Impact of atomization technique on the stability and transport efficiency of nebulized liposomes harboring different surface characteristics

Nebulization and In Vitro Upper Airway Deposition of Liposomal Carrier Systems

Liposomal carrier systems have emerged as a promising technology for pulmonary drug delivery. This study focuses on two selected liposomal systems, namely, dipalmitoylphosphatidylcholine stabilized by phosphatidic acid and cholesterol (DPPC-PA-Chol) and dipalmitoylphosphatidylcholine stabilized by polyethylene glycol and cholesterol (DPPC-PEG-Chol). First, the research investigates the stability of these liposomal systems during the atomization process using different kinds of nebulizers (air-jet, vibrating mesh, and ultrasonic). The study further explores the aerodynamic particle size distribution of the aerosol generated by the nebulizers. The nebulizer that demonstrated optimal stability and particle size was selected for more detailed investigation, including Andersen cascade impactor measurements, an assessment of the influence of flow rate and breathing profiles on aerosol particle size, and an in vitro deposition study on a realistic replica of the upper airways. The most suitable combination of a nebulizer and liposomal system was DPPC-PA-Chol nebulized by a Pari LC Sprint Star in terms of stability and particle size. The influence of the inspiration flow rate on the particle size was not very strong but was not negligible either (decrease of Dv50 by 1.34 μm with the flow rate increase from 8 to 60 L/min). A similar effect was observed for realistic transient inhalation. According to the in vitro deposition measurement, approximately 90% and 70% of the aerosol penetrated downstream of the trachea using the stationary flow rate and the realistic breathing profile, respectively. These data provide an image of the potential applicability of liposomal carrier systems for nebulizer therapy. Regional lung drug deposition is patient-specific; therefore, deposition results might vary for different airway geometries. However, deposition measurement with realistic boundary conditions (airway geometry, breathing profile) brings a more realistic image of the drug delivery by the selected technology. Our results show how much data from cascade impactor testing or estimates from the fine fraction concept differ from those of a more realistic case.

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.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Inhaled lipid nanocarriers for pulmonary delivery of glucocorticoids: previous strategies, recent advances and key factors description

In view of the strong anti-inflammatory activity of glucocorticoids (GC) they are used in the treatment of almost all inflammatory lung diseases. In particular, inhaled GC (IGC) allow high drug concentrations to be deposited in the lung and may reduce the incidence of adverse effects associated with systemic administration. However, rapid absorption through the highly absorbent surface of the lung epithelium may limit the success of localized therapy. Therefore, inhalation of GC incorporated into nanocarriers is a possible approach to overcome this drawback. In particular, lipid nanocarriers, which showed high pulmonary biocompatibility and are well known in the pharmaceutical industry, have the best prospects for pulmonary delivery of GC by inhalation. This review provides an overview of the pre-clinical applications of inhaled GC-lipid nanocarriers based on several key factors that will determine the efficiency of local pulmonary GC delivery: 1) stability to nebulization, 2) deposition profile in the lungs, 3) mucociliary clearance, 4) selective accumulation in target cells, 5) residence time in the lung and systemic absorption and 6) biocompatibility. Finally, novel preclinical pulmonary models for inflammatory lung diseases are also discussed.

An Inhalable Hybrid Biomimetic Nanoplatform for Sequential Drug Release and Remodeling Lung Immune Homeostasis in Acute Lung Injury Treatment

Interactions of lung macrophages and recruited neutrophils with the lung microenvironment continuously aggravate the dysregulation of lung inflammation in the pathogenesis of acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Either modulating macrophages or destroying neutrophil counts cannot guarantee a satisfactory outcome in ARDS treatment. Aimed at inhibiting the coordinated action of neutrophils and macrophages and modulating the hyper-inflammatory condition, an inhalable biomimetic sequential drug-releasing nanoplatform was developed for the combinatorial treatment of ALI. The nanoplatform (termed D-SEL) was made by conjugating DNase I, as outer cleavable arms, to a serum exosomal and liposomal hybrid nanocarrier (termed SEL) via a matrix metalloproteinase 9 (MMP-9)-cleavable peptide and then encapsulating methylprednisolone sodium succinate (MPS). In lipopolysaccharide (LPS) induced ALI in mice, the MPS/D-SEL moved through muco-obstructive airways and was retained in the alveoli for over 24 h postinhalation. DNase I was then released from the nanocarrier first after responding to MMP-9, resulting in inner SEL core exposure, which precisely delivered MPS into macrophages for promoting M2 macrophage polarization. Local and sustained DNase I release degraded dysregulated neutrophil extracellular traps (NETs) and suppressed neutrophil activation and the mucus plugging microenvironment, which in turn amplified M2 macrophage polarization efficiency. Such dual-stage drug release behavior facilitated down-regulation of pro-inflammatory cytokines in the lung but anti-inflammatory cytokine production through remodeling lung immune homeostasis, ultimately promoting lung tissue repair. This work presents a versatile hybrid biomimetic nanoplatform for the local pulmonary delivery of dual-drug therapeutics and displays potential in the treatment of acute inflammation.

Liposomal form of erlotinib for local inhalation administration and efficiency of its transport to the lungs

This contribution is focused on the preparation of a liposomal drug delivery system of erlotinib resisting the nebulization process that could be used for local treatment of non-small-cell lung cancer. Liposomes with different compositions were formulated to reveal their influence on the encapsulation efficiency of erlotinib. An encapsulation efficiency higher than 98 % was achieved for all vesicles containing phosphatidic acid (d ≈ 100 nm, ζ = - 43 mV) even in the presence of polyethylene glycol (d ≈ 150 nm, ζ = - 17 mV) which decreased this value in all other formulas. The three most promising formulations were nebulized by two air-jet and two vibrating mesh nebulizers, and the aerosol deposition in lungs was calculated by tools of computational fluid and particle mechanics. According to the numerical simulations and measurements of liposomal stability, air-jet nebulizers generated larger portion of the aerosol able to penetrate deeper into the lungs, but the delivery is likely to be more efficient when the formulation is administered by Aerogen Solo vibrating mesh nebulizer because of a higher portion of intact vesicles after the nebulization. The leakage of encapsulated drug from liposomes nebulized by this nebulizer was lower than 2 % for all chosen vesicles.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Multifunctional Lipid-Based Nanoparticles for Codelivery of Anticancer Drugs and siRNA for Treatment of Non-Small Cell Lung Cancer with Different Level of Resistance and EGFR Mutations

Resistance to chemotherapy, enhanced proliferation, invasion, angiogenesis, and metastasis (RPIAM) represent major obstacles that limit the efficacy of cancer treatment especially in advanced stages of cancer. Overcoming or suppressing RPIAM can dramatically improve the treatment outcome. Non-small cell lung cancer (NSCLC) is frequently diagnosed in an advanced stage and often possesses intrinsic resistance to chemotherapy accompanied by the fast development of acquired resistance during the treatment. Oncogenic receptor tyrosine kinases (TKs), specifically epidermal growth factor (EGF) TKs, play an important role in the activation of MAPK/PI3K/Akt/STAT pathways, finally leading to the development of RPIAM. However, the suppression of EGF-TK by different drugs is limited by various defensive mechanisms and mutations. In order to effectively prevent the development of RPIAM in NSCLC, we formulated and tested a multicomponent and multifunctional cancer targeted delivery system containing Nanostructured Lipid Carriers (NLCs) as vehicles, luteinizing hormone release hormone (LHRH) as a cancer targeting moiety, EFG-TK inhibitor gefitinib and/or paclitaxel as anticancer drug(s), siRNA targeted to EGF receptor (EGFR) mRNA as a suppressor of EGF receptors, and an imaging agent (rhodamine) for the visualization of cancer cells. Experimental data obtained show that this complex delivery system possesses significantly enhanced anticancer activity that cannot be achieved by individual components applied separately.

Influence of liposomes composition on their stability during the nebulization process by vibrating mesh nebulizer

In this study, three different molecules (cholesterol, phosphatidic acid, and polyethylene glycol) were used for the stabilization of liposomes during the nebulization process. The purpose of this article is to answer the question of whether the change in the composition of liposomes affected the parameters of generated aerosol and whether the nebulization process affected observed properties of liposomes. Firstly, liposomes with different composition were prepared and their properties were checked by dynamic and electrophoretic light scattering. The membrane properties were measured by fluorescence spectroscopy - especially generalized polarization (Laurdan) and anisotropy (Diphenylhexatriene). The same characteristic of liposomes was measured after the nebulization by vibrating mesh nebulizer. Cholesterol was capable of liposome stabilization because of increased membrane fluidity. The membrane properties of the outer and inner parts were not influenced by the nebulization process. Electrostatic stabilization was successful for the lowest concentration of phosphatidic acid, but after the nebulization process the hydration of the membrane outer part was changed. Higher amount of PEG needs to be added for successful steric stabilization. The nebulization process of the two lowest concentrations of PEG slightly influenced immobilized water and the rigidity of inner part of the membrane (especially around the phase transition temperature).

siRNA Therapeutics against Respiratory Viral Infections-What Have We Learned for Potential COVID-19 Therapies?

Acute viral respiratory tract infections (AVRIs) are a major burden on human health and global economy and amongst the top five causes of death worldwide resulting in an estimated 3.9 million lives lost every year. In addition, new emerging respiratory viruses regularly cause outbreaks such as SARS-CoV-1 in 2003, the "Swine flu" in 2009, or most importantly the ongoing SARS-CoV-2 pandemic, which intensely impact global health, social life, and economy. Despite the prevalence of AVRIs and an urgent need, no vaccines-except for influenza-or effective treatments were available at the beginning of the COVID-19 pandemic. However, the innate RNAi pathway offers the ability to develop nucleic acid-based antiviral drugs. siRNA sequences against conserved, essential regions of the viral genome can prevent viral replication. In addition, viral infection can be averted prophylactically by silencing host genes essential for host-viral interactions. Unfortunately, delivering siRNAs to their target cells and intracellular site of action remains the principle hurdle toward their therapeutic use. Currently, siRNA formulations and chemical modifications are evaluated for their delivery. This progress report discusses the selection of antiviral siRNA sequences, delivery techniques to the infection sites, and provides an overview of antiviral siRNAs against respiratory viruses.

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.

Liquid–Solid Core-Shell Microcapsules of Calcium Carbonate Coated Emulsions and Liposomes

Micron-sized core-shell particles consisting of a calcium carbonate (CaCO3) mineral shell and a fluidic core were generated using a biomimetic approach, for the purpose of use as biodegradable microcapsules for release of active agents. Dinoflagellate cysts, unicellular organisms which deposit a protective hard mineral shell around their soft and fluidic cellular interior, served as our inspiration. Using the biomimetic polymer-induced liquid-precursor (PILP) mineralization process, calcium carbonate coatings were deposited on charged emulsion droplets and liposomes. Light microscopy, scanning electron microscopy, polarized light microscopy, X-ray diffraction, and confocal fluorescence microscopy were used to demonstrate that smooth CaCO3 mineral coatings can be deposited onto the high curvature surfaces of emulsions and liposomes to yield micron-sized microcapsules for the effective entrapment of both hydrophobic and hydrophilic active agents. These biodegradable and biocompatible CaCO3 microcapsules are novel systems for producing a powdered form of fluid-containing capsules for storage and transport of pharma/chemical agents. They may be used in lieu of, or in conjunction with, existing microcapsule delivery approaches, as well as providing a convenient foundation for which polymeric coatings could be further applied, allowing for more complex targeting and/or chemical-release control.

Pharmacokinetic Research Progress of Anti-tumor Drugs Targeting for Pulmonary Administration

BACKGROUND

Cancer is a major problem that threatens human survival and has a high mortality rate. The traditional chemotherapy methods are mainly intravenous injection and oral administration, but have obvious toxic and side effects. Anti-tumor drugs for pulmonary administration can enhance drug targeting, increase local drug concentration, and reduce the damage to systemic organs, especially for the treatment of lung cancer.

METHODS

The articles on the pharmacokinetics of anti-tumor drugs targeting pulmonary administration were retrieved from the Pub Med database. This article mainly took lung cancer as an example and summarized the pharmacokinetic characteristics of anti-tumor drugs targeting for pulmonary administration contained in nanoparticles, dendrimers, liposomes and micelles.

RESULTS

The review shows that the pharmacokinetics process of pulmonary administration is associated with a drug carrier by increasing the deposition and release of drugs in the lung, and retarding the lung clearance rate. Among them, the surface of dendrimers could be readily modified, and polymer micelles have favorable loading efficiency. In the case of inhalation administration, liposomes exhibit more excellent lung retention properties compared to other non-lipid carriers. Therefore, the appropriate drug carrier is instrumental to increase the curative effect of anti-tumor drugs and reduce the toxic effect on surrounding healthy tissues or organs.

CONCLUSION

In the process of pulmonary administration, the carrier-embedded antitumor drugs have the characteristics of targeted and sustained release compared with non-packaging drugs, which provides a theoretical basis for the clinical rational formulation of chemotherapy regimens. However, there is currently a lack of comparative research between drug packaging materials, and more importantly, the development of safe and effective anti-tumor drugs targeting for pulmonary administration requires more data.

Inhaled Liposomal Antimicrobial Delivery in Lung Infections

The management of difficult-to-treat acute and chronic respiratory infections (infections in cystic fibrosis, non-cystic fibrosis bronchiectasis, immunocompromised and mechanically ventilated patients) and difficult-to-treat pathogens (including multidrug-resistant strains) has become a challenge in clinical practice. The arsenal of conventional antibiotic drugs can be limited by tissue penetration, toxicities, or increasing antibiotic resistance. Inhaled antimicrobials are an interesting therapeutic approach for optimizing the management of respiratory infections. Due to extensive developments in liposome technology, a number of inhaled liposome-based antibiotic and antifungal formulations are available for human use and many products are undergoing clinical trials. Liposomes are biocompatible, biodegradable, and nontoxic vesicles able to encapsulate and carry antimicrobials, enhancing the therapeutic index of various agents and retention at the desired target within the lung. Liposomes reduce drug toxicity and improve tolerability, leading to better compliance and to decreased respiratory side effects. The aim of this article was to provide an up-to-date overview of nebulized liposomal antimicrobials for lung infections (with a special focus on liposomal amikacin, tobramycin, ciprofloxacin, and amphotericin B for inhalation), discussing the feasibility and therapeutic potential of these new strategies of preventing and treating bacteria, mycobacterial and fungal infections.

Airway epithelial-targeted nanoparticles for asthma therapy

Asthma is a common chronic inflammatory disease associated with intermittent airflow obstruction caused by airway inflammation, mucus overproduction, and bronchial hyperresponsiveness. Despite current treatment and management options, a large number of patients with asthma still have poorly controlled disease and are susceptible to acute exacerbations, usually caused by a respiratory virus infection. As a result, there remains a need for novel therapies to achieve better control and prevent/treat exacerbations. Nanoparticles (NPs), including extracellular vesicles (EV) and their synthetic counterparts, have been developed for drug delivery in respiratory diseases. In the case of asthma, where airway epithelium dysfunction, including dysregulated differentiation of epithelial cells, impaired barrier, and immune response, is a driver of disease, targeting airway epithelial cells with NPs may offer opportunities to repair or reverse these dysfunctions with therapeutic interventions. EVs possess multiple advantages for airway epithelial targeting, such as their natural intrinsic cell-targeting properties and low immunogenicity. Synthetic NPs can be coated with muco-inert polymers to overcome biological barriers such as mucus and the phagocytic response of immune cells. Targeting ligands could be also added to enhance targeting specificity to epithelial cells. The review presents current understanding and advances in NP-mediated drug delivery to airway epithelium for asthma therapy. Future perspectives in this therapeutic strategy will also be discussed, including the development of novel formulations and physiologically relevant preclinical models.

Inhalable nanotherapeutics to improve treatment efficacy for common lung diseases

Respiratory illnesses are prevalent around the world, and inhalation-based therapies provide an attractive, noninvasive means of directly delivering therapeutic agents to their site of action to improve treatment efficacy and limit adverse systemic side effects. Recent trends in medicine and nanoscience have prompted the development of inhalable nanomedicines to further enhance effectiveness, patient compliance, and quality of life for people suffering from lung cancer, chronic pulmonary diseases, and tuberculosis. Herein, we discuss recent advancements in the development of inhalable nanomaterial-based drug delivery systems and analyze several representative systems to illustrate their key design principles that can translate to improved therapeutic efficacy for prevalent respiratory diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease.

Sildenafil Citrate Liposomes for Pulmonary Delivery by Ultrasonic Nebulization

Technological advances in lipid vesicles facilitate optimization of their properties to achieve therapeutic goals and promote alternative drug administration routes. Sildenafil citrate (SC) is orally administered for the treatment of pulmonary hypertension, but local release would be advantageous in terms of efficacy and safety. In the present study, liposomes from egg phosphatidylcholine and cholesterol loaded with SC, with and without d-α-tocopheryl polyethylene glycol 1000 succinate (Vit E TPGS), were prepared by sonication of the components. A transmembrane pH gradient was applied for active loading of liposomes, and the size, zeta potential, and entrapment efficiency (EE%) were determined. The liposomes were lyophilized and then nebulized. The nebulized samples were collected and the EE% was determined. The transmembrane pH gradient produced a significant increase in the EE% (from 17.68 ± 4.25% to 89.77 ± 7.64%) and, after lyophilization, the EE% remained the same as that of the originals, but the size and zeta potential were modified. EE% of liposomes decreased upon nebulization, particularly for those with Vit E TPGS. Thus, the additives used for lyoprotection reduced the impact of nebulization. Additional studies are essential, but according to these results, SC-loaded liposomes can be considered as suitable and safe carriers for the local release of sildenafil in the pulmonary system.

Preparation of drug-loaded small unilamellar liposomes and evaluation of their potential for the treatment of chronic respiratory diseases

The aim of the present investigation was to evaluate the influence of liposome formulation on the ability of vesicles to penetrate a pathological mucus model obtained from COPD affected patients in order to assess the potential of such vesicles for the treatment of chronic respiratory diseases by inhalation. Therefore, Small Unilamellar Liposomes (PLAIN-LIPOSOMEs), Pluronic® F127-surface modified liposomes (PF-LIPOSOMEs) and PEG 2000PE-surface modified liposomes (PEG-LIPOSOMEs) were prepared using the micelle-to-vesicle transition (MVT) method and beclomethasone dipropionate (BDP) as model drug. The obtained liposomes showed diameters in the range of 40-65 nm, PDI values between 0.25 and 0.30 and surface electric charge essentially close to zero. The encapsulation efficiency was found to be dependent on the BDP/lipid ratio used and, furthermore, BDP-loaded liposomes were stable in size both at 37 °C and at 4 °C. All liposomes were not cytotoxic on H441 cell line as assessed by the MTT assay. The liposome uptake was evaluated through a cytofluorimetric assay that showed a non-significant reduction in the internalization of PEG-LIPOSOMEs as compared with PLAIN-LIPOSOMEs. The penetration studies of mucus from COPD patients showed that the PEG-LIPOSOMEs were the most mucus-penetrating vesicles after 27 h. In addition, PEG- and PF-LIPOSOMEs did not cause any effect on bronchoalveolar lavage fluid proteins after aerosol administration in the mouse. The results highlight that PEG-LIPOSOMEs show the most interesting features in terms of penetration through the pathologic sputum, uptake by airway epithelial cells and safety profile.

A chitosan-coated liposome encapsulating antibacterial peptide, Apep10: characterisation, triggered-release effects and antilisterial activity in thaw water of frozen chicken

Contamination of Listeria monocytogenes in food and their processing environment is a focus of attention in the food industry. To achieve the controlled release of antibacterial agents to a food processing environment contaminated by L. monocytogenes, chitosan-stabilised liposomes encapsulating Apep10 (GLARCLAGTL), an antibacterial peptide derived from boiled-dried anchovies, were prepared by utilising listeria toxins to activate the peptide release. Characteristics including the particle size, polydispersity index (PDI), encapsulation efficiency (EE), and morphology of the chitosan-coated Apep10 liposomes were investigated. The chitosan liposomes were more stable than their uncoated counterparts, which indicated that the coating of chitosan on the surface of the liposomes inhibited undesirable vesicle fusion and payload release during storage. However, once the chitosan-stabilised liposomes encountered L. monocytogenes, which secretes pore-forming toxins, the encapsulated antibacterial peptide was released and it exerted antimicrobial effects on the strain. The results of time-kill inhibition, scanning electron microscopy (SEM), crystal violet staining and confocal laser scanning microscopy (CLSM) images demonstrated that these liposomes have favourable antibacterial and anti-biofilm activities against L. monocytogenes in the thaw water of frozen chicken. This bacterial toxin-enabled release of the encapsulated antibacterial peptide from chitosan-coated liposomes provides an effective approach for the control of listerial contamination. This technique can be broadly applied to treat contamination by a variety of pathogens that secrete pore-forming toxins.

Generation of High Concentrations of Respirable Solid-Phase Aerosols from Viscous Fluids

High outputs of respirable solid-phase aerosols were generated from viscous solutions or suspensions of low and high molecular weight polyvinylprrolidone (PVP) solutions, 10% (w/v) albumin and, gamma-globulin solutions as well as 10.3% (w/v) surfactant suspensions. A central fluid flow was aerosolized by coaxial converging compressed air. The water was evaporated from the droplets using warm dilution air and infrared radiation. The resulting aerosol particles were concentrated using a virtual impactor. The aerosols were generated at fluid flow rates between 1 and 3 ml/min and delivered at a flow rate of 44 l/min as 2.6 - 3.6 μm MMAD aerosols with geometric standard deviations between 1.5 and 2. Increases in viscosity over the range of 4 to 39 cSt caused a modest increase in MMAD. Increases in aerosol exit orifice diameter was associated with a decrease in aerosol diameter. Increases in compressed air pressure caused a decrease in aerosol diameter. Increases in fluid flow rate resulted modest increases in MMAD together with proportional increases in output mass. Aerosolizing 10% 8 kDa PVP at 3 ml/min resulted in the delivery of 193 mg/min of PVP at 64% efficiency enabling 1.2 g to be collected in 7 min. Aerosolizing 10.3% surfactant suspensions at 3 ml/min resulted in the delivery of up to 163 mg/min with 59% efficiency. The surface tension of the surfactant was not changed by these processes. SEM showed dimpled particles of PVP, albumin and gamma globulin indicating that their aerodynamic diameter was less than their morphometric diameter.

Advanced Therapeutic Strategies for Chronic Lung Disease Using Nanoparticle-Based Drug Delivery

Chronic lung diseases include a variety of obstinate and fatal diseases, including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), idiopathic pulmonary fibrosis (IPF), and lung cancers. Pharmacotherapy is important for the treatment of chronic lung diseases, and current progress in nanoparticles offers great potential as an advanced strategy for drug delivery. Based on their biophysical properties, nanoparticles have shown improved pharmacokinetics of therapeutics and controlled drug delivery, gaining great attention. Herein, we will review the nanoparticle-based drug delivery system for the treatment of chronic lung diseases. Various types of nanoparticles will be introduced, and recent innovative efforts to utilize the nanoparticles as novel drug carriers for the effective treatment of chronic lung diseases will also be discussed.

Surviving nebulization-induced stress: dexamethasone in pH-sensitive archaeosomes

Aim: To increase the subcellular delivery of dexamethasone phosphate (DP) and stability to nebulization stress, pH-sensitive nanoliposomes (LpH) exhibiting archaeolipids, acting as ligands for scavenger receptors (pH-sensitive archaeosomes [ApH]), were prepared. Materials & methods: The anti-inflammatory effect of 0.18 mg DP/mg total lipid, 100–150 nm DP-containing ApH (dioleylphosphatidylethanolamine: Halorubrum tebenquichense total polar archaeolipids:cholesteryl hemisuccinate 4.2:2.8:3 w:w) was tested on different cell lines. Size and HPTS retention of ApH and conventional LpH (dioleylphosphatidylethanolamine:cholesteryl hemisuccinate 7:3 w:w) before and after nebulization were determined. Results & conclusion: DP-ApH suppressed IL-6 and TNF-α on phagocytic cells. Nebulized after 6-month storage, LpH increased size and completely lost its HPTS while ApH3 conserved size and polydispersity, fully retaining its original HPTS content.

The function and performance of aqueous aerosol devices for inhalation therapy

OBJECTIVES

In this review paper, we explore the interaction between the functioning mechanism of different nebulizers and the physicochemical properties of the formulations for several types of devices, namely jet, ultrasonic and vibrating-mesh nebulizers; colliding and extruded jets; electrohydrodynamic mechanism; surface acoustic wave microfluidic atomization; and capillary aerosol generation.

KEY FINDINGS

Nebulization is the transformation of bulk liquids into droplets. For inhalation therapy, nebulizers are widely used to aerosolize aqueous systems, such as solutions and suspensions. The interaction between the functioning mechanism of different nebulizers and the physicochemical properties of the formulations plays a significant role in the performance of aerosol generation appropriate for pulmonary delivery. Certain types of nebulizers have consistently presented temperature increase during the nebulization event. Therefore, careful consideration should be given when evaluating thermo-labile drugs, such as protein therapeutics. We also present the general approaches for characterization of nebulizer formulations.

SUMMARY

In conclusion, the interplay between the dosage form (i.e. aqueous systems) and the specific type of device for aerosol generation determines the effectiveness of drug delivery in nebulization therapies, thus requiring extensive understanding and characterization.

Liposome Delivery Systems for Inhalation: A Critical Review Highlighting Formulation Issues and Anticancer Applications

This is a critical review on research conducted in the field of pulmonary delivery of liposomes. Issues relating to the mechanism of nebulisation and liposome composition were appraised and correlated with literature reports of liposome formulations used in clinical trials to understand the role of liposome size and composition on therapeutic outcome. A major highlight was liposome inhalation for the treatment of lung cancers. Many in vivo studies that explored the potential of liposomes as anticancer carrier systems were evaluated, including animal studies and clinical trials. Liposomes can entrap anticancer drugs and localise their action in the lung following pulmonary delivery. The safety of inhaled liposomes incorporating anticancer drugs depends on the anticancer agent used and the amount of drug delivered to the target cancer in the lung. The difficulty of efficient targeting of liposomal anticancer aerosols to the cancerous tissues within the lung may result in low doses reaching the target site. Overall, following the success of liposomes as inhalable carriers in the treatment of lung infections, it is expected that more focus from research and development will be given to designing inhalable liposome carriers for the treatment of other lung diseases, including pulmonary cancers. The successful development of anticancer liposomes for inhalation may depend on the future development of effective aerosolisation devices and better targeted liposomes to maximise the benefit of therapy and reduce the potential for local and systemic adverse effects.

Nanotechnology approaches for inhalation treatment of lung diseases

Local administration of therapeutics by inhalation for treatment of lung diseases has the ability to deliver drugs, nucleic acids and peptides specifically to the site of their action and therefore enhance the efficacy of the treatment, limit the penetration of nebulized therapeutic agent(s) into the bloodstream and consequently decrease adverse systemic side effects of the treatment. Nanotechnology allows for a further enhancement of the treatment efficiency. The present review analyzes modern therapeutic approaches of inhaled nanoscale-based pharmaceutics for the detection and treatment of various lung diseases.