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[Display omitted] • CULTEX® RFS-Vilnius technology enables delivery of small doses of drug powder aerosols to cellular models. • Different rank order of permeability identified for compounds tested in solution or dry powder form. • Pulmonary cell models of upper and lower airway allow to pinpoint differences in permeability across the airway tree. • TGF-β1 induced epithelial disruption is a good model to measure the impact of diseased pulmonary barriers in paracellular drug transport. Inhaled therapy confers key advantages for the treatment of topical pulmonary diseases and offers potential for systemic delivery of medicines. Dry powder inhalers (DPIs) are generally the preferred devices for pulmonary delivery due to improved stability and satisfactory patient compliance. However, the mechanisms governing drug powder dissolution and availability in the lung and poorly understood. Here, we report a new in vitro system to study epithelial absorption of inhaled dry powders in lung barrier models of the upper and lower airway. The system is based on a CULTEX® RFS (Radial Flow System) cell exposure module joined to a Vilnius aerosol generator and allows the coupling of drug dissolution and permeability assessments. The cellular models recapitulate the barrier morphology and function of healthy and diseased pulmonary epithelium and incorporate the mucosal barrier to enable the investigation of drug powder dissolution in biorelevant conditions. With this system, we found differences in permeability across the airway tree and pinpointed the impact of diseased barriers in paracellular drug transport. Furthermore, we identified a different rank order of permeability for compounds tested in solution or powder form. These results highlight the value of this in vitro drug aerosolization setup for use in research and development of inhaled medicines. [ABSTRACT FROM AUTHOR]

Cocrystal engineering is a potent strategy for enhancing drug properties, but its application in spray-drying has been limited. Furthermore, concurrently introducing two drugs and realizing simultaneous pharmacological effects at the target site is challenging. This is particularly evident for oral formulations designed for systemic use, but the local administration of drugs at the target site displays the potential to overcome this problem. Herein, we investigated the potential of cocrystallization principles for use in developing dry powder inhaler formulations of anti-tuberculosis drugs. We focused on the formation of cocrystals of 4-aminosalicylic acid (PAS) and isoniazid (INH), which are crucial components of tuberculosis treatment. Via spray-drying, we successfully produced spray-dried particles of PAS-INH that exhibited hydrogen bonding interactions between the molecules. Aerosolization performance evaluation with an Andersen Cascade Impactor (ACI) confirmed the concurrent deposition of both drugs, highlighting the potential of our particle design for use in the co-delivery of PAS-INH. Furthermore, simulated lung dissolution studies using the ACI and Transwell inserts revealed synchronized dissolution patterns, indicating promising prospects for use in effective drug delivery. This innovative approach to tuberculosis therapy has significant implications for improving treatment efficacy and enhancing patient adherence, potentially revolutionizing tuberculosis treatment. [Display omitted] • PAS-INH cocrystal powder was obtained by spray-drying. • Ternary phase diagram of PAS-INH cocrystal system in solvent was constructed. • Spray-dried cocrystal concurrently deposited on each stage of ACI. • Synchronized dissolution patterns were observed from spray-dried cocrystals. [ABSTRACT FROM AUTHOR]

The aim of this study was to further evaluate and optimize the Transwell® system for assessing the dissolution behavior of orally inhaled drug products (OIDPs), using fluticasone propionate as a model drug. Sample preparation involved the collection of a relevant inhalable dose fraction through an anatomical mouth/throat model, resulting in a more uniform presentation of drug particles during the subsequent dissolution test. The method differed from previously published procedures by (1) using a 0.4 µm polycarbonate (PC) membrane, (2) stirring the receptor compartment, and (3) placing the drug-containing side of the filter paper face downwards, towards the PC membrane. A model developed in silico, paired with the results of in vitro studies, suggested that a dissolution medium providing a solubility of about 5 µg/mL would be a good starting point for the method’s development, resulting in mean transfer times that were about 10 times longer than those of a solution. Furthermore, the model suggested that larger donor/receptor and sampling volumes (3, 3.3 and 2 mL, respectively) will significantly reduce the so-called “mass effect”. The outcomes of this study shed further light on the impact of experimental conditions on the complex interplay of dissolution and diffusion within a volume-limited system, under non-sink conditions.

The placenta maintains the balance between nutrition and growth control of the fetus through selective and regulated supply of macronutrients such as carbohydrates, proteins, lipids, and critical micronutrients. Perturbations in the balanced supply of nutrients as found in gestational diseases and altered fetal development have been associated with changes in amino acid transport proteins, such as the System L amino acid heterodimeric exchangers LAT1/SLC7A5 and LAT2/SLC7A8. Syncytiotrophoblasts (STB) form the crucial cell layer at the placental barrier coordinating the transfer of essential amino acids such as leucine from the maternal to the fetal circulation. The System L-mediated leucine transport across the placental barrier is a Na + -independent process against a counter-directed gradient, maintained by a tightly regulated interplay between accumulative transporters, exchangers, and facilitators.The two methods described here allow to standardize and characterize the uptake kinetics of leucine in conventionally cultured BeWo cells and the transfer of leucine across the placental cell barrier using a BeWo monolayer in the Transwell ® system., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

[Display omitted] • Saturable and size-dependent transport of antibodies observed in bronchial epithelial cell models. • Synthetic mucus recapitulates impaired antibody mucodiffusion observed in bronchial mucus. • Disease-like bronchial epithelial cell models induced by TGF-β1 are a promising tool to quantify paracellular antibody transport. • FcRn-independent transcytosis across bronchial epithelial cell models observed for antibody fragments. Inhaled antibody therapy for the treatment of respiratory diseases is a promising strategy to maximize pulmonary exposure and reduce side effects associated with parenteral administration. However, the development of inhaled antibodies is often challenging due to a poor understanding of key mechanisms governing antibody absorption and clearance in healthy and diseased pulmonary epithelium. Here, we utilize well established Human Bronchial Epithelial Cell (HBEC) models grown at air–liquid interface to study the absorption process of antibodies and antibody fragments. With these cellular models, we recapitulate the morphology and function of healthy and diseased pulmonary epithelium, and incorporate the mucosal barrier to enable the investigation of both cellular permeability as well as mucodiffusion. We studied the saturation of antibody transport across the HBEC barriers and estimated the impact of disease-like epithelial barriers on antibody paracellular transport. Additionally, we identified a potential role of neonatal Fc receptor (FcRn)-independent and target-mediated transcytosis in the transport of Fragment antigen-binding (Fab) and F(ab)2 antibody fragments. Lastly, our models were able to pinpoint an impaired antibody diffusion across mucus gels. These mechanistic cellular models are promising in vitro tools to inform Physiologically-based Pharmacokinetic (PBPK) computational models for dose prediction toward de-risking the development of inhaled biologics. [ABSTRACT FROM AUTHOR]

The knowledge about enteric viral infection has vastly increased over the last eight years due to the development of intestinal organoids and enteroids that suppose a step forward from conventional studies using cell lines. Intestinal organoids and enteroids are three-dimensional (3D) models that closely mimic intestinal cellular heterogeneity and organization. The barrier function within these models has been adapted to facilitate viral studies. In this review, several adaptations (such as organoid-derived two-dimensional (2D) monolayers) and original intestinal 3D models are discussed. The specific advantages and applications, as well as improvements of each model are analyzed and an insight into the possible path for the field is given.

Human induced pluripotent stem cells (hiPSC) offer a tractable system to model the blood-brain barrier (BBB). Here we detail the assembly of a triple co-culture hiPSC-BBB model, using hiPSC-derived brain microvascular endothelial cells (BMEC), astrocytes, and mural cells (MC). Transendothelial electrical resistance (TEER) and sodium fluorescein (NaFl) permeability can be used to test the barrier properties. The model has applications in studying BBB-related pathology and for drug screening., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

The aim of this study was to further evaluate and optimize the Transwell® system for assessing the dissolution behavior of orally inhaled drug products (OIDPs), using fluticasone propionate as a model drug. Sample preparation involved the collection of a relevant inhalable dose fraction through an anatomical mouth/throat model, resulting in a more uniform presentation of drug particles during the subsequent dissolution test. The method differed from previously published procedures by (1) using a 0.4 µm polycarbonate (PC) membrane, (2) stirring the receptor compartment, and (3) placing the drug-containing side of the filter paper face downwards, towards the PC membrane. A model developed in silico, paired with the results of in vitro studies, suggested that a dissolution medium providing a solubility of about 5 µg/mL would be a good starting point for the method's development, resulting in mean transfer times that were about 10 times longer than those of a solution. Furthermore, the model suggested that larger donor/receptor and sampling volumes (3, 3.3 and 2 mL, respectively) will significantly reduce the so-called "mass effect". The outcomes of this study shed further light on the impact of experimental conditions on the complex interplay of dissolution and diffusion within a volume-limited system, under non-sink conditions. [ABSTRACT FROM AUTHOR]

Historically, knowledge of human host–enteric pathogen interactions has been elucidated from studies using cancer cells, animal models, clinical data, and occasionally, controlled human infection models. Although much has been learned from these studies, an understanding of the complex interactions between human viruses and the human intestinal epithelium was initially limited by the lack of nontransformed culture systems, which recapitulate the relevant heterogenous cell types that comprise the intestinal villus epithelium. New investigations using multicellular, physiologically active, organotypic cultures produced from intestinal stem cells isolated from biopsies or surgical specimens provide an exciting new avenue for understanding human specific pathogens and revealing previously unknown host–microbe interactions that affect replication and outcomes of human infections. Here, we summarize recent biologic discoveries using human intestinal organoids and human enteric viral pathogens. [ABSTRACT FROM AUTHOR]

Hydroxytyrosol (HT) is a natural phenolic antioxidant which has neuroprotective effects in models of Parkinson's disease (PD). Due to issues such as rapid metabolism, HT is unlikely to reach the brain at therapeutic concentrations required for a clinical effect. We have previously developed micellar nanocarriers from Pluronic F68® (P68) and dequalinium (DQA) which have suitable characteristics for brain delivery of antioxidants and iron chelators. The aim of this study was to utilise the P68 + DQA nanocarriers for HT alone, or in combination with the iron chelator deferoxamine (DFO), and assess their physical characteristics and ability to pass the blood–brain barrier and protect against rotenone in a cellular hCMEC/D3-SH-SY5Y co-culture system. Both HT and HT + DFO formulations were less than 170 nm in size and demonstrated high encapsulation efficiencies (up to 97%). P68 + DQA nanoformulation enhanced the mean blood–brain barrier (BBB) passage of HT by 50% (p < 0.0001, n = 6). This resulted in increased protection against rotenone induced cytotoxicity and oxidative stress by up to 12% and 9%, respectively, compared to the corresponding free drug treatments (p < 0.01, n = 6). This study demonstrates for the first time the incorporation of HT and HT + DFO into P68 + DQA nanocarriers and successful delivery of these nanocarriers across a BBB model to protect against PD-related oxidative stress. These nanocarriers warrant further investigation to evaluate whether this enhanced neuroprotection is exhibited in in vivo PD models. [ABSTRACT FROM AUTHOR]

The knowledge about enteric viral infection has vastly increased over the last eight years due to the development of intestinal organoids and enteroids that suppose a step forward from conventional studies using cell lines. Intestinal organoids and enteroids are three-dimensional (3D) models that closely mimic intestinal cellular heterogeneity and organization. The barrier function within these models has been adapted to facilitate viral studies. In this review, several adaptations (such as organoid-derived two-dimensional (2D) monolayers) and original intestinal 3D models are discussed. The specific advantages and applications, as well as improvements of each model are analyzed and an insight into the possible path for the field is given. [ABSTRACT FROM AUTHOR]

An essential property associated with leptospiral virulence is the pathogen's ability to translocate across host cells, enabling Leptospira to evade the host immune response, disseminate, and establish infection. Cell monolayer translocation assay allows for the quantification of Leptospira strain's competence to cross cell barriers while measuring the integrity of the polarized eukaryotic cell monolayer during this process.