically targeted to act directly on the colon. Conventional drug delivery systems for IBDs encounter numerous challenges on their way to the colon, such as physiological barriers and disease severity. To address these issues, pH-dependent carriers have emerged as a promising advancement, offering a more effective and tolerable treatment for UC. These carriers enable localized, targeted action, reducing side effects and preventing the premature clearance of drugs from inflamed colon tissues. pH-responsive systems are a leading approach for targeted drug release in colitis treatment as they take advantage of the varying pH levels throughout the gastrointestinal tract (GIT). By incorporating pH-sensitive polymers, they ensure drug protection and controlled release in the lower GIT. This review will discuss the advantages and limitations of pH-dependent drug delivery systems for colon-targeted drug delivery.

Advanced polymeric systems for colon drug delivery: from experimental models to market applications

In recent years, nano and micro drug delivery systems targeting the colon have gained more attention due to increasing interest in treating colon diseases such as colorectal cancer and inflammatory bowel disease, i.e., Crohn's disease and ulcerative colitis. Usually, nanocarriers are exploited for their enhanced permeability properties, allowing higher penetration effects and bioavailability, while microcarriers are primarily used for localized and sustained release. In bowel diseases, carriers must go into a delicate environment with a strict balance of gut bacteria (e.g., colon), and natural or biodegradable polymers capable of ensuring lower toxicity are preferred. However, these systems are primarily delivered orally, so the carrier must go through the whole gastrointestinal tract, where it encounters significant pH fluctuations, different mucus layers, several enzymes, and a long transit time. For this reason, various approaches have been explored and evaluated, especially using pH-responsive and time-dependent systems. This review provides an overview of the contemporary methodologies employed in orally administered nano- and microparticles for colon delivery, encompassing both in vivo and in vitro investigations. It evaluates their strengths, weaknesses, constraints, and potential enhancements, leveraging mathematical and microfluidic models. Furthermore, it focuses explicitly on systems that have already reached the market and are presently employed in treating severe colon diseases.

Evaluating the efficacy of nano-cyclosporine A in mice model of ulcerative colitis: a meta-analysis

Cyclosporine A is an immunosuppressive drug used in clinics to treat steroid-refractory ulcerative colitis (UC). However, due to its side effects, researchers are evaluating novel drug delivery-based treatment options. Nanoparticles-based cyclosporine (Nano-CSA) offers a promising option for the treatment of UC, and various in vivo studies on animals have been conducted. This meta-analysis was performed to clarify the effects of using Nano-CSA based formulations in the mouse UC model. A systemic literature search was conducted on five different electronic databases (ScienceDirect, PubMed, Embase, PMC, and Cochrane) to search studies conducted between the timeline of 2016 and 2024. The search terms include "nanoparticles," "ulcerative colitis," and "cyclosporine A." The primary outcomes include histological scores and colon length. The Nano-CSA effects on UC were assessed by analyzing the difference between the treatment and untreated control groups, through the use of standardized mean difference (SMD). A fixed effect model was used where heterogeneity was less than 50%, for higher heterogeneity random effect model was used. The total number of included studies for this systematic review was six, from which meta-analysis was performed on four studies. In all the studies, dextran sulfate sodium (DSS) was used to induce UC, except for one study that used TNBS (2,4,6-trinitrobenzene sulfonic acid) for UC induction. Four studies measured histological score and colon length, and two studies measured other secondary outcomes (IL-6, TNF-α, and MPO (myeloperoxidase activity)). Meta-analysis results have demonstrated that there is an increase in colon length with SMD of 6.879 and a decrease in histological score with SMD of 10.956 in the Nano-CSA treated group. There was also a decrease in the levels of pro-inflammatory cytokines including TNF-α and IL-6 in the Nano-CSA treated group and no significant difference in MPO activity of the two groups. Colon length, MPO activity, and TNF-α expression demonstrated heterogeneity values of 84.638, 86.113, and 51.567 respectively. The results of this meta-analysis have demonstrated the potential therapeutic efficiency of Nano-CSA for the treatment of UC in mice models. Further research is required in order to explore nano-based novel therapeutics options for UC treatment in other models as well as with human applications.

Advances in carbohydrate-based nanoparticles for targeted therapy of inflammatory bowel diseases: A review

The incidence of inflammatory bowel disease (IBD), a chronic gastrointestinal disorder, is rapidly increasing worldwide. Unfortunately, the current therapies for IBD are often hindered by premature drug release and undesirable side effects. With the advancement of nanotechnology, the innovative targeted nanotherapeutics are explored to ensure the accurate delivery of drugs to specific sites in the colon, thereby reducing side effects and improving the efficacy of oral administration. The emphasis of this review is to summarize the potential pathogenesis of IBD and highlight recent breakthroughs in carbohydrate-based nanoparticles for IBD treatment, including their construction, release mechanism, potential targeting ability, and their therapeutic efficacy. Specifically, we summarize the latest knowledge regarding environmental-responsive nano-systems and active targeted nanoparticles. The environmental-responsive drug delivery systems crafted with carbohydrates or other biological macromolecules like chitosan and sodium alginate, exhibit a remarkable capacity to enhance the accumulation of therapeutic drugs in the inflamed regions of the digestive tract. Active targeting strategies improve the specificity and accuracy of oral drug delivery to the colon by modifying carbohydrates such as hyaluronic acid and mannose onto nanocarriers. Finally, we discuss the challenges and provide insight into the future perspectives of colon-targeted delivery systems for IBD treatment.

Chemical modification of α-chymotrypsin enabling its release from alginate hydrogel by electrochemically generated local pH change

This study investigates the controlled release of α-chymotrypsin from an alginate hydrogel matrix. When protein molecules entrapped in the hydrogel matrix have a size smaller than the hydrogel pores, their hold/release from the polymer matrix are controlled by the electrostatic interaction between the guest molecules and host polymer. α-Chymotrypsin, as a model protein, was chemically modified with negatively charged species to change its pI and to convert its attractive interaction with a negatively charged alginate hydrogel matrix to a repulsion interaction allowing its release by pH-triggered signal. Then, bulk pH changes and electrochemically controlled local pH changes resulting from oxygen reduction were used for the controlled release of the enzyme from the alginate hydrogel. Three batches of modified α-chymotrypsin with different linker/enzyme ratios were synthesized, and their release profiles were investigated. The activity of both unmodified and modified α-chymotrypsin was evaluated using a UV-visible spectrophotometer following the standard procedure for the enzymatic assay of α-chymotrypsin (EC 3.4.21.1) and compared across all batches. Direct infusion electrospray ionization mass spectrometry (DI ESI-MS) was used to analyze the protein modifications and their impact on the isoelectric point values.

Time-Separated Pulse Release-Activation of an Enzyme from Alginate-Polyethylenimine Hydrogels Using Electrochemically Generated Local pH Changes

β-Glucosidase (EC 3.2.1.21) from sweet almond was encapsulated into pH-responsive alginate-polyethylenimine (alginate-PEI) hydrogel. Then, electrochemically controlled cyclic local pH changes resulting from ascorbate oxidation (acidification) and oxygen reduction (basification) were used for the pulsatile release of the enzyme from the composite hydrogel. Activation of the enzyme was controlled by the very same pH changes used for β-glucosidase release, separating these two processes in time. Importantly, the activity of the enzyme, which had not been released yet, was inhibited due to the buffering effect of PEI present in the gel. Thus, only a portion of the released enzyme was activated. Both enzymatic activity and release were monitored by confocal fluorescence microscopy and regular fluorescent spectroscopy. Namely, commercially available very little or nonfluorescent substrate 4-methylumbelliferyl-β-d-glucopyranoside was hydrolyzed by β-glucosidase to produce a highly fluorescent product 4-methylumbelliferone during the activation phase. At the same time, labeling of the enzyme with rhodamine B isothiocyanate was used for release observation. The proposed work represents an interesting smart release-activation system with potential applications in biomedical field.

Alginate-Based Encapsulation Fabrication Technique for Drug Delivery: An Updated Review of Particle Type, Formulation Technique, Pharmaceutical Ingredient, and Targeted Delivery System

Alginate is a natural biopolymer widely studied for pharmaceutical applications due to its biocompatibility, low toxicity, and mild gelation abilities. This review summarizes recent advances in alginate-based encapsulation systems for targeted drug delivery. Alginate formulations like microparticles, nanoparticles, microgels, and composites fabricated by methods including ionic gelation, emulsification, spray drying, and freeze drying enable tailored drug loading, enhanced stability, and sustained release kinetics. Alginate microspheres prepared by spray drying or ionic gelation provide gastric protection and colon-targeted release of orally delivered drugs. Alginate nanoparticles exhibit enhanced cellular uptake and tumor-targeting capabilities through the enhanced permeation and retention effect. Crosslinked alginate microgels allow high drug loading and controlled release profiles. Composite alginate gels with cellulose, chitosan, or inorganic nanomaterials display improved mechanical properties, mucoadhesion, and tunable release kinetics. Alginate-based wound dressings containing antimicrobial nanoparticles promote healing of burns and chronic wounds through sustained topical delivery. Although alginate is well-established as a pharmaceutical excipient, more extensive in vivo testing is needed to assess clinical safety and efficacy of emerging formulations prior to human trials. Future opportunities include engineered systems combining stimuli-responsiveness, active targeting, and diagnostic capabilities. In summary, this review discusses recent advances in alginate encapsulation techniques for oral, transdermal, and intravenous delivery, with an emphasis on approaches enabling targeted and sustained drug release for enhanced therapeutic outcomes.

Exploring the potential of pH-sensitive polymers in targeted drug delivery

The pH-sensitive polymers have attained significant attention in the arena of targeted drug delivery (TDD) because of their exceptional capability to respond to alteration in pH in various physiological environments. This attribute aids pH-sensitive polymers to act as smart carriers for therapeutic agents, transporting them precisely to target locations while curtailing the release of drugs in off-targeted sites, thereby diminishing side effects. Many pH-responsive polymers in TDD have revealed promising results, with increased therapeutic efficacy and decreased toxic effects. Several pH-sensitive polymers, including, hydroxy-propyl-methyl cellulose, poly (methacrylic acid) (Eudragit series), poly (acrylic acid), and chitosan, have been broadly studied for their myriad applications in the management of various types of diseases. Additionally, the amalgamation of pH-sensitive polymers with, additive manufacturing techniques like 3D printing, has resulted in the progression of novel drug delivery systems that regulate drug release in a controlled manner. Herein, types of pH-sensitive polymers in TDD are systemically reviewed. We have briefly discussed the nanocarriers employed for the delivery of various pH-sensitive polymers in TDD. Finally, miscellaneous applications of pH-sensitive polymers are discussed thoroughly with special attention to the implication of 3D printing in pH-sensitive polymers.

Designing Advanced Drug Delivery Systems: Core-Shell Alginate Particles through Electro-Fluid Dynamic Atomization

Innovations in drug delivery systems are crucial for enhancing therapeutic efficiency. Our research presents a novel approach based on using electro-fluid dynamic atomization (EFDA) to fabricate core-shell monophasic particles (CSMp) from sodium alginate blends of varying molecular weights. This study explores the morphological characteristics of these particles in relation to material properties and process conditions, highlighting their potential in drug delivery applications. A key aspect of our work is the development of a mathematical model that simulates the release kinetics of small molecules, specifically sodium diclofenac. By assessing the diffusion properties of different molecules and gel formulations through transport and rheological models, we have created a predictive tool for evaluating the efficiency of these particles in drug delivery. Our findings underscore two critical, independent parameters for optimizing drug release: the external shell thickness and the diffusivity ratios within the dual layers. This allows for precise control over the timing and intensity of the release profile. This study advances our understanding of EFDA in the fabrication of CSMp and offers promising avenues for enhancing drug delivery systems by tailoring release profiles through particle characteristic manipulation.

Responsive nanosystems for targeted therapy of ulcerative colitis: Current practices and future perspectives

The pharmacological approach to treating gastrointestinal diseases is suffering from various challenges. Among such gastrointestinal diseases, ulcerative colitis manifests inflammation at the colon site specifically. Patients suffering from ulcerative colitis notably exhibit thin mucus layers that offer increased permeability for the attacking pathogens. In the majority of ulcerative colitis patients, the conventional treatment options fail in controlling the symptoms of the disease leading to distressing effects on the quality of life. Such a scenario is due to the failure of conventional therapies to target the loaded moiety into specific diseased sites in the colon. Targeted carriers are needed to address this issue and enhance the drug effects. Conventional nanocarriers are mostly readily cleared and have nonspecific targeting. To accumulate the desired concentration of the therapeutic candidates at the inflamed area of the colon, smart nanomaterials with responsive nature have been explored recently that include pH responsive, reactive oxygen species responsive (ROS), enzyme responsive and thermo - responsive smart nanocarrier systems. The formulation of such responsive smart nanocarriers from nanotechnology scaffolds has resulted in the selective release of therapeutic drugs, avoiding systemic absorption and limiting the undesired delivery of targeting drugs into healthy tissues. Recent advancements in the field of responsive nanocarrier systems have resulted in the fabrication of multi-responsive systems i.e. dual responsive nanocarriers and derivitization that has increased the biological tissues and smart nanocarrier's interaction. In addition, it has also led to efficient targeting and significant cellular uptake of the therapeutic moieties. Herein, we have highlighted the latest status of the responsive nanocarrier drug delivery system, its applications for on-demand delivery of drug candidates for ulcerative colitis, and the prospects are underpinned.

Recent advances on emerging nanomaterials for diagnosis and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disorder that affects the entire gastrointestinal tract and is associated with an increased risk of colorectal cancer. Mainstream clinical testing methods are time-consuming, painful for patients, and insufficiently sensitive to detect early symptoms. Currently, there is no definitive cure for IBD, and frequent doses of medications with potentially severe side effects may affect patient response. In recent years, nanomaterials have demonstrated considerable potential for IBD management due to their diverse structures, composition, and physical and chemical properties. In this review, we provide an overview of the advances in nanomaterial-based diagnosis and treatment of IBD in recent five years. Multi-functional bio-nano platforms, including contrast agents, near-infrared (NIR) fluorescent probes, and bioactive substance detection agents have been developed for IBD diagnosis. Based on a series of pathogenic characteristics of IBD, the therapeutic strategies of antioxidant, anti-inflammatory, and intestinal microbiome regulation of IBD based on nanomaterials are systematically introduced. Finally, the future challenges and prospects in this field are presented to facilitate the development of diagnosis and treatment of IBD.

Cyclosporine A-Encapsulated pH/ROS Dual-Responsive Nanoformulations for the Targeted Treatment of Colitis in Mice

Inflammatory bowel disease (IBD) is a frequently occurring disease that seriously influences the patient's quality of life. To decrease adverse effects and improve efficacy of therapeutics, nanomedicines have been widely used to treat IBD. However, how to thoroughly release payloads under an inflammatory microenvironment and synergistic therapy of IBD need to be further investigated. To address this issue, cyclosporine A (CsA)-loaded, folic acid (FA)-modified, pH and reactive oxygen species (ROS) dual-responsive nanoparticles (FA-CsA NPs) were fabricated using pH/ROS-responsive material as carrier. The prepared FA-CsA NPs had spherical shape and uniform size distribution and could smartly release their payloads under acid and/or ROS microenvironment. In vitro experiments demonstrated that FA-CsA NPs can be effectively internalized by activated macrophages, and the internalized NPs could down-regulate the expression of proinflammatory cytokines compared to free drug or nontargeted NPs. In vivo experiments verified that FA-CsA NPs significantly accumulated at inflammatory colon tissues and the accumulated NPs obviously improved the symptoms of colitis in mice without obvious adverse effects. In conclusion, our results provided a candidate for the targeted treatment of IBD.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Cyclosporine A-loaded colon-targeted oral nanomicelles self-assembly by galactosylated carboxymethyl chitosan for efficient ulcerative colitis therapy

An oral galactosylated carboxymethyl chitosan polymeric nanomicelles (Gal-N-CMCS NPs) embedded in chitosan-alginate hydrogel (CA-Gel) was developed to load cyclosporine A (CyA) as therapeutic agents against ulcerative colitis (UC). Galactose modified CMCS with macrophage targeting characteristic and CyA via a simple ultrasonication method to form Gal-N-CMCS/CyA NPs, and mixed CA-Gel to acquire the final formulation (Gal-N-CMCS/CyA Gel). The generated Gal-N-CMCS/CyA NPs displayed a desirable particle size (206.8 nm), negative surface charge (-19.5 mV), and high encapsulating efficiency (89.6%). The morphology and release profiles were also charactered by transmission electron microscope [1] and dialysis method, respectively. Strikingly, the mucus penetration of Gal-N-CMCS/CyA NPs exceeded 90% within 90 min. The Gal-N-CMCS NPs internalized by macrophages were 3.3-fold higher than CMCS-N NPs, thereby, enhancing the anti-inflammatory activities of NPs. Meanwhile, these NPs exhibited excellent biocompatibility, reduced the toxic effect of CyA, and targeting ability on inflammatory macrophages both in vitro and in vivo. Most importantly, in vivo studies revealed that CyA NPs could efficiently target the inflamed colon, remarkably alleviate inflammation, repair mucosal and reconstructed colonic epithelial barriers in UC mice induced by dextran sulfate sodium (DSS) via Toll-like receptor 4 -Nuclear factor kappa-B (TLR4-NF-κB) pathway. Our findings suggest that these high-performance and facilely fabricated Gal-N-CMCS/CyA NPs could be developed as a promising drug carrier for oral UC treatment.

Alginate-based drug carrier systems to target inflammatory bowel disease: A review

Inflammatory bowel disease (IBD) is an inflammatory disorder that affects the gastrointestinal tract. IBD has become an increasingly common condition in both developed and developing nations over the last few decades, owing to a variety of factors like a rising population and diets packed with processed and junk foods. While the root pathophysiology of IBD is unknown, treatments are focused on medications aimed to mitigate symptoms. Alginate (AG), a marine-derived polysaccharide, is extensively studied for its biocompatibility, pH sensitivity, and crosslinking nature. This polymer is thoroughly researched in drug delivery systems for IBD treatment, as it is naturally available, non-toxic, cost effective, and can be easily and safely cross-linked with other polymers to form an interconnected network, which helps in controlling the release of drugs over an extended period. There are various types of drug delivery systems developed from AG to deliver therapeutic agents; among them, nanotechnology-based systems and hydrogels are popular due to their ability to facilitate targeted drug delivery, reduce dosage, and increase the therapeutic efficiency. AG-based carrier systems are not only used for the sustained release of drug, but also used in the delivery of siRNA, interleukins, and stem cells for site directed drug delivery and tissue regenerating ability respectively. This review is focussed on pathogenesis and currently studied medications for IBD, AG-based drug delivery systems and their properties for the alleviation of IBD. Moreover, future challenges are also be discoursed to improve the research of AG in the field of biopharmaceuticals and drug delivery.

Mucoadhesive Nanoparticles Enhance the Therapeutic Effect of Dexamethasone on Experimental Ulcerative Colitis by the Local Administration as an Enema

Background

As the first-line drug to treat ulcerative colitis (UC), long-term use of glucocorticoids (GCs) produces severe toxic and side effects. Local administration as enema can increase the local GCs concentrations and reduce systemic exposure to high oral doses by directly delivering GCs to the inflammation site in the distal colorectum. However, UC patients are often accompanied by diarrhea, leading to the short colonic residence time of GCs and failure to exert their function fully.

Purpose

A kind of mucoadhesive nanoparticles (NPs) loading different dexamethasone derivatives (DDs) were developed, which could attach to the positively charged inflammatory colonic mucosa through electrostatic adsorption after administered by enema, thereby improving the local concentration and achieving effective targeted therapy for UC.

Methods

Two DDs, dexamethasone hemisuccinate and dexamethasone phosphate, were synthesized. In NPs preparation, The core PEI-DDs NPs were built by the electrostatic adsorption of DDs and the cationic polymer polyethyleneimine (PEI). Then, the natural polyanionic polysaccharide sodium alginate (SA) was electronically coated around NPs to construct the final SA-PEI-DDs NPs, followed by the in vitro stability and release tests, in vitro and in vivo colonic mucosal adhesion tests. In the in vivo anti-UC test, the experimental colitis mice were induced by 2,4,6-trinitrobenzenesulfonic acid. The body weight and disease activity index changes were measured, and the myeloperoxidase activity, pro-inflammatory cytokines concentration, and hematoxylin and eosin staining were also investigated to evaluate the therapeutic effect of NPs.

Results

The structures of two DDs were demonstrated by ¹H-NMR and MS. Both NPs were negatively charged and achieved high loading efficiency of DDs, while their particle sizes were significantly different. NPs showed good stability and sustained release properties in the simulated colonic environment. Moreover, the negative charge on the of NPs surface made them easier to adhere to the positively charged inflammatory colonic mucosa, thereby enhancing the enrichment and retention of DDS in the colitis site. Furthermore, the NPs exhibited better therapeutic effects than free Dex on the experimental colitis mice induced by TNBS through the enema rectal.

Conclusion

These results indicated the mucoadhesive NPs as a kind of novel nano-enema showed great potential to achieve efficient treatment on UC.

ROS-triggered self-disintegrating and pH-responsive astaxanthin nanoparticles for regulating the intestinal barrier and colitis

Smart delivery systems with stimuli-responsive capability are able to improve the bioaccessibility through increasing the solubility, physicochemical stability and biocompatibility of bioactive compounds. In this study, the astaxanthin nanoparticles with reactive oxygen species (ROS) and pH dual-response function were design and constructed using poly (propylene sulfide) covalently modified sodium alginate as carriers based on ultrasonic assisted self-assembly strategy. Atomic force microscope and scanning electron microscope analysis showed that the nanoparticles were spherical in shape with a size of around 260 nm. Meanwhile, the astaxanthin nanoparticles showed both pH and ROS stimuli-responsive release characteristics. In vitro cell experiments showed that astaxanthin nanoparticles significantly inhibited the production of ROS and mitochondrial depolarization induced by oxidative stress. In vivo colitis experiment of mice revealed that astaxanthin nanoparticles could significantly relieve colitis, protect the integrity of colon tissue and restore the expression of tight junction proteins ZO-1 and occludin. The abundance of Lactobacillus and Lachnospiraceae, and the ratio of Firmicutes/Bacteroidota of gut microbiota were significantly improved after intervention of the stimuli-responsive astaxanthin nanoparticles. This work provided a simple strategy for constructing ROS/pH dual response delivery system, which provided an experimental basis for improving the oral bioavailability of hydrophobic active compounds.

Cupriavidus necator-Produced Polyhydroxybutyrate/Eudragit FS Hybrid Nanoparticles Mitigates Ulcerative Colitis via Colon-Targeted Delivery of Cyclosporine A

Polyhydroxybutyrate (PHB) has emerged as a novel material for replacing various plastics used in the medical field. However, its application as a drug-delivery carrier for colitis-targeted delivery has not been explored. In this study, we used biosynthesized PHB combined with Eudragit FS (EFS) and cyclosporine A (CSA) to develop pH-responsive controlled CSA-releasing nanoparticles (CSA-PENPs) for colitis-targeted drug delivery and demonstrated its enhanced therapeutic efficacy in a dextran sulfate sodium (DSS)-induced murine colitis model. PHB was successfully biosynthesized in the bacterium Cupriavidus necator, as demonstrated by ¹H-NMR and FT-IR analyses. CSA-PENPs were fabricated via the oil-in-water emulsion solvent evaporation method. Owing to the potent pH-responsive and sustained drug release properties provided by PHB and EFS, CSA-PENPs could deliver a sufficient amount of CSA to inflamed tissues in the distal colon; in contrast, CSA-loaded EFS nanoparticles displayed premature burst release before reaching the target site. Due to enhanced CSA delivery to colitis tissues, CSA-PENPs exhibited potent anti-inflammatory effects in the DSS-induced murine colitis model. Overall, CSA-PENPs could be a promising drug-delivery system for treating ulcerative colitis.

5-Fluorouracil crystal-incorporated, pH-responsive, and release-modulating PLGA/Eudragit FS hybrid microparticles for local colorectal cancer-targeted chemotherapy

5-Fluorouracil (5-FU) is a widely used chemotherapeutic agent for colorectal cancer (CRC) owing to its potent anticancer effects. However, severe systemic side effects and poor drug accumulation in the CRC tissues limit its efficacy. This study aimed to develop 5-FU crystal-incorporated, pH-responsive, and release-modulating poly(d,l-lactide-co-glycolide)/Eudragit FS hybrid microparticles (5FU-EPMPs) for the local CRC-targeted chemotherapy. Approximately 150 μm 5FU-EPMPs were fabricated via the S/O/W emulsion solvent evaporation method, with 7.93 ± 0.24% and 87.23 ± 2.64% 5-FU loading and encapsulation efficiencies, respectively. Drug release profiles in a simulated pH environment of the gastrointestinal tract revealed that premature 5-FU release in the stomach and small intestine was prevented, thereby minimizing systemic 5-FU absorption. After reaching the colon, 5-FU was continuously released for >15 h, allowing long-term exposure of CRC tissues to sufficient 5-FU concentrations. Furthermore, in a CRC mouse model, the 5FU-EPMPs showed potent inhibition of tumor growth without signs of systemic toxicity. Thus, the 5FU-EPMPs represent a promising drug delivery system for local CRC-targeted chemotherapy.

On-demand reconstitutable hyaluronic acid-doped azathioprine microcrystals effectively ameliorate ulcerative colitis via selective accumulation in inflamed tissues

Although CD44-targeted delivery of pure drug microcrystals of azathioprine (AZA) could be a desirable approach to treat ulcerative colitis (UC), premature drug release and systemic absorption before reaching the colitis region remain a major obstacle. In this study, to overcome these limitations, we developed on-demand reconstitutable HA-doped AZA microcrystals (EFS/HA-AZAs) via incorporating hyaluronic acid (HA)-doped AZA microcrystals (HA-AZAs) into a Eudragit FS (EFS) microcomposite. Since EFS acts as a protective layer, the premature release of AZA in the simulated conditions of the stomach and small intestine was substantially reduced, while HA-AZAs were successfully reconstituted from the EFS/HA-AZAs in the colonic environment, resulting from the pH-triggered dissolution of EFS. After complete reconstitution of HA-AZAs in the colon, HA-AZAs selectively accumulated in the inflamed region via the HA-CD44 interaction. Owing to successful colitis-targeted delivery, EFS/HA-AZAs showed potent anti-inflammatory effects in a dextran sulfate sodium-induced murine colitis model within 7 days without systemic toxicity. These results suggest that EFS/HA-AZAs could be a promising drug delivery system for UC treatment.

Bupi Yichang Pill alleviates dextran sulfate sodium-induced ulcerative colitis in mice by regulating the homeostasis of follicular helper T cells

BACKGROUND

Follicular helper T (Tfh) cells-based therapy represents a new treatment option for inflammatory bowel disease. Bupi Yichang Pill (BPYCP), a traditional Chinese formula for the treatment of dysentery and diarrhea, exhibits potential anti-inflammatory activities in treating various kinds of inflammation. However, its anti-inflammatory effect on colitis and the underlying mechanisms remain unknown.

PURPOSE

To explore the protective role and underlying immunomodulatory effects of BPYCP in the treatment of UC.

METHODS

The dextran sodium sulfate (DSS) free-drinking method induced UC in C57BL/6 mice, and BPYCP was orally administrated at a dosage of 1.5, 3.0, or 6.0 g/kg/day. Throughout the experimental period, the effects of BPYCP on DSS-induced clinical symptoms and disease activity index (DAI) were monitored and analyzed. Hematoxylin-eosin staining was used to observe the histopathological injury of the colon. Flow cytometry was used to detect the levels of Tfh cells, Tfh cell subpopulations, and memory Tfh cells. ELISA, Western blot, and qRT-PCR were used to detect the expression of inflammatory cytokines and Tfh cell-related biomarkers.

RESULTS

Medium and high dosages of BPYCP effectively alleviated DSS-induced experimental colitis with increased body weight, survival rate and colonic length, and decreased DAI, colonic weight, and colonic index, as well as less ulcer formation and inflammatory cell infiltration, increased anti-inflammatory cytokine IL-10, and decreased pro-inflammatory cytokines IL-17A, IL-6, and TNF-ɑ. Moreover, BPYCP administration significantly decreased the percentage of Tfh cells and the expression of Tfh markers ICOS, PD-1 and Bcl-6 in the mesenteric lymph nodes of colitis mice. In addition, BPYCP treatment obviously decreased the percentages of Tfh1, Tfh17 and Tem-Tfh cells and upregulated Tfr cells in colitis mice. However, there were no significant regulatory effects of BPYCP on Tfh cell response in normal mice.

CONCLUSION

Taken together, these results demonstrated a protective effect of BPYCP against DSS-induced experimental colitis by regulating Tfh cell homeostasis.

3D printed tablets containing oxaliplatin loaded alginate nanoparticles for colon cancer targeted delivery. An in vitro/in vivo study

This study aimed to develop a colon-targeted tablet of oxaliplatin (OP) using the combination of nanotechnology and fused deposition modeling (FDM) 3D printing to improve its antitumor activity, tumor targetability, and safety profile. Eudragit L100-55 filament containing OP loaded alginate nanoparticles (OP-NPs) were fabricated using hot-melt extrusion method and printed by an FDM printer to 3D printed tablets with good uniformity in the drug content and selective release of OP in the colonic environment. The antitumor effect of 3D printed tablets containing OP-NPs in CT-26 tumor-bearing mice was evaluated compared to intravenous and oral administration of OP solution, and compressed tablets containing OP-NPs, which were prepared by direct compression method with the same formulation. The antitumor effect of 3D printed tablets containing OP-NPs was remarkable and comparable with intravenous OP solution (p ˃ 0.05) with a better safety profile, whereas compressed tablets did not show any significant antitumor effect, probably in terms of non-selective drug release in stomach and upper intestine environments. This study highlights the potential of the combination of nanotechnology and 3D printing in the preparation of colon-specific drug delivery systems of chemotherapeutic drugs with good antitumor activity, tumor targetability, and safety profile for colorectal cancer treatment.