The lung as a route for systemic delivery of therapeutic proteins and peptides

Inhaled aerosolized algal polysaccharides: A novel and reliable strategy for treating pneumonia through inflammation and oxidative stress inhibition

Sepsis-associated acute lung injury (ALI) poses a significant threat, characterized by inflammation and oxidative damage. Effective drugs targeting these aspects with reliable drug delivery systems are vital for ALI management. This study aimed to evaluate the influence of algal polysaccharides (APs) with aerosolized drug delivery in ALI mice and clarify the underlying mechanism. To induce the sepsis-associated acute lung injury (ALI) model, mice were administered intraperitoneal injections of 10 mg/kg LPS for 48 h in vivo. ALI mice received APs via atomization to arrive at different sites within the lungs. Lung tissue samples and bronchoalveolar lavage fluid (BALF) were collected to access lung injury parameters. Concurrently, western blotting, H&E staining, and immunofluorescence (IF) were applied to investigate the specific impact of APs on ALI. The results showed that APs protect lung tissue against ALI by inhibiting inflammation and mitigating oxidative stress-induced damage. This study highlights promising avenues for ALI intervention using natural compounds with anti-inflammatory and antioxidant properties.

Opportunities for nanomaterials in enzyme therapy

In recent years, enzyme therapy strategies have rapidly evolved to catalyze essential biochemical reactions with therapeutic potential. These approaches hold particular promise in addressing rare genetic disorders, cancer treatment, neurodegenerative conditions, wound healing, inflammation management, and infectious disease control, among others. There are several primary reasons for the utilization of enzymes as therapeutics: their substrate specificity, their biological compatibility, and their ability to generate a high number of product molecules per enzyme unit. These features have encouraged their application in enzyme replacement therapy where the enzyme serves as the therapeutic agent to rectify abnormal metabolic and physiological processes, enzyme prodrug therapy where the enzyme initiates a clinical effect by activating prodrugs, and enzyme dynamic or starving therapy where the enzyme acts upon host substrate molecules. Currently, there are >20 commercialized products based on therapeutic enzymes, but approval rates are considerably lower than other biologicals. This has stimulated nanobiotechnology in the last years to develop nanoparticle-based solutions that integrate therapeutic enzymes. This approach aims to enhance stability, prevent rapid clearance, reduce immunogenicity, and even enable spatio-temporal activation of the therapeutic catalyst. This comprehensive review delves into emerging trends in the application of therapeutic enzymes, with a particular emphasis on the synergistic opportunities presented by incorporating enzymes into nanomaterials. Such integration holds the promise of enhancing existing therapies or even paving the way for innovative nanotherapeutic approaches.

Studies of the Crystallization and Dissolution of Individual Suspended Sodium Chloride Aerosol Particles

Aerosols transform between physical phases, as they respond to variations in environmental conditions. There are many industries that depend on these dynamic processes of crystallization and dissolution. Here, a single particle technique (an electrodynamic balance) is used to explore the crystallization and dissolution dynamics of a model system, sodium chloride. The physical and environmental factors that influence the dynamics of crystal formation from a saline droplet (whose initial radius is ∼25 μm) and the kinetics of water adsorption onto dried particles are examined. The drying relative humidity (RH) is shown to impact the physical properties of the dried particle. When a saline droplet is injected into an airflow at an RH close to the efflorescence RH (ERH, 45%), an individual single crystal forms. By contrast, when a compositionally equivalent saline droplet is injected into dry air (RH ∼ 0%), a salt crystal made of multiple crystalline particles is formed. Subsequent to crystallization, the crystal shape, morphology, and surface area were all found to affect the dissolution dynamics of the dried particle. Additionally, we report that the difference between the deliquesce RH and environmental RH significantly impacts the dissolution time scale.

Pulmonary drug delivery devices and nanosystems as potential treatment strategies for acute respiratory distress syndrome (ARDS)

Despite advances in drug delivery technologies, treating acute respiratory distress syndrome (ARDS) is challenging due to pathophysiological barriers such as lung injury, oedema fluid build-up, and lung inflammation. Active pharmaceutical ingredients (API) can be delivered directly to the lung site of action with the use of aerosol-based drug delivery devices, and this circumvents the hepatic first-pass effect and improves the bioavailability of drugs. This review discusses the various challenges and barriers for pulmonary drug delivery, current interventions for delivery, considerations for effective drug delivery, and the use of nanoparticle drug delivery carriers as potential strategies for delivering therapeutics in ARDS. Nanosystems have the added benefit of entrapping drugs, increase pulmonary drug bioavailability, and using biocompatible and biodegradable excipients that can facilitate targeted and/or controlled delivery. These systems provide an alternative to existing conventional systems. An effective way to deliver drugs for the treatment of ARDS can be by using colloidal systems that are aerosolized or inhaled. Drug distribution to the deeper pulmonary tissues is necessary due to the significant endothelial cell destruction that is prevalent in ARDS. The particle size of nanoparticles (<0.5 μm) makes them ideal candidates for treating ARDS as they can reach the alveoli. A look into the various potential benefits and limitations of nanosystems used for other lung disorders is also considered to indicate how they may be useful for the potential treatment of ARDS.

Impact of Nebulization on the Physicochemical Properties of Polymer-Lipid Hybrid Nanoparticles for Pulmonary Drug Delivery

Nanoparticles (NPs) have shown significant potential for pulmonary administration of therapeutics for the treatment of chronic lung diseases in a localized and sustained manner. Nebulization is a suitable method of NP delivery, particularly in patients whose ability to breathe is impaired due to lung diseases. However, there are limited studies evaluating the physicochemical properties of NPs after they are passed through a nebulizer. High shear stress generated during nebulization could potentially affect the surface properties of NPs, resulting in the loss of encapsulated drugs and alteration in the release kinetics. Herein, we thoroughly examined the physicochemical properties as well as the therapeutic effectiveness of Infasurf lung surfactant (IFS)-coated PLGA NPs previously developed by us after passing through a commercial Aeroneb® vibrating-mesh nebulizer. Nebulization did not alter the size, surface charge, IFS coating and bi-phasic release pattern exhibited by the NPs. However, there was a temporary reduction in the initial release of encapsulated therapeutics in the nebulized compared to non-nebulized NPs. This underscores the importance of evaluating the drug release kinetics of NPs using the inhalation method of choice to ensure suitability for the intended medical application. The cellular uptake studies demonstrated that both nebulized and non-nebulized NPs were less readily taken up by alveolar macrophages compared to lung cancer cells, confirming the IFS coating retention. Overall, nebulization did not significantly compromise the physicochemical properties as well as therapeutic efficacy of the prepared nanotherapeutics.

Lipid-Based Nanoparticles as Oral Drug Delivery Systems: Overcoming Poor Gastrointestinal Absorption and Enhancing Bioavailability of Peptide and Protein Therapeutics

Delivery and formulation of oral peptide and protein therapeutics have always been a challenge for the pharmaceutical industry. The oral bioavailability of peptide and protein therapeutics mainly relies on their gastrointestinal solubility and permeability which are affected by their poor membrane penetration, high molecular weight and proteolytic (chemical and enzymatic) degradation resulting in limited delivery and therapeutic efficacy. The present review article highlights the challenges and limitations of oral delivery of peptide and protein therapeutics focusing on the application, potential and importance of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) as lipid-based drug delivery systems (LBDDSs) and their advantages and drawbacks. LBDDSs, due to their lipid-based matrix can encapsulate both lipophilic and hydrophilic drugs, and by reducing the first-pass effect and avoiding proteolytic degradation offer improved drug stability, dissolution rate, absorption, bioavailability and controlled drug release. Furthermore, their small size, high surface area and surface modification increase their mucosal adhesion, tissue-targeted distribution, physiological function and half-life. Properties such as simple preparation, high-scale manufacturing, biodegradability, biocompatibility, prolonged half-life, lower toxicity, lower adverse effects, lipid-based structure, higher drug encapsulation rate and various drug release profile compared to other similar carrier systems makes LBDDSs a promising drug delivery system (DDS). Nevertheless, undesired physicochemical features of peptide and protein drug development and discovery such as plasma stability, membrane permeability and circulation half-life remain a serious challenge which should be addressed in future.

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.

Preparation and characterization of lysozyme loaded liposomal dry powder inhalation using non-ionic surfactants

Delivering protein drugs through dry powder inhalation (DPI) remains a significant challenge. Liposomes offer a promising solution, providing protection for proteins from external environment and controlled release capabilities. Furthermore, the use of non-ionic surfactants plays a crucial role in protecting the activity of proteins because of how the surfactants positioning themselves at the liquid-gas interface during the spray-drying process. In this study, lysozyme-loaded liposomal DPI formulations were prepared using various non-ionic surfactants, including polysorbate 80, poloxamer 188, poloxamer 407, and sucrose stearate. Lysozyme solution and 1,2-distearoyl-sn-glycero-3-phosphatidylcholine liposomes were subjected through high-pressure homogenization to form lysozyme-loaded liposomes. Formulations of homogenized lysozyme liposomes were spray-dried and further characterized. The particle size of reconstituted liposomal lysozyme DPI was from 129.5 to 816.9 nm. The formulations showed encapsulation efficiency up to 32.5% with zeta potential value of around - 30 mV, and spherical structures were observed. The aerosol dispersion performance of the dry powder inhalers was evaluated with emitted doses reaching up to 103% and fine particle fractions up to 28.4%. Significantly higher lysozyme activity was confirmed in formulation with drug to PS 80 ratio of 1: 0.5 w/w (92.1%) compared to that of formulation containing no surfactant (59.8%). The formulation stood out as the only formulation that maintained protein activity while demonstrating good aerosol performance.

Nano-mediated strategy for targeting and treatment of non-small cell lung cancer (NSCLC)

Lung cancer is the most common type of cancer, with over 2.1 million cases diagnosed annually worldwide. It has a high incidence and mortality rate, leading to extensive research into various treatment options, including the use of nanomaterial-based carriers for drug delivery. With regard to cancer treatment, the distinct biological and physico-chemical features of nano-structures have acquired considerable impetus as drug delivery system (DDS) for delivering medication combinations or combining diagnostics and targeted therapy. This review focuses on the use of nanomedicine-based drug delivery systems in the treatment of lung cancer, including the use of lipid, polymer, and carbon-based nanomaterials for traditional therapies such as chemotherapy, radiotherapy, and phototherapy. The review also discusses the potential of stimuli-responsive nanomaterials for drug delivery in lung cancer, and the limitations and opportunities for improving the design of nano-based materials for the treatment of non-small cell lung cancer (NSCLC).

RNAi therapies: Expanding applications for extrahepatic diseases and overcoming delivery challenges

The era of RNA medicine has become a reality with the success of messenger RNA (mRNA) vaccines against COVID-19 and the approval of several RNA interference (RNAi) agents in recent years. Particularly, therapeutics based on RNAi offer the promise of targeting intractable and previously undruggable disease genes. Recent advances have focused in developing delivery systems to enhance the poor cellular uptake and insufficient pharmacokinetic properties of RNAi therapeutics and thereby improve its efficacy and safety. However, such approach has been mainly achieved via lipid nanoparticles (LNPs) or chemical conjugation with N-Acetylgalactosamine (GalNAc), thus current RNAi therapy has been limited to liver diseases, most likely to encounter liver-targeting limitations. Hence, there is a huge unmet medical need for intense evolution of RNAi therapeutics delivery systems to target extrahepatic tissues and ultimately extend their indications for treating various intractable diseases. In this review, challenges of delivering RNAi therapeutics to tumors and major organs are discussed, as well as their transition to clinical trials. This review also highlights innovative and promising preclinical RNAi-based delivery platforms for the treatment of extrahepatic diseases.

Inhalable Excipient-Free Dry Powder of Tigecycline for the Treatment of Pulmonary Infections

Tigecycline (TIG) is a broad-spectrum antibiotic that has been approved for the treatment of a number of complicated infections, including community-acquired bacterial pneumonia. Currently it is available only as an intravenous injection that undergoes rapid chemical degradation and limits the use to in-patient scenarios. The use of TIG as an inhaled dry powder inhaler may offer a promising treatment option for patients with multidrug-resistant respiratory tract infections, such as Stenotrophomonas maltophilia (S. maltophilia). This study explores the feasibility of engineering an inhaled powder formulation of TIG that could administer relevant doses at a wide range of inhalation flow rates while maintaining stability of this labile drug. Using air-jet milling, micronized TIG had excellent aerosolization efficiency, with over 80% of the device emitted dose being within the respirable range. TIG was also readily dispersed using different inhaler devices even when tested at different pressure drops and flow rates. Additionally, micronized TIG was stable for 6 months at 25 °C/60% RH and 40 °C/75% RH. Micronized TIG maintained a low minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of 0.8 μM and >0.5 μM, respectively in S. maltophilia cultures in vitro. These results strongly suggest that the micronization of TIG results in a stable and respirable formulation that can be delivered via the pulmonary route for the treatment of lung infections.

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.

Cichoric acid aerosol for inhalation therapy in respiratory syncytial virus

Cichoric acid (CA) is a caffeic acid derivative, which has significant anti respiratory syncytial virus (RSV) effect and low toxicity. However, due to the low oral bioavailability and poor intestinal absorption of CA, it is not suitable to be made into oral preparations. In this study, CA was made into metered dose inhaler (MDI), allowing the drug to target the site of action, thus achieving more effective treatment. Through preliminary experiments, the drug content and prescription composition of the preparation were determined. Clarity and stability of solution were used as indexes to screen the composition of latent solvent. Single factor and orthogonal test were used to optimize the amount of latent solvent in CA-MDI, and the optimal prescription was verified. The aerosol prepared according to the optimal formula was characterized and preliminary stability was studied. The final formula of CA-MDI was: CA 15 mg, absolute ethanol 1 g, propylene glycol 0.4 g and 1,1,1,2-tetrafluoroethane 10 g. CA-MDI was prepared with the best prescription, with the specification of 150 actuation per bottle and 75 μg per actuation. After quality inspection, three batches of inhaled aerosols showed that the main drug content per bottle was 77.91 ± 1.63 μg (n = 3), and the total number of bottles was 185 ± 3 (n = 3), all of which met the standards of China Pharmacopoeia and the proposed specifications. The preliminary stability study showed that the quality of inhaled aerosols in CA was stable and reliable.

Shaping the future from the small scale: dry powder inhalation of CRISPR-Cas9 lipid nanoparticles for the treatment of lung diseases

INTRODUCTION

Most lung diseases are serious conditions resulting from genetic and environmental causes associated with high mortality and severe symptoms. Currently, treatments available have a palliative effect and many targets are still considered undruggable. Gene therapy stands as an attractive approach to offering innovative therapeutic solutions. CRISPRCas9 has established a remarkable potential for genome editing with high selectivity to targeted mutations. To ensure high efficacy with minimum systemic exposure, the delivery and administration route are key components that must be investigated.

AREAS COVERED

This review is focused on the delivery of CRISPRCas9 to the lungs, taking advantage of lipid nanoparticles (LNPs), the most clinically advanced nucleic acid carriers. We also aim to highlight the benefits of pulmonary administration as a local delivery route and the use of spray drying to prepare stable nucleic-acid-based dry powder formulations that can overcome multiple lung barriers.

EXPERT OPINION

Exploring the pulmonary administration to deliver CRISPRCas9 loaded in LNPs as a dry powder increases the chances to achieve high efficacy and reduced adverse effects. CRISPRCas9 loaded in LNP-embedded microparticles has not yet been reported in the literature but has the potential to reach and accumulate in target cells in the lung, thus, enhancing overall efficacy and safety.

Recent advances in respiratory immunization: A focus on COVID-19 vaccines

The development of vaccines has always been an essential task worldwide since vaccines are regarded as powerful weapons in protecting the global population. Although the vast majority of currently authorized human vaccinations are administered intramuscularly or subcutaneously, exploring novel routes of immunization has been a prominent area of study in recent years. This is particularly relevant in the face of pandemic diseases, such as COVID-19, where respiratory immunization offers distinct advantages, such as inducing systemic and mucosal responses to prevent viral infections in both the upper and lower respiratory tracts and also leading to higher patient compliance. However, the development of respiratory vaccines confronts challenges due to the physiological barriers of the respiratory tract, with most of these vaccines still in the research and development stage. In this review, we detail the structure of the respiratory tract and the mechanisms of mucosal immunity, as well as the obstacles to respiratory vaccination. We also examine the considerations necessary in constructing a COVID-19 respiratory vaccine, including the dosage form of the vaccines, potential excipients and mucosal adjuvants, and delivery systems and devices for respiratory vaccines. Finally, we present a comprehensive overview of the COVID-19 respiratory vaccines currently under clinical investigation. We hope this review can provide valuable insights and inspiration for the future development of respiratory vaccinations.

Identification of Three Campylobacter Lysins and Enhancement of Their Anti-Escherichia coli Efficacy Using Colicin-Based Translocation and Receptor-Binding Domain Fusion

The emergence of multidrug-resistant Escherichia coli, which poses a major threat to public health, has motivated the development of numerous alternative antimicrobials. Lysins are bacteriophage- and bacterium-derived peptidoglycan hydrolases that represent a new antibiotic treatment targeting bacterial cell walls. However, the bactericidal effect of native lysins on Gram-negative bacteria is restricted by the presence of an outer membrane. Here, we first evaluated the antibacterial activity of three Campylobacter-derived lysins (Clysins) against E. coli. To improve their transmembrane ability and antibacterial activities, six engineered Clysins were constructed by fusing with the translocation and receptor-binding (TRB) domains from two types of colicins (colicin A [TRBA] and colicin K [TRBK]), and their biological activities were determined. Notably, engineered lysin TRBK-Cly02 exhibited the highest bactericidal activity against the E. coli BL21 strain, with a reduction of 6.22 ± 0.34 log units of cells at a concentration of 60.1 μg/mL, and formed an observable inhibition zone even at a dose of 6.01 μg. Moreover, TRBK-Cly02 killed E. coli dose dependently and exhibited the strongest bactericidal activity at pH 6. It also exhibited potential bioactivity against multidrug-resistant E. coli clinical isolates. In summary, this study identified three lysins from Campylobacter strains against E. coli, and the enhancement of their antibacterial activities by TRB domains fusion may allow them to be developed as potential alternatives to antibiotics. IMPORTANCE Three lysins from Campylobacter, namely, Clysins, were investigated, and their antibacterial activities against E. coli were determined for the first time. To overcome the restriction of the outer membrane of Gram-negative bacteria, we combined the TRB domains of colicins with these Clysins. Moreover, we discovered that the Clysins fused with TRB domains from colicin K (TRBK) killed E. coli more effectively, and this provides a new foundation for the development of novel bioengineered lysins by employing TRBK constructs that target outer membrane receptor/transport systems. One of the designed lysins, TRBK-Cly02, exhibited potent bactericidal efficacy against E. coli strains and may be used for control of multidrug-resistant clinical isolates. The results suggest that TRBK-Cly02 can be considered a potential antibacterial agent against pathogenic E. coli.

The Promising Therapeutic Potential of Oligonucleotides for Pulmonary Fibrotic Diseases

INTRODUCTION

Fibrotic lung diseases represent a large subset of diseases with an unmet clinical need. Oligonucleotide therapies (ONT) are a promising therapeutic approach for the treatment of pulmonary disease as they can inhibit pathways that are otherwise difficult to target. Additionally, targeting the lung specifically with ONT is advantageous because it reduces the possibilities of systemic side effects and tolerability concerns.

AREAS COVERED

This review presents the chemical basis of designing various ONTs currently known to treat fibrotic lung diseases. Further, the authors have also discussed the delivery vehicle, routes of administration, physiological barriers of the lung, and toxicity concerns with ONTs.

EXPERT OPINION

ONTs provide a promising therapeutic approach for the treatment of fibrotic diseases of the lung, particularly because ONTs directly delivered to the lung show little systemic side effects compared to current therapeutic strategies. Dry powder aerosolized inhalers may be a good strategy for getting ONTs into the lung in humans. However, as of now, no dry powder ONTs have been approved for use in the clinical setting, and this challenge must be overcome for future therapies. Various delivery methods that can aid in direct targeting may also improve the use of ONTs for lung fibrotic diseases.

Nanotechnology as a tool to overcome macromolecules delivery issues

Nanocarriers can deliver drugs to specific organs or cells, potentially bridging the gap between a drug's function and its interaction with biological systems such as human physiology. The untapped potential of nanotechnology stems from its ability to manipulate materials, allowing control over physical and chemical properties and overcoming drug-related problems, e.g., poor solubility or poor bioavailability. For example, most protein drugs are administered parenterally, each with challenges and peculiarities. Some problems faced by bioengineered macromolecule drugs leading to poor bioavailability are short biological half-life, large size and high molecular weight, low permeability through biological membranes, and structural instability. Nanotechnology emerges as a promising strategy to overcome these problems. Nevertheless, the delivery system should be carefully chosen considering loading efficiency, physicochemical properties, production conditions, toxicity, and regulations. Moving from the bench to the bedside is still one of the major bottlenecks in nanomedicine, and toxicological issues are the greatest challenges to overcome. This review provides an overview of biotech drug delivery approaches, associated nanotechnology novelty, toxicological issues, and regulations.

Bacteriophage-encoded lethal membrane disruptors: Advances in understanding and potential applications

Holins and spanins are bacteriophage-encoded membrane proteins that control bacterial cell lysis in the final stage of the bacteriophage reproductive cycle. Due to their efficient mechanisms for lethal membrane disruption, these proteins are gaining interest in many fields, including the medical, food, biotechnological, and pharmaceutical fields. However, investigating these lethal proteins is challenging due to their toxicity in bacterial expression systems and the resultant low protein yields have hindered their analysis compared to other cell lytic proteins. Therefore, the structural and dynamic properties of holins and spanins in their native environment are not well-understood. In this article we describe recent advances in the classification, purification, and analysis of holin and spanin proteins, which are beginning to overcome the technical barriers to understanding these lethal membrane disrupting proteins, and through this, unlock many potential biotechnological applications.

Factors Affecting Drug Exposure after Inhalation

Administration of drugs by inhalation is mainly used to treat lung diseases and is being investigated as a possible route for systemic drug delivery. It offers several benefits, but it is also fraught with many difficulties. The lung is a complex organ with complicated physiology and specific pharmacokinetic processes. Therefore, the exposure and subsequently efficacy of a drug after inhalation is affected by a number of factors. In this review, we summarize the main variables that may affect drug fate after inhalation delivery, such as physicochemical properties of the drug, pulmonary clearance and metabolism, pathophysiological factors and inhalation device. Factors that have impact on pharmacokinetic processes need to be considered during development as their correct setting can lead to new effective inhaled drugs.

Progress in non-viral localized delivery of siRNA therapeutics for pulmonary diseases

Emerging therapies based on localized delivery of siRNA to lungs have opened up exciting possibilities for treatment of different lung diseases. Localized delivery of siRNA to lungs has shown to result in severalfold higher lung accumulation than systemic route, while minimizing non-specific distribution in other organs. However, to date, only 2 clinical trials have explored localized delivery of siRNA for pulmonary diseases. Here we systematically reviewed recent advances in the field of pulmonary delivery of siRNA using non-viral approaches. We firstly introduce the routes of local administration and analyze the anatomical and physiological barriers towards effective local delivery of siRNA in lungs. We then discuss current progress in pulmonary delivery of siRNA for respiratory tract infections, chronic obstructive pulmonary diseases, acute lung injury, and lung cancer, list outstanding questions, and highlight directions for future research. We expect this review to provide a comprehensive understanding of current advances in pulmonary delivery of siRNA.

Advances in the design of new types of inhaled medicines

Inhalation of small molecule drugs has proven very efficacious for the treatment of respiratory diseases due to enhanced efficacy and a favourable therapeutic index compared with other dosing routes. It enables targeted delivery to the lung with rapid onset of therapeutic action, low systemic drug exposure, and thereby reduced systemic side effects. An increasing number of pharmaceutical companies and biotechs are investing in new modalities-for this review defined as therapeutic molecules with a molecular weight >800Da and therefore beyond usual inhaled small molecule drug-like space. However, our experience with inhaled administration of PROTACs, peptides, oligonucleotides (antisense oligonucleotides, siRNAs, miRs and antagomirs), diverse protein scaffolds, antibodies and antibody fragments is still limited. Investigating the retention and metabolism of these types of molecules in lung tissue and fluid will contribute to understanding which are best suited for inhalation. Nonetheless, the first such therapeutic molecules have already reached the clinic. This review will provide information on the physiology of healthy and diseased lungs and their capacity for drug metabolism. It will outline the stability, aggregation and immunogenicity aspects of new modalities, as well as recap on formulation and delivery aspects. It concludes by summarising clinical trial outcomes with inhaled new modalities based on information available at the end of 2021.

Biomedical applications of polysaccharide nanoparticles for chronic inflammatory disorders: Focus on rheumatoid arthritis, diabetes and organ fibrosis

Polysaccharides are biopolymers distinguished by their complex secondary structures executing various roles in microorganisms, plants, and animals. They are made up of long monomers of similar type or as a combination of other monomeric chains. Polysaccharides are considered superior as compared to other polymers due to their diversity in charge and size, biodegradability, abundance, bio-compatibility, and less toxicity. These natural polymers are widely used in designing of nanoparticles (NPs) which possess wide applications in therapeutics, diagnostics, delivery and protection of bioactive compounds or drugs. The side chain reactive groups of polysaccharides are advantageous for functionalization with nanoparticle-based conjugates or therapeutic agents such as small molecules, proteins, peptides and nucleic acids. Polysaccharide NPs show excellent pharmacokinetic and drug delivery properties, facilitate improved oral absorption, control the release of drugs, increases in vivo retention capability, targeted delivery, and exert synergistic effects. This review updates the usage of polysaccharides based NPs particularly cellulose, chitosan, hyaluronic acid, alginate, dextran, starch, cyclodextrins, pullulan, and their combinations with promising applications in diabetes, organ fibrosis and arthritis.

A roadmap to pulmonary delivery strategies for the treatment of infectious lung diseases

Pulmonary drug delivery is a highly attractive topic for the treatment of infectious lung diseases. Drug delivery via the pulmonary route offers unique advantages of no first-pass effect and high bioavailability, which provides an important means to deliver therapeutics directly to lung lesions. Starting from the structural characteristics of the lungs and the biological barriers for achieving efficient delivery, we aim to review literatures in the past decade regarding the pulmonary delivery strategies used to treat infectious lung diseases. Hopefully, this review article offers new insights into the future development of therapeutic strategies against pulmonary infectious diseases from a delivery point of view.

State-of-the-Art Review of The Application and Development of Various Methods of Aerosol Therapy

Aerosol therapy is a rapidly developing field of science. Due to a number of advantages, the administration of drugs to the body with the use of aerosol therapy is becoming more and more popular. Spraying drugs into the patient's lungs has a significant advantage over other methods of administering drugs to the body, including injection and oral methods. In order to conduct proper and effective aerosol therapy, it is necessary to become familiar with the basic principles and applications of aerosol therapy under various conditions. The effectiveness of inhalation depends on many factors, but most of all on: the physicochemical properties of the sprayed system, the design of the medical inhaler and its correct application, the dynamics of inhalation (i.e. the frequency of breathing and the volume of inhaled air). It is worth emphasizing that respiratory system diseases are one of the most frequently occurring and fastest growing diseases in the world. Accordingly, in recent years, a significant increase in the number of new spraying devices and pharmaceutical drugs for spraying has appeared on the market. It should also be remembered that the process of spraying a liquid is a complicated and complex process, and its efficiency is very often characterized by the use of micro- and macro parameters (including average droplet diameters or the spectrum of droplet diameter distribution). In order to determine the effectiveness of the atomization process and in the delivery of drugs to the patient's respiratory tract, the analysis of the size of the generated aerosol droplets is most often performed. Based on the proposed literature review, it has been shown that many papers dealt with the issues related to aerosol therapy, the selection of an appropriate spraying device, the possibility of modifying the spraying devices in order to increase the effectiveness of inhalation, and the possibility of occurrence of certain discrepancies resulting from the use of various measurement methods to determine the characteristics of the generated aerosol. The literature review presented in the paper was prepared in order to better understand the spraying process. Moreover, it can be helpful in choosing the right medical inhaler for a given liquid with specific rheological properties. The experimental data contained in this study are of great cognitive importance and may be of interest to entities involved in pharmaceutical product engineering (in particular in the case of the production of drugs containing liquids with complex rheological properties).

Treating Bacterial Infections with Bacteriophage-Based Enzybiotics: In Vitro, In Vivo and Clinical Application

Over the past few decades, we have witnessed a surge around the world in the emergence of antibiotic-resistant bacteria. This global health threat arose mainly due to the overuse and misuse of antibiotics as well as a relative lack of new drug classes in development pipelines. Innovative antibacterial therapeutics and strategies are, therefore, in grave need. For the last twenty years, antimicrobial enzymes encoded by bacteriophages, viruses that can lyse and kill bacteria, have gained tremendous interest. There are two classes of these phage-derived enzymes, referred to also as enzybiotics: peptidoglycan hydrolases (lysins), which degrade the bacterial peptidoglycan layer, and polysaccharide depolymerases, which target extracellular or surface polysaccharides, i.e., bacterial capsules, slime layers, biofilm matrix, or lipopolysaccharides. Their features include distinctive modes of action, high efficiency, pathogen specificity, diversity in structure and activity, low possibility of bacterial resistance development, and no observed cross-resistance with currently used antibiotics. Additionally, and unlike antibiotics, enzybiotics can target metabolically inactive persister cells. These phage-derived enzymes have been tested in various animal models to combat both Gram-positive and Gram-negative bacteria, and in recent years peptidoglycan hydrolases have entered clinical trials. Here, we review the testing and clinical use of these enzymes.

Dry powder inhaler formulation comparison: Study of the role of particle deposition pattern and dissolution

The composition, morphology and dissolution profile of particles and micro-sized agglomerates delivered upon inhalation may have a significant impact on the product clinical effect. However, although several efforts are ongoing, a methodology that considers deposition structures and dissolution performance evaluation in a biorelevant set-up is not yet standardized. The goal of this work is to apply a collection and dissolution methodology able to discriminate dry powder inhaler (DPI) formulations in terms of deposition structures and dissolution profile in vitro. Hence, Fluticasone Propionate (FP) engineered particles and formulated products (used as a case study) were collected employing a breath simulator and characterized regarding (i) aerodynamic particle size distribution; (ii) deposited microstructures; and (iii) dissolution/absorption profiles using the DissolvIt® bio-relevant dissolution equipment. The results indicated that the particle engineering technology had an impact on the generated and deposited microstructures, here associated to the differences on surface properties of jet milled and wet polished particles quantified by the specific surface area. Differences on surface properties modulate particle interactions, resulting in agglomerates of drug substance and excipient upon actuation with significant different morphologies, observed by microscope, as well as quantified by Marple cascade impactor. These observations allow for a further understanding of the DPI aerosolization and deposition mechanisms. The dissolution and absorption assessment indicates that the presence of lactose may accelerate the drug substance dissolution kinetics, and the FP dissolution can be significantly enhanced when formulated as a spray-dried dispersion particle. Ultimately, the results suggest dissolution testing can be an essential tool to both optimize an innovator DPI and de-risk generics development.

Current Status of Endolysin-Based Treatments against Gram-Negative Bacteria

The prevalence of multidrug-resistant Gram-negative bacteria is a public health concern. Bacteriophages and bacteriophage-derived lytic enzymes have been studied in response to the emergence of multidrug-resistant bacteria. The availability of tRNAs and endolysin toxicity during recombinant protein expression is circumvented by codon optimization and lower expression levels using inducible pET-type plasmids and controlled cultivation conditions, respectively. The use of polyhistidine tags facilitates endolysin purification and alters antimicrobial activity. Outer membrane permeabilizers, such as organic acids, act synergistically with endolysins, but some endolysins permeate the outer membrane of Gram-negative bacteria per se. However, the outer membrane permeation mechanisms of endolysins remain unclear. Other strategies, such as the co-administration of endolysins with polymyxins, silver nanoparticles, and liposomes confer additional outer membrane permeation. Engineered endolysins comprising domains for outer membrane permeation is also a strategy used to overcome the current challenges on the control of multidrug-resistant Gram-negative bacteria. Metagenomics is a new strategy for screening endolysins with interesting antimicrobial properties from uncultured phage genomes. Here, we review the current state of the art on the heterologous expression of endolysin, showing the potential of bacteriophage endolysins in controlling bacterial infections.

Association between anaphylaxis and anti-influenza drug use: An analysis of the Japanese Adverse Drug Event Report database

We aimed to investigate the association between anaphylaxis and anti-influenza drug use using the Japanese Adverse Drug Event Report (JADER) database, a national spontaneous reporting database in Japan. We surveyed registered cases from the JADER database between April 2004 and November 2019. The target drugs were five anti-influenza drugs, namely oseltamivir, zanamivir, peramivir, laninamivir, and baloxavir. Adverse events associated with anaphylaxis, "anaphylactic reaction," "anaphylactic shock," "anaphylactoid reaction," and "anaphylactoid shock," were evaluated. The association between anaphylaxis and anti-influenza drug use was assessed by calculating the reporting odds ratio (ROR) and information component (IC) as a measure of disproportionality. Signals were considered positive if the lower limit of the 95% confidence interval (CI) of ROR was > 1, and that of IC was > 0. The number of anaphylaxis cases associated with anti-influenza drug use was 199 (0.9%). Signals were detected for inhaled laninamivir (ROR: 4.24 [95% CI: 3.06-5.88], IC: 1.83 [1.35-2.30]), intravenous peramivir (ROR: 2.97 [2.11-4.17], IC: 1.40 [0.90-1.89]), and oral baloxavir (ROR: 3.05 [2.22-4.18], IC: 1.44 [0.98-1.90]). Conversely, signals were not detected for oral oseltamivir or inhaled zanamivir. Although zanamivir and laninamivir were used as dry powder inhalers containing lactose as an additive, they differed in terms of signal detection. Our analysis indicated that the signal of anaphylaxis may varies based on the main component or dosage form of each anti-influenza drug. Appropriate use of these drugs is essential to prevent anaphylaxis and improve health status.

Dry powder pharmaceutical biologics for inhalation therapy

Therapeutic biologics such as genes, peptides, proteins, virus and cells provide clinical benefits and are becoming increasingly important tools in respiratory medicine. Pulmonary delivery of therapeutic biologics enables the potential for safe and effective treatment option for respiratory diseases due to high bioavailability while minimizing absorption into the systemic circulation, reducing off-target toxicity to other organs. Development of inhalable powder formulation requires stabilization of complex biological materials, and each type of biologics may present unique challenges and require different formulation strategy combined with manufacture process to ensure biological and physical stabilities during production and over shelf-life. This review examines key formulation strategies for stabilizing proteins, nucleic acids, virus (bacteriophages) and bacterial cells in inhalable powders. It also covers characterization methods used to assess physicochemical properties and aerosol performance of the powders, biological activity and structural integrity of the biologics, and chemical analysis at the nanoscale. Furthermore, the review includes manufacture technologies which are based on lyophilization and spray-drying as they have been applied to manufacture Food and Drug Administration (FDA)-approved protein powders. In perspective, formulation and manufacture of inhalable powders for biologic are highly challenging but attainable. The key requirements are the stability of both the biologics and the powder, along with the powder dispersibility. The formulation to be developed depends on the manufacture process as it will subject the biologics to different stresses (temperature, mechanical and chemical) which could lead to degradation by different pathways. Stabilizing excipients coupled with the suitable choice of process can alleviate the stability issues of inhaled powders of biologics.

Novel formulations and drug delivery systems to administer biological solids

Recent advances in formulation sciences have expanded the previously limited design space for biological modalities, including peptide, protein, and vaccine products. At the same time, the discovery and application of new modalities, such as cellular therapies and gene therapies, have presented formidable challenges to formulation scientists. We explore these challenges and highlight the opportunities to overcome them through the development of novel formulations and drug delivery systems as biological solids. We review the current progress in both industry and academic laboratories, and we provide expert perspectives in those settings. Formulation scientists have made a tremendous effort to accommodate the needs of these novel delivery routes. These include stability-preserving formulations and dehydration processes as well as dosing regimes and dosage forms that improve patient compliance.

The Advantages and Challenges of Using Endolysins in a Clinical Setting

Antibiotic-resistant pathogens are increasingly more prevalent and problematic. Traditional antibiotics are no longer a viable option for dealing with these multidrug-resistant microbes and so new approaches are needed. Bacteriophage-derived proteins such as endolysins could offer one effective solution. Endolysins are bacteriophage-encoded peptidoglycan hydrolases that act to lyse bacterial cells by targeting their cell’s wall, particularly in Gram-positive bacteria due to their naturally exposed peptidoglycan layer. These lytic enzymes have received much interest from the scientific community in recent years for their specificity, mode of action, potential for engineering, and lack of resistance mechanisms. Over the past decade, a renewed interest in endolysin therapy has led to a number of successful applications. Recombinant endolysins have been shown to be effective against prominent pathogens such as MRSA, Listeria monocytogenes, Staphylococcus strains in biofilm formation, and Pseudomonas aeruginosa. Endolysins have also been studied in combination with other antimicrobials, giving a synergistic effect. Although endolysin therapy comes with some regulatory and logistical hurdles, the future looks promising, with the emergence of engineered “next-generation” lysins. This review will focus on the likelihood that endolysins will become a viable new antimicrobial therapy and the challenges that may have to be overcome along the way.

Hot melt extrusion: An emerging manufacturing method for slow and sustained protein delivery

With the rapid development of the biopharmaceutical industry, an increasing number of new therapeutic protein products (TPPs) have been approved by the FDA and many others are under pre-clinical and clinical evaluation. A major limitation of biopharmaceuticals is their limited half-life when administered systemically. A one-time, implantable, sustained protein delivery device would be advantageous in order to improve the quality of life of patients. Hot melt extrusion (HME) is a mature technology that has been extensively used for a broad spectrum of applications in the polymer and pharmaceutical industry and has achieved success as evidenced by a variety of FDA-approved commercial products. These commercial products are mostly for sustained delivery of small molecule therapeutics, leaving a significant gap for HME formulation of therapeutic proteins. With the increasing need of sustained TPP delivery, HME shows promise as a downstream processing method due to its high efficiency and economic value. Several challenges remain for the application of HME in protein delivery. Progress of HME for protein delivery, challenges encountered, and potential solutions will be detailed in this review article. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

Aerosol Inhalation Delivery of Triazavirin in Mice: Outlooks for Advanced Therapy Against Novel Viral Infections

Under pandemic-caused emergency, evaluation of the potential of existing antiviral drugs for the treatment of COVID-19 is relevant. Triazavirin, an antiviral drug developed in Russia for per-oral administration, is involved in clinical trials against SARS-CoV-2 coronavirus. This virus has affinity to epithelial cells in respiratory tract, so drug delivery directly in lungs may enhance therapeutic effect and reduce side effects for stomach, liver, kidneys. We elaborated ultrasonic method of triazavirin aerosol generation and investigated the inhalation delivery of this drug in mice. Mean particle size and number concentration of aerosol used in inhalation experiments are 560 nm and 4 × 105 cm-3, respectively. Aerosol mass concentration is 1.6 × 10-4 mg/cm3. Inhalation for 20 min in a nose-only chamber resulted in 2 mg/kg body delivered dose and 2.6 μg/mL triazavirin concentration in blood plasma. Elimination rate constant determined in aerosol administration experiments was ke = 0.077 min-1, which agrees with the value measured after intravenous delivery, but per-oral administration resulted in considerably lower apparent elimination rate constant of pseudo-first order, probably due to non-linear dependence of absorption rate on triazavirin concentration in gastrointestinal tract. The bioavailability of triazavirin aerosol is found to be 85%, which is about four times higher than for per-oral administration.

Ethylcellulose nanoparticles prepared from nano-emulsion templates as new folate binding haemocompatible platforms

Ethylcellulose is a biocompatible polymer attracting increasing interest for biomedical applications. In the present work, the formation of folate-ethylcellulose nanoparticle complexes from nano-emulsion templates prepared by a low-energy approach, using aqueous components suitable for biomedical applications has been investigated. The composition of the aqueous component is shown to be crucial for the formation of stable nano-emulsions and influences the zeta potential values. The ethylcellulose nanoparticles with mean sizes around 100 nm were obtained from the nano-emulsions by solvent evaporation and showed positive zeta potential values above +20 mV due to the presence of the cationic surfactant. The nanoparticles were successfully complexed with folate, as evidenced by both particle size and zeta potential measurements. The complexes prepared with HEPES buffered glucose solution showed excellent haemocompatibility, which make them promising for parenteral therapeutic applications and also for those in which easy access to systemic circulation may occur, like in lungs.

Inhaled RNA Therapeutics for Obstructive Airway Diseases: Recent Advances and Future Prospects

Obstructive airway diseases, e.g., chronic obstructive pulmonary disease (COPD) and asthma, represent leading causes of morbidity and mortality worldwide. However, the efficacy of currently available inhaled therapeutics is not sufficient for arresting disease progression and decreasing mortality, hence providing an urgent need for development of novel therapeutics. Local delivery to the airways via inhalation is promising for novel drugs, because it allows for delivery directly to the target site of action and minimizes systemic drug exposure. In addition, novel drug modalities like RNA therapeutics provide entirely new opportunities for highly specific treatment of airway diseases. Here, we review state of the art of conventional inhaled drugs used for the treatment of COPD and asthma with focus on quality attributes of inhaled medicines, and we outline the therapeutic potential and safety of novel drugs. Subsequently, we present recent advances in manufacturing of thermostable solid dosage forms for pulmonary administration, important quality attributes of inhalable dry powder formulations, and obstacles for the translation of inhalable solid dosage forms to the clinic. Delivery challenges for inhaled RNA therapeutics and delivery technologies used to overcome them are also discussed. Finally, we present future prospects of novel inhaled RNA-based therapeutics for treatment of obstructive airways diseases, and highlight major knowledge gaps, which require further investigation to advance RNA-based medicine towards the bedside.

Progress in the Application of Nano- and Micro-based Drug Delivery Systems in Pulmonary Drug Delivery

Nanotechnology is associated with the development of particles in the nano-size range that can be used in a wide range of applications in the medical field. It has gained more importance in the pharmaceutical research field particularly in drug delivery, as it results in enhanced therapeutic drug performance, improved drug solubility, targeted drug delivery to the specific sites, minimized side effects, and prolonged drug retention time in the targeted site. To date, the application of nanotechnology continues to offer several benefits in the treatment of various chronic diseases and results in remarkable improvements in treatment outcomes. The use of nano-based delivery systems such as liposomes, micelles, and nanoparticles in pulmonary drug delivery have shown to be a promising strategy in achieving drug deposition and maintained controlled drug release in the lungs. They have been widely used to minimize the risks of drug toxicity in vivo. In this review, recent advances in the application of nano- and micro-based delivery systems in pulmonary drug delivery for the treatment of various pulmonary diseases, such as lung cancer, asthma, and chronic obstructive pulmonary disease, are highlighted. Limitations in the application of these drug delivery systems and some key strategies in improving their formulation properties to overcome challenges encountered in drug delivery are also discussed.

Nano targeted Therapies Made of Lipids and Polymers have Promising Strategy for the Treatment of Lung Cancer

The introduction of nanoparticles made of polymers, protein, and lipids as drug delivery systems has led to significant progress in modern medicine. Since the application of nanoparticles in medicine involves the use of biodegradable, nanosized materials to deliver a certain amount of chemotherapeutic agents into a tumor site, this leads to the accumulation of these nanoencapsulated agents in the right region. This strategy minimizes the stress and toxicity generated by chemotherapeutic agents on healthy cells. Therefore, encapsulating chemotherapeutic agents have less cytotoxicity than non-encapsulation ones. The purpose of this review is to address how nanoparticles made of polymers and lipids can successfully be delivered into lung cancer tumors. Lung cancer types and their anatomies are first introduced to provide an overview of the general lung cancer structure. Then, the rationale and strategy applied for the use of nanoparticle biotechnology in cancer therapies are discussed, focusing on pulmonary drug delivery systems made from liposomes, lipid nanoparticles, and polymeric nanoparticles. Many nanoparticles fabricated in the shape of liposomes, lipid nanoparticles, and polymeric nanoparticles are summarized in our review, with a focus on the encapsulated chemotherapeutic molecules, ligand-receptor attachments, and their targets. Afterwards, we highlight the nanoparticles that have demonstrated promising results and have been delivered into clinical trials. Recent clinical trials that were done for successful nanoparticles are summarized in our review.

Inhalation of sustained release microparticles for the targeted treatment of respiratory diseases

Delivering drugs through inhalation for systemic and local applications has been in practice since several decades to treat various diseases. In recent times, inhalation drug delivery is becoming one of the highly focused areas of research in the pharmaceutical industry. It is being considered as one of the major portals for delivering drugs because of its wide range of advantages like requirement of low concentrations of drug to reach therapeutic efficacy, surpassing first pass metabolism and a very low incidence of side effects as compared to conventional delivery of drugs. Owing to these favorable characteristics of pulmonary drug delivery, diverse pharmaceutical formulations like liposomes, nanoparticles, and microparticles are developed through consistent efforts for delivery drugs to lungs in suitable form. However, drug-loaded microparticles have displayed various advantages over the other pharmaceutical dosage forms which give a cutting edge over other inhalational drug delivery systems. Assuring results with respect to sustained release through inhalational delivery of drug-loaded microparticles from pre-clinical studies are anticipative of similar benefits in the clinical settings. This review centralizes partly on the advantages of inhalational microparticles over other inhalational dosage forms and largely on the therapeutic applications and future perspectives of inhalable microparticle drug delivery systems.

An Overview on Spray-Drying of Protein-Loaded Polymeric Nanoparticles for Dry Powder Inhalation

The delivery of therapeutic proteins remains a challenge, despite recent technological advances. While the delivery of proteins to the lungs is the gold standard for topical and systemic therapy through the lungs, the issue still exists. While pulmonary delivery is highly attractive due to its non-invasive nature, large surface area, possibility of topical and systemic administration, and rapid absorption circumventing the first-pass effect, the absorption of therapeutic proteins is still ineffective, largely due to the immunological and physicochemical barriers of the lungs. Most studies using spray-drying for the nanoencapsulation of drugs focus on the delivery of conventional drugs, which are less susceptible to bioactivity loss, compared to proteins. Herein, the development of polymeric nanoparticles by spray-drying for the delivery of therapeutic proteins is reviewed with an emphasis on its advantages and challenges, and the techniques to evaluate their in vitro and in vivo performance. The protein stability within the carrier and the features of the carrier are properly addressed.

Pulmonary Delivery of Biological Drugs

In the last decade, biological drugs have rapidly proliferated and have now become an important therapeutic modality. This is because of their high potency, high specificity and desirable safety profile. The majority of biological drugs are peptide- and protein-based therapeutics with poor oral bioavailability. They are normally administered by parenteral injection (with a very few exceptions). Pulmonary delivery is an attractive non-invasive alternative route of administration for local and systemic delivery of biologics with immense potential to treat various diseases, including diabetes, cystic fibrosis, respiratory viral infection and asthma, etc. The massive surface area and extensive vascularisation in the lungs enable rapid absorption and fast onset of action. Despite the benefits of pulmonary delivery, development of inhalable biological drug is a challenging task. There are various anatomical, physiological and immunological barriers that affect the therapeutic efficacy of inhaled formulations. This review assesses the characteristics of biological drugs and the barriers to pulmonary drug delivery. The main challenges in the formulation and inhalation devices are discussed, together with the possible strategies that can be applied to address these challenges. Current clinical developments in inhaled biological drugs for both local and systemic applications are also discussed to provide an insight for further research.

Structured micro/nano materials synthesized via electrospray: a review

The development of synthetic methods for micro/nano materials with precisely controlled structures, morphologies, and local compositions is of great importance for the advancement of modern nanotechnology. The electrospray method is a "platform" approach for the preparation of a broad range of micro-/nanostructures; electrospray is simple and scalable. This review summarizes recent research on the micro-/nanostructures prepared via the electrospray route. These include spherical structures (e.g. simple, porous, Janus, and core-shell particles), non-spherical structures (e.g. red blood cell-like and spindle-like particles, multi-compartment microrods, 2D holey nanosheets, and nanopyramids), and assembled structures. The experimental details, underlying physical/chemical principles, and key benefits of these structures are comprehensively discussed. The effects and importance of nozzle design, properties of feeding solutions (e.g. concentration of solute, polymer additives, solvent/nonsolvent combinations), working environment (e.g. temperature and humidity), and types of collection media are highlighted.

Model-Informed Drug Discovery and Development in Pulmonary Delivery: Biopharmaceutical Pharmacometric Modeling for Formulation Evaluation of Pulmonary Suspensions

For respiratory conditions, targeted drug delivery to the lungs could produce higher local concentrations with reduced risk of adverse events compared to systemic administration. Despite the increasing interest in pulmonary delivery, the pharmacokinetics (PK) of drugs following pulmonary administration remains to be elucidated. In this context, the application of modeling and simulation methodologies to characterize PK properties of compounds following pulmonary administration remains a scarcity. Pseudomonas aeruginosa (PA) lung infections are resistant to many of the current antibiotic therapies. Targeted treatments for pulmonary delivery could be particularly beneficial for these local conditions. In this study, we report the application of biopharmaceutical pharmacometrics (BPMX) for the analysis of PK data from three investigational antimicrobial agents following pulmonary administration of a suspension formulation. The observed drug concentration-time profiles in lungs and plasma of the compound series were combined for simultaneous analysis and modeling. The developed model describes the PK data, taking into account formulation properties, and provides a mechanism to predict dissolved drug concentrations in the lungs available for activity. The model was then used to evaluate formulation effects and the impact of variability on total and dissolved drug concentrations in lungs and plasma. The predictions suggest that these therapies for lung delivery should ideally be delivered in a sustained release formulation with high solubility for maximum local exposure in lungs for efficacy, with rapid systemic clearance in plasma for reduced risk of unwanted systemic adverse effects. This work shows the potential benefits of BPMX and the role it can play to support drug discovery and development in pulmonary delivery.