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

Parameters and characteristics governing cellular internalization and trans-barrier trafficking of nanostructures

Cellular internalization and trans-barrier transport of nanoparticles can be manipulated on the basis of the physicochemical and mechanical characteristics of nanoparticles. Research has shown that these factors significantly influence the uptake of nanoparticles. Dictating these characteristics allows for the control of the rate and extent of cellular uptake, as well as delivering the drug-loaded nanosystem intra-cellularly, which is imperative for drugs that require a specific cellular level to exert their effects. Additionally, physicochemical characteristics of the nanoparticles should be optimal for the nanosystem to bypass the natural restricting phenomena of the body and act therapeutically at the targeted site. The factors at the focal point of emerging smart nanomedicines include nanoparticle size, surface charge, shape, hydrophobicity, surface chemistry, and even protein and ligand conjugates. Hence, this review discusses the mechanism of internalization of nanoparticles and ideal nanoparticle characteristics that allow them to evade the biological barriers in order to achieve optimal cellular uptake in different organ systems. Identifying these parameters assists with the progression of nanomedicine as an outstanding vector of pharmaceuticals.

Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: selective targeting to diseased versus healthy tissue

Colon targeted drug delivery is an active area of research for local diseases affecting the colon, as it improves the efficacy of therapeutics and enables localized treatment, which reduces systemic toxicity. Targeted delivery of therapeutics to the colon is particularly advantageous for the treatment of inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease. Advances in oral drug delivery design have significantly improved the bioavailability of drugs to the colon; however in order for a drug to have therapeutic efficacy during disease, considerations must be made for the altered physiology of the gastrointestinal (GI) tract that is associated with GI inflammation. Nanotechnology has been used in oral dosage formulation design as strategies to further enhance uptake into diseased tissue within the colon. This review will describe some of the physiological challenges faced by orally administered delivery systems in IBD, the important developments in orally administered nano-delivery systems for colon targeting, and the future advances of this research.

FROM THE CLINICAL EDITOR

Inflammatory Bowel Disease (IBD) poses a significant problem for a large number of patients worldwide. Current medical therapy mostly aims at suppressing the active inflammatory episodes. In this review article, the authors described and discussed the various approaches current nano-delivery systems can offer in overcoming the limitations of conventional drug formulations.

Fabrication of high specificity hollow mesoporous silica nanoparticles assisted by Eudragit for targeted drug delivery

Hollow mesoporous silica nanoparticles (HMSNs) are one of the most promising carriers for effective drug delivery due to their large surface area, high volume for drug loading and excellent biocompatibility. However, the non-ionic surfactant templated HMSNs often have a broad size distribution and a defective mesoporous structure because of the difficulties involved in controlling the formation and organization of micelles for the growth of silica framework. In this paper, a novel "Eudragit assisted" strategy has been developed to fabricate HMSNs by utilising the Eudragit nanoparticles as cores and to assist in the self-assembly of micelle organisation. Highly dispersed mesoporous silica spheres with intact hollow interiors and through pores on the shell were fabricated. The HMSNs have a high surface area (670 m(2)/g), small diameter (120 nm) and uniform pore size (2.5 nm) that facilitated the effective encapsulation of 5-fluorouracil within HMSNs, achieving a high loading capacity of 194.5 mg(5-FU)/g(HMSNs). The HMSNs were non-cytotoxic to colorectal cancer cells SW480 and can be bioconjugated with Epidermal Growth Factor (EGF) for efficient and specific cell internalization. The high specificity and excellent targeting performance of EGF grafted HMSNs have demonstrated that they can become potential intracellular drug delivery vehicles for colorectal cancers via EGF-EGFR interaction.

Effect of surface chemistry on nanoparticle interaction with gastrointestinal mucus and distribution in the gastrointestinal tract following oral and rectal administration in the mouse

It is believed that mucoadhesive surface properties on particles delivered to the gastrointestinal (GI) tract improve oral absorption or local targeting of various difficult-to-deliver drug classes. To test the effect of nanoparticle mucoadhesion on distribution of nanoparticles in the GI tract, we orally and rectally administered nano- and microparticles that we confirmed possessed surfaces that were either strongly mucoadhesive or non-mucoadhesive. We found that mucoadhesive particles (MAP) aggregated in mucus in the center of the GI lumen, far away from the absorptive epithelium, both in healthy mice and in a mouse model of ulcerative colitis (UC). In striking contrast, water absorption by the GI tract rapidly and uniformly transported non-mucoadhesive mucus-penetrating particles (MPP) to epithelial surfaces, including reaching the surfaces between villi in the small intestine. When using high gavage fluid volumes or injection into ligated intestinal loops, common methods for assessing oral drug and nanoparticle absorption, we found that both MAP and MPP became well-distributed throughout the intestine, indicating that the barrier properties of GI mucus were compromised. In the mouse colorectum, MPP penetrated into mucus in the deeply in-folded surfaces to evenly coat the entire epithelial surface. Moreover, in a mouse model of UC, MPP were transported preferentially into the disrupted, ulcerated tissue. Our results suggest that delivering drugs in non-mucoadhesive MPP is likely to provide enhanced particle distribution, and thus drug delivery, in the GI tract, including to ulcerated tissues.

Clavanin bacterial sepsis control using a novel methacrylate nanocarrier

Controlling human pathogenic bacteria is a worldwide problem due to increasing bacterial resistance. This has prompted a number of studies investigating peptides isolated from marine animals as a possible alternative for control of human pathogen infections. Clavanins are antimicrobial peptides isolated from the marine tunicate Styela clava, showing 23 amino acid residues in length, cationic properties, and also high bactericidal activity. In spite of clear benefits from the use of peptides, currently 95% of peptide properties have limited pharmaceutical applicability, such as low solubility and short half-life in the circulatory system. Here, nanobiotechnology was used to encapsulate clavanin A in order to develop nanoantibiotics against bacterial sepsis. Clavanin was nanostructured using EUDRAGIT^® L 100-55 and RS 30 D solution (3:1 w:w). Atomic force, scanning electron microscopy and dynamic light scattering showed nanoparticles ranging from 120 to 372 nm in diameter, with a zeta potential of -7.16 mV and a polydispersity index of 0.123. Encapsulation rate of 98% was assessed by reversed-phase chromatography. In vitro bioassays showed that the nanostructured clavanin was partially able to control development of Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Furthermore, nanostructures did not show hemolytic activity. In vivo sepsis bioassays were performed using C57BL6 mice strain inoculated with a polymicrobial suspension. Assays led to 100% survival rate under sub-lethal sepsis assays and 40% under lethal sepsis assays in the presence of nanoformulated clavanin A until the seventh day of the experiment. Data here reported indicated that nanostructured clavanin A form shows improved antimicrobial activity and has the potential to be used to treat polymicrobial infections.

Effects of SiO₂, ZrO₂, and BaSO₄ nanomaterials with or without surface functionalization upon 28-day oral exposure to rats

The effects of seven nanomaterials (four amorphous silicon dioxides with or without surface functionalization, two surface-functionalized zirconium dioxides, and barium sulfate) upon 28-day oral exposure to male or female rats were investigated. The studies were performed as limit tests in accordance with OECD Test Guideline 407 applying 1,000 mg test substance/kg body weight/day. Additionally, the acute phase proteins haptoglobin and α2-macroglobulin as well as cardiac troponin I were determined, and metabolome analysis was performed in plasma samples. There were no test substance-related adverse effects for any of the seven nanomaterials. Moreover, metabolomics changes were below the threshold of effects. Since test substance organ burden was not analyzed, it was not possible to establish whether the lack of findings related to the absence of systemic exposure of the tested nanomaterials or if the substances are devoid of any potential for toxicity. The few published subacute oral or short-term inhalation studies investigating comparable nanomaterials (SiO₂, ZrO₂, and BaSO₄) also do not report the occurrence of pronounced treatment-related findings. Overall, the results of the present survey provide a first indication that the tested nanomaterials neither cause local nor systemic effects upon subacute oral administration under the selected experimental conditions. Further investigations should aim at elucidating the extent of gastrointestinal absorption of surface-functionalized nanomaterials.

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.

Utility of models of the gastrointestinal tract for assessment of the digestion and absorption of engineered nanomaterials released from food matrices

Engineered metal/mineral, lipid and biochemical macromolecule nanomaterials (NMs) have potential applications in food. Methodologies for the assessment of NM digestion and bioavailability in the gastrointestinal tract are nascent and require refinement. A working group was tasked by the International Life Sciences Institute NanoRelease Food Additive project to review existing models of the gastrointestinal tract in health and disease, and the utility of these models for the assessment of the uptake of NMs intended for food. Gastrointestinal digestion and absorption could be addressed in a tiered approach using in silico computational models, in vitro non-cellular fluid systems and in vitro cell culture models, after which the necessity of ex vivo organ culture and in vivo animal studies can be considered. Examples of NM quantification in gastrointestinal tract fluids and tissues are emerging; however, few standardized analytical techniques are available. Coupling of these techniques to gastrointestinal models, along with further standardization, will further strengthen methodologies for risk assessment.

pH-sensitive nanoparticles for colonic delivery of curcumin in inflammatory bowel disease

Nano-scaled particles have been found to preferentially accumulate in inflamed regions. Local delivery of anti-inflammatory drugs loaded in nanoparticles to the inflamed colonic site is of great interest for inflammatory bowel disease (IBD) treatment. Curcumin (CC) is an anti-inflammatory local agent, which presents poor ADME properties. Hence, we evaluated, both in vitro and in vivo, the local delivery of CC using pH-sensitive polymeric nanoparticles (NPs) combining both poly(lactide-co-glycolide) acid (PLGA) and a polymethacrylate polymer (Eudragit(®) S100). CC-NPs significantly enhanced CC permeation across Caco-2 cell monolayers when compared to CC in suspension. CC-NPs significantly reduced TNF-α secretion by LPS-activated macrophages (J774 cells). In vivo, CC-NPs significantly decreased neutrophil infiltration and TNF-α secretion while maintaining the colonic structure similar to the control group in a murine DSS-induced colitis model. Our results support the use of nanoparticles made of PLGA and Eudragit(®) S100 combination for CC delivery in IBD treatment.

Interspecies communication between plant and mouse gut host cells through edible plant derived exosome-like nanoparticles

SCOPE

Exosomes, small vesicles participating in intercellular communication, have been extensively studied recently; however, the role of edible plant derived exosomes in interspecies communication has not been investigated. Here, we investigate the biological effects of edible plant derived exosome-like nanoparticles (EPDENs) on mammalian cells.

METHODS AND RESULTS

In this study, exosome-like nanoparticles from four edible plants were isolated and characterized. We show that these EPDENs contain proteins, lipids, and microRNA. EPDENs are taken up by intestinal macrophages and stem cells. The results generated from EPDEN-transfected macrophages indicate that ginger EPDENs preferentially induce the expression of the antioxidation gene, heme oxygenase-1 and the anti-inflammatory cytokine, IL-10; whereas grapefruit, ginger, and carrot EPDENs promote activation of nuclear factor like (erythroid-derived 2). Furthermore, analysis of the intestines of canonical Wnt-reporter mice, i.e. B6.Cg-Tg(BAT-lacZ)3Picc/J mice, revealed that the numbers of β-galactosidase(+) (β-Gal) intestinal crypts are increased, suggesting that EPDEN treatment of mice leads to Wnt-mediated activation of the TCF4 transcription machinery in the crypts.

CONCLUSION

The data suggest a role for EPDEN-mediated interspecies communication by inducing expression of genes for anti-inflammation cytokines, antioxidation, and activation of Wnt signaling, which are crucial for maintaining intestinal homeostasis.

Protective efficacy of ursodeoxycholic acid nanoparticles in animal model of inflammatory bowel disease

Abstract Context: Ursodeoxycholic acid (UDCA) exerts dose-dependent chemoprevention in colonic inflammation. Polycationic UDCA nanoparticles (UNPs) are envisaged for solubility enhancement and site directed drug delivery.

OBJECTIVE

The objective was to study the ameliorative efficacy of UNPs through localized delivery of the drug.

METHODS

UNPs were prepared through nanoprecipitation technique. Particle size, morphology, in vitro drug release and in vivo protective efficacy in inflammatory bowel disease (IBD) of these nanoparticles were studied.

RESULTS AND DISCUSSION

The average particle size was around 100 nm, and the average drug encapsulation was about 99%. In vitro drug release study shows optimal drug release in simulated colonic fluid. The lowering of tissue nitric oxide, malondialdehyde, myeloperoxidase and histology of the colon tissue supported the protective efficacy of the nanoparticles.

CONCLUSION

This study presents the improved efficacy of UNPs in animal model of IBD due to complete release of drug at the desired site of action.

pH-sensitive nanoparticles of curcumin-celecoxib combination: evaluating drug synergy in ulcerative colitis model

Inflammatory bowel diseases, which largely comprise ulcerative colitis (UC) and Crohn's disease, are increasingly posing as a global threat because of the incompetence of the current therapy in the entire patient population. This necessitates the identification of alternative therapeutic molecules or their combinations, which may serve as effective first-line or maintenance therapeutics. In this quest, celecoxib, a selective cyclooxygenase-2 inhibiting nonsteroidal anti-inflammatory agent and curcumin, a natural antioxidant and anti-inflammatory agent, have both been found to be useful in alleviating UC. Furthermore, studies involving their combination have proved synergistic action of these two agents. In the current investigation, we have formulated pH-sensitive nanoparticles of curcumin-celecoxib combination as a potential therapy for UC. Synergistic action of the drug combination, delivery advantages of nanosized carriers, and pH-sensitive nature of the polymer were collectively hypothesized to reduce the overall toxicity and total dose of celecoxib and provide enhanced efficacy for mitigating UC. The hypothesis was confirmed in a UC model in rats, where pH-sensitive nanoparticles of the drug combination were found to be more efficacious than nanoparticles of either drugs or drug/s suspension. Further, the blank nanoparticles did not exhibit any therapeutic effect, thereby confirming efficacy of the drug combination for treating UC.

Harnessing nanomedicine for mucosal theranostics--a silver bullet at last?

Inflammatory bowel disease (IBD) has been extensively studied in the last four decades both in animal models and humans. The treatment options remain disappointing, nonspecific, and associated with multiple systemic adverse effects. In this Perspective, we highlight issues related to emerging nanotechnologies designed particularly for treatment and disease management of IBD and discuss potential therapeutic target options with novel molecular imaging modalities.

In vitro and in vivo evaluation of a water-in-oil microemulsion system for enhanced peptide intestinal delivery

Peptide and protein drugs have become the new generation of therapeutics, yet most of them are only available as injections, and reports on oral local intestinal delivery of peptides and proteins are quite limited. The aim of this work was to develop and evaluate a water-in-oil (w/o) microemulsion system in vitro and in vivo for local intestinal delivery of water-soluble peptides after oral administration. A fluorescent labeled peptide, 5-(and-6)-carboxytetramethylrhodamine labeled HIV transactivator protein TAT (TAMRA-TAT), was used as a model peptide. Water-in-oil microemulsions consisting of Miglyol 812, Capmul MCM, Tween 80, and water were developed and characterized in terms of appearance, viscosity, conductivity, morphology, and particle size analysis. TAMRA-TAT was loaded and its enzymatic stability was assessed in modified simulated intestinal fluid (MSIF) in vitro. In in vivo studies, TAMRA-TAT intestinal distribution was evaluated using fluorescence microscopy after TAMRA-TAT microemulsion, TAMRA-TAT solution, and placebo microemulsion were orally gavaged to mice. The half-life of TAMRA-TAT in microemulsion was enhanced nearly three-fold compared to that in the water solution when challenged by MSIF. The treatment with TAMRA-TAT microemulsion after oral administration resulted in greater fluorescence intensity in all intestine sections (duodenum, jejunum, ileum, and colon) compared to TAMRA-TAT solution or placebo microemulsion. The in vitro and in vivo studies together suggested TAMRA-TAT was better protected in the w/o microemulsion in an enzyme-containing environment, suggesting that the w/o microemulsions developed in this study may serve as a potential delivery vehicle for local intestinal delivery of peptides or proteins after oral administration.