Predicting Lung Deposition of Extrafine Inhaled Corticosteroid-Containing Fixed Combinations in Patients with Chronic Obstructive Pulmonary Disease Using Functional Respiratory Imaging: An In Silico Study

Aerosol Plumes of Inhalers Used in COPD

INTRODUCTION

The selection of inhaler device is of critical importance in chronic obstructive pulmonary disease (COPD) as the interaction between a patient's inhalation profile and the aerosol characteristics of an inhaler can affect drug delivery and lung deposition. This study assessed the in vitro aerosol characteristics of inhaler devices approved for the treatment of COPD, including a soft mist inhaler (SMI), pressurized metered-dose inhalers (pMDIs), and dry powder inhalers (DPIs).

METHODS

High-speed video recording was used to visualize and measure aerosol velocity and spray duration for nine different inhalers (one SMI, three pMDIs, and five DPIs), each containing dual or triple fixed-dose combinations of long-acting muscarinic receptor antagonists and long-acting β2-agonists, with or without an inhaled corticosteroid. Measurements were taken in triplicate at experimental flow rates of 30, 60, and 90 l/min. Optimal flow rates were defined based on pharmacopoeial testing requirements: 30 l/min for pMDIs and SMIs, and the rate achieving a 4-kPa pressure drop against internal inhaler resistance for DPIs. Comparison of aerosol plumes was based on the experimental flow rates closest to the optimal flow rates.

RESULTS

The Respimat SMI had the slowest plume velocity (0.99 m/s) and longest spray duration (1447 ms) compared with pMDIs (velocity: 3.65-5.09 m/s; duration: 227-270 ms) and DPIs (velocity: 1.43-4.60 m/s; duration: 60-757 ms). With increasing flow rates, SMI aerosol duration was unaffected, but velocity increased (maximum 2.63 m/s), pMDI aerosol velocity and duration were unaffected, and DPI aerosol velocity tended to increase, with a more variable impact on duration.

CONCLUSIONS

Aerosol characteristics (velocity and duration of aerosol plume) vary by inhaler type. Plume velocity was lower and spray duration longer for the SMI compared with pMDIs and DPIs. Increasing experimental flow rate was associated with faster plume velocity for DPIs and the SMI, with no or variable impact on plume duration, whereas pMDI aerosol velocity and duration were unaffected by increasing flow rate.

Modeled small airways lung deposition of two fixed-dose triple therapy combinations assessed with in silico functional respiratory imaging

BACKGROUND

Small airways disease plays a key role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and is a major cause of obstruction; therefore, it is a critical pharmacotherapy target. This study evaluated lung deposition of two inhaled corticosteroid (ICS)/long-acting β2-agonist/long-acting muscarinic antagonist single-inhaler triple therapies using in silico functional respiratory imaging (FRI). Deposition was assessed using real-world inhalation profiles simulating everyday use where optimal inhalation may be compromised.

METHODS

Three-dimensional airway models were produced from 20 patients with moderate-to-very severe COPD. Total, central, and regional small airways deposition as a percentage of delivered dose of budesonide/glycopyrronium/formoterol fumarate dihydrate (BGF) 160/7.2/5 µg per actuation and fluticasone furoate/umeclidinium/vilanterol (FF/UM/VI) 100/62.5/25 µg were evaluated using in silico FRI based on in vitro aerodynamic particle size distributions of each device. Simulations were performed using multiple inhalation profiles of varying durations and flow rates representing patterns suited for a pressurized metered-dose inhaler or dry-powder inhaler (four for BGF, two for FF/UM/VI, with one common profile). For the common profile, deposition for BGF versus FF/UM/VI was compared post-hoc using paired t-tests.

RESULTS

Across inhalation profiles, mean total lung deposition was consistently higher with BGF (47.0-54.1%) versus FF/UM/VI (20.8-22.7%) and for each treatment component, with greater deposition for BGF also seen in the central large airways. Mean regional small airways deposition was also greater across inhalation profiles with BGF (16.9-23.6%) versus FF/UM/VI (6.8-8.7%) and for each treatment component. For the common profile, total, central, and regional small airways deposition were significantly greater for BGF versus FF/UM/VI (nominal p < 0.001), overall and for treatment components; notably, regional small airways deposition of the ICS components was approximately five-fold greater with budesonide versus fluticasone furoate (16.1% vs. 3.3%).

CONCLUSIONS

BGF was associated with greater total, central, and small airways deposition for all components versus FF/UM/VI. Importantly, using an identical inhalation profile, there was an approximately five-fold difference in small airways deposition for the ICS components, with only a small percentage of the ICS from FF/UM/VI reaching the small airways. Further research is needed to understand if the enhanced delivery of BGF translates to clinical benefits.

Impulse Oscillometry, Small Airways Disease, and Extra-Fine Formulations in Asthma and Chronic Obstructive Pulmonary Disease: Windows for New Opportunities

In recent years, the perspective of management of respiratory disease has been gradually changing in light of the increasing evidence of small airways as the major site of airflow obstruction contributing to the development of both COPD and asthma already in early stages of disease. First and foremost, the evidence is redefining disease severity, identifying small airways disease phenotypes and early signs of disease, and revising prevalence and overall epidemiological data as well. Much effort has been put toward the instrumental assessment of small airways’ involvement and early detection. Several clinical trials have evaluated the advantage of extra-fine formulations which can best target the small airways in uncontrolled asthma and severe COPD. Here, we briefly present a practical overview of the role of the small airways in disease, the most appropriate diagnostic methods for quantifying their impairment, and provide some insight into the costs of respiratory management in Italy, especially in sub-optimally controlled disease.

Differential Performance and Lung Deposition of Levofloxacin with Different Nebulisers Used in Cystic Fibrosis

We compared the performance and levofloxacin (Quinsair) lung deposition of three nebulisers commonly used in CF (I-Neb Advance, eFlow rapid, and LC Plus) with the approved nebuliser Zirela. The delivered dose, delivery rate, and aerosol particle size distribution (APSD) for each device were determined using the methods described in the Pharmacopeia. High-resolution computed tomography scans obtained from seven adult patients with mild CF were used to generate computer-aided, three-dimensional models of their airway tree to assess lung deposition using functional respiratory imaging (FRI). The eFlow rapid and the LC Plus showed poor delivery efficiencies due to their high residual volumes. The I-Neb, which only delivers aerosols during the inspiratory phase, achieved the highest aerosol delivery efficiency. However, the I-Neb showed the largest particle size and lowest delivery rate (2.9 mg/min), which were respectively associated with a high extrathoracic deposition and extremely long nebulisation times (>20 min). Zirela showed the best performance considering delivery efficiency (159.6 mg out of a nominal dose of 240 mg), delivery rate (43.5 mg/min), and lung deposition (20% of the nominal dose), requiring less than 5 min to deliver a full dose of levofloxacin. The present study supports the use of drug-specific nebulisers and discourages the off-label use of general-purpose devices with the present levofloxacin formulation since subtherapeutic lung doses and long nebulisation times may compromise treatment efficacy and adherence.

Lung Deposition of Inhaled Extrafine Beclomethasone Dipropionate/Formoterol Fumarate/Glycopyrronium Bromide in Healthy Volunteers and Asthma: The STORM Study

Background:

An extrafine formulation triple therapy combination of beclomethasone dipropionate (BDP), formoterol fumarate (FF), and glycopyrronium bromide (GB) has been developed for the maintenance treatment of asthma and chronic obstructive pulmonary disease. This study used gamma scintigraphy to evaluate the intrapulmonary and extrapulmonary in vivo deposition of BDP/FF/GB, and the intrapulmonary regional distribution of the deposited formulation.

Methods:

This open-label uncontrolled nonrandomized single-dose study recruited 10 healthy volunteers and 9 patients with asthma. After a krypton-81m (^81mKr) ventilation scan was conducted, subjects inhaled study drug (four inhalations of BDP/FF/GB 100/6/12.5 μg radiolabeled using technetium-99 m [^99mTc]) through pressurized metered-dose inhaler, and a series of scintigraphic images were taken. The primary objective was to evaluate intrapulmonary drug deposition of BDP/FF/GB, determined as the percentage of nominal (i.e., metered) dose. Secondary endpoints included central/peripheral deposition ratio (C/P), and the standardized central/peripheral ratio (sC/P; ^99mTc aerosol C/P/^81mKr gas C/P).

Results:

All participants completed the study, with all scintigraphy procedures performed at one site. In patients with asthma, mean ± standard deviation intrapulmonary deposition was 25.50% ± 6.81%, not significantly different to that in healthy volunteers (22.74% ± 9.19%; p = 0.4715). Approximately half of the lung dose was deposited in the peripheral region of the lung (fraction deposited 0.52 ± 0.07 and 0.49 ± 0.06 in healthy volunteers and patients with asthma, respectively), resulting in C/P ratios of 0.94 ± 0.25 and 1.06 ± 0.25, respectively, with sC/P ratios of 1.80 ± 0.40 and 1.94 ± 0.38. Deposition patterns were similar in the two populations. BDP/FF/GB was well tolerated.

Conclusions:

This study confirmed that the extrafine particles delivered by BDP/FF/GB penetrate the peripheral areas of the lungs, with a similar proportion of particles deposited in the central and peripheral regions. Importantly, the deposition patterns were similar in healthy volunteers and patients with asthma, suggesting that disease characteristics are unlikely to impact drug deposition.

Clinical Trial Registration number: NCT03795350.

Interclass Difference in Pneumonia Risk in COPD Patients Initiating Fixed Dose Inhaled Treatment Containing Extrafine Particle Beclometasone versus Fine Particle Fluticasone

Background

Inhaled corticosteroids (ICS) afford therapeutic benefits in some COPD patients, but their widespread use is cautioned due to an increased risk of developing pneumonia. Subclass variations exist, and the risk profile differs for individual ICS. Formulation particle size has been identified as a potential effect modifier. The present study compared the risk of pneumonia among new COPD users of fixed-dose combination inhalers containing fine-particle fluticasone (fp-FDC-F) versus extrafine particle beclometasone (ef-FDC-BDP).

Methods

A propensity matched historical cohort study was conducted using data from the Optimum Patient Care Research Database. COPD patients aged ≥40 years with ≥1 year of continuous medical data who initiated fp-FDC-F or ef-FDC-BDP were compared. The primary outcome was time to pneumonia event, as treated, using either sensitive (physician diagnosed) or specific (physician diagnosed and x-ray or hospital admission confirmed) definitions.

Results

A total of 13,316 patients were matched. Initiation of fp-FDC-F (mean dosage furoate 99 µg; propionate 710 µg) was associated with an increased risk of pneumonia versus ef-FDC-BDP (mean beclometasone dose 395 µg), irrespective of definition (sensitive HR 1.38 95% CI 1.14–1.68; specific HR 1.31 95% CI 1.05–1.62).

Conclusion

In the current investigation, we found that in comparison to extrafine beclomethasone, commencing a formulation containing fluticasone is associated with an increased risk of developing pneumonia. These observations support the idea that not all ICS are equal in their adverse effects and subclass variations exist and should be carefully considered in the treatment choice.

Evaluation of small airway function and its application in patients with chronic obstructive pulmonary disease (Review)

Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammatory disease characterized by incomplete reversible airflow limitation. The diagnosis of COPD is mainly based on pulmonary function examination. In recent years, it has been indicated that small airway dysfunction occurs in patients with all stages of COPD, even in high-risk smoking groups who have not yet met the diagnostic criteria for COPD. Early recognition of small airway dysfunction and early initiation of small airway targeted therapy have become foci of research. In the present review, the methods of evaluating small airway function were summarized and their merits and shortcomings were discussed. Furthermore, the potential of targeted treatment of small airways in patients with COPD was outlined.

Long-acting muscarinic antagonists and small airways in asthma: Which link?

Involvement of small airways, those of <2 mm in internal diameter, is present in all stages of asthma and contributes substantially to its pathophysiologic expression. Therefore, small airways are a potential target to achieve optimal asthma control. Airway tone, which is increased in asthma, is mainly controlled by the vagus nerve that releases acetylcholine (ACh) and activates muscarinic ACh receptors (mAChRs) post-synaptically on airway smooth muscle (ASM). In small airways, M₃ mAChRs are expressed, but there is no vagal innervation. Non-neuronal ACh released from the epithelial cells that may express choline acetyltransferase in response to inflammatory stimuli, as well as from other structural cells in the airways, including fibroblasts and mast cells, can activate mAChRs. By antagonizing M₃ mAChR, the contraction of the ASM is prevented and, potentially, local inflammation can be reduced and the progression of remodeling may be averted. In fact, ACh also contributes to inflammation and remodeling of the airways and regulates the growth of ASM. Several experimental studies have demonstrated the potential benefit derived from the use of mAChR antagonists, mainly long-acting mAChR antagonists (LAMAs), on small airways in asthma. However, there are several confounding factors that may cause a wrong estimation of the relationship between LAMAs and small airways in asthma. Further studies are needed to differentiate broncholytic and anti-inflammatory effects of LAMAs and to better understand the interaction between LAMAs and corticosteroids, also in the context of a triple therapy that includes a β₂ -AR agonist, at different levels of the bronchial tree.