Alternative drug delivery approaches for the therapy of inflammatory bowel disease

Auranofin-loaded PLGA nanoparticles alleviate cognitive deficit induced by streptozotocin in rats model: modulation of oxidative stress, neuroinflammatory markers, and neurotransmitters

Alzheimer's disease remains an unsolved neurological puzzle with no cure. Current therapies offer only symptomatic relief, hindered by limited uptake through the blood-brain barrier. Auranofin, an FDA-approved compound, exhibits potent antioxidative and anti-inflammatory properties targeting brain disorders. Yet, its oral bioavailability challenge prompts the exploration of nanoformulation-based solutions enhancing blood-brain barrier penetrability. The study aimed to investigate the neuroprotective potential of auranofin nanoparticles in streptozotocin-induced AD rats. Auranofin-containing polylactic-co-glycolic acid nanoparticles were formulated by the multiple emulsion solvent evaporation method. Characterization was done by determining entrapment efficiency, particle size distribution, surface charge, and morphology. An in vivo study was performed by administering streptozotocin (3 mg/kg/i.c.v., days 1 and 3), auranofin (5 and 10 mg/kg), auranofin nanoparticles (2.5 and 5 mg/kg), and donepezil (2 mg/kg) for 14 days orally. Behavioral deficits were evaluated using the open field test, Morris water maze, objective recognition test, change in oxidative stress levels, and AD markers in the brain. Following the decapitation of the rats, the brains were excised to isolate the hippocampus. Subsequent analyses included the quantification of biochemical and neuroinflammatory markers, as well as the assessment of neurotransmitter levels. The characterization of auranofin nanoparticles showed an entrapment efficiency of 98%, an average particle size of 101.5 ± 10.3 nm, a surface charge of 27.5 ± 5.10 mV, and a polydispersity index of 0.438 ± 0.12. In vivo, administration of auranofin and auranofin nanoparticles significantly reversed streptozotocin-induced cognitive deficits, biochemical alteration, neuroinflammatory markers, and neurotransmitter levels. The present finding suggests that auranofin nanoparticles have more significant neuroprotective potential than auranofin alone. The therapeutic efficacy may be attributed to its antioxidant and anti-inflammatory properties, as well as its positive neuromodulatory effects. Therefore, our findings suggest that it could be a promising candidate for Alzheimer's disease therapy.

Aurothioglucose encapsulated nanoparticles fostered neuroprotection in streptozotocin-induced Alzheimer's disease

Alzherimer's disease (AD) is an age-dependent ubiquitous ailment worldwide with limited therapies that only alleviate the symptoms of AD but do not cure them entirely because of the restricted blood-brain barrier passage of the drug. Hence with new advanced technology, nanoparticles can offer an opportunity as the active candidate to overcome the above limitations. Aurothioglucose, a synthetic glucose derivative of the gold compound, has been clinically proven to be an effective anti-inflammatory drug for rheumatic arthritis. Recently, several scientific groups have developed gold nanoparticle preparations and tested them for the treatment of dementia. This study was planned to prepare the PLGA nanoparticles of aurothioglucose (ATG) and check the neuroprotective potential against STZ-induced AD in rats. The nanoparticles were prepared using the double emulsion solvent evaporation method and characterized for various parameters such as drug-excipient interaction, particle size, zeta potential, and morphology. Then, rats were injected STZ (3 mg/kg/i.c.v., days 1 and 3) and ATG (5 and 10 mg/kg/s.c.), ATG NPs (2.5 and 5 mg/kg/s.c.) and donepezil (2 mg/kg/p.o) from 15th to 29th day. Behavior parameters were performed using an actophotometer, MWM, and ORT. On the 30th day, all the animals were sacrificed, and the brains were isolated for estimating biochemical, neurochemical, and proinflammatory markers. It was observed that ATG NPs significantly restored all behavior and neurotransmitter alterations caused by STZ. Also, it increased antioxidant levels and decreased inflammatory cytokines significantly, then ATG alone. Thus, the study suggests that ATG loaded PLGA NPs could be used as a novel therapeutic strategy to slow the process of AD.

Biomedical applications of stimuli-responsive "smart" interpenetrating polymer network hydrogels

In recent years, owing to the ongoing advancements in polymer materials, hydrogels have found increasing applications in the biomedical domain, notably in the realm of stimuli-responsive "smart" hydrogels. Nonetheless, conventional single-network stimuli-responsive "smart" hydrogels frequently exhibit deficiencies, including low mechanical strength, limited biocompatibility, and extended response times. In response, researchers have addressed these challenges by introducing a second network to create stimuli-responsive "smart" Interpenetrating Polymer Network (IPN) hydrogels. The mechanical strength of the material can be significantly improved due to the topological entanglement and physical interactions within the interpenetrating structure. Simultaneously, combining different network structures enhances the biocompatibility and stimulus responsiveness of the gel, endowing it with unique properties such as cell adhesion, conductivity, hemostasis/antioxidation, and color-changing capabilities. This article primarily aims to elucidate the stimulus-inducing factors in stimuli-responsive "smart" IPN hydrogels, the impact of the gels on cell behaviors and their biomedical application range. Additionally, we also offer an in-depth exposition of their categorization, mechanisms, performance characteristics, and related aspects. This review furnishes a comprehensive assessment and outlook for the advancement of stimuli-responsive "smart" IPN hydrogels within the biomedical arena. We believe that, as the biomedical field increasingly demands novel materials featuring improved mechanical properties, robust biocompatibility, and heightened stimulus responsiveness, stimuli-responsive "smart" IPN hydrogels will hold substantial promise for wide-ranging applications in this domain.

Use of Poly Lactic-co-glycolic Acid Nano and Micro Particles in the Delivery of Drugs Modulating Different Phases of Inflammation

Chronic inflammation contributes to the pathogenesis of many diseases, including apparently unrelated conditions such as metabolic disorders, cardiovascular diseases, neurodegenerative diseases, osteoporosis, and tumors, but the use of conventional anti-inflammatory drugs to treat these diseases is generally not very effective given their adverse effects. In addition, some alternative anti-inflammatory medications, such as many natural compounds, have scarce solubility and stability, which are associated with low bioavailability. Therefore, encapsulation within nanoparticles (NPs) may represent an effective strategy to enhance the pharmacological properties of these bioactive molecules, and poly lactic-co-glycolic acid (PLGA) NPs have been widely used because of their high biocompatibility and biodegradability and possibility to finely tune erosion time, hydrophilic/hydrophobic nature, and mechanical properties by acting on the polymer's composition and preparation technique. Many studies have been focused on the use of PLGA-NPs to deliver immunosuppressive treatments for autoimmune and allergic diseases or to elicit protective immune responses, such as in vaccination and cancer immunotherapy. By contrast, this review is focused on the use of PLGA NPs in preclinical in vivo models of other diseases in which a key role is played by chronic inflammation or unbalance between the protective and reparative phases of inflammation, with a particular focus on intestinal bowel disease; cardiovascular, neurodegenerative, osteoarticular, and ocular diseases; and wound healing.

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.

The effect of riboflavin supplementation on the systemic redox status in healthy volunteers: A post-hoc analysis of the RIBOGUT trial

BACKGROUND

Riboflavin is a redox-active vitamin that plays a pivotal role in human energy metabolism. Riboflavin may have beneficial health effects by increasing extracellular antioxidant capacity, thereby alleviating oxidative stress. Reduced levels of free thiols in blood reflect systemic oxidative stress, since they are readily oxidized by reactive species. In this study, we aimed to study the potential of riboflavin supplementation to improve the systemic redox status in healthy volunteers.

METHODS

This study was a post-hoc analysis of the RIBOGUT study, a randomized, double-blind, placebo-controlled human intervention trial that investigated the effect of riboflavin supplements on the gut microbiota composition of healthy individuals. Serum free thiols were quantified before and after intervention and adjusted to serum albumin levels. Changes in albumin-adjusted free thiols were analyzed, as well as potential associations with routine laboratory parameters and faecal bacterial quantification by fluorescence in-situ hybridization (FISH).

RESULTS

Participants were randomized to either placebo (n = 34), riboflavin 50 mg daily (n = 32), or riboflavin 100 mg daily (n = 33). At baseline, no significant differences in albumin-adjusted serum free thiols were observed. After intervention with either placebo or riboflavin, albumin-adjusted serum free thiols did not significantly change (P > 0.05), however, observed changes were inversely associated with changes in C-reactive protein (CRP) levels (r = -0.22, P < 0.05). At baseline, albumin-adjusted serum free thiols were positively associated with faecal relative abundances of Faecalibacterium prausnitzii (P < 0.01).

CONCLUSION

Riboflavin did not change the systemic redox status in healthy individuals as reflected by serum free thiols, but observed changes in albumin-adjusted free thiol levels were negatively associated with changes in CRP levels. Strikingly, albumin-adjusted free thiols were independently associated with relative abundances of faecal F. prausnitzii, which may suggest a potential host redox-microbiota interaction.

Targeted delivery of capecitabine to colon cancer cells using nano polymeric micelles based on beta cyclodextrin

Nano polymeric micelles (nano PMs) help to increase accessibility to tumor sites, decrease side effects and allow controlled drug dissemination over a long period of time. The aim of this study was to optimize the delivery of the anticancer drug capecitabine (CAP) using nano PMs and cyclodextrin (CD) to allow the treatment of colon cancer. A pH-responsive copolymer was prepared and the variables of loading time, loading temperature, the amount of copolymer and also the ratio of acrylic/maleic copolymer to beta CD and the effect that these variables have on drug loading were investigated, with variable optimization studies carried out following a definitive screening design (DSD). The morphology and structure of the particles were determined by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy. In vitro drug release exemplified that the micelles were pH-sensitive, this action was shown that firstly the drug release was done perfectly targeted and under control and secondly the drug has been released above 80% inside the colon.

Nano polymeric micelles (nano PMs) help to increase accessibility to tumor sites, decrease side effects and allow controlled drug dissemination over a long period of time.

Therapeutic Approaches for the Management of Autoimmune Disorders via Gene Therapy: Prospects, Challenges, and Opportunities

BACKGROUND

Autoimmune diseases are the diseases that result due to the overactive immune response, and comprise systemic autoimmune diseases like rheumatoid arthritis (RA), sjӧgren's syndrome (SS), and organ-specific autoimmune diseases like type-1 diabetes mellitus (T1DM), myasthenia gravis (MG), and inflammatory bowel disease (IBD). Currently, there is no long-term cure; but, several treatments exist which retard the evolution of the disease, embracing gene therapy, which has been scrutinized to hold immense aptitude for the management of autoimmune diseases.

OBJECTIVE

The review highlights the pathogenic mechanisms and genes liable for the development of autoimmune diseases, namely T1DM, type-2 diabetes mellitus (T2DM), RA, SS, IBD, and MG. Furthermore, the review focuses on investigating the outcomes of delivering the corrective genes with their specific viral vectors in various animal models experiencing these diseases to determine the effectiveness of gene therapy.

METHODS

Numerous review and research articles emphasizing the tremendous potential of gene therapy in the management of autoimmune diseases were procured from PubMed, MEDLINE, Frontier, and other databases and thoroughly studied for writing this review article.

RESULTS

The various animal models that experienced treatment with gene therapy have displayed regulation in the levels of proinflammatory cytokines, infiltration of lymphocytes, manifestations associated with autoimmune diseases, and maintained equilibrium in the immune response, thereby hinder the progression of autoimmune diseases.

CONCLUSION

Gene therapy has revealed prodigious aptitude in the management of autoimmune diseases in various animal studies, but further investigation is essential to combat the limitations associated with it and before employing it on humans.

Local drug delivery systems for inflammatory diseases: Status quo, challenges, and opportunities

Inflammation that is not resolved in due course becomes a chronic disease. The treatment of chronic inflammatory diseases involves a long-term use of anti-inflammatory drugs such as corticosteroids and nonsteroidal anti-inflammatory drugs, often accompanied by dose-dependent side effects. Local drug delivery systems have been widely explored to reduce their off-target side effects and the medication frequency, with several products making to the market or in development over the years. However, numerous challenges remain, and drug delivery technology is underutilized in some applications. This review showcases local drug delivery systems in different inflammatory diseases, including the targets well-known to drug delivery scientists (e.g., joints, eyes, and teeth) and other applications with untapped opportunities (e.g., sinus, bladder, and colon). In each section, we start with a brief description of the disease and commonly used therapy, introduce local drug delivery systems currently on the market or in the development stage, focusing on polymeric systems, and discuss the remaining challenges and opportunities in future product development.

Oxidative Stress and Redox-Modulating Therapeutics in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is associated with the production of reactive species that target cysteine redox switches in proteins, thereby affecting gene regulation, DNA damage, ion transport, intermediary metabolism, and mitochondrial function. Precursors of reactive species are derived from organic and inorganic compounds and their cofactors, including amino acids, vitamins, oxygen, nitrite, and sulfate. Nutrition and the gut microbiome fuel this process to a significant extent. The production of reactive species in IBD is reflected by a reduction in systemic free thiols, the major components of the antioxidant machinery. Systemic free thiols are amenable to nutritional or therapeutic intervention. This opens up future avenues for therapeutic modulation of redox status in IBD.

Glycyrrhizic acid-loaded pH-sensitive poly-(lactic-co-glycolic acid) nanoparticles for the amelioration of inflammatory bowel disease

Aim: To fabricate and evaluate the therapeutic efficacy of glycyrrhizic acid (GA)-loaded pH-sensitive nanoformulations that specifically target and combat mucosal inflammation of the colon. Methods: GA-loaded Eudragit® S100/poly-(lactic-co-glycolic acid) nanoparticles were developed through modified double-emulsion evaporation coupled with solvent evaporation coating techniques and analyzed for physicochemical characteristics, surface chemistry, release kinetics, site-retention and therapeutic effectiveness. Results: Nanoparticles have a particle size of approximately 200 nm, high encapsulation efficiency, desired surface chemistry with pH-dependent and sustained drug release behavior following the Gompertz kinetic model. In vivo retention and therapeutic effectiveness in the inflamed colon tissues were confirmed by macroscopic and microscopic indices, cytokine analysis and antioxidant assays. Conclusion: GA-loaded Eudragit S100/poly-(lactic-co-glycolic acid) nanoparticles could efficiently deliver GA to the colon and ameliorate the mucosal inflammation for a prolonged duration.

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.

pH-triggered surface charge-reversal nanoparticles alleviate experimental murine colitis via selective accumulation in inflamed colon regions

In this study, we developed pH-triggered surface charge-reversal lipid nanoparticles (LNPs), loaded with budesonide, which could precisely deliver the drug to inflamed colon segments for the treatment of ulcerative colitis. Polyethyleneimine (PEI) was used to render LNPs cationic (PEI-LNPs), and Eudragit® S100 (ES) was coated on PEI-LNPs to obtain pH-triggered charge-reversal LNPs (ES-PEI-LNPs). ES coating avoided a burst drug release under acidic conditions mimicking the stomach and early small intestine environments and showed a sustained release in the colon. The surface charge of ES-PEI-LNPs switched from negative to positive under colonic conditions owing to pH-triggered removal of the ES coating. Bioimaging of the mouse gastrointestinal tract and confocal analysis of colon tissues revealed that ES-PEI-LNPs selectively accumulated in an inflamed colon. Furthermore, ES-PEI-LNPs mitigated experimental colitis in mice. These results suggest that the pH-triggered charge-reversal LNPs could be a promising drug carrier for ulcerative colitis therapy and other colon-targeted treatments.

Bioengineering Bacterially Derived Immunomodulants: A Therapeutic Approach to Inflammatory Bowel Disease

Bacterial enteric pathogens have evolved efficient mechanisms to suppress mammalian inflammatory and immunoregulatory pathways. By exploiting the evolutionary relationship between the gut and pathogenic bacteria, we have developed a potential mucosal therapeutic. Our findings suggest that engineered preparations of the Salmonella acetyltransferase, AvrA, suppress acute inflammatory responses such as those observed in inflammatory bowel disease (IBD). We created 125 nm diameter cross-linked protein nanoparticles directly from AvrA and carrier protein to deliver AvrA in the absence of Salmonella. AvrA nanoparticles are internalized in vitro and in vivo into barrier epithelial and lamina propria monocytic cells. AvrA nanoparticles inhibit inflammatory signaling and confer cytoprotection in vitro, and in murine colitis models, we observe decreased clinical and histological indices of inflammation. Thus, we have combined naturally evolved immunomodulatory proteins with modern bioengineering to produce AvrA nanoparticles, a potential treatment for IBD.

Enzyme sensitive smart inulin-dehydropeptide conjugate self-assembles into nanostructures useful for targeted delivery of ornidazole

Molecular self-assembly of biodegradable amphiphilic polymers allows rational design of biocompatible nanomaterials for drug delivery. Use of substituted polysaccharides for such applications offers the ease of design and synthesis, and provides higher biofunctionality and biocompatibility to nanomaterials. The present work focuses on the synthesis, characterization and potential biomedical applications of self-assembled polysaccharide-based materials. We demonstrated that the synthesized amphiphilic inulin self-assembled in aqueous medium into nanostructures with average size in the range of 146-486nm and encapsulated hydrophobic therapeutic molecule, ornidazole. Hydrophophic dehydropeptide was conjugated with inulin via a biocompatible ester linkage. Dehydrophenylalanine, an unusual amino acid, was incorporated in the peptide to make it stable at a broader range of pH as well as against proteases. The resulting core-shell type of nanostructures could encapsulate ornidazole in the hydrophobic core and released it in a controlled fashion. By taking the advantage of inulin, which gets degraded in the colon by colonic bacteria, the effect of enzyme, inulinase, present in the microflora of the large intestine, on inulin-peptide degradation followed by drug release has been studied. Altogether, small peptide conjugated to inulin offers novel scaffold for the future design of nanostructures with potential applications in the field of targeted drug delivery.

Oral delivery of curcumin via porous polymeric nanoparticles for effective ulcerative colitis therapy

Oral drug delivery has been considered as a promising strategy for ulcerative colitis (UC) therapy. Here, an emulsion solvent evaporation technique was employed to prepare non-porous curcumin (CUR)-loaded polymeric nanoparticles (NPs) and porous CUR-loaded polymeric NPs in the absence or presence of ammonium bicarbonate. The resultant CUR-loaded NPs (non-porous NPs and porous NPs) had a desirable mean particle size of around 260 nm with a narrow size distribution, a uniform pore size distribution, slightly negative-charged surface, high encapsulation efficiency and controlled drug release capacity. In vitro experiments indicated that Raw 264.7 macrophages exhibited time-dependent accumulation profiles of NPs during the initial 2 h of co-incubation. Furthermore, we found that porous NPs inhibited the secretion of the main pro-inflammatory cytokines (TNF-α, IL-6 and IL-12) and the production of reactive oxygen species much more efficiently than non-porous NPs. Most importantly, in vivo studies demonstrated that oral administered porous NPs had a superior therapeutic efficiency in alleviating UC compared with non-porous NPs. The results collectively suggest that porous polymeric NPs can be exploited as efficient oral drug carriers for UC treatment.

Glycoproteins functionalized natural and synthetic polymers for prospective biomedical applications: A review

Glycoproteins have multidimensional properties such as biodegradability, biocompatibility, non-toxicity, antimicrobial and adsorption properties; therefore, they have wide range of applications. They are blended with different polymers such as chitosan, carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), polycaprolactone (PCL), heparin, polystyrene fluorescent nanoparticles (PS-NPs) and carboxyl pullulan (PC) to improve their properties like thermal stability, mechanical properties, resistance to pH, chemical stability and toughness. Considering the versatile charateristics of glycoprotein based polymers, this review sheds light on synthesis and characterization of blends and composites of glycoproteins, with natural and synthetic polymers and their potential applications in biomedical field such as drug delivery system, insulin delivery, antimicrobial wound dressing uses, targeting of cancer cells, development of anticancer vaccines, development of new biopolymers, glycoproteome research, food product and detection of dengue glycoproteins. All the technical scientific issues have been addressed; highlighting the recent advancement.

Recent advances in orally administered cell-specific nanotherapeutics for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing disease in gastrointestinal tract. Conventional medications lack the efficacy to offer complete remission in IBD therapy, and usually associate with serious side effects. Recent studies indicated that nanoparticle-based nanotherapeutics may offer precise and safe alternative to conventional medications via enhanced targeting, sustained drug release, and decreased adverse effects. Here, we reviewed orally cell-specific nanotherapeutics developed in recent years. In addition, the various obstacles for oral drug delivery are also reviewed in this manuscript. Orally administrated cell-specific nanotherapeutics is expected to become a novel therapeutic approach for IBD treatment.

Auranofin-loaded nanoparticles as a new therapeutic tool to fight streptococcal infections

Drug-loaded nanoparticles (NPs) can improve infection treatment by ensuring drug concentration at the right place within the therapeutic window. Poly(lactic-co-glycolic acid) (PLGA) NPs are able to enhance drug localization in target site and to sustainably release the entrapped molecule, reducing the secondary effects caused by systemic antibiotic administration. We have loaded auranofin, a gold compound traditionally used for treatment of rheumatoid arthritis, into PLGA NPs and their efficiency as antibacterial agent against two Gram-positive pathogens, Streptococcus pneumoniae and Streptococcus pyogenes was evaluated. Auranofin-PLGA NPs showed a strong bactericidal effect as cultures of multiresistant pneumococcal strains were practically sterilized after 6 h of treatment with such auranofin-NPs at 0.25 μM. Moreover, this potent bactericidal effect was also observed in S. pneumoniae and S. pyogenes biofilms, where the same concentration of auranofin-NPs was capable of decreasing the bacterial population about 4 logs more than free auranofin. These results were validated using a zebrafish embryo model demonstrating that treatment with auranofin loaded into NPs achieved a noticeable survival against pneumococcal infections. All these approaches displayed a clear superiority of loaded auranofin PLGA nanocarriers compared to free administration of the drug, which supports their potential application for the treatment of streptococcal infections.

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.

Photodynamic therapy relieves colitis and prevents colitis-associated carcinogenesis in mice

BACKGROUND

Inflammatory bowel diseases are incurable illnesses of the gastrointestinal tract, which substantially enhance the risk of developing colorectal carcinogenesis. Conventional photodynamic therapy is a clinically approved therapeutic modality used in the treatment of neoplastic diseases. Recent preclinical and clinical studies have shown that photodynamic therapy with low doses of photosensitizer and/or light improves inflammatory conditions, including colitis. This study aims therefore at investigating the therapeutic potential of low-dose photodynamic therapy (LDPDT) with a liposomal formulation of meta-tetra(hydroxyphenyl)chlorin (namely Foslip) in the prevention of colitis-associated cancer in mice.

METHODS

LDPDT efficacy was evaluated by endoscopic, macroscopic, and histological analysis. Myeloperoxidase levels were quantified by enzyme linked immunosorbent assay and cytokines expression by quantitative RT-PCR analysis. The integrity of the intestinal barrier was evaluated by immunostaining, and bacterial composition of the fecal microbiota was determined by 454 pyrosequencing of V3-V4 region of bacterial 16S rRNA genes.

RESULTS

LDPDT reduced intestinal tumor growth by decreasing the expression of a wide range of inflammatory mediators and by lowering neutrophil influx. LDPDT treatment prevents onset of a dysbiotic microbiota in the colitis-associated cancer model.

CONCLUSIONS

LDPDT with Foslip could be considered as a novel treatment modality to prevent colorectal carcinogenesis in patients with inflammatory bowel disease.

Enzyme/pH dual sensitive polymeric nanoparticles for targeted drug delivery to the inflamed colon

Novel nanoparticles whose drug release profiles are controlled by both enzyme and pH were prepared for the colon-specific drug delivery using a polymeric mixture of enzyme-sensitive azo-polyurethane and pH-sensitive Eudragit S100 (ES-Azo.pu). The enzyme/pH dual sensitive nanoparticles were designed to release a drug based on a two-fold approach which specifically aimed to target drug delivery to the inflamed colon while preventing the burst release of drugs in the stomach and small intestine. Single pH-sensitive (ES) and dual sensitive (ES-Azo.pu) nanoparticles were prepared using an oil-in-water emulsion solvent evaporation method and coumarin-6 (C-6) was used as a model drug. The successful formation of ES and ES-azo.pu nanoparticles that have 214 nm and 244 nm in mean particle size, respectively, was confirmed by scanning electron microscopy and qNano. ES nanoparticles showed almost 100% of burst drug release at pH 7.4, whereas ES-Azo.pu nanoparticles prevented the burst drug release at pH 7.4, followed by a sustained release phase thereafter. Furthermore, ES-Azo.pu nanoparticles exhibited enzyme-triggered drug release in the presence of rat cecal contents obtained from a rat model of colitis. An in vivo localization study in rat gastrointestinal tract demonstrated that ES-Azo.pu nanoparticles were selectively distributed in the inflamed colon, showing 5.5-fold higher C-6 than ES nanoparticles. In conclusion, the enzyme/pH dual sensitive nanoparticles presented in this study can serve as a promising strategy for colon-specific drug delivery against inflammatory bowel disease and other colon disorders.

Nanotechnology in the treatment of inflammatory bowel diseases

BACKGROUND AND AIMS

Treatment of inflammatory bowel diseases (IBD) is only aimed to block or inhibit the pathogenetic steps of the inflammatory cascade. Side effects of systemic therapies, poor targeting of orally administered topical drug and low adherence to prescription represent frequent therapeutic challenges. Recent observations suggest that nanotechnology could provide amazing advantage in this field since particles having dimension in the nanometer scale (nanoparticles) can modify pharmacokinetic step of biologic and conventional therapeutic agents with a better delivery of drugs within the intestinal inflammatory cells. The aim of this review was to provide the clinician with an insight into the potential role of nanotechnology in the treatment of IBD.

METHODS

A systematic search (PubMed) for experimental studies on the treatment of intestinal inflammation using nanotechnology for the delivery of drugs.

RESULTS AND CONCLUSIONS

The size of the pharmaceutical formulation is inversely related to specificity for inflammation. Nanoparticles can penetrate epithelial and inflammatory cells resulting in much higher, effective and long-acting concentrations than can be obtained using conventional delivery systems. From a practical point of view, this should lead to improvements in both efficacy and adherence to treatment, providing patients with the prospect of stable and prolonged remissions with reduced drug loadings. Reduced systemic side effects could also be expected.

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.

Oral colon-specific therapeutic approaches toward treatment of inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease (IBD) is a chronic relapsing idiopathic disease. In clinical terms, most patients require lifelong medication associated with possible unpleasant adverse effects. Oral colon-specific drug delivery systems are designed to deliver therapeutic drugs to the inflamed colon to target pathophysiological manifestations of IBD. The aim is to maintain the drug with proper concentration in the inflamed colon, to enhance drug residence time and to minimize drug absorption by healthy tissues.

AREAS COVERED

This review addresses the main barriers for colon-specific drug delivery from organism, tissue and cell levels, respectively. It also summarizes novel colon-specific therapeutic strategies using microparticles and nanoparticles.

EXPERT OPINION

Oral colon-specific drug delivery represents a possible approach toward efficient treatment of IBD. As the environment of the gastrointestinal tract is harsh and intricate, this approach requires that drug carriers can respond to specific environmental factors of the inflamed colon, permitting stimulus-responsive release of loaded drugs to specific cells or even into specific organelles within cells.

Drug delivery to inflamed colon by nanoparticles: comparison of different strategies

For inflammatory bowel disease (IBD) treatment, local delivery of molecules loaded in nanoparticles to the inflamed colon could be a promising strategy. The aim of this study was to investigate how drug-loaded polymeric nanoparticles target the site of inflammation and to analyse the influence of different colon-specific delivery strategies. Three different polymeric nanoparticles were formulated using ovalbumin (OVA) as a model drug. pH-sensitive nanoparticles were made with Eudragit(®) S100. Mucoadhesive nanoparticles were created with trimethylchitosan (TMC). A mix of polymers, PLGA, PEG-PLGA and PEG-PCL, were used to obtain a sustained drug delivery. Furthermore, ligands targeting immune cells (i.e. mannose) or the inflamed colon (i.e. a specific peptide) were grafted on the PEG chain of PCL. Interaction of nanoparticles with the intestinal epithelium was explored using Caco-2 monolayers designed to mimic an inflamed epithelium and then visualized using confocal laser microscopy. TMC nanoparticles had the highest apparent permeability for OVA in the untreated model. However, in the inflamed model, there were no difference between TMC, PLGA-based and Eudragit(®) nanoparticles. The uptake of nanoparticles in the inflamed mouse colon was assessed in a horizontal diffusion chamber. Mannose-grafted PLGA nanoparticles showed the highest accumulation of OVA in inflamed colon. Based on these results, active targeting of macrophages and dendritic cells may be a promising approach for targeting the colon in IBD.

PLGA-based nanoparticles: an overview of biomedical applications

Poly(lactic-co-glycolic acid) (PLGA) is one of the most successfully developed biodegradable polymers. Among the different polymers developed to formulate polymeric nanoparticles, PLGA has attracted considerable attention due to its attractive properties: (i) biodegradability and biocompatibility, (ii) FDA and European Medicine Agency approval in drug delivery systems for parenteral administration, (iii) well described formulations and methods of production adapted to various types of drugs e.g. hydrophilic or hydrophobic small molecules or macromolecules, (iv) protection of drug from degradation, (v) possibility of sustained release, (vi) possibility to modify surface properties to provide stealthness and/or better interaction with biological materials and (vii) possibility to target nanoparticles to specific organs or cells. This review presents why PLGA has been chosen to design nanoparticles as drug delivery systems in various biomedical applications such as vaccination, cancer, inflammation and other diseases. This review focuses on the understanding of specific characteristics exploited by PLGA-based nanoparticles to target a specific organ or tissue or specific cells.

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.

New formulation of an old drug in hypertension treatment: the sustained release of captopril from cyclodextrin nanoparticles

Captopril (CAP) was the first angiotensin I-converting enzyme (ACE) inhibitor to be developed and is widely used in hypertension treatment. On the other hand, cyclodextrins (CDs) are cyclic oligosaccharides whose cone-shaped cavity allows formation of noncovalent inclusion complexes with appropriately sized guest molecules, thus modifying guest physical, chemical, and biological properties. Herein, the physicochemical characterization and in vivo ACE inhibition evaluation of seven CAP/CD complexes are reported. The inclusion complexes were prepared by spray-drying, freeze-drying, kneading, or lyophilization methods and characterized by nuclear magnetic resonance, Fourier-transformed infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy techniques. In vivo assays compared CAP and CAP/CD complex administration (0.5 mg kg⁻¹ or 0.09 mg kg⁻¹, n = 4–7) to evaluate the ACE inhibition by continuous infusion of angiotensin I (30 ng 50 μL⁻¹ min⁻¹) in conscious Wistar rats. The physicochemical analysis demonstrated complete amorphization and complexation between CAP and CDs, indicating the substitution of water molecules inside the CD cavity with CAP. During the infusion of angiotensin I, the administration of all CAP/CD complexes induced a reduction in mean arterial pressure similar to that observed upon CAP administration. The nanoparticles obtained by the kneading method (CAP/α-CD:KM) showed a potent and long-lasting inhibitory activity (∼22 hours) on the angiotensin I pressor effect. The results suggest that the inclusion complex of CAP and α-CD can function as a novel antihypertensive formulation that may improve therapeutic use of CAP by reducing its oral dose administration to once per day, thus providing better quality of life for almost 25% of the world’s population who suffer from hypertension.

Intestinal delivery of non-viral gene therapeutics: physiological barriers and preclinical models

The future of nucleic acid-based therapeutics is dependent on achieving successful delivery. Recently, there has been an increasing interest in delivery via the gastrointestinal tract. Gene therapy via this route has many advantages, including non-invasive access and the versatility to treat local diseases, such as inflammatory bowel disease, as well as systemic diseases, such as haemophilia. However, the intestine presents several distinct barriers and, therefore, the design of robust non-viral delivery systems is key to future success. Several non-viral delivery strategies have provided evidence of activity in vivo. To facilitate the design of more efficient and safe gene medicines, more physiologically relevant models, at both the in vitro and in vivo levels, are essential.

A three-dimensional coculture of enterocytes, monocytes and dendritic cells to model inflamed intestinal mucosa in vitro

While epithelial cell culture models (e.g., Caco-2 cell line) are widely used to assess the absorption of drug molecules across healthy intestinal mucosa, there are no suitable in vitro models of the intestinal barrier in the state of inflammation. Thus development of novel drugs and formulations for the treatment of inflammatory bowel disease is largely bound to animal models. We here report on the development of a complex in vitro model of the inflamed intestinal mucosa, starting with the selection of suitable enterocyte cell line and proinflammatory stimulus and progressing to the setup and characterization of a three-dimensional coculture of human intestinal epithelial cells and immunocompetent macrophages and dendritic cells. In the 3D setup, controlled inflammation can be induced allowing the mimicking of pathophysiological changes occurring in vivo in the inflamed intestine. Different combinations of proinflammatory stimuli (lipopolysaccharides from Escherichia coli and Salmonella typhimurium, interleukin-1β, interferon-γ) and intestinal epithelial cell lines (Caco-2, HT-29, T84) were evaluated, and only Caco-2 cells were responsive to stimulation, with interleukin-1β being the strongest stimulator. Caco-2 cells responded to the proinflammatory stimulus with a moderate upregulation of proinflammatory markers and a slight, but significant, decrease (20%) of transepithelial electrical resistance (TEER) indicating changes in the epithelial barrier properties. Setting up the coculture model, macrophages and dendritic cells derived from periphery blood monocytes were embedded in a collagen layer on a Transwell filter insert and Caco-2 cells were seeded atop. Even in the presence of immunocompetent cells Caco-2 cells formed a tight monolayer. Addition of IL-1β increased inflammatory cytokine response more strongly compared to Caco-2 single culture and stimulated immunocompetent cells proved to be highly active in sampling apically applied nanoparticles. Thus the 3D coculture provides additional complexity and information compared to the stimulated single cell model. The coculture system may serve as a valuable tool for developing drugs and formulations for the treatment of inflammatory bowel diseases, as well as for studying the interaction of xenobiotics and nanoparticles with the intestinal epithelial barrier in the state of inflammation.

Drug targeting strategies for the treatment of inflammatory bowel disease: a mechanistic update

The therapeutic management of inflammatory bowel disease (IBD) represents the perfect scenario for drug targeting to the site(s) of action. While existing formulation-based targeting strategies include rectal dosage forms and oral systems that target the colon by pH-, time-, microflora- and pressure-triggered drug release, novel approaches for site-specific delivery in IBD therapy will target the inflamed intestine per se rather than intestinal region. The purpose of this article is to present a mechanistic update on the strategies employed to achieve minimal systemic exposure accompanied by maximal drug levels in the inflamed intestinal tissue. The introduction of biological agents, micro/nanoparticulate carriers including liposomes, transgenic bacteria, and gene therapy opportunities are discussed, as well as the challenges remaining to be achieved in the targeted treatment of IBD.

Colorectal cancer chemoprevention by 2 beta-cyclodextrin inclusion compounds of auraptene and 4'-geranyloxyferulic acid

The inhibitory effects of novel prodrugs, inclusion complexes of 3-(4'-geranyloxy-3'-methoxyphenyl)-2-trans propenoic acid (GOFA) and auraptene (AUR) with beta-cyclodextrin (CD), on colon carcinogenesis were investigated using an azoxymethane (AOM)/dextran sodium sulfate (DSS) model. Male CD-1 (ICR) mice initiated with a single intraperitoneal injection of AOM (10 mg/kg body weight) were promoted by the addition of 1.5% (w/v) DSS to their drinking water for 7 days. They were then given a basal diet containing 2 dose levels (100 and 500 ppm) of GOFA/beta-CD or AUR/beta-CD for 15 weeks. At Week 18, the development of colonic adenocarcinoma was significantly inhibited by feeding with GOFA/beta-CD at dose levels of 100 ppm (63% reduction in multiplicity, p < 0.05) and 500 ppm (83% reduction in the multiplicity, p < 0.001), when compared with the AOM/DSS group (multiplicity: 3.36 +/- 3.34). In addition, feeding with 100 and 500 ppm (p < 0.01) of AUR/beta-CD suppressed the development of colonic adenocarcinomas. The dietary administration with GOFA/beta-CD and AUR/beta-CD inhibited colonic inflammation and also modulated proliferation, apoptosis and the expression of several proinflammatory cytokines, such as nuclear factor-kappaB, tumor necrosis factor-alpha, Stat3, NF-E2-related factor 2, interleukin (IL)-6 and IL-1beta, which were induced in the adenocarcinomas. Our findings indicate that GOFA/beta-CD and AUR/beta-CD, especially GOFA/beta-CD, are therefore able to inhibit colitis-related colon carcinogenesis by modulating inflammation, proliferation and the expression of proinflammatory cytokines in mice.