The present study introduces a novel formulation approach for utilizing Lyotropic Liquid Crystals (LLCs) as sustained oral delivery systems. For this purpose, a novel bottom-up fabrication process was developed, enabling the casting of LLC beads with precise control over their diameter. Predetermining the effective diffusional interfacial surface of the beads enables regulation of the release rate of solubilized drugs from the LLCs. To prevent bead coalescence throughout shelf life, the LLC beads are embedded in a heat-sensitive gelatin-chitosan coacervate. Additionally, the study focuses on LLC beads formulated as pH-responsive systems, designed to attenuate the Higuchian primary diffusional burst in a gastric environment while enhancing the release of the solubilized load at an elevated pH (6.4). To demonstrate the applicability of the pH-responsive systems, the LLC beads were loaded with a lipophilic low water solubility (< 5 µg/mL) model drug, Celecoxib (CLXB). Although the water solubility of CLXB is not pH dependent, the Higuchian release constant of CLXB increased from 9.31 at pH 1.5 to 15.03 at pH 6.4. The pH dependency of CLXB release was achieved by the co-solubilization of additional compounds in the LLC structure, creating a pH-dependent environment that influences both the LLC structure and the release of the co-solubilized compounds. The enhanced release of CLXB in an elevated pH environment enables gaining a zero-order (R2 > 0.99) sustained release profile extending beyond 10 h in a release medium simulating the gastrointestinal (GI) tract environment. Additionally, the study investigated the association between the release of co-solubilized compounds and the micellar structure using techniques such as small-angle X-ray diffraction, nuclear magnetic resonance, and electron paramagnetic resonance. The results revealed a co-dependent relationship between the release of lipophilic compounds and changes of the LLC's curvature at different pH levels, suggesting that a compensatory mechanism operates between these two processes. These insights, combined with the innovative bottom-up fabrication method for LLC beads, provide valuable tools for controlling the release of lipophilic compounds from LLCs and for enhancing their effectiveness as controlled oral delivery systems.

Establishing a robust and intimate mucosal interface that allows medical devices to remain within lumen-confined organs for extended periods has valuable applications, particularly for gastrointestinal theranostics. Here, we report the development of an electroadhesive hydrogel interface for robust and prolonged mucosal retention after electrical activation (e-GLUE). The e-GLUE device is composed of cationic polymers interpenetrated within a tough hydrogel matrix. An e-GLUE electrode design eliminated the need for invasive submucosal placement of ground electrodes for electrical stimulation during endoscopic delivery. With an electrical stimulation treatment of about 1 minute, the cationic polymers diffuse and interact with polyanionic proteins that have a relatively slow cellular turnover rate in the deep mucosal tissue. This mucosal adhesion mechanism increased the adhesion energy of hydrogels on the mucosa by up to 30-fold and enabled in vivo gastric retention of e-GLUE devices in a pig stomach for up to 30 days. The adhesion strength was modulated by polycationic chain length, electrical stimulation time, gel thickness, cross-linking density, voltage amplitude, polycation concentration, and perimeter-to-area ratio of the electrode assembly. In porcine studies, e-GLUE demonstrated rapid mucosal adhesion in the presence of luminal fluid and mucus exposure. In proof-of-concept studies, we demonstrated e-GLUE applications for mucosal hemostasis, sustained local delivery of therapeutics, and intimate biosensing in the gastrointestinal tract, which is an ongoing clinical challenge for commercially available alternatives, such as endoclips and mucoadhesive. The e-GLUE platform could enable theranostic applications across a range of digestive diseases, including recurrent gastrointestinal bleeding and inflammatory bowel disease.

Low-moisture foods (LMFs) have been linked to Salmonella transmission due to the remarkable resilience of Salmonella against desiccation, allowing its survival for extended periods. Being metabolically inactive, Salmonella in LMFs exhibit extraordinary resistance to inactivation treatments. This study proposes a novel strategy for mitigating Salmonella in LMF products through a temperature cycling (TC) approach. Alternating the temperature between 4 °C and 37 °C on a daily basis reduced the viability of S. Typhimurium air-dried on surfaces by >4 log after 6 days. TC also diminished Salmonella resistance to acidity and reduced its virulence. The mechanism was elucidated through an integrated analysis of transcriptomics and proteomics data. Specifically, transcriptomic data revealed elevated levels of protein synthesis alongside active energy metabolism. Proteomic analysis demonstrated that these protein activities were associated primarily with the heat shock protein response. Taken together, the principal mechanism by which TC exerts its inhibitory effect appears to be the repeated induction of heat shock protein synthesis within Salmonella, ultimately leading to energy depletion. Finally, the efficacy of TC was validated on representative LMF samples, including flour, protein powder, and mixed spices. The most notable effect was observed in the mixed spices, with a reduction of 2.7 ± 0.2 log after 6 days (P < 0.05). In conclusion, the TC approach demonstrated in this study provides valuable insights into the management of foodborne pathogens in LMFs.

More than half of the global population is unable to consume dairy products due to lactose intolerance (hypolactasia). Current enzyme replacement therapy methods are insufficiently effective as a therapeutic approach to treating lactose intolerance. The encapsulation of β-galactosidase in polyelectrolyte microcapsules by using the layer-by-layer method could be a possible solution to this problem. In this study, adsorption and co-precipitation methods were employed for encapsulating β-galactosidase in polyelectrolyte microcapsules composed of (polyallylamine /polystyrene sulphonate)₃. As a result, the co-precipitation method was chosen for β-galactosidase encapsulation. The adsorption method permits to encapsulate six times less enzyme compared with the co-precipitation method; the β-galactosidase encapsulated via the co-precipitation method released no more than 20% of the initially encapsulated enzyme in pH 2 or 1 M NaCl solutions. In contrast, when using the sorption method, about 100% of the initially encapsulated enzyme was released from the microcapsules under the conditions described above. The co-precipitation method effectively prevents the complete loss of enzyme activity after 2 h of incubation in a solution with pH 2 while also alleviating the adverse effects of ionic strength. Consequently, the encapsulated form of β-galactosidase shows promise as a potential therapeutic agent for enzyme replacement therapy in the treatment of hypolactasia.

Ingestible electronics have the capacity to transform our ability to effectively diagnose and potentially treat a broad set of conditions. Current applications could be significantly enhanced by addressing poor electrode-tissue contact, lack of navigation, short dwell time, and limited battery life. Here we report the development of an ingestible, battery-free, and tissue-adhering robotic interface (IngRI) for non-invasive and chronic electrostimulation of the gut, which addresses challenges associated with contact, navigation, retention, and powering (C-N-R-P) faced by existing ingestibles. We show that near-field inductive coupling operating near 13.56 MHz was sufficient to power and modulate the IngRI to deliver therapeutically relevant electrostimulation, which can be further enhanced by a bio-inspired, hydrogel-enabled adhesive interface. In swine models, we demonstrated the electrical interaction of IngRI with the gastric mucosa by recording conductive signaling from the subcutaneous space. We further observed changes in plasma ghrelin levels, the "hunger hormone," while IngRI was activated in vivo, demonstrating its clinical potential in regulating appetite and treating other endocrine conditions. The results of this study suggest that concepts inspired by soft and wireless skin-interfacing electronic devices can be applied to ingestible electronics with potential clinical applications for evaluating and treating gastrointestinal conditions.

Postoperative ileus (POI) is the leading cause of prolonged hospital stay after abdominal surgery and is characterized by a functional paralysis of the digestive tract, leading to symptoms such as constipation, vomiting, and functional obstruction. Current treatments are mainly supportive and inefficacious and yield acute side effects. Although electrical stimulation studies have demonstrated encouraging pacing and entraining of the intestinal slow waves, no devices exist today to enable targeted intestinal reanimation. Here, we developed an ingestible self-propelling device for intestinal reanimation (INSPIRE) capable of restoring peristalsis through luminal electrical stimulation. Optimizing mechanical, material, and electrical design parameters, we validated optimal deployment, intestinal electrical luminal contact, self-propelling capability, safety, and degradation of the device in ex vivo and in vivo swine models. We compared the INSPIRE's effect on motility in models of normal and depressed motility and chemically induced ileus. Intestinal contraction improved by 44% in anesthetized animals and up to 140% in chemically induced ileus cases. In addition, passage time decreased from, on average, 8.6 days in controls to 2.5 days with the INSPIRE device, demonstrating significant improvement in motility. Luminal electrical stimulation of the intestine via the INSPIRE efficaciously restored peristaltic activity. This noninvasive option offers a promising solution for the treatment of ileus and other motility disorders.

Human-induced pluripotent stem cell-derived small intestinal epithelial cell (hiPSC-SIEC) monolayers are useful in vitro models for evaluating the gut mucosal barrier; however, their reactivity to cytokines, which are closely related to the regulation of mucosal barrier function, remains unclear. Interleukin (IL)-22 is a cytokine that contributes to regulate the mucosal barrier in the intestinal epithelia. Using microarray and gene set enrichment analysis, we found that hiPSC-SIEC monolayers activate the immune response and enhance the mucosal barrier in response to IL-22. Moreover, hiPSC-SIEC monolayers induced the gene expression of antimicrobials, including the regenerating islet-derived protein 3 family. Furthermore, IL-22 stimulation upregulated Mucin 2 secretion and gene expression of an enzyme that modifies sugar chains, suggesting alteration of the state of the mucus layer of hiPSC-SIEC monolayers. To evaluate its physiological significance, we measured the protective activity against Salmonella enterica subsp. enterica infection in hiPSC-SIEC monolayers and found that prestimulation with IL-22 reduced the number of viable intracellular bacteria. Collectively, these results suggest that hiPSC-SIEC monolayers enhance the mucosal barrier and inhibit infection by pathogenic bacteria in response to IL-22, as previously reported. These results can contribute to the further application of hiPSC-SIECs in evaluating mucosal barriers.

Effective therapies for obesity require invasive surgical and endoscopic interventions or high patient adherence, making it challenging for patients with obesity to effectively manage their disease. Gastric mechanoreceptors sense distension of the stomach and perform volume-dependent vagal signaling to initiate the gastric phase and influence satiety. In this study, we developed a new luminal stimulation modality to specifically activate these gastric stretch receptors to elicit a vagal afferent response commensurate with mechanical distension. We designed the Vibrating Ingestible BioElectronic Stimulator (VIBES) pill, an ingestible device that performs luminal vibratory stimulation to activate mechanoreceptors and stroke mucosal receptors, which induces serotonin release and yields a hormonal metabolic response commensurate with a fed state. We evaluated VIBES across 108 meals in swine which consistently led to diminished food intake (~40%, P < 0.0001) and minimized the weight gain rate (P < 0.05) as compared to untreated controls. Application of mechanoreceptor biology could transform our capacity to help patients suffering from nutritional disorders.

Effective therapies for obesity either require invasive surgical or endoscopic interventions or high patient adherence, making it challenging for the nearly 42% of American adults who suffer from obesity to effectively manage their disease. Gastric mechanoreceptors sense distension of the stomach and perform volume-dependent vagal signaling to initiate the gastric phase and influence satiety. In this study, we developed a new luminal stimulation modality to specifically activate these gastric stretch receptors to elicit a vagal afferent response commensurate with mechanical distension. Here we developed the Vibrating Ingestible BioElectronic Stimulator (VIBES) pill - an ingestible device that performs luminal vibratory stimulation to activate mechanoreceptors and stroke mucosal receptors, which induces serotonin release as well as yields a hormonal metabolic response commensurate with a fed state. We evaluated VIBES across 108 meals in swine which consistently led to diminished food intake (~40%, p< 0.0001) and minimized the weight gain rate (p< 0.03) as compared to untreated controls. Application of mechanoreceptor biology could transform our capacity to help patients suffering from nutritional disorders.

The in vitro release of theophylline from an extended-release dosage form was studied under different hydrodynamic conditions in a United States Pharmacopoeial (USP) dissolution system II and a bespoke in vitro tubular model of the human colon, the Dynamic Colon Model (DCM). Five biorelevant motility patterns extracted from in vivo data were applied to the DCM, mimicking the human proximal colon under baseline conditions and following stimulation using polyethylene glycol or maltose; these represent the lower and upper bounds of motility normally expected in vivo. In the USPII, tablet dissolution was affected by changing hydrodynamic conditions at different agitation speeds of 25, 50 and 100 rpm. Applying different motility patterns in the DCM affected the dissolution profiles produced, with theophylline release at 24 h ranging from 56.74 ± 2.00% (baseline) to 96.74 ± 9.63% (maltose-stimulated). The concentration profiles of theophylline were markedly localized when measured at different segments of the DCM tube, highlighting the importance of a segmented lumen in intestine models and in generating spatial information to support simple temporal dissolution profiles. The results suggested that the shear stresses invoked by the unstimulated, healthy adult human colon may be lower than those in the USPII at 25 rpm and thus insufficient to achieve total release of a therapeutic compound from a hydroxyethyl cellulose matrix. When operated under stimulated conditions, drug release in the DCM was between that achieved at 25 and 50 rpm in the USPII.

Oral drug delivery of proteins is limited by the degradative environment of the gastrointestinal tract and poor absorption, requiring parenteral administration of these drugs. Luminal mucus represents the initial steric and dynamic barrier to absorption. To overcome this barrier, we report the development of the RoboCap, an orally ingestible, robotic drug delivery capsule that locally clears the mucus layer, enhances luminal mixing, and topically deposits the drug payload in the small intestine to enhance drug absorption. RoboCap's mucus-clearing and churning movements are facilitated by an internal motor and by surface features that interact with small intestinal plicae circulares, villi, and mucus. Vancomycin (1.4 kilodaltons of glycopeptide) and insulin (5.8 kilodaltons of peptide) delivery mediated by RoboCap resulted in enhanced bioavailability 20- to 40-fold greater in ex vivo and in vivo swine models when compared with standard oral delivery (P < 0.05). Further, insulin delivery via the RoboCap resulted in therapeutic hypoglycemia, supporting its potential to facilitate oral delivery of drugs that are normally precluded by absorption limitations.

Oral delivery is preferred over other routes of drug administration by both patients and physicians. The bioavailability of some therapeutics that are delivered via the oral route is restricted due to the protease- and bacteria-rich environment in the gastrointestinal tract, and by the pH variability along the delivery route. Given these harsh environments, the oral delivery of therapeutic macromolecules is complicated and remains challenging. Various formulation approaches, including the use of permeation enhancers and nanosized carriers, as well as chemical alteration of the drug structure, have been studied as ways to improve the oral absorption of macromolecular drugs. Nevertheless, the bioavailability of marketed oral peptide medicines is often relatively poor. This review highlights the most recent and promising physical methods for improving the oral bioavailability of macromolecules such as peptides. These methods include microneedle injections, high-speed stream injectors, magnetic drug targeting, expandable hydrogels, and iontophoresis. We highlight the potential and challenges of these new technologies, which may impact the future approaches used by pharmaceutical companies to create more efficient and safer orally administered macromolecules. Teaser: Despite substantial effort, the oral delivery of macromolecules remains challenging due to their low bioavailability. This review discusses the potential, challenges, and safety concerns associated with new technologies and devices for oral macromolecule delivery.

Gastrointestinal-based drug delivery is considered the preferred mode of drug administration owing to its convenience for patients, which improves adherence. However, unique characteristics of the gastrointestinal tract (such as the digestive environment and constraints on transport across the gastrointestinal mucosa) limit the absorption of drugs. As a result, many medications, in particular biologics, still exist only or predominantly in injectable form. In this Review, we examine the fundamentals of gastrointestinal drug delivery to inform clinicians and pharmaceutical scientists. We discuss general principles, including the challenges that need to be overcome for successful drug formulation, and describe the unique features to consider for each gastrointestinal compartment when designing drug formulations for topical and systemic applications. We then discuss emerging technologies that seek to address remaining obstacles to successful gastrointestinal-based drug delivery.