The pharmacokinetics (PK) of oral drug compounds are often significantly altered by food intake and evaluating this effect, as required by regulatory agencies, typically involves costly and time-consuming clinical trials. This study used the Dynamic Gastrointestinal Model (DGM), an advanced in vitro system simulating both biochemical and mechanical aspects of the human upper gastrointestinal tract, to predict plasma concentration-time profiles (PK profiles) and food effect of three immediate release oral drug products. The drug products, containing cinnarizine (CIN), diclofenac potassium (DIC) or paracetamol (PAR), were processed in the DGM mimicking the fasted and fed state clinical protocols and the resulting intestinal drug dissolution profiles were modelled (by convolution) to achieve the predicted PK profiles. The predicted PK profiles in both the fasted and fed state were in accordance with the observations in clinical trials, capturing both the positive food effect for CIN and the negative food effects for DIC and PAR. These findings demonstrate the ability of the DGM to provide insights into the PK performance and food effect of oral drug products.

The oral delivery of DNA/RNA nanoparticles represents a transformative approach in immunotherapy and vaccine development. These nanoparticles enable targeted immune modulation by delivering genetic material to specific cells in the gut-associated immune system, triggering both mucosal and systemic immune responses. Unlike parenteral administration, the oral route offers a unique immunological environment that supports both tolerance and activation, depending on the formulation design. This review explores the underlying mechanisms of immune modulation by DNA/RNA nanoparticles, their design and delivery strategies, and recent advances in their application. Emphasis is placed on strategies to overcome physiological barriers such as acidic pH, enzymatic degradation, mucus entrapment, and epithelial tight junctions. Special attention is given to the role of gut-associated lymphoid tissue in mediating immune responses and the therapeutic potential of these systems in oral vaccine platforms, food allergies, autoimmune diseases, and chronic inflammation. Despite challenges, recent advances in nanoparticle formulation support the translation of these technologies into clinical applications for both therapeutic immunomodulation and vaccination.

Understanding and exploiting bioelectric signaling pathways and physicochemical properties of materials that interface with living tissues is central to advancing tissue regeneration. In particular, the emerging field of bioelectronics leverages these principles to develop personalized, minimally invasive therapeutic strategies tailored to the dynamic demands of individual patients. By integrating sensing and actuation modules into flexible, biocompatible devices, clinicians can continuously monitor and modulate local electrical microenvironments, thereby guiding regenerative processes without extensive surgical interventions. This review provides a critical examination of how fundamental bioelectric cues and physicochemical considerations drive the design and engineering of next-generation bioelectronic platforms. These platforms not only promote the formation and maturation of new tissues across neural, cardiac, musculoskeletal, skin, and gastrointestinal systems but also precisely align therapies with the unique structural, functional, and electrophysiological characteristics of each tissue type. Collectively, these insights and innovations represent a convergence of biology, electronics, and materials science that holds tremendous promise for enhancing the efficacy, specificity, and long-term stability of regenerative treatments, ushering in a new era of advanced tissue engineering and patient-centered regenerative medicine.

The objective of this study was to develop a scheme to predict intestinal and plasma concentration-time profiles of the weakly basic BCS-II drug, dipyridamole (DPD), using an Artificial Gut Simulator (AGS) integrated with a compartment-based disposition model. In vivo data for this study was obtained from previously published literature. A 3-compartment disposition model was developed using the plasma concentration-time profile of DPD following an intravenous bolus dose. The AGS, consisting of a donor cell and a hollow fiber-based absorption module, was tuned to absorb DPD saturated solution at a physiological rate constant, 0.0402 min-1, based on the measured Caco-2 cell monolayer permeability coefficient. The dose dumping technique commonly used during dissolution testing can generate excessively high initial supersaturation and precipitation which is not physiologically relevant. In this study, fractions of DPD dose were added incrementally every 15 min to the AGS donor to simulate an overall first-order gastric emptying process. The concentration absorbed by the hollow fiber receiver media was input into the central compartment of the disposition model. The predicted plasma concentration-time profile matched the human in vivo profile of DPD obtained after oral administration of a 50 mg dose. For 30 and 90 mg oral doses, time profiles of concentration and fraction precipitated in the AGS donor agreed well with human duodenal measurements. This study demonstrates the significance of simulating physiological rate of absorption in vitro to accurately predict the bioavailability of a BCS-II compound.

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.

The gut microbiome is recognized as a critical factor in advancing precision nutrition and medicine for health and in developing dietary recommendations and targeted therapies for gastrointestinal (GI) health and diseases. However, conventional sampling methods, such as fecal analysis and colonoscopy, often fail to capture microbial information from specific regions of the GI tract or require invasive procedures, thereby limiting accuracy and clinical utility. As a non-invasive alternative, passive sampling capsules have been developed for site-specific microbiome analysis by employing pH-sensitive enteric coatings that delay sampling until the capsule reaches the targeted intestinal region. Although this approach has been successful in the small intestine, colonic sampling remains challenging due to the high interpersonal variability in intestinal pH, which makes it difficult to rely solely on a pH-triggering mechanism. To overcome this challenge, a dual bacterially and pH triggered polymeric enteric coating was created by blending lactulose and N,N-dimethylaminoethyl methacrylate, enabling complete dissolution within the colonic region. Through systematic characterization of multiple polymer blend compositions using Fourier Transform Infrared Spectroscopy, Thermogravimetric Analysis, and Differential Scanning Calorimetry, an optimized design was identified that provides both suitable physical integrity and rapid (∼2 h) degradation in the presence of colonic bacteria, across a pH range of 5 to 8. The optimized blend was subsequently applied as a double-layer enteric coating on a sampling capsule, enabling the dissolution of the outer layer in the small intestine and complete dissolution of the inner layer in the colon. In-vitro and in-vivo pig model studies were conducted to validate the capsule's sampling performance and to ensure the preservation of the microbial environment. Furthermore, 16S rRNA sequencing revealed a taxonomic similarity between samples collected by the capsule and the colonic microbiome (residing between the ileum and fecal matter). Overall, this technology provides an effective approach to targeted microbial sampling and may pave the way for more comprehensive colonic microbiome analyses and improved diagnostic capabilities for GI diseases. STATEMENT OF SIGNIFICANCE: Precise monitoring of the gut microbiome is vital for understanding health and disease, yet current sampling techniques often lack precision or require invasive procedures. Our work introduces a novel, non-invasive capsule that targets the colon using a dual-trigger polymer system activated by both pH and colonic bacteria. This design enables localized sampling of gut microbiota, overcoming the limitations of fecal analysis, endoscopy, and earlier pH-triggered capsule designs. By capturing microbial communities directly from the colon, our technology provides deeper insights into colonic health and conditions such as inflammatory bowel disease and colorectal cancer. This breakthrough represents a significant advancement in precision nutrition and medicine for human health, and advanced diagnostics and targeted therapies to support dietary guidance, clinical practice and biomedical research.

The invasive nature of sample collection for studying the small intestinal (SI) microbiome often results in its poor characterization. This study evaluated a novel ingestible medical device (MD) for SI luminal sample collection. A monocentric interventional trial (NCT05477069) was conducted on 15 healthy subjects. Metagenomics, metabolomics and culturomics assessed the MD's effectiveness in characterizing the healthy SI microbiome and identifying potential biomarkers. The SI microbiota differed significantly from the fecal microbiota, displaying high inter-individual variability, lower species richness, and reduced alpha diversity. A combined untargeted and semi-targeted LC-MS/MS metabolomics approach identified a distinct SI metabolic footprint, with bile acids and amino acids being the most abundant classes of metabolites. Host and host/microbe-derived bile acids were particularly abundant in SI samples. The application of a fast culturomics approach to two SI samples enabled species-level characterization, resulting in the identification of 90 bacterial species, including five potential novel species. The present study demonstrates the efficacy of our novel sampling MD in enabling comprehensive SI microbiome analysis through an integrative multi-omics approach, allowing the identification of distinct microbiome signatures between SI and fecal samples.

Dietary peptides are increasingly linked to inflammatory gastrointestinal diseases, exemplified by coeliac disease. Coeliac disease is caused by an acquired immune response to proline- and glutamine-rich gluten peptides, which bottleneck proteolysis and provide substrates for immune recognition. Enzyme therapies aim to eliminate gluten immunogenic peptides as an adjunct to gluten-free diet.

To investigate overlooked aspects of enzyme development given difficulties in translating preclinical efficacy into clinical benefit.

We assessed mode-of-action, target organ and drug delivery in the context of digestive physiology and motility for gluten-digesting enzymes on the market or in development until 1 December 2024.

Most enzymes were gastric endopeptidases specific for proline or glutamine residues. Gastric enzymes may achieve poor enzyme-substrate exposure due to limited mixing and rapid emptying of water-soluble particles. Moreover, endopeptidases cleave proteins/peptides into shorter peptides but do not systematically cleave protein into absorbable fractions. Natural digestive physiology provides thorough mixing at the intestinal brush border, which produces exopeptidases necessary to fully digest proline-rich peptides. Despite reduced activity in patients with coeliac disease, exopeptidases remain underexplored as therapeutic agents. Given limited substrate scope and end-to-end digestion, exopeptidases are ineffective as single agents, requiring functional combinations. Furthermore, vulnerability to gastric acid requires stabilisation or formulation for rapid enteric release.

Enzymes should be stabilised throughout the gastrointestinal tract including the small intestine. Exopeptidases perform a critical function by systematically generating absorbable fractions, warranting future investigation as therapeutic agents. Sensitive and translational biomarkers are needed to better assess enzyme efficacy in real-meal conditions.

Ulcerative colitis (UC) is a chronic autoimmune disease and seriously affects the normal life of patients. Conventional therapeutic drugs are difficult to meet clinical needs. Traditional Chinese medicine (TCM) ingredients could effectively alleviate the symptoms of UC by anti-inflammatory, anti-oxidative, regulating the gut microbiota, and repairing the colonic epithelial barrier, but their low solubility and bioavailability severely limit their clinical application. Nano-drug delivery systems (NDDS) combined with TCM ingredients is a promising option for treating UC, and they could significantly enhance the stability, solubility, and bioavailability of TCM ingredients. The review describes the anti-UC mechanisms of TCM ingredients, systematically summarizes various kinds of NDDS for TCM ingredients according to different routes of administration, and highlights the advantages of NDDS for TCM ingredients in the treatmentof UC. In addition, we discuss the limitations of existing NDDS for TCM ingredients and the development direction in the future. This review will provide a basis for the future development of anti-UC NDDS for TCM ingredients.

Secondary hyperoxaluria is an acquired oxalate metabolic disorder characterized by increased urinary oxalate excretion. Reducing exogenous oxalate absorption through enzyme therapy represents a promising therapeutic strategy. However, the extremely acidic pH and protease-rich environment of the upper gastrointestinal tract pose major obstacles for the oral administration of protein therapeutics. OxDc-A0, a novel gastro-tolerant recombinant oxalate decarboxylase, can degrade oxalate in the stomach, thereby limiting the oxalate pool in the gastrointestinal tract and reducing oxalate absorption and urinary excretion. This study aimed to investigate the pharmacodynamics, pharmacokinetics, and safety profile of OxDc-A0 to assess its drug likeliness. The pharmacodynamics were evaluated in vitro and in hyperoxaluria beagle dog model induced by a high-oxalate diet. OxDc-A0 exhibited excellent gastric tolerance and significant efficacy in reducing urinary oxalate excretion in the dog model with hyperoxaluria. The safety of OxDc-A0 was evaluated in Sprague-Dawley rats, beagle dogs, and golden hamsters according to the guidelines for preclinical safety studies. No adverse effects were observed on the central nervous, cardiovascular, or respiratory system in rats or dogs treated orally with OxDc-A0 up to 37,500 U/kg. Pharmacokinetic studies showed that OxDc-A0 is non-systemically absorbed and is mainly distributed in the gastrointestinal tract. Toxicological studies showed that OxDc-A0 has excellent tolerance, with a NOAEL of 37,500 U/kg/day in both rats and dogs. The maximum tolerated dose was ≥ 105,000 U/kg in rats and ≥ 87,000 U/kg in dogs. Overall, OxDc-A0 shows great potential as a new drug candidate for treating secondary hyperoxaluria.

Helicobacter pylori is known for colonizing the gastric mucosa and instigating severe upper gastrointestinal diseases such as gastritis, gastroduodenal ulcers, and gastric cancer. To date, there is no data available on the oral cavity as transmission site, whether H. pylori can survive in the oral cavity or in human saliva. The aim of the study was to investigate the influence of oral microorganisms and human saliva on the survival of H. pylori in human saliva.

H. pylori strains KE, a motile derivate of type strain H. pylori 26695, and H. pylori SS1, a clinical isolate from a gastric biopsy, were grown in human pooled saliva (pooled from 4 healthy human donors, 0.22 μm filter-sterilized) or in BBF (Brucella browth formula; control) either as mono-cultures or in co-culture with Streptococcus mutans, Streptococcus oralis, Actinomyces naeslundii, Lacticaseibacillus casei and Candida dubliniensis. Bacterial survival of H. pylori and the oral microorganisms were investigated using colony forming units (CFU) assay and MALDI-TOF MS at baseline and after 24, 48 and 168 h.

In saliva, H. pylori KE demonstrated enhanced survival in co-culture with S. mutans, A. naeslundii, and C. dubliniensis, enduring for at least 48 h. In contrast, L. casei and S. oralis inhibited H. pylori KE in saliva. H. pylori KE could not be cultured after 168 h in saliva, neither in mono- nor co-culture. In contrast, H. pylori SS1 in saliva could be cultured after 168 h in co-culture with S. mutans and C. dubliniensis, but not in mono-culture. In BBF, H. pylori KE could be cultured after 168 h with S. mutans, L. casei and C. dubliniensis, and H. pylori SS1 with L. casei and C. dubliniensis, but not with S. mutans. Notably, the co-cultured microorganisms survived at high CFU numbers similar to those of the monocultures.

The study suggests that H. pylori can transiently survive in human saliva and even with presence of certain oral microorganisms. However, it may not be a permanent resident of the oral microbiota. The co-survival with oral microorganisms emphasizes the necessity for studying the role of the oral microbiota in the infectious and transmission cycle of H. pylori.

The oral route of drug administration is often preferred by patients and healthcare providers due to its convenience, ease of use, non-invasiveness, and patient acceptance. However, traditional oral dosage forms have several limitations, including low bioavailability, limited drug loading capacity, and stability and storage issues, particularly with solutions and suspensions. Over the years, researchers have dedicated considerable effort to developing novel oral drug delivery systems to overcome these limitations. This review discusses various challenges associated with oral drug delivery systems, including biological, pharmaceutical, and physicochemical barriers. It also explores common delivery approaches, such as gastroretentive drug delivery, small intestine drug delivery, and colon-targeting drug delivery systems. Additionally, numerous strategies aimed at improving oral drug delivery efficiency are reviewed, including solid dispersion, absorption enhancers, lipidbased formulations, nanoparticles, polymer-based nanocarriers, liposomal formulations, microencapsulation, and micellar formulations. Furthermore, innovative approaches like orally disintegrating tablets (ODT), orally disintegrating films (ODF), layered tablets, micro particulates, self-nano emulsifying formulations (SNEF), and controlled release dosage forms are explored for their potential in enhancing oral drug delivery efficiency and promoting patients' compliance. Overall, this review highlights significant progress in addressing challenges in the pharmaceutical industry and clinical settings, offering novel approaches for the development of effective oral drug delivery systems.

Microbiomes provide key contributions to health and potentially important therapeutic targets. Conceived nearly 30 years ago, the prebiotic concept posits that targeted modulation of host microbial communities through the provision of selectively utilized growth substrates provides an effective approach to improving health. Although the basic tenets of this concept remain the same, it is timely to address certain challenges pertaining to prebiotics, including establishing that prebiotic-induced microbiota modulation causes the health outcome, determining which members within a complex microbial community directly utilize specific substrates in vivo and when those microbial effects sufficiently satisfy selectivity requirements, and clarification of the scientific principles on which the term 'prebiotic' is predicated to inspire proper use. In this Expert Recommendation, we provide a framework for the classification of compounds as prebiotics. We discuss ecological principles by which substrates modulate microbiomes and methodologies useful for characterizing such changes. We then propose statistical approaches that can be used to establish causal links between selective effects on the microbiome and health effects on the host, which can help address existing challenges. We use this information to provide the minimum criteria needed to classify compounds as prebiotics. Furthermore, communications to consumers and regulatory approaches to prebiotics worldwide are discussed.

Hydroxypropyl methyl cellulose acetate succinate (HPMCAS) is one of the polymers of choice in formulating amorphous solid dispersions (ASDs) and helps to sustain high levels of drug supersaturation by delaying drug crystallization. Herein, the impact of HPMCAS chemistry on the solution crystallization kinetics of a fast-crystallizing lipophilic drug, posaconazole (PCZ), from the aqueous bulk phase and the drug-rich phase generated by liquid-liquid phase separation (LLPS), was studied. Three grades of HPMCAS: L, M, and H, which differ in the degree of acetyl and succinoyl substitution (A/S ratio), were compared. The influence of the polymers on the nucleation induction time, and LLPS concentration of PCZ, as well as the size, ζ-potential and composition of the nano-sized drug-rich phase was determined. An increase in the nucleation induction time was observed with an increase in the polymer A/S ratio. A blue shift in the fluorescence emission spectrum of PCZ suggested a greater extent of interaction between PCZ and HPMCAS with an increase in the A/S ratio. More polymer partitioning into the drug-rich phase was also observed with an increase in the A/S ratio, resulting in smaller droplets. A greater extent of ionization of HPMCAS upon increasing the pH from 5.5 to 7.5 decreased the hydrophobicity of the polymer resulting in shorter nucleation induction times. The phase behavior of PCZ in ASD release studies was consistent with these observations, where the shortest duration of supersaturation was observed with the L grade. Although the H grade provided the best inhibition of crystallization, complete release was only observed at higher pH. HPMCAS grade thus influences the kinetics of PCZ crystallization following release from an ASD, as well as the extent of release at physiologically relevant pH conditions. This study provides insights into the role of HPMCAS chemistry and ionization as factors influencing its ability to act as a crystallization inhibitor.

Hypertension is very common and a major risk factor for cardiovascular disease, heart failure, chronic kidney disease, strokes, and death. However, at present only 14% of patients of developing countries have their blood pressure (BP) well controlled. The causes for the failure to control the BP are multiple and one of them could be the formulation of antihypertensive drugs.

The recent development of nanotechnology by incorporating the drugs into nanoparticles is a new promising field of nanomedicine and preliminary studies have shown this nanoformulation to be more effective in the treatment of hypertension than the existing drug formulations. Another recent development is the nanoformulation of genes used for the treatment of hypertension and cardiovascular diseases. For current information, a Medline search was conducted between 2017 and 2024 and 36 pertinent papers were selected.

The nanoformulations of drugs help achieve better drug concentrations, improve drug stability, low solubility, short half life, oral bioavailability, narrow therapeutic index, and poor pharmacokinetic and pharmacodynamic profiles, and decrease the adverse effects of antihypertensive drugs. Also, the nanoformulation of genes for the treatment of hypertension has been shown in preliminary studies to be effective, but more research is needed.

An emerging concern globally, particularly in developed countries, is the rising prevalence of Inflammatory Bowel Disease (IBD), such as Crohn's disease. Oral delivery technologies that can release the active therapeutic cargo specifically at selected sites of inflammation offer great promise to maximise treatment outcomes and minimise off-target effects. Therapeutic strategies for IBD have expanded in recent years, with an increasing focus on biologic and nucleic acid-based therapies. Reliable site-specific delivery in the gastrointestinal (GI) tract is particularly crucial for these therapeutics to ensure sufficient concentrations in the targeted cells. Ingestible smart capsules hold great potential for precise drug delivery. Despite previous unsuccessful endeavours to commercialise drug delivery smart capsules, the current rise in demand and recent advancements in component development, manufacturing, and miniaturisation have reignited interest in ingestible devices. Consequently, this review analyses the advancements in various mechanical and electrical components associated with ingestible smart drug delivery capsules. These components include modules for device localisation, actuation and retention within the GI tract, signal transmission, drug release, power supply, and payload storage. Challenges and constraints associated with previous capsule design functionality are presented, followed by a critical outlook on future design considerations to ensure efficient and reliable site-specific delivery for the local treatment of GI disorders.

Bioactive peptides hold significant potential for enhancing human health, however, their limited oral bioavailability poses a substantial barrier to their widespread use in the food and pharmaceutical industries. This article reviews the key factors influencing the absorption efficiency of oral bioactive peptides, including issues related to bitter taste perception, challenges in gastrointestinal environmental stability, and limitations in transmembrane transport. Furthermore, it highlights the latest technologies, such as osmotic technology, chemical modification, and advanced delivery systems, and discusses their advantages in enhancing the stability of bioactive peptides and facilitating intestinal absorption. In addition, the application and challenges of common delivery systems such as liposomes, emulsions, polymer nanoparticles, and hydrogels in oral bioactive peptide delivery are also discussed. This paper aims to provide a theoretical foundation for scientific research and practical applications of oral delivery of bioactive peptides, thereby promoting the further development of bioactive peptides in the context of human health.

Establishing an in vitro - in vivo correlation (IVIVC) for oral modified release (MR) formulations would make it possible to substitute an in vitro dissolution test for human bioequivalence (BE) studies when changing the formulation or manufacturing methods. However, the number of IVIVC applications and approvals are reportedly low. One of the main reasons for failure to obtain IVIVCs using conventional methodologies may be the lack of consideration of the dissolution and absorption mechanisms of drugs in the physiological environment. In particular, it is difficult to obtain IVIVC using conventional methodologies for drugs with non-linear absorption processes. Therefore, the aim of the present study was to develop a physiologically based biopharmaceutics model (PBBM) that enables Level A IVIVCs for mirabegron MR formulations with non-linear absorption characteristics. Using human pharmacokinetic (PK) data for immediate-release formulations of mirabegron, the luminal drug concentration-dependent membrane permeation coefficient was calculated through curve fitting. The membrane permeation coefficient data were then applied to the human PK data of the MR formulations to estimate the in vivo dissolution rate by curve fitting. It was assumed that in vivo dissolution could be described using a zero-order rate equation. Furthermore, a Levy plot was generated using the estimated in vivo dissolution rate and the in vitro dissolution rate obtained from the literature. Finally, the dissolution rate of the MR formulations from the Levy plot was applied to the PBBM to predict the oral PK of the mirabegron MR formulations. This PB-IVIVC approach successfully generated linear Levy plots with slopes of almost 1.0 for MR formulations with different dose strengths and dissolution rates. The Cmax values of the MR formulations were accurately predicted using this approach, whereas the prediction errors for AUC exceeded the Level A IVIVC criteria. This can be attributed to the incomplete description of colonic absorption in the current PBBM.

Whey protein emulsion gel is an ideal model food for revealing how the multilength scale food structures affect food digestion, as their structure and mechanical properties can be precisely manipulated by controlling the type and intensity of intermolecular interactions between protein molecules. However, there are still significant understanding gaps among intermolecular interactions, protein aggregation and gelation, emulsion gel formation, gel breakdown in the gastrointestinal tract (GIT), and the practical use of whey protein emulsion gels, which limits their GIT-targeted applications. In this regard, the relationship between the structure and digestion behavior of heat-set whey protein emulsion gels is reviewed and discussed mainly from the following aspects: (1) structural characteristics of whey protein molecules; (2) how different types of intermolecular interactions influence heat-induced aggregation and gelation of whey protein in the aqueous solutions and the oil-in-water emulsions, and the mechanical properties of the final gels; (3) functions of the mouth, the stomach, and the small intestine in processing of solid foods, and how different types of intermolecular interactions influence the breakdown properties of heat-set whey protein emulsion gels in GIT (i.e., their respective role in controlling gel digestion). Finally, the implications of knowledge derived from the formation and gastrointestinal breakdown of heat-set whey protein emulsion gels for developing controlled delivery vehicles, human satiety enhancers, and sensory modifiers are highlighted.

Historically, the intestinal lymphatics were considered passive conduits for fluids, immune cells, dietary lipids, lipid soluble vitamins, and lipophilic drugs. Studies of intestinal lymphatic drug delivery in the late 20th century focused primarily on the drugs' physicochemical properties, especially high lipophilicity, that resulted in intestinal lymphatic transport. More recent discoveries have changed our traditional view by demonstrating that the lymphatics are active, plastic, and tissue-specific players in a range of biological and pathological processes, including within the intestine. These findings have, in turn, inspired exploration of lymph-specific therapies for a range of diseases, as well as the development of more sophisticated strategies to actively deliver drugs or vaccines to the intestinal lymph, including a range of nanotechnologies, lipid prodrugs, and lipid-conjugated materials that "hitchhike" onto lymphatic transport pathways. With the increasing development of novel therapeutics such as biologics, there has been interest in whether these therapeutics are absorbed and transported through intestinal lymph after oral administration. Here we review the current state of understanding of the anatomy and physiology of the gastrointestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. We summarize the current state-of-the-art approaches to deliver drugs and quantify their uptake into the intestinal lymphatic system. Finally, and excitingly, we discuss recent examples of significant pharmacokinetic and therapeutic benefits achieved via intestinal lymphatic drug delivery. We also propose approaches to advance the development and clinical application of intestinal lymphatic delivery strategies in the future. SIGNIFICANCE STATEMENT: This comprehensive review details the understanding of the anatomy and physiology of the intestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. It highlights current state-of-the-art approaches to deliver drugs to the intestinal lymphatics and the shift toward the use of these strategies to achieve pharmacokinetic and therapeutic benefits for patients.

Inflammatory bowel disease (IBD) manifests as inflammation in the colon, rectum, and ileum, presenting a global health concern with increasing prevalence. Therefore, effective anti-inflammatory therapy stands as a promising strategy for the prevention and management of IBD. However, conventional nano drug delivery systems (NDDSs) for IBD face many challenges in targeting the intestine, such as physiological and pathological barriers, genetic variants, disease severity, and nutritional status, which often result in nonspecific tissue distribution and uncontrolled drug release. To address these limitations, stimulus-responsive NDDSs have received considerable attention in recent years due to their advantages in providing controlled release and enhanced targeting. This review provides an overview of the pathophysiological mechanisms underlying IBD and summarizes recent advancements in microenvironmental stimulus-responsive nanocarriers for IBD therapy. These carriers utilize physicochemical stimuli such as pH, reactive oxygen species, enzymes, and redox substances to deliver drugs for IBD treatment. Additionally, pivotal challenges in the future development and clinical translation of stimulus-responsive NDDSs are emphasized. By offering insights into the development and optimization of stimulus-responsive drug delivery nanoplatforms, this review aims to facilitate their application in treating IBD. STATEMENT OF SIGNIFICANCE: This review highlights recent advancements in stimulus-responsive nano drug delivery systems (NDDSs) for the treatment of inflammatory bowel disease (IBD). These innovative nanoplatforms respond to specific environmental triggers, such as pH reactive oxygen species, enzymes, and redox substances, to release drugs directly at the inflammation site. By summarizing the latest research, our work underscores the potential of these technologies to improve drug targeting and efficacy, offering new directions for IBD therapy. This review is significant as it provides a comprehensive overview for researchers and clinicians, facilitating the development of more effective treatments for IBD and other chronic inflammatory diseases.

The intestinal luminal pH profile varies from stomach to rectum and becomes disrupted in diseases. However, little is known about the pH dependence of incretin hormone secretion, with most in vitro studies having failed to consider this modulatory factor or having used nonphysiological buffer systems. Here, we report the extracellular pH (pHe) dependence of glucagon-like peptide-1 (GLP-1) exocytosis from L cells.

The pHe dependence of GLP-1 release from GLUTag cells and murine ex vivo primary gut cultures was detected by ELISA. GLP-1 release was measured over a range of pHe under a physiological (CO2/HCO3 -) buffering regime and in its absence (HEPES buffer). The relationship between intracellular pH (pHi) and pHe was mapped given that at least some component of pH sensitivity is likely to be intracellular.

GLP-1 secretion from L cells was pHe-dependent and stimulated under alkaline conditions. In the absence of glucose or extracellular calcium, secretion remained at a pHe-insensitive baseline. pHi followed changes in pHe, but the relationship was offset to more alkaline levels in the absence of CO2/HCO3 - buffer and became shallower if [Cl-] changes that normally accompany [HCO3 -] changes were compensated iso-osmotically with gluconate.

GLP-1 secretion is sensitive to pHe and the buffer present. Exploiting this mechanism therapeutically may benefit patients with obesity.

Human cryptosporidiosis is distributed worldwide, and it is recognised as a leading cause of acute diarrhoea and death in infants in low- and middle-income countries. Besides immune status, the higher incidence and severity of this gastrointestinal disease in young children could also be attributed to the digestive environment. For instance, human gastrointestinal physiology undergoes significant changes with age, however the role this variability plays in Cryptosporidium parvum pathogenesis is not known. In this study, we analysed for the first time the impact of digestive physicochemical parameters on C. parvum infection in a human and age-dependent context using a dynamic in vitro gastrointestinal model.

Our results showed that the parasite excystation, releasing sporozoites from oocysts, occurs in the duodenum compartment after one hour of digestion in both child (from 6 months to 2 years) and adult experimental conditions. In the child small intestine, slightly less sporozoites were released from excystation compared to adult, however they exhibited a higher luciferase activity, suggesting a better physiological state. Sporozoites collected from the child jejunum compartment also showed a higher ability to invade human intestinal epithelial cells compared to the adult condition. Global analysis of the parasite transcriptome through RNA-sequencing demonstrated a more pronounced modulation in ileal effluents compared to gastric ones, albeit showing less susceptibility to age-related digestive condition. Further analysis of gene expression and enriched pathways showed that oocysts are highly active in protein synthesis in the stomach compartment, whereas sporozoites released in the ileum showed downregulation of glycolysis as well as strong modulation of genes potentially related to gliding motility and secreted effectors.

Digestion in a sophisticated in vitro gastrointestinal model revealed that invasive sporozoite stages are released in the small intestine, and are highly abundant and active in the ileum compartment, supporting reported C. parvum tissue tropism. Our comparative analysis suggests that physicochemical parameters encountered in the child digestive environment can influence the amount, physiological state and possibly invasiveness of sporozoites released in the small intestine, thus potentially contributing to the higher susceptibility of young individuals to cryptosporidiosis.

The oral route stands out as the most commonly used method for drug administration, prized for its non-invasive nature, patient compliance, and easy administration. Several elements influence the absorption of oral medications, including their solubility, permeability across mucosal membranes, and stability within the gastrointestinal (GI) environment. Research has delved into comprehending physicochemical, biochemical, metabolic, and biological obstacles that impact the bioavailability of a drug. To improve oral drug absorption, several pharmaceutical technologies and delivery methods have been studied, including cyclodextrins, micelles, nanocarriers, and lipid-based carriers. This review examines both traditional and innovative drug delivery methods, as well as the physiological and pharmacological barriers influencing medication bioavailability when taken orally. Additionally, it describes the challenges and advancements in developing formulations suitable for oral use.

A variety of enabling formulations has been developed to address poor oral drug absorption caused by insufficient dissolution in the gastrointestinal tract. As the in vivo performance of these formulations is a result of a complex interplay between dissolution, digestion and permeation, development of suitable in vitro assays that captures these phenomena are called for. The enabling-absorption (ENA) device, consisting of a donor and receiver chamber separated by a semipermeable membrane, has successfully been used to study the performance of lipid-based formulations. In this work, the ENA device was prepared with two different setups (a Caco-2 cell monolayer and an artificial lipid membrane) to study the performance of a lipid-based formulation (LBF), an amorphous solid dispersion (ASD) and the potential benefit of combining the two formulation strategies. An in vivo pharmacokinetic study in rats was performed to evaluate the in vitro-in vivo correlation. In the ENA, high drug concentrations in the donor chamber did not translate to a high mass transfer, which was particularly evident for the ASD as compared to the LBF. The solubility of the polymer used in the ASD was strongly affected by pH-shifts in vitro, and the ph_dependence resulted in poor in vivo performance of the formulation. The dissolution was however increased in vitro when the ASD was combined with a blank lipid-based formulation. This beneficial effect was also observed in vivo, where the drug exposure of the ASD increased significantly when the ASD was co-administered with the blank LBF. To conclude, the in vitro model managed to capture solubility limitations and strategies to overcome these for one of the formulations studied. The correlation between the in vivo exposure of the drug exposure and AUC in the ENA was good for the non pH-sensitive formulations. The deconvoluted pharmacokinetic data indicated that the receiver chamber was a better predictor for the in vivo performance of the drug, however both chambers provided valuable insights to the observed outcome in vivo. This shows that the advanced in vitro setting used herein successfully could explain absorption differences of highly complex formulations.

To treat colonic diseases more effectively, improved therapies are urgently needed. In this respect, delivering drugs locally to the colon is a key strategy to achieve higher local drug concentrations while minimizing systemic side effects. Understanding the luminal environment is crucial to efficiently develop such targeted therapies and to predict drug disposition in the colon. In this clinical study, we collected colonic contents from an undisturbed fasted proximal colon via colonoscopy and characterized their composition with regard to drug disposition. Colonic pH, osmolality, protein content, bile salts, lipids, phospholipids and short-chain fatty acids were investigated in 10 healthy volunteers (8 male and 2 female, age 19-25). The unique environment of the proximal colon was reflected in the composition of the sampled luminal fluids and the effect of the microbiota could be observed on the pH (median 6.55), the composition of bile salts (majority deconjugated and secondary), and the abundance of short-chain fatty acids. At the same time, an increase in phospholipid concentration, osmolality and total protein content compared to reported ileal values was seen, likely resulting from desiccation. Lipids could only be found in low quantities and mainly in the form of cholesterol and free fatty acids, showing almost complete digestion and absorption by the time luminal contents reach the colon. All characteristics also displayed the considerable intersubject variability found in different regions of the gastrointestinal tract. This study contributes to an improved understanding of the luminal conditions in the proximal colon and facilitates the development of new predictive tools to study colonic drug absorption.

The small intestinal crypts harbor secretory Paneth cells (PCs) which express bactericidal peptides that are crucial for maintaining intestinal homeostasis. Considering the diverse environmental conditions throughout the course of the small intestine, multiple subtypes of PCs are expected to exist. We applied single-cell RNA-sequencing of PCs combined with deep bulk RNA-sequencing on PC populations of different small intestinal locations and discovered several expression-based PC clusters. Some of these are discrete and resemble tuft cell-like PCs, goblet cell (GC)-like PCs, PCs expressing stem cell markers, and atypical PCs. Other clusters are less discrete but appear to be derived from different locations along the intestinal tract and have environment-dictated functions such as food digestion and antimicrobial peptide production. A comprehensive spatial analysis using Resolve Bioscience was conducted, leading to the identification of different PC's transcriptomic identities along the different compartments of the intestine, but not between PCs in the crypts themselves.

Fiber-based technologies are widely used in various industries, but their use in pharmaceuticals remains limited. While melt extrusion is a standard method for producing medical fibers such as sutures, it is rarely used for pharmaceutical fiber-based dosage forms. The EsoCap system is a notable exception, using a melt-extruded water-soluble filament as the drug release trigger mechanism. The challenge of producing drug-loaded fibers, particularly due to the use of spinning oils, and the processing of the fibers are addressed in this work using other approaches. The aim of this study was to develop processes for the production and processing of pharmaceutical fibers for targeted drug delivery. Fibers loaded with polyvinyl alcohol and fluorescein sodium as a model drug were successfully prepared by a continuous melt extrusion process and directly spun. These fibers exhibited uniform surface smoothness and consistent tensile strength. In addition, the fibers were further processed into tubular dosage forms using a modified knitting machine and demonstrated rapid drug release in a flow cell.

In vivo studies of formulation performance with in vitro and/or in silico simulations are often limited by significant gaps in our knowledge of the interaction between administered dosage forms and the human gastrointestinal tract. This work presents a novel approach for the investigation of gastric motility influence on dosage form performance, by combining biopredictive dissolution tests in an innovative PhysioCell apparatus with mechanistic physiology-based pharmacokinetic modeling. The methodology was based on the pharmacokinetic data from a large (n = 118) cohort of healthy volunteers who ingested a capsule containing a highly soluble and rapidly absorbed drug under fasted conditions. The developed dissolution tests included biorelevant media, varied fluid flows, and mechanical stress events of physiological timing and intensity. The dissolution results were used as inputs for pharmacokinetic modeling that led to the deduction of five patterns of gastric motility and their prevalence in the studied population. As these patterns significantly influenced the observed pharmacokinetic profiles, the proposed methodology is potentially useful to other in vitro-in vivo predictions involving immediate-release oral dosage forms.

Food can change various physiological parameters along the gastrointestinal tract, potentially impacting postprandial drug absorption. It is thus important to consider different in vivo conditions during in vitro studies. Therefore, a novel dissolution medium simulating variable postprandial pH values and lipid concentrations was developed and used in this study. Additionally, by establishing and validating a suitable analytical method, the effects of these parameters on the dissolution of a model drug, cinnarizine, and on its distribution between the lipid and aqueous phases of the medium were studied. Both parameters, pH value and lipid concentration, were shown to influence cinnarizine behavior in the in vitro dissolution studies. The amount of dissolved drug decreased with increasing pH due to cinnarizine's decreasing solubility. At pH values 5 and 7, the higher concentration of lipids in the medium increased drug dissolution, and most of the dissolved drug was distributed in the lipid phase. In all media with a lower pH of 3, dissolution was fast and complete, with a significant amount of drug distributed in the lipid phase. These results are in accordance with the in vivo observed positive food effect on cinnarizine bioavailability described in the literature. The developed medium, with its ability to easily adjust the pH level and lipid concentration, thus offers a promising tool for assessing the effect of co-ingested food on the dissolution kinetics of poorly soluble drugs.

In order to improve the drug-likeness qualities, the antimalarial endochin-like quinolone (ELQ) scaffold has been modified by replacing the 4-(trifluoromethoxy)phenyl portion with an isoidide unit that is further adjustable by varying the distal O-substituents. As expected, the water solubilities of the new analogs are greatly improved, and the melting points are lower. However, the antimalarial potency of the new analogs is reduced to EC50 > 1 millimolar, a result ascribable to the hydrophilic nature of the new substitution.

The presence of Vibrio parahaemolyticus (Vp) in different production stages of seafood has generated negative impacts on both public health and the sustainability of the industry. To further better investigate the fitness of Vp at the phenotypical level, a great number of studies have been conducted in recent years using plate counting methods. In the meantime, with the increasing accessibility of the next generation sequencing and the advances in analytical chemistry techniques, omics-oriented biotechnologies have further advanced our knowledge in the survival and virulence mechanisms of Vp at various molecular levels. These observations provide insights to guide the development of novel prevention and control strategies and benefit the monitoring and mitigation of food safety risks associated with Vp contamination. To timely capture these recent advances, this review firstly summarizes the most recent phenotypical level studies and provide insights about the survival of Vp under important in vitro stresses and on aquatic products. After that, molecular survival mechanisms of Vp at transcriptomic and proteomic levels are summarized and discussed. Looking forward, other newer omics-biotechnology such as metabolomics and secretomics show great potential to be used for confirming the cellular responses of Vp. Powerful data mining tools from the field of machine learning and artificial intelligence, that can better utilize the omics data and solve complex problems in the processing, analysis, and interpretation of omics data, will further improve our mechanistic understanding of Vp.

Oral solid dosage forms are most frequently administered with a glass of water which empties from the stomach relatively fast, but with a certain variability in its emptying kinetics. The purpose of this study was thus to simulate different individual water gastric emptying (GE) patterns in an in vitro glass-bead flow-through dissolution system. Further, the effect of GE on the dissolution of model drugs from immediate-release tablets was assessed by determining the amount of dissolved drug in the samples pumped out of the stomach compartment. Additionally, different HCl solutions were used as dissolution media to assess the effect of the variability of pH of the gastric fluid on the dissolution of three model drugs: paracetamol, diclofenac sodium, and dipyridamole. The difference in fast and slow GE kinetics resulted in different dissolution profiles of paracetamol in all studied media. For diclofenac sodium and dipyridamole tablets, the effect of GE kinetics was well observed only in media, where the solubility was not a limiting factor. Therefore, GE kinetics of co-ingested water influences the drug release from immediate-release tablets, however, in certain cases, other parameters influencing drug dissolution can partly or fully hinder the expression of this effect.

Age-related neurodegenerative diseases involving amyloid aggregation remain one of the biggest challenges of modern medicine. Alterations in the gastrointestinal microbiome play an active role in the aetiology of neurological disorders. Here, we dissect the amyloidogenic properties of biofilm-associated proteins (BAPs) of the gut microbiota and their implications for synucleinopathies. We demonstrate that BAPs are naturally assembled as amyloid-like fibrils in insoluble fractions isolated from the human gut microbiota. We show that BAP genes are part of the accessory genomes, revealing microbiome variability. Remarkably, the abundance of certain BAP genes in the gut microbiome is correlated with Parkinson's disease (PD) incidence. Using cultured dopaminergic neurons and Caenorhabditis elegans models, we report that BAP-derived amyloids induce α-synuclein aggregation. Our results show that the chaperone-mediated autophagy is compromised by BAP amyloids. Indeed, inoculation of BAP fibrils into the brains of wild-type mice promote key pathological features of PD. Therefore, our findings establish the use of BAP amyloids as potential targets and biomarkers of α-synucleinopathies.

Variability of the gastrointestinal tract is rarely reflected in in vitro test protocols but often turns out to be crucial for the oral dosage form performance. In this study, we present a generation method of dissolution profiles accounting for the variability of fasted gastric conditions. The workflow featured 20 biopredictive tests within the physiological variability. The experimental array was constructed with the use of the design of experiments, based on three parameters: gastric pH and timings of the intragastric stress event and gastric emptying. Then, the resulting dissolution profiles served as a training data set for the dissolution process modeling with the machine learning algorithms. This allowed us to generate individual dissolution profiles under a customizable gastric pH and motility patterns. For the first time ever, we used the method to successfully elucidate dissolution properties of two dosage forms: pellet-filled capsules and bare pellets of the marketed dabigatran etexilate product Pradaxa. We showed that the dissolution of capsules was triggered by mechanical stresses and thus was characterized by higher variability and a longer dissolution onset than observed for pellets. Hence, we proved the applicability of the method for the in vitro and in silico characterization of immediate-release dosage forms and, potentially, for the improvement of in vitro-in vivo extrapolation.

Curcumin (CUR) is a natural polyphenol that holds promise for treating ulcerative colitis (UC), yet oral administration of CUR exhibits limited bioavailability and existing formulations for oral delivery of CUR often suffer from unsatisfactory loading capacity. This study presents hydroxyethyl starch-curcumin microspheres (HC-MSs) with excellent CUR loading capacity (54.52 %), and the HC-MSs can further encapsulate anti-inflammatory drugs dexamethasone (DEX) to obtain a combination formulation (DHC-MSs) with high DEX loading capacity (19.91 %), for combination therapy of UC. The microspheres were successfully engineered, retaining the anti-oxidative and anti-inflammatory activities of parental CUR and demonstrating excellent biocompatibility and controlled release properties, notably triggered by α-amylase, facilitating targeted drug delivery to inflamed sites. In a mouse UC model induced by dextran sulfate sodium, the microspheres effectively accumulated in inflamed colons and both HC-MSs and DHC-MSs exhibited superior therapeutic efficacy in alleviating UC symptoms compared to free DEX. Moreover, mechanistic exploration uncovered the multifaceted therapeutic mechanisms of these formulations, encompassing anti-inflammatory actions, mitigation of spleen enlargement, and modulation of gut microbiota composition. These findings underscore the potential of HC-MSs and DHC-MSs as promising formulations for UC, with implications for advancing treatment modalities for various inflammatory bowel disorders.

The kinetics, thermodynamics, and degradation of malvidin mono- and diglucosides were studied following a holistic approach by extending to the basic medium. In acidic conditions, the reversible kinetics of the flavylium cation toward the equilibrium is controlled by the hydration and cis-trans isomerization steps, while in the basic medium, the OH- nucleophilic addition to the anionic quinoidal bases is the slowest step. There is a pH range (transition pHs), between the acidic and basic paradigms, that includes physiological pH (7.4), where degradation reactions occur faster, preventing the system from reaching the equilibrium. The transition pH of the diglucoside is narrower, and in contrast with the monoglucoside, there is no evidence for the formation of colored oligomers among the degradation products. Noteworthy, OH- addition in position 4 to form B42-, a kinetic product that decreases the overall equilibration rate, was observed only for the diglucoside.

Consumption of fructo- (FOS) and galacto-oligosaccharides (GOS) has health benefits which have been linked in part to short-chain fatty acids (SCFA) production by the gut microbiota. However, detailed knowledge of this process in the human intestine is lacking. We aimed to determine the acute fermentation kinetics of a FOS:GOS mixture in healthy males using a naso-intestinal catheter for sampling directly in the ileum or colon. We studied the fate of SCFA as substrates for glucose and lipid metabolism by the host after infusion of 13C-SCFA. In the human distal ileum, no fermentation of FOS:GOS, nor SCFA production, or bacterial cross-feeding was observed. The relative composition of intestinal microbiota changed rapidly during the test day, which demonstrates the relevance of postprandial intestinal sampling to track acute responses of the microbial community toward interventions. SCFA were vividly taken up and metabolized by the host as shown by incorporation of 13C in various host metabolites.

Clostridioides difficile is an anaerobic gastrointestinal pathogen that spreads through the environment as dormant spores. To survive, replicate, and sporulate in the host intestine, C. difficile must adapt to a variety of conditions in its environment, including changes in pH, the availability of metabolites, host immune factors, and a diverse array of other species. Prior studies showed that changes in intestinal conditions, such as pH, can affect C. difficile toxin production, spore formation, and cell survival. However, little is understood about the specific genes and pathways that facilitate environmental adaptation and lead to changes in C. difficile cell outcomes. In this study, we investigated two genes, CD2505 and CD2506, that are differentially regulated by pH to determine if they impact C. difficile growth and sporulation. Using deletion mutants, we examined the effects of both genes (herein smrR and smrT) on sporulation frequency, toxin production, and antimicrobial resistance. We determined that SmrR is a repressor of smrRT that responds to pH and suppresses sporulation and toxin production through regulation of the SmrT transporter. Further, we showed that SmrT confers resistance to erythromycin and lincomycin, establishing a connection between the regulation of sporulation and antimicrobial resistance.IMPORTANCEClostridioides difficile is a mammalian pathogen that colonizes the large intestine and produces toxins that lead to severe diarrheal disease. C. difficile is a major threat to public health due to its intrinsic resistance to antimicrobials and its ability to form dormant spores that are easily spread from host to host. In this study, we examined the contribution of two genes, smrR and smrT, on sporulation, toxin production, and antimicrobial resistance. Our results indicate that SmrR represses smrT expression, while production of SmrT increases spore and toxin production, as well as resistance to antibiotics.

The emergence of antibiotic-resistant strains, the decreased effectiveness of conventional therapies, and the side effects have led researchers to seek a safer, more cost-effective, patient-friendly, and effective method that does not develop antibiotic resistance. With progress in synthetic biology and genetic engineering, genetically engineered microorganisms effective in treatment, prophylaxis, drug delivery, and diagnosis have been developed. The present study reviews the types of genetically engineered bacteria and phages, their impacts on diseases, cancer, and metabolic and inflammatory disorders, the biosynthesis of these modified strains, the route of administration, and their effects on the environment. We conclude that genetically engineered microorganisms can be considered promising candidates for adjunctive treatment of diseases and cancers.