Inhalation Delivery for the Treatment and Prevention of COVID-19 Infection

Ethanol Inhalation for Respiratory Infections due to Enveloped Viruses

Ethanol has demonstrated high efficacy in inactivating enveloped viruses in vitro and in vivo (in animal and human studies). The inhalation route has been a significant method of drug administration for respiratory disorders since ancient times. Infections with enveloped viruses cause many respiratory diseases. This concise review explores the general structural characteristics of enveloped viruses and examines the potential role of inhaled ethanol as a low-cost therapy for respiratory diseases. Current literature data suggest that ethanol inhalation could be beneficial in treating respiratory infections caused by enveloped viruses. However, there is a clear gap in well-designed clinical trials assessing the safety and efficacy of ethanol inhalation in treating respiratory infections from enveloped viruses. This low-cost therapy could become an important therapeutic option, especially for large numbers of patients simultaneously infected, as was the case during the coronavirus disease 2019 (COVID-19) pandemic. In addition, inhaled ethanol could be a successful approach for vulnerable patients such as patients with cancer because it is likely to have no or minimal effects on already established life-saving treatments. Further investigation by national and international institutions is urgently needed to validate these findings and refine treatment protocols.

Exosome-Based Vaccines: Pioneering New Frontiers in Combating Infectious Diseases and Cancer

Exosomes, small extracellular vesicles with lipid bilayer membranes, play a crucial role in cellular communication and can transfer diverse biological cargo, including proteins, lipids, and nucleic acids, from donor to recipient cells. Exosomes possess diverse immunological properties, such as antigen delivery and immune activation, along with excellent drug delivery capabilities, making them promising candidates for vaccine development. For different diseases, exosome-based vaccines can be designed as therapeutic or prophylactic vaccines by leveraging cellular immunity or humoral immunity. With the emergence of precision medicine, exosome-based personalized vaccines demonstrate exceptional therapeutic potential. This review systematically introduces the sources, biogenesis mechanisms, and components of exosomes and describes their regulatory roles in the immune system. Subsequently, the preparation, administration, and personalized therapy of exosome-based vaccines are discussed. Finally, the applications and clinical trials of exosome-based vaccines in the fields of anti-infection and anti-tumor therapies are particularly highlighted, with an analysis of the potential challenges in future vaccine development.

Inhaled Dry Powder of Antiviral Agents: A Promising Approach to Treating Respiratory Viral Pathogens

Inhaled dry powder formulations of antiviral agents represent a novel and potentially transformative approach to managing respiratory viral infections. Traditional antiviral therapies in the form of tablets or capsules often face limitations in terms of therapeutic activity, systemic side effects, and delayed onset of action. Dry powder inhalers (DPIs) provide a targeted delivery system, ensuring the direct administration of antivirals to the infection site, the respiratory tract, which potentially enhance therapeutic efficacy and minimize systemic exposure. This review explores the current state of inhaled dry powder antiviral agents, their advantages over traditional routes, and specific formulations under development. We discuss the benefits of targeted delivery, such as improved drug deposition in the lungs and reduced side effects, alongside considerations related to the formulation preparation. In addition, we summarize the developed (published and marketed) inhaled dry powders of antiviral agents.

ACE2 Receptor-Targeted Inhaled Nanoemulsions Inhibit SARS-CoV-2 and Attenuate Inflammatory Responses

Three kinds of coronaviruses are highly pathogenic to humans, and two of them mainly infect humans through Angiotensin-converting enzyme 2 （ACE2）receptors. Therefore, specifically blocking ACE2 binding at the interface with the receptor-binding domain is promising to achieve both preventive and therapeutic effects of coronaviruses. Alternatively, drug-targeted delivery based on ACE2 receptors can further improve the efficacy and safety of inhalation drugs. Here, these two approaches are innovatively combined by designing a nanoemulsion (NE) drug delivery system (termed NE-AYQ) for inhalation that targets binding to ACE2 receptors. This inhalation-delivered remdesivir nanoemulsion (termed RDSV-NE-AYQ) effectively inhibits the infection of target cells by both wild-type and mutant viruses. The RDSV-NE-AYQ strongly inhibits Severe acute respiratory syndrome coronavirus 2 at two dimensions: they not only block the binding of the virus to host cells at the cell surface but also restrict virus replication intracellularly. Furthermore, in the mouse model of acute lung injury, the inhaled drug delivery system loaded with anti-inflammatory drugs (TPCA-1-NE-AYQ) can significantly alleviate the lung tissue injury of mice. This smart combination provides a new choice for dealing with possible emergencies in the future and for the rapid development of inhaled drugs for the treatment of respiratory diseases.

Liposomal drug delivery to the lungs: a post covid-19 scenario

High local delivery of anti-infectives to the lungs is required for activity against infections of the lungs. The present pandemic has highlighted the potential of pulmonary delivery of anti-infective agents as a viable option for infections like Covid-19, which specifically causes lung infections and mortality. To prevent infections of such type and scale in the future, target-specific delivery of drugs to the pulmonary region is a high-priority area in the field of drug delivery. The suboptimal effect of oral delivery of anti-infective drugs to the lungs due to the poor biopharmaceutical property of the drugs makes this delivery route very promising for respiratory infections. Liposomes have been used as an effective delivery system for drugs due to their biocompatible and biodegradable nature, which can be used effectively for target-specific drug delivery to the lungs. In the present review, we focus on the use of liposomal drug delivery of anti-infectives for the acute management of respiratory infections in the wake of Covid-19 infection.

Engineering Inhalable Therapeutic Particles: Conventional and Emerging Approaches

Respirable particles are integral to effective inhalable therapeutic ingredient delivery, demanding precise engineering for optimal lung deposition and therapeutic efficacy. This review describes different physicochemical properties and their role in determining the aerodynamic performance and therapeutic efficacy of dry powder formulations. Furthermore, advances in top-down and bottom-up techniques in particle preparation, highlighting their roles in tailoring particle properties and optimizing therapeutic outcomes, are also presented. Practices adopted for particle engineering during the past 100 years indicate a significant transition in research and commercial interest in the strategies used, with several innovative concepts coming into play in the past decade. Accordingly, this article highlights futuristic particle engineering approaches such as electrospraying, inkjet printing, thin film freeze drying, and supercritical processes, including their prospects and associated challenges. With such technologies, it is possible to reshape inhaled therapeutic ingredient delivery, optimizing therapeutic benefits and improving the quality of life for patients with respiratory diseases and beyond.

Endocytosis inhibitors block SARS-CoV-2 pseudoparticle infection of mink lung epithelium

Introduction

Both spill over and spill back of SARS-CoV-2 virus have been reported on mink farms in Europe and the United States. Zoonosis is a public health concern as dangerous mutated forms of the virus could be introduced into the human population through spillback.

Methods

The purpose of our study was to determine the SARS-CoV-2 entry mechanism using the mink lung epithelial cell line (Mv1Lu) and to block entry with drug inhibitors.

Results

Mv1Lu cells were susceptible to SARS-CoV-2 viral pseudoparticle infection, validating them as a suitable disease model for COVID-19. Inhibitors of TMPRSS2 and of endocytosis, two pathways of viral entry, were tested to identify those that blocked infection. TMPRSS2 inhibitors had minimal impact, which can be explained by the apparent lack of activity of this enzyme in the mink and its localization within the cell, not on the cell surface.

Discussion

Dyngo4a, a small molecule endocytosis inhibitor, significantly reduced infection, supporting the conclusion that the entry of the SARS-CoV-2 virus into Mv1Lu cells occurs primarily through endocytosis. The small molecule inhibitors that were effective in this study could potentially be used therapeutically to prevent SARS-CoV-2 infection in mink populations. This study will facilitate the development of therapeutics to prevent zoonotic transmission of SARS-CoV-2 variants to other animals, including humans.

In silico identification of five binding sites on the SARS-CoV-2 spike protein and selection of seven ligands for such sites

To contribute to the development of products capable of complexing with the SARS-CoV-2 spike protein, and thus preventing the virus from entering the host cell, this work aimed at discovering binding sites in the whole protein structure, as well as selecting substances capable of binding efficiently to such sites. Initially, the three-dimensional structure of the protein, with all receptor binding domains in the closed state, underwent blind docking with 38 substances potentially capable of binding to this protein according to the literature. This allowed the identification of five binding sites. Then, those substances with more affinities for these sites underwent pharmacophoric search in the ZINC15 database. The 14,329 substances selected from ZINC15 were subjected to docking to the five selected sites of the spike protein. The ligands with more affinities for the protein sites, as well as the selected sites themselves, were used in the de novo design of new ligands that were also docked to the binding sites of the protein. The best ligands, regardless of their origins, were used to form complexes with the spike protein, which were subsequently used in molecular dynamics simulations and calculations of ligands affinities to the protein through the molecular mechanics/Poisson-Boltzmann surface area method (MMPBSA). Seven substances with good affinities to the spike protein (-12.9 to -20.6 kcal/mol), satisfactory druggability (Bioavailability score: 0.17 to 0.55), and low acute toxicity to mice (LD50: 751 to 1421 mg/kg) were selected as potentially useful for the future development of new products to manage COVID-19 infections.Communicated by Ramaswamy H. Sarma.

An inhaled ACE2 decoy confers protection against SARS-CoV-2 infection in preclinical models

The Omicron variant continuously evolves under the humoral immune pressure exerted by vaccination and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and the resulting Omicron subvariants display further immune evasion and antibody escape. An engineered angiotensin-converting enzyme 2 (ACE2) decoy composed of high-affinity ACE2 and an IgG1 Fc domain could offer an alternative modality to neutralize SARS-CoV-2. We previously reported its broad spectrum and therapeutic potential in rodent models. Here, we demonstrate that the engineered ACE2 decoy retains neutralization activity against Omicron subvariants, including the currently emerging XBB and BQ.1 strains, which completely evade antibodies currently in clinical use. SARS-CoV-2, under the suboptimal concentration of neutralizing drugs, generated SARS-CoV-2 mutants escaping wild-type ACE2 decoy and monoclonal antibodies, whereas no escape mutant emerged against the engineered ACE2 decoy. Furthermore, inhalation of aerosolized decoys improved the outcomes of rodents infected with SARS-CoV-2 at a 20-fold lower dose than that of intravenous administration. Last, the engineered ACE2 decoy exhibited therapeutic efficacy for cynomolgus macaques infected with SARS-CoV-2. These results indicate that this engineered ACE2 decoy represents a promising therapeutic strategy to overcome immune-evading SARS-CoV-2 variants and that liquid aerosol inhalation could be considered as a noninvasive approach to enhance the efficacy of COVID-19 treatments.

World's First Experience of the Low-Dose Radionuclide Inhalation Therapy in the Treatment of COVID-19-Associated Viral Pneumonia: Phase 1/2 Clinical Trial

OBJECTIVE

Previously, low-dose radiation therapy was used for pneumonia treatment. We aimed to investigate the safety and effectiveness of carbon nanoparticles labeled with Technetium isotope (99mTc) in a form of ultradispersed aerosol in combination with standard COVID-19 therapy. The study was a randomized phase 1 and phase 2 clinical trial of low-dose radionuclide inhalation therapy for patients with COVID-19 related pneumonia.

METHODS

We enrolled 47 patients with confirmed COVID-19 infection and early laboratory signs of cytokine storm and randomized them into the Treatment and Control groups. We analyzed blood parameters reflecting the COVID-19 severity and inflammatory response.

RESULTS

Low-dose 99mTc-labeled inhalation showed a minimal accumulation of radionuclide in lungs in healthy volunteers. We observed no significant differences between the groups before treatment in WBC-count, D-dimer, CRP, Ferritin or LDH levels. We found that Ferritin and LDH levels significantly raised after the 7th day follow-up only in the Control group (p < 0.0001 and p = 0.0005, respectively), while mean values of the same indicators did not change in patients in the Treatment group after the radionuclide treatment. D-dimer values also lowered in the radionuclide treated group, however, this effect was not statistically significant. Furthermore, we observed a significant decrease in CD19+ cell counts in patients of the radionuclide-treated group.

CONCLUSION

Inhalation low-dose radionuclide therapy of 99mTc aerosol affects the major prognostic indicators of COVID-19- related pneumonia restraining inflammatory response. Overall, we identified no evidence of major adverse events in the group receiving radionuclide.

COVID-19 Therapeutic Potential of Natural Products

Despite the fact that coronavirus disease 2019 (COVID-19) treatment and management are now considerably regulated, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still one of the leading causes of death in 2022. The availability of COVID-19 vaccines, FDA-approved antivirals, and monoclonal antibodies in low-income countries still poses an issue to be addressed. Natural products, particularly traditional Chinese medicines (TCMs) and medicinal plant extracts (or their active component), have challenged the dominance of drug repurposing and synthetic compound libraries in COVID-19 therapeutics. Their abundant resources and excellent antiviral performance make natural products a relatively cheap and readily available alternative for COVID-19 therapeutics. Here, we deliberately review the anti-SARS-CoV-2 mechanisms of the natural products, their potency (pharmacological profiles), and application strategies for COVID-19 intervention. In light of their advantages, this review is intended to acknowledge the potential of natural products as COVID-19 therapeutic candidates.

Targeted delivery of inhalable drug particles in the tracheobronchial tree model of a pediatric patient with bronchopneumonia: A numerical study

Pneumonia is a common cause of hospitalization and death in children worldwide. Inhalation therapy is one of the methods treating pneumonia However, there are limited studies that distinguish between the physiology of children and adults, especially with respect to targeted drug delivery. A tracheobronchial (TB) tree model of an 11-year-old child with bronchopneumonia is selected as a testbed for in silico trials of targeted drug delivery. The airflow and particle transport are solved by the computational fluid dynamics method at an airflow rate of 15 LPM. The results indicate that the distribution of deposited particles shows aggregation on the particle release map. Point-source aerosol release (PSAR) method can significantly reduce the deposition efficiency (DE) of particles in the TB tree model. Specifically, the PSAR method can reduce the DE of large particles (i.e., 7.5 µm and 10 µm) by 7.57% and 9.61%, respectively. This enables rapid design of patient-specific treatment for different population age groups and different airway diseases.

Effects of Essential Oils and Fragrant Compounds on Appetite: A Systematic Review

Appetite dysregulation is one of the factors contributing to anorexia, bulimia nervosa, obesity, and diabetes. Essential oils or fragrant compounds have been proven to regulate food intake and energy expenditure; hence, this study aimed to summarize their effects on appetite and the underlying mechanisms. The PubMed and Web of Science databases were searched until July 2022. Only two of the 41 studies were performed clinically, and the remaining 39 used animal models. Oral administration was the most common route, and a dosage range of 100-2000 mg/kg for mice or 2-32 mg/kg for rats was applied, with a duration of 12 days to 4 weeks, followed by inhalation (10^-6-10^-3 mg/cage or 10^-9-10^-2 mg/cm³ within 1 h). Approximately 11 essential oil samples and 22 fragrant compounds were found to increase appetite, while 12 essential oils and seven compounds decreased appetite. These fragrant components can exert appetite-regulating effects via leptin resistance, the activity of sympathetic/parasympathetic nerves, or the mRNA expression of neuropeptide Y (NPY)/agouti-related protein (AgRP), cocaine- and amphetamine-regulated transcript (CART)/proopiomelanocortin (POMC) in the hypothalamus. Fragrance memory and cognitive processes may also play roles in appetite regulation. The findings of this study accentuate the potential of essential oils and fragrant compounds to regulate appetite and eating disorders.

Dry Powder Inhaler with the technical and practical obstacles, and forthcoming platform strategies

A Dry Powder Inhaler (DPI) is a technique as well as a device used to inhale formulation which is in the form of dry powder, and is inhaled through the nose or mouth. It was developed for the purpose of treating conditions like chronic obstructive pulmonary disease (COPD), Asthma, and even cystic fibrosis etc. The aim of the review is to discuss the different methods of preparation of dry powders along with the characterization of DPI. Here we present the outline of different methods like supercritical fluid extraction (SCF), spray drying, and milling. The review focussed on various devices including single and multi-dose devices used in the DPI. It also highlights on recent advances in the DPI including nano particulate system, siRNA-based medication, liposomes, and pro-liposomes based delivery. In COVID-19 silver nanoparticles-based DPIs provide very prominent results in the infected lungs. Moreover, this review states that the AI-based DPI development provides and improvement in the bioavailability and effectiveness of the drug along with the role of artificial neural networks (ANN). The study also showed that nasally administered drugs (nose to brain) can easily cross the blood-brain barrier (BBB) and enter the central nervous system (CNS) through the olfactory and trigeminal pathway which provides effective CNS concentrations at lower dosage. It is suggested that DPIs not only target respiratory complications but also treat CNS complications too. This review provides support and guides the researcher in the recent development and evaluation of DPI.

Pulmonary drug delivery: an effective and convenient delivery route to combat COVID-19

The recent outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China has spread rapidly around the world, leading to a widespread and urgent effort to develop and use comprehensive approaches in the treatment of COVID-19. While oral therapy is accepted as an effective and simple method, since the primary site of infection and disease progression of COVID-19 is mainly through the lungs, inhaled drug delivery directly to the lungs may be the most appropriate route of administration. To prevent or treat primary SARS-CoV-2 infections, it is essential to target the virus port of entry in the respiratory tract and airway epithelium, which requires rapid and high-intensity inhibition or control of viral entry or replication. To achieve success in this field, inhalation therapy is the most attractive treatment approach due to efficacy/safety profiles. In this review article, pulmonary drug delivery as a unique treatment option in lung diseases will be briefly reviewed. Then, possible inhalation therapies for the treatment of symptoms of COVID-19 will be discussed and the results of clinical trials will be presented. By pulmonary delivery of the currently approved drugs for COVID-19, efficacy of the treatment would be improved along with reducing systemic side effects.

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.

SARS-CoV-2 spike and ACE2 entanglement-like binding

We describe the binding between the glycoprotein Spike of SARS-CoV-2 and the human host cell receptor ACE2 as a quantum circuit, comprising the one-qubit Hadamard quantum logic gate performing the quantum superposition of the S₁ subunit of the Spike protein, and the two-qubit quantum logic gate CNOT, which performs maximum entanglement between the Spike-qubit S₁ and the ACE2 receptor protein. Also, we consider two strategies to prevent the binding process between the Spike-qubit S₁ and the ACE2 receptor. The first one is the use of competitive peptidomimetic inhibitors that can selectively bind to the receptor binding domain (RBD) of the Spike glycoprotein with much higher affinity than the cell surface receptor itself. These inhibitors are targeted to the CNOT quantum logic gate and will get maximally entangled with the S₁ qubit in place of the natural ACE2 receptor. The second one is to use covalent inhibitors, which will destroy S₁ by acting as a projective quantum measurement. Finally, the conjecture that S₁ is a quantum bio-robot is formulated.

The potential impact of nanomedicine on COVID-19-induced thrombosis

Extensive reports of pulmonary embolisms, ischaemic stroke and myocardial infarctions caused by coronavirus disease 2019 (COVID-19), as well as a significantly increased long-term risk of cardiovascular diseases in COVID-19 survivors, have highlighted severe deficiencies in our understanding of thromboinflammation and the need for new therapeutic options. Due to the complexity of the immunothrombosis pathophysiology, the efficacy of treatment with conventional anti-thrombotic medication is questioned. Thrombolytics do appear efficacious, but are hindered by severe bleeding risks, limiting their use. Nanomedicine can have profound impact in this context, protecting delicate (bio)pharmaceuticals from degradation en route and enabling delivery in a targeted and on demand manner. We provide an overview of the most promising nanocarrier systems and design strategies that may be adapted to develop nanomedicine for COVID-19-induced thromboinflammation, including dual-therapeutic approaches with antiviral and immunosuppressants. Resultant targeted and side-effect-free treatment may aid greatly in the fight against the ongoing COVID-19 pandemic.

In vitro model for investigating aerosol dispersion in a simulated COVID-19 patient during high-flow nasal cannula treatment

The use of high-flow nasal cannula in the treatment of COVID-19 infected patients has proven to be a valuable treatment option to improve oxygenation. Early in the pandemic, there were concerns for the degree of risk of disease transmission to health care workers utilizing these treatments that are considered aerosol generating procedures. This study developed an in vitro model to examine the release of simulated patient-derived bioaerosol with and without high-flow nasal cannula at gas flow rates of 30 and 50 L/min. Aerosol dispersion was evaluated at 30 and 90 cm distances. Reduction of transmission risk was assessed using a surgical facemask on the manikin. Results indicated that the use of a facemask facilitated a 94-95% reduction in exhaled aerosol concentration at 30 cm and 22-60% reduction for 90 cm distance across both gas flow rates. This bench study confirms that this in vitro model can be used as a tool to assess the risk of disease transmission during aerosol generating procedures in a simulated patient and to test factors to mitigate the risk.

Nebulized mRNA-Encoded Antibodies Protect Hamsters from SARS-CoV-2 Infection

Despite the success of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccines, there remains a clear need for new classes of preventatives for respiratory viral infections due to vaccine hesitancy, lack of sterilizing immunity, and for at-risk patient populations, including the immunocompromised. While many neutralizing antibodies have been identified, and several approved, to treat COVID-19, systemic delivery, large doses, and high costs have the potential to limit their widespread use, especially in low- and middle-income countries. To use these antibodies more efficiently, an inhalable formulation is developed that allows for the expression of mRNA-encoded, membrane-anchored neutralizing antibodies in the lung to mitigate SARS-CoV-2 infections. First, the ability of mRNA-encoded, membrane-anchored, anti-SARS-CoV-2 antibodies to prevent infections in vitro is demonstrated. Next, it is demonstrated that nebulizer-based delivery of these mRNA-expressed neutralizing antibodies potently abrogates disease in the hamster model. Overall, these results support the use of nebulizer-based mRNA expression of neutralizing antibodies as a new paradigm for mitigating respiratory virus infections.

Dissolution and Absorption of Inhaled Drug Particles in the Lungs

Dry powder inhalation therapy has been effective in treating localized lung diseases such asthma, chronic obstructive pulmonary diseases (COPD), cystic fibrosis and lung infections. In vitro characterization of dry powder formulations includes the determination of physicochemical nature and aerosol performance of powder particles. The relationship between particle properties (size, shape, surface morphology, porosity, solid state nature, and surface hydrophobicity) and aerosol performance of an inhalable dry powder formulation has been well established. However, unlike oral formulations, there is no standard dissolution method for evaluating the dissolution behavior of the inhalable dry powder particles in the lungs. This review focuses on various dissolution systems and absorption models, which have been developed to evaluate dry powder formulations. It covers a summary of airway epithelium, hurdles to developing an in vitro dissolution method for the inhaled dry powder particles, fine particle dose collection methods, various in vitro dissolution testing methods developed for dry powder particles, and models commonly used to study absorption of inhaled drug.

Progress on Thin Film Freezing Technology for Dry Powder Inhalation Formulations

The surface drying process is an important technology in the pharmaceutical, biomedical, and food industries. The final stage of formulation development (i.e., the drying process) faces several challenges, and overall mastering depends on the end step. The advent of new emerging technologies paved the way for commercialization. Thin film freezing (TFF) is a new emerging freeze-drying technique available for various treatment modalities in drug delivery. TFF has now been used for the commercialization of pharmaceuticals, food, and biopharmaceutical products. The present review highlights the fundamentals of TFF along with modulated techniques used for drying pharmaceuticals and biopharmaceuticals. Furthermore, we have covered various therapeutic applications of TFF technology in the development of nanoformulations, dry powder for inhalations and vaccines. TFF holds promise in delivering therapeutics for lung diseases such as fungal infection, bacterial infection, lung dysfunction, and pneumonia.

Formulation, Device, and Clinical Factors Influencing the Targeted Delivery of COVID-19 Vaccines to the Lungs

The COVID-19 pandemic has proven to be an unprecedented health crisis in the human history with more than 5 million deaths worldwide caused to the SARS-CoV-2 and its variants ( https://www.who.int/emergencies/diseases/novel-coronavirus-2019 ). The currently authorized lipid nanoparticle (LNP)-encapsulated mRNA vaccines have been shown to have more than 90% vaccine efficacy at preventing COVID-19 illness (Baden et al. New England J Med 384(5):403-416, 2021; Thomas et al., 2021). In addition to vaccines, other small molecules belonging to the class of anti-viral and anti-inflammatory compounds have also been prescribed to reduce the viral proliferation and the associated cytokine storm. These anti-viral and anti-inflammatory compounds have also been shown to be effective in reducing COVID-19 exacerbations especially in reducing the host inflammatory response to SARS-CoV-2. However, all of the currently FDA-authorized vaccines for COVID-19 are meant for intramuscular injection directly into the systemic circulation. Also, most of the small molecules investigated for their anti-COVID-19 efficacy have also been explored using the intravenous route with a few of them explored for the inhalation route (Ramakrishnan et al. Lancet Respir Med 9:763-772, 2021; Horby et al. N Engl J Med 384(8):693-704, 2021). The fact that the SARS-CoV-2 enters the human body mainly via the nasal and airway route resulting in the lungs being the primary organs of infection as characterized by acute respiratory distress syndrome (ARDS)-mediated cytokine storm in the alveolar region has made the inhalation route gain significant attention for the purposes of targeting both vaccines and small molecules to the lungs (Mitchell et al., J Aerosol Med Pulm Drug Deliv 33(4):235-8, 2020). While there have been many studies reporting the safety and efficacy of targeting various therapeutics to the lungs to treat COVID-19, there is still a need to match the choice of inhalation formulation and the delivery device platform itself with the patient-related factors like breathing pattern and respiratory rate as seen in a clinical setting. In that perspective, this review aims to describe the various formulation and patient-related clinical factors that can play an important role in the judicious choice of the inhalation delivery platforms or devices for the development of inhaled COVID-19 vaccines.

Oral inhalation of cannabidiol delivered from a metered dose inhaler to alleviate cytokine production induced by SARS-CoV-2 and pollutants

Cannabidiol (CBD) was formulated as a metered dose inhaler (CBD-MDI) and evaluated in vitro for its efficacy as an inhaled dosage form against inflammation caused by the SARS-CoV-2 virus, lipopolysaccharide (LPS) from Escherichia coli, silica particles, nicotine, and coal tar. A CBD-MDI formulation was prepared with 50 mg of CBD in 10 mL for a CBD dose of 250 μg/puff. The formulation ingredients included CBD, absolute ethanol as a cosolvent, and HFA-134a as the propellant. High aerosol performance of CBD-MDI was obtained with mass median aerodynamic diameter of 1.25 ± 0.01 μm, geometric standard deviation of 1.75 ± 0.00, emitted dose of 244.7 ± 2.1 μg, and fine particle dose of 122.0 ± 1.6 μg. The cytotoxicity and anti-inflammatory effectiveness of CBD-MDI were performed in alveolar macrophage (NR8383) and co-culture of alveolar macrophage (NR8383) and human lung adenocarcinoma (A549) cell line. CBD delivered from an MDI was safe on respiratory cells and did not trigger an immune response in alveolar macrophages. CBD-MDI effectively reduced the generation of cytokines in immune cells treated with viral antigen S-RBD, bacterial antigen LPS, silica particles, and coal tar. The efficacy of CBD-MDI was comparable to budesonide. Furthermore, the findings demonstrated that the use of CBD-MDI was more effective in treatment rather than prevention when inflammation was induced by either a viral or bacterial stimulant.

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.

A randomized, open-label trial of combined nitazoxanide and atazanavir/ritonavir for mild to moderate COVID-19

Background

The nitazoxanide plus atazanavir/ritonavir for COVID-19 (NACOVID) trial investigated the efficacy and safety of repurposed nitazoxanide combined with atazanavir/ritonavir for COVID-19.

Methods

This is a pilot, randomized, open-label multicenter trial conducted in Nigeria. Mild to moderate COVID-19 patients were randomly assigned to receive standard of care (SoC) or SoC plus a 14-day course of nitazoxanide (1,000 mg b.i.d.) and atazanavir/ritonavir (300/100 mg od) and followed through day 28. Study endpoints included time to clinical improvement, SARS-CoV-2 viral load change, and time to complete symptom resolution. Safety and pharmacokinetics were also evaluated (ClinicalTrials.gov ID: NCT04459286).

Results

There was no difference in time to clinical improvement between the SoC (n = 26) and SoC plus intervention arms (n = 31; Cox proportional hazards regression analysis adjusted hazard ratio, aHR = 0.898, 95% CI: 0.492-1.638, p = 0.725). No difference was observed in the pattern of saliva SARS-CoV-2 viral load changes from days 2-28 in the 35% of patients with detectable virus at baseline (20/57) (aHR = 0.948, 95% CI: 0.341-2.636, p = 0.919). There was no significant difference in time to complete symptom resolution (aHR = 0.535, 95% CI: 0.251-1.140, p = 0.105). Atazanavir/ritonavir increased tizoxanide plasma exposure by 68% and median trough plasma concentration was 1,546 ng/ml (95% CI: 797-2,557), above its putative EC90 in 54% of patients. Tizoxanide was undetectable in saliva.

Conclusion

Nitazoxanide co-administered with atazanavir/ritonavir was safe but not better than standard of care in treating COVID-19. These findings should be interpreted in the context of incomplete enrollment (64%) and the limited number of patients with detectable SARS-CoV-2 in saliva at baseline in this trial.

Clinical trial registration

[https://clinicaltrials.gov/ct2/show/NCT04459286], identifier [NCT04459286].

Inhaled therapy for COVID-19: Considerations of drugs, formulations and devices

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent responsible for the COVID-19 pandemic, has outspread at full tilt across the world. Although several effective vaccines continue to be deployed, reliable antiviral treatments have yet to be developed against this disease. Currently, available therapeutics for COVID-19 include repurposed, and a few novel drugs. Many drugs have been promising in preclinical studies, but a majority of these drugs have shown little or no efficacy in clinical studies. One of the major reasons is the insufficient drug concentration in the lung, the primary target site of infection for SARS-CoV-2, from the administration of drugs through oral or intravenous routes. Higher effective doses administered through these routes could also lead to adverse side effects. For this reason, inhaled treatments are being tested as an efficient approach for COVID-19, allowing lower doses of drugs ensuring higher concentrations of the drug(s) in the lung. The inhaled treatment combining two or more antiviral drugs will increase potency and reduce the possibility of selecting for SARS-CoV-2 variants with reduced drug susceptibility. Finally, the appropriate drug combination needs to be delivered using a suitable system. Here, we review the current treatment for COVID-19 and their limitations, discussing the advantages of mono and combinational inhaled therapy with a brief outline of the recently reformulated anti-SARS-CoV-2 agents as inhaled formulations. The selection of appropriate delivery devices for inhalation and associated key considerations including the formulation challenges are also discussed.

Manipulation of Spray-Drying Conditions to Develop an Inhalable Ivermectin Dry Powder

SARS-CoV-2, the causative agent of COVID-19, predominantly affects the respiratory tract. As a consequence, it seems intuitive to develop antiviral agents capable of targeting the virus right on its main anatomical site of replication. Ivermectin, a U.S. FDA-approved anti-parasitic drug, was originally shown to inhibit SARS-CoV-2 replication in vitro, albeit at relatively high concentrations, which is difficult to achieve in the lung. In this study, we tested the spray-drying conditions to develop an inhalable dry powder formulation that could ensure sufficient antiviral drug concentrations, which are difficult to achieve in the lungs based on the oral dosage used in clinical trials. Here, by using ivermectin as a proof-of-concept, we evaluated spray-drying conditions that could lead to the development of antivirals in an inhalable dry powder formulation, which could then be used to ensure sufficient drug concentrations in the lung. Thus, we used ivermectin in proof-of-principle experiments to evaluate our system, including physical characterization and in vitro aerosolization of prepared dry powder. The ivermectin dry powder was prepared with a mini spray-dryer (Buchi B-290), using a 23 factorial design and manipulating spray-drying conditions such as feed concentration (0.2% w/v and 0.8% w/v), inlet temperature (80 °C and 100 °C) and presence/absence of L-leucine (0% and 10%). The prepared dry powder was in the size range of 1−5 μm and amorphous in nature with wrinkle morphology. We observed a higher fine particle fraction (82.5 ± 1.4%) in high feed concentration (0.8% w/v), high inlet temperature (100 °C) and the presence of L-leucine (10% w/w). The stability study conducted for 28 days confirmed that the spray-dried powder was stable at 25 ± 2 °C/<15% RH and 25 ± 2 °C/ 53% RH. Interestingly, the ivermectin dry powder formulation inhibited SARS-CoV-2 replication in vitro with a potency similar to ivermectin solution (EC50 values of 15.8 µM and 14.1 µM, respectively), with a comparable cell toxicity profile in Calu-3 cells. In summary, we were able to manipulate the spray-drying conditions to develop an effective ivermectin inhalable dry powder. Ongoing studies based on this system will allow the development of novel formulations based on single or combinations of drugs that could be used to inhibit SARS-CoV-2 replication in the respiratory tract.

Design, Synthesis, and Evaluation of Lung-Retentive Prodrugs for Extending the Lung Tissue Retention of Inhaled Drugs

A major limitation of pulmonary delivery is that drugs can exhibit suboptimal pharmacokinetic profiles resulting from rapid elimination from the pulmonary tissue. This can lead to systemic side effects and a short duration of action. A series of dibasic dipeptides attached to the poorly lung-retentive muscarinic M3 receptor antagonist piperidin-4-yl 2-hydroxy-2,2-diphenylacetate (1) through a pH-sensitive-linking group have been evaluated. Extensive optimization resulted in 1-(((R)-2-((S)-2,6-diaminohexanamido)-3,3-dimethylbutanoyl)oxy)ethyl 4-(2-hydroxy-2,2-diphenylacetoxy)piperidine-1-carboxylate (23), which combined very good in vitro stability and very high rat lung binding. Compound 23 progressed to pharmacokinetic studies in rats, where, at 24 h post dosing in the rat lung, the total lung concentration of 23 was 31.2 μM. In addition, high levels of liberated drug 1 were still detected locally, demonstrating the benefit of this novel prodrug approach for increasing the apparent pharmacokinetic half-life of drugs in the lungs following pulmonary dosing.

Targeted delivery of inhalable drug particles in a patient-specific tracheobronchial tree with moderate COVID-19: A numerical study

The coronavirus disease 2019 (COVID-19) pandemic has led to severe social and economic disruption worldwide. Although currently no consent has been reached on a specific therapy that can treat COVID-19 effectively, several inhalation therapy strategies have been proposed to inhibit SARS-CoV-2 infection. These strategies include inhalations of antiviral drugs, anti-inflammatory drugs, and vaccines. To investigate how to enhance the therapeutic effect by increasing the delivery efficiency (DE) of the inhaled aerosolized drug particles, a patient-specific tracheobronchial (TB) tree from the trachea up to generation 6 (G6) with moderate COVID-19 symptoms was selected as a testbed for the in silico trials of targeted drug delivery to the lung regions with pneumonia alba, i.e., the severely affected lung segments (SALS). The 3D TB tree geometry was reconstructed from spiral computed tomography (CT) scanned images. The airflow field and particle trajectories were solved using a computational fluid dynamics (CFD) based Euler-Lagrange model at an inhalation flow rate of 15 L/min. Particle release maps, which record the deposition locations of the released particles, were obtained at the inlet according to the particle trajectories. Simulation results show that particles with different diameters have similar release maps for targeted delivery to SALS. Point-source aerosol release (PSAR) method can significantly enhance the DE into the SALS. A C++ program has been developed to optimize the location of the PSAR tube. The optimized simulations indicate that the PSAR approach can at least increase the DE of the SALS by a factor of 3.2× higher than conventional random-release drug-aerosol inhalation. The presence of the PSAR tube only leads to a 7.12% change in DE of the SALS. This enables the fast design of a patient-specific treatment for reginal lung diseases.

Post-COVID Syndrome: The Research Progress in the Treatment of Pulmonary sequelae after COVID-19 Infection

Post-COVID syndrome or long COVID is defined as the persistence of symptoms after confirmed SARS-CoV-2 infection, the pathogen responsible for coronavirus disease. The content herein presented reviews the reported long-term consequences and aftereffects of COVID-19 infection and the potential strategies to adopt for their management. Recent studies have shown that severe forms of COVID-19 can progress into acute respiratory distress syndrome (ARDS), a predisposing factor of pulmonary fibrosis that can irreversibly compromise respiratory function. Considering that the most serious complications are observed in the airways, the inhalation delivery of drugs directly to the lungs should be preferred, since it allows to lower the dose and systemic side effects. Although further studies are needed to optimize these techniques, recent studies have also shown the importance of in vitro models to recreate the SARS-CoV-2 infection and study its sequelae. The information reported suggests the necessity to develop new inhalation therapies in order to improve the quality of life of patients who suffer from this condition.

COVID-19 vaccine development: milestones, lessons and prospects

With the constantly mutating of SARS-CoV-2 and the emergence of Variants of Concern (VOC), the implementation of vaccination is critically important. Existing SARS-CoV-2 vaccines mainly include inactivated, live attenuated, viral vector, protein subunit, RNA, DNA, and virus-like particle (VLP) vaccines. Viral vector vaccines, protein subunit vaccines, and mRNA vaccines may induce additional cellular or humoral immune regulations, including Th cell responses and germinal center responses, and form relevant memory cells, greatly improving their efficiency. However, some viral vector or mRNA vaccines may be associated with complications like thrombocytopenia and myocarditis, raising concerns about the safety of these COVID-19 vaccines. Here, we systemically assess the safety and efficacy of COVID-19 vaccines, including the possible complications and different effects on pregnant women, the elderly, people with immune diseases and acquired immunodeficiency syndrome (AIDS), transplant recipients, and cancer patients. Based on the current analysis, governments and relevant agencies are recommended to continue to advance the vaccine immunization process. Simultaneously, special attention should be paid to the health status of the vaccines, timely treatment of complications, vaccine development, and ensuring the lives and health of patients. In addition, available measures such as mix-and-match vaccination, developing new vaccines like nanoparticle vaccines, and optimizing immune adjuvant to improve vaccine safety and efficacy could be considered.

Emerging small molecule antivirals may fit neatly into COVID-19 treatment

Numerous treatments exist for COVID-19, the illness caused by SARS-CoV-2 virus, although most are not well established; among these are several small molecule antiviral agents. Intravenous remdesivir is an established treatment worldwide for inpatients and in some countries is also available for use in non-hospitalised high risk patients to prevent progression to severe disease and hospitalization. Oral molnupiravir and oral nirmatrelvir-ritonavir are also available in several countries to prevent progression to severe disease and hospitalization for high-risk outpatients. Many other antiviral small molecules that may have therapeutic potential are under investigation in clinical trials. This article provides a summary of key molecular targets, pharmacology and preliminary data on the efficacy and safety of small molecule antiviral agents being investigated for the treatment of COVID-19.

Polymeric nanoparticles and nanomicelles of hydroxychloroquine co-loaded with azithromycin potentiate anti-SARS-CoV-2 effect

The outbreak of coronavirus (COVID-19) has put the world in an unprecedented scenario. To reestablish the world routine as promote the effective treatment of this disease, the world is looking for new (and old) drug that can efficiently kill the virus. In this study, we have developed two nanosystems: polymeric nanoparticles and nanomicelles-based on hydroxychloroquine and azithromycin. The nanosystem was fully characterized by AFM and DLS techniques. Also, the nanosystems were radiolabeled with 99mTc and pulmonary applied (installation) in vivo to evaluate the biological behavior. The toxicity of both nanosystem were evaluated in primary cells (FGH). Finally, both nanosystems were evaluated in vitro against the SARS-CoV-2. The results demonstrated that the methodology used to produce the nanomicelles and the nanoparticle was efficient, the characterization showed a nanoparticle with a spherical shape and a medium size of 390 nm and a nanomicelle also with a spherical shape and a medium size of 602 nm. The nanomicelles were more efficient (~ 70%) against SARS-CoV-2 than the nanoparticles. The radiolabeling process with 99mTc was efficient (> 95%) in both nanosystems and the pulmonary application demonstrated to be a viable route for both nanosystems with a local retention time of approximately, 24 h. None of the nanosystems showed cytotoxic effect on FGH cells, even in high doses, corroborating the safety of both nanosystems. Thus, claiming the benefits of the nanotechnology, especially with regard the reduced adverse we believe that the use of nanosystems for COVID-19 treatment can be an optimized choice.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40097-022-00476-3.

Efficacy of Inhaled Ciclesonide for Outpatient Treatment of Adolescents and Adults With Symptomatic COVID-19: A Randomized Clinical Trial

Importance

Systemic corticosteroids are commonly used in treating severe COVID-19. However, the role of inhaled corticosteroids in the treatment of patients with mild to moderate disease is less clear.

Objective

To determine the efficacy of the inhaled steroid ciclesonide in reducing the time to alleviation of all COVID-19-related symptoms among nonhospitalized participants with symptomatic COVID-19 infection.

Design, Setting, and Participants

This phase 3, multicenter, double-blind, randomized clinical trial was conducted at 10 centers throughout the US and assessed the safety and efficacy of a ciclesonide metered-dose inhaler (MDI) for treating nonhospitalized participants with symptomatic COVID-19 infection who were screened from June 11, 2020, to November 3, 2020.

Interventions

Participants were randomly assigned to receive ciclesonide MDI, 160 μg per actuation, for a total of 2 actuations twice a day (total daily dose, 640 μg) or placebo for 30 days.

Main Outcomes and Measures

The primary end point was time to alleviation of all COVID-19-related symptoms (cough, dyspnea, chills, feeling feverish, repeated shaking with chills, muscle pain, headache, sore throat, and new loss of taste or smell) by day 30. Secondary end points included subsequent emergency department visits or hospital admissions for reasons attributable to COVID-19.

Results

A total of 413 participants were screened and 400 (96.9%) were enrolled and randomized (197 [49.3%] in the ciclesonide arm and 203 [50.7%] in the placebo arm; mean [SD] age, 43.3 [16.9] years; 221 [55.3%] female; 2 [0.5%] Asian, 47 [11.8%] Black or African American, 3 [0.8%] Native Hawaiian or other Pacific Islander, 345 [86.3%] White, and 1 multiracial individuals [0.3%]; 172 Hispanic or Latino individuals [43.0%]). The median time to alleviation of all COVID-19-related symptoms was 19.0 days (95% CI, 14.0-21.0) in the ciclesonide arm and 19.0 days (95% CI, 16.0-23.0) in the placebo arm. There was no difference in resolution of all symptoms by day 30 (odds ratio, 1.28; 95% CI, 0.84-1.97). Participants who were treated with ciclesonide had fewer subsequent emergency department visits or hospital admissions for reasons related to COVID-19 (odds ratio, 0.18; 95% CI, 0.04-0.85). No participants died during the study.

Conclusions and Relevance

The results of this randomized clinical trial demonstrated that ciclesonide did not achieve the primary efficacy end point of reduced time to alleviation of all COVID-19-related symptoms.

Trial Registration

ClinicalTrials.gov Identifier: NCT04377711.

Innovations and development of Covid-19 vaccines: A patent review

More than 125 million confirmed cases of COVID-19 have been reported globally with rising cases in all countries since the first case was reported. A vaccine is the best measure for the effective prevention and control of COVID-19. There are more than 292 COVID-19 candidates' vaccines being developed as of July 2021 of which 184 are in human preclinical trials. A patent provides protection and a marketing monopoly to the inventor of an invention for a specified period. Therefore, vaccine developers, including Moderna, BioNTech, Janssen, Inovio, and Gamaleya also filed patent applications for the protection of their vaccines. This review aims to provide an insight into the patent literature of COVID-19 vaccines. The patent search was done using Patentscope and Espacenet databases. The results have revealed that most of the key players have patented their inventive COVID-19 vaccine. Many patent applications related to COVID-19 vaccines developed via different technologies (DNA, RNA, virus, bacteria, and protein subunit) have also been filed. The publication of a normal patent application takes place after 18 months of its filing. Therefore, many patents/patent applications related to the COVID-19 vaccine developed through different technology may come into the public domain in the coming days.

Intranasal Delivery of MVA Vector Vaccine Induces Effective Pulmonary Immunity Against SARS-CoV-2 in Rodents

Antigen-specific tissue-resident memory T cells (Trms) and neutralizing IgA antibodies provide the most effective protection of the lungs from viral infections. To induce those essential components of lung immunity against SARS-CoV-2, we tested various immunization protocols involving intranasal delivery of a novel Modified Vaccinia virus Ankara (MVA)-SARS-2-spike vaccine candidate. We show that a single intranasal MVA-SARS-CoV-2-S application in mice strongly induced pulmonary spike-specific CD8+ T cells, albeit restricted production of neutralizing antibodies. In prime-boost protocols, intranasal booster vaccine delivery proved to be crucial for a massive expansion of systemic and lung tissue-resident spike-specific CD8+ T cells and the development of Th1 - but not Th2 - CD4+ T cells. Likewise, very high titers of IgG and IgA anti-spike antibodies were present in serum and broncho-alveolar lavages that possessed high virus neutralization capacities to all current SARS-CoV-2 variants of concern. Importantly, the MVA-SARS-2-spike vaccine applied in intramuscular priming and intranasal boosting treatment regimen completely protected hamsters from developing SARS-CoV-2 lung infection and pathology. Together, these results identify intramuscular priming followed by respiratory tract boosting with MVA-SARS-2-S as a promising approach for the induction of local, respiratory as well as systemic immune responses suited to protect from SARS-CoV-2 infections.

What Happens to the Immune System after Vaccination or Recovery from COVID-19?

Due to its leading role in fighting infections, the human immune system has been the focus of many studies in the context of Coronavirus disease 2019 (COVID-19). In a worldwide effort, the scientific community has transitioned from reporting about the effects of the novel coronavirus on the human body in the early days of the pandemic to exploring the body's many immunopathological and immunoprotecting properties that have improved disease treatment and enabled the development of vaccines. The aim of this review is to explain what happens to the immune system after recovery from COVID-19 and/or vaccination against SARS-CoV-2, the virus that causes the disease. We detail the way in which the immune system responds to a SARS-CoV-2 infection, including innate and adaptive measures. Then, we describe the role of vaccination, the main types of COVID-19 vaccines and how they protect us. Further, we explain the reason why immunity after COVID-19 infection plus a vaccination appears to induce a stronger response compared with virus exposure alone. Additionally, this review reports some correlates of protection from SARS-CoV-2 infection. In conclusion, we reinforce that vaccination is safe and important in achieving herd immunity.

Physicochemical Characteristics and In Vitro Toxicity/Anti-SARS-CoV-2 Activity of Favipiravir Solid Lipid Nanoparticles (SLNs)

The rise of coronavirus (COVID-19) cases worldwide has driven the need to discover and develop novel therapeutics with superior efficacy to treat this disease. This study aims to develop an innovative aerosolized nano-formulation of favipiravir (FPV) as an anti-viral agent against coronavirus infection. The local delivery of FPV nanoparticles (NPs) via nebulization ensures that the drug can reach the site of infection, the lungs. Solid lipid NPs of favipiravir (FPV-SLNs) were formulated utilizing the hot-evaporation method. The physicochemical formulation properties were evaluated using dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The aerosol formulation performance was evaluated using an Andersen Cascade Impactor (ACI) at a flow rate of 15 L/min. The FPV-SLN formulation's in vitro anti-viral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was also evaluated using the SARS-CoV-2 pathogen (hCoV-19/Egypt/NRC-3/2020 isolate). The FPV-SLNs' morphology was defined utilizing transmission electron microscopy, showing an irregular shape. By means of FPV-SLNs' nebulization, a fine particle fraction of 60.2 ± 1.7% was produced with 60.2 ± 1.7%, and this finding suggests that FPV-SLNs were appropriate for inhalation drug delivery with a particle size of 537.6 ± 55.72 nm. Importantly, the FPV-SLNs showed anti-viral activity against SARS-CoV-2 with CC50 and IC50 values of 449.6 and 29.9 µg/mL, respectively. This study suggests that inhaled solid lipid NPs of favipiravir could potentially be used against coronavirus.

Synthesis, Physicochemical Characterization, In Vitro 2D/3D Human Cell Culture, and In Vitro Aerosol Dispersion Performance of Advanced Spray Dried and Co-Spray Dried Angiotensin (1-7) Peptide and PNA5 with Trehalose as Microparticles/Nanoparticles for Targeted Respiratory Delivery as Dry Powder Inhalers

The peptide hormone Angiotensin (1-7), Ang (1-7) or (Asp-Arg-Val-Tyr-Ile-His-Pro), is an essential component of the renin-angiotensin system (RAS) peripherally and is an agonist of the Mas receptor centrally. Activation of this receptor in the CNS stimulates various biological activities that make the Ang (1-7)/MAS axis a novel therapeutic approach for the treatment of many diseases. The related O-linked glycopeptide, Asp-Arg-Val-Tyr-Ile-His-Ser-(O-β-D-Glc)-amide (PNA5), is a biousian revision of the native peptide hormone Ang (1-7) and shows enhanced stability in vivo and greater levels of brain penetration. We have synthesized the native Ang (1-7) peptide and the glycopeptide, PNA5, and have formulated them for targeted respiratory delivery as inhalable dry powders. Solid phase peptide synthesis (SPPS) successfully produced Ang (1-7) and PNA5. Measurements of solubility and lipophilicity of raw Ang (1-7) and raw PNA5 using experimental and computational approaches confirmed that both the peptide and glycopeptide have high-water solubility and are amphipathic. Advanced organic solution spray drying was used to engineer the particles and produce spray-dried powders (SD) of both the peptide and the glycopeptide, as well as co-spray-dried powders (co-SD) with the non-reducing sugar and pharmaceutical excipient, trehalose. The native peptide, glycopeptide, SD, and co-SD powders were comprehensively characterized, and exhibited distinct glass transitions (Tg) consistent with the amorphous glassy state formation with Tgs that are compatible with use in vivo. The homogeneous particles displayed small sizes in the nanometer size range and low residual water content in the solid-state. Excellent aerosol dispersion performance with a human DPI device was demonstrated. In vitro human cell viability assays showed that Ang (1-7) and PNA5 are biocompatible and safe for different human respiratory and brain cells.