Pulmonary Delivery of Biological Drugs

Effect of Acute Lung Injury (ALI) Induced by Lipopolysaccharide (LPS) on the Pulmonary Pharmacokinetics of an Antibody

OBJECTIVE

To investigate the effect of Lipopolysaccharide (LPS)-induced acute lung injury (ALI) on the pulmonary pharmacokinetics (PK) of a systemically administered antibody in mice.

METHOD

The PK of a non-target-binding antibody was evaluated in healthy mice and mice with intratracheal instillation of 5 mg/kg LPS. The plasma, bronchoalveolar lavage (BAL), trachea, bronchi, and lung homogenate PK of the antibody were measured following intravenous administration of 5 mg/kg antibody dose. Noncompartmental analysis was performed to determine AUC values. Antibody concentrations in all biological matrices were quantified using qualified ELISA. The effect of ALI on BAL albumin and total protein concentrations was also determined. BAL protein concentrations were corrected for dilution using plasma urea concentrations.

RESULTS

Intratracheal instillation of LPS and the resultant ALI led to ~2-4-fold higher concentrations of albumin and proteins in the BAL. LPS-induced ALI also notably altered the pulmonary PK of the antibody. The effect of ALI on the antibody PK was time and tissue dependent. The trachea and bronchi showed ~1.7-fold and ~1.4-fold lower antibody exposure compared with the control group, but the BAL fluid exhibited ~4-fold increase in antibody exposure following LPS treatment. Most noticeable changes in antibody PK occurred 24 h after LPS administration, and the effect was temporary for the bronchi and trachea. However, the changes in lung homogenate and, more notably, in BAL persisted until the end of the experiment. Thus, our investigation suggests that due to the acute nature of ALI-induced pathophysiology and the changing severity of the disease, the dose and timing of antibody administration following ALI may need to be optimized based on the target site of action (e.g., bronchi, trachea, BAL, lung parenchyma, etc.) to maximize the therapeutic effect of the antibody.

CONCLUSIONS

ALI may significantly affect pulmonary PK of systemically administered antibodies. Changes caused by ALI are time and tissue dependent, and hence, the timing and dose of antibody following ALI may need to be optimized to maximize the therapeutic effect of the antibody at the site of action.

Treatment of lung diseases via nanoparticles and nanorobots: Are these viable alternatives to overcome current treatments?

Challenges

Respiratory diseases remain challenging to treat, with current efforts primarily focused on managing symptoms rather than maintaining overall lung health. Traditional treatment methods, such as oral or parenteral administration of antiviral, antibacterial, and anti-inflammatory drugs, face limitations. These include difficulty in delivering therapeutic agents to pathogens residing deep in the airways and the risk of severe side effects due to high systemic drug concentrations. The growing threat of drug-resistant pathogens further complicates infection management.

Advancements

The lung's large surface area offers an attractive target for inhalation-based drug delivery. Nanoparticles (NP) enable uniform and sustained drug distribution across the alveolar network, overcoming challenges posed by complex lung anatomy. Recent breakthroughs in nanorobots (NR) have demonstrated precise navigation through biological environments, delivering therapies directly to affected lung areas with enhanced accuracy. Nanotechnology has also shown promise in treating lung cancer, with nanoparticles engineered to overcome biological barriers, improve drug solubility, and enable controlled drug release.

Future scope

This review explores the progress of NP and NR in addressing challenges in pulmonary drug delivery. These innovations allow targeted delivery of nucleic acids, drugs, or peptides to the pulmonary epithelium with unprecedented accuracy, offering significant potential for improving therapeutic effectiveness in respiratory disorders.

Dry powder formulations of hyperimmune serum

Effective strategies against the spread of respiratory viruses are needed, as tragically demonstrated during the COVID-19 pandemic. Apart from vaccines, other preventive or protective measures are necessary: one promising strategy involves the nasal delivery of preventive or protective agents, targeting the site of initial infection. Harnessing the immune system's ability to produce specific antibodies, a hyperimmune serum, collected from an individual vaccinated against SARS-CoV-2, was formulated as a dry powder for nasal administration. The selection of adequate excipients and process are key to maintaining protein stability and modulating the aerodynamic properties of the powders for reaching the desired respiratory regions. To this end, a hyperimmune serum was formulated with trehalose and mannitol as bulking agents during spray drying, then the ability of the redissolved immunoglobulins to bind Spike protein was verified by ELISA; foetal bovine serum was formulated in the same conditions as a reference. Moreover, a seroneutralization assay against SARS-CoV-2 pseudoviruses generated from different variants of concern was performed. The neutralizing ability of the serum was slightly reduced with respect to the starting serum when trehalose was used as a bulking agent. The powders were loaded in hypromellose capsules and aerosolized employing a nasal insufflator in an in vitro model of the nasal cavity connected to a Next Generation Impactor. The analysis of the powder distribution confirmed that all powders were inhalable and could target, at the same time, the upper and the lower airways. This is a preliminary proof-of-concept that this approach can constitute an effective strategy to provide broad coverage and protection against SARS-CoV-2, and in general against viruses affecting the airway. According to blood availability from donors, pools of hyperimmune sera could be rapidly formulated and administered, providing a simultaneous and timely neutralization of emerging viral variants.

Self-nanoemulsifying drug delivery system for nebulization: fabrication and evaluation for systemic delivery of atorvastatin

The study undertakes the development of an atorvastatin-loaded self-nanoemulsifying drug delivery system (SNEDDS) to improve its bioavailability. The SNEDDS were fabricated using oleic acid, Tween 80, and Span 80 by spontaneous emulsification. The SNEDDS were assessed for their particle size distribution, zeta potential, morphology, drug content, surface tension, viscosity, and drug release. The aerodynamic performance of the SNEDDS was evaluated using an Andersen cascade impactor, while the lipid-lowering potential of the SNEDDS was determined in Wistar rats using the analyzer "Microlab 300." The particle size of the SNEDDS ranged from 36 to 311 nm, with a polydispersity index (PDI) of 0.25-0.40. The zeta potential of the SNEDDS fluctuated from - 29.22 to - 38.26 mV, which declined to - 4.55 mV in the case of F5. The chitosan-coated formulation (F5) exhibited a higher viscosity (22.12 mPa s) and lower surface tension (0.056 dyne/cm) than other formulations (F1-F4). The non-coated formulation exhibited a significantly higher burst drug release, followed by a sustained drug release pattern (p ≤ 0.05) as compared to the coated formulation (F5). The nebulized SNEDDS achieved a dispersed fraction of 87 to 97%, where notably higher aerosol dispersion from F4 was attributed to its smaller particle size and circularity. The inhaled fraction of nebulized SNEDDS was 74-87%. The size of the SNEDDS droplets was the primary determinant affecting the aerodynamic performance of the SNEDDS during nebulization. The chitosan-coated SNEDDS achieved a higher antihyperlipidemic effect than marketed tablets, which shows the suitability of F5 for effective systemic delivery of atorvastatin through the lung.

Navigating the Development of Dry Powder for Inhalation: A CDMO Perspective

Interest in pulmonary/nasal routes for local delivery has significantly increased over the last decade owing to challenges faced in the delivery of molecules with poor solubility, systemic side effects, or new modalities such as biologics. This increasing interest has attracted new stakeholders to the field who have yet to explore inhaled drug product development. Contract development and manufacturing organizations (CDMOs) play a key role in supporting the development of drug products for inhalation, from early feasibility to post marketing. However, a critical gap exists for these newcomers: a clear, integrated, and a CDMO-centric roadmap for navigating the complexities of pulmonary/nasal drug product development. The purpose of this publication is to highlight the key aspects considered in the product development of inhaled dry powder products from a CDMO perspective, providing a novel and stepwise development strategy. A roadmap for the development of inhalable drug products is proposed with authors' recommendations to facilitate the decision-making process, starting from the definition of the desired target product profile followed by dose selection in preclinical studies. The importance of understanding the nature of the API, whether a small molecule or a biologic, will be highlighted. Additionally, technical guidance on the choice of formulation (dry powder/liquid) will be provided with special focus on dry powders. Selection criteria for the particle engineering technology, mainly jet milling and spray drying, will also be discussed, including the advantages and limitations of such technologies, based on the authors' industry expertise. Lastly, the paper will highlight the challenges and considerations for encapsulating both spray dried and jet milled powders. Unlike existing literature, this paper offers a unified framework that bridges preclinical, formulation, manufacturing, and encapsulation considerations, providing a practical tool for newcomers.

The (re)emergence of aerosol delivery: Treatment of pulmonary diseases and its clinical challenges

Aerosol delivery represents a rapid and non-invasive way to directly reach the lungs while escaping the hepatic first-pass effect. The development of pulmonary drugs for respiratory diseases such as cystic fibrosis, lung infections, pulmonary fibrosis or lung cancer requires an enhanced understanding of the relationships between the natural physiology of the respiratory system and the pathophysiology of these conditions. This knowledge is crucial to better predict and thereby control drug deposition. Moreover, aerosol administration faces several challenges, including the pulmonary tract, immune system, mucociliary clearance, the presence of fluid on the airway surfaces, and, in some cases, bacterial colonisation. Each of them directly influences on the bioavailability of the active molecule. In addition to these challenges, particle size and the device used to administer the treatment are critical factors that can significantly impact the biodistribution of the drugs. Nanoparticles are very promising in the development of new formulations for aerosol drug delivery, as they can be fine-tuned to reach the entire pulmonary tract and overcome the difficulties encountered along the way. However, to properly assess drug delivery, preclinical studies need to be more thorough to efficiently enhance drug delivery.

Poloxamer 188 stabilized poly (ε-caprolactone) microspheres of voriconazole for targeting pulmonary aspergillosis

AIM

Voriconazole (VRZ) is highly effective in treating invasive pulmonary aspergillosis (IPA), in addition to hepatotoxicity. Therefore, the current study focuses on the development and characterization of voriconazole-loaded microspheres (VRZ@PCL MSPs) to augment pulmonary localization and antifungal efficacy.

METHODS

VRZ@PCL MSPs were fabricated by using the o/w emulsion method. The optimized F3VRZ@PCL MSPs were subjected to physicochemical characterization, in vitro release, hemocompatibility, antifungal efficacy as well as pharmacokinetic and biodistribution evaluation.

RESULTS

The optimized F3VRZ@MSPs exhibited a particle size (10.90 ± 2.61 µm), entrapment efficiency (19.35 ± 2.47%), drug loading (3.22 ± 0.41%) with sustained release behavior up to 24 h and hemocompatibility upto 50 µg/mL. Results of antifungal testing indicated the superior antifungal potential of F3VRZ@PCL MSPs as compared to free VRZ and nystatin. In vivo pharmacokinetic evaluation in Sprague-Dawley rats displayed 12.5-fold and 4.5-fold increments, respectively, in t1/2 and AUC0-t of F3VRZ@PCL MSPs as compared to free VRZ. Moreover, F3VRZ@PCL MSPs displayed relatively higher lung targeting with a drug targeting index (DTI) of 0.213 as compared to DTI of 0.037 of free VRZ.

CONCLUSION

In conclusion, F3VRZ@PCL MSPs offer a promising approach for sustained and targeted delivery of VRZ and hold the potential to offer high therapeutic efficacy in the treatment of IPA.

Inhalable Mucociliary-On-Chip System Revealing Pulmonary Clearance Dynamics in Nanodrug Delivery

The development of a inhaled nanodrug delivery assessment platform is crucial for advancing treatments for chronic lung diseases. Traditional in vitro models and commercial aerosol systems fail to accurately simulate the complex human respiratory patterns and mucosal barriers. To address this, we have developed the breathing mucociliary-on-a-chip (BMC) platform, which replicates mucociliary clearance and respiratory dynamics in vitro. This platform allows for precise analysis of drug deposition and penetration, providing critical insights into how liposomes and other nanocarriers interact with lung tissues under various airflow conditions. Our results reveal that liposomes penetrate deeper into the cellular layer under high shear stress, with both static and dynamic airflows distinctly affecting their drug release rates. The BMC platform integrates dynamic inhalation systems with mucociliary clearance functionality, enabling a comprehensive evaluation of drug delivery efficacy. This approach highlights the importance of airflow dynamics in optimizing inhalable nanodrug delivery systems, improving nanocarrier design, and tailoring drug dosages and release strategies. The BMC platform represents a significant advancement in the field of inhaled nanodrug delivery, offering a more accurate and reliable method for assessing the performance of therapies. By providing a detailed understanding of drug interactions with lung tissues, this platform supports the development of personalized inhaled therapies and offers promising strategies for treating pulmonary diseases and advancing nanodrug development.

Pulmonary-delivered Anticalin Jagged-1 antagonists reduce experimental airway mucus hyperproduction and obstruction

Mucus hypersecretion and mucus obstruction are pathogenic features in many chronic lung diseases directly linked to disease severity, exacerbation, progression, and mortality. The Jagged-1/Notch pathway is a promising therapeutic target that regulates secretory and ciliated cell trans-differentiation in the lung. However, the Notch pathway is also required in various other organs. Hence, pulmonary delivery of therapeutic agents is a promising approach to target this pathway while minimizing systemic exposure. Using Anticalin technology, Jagged-1 Anticalin binding proteins were generated and engineered to potent and selective inhalable Jagged-1 antagonists. Their therapeutic potential to reduce airway mucus hyperproduction and obstruction was investigated ex vivo and in vivo. In primary airway cell cultures grown at an air-liquid interface and stimulated with inflammatory cytokines, Jagged-1 Anticalin binding proteins reduced both mucin gene expression and mucous cell metaplasia. In vivo, prophylactic and therapeutic treatment with a pulmonary-delivered Jagged-1 Anticalin binding protein reduced mucous cell metaplasia, epithelial thickening, and airway mucus hyperproduction in IL-13 and house dust mite allergen-challenged mice, respectively. Furthermore, in a transgenic mouse model with pathophysiologic features of cystic fibrosis and chronic obstructive pulmonary disease (COPD), pulmonary-delivered Jagged-1 Anticalin binding protein reduced hallmarks of airway mucus obstruction. In all in vivo models, a reduction of mucous cells with a concomitant increase of ciliated cells was observed. Collectively, these findings support Jagged-1 antagonists' therapeutic potential for patients with muco-obstructive lung diseases and the feasibility of targeting the Jagged-1/Notch pathway by inhalation.NEW & NOTEWORTHY Airway mucus drives severity and mortality in diverse chronic lung diseases. The Jagged-1/Notch pathway controls the balance of ciliated versus mucous cells, but targeting the pathway systemically carries the risk of side effects. Here we developed novel, Anticalin-derived, pulmonary-delivered Jagged-1 antagonists, to inhibit airway mucus hyperproduction and obstruction in chronic lung diseases. Our preclinical data demonstrate the effectiveness of these antagonists in diminishing secretory cell and mucus levels and alleviating hallmarks of mucus obstruction.

Disordered mesoporous silica particles: an emerging platform to deliver proteins to the lungs

Pulmonary delivery and formulation of biologics are among the more complex and growing scientific topics in drug delivery. We herein developed a dry powder formulation using disordered mesoporous silica particles (MSP) as the sole excipient and lysozyme, the most abundant antimicrobial proteins in the airways, as model protein. The MSP had the optimal size for lung deposition (2.43 ± 0.13 µm). A maximum lysozyme loading capacity (0.35 mg/mg) was achieved in 150 mM PBS, which was seven times greater than that in water. After washing and freeze-drying, we obtained a dry powder consisting of spherical, non-aggregated particles, free from residual buffer, or unabsorbed lysozyme. The presence of lysozyme was confirmed by TGA and FT-IR, while N2 adsorption/desorption and SAXS analysis indicate that the protein is confined within the internal mesoporous structure. The dry powder exhibited excellent aerodynamic performance (fine particle fraction <5 µm of 70.32%). Lysozyme was released in simulated lung fluid in a sustained kinetics and maintaining high enzymatic activity (71-91%), whereas LYS-MSP were shown to degrade into aggregated nanoparticulate microstructures, reaching almost complete dissolution (93%) within 24 h. MSPs were nontoxic to in vitro lung epithelium. The study demonstrates disordered MSP as viable carriers to successfully deliver protein to the lungs, with high deposition and retained activity.

Biologics in Asthma: Emerging Biologics

Advances in our understanding of asthma pathophysiology have led to the advent of multiple targeted asthma therapies such as biologics. However, partial response to biologics occurs, indicating residual disease activity in some patients. Hence, there exists a need for new therapies that focus on novel pathways, alongside perhaps evaluation of combination biologic therapies and modulators of downstream cytokine activation. Therefore, although our current focus is on biologics; it is critical to take a more holistic approach including consideration for nonbiologic therapies that have the potential to significantly advance asthma care.

Enhancing peptide and PMO delivery to mouse airway epithelia by chemical conjugation with the amphiphilic peptide S10

Delivery of antisense oligonucleotides (ASOs) to airway epithelial cells is arduous due to the physiological barriers that protect the lungs and the endosomal entrapment phenomenon, which prevents ASOs from reaching their intracellular targets. Various delivery strategies involving peptide-, lipid-, and polymer-based carriers are being investigated, yet the challenge remains. S10 is a peptide-based delivery agent that enables the intracellular delivery of biomolecules such as GFP, CRISPR-associated nuclease ribonucleoprotein (RNP), base editor RNP, and a fluorescent peptide into lung cells after intranasal or intratracheal administrations to mice, ferrets, and rhesus monkeys. Herein, we demonstrate that covalently attaching S10 to a fluorescently labeled peptide or a functional splice-switching phosphorodiamidate morpholino oligomer improves their intracellular delivery to airway epithelia in mice after a single intranasal instillation. Data reveal a homogeneous delivery from the trachea to the distal region of the lungs, specifically into the cells lining the airway. Quantitative measurements further highlight that conjugation via a disulfide bond through a pegylated (PEG) linker was the most beneficial strategy compared with direct conjugation (without the PEG linker) or conjugation via a permanent thiol-maleimide bond. We believe that S10-based conjugation provides a great strategy to achieve intracellular delivery of peptides and ASOs with therapeutic properties in lungs.

Efficient Nebulization and Pulmonary Biodistribution of Polymeric Nanocarriers in an Acute Lung Injury Preclinical Model

Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by acute hypoxemic respiratory failure. Pneumonia and sepsis are the most common causes, turning ARDS into a critical public health problem. Despite recent advances in pharmacological strategies, clinical trials have not demonstrated a reduction in ARDS-associated mortality. This is in part connected to the singularity of the pulmonary physiological barrier, which hampers drug delivery, specifically at distal areas. To this aim, the use of polymeric nanocarriers as a platform for the efficient delivery of therapeutics to the lungs by nebulization is introduced. Herein, poly(lactic-co-glycolic acid) (PLGA) nanocapsules (NCs) loaded with human serum albumin, as an inhalable nanotherapeutic are prepared. The production of stable NCs aerosols in the inhalable range is achieved using a commercial device, while the nanocarrier's physicochemical parameters are only minimally altered after nebulization. Importantly, in vivo studies with healthy and acute lung injury animals show that after inhalation, the NCs are homogeneously distributed throughout the lungs, arriving at the distal areas. The NCs are internalized by alveolar type II cells, avoiding macrophage-mediated lung clearance. These features make the PLGA NCs excellent vehicles for noninvasive pulmonary delivery, facilitating a ready-to-be-used nanomedicine.

Research Progress of Metal-Organic Frameworks as Drug Delivery Systems

Metal-organic frameworks (MOFs) are composite crystalline materials created through the coordination of metal ions and organic ligands. MOFs have attracted extensive attention in the biomedical field based on the advantages of internal porosity, customizable porosity, and facile surface modification. This review examines the utilization of MOFs in drug delivery systems, focusing on the research progress from the aspects of coloading drug systems, intelligent responsive carriers, biological macromolecule stabilizers, self-driving micro/nanomotors, and multifunctional living carriers. In addition, the current challenges the research faces are also discussed. The review aims to provide a reference for the further application of MOFs as advanced drug delivery systems.

Inhalational Drug Devices: Revisiting the Linchpin of Asthma Management

Asthma remains a prevalent condition among all age groups globally. First-line treatment requires the delivery of medications into the distal respiratory tract via inhalers. Using appropriate inhaler techniques is a significant challenge in achieving disease control. A variety of inhalers are available for treating asthma, and selecting the appropriate inhaler type for any given patient is crucial to achieving and maintaining symptomatic control. This review will discuss the anatomy and physiology behind drug delivery via inhalers, the types of inhalers currently available for use, nebulizers, and future directions in the delivery of inhaled medications for asthma.

Highly Drug-Loaded Nanoaggregate Microparticles for Pulmonary Delivery of Cyclosporin A

Introduction

Nanoparticles have the advantages of improving the solubility of poorly water-soluble drugs, facilitating the drug across biological barriers, and reducing macrophage phagocytosis in pulmonary drug delivery. However, nanoparticles have a small aerodynamic particle size, which makes it difficult to achieve optimal deposition when delivered directly to the lungs. Therefore, delivering nanoparticles to the lungs effectively has become a popular research topic.

Methods

Nanoaggregate microparticles were used as a pulmonary drug delivery strategy for the improvement of the bioavailability of cyclosporine A (CsA). The nanoaggregate microparticles were prepared with polyvinyl pyrrolidone (PVP) as the excipient by combining the anti-solvent method and spray drying process. The physicochemical properties, aerodynamic properties, in vivo pharmacokinetics and inhalation toxicity of nanoaggregate microparticles were systematically evaluated.

Results

The optimal nanoparticles exhibited mainly spherical shapes with the particle size and zeta potential of 180.52 nm and -19.8 mV. The nanoaggregate microparticles exhibited irregular shapes with the particle sizes of less than 1.6 µm and drug loading (DL) values higher than 70%. Formulation NM-2 as the optimal nanoaggregate microparticles was suitable for pulmonary drug delivery and probably deposited in the bronchiole and alveolar region, with FPF and MMAD values of 89.62% and 1.74 μm. In addition, inhaled NM-2 had C max and AUC0-∞ values approximately 1.7-fold and 1.8-fold higher than oral cyclosporine soft capsules (Neoral®). The inhalation toxicity study suggested that pulmonary delivery of NM-2 did not result in lung function damage, inflammatory responses, or tissue lesions.

Conclusion

The novel nanoaggregate microparticles for pulmonary drug delivery could effectively enhance the relative bioavailability of CsA and had great potential for clinical application.

High-loading cannabidiol powders for inhalation

Limited attempts have been made previously to develop high-loading CBD inhalable powders, which are essential for high dose delivery. Therefore, this study aimed to develop and characterise inhalable powders with ≥ 95 % w/w CBD by wet ball milling. The effects of magnesium stearate (2 % and 5 %) and inhaler resistance (low-resistance and high-resistance RS01 inhalers) on aerosol performance were also compared. Wet ball milling produced CBD powders with > 50 % production yield. The milled particles showed irregular shapes. The powders were crystalline with minimal amorphous content, low residual solvent level (<1%), and low moisture sorption (<4%). Magnesium stearate improved both the emitted and fine particle fractions. The aerodynamic particle size distribution of the formulations differed between the low-resistance and high-resistance RS01 inhalers. The latter decreased throat deposition but increased inhaler retention. The dissolution profiles showed that all three formulations released CBD steadily and plateaued at 30 min. The best scenario was CBD with 5 % magnesium stearate dispersed from the high resistance RS01 inhaler, showing the highest FPF with the lowest throat deposition. This combination may be tested in vivo in the future to investigate its pharmacokinetic profile.

Validation of the Absorption-Enhancing Ability of Oligoarginines Grafted onto a Backbone of Hyaluronic Acid through Animal Studies from Rodents to Primates

The purpose of our research is to develop functional additives that enhance mucosal absorption of biologics, such as peptide/protein and antibody drugs, to provide their non-to-poor invasive dosage forms self-managed by patients. Our previous in vivo and in vitro studies demonstrated that the intranasal absorption of biologics in mice was significantly improved when coadministered with oligoarginines anchored chemically to hyaluronic acid via a glycine spacer, presumably through syndecan-4-mediated macropinocytosis under activation by oligoarginines. The present mouse experiments first revealed that diglycine-L-tetraarginine-linked hyaluronic acid significantly enhanced the intranasal absorption of sulpiride, which is a poor-absorptive organic compound with a low molecular weight. However, similar enhancement was not observed for levofloxacin, which has a similarly low molecular weight but is a well-absorptive organic compound, probably because its absorption was mostly dominated by passive diffusion. The subsequent monkey experiments revealed that there was no species difference in the absorption-enhancing ability of diglycine-L-tetraarginine-linked hyaluronic acid for not only organic compounds but also biologics. This was presumably because the expression levels of endocytosis-associated membrane proteins on the nasal mucosa in monkeys were almost equivalent to those in mice, and poorly membrane-permeable/membrane-impermeable drugs were mainly absorbed via syndecan-4-mediated macropinocytosis, regardless of animal species. Drug concentrations in the brain assessed in mice and monkeys and those in the cerebral spinal fluids (CSFs) assessed in monkeys indicated that drugs would be delivered from the systemic circulation to the central nervous system by crossing the blood-brain and the blood-CSF barriers under coadministration with the hyaluronic acid derivative. In line with our original hypothesis, this new set of data supported that our oligoarginine-linked hyaluronic acid would locally perform on the mucosal surface and enhance the membrane permeation of drugs under its colocalization.

Isolation of human antibodies against influenza B neuraminidase and mechanisms of protection at the airway interface

Influenza B viruses (IBVs) comprise a substantial portion of the circulating seasonal human influenza viruses. Here, we describe the isolation of human monoclonal antibodies (mAbs) that recognized the IBV neuraminidase (NA) glycoprotein from an individual following seasonal vaccination. Competition-binding experiments suggested the antibodies recognized two major antigenic sites. One group, which included mAb FluB-393, broadly inhibited IBV NA sialidase activity, protected prophylactically in vivo, and bound to the lateral corner of NA. The second group contained an active site mAb, FluB-400, that broadly inhibited IBV NA sialidase activity and virus replication in vitro in primary human respiratory epithelial cell cultures and protected against IBV in vivo when administered systemically or intranasally. Overall, the findings described here shape our mechanistic understanding of the human immune response to the IBV NA glycoprotein through the demonstration of two mAb delivery routes for protection against IBV and the identification of potential IBV therapeutic candidates.

Distribution and suitability of pulmonary surfactants as a vehicle for topically applied antibodies in healthy and SARS-CoV-2 infected rodent lungs

The use of natural pulmonary surfactants (PS) as a drug delivery vehicle for biologics is a more recent therapeutic modality. Herein, we tested different contents of PS regarding their physicochemical properties under stress conditions. The PS content of 12.25 mg/ml (Formulation B) showed desired properties such as an isotonic osmolality ∼300 mOsm/kg and an acceptable viscosity of 8.61 cSt, being lower than in commercially available PS solutions. Formulation B passed the specifications of surface lowering capacities of >80 % total lung capacity and physiologically desired formulation properties were independent of the antibody used in the composition. The identified formulation showed the capability of significantly increasing the oxygen saturation in ex vivo isolated perfused rat lungs, compared to a control and up to 30 min post lavage. In the in vivo setting, we showed that intratracheal administration of a human mAB with and without pulmonary surfactant led to higher amounts of delivered antibody within the alveolar tissue compared to intravenous administration. The antibody with the PS formulation remained longer in the alveolar tissues than the antibody without the PS formulation. Further, SARS-CoV-2 infected Golden Syrian hamsters showed that the intranasally applied antibody reached the site of infection in the alveoli and could be detected in the alveolar region 24 h after the last administration. With this work, we demonstrated that pulmonary surfactants can be used as a pulmonary drug delivery mechanism for antibodies and may subsequently improve the antibody efficacy by increasing the residence time at the desired site of action in the alveolar tissue.

Pulmonary inhalation for disease treatment: Basic research and clinical translations

Pulmonary drug delivery has the advantages of being rapid, efficient, and well-targeted, with few systemic side effects. In addition, it is non-invasive and has good patient compliance, making it a highly promising drug delivery mode. However, there have been limited studies on drug delivery via pulmonary inhalation compared with oral and intravenous modes. This paper summarizes the basic research and clinical translation of pulmonary inhalation drug delivery for the treatment of diseases and provides insights into the latest advances in pulmonary drug delivery. The paper discusses the processing methods for pulmonary drug delivery, drug carriers (with a focus on various types of nanoparticles), delivery devices, and applications in pulmonary diseases and treatment of systemic diseases (e.g., COVID-19, inhaled vaccines, diagnosis of the diseases, and diabetes mellitus) with an updated summary of recent research advances. Furthermore, this paper describes the applications and recent progress in pulmonary drug delivery for lung diseases and expands the use of pulmonary drugs for other systemic diseases.

COVID-19 cooling: Nanostrategies targeting cytokine storm for controlling severe and critical symptoms

As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to wreak havoc worldwide, the "Cytokine Storm" (CS, also known as the inflammatory storm) or Cytokine Release Syndrome has reemerged in the public consciousness. CS is a significant contributor to the deterioration of infected individuals. Therefore, CS control is of great significance for the treatment of critically ill patients and the reduction of mortality rates. With the occurrence of variants, concerns regarding the efficacy of vaccines and antiviral drugs with a broad spectrum have grown. We should make an effort to modernize treatment strategies to address the challenges posed by mutations. Thus, in addition to the requirement for additional clinical data to monitor the long-term effects of vaccines and broad-spectrum antiviral drugs, we can use CS as an entry point and therapeutic target to alleviate the severity of the disease in patients. To effectively combat the mutation, new technologies for neutralizing or controlling CS must be developed. In recent years, nanotechnology has been widely applied in the biomedical field, opening up a plethora of opportunities for CS. Here, we put forward the view of cytokine storm as a therapeutic target can be used to treat critically ill patients by expounding the relationship between coronavirus disease 2019 (COVID-19) and CS and the mechanisms associated with CS. We pay special attention to the representative strategies of nanomaterials in current neutral and CS research, as well as their potential chemical design and principles. We hope that the nanostrategies described in this review provide attractive treatment options for severe and critical COVID-19 caused by CS.

An Updated Review on Nanoemulsion: Factory for Food and Drug Delivery

BACKGROUND

A nanoemulsion is a colloidal system of small droplets dispersed in another liquid. It has attracted considerable attention due to its unique properties and various applications. Throughout this review, we provide an overview of nanoemulsions and how they can be applied to various applications such as drug delivery, food applications, and pesticide formulations.

OBJECTIVE

This updated review aims to comprehensively overview nanoemulsions and their applications as a versatile platform for drug delivery, food applications, and pesticide formulations.

METHODS

Research relevant scientific literature across various databases, including PubMed, Scopus, and Web of Science. Suitable keywords for this purpose include "nanoemulsion," "drug delivery," and "food applications." Ensure the search criteria include recent publications to ensure current knowledge is included.

RESULTS

Several benefits have been demonstrated in the delivery of drugs using nanoemulsions, including improved solubility, increased bioavailability, and controlled delivery. Nanoemulsions have improved some bioactive compounds in food applications, including vitamins and antioxidants. At the same time, pesticide formulations based on nanoemulsions have also improved solubility, shelf life, and effectiveness.

CONCLUSION

The versatility of nanoemulsions makes them ideal for drug delivery, food, and pesticide formulation applications. These products are highly soluble, bioavailable, and targeted, providing significant advantages. More research and development are required to implement nanoemulsion-based products on a commercial scale.

Advanced Formulation Approaches for Proteins

Proteins and peptides are highly desirable as therapeutic agents, being highly potent and specific. However, there are myriad challenges with processing them into patient-friendly formulations: they are often unstable and have a tendency to aggregate or degrade upon storage. As a result, the vast majority of protein actives are delivered parenterally as solutions, which has a number of disadvantages in terms of cost, accessibility, and patient experience. Much work has been undertaken to develop new delivery systems for biologics, but to date this has led to relatively few products on the market. In this chapter, we review the challenges faced when developing biologic formulations, discuss the technologies that have been explored to try to overcome these, and consider the different delivery routes that can be applied. We further present an overview of the currently marketed products and assess the likely direction of travel in the next decade.

Acute exacerbation of bronchial asthma with infective focus treated with holistic Ayurveda approach: A case report

While there are numerous published clinical trials investigating the efficacy of Ayurveda in managing bronchial asthma, a paucity of published case reports, case series, or randomized controlled trials (RCTs) concerning Basti (medicated enema) therapy in conjunction with Dhumapana (fumigation therapy) exists on PubMed.This scarcity of data hinders the comprehensive evaluation of this specific Ayurvedic approach for asthma management. A 69-year-old female patient with a known case of bronchial asthma and hypertension presented with complaints of breathlessness on and off for 3 years, cough, urgency of micturition, constipation for 7 days, and fever for 3 days. The patient was treated according to the treatment principles of Tamakshwas (bronchial asthma) and Jwara (fever). Basti, Dhumapana, and oral Ayurvedic formulations were administered. Significant improvements in symptoms, the mMRC dyspnea scale, and the pulmonary function test were observed. This case provides new insight into clinical diagnosis and management through gut modulation in respiratory diseases and vice versa.

Nano vs Resistant Tuberculosis: Taking the Lung Route

Tuberculosis (TB) is among the top 10 infectious diseases worldwide. It is categorized among the leading killer diseases that are the reason for the death of millions of people globally. Although a standardized treatment regimen is available, non-adherence to treatment has increased multi-drug resistance (MDR) and extensive drug-resistant (XDR) TB development. Another challenge is targeting the death of TB reservoirs in the alveoli via conventional treatment. TB Drug resistance may emerge as a futuristic restraint of TB with the scarcity of effective Anti-tubercular drugs. The paradigm change towards nano-targeted drug delivery systems is mostly due to the absence of effective therapy and increased TB infection recurrent episodes with MDR. The emerging field of nanotechnology gave an admirable opportunity to combat MDR and XDR via accurate diagnosis with effective treatment. The new strategies targeting the lung via the pulmonary route may overcome the new incidence of MDR and enhance patient compliance. Therefore, this review highlights the importance and recent research on pulmonary drug delivery with nanotechnology along with prevalence, the need for the development of nanotechnology, beneficial aspects of nanomedicine, safety concerns of nanocarriers, and clinical studies.

Absorption enhancer approach for protein delivery by various routes of administration: a rapid review

As bioactive molecules, peptides and proteins are essential in living organisms, including animals and humans. Defects in their function lead to various diseases in humans. Therefore, the use of proteins in treating multiple diseases, such as cancers and hepatitis, is increasing. There are different routes to administer proteins, which have limitations due to their large and hydrophilic structure. Another limitation is the presence of biological and lipophilic membranes that do not allow proteins to pass quickly. There are different strategies to increase the absorption of proteins from these biological membranes. One of these strategies is to use compounds as absorption enhancers. Absorption enhancers are compounds such as surfactants, phospholipids and cyclodextrins that increase protein passage through the biological membrane and their absorption by different mechanisms. This review focuses on using other absorption enhancers and their mechanism in protein administration routes.

An ACE2 decamer viral trap as a durable intervention solution for current and future SARS-CoV

The capacity of SARS-CoV-2 to evolve poses challenges to conventional prevention and treatment options such as vaccination and monoclonal antibodies, as they rely on viral receptor binding domain (RBD) sequences from previous strains. Additionally, animal CoVs, especially those of the SARS family, are now appreciated as a constant pandemic threat. We present here a new antiviral approach featuring inhalation delivery of a recombinant viral trap composed of ten copies of angiotensin-converting enzyme 2 (ACE2) fused to the IgM Fc. This ACE2 decamer viral trap is designed to inhibit SARS-CoV-2 entry function, regardless of viral RBD sequence variations as shown by its high neutralization potency against all known SARS-CoV-2 variants, including Omicron BQ.1, BQ.1.1, XBB.1 and XBB.1.5. In addition, it demonstrates potency against SARS-CoV-1, human NL63, as well as bat and pangolin CoVs. The multivalent trap is effective in both prophylactic and therapeutic settings since a single intranasal dosing confers protection in human ACE2 transgenic mice against viral challenges. Lastly, this molecule is stable at ambient temperature for more than twelve weeks and can sustain physical stress from aerosolization. These results demonstrate the potential of a decameric ACE2 viral trap as an inhalation solution for ACE2-dependent coronaviruses of current and future pandemic concerns.

The role of airway mucus and diseased pulmonary epithelium on the absorption of inhaled antibodies

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.

Systemically Administered Anti-uPAR Antibody Plasma and Lung ELF Pharmacokinetics Characterized by Minimal Lung PBPK Model

Antibody-based therapeutics have recently gained keen attention for the treatment of pulmonary indications. However, systemically administered antibody exposure in the lungs needs to be better understood and remains a topic of interest. In this study, we evaluated the exposure of two different uPAR (urokinase-type plasminogen activator receptor) targeting full-length monoclonal IgGs in plasma and lung epithelial lining fluid (ELF) of mice after IP and IV administration. Antibody AK17 exhibited linear pharmacokinetics (PK) in plasma and ELF at 3 and 30 mg/kg single IV dose. The average plasma and ELF half-lives for AK17 and AK21 ranged between ~321-411 h and ~230-345 h, respectively, indicating sustained systemic and lung exposure of antibodies. The average ELF to the plasma concentration ratio of antibodies was ~0.01 and ~0.03 with IP and IV dosing, respectively, over 2 weeks post single dose. We simultaneously characterized plasma and ELF PK of antibody in mice by developing a minimal lung PBPK model for antibody. This model reasonably captured the plasma and ELF PK data while estimating three parameters. The model accounts for the convective transport of antibody into the tissues via blood and lymph flow. FcRn-mediated transcytosis was incorporated into the model for antibody distribution across the lung epithelial barrier. This model serves as a platform to predict the pulmonary PK of systemically administered antibodies and to support optimal dose selection for desired exposure in the lungs as the site of action.

Screening of Cyclodextrins in the Processing of Buserelin Dry Powders for Inhalation Prepared by Spray Freeze-Drying

Purpose

In this study, we prepared inhalable buserelin microparticles using the spray freeze-drying (SFD) method for pulmonary drug delivery. Raffinose as a cryoprotectant carrier was combined with two levels of five different cyclodextrins (CDs) and then processed by SFD.

Methods

Dry powder diameters were evaluated by laser light scattering and morphology was determined by scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis were utilized for the determination of crystalline structures. The aerodynamic properties of the spray freeze-dried powders were evaluated by twin stage impinger (TSI) and the stability of prepared samples was assessed under normal and accelerated conditions.

Results

The prepared powders were mostly porous spheres and the size of microparticles ranged from 9.08 to 13.53 μm, which are suitable as spray-freeze dried particles. All formulations showed amorphous structure confirmed by DSC and XRD. The aerosolization performance of the formulation containing buserelin, raffinose and 5% beta-cyclodextrin (β-CD), was the highest and its fine particle fraction (FPF) was 69.38%. The more circular and separated structures were observed in higher concentrations of CDs, which were compatible with FPFs. The highest stability was obtained in the formulation containing hydroxypropyl beta-cyclodextrin (HP-β-16. CD) 5%. On the contrary, sulfobutylether beta-cyclodextrin (SBE-β-CD) 5% bearing particles showed the least stability.

Conclusion

By adjusting the type and ratio of CDs in the presence of raffinose, the prepared formulations could effectively enhance the aerosolization and stability of buserelin. Therefore, they can be proposed as a suitable career for lung drug delivery.

Stimuli-Responsive Hydrogels for Protein Delivery

Proteins and peptides are potential therapeutic agents, but their physiochemical properties make their use as drug substances challenging. Hydrogels are hydrophilic polymeric networks that can swell and retain high amounts of water or biological fluids without being dissolved. Due to their biocompatibility, their porous structure, which enables the transport of various peptides and proteins, and their protective effect against degradation, hydrogels have gained prominence as ideal carriers for these molecules' delivery. Particularly, stimuli-responsive hydrogels exhibit physicochemical transitions in response to subtle modifications in the surrounding environment, leading to the controlled release of entrapped proteins or peptides. This review is focused on the application of these hydrogels in protein and peptide delivery, including a brief overview of therapeutic proteins and types of stimuli-responsive polymers.

Lung Toxicity and Molecular Mechanisms of Lead-Based Perovskite Nanoparticles in the Respiratory System

Lead-based perovskite nanoparticles (Pb-PNPs) have found extensive applications across diverse fields. However, because of poor stability and relatively strong water solubility, the potential toxicity of Pb-PNPs released into the environment during their manufacture, usage, and disposal has attracted significant attention. Inhalation is a primary route through which human exposure to Pb-PNPs occurs. Herein, the toxic effects and underlying molecular mechanisms of Pb-PNPs in the respiratory system are investigated. The in vitro cytotoxicity of CsPbBr3 nanoparticles in BEAS-2B cells is studied using multiple bioassays and electron microscopy. CsPbBr3 nanoparticles of different concentrations induce excessive oxidative stress and cell apoptosis. Furthermore, CsPbBr3 nanoparticles specifically recruit the TGF-β1, which subsequently induces epithelial-mesenchymal transition. In addition, the biodistribution and lung toxicity of representative CsPbBr3 nanoparticles in ICR mice are investigated following intranasal administration. These findings indicate that CsPbBr3 nanoparticles significantly induce pulmonary inflammation and epithelial-mesenchymal transition and can even lead to pulmonary fibrosis in mouse models. Above findings expose the adverse effects and molecular mechanisms of Pb-PNPs in the lung, which broadens the safety data of Pb-PNPs.

Respiratory delivery of passive immunotherapies for SARS-CoV-2 prophylaxis and therapy

Convalescent plasma has been extensively tested during the COVID-19 pandemic as a transfusion product. Similarly, monoclonal antibodies have been largely administered either intravenously or intramuscularly. Nevertheless, when used against a respiratory pathogen, respiratory delivery is preferable to maximize the amount of antibody that reaches the entry door in order to prevent sustained viral multiplication. In this narrative review, we review the different types of inhalation device and summarize evidence from animal models and early clinical trials supporting the respiratory delivery (for either prophylactic or therapeutic purposes) of convalescent plasma or monoclonal antibodies (either full antibodies, single-chain variable fragments, or camelid-derived monoclonal heavy-chain only antibodies). Preliminary evidences from animal models suggest similar safety and noninferior efficacy, but efficacy evaluation from clinical trials is still limited.

Aerosol pulmonary immune engineering

Aerosolization of immunotherapies poses incredible potential for manipulating the local mucosal-specific microenvironment, engaging specialized pulmonary cellular defenders, and accessing mucosal associated lymphoid tissue to redirect systemic adaptive and memory responses. In this review, we breakdown key inhalable immunoengineering strategies for chronic, genetic, and infection-based inflammatory pulmonary disorders, encompassing the historic use of immunomodulatory agents, the transition to biological inspired or derived treatments, and novel approaches of complexing these materials into drug delivery vehicles for enhanced release outcomes. Alongside a brief description of key immune targets, fundamentals of aerosol drug delivery, and preclinical pulmonary models for immune response, we survey recent advances of inhaled immunotherapy platforms, ranging from small molecules and biologics to particulates and cell therapies, as well as prophylactic vaccines. In each section, we address the formulation design constraints for aerosol delivery as well as advantages for each platform in driving desirable immune modifications. Finally, prospects of clinical translation and outlook for inhaled immune engineering are discussed.

Systemic Protein Delivery via Inhalable Liposomes: Formulation and Pharmacokinetics

The enormous and thin alveolar epithelium is an attractive site for systemic protein delivery. Considering the excellent biocompatibility of phospholipids with endogenous pulmonary surfactant, we engineered dimyristoylphosphatidylcholine (DMPC)-based liposomes for pulmonary administration, using Cy5.5-labeled bovine serum albumin (BSA-Cy5.5) as a model protein payload. The level of cholesterol (Chol) and surface modification with PEG in inhalable liposomes were optimized iteratively based on the encapsulation efficiency, the release kinetics in the simulated lung fluid, and the uptake in murine RAW 264.7 macrophages. The plasma pharmacokinetics of BSA-Cy5.5-encapsulated liposomes with the composition of DMPC/Chol/PEG at 85:10:5 (molar ratio) was studied in mice following intratracheal aerosolization, in comparison with that of free BSA-Cy5.5 solution. The biodisposition of BSA-Cy5.5 was continuously monitored using whole-body near-infrared (NIR) fluorescence imaging for 10 days. We found that the systemic bioavailability of BSA-Cy5.5 from inhaled liposomes was 22%, which was notably higher than that of inhaled free BSA-Cy5.5. The mean residence time of BSA-Cy5.5 was markedly prolonged in mice administered intratracheally with liposomal BSA-Cy5.5, which is in agreement with the NIR imaging results. Our work demonstrates the great promise of inhalable DMPC-based liposomes to achieve non-invasive systemic protein delivery.

Barriers for orally inhaled therapeutic antibodies

INTRODUCTION

Respiratory diseases represent a worldwide health issue. The recent Sars-CoV-2 pandemic, the burden of lung cancer, and inflammatory respiratory diseases urged the development of innovative therapeutic solutions. In this context, therapeutic antibodies (Abs) offer a tremendous opportunity to benefit patients with respiratory diseases. Delivering Ab through the airways has been demonstrated to be relevant to improve their therapeutic index. However, few inhaled Abs are on the market.

AREAS COVERED

This review describes the different barriers that may alter the fate of inhaled therapeutic Abs in the lungs at steady state. It addresses both physical and biological barriers and discusses the importance of taking into consideration the pathological changes occurring during respiratory disease, which may reinforce these barriers.

EXPERT OPINION

The pulmonary route remains rare for delivering therapeutic Abs, with few approved inhaled molecules, despite promising evidence. Efforts must focus on the intertwined barriers associated with lung diseases to develop appropriate Ab-formulation-device combo, ensuring optimal Ab deposition in the respiratory tract. Finally, randomized controlled clinical trials should be carried out to establish inhaled Ab therapy as prominent against respiratory diseases.

Inhaled drug delivery for the targeted treatment of asthma

Asthma is a chronic lung disease affecting millions worldwide. While classically acknowledged to result from allergen-driven type 2 inflammatory responses leading to IgE and cytokine production and the influx of immune cells such as mast cells and eosinophils, the wide range in asthmatic pathobiological subtypes lead to highly variable responses to anti-inflammatory therapies. Thus, there is a need to develop patient-specific therapies capable of addressing the full spectrum of asthmatic lung disease. Moreover, delivery of targeted treatments for asthma directly to the lung may help to maximize therapeutic benefit, but challenges remain in design of effective formulations for the inhaled route. In this review, we discuss the current understanding of asthmatic disease progression as well as genetic and epigenetic disease modifiers associated with asthma severity and exacerbation of disease. We also overview the limitations of clinically available treatments for asthma and discuss pre-clinical models of asthma used to evaluate new therapies. Based on the shortcomings of existing treatments, we highlight recent advances and new approaches to treat asthma via inhalation for monoclonal antibody delivery, mucolytic therapy to target airway mucus hypersecretion and gene therapies to address underlying drivers of disease. Finally, we conclude with discussion on the prospects for an inhaled vaccine to prevent asthma.

Strategies for overcoming the biological barriers associated with the administration of inhaled monoclonal antibodies for lung diseases

INTRODUCTION

Monoclonal antibodies (mAbs) should be administered by inhalation rather than parenterally to improve their efficiency in lung diseases. However, the pulmonary administration of mAbs in terms of aerosol technology and the formulation for inhalation is difficult.

AREAS COVERED

The feasible or suitable strategies for overcoming the barriers associated with administering mAbs are described.

EXPERT OPINION

Providing mAbs via inhalation to individuals with lung disorders is still difficult. However, inhalation is a desirable method for mAb delivery. Inhaled mAb production needs to be well thought out. The illness, the patient group(s), the therapeutic molecule selected, its interaction with the biological barriers in the lungs, the formulation, excipients, and administration systems must all be thoroughly investigated. Therefore, to create inhaled mAbs that are stable and efficacious, it will be essential to thoroughly examine the problems linked to instability and protein aggregation. More excipients will also need to be manufactured, expanding the range of formulation design choices. Another crucial requirement is for novel carriers for topical delivery to the lungs since carriers might significantly enhance proteins' stability and pharmacokinetic profile.

Advances in soft mist inhalers

INTRODUCTION

Soft mist inhalers (SMIs) are propellant-free inhalers that utilize mechanical power to deliver single or multiple doses of inhalable drug aerosols in the form of a slow mist to patients. Compared to traditional inhalers, SMIs allow for a longer and slower release of aerosol with a smaller ballistic effect, leading to a limited loss in the oropharyngeal area, whilst requiring little coordination of actuation and inhalation by patients. Currently, the Respimat® is the only commercially available SMI, with several others in different stages of preclinical and clinical development.

AREAS COVERED

The primary purpose of this review is to critically assess recent advances in SMIs for the delivery of inhaled therapeutics.

EXPERT OPINION

Advanced particle formulations, such as nanoparticles which target specific areas of the lung, Biologics, such as vaccines, proteins, and antibodies (which are sensitive to aerosolization), are expected to be generally delivered by SMIs. Furthermore, repurposed drugs are expected to constitute a large share of future formulations to be delivered by SMIs. SMIs can also be employed for the delivery of formulations that target systemic diseases. Finally, digitalizing SMIs would improve patient adherence and provide clinicians with fundamental insights into patients' treatment progress.

Optimization and Characterization of Novel ALCAM-Targeting Antibody Fragments for Transepithelial Delivery

Activated leukocyte cell adhesion molecule (ALCAM) is a cell adhesion molecule that supports T cell activation, leukocyte migration, and (lymph)angiogenesis and has been shown to contribute to the pathology of various immune-mediated disorders, including asthma and corneal graft rejection. In contrast to monoclonal antibodies (mAbs) targeting ALCAM's T cell expressed binding partner CD6, no ALCAM-targeting mAbs have thus far entered clinical development. This is likely linked with the broad expression of ALCAM on many different cell types, which increases the risk of eliciting unwanted treatment-induced side effects upon systemic mAb application. Targeting ALCAM in surface-exposed tissues, such as the lungs or the cornea, by a topical application could circumvent this issue. Here, we report the development of various stability- and affinity-improved anti-ALCAM mAb fragments with cross-species reactivity towards mouse, rat, monkey, and human ALCAM. Fragments generated in either mono- or bivalent formats potently blocked ALCAM-CD6 interactions in a competition ELISA, but only bivalent fragments efficiently inhibited ALCAM-ALCAM interactions in a leukocyte transmigration assay. The different fragments displayed a clear size-dependence in their ability to penetrate the human corneal epithelium. Furthermore, intranasal delivery of anti-ALCAM fragments reduced leukocyte infiltration in a mouse model of asthma, confirming ALCAM as a target for topical application in the lungs.

Functionalized zein nanoparticles targeting neonatal Fc receptor to enhance lung absorption of peptides

Peptides have a distinguished therapeutic potential for several chronic conditions, and more than 80 peptides exist in the global market. However, most of these marketed peptide drugs are currently delivered intravenously or subcutaneously due to their fast degradation and limited absorption through non-invasive routes. The pulmonary route is favored as a non-invasive route. Neonatal Fc receptor (FcRn) is expressed in adult human lungs and has a role in enhancing the pulmonary absorption of monoclonal antibodies. In this work, we developed and characterized candidate protein delivery systems for the pulmonary administration of peptides. The prepared bare and loaded zein nanoparticles (ZNPs), targeted, physically, and covalently PEGylated ZNPs showed hydrodynamic diameters between 137 and 155 nm and a narrow distribution index. Insulin, which was used as a protein model, showed an association efficiency of 72%, while the FcRn-targeted peptide conjugation efficiency was approximately 68%. The physically adsorbed poloxamer 407 on insulin-loaded ZNPs showed slower and controlled insulin release. The in vitro cell culture model consists of the NCI-H441 epithelial cell line, which confirmed its expression of the targeted receptor, FcRn. The safety of ZNPs was verified after incubation with both cell lines of the in vitro pulmonary model, namely NCI-H441 and HPMEC-ST1.6R, for 24 h. It was observed that targeted ZNPs enhanced insulin permeability by showing a higher apparent permeation coefficient than non-targeted ZNPs. Overall, both targeted PEGylated ZNPs showed to be suitable peptide carriers and adequately fit the demands of delivery systems designed for pulmonary administration.

Impact of Organ Impairment on the Pharmacokinetics of Therapeutic Peptides and Proteins

The kidneys and liver are major organs involved in eliminating small-molecule drugs from the body. Characterization of the effects of renal impairment (RI) and hepatic impairment (HI) on pharmacokinetics (PK) have informed dosing in patients with these organ impairments. However, the knowledge about the impact of organ impairment on therapeutic peptides and proteins is still evolving. In this study, we reviewed how often therapeutic peptides and proteins were assessed for the effect of RI and HI on PK, the findings, and the resulting labeling recommendations. RI effects were reported in labeling for 30 (57%) peptides and 98 (39%) proteins and HI effects for 20 (38%) peptides and 55 (22%) proteins. Dose adjustments were recommended for RI in 11 of the 30 (37%) peptides and 10 of the 98 (10%) proteins and for HI in 7 of the 20 (35%) peptides and 3 of the 55 (5%) proteins. Additional actionable labeling includes risk mitigation strategies; for example, some product labels have recommended avoid use or monitor toxicities in patients with HI. Over time, there is an increasing structural diversity of therapeutic peptides and proteins, including the use of non-natural amino acids and conjugation technologies, which suggests a potential need for reassessing the need to evaluate the effect of RI and HI. Herein, we discuss scientific considerations for weighing the risk of PK alteration due to RI or HI for peptide and protein products. We briefly discuss other organs that may affect the PK of peptides and proteins administered via other delivery routes.

Challenges and Opportunities in the Oral Delivery of Recombinant Biologics

Recombinant biological molecules are at the cutting-edge of biomedical research thanks to the significant progress made in biotechnology and a better understanding of subcellular processes implicated in several diseases. Given their ability to induce a potent response, these molecules are becoming the drugs of choice for multiple pathologies. However, unlike conventional drugs which are mostly ingested, the majority of biologics are currently administered parenterally. Therefore, to improve their limited bioavailability when delivered orally, the scientific community has devoted tremendous efforts to develop accurate cell- and tissue-based models that allow for the determination of their capacity to cross the intestinal mucosa. Furthermore, several promising approaches have been imagined to enhance the intestinal permeability and stability of recombinant biological molecules. This review summarizes the main physiological barriers to the oral delivery of biologics. Several preclinical in vitro and ex vivo models currently used to assess permeability are also presented. Finally, the multiple strategies explored to address the challenges of administering biotherapeutics orally are described.

Inhalable Nanoparticle-based Dry Powder Formulations for Respiratory Diseases: Challenges and Strategies for Translational Research

The emergence of novel respiratory infections (e.g., COVID-19) and expeditious development of nanoparticle-based COVID-19 vaccines have recently reignited considerable interest in designing inhalable nanoparticle-based drug delivery systems as next-generation respiratory therapeutics. Among various available devices in aerosol delivery, dry powder inhalers (DPIs) are preferable for delivery of nanoparticles due to their simplicity of use, high portability, and superior long-term stability. Despite research efforts devoted to developing inhaled nanoparticle-based DPI formulations, no such formulations have been approved to date, implying a research gap between bench and bedside. This review aims to address this gap by highlighting important yet often overlooked issues during pre-clinical development. We start with an overview and update on formulation and particle engineering strategies for fabricating inhalable nanoparticle-based dry powder formulations. An important but neglected aspect in in vitro characterization methodologies for linking the powder performance with their bio-fate is then discussed. Finally, the major challenges and strategies in their clinical translation are highlighted. We anticipate that focused research onto the existing knowledge gaps presented in this review would accelerate clinical applications of inhalable nanoparticle-based dry powders from a far-fetched fantasy to a reality.

A new hope? Possibilities of therapeutic IgA antibodies in the treatment of inflammatory lung diseases

Inflammatory lung diseases represent a persistent burden for patients and the global healthcare system. The combination of high morbidity, (partially) high mortality and limited innovations in the last decades, have resulted in a great demand for new therapeutics. Are therapeutic IgA antibodies possibly a new hope in the treatment of inflammatory lung diseases? Current research increasingly unravels the elementary functions of IgA as protector against infections and as modulator of overwhelming inflammation. With a focus on IgA, this review describes the pathological alterations in mucosal immunity and how they contribute to chronic inflammation in the most common inflammatory lung diseases. The current knowledge of IgA functions in the circulation, and particularly in the respiratory mucosa, are summarized. The interplay between neutrophils and IgA seems to be key in control of inflammation. In addition, the hurdles and benefits of therapeutic IgA antibodies, as well as the currently known clinically used IgA preparations are described. The data highlighted here, together with upcoming research strategies aiming at circumventing the current pitfalls in IgA research may pave the way for this promising antibody class in the application of inflammatory lung diseases.

Prophylactic intranasal administration of lipid nanoparticle formulated siRNAs reduce SARS-CoV-2 and RSV lung infection

RNA interference (RNAi) is an emerging and promising therapy for a wide range of respiratory viral infections. This highly specific suppression can be achieved by the introduction of short-interfering RNA (siRNA) into mammalian systems, resulting in the effective reduction of viral load. Unfortunately, this has been hindered by the lack of a good delivery system, especially via the intranasal (IN) route. Here, we have developed an IN siRNA encapsulated lipid nanoparticle (LNP) in vivo delivery system that is highly efficient at targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and respiratory syncytial virus (RSV) lung infection in vivo. Importantly, IN siRNA delivery without the aid of LNPs abolishes anti-SARS-CoV-2 activity in vivo. Our approach using LNPs as the delivery vehicle overcomes the significant barriers seen with IN delivery of siRNA therapeutics and is a significant advancement in our ability to delivery siRNAs. The study presented here demonstrates an attractive alternate delivery strategy for the prophylactic treatment of both future and emerging respiratory viral diseases.

Air-liquid interface (ALI) impact on different respiratory cell cultures

The intranasal route has been receiving greater attention from the scientific community not only for systemic drug delivery but also for the treatment of pulmonary and neurological diseases. Along with it, drug transport and permeability studies across the nasal mucosa have exponentially increased. Nevertheless, the translation of data from in vitro cell lines to in vivo studies is not always reliable, due to the difficulty in generating an in vitro model that resembles respiratory human physiology. Among all currently available methodologies, the air-liquid interface (ALI) method is advantageous to promote cell differentiation and optimize the morphological and histological characteristics of airway epithelium cells. Cells grown under ALI conditions, in alternative to submerged conditions, appear to provide relevant input for inhalation and pulmonary toxicology and complement in vivo experiments. Different methodologies and a variety of materials have been used to induce ALI conditions in primary cells and numerous cell lines. Until this day, with only exploratory results, no consensus has been reached regarding the validation of the ALI method, hampering data comparison. The present review describes the most adequate cell models of airway epithelium and how these models are differently affected by ALI conditions. It includes the evaluation of cellular features before and after ALI, and the application of the method in primary cell cultures, commercial 3D primary cells, cell lines and stem-cell derived models. A variety of these models have been recently applied for pharmacological studies against severe acute respiratory syndrome-coronavirus(-2) SARS-CoV(-2), namely primary cultures with alveolar type II epithelium cells and organotypic 3D models. The herein compiled data suggest that ALI conditions must be optimized bearing in mind the type of cells (nasal, bronchial, alveolar), their origin and the objective of the study.

Stability and Activity of Interferon Beta to Treat Idiopathic Pulmonary Fibrosis with Different Nebulizer Technologies

Background: Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by lung scarring, which results in breathing difficulty. Currently, patients with IPF exhibit a poor survival rate and have access to very limited therapeutic options. Interferon beta (IFN-β) has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of relapsing forms of multiple sclerosis, and it has also been shown to exhibit therapeutic potential in IPF. However, clinical use of IFN-β did not lead to improved overall survival in IPF patients in existing studies. One possibility is the limited efficiency of IFN-β delivery through intravenous or subcutaneous injection. Materials and Methods: The aerosol particle size distribution was determined with a laser diffraction particle size analyzer to characterize the droplet size and fine particle fraction generated by three types of nebulizers: jet, ultrasonic, and mesh. A breathing simulator was used to assess the delivery efficiency of IFN-β, and the temperature in the medication reservoirs was monitored with a thermocouple during nebulization. To further evaluate the antifibrotic activity of IFN-β pre- and postnebulization, bleomycin (BLM)- or transforming growth factor-beta (TGF-β)-treated human lung fibroblast (HLF) cells were used. Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Transwell migration assay and Q-PCR analysis were used to evaluate cell migration and the myofibroblast differentiation ability, respectively. IFN-β protein samples were prepared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) sample loading buffer, and the expression of IFN-β was assessed by western blotting. Results: Among the current drug delivery systems, aerosolized medication has shown increased efficacy of drug delivery for treating respiratory diseases when compared with parenteral drugs. It was found that neither the structural integrity nor the biological function of nebulized IFN-β was compromised by the nebulization process of the mesh nebulizer. In addition, in BLM dose-response or TGF-β-induced lung fibroblast proliferation assays, these effects could be reversed by both parenteral and inhaled IFN-β nebulized with the mesh nebulizer. Nebulized IFN-β with the mesh nebulizer also significantly inhibited the migration and myofibroblast differentiation ability of TGF-β-treated HLF cells. Conclusions: The investigations revealed the potential efficacy of IFN-β in the treatment of IPF with the mesh nebulizer, demonstrating the higher efficiency of IFN-β delivered through the mesh nebulizer.

Protein Aggregates in Inhaled Biologics: Challenges and Considerations

Pulmonary delivery is the main route of administration for treatment of local lung diseases. Recently, the interest in delivery of proteins through the pulmonary route for treatment of lung diseases has significantly increased, especially after Covid-19 pandemic. The development of an inhalable protein combines the challenges of inhaled as well as biologic products since protein stability may be compromised during manufacture or delivery. For instance, spray drying is the most common technology for manufacture of inhalable biological particles, however, it imposes shear and thermal stresses which may cause protein unfolding and aggregation post drying. Therefore, protein aggregation should be evaluated for inhaled biologics as it could impact the safety and/or efficacy of the product. While there is extensive knowledge and regulatory guidance on acceptable limits of particles, which inherently include insoluble protein aggregates, in injectable proteins, there is no comparable knowledge for inhaled ones. Moreover, the poor correlation between in vitro setup for analytical testing and the in vivo lung environment limits the predictability of protein aggregation post inhalation. Thus, the purpose of this article is to highlight the major challenges facing the development of inhaled proteins compared to parenteral ones, and to share future thoughts to resolve them.