Local treatment of experimental colitis in the rat by negatively charged liposomes of catalase, TMN and SOD

Clickable nanozyme enhances precise colonization of probiotics for ameliorating inflammatory bowel disease

Convincing evidence suggests that aberrant gut microbiota changes play a critical role in the progression and pathogenesis of inflammatory bowel disease (IBD). Probiotic therapeutic interventions targeting the microbiota may provide alternative avenues to treat IBD, but currently available probiotics often suffer from low intestinal colonization and limited targeting capability. Here, we developed azido (N3)-modified Prussian blue nanozyme (PB@N3) spatio-temporal guidance enhances the targeted colonization of probiotics to alleviate intestinal inflammation. First, clickable PB@N3 targets intestinal inflammation, simultaneously, it scavenges reactive oxygen species (ROS). Subsequently, utilizing "click" chemistry to spatio-temporally guide targeted colonization of dibenzocyclooctyne (DBCO)-modified Lactobacillus reuteri DSM 17938 (LR@DBCO). The "click" reaction between PB@N3 and LR@DBCO has excellent specificity and efficacy both in vivo and in vitro. Despite the complex physiological environment of IBD, "click" reaction can prolong the retention time of probiotics in the intestine. Dextran sulfate sodium (DSS)-induced colitis mice model, demonstrates that the combination of PB@N3 and LR@DBCO effectively mitigates levels of ROS, enhances the colonization of probiotics, modulates intestinal flora composition and function, regulates immune profiles, restores intestinal barrier function, and alleviates intestinal inflammation. Hence, PB@N3 spatio-temporal guidance enhances targeted colonization of LR@DBCO provides a promising medical treatment strategy for IBD.

Microbially Inspired Calcium Carbonate Precipitation Pathway Integrated Polyelectrolyte Capsules (MICPC) for Biomolecules Release

Complexation between oppositely charged polyelectrolytes offers a facile single-step strategy for assembling functional micro-nano carriers for efficient drug and vaccine delivery. However, the stability of the delivery system within the physiological environment is compromised due to the swelling of the polyelectrolyte complex, driven by the charge shielding effect, and consequently leads to uncontrollable burst release, thereby limiting its potential applications. In a pioneering approach, cellular pathway-inspired calcium carbonate precipitation pathways are developed that are integrated into polyelectrolyte capsules (MICPC). These innovative capsules are fabricated at the interface of all-aqueous microfluidic droplets, resulting in a precisely controllable and sustained release profile in physiological conditions. Unlike single-step polyelectrolyte assembly capsules which always perform rapid burst release, the MICPC exhibits a sustainable and tunable release pattern, releasing biomolecules at an average rate of 3-10% per day. Remarkably, the degree of control over MICPC's release kinetics can be finely tuned by adjusting the quantity of synthesized calcium carbonate particles within the polyelectrolyte complex. This groundbreaking work not only deepens the insights into polyelectrolyte complexation but also significantly enhances the overall stability of these complexes, opening up new avenues for expanding the range of applications involving polyelectrolyte complex-related materials.

Oral liposomal delivery of an activatable budesonide prodrug reduces colitis in experimental mice

Inflammatory bowel disease (IBD) is one of the most common intestinal disorders, with increasing global incidence and prevalence. Numerous therapeutic drugs are available but require intravenous administration and are associated with high toxicity and insufficient patient compliance. Here, an oral liposome that entraps the activatable corticosteroid anti-inflammatory budesonide was developed for efficacious and safe IBD therapy. The prodrug was produced via the ligation of budesonide with linoleic acid linked by a hydrolytic ester bond, which was further constrained into lipid constituents to form colloidal stable nanoliposomes (termed budsomes). Chemical modification with linoleic acid augmented the compatibility and miscibility of the resulting prodrug in lipid bilayers to provide protection from the harsh environment of the gastrointestinal tract, while liposomal nanoformulation enables preferential accumulation to inflamed vasculature. Hence, when delivered orally, budsomes exhibited high stability with low drug release in the stomach in the presence of ultra-acidic pH but released active budesonide after accumulation in inflamed intestinal tissues. Notably, oral administration of budsomes demonstrated favorable anti-colitis effect with only ∼7% mouse body weight loss, whereas at least ∼16% weight loss was observed in other treatment groups. Overall, budsomes exhibited higher therapeutic efficiency than free budesonide treatment and potently induced remission of acute colitis without any adverse side effects. These data suggest a new and reliable approach for improving the efficacy of budesonide. Our in vivo preclinical data demonstrate the safety and increased efficacy of the budsome platform for IBD treatment, further supporting clinical evaluation of this orally efficacious budesonide therapeutic.

Systemic administration of budesonide in pegylated liposomes for improved efficacy in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory condition affecting the nasal and paranasal sinuses of approximately 11.5% of the United States adult population. Oral corticosteroids are effective in controlling sinonasal inflammation in CRS, but the associated adverse effects limit their clinical use. Topical budesonide has demonstrated clinical efficacy in patients with CRS. Herein, we investigated the systemic delivery of liposomes tethered with poly(ethylene glycol) (PEG) and loaded with budesonide in a murine model of CRS. PEGylated liposomes encapsulated with budesonide phosphate (L-BudP) were administered via tail vein injection, and the feasibility of L-BudP to reduce sinonasal inflammation was compared to that of free budesonide phosphate (F-BudP) and topical budesonide phosphate (T-BudP) treatment over a 14-day study period. Compared to a single injection of F-BudP and repeat T-BudP administration, a single injection of L-BudP demonstrated increased and prolonged efficacy, resulting in the significant improvement of sinonasal tissue histopathological scores (p < 0.05) with decreased immune cell infiltration (p < 0.05). Toxicities associated with L-BudP and T-BudP treatment, assessed via body and organ weight, as well as peripheral blood liver enzyme and differential white blood cell analyses, were transient and comparable. These data suggest that systemic liposomal budesonide treatment results in improved efficacy over topical treatment.

Study of Salidroside and Its Inflammation Targeting Emulsion Gel for Wound Repair

Salidroside has been widely used in anti-tumor, cardiovascular, and cerebrovascular protection. However, there are few reports of its use for wound repair. Herein, salidroside inflammation-targeted emulsion gel and non-targeted emulsion gel were developed for wound repair. The inflammation-targeted emulsion gels showed an overall trend of better transdermal penetration and lower potential than non-targeted emulsion gels (-58.7 mV and -1.6 mV, respectively). The apparent improvement of the trauma surface was significant in each administration group. There was a significant difference in the rate of wound healing of the rats between each administration group and the model group at days 7 and 14. Pathological tissue sections showed that inflammatory cells in the epidermis, dermis, and basal layer were significantly reduced, and the granulation tissue was proliferated in the inflammation-targeted emulsion gel group and the non-targeted emulsion gel group. Regarding the expressions of EGF and bFGF, the expressions of bFGF and EGF in the tissues of the inflammation-targeted group at days 7, 14, or 21 were significantly higher than that of the non-targeted emulsion gel group and the model group, both of which were statistically significant compared with the model group (p < 0.05). These results demonstrated that salidroside has the potential as an alternative drug for wound repair.

Multifunctional hydrogels based on chitosan, hyaluronic acid and other biological macromolecules for the treatment of inflammatory bowel disease: A review

Hydrogel is a three-dimensional network polymer material rich in water. It is widely used in the biomedical field because of its unique physical and chemical properties and good biocompatibility. In recent years, the incidence of inflammatory bowel disease (IBD) has gradually increased, and the disadvantages caused by traditional drug treatment of IBD have emerged. Therefore, there is an urgent need for new treatments to alleviate IBD. Hydrogel has become a potential therapeutic platform. However, there is a lack of comprehensive review of functional hydrogels for IBD treatment. This paper first summarizes the pathological changes in IBD sites. Then, the action mechanisms of hydrogels prepared from chitosan, sodium alginate, hyaluronic acid, functionalized polyethylene glycol, cellulose, pectin, and γ-polyglutamic acid on IBD were described from aspects of drug delivery, peptide and protein delivery, biologic therapies, loading probiotics, etc. In addition, the advanced functions of IBD treatment hydrogels were summarized, with emphasis on adhesion, synergistic therapy, pH sensitivity, particle size, and temperature sensitivity. Finally, the future development direction of IBD treatment hydrogels has been prospected.

Gold nanoparticles-embedded ceria with enhanced antioxidant activities for treating inflammatory bowel disease

The excessive reactive oxygen species (ROS) is a hallmark associated with the initiation and progression of inflammatory bowel disease (IBD), which execrably form a vicious cycle of ROS and inflammation to continually promote disease progression. Here, the gold nanoparticles-embedded ceria nanoparticles (Au/CeO₂) with enhanced antioxidant activities are designed to block this cycle reaction for treating IBD by scavenging overproduced ROS. The Au/CeO₂ with core-shell and porous structure exhibits significantly higher enzymatic catalytic activities compared with commercial ceria nanoparticles, likely due to the effective exposure of catalytic sites, higher content of Ce (III) and oxygen vacancy, and accelerated reduction from Ce (IV) to Ce (III). Being coated with negatively-charged hyaluronic acid, the Au/CeO₂@HA facilitates accumulation in inflamed colon tissues via oral administration, reduces pro-inflammatory cytokines, and effectively alleviates colon injury in colitis mice. Overall, the Au/CeO₂@HA with good biocompatibility is a promising nano-therapeutic for treating IBD.

Self-assembled micelle derived from pterostilbene ameliorate acute inflammatory bowel disease

PEGylated pterostilbene micelle (PTENPs) with higher bioavailability, biocompatibility, and water solubility were prepared. Then we detected the therapeutic effects in the treatment of inflammatory bowel disease (IBD), together with its potential mechanisms. The anti-oxidant effects and anti-inflammatory effects of PTENPs were determined under in vitro and in vivo conditions. Besides, the cellular toxicity of the PTENPs was determined in vitro, and biocompatibility testing was performed on a colitis mice model to determine its safety. The self-assembled PTENPs showed potency in treating IBD, which was featured by effectively anti-oxidant capacity, inhibition of cellular damages, and an anti-inflammatory role. In addition, PTENPs could inhibit the activation of TLR4, thereby inhibiting the NF-κB and MAPK signaling pathways. Meanwhile, it could protect colonic tissues from oxidative damage, which promoted the remission of colonic inflammation with low toxicity. Compared with free PTE, PTENPs could effectively ameliorate acute IBD with low toxicity, which may be related to the inactivation of TLR4, and inhibition of NF-κB and MAPK signaling pathways.

Targeting pathophysiological changes using biomaterials-based drug delivery systems: A key to managing inflammatory bowel disease

Inflammatory bowel disease (IBD) is a gastrointestinal disorder, affecting about several million people worldwide. Current treatments fail to adequately control some clinical symptoms in IBD patients, which can adversely impact the patient's quality of life. Hence, the development of new treatments for IBD is needed. Due to their unique properties such as biocompatibility and sustained release of a drug, biomaterials-based drug delivery systems can be regarded as promising candidates for IBD treatment. It is noteworthy that considering the pathophysiological changes occurred in the gastrointestinal tract of IBD patients, especially changes in pH, surface charge, the concentration of reactive oxygen species, and the expression of some biomolecules at the inflamed colon, can help in the rational design of biomaterials-based drug delivery systems for efficient management of IBD. Here, we discuss about targeting these pathophysiological changes using biomaterials-based drug delivery systems, which can provide important clues to establish a strategic roadmap for future studies.

Novel drug delivery systems for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic illness characterized by relapsing inflammation of the intestines. The disorder is stratified according to the severity and is marked by its two main phenotypical representations: Ulcerative colitis and Crohn’s disease. Pathogenesis of the disease is ambiguous and is expected to have interactivity between genetic disposition, environmental factors such as bacterial agents, and dysregulated immune response. Treatment for IBD aims to reduce symptom extent and severity and halt disease progression. The mainstay drugs have been 5-aminosalicylates (5-ASAs), corticosteroids, and immunosuppressive agents. Parenteral, oral and rectal routes are the conventional methods of drug delivery, and among all, oral administration is most widely adopted. However, problems of systematic drug reactions and low specificity in delivering drugs to the inflamed sites have emerged with these regular routes of delivery. Novel drug delivery systems have been introduced to overcome several therapeutic obstacles and for localized drug delivery to target tissues. Enteric-coated microneedle pills, various nano-drug delivery techniques, prodrug systems, lipid-based vesicular systems, hybrid drug delivery systems, and biologic drug delivery systems constitute some of these novel methods. Microneedles are painless, they dislodge their content at the affected site, and their release can be prolonged. Recombinant bacteria such as genetically engineered Lactococcus Lactis and eukaryotic cells, including GM immune cells and red blood cells as nanoparticle carriers, can be plausible delivery methods when evaluating biologic systems. Nano-particle drug delivery systems consisting of various techniques are also employed as nanoparticles can penetrate through inflamed regions and adhere to the thick mucus of the diseased site. Prodrug systems such as 5-ASAs formulations or their derivatives are effective in reducing colonic damage. Liposomes can be modified with both hydrophilic and lipophilic particles and act as lipid-based vesicular systems, while hybrid drug delivery systems containing an internal nanoparticle section for loading drugs are potential routes too. Leukosomes are also considered as possible carrier systems, and results from mouse models have revealed that they control anti- and pro-inflammatory molecules.

A KPV-binding double-network hydrogel restores gut mucosal barrier in an inflamed colon

Ulcerative colitis (UC) usually occurs in the superficial mucosa of the colorectum. Here, a double-network hydrogel (PMSP) was constructed from maleimided γ-polyglutamic acid and thiolated γ-polyglutamic acid through crosslinking of thiol-maleimide and self-oxidized thiols. PMSP with a negative charge specifically adhered to the inflamed mucosa with positively charged proteins rather than to the healthy mucosa. PMSP exhibited good mechanical strength with storage modulus (G') of 17.6 Pa and a linear viscoelastic region (LVR) of 107.2% strain. Moreover, PMSP showed a stronger bio-adhesive force toward the inflamed tissue-mimicking substrate than toward its healthy counterpart. In vivo imaging confirmed that PMSP specifically adhered to the inflamed colonic mucosa of rats with TNBS-induced UC. KPV (Lys-Pro-Val) as a model drug was easily captured by PMSP through electrostatic interactions, thus retaining its bioactivity for a longer time under high temperature conditions. Moreover, the alleviating effect of KPV on rats with TNBS-induced colitis was significantly improved by PMSP after intracolonic administration. The epithelial barrier of the colon also effectively recovered following PMSP-KPV treatment. PMSP-KPV also modulated the gut flora, markedly augmenting the abundance of beneficial microorganisms in gut homeostasis. The mechanism by which PMSP-KPV induces a therapeutic effect may be associated with the inhibition of oxidative stress. Conclusively, the PMSP hydrogel seems to be a promising rectal delivery system for the therapy of UC. STATEMENT OF SIGNIFICANCE: Ulcerative colitis (UC) is a chronic and relapsing disease of the gastrointestinal tract. A key therapeutic approach to treat UC is to repair the mucosal barriers. Here, a double-network hydrogel (PMSP) was constructed from maleimided and thiolated γ-polyglutamic acid through crosslinking of thiol-maleimide and self-oxidized thiols. The negatively charged PMSP specifically adhered to the inflamed colon rather than its healthy counterpart and was retained for a longer time. KPV as a model drug was easily captured by PMSP, which provided better stability to KPV when exposed to high temperature of 50 °C. The epithelial mucosal barrier of the colon was effectively recovered by the rectal administration of PMSP-KPV to rats with TNBS-induced UC. Moreover, PMSP-KPV modulated the gut flora of colitic rats, markedly augmenting the abundance of beneficial microorganisms. Conclusively, PMSP seems to be a promising rectal delivery system for UC therapy.

Liposomes as Tools to Improve Therapeutic Enzyme Performance

The drugs concept has changed during the last few decades, meaning the acceptance of not only low molecular weight entities but also macromolecules as bioagent constituents of pharmaceutics. This has opened a new era for a different class of molecules, namely proteins in general and enzymes in particular. The use of enzymes as therapeutics has posed new challenges in terms of delivery and the need for appropriate carrier systems. In this review, we will focus on enzymes with therapeutic properties and their applications, listing some that reached the pharmaceutical market. Problems associated with their clinical use and nanotechnological strategies to solve some of their drawbacks (i.e., immunogenic reactions and low circulation time) will be addressed. Drug delivery systems will be discussed, with special attention being paid to liposomes, the most well-studied and suitable nanosystem for enzyme delivery in vivo. Examples of liposomal enzymatic formulations under development will be described and successful pre-clinical results of two enzymes, L-Asparaginase and Superoxide dismutase, following their association with liposomes will be extensively discussed.

SHARP hydrogel for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a relapsing and remitting inflammatory disease affecting millions of people worldwide. The active phase of IBD is characterized by excessive formation of reactive oxygen species (ROS) in the intestinal mucosa, which further accelerates the inflammatory process. A feasible strategy for the IBD treatment is thus breaking the oxidation-inflammation vicious circle by scavenging excessive ROS with the use of a suitable antioxidant. Herein, we have developed a novel hydrogel system for oral administration utilizing sterically hindered amine-based redox polymer (SHARP) incorporating covalently bound antioxidant SHA groups. SHARP was prepared via free-radical polymerization by covalent crosslinking of 2-hydroxyethyl methacrylate (HEMA), poly(ethylene oxide) methyl ether methacrylate (PEGMA) and a SHA-based monomer, N-(2,2,6,6-tetramethyl-piperidin-4-yl)-methacrylamide. The SHARP hydrogel was resistant to hydrolysis and swelled considerably (∼90% water content) under the simulated gastrointestinal tract (GIT) conditions, and exhibited concentration-dependent antioxidant properties in vitro against different ROS. Further, the SHARP hydrogel was found to be non-genotoxic, non-cytotoxic, non-irritating, and non-absorbable from the gastrointestinal tract. Most importantly, SHARP hydrogel exhibited a statistically significant, dose-dependent therapeutic effect in the mice model of dextran sodium sulfate (DSS)-induced acute colitis. Altogether, the obtained results suggest that the SHARP hydrogel strategy holds a great promise with respect to IBD treatment.

Broad-Spectrum Reactive Oxygen Species Scavenging and Activated Macrophage-Targeting Microparticles Ameliorate Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a refractory chronic inflammatory disease. An excessively high level of reactive oxygen species (ROS) in the colon is one of the characteristics and pathogenic factors of IBD. Therefore, scavenging excessive ROS is a feasible method to treat IBD. Because ROS include many types of species, scavenging a single kind of ROS is not enough to reduce the ROS level and cure IBD effectively. Herein, broad-spectrum ROS scavenging and activated macrophage-targeting microparticles (MPs) are successfully fabricated by coprecipitation of catalase (CAT) and bovine serum albumin into a MnCO₃ template followed by deposition of polydopamine (PDA), assembly of targeting molecules on the surface, and finally removal of MnCO₃. The CAT content of MPs is about 34.1%. The obtained MPs can effectively scavenge the broad spectrum of ROS and retain 88% of the radical scavenging activity even after the treatment of simulated gastric fluid. The surface-modified dextran sulfate endows MPs with the targeting ability toward activated macrophages, achieving a better therapeutic effect. The MPs with components mostly derived from natural substances exhibit good biocompatibility and can show excellent ROS scavenging ability in cell experiments. In animal experiments, oral administration of a proper dosage of MPs can substantially mitigate colonic inflammation, as evidenced by disease activity index scores reduced by ∼40%, reduced body weight loss, and the production of typical proinflammatory cytokines in the inflammatory colon. This kind of MP can also be utilized for the treatment of other inflammatory diseases.

Liposomal N-acylethanolamine-hydrolyzing acid amidase (NAAA) inhibitor F96 as a new therapy for colitis

Despite numerous advances in the pathological mechanism of inflammatory bowel disease (IBDs), the ideal therapy is still missing. N-Acylethanolamine-hydrolyzing acid amidase (NAAA), a cysteine hydrolase that deactivates fatty acid ethanolamides, has been recognized as a new therapeutic target for IBDs. Herein, we proposed liposomal F96, a selective and potent NAAA inhibitor, as a new therapy for IBDs. F96, with an IC₅₀ of 270 nM for NAAA, was encapsulated into anionic liposome and the anti-inflammatory activity was evaluated in dextran sulfate sodium (DSS) induced colitis mice. The anionic liposomes showed significantly higher accumulation in the colon compared with the small intestine and cecum at 6 and 10 h after administration in DSS induced colitis mice. DSS induction significantly increased myeloperoxidase (MPO) activities and shortened the colon length, while free F96 significantly lowered tissue MPO activity and restored the colon length. Anionic liposome encapsulation significantly enhanced the therapeutic efficacy of F96, as liposomal F96 resulted in lower MPO activity and better colon length restoration effects compared with those treated with free F96. This study offers a new treatment option for colitis, which may pave the way for new therapies for other IBDs.

Liposomal NAAA inhibitor F96 exhibits potent therapeutic activities against colitis.

Bioresponsive drug delivery systems in intestinal inflammation: State-of-the-art and future perspectives

Oral colon-specific delivery systems emerged as the main therapeutic cargos by making a significant impact in the field of modern medicine for local drug delivery in intestinal inflammation. The site-specific delivery of therapeutics (aminosalicylates, glucocorticoids, biologics) to the ulcerative mucus tissue can provide prominent advantages in mucosal healing (MH). Attaining gut mucosal healing and anti-fibrosis are main treatment outcomes in inflammatory bowel disease (IBD). The pharmaceutical strategies that are commonly used to achieve a colon-specific drug delivery system include time, pH-dependent polymer coating, prodrug, colonic microbiota-activated delivery systems and a combination of these approaches. Amongst the different approaches reported, the use of biodegradable polysaccharide coated systems holds great promise in delivering drugs to the ulcerative regions. The present review focuses on major physiological gastro-intestinal tract challenges involved in altering the pharmacokinetics of delivery systems, pathophysiology of MH and fibrosis, reported drug-polysaccharide cargos and focusing on conventional to advanced disease responsive delivery strategies, highlighting their limitations and future perspectives in intestinal inflammation therapy.

Nanozyme-mediated catalytic nanotherapy for inflammatory bowel disease

The overproduction of reactive oxygen species (ROS) is linked to inflammatory bowel disease (IBD) and causes oxidative damage to DNA, proteins, and lipids. These ROS promote the initiation and progression of ulcerative colitis (UC). This study proposes a unique concept of nanomaterials with intrinsic enzyme-like activity (nanozymes) to mediate catalytic nanotherapy for IBD. Methods: We first synthesized manganese Prussian blue nanozymes (MPBZs) with multi-enzyme activity. A dextran sulfate sodium (DSS)-induced mouse model of colitis was built. The ROS scavenging capacity and anti-inflammatory effects of the MPBZs were investigated. Results: As a proof of concept, MPBZs with multi-enzyme activity were constructed of variable valence elements (Mn and Fe) via a facile and efficient strategy. Due to the increased intestinal permeability and positively charged surfaces of inflamed mucosa in murine colitis, the prepared MPBZs with nanoscale sizes and negative charges preferentially accumulated at inflamed sites after oral administration. Importantly, MPBZs mediated catalytic nanotherapy for IBD in mice via a primary effect on the toll-like receptor signaling pathway without adverse side effects. Conclusion: MPBZs with multi-enzyme activity were constructed to treat IBD. This nanozyme-based approach is a promising strategy for catalytic nanotherapy in patients with colonic IBD.

Local delivery of macromolecules to treat diseases associated with the colon

Current treatments for intestinal diseases including inflammatory bowel diseases, irritable bowel syndrome, and colonic bacterial infections are typically small molecule oral dosage forms designed for systemic delivery. The intestinal permeability hurdle to achieve systemic delivery from oral formulations of macromolecules is challenging, but this drawback can be advantageous if an intestinal region is associated with the disease. There are some promising formulation approaches to release peptides, proteins, antibodies, antisense oligonucleotides, RNA, and probiotics in the colon to enable local delivery and efficacy. We briefly review colonic physiology in relation to the main colon-associated diseases (inflammatory bowel disease, irritable bowel syndrome, infection, and colorectal cancer), along with the impact of colon physiology on dosage form design of macromolecules. We then assess formulation strategies designed to achieve colonic delivery of small molecules and concluded that they can also be applied some extent to macromolecules. We describe examples of formulation strategies in preclinical research aimed at colonic delivery of macromolecules to achieve high local concentration in the lumen, epithelial-, or sub-epithelial tissue, depending on the target, but with the benefit of reduced systemic exposure and toxicity. Finally, the industrial challenges in developing macromolecule formulations for colon-associated diseases are presented, along with a framework for selecting appropriate delivery technologies.

Advances in Pharmaceutical Strategies Enhancing the Efficiencies of Oral Colon-Targeted Delivery Systems in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a common disease characterized by chronic inflammation in gastrointestinal tracts, which is primarily treated by administering anti-inflammatory and immunosuppressive drugs that inhibit the burden of intestinal inflammation and improve disease-related symptoms. However, the established therapeutic strategy has limited therapeutic efficacy and adverse drug reactions. Therefore, new disease-targeting drug-delivery strategies to develop more effective treatments are urgent. This review provides an overview of the drug-targeting strategies that can be used to treat IBD, and our recent attempts on the colon-specific delivery system (Pae-SME-CSC) with a paeonol-loaded self-microemulsion (Pae-SMEDDS) are introduced.

Nanoparticulate Drug Delivery Systems Targeting Inflammation for Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic, idiopathic inflammatory set of conditions that can affect the entire gastrointestinal (GI) tract and is associated with an increased risk of colorectal cancer. To date there is no curative therapy for IBD; therefore life-long medication can be necessary for IBD management if surgery is to be avoided. Drug delivery systems specific to the colon have improved IBD treatment and several such systems are available to patients. However, current delivery systems for IBD do not target drugs to the site of inflammation, which leads to frequent dosing and potentially severe side effects that can adversely impact patients' adherence to medication. There is a need for novel drug delivery systems that can target drugs to the site of inflammation, prolong local drug availability, improve therapeutic efficacy, and reduce drug side effects. Nanoparticulate (NP) systems are attractive in designing targeted drug delivery systems for the treatment of IBD because of their unique physicochemical properties and capability of targeting the site of disease. This review analyzes the microenvironment at the site of inflammation in IBD, highlighting the pathophysiological features as possible cues for targeted delivery; discusses different strategies and mechanisms of NP targeting IBD, including size-, charge-, ligand-receptor, degradation- and microbiome-mediated approaches; and summarizes recent progress on using NPs towards improved therapies for IBD. Finally, challenges and future directions in this field are presented to advance the development of targeted drug delivery for IBD treatment.

Role of enzymatic free radical scavengers in management of oxidative stress in autoimmune disorders

Autoimmune disorders are distinct with over production and accumulation of free radicals due to its undisclosed genesis. The cause of numerous disorders as cancer, arthritis, psoriasis, diabetes, alzheimer's, cardiovascular disease, Parkinson's, respiratory distress syndrome, colitis, crohn's, pulmonary fibrosis, obesity and ageing have been associated with immune dysfunction and oxidative stress. In an oxidative stress, reactive oxygen species generally provoke the series of oxidation at cellular level. The buildup of free radicals in turn triggers various inflammatory cells causing release of various inflammatory interleukins, cytokines, chemokines, and tumor necrosis factors which mediate signal transduction and transcription pathways as nuclear factor- kappa B (NF-κB), signal transducer and activator of transcription 3 (STAT3), hypoxia-inducible factor-1 (HIF-1α) and nuclear factor-erythroid 2-related factor (Nrf2). The imbalance could only be combat by supplementing natural defensive antioxidant enzymes such as superoxide dismutase and catalase. The efficiency of these enzymes is enhanced by use of colloidal carriers which include cellular carriers, vesicular and particulate systems like erythrocytes, leukocytes, platelets, liposomes, transferosomes, solid lipid nanoparticles, microspheres, emulsions. Thus this review provides a platform for understanding importance of antioxidant enzymes and its therapeutic applications in treatment of various autoimmune disorders.

An inflammation-targeting hydrogel for local drug delivery in inflammatory bowel disease

There is a clinical need for new, more effective treatments for chronic and debilitating inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Targeting drugs selectively to the inflamed intestine may improve therapeutic outcomes and minimize systemic toxicity. We report the development of an inflammation-targeting hydrogel (IT-hydrogel) that acts as a drug delivery system to the inflamed colon. Hydrogel microfibers were generated from ascorbyl palmitate, an amphiphile that is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration. IT-hydrogel microfibers loaded with the anti-inflammatory corticosteroid dexamethasone (Dex) were stable, released drug only upon enzymatic digestion, and demonstrated preferential adhesion to inflamed epithelial surfaces in vitro and in two mouse colitis models in vivo. Dex-loaded IT-hydrogel enemas, but not free Dex enemas, administered every other day to mice with colitis resulted in a significant reduction in inflammation and were associated with lower Dex peak serum concentrations and, thus, less systemic drug exposure. Ex vivo analysis of colon tissue samples from patients with ulcerative colitis demonstrated that IT-hydrogel microfibers adhered preferentially to mucosa from inflamed lesions compared with histologically normal sites. The IT-hydrogel drug delivery platform represents a promising approach for targeted enema-based therapies in patients with colonic IBD.

Recent advances in liposome surface modification for oral drug delivery

Oral delivery via the gastrointestinal (GI) tract is the dominant route for drug administration. Orally delivered liposomal carriers can enhance drug solubility and protect the encapsulated theraputic agents from the extreme conditions found in the GI tract. Liposomes, with their fluid lipid bilayer membrane and their nanoscale size, can significantly improve oral absorption. Unfortunately, the clinical applications of conventional liposomes have been hindered due to their poor stability and availability under the harsh conditions typically presented in the GI tract. To overcome this problem, the surface modification of liposomes has been investigated. Although liposome surface modification has been extensively studied for oral drug delivery, no review exists so far that adequately covers this topic. The purpose of this paper is to summarize and critically analyze emerging trends in liposome surface modification for oral drug delivery.

Self assembled hyaluronic acid nanoparticles as a potential carrier for targeting the inflamed intestinal mucosa

To develop a nanoparticulate drug carrier for targeting of the inflamed intestinal mucosa, amphiphilic hyaluronic acid (HA) conjugates were synthesized, which could form self-assembled nanoparticles (NPs) in aqueous solution and budesonide (BDS) was loaded into the HANPs. Their particle sizes were in the range of 177 to 293nm with negative surface charge. The model of inflammatory CACO-2 cells was utilized to investigate the therapeutic potential of budesonide loaded HA nanocarriers. The highest expression of CD44 receptors was found on inflamed Caco-2 cells, as determined by flow cytometry. FITC-labeled HANPs revealed greater uptake in inflamed CACO-2 cells compared to untreated CACO-2 and CD44-negative cell lines, NIH3T3. BDS loaded HANPs displayed almost no toxicity indicating HANPs are excellent biocompatible nano-carriers. BDS loaded HANPs demonstrated higher anti-inflammatory effect on IL-8 and TNF-α secretion in inflamed cell model compared to the same dose of free drug. These results revealed the promising potential of HA nanoparticles as a targeted drug delivery system for IBD treatment.

Emergence of liposome as targeted magic bullet for inflammatory disorders: current state of the art

Inflammatory diseases are considered to be highly dreadful ones responsible for higher mortality in the developed countries. This includes cancer, psoriasis, rheumatoid arthritis, and inflammatory bowel disease. The tremendous strides in the area of drug development to find newer molecules like non-steroidal and steroidal agents and immunosuppressant agents delivered by conventional formulation. These therapy have enhances the life expectancy of patient, but it provide the therapeutic benefits only to a limited extent. Recent advancement in liposomes based nanomedicines has led to the possibility of improves the efficacy and safety of the pharmacotherapy of inflammatory disorders. Of late, liposomes have been highly explored as one of the promising systems for delivering numerous anti-inflammatory drugs for attaining enhanced therapeutic outcomes. Over the conventional carriers, liposomal systems have numerous drug delivery merits including advantages in both passive and active targeting of drug molecules to the inflammatory lesions. The current review article, therefore, endeavors to provide a bird's eye view account on the success of liposome-based therapeutic systems in the management of dreadful inflammatory disorders along with updated knowledge to pharmaceutical scientists in the field.

Size-dependent nanoparticulate drug delivery in inflammatory bowel diseases

INTRODUCTION

Inflammatory bowel disease (IBD) is a chronic autoimmune disease, whose main forms are Crohn's disease and ulcerative colitis. The main treatment of IBD includes oral administration of anti-inflammatory or immunosuppressive agents enclosed in traditional dosage forms, intended to release the active ingredient in the large intestine. However, most of them have been designed based on the physiology of healthy colon, which differs distinctly from conditions met in IBD patients risking adverse effects and patient intolerance. The use of nanoparticles as a drug carrier for treatment of IBD is a promising approach that is capable of solving this problem. Previous studies have shown a size-dependent behavior, where reducing the particle size, increases the targeting efficacy and the residence time compared to healthy controls.

AREAS COVERED

This review covers the utilization of nanoparticles as drug delivery carriers for treating IBD. They can reach the inflamed colonic sites either by endothelial or epithelial delivery employing passive and active targeting strategies. The effect of particle size is analyzed in detail while elucidating other essential parameters such as the particle surface properties.

EXPERT OPINION

One of the most important advantages of nanoparticles is their passive targeting to the inflamed colonic tissues due to their size. Recent findings underline that this size-dependent bioadhesion behavior can be further enhanced by selecting smart surface properties to help in penetrating the mucus and reach the inflamed sites.

Cyclic nitroxide radicals attenuate inflammation and Hyper-responsiveness in a mouse model of allergic asthma

The effects of stable cyclic nitroxide radicals have been extensively investigated both in vivo and in vitro demonstrating anti-inflammatory, radioprotective, anti-mutagenic, age-retardant, hypotensive, anti-cancer and anti-teratogenic activities. Yet, these stable radicals have not been evaluated in asthma and other airway inflammatory disorders. The present study investigated the effect of 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl (TPL) and 3-carbamoyl-proxyl (3-CP) in a mouse model of ovalbumin (OVA)-induced allergic asthma. Both 3-CP and TPL were non-toxic when administered either orally (1% w/w nitroxide-containing chow) or via intraperitoneal (IP) injection (∼300 mg/kg). Feeding the mice orally demonstrated that 3-CP was more effective than TPL in reducing inflammatory cell recruitment into the airway and in suppressing airway hyper-responsiveness (AHR) in OVA-challenged mice. To characterize the optimal time-window of intervention and mode of drug administration, 3-CP was given orally during allergen sensitization, during allergen challenge or during both sensitization and challenge stages, and via IP injection or intranasal instillation for 3 days during the challenge period. 3-CP given via all modes of delivery markedly inhibited OVA-induced airway inflammation, expression of cytokines, AHR and protein nitration of the lung tissue. Oral administration during the entire experiment was the most efficient delivery of 3-CP and was more effective than dexamethasone a potent corticosteroid used for asthma treatment. Under a similar administration regimen (IP injection before the OVA challenge), the effect of 3-CP was similar to that of dexamethasone and even greater on AHR and protein nitration. The protective effect of the nitroxides, which preferentially react with free radicals, in suppressing the increase of main asthmatic inflammatory markers substantiate the key role played by reactive oxygen and nitrogen species in the molecular mechanism of asthma. The present results demonstrate the therapeutic potential of nitroxides for the treatment of asthma.

The anti-inflammatory activity of a novel fused-cyclopentenone phosphonate and its potential in the local treatment of experimental colitis

A novel fused-cyclopentenone phosphonate compound, namely, diethyl 3-nonyl-5-oxo-3,5,6,6a-tetrahydro-1H-cyclopenta[c]furan-4-ylphosphonate (P-5), was prepared and tested in vitro (LPS-activated macrophages) for its cytotoxicity and anti-inflammatory activity and in vivo (DNBS induced rat model) for its potential to ameliorate induced colitis. Specifically, the competence of P-5 to reduce TNFα, IL-6, INFγ, MCP-1, IL-1α, MIP-1α, and RANTES in LPS-activated macrophages was measured. Experimental colitis was quantified in the rat model, macroscopically and by measuring the activity of tissue MPO and iNOS and levels of TNFα and IL-1β. It was found that P-5 decreased the levels of TNFα and the tested proinflammatory cytokines and chemokines in LPS-activated macrophages. In the colitis-induced rat model, P-5 was effective locally in reducing mucosal inflammation. This activity was equal to the activity of local treatment with 5-aminosalicylic acid. It is speculated that P-5 may be used for the local treatment of IBD (e.g., with the aid of colon-specific drug platforms). Its mode of action involves inhibition of the phosphorylation of MAPK ERK but not of p38 and had no effect on IκBα.

Nanomedicines in gastroenterology and hepatology

Nanoscale systems are currently under investigation for multiple different diagnostic and therapeutic applications. These systems can be used to identify pathologically changed tissues or to selectively deliver drugs to these sites; both applications have an extremely high potential to ameliorate therapeutic outcomes for patients. Tissues as well as single cells can be targeted because of the small size of these systems, which enables enhanced diagnosis and increased specificity of therapy. Drug loads can be delivered directly to the site of action, which can result in a reduction in incidence and severity of adverse systemic effects. Several nano-based platform technologies are currently under investigation for use in therapeutic approaches, mainly for anti-inflammatory and anti-cancer therapies. Although many nanoscale systems show promising therapeutic outcomes in preclinical studies, only a limited number are ready for clinical use. This Review will discuss the diverse nanomaterials currently available and the first specific uses for select gastroenterological and hepatological pathologies. The discussion of diagnostic and therapeutic applications will consider realities of market introduction of these sometimes very complex systems in light of remaining regulatory challenges and hurdles for industrial production.

Chemopreventive efficacy of Andrographis paniculata on azoxymethane-induced aberrant colon crypt foci in vivo

Andrographis paniculata is a grass-shaped medicinal herb, traditionally used in Southeast Asia. The aim of this study was to evaluate the chemoprotective effects of A. paniculata on colorectal cancer. A. paniculata ethanol extract was tested on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in vivo and in vitro. A. paniculata treated groups showed a significant reduction in the number of ACF of the treated rats. Microscopically, ACF showed remarkably elongated and stratified cells, and depletion of the submucosal glands of AOM group compared to the treated groups. Histologically, staining showed slightly elevated masses above the surrounding mucosa with oval or slit-like orifices. Immunohistochemically, expression of proliferating cell nuclear antigen (PCNA) and β-catenin protein were down-regulated in the A. paniculata treated groups compared to the AOM group. When colon tissue was homogenized, malondialdehyde (MDA) and nitric oxide (NO) levels were significantly decreased, whereas superoxide dismutase (SOD) activity was increased in the treated groups compared to the AOM group. A. paniculata ethanol extract showed antioxidant and free radical scavenging activity, as elucidated by the measure of oxidative stress markers. Further, the active fractions were assessed against cell lines of CCD841 and HT29 colon cancer cells.

Drug delivery strategies in the therapy of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a frequently occurring disease in young people, which is characterized by a chronic inflammation of the gastrointestinal tract. The therapy of IBD is dominated by the administration of anti-inflammatory and immunosuppressive drugs, which suppress the intestinal inflammatory burden and improve the disease-related symptoms. Established treatment strategies are characterized by a limited therapeutical efficacy and the occurrence of adverse drug reactions. Thus, the development of novel disease-targeted drug delivery strategies is intended for a more effective therapy and demonstrates the potential to address unmet medical needs. This review gives an overview about the established as well as future-oriented drug targeting strategies, including intestine targeting by conventional drug delivery systems (DDS), disease targeted drug delivery by synthetic DDS and disease targeted drug delivery by biological DDS. Furthermore, this review analyses the targeting mechanisms of the respective DDS and discusses the possible field of utilization in IBD.

NANOMATERIALS FOR PROTEIN MEDIATED THERAPY AND DELIVERY

There has been a significant amount of research done on liposomes and nanoparticles as drug carriers for protein drugs. Proteins and enzymes have been used both as targeting moieties and for their therapeutic potential. High specificity and rapid reaction rates make proteins and enzymes excellent candidates for therapeutic treatment, but some limitations exist. Many of these limitations can be addressed by a well studied nanotechnology based delivery system. Such a system can provide a medium for delivery, stabilization of the drugs, and enable site specific accumulation of drugs. Nanomedicines such as these have great potential to revolutionize the pharmaceutical industry and improve healthcare worldwide.

Superoxide dismutase administration, a potential therapy against oxidative stress related diseases: several routes of supplementation and proposal of an original mechanism of action

Oxidative stress, involved in many diseases, is defined as an impaired balance between reactive oxygen species (ROS) production and antioxidant defences. Antioxidant enzymes such as superoxide dismutase (SOD) play a key role in diminishing oxidative stress. Thus, the removal of ROS by exogenous SODs could be an effective preventive strategy against various diseases. The poor bioavailability of exogenous SODs has been criticized. However, improvements in SOD formulation may overcome this limitation and boost interest in its therapeutic properties. Here, we provide a review of animal and human studies about SODs supplementation in order to evaluate their therapeutic value. Protective effects have been observed against irradiation, carcinogenesis, apoptosis and neurodegeneration. SODs administration has also been reported to alleviate inflammatory, infectious, respiratory, metabolic and cardiovascular diseases and genitourinary and fertility disorders, raising the question of its mechanism of action in these diverse situations. Some authors have shown an increase in endogenous antioxidant enzymes after exogenous SODs administration. The induction of endogenous antioxidant defence and, consequently, a decrease in oxidative stress, could explain all the effects observed. Further investigations need to be carried out to test the hypothesis that SODs supplementation acts by inducing an endogenous antioxidant defence.

New targeting strategies in drug therapy of inflammatory bowel disease: mechanistic approaches and opportunities

INTRODUCTION

Inflammatory bowel disease (IBD) is an exceptional scenario with regard to drug targeting, as oral administration has the potential to deliver the drug directly to the site(s) of action. Consequently, retention of the drug within the intestinal lumen and tissue, rather than systemic absorption, is frequently desirable.

AREAS COVERED

In this article, the traditional drug-delivery strategies used in IBD are briefly summarized. These include rectal dosage forms and oral systems that target the lower intestine/colon by pH-, time-, microflora-, and pressure-dependent mechanisms. Then, the article offers an updated overview of recently developed delivery systems aimed to achieve maximal drug concentrations in the inflamed intestinal tissues with minimal systemic side effects. These include antibodies, small molecules, Janus kinase inhibitors, particulate carrier systems, anti-inflammatory peptides, gene therapy, and transgenic bacteria. The various approaches are reviewed, and the challenges that still remain to be overcome are discussed.

EXPERT OPINION

The molecular revolution of the past decade profoundly influenced the treatment and management of IBD. In the coming years, this trend is expected to continue. Yet, many challenges are still ahead. A strong collaborative effort by experts from different fields is encouraged and necessary to maximize our success in IBD drug targeting.

Application of liposomes in drug development--focus on gastroenterological targets

Over the past decade, liposomes became a focal point in developing drug delivery systems. New liposomes, with novel lipid molecules or conjugates, and new formulations opened possibilities for safely and efficiently treating many diseases including cancers. New types of liposomes can prolong circulation time or specifically deliver drugs to therapeutic targets. This article concentrates on current developments in liposome based drug delivery systems for treating diseases of the gastrointestinal tract. We will review different types and uses of liposomes in the development of therapeutics for gastrointestinal diseases including inflammatory bowel diseases and colorectal cancer.

Rivastigmine alleviates experimentally induced colitis in mice and rats by acting at central and peripheral sites to modulate immune responses

The cholinergic anti-inflammatory system and α7 nicotinic receptors in macrophages have been proposed to play a role in neuroimmunomodulation and in the etiology of ulcerative colitis. We investigated the ability of a cholinesterase (ChE) inhibitor rivastigmine, to improve the pathology of ulcerative colitis by increasing the concentration of extracellular acetylcholine in the brain and periphery. In combination with carbachol (10 µM), rivastigmine (1 µM) significantly decreased the release of nitric oxide, TNF-α, IL-1β and IL-6 from lipopolysaccharide-activated RAW 264.7 macrophages and this effect was abolished by α7 nicotinic receptor blockade by bungarotoxin. Rivastigmine (1 mg/kg) but not (0.5 mg/kg), injected subcutaneously once daily in BALB/c mice with colitis induced by 4% dextran sodium sulphate (DSS), reduced the disease activity index (DAI) by 60% and damage to colon structure. Rivastigmine (1 mg/kg) also reduced myeloperoxidase activity and IL-6 by >60%, and the infiltration of CD11b expressing cells by 80%. These effects were accompanied by significantly greater ChE inhibition in cortex, brain stem, plasma and colon than that after 0.5 mg/kg. Co-administration of rivastigmine (1 mg/kg) with the muscarinic antagonist scopolamine significantly increased the number of CD11b expressing cells in the colon but did not change DAI compared to those treated with rivastigmine alone. Rivastigmine 1 and 2 mg given rectally to rats with colitis induced by rectal administration of 30 mg dintrobezene sulfonic acid (DNBS) also caused a dose related reduction in ChE activity in blood and colon, the number of ulcers and area of ulceration, levels of TNF-α and in MPO activity. The study revealed that the ChE inhibitor rivastigmine is able to reduce gastro-intestinal inflammation by actions at various sites at which it preserves ACh. These include ACh released from vagal nerve endings that activates alpha7 nicotinic receptors on circulating macrophages and in brainstem neurons.

Nano- and microparticulate drug carriers for targeting of the inflamed intestinal mucosa

Conventional treatment of inflammatory bowel disease (IBD) is based on the daily administration of high doses of immune-suppressant or anti-inflammatory drugs, often complicated by serious adverse effects. Thus, a carrier system that delivers the drug specifically to the inflamed intestinal regions and shows prolonged drug release would be desirable. The advent of TNF-α antibodies and other biopharmaceuticals as potent and specific immune modulators in recent years has broadened the treatment options in IBD, but further increases the necessity for adequate drug delivery, as integrity and bioactivity of the biological active have to be ensured. Exploiting the pathophysiological idiosyncrasies of IBD such as increased mucus production, changes in the structure of the intestinal epithelium and invasion of activated macrophages, different colloidal drug carrier systems have been designed to passively or actively target the site of inflammation. This review introduces different micro- or nanoparticulate drug delivery systems for oral application in IBD therapy for the delivery of small molecular compounds and next generation therapeutics from the group of biological (i.e. peptide and nucleotide based) drugs.

Enhanced transferrin receptor expression by proinflammatory cytokines in enterocytes as a means for local delivery of drugs to inflamed gut mucosa

Therapeutic intervention in inflammatory bowel diseases (IBDs) is often associated with adverse effects related to drug distribution into non-diseased tissues, a situation which attracts a rational design of a targeted treatment confined to the inflamed mucosa. Upon activation of immune cells, transferrin receptor (TfR) expression increases at their surface. Because TfR is expressed in all cell types we hypothesized that its cell surface levels are regulated also in enterocytes. We, therefore, compared TfR expression in healthy and inflamed human colonic mucosa, as well as healthy and inflamed colonic mucosa of the DNBS-induced rat model. TfR expression was elevated in the colonic mucosa of IBD patients in both the basolateral and apical membranes of the enterocytes. Increased TfR expression was also observed in colonocytes of the induced colitis rats. To explore the underlying mechanism CaCo-2 cells were treated with various proinflammatory cytokines, which increased both TfR expression and transferrin cellular uptake in a mechanism that did not involve hyper proliferation. These findings were then exploited for the design of targetable carrier towards inflamed regions of the colon. Anti-TfR antibodies were conjugated to nano-liposomes. As expected, iron-starved Caco-2 cells internalized anti-TfR immunoliposomes better than controls. Ex vivo binding studies to inflamed mucosa showed that the anti-TfR immunoliposomes accumulated significantly better in the mucosa of DNBS-induced rats than the accumulation of non-specific immunoliposomes. It is concluded that targeting mucosal inflammation can be accomplished by nano-liposomes decorated with anti-TfR due to inflammation-dependent, apical, elevated expression of the receptor.