Bridging the Gap Between Science and Clinical Efficacy: Physiology, Imaging, and Modeling of Aerosols in the Lung

The role of extracellular vesicles in non-small-cell lung cancer, the unknowns, and how new approach methodologies can support new knowledge generation in the field

Extracellular vesicles (EVs) are nanosized particles released from most human cell types that contain a variety of cargos responsible for mediating cell-to-cell and organ-to-organ communications. Current knowledge demonstrates that EVs also play critical roles in many aspects of the progression of Non-Small-Cell Lung Cancer (NSCLC). Their roles range from increasing proliferative signalling to inhibiting apoptosis, promoting cancer metastasis, and modulating the tumour microenvironment to support cancer development. However, due to the limited availability of patient samples, intrinsic inter-species differences between human and animal EV biology, and the complex nature of EV interactions in vivo, where multiple cell types are present and several events occur simultaneously, the use of conventional preclinical and clinical models has significantly hindered reaching conclusive results. This review discusses the biological roles that EVs are currently known to play in NSCLC and identifies specific challenges in advancing today's knowledge. It also describes the NSCLC models that have been used to define currently-known EV functions, the limitations associated with their use in this field, and how New Approach Methodologies (NAMs), such as microfluidic platforms, organoids, and spheroids, can be used to overcome these limitations, effectively supporting future exciting discoveries in the NSCLC field and the potential clinical exploitation of EVs.

In Vitro Drug Delivery of a Fixed-Dose Combination of Fluticasone Furoate/Umeclidinium/Vilanterol from a Dry Powder Inhaler

Background: Dry powder inhalers (DPIs) require patients to impart sufficient energy through inhalation to ensure adequate dose emission, medication deaggregation, and resultant particle sizes suitable for lung deposition. There is an ongoing debate regarding the level of inspiratory effort, and therefore inspiratory flow rate, needed for optimal dose delivery from DPIs. Materials and Methods: The delivered dose (DD) and fine particle fraction (FPF) for each component of fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) 100/62.5/25 μg and FF/UMEC/VI 200/62.5/25 μg ELLIPTA DPIs were assessed at flow rates of 30, 60, and 90 L/min. Electronic lung (eLung) (eLung; an electronic breathing simulator) assessments were conducted to replicate inhalation profiles representing a wide range of inhalation parameters and inhaled volumes achieved by patients with chronic obstructive pulmonary disease (COPD) or asthma of all severity levels. Timing and duration of dose emission were assessed using a particle detector located at the entrance of an anatomical throat cast attached to the eLung. Results: During DD assessment, a mean of >80% of the nominal blister content (nbc) was emitted from the ELLIPTA DPI at all flow rates. In Next Generation Impactor assessments, the observed mean DD across flow rates for FF/UMEC/VI 100/62.5/25 μg ranged from 85.9% to 97.0% of nbc and 84.0% to 93.5% for FF/UMEC/VI 200/62.5/25 μg. In eLung assessments, 82.8% to 95.5% of nbc was delivered across the PIF range, 43.5 to 129.9 L/min (COPD), and 85.1% to 92.3% across the PIF range, 67.4 to 129.9 L/min (asthma). The FPF (mass <5 μm; % nbc) for each component was comparable across all flow rates and inhalation profiles. Dose emission timings indicated that near-complete dose emission occurs before reaching PIF. Conclusions: Dose delivery assessments across all flow rates and inhalation profiles indicate that patients with all severity levels of COPD or asthma can achieve the required inspiratory effort for efficient delivery of all components of FF/UMEC/VI from the ELLIPTA DPI. Dose emission profiles suggest rapid and near-complete dose delivery from the ELLIPTA DPI before reaching PIF.

Not all nebulizers are created equal: Considerations in choosing a nebulizer for aerosol delivery during mechanical ventilation

INTRODUCTION

Aerosol therapy is commonly prescribed in the mechanically ventilated patient. Jet nebulizers (JN) and vibrating mesh nebulizers (VMN) are the most common nebulizer types, however, despite VMN's well established superior performance, JN use remains the most commonly used of the two. In this review, we describe the key differentiators between nebulizer types and how considered selection of nebulizer type may enable successful therapy and the optimization of drug/device combination products.

AREAS COVERED

Following a review of the published literature up to February 2023, the current state of the art in relation to JN and VMN is discussed under the headings of in vitro performance of nebulizers during mechanical ventilation, respective compatibility with formulations for inhalation, clinical trials making use of VMN during mechanical ventilation, distribution of nebulized aerosol throughout the lung, measuring the respective performance of nebulizers in the patient and non-drug delivery considerations in nebulizer choice.

EXPERT OPINION

Whether for standard care, or the development of drug/device combination products, the choice of nebulizer type should not be made without consideration of the unique needs of the combination of each of drug, disease and patient types, as well as target site for deposition, and healthcare professional and patient safety.

Aerosolised micro and nanoparticle: formulation and delivery method for lung imaging

Purpose

The application of contrast and tracing agents is essential for lung imaging, as indicated by the wide use in recent decades and the discovery of various new contrast and tracing agents. Different aerosol production and pulmonary administration methods have been developed to improve lung imaging quality. This review details and discusses the ideal characteristics of aerosol administered via pulmonary delivery for lung imaging and the methods for the production and pulmonary administration of dry or liquid aerosol.

Methods

We explored several databases, including PubMed, Scopus, and Google Scholar, while preparing this review to discover and obtain the abstracts, reports, review articles, and research papers related to aerosol delivery for lung imaging and the formulation and pulmonary delivery method of dry and liquid aerosol. The search terms used were "dry aerosol delivery", "liquid aerosol delivery", "MRI for lung imaging", "CT scan for lung imaging", "SPECT for lung imaging", "PET for lung imaging", "magnetic particle imaging", "dry powder inhalation", "nebuliser", and "pressurised metered-dose inhaler".

Results

Through the literature review, we found that the critical considerations in aerosol delivery for lung imaging are appropriate lung deposition of inhaled aerosol and avoiding toxicity. The important tracing agent was also found to be Technetium-99m (^99mTc), Gallium-68 (⁶⁸Ga) and superparamagnetic iron oxide nanoparticle (SPION), while the essential contrast agents are gold, iodine, silver gadolinium, iron and manganese-based particles. The pulmonary delivery of such tracing and contrast agents can be performed using dry formulation (graphite ablation, spark ignition and spray dried powder) and liquid aerosol (nebulisation, pressurised metered-dose inhalation and air spray).

Conclusion

A dual-imaging modality with the combination of different tracing or contrast agents is a future development of aerosolised micro and nanoparticles for lung imaging to improve diagnosis success.

Graphical abstract

Real-Time Measurement of Cell Mechanics as a Clinically Relevant Readout of an In Vitro Lung Fibrosis Model Established on a Bioinspired Basement Membrane

Lung fibrosis, one of the major post-COVID complications, is a progressive and ultimately fatal disease without a cure. Here, an organ- and disease-specific in vitro mini-lung fibrosis model equipped with noninvasive real-time monitoring of cell mechanics is introduced as a functional readout. To establish an intricate multiculture model under physiologic conditions, a biomimetic ultrathin basement (biphasic elastic thin for air-liquid culture conditions, BETA) membrane (<1 µm) is developed with unique properties, including biocompatibility, permeability, and high elasticity (<10 kPa) for cell culturing under air-liquid interface and cyclic mechanical stretch conditions. The human-based triple coculture fibrosis model, which includes epithelial and endothelial cell lines combined with primary fibroblasts from idiopathic pulmonary fibrosis patients established on the BETA membrane, is integrated into a millifluidic bioreactor system (cyclic in vitro cell-stretch, CIVIC) with dose-controlled aerosolized drug delivery, mimicking inhalation therapy. The real-time measurement of cell/tissue stiffness (and compliance) is shown as a clinical biomarker of the progression/attenuation of fibrosis upon drug treatment, which is confirmed for inhaled Nintedanib-an antifibrosis drug. The mini-lung fibrosis model allows the combined longitudinal testing of pharmacodynamics and pharmacokinetics of drugs, which is expected to enhance the predictive capacity of preclinical models and hence facilitate the development of approved therapies for lung fibrosis.

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.

Effect of patient inhalation profile and airway structure on drug deposition in image-based models with particle-particle interactions

For many of the one billion sufferers of respiratory diseases worldwide, managing their disease with inhalers improves their ability to breathe. Poor disease management and rising pollution can trigger exacerbations that require urgent relief. Higher drug deposition in the throat instead of the lungs limits the impact on patient symptoms. To optimise delivery to the lung, patient-specific computational studies of aerosol inhalation can be used. However in many studies, inhalation modelling does not represent situations when the breathing is impaired, such as in recovery from an exacerbation, where the patient's inhalation is much faster and shorter. Here we compare differences in deposition of inhaler particles (10, 4 μm) in the airways of three patients. We aimed to evaluate deposition differences between healthy and impaired breathing with image-based healthy and diseased patient models. We found that the ratio of drug in the lower to upper lobes was 35% larger with a healthy inhalation. For smaller particles the upper airway deposition was similar in all patients, but local deposition hotspots differed in size, location and intensity. Our results identify that image-based airways must be used in respiratory modelling. Various inhalation profiles should be tested for optimal prediction of inhaler deposition.

Nanomedicine formulations for respiratory infections by inhalation delivery: Covid-19 and beyond

For respiratory infections treatment and prevention, we analyze for the first time the possibility of providing a broad range medication based on metallic nanoparticles colloids (NpC) delivery by controlled aerosol inhalation. (i) Based on in-vitro data combined with aerosol deposition characteristics in the respiratory system, we calculate the required effective formulations, dosages and delivery parameters for an aerosol inhalation treatment. The goal is to achieve an effective NpC inhibitory concentration (IC) in the target airway surface liquid (ASL); (ii) We evaluate the clinical safety of such dosages, drawing on information from animal testing data and regulatory limits in the USA for such nanoparticles aerosol inhalation safety. Our analysis indicates a wide range of potentially safe and effective dosages that can be clinically explored, targeting the upper respiratory and bronchial tree system. Similar dosages can also provide antibacterial effectiveness for prophylactic treatment in hospital intensive care units to lower the risk of ventilator-associated pneumonia (VAP).

Our calculations are phenomenological, independent of mechanisms. Nevertheless, we highlight a mechanism of action by which any suitably designed NpC, with nanoparticles sized 2–10 nm and having a large negative zeta-potential, preferentially bind to viruses with predominantly positively-charged spike proteins. These will be ineffective against viruses with predominantly negatively-charged spike proteins. Accordingly, the popular silver metal base for NpC serves just as a construction ingredient, and other metal or metal-oxides which can serve to construct the noted nanoparticle properties would be similarly effective.

We suggest that inhalation delivery of the proposed antiviral formulations could be applied as a first-line intervention while respiratory infections are primarily localized to the upper respiratory system and bronchial tree.

A scintigraphy study of budesonide/glycopyrrolate/formoterol fumarate metered dose inhaler in patients with moderate-to-very severe chronic obstructive pulmonary disease

BACKGROUND

Triple therapy with inhaled corticosteroids/long-acting muscarinic antagonists/long-acting β2-agonists (ICS/LAMA/LABA) is recommended for patients with chronic obstructive pulmonary disease (COPD) with continued symptoms or exacerbations, despite treatment with LAMA/LABA or ICS/LABA. The pulmonary, extrathoracic, and regional lung deposition patterns of a radiolabeled ICS/LAMA/LABA triple fixed-dose combination budesonide/glycopyrrolate/formoterol fumarate (BGF 320/18/9.6 μg), delivered via a single Aerosphere metered dose inhaler (MDI) were previously assessed in healthy volunteers and showed good deposition to the central and peripheral airways (whole lung deposition: 37.7%). Here, we report the findings assessing BGF in patients with moderate-to-very severe COPD.

METHODS

This phase I, single-dose, open-label gamma scintigraphy imaging study (NCT03906045) was conducted in patients with moderate-to-very severe COPD. Patients received two actuations of BGF MDI (160/9/4.8 μg per actuation) radiolabeled with technetium‑99‑pertechnetate, not exceeding 5 MBq per actuation. Immediately following each inhalation, patients performed a breath-hold of up to 10 s, then exhaled into an exhalation filter. Gamma scintigraphy imaging of the anterior and posterior views of the lungs and stomach, and a lateral head and neck view, were performed immediately after exhalation. The primary objective of the study was to assess the pulmonary deposition of BGF. Secondary objectives assessed the deposited dose of radiolabeled BGF in the oropharyngeal and stomach regions, on the actuator, and on the exhalation filter in addition to regional airway deposition patterns in the lungs.

RESULTS

The mean BGF emitted dose deposited in the lungs was 32.1% (standard deviation [SD] 15.6) in patients with moderate-to-very severe COPD, 35.2% (SD 12.8) in patients with moderate COPD, and 28.7% (SD 18.4) in patients with severe/very severe COPD. Overall, the mean normalized outer/inner ratio was 0.55 (SD 0.19), while the standardized central/peripheral ratio was 2.21 (SD 1.64).

CONCLUSIONS

Radiolabeled BGF 320/18/9.6 μg was efficiently delivered and deposited throughout the entire lung, including large and small airways, in patients with moderate-to-very severe COPD, with similar deposition in patients with moderate COPD and patients with severe/very severe COPD.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03906045. Registered 8 April 2019, https://clinicaltrials.gov/ct2/show/NCT03906045.

Dry Powder Inhalers in the Digitalization Era: Current Status and Future Perspectives

During the last decades, the term "drug delivery systems" (DDSs) has almost fully replaced previously used terms, such as "dosage forms", in an attempt to emphasize the importance of the drug carrier in ensuring the claimed safety and effectiveness of the product. However, particularly in the case of delivery devices, the term "system", which by definition implies a profound knowledge of each single part and their interactions, is not always fully justified when using the DDS term. Within this context, dry powder inhalers (DPIs), as systems to deliver drugs via inhalation to the lungs, require a deep understanding of the complex formulation-device-patient interplay. As of now and despite the progress made in particle engineering and devices design, DPIs' clinical performance is limited by variable patients' breathing patterns. To circumvent this pitfall, next-generation DPIs should ideally adapt to the different respiratory capacity of individuals across age, health conditions, and other related factors. In this context, the recent wave of digitalization in the health care and industrial sectors may drive DPI technology towards addressing a personalized device-formulation-patient liaison. In this review, evolving technologies are explored and analyzed to outline the progress made as well as the gaps to fill to align novel DPIs technologies with the systems theory approach.

A numerical study of the effects of ambient temperature and humidity on the particle growth and deposition in the human airway

A numerical study was conducted on the effects of ambient temperature and humidity on the transportation of sodium chloride particles (100 nm-1 μm) in a human airway model ranging from the nasal cavity to bronchi. A mucus-tissue structure was adopted to model the mass and heat transfer on the airway surface boundary. The temperature and humidity distributions of the respiratory flow were calculated and then the interaction between the particle and water vapor was further analyzed. It was predicted that the particle size grew to the ratio of 5-6 under subsaturation conditions because of hygroscopicity, which shifted the deposition efficiency in opposite directions on dependence of the initial particle size. However, the particles could be drastically raised to 40 times of the initial 100 nm diameter if the supersaturation-induced condensation was established, that was prone to occur under the cold-dry condition, and consequently promoted the deposition significantly. Such behavior might effectively contribute to the revitalized coronavirus disease 2019 (COVID-19) pandemic in addition to the more active virus itself in winter.

Why We Should Target Small Airways Disease in Our Management of Chronic Obstructive Pulmonary Disease

For more than 50 years, small airways disease has been considered a key feature of chronic obstructive pulmonary disease (COPD) and a major cause of airway obstruction. Both preventable and treatable, small airways disease has important clinical consequences if left unchecked. Small airways disease is associated with poor spirometry results, increased lung hyperinflation, and poor health status, making the small airways an important treatment target in COPD. The early detection of small airways disease remains the key barrier; if detected early, treatments designed to target small airways may help reduce symptoms and allow patients to maintain their activities. Studies are needed to evaluate the possible role of new drugs and novel drug formulations, inhalers, and inhalation devices for treating small airways disease. These developments will help to improve our management of small airways disease in patients with COPD.

Innovating on Inhaled Bioequivalence: A Critical Analysis of the Current Limitations, Potential Solutions and Stakeholders of the Process

Orally inhaled drug products (OIDPs) are an important group of medicines traditionally used to treat pulmonary diseases. Over the past decade, this trend has broadened, increasing their use in other conditions such as diabetes, expanding the interest in this administration route. Thus, the bioequivalence of OIDPs is more important than ever, aiming to increase access to affordable, safe and effective medicines, which translates into better public health policies. However, regulatory agencies leading the bioequivalence process are still deciding the best approach for ensuring a proposed inhalable product is bioequivalent. This lack of agreement translates into less cost-effective strategies to determine bioequivalence, discouraging innovation in this field. The Next-Generation Impactor (NGI) is an example of the slow pace at which the inhalation field evolves. The NGI was officially implemented in 2003, being the last equipment innovation for OIDP characterization. Even though it was a breakthrough in the field, it did not solve other deficiencies of the BE process such as dissolution rate analysis on physiologically relevant conditions, being the last attempt of transferring technology into the field. This review aims to reveal the steps required for innovation in the regulations defining the bioequivalence of OIDPs, elucidating the pitfalls of implementing new technologies in the current standards. To do so, we collected the opinion of experts from the literature to explain these trends, showing, for the first time, the stakeholders of the OIDP market. This review analyzes the stakeholders involved in the development, improvement and implementation of methodologies that can help assess bioequivalence between OIDPs. Additionally, it presents a list of methods potentially useful to overcome some of the current limitations of the bioequivalence standard methodologies. Finally, we review one of the most revolutionary approaches, the inhaled Biopharmaceutical Classification System (IBCs), which can help establish priorities and order in both the innovation process and in regulations for OIDPs.

Cylindrical Microparticles Composed of Mesoporous Silica Nanoparticles for the Targeted Delivery of a Small Molecule and a Macromolecular Drug to the Lungs: Exemplified with Curcumin and siRNA

The transport of macromolecular drugs such as oligonucleotides into the lungs has become increasingly relevant in recent years due to their high potency. However, the chemical structure of this group of drugs poses a hurdle to their delivery, caused by the negative charge, membrane impermeability and instability. For example, siRNA to reduce tumour necrosis factor alpha (TNF-α) secretion to reduce inflammatory signals has been successfully delivered by inhalation. In order to increase the effect of the treatment, a co-transport of another anti-inflammatory ingredient was applied. Combining curcumin-loaded mesoporous silica nanoparticles in nanostructured cylindrical microparticles stabilized by the layer-by-layer technique using polyanionic siRNA against TNF-α was used for demonstration. This system showed aerodynamic properties suited for lung deposition (mass median aerodynamic diameter of 2.85 ± 0.44 µm). Furthermore, these inhalable carriers showed no acute in vitro toxicity tested in both alveolar epithelial cells and macrophages up to 48 h incubation. Ultimately, TNF-α release was significantly reduced by the particles, showing an improved activity co-delivering both drugs using such a drug-delivery system for specific inhibition of TNF-α in the lungs.

Sufentanil EC50 for endotracheal intubation with aerosol inhalation of carbonated lidocaine by ultrasonic atomizer

BACKGROUND

Nebulized lidocaine reduced stress response for endotracheal intubation. However, the impact of novel lidocaine aerosol inhalation for intubation by ultrasonic atomizer was unclear. Hence, we designed aerosol inhalation of lidocaine by ultrasonic atomizer, to seek whether the dosage of sufentanil for intubation could be less or not.

METHODS

Intravenous injection of sufentanil started at 0.5 μg/kg, and sufentanil dosage was increased/decreased (step-size 0.05 μg/kg for sufentanil) using Dixon's up and down method. The observation was terminated after 8 reflexes.

RESULTS

The EC50 and EC95 of sufentanil with lidocaine by ultrasonic atomizer for intubation were found to be 0.232 μg/kg (95% CI: 0.187-0.270 μg/kg) and 0.447 μg/kg (95% CI: 0.364-0.703 μg/kg). 55.88% out of 34 patients showed hemodynamic index change < 20% of baseline during intubation.

CONCLUSION

Aerosol inhalation of lidocaine by ultrasonic atomizer reduced the dosage of sufentanil for endotracheal intubation. Lidocaine inhalation by ultrasonic atomizer for airway anesthesia with minimal dosage of sufentanil could be recommended, particularly in patients who need more stable hemodynamic changes or spontaneous respiration.

TRIAL REGISTRATION

Chinese Registry of Central Trial, ChiCTR-IOR-17014198 . Registered 28 December 2017.

Comparative in-vitro Study of the Trachospray, a New Device for Topical Anaesthesia of the Upper Airway

Background

Obtaining complete topical anaesthesia of the airway remains a clinical challenge. Particle size is one of the most important variables for the dose deposited and the distribution of aerosols in the airways. The mass median aerodynamic diameter of the particles should be in the range of 5–20 µm. We developed the “Trachospray” as a soft mist spray device for local anaesthetics. This in-vitro comparative test was designed to compare the performance of the new Trachospray device with two existing medical devices. The performance was determined by comparing the spray deposition patterns in the mouth, throat, trachea and lungs.

Methods

The human airway was simulated with an artificial idealized mouth and throat model, connected to a Next Generation Impactor. Four measurements were taken for each device (Trachospray, jet nebulizer and a spray pump) with 5.85% NaCl. A fifth measurement was carried out with 0.5% fluorescein solution for a visual inspection of the deposition patterns. The mass median aerodynamic diameter and geometric standard deviation of the droplets were measured.

Results

The Trachospray produced an even coverage in the mouth, hypopharynx and vocal cords, with only a small lung fraction. The jet nebulizer produced a much thinner layer coverage of the tongue and surface around the vocal chords with a high lung deposition. The spray pump produced big droplets which deposited mainly at the hypopharynx.

Conclusion

The Trachospray device deposits local anaesthetics in the targeted areas for topical anaesthesia of the airway and has promising characteristics for providing effective airway anaesthesia.

Consistent Pulmonary Drug Delivery with Whole Lung Deposition Using the Aerosphere Inhaler: A Review of the Evidence

Metered dose inhalers (MDIs) are one of the most common device types for delivering inhaled therapies. However, there are several technical challenges in development and drug delivery of these medications. In particular, suspension-based MDIs are susceptible to suspension heterogeneity, in vitro drug–drug interactions, and patient handling errors, which may all affect drug delivery. To overcome these challenges, new formulation approaches are required. The Aerosphere^TM inhaler, formulated using co-suspension delivery technology, combines drug crystals with porous phospholipid particles to create stable, homogenous suspensions that dissolve once they reach the airways. Two combination therapies using this technology have been developed for the treatment of COPD: glycopyrrolate/formoterol fumarate (GFF MDI; dual combination) and budesonide/glycopyrrolate/formoterol fumarate (BGF MDI; triple combination). Here, we review the evidence with a focus on studies assessing dose delivery, lung deposition, and effects on airway geometry. In vitro assessments have demonstrated that the Aerosphere inhaler provides consistent dose delivery, even in the presence of simulated patient handling errors. Combination therapies delivered with this technology also show a consistent fine particle fraction (FPF) and an optimal particle size distribution for delivery to the central and peripheral airways even when multiple drugs are delivered via the same inhaler. Studies using gamma scintigraphy and functional respiratory imaging have demonstrated that GFF MDI is effectively deposited in the central and peripheral airways, and provides clinically meaningful benefits on airway volume and resistance throughout the lung. Overall, studies suggest that the Aerosphere inhaler, formulated using co-suspension delivery technology, may offer advantages over traditional formulations, including consistent delivery of multiple components across patient handling conditions, optimal particle size and FPF, and effective delivery to the central and peripheral airways. Future studies may provide additional evidence to further characterize the clinical benefits of these technical improvements in MDI drug delivery.

siRNA delivery to macrophages using aspherical, nanostructured microparticles as delivery system for pulmonary administration

The delivery of oligonucleotides such as siRNA to the lung is a major challenge, as this group of drugs has difficulties to overcome biological barriers due to its polyanionic character and the associated hydrophilic properties, resulting in inefficient delivery. Especially in diseases such as asthma, chronic obstructive pulmonary disease and cystic fibrosis, where increased proinflammation is present, a targeted RNA therapy is desirable due to the high potency of these oligonucleotides. To address these problems and to ensure efficient uptake of siRNA in macrophages, a microparticulate, cylindrical delivery system was developed. In the first step, this particle system was tested for its aerodynamic characteristics to evaluate the aerodynamic properties to optimize lung deposition. The mass median aerodynamic diameter of 2.52 ± 0.23 µm, indicates that the desired target should be reached. The inhibition of TNF-α release, as one of the main mediators of proinflammatory reactions, was investigated. We could show that our carrier system can be loaded with siRNA against TNF-α. Gel electrophoreses allowed to demonstrate that the load can be incorporated and released without being degraded. The delivery system was found to transport a mass fraction of 0.371% [%w/w] as determined by inductively coupled plasma mass spectroscopy. When investigating the release kinetics, the results showed that several days are necessary to release a major amount of the siRNA indicating a sustained release. The cylindrical microparticles with an aspect ratio of 3.3 (ratio of length divided by width) were then tested in vitro successfully reducing TNF-α release from human macrophages significantly by more than 30%. The developed formulation presents a possible oligonucleotide delivery system allowing due to its internal structure to load and protect siRNA.

Decoding (patho-)physiology of the lung by advanced in vitro models for developing novel anti-infectives therapies

Advanced lung cell culture models provide physiologically-relevant and complex data for mathematical models to exploit host-pathogen responses during anti-infective drug testing.

Development of a dynamic in vitro stretch model of the alveolar interface with aerosol delivery

We describe the engineering design, computational modeling, and empirical performance of a moving air-liquid interface (MALI) bioreactor for the study of aerosol deposition on cells cultured on an elastic, porous membrane which mimics both air-liquid interface exposure conditions and mechanoelastic motion of lung tissue during breathing. The device consists of two chambers separated by a cell layer cultured on a porous, flexible membrane. The lower (basolateral) chamber is perfused with cell culture medium simulating blood circulation. The upper (apical) chamber representing the air compartment of the lung is interfaced to an aerosol generator and a pressure actuation system. By cycling the pressure in the apical chamber between 0 and 7 kPa, the membrane can mimic the periodic mechanical strain of the alveolar wall. Focusing on the engineering aspects of the system, we show that membrane strain can be monitored by measuring changes in pressure resulting from the movement of media in the basolateral chamber. Moreover, liquid aerosol deposition at a high dose delivery rate (>1 µl cm^-2  min^-1 ) is highly efficient (ca. 51.5%) and can be accurately modeled using finite element methods. Finally, we show that lung epithelial cells can be mechanically stimulated under air-liquid interface and stretch-conditions without loss of viability. The MALI bioreactor could be used to study the effects of aerosol on alveolar cells cultured at the air-liquid interface in a biodynamic environment or for toxicological or therapeutic applications.

Construction of a hybrid lung model by combining a real geometry of the upper airways and an idealized geometry of the lower airways

BACKGROUND AND OBJECTIVE

Health care costs represent a substantial an increasing percentage of global expenditures. One key component is treatment of respiratory diseases, which account for one in twelve deaths in Europe. Computational simulations of lung airflow have potential to provide considerable cost reduction and improved outcomes. Such simulations require accurate in silico modeling of the lung airway. The geometry of the lung is extremely complex and for this reason very simple morphologies have primarily been used to date. The objective of this work is to develop an effective methodology for the creation of hybrid pulmonary geometries combining patient-specific models obtained from CT images and idealized pulmonary models, for the purpose of carrying out experimental and numerical studies on aerosol/particle transport and deposition in inhaled drug delivery.

METHODS

For the construction of the hybrid numerical model, lung images obtained from computed tomography were exported to the DICOM format to be treated with a commercial software to build the patient-specific part of the model. At the distal terminus of each airway of this portion of the model, an idealization of a single airway path is connected, extending to the sixteenth generation. Because these two parts have different endings, it is necessary to create an intermediate solid to link them together. Physically realistic treatment of truncated airway boundaries in the model was accomplished by mapping of the flow velocity distribution from corresponding conducting airway segments.

RESULTS

The model was verified using two sets of simulations, steady inspiration/expiration and transient simulation of forced spirometry. The results showed that the hybrid model is capable of providing a realistic description of air flow dynamics in the lung while substantially reducing computational costs relative to models of the full airway tree.

CONCLUSIONS

The model development outlined here represents an important step toward computational simulation of lung dynamics for patient-specific applications. Further research work may consist of investigating specific diseases, such as chronic bronchitis and pulmonary emphysema, as well as the study of the deposition of pollutants or drugs in the airways.

Preclinical Development of Orally Inhaled Drugs (OIDs)-Are Animal Models Predictive or Shall We Move Towards In Vitro Non-Animal Models?

Respiratory diseases constitute a huge burden in our society, and the global respiratory drug market currently grows at an annual rate between 4% and 6%. Inhalation is the preferred administration method for treating respiratory diseases, as it: (i) delivers the drug directly at the site of action, resulting in a rapid onset; (ii) is painless, thus improving patients' compliance; and (iii) avoids first-pass metabolism reducing systemic side effects. Inhalation occurs through the mouth, with the drug generally exerting its therapeutic action in the lungs. In the most recent years, orally inhaled drugs (OIDs) have found application also in the treatment of systemic diseases. OIDs development, however, currently suffers of an overall attrition rate of around 70%, meaning that seven out of 10 new drug candidates fail to reach the clinic. Our commentary focuses on the reasons behind the poor OIDs translation into clinical products for the treatment of respiratory and systemic diseases, with particular emphasis on the parameters affecting the predictive value of animal preclinical tests. We then review the current advances in overcoming the limitation of animal animal-based studies through the development and adoption of in vitro, cell-based new approach methodologies (NAMs).

Pulmonary deposition of budesonide/glycopyrronium/formoterol fumarate dihydrate metered dose inhaler formulated using co-suspension delivery technology in healthy male subjects

This gamma scintigraphy imaging study assessed pulmonary, extrathoracic and regional lung deposition patterns of a radiolabelled inhaled corticosteroid/long-acting muscarinic antagonist/long-acting β₂-agonist triple fixed-dose combination budesonide/glycopyrronium/formoterol fumarate dihydrate (BGF 320/14.4/10 μg), delivered by pressurised metered dose inhaler (pMDI) using innovative co-suspension delivery technology (Aerosphere™). In this Phase I, randomised, single-centre, single-dose, two-period, crossover study (NCT03740373), 10 healthy male adults received two actuations of BGF MDI (160/7.2/4.8 μg per actuation) radiolabelled with ^99mTc, not exceeding 5 MBq per actuation. Immediately following each inhalation, subjects performed a 10- or 3-second breath-hold, then exhaled into an exhalation filter. The primary objective was to assess the pulmonary deposition of BGF MDI following the 10-second breath-hold. The secondary objectives were to assess deposition after the 3-second breath-hold and lung regional and extrathoracic deposition after each breath-hold length. Imaging of the lungs, stomach, head and neck was recorded by gamma scintigraphy immediately after exhalation. The mean BGF MDI emitted dose deposited in the lungs was 37.7% for the 10-second breath-hold and 34.5% for the 3-second breath-hold. Emitted dose detected in the exhalation filter was ≤0.4% for both breath-hold lengths. The mean normalised peripheral/central ratio was 0.65 and 0.75 for the 10- and 3-second breath-holds, respectively, while the standardised central/peripheral ratios were 1.79 and 1.40, respectively. There were no new or unexpected safety findings. In conclusion, BGF MDI was efficiently deposited in the central and the peripheral regions of the lungs, with similar regional deposition patterns following a 10- and 3-second breath-hold.

Realizing Lobe-Specific Aerosol Targeting in a 3D-Printed In Vitro Lung Model

Background: Delivery of aerosols to isolated lobes of the lungs would be beneficial for diseases that have lobe-specific effects, such as cancer, pneumonia, and chronic obstructive pulmonary disorder. Recent computational fluid-particle dynamic (CFPD) modeling has demonstrated that in low flow rates, the inlet location of a particle at the mouth dictates the lobe into which it will deposit. However, realization of this lobe-specific deposition has yet to be attempted experimentally or in the clinic. To address this, we sought to develop a proof-of-concept in vitro model and targeting device for achieving lobe-specific delivery. Methods: Using 3D printing, a lung replica was created from a computed tomography scan of a healthy 47-year-old male volunteer and connected to a flow setup to control inlet flow rate and outlet airflow distribution to each lobe. A device was designed and fabricated that directs particles to an inlet location that is 5% of the total inlet area and described by radial coordinates (r,θ). Filter paper at sampling ports for each lobe was used to capture fluorescent polystyrene particles to quantify particle collection. We evaluated lobe-specific targeting at varied inlet coordinates, particle diameters, inlet flow rates, and disease lobe flow rate distribution profiles. Results: Guided by CFPD modeling, inlet locations were identified that increased particle collection to a target lobe between 63% and 90%. For example, release of fluorescent particles at the inlet location r = 4.67 mm, θ = 252° with respect to the center of the inlet using 1 μm particles, 1 L/min inlet flow rate, and healthy subject lobe flow distribution profile yielded 90% of the aerosol dose to the right upper lobe, corresponding to an increase of 4.6 × above the non-targeted percent particle collection. Particle size, inlet flow rate, and disease airflow distributions were all shown to generally decrease the efficiency of lobe-specific targeting. Conclusions: Our results indicate that aerosol targeting of a specific lobe is possible in vitro under optimized conditions and that controlling inlet locations could be a potentially useful method for treatment of lobe-specific diseases. This is the first demonstration of lobe-specific particle collection in a physical lung model and illuminates numerous challenges that will be faced as this method is translated to clinical applications.

Ventilation/Perfusion Relationships and Gas Exchange: Measurement Approaches

Ventilation-perfusion ( V ˙ A / Q ˙ ) matching, the regional matching of the flow of fresh gas to flow of deoxygenated capillary blood, is the most important mechanism affecting the efficiency of pulmonary gas exchange. This article discusses the measurement of V ˙ A / Q ˙ matching with three broad classes of techniques: (i) those based in gas exchange, such as the multiple inert gas elimination technique (MIGET); (ii) those derived from imaging techniques such as single-photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI), computed tomography (CT), and electrical impedance tomography (EIT); and (iii) fluorescent and radiolabeled microspheres. The focus is on the physiological basis of these techniques that provide quantitative information for research purposes rather than qualitative measurements that are used clinically. The fundamental equations of pulmonary gas exchange are first reviewed to lay the foundation for the gas exchange techniques and some of the imaging applications. The physiological considerations for each of the techniques along with advantages and disadvantages are briefly discussed. © 2020 American Physiological Society. Compr Physiol 10:1155-1205, 2020.

Feasibility of Aerosolized Alpha-1 Antitrypsin as a Therapeutic Option

Inhalation therapy is integral in the management of patients with chronic obstructive pulmonary disease (COPD). Specifically, intravenous augmentation therapy is available to patients with alpha-1 antitrypsin deficiency (AATD), although there is insufficient alpha-1 antitrypsin (AAT) delivery to the lungs to modify airways inflammation. In contrast, the inhaled route allows replacement therapy to reach the target site of action and with higher AAT levels. Patients certainly support the inhalation route as an alternative to intravenous injections, obviating repetitive needle insertion and allowing treatment empowerment rather than dependency on traveling to specialized units. The difficulty with inhalation has been the ability to target the formulation to the pathophysiological site of disease: the emphysematous lung parenchyma of the small alveolated airways. Recent advances have suggested nebulizers as being able to deliver an adequate dose, consistently and reproducibly, and, coupled with developments in formulation science, allowed replacement therapy to reach the epithelial lining fluid of the small airways. The bench science has been translated to the first randomized, placebo-controlled clinical trial to study the effects of nebulized AAT, which, although not meeting the primary endpoint of prolonging time to first exacerbation, showed this treatment modality was safe and achievable in a large patient cohort. Indeed, learning from this trial suggests the importance of choosing the right clinical endpoints, and recent key advances in lung physiology indices allow better assessment of the "silent zone" of small airways disease. Knowledge from other respiratory diseases will complement treating patients with AATD, where there is considerable innovation in aerosol science and inhalation medicine directed at utilizing the inhaled route. Indeed, it could be postulated that the inhaled route may not only achieve local pulmonary therapeutic benefit, but through systemic absorption and controlled pharmacokinetic profiling, the formulation may reach and treat liver disease.

Future Trends in Nebulized Therapies for Pulmonary Disease

Aerosol therapy is a key modality for drug delivery to the lungs of respiratory disease patients. Aerosol therapy improves therapeutic effects by directly targeting diseased lung regions for rapid onset of action, requiring smaller doses than oral or intravenous delivery and minimizing systemic side effects. In order to optimize treatment of critically ill patients, the efficacy of aerosol therapy depends on lung morphology, breathing patterns, aerosol droplet characteristics, disease, mechanical ventilation, pharmacokinetics, and the pharmacodynamics of cell-drug interactions. While aerosol characteristics are influenced by drug formulations and device mechanisms, most other factors are reliant on individual patient variables. This has led to increased efforts towards more personalized therapeutic approaches to optimize pulmonary drug delivery and improve selection of effective drug types for individual patients. Vibrating mesh nebulizers (VMN) are the dominant device in clinical trials involving mechanical ventilation and emerging drugs. In this review, we consider the use of VMN during mechanical ventilation in intensive care units. We aim to link VMN fundamentals to applications in mechanically ventilated patients and look to the future use of VMN in emerging personalized therapeutic drugs.

ATTACHED, DETACHED and WITHOUT inhaler technique coaching tools to optimize pMDI use competence, asthma control and quality-of-life in asthmatic adults

Background

Poor pressurized metered dose inhaler (pMDI) technique is prevalent, which will diminish treatment gains. In a two-visit study, two novel pMDI training devices with feedback mechanisms; Trainhaler (THR) and Flo-Tone CR (FTCR), were evaluated alongside the traditional verbal inhaler training (VT) in asthma outpatients.

Methods

On visit 1, 18-60 year-old asthmatics with incorrect pMDI use [including peak inhalation flow (PIF) >60 L/min] signed consent and baseline pMDI technique, lung function, asthma control and quality-of-life were measured. Participants were randomized to receive pMDI technique training using VT, THR or FTCR. One hour post-training, the pMDI coordination and PIF were re-assessed. The THR and FTCR patients were given their assigned tools to take home to facilitate regular training. All outcomes were re-evaluated 6-8 weeks later (visit 2).

Results

Ninety-two asthmatics completed visit 1 (46 attended visit 2). Pre-training, 61.3% (VT), 61.5% (THR) and 65.0% (FTCR) patients similarly made ≥2 pMDI errors with mean PIFs 175.2, 187.1 and 158.9 L/min, respectively. pMDI use was significantly improved 1 h post-training. The subjects that completed visit 2 had significantly, yet equally, maintained the improved inhaler use; only 28.0% (VT), 26.2% (THR) and 21.7% (FTCR) patients made ≥2 pMDI errors with PIF improvements; 115.3, 94.6 and 96.1 L/min, respectively. Clinical outcomes remained comparable.

Conclusions

VT improves the overall pMDI technique, however patients gradually forget their VT. The THR and FTCR devices are retained by the patients as their self-monitoring, all-time personal trainers that boost and maintain their VT between routine clinic visits.

Ventilation Modulation and Nanoparticle Deposition in Respiratory and Olfactory Regions of Rabbit Nose

The rabbit nose's ability to filter out inhaled agents is directly related to its defense to infectious diseases. The knowledge of the rabbit nose anatomy is essential to appreciate its functions in ventilation regulation, aerosol filtration and olfaction. The objective of this study is to numerically simulate the inhalation and deposition of nanoparticles in a New Zealand white (NZW) rabbit nose model with an emphasis on the structure-function relation under normal and sniffing conditions. To simulate the sniffing scenario, the original nose model was modified to generate new models with enlarged nostrils or vestibules based on video images of a rabbit sniffing. Ventilations into the maxilloturbinate and olfactory region were quantified with varying nostril openings, and deposition rates of inhaled aerosols ranging from 0.5 nm to 1000 nm were characterized on the total, sub-regional and local basis. Results showed that particles which deposited in the olfactory region came from a specific area in the nostril. The spiral vestibule played an essential role in regulating flow resistance and flow partition into different parts of the nose. Increased olfactory doses were persistently predicted in models with expanded nostrils or vestibule. Particles in the range of 5-50 nm are more sensitive to the geometry variation than other nanoparticles. It was also observed that exhaled aerosols occupy only the central region of the nostril, which minimized the mixing with the aerosols close to the nostril wall, and potentially allowed the undisruptive sampling of odorants. The results of this study shed new light on the ventilation regulation and inhalation dosimetry in the rabbit nose, which can be further implemented to studies of infectious diseases and immunology in rabbits.

Roles of Relative Humidity in Aerosol Pollution Aggravation over Central China during Wintertime

Aerosol pollution elicits considerable public concern due to the adverse influence on air quality, climate change, and human health. Outside of emissions, haze formation is closely related to meteorological conditions, especially relative humidity (RH). Partly due to insufficient investigations on the aerosol hygroscopicity, the accuracy of pollution prediction in Central China is limited. In this study, taking Wuhan as a sample city, we investigated the response of aerosol pollution to RH during wintertime based on in-situ measurements. The results show that, aerosol pollution in Wuhan is dominated by PM_2.5 (aerodynamic particle size not larger than 2.5 μm) on wet days (RH ≥ 60%), with the averaged mass fraction of 0.62 for PM₁₀. Based on the RH dependence of aerosol light scattering (f (RH)), aerosol hygroscopicity was evaluated and shows the high dependence on the particle size distribution and chemical compositions. f (RH = 80%) in Wuhan was 2.18 (±0.73), which is comparable to that measured in the Pearl River Delta and Yangtze River Delta regions for urban aerosols, and generally greater than values in Beijing. Ammonium (NH₄⁺), sulfate (SO₄²⁻), and nitrate (NO₃⁻) were enhanced by approximately 2.5-, 2-, and 1.5-fold respectively under wet conditions, and the ammonia-rich conditions in wintertime efficiently promoted the formation of SO₄²⁻ and NO₃⁻, especially at high RH. These secondary ions play an important role in aggravating the pollution level and aerosol light scattering. This study has important implications for understanding the roles of RH in aerosol pollution aggravation over Central China, and the fitted equation between f (RH) and RH may be helpful for pollution forecasting in this region.

Evaluation of patients' real-world post-dispensing use and storage environments of tiotropium bromide Respimat® soft mist inhaler on its in vitro dose delivery and lung deposition

BACKGROUND

Oral inhalation is the main drug delivery route for treating obstructive lung conditions. Thus, many inhaler devices with various design and pharmaceutical formulation have been introduced. The fine particle dose (FPD) and mass median aerodynamic diameter (MMAD ≤ 5 μm) of the aerosol delivered dose (DD) dictate the therapeutically effective peripheral lung deposition. This study evaluated the in vitro aerosol emission performance of tiotropium bromide emitted from Spiriva® Respimat® soft mist inhalers (R) after living under patients' real-world, post-dispensing handling environments.

METHODS

This was a two-stage investigation. In the first clinical stage, research ethical approval was obtained to enrol patients already been using R for at least 3 months. Those who signed consent were given both new R to use and temperature and relative humidity (RH) handheld, portable data loggers to keep in the vicinity of the given R. The participants returned the given R and data loggers after 2 weeks. Patient recruitment took place in Amman, Jordan, during the summer (RS) and winter (RW). Subsequently, in the second laboratory stage, other R were strictly stored at an average of 21.0 °C and 46.9% RH as control (RC). The Next Generation Impactor (NGI) was used to evaluate the RS, RW and RC. The NGI was operated at a flow rate of 30 L/min.

RESULTS

The RS were exposed to an average (range) 23.6 °C (18.2-37.5 °C) and 43.8% RH (21.4-60.0% RH) that were statistically comparable (p > 0.05) to that of the RW; 17.3 °C (13.2-26.7 °C) and 52.8% RH (26.3-69.1% RH). The RW and RC retention environments were statistically different (p < 0.05), whilst the RS and RC had comparable (p > 0.05) conditions. No significant differences (p > 0.05) were found in the tiotropium bromide DD (2.39 vs 2.43 μg), FPD (0.88 vs 0.90 μg) and MMAD (5.1 vs 4.98 μm) between the RS and RW, respectively. Compared to the RC inhalers, both the RS and RW devices had significantly higher FPD and relatively smaller tiotropium bromide particles.

CONCLUSIONS

Using the R under the fluctuating summer and winter environments of our patients would not affect its overall tiotropium bromide emission performance. The significant increase in the respirable mass of the RS and RW might be offset by the increase in particles <1 μm particularly in patients with poor inhaler technique.

Biological Obstacles for Identifying In Vitro-In Vivo Correlations of Orally Inhaled Formulations

Oral inhalation of drugs is the classic therapy of obstructive lung diseases. In contrast to the oral route, the link between in vitro and in vivo findings is less well defined and predictive models and parameters for in vitro-in vivo correlations are missing. Frequently used in vitro models and problems in obtaining in vivo values to establish such models and to identify the action of formulations in vivo are discussed. It may be concluded that major obstacles to link in vitro parameters on in vivo action include lack of treatment adherence and incorrect use of inhalers by patients, variation in inhaler performance, changes by humidity, uncertainties about lung deposition, and difficulties to measure drug levels in epithelial lining fluid and tissue. Physiologically more relevant in vitro models, improvement in inhaler performance, and better techniques for in vivo measurements may help to better understand importance and interactions between individual in vitro parameters in pulmonary delivery.

Delivered Lung Dose and Aerodynamic Particle Size Distribution of Salbutamol Pressurized Metered Dose Inhaler After Living Under Patients' Realistic Retention Environments

Background: The impact of inhalers' postdispensing, real-life temperature and relative humidity (RH) environments on their delivered dose (DD) and aerodynamic particle size distribution (APSD) is usually overlooked. This work evaluated the salbutamol DD and APSD of Ventolin^® Evohaler^® (V) inhalers already been used and stored by respiratory patients. Methods: Adult patients, prescribed V for ≥3 months before study enrollment, were dispensed both new V to use and portable, handheld electronic temperature and RH data loggers to keep close to the given V before returning them both after 2-3 weeks. Patients' enrollment took place during summer (VS) and winter (VW) seasons. The returned V was then in vitro evaluated using the Next Generation Impactor, and compared with control V (VC) counterparts stored under 21°C and 46% RH. Results: The VS survived in fluctuating habitats of 21.2°C-40.4°C and 16.2%-63.2% RH, which significantly (p < 0.05) decreased the salbutamol DD from 80.4 to 70.5 μg compared with VC. This 12.3% DD reduction was accompanied with a decrease in the fine particle dose from 26.2 to 20.4 μg (p < 0.05), and an increase in the mass median aerodynamic diameter from 2.3 to 2.5 μm (p < 0.05). The VW and VC had equivalent DD and APSD. Conclusion: Patients using V are expected to receive smaller lung doses during the hot summer season compared with intentionally well-kept VC. To have equivalent lung deposition, V users should be advised to retain their inhalers around 20°C with minimal daily environmental fluctuations during summer times.

The impact of patients' real-life environmental temperature and humidity use conditions of tiotropium dry powder inhaler on its aerosol emission characteristics

INTRODUCTION

Many factors can affect dry powder inhalers' (DPIs) aerosol emission and lung deposition. The fluctuation of environmental temperature and relative humidity (RH) that inhalers experience in realistic daily use has not been extensively evaluated. This work aimed to evaluate the delivered dose (DD) and aerodynamic particle size distribution (APSD) of tiotropium Handihaler DPI (H) after exposure to patients' real-life use environments.

METHODS

Ethical approval was obtained to enrol adult patients already using H. Patients who gave written consent were given new H to use and HygroLog temperature and RH data loggers to keep in the vicinity of the given inhaler. The H and HygroLog were returned after 2 weeks. Patient recruitment was done during the summer (HS) and winter (HW). As control, other HC were stored as per the leaflet storage instructions. The Next Generation Impactor was used to evaluate the inhalers.

RESULTS

The HC were stored under an average of 21.0 °C and 46.9% RH. The patients' HS and HW lived in an average (range) temperature (°C) 23.2 (18.3-38.2) and 17.8 (13.5-24.6), respectively, and RH 50.8% (24.3-65.3%) and 50.4% (30.6-72.4%), respectively. All H groups had comparable environments (p > 0.05). The HC, HS and HW gave similar tiotropium DD (μg) 7.60, 8.01 and 7.61, respectively (p > 0.05). Moreover, the fine particle dose μg (median diameter (μm)) were HC 2.41 (3.84), HS 2.55 (3.81) and HW 2.37 (3.83) (p > 0.05).

CONCLUSIONS

The aerosol emission behaviour of tiotropium Handihaler was tolerant to real-life retention environments of patients in Amman, Jordan.

The Importance of Inhaler Adherence to Prevent COPD Exacerbations

It has been shown that the better outcomes of chronic obstructive pulmonary disease (COPD) are closely associated with adherence to drug therapy, independent of the treatment administered. The clinical trial Towards a Revolution in COPD Health (TORCH) study clearly showed in a three year follow up that patients with good adherence to their inhaler treatment presented a longer time before the first exacerbation, a lower susceptibility to exacerbation and lower all-cause mortality. The Latin American Study of 24-h Symptoms in Chronic Obstructive Pulmonary Disease (LASSYC), a real-life study, evaluated the self-reported inhaler adherence in COPD patients in seven countries in a cross-sectional non-interventional study and found that approximately 50% of the patients had good adherence, 30% moderate adherence and 20% poor adherence. Adherence to inhaler may be evaluated by the specific inhaler adherence questionnaire, the Test of Adherence to Inhalers (TAI). Several factors may predict the incorrect use of inhalers or adherence in COPD outpatient, including the number of devices and the daily dosing frequency. Ideally, patient education, simplicity of the device operation, the use of just one device for multiple medications and the best adaptation of the patient to the inhaler should guide the physician in prescribing the device.

Characterization and comparison of Re-Du-Ning aerosol particles generated by different jet nebulizers

Inhalation therapy is the first-line therapy for the treatment of respiratory diseases. Re-Du-Ning inhalation solution (RIS) is an aerosol derivative from the Re-Du-Ning injection and has been clinically used to treat respiratory diseases like pneumonia for more than twenty years in China. However, the aerosolization and inhalation performances of RIS using different nebulizers have not been characterized, which may affect the therapeutic effects of RIS on respiratory diseases. We investigated the inhalation performances of RIS using five different nebulizers utilizing Spraytec, breath simulator of BRS 2000 and NGI techniques. We tested 5 different types of jet nebulizer, using RIS and an adult breathing pattern, to determine the difference in aerosol delivery over time. The particle size distribution of RIS was monitored by a Spraytec laser particle sizer. Fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) for RIS were measured using NGI. Aerosol deposited on the filter was analysed using HPLC. Nebulization time was much longer for the Pari Boy SX (red) nebulizer than for the other nebulizers, with the minimum delivery rate (DR) and the maximum total delivered dose (TDD) and total exhalation dose (TED). Nebulization time for Pari Boy SX (blue) was the lowest, with the highest DR and the lowest TDD and TED. Furthermore, the aerodynamic particle size of RIS was much larger for the Pari blue and Pari LC Plus than other nebulizers. Pari red produced the smallest aerodynamic particle size of RIS in these five nebulizers. In addition, a good linear relationship was found between MMAD and D₅₀ in these five nebulizers. The results demonstrated that Pari Boy SX (red) delivered most slowly and produced the smallest aerodynamic particle size of the RIS aerosols, which may be applied to manage lower respiratory diseases. Moreover, Pari LC Plus and Pari Boy SX (blue) emitted quickly and generated larger aerodynamic particle size of RIS aerosols, which could be used to treat upper respiratory diseases. A good linear relationship between MMAD and D₅₀ showed Spraytec could be a reliable technique for the development, evaluation and quality control of aerosol particles of inhalation solution preparations.

Delivery dose uniformity determination by BRS 2000 breath simulator and realtime particle size distribution monitoring by Spraytec.

Models of deposition, pharmacokinetics, and intersubject variability in respiratory drug delivery

INTRODUCTION

Aerosol drug delivery to the lungs via inhalation is widely used in the treatment of respiratory diseases. The deposition pattern of inhaled particles within the airways of the respiratory tract is key in determining the initial delivered dose. Thereafter, dose-dependent processes including drug release or dissolution, clearance, and absorption influence local and systemic exposure to inhaled drugs over time.

AREAS COVERED

Empirical correlations, numerical simulation, and in vitro airway geometries that permit improved prediction of extrathoracic and lung deposition fractions in a variety of age groups and breathing conditions are described. Efforts to link deposition models with pharmacokinetic models predicting lung and systemic exposure to inhaled drugs over time are then reviewed. Finally, new methods to predict intersubject variability in extrathoracic deposition, capturing variability in both size and shape of the upper airways, are highlighted.

EXPERT OPINION

Recent work has been done to expand in vitro deposition experiments to a wide range of age groups and breathing conditions, to link regional lung deposition models with pharmacokinetic models, and to improve prediction of intersubject variability. These efforts are improving predictive understanding of respiratory drug delivery, and will aid the development of new inhaled drugs and delivery devices.

Anatomically Based Analysis of Radioaerosol Distribution in Pulmonary Scintigraphy: A Feasibility Study in Asthmatics

INTRODUCTION

Manual analysis of two-dimensional (2D) scintigraphy to evaluate aerosol deposition is usually subjective and has reduced sensitivity to quantify regional differences between central and distal airways.

AIMS

(1) To present a method to analyze 2D scans based on three-dimensional (3D)-linked anatomically consistent regions of interest (ROIs); (2) to evaluate peripheral-to-central counts ratio (P/C_2D) and penetration indices (PIs) for a set of 16 subjects with moderate-to-severe asthma; and (3) to compare the reproducibility of this method against one with manually traced ROIs.

METHODS

Two-dimensional scans were analyzed using custom software that scaled onto 2D-projections' 3D anatomical features, obtained from population-averaged computed tomography (CT) chest scans. ROIs for a rectangular box (bROI) and an anatomically shaped ROI (aROI) were defined by computer and by manually tracing the standard rectangular box (manual ROI [mROI]). These ROIs were defined five nonconsecutive times for each scan and average value and variability of the P/C_2D were estimated. Based on CT estimates of lung and airways, volumes lying under the bROI and aROI, a 2D penetration index (PI_2D) and a 3D penetration index (PI_3D), were defined as volume-normalized ratios of aerosol deposition in central and peripheral ROIs and in central and distal airways, respectively.

RESULTS

P/C_2D values and their variability, were influenced by the shape and method to define the ROIs: The P/C_2D was systematically greater and more variable for mROI versus bROI (p < 0.005). The P/C_2D for aROI was higher and its variability lower than those for the bROI (p < 0.001). The PI_2D was in average the same for aROI and bROI, and is substantially (∼30 × ) greater than PI_3D (p < 0.001). Both PI_2D and PI_3D, obtained with our analysis, compared well with literature values obtained with two scans (deposition and volume).

CONCLUSION

Our results demonstrate that 2D scintigraphy can be analyzed using anatomically based ROIs from 3D CT data, allowing objective and enhanced reproducibility values describing the distribution pattern of radioaerosol deposition in the tracheobronchial tree.

New developments in optimizing bronchodilator treatment of COPD: a focus on glycopyrrolate/formoterol combination formulated by co-suspension delivery technology

COPD causes considerable health and economic burden worldwide, with incidence of the disease expected to continue to rise. Inhaled bronchodilators, such as long-acting muscarinic antagonists (LAMAs) and long-acting β2-agonists (LABAs), are central to the maintenance treatment of patients with COPD. Clinical studies have demonstrated that combined LAMA + LABA therapies improve efficacy while retaining a safety profile similar to LAMA or LABA alone. This has led to the development of several LAMA/LABA fixed-dose combination (FDC) therapies, which provide patients with the convenience of two active compounds in a single inhaler. GFF MDI (Bevespi Aerosphere®) is an FDC of glycopyrrolate/formoterol fumarate 18/9.6 µg formulated using innovative co-suspension delivery technology for administration via metered dose inhaler (MDI). GFF MDI was developed to make a treatment option available for patients who have a requirement or preference to use an MDI, rather than a dry powder or soft mist inhaler. Now that several LAMA/LABA FDCs have been approved for use in COPD, we review the impact of dual-bronchodilator treatment on COPD therapy and discuss recent clinical studies that are helping to develop a more comprehensive understanding of how LAMA/LABA FDCs can improve patient outcomes.

Is there room for further innovation in inhaled therapy for airways disease?

Inhaled medication is the cornerstone in the treatment of patients across a spectrum of respiratory diseases including asthma and chronic obstructive pulmonary disease. The benefits of inhaled therapy have long been recognised but the most important innovations have occurred over the past 60 years, beginning with the invention of the pressurised metered dose inhaler. However, despite over 230 different device and drug combinations currently being available, disease control is far from perfect. Here we look at how innovation in inhaler design may improve treatments for respiratory diseases and how new formulations may lead to treatments for diseases beyond the lungs. We look at the three main areas where innovation in inhaled therapy is most likely to occur: 1) device engineering and design; 2) chemistry and formulations; and 3) digital technology associated with inhalers. Inhaler design has improved significantly but considerable challenges still remain in order to continually innovate and improve targeted drug delivery to the lungs. Healthcare professionals want see innovations that motivate their patients to achieve their goal of improving their health, through better adherence to treatment. Patients want devices that are easy to use and to see that their efforts are rewarded by improvements in their condition.

KEY POINTS

The dictionary definition of innovation is the introduction of new things, ideas or ways of doing something. We show how this definition can be applied to inhaled therapy.We take a look at the past to see what drove innovation in inhaler design and how this has led to the current devices.We look at the current drivers of innovation in engineering, chemistry and digital technology and predict how this may translate to new devices.Can innovation help the healthcare professional manage their patients better?What does the patient expect from innovation in their device?

EDUCATIONAL AIMS

To understand the importance of inhaled medication in the treatment of lung diseases.To understand how innovation has helped advance some of the devices patients use today from basic and inefficient designs.To understand the obstacles that prevent patients from receiving optimal treatment from their inhalers.To understand how innovation in inhaler design can lead to improved treatment for patients and widen the range of diseases that can be treated via the inhaled route.

Inhaled formulation and device selection: bridging the gap between preclinical species and first-in-human studies

The factors that influence inhaled first-in-human (FIH) device and formulation selection often differ significantly from the factors that have influenced the preceding preclinical experiments and inhalation toxicology work. In order to minimize the risk of delivery issues negatively impacting a respiratory pipeline program, the preclinical and FIH delivery systems must be considered holistically. This topic will be covered in more detail in this paper. Several examples will be presented that highlight how appropriate scientific strategy can help bridge the gap between delivering to preclinical species and human. Considerations for the FIH device selection (metered dose inhaler, dry powder inhaler and nebulizer) and formulation optimization for small molecules will be discussed in context with the preclinical delivery systems.

Quantitative Imaging of Regional Aerosol Deposition, Lung Ventilation and Morphology by Synchrotron Radiation CT

To understand the determinants of inhaled aerosol particle distribution and targeting in the lung, knowledge of regional deposition, lung morphology and regional ventilation, is crucial. No single imaging modality allows the acquisition of all such data together. Here we assessed the feasibility of dual-energy synchrotron radiation imaging to this end in anesthetized rabbits; both in normal lung (n = 6) and following methacholine (MCH)-induced bronchoconstriction (n = 6), a model of asthma. We used K-edge subtraction CT (KES) imaging to quantitatively map the regional deposition of iodine-containing aerosol particles. Morphological and regional ventilation images were obtained, followed by quantitative regional iodine deposition maps, after 5 and 10 minutes of aerosol administration. Iodine deposition was markedly inhomogeneous both in normal lung and after induced bronchoconstrition. Deposition was significantly reduced in the MCH group at both time points, with a strong dependency on inspiratory flow in both conditions (R² = 0.71; p < 0.0001). We demonstrate for the first time, the feasibility of KES CT for quantitative imaging of lung deposition of aerosol particles, regional ventilation and morphology. Since these are among the main factors determining lung aerosol deposition, we expect this imaging approach to bring new contributions to the understanding of lung aerosol delivery, targeting, and ultimately biological efficacy.