Bottom-Up Fabrication of Multilayer Enteric Devices for the Oral Delivery of Peptides

Inkjet Printing of Pharmaceuticals

Inkjet printing (IJP) is an additive manufacturing process that selectively deposits ink materials, layer-by-layer, to create 3D objects or 2D patterns with precise control over their structure and composition. This technology has emerged as an attractive and versatile approach to address the ever-evolving demands of personalized medicine in the healthcare industry. Although originally developed for nonhealthcare applications, IJP harnesses the potential of pharma-inks, which are meticulously formulated inks containing drugs and pharmaceutical excipients. Delving into the formulation and components of pharma-inks, the key to precise and adaptable material deposition enabled by IJP is unraveled. The review extends its focus to substrate materials, including paper, films, foams, lenses, and 3D-printed materials, showcasing their diverse advantages, while exploring a wide spectrum of therapeutic applications. Additionally, the potential benefits of hardware and software improvements, along with artificial intelligence integration, are discussed to enhance IJP's precision and efficiency. Embracing these advancements, IJP holds immense potential to reshape traditional medicine manufacturing processes, ushering in an era of medical precision. However, further exploration and optimization are needed to fully utilize IJP's healthcare capabilities. As researchers push the boundaries of IJP, the vision of patient-specific treatment is on the horizon of becoming a tangible reality.

The Role of Soft Robotic Micromachines in the Future of Medical Devices and Personalized Medicine

Developments in medical device design result in advances in wearable technologies, minimally invasive surgical techniques, and patient-specific approaches to medicine. In this review, we analyze the trajectory of biomedical and engineering approaches to soft robotics for healthcare applications. We review current literature across spatial scales and biocompatibility, focusing on engineering done at the biotic-abiotic interface. From traditional techniques for robot design to advances in tunable material chemistry, we look broadly at the field for opportunities to advance healthcare solutions in the future. We present an extracellular matrix-based robotic actuator and propose how biomaterials and proteins may influence the future of medical device design.

One-step preparation of Cr2O3-based inks with long-term dispersion stability for inkjet applications

Inkjet printing of functional materials has shown a wide range of applications in advertising, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition techniques. Nevertheless, the sedimentation risk of the refractory functional materials dispensed in inks hinders their further implementation. Herein, we present a bottom-up ink preparation strategy based on Cr₂O₃ by a one-step solvothermal method. The obtained ink remained stable under an equivalent natural sediment test for 2.5 years. The chemical composition of the solvothermal product was characterized, and the mechanism of the superior dispersion stability of Cr₂O₃ particles was analysed. These amorphous Cr₂O₃ particles were capped by ligands generated via low-temperature solvothermal reactions. Ethanol and acetylacetone covering the particle surfaces play an essential role in enhancing the solubility of Cr₂O₃ particles in the solvent forming the ultrastable colloidal ink. Moreover, this ink was successfully printed using a direct-write inkjet system JetLab®II on nylon fabrics, and the printed area of the fabrics shows a spectral correlation coefficient of 0.9043 to green leaves. Finally, we believe that the one-step bottom-up fabrication method of Cr₂O₃-based pigment inks may provide a general approach for preparing metal oxide-based pigment inks with long-term dispersion stability.

Future Perspectives of Oral Delivery of Next Generation Therapies for Treatment of Skin Diseases

Gene therapies have conspicuously bloomed in recent years as evidenced by the increasing number of cell-, gene-, and oligo-based approved therapies. These therapies hold great promise for dermatological disorders with high unmet need, for example, epidermolysis bullosa or pachyonychia congenita. Furthermore, the recent clinical success of clustered regularly interspaced short palindromic repeats (CRISPR) for genome editing in humans will undoubtedly contribute to defining a new wave of therapies. Like biologics, naked nucleic acids are denatured inside the gastrointestinal tract and need to be administered via injections. For a treatment to be effective, a sufficient amount of a given regimen needs to reach systemic circulation. Multiple companies are racing to develop novel oral drug delivery approaches to circumvent the proteolytic and acidic milieu of the gastrointestinal tract. In this review, we provide an overview of the evolution of the gene therapy landscape, with a deep focus on gene and oligonucleotide therapies in clinical trials aimed at treating skin diseases. We then examine the progress made in drug delivery, with particular attention on the peptide field and drug-device combinations that deliver macromolecules into the gastrointestinal tract. Such novel devices could potentially be applied to administer other therapeutics including genes and CRISPR-based systems.

Devices for drug delivery in the gastrointestinal tract: A review of systems physically interacting with the mucosa for enhanced delivery

The delivery of macromolecules via the gastrointestinal (GI) tract remains a significant challenge. A variety of technologies using physical modes of drug delivery have been developed and investigated to overcome the epithelial cell layer of the GI tract for local and systemic delivery. These technologies include direct injection, jetting, ultrasound, and iontophoresis, which have been largely adapted from transdermal drug delivery. Direct injection of agents using needles through endoscopy has been used clinically for over a century. Jetting, a needle-less method of drug delivery where a high-speed stream of fluid medication penetrates tissue, has been evaluated pre-clinically for delivery of agents into the buccal mucosa. Ultrasound has been shown to be beneficial in enhancing delivery of macromolecules, including nucleic acids, in pre-clinical animal models. The application of an electric field gradient to drive drugs into tissues through the technique of iontophoresis has been shown to deliver highly toxic chemotherapies into GI tissues. Here in, we provide an in-depth overview of these physical modes of drug delivery in the GI tract and their clinical and preclinical uses.

Hot punching for loading of biodegradable microcontainers with budesonide-Soluplus film

Micro-reservoir based drug delivery systems have the potential to provide targeted drug release locally in the intestine, i.e. at the inflamed areas of the intestine of patients with inflammatory bowel disease (IBD). In this study, microcontainers with a diameter of 300 µm and a height of 100 µm, asymmetrical geometry and the possibility to provide unidirectional release, are fabricated in the biodegradable polymer poly-ɛ-caprolactone (PCL) using hot punching. As a first step towards local treatment of IBD, a novel method for loading of microcontainers with the corticosteroid budesonide is developed. For this purpose, a budesonide-Soluplus drug-polymer film is prepared by spin coating and loaded into the microcontainer reservoirs using hot punching. The processing parameters are optimized to achieve a complete loading of a large number of containers in a single step. A poly(lactic-co-glycolic acid) (PLGA) 50:50 lid is subsequently applied by spray coating. Solid-state characterization indicates that the drug is in an amorphous state in the drug-polymer films and the in vitro drug release profile showed a 68% release over 10 h. The results demonstrate that hot punching can be employed both as a production and loading method for PCL microcontainers with the perspective of local treatment of IBD.

Impact of nanosizing on the formation and characteristics of polymethacrylate films: micro- versus nano-suspensions

Aqueous-based film coating suspensions are associated with reliance on alkalinising reagents and poor film formation. The impact of particle size in this process and resultant film properties remains unclear. This study offers the first direct comparison of film formation properties between aqueous micro- and nano-suspensions of the enteric polymer Eudragit S100. High-pressure homogenisation was employed to produce nano-suspensions of the enteric polymer. Formed enteric suspensions (micro- and nano-) were evaluated in terms of size, morphology, and ability to form film; with resultant films analysed in terms of; film thickness, mechanical and thermoplastic properties, water uptake, weight loss, and drug permeability in acidic medium. High-pressure homogenisation yielded particles within a submicron range (150-200 nm). Produced nano-suspensions formed significantly thinner films (p < 0.01), at lower plasticiser concentrations, than films cast from micro-suspensions (differences in thickness up to 100 µm); however, exhibited comparative gastro-resistant properties (p > 0.05) in terms of water uptake (∼25% w/w), weight loss (<16% w/w) and drug permeability (<0.1%). Interestingly, nano-suspension-based films exhibited lower glass transition temperatures (Tg) (p < 0.01), when compared to films cast from micro-suspensions (∼7-20 °C difference), indicating enhanced plasticisation. This was reflected in film mechanical properties; where nano-suspension-based films demonstrated significantly lower tensile strength (p < 0.01) and higher percentage elongation (p < 0.05), suggesting high elasticity. Thinner, highly elastic films were formed from nano-suspensions, compared to films cast from micro-suspensions, exhibiting comparative properties; obviating the need for alkalinising agents and high concentrations of plasticiser.

Ethyl cellulose coated sustained release aspirin spherules for treating COVID-19: DOE led rapid optimization using arbitrary interface; applicable for emergency situations

This work attempts to resolve one of the key issues related to the design and development of sustained-release spherule of aspirin for oral formulations, tailored to treat COVID-19. For that, in the Design of Experiments (DOE) an arbitrary interface, "coating efficiency" (CE) is introduced and scaled the cumulative percentage coating (CPC) to get predictable control over drug release (DR). Subsequently, the granules containing ASP are converted to spherules and then to Ethyl cellulose (EC) Coated spherules (CS) by a novel bed coating during the rolling (BCDR) process. Among spherules, one with 0.35 mm than 0.71 mm shows required properties. The CS has a low 120⁰ angle by Optical Microscopy (OM), smooth surface without cracks by scanning electron microscopy (SEM), and better flow properties (Angle of repose 29.69 ± 0.78⁰, Carr's index 6.73 ± 2.24%, Hausner's Ratio 1.07 ± 0.03) than granules and spherules. Once certain structure-dependent control over release is attained (EC coated spherules shows 10% reduction in burst release (BR) than uncoated spherules showing a release of 80-91%) the predictability is achieved and Design of space (DOS) by DOE (CE-70.14%and CPC-200% and DR-61.54%) is established. The results of DOE to experimentally validated results were within 20% deviation. The aspirin is changing its crystal structure by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) from Form-I to Form-II showing polymorphism inside the drug reservoir with respect to the process. This CE and CPC approach in DOE can be used for delivery system design of other labile drugs similar to aspirin in emergency situations.

Impact of Microdevice Geometry on Transit and Retention in the Murine Gastrointestinal Tract

Oral protein delivery technologies often depend on encapsulating or enclosing the protein cargo to protect it against pH-driven degradation in the stomach or enzymatic digestion in the small intestine. An emergent methodology is to encapsulate therapeutics in microscale, asymmetric, planar microparticles, referred to as microdevices. Previous work has shown that, compared to spherical particles, planar microdevices have longer residence times in the GI tract, but it remains unclear how specific design choices (e.g., material selection, particle diameter) impact microdevice behavior in vivo. Recent advances in microdevice fabrication through picoliter printing have expanded the range of device sizes that can be fabricated in a rapid manner. However, relatively little work has explored how device size governs their behavior in the intestinal environment. In this study, we probe the impact of geometry of planar microdevices on their transit and accumulation in the murine GI tract. Additionally, we present a strategy to label, image, and quantify these distributions in intact tissue in a continuous manner, enabling a more detailed understanding of device distribution and transit kinetics than previously possible. We show that smaller particles (194.6 ± 7 μm.diameter) tend to empty from the stomach faster than midsize (293.2 ± 7 μm.diameter) and larger devices (440.9 ± 9 μm.diameter) and that larger devices distribute more broadly in the GI tract and exit slower than other geometries. In general, we observed an inverse correlation between device diameter and GI transit rate. These results inform the future design of drug delivery systems, using particle geometry as an engineering design parameter to control device accumulation and distribution in the GI tract. Additionally, our image analysis process provides greater insight into the tissue level distribution and transit of particle populations. Using this technique, we demonstrate that microdevices act and translocate independently, as opposed to transiting in one homogeneous mass, meaning that target sites will likely be exposed to devices multiple times over the course of hours post administration. This imaging technique and associated findings enable data-informed design of future particle delivery systems, allowing orthogonal control of transit and distribution kinetics in vivo independent of material and cargo selection.

X-ray Imaging for Gastrointestinal Tracking of Microscale Oral Drug Delivery Devices

Microscale devices are promising tools to overcome specific challenges within oral drug delivery. Despite the availability of advanced high-quality imaging techniques, visualization and tracking of microscale devices in the gastrointestinal (GI) tract is still a challenge. This work explores the possibilities of applying planar X-ray imaging and computed tomography (CT) scanning for visualization and tracking of microscale devices in the GI tract of rats. Microcontainers (MCs) are an example of microscale devices that have shown great potential as an oral drug delivery system. Barium sulfate (BaSO₄) loaded into the cavity of the MCs increases their overall X-ray contrast, which allows them to be easily tracked. The BaSO₄-loaded MCs are quantitatively tracked throughout the entire GI tract of rats by planar X-ray imaging and visualized in 3D by CT scanning. The majority of the BaSO₄-loaded MCs are observed to retain in the stomach for 0.5-2 h, enter the cecum after 3-4 h, and leave the cecum and colon 8-10 h post-administration. The imaging approaches can be adopted and used with other types of microscale devices when investigating GI behavior in, for example, preclinical trials and potential clinical studies.

Consumer-Grade Inkjet Printer for Versatile and Precise Chemical Deposition

Two simple, mechanical modifications are introduced to a consumer-grade inkjet printer to greatly increase its applicability. First, roller isolation bars are added to unlock multiple prints on the same substrate without smearing. This enables printing on a diverse set of substrates (rigid, elastic, liquid, granular, and sticky). Second, spring loadings are added to increase the print precision up to 50-fold, which facilitates alignment to a pre-patterned substrate or between successive prints. Utilizing the expanded substrate compatibility and the increased print precision, we explore tunable loading of drug combinations into microdevices. This loading method has promising applications within point-of-care personalized medication. Furthermore, we show how inkjet printers with array-type printheads (in our case, 6 x 90 nozzles) allow for quasi-simultaneous loading of reactants into microfluidic systems. The ability to do a quasi-simultaneous introduction of chemicals may be particularly useful for studies of rapidly reacting systems of three or more reactants, where premature introduction can shift the initial conditions from the intended. We believe that our modifications to an affordable system will inspire researchers to explore the possibilities of inkjet printing even further.

Inkjet printing of small molecules, biologics, and nanoparticles

During the last decades, inkjet printing has emerged as a novel technology and attracted the attention of the pharmaceutical industry, as a potential method for manufacturing personalized and customizable dosage forms to deliver drugs. Commonly, the desired drug is dissolved or dispersed within the ink and then dispensed in various dosage forms. Using this approach, several studies have been conducted to load hydrophilic or poorly water-soluble small molecules onto the surface of different solid substrates, including films, tablets, microneedles, and smart data-enriched edible pharmaceuticals, using two-dimensional and three-dimensional inkjet printing methods, with high dose accuracy and reproducibility. Furthermore, biological drugs, such as peptides, proteins, growth factors, and plasmids, have also been evaluated with positive results, eliciting the expected biological response; nonetheless, minor changes in the structure of these compounds with significant impaired activity cannot be dismissed. Another strategy using inkjet printing is to disperse drug-loaded nanoscale particles in the ink liquid, such as nanosuspension, nanocomplexes, or nanoparticles, which have been explored with promising results. Although these favorable outcomes, the proper selection of ink constituents and the inkjet printer, the correlation of printing cycles and effectively printed doses, the stability studies of drugs within the ink and the optimal analysis of samples before and after the printing process are the main challenges for inkjet printing, and therefore, this review analyzes these aspects to assess the body of current literature and help to guide future investigations on this field.

2D and 3D inkjet printing of biopharmaceuticals - A review of trends and future perspectives in research and manufacturing

There is an ongoing global shift in pharmaceutical business models from small molecule drugs to biologics. This increase in complexity is in response to advancements in our diagnoses and understanding of diseases. With the more targeted approach coupled with its inherently more costly development and manufacturing, 2D and 3D printing are being explored as suitable techniques to deliver more personalised and affordable routes to drug discovery and manufacturing. In this review, we explore first the business context underlying this shift to biopharmaceuticals and provide an update on the latest work exploring discovery and pharmaceutics. We then draw on multiple disciplines to help reveal the shared challenges facing researchers and firms aiming to develop biopharmaceuticals, specifically when using the most commonly explored manufacturing routes of drop-on-demand inkjet printing and pneumatic extrusion. This includes separating out how to consider mechanical and chemical influences during manufacturing, the role of the chosen hardware and the challenges of aqueous formulation based on similar challenges being faced by the printing industry. Together, this provides a review of existing work and guidance for researchers and industry to help with the de-risking and rapid development of future biopharmaceutical products.

Systemic delivery of peptides by the oral route: Formulation and medicinal chemistry approaches

In its 33 years, ADDR has published regularly on the po5tential of oral delivery of biologics especially peptides and proteins. In the intervening period, analysis of the preclinical and clinical trial failures of many purported platform technologies has led to reflection on the true status of the field and reigning in of expectations. Oral formulations of semaglutide, octreotide, and salmon calcitonin have completed Phase III trials, with oral semaglutide being approved by the FDA in 2019. The progress made with oral peptide formulations based on traditional permeation enhancers is against a background of low and variable oral bioavailability values of ~1%, leading to a current perception that only potent peptides with a viable cost of synthesis can be realistically considered. Desirable features of candidates should include a large therapeutic index, some stability in the GI tract, a long elimination half-life, and a relatively low clearance rate. Administration in nanoparticle formats have largely disappointed, with few prototypes reaching clinical trials: insufficient particle loading, lack of controlled release, low epithelial particle uptake, and lack of scalable synthesis being the main reasons for discontinuation. Disruptive technologies based on engineered devices promise improvements, but scale-up and toxicology aspects are issues to address. In parallel, medicinal chemists are synthesizing stable hydrophobic macrocyclic candidate peptides of lower molecular weight and with potential for greater oral bioavailability than linear peptides, but perhaps without the same requirement for elaborate drug delivery systems. In summary, while there have been advances in understanding the limitations of peptides for oral delivery, low membrane permeability, metabolism, and high clearance rates continue to hamper progress.

Orally ingestible medical devices for gut engineering

Orally ingestible medical devices provide significant advancement for diagnosis and treatment of gastrointestinal (GI) tract-related conditions. From micro- to macroscale devices, with designs ranging from very simple to complex, these medical devices can be used for site-directed drug delivery in the GI tract, real-time imaging and sensing of gut biomarkers. Equipped with uni-direction release, or self-propulsion, or origami design, these microdevices are breaking the barriers associated with drug delivery, including biologics, across the GI tract. Further, on-board microelectronics allow imaging and sensing of gut tissue and biomarkers, providing a more comprehensive understanding of underlying pathophysiological conditions. We provide an overview of recent advances in orally ingestible medical devices towards drug delivery, imaging and sensing. Challenges associated with gut microenvironment, together with various activation/actuation modalities of medical devices for micromanipulation of the gut are discussed. We have critically examined the relationship between materials–device design–pharmacological responses with respect to existing regulatory guidelines and provided a clear roadmap for the future.

Cubic Microcontainers Improve In Situ Colonic Mucoadhesion and Absorption of Amoxicillin in Rats

An increased interest in colonic drug delivery has led to a higher focus on the design of delivery devices targeting this part of the gastrointestinal tract. Microcontainers have previously facilitated an increase in oral bioavailability of drugs. The surface texture and shape of microcontainers have proven to influence the mucoadhesion ex vivo. In the present work, these findings were further investigated using an in situ closed-loop perfusion technique in the rat colon, which allowed for simultaneous evaluation of mucoadhesion of the microcontainers as well as drug absorption. Cylindrical, triangular and cubic microcontainers, with the same exterior surface area, were evaluated based on in vitro release, in situ mucoadhesion and in situ absorption of amoxicillin. Additionally, the mucoadhesion of empty cylindrical microcontainers with and without pillars on the top surface was investigated. From the microscopy analysis of the colon sections after the in situ study, it was evident that a significantly higher percentage of cubic microcontainers than cylindrical microcontainers adhered to the intestinal mucus. Furthermore, the absorption rate constants and blood samples indicated that amoxicillin in cubic microcontainers was absorbed more readily than when cylindrical or triangular microcontainers were dosed. This could be due to a higher degree of mucoadhesion for these particular microcontainers.

Micro and nanoscale technologies in oral drug delivery

Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro- and nanoscale technologies, with an unprecedented ability to create, control, and measure micro- or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.