Treating the small airways

Pulmonary inhalation for disease treatment: Basic research and clinical translations

Pulmonary drug delivery has the advantages of being rapid, efficient, and well-targeted, with few systemic side effects. In addition, it is non-invasive and has good patient compliance, making it a highly promising drug delivery mode. However, there have been limited studies on drug delivery via pulmonary inhalation compared with oral and intravenous modes. This paper summarizes the basic research and clinical translation of pulmonary inhalation drug delivery for the treatment of diseases and provides insights into the latest advances in pulmonary drug delivery. The paper discusses the processing methods for pulmonary drug delivery, drug carriers (with a focus on various types of nanoparticles), delivery devices, and applications in pulmonary diseases and treatment of systemic diseases (e.g., COVID-19, inhaled vaccines, diagnosis of the diseases, and diabetes mellitus) with an updated summary of recent research advances. Furthermore, this paper describes the applications and recent progress in pulmonary drug delivery for lung diseases and expands the use of pulmonary drugs for other systemic diseases.

Design of dry powder inhalers to improve patient outcomes: it's not just about the device

INTRODUCTION

Up to 50% of asthma/COPD patients make critical errors in dose preparation and dose inhalation with current marketed DPIs which negatively impact clinical outcomes. Others fail to adhere to their chronic treatment regimen.

AREAS COVERED

For this review, we describe how a human-factors approach to design of a dry powder inhaler can be used to improve usability, proficiency, and functionality of DPIs, while effectively mitigating critical errors associated with DPIs. The review highlights the critical importance of utilizing improved formulations with monomodal aerodynamic particle size distributions to reduce variability associated with oropharyngeal filtering of particles, flow rate dependence, and co-formulation effects.

EXPERT OPINION

Much of the variability in dose delivery with DPIs is associated with limitations of the bimodal APSDs inherent in current lactose blend formulations. Evidence supports that improved lung targeting and dose consistency can be achieved with drug-device combination products comprising spray-dried powders. Unfortunately, no data exists to assess whether these advances observed in in vitro and in vivo dose delivery studies will translate into improved clinical outcomes. Given the significant percentage of patients that receive suboptimal drug delivery with current DPIs it would behoove the industry to assess the efficacy of new approaches.

[Small airway: from definition to treatment]

The small airway, present since the origins of humanity and described barely a century ago, has recently been discovered as the anatomical site where inflammation begins in some obstructive lung diseases, such as asthma and Chronic Obstructive Pulmonary Disease (COPD), per se. Small airway dysfuction was identified in up to 91% of asthmatic patients and in a large proportion of COPD patients. In subjects without pathology, small airway represent 98.8% (approximately 4500 ml) of the total lung volume, contributing only between 10-25% of the total lung resistance; however, in subjects with obstruction, it can represent up to 90% of the total resistance. Despite this, its morphological and functional characteristics allow its dysfunction to remain undetected by conventional diagnostic methods, such as spirometry. Hence the importance of this review, which offers an overview of the tools available to assess small airway dysfunction and the possible therapies that act in this silent zone.

Repurposing mucosal delivery devices for live attenuated tuberculosis vaccines

Tuberculosis (TB) remains one of the most lethal infectious diseases globally. The only TB vaccine approved by the World Health Organization, Bacille Calmette-Guérin (BCG), protects children against severe and disseminated TB but provides limited protection against pulmonary TB in adults. Although several vaccine candidates have been developed to prevent TB and are undergoing preclinical and clinical testing, BCG remains the gold standard. Currently, BCG is administered as an intradermal injection, particularly in TB endemic countries. However, mounting evidence from experimental animal and human studies indicates that delivering BCG directly into the lungs provides enhanced immune responses and greater protection against TB. Inhalation therapy using handheld delivery devices is used for some diseases and allows the delivery of drugs or vaccines directly into the human respiratory tract. Whether this mode of delivery could also be applicable for live attenuated bacterial vaccines such as BCG or other TB vaccine candidates remains unknown. Here we discuss how two existing inhalation devices, the mucosal atomization device (MAD) syringe, used for influenza vaccines, and the Respimat® Soft Mist™ inhaler, used for chronic obstructive pulmonary disease (COPD) therapy, could be repurposed for mucosal delivery of live attenuated TB vaccines. We also outline the challenges and outstanding research questions that will require further investigations to ensure usefulness of respiratory delivery devices that are cost-effective and accessible to lower- and middle-income TB endemic countries.

Currently Available Inhaled Therapies in Asthma and Advances in Drug Delivery and Devices

Medications delivered in the inhaled form remains the cornerstone of medical management of asthma. There have been considerable advances in the development of inhaled medications and devices over the past several decades. Clinicians also have access to regularly updated international guidelines for management of asthma. Despite this, a substantial proportion of children with asthma continue to have persistent poor asthma control and considerable morbidity even in well-resourced settings. The wide selection of medications and devices may complicate clinical decision making. The ideal inhaler would be one that the patient can and will use as advised. One cannot overemphasize the importance of medication adherence and a correct inhaler technique in achieving optimal asthma control. Clinicians who manage children with asthma should have a good understanding of inhaled medications and devices commercially available for the management of asthma and this would help them select the right medication and device for the right patient. This review aims to provide an overview of physiologic basis of inhaler therapy, commonly used inhaled therapies, and the advances in the field of inhaler devices including emerging technologies.

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

Targeting of Inhaled Therapeutics to the Small Airways: Nanoleucine Carrier Formulations

Current dry powder formulations for inhalation deposit a large fraction of their emitted dose in the upper respiratory tract where they contribute to off-target adverse effects and variability in lung delivery. The purpose of the current study is to design a new formulation concept that more effectively targets inhaled dry powders to the large and small airways. The formulations are based on adhesive mixtures of drug nanoparticles and nanoleucine carrier particles prepared by spray drying of a co-suspension of leucine and drug particles from a nonsolvent. The physicochemical and aerosol properties of the resulting formulations are presented. The formulations achieve 93% lung delivery in the Alberta Idealized Throat model that is independent of inspiratory flow rate and relative humidity. Largely eliminating URT deposition with a particle size larger than solution pMDIs is expected to improve delivery to the large and small airways, while minimizing alveolar deposition and particle exhalation.

Impact of long-acting muscarinic antagonists on small airways in asthma and COPD: A systematic review

Small airway disease is recognized as a cardinal pathological process of chronic obstructive pulmonary disease (COPD), and recently small airways have been recognized as a major site of airflow obstruction also in asthmatic patients. The transversal involvement of small airways in COPD and asthma has warranted research efforts to identify therapeutic strategies able to unlock the small airway compartment. The mainstay of COPD treatment is represented by long-acting β₂-adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs). In asthma, the efficacy of LAMAs administered add-on to inhaled corticosteroids (ICSs) or ICS/LABA combinations has been investigated only in recent years. The aim of this systematic review was to examine the current literature concerning the impact of LAMAs on small airways and their lung deposition in both COPD and asthma. LAMAs administered either alone or in combination induced an effective bronchorelaxant effect of small airways, however the effectiveness of respiratory medications not only relies on the selected drug, but also on the employed inhalation device and patient's adherence. Tiotropium delivered via Respimat® SMI achieved a superior drug deposition in the peripheral lung compared to HandiHaler® dry powder inhaler and metered-dose inhalers (MDIs). The use of co-suspension™ delivery technology for MDIs and the introduction of the eFlow® nebulizer to deliver glycopyrronium improved aerosol drug delivery to the peripheral lung, by achieving uniform distribution of drug particles. This systematic review provides a synthesis of current literature concerning the impact of LAMAs on small airways and an insight on LAMAs distribution within the lung.

The Effects of Inhaled Airway Directed Pharmacotherapy on Decline in Lung Function Parameters Among Indigenous Australian Adults With and Without Underlying Airway Disease

BACKGROUND

The trajectory of lung function decline among Indigenous patients with or without underlying chronic airway disease (COPD and concomitant bronchiectasis) and with use of inhaled pharmacotherapy, including inhaled corticosteroids (ICS), has not been reported in the past.

METHODS

Adult Indigenous Australian patients identified to have undergone at least two or more lung function tests (LFTs) between 2012 and 2020 were assessed for changes in the lung function parameters (LFPs) between the first and last recorded LFTs.

RESULTS

Of the total 1350 patients identified to have undergone LFTs, 965 were assessed to fulfil session quality, 115 (n=58 females) were eligible to be included with two or more LFTs. Among the 115 patients, 49% showed radiological evidence of airway diseases, and 77% were on airway directed inhaled pharmacotherapy. Median time between LFTs was 1.5 years (IQR 0.86,5.85), with no significant differences in LFPs noted between first and last LFT. Overall rate of change (mL/year) showed considerable variation for FVC (median -37.55 mL/year [IQR -159.88,92.67]) and FEV1 (-18.74 mL/year [-102.49,71.44]) with minimal change in FEV1/FVC (0.00 ratio/year [-0.03,0.01]). When stratified by inhaled pharmacotherapy group, however, patients using ICS showed significantly greater rate of FEV1 decline (-48.64 mL/year [-110.18,62.5]) compared to those using pharmacotherapy with no ICS (15.46 mL/year [-73.5,74.62]) and those using no pharmacotherapy (-5.76 mL/year [-63.19,67.34]) (p=0.022). Additionally, a greater proportion of these patients reached the threshold for excessive FEV1 decline (64%) compared to those using pharmacotherapy without ICS (44%) and those using no pharmacotherapy (52%).

CONCLUSION

Decline in LFPs occurs commonly among adult Indigenous population, especially, excessive so among those using inhaled pharmacotherapy containing ICS.

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.

Budesonide/Glycopyrrolate/Formoterol Fumarate Co-suspension Metered Dose Inhaler: A Triple Therapy for the Treatment of Chronic Obstructive Pulmonary Disease

OBJECTIVE

To review current evidence on the use of a fixed-dose combination (FDC) of budesonide/glycopyrrolate/formoterol fumarate (BGFF) triple therapy delivered via metered dose inhaler (MDI) in patients with chronic obstructive pulmonary disease (COPD) and offer clinical practice insights.

DATA SOURCES

We used PubMed to conduct the literature search from 1946 through June 30, 2021, using budesonide, glycopyrrolate or glycopyrronium, and formoterol.

STUDY SELECTION AND EXTRACTION

We included clinical trials in patients with COPD along with pharmacokinetic or pharmacodynamic studies.

DATA SYNTHESIS

In all, 19 citations were included. BGFF MDI reduces the risk of exacerbations regardless of exacerbation history compared with dual bronchodilators or inhaled corticosteroid/long-acting β-agonist. Rescue inhaler use decreased, and patient-reported outcomes of symptoms and well-being improved with triple therapy. Mortality was decreased with the higher-dose BGFF MDI in comparison to dual bronchodilator therapy. Dysphonia and candidiasis were more common with BGFF MDI compared with dual bronchodilators, as was pneumonia.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

BGFF MDI is the second FDC triple therapy approved for COPD treatment. BGFF MDI improves important patient outcomes in COPD, including exacerbation risk. The unique co-suspension technology allows delivery of 3 active ingredients in 1 inhaler, a potential benefit to overcome adherence and technique-related barriers. These benefits must be gently weighed against the increased risk of pneumonia.

CONCLUSION

The findings from phase 3 trials support the efficacy and safety of triple therapy in COPD. Future studies are needed to confirm potential mortality benefit and the role of triple therapy in patients without an exacerbation history.

Seven Pillars of Small Airways Disease in Asthma and COPD: Supporting Opportunities for Novel Therapies

Identification of pathologic changes in early and mild obstructive lung disease has shown the importance of the small airways and their contribution to symptoms. Indeed, significant small airways dysfunction has been found prior to any overt airway obstruction being detectable by conventional spirometry techniques. However, most therapies for the treatment of obstructive lung disease target the physiological changes and associated symptoms that result from chronic lung disease, rather than directly targeting the specific underlying causes of airflow disruption or the drivers of disease progression. In addition, although spirometry is the current standard for diagnosis and monitoring of response to therapy, the most widely used measure, FEV1 , does not align with the pathologic changes in early or mild disease and may not align with symptoms or exacerbation frequency in the individual patient. Newer functional and imaging techniques allow more effective assessment of small airways dysfunction; however, significant gaps in our understanding remain. Improving our knowledge of the role of small airways dysfunction in early disease in the airways, along with the identification of novel end points to measure subclinical changes in this region (ie, those not captured as symptoms or identified through standard FEV1), may lead to the development of novel therapies that directly combat early airways disease processes with a view to slowing disease progression and reversing damage. This expert opinion paper discusses small airways disease in the context of asthma and COPD and highlights gaps in current knowledge that impede earlier identification of obstructive lung disease and the development and standardization of novel small airways-specific end points for use in clinical trials.

Small airways in asthma: from bench-to-bedside

INTRODUCTION

Historically, asthma was considered a disease predominantly of the large airways, but gradually small airways have been recognized as the major site of airflow obstruction. Small airway dysfunction (SAD) significantly contributes to the pathophysiology of asthma and it is present across all asthma severities. Promising pre-clinical findings documented enhanced beneficial effects of combination therapies on small airways compared to monocomponents, thus it was questioned whether this could translate into further clinical implications from bench-to-bedside. The aim of this review was to systematically assess the state of the art of small airway involvement in asthma, especially in response to different pharmacological treatments acting on the respiratory system.

EVIDENCE ACQUISITION

A comprehensive literature search was performed in MEDLINE for randomized controlled trials (RCTs) characterizing the impact on small airways of different pharmacological treatments acting on the respiratory system. The results were extracted and reported via qualitative synthesis.

EVIDENCE SYNTHESIS

Overall, 63 studies were identified from the literature search, whereas 23 RCTs met the inclusion criteria. Evidence confirms that both drug particle size and the type of inhalation devices represent two of the most important variables for an effective peripheral lung distribution.

CONCLUSIONS

Despite the numerous methodological tools to detect SAD, there is still no gold standard diagnostic method to assess small airways, especially in severe asthma. Further research should be directed to improve primary and secondary prevention strategies by supporting the combined approach of different non-invasive techniques for an early detection of peripheral abnormalities and optimization of asthma therapy.

Structural and functional development in airways throughout childhood: Children are not small adults

Children are not small adults and this fact is particularly true when we consider the respiratory tract. The anatomic peculiarities of the upper airway make infants preferential nasal breathers between 2 and 6 months of life. The pediatric larynx has a more complex shape than previously believed, with the narrowest point located anatomically at the subglottic level and functionally at the cricoid cartilage. Alveolarization of the distal airways starts conventionally at 36-37 weeks of gestation, but occurs mainly after birth, continuing until adolescence. The pediatric chest wall has unique features that are particularly pronounced in infants. Neonates, infants, and toddlers have a higher metabolic rate, and consequently, their oxygen consumption at rest is more than double that of adults. The main anatomical and functional differences between pediatric and adult airways contribute to the understanding of various respiratory symptoms and disease conditions in childhood. Knowing the peculiarities of pediatric airways is helpful in the prevention, management, and treatment of acute and chronic diseases of the respiratory tract. Developmental modifications in the structure of the respiratory tract, in addition to immunological and neurological maturation, should be taken into consideration during childhood.

Airway Deposition of Extrafine Inhaled Triple Therapy in Patients with COPD: A Model Approach Based on Functional Respiratory Imaging Computer Simulations

Introduction

There is a clear correlation between small airways dysfunction and poor clinical outcomes in patients with chronic obstructive pulmonary disease (COPD), and it is therefore important that inhalation therapy (both bronchodilator and anti-inflammatory) can deposit in the small airways. Two single-inhaler triple therapy (SITT) combinations are currently approved for the maintenance treatment of COPD: extrafine formulation beclomethasone dipropionate/formoterol fumarate/glycopyrronium bromide (BDP/FF/GB), and non-extrafine formulation fluticasone furoate/vilanterol/umeclidinium (FluF/VI/UMEC). This study evaluated the lung deposition of the inhaled corticosteroid (ICS), long-acting β₂-agonist (LABA), and long-acting muscarinic antagonist (LAMA) components of these two SITTs.

Materials and Methods

Lung deposition was estimated in-silico using functional respiratory imaging, a validated technique that uses aerosol delivery performance profiles, patients’ high-resolution computed tomography (HRCT) lung scans, and patient-derived inhalation profiles to simulate aerosol lung deposition.

Results

HRCT scan data from 20 patients with COPD were included in these analyses, who had post-bronchodilator forced expiratory volume in 1 second (FEV₁) ranging from 19.3% to 66.0% predicted. For intrathoracic deposition (as a percentage of the emitted dose), deposition of the ICS component was higher from BDP/FF/GB than FluF/VI/UMEC; the two triple therapies had similar performance for both the LABA component and the LAMA component. Peripheral deposition of all three components was higher with BDP/FF/GB than FluF/VI/UMEC. Furthermore, the ratios of central to peripheral deposition for all three components of BDP/FF/GB were <1, indicating greater peripheral than central deposition (0.48±0.13, 0.48±0.13 and 0.49±0.13 for BDP, FF and GB, respectively; 1.96±0.84, 0.97±0.34 and 1.20±0.48 for FluF, VI and UMEC, respectively).

Conclusions

Peripheral (small airways) deposition of all three components (ICS, LABA, and LAMA) was higher from BDP/FF/GB than from FluF/VI/UMEC, based on profiles from patients with moderate to very severe COPD. This is consistent with the extrafine formulation of BDP/FF/GB.

Small airways' function in Obstructive Sleep Apnea-Hypopnea Syndrome

INTRODUCTION AND OBJECTIVES

Most of the studies of the pathophysiology of Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) focus on the collapsibility and obstruction of the upper airways. The aim of our study was the investigation of small airways' function in patients with OSAHS.

MATERIALS AND METHODS

We studied 23 patients (mean age, 51.6 years) diagnosed with mild to severe OSAHS, without comorbidities and 8 controls (mean age, 45.9 years). All subjects underwent full polysomnography sleep study; spirometry and maximum flow/volume curves while breathing room air and a mixture of 80%He-20%O₂. The volume of equal flows (VisoV⋅) of the two curves and the difference of flows at 50% of FVC (ΔV˙max₅₀) were calculated, as indicates of small airways' function.

RESULTS

The results showed that VisoV⋅ was significantly increased in patients with OSAHS compared with controls (18.79±9.39 vs. 4.72±4.68, p=0.004). No statistically significantly difference was found in ΔV˙_max50% (p=0.551); or the maximum Expiratory flow at 25-75% of FVC (p=0.067) and the maximum expiratory flow at 50% of FVC (p=0.174) breathing air.

CONCLUSIONS

We conclude that at the time of the diagnosis of OSAHS, the function of the small airways is affected. This could be due to breathing at low lung volumes and the cyclic closure/opening of the small airways and may affect the natural history of OSAHS. The findings could lead to new therapeutic implications, targeting directly the small airways.

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.

Effect of Poly(vinyl alcohol) on Nanoencapsulation of Budesonide in Chitosan Nanoparticles via Ionic Gelation and Its Improved Bioavailability

Chitosan (CS) is a polymer extensively used in drug delivery formulations mainly due to its biocompatibility and low toxicity. In the present study, chitosan was used for nanoencapsulation of a budesonide (BUD) drug via the well-established ionic gelation technique and a slight modification of it, using also poly(vinyl alcohol) (PVA) as a surfactant. Scanning electron microscopy (SEM) micrographs revealed that spherical nanoparticles were successfully prepared with average sizes range between 363 and 543 nm, as were measured by dynamic light scattering (DLS), while zeta potential verified their positive charged surface. X-ray diffraction (XRD) patterns revealed that BUD was encapsulated in crystalline state in nanoparticles but with a lower degree of crystallinity than the neat drug, which was also proven by differential scanning calorimetry (DSC) and melting peak measurements. This could be attributed to interactions that take place between BUD and CS, which were revealed by FTIR and by an extended computational study. An in vitro release study of budesonide showed a slight enhancement in the BUD dissolution profile, compared to the neat drug. However, drug release was substantially increased by introducing PVA during the nanoencapsulation procedure, which is attributed to the higher amorphization of BUD on these nanoparticles. The release curves were analyzed using a diffusion model that allows estimation of BUD diffusivity in the nanoparticles.

Inhaled aerosol dose distribution between proximal bronchi and lung periphery

Modern inhaled drug discovery programs assess dose delivery to proximal and distal airways using rudimentary imaging indices, where relative deposition is estimated by generically defined 'central' and 'peripheral' lung regions. Utilizing recent data linking the proximal airway topology to a characteristic pattern of aerosol lung deposition, we provide a direct measure of dose distribution between the proximal bronchi and the distal lung. We analyzed scintigraphic lung images of twelve asthma patients following inhalation of 1.5-, 3- and 6-µm monodisperse drug particles at breathing flows of 30- and 60-L/min. We explicitly used the central hot-spots associated with each patient's specific bronchial topology to obtain a direct measure of aerosol deposition in the proximal bronchi, rather than applying standard templates of lung boundaries. Maximum deposition in the central bronchi (as % of lung deposition) was 52 ± 10(SD)% (6 µm;60 L/min). Minimum central deposition was 17 ± 2(SD)% (1.5 µm;30 L/min) where the 83% aerosol 'escaping' deposition in the central bronchi reached 75 ± 17(SD)% of the lung area that could be reached by Krypton gas. For all particle sizes, hot-spots appeared in the same patient-specific central airway location, with greatest intensity at 60 L/min. For a range of respirable aerosol sizes and breathing flows, we have quantified deposited dose in the proximal bronchi and their distal lung reach, constituting a platform to support therapeutic inhaled aerosol drug development.

Inhalation therapy devices for the treatment of obstructive lung diseases: the history of inhalers towards the ideal inhaler

Inhalation therapy allows conveying drugs directly into the airways. The devices used to administer inhaled drugs play a crucial role in the management of obstructive lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). To ensure high bronchial deposition of the drug, a device should deliver a high proportion of fine particles, be easy to use, and provide constant and accurate doses of the active substance. Nowadays, four different types of inhalers are widely used: nebulizers, dry powder inhalers (DPIs), pressurized metered-dose inhalers (pMDIs), and soft mist inhalers (SMIs). Nebulizers can be used by patients unable to use other inhalers. However, they require long times of administration and do not ensure precise dosages. The first pMDIs became popular since they were small, inexpensive, fast, and silent. Their performance was improved by spacers and then by new technologies which reduced the delivery speed. In DPIs, micronized drug particles are attached to larger lactose carrier particles. No coordination between actuation and inhalation is required. However, the patient is supposed to produce an adequate inspiratory flow to extract the drug and disaggregate it from the carrier. In SMIs, the medication is dissolved in an aqueous solution, without propellant, and it is dispensed as a slow aerosol cloud thanks to the energy of a spring. Smart inhalers, connected to smartphones, are promising tools that can provide information about patient's adherence and their inhaler technique. Inhalation has also been proposed as a route of administration for several systemic drugs.

Optimal Connection for Tiotropium SMI Delivery through Mechanical Ventilation: An In Vitro Study

We aimed to quantify Soft Mist Inhalers (SMI) delivery to spontaneous breathing model and compare with different adapters via endotracheal tube during mechanical ventilation or by manual resuscitation. A tiotropium SMI was used with a commercial in-line adapter and a T-adapter placed between the Y-adapter and the inspiratory limb of the ventilator circuit during mechanical ventilation. The SMI was actuated at the beginning of inspiration and expiration. In separate experiments, a manual resuscitator with T-adapter was attached to endotracheal tube, collecting filter, and a passive test lung. Drug was eluted from collecting filters with salt-based solvent and analyzed using high-performance liquid chromatography. Results showed the percent of SMI label dose inhaled was 3-fold higher with the commercial in-line adapter with actuation during expiration than when synchronized with inspiration. SMI with T-adapter delivery via ventilator was similar to inhalation (1.20%) or exhalation (1.02%), and both had lower delivery dose than with manual resuscitator (2.80%; p = 0.01). The inhaled dose via endotracheal tube was much lower than inhaled dose with spontaneous breathing (22.08%). In conclusion, the inhaled dose with the commercial adapter was higher with SMI actuated during expiration, but still far less than reported spontaneous inhaled dose.

Pharmacokinetics, pharmacodynamics and safety of a novel extrafine BDP/FF/GB combination delivered via metered-dose inhaler in healthy Chinese subjects

BACKGROUND

BDP/FF/GB pMDI is a novel triple fixed-dose combination of extra-fine inhalation aerosol beclomethasone dipropionate (BDP)/formoterol fumarate (FF)/glycopyrronium bromide (GB). Limited data on the pharmacokinetic (PK) and pharmacodynamic (PD) properties of BDP/FF/GB fixed-dose combination in healthy subjects was available.

PURPOSES

This study aimed to evaluate the pharmacokinetics, pharmacodynamics and safety of BDP/FF/GB pMDI in healthy Chinese subjects.

METHODS

This is an open-label, parallel-group, randomized, single and multiple dose study. In the single dose group, subjects received single supra-therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 400/24/50 µg). In the multiple dose group, subjects received therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 200/12/25 µg), twice daily, for 7 consecutive days. Plasma BDP, B17MP, formoterol and GB were determined by a validated ultra performance liquid chromatography method with tandem mass spectrometric detection (UPLC/MS-MS). Heart rate (HR), QTcF, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were evaluated as the surrogate indicators of pharmacodynamic effects.

RESULTS

A total of 24 subjects were randomized and 22 (11 in each group) completed the study. The dose adjusted pharmacokinetic profiles of BDP, beclomethasone-17-monopropionate (B17MP, the most active metabolite of BDP), formoterol and GB were overall similar in therapeutic and supra- therapeutic dose group, showing dose proportional increase of the systemic exposure to BDP, B17MP, formoterol and GB. The pharmacodynamic variables were within the normal range and showed no significant difference between the two groups. All the treatment-emergent adverse events (TEAEs) were mild and no severe TEAE was reported.

CONCLUSIONS

Dose adjusted PK profiles were similar between therapeutic and supra-therapeutic dose for all compounds, nearly dose proportional systemic exposure to B17MP, formoterol and GB after BDP/FF/GB pMDI administration in healthy Chinese subjects. BDP/FF/GB pMDI was safe and well tolerated in healthy Chinese subjects. The PK profiles were comparable to previously published data from Western European healthy Caucasian subjects.

COPD Exacerbations: A Patient and Physician's Perspective

This article, co-authored by a patient affected by chronic obstructive pulmonary disease (COPD) and a respiratory specialist, discusses the patient’s experience of living with the disease and, in particular, the impact of COPD exacerbations on his life. The physician discusses the clinical approach to COPD exacerbations. Together, they provide a call to action to improve the management of COPD exacerbations.

Funding AstraZeneca.

Recent Advances in Inflammation and Treatment of Small Airways in Asthma

Small airways were historically considered to be almost irrelevant in the development and control of pulmonary chronic diseases but, as a matter of fact, in the past few years we have learned that they are not so "silent". Asthma is still a worldwide health issue due to the great share of patients being far from optimal management. Several studies have shown that the deeper lung inflammation plays a critical role in asthma pathogenesis, mostly in these not well-controlled subjects. Therefore, assessing the degree of small airways inflammation and impairment appears to be a pivotal step in the asthmatic patient's management. It is now possible to evaluate them through direct and indirect measurements, even if some obstacles still affect their clinical application. The success of any treatment obviously depends on several factors but reaching the deeper lung has become a priority and, for inhaled drugs, this is strictly connected to the molecule's size. The aim of the present review is to summarize the recent evidence concerning the small airway involvement in asthma, its physiopathological characteristics and how it can be evaluated in order to undertake a personalized pharmacological treatment and achieve a better disease control.

Choosing the right inhaler for your asthma or COPD patient

Appropriate selection and correct use of inhalation devices is an integral component in the management of asthma and chronic obstructive pulmonary disease (COPD). It is well known that there are many challenges with the use of inhalers, and no one device suits all patients. Challenges can range from difficulties related to lung disease severity and pulmonary function to physical considerations, including manual dexterity and comorbidities such as arthritis. In terms of device selection and adherence, patient engagement and satisfaction are also important factors to consider. Furthermore, problems with inhaler use can be most evident in children and older patients. Here, we discuss aspects for consideration with commonly used devices, including nebulizers, pressurized metered-dose inhalers, dry powder inhalers, and the soft mist inhaler. As each inhaler offers varying technical properties, a tailored and personalized approach to the selection of the most appropriate device for the patient is highly recommended in order to increase the likelihood of achieving improved disease outcomes and enhance persistence with device adherence. Importantly, education and support is crucial, not only to enable patients to recognize the need for optimal disease management, but also to help them develop good inhaler technique. In addition, health care professionals should also aim to increase their knowledge of the devices they prescribe, and develop systems to ensure that they offer comprehensive support to patients in clinical practice. Considering these aspects, this review discusses potential strategies to help address the challenges of inhaler use in asthma and COPD.

Associations of AMP and adenosine induced dyspnea sensation to large and small airways dysfunction in asthma

Background

Bronchial provocation is often used to confirm asthma. Dyspnea sensation, however, associates poorly with the evoked drop in FEV₁. Provocation tests only use the large airways parameter FEV₁, although dyspnea is associated with both large- and small airways dysfunction. Aim of this study was to explore if adenosine 5′-monophosphate (AMP) and adenosine evoke an equal dyspnea sensation and if dyspnea associates better with large or small airways dysfunction.

Methods

We targeted large airways with AMP and small airways with dry powder adenosine in 59 asthmatic (ex)-smokers with ≥5 packyears, 14 ± 7 days apart. All subjects performed spirometry, impulse oscillometry (IOS), and Borg dyspnea score. In 36 subjects multiple breath nitrogen washout (MBNW) was additionally performed. We analyzed the association of the change (Δ) in Borg score with the change in large and small airways parameters, using univariate and multivariate linear regression analyses. MBNW was analyzed separately.

Results

Provocation with AMP and adenosine evoked similar levels of dyspnea. ΔFEV₁ was not significantly associated with ΔBorg after either AMP or adenosine provocation, in both univariate and multivariate analyses. In multivariate linear regression, a decrease in FEF_25–75 during adenosine provocation was independently associated with an increase in Borg. In the multivariate analyses for AMP provocation, no significant associations were found between ΔBorg and any large or small airways parameters.

Conclusion

AMP and adenosine induce equally severe dyspnea sensations. Our results suggest that dyspnea induced with dry powder adenosine is related to small airways involvement, while neither large nor small airways dysfunction was associated with AMP-induced dyspnea.

Trail registration

NCT01741285 at www.clinicaltrials.gov, first registered Dec 4th, 2012.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0783-0) contains supplementary material, which is available to authorized users.

Use of computational fluid dynamics deposition modeling in respiratory drug delivery

INTRODUCTION

Respiratory drug delivery is a surprisingly complex process with a number of physical and biological challenges. Computational fluid dynamics (CFD) is a scientific simulation technique that is capable of providing spatially and temporally resolved predictions of many aspects related to respiratory drug delivery from initial aerosol formation through respiratory cellular drug absorption.

AREAS COVERED

This review article focuses on CFD-based deposition modeling applied to pharmaceutical aerosols. Areas covered include the development of new complete-airway CFD deposition models and the application of these models to develop a next-generation of respiratory drug delivery strategies.

EXPERT OPINION

Complete-airway deposition modeling is a valuable research tool that can improve our understanding of pharmaceutical aerosol delivery and is already supporting medical hypotheses, such as the expected under-treatment of the small airways in asthma. These complete-airway models are also being used to advance next-generation aerosol delivery strategies, like controlled condensational growth. We envision future applications of CFD deposition modeling to reduce the need for human subject testing in developing new devices and formulations, to help establish bioequivalence for the accelerated approval of generic inhalers, and to provide valuable new insights related to drug dissolution and clearance leading to microdosimetry maps of drug absorption.

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.

Gamma scintigraphic pulmonary deposition study of glycopyrronium/formoterol metered dose inhaler formulated using co-suspension delivery technology

This gamma scintigraphy imaging study was the first to assess pulmonary and extrathoracic deposition and regional lung deposition patterns of a radiolabelled long-acting muscarinic antagonist/long-acting β₂-agonist fixed-dose combination glycopyrronium/formoterol fumarate dihydrate (GFF) 14.4/10μg (equivalent to glycopyrrolate/formoterol fumarate 18/9.6μg), delivered by pressurized metered dose inhaler (pMDI) using novel co-suspension delivery technology. In this Phase I, randomized, single-centre, single-blind, single-dose, two-treatment, crossover, placebo-controlled study (PT003020), 10 healthy male adults received two actuations of GFF pMDI (7.2/5.0μg per actuation) and placebo pMDI (containing phospholipid-based porous particles without active pharmaceutical ingredient), both radiolabelled with ^99mTc, up to 5MBq per actuation. Gamma scintigraphy images of lungs, stomach, head and neck were recorded. In addition, images of the actuators after use, collected mouth washings and exhalation filters were acquired. On average, 38.4% of the emitted dose of radiolabelled GFF pMDI, and 32.8% of radiolabelled placebo pMDI, was deposited in the lungs. The percentage emitted dose detected in the oropharyngeal and stomach regions was 61.4% and 66.9% for radiolabelled GFF pMDI and placebo pMDI, respectively. For both treatments, ≤0.25% of the emitted dose was detected in the exhalation filter. The normalized outer/inner ratio was 0.57 and 0.59 for radiolabelled GFF pMDI and placebo pMDI, respectively, and the standardized central/peripheral ratio was 1.85 and 1.94 respectively, indicating delivery of both co-suspension delivery technology formulations throughout the airways. There were no new or unexpected safety findings. In conclusion, both formulations were efficiently and uniformly deposited in the lungs with similar regional deposition patterns, oropharyngeal and stomach deposition, exhalation fraction and actuator-recovered dose.

Triple therapy in COPD: new evidence with the extrafine fixed combination of beclomethasone dipropionate, formoterol fumarate, and glycopyrronium bromide

The goals of COPD therapy are to prevent and control symptoms, reduce the frequency and severity of exacerbations, and improve exercise tolerance. The triple combination therapy of inhaled corticosteroids (ICSs), long-acting beta₂ agonists (LABAs), and long-acting muscarinic antagonists (LAMAs) has become an option for maintenance treatment of COPD and as a “step-up” therapy from single or double combination treatments. There is evidence that triple combination ICS/LABA/LAMA with different inhalers improves lung function, symptoms, and health status and reduces exacerbations. A new triple fixed-dose combination of extrafine beclomethasone dipropionate (100 µg/puff)/formoterol fumarate (6 µg/puff)/glycopyrronium bromide (12.5 µg/puff) has been developed as a hydrofluoroalkane pressurized metered dose inhaler. Two large pivotal studies showed that this extrafine fixed ICS/LABA/LAMA triple combination is superior to fixed ICS/LABA combined therapy and also superior to the LAMA tiotropium in terms of lung function and exacerbation prevention in COPD patients at risk of exacerbation. This review considers the new information provided by these clinical trials of extrafine triple therapy and the implications for the clinical management of COPD patients.

Small Airway Absorption and Microdosimetry of Inhaled Corticosteroid Particles after Deposition

PURPOSE

To predict the cellular-level epithelial absorbed dose from deposited inhaled corticosteroid (ICS) particles in a model of an expanding and contracting small airway segment for different particle forms.

METHODS

A computational fluid dynamics (CFD)-based model of drug dissolution, absorption and clearance occurring in the surface liquid of a representative small airway generation (G13) was developed and used to evaluate epithelial dose for the same deposited drug mass of conventional microparticles, nanoaggregates and a true nanoaerosol. The ICS medications considered were budesonide (BD) and fluticasone propionate (FP). Within G13, total epithelial absorption efficiency (AE) and dose uniformity (microdosimetry) were evaluated.

RESULTS

Conventional microparticles resulted in very poor AE of FP (0.37%) and highly nonuniform epithelial absorption, such that <5% of cells received drug. Nanoaggregates improved AE of FP by a factor of 57-fold and improved dose delivery to reach approximately 40% of epithelial cells. True nanoaerosol resulted in near 100% AE for both drugs and more uniform drug delivery to all cells.

CONCLUSIONS

Current ICS therapies are absorbed by respiratory epithelial cells in a highly nonuniform manner that may partially explain poor clinical performance in the small airways. Both nanoaggregates and nanoaerosols can significantly improve ICS absorption efficiency and uniformity.

Extrafine compared to non-extrafine particle inhaled corticosteroids in smokers and ex-smokers with asthma

BACKGROUND

Smoking is as prevalent in asthmatics as in the general population. Asthmatic smokers benefit less from inhaled corticosteroids (ICS) than non-smoking asthmatics, possibly due to more smoking-induced small airways disease. Thus targeting small airways may be important in treating asthmatic (ex-)smokers. We hypothesized that extrafine particle ICS improve small airways function more than non-extrafine particle ICS in asthmatic (ex-)smokers.

METHODS

We performed an open-label, randomized, three-way cross-over study comparing extrafine beclomethasone (HFA-QVAR) to non-extrafine beclomethasone (HFA-Clenil) and fluticasone (HFA-Flixotide) in 22 smokers and 21 ex-smokers with asthma (?5 packyears).

RESULTS

Improvement from baseline in PD₂₀ adenosine after using QVAR, Clenil or Flixotide was 1.04 ± 1.71, 1.09 ± 2.12 and 0.94 ± 1.97 doubling doses, mean ± standard deviation (SD), respectively. The change from baseline in R₅-R₂₀ at PD₂₀ adenosine after using QVAR, Clenil or Flixotide was ?0.02 ± 0.27, 0.02 ± 0.21, and ?0.02 ± 0.31 kPa sL^?1, mean ± SD, respectively. The change in PD₂₀ adenosine and R₅-R₂₀ at PD₂₀ adenosine were neither statistically significant different between QVAR and Clenil (p = 0.86 and p = 0.82) nor between QVAR and Flixotide (p = 0.50 and p = 0.96).

CONCLUSION

Similar effectiveness in improving small airways function was found for extrafine and non-extrafine particle ICS treatment for asthmatic smokers and ex-smokers.

Recent advances in capsule-based dry powder inhaler technology

Pulmonary drug delivery is currently the focus of accelerated research and development because of the potential to produce maximum therapeutic benefit to patients by directly targeting drug to the site of pathology in the lungs. Among the available delivery options, the dry powder inhaler (DPI) is the preferred device for the treatment of an increasingly diverse range of diseases. However, because drug delivery from a DPI involves a complex interaction between the device and the patient, the engineering development of this medical technology is proving to be a great challenge. Development of DPI systems that target the delivery of fine drug particles to the deeper airways in the lungs using a combination of improved drug formulations and enhanced delivery device technologies means that each of these factors contributes to overall performance of the aerosol system. There are a large range of devices that are currently available, or under development, for clinical use, however no individual device shows superior clinical efficacy. A major concern that is very relevant in day-to-day clinical practice is the inter- and intra-patient variability of the drug dosage delivered to the deep lungs from the inhalation devices, where the extent of variability depends on the drug formulation, the device design, and the patient’s inhalation profile. This variability may result in under-dosing of drug to the patient and potential loss of pharmacological efficacy. This article reviews recent advances in capsule-based DPI technology and the introduction of the ‘disposable’ DPI device.

Manifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA2LEN)

Evidence that enables us to identify, assess, and access the small airways in asthma and chronic obstructive pulmonary disease (COPD) has led INTERASMA (Global Asthma Association) and WAO to take a position on the role of the small airways in these diseases.

Starting from an extensive literature review, both organizations developed, discussed, and approved the manifesto, which was subsequently approved and endorsed by the chairs of ARIA and GA²LEN. The manifesto describes the evidence gathered to date and defines and proposes issues on small airway involvement and management in asthma and COPD with the aim of challenging assumptions, fostering commitment, and bringing about change.

The small airways (defined as those with an internal diameter <2 mm) are involved in the pathogenesis of asthma and COPD and are the major determinant of airflow obstruction in these diseases. Various tests are available for the assessment of the small airways, and their results must be integrated to confirm a diagnosis of small airway dysfunction.

In asthma and COPD, the small airways play a key role in attempts to achieve disease control and better outcomes. Small-particle inhaled formulations (defined as those that, owing to their size [usually <2 μm], ensure more extensive deposition in the lung periphery than large molecules) have proved beneficial in patients with asthma and COPD, especially those in whom small airway involvement is predominant.

Functional and biological tools capable of accurately assessing the lung periphery and more intensive use of currently available tools are necessary. In patients with suspected COPD or asthma, small airway involvement must be assessed using currently available tools. In patients with subotpimal disease control and/or functional or biological signs of disease activity, the role of small airway involvement should be assessed and treatment tailored. Therefore, the choice between large- and small-particle inhaled formulations must reflect the physician’s considerations of disease features, phenotype, and response to previous therapy.

This article is being co-published in Asthma Research and Practice and the World Allergy Organization Journal.

Manifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA2LEN)

Evidence that enables us to identify, assess, and access the small airways in asthma and chronic obstructive pulmonary disease (COPD) has led INTERASMA (Global Asthma Association) and WAO to take a position on the role of the small airways in these diseases.

Starting from an extensive literature review, both organizations developed, discussed, and approved the manifesto, which was subsequently approved and endorsed by the chairs of ARIA and GA²LEN. The manifesto describes the evidence gathered to date and defines and proposes issues on small airway involvement and management in asthma and COPD with the aim of challenging assumptions, fostering commitment, and bringing about change.

The small airways (defined as those with an internal diameter <2 mm) are involved in the pathogenesis of asthma and COPD and are the major determinant of airflow obstruction in these diseases. Various tests are available for the assessment of the small airways, and their results must be integrated to confirm a diagnosis of small airway dysfunction.

In asthma and COPD, the small airways play a key role in attempts to achieve disease control and better outcomes. Small-particle inhaled formulations (defined as those that, owing to their size [usually <2 μm], ensure more extensive deposition in the lung periphery than large molecules) have proved beneficial in patients with asthma and COPD, especially those in whom small airway involvement is predominant.

Functional and biological tools capable of accurately assessing the lung periphery and more intensive use of currently available tools are necessary. In patients with suspected COPD or asthma, small airway involvement must be assessed using currently available tools. In patients with subotpimal disease control and/or functional or biological signs of disease activity, the role of small airway involvement should be assessed and treatment tailored. Therefore, the choice between large- and small-particle inhaled formulations must reflect the physician’s considerations of disease features, phenotype, and response to previous therapy. This article is being co-published in Asthma Research and Practice and the World Allergy Organization Journal.

Study on small airway function in asthmatics with fractional exhaled nitric oxide and impulse oscillometry

OBJECTIVES

The invasive techniques can be direct and objective to assess small airway function, but they have significant risks and inconveniences for patients and cannot be repeated often. Some sophisticated techniques such as fractional exhaled nitric oxide (FeNO) and impulse oscillometry (IOS) may surmount such restrictions. Therefore, we investigated the relation among FeNO, IOS, and small airway function in asthmatic patients.

METHODS

We recruited 140 asthmatic patients including 69 patients with small airway normal function and 71 patients with small airway dysfunction. FeNO, eosinophil（EOS）count and total immunoglobulin E (IgE) in peripheral blood, pulmonary function, as well as IOS were measured.

RESULTS

The levels of FeNO, the reactance area (AX), the resonant frequency Fres and EOS were significantly increased in small airway dysfunction group compared with small airway normal function group (P < 0.01 respectively). A multiple regression model showed that FeNO, AX and Fres were correlative factors of mid forced expiratory flow of percentages of predicted values [FEF25-75 (%pred)] (P < 0.01, respectively). A receiver operating characteristic (ROC) analysis showed that the combination of FeNO, AX and Fres had a greater area under the ROC curve (AUC) than each of them (AUC: 0.881, P < .001, 95％CI: 0.815-0.929).

CONCLUSION

FeNO and IOS are helpful in diagnosis of small airway dysfunction with high sensitivity and specificity, and FeNO combined with IOS can better evaluate the small airway function in asthmatic patients.

Patients' perspectives and preferences in the choice of inhalers: the case for Respimat(®) or HandiHaler(®)

Poor inhaler technique hampers the efficacy of drug therapy in asthma and chronic obstructive pulmonary disease. Not only does this affect individual patient care, but it also impacts on the wider health care economics associated with these conditions. Treatment guidelines recommend a systematic approach to drug class selection; however, standardization of inhaler selection is currently difficult owing to the complexity of the interaction between the inhaler device and the patient. Specifically, individual patient preference can influence how successful a treatment is overall. This article reviews inhaler devices from the patient perspective, with a particular focus on the dry powder inhaler HandiHaler(®) and Respimat(®) Soft Mist™ Inhaler. It discusses factors that influence device preference and treatment compliance and reviews tools that can aid health care professionals to better match inhaler devices to individual patients' needs.

Dilemmas, Confusion, and Misconceptions Related to Small Airways Directed Therapy

During the past decade, there has been increasing evidence that the small airways (ie, airways < 2 mm in internal diameter) contribute substantially to the pathophysiologic and clinical expression of asthma and COPD. The increased interest in small airways is, at least in part, a result of innovation in small-particle aerosol formulations that better target the distal lung and also advanced physiologic methods of assessing small airway responses. Increasing the precision of drug deposition may improve targeting of specific diseases or receptor locations, decrease airway drug exposure and adverse effects, and thereby increase the efficiency and effectiveness of inhaled drug delivery. The availability of small-particle aerosols of corticosteroids, bronchodilators, or their combination enables a higher total lung deposition and better peripheral lung penetration and provides added clinical benefit, compared with large-particle aerosol treatment. However, a number of questions remain unanswered about the pragmatic approach relevant for clinicians to consider the role of small airways directed therapy in the day-to-day management of asthma and COPD. We thus have tried to clarify the dilemmas, confusion, and misconceptions related to small airways directed therapy. To this end, we have reviewed all studies on small-particle aerosol therapy systematically to address the dilemmas, confusion, and misconceptions related to small airways directed therapy.

The prevalence of small airways disease in adult asthma: A systematic literature review

BACKGROUND

Small airways dysfunction and inflammation contribute significantly to the clinical impact of asthma, yet conventional methods of assessing airways function in the clinic cannot reliably evaluate its presence. However, most recently, promising methods of assessment are being utilised.

METHODS

We conducted a systematic literature review, using PubMed, with the aim of determining the prevalence of small airways disease in adult patients with asthma. We ascertained how small airways disease prevalence compared between different studies when measured using distinct techniques of small airways assessment.

RESULTS

Fifteen publications were identified determining the prevalence of small airways disease in asthma. Methods of assessments included impulse oscillometry, spirometry, body plethysmography, multiple-breath nitrogen washout, and high-resolution computed tomography. These studies used differing inclusion characteristics and recruited patients with a broad range of asthma severity, yet collectively they reported an overall prevalence of small airways disease of 50-60%. Small airways disease was present across all asthma severities, with evidence of distal airway disease even in the absence of proximal airway obstruction.

CONCLUSIONS

Small airways disease is highly prevalent in asthma, even in patients with milder disease. Given the clinical impact of small airways disease, its presence should not be underestimated or overlooked as part of the daily management of patients with asthma.

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

Development of a new drug for the treatment of lung disease is a complex and time consuming process involving numerous disciplines of basic and applied sciences. During the 2015 Congress of the International Society for Aerosols in Medicine, a group of experts including aerosol scientists, physiologists, modelers, imagers, and clinicians participated in a workshop aiming at bridging the gap between basic research and clinical efficacy of inhaled drugs. This publication summarizes the current consensus on the topic. It begins with a short description of basic concepts of aerosol transport and a discussion on targeting strategies of inhaled aerosols to the lungs. It is followed by a description of both computational and biological lung models, and the use of imaging techniques to determine aerosol deposition distribution (ADD) in the lung. Finally, the importance of ADD to clinical efficacy is discussed. Several gaps were identified between basic science and clinical efficacy. One gap between scientific research aimed at predicting, controlling, and measuring ADD and the clinical use of inhaled aerosols is the considerable challenge of obtaining, in a single study, accurate information describing the optimal lung regions to be targeted, the effectiveness of targeting determined from ADD, and some measure of the drug's effectiveness. Other identified gaps were the language and methodology barriers that exist among disciplines, along with the significant regulatory hurdles that need to be overcome for novel drugs and/or therapies to reach the marketplace and benefit the patient. Despite these gaps, much progress has been made in recent years to improve clinical efficacy of inhaled drugs. Also, the recent efforts by many funding agencies and industry to support multidisciplinary networks including basic science researchers, R&D scientists, and clinicians will go a long way to further reduce the gap between science and clinical efficacy.

Oscillating Positive Expiratory Pressure on Respiratory Resistance in Chronic Obstructive Pulmonary Disease With a Small Amount of Secretion: A Randomized Clinical Trial

This study aims to evaluate the acute effects of an oscillating positive expiratory pressure device (flutter) on airways resistance in patients with chronic obstructive pulmonary disease (COPD).Randomized crossover study: 15 COPD outpatients from Asthma Lab-Royal Brompton Hospital underwent spirometry, impulse oscillometry (IOS) for respiratory resistance (R) and reactance (X), and fraction exhaled nitric oxide (FeNO) measures.Thirty minutes of flutter exercises: a "flutter-sham" procedure was used as a control, and airway responses after a short-acting bronchodilator were also assessed.Respiratory system resistance (R): in COPD patients an increase in X5insp (-0.21 to -0.33 kPa/L/s) and Fres (24.95 to 26.16 Hz) occurred immediately after flutter exercises without bronchodilator. Following 20 min of rest, a decrease in the R5, ΔR5, R20, X5, and Ax was observed, with R5, R20, and X5 values lower than baseline, with a moderate effect size; there were no changes in FeNO levels or spirometry.The use of flutter can decrease the respiratory system resistance and reactance and expiratory flow limitation in stable COPD patients with small amounts of secretions.

Characterization of acinar airspace involvement in asthmatic patients by using inert gas washout and hyperpolarized (3)helium magnetic resonance

BACKGROUND

The multiple-breath inert gas washout parameter acinar ventilation heterogeneity (Sacin) is thought to be a marker of acinar airway involvement but has not been validated by using quantitative imaging techniques in asthmatic patients.

OBJECTIVE

We aimed to use hyperpolarized (3)He diffusion magnetic resonance at multiple diffusion timescales and quantitative computed tomographic (CT) densitometry to determine the nature of acinar airway involvement in asthmatic patients.

METHODS

Thirty-seven patients with asthma and 17 age-matched healthy control subjects underwent spirometry, body plethysmography, multiple-breath inert gas washout (with the tracer gas sulfur hexafluoride), and hyperpolarized (3)He diffusion magnetic resonance. A subset of asthmatic patients (n = 27) underwent quantitative CT densitometry.

RESULTS

Ninety-four percent (16/17) of patients with an increased Sacin had Global Initiative for Asthma treatment step 4 to 5 asthma, and 13 of 17 had refractory disease. The apparent diffusion coefficient (ADC) of (3)He at 1 second was significantly higher in patients with Sacin-high asthma compared with that in healthy control subjects (0.024 vs 0.017, P < .05). Sacin correlated strongly with ADCs at 1 second (R = 0.65, P < .001) but weakly with ADCs at 13 ms (R = 0.38, P < .05). ADCs at both 13 ms and 1 second correlated strongly with the mean lung density expiratory/inspiratory ratio, a CT marker of expiratory air trapping (R = 0.77, P < .0001 for ADCs at 13 ms; R = 0.72, P < .001 for ADCs at 1 second).

CONCLUSION

Sacin is associated with alterations in long-range diffusion within the acinar airways and gas trapping. The precise anatomic nature and mechanistic role in patients with severe asthma requires further evaluation.

Small-airway disease in asthma: pharmacological considerations

PURPOSE OF REVIEW

To review the pharmacological considerations and rationale for treating small-airway disease in asthma via the inhaled and systemic route, and to also directly address the comparison between small vs. large aerosol particles in the management of asthmatic patients.

RECENT FINDINGS

Airway inflammation in patients with asthma is predominantly present within the small airways and this region is the main contributor to airflow limitation. Assessing small-airway dysfunction has advanced in the last decade, allowing us to compare this region in disease to health and also in response to treatment. Recent pharmaceutical developments have led to inhaler devices with smaller aerosols and systemic biologic treatments, enabling therapeutic drug delivery to the distal lung regions. The question therefore is does targeting the small airways directly translate into health benefits for asthmatic patients with respect to an improvement in their disease control and quality of life?

SUMMARY

Studies now show that treating the peripheral airways with smaller drug particle aerosols certainly achieve comparable efficacy (and some studies show superiority) compared with large particles, a reduction in the daily inhaled corticosteroid dose, and greater asthma control and quality of life in real-life studies. Hence, the small airways should not be neglected when choosing the optimal asthma therapy.

Techniques of assessing small airways dysfunction

The small airways are defined as those less than 2 mm in diameter. They are a major site of pathology in many lung diseases, not least chronic obstructive pulmonary disease (COPD) and asthma. The small airways are frequently involved early in the course of these diseases, with significant pathology demonstrable often before the onset of symptoms or changes in spirometry and imaging. Despite their importance, they have proven relatively difficult to study. This is in part due to their relative inaccessibility to biopsy and their small size which makes their imaging difficult. Traditional lung function tests may only become abnormal once there is a significant burden of disease within them. This has led to the term 'the quiet zone' of the lung. In recent years, more specialised tests have been developed which may detect these changes earlier, perhaps offering the possibility of earlier diagnosis and intervention. These tests are now moving from the realms of clinical research laboratories into routine clinical practice and are increasingly useful in the diagnosis and monitoring of respiratory diseases. This article gives an overview of small airways physiology and some of the routine and more advanced tests of airway function.

The association of asthma and atrial fibrillation--a nationwide population-based nested case-control study

BACKGROUND

Asthma and atrial fibrillation (AF) have been reported to be related to an increased risk of cardiovascular events. However, the relationship between asthma and AF has not been fully elucidated. The purpose of this study was to examine the association between asthma and AF risk.

METHODS

We conducted a population-based nested case-control study including a total of 7439 newly-diagnosed adult patients with AF and 10,075 age-, gender-, comorbidity-, and cohort entry date-matched subjects without AF from the Taiwan National Health Insurance database. Exposure to asthma as well as medications including bronchodilators and corticosteroid before the index date was evaluated to investigate the association between AF and asthma as well as concurrent medications.

RESULTS

AF patients were 1.2 times (adjusted OR 1.2, 95% CI 1.109-1.298) more likely to be associated with a future occurrence of asthma independent of comorbidities and treatment with corticosteroids and bronchodilator. In addition, the risks of new-onset AF were significantly higher among current users of inhaled corticosteroid, oral corticosteroids, and bronchodilators. Newly users (within 6 months) have the highest risk (inhaled corticosteroid: OR, 2.13; 95% CI, 1.226-3.701, P=0.007; oral corticosteroid: OR, 1.932; 95% CI, 1.66-2.25, P<0.001; non-steroid bronchodilator: OR, 2.849; 95% CI, 2.48-3.273, P<0.001). A graded association with AF risk was also observed among subjects treated with corticosteroid (inhaled and systemic administration) and bronchodilators. New users (within 6 months) of these medications had the highest risk of AF (ICS: OR, 2.13; 95% CI, 1.226-3.701, P=0.007; oral corticosteroid: OR, 1.932; 95% CI, 1.66-2.25, P<0.001; non-steroid bronchodilator: OR, 2.849; 95% CI, 2.48-3.273, P<0.001). A graded association with AF risk was also observed among subjects treated with ICS or bronchodilator.

CONCLUSIONS

Asthma was associated with an increased risk of developing future AF.

The effect of beclometasone dipropionate/formoterol extra-fine fixed combination on the peripheral airway inflammation in controlled asthma

BACKGROUND

Suppression of small airway inflammation may contribute to achieving asthma control. We aimed to evaluate the additional effect of beclometasone dipropionate/formoterol (BDP/F) hydrofluoroalkane (HFA) pressurized metered dose inhaler (pMDI) (BDP/F-HFA 100/6 μg pMDI) on airway inflammation and functional parameters in asthma cases, who were optimally controlled by maintenance therapy.

METHODS

Ninety-five controlled asthmatic patients were included. They were grouped as Group 1 [budesonide/formoterol 320/9 μg dry powder inhaler (DPI)] and Group 2 (fluticasone/salmeterol 500/50 μg DPI) according to the combination they used. Then Group 3 was established by random selection from these two groups, and BDP/F-HFA 100/6 μg pMDI treatment was prescribed. All patients were evaluated in the beginning of the study and were re-evaluated at the end of a 3-week treatment period by spirometry, exhaled nitric oxide (eNO) levels, and small airway functional indices, namely, Sacin and Scond values.

RESULTS

There was no significant statistical difference in terms of age, height, weight, disease duration, symptoms, and spirometric parameters between the groups. There was a significant decrease in eNO levels in asthma cases who were on BDP/F-HFA therapy (p=0.001). A significant improvement in Sacin values at the end of the treatment period was observed in cases treated with BDP/F-HFA (p=0.001), indicating that inflammation was suppressed in peripheral airways.

CONCLUSIONS

These results emphasize that asthma treatment has mainly focused on the strategy to keep the disease under control; maintaining optimal functional level might be underestimated. BDP/F-HFA may have an additional favorable effect on the peripheral airway inflammation in the controlled asthma.

Small airways dysfunction in asthma: evaluation and management to improve asthma control

The small airways have been neglected for many years, but interest in the topic has been rekindled with recent advances in measurement techniques to assess this region and also the ability to deliver therapeutics to the distal airways. Current levels of disease control in asthmatic patients remain poor and there are several contributory factors including; poor treatment compliance, heterogeneity of asthma phenotypes and associated comorbidities. However, the proposition that we may not be targeting all the inflammation that is present throughout the whole respiratory tree may also be an important factor. Indeed decades ago, pathologists and physiologists clearly identified the importance of small airways dysfunction in asthmatic patients. With improved inhaler technology to deliver drug to target the whole respiratory tree and more sensitive measures to assess the distal airways, we should certainly give greater consideration to treating the small airway region when seeing our asthmatic patients in clinic. The aim of this review is to address the relevance of small airways dysfunction in the daily clinical management of patients with asthma. In particular the role of small particle aerosols in the management of patients with asthma will be explored.