Preparation and characterization of colon-targeted pH/Time-dependent nanoparticles using anionic and cationic polymethacrylate polymers

Targeted and intelligent nano-drug delivery systems for colorectal cancer treatment

Colorectal cancer (CRC) remains a highly heterogeneous malignancy with significant morbidity and mortality worldwide. Despite advancements in surgery, chemotherapy, immunotherapy, and targeted therapy, treatment efficacy is often hampered by drug resistance and systemic toxicity. In recent years, nano-drug delivery systems (NDDS) have emerged as a promising strategy to enhance therapeutic precision, reduce adverse effects, and overcome resistance in CRC treatment. This review discusses the recent advancements in NDDS for CRC treatment, focusing on the optimization of oral drug delivery systems, the development of tumor-specific targeting strategies, and the design of intelligent delivery systems responsive to the tumor microenvironment (TME). Furthermore, we summarize current challenges in NDDS translation and explore future research directions for enhancing their clinical feasibility and therapeutic impact.

Recent insights and applications of nanocarriers-based drug delivery systems for colonic drug delivery and cancer therapy: An updated review

Colorectal cancer (CRC) is the third most prevalent malignant tumor globally and is associated with high morbidity and mortality rates. The advancement of novel nanocarrier-based drug delivery systems has revolutionized therapeutic strategies for colonic drug delivery and cancer treatment. This review provides updated insights into various nanocarrier technologies, including quantum dots (QDs), polymeric nanoparticles (PNPs), magnetic and metallic nanoparticles, solid lipid nanoparticles (SLNs), and self-microemulsifying and self-nanoemulsifying drug delivery systems (SMEDDS/SNEDDS). These nanocarriers offer enhanced drug stability, controlled release, and targeted delivery, particularly for CRC treatment, resulting in up to 70 % improved therapeutic efficacy and a significant reduction in systemic toxicity as reported in preclinical studies. The review comprehensively discusses the structural composition, mechanisms of action, therapeutic potential, and imaging capabilities of these systems, with a focus on their applications in theranostics and targeted CRC therapy. For instance, polymeric nanoparticles have demonstrated a 50 % increase in bioavailability compared to conventional formulations, while QDs have enabled real-time imaging with high precision for tumor localization. Additionally, the toxicity profiles and challenges associated with these nanocarriers are critically evaluated. Despite significant progress in preclinical and clinical studies, the review highlights the need for optimizing biocompatibility, scalability, and regulatory standards to facilitate the clinical translation of these promising technologies. Emerging formulations such as graphene quantum dots and PEGylated nanoparticles have shown potential for achieving dual therapeutic and diagnostic applications with fewer adverse effects. Overall, nanocarrier-based systems hold great potential for personalized and more effective treatments in colon-targeted therapies.

The Effect of the Size of Gold Nanoparticle Contrast Agents on CT Imaging of the Gastrointestinal Tract and Inflammatory Bowel Disease

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD). CT imaging with contrast agents is commonly used for visualizing the gastrointestinal (GI) tract in UC patients. Contrast agents that provide enhanced imaging performance are highly valuable in this field. Recent studies have made significant progress in developing better contrast agents for imaging the gastrointestinal tract using nanoparticles. However, the impact of nanoparticle size on this application remains unexplored. Gold nanoparticles (AuNPs) serve as an ideal model to investigate the effect of nanoparticle size on imaging of the gastrointestinal tract due to their controllable synthesis across a broad size range. In this study, we synthesized AuNPs with core sizes ranging from 5 to 75 nm to examine the effect of the size in this setting. AuNPs were coated with poly(ethylene glycol) (PEG) to enhance stability and biocompatibility. In vitro tests show that gold nanoparticles are cytocompatible with macrophage cells (∼100% cell viability) and remain stable under acidic conditions, with no significant size changes over time. Phantom imaging studies using a clinical CT scanner indicated that there was no effect of nanoparticle size on CT contrast production, as previously demonstrated. In vivo imaging using a mouse model of acute colitis revealed a strong contrast generation throughout the GI tract for all agents tested. For the most part, in vivo contrast was independent of AuNP size, although AuNP outperformed iopamidol (a clinically approved control agent). In addition, differences in attenuation trends were observed between healthy and colitis mice. We also observed almost complete clearance at 24 h of all formulations tested (less than 0.7% ID/g was retained), supporting their value as a model platform for studying nanoparticle behavior in imaging. In conclusion, this study highlights the potential of nanoparticles as effective contrast agents for CT imaging of the gastrointestinal tract (GIT) in the UC. Further systemic research is needed to explore contrast agents that can specifically image disease processes in this disease setting.

pH-Dependent Drug Delivery Systems for Ulcerative Colitis Treatment

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

Characterization of Interpolyelectrolyte Complexes Based on Eudragit® RL and Oppositely Charged Eudragit® Polyanions as a Novel Matrix System for Colon-specific Drug Delivery

The design of new interpolyelectrolyte complexes (IPEC) between Eudragit® polycation (type RL) and oppositely charged Eudragit® polyanions (types L100-55, L100, S100, FS) was investigated. The formation and chemical composition of novel IPECs between countercharged Eudragit® copolymers was established by gravimetric and elemental analysis. The structure and solid state properties of the synthesized IPEC were investigated comparatively to correspondent physical mixtures pairs of copolymers in similar molar ratio, using Fourier transform infrared (FTIR) spectroscopy and modulated temperature differential scanning calorimetry (mDSC). The binding ratio of a unit molecule of RL with polyanions was found to range between 1.73:1 and 4.19:1 while increasing the percentages of carboxylic groups in their structures from 10% (FS) to 50% (L100-55). As a result of electrostatic interaction between the copolymer chains, the glass transition temperature of the IPEC changed significantly. Considerable pH-sensitive swelling in acidic and neutral media was observed for different type of IPECs. Through evaluation of diffusion-transportation properties of the IPECs, basic mechanisms controlling the delivery of indomethacin were obtained. The results of swelling and release of the model drug from the polycomplex matrices confirm that they have potential to be used in colon-specific drug delivery.

Effect of gelatin nanoparticles' size and charge on iontophoretic targeted deposition to the hair follicles

Hair follicles (HFs) represent a route of interest to drug delivery for treating several skin conditions. Iontophoresis, on the other hand, is a physical method to enhance drug permeation by applying a low electrical current to the formulation. HFs can be targeted following topical iontophoretic application, as they represent a pathway of lower electrical resistance, as well as a drug reservoir, in particular useful for nanoparticles (NPs), which can preferably accumulate in these structures. Combining both strategies may provide optimal results, but the literature still lacks evidence of the ideal NP characteristics for the iontophoretic drug delivery targeting the HFs. Here, we aimed to evaluate the effect of gelatin NPs' size and charge under iontophoresis application on NPs' deposition into the HFs. Four gelatin NP formulations were produced with varying gelatin concentrations and gelatin types (positively charged type A and negatively charged type B), with sizes ranging from 220 to 770 nm. A fluorescent dye, TRITC-dextran 150 kDa, was encapsulated for monitoring NPs deposition. Cutaneous penetration experiments were performed in vitro with and without iontophoresis for 6 h with pig ear skin. The deposition profile was assessed by confocal laser scanning microscopy. Photomicrographs showed a higher accumulation of the larger positively charged NPs (AL), reaching deeper portions of HFs, and showed iontophoresis further increased their deposition, resulting in the highest signal. In conclusion, these findings shed light on the applications of NPs and bring novel treatment opportunities for several diseases compromising the hair follicles.

Advancements in Inflammatory Bowel Disease Management: From Traditional Treatments to Monoclonal Antibodies and Future Drug Delivery Systems

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disorder with two main subtypes: ulcerative colitis (UC) and Crohn's disease (CD). The pathogenesis involves genetic predisposition, dysbiosis, and immune dysregulation. Complications include perianal lesions, strictures, fistulas, perforations, and an increased risk of colon cancer. Clinical classification ranges from mild to fulminant and recurrent disease, with common symptoms such as abdominal discomfort, rectal bleeding, diarrhea, and weight loss. Extraintestinal manifestations include arthritis, erythema nodosum, pyoderma gangrenosum, and uveitis. Conventional treatments using aminosalicylates, corticosteroids, and immunomodulators have limitations. Biologics, introduced in the 1990s, offer improved efficacy and specificity, targeting factors like TNF-α, integrins, and cytokines. Monoclonal antibodies play a crucial role in IBD management, aiming to reduce relapses, hospitalizations, and surgeries. In conclusion, this review is aimed at summarizing the latest knowledge, advantages, and drawbacks of IBD therapies, such as small molecules, biologics, and monoclonal antibodies, to provide a basis for further research in the IBD field.

Leucaena leucocephala succinate based polyelectrolyte complexes for colon delivery of synbiotic in management of inflammatory bowel disease

Polyelectrolyte complexes (PECs) formed by the interaction between oppositely charged polymers have emerged as promising carriers for accomplishing colon-specific release. In this study, we have explored the potential of polyelectrolyte complexes between a succinate derivative of Leucaena leucocephala galactomannan and cationic guar gum for colon delivery of synbiotic. The PECs were prepared using a polyelectrolyte complexation method and characterized. The PECs exhibited excellent stability, with high encapsulation efficiency for both probiotics (95.53 %) and prebiotics (83.33 %). In vitro studies demonstrated enhanced survivability and proliferation of the encapsulated probiotics in the presence of prebiotics (93.29 %). The SEM images revealed a smooth and firm structure with reduced number of pores when both prebiotic and probiotic were encapsulated together. The treatment with synbiotic PECs in acetic acid induced IBD rats significantly relieves colitis symptoms as was evident from colon/body ratio, DAI score and histopathology studies. An increase in the protein and reduced glutathione levels and reduction in superoxide dismutase activity was observed in colitic rats that received synbiotic treatment as compared to colitic rats. Overall, this study highlights the potential of Leucaena leucocephala succinate-cationic guar gum PECs as a promising system for colon-specific synbiotic delivery, with implications for improved gut health and the treatment of various gastrointestinal disorders.

Targeting the Gut: A Systematic Review of Specific Drug Nanocarriers

The intestine is essential for the modulation of nutrient absorption and the removal of waste. Gut pathologies, such as cancer, inflammatory bowel diseases (IBD), irritable bowel syndrome (IBS), and celiac disease, which extensively impact gut functions, are thus critical for human health. Targeted drug delivery is essential to tackle these diseases, improve therapy efficacy, and minimize side effects. Recent strategies have taken advantage of both active and passive nanocarriers, which are designed to protect the drug until it reaches the correct delivery site and to modulate drug release via the use of different physical-chemical strategies. In this systematic review, we present a literature overview of the different nanocarriers used for drug delivery in a set of chronic intestinal pathologies, highlighting the rationale behind the controlled release of intestinal therapies. The overall aim is to provide the reader with useful information on the current approaches for gut targeting in novel therapeutic strategies.

Study of PEG-b-PLA/Eudragit S100 Blends on the Nanoencapsulation of Indigo Carmine Dye and Application in Controlled Release

A nanocapsule shell of poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) mixed with anionic Eudragit S100 (90/10% w/w) was previously used to entrap and define the self-assembly of indigo carmine (IC) within the hydrophilic cavity core. In the present work, binary blends were prepared by solution mixing at different PEG-b-PLA/Eudragit S100 ratios (namely, 100/0, 90/10, 75/25, and 50/50% w/w) to elucidate the role of the capsule shell in tuning the encapsulation of the anionic dye (i.e., IC). The results showed that the higher content of Eudragit S100 in the blend decreases the miscibility of the two polymers due to weak intermolecular interactions between PEG-b-PLA and Eudragit S100. Moreover, with an increase in the amount of Eudragit S100, a higher thermal stability was observed related to the mobility restriction of PEG-b-PLA chains imposed by Eudragit S100. Formulations containing 10 and 25% Eudragit S100 exhibited an optimal interplay of properties between the negative surface charge and the miscibility of the polymer blend. Therefore, the anionic character of the encapsulating agent provides sufficient accumulation of IC molecules in the nanocapsule core, leading to dye aggregates following the self-assembly. At the same time, the blending of the two polymers tunes the IC release properties in the initial stage, achieving slow and controlled release. These findings give important insights into the rational design of polymeric nanosystems containing organic dyes for biomedical applications.

Fexofenadine-loaded chitosan coated solid lipid nanoparticles (SLNs): A potential oral therapy for ulcerative colitis

The targeting and mucoadhesive features of chitosan (CS)-linked solid lipid nanoparticles (SLNs) were exploited to efficiently deliver fexofenadine (FEX) into the colon, forming a novel and potential oral therapeutic option for ulcerative colitis (UC) treatment. Different FEX-CS-SLNs with varied molecular weights of CS were prepared and optimized. Optimized FEX-CS-SLNs exhibited 229 ± 6.08 nm nanometric size, 36.3 ± 3.18 mV zeta potential, 64.9 % EE, and a controlled release profile. FTIR, DSC, and TEM confirmed good drug entrapment and spherical particles. Mucoadhesive properties of FEX-CS-SLNs were investigated through mucin incubation and exhibited considerable mucoadhesion. The protective effect of FEX-pure, FEX-market, and FEX-CS-SLNs against acetic acid-induced ulcerative colitis in rats was examined. Oral administration of FEX-CS-SLNs for 14 days before ulcerative colitis induction reversed UC symptoms and almost restored the intestinal mucosa to normal integrity and inhibited Phosphatidylinositol-3 kinase (73.6 %), protein kinase B (73.28 %), and elevated nuclear factor erythroid 2-related factor 2 (185.9 %) in colonic tissue. Additionally, FEX-CS-SLNs inhibited tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) to (70.79 % & 72.99 %) in colonic tissue. The ameliorative potential of FEX-CS-SLNs outperformed that of FEX-pure and FEX-market. The exceptional protective effect of FEX-CS-SLNs makes it a potentially effective oral system for managing ulcerative colitis.

Targeted delivery of budesonide in acetic acid induced colitis: impact on miR-21 and E-cadherin expression

Inflammatory bowel disease (IBD) is characterized by chronic inflammation along the gastrointestinal tract. For IBD effective treatment, developing an orally administered stable drug delivery system capable of targeting inflammation sites is a key challenge. Herein, we report pH responsive hyaluronic (HA) coated Eudragit S100 (ES) nanoparticles (NPs) for the targeted delivery of budesonide (BUD) (HA-BUD-ES-NPs). HA-BUD-ES-NPs showed good colloidal properties (274.8 ± 2.9 nm and - 24.6 ± 2.8 mV) with high entrapment efficiency (98.3 ± 3.41%) and pH-dependent release profile. The negative potential following incubation in simulated gastrointestinal fluids reflected the stability of HA coat. In vitro studies on Caco-2 cells showed HA-BUD-ES-NPs biocompatibility and enhanced cellular uptake and anti-inflammatory effects as shown by the significant reduction in IL-8 and TNF-α. The oral administration of HA-BUD-ES-NPs in an acetic acid induced colitis rat model significantly mitigated the symptoms of IBD, and improved BUD therapeutic efficacy compared to drug suspension. This was proved via the improvement in disease activity index and ulcer score in addition to refined histopathological findings. Also, the assessment of inflammatory markers, epithelial cadherin, and mi-R21 all reflected the higher efficiency of HA-BUD-ES-NPs compared to free drug and uncoated formulation. We thus suggest that HA-BUD-ES-NPs provide a promising drug delivery platform for the management and site specific treatment of IBD.

Tri-Layer Core-Shell Fibers from Coaxial Electrospinning for a Modified Release of Metronidazole

Polymers are the backbone of drug delivery. Electrospinning has greatly enriched the strategies that have been explored for developing novel drug delivery systems using polymers during the past two decades. In this study, four different kinds of polymers, i.e., the water-soluble polymer poly (vinyl alcohol) (PVA), the insoluble polymer poly(ε-caprolactone) (PCL), the insoluble polymer Eudragit RL100 (ERL100) and the pH-sensitive polymer Eudragit S100 (ES100) were successfully converted into types of tri-layer tri-polymer core-shell fibers through bi-fluid coaxial electrospinning. During the coaxial process, the model drug metronidazole (MTD) was loaded into the shell working fluid, which was an emulsion. The micro-formation mechanism of the tri-layer core-shell fibers from the coaxial emulsion electrospinning was proposed. Scanning electron microscope and transmission electron microscope evaluations verified the linear morphology of the resultant fibers and their obvious tri-layer multiple-chamber structures. X-ray diffraction and Fourier transform infrared spectroscopy measurements demonstrated that the drug MTD presented in the fibers in an amorphous state and was compatible with the three polymeric matrices. In vitro dissolution tests verified that the three kinds of polymer could act in a synergistic manner for a prolonged sustained-release profile of MTD in the gut. The drug controlled-release mechanisms were suggested in detail. The protocols reported here pioneer a new route for creating a tri-layer core-shell structure from both aqueous and organic solvents, and a new strategy for developing advanced drug delivery systems with sophisticated drug controlled-release profiles.

Can histamine cause an enhancement of the cellular uptake and cytotoxicity of doxorubicin-loaded polylactide nanoparticles?

Histamine (His) in humans is physiologically involved in neurotransmission and increases vascular permeability during the development of inflammatory response and immunity. It could be used to enhance drug-loaded nanoparticles (NPs) distribution. However, it cannot be freely delivered due to the risk of His-dose-dependent deleterious effects. His can be attached to the polymeric backbone during polymerization to overcome this limitation. In this study, His was used as an initiator of lactide polymerization, and the obtained macromolecules were subsequently used to prepare doxorubicin (DOX)-loaded NPs by nanoprecipitation and microfluidics for examination of anti-cancer properties. Notably, the in vitro activity towards gastric cancer cells (AGS) of the NPs composed of histamine-functionalized polylactides (PLAs) was greatly enhanced compared to control NPs built from hydroxy‑functionalized PLAs. Furthermore, Zonula occludens-1 (ZO-1) tight junction protein production was significantly diminished after treating cells with DOX-loaded NPs assembled with PLAs with histamine residues. These results demonstrate the synergistic effect in cytotoxicity towards gastric cancer cells of DOX and the histamine that are carried by NPs. It is believed that His-DOX NPs strategy may lead to effective, targeted, and low-toxic delivery of drugs into cancer cells.

Potential applications of drug delivery technologies against radiation enteritis

INTRODUCTION

The incidence of abdominal tumors, such as colorectal and prostate cancers, continually increases. Radiation therapy is widely applied in the clinical treatment of patients with abdominal/pelvic cancers, but it often unfortunately causes radiation enteritis (RE) involving the intestine, colon, and rectum. However, there is a lack of suitable treatment options for effective prevention and treatment of RE.

AREAS COVERED

Conventional clinical drugs for preventing and treating RE are usually applied by enemas and oral administration. Innovative gut-targeted drug delivery systems including hydrogels, microspheres, and nanoparticles are proposed to improve the prevention and curation of RE.

EXPERT OPINION

The prevention and treatment of RE have not attracted sufficient attention in the clinical practice, especially compared to the treatment of tumors, although RE takes patients great pains. Drug delivery to the pathological sites of RE is a huge challenge. The short retention and weak targeting of conventional drug delivery systems affect the therapeutic efficiency of anti-RE drugs. Novel drug delivery systems including hydrogels, microspheres, and nanoparticles can allow drugs long-term retention in the gut and targeting the inflammation sites to alleviate radiation-induced injury.

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.

Orally Dispersible Dosage Forms for Paediatric Use: Current Knowledge and Development of Nanostructure-Based Formulations

The paediatric population has always suffered from a lack of medicines tailored to their needs, especially in terms of accurate dosage, stability and acceptability. Orodispersible dosage forms have gone through a resurrection as an alternative to liquid formulations or fractioned solid formulations, although they are still subject to several inconveniences, among which the unpleasant taste and the low oral bioavailability of the API are the most significant hurdles in the way of achieving an optimal drug product. Nanostructures can address these inconveniences through their size and variety, owing to the plethora of materials that can be used in their manufacturing. Through the formation and functionalisation of nanostructures, followed by their inclusion in orodispersible dosage forms, safe, stable and acceptable medicines intended for paediatric use can be developed.

Polymeric Coatings and Antimicrobial Peptides as Efficient Systems for Treating Implantable Medical Devices Associated-Infections

Many infections are associated with the use of implantable medical devices. The excessive utilization of antibiotic treatment has resulted in the development of antimicrobial resistance. Consequently, scientists have recently focused on conceiving new ways for treating infections with a longer duration of action and minimum environmental toxicity. One approach in infection control is based on the development of antimicrobial coatings based on polymers and antimicrobial peptides, also termed as “natural antibiotics”.

Nanotechnology-Based Drug Delivery System for Anticancer Active Ingredients from Traditional Chinese Medicines: A Review

The variable dosage forms of most traditional Chinese medicines (TCMs) could be disadvantaged by low selectivity, poor biological distribution, limited bioavailability with low efficacy, and some adverse effects. These issues limit the control of clinical pharmacodynamics of the antitumor active components. With the progress of science and technology, many new polymer materials and new technologies have emerged, such as nanotechnology, cyclodextrin inclusion, solid dispersion, microcapsule and microsphere technologies. These new technologies provide a good basis for exploring novel TCM dosage forms for overcoming the shortcomings. The increased numbers of new technologies have been used to study TCM dosage forms with remarkable achievements. In this review paper, we will provide a systematic overview of the new dosage forms of nano-formulations and co-medications in relation to nano-delivery systems in an attempt to provide useful references for practical application of active antitumor ingredients from the TCMs.