Critical Parameters for Particle-Based Pulmonary Delivery of Chemotherapeutics

Different Carriers for Use in Dry Powder Inhalers: Characteristics of Their Particles

In contemporary times, there has been a rise in the utilization of dry powder inhalers (DPIs) in the management of pulmonary and systemic diseases. These devices underwent a swift advancement in terms of both the equipment utilized and the formulation process. In this review, the carrier physicochemical characteristics that influence DPI performance are discussed, focusing its shape, morphology, size distribution, texture, aerodynamic diameter, density, moisture, adhesive and detachment forces between particles, fine carrier particles, and dry powder aerosolization. To promote the deposition of the active principal ingredient deep within the pulmonary system, advancements have been made in enhancing these factors and surface properties through the application of novel technologies that encompass particle engineering. So far, the most used carrier is lactose showing some advantages and disadvantages, but other substances and systems are being studied with the intention of replacing it. The final objective of this review is to analyze the physicochemical and mechanical characteristics of the different carriers or new delivery systems used in DPI formulations, whether already on the market or still under investigation. [Figure: see text].

Rifabutin loaded inhalable β-glucan microparticle based drug delivery system for pulmonary TB

Inhalable microparticle-based anti TB drug delivery systems are being investigated extensively for Tuberculosis [TB] treatment as they offer efficient and deep lung deposition with several advantages over conventional routes. It can reduce the drug dose, treatment duration and toxic effects and optimize the drug bioavailability. Yeast derived β-glucan is a β-[1-3/1-6] linked biocompatible polymer and used as carrier for various biomolecules. Due to presence of glucan chains, particulate glucans act as PAMP and thereby gets internalized via receptor mediated phagocytosis by the macrophages. In this study, β-glucan microparticles were prepared by adding l-leucine as excipient, and exhibited 70% drug [Rifabutin] loading efficiency. Further, the sizing and SEM data of particles revealed a size of 2-4 µm with spherical dimensions. The FTIR and HPLC data confirmed the β-glucan composition and drug encapsulations efficiency of the particles. The mass median aerodynamic diameter [MMAD] and geometric standard deviation [GSD] data indicated that these particles are inhalable in nature and have better thermal stability as per DSC thermogram. These particles were found to be non-toxic upto a concentration of 80 µg/ml and were found to be readily phagocytosed by human macrophage cells in-vitro as well as in-vivo by lung alveolar macrophage. This study provides a framework for future design of inhalable β-glucan particle based host-directed drug delivery system against pulmonary TB.

Spray dried lipid nanoparticle formulations enable intratracheal delivery of mRNA

RNA therapies have recently taken a giant leap forward with the approval of Onpattro™, a siRNA therapy delivered using a lipid nanoparticle (LNP), and the LNP-enabled mRNA vaccines against COVID-19, which are the first mRNA drugs to reach the marketplace. The latter medicines have illustrated that stability is a significant challenge in the distribution of RNA drugs using non-viral delivery systems, particularly in areas without cold chain storage. Here, we describe a proof-of-concept study on the engineering of an LNP mRNA formulation suitable for spray drying. This process produced a dry powder formulation that maintained stability and preserved mRNA functionality with increased performance compared to liquid formulations stored two weeks at 4 °C. Intratracheal delivery of spray dried LNPs loaded with eGFP mRNA to rats resulted in the production of the eGFP protein in a range of cell types including bronchiolar epithelial cells, macrophages and type II pneumocytes; cell types involved in adaptive immunity and which would be valuable targets for inhaled vaccines against respiratory pathogens. Together, these data show that spray drying of LNPs enhances their stability and may enable RNA delivery to the lung for protein replacement therapy, gene editing, vaccination, and beyond.

Nanostructures for prevention, diagnosis, and treatment of viral respiratory infections: from influenza virus to SARS-CoV-2 variants

Viruses are a major cause of mortality and socio-economic downfall despite the plethora of biopharmaceuticals designed for their eradication. Conventional antiviral therapies are often ineffective. Live-attenuated vaccines can pose a safety risk due to the possibility of pathogen reversion, whereas inactivated viral vaccines and subunit vaccines do not generate robust and sustained immune responses. Recent studies have demonstrated the potential of strategies that combine nanotechnology concepts with the diagnosis, prevention, and treatment of viral infectious diseases. The present review provides a comprehensive introduction to the different strains of viruses involved in respiratory diseases and presents an overview of recent advances in the diagnosis and treatment of viral infections based on nanotechnology concepts and applications. Discussions in diagnostic/therapeutic nanotechnology-based approaches will be focused on H1N1 influenza, respiratory syncytial virus, human parainfluenza virus type 3 infections, as well as COVID-19 infections caused by the SARS-CoV-2 virus Delta variant and new emerging Omicron variant.

On the Physical Stability of Leucine-Containing Spray-Dried Powders for Respiratory Drug Delivery

Carrier-free spray-dried dispersions for pulmonary delivery, for which the demand is growing, frequently require the incorporation of dispersibility-enhancing excipients into the formulations to improve the efficacy of the dosage form. One of the most promising of such excipients, L-leucine, is expected to be approved for inhalation soon and has been studied exhaustively. However, during stability, small fibers protruding from the particles of leucine-containing powders have occasionally been observed. To clarify the origin of these fibers and assess their potential influence on the performance of the powders, three different classes of spray-dried leucine-containing formulation systems were studied over an 8-month accelerated stability program. These systems consisted of a large molecule biologic (bevacizumab) in conjunction with a glass former (trehalose), an amorphous small-molecular mass active (moxidectin), and a crystallizing active (mannitol). It was determined that the appearance of the fibers was due to the presence of small quantities of leucine in higher energy states, either because these were amorphous or present as a less stable crystalline polymorph. It was further shown that the growth of these leucine fibers caused no significant physicochemical instability in the powders. Nor, more importantly, did it decrease their aerosol performance in a dry powder inhaler or reduce the concentration of their active pharmaceutical ingredients.

Liposomes or Extracellular Vesicles: A Comprehensive Comparison of Both Lipid Bilayer Vesicles for Pulmonary Drug Delivery

The rapid and non-invasive pulmonary drug delivery (PDD) has attracted great attention compared to the other routes. However, nanoparticle platforms, like liposomes (LPs) and extracellular vesicles (EVs), require extensive reformulation to suit the requirements of PDD. LPs are artificial vesicles composed of lipid bilayers capable of encapsulating hydrophilic and hydrophobic substances, whereas EVs are natural vesicles secreted by cells. Additionally, novel LPs-EVs hybrid vesicles may confer the best of both. The preparation methods of EVs are distinguished from LPs since they rely mainly on extraction and purification, whereas the LPs are synthesized from their basic ingredients. Similarly, drug loading methods into/onto EVs are distinguished whereby they are cell- or non-cell-based, whereas LPs are loaded via passive or active approaches. This review discusses the progress in LPs and EVs as well as hybrid vesicles with a special focus on PDD. It also provides a perspective comparison between LPs and EVs from various aspects (composition, preparation/extraction, drug loading, and large-scale manufacturing) as well as the future prospects for inhaled therapeutics. In addition, it discusses the challenges that may be encountered in scaling up the production and presents our view regarding the clinical translation of the laboratory findings into commercial products.

Telmisartan Nanosuspension for Inhaled Therapy of COVID-19 Lung Disease and Other Respiratory Infections

Vaccine hesitancy and the occurrence of elusive variants necessitate further treatment options for coronavirus disease 2019 (COVID-19). Accumulated evidence indicates that clinically used hypertensive drugs, angiotensin receptor blockers (ARBs), may benefit patients by mitigating disease severity and/or viral propagation. However, current clinical formulations administered orally pose systemic safety concerns and likely require a very high dose to achieve the desired therapeutic window in the lung. To address these limitations, we have developed a nanosuspension formulation of an ARB, entirely based on clinically approved materials, for inhaled treatment of COVID-19. We confirmed in vitro that our formulation exhibits physiological stability, inherent drug activity, and inhibitory effect against SARV-CoV-2 replication. Our formulation also demonstrates excellent lung pharmacokinetics and acceptable tolerability in rodents and/or nonhuman primates following direct administration into the lung. Thus, we are currently pursuing clinical development of our formulation for its uses in patients with COVID-19 or other respiratory infections.

Towards more efficient inhalable chemotherapy: Fabrication of nanodiamonds-releasing microspheres

Nanodiamonds (NDs) are among the most promising chemotherapy vectors, however, they tend to aggregate upon storage, or when exposed to mild changes in pH or ionic strength. Therefore, fabrication of dried NDs with minimal change in particle size is highly desirable. In this study, we have developed a dried powder form of NDs with controlled particle size to be eligible for pulmonary delivery, after screening different drying protectants for their effect on NDs particle size and surface charge. Results showed that the nanospray-drying process in the presence of mannitol prevented the aggregation of NDs. Nanospray-dried NDs microparticles exhibited an optimal aerodynamic size for pulmonary delivery, and the in vitro aerosol deposition testing showed that NDs-embedded mannitol microspheres could deliver more than half of the emitted fraction to the lower stage of the Twin impinger device; indicating high pulmonary delivery potential. Upon loading NDs with doxorubicin (NDX) prior to spray dryng, they were able to deliver 2.6 times more drug to A549 lung cancer cell line compared to the free drug. Pharmacokinetics study in rats showed that inhaled NDX microparticles could efficiently limit the biodistribution of the drug to the lungs, and minimize the drug fraction reaching the systemic circulation. To conclude, nanospray-dried NDs microparticles present a promising vehicle for the pulmonary delivery of chemotherapeutic agents for treatment of lung cancer.

Advanced formulations and nanotechnology-based approaches for pulmonary delivery of sildenafil: A scoping review

Oral sildenafil (SDF) is used to treat pulmonary arterial hypertension (PAH), and its bioavailability is approximately 40%. Several formulations of nano and microparticles (for pulmonary delivery) are being developed because it is possible to improve characteristics such as release time, bioavailability, dose, frequency, and even directly target the drug to the lungs. This review summarizes the latest SDF drug delivery systems for PAH and explains challenges related to the development, the preclinical, and the clinical studies. A scoping review was conducted by searching electronic databases including PubMed, Scopus, and Web of Science to identify studies published between 2001 and 2021. From 300 articles found, 31 met the inclusion criteria. This review identified colloidal formulations such as polymeric, lipid, and metal-organic framework nanoparticles. Strategies were determined to reach the deep airways such as polymeric microparticles, large porous microparticles, nanocomposites, and nano in microparticles. Finally, aspects related to toxicological, pharmacokinetics, and gaps in information for potential use in humans were discussed. SDF formulations are significant candidates for the treatment of PAH by inhalation. In summation, future preclinical studies are still required in large animals, as there is no particular formulation yet submitted to clinical studies.

Advances in lipid-based pulmonary nanomedicine for the management of inflammatory lung disorders

Inflammatory lung disorders have become one of the fastest growing global healthcare concerns, with more than 500 million annual cases of disorders such as chronic obstructive pulmonary disease, asthma and pulmonary fibrosis. Owing to environmental changes and socioeconomic disparity, the numbers are expected to grow even more in years to come. The therapeutic strategies and approved drugs currently employed in the management of inflammatory lung disorders show dose-dependent resistance and pharmacokinetic limitations. This review comprehensively discusses lipid-based pulmonary nanomedicine as a potential platform to overcome these barriers while ensuring site-specific drug delivery and minimal side effects in nontargeted tissues for the management of noninfectious inflammatory lung disorders.

Pulmonary delivery of osimertinib liposomes for non-small cell lung cancer treatment: formulation development and in vitro evaluation

Osimertinib (OB) is a third-generation irreversible tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR), overexpressed in non-small cell lung cancer. Systemic administration of drug often results in poor drug levels at the primary tumor in the lungs and is associated with systemic side effects. In this study, we developed inhalable OB liposomes that can locally accumulate at the tumor site thereby limiting systemic toxicity. OB was loaded into liposomes via active and passive loading methods. The OB active liposomes achieved a higher encapsulation (78%) compared to passive liposomes (25%). The liposomes (passive and active) exhibited excellent aerosolization performance with an aerodynamic diameter of 4 µm and fine particle fraction of 82%. In H1975 cells, OB active and passive liposomes reduced IC₅₀ by 2.2 and 1.2-fold, respectively, compared to free drug. As the OB active liposomes demonstrated higher cytotoxicity compared to OB passive liposomes, they were further investigated for in vitro anti-cancer activity. The OB active liposomes inhibited tumor cell migration and colonization as determined by the scratch assay and clonogenic assay, respectively. Furthermore, the 3D spheroid studies showed that the liposomes were successful in inhibiting tumor growth. These results highlight the potential of OB liposomes to suppress lung cancer. Owing to these attributes, the inhalable OB liposomes can potentially promote better therapeutic outcomes with limited systemic toxicity.

Trileucine as a dispersibility enhancer of spray-dried inhalable microparticles

The formation of trileucine-containing spray-dried microparticles intended for pulmonary delivery was studied in depth. A single-particle method was employed to study the shell formation characteristics of trileucine in the presence of trehalose as a glass former, and an empirical correlation was proposed to predict the instance of shell formation. A droplet chain instrument was used to produce and collect monodisperse particles to examine morphology and calculate particle density for different levels of trileucine. It was observed that the addition of only 0.5 mg/mL (10% w/w) trileucine to a trehalose system could lower dried particle densities by approximately 1 g/cm³. In addition, a laboratory-scale spray dryer was used to produce batches of trileucine/trehalose powders in the respirable range. Raman spectroscopy demonstrated that both components were completely amorphous. Scanning electron microscopy and time-of-flight secondary ion mass spectrometry were used to study the particle morphologies and surface compositions. For all cases with trileucine, highly rugose particles with trileucine coverages of more than 60% by mass were observed with trileucine feed fractions of as little as 2% w/w. Moreover, it was seen that at lower trileucine content, smaller and larger particles of a polydisperse powder had slightly different surface compositions. The surface activity of trileucine was also modeled via a modified form of the diffusion equation inside an evaporating droplet that took into account initial surface adsorption and eventual surface desorption due to droplet shrinkage. Finally, using the Flory-Huggins theory, it was estimated that at room temperature, liquid-liquid phase separation would start when the trileucine reached an aqueous concentration of about 18 mg/mL. Besides the surface activity of trileucine, this low concentration was assumed to explain the substantial effect of trileucine on the morphology of spray-dried particles due to early phase separation. The methodology proposed in this study can be used in the rational design of trileucine-containing microparticles.

Pulmonary Delivery of Anticancer Drugs via Lipid-Based Nanocarriers for the Treatment of Lung Cancer: An Update

Lung cancer (LC) is the leading cause of cancer-related deaths, responsible for approximately 18.4% of all cancer mortalities in both sexes combined. The use of systemic therapeutics remains one of the primary treatments for LC. However, the therapeutic efficacy of these agents is limited due to their associated severe adverse effects, systemic toxicity and poor selectivity. In contrast, pulmonary delivery of anticancer drugs can provide many advantages over conventional routes. The inhalation route allows the direct delivery of chemotherapeutic agents to the target LC cells with high local concertation that may enhance the antitumor activity and lead to lower dosing and fewer systemic toxicities. Nevertheless, this route faces by many physiological barriers and technological challenges that may significantly affect the lung deposition, retention, and efficacy of anticancer drugs. The use of lipid-based nanocarriers could potentially overcome these problems owing to their unique characteristics, such as the ability to entrap drugs with various physicochemical properties, and their enhanced permeability and retention (EPR) effect for passive targeting. Besides, they can be functionalized with different targeting moieties for active targeting. This article highlights the physiological, physicochemical, and technological considerations for efficient inhalable anticancer delivery using lipid-based nanocarriers and their cutting-edge role in LC treatment.

Nanobased Platforms for Diagnosis and Treatment of COVID-19: From Benchtop to Bedside

Human respiratory viral infections are the leading cause of morbidity and mortality around the world. Among the various respiratory viruses, coronaviruses (e.g., SARS-CoV-2) have created the greatest challenge and most frightening health threat worldwide. Human coronaviruses typically infect the upper respiratory tract, causing illnesses that range from common cold-like symptoms to severe acute respiratory infections. Several promising vaccine formulations have become available since the beginning of 2021. Nevertheless, achievement of herd immunity is still far from being realized. Social distancing remains the only effective measure against SARS-CoV-2 infection. Nanobiotechnology enables the design of nanobiosensors. These nanomedical diagnostic devices have opened new vistas for early detection of viral infections. The present review outlines recent research on the effectiveness of nanoplatforms as diagnostic and antiviral tools against coronaviruses. The biological properties of coronavirus and infected host organs are discussed. The challenges and limitations encountered in combating SARS-CoV-2 are highlighted. Potential nanodevices such as nanosensors, nanobased vaccines, and smart nanomedicines are subsequently presented for combating current and future mutated versions of coronaviruses.

Afatinib-loaded inhalable PLGA nanoparticles for localized therapy of non-small cell lung cancer (NSCLC)-development and in-vitro efficacy

Afatinib (AFA) is a potent aniline-quinazoline derivative, approved by the Food and Drug Administration (FDA) in 2013, as a first-line treatment for metastatic non-small cell lung cancer (NSCLC). However, its clinical application is highly limited by its poor solubility, and consequently low bioavailability. We hypothesize that loading of AFA into biodegradable PLGA nanoparticles for localized inhalational drug delivery will be instrumental in improving therapeutic outcomes in NSCLC patients. Formulated AFA nanoparticles (AFA-NP) were evaluated for physicochemical properties (particle size: 180.2 ± 15.6 nm, zeta potential: - 23.1 ± 0.2 mV, % entrapment efficiency: 34.4 ± 2.3%), formulation stability, in-vitro aerosol deposition behavior, and anticancer efficacy. Stability studies revealed the physicochemical stability of AFA-NP. Moreover, AFA-NP exhibited excellent inhalable properties (mass median aerodynamic diameter (MMAD): 4.7 ± 0.1 μm; fine particle fraction (FPF): 77.8 ± 4.3%), indicating efficient particle deposition in deep lung regions. With respect to in-vitro drug release, AFA-NP showed sustained drug release with cumulative release of 56.8 ± 6.4% after 48 h. Cytotoxic studies revealed that encapsulation of AFA into PLGA nanoparticles significantly enhanced its cytotoxic potential in KRAS-mutated NSCLC cell lines (A549, H460). Cellular uptake studies revealed enhanced internalization of coumarin-loaded nanoparticles compared to plain coumarin in A549. In addition, 3D tumor spheroid studies demonstrated superior efficacy of AFA-NP in tumor penetration and growth inhibition. To conclude, we have established in-vitro efficacy of afatinib-loaded PLGA nanoparticles as inhalable NSCLC therapy, which will be of great significance when designing preclinical and clinical studies. Graphical abstract.

Aerosolized nanoliposomal carrier of remdesivir: an effective alternative for COVID-19 treatment in vitro

Aim: To formulate an aerosolized nanoliposomal carrier for remdesivir (AL-Rem) against coronavirus disease 2019. Methods: AL-Rem was prepared using modified hydration technique. Cytotoxicity in lung adenocarcinoma cells, stability and aerodynamic characteristics of developed liposomes were evaluated. Results: AL-Rem showed high encapsulation efficiency of 99.79%, with hydrodynamic diameter of 71.46 ± 1.35 nm and surface charge of -32 mV. AL-Rem demonstrated minimal cytotoxicity in A549 cells and retained monolayer integrity of Calu-3 cells. AL-Rem showed sustained release, with complete drug release obtained within 50 h in simulated lung fluid. Long-term stability indicated >90% drug recovery at 4°C. Desirable aerosol performance, with mass median aerodynamic diameter of 4.56 ± 0.55 and fine particle fraction of 74.40 ± 2.96%, confirmed successful nebulization of AL-Rem. Conclusion: AL-Rem represents an effective alternative for coronavirus disease 2019 treatment.

Formulation and clinical perspectives of inhalation-based nanocarrier delivery: a new archetype in lung cancer treatment

Despite tremendous research in targeted delivery and specific molecular inhibitors (gene delivery), cytotoxic drug delivery through inhalation has been seen as a core part in the treatment of the lung cancer. Inhalation delivery provides a high dose of the drug directly to the lungs without affecting other body organs, increasing the therapeutic ratio. This article reviews the research performed over the last several decades regarding inhalation delivery of various cancer therapeutics for the treatment of lung cancer. Nevertheless, pulmonary administration of nanocarrier-based cancer therapeutics for lung cancer therapy is still in its infancy and faces greater than expected challenges. This article focuses on the current inhalable nanocarrier-based drugs for lung cancer treatment.

Nanoparticle Delivery Systems with Cell-Specific Targeting for Pulmonary Diseases

Respiratory disorders are among the most important medical problems threatening human life. The conventional therapeutics for respiratory disorders are hindered by insufficient drug concentrations at pathological lesions, lack of cell-specific targeting, and various biobarriers in the conducting airways and alveoli. To address these critical issues, various nanoparticle delivery systems have been developed to serve as carriers of specific drugs, DNA expression vectors, and RNAs. The unique properties of nanoparticles, including controlled size and distribution, surface functional groups, high payload capacity, and drug release triggering capabilities, are tailored to specific requirements in drug/gene delivery to overcome major delivery barriers in pulmonary diseases. To avoid off-target effects and improve therapeutic efficacy, nanoparticles with high cell-targeting specificity are essential for successful nanoparticle therapies. Furthermore, low toxicity and high degradability of the nanoparticles are among the most important requirements in the nanoparticle designs. In this review, we provide the most up-to-date research and clinical outcomes in nanoparticle therapies for pulmonary diseases. We also address the current critical issues in key areas of pulmonary cell targeting, biosafety and compatibility, and molecular mechanisms for selective cellular uptake.

Present Situation and Future Progress of Inhaled Lung Cancer Therapy: Necessity of Inhaled Formulations with Drug Delivery Functions

Inhaled lung cancer therapy is promising because of direct and noninvasive drug delivery to the lungs with low potential for severe systemic toxicity. Thus chemotherapeutic drugs have been administered clinically by nebulization of solution or suspension formulations, which demonstrated their limited pulmonary absorption and relatively mild systemic toxicity. In all these clinical trials, however, there was no obviously superior anticancer efficacy in lung cancer patients even at the maximum doses of drugs limited by pulmonary toxicity. Therefore methods that deliver both higher anticancer efficacy and lower pulmonary toxicity are strongly desired. In addition to the worldwide availability of pressured metered dose inhalers (pMDIs) and dry powder inhalers (DPIs) to treat local respiratory diseases, recent innovations in medicines and technologies are encouraging next steps toward effective inhaled lung cancer therapy with new therapeutic or drug delivery concepts. These include the discovery of target cells/molecules and drug candidates for novel cancer therapy, the development of high-performance inhalation devices for effective pulmonary drug delivery, and the establishment of manufacturing technologies for functional nanoparticles/microparticles. This review highlights the present situation and future progress of inhaled drugs for lung cancer therapy, including an overview of available inhalation devices, pharmacokinetics, and outcomes in clinical trials so far and some novel formulation strategies based on drug delivery systems to achieve enhanced anticancer efficacy and attenuated pulmonary toxicity.

On the particle formation of leucine in spray drying of inhalable microparticles

The particle formation of L-leucine, a dispersibility-enhancing amino acid used in the spray drying of inhalable pharmaceutical aerosols, was extensively studied using three experimental methods, and the results were interpreted with the aid of theory. A comparative-kinetics electrodynamic balance was used to study the shell formation behavior in single evaporating microdroplets containing leucine and trehalose. Different concentration thresholds of solidification and shell formation were determined for trehalose and leucine, which were then used in the particle formation model to predict the properties of spray-dried particles. Furthermore, a droplet chain instrument was used to study the particle morphologies and particle densities that were not accessible in the single particle experiments. Lab-scale spray drying was also used to produce powders typical for actual pharmaceutical applications. Raman spectroscopy confirmed that a glass former, such as trehalose, can inhibit the crystallization of leucine. The surface compositions of these spray-dried powders were analyzed via time-of-flight secondary ion mass spectrometry. The leucine surface coverage in a polydisperse powder was determined to be a function of the particle size or the initial droplet diameter of each respective particle. This observation confirms the important role of leucine crystallization kinetics in its shell-forming capabilities. A critical supersaturation ratio of 3.5 was also calculated for leucine, at which it is assumed to instantaneously nucleate out of solution. This ratio was used as the threshold for the initiation of crystallization. Crystallinity predictions for the leucine-trehalose particles based on this supersaturation ratio were in good agreement with the solid-state characterizations obtained by Raman spectroscopy. This study improves the fundamental understanding of the particle formation process of leucine-containing formulations, which can apply to other crystallizing systems and potentially facilitate the rational design of such formulations with reduced experimental effort.

Inhalation Delivery of Host Defense Peptides (HDP) using Nano- Formulation Strategies: A Pragmatic Approach for Therapy of Pulmonary Ailments

Host defense peptides (HDP) are small cationic molecules released by the immune systems of the body, having multidimensional properties including anti-inflammatory, anticancer, antimicrobial and immune-modulatory activity. These molecules gained importance due to their broad-spectrum pharmacological activities, and hence being actively investigated. Presently, respiratory infections represent a major global health problem, and HDP has an enormous potential to be used as an alternative therapeutics against respiratory infections and related inflammatory ailments. Because of their short half-life, protease sensitivity, poor pharmacokinetics, and first-pass metabolism, it is challenging to deliver HDP as such inside the physiological system in a controlled way by conventional delivery systems. Many HDPs are efficacious only at practically high molar-concentrations, which is not convincing for the development of drug regimen due to their intrinsic detrimental effects. To avail the efficacy of HDP in pulmonary diseases, it is essential to deliver an appropriate payload into the targeted site of lungs. Inhalable HDP can be a potentially suitable alternative for various lung disorders including tuberculosis, Cystic fibrosis, Pneumonia, Lung cancer, and others as they are active against resistant microbes and cells and exhibit improved targeting with reduced adverse effects. In this review, we give an overview of the pharmacological efficacy of HDP and deliberate strategies for designing inhalable formulations for enhanced activity and issues related to their clinical implications.

A review on chitosan and its development as pulmonary particulate anti-infective and anti-cancer drug carriers

Chitosan, as a biodegradable and biocompatible polymer, is characterized by anti-microbial and anti-cancer properties. It lately has received a widespread interest for use as the pulmonary particulate backbone materials of drug carrier for the treatment of infectious disease and cancer. The success of chitosan as pulmonary particulate drug carrier is a critical interplay of their mucoadhesive, permeation enhancement and site/cell-specific attributes. In the case of nanocarriers, various microencapsulation and micro-nano blending systems have been devised to equip them with an appropriate aerodynamic character to enable efficient pulmonary aerosolization and inhalation. The late COVID-19 infection is met with acute respiratory distress syndrome and cancer. Chitosan and its derivatives are found useful in combating HCoV and cancer as a function of their molecular weight, substituent type and its degree of substitution. The interest in chitosan is expected to rise in the next decade from the perspectives of drug delivery in combination with its therapeutic performance.

Design of polymeric core-shell carriers for combination therapies

Particle engineering for co-delivery of drugs has the potential to combine multiple drugs with different pharmaceutical mechanisms within the same carrier, increasing the therapeutic efficiency while improving patient compliance. This work proposes a novel approach for producing polymer-polymer core-shell microparticles by multi-step processing of emulsion and spray drying. The particle core was obtained by an oil-in-water emulsion of poly(ε-caprolactone) (PCL) loaded with curcumin (CM), followed by the resuspension in poly(vinyl alcohol) (PVA) containing ciprofloxacin (CPx) forming the shell layer by spray-drying. The obtained core-shell particles showed an average size of 3.8 ± 1.2 μm, which is a suitable size for inhalation therapies. The spatial distribution of the drugs was studied using synchrotron-based macro attenuated total reflection Fourier transform infrared (macro ATR-FTIR) microspectroscopy to map the chemical distribution of the components within the particles and supported the presence of CM and CPx in the core and shell layers, respectively. The formation of the core-shell structure was further supported by the differences in the release profile of CM from these particles, when compared to the release profile observed for the single particle structure (PCL-CM). Both empty and drug-loaded carriers (up to 100 μg.mL^-1) showed no cytotoxic effects on A549 cells while exhibiting the antibacterial activity of CPx against Gram-positive and Gram-negative bacteria. These polymer core-shell microparticles provide a promising route for the combination and sequential drug release therapies, with the potential to be used in inhalation therapies.

Novel Approaches for the Treatment of Pulmonary Tuberculosis

Tuberculosis (TB) is a contagious airborne disease caused by Mycobacterium tuberculosis, which primarily affects human lungs. The progression of drug-susceptible TB to drug-resistant strains, MDR-TB and XDR-TB, has become worldwide challenge in eliminating TB. The limitations of conventional TB treatment including frequent dosing and prolonged treatment, which results in patient’s noncompliance to the treatment because of treatment-related adverse effects. The non-invasive pulmonary drug administration provides the advantages of targeted-site delivery and avoids first-pass metabolism, which reduced the dose requirement and systemic adverse effects of the therapeutics. With the modification of the drugs with advanced carriers, the formulations may possess sustained released property, which helps in reducing the dosing frequency and enhanced patients’ compliances. The dry powder inhaler formulation is easy to handle and storage as it is relatively stable compared to liquids and suspension. This review mainly highlights the aerosolization properties of dry powder inhalable formulations with different anti-TB agents to understand and estimate the deposition manner of the drug in the lungs. Moreover, the safety profile of the novel dry powder inhaler formulations has been discussed. The results of the studies demonstrated that dry powder inhaler formulation has the potential in enhancing treatment efficacy.

Nanoparticles-assisted delivery of antiviral-siRNA as inhalable treatment for human respiratory viruses: A candidate approach against SARS-COV-2

The current pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has challenged healthcare structures across the globe. Although a few therapies are approved by FDA, the search for better treatment options is continuously on rise. Clinical management includes infection prevention and supportive care such as supplemental oxygen and mechanical ventilatory support. Given the urgent nature of the pandemic and the number of companies and researchers developing COVID-19 related therapies, FDA has created an emergency program to move potential treatments with already approved drugs to patients as quickly as possible in parallel to the development of new drugs that must first pass the clinical trials. In this manuscript, we have reviewed the available literature on the use of sequence-specific degradation of viral genome using short-interfering RNA (siRNA) suggesting it as a possible treatment against SARS-CoV-2. Delivery of siRNA can be promoted by the use of FDA approved lipids, polymers or lipid-polymer hybrids. These nanoparticulate systems can be engineered to exhibit increased targetability and formulated as inhalable aerosols.

Targeted drug nanocrystals for pulmonary delivery: a potential strategy for lung cancer therapy

INTRODUCTION

Lung cancer and metastases are major concerns worldwide. Although systemic chemotherapy is the recommended treatment, it is associated with various disadvantages, including nonselective drug distribution and systemic toxicity. In contrast, the pulmonary route ensures the localized delivery of drugs to the lung. Still, the pulmonary route is prone to clearance, limited drug dissolution, and local toxicity to healthy lung cells. Drug nanocrystals provide a potential strategy to enhance the therapeutic efficacy and mitigate the limitations of pulmonary delivery.

AREAS COVERED

The development and potential application of nanocrystals in pulmonary delivery, their role in overcoming associated barriers, and strategies for site-specific and stimuli-responsive pulmonary delivery are outlined. This review also traces different in-vitro pulmonary models for assessments of the performance of drug nanocrystals and nanocrystals loaded carriers in pulmonary delivery.

EXPERT OPINION

Enhanced stability, high aerosolization performance, better particle size distribution, improved penetration, sustained release of the drug, and minimal excipients usage makes drug nanocrystal an ideal candidate for pulmonary delivery. Besides, drug nanocrystals may provide selective cellular internalization with minimum clearance and maximum deposition. Furthermore, surface modified nanocrystals and nanocrystals in nanocarriers can exhibit a more prolonged, and site-specific release of the drug to cancer cells in the lungs.

Development of pharmaceutically scalable inhaled anti-cancer nanotherapy - Repurposing amodiaquine for non-small cell lung cancer (NSCLC)

New drug and dosage form development faces significant challenges, especially in oncology, due to longer development cycle and associated scale-up complexities. Repurposing of existing drugs with potential anti-cancer activity into new therapeutic regimens provides a feasible alternative. In this project, amodiaquine (AQ), an anti-malarial drug, has been explored for its anti-cancer efficacy through formulating inhalable nanoparticulate systems using high-pressure homogenization (HPH) with scale-up feasibility and high reproducibility. A 3² multifactorial design was employed to better understand critical processes (probe homogenization speed while formulating coarse emulsion) and formulation parameters (concentration of cationic polymer in external aqueous phase) so as to ensure product quality with improved anticancer efficacy in non-small cell lung cancer (NSCLC). Optimized AQ loaded nanoparticles (AQ NP) were evaluated for physicochemical properties, stability profile, in-vitro aerosol deposition behavior, cytotoxic potential against NSCLC cells in-vitro and in 3D simulated tumor spheroid model. The highest probe homogenization speed (25,000 rpm) resulted in lower particle size. Incorporation of cationic polymer, polyethylenimine (0.5% w/v) resulted in high drug loading efficiencies at optimal drug quantity of 5 mg. Formulated nanoparticles (liquid state) exhibited an aerodynamic diameter of 4.7 ± 0.1 μm and fine particle fraction of 81.0 ± 9.1%, indicating drug deposition in the respirable airways. Cytotoxicity studies in different NSCLC cell lines revealed significant reduction in IC₅₀ values with AQ-loaded nanoparticles compared to plain drug, along with significant cell migration inhibition (scratch assay) and reduced % colony growth (clonogenic assay) in A549 cells with AQ NP. Moreover, 3D simulated spheroid studies revealed efficacy of nanoparticles in penetration to tumor core, and growth inhibition. AQ's autophagy inhibition ability significantly increased (increased LC3B-II levels) with nanoparticle encapsulation, along with moderate improvement in apoptosis induction (Caspase-3 levels). No impact was observed on HUVEC angiogenesis suggesting alternative anticancer mechanisms. To conclude, amodiaquine can be a promising candidate for repurposing to treat NSCLC while delivering inhalable nanoparticles developed using a scalable HPH process. Despite the involvement of complex parameters, application of DoE has simplified the process of product and process optimization.

Systematic Development and Optimization of Inhalable Pirfenidone Liposomes for Non-Small Cell Lung Cancer Treatment

Non-small cell lung cancer (NSCLC) is a global disorder, treatment options for which remain limited with resistance development by cancer cells and off-target events being major roadblocks for current therapies. The discovery of new drug molecules remains time-consuming, expensive, and prone to failure in safety/efficacy studies. Drug repurposing (i.e., investigating FDA-approved drug molecules for use against new indications) provides an opportunity to shorten the drug development cycle. In this project, we propose to repurpose pirfenidone (PFD), an anti-fibrotic drug, for NSCLC treatment by encapsulation in a cationic liposomal carrier. Liposomal formulations were optimized and evaluated for their physicochemical properties, in-vitro aerosol deposition behavior, cellular internalization capability, and therapeutic potential against NSCLC cell lines in-vitro and ex-vivo. Anti-cancer activity of PFD-loaded liposomes and molecular mechanistic efficacy was determined through colony formation (1.5- to 2-fold reduction in colony growth compared to PFD treatment in H4006, A549 cell lines, respectively), cell migration, apoptosis and angiogenesis assays. Ex-vivo studies using 3D tumor spheroid models revealed superior efficacy of PFD-loaded liposomes against NSCLC, as compared to plain PFD. Hence, the potential of inhalable liposome-loaded pirfenidone in NSCLC treatment has been established in-vitro and ex-vivo, where further studies are required to determine their efficacy through in vivo preclinical studies followed by clinical studies.

siRNA Conjugated Nanoparticles-A Next Generation Strategy to Treat Lung Cancer

Despite major progress in both therapeutic and diagnostic techniques, lung cancer is still considered the leading cause of cancer mortality in the world due to the ineffectiveness of the classical treatments used nowadays. Luckily, the discovery of small interfering RNA (siRNA) planted hope in the hearts of scientists and patients worldwide as a new breakthrough in the world of oncology and a robust tool for finally curing cancer. However, the valuable siRNA must be protected and preserved to ensure the effectiveness of this gene therapy, thus nanoparticles are gaining more attention than previous years as the optimal carriers for this fragile molecule. siRNA-loaded nanoparticles are being extensively investigated to find the appropriate formulation, combination, and delivery route with one objective in mind—successfully overcoming all possible limitations shown in clinical studies and making full use of this novel technique to become the next generation treatment to wipe out many chronic diseases, including cancer. In this review, the benefits of using siRNA and nanoparticles in lung cancer treatment will be globally reviewed before discussing why and how nanoparticles and siRNA can be combined to achieve an efficient treatment of lung cancer for prospective clinical applications.

The Position of Inhaled Chemotherapy in the Care of Patients with Lung Tumors: Clinical Feasibility and Indications According to Recent Pharmaceutical Progresses

Despite new treatment modalities, including targeted therapies and checkpoint inhibitors, cytotoxic chemotherapy remains central in the care of patients with lung tumors. Use of the pulmonary route to deliver chemotherapy has been proved to be feasible and safe in phase I, Ib/IIa and II trials for lung tumors, with the administration of drug doses to the lungs without prior distribution in the organism. The severe systemic toxicities commonly observed with conventional systemic chemotherapy are consequently reduced. However, development has failed in phase II at best. This review first focuses on the causes of failure of inhaled chemotherapy. It then presents new promising technologies able to take up the current challenges. These technologies include the use of a dry powder inhaler or a smart nebulizer with advanced drug formulations such as controlled-release formulations and nanomedicine. Finally, the potential position of inhaled chemotherapy in patient care is discussed and some indications are proposed based on the literature.

Polyethylene glycol-coated porous magnetic nanoparticles for targeted delivery of chemotherapeutics under magnetic hyperthermia condition

PURPOSE

Although magnetite nanoparticles (MNPs) are promising agents for hyperthermia therapy, insufficient drug encapsulation efficacies inhibit their application as nanocarriers in the targeted drug delivery systems. In this study, porous magnetite nanoparticles (PMNPs) were synthesized and coated with a thermosensitive polymeric shell to obtain a synergistic effect of hyperthermia and chemotherapy.

MATERIALS AND METHODS

PMNPs were produced using cetyltrimethyl ammonium bromide template and then coated by a polyethylene glycol layer with molecular weight of 1500 Da (PEG1500) and phase transition temperature of 48 ± 2 °C to endow a thermosensitive behavior. The profile of drug release from the nanostructure was studied at various hyperthermia conditions generated by waterbath, magnetic resonance-guided focused ultrasound (MRgFUS), and alternating magnetic field (AMF). The in vitro cytotoxicity and hyperthermia efficacy of the doxorubicin-loaded nanoparticles (DOX-PEG1500-PMNPs) were assessed using human lung adenocarcinoma (A549) cells.

RESULTS

Heat treatment of DOX-PEG1500-PMNPs containing 235 ± 26 mg·g^-1 DOX at 48 °C by waterbath, MRgFUS, and AMF, respectively led to 71 ± 4%, 48 ± 3%, and 74 ± 5% drug release. Hyperthermia treatment of the A549 cells using DOX-PEG1500-PMNPs led to 77% decrease in the cell viability due to the synergistic effects of magnetic hyperthermia and chemotherapy.

CONCLUSION

The large pores generated in the PMNPs structure could provide a sufficient space for encapsulation of the chemotherapeutics as well as fast drug encapsulation and release kinetics, which together with thermosensitive characteristics of the PEG1500 shell, make DOX-PEG1500-PMNPs promising adjuvants to the magnetic hyperthermia modality.