The inhalation characteristics of patients when they use different dry powder inhalers

Small Airways Disease Affects Aerosol Deposition in Children with Severe Asthma: A Functional Respiratory Imaging Study

Background: Small airways disease (SAD) in severe asthma (SA) is associated with high disease burden. Effective treatment of SAD could improve disease control. Reduced end-expiratory flows (forced expiratory flow [FEF]25-75 and FEF75) are considered sensitive indicators of SAD. Inhaled medication should be delivered to the smaller peripheral airways to treat SAD effectively. Aerosol deposition is affected by structural airway changes. Little is known about the effect of SAD on aerosol delivery to the smaller peripheral airways. Functional respiratory imaging (FRI) is a validated technique using 3D reconstructed chest computed tomography (CT) and computational fluid dynamics to predict aerosol deposition in the airways. Aim: This study aims to compare central and peripheral (= small airways) deposition between children with SA and SAD and children with SA without SAD, with different inhaler devices and inhalation profiles. Methods: FRI was used to predict the deposition of beclomethasone/formoterol dry powder inhaler (DPI), beclomethasone/formoterol pressurized metered dose inhaler with valved holding chamber (pMDI/VHC), and salbutamol pMDI/VHC for different device-specific inhalation profiles in chest-CT of 20 children with SA (10 with and 10 without SAD). SAD was defined as FEF25-75 and FEF75 z-score < -1.645 and forced vital capacity (FVC) z-score > -1.645. No SAD was defined as forced expiratory volume (FEV)1, FEF25-75, FEF75, and FVC z-score > -1.645. The intrathoracic, central, and peripheral airways depositions were determined. Primary outcome was difference in central-to-peripheral (C:P) deposition ratio between children with SAD and without SAD. Results: Central deposition was significantly higher (∼3.5%) and peripheral deposition was lower (2.9%) for all inhaler devices and inhalation profiles in children with SAD compared with children without SAD. As a result C:P ratios were significantly higher for all inhaler devices and inhalation profiles, except for beclomethasone administered through DPI (p = .073), in children with SAD compared with children without SAD. Conclusion: Children with SA and SAD have higher C:P ratios, that is, higher central and lower peripheral aerosol deposition, than children without SAD. The intrathoracic, central, and peripheral deposition of beclomethasone/formoterol using DPI was lower than using pMDI/VHC.

Uncovering patterns of inhaler technique and reliever use: the value of objective, personalized data from a digital inhaler

Electronic inhalers provide information about patterns of routine inhaler use. During a 12-week study, 360 asthma patients using albuterol Digihaler generated 53,083 inhaler events that were retrospectively analyzed. A total of 41,528 (78%) of the recorded inhalation events were suitable for flow analysis (having a PIF ≥ 18 L/min and <120 L/min). Median PIF, inhalation volume, inhalation duration, and time to PIF for these events steadily decreased between the first and last 10 days of the study, by 5.1%, 12.6%, 15.9%, and 6.4%, respectively. Continuous short-acting beta2-agonist (SABA) overuse, defined as ≥2 SABA inhalations/week throughout the study period, was seen in 29% (n = 104) of patients. Of 260 patients with ≥1 instance of acute short-term SABA overuse, 55 (21%) had a confirmed exacerbation. Electronic recording of real-life inhaler use can capture valuable, objective information that could inform disease management and clinical decision-making.

Lipid polymer hybrid nanoparticles against lung cancer and their application as inhalable formulation

Lung cancer is a leading cause of global cancer mortality, often treated with chemotherapeutic agents. However, conventional approaches such as oral or intravenous administration of drugs yield low bioavailability and adverse effects. Nanotechnology has unlocked new gateways for delivering medicine to their target sites. Lipid-polymer hybrid nanoparticles (LPHNPs) are one of the nano-scaled delivery platforms that have been studied to exploit advantages of liposomes and polymers, enhancing stability, drug loading, biocompatibility and controlled release. Pulmonary administration of drug-loaded LPHNPs enables direct lung deposition, rapid onset of action and heightened efficacy at low doses of drugs. In this manuscript, we will review the potential of LPHNPs in management of lung cancer through pulmonary administration.

Comparative study of the inhalation parameters of COPD patients through NEXThaler® and Ellipta® dry powder inhalers

The deposition of dry powder aerosol drugs depends on the inhalation parameters of the patients through the inhaler. These data are not directly measured in clinical practice. Their prediction based on the routinely measured spirometric data could help in choosing the appropriate device and optimizing the therapy. The aim of this study was to perform inhalation experiments to find correlations between inhalation parameters of COPD patients through two DPI devices and their native spirometric data, gender, age and disease severity. Another goal was to establish relationships between peak inspiratory flows through NEXThaler® and Ellipta® inhalers and their statistical determinants. Breathing parameters of 113 COPD patients were measured by normal spirometry and while inhaling through the two DPIs. Statistical analysis of the measured data was performed. The average values of peak inspiratory flow through the devices (PIFdev) were 68.4 L/min and 78.0 L/min for NEXThaler® and Ellipta®, respectively. PIFdev values were significantly higher for males than for females, but differences upon age, BMI and disease severity group were not significant. PIFdev values correlated best with their native spirometric counterparts (PIF) and linear relationships between them were revealed. Current results may be used in the future to predict the success of inhalation of COPD patients through DPI devices, which may help in the inhaler choice. By choosing the appropriate device-drug pair for each patient the lung dose can be increased and the efficiency of the therapy improved. Further results of the clinical study will be the subject of a next publication.

Towards More Precise Targeting of Inhaled Aerosols to Different Areas of the Respiratory System

Pharmaceutical aerosols play a key role in the treatment of lung disorders, but also systemic diseases, due to their ability to target specific areas of the respiratory system (RS). This article focuses on identifying and clarifying the influence of various factors involved in the generation of aerosol micro- and nanoparticles on their regional distribution and deposition in the RS. Attention is given to the importance of process parameters during the aerosolization of liquids or powders and the role of aerosol flow dynamics in the RS. The interaction of deposited particles with the fluid environment of the lung is also pointed out as an important step in the mass transfer of the drug to the RS surface. The analysis presented highlights the technical aspects of preparing the precursors to ensure that the properties of the aerosol are suitable for a given therapeutic target. Through an analysis of existing technical limitations, selected strategies aimed at enhancing the effectiveness of targeted aerosol delivery to the RS have been identified and presented. These strategies also include the use of smart inhaling devices and systems with built-in AI algorithms.

Dry Powder Inhalers: From Bench to Bedside

Dry powder inhalers (DPIs) are now widely prescribed and preferred by the majority of patients. These devices have many advantages over the traditional pressurized metered-dose inhaler (pMDI) but they do have disadvantages. The characteristics of the dose emitted from a DPI are affected by the inhalation manoeuvre used by a patient. Each patient is different and the severity of their lung disease varies from mild to very severe. This affects how they use an inhaler and so determines the type of dose they inhale. An understanding of the pharmaceutical science related to DPIs is important to appreciate the relevance of how patients inhale through these devices. Also, each type of DPI has its unique dose preparation routine, and thus it is essential to follow these recommended steps because errors at this stage may result in no dose being inhaled. All issues related to the inhalation manoeuvre and dose preparation are addressed in this chapter. The importance of the inhalation technique is highlighted with a realization of inhale technique training and checking. During routine patient management, devices should not be switched nor doses increased unless the patient has demonstrated that they can and do use their DPI.

Dry Powder Inhalation for Lung Delivery in Cystic Fibrosis

Pulmonary drug delivery has long been used for local and systemic administration of different medications used in acute and chronic respiratory diseases. Certain lung diseases, such as cystic fibrosis, rely heavily on chronic treatments, including targeted lung delivery. Pulmonary drug delivery possesses various physiological advantages compared to other delivery methods and is also convenient for the patient to use. However, the formulation of dry powder for pulmonary delivery proves challenging due to aerodynamic restrictions and the lower tolerance of the lung. The aim of this review is to provide an overview of the respiratory tract structure in patients with cystic fibrosis, including during acute and chronic lung infections and exacerbations. Furthermore, this review discusses the advantages of targeted lung delivery, including the physicochemical properties of dry powder and factors affecting clinical efficacy. Current inhalable drug treatments and drugs currently under development will also be discussed.

High inhaler resistance does not limit successful inspiratory maneuver among patients with asthma or COPD

INTRODUCTION

There has been an active discussion on the sustainability of inhaler therapy in respiratory diseases, and it has cast a shadow on pMDIs which rely on propellant with high global warming potential (GWP). DPIs offer a lower GWP and effective alternative, but there has been concern whether all patients can generate sufficient inspiratory effort to disperse the drug. This review focuses on airflow resistance of DPIs and its clinical relevance.

AREAS COVERED

For this narrative review, we searched the literature for studies comparing flow patterns with different devices. We also included a section on clinical trials comparing reliever administration with DPI, pMDI with spacer, and nebulizer during exacerbation.

EXPERT OPINION

The evidence supports the efficacy of DPIs irrespective of respiratory condition or age of the patient even during acute exacerbations. Air flow resistance does not limit the use of DPIs and the patients were able to generate sufficient inspiratory flow rate with almost any device studied. None of 16 identified clinical trials comparing reliever administration via DPIs to other types of devices during exacerbation or bronchial challenge showed statistically significant difference between the device types in FEV1 recovery. DPIs performed as well as other types of inhaler devices even during asthma or COPD exacerbation.

A review of upper airway physiology relevant to the delivery and deposition of inhalation aerosols

Developing effective oral inhaled drug delivery treatment strategies for respiratory diseases necessitates a thorough knowledge of the respiratory system physiology, such as the differences in the airway channel's structure and geometry in health and diseases, their surface properties, and mechanisms that maintain their patency. While respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma and their implications on the lower airways have been the core focus of most of the current research, the role of the upper airway in these diseases is less known, especially in the context of inhaled drug delivery. This is despite the fact that the upper airway is the passageway for inhaled drugs to be delivered to the lower airways, and their replicas are indispensable in current standards, such as the cascade impactor experiments for testing inhaled drug delivery technology. This review provides an overview of upper airway collapsibility and their mechanical properties, the effects of age and gender on upper airway geometry, and surface properties. The review also discusses how COPD and asthma affect the upper airway and the typical inhalation flow characteristics exhibited by the patients with these diseases.

Advancements in the Design and Development of Dry Powder Inhalers and Potential Implications for Generic Development

Dry powder inhalers (DPIs) are drug-device combination products where the complexity of the formulation, its interaction with the device, and input from users play important roles in the drug delivery. As the landscape of DPI products advances with new powder formulations and novel device designs, understanding how these advancements impact performance can aid in developing generics that are therapeutically equivalent to the reference listed drug (RLD) products. This review details the current understanding of the formulation and device related principles driving DPI performance, past and present research efforts to characterize these performance factors, and the implications that advances in formulation and device design may present for evaluating bioequivalence (BE) for generic development.

Investigating the Accuracy of the Digihaler, a New Electronic Multidose Dry-Powder Inhaler, in Measuring Inhalation Parameters

Background: The Digihaler^® is a Food and Drug Administration-approved, digital multidose dry powder inhaler with an integrated electronic module that provides patients and health care professionals with feedback on inhalation parameters, including usage, adherence, and technique. This study compared inhalation parameters measured using the Digihaler with readings made simultaneously using an inhalation profile recorder (IPR). Methods: This single-visit, open-label study enrolled children (4-17 years) and adults (18-55 years) with asthma, and adults (≥55 years) with chronic obstructive pulmonary disease (COPD). Participants made three separate inhalations using an empty Digihaler device, each measured simultaneously by the Digihaler and IPR. Inhalation profiles were downloaded from the devices at the end of the study. Inhalation parameters measured included peak inspiratory flow (PIF) and inhaled volume (inhV). The profile with the highest PIF and corresponding IPR profile were analyzed. Results: Overall, 150 participants were enrolled; inhalation data were available for 148 (50 children and 49 adults with asthma, and 49 with COPD). Mean (standard deviation [SD]) age was 39.1 (24.5) years; 51% of participants were male. Overall mean (SD) PIFs as measured by the Digihaler and IPR were 70.62 (17.73) L/min and 72.55 (19.42) L/min, respectively, with a mean percentage difference of -1.75% (95% confidence interval [CI]: -3.64 to 0.15). Mean percentage differences between the Digihaler and IPR measurements of PIF ranged from -2.97% among adults with COPD to 0.16% among children with asthma. Overall mean (SD) inhV for the Digihaler and IPR were 1.57 (0.69) L and 1.67 (0.73) L, respectively, with a mean percentage difference of -6.11 (95% CI: -8.08 to -4.13). There was a strong correlation between PIF and inhV measurements taken by the Digihaler and those taken by the IPR (Spearman's correlation coefficient = 0.96). Conclusions: Our findings confirm the ability of the Digihaler to provide accurate measurement of inhalation parameters when used by patients.

State of the Art in Capsule-Based Dry Powder Inhalers: Deagglomeration Techniques and the Consequences for Formulation Aerosolization

Commercially available dry powder inhalers (DPIs) are usually devices in a fixed combination with the intended formulation, and a change in medication by the physician often forces the patient to use a different device, requiring the patient to relearn how to use it, resulting in lower adherence and inadequate therapy. To investigate whether DPIs can achieve successful outcomes regardless of the formulation and flow rate used, a novel DPI and two commercially available devices were compared in vitro for their deagglomeration behavior for different binary blends and a spray-dried particle formulation. The results demonstrate that the novel device achieved the highest fine particle fraction (FPF) regardless of the formulations tested. In the binary mixtures tested, the highest emitted fraction was obtained by shaking out the powder due to the oscillating motion of the capsule in the novel device during actuation. For DPIs with high intrinsic resistance to airflow, similar FPFs were obtained with the respective DPI and formulation, regardless of the applied flow rate. Additionally, the development and use of binary blends of spray-dried APIs and carrier particles may result in high FPF and overcome disadvantages of spray-dried particles, such as high powder retention in the capsule.

Lung Function Can Predict the Expected Inspiratory Airflow Rate through Dry Powder Inhalers in Asthmatic Adolescents

Several factors affect drug delivery from dry powder inhalers (DPIs). Some are related to patient’s physiological characteristics, while others depend on DPIs’ technical aspects. The patient’s inspiratory airflow rate (IAR) affects the pressure drop and the turbulence needed to disaggregate the powder inside a DPI. The present study investigated whether lung function limitations occurring in asthmatic adolescents affect their IAR when inhaling through a DPI simulator. Eighteen consecutive adolescents with asthma were recruited, and IAR was randomly assessed at low-, mid-, and high-resistance regimens. A multiple logistic model was developed to evaluate the association of patients’ lung function characteristics and devices’ resistance with the probability to achieve the expected IAR (E-IAR). The mean value of E-IAR achieved seemed to be sex- and age-independent. Low- and high-resistance regimens were less likely to consent the E-IAR level (odds ratio [OR] = 0.035 and OR = 0.004, respectively). Only the basal residual volume and the inspiratory resistance, but not the Forced Expiratory Volume in 1 s (FEV1), seemed to affect the extent of IAR in asthmatic adolescents (OR = 1.131 and OR = 0.290, respectively). The results suggest that the assessment of current lung function is crucial for choosing the proper DPI for asthmatic adolescents.

From laminar to turbulent flow in a dry powder inhaler: The effect of simple design modifications

In order to better understand powder dispersion in dry powder inhaler (DPI) devices, a new powder disperser was designed, which uses flow modifiers to alter powder fluidization behavior so as to physically replicate various flow conditions observed in a range of commercial DPIs. The influence of these modifiers on the performance of the DPI was analyzed for flowrates progressing from laminar (15 L/min) to transitional (30 L/min), and finally turbulent flow regimes (60 L/min) in the device. The aerosol performance of the disperser was measured using a Next Generation Impactor. For flowrate in the laminar regime, powder evacuation from the disperser was generally insufficient (<30%), which was increased to >85% when the device was operated in the turbulent flow regime. In contrast, the highest fine particle fraction (FPF) and lowest throat deposition were achieved when operating in the transitional flow regime. The FPF could be increased further by applying flow modifications such as narrowing the air passage before the powder pocket, inducing localized turbulence (by a grid) near the powder pocket, and by changing the loading position of the powder. Flow modifiers had the most noticeable effect under a laminar flow regime, however, the device operated most efficiently under a transitional flow regime.

Measuring Peak Inspiratory Flow in Patients with Chronic Obstructive Pulmonary Disease

Dry powder inhalers (DPIs) are breath actuated, and patients using DPIs need to generate an optimal inspiratory flow during the inhalation maneuver for effective drug delivery to the lungs. However, practical and standardized recommendations for measuring peak inspiratory flow (PIF)—a potential indicator for effective DPI use in chronic obstructive pulmonary disease (COPD)—are lacking. To evaluate recommended PIF assessment approaches, we reviewed the Instructions for Use of the In-Check™ DIAL and the prescribing information for eight DPIs approved for use in the treatment of COPD in the United States. To evaluate applied PIF assessment approaches, we conducted a PubMed search from inception to August 31, 2021, for reports of clinical and real-life studies where PIF was measured using the In-Check™ DIAL or through a DPI in patients with COPD. Evaluation of collective sources, including 47 applicable studies, showed that instructions related to the positioning of the patient with their DPI, instructions for exhalation before the inhalation maneuver, the inhalation maneuver itself, and post-inhalation breath-hold times varied, and in many instances, appeared vague and/or incomplete. We observed considerable variation in how PIF was measured in clinical and real-life studies, underscoring the need for a standardized method of PIF measurement. Standardization of technique will facilitate comparisons among studies. Based on these findings and our clinical and research experience, we propose specific recommendations for PIF measurement to standardize the process and better ensure accurate and reliable PIF values in clinical trials and in daily clinical practice.

Carrier particle emission and dispersion in transient CFD-DEM simulations of a capsule-based DPI

The dispersion of carrier-based formulations in capsule-based dry powder inhalers depends on several factors, including the patient's inhalation profile and the motion of capsule within the device. In the present study, coupled computational fluid dynamics and discrete element method simulations of a polydisperse cohesive lactose carrier in an Aerolizer® inhaler were conducted at a constant flow rate of 100 L/min and considering an inhalation profile of asthmatic children between 5 and 17 years approximated from literature data. In relevant high-speed photography experiments, it was observed that the powder was distributed to both capsule ends before being ejected from the capsule. Several methods of ensuring similar behavior in the simulations were presented. Both the constant flow rate simulation and the profile simulations showed a high powder retention in the capsule (7.37-19.00%). Although the inhaler retention was negligible in the constant flow rate simulation due to consistently high air velocities in the device, it reached values of around 7% in most of the profile simulations. In all simulations, some of the carrier powder was ejected from the capsule as particle clusters. These clusters were larger in the profile simulation than in the constant flow rate simulation. Of the powder discharged from the capsule, a high percentage was bound in clusters in the profile simulation in the beginning and at the end of the inhalation profile while no more than 10% of the powder ejected from the capsule in the 100 L/min constant flow rate simulation were in clusters at any time. The powder emission from the capsule was studied, indicating a strong dependency of the powder mass flow from the capsule on the angular capsule position. When the capsule holes face the inhaler's air inlets, the air flow into the capsule restricts the powder discharge. The presented results provide a detailed view of some aspects of the powder flow and dispersion of a cohesive carrier in a capsule-based inhaler device. Furthermore, the importance of considering inhalation profiles in addition to conventional constant flow rate simulations was confirmed.

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.

Switching to the Dry-Powder Inhaler Easyhaler®: A Narrative Review of the Evidence

Asthma and chronic obstructive pulmonary disease (COPD) are major causes of morbidity and mortality worldwide. Optimal control of these conditions is a constant challenge for both physicians and patients. Poor inhaler practice is widespread and is a substantial contributing factor to the suboptimal clinical control of both conditions. The practicality, dependability, and acceptability of different inhalers influence the overall effectiveness and success of inhalation therapy. In this paper, experts from various European countries (Finland, Germany, Hungary, Italy, Poland, Spain, and Sweden) address inhaler selection with special focus on the Easyhaler^® device, a high- or medium–high resistance dry-powder inhaler (DPI). The evidence examined indicates that use of the Easyhaler is associated with effective control of asthma or COPD, as shown by the generally accepted indicators of treatment success. Moreover, the Easyhaler is widely accepted by patients, is reported to be easy to learn and teach, and is associated with patient adherence. These advantages help patient education regarding correct inhaler use and the rational selection of drugs and devices. We conclude that switching inhaler device to the Easyhaler may improve asthma and COPD control without causing any additional risks. In an era of climate change, switching from pressurized metered-dose inhalers to DPIs is also a cost-effective way to reduce emissions of greenhouse gases.

Optimizing Spray-Dried Porous Particles for High Dose Delivery with a Portable Dry Powder Inhaler

This manuscript critically reviews the design and delivery of spray-dried particles for the achievement of high total lung doses (TLD) with a portable dry powder inhaler. We introduce a new metric termed the product density, which is simply the TLD of a drug divided by the volume of the receptacle it is contained within. The product density is given by the product of three terms: the packing density (the mass of powder divided by the volume of the receptacle), the drug loading (the mass of drug divided by the mass of powder), and the aerosol performance (the TLD divided by the mass of drug). This manuscript discusses strategies for maximizing each of these terms. Spray drying at low drying rates with small amounts of a shell-forming excipient (low Peclet number) leads to the formation of higher density particles with high packing densities. This enables ultrahigh TLD (>100 mg of drug) to be achieved from a single receptacle. The emptying of powder from capsules is directly proportional to the mass of powder in the receptacle, requiring an inhaled volume of about 1 L for fill masses between 40 and 50 mg and up to 3.2 L for a fill mass of 150 mg.

Modeling of Inhalation Profiles Through Dry Powder Inhaler in Healthy Adults and Asthma Patients As a Prerequisite for Further In Vitro and In Silico Studies

Background: The severity of airway obstruction may affect patient's ability to perform an effective drug inhalation from a dry powder inhaler (DPI). Also, an incorrect inhalation technique may negatively affect the efficacy of asthma treatment. The aims of the study were (1) to analyze and compare inhalation profiles recorded with the use of different inhalation techniques, and thus, (2) to establish model inhalation profiles representative for healthy subjects and subjects with mild and moderate-to-severe asthma. Methods: This study was performed in healthy volunteers, patients with mild and moderate-to-severe asthma. A modified flow-volume test to define two different expiratory levels (to residual volume and half-way to residual volume) was performed. Inspiratory flow parameters were extracted: peak inspiratory flow rate (PIF_inh), time at which peak inspiratory flow rate occurs (tPIF_inh), total inhalation time (T), and inhaled volume (V). Test of frequency for tPIF_inh100% and tPIF_inh50% by asthma severity was performed, to provide information about initial flow accelerations. The impact of two different expiratory levels preceding inhalation (with severity of asthma as a categorical factor) on inspiratory flow parameters was examined. Results: PIF_inh was dependent upon asthma severity (p = 0.046). Type of exhalation before inhalation had no effect on PIF_inh values. V value was significantly affected both by asthma severity (p = 0.024) and type of exhalation before inhalation (p < 0.0001). Mean T value was influenced by type of exhalation before inhalation (p = 0.0003), but not by asthma severity. Mean tPIF_inh value was affected by the type of exhalation before inhalation only in healthy subjects (p = 0.01). Conclusions: Both asthma severity and type of exhalation before inhalation have little impact on the dynamics of inhalation through a DPI. An alternative form of equation describing inhalation profiles demonstrating a relationship between lung mechanics and dynamics of inspiratory profile has been proposed.

Inhaler technique in asthma and COPD: challenges and unmet knowledge that can contribute to suboptimal use in real life

Introduction: Inhalers are the most commonly used devices for lung drug delivery in asthma and COPD. Inhaler use offers several advantages but requires the user's proper mastery. The issue of inhaler technique is very important as inhaler misuse remains common in real life regardless of the inhaler used and is associated with poor disease control.Areas covered:This narrative review analyses the key-steps of inhaler mastery and the significance of the errors of use for the main devices. There are uncertainties on many tasks of inhaler use and on those variations from recommended steps that are considered as critical errors.Expert opinion: Despite technological advancements, an easy-to-use device is not yet available. Whatever the chosen inhaler, health care givers' proper practical education with the opportunity of feedback learning has a key-role for improving inhaler technique, but is time-consuming, and remains limited to few successful experiences. Newer digital technologies will be applied to the field of inhaler education, but the lack of knowledge on many practical aspects of inhaler technique might be a limit for its extensive implementation. Possibly digital innovation might substantially contribute to reduce inhaler misuse only if clinicians, manufacturers, and subjects will cooperate together on this issue.

Prevalence and Associated Factors of Suboptimal Daily Peak Inspiratory Flow and Technique Misuse of Dry Powder Inhalers in Outpatients with Stable Chronic Airway Diseases

Purpose

The present study aimed to investigate the prevalence and associated factors of suboptimal daily peak inspiratory flow (PIF) and technical misuse of three commonly used dry powder inhalers (DPIs) in outpatients with stable chronic airway diseases.

Patients and Methods

Included in this study were 85 outpatients with stable asthma, chronic obstructive pulmonary disease (COPD), or asthma-COPD Overlap (ACO) and had previously used any of Turbuhaler^® (TUR), Diskus^® (DIS), HandiHaler^® (HAN) between December 2018 and September 2019. The patient’s daily PIF against the resistance of a specific DPI and operation technique was investigated by two pharmacists by using In-Check DIAL G16 and a checklist.

Results

Of the 85 patients, the proportion of patients with a suboptimal daily PIF and technical misuse was 38.8% and 65.9%, respectively. In logistic regression, we observed that the factors that increase the risk for suboptimal daily PIF were age (OR=1.06) and combination with respiratory diseases (OR = 6.59). The factor that decreases the risk for misuse was the higher education level (OR =0.63).

Conclusion

Even if patients have received training at the time of initial prescription, the standardization of the use of DPIs by patients in our center was still unoptimistic. Age and combined with respiratory diseases were associated with suboptimal PIF. Higher education level decreased the incidence of technique misuse.

Inhalation Profiles Through a Dry Powder Inhaler: Relation Between Inhalation Technique and Spirometric Measures

Background: The understanding of the real flow profiles through a dry powder inhaler (DPI), generated by asthma patients, is a prerequisite for satisfactory drug delivery to the lungs. The aims of the study were to assess the relationship between spirometric measures and inhalation profiles through a low-resistance DPI, and to compare parameters of those profiles between optimal and suboptimal inhalation technique type. Methods: Both healthy adult volunteers and patients with asthma were included in the study. Spirometry was conducted along with modified flow-volume test to detect expiratory levels (maximum "100%" exhalation to residual volume [RV] and halfway "50%" to RV). These were the reference levels of the depth of exhalation for each patient to simulate the effect of incomplete exhalation. Individual inhalation profiles were recorded using spirometry in-house software as the volumetric airflow through the inhaler versus time. Inspiratory flow parameters were extracted: time to peak inspiratory flow through inhaler (PIF_inh), time at which peak inspiratory flow occurs (tPIF_inh), total inhalation time (T), and inhaled volume during maneuver (V). Results and Conclusions: There are significant relationships between spirometric indices and parameters of inhalation through a low-resistance, cyclohaler-type DPI (assessed by single-factor analysis of Spearman's rank correlation coefficient). Multiple regression models were constructed, predicting inspiratory flow parameters (including spirometric indices, demographic parameters, and inhaler's usage history as determinants). The exhalation halfway to RV before inhalation did not affect significantly PIF_inh and tPIF_inh (and, thus, initial flow dynamics) in asthma patients. T and V parameters were then significantly decreased, but seemed sufficient for successful DPI performance. Both exhalation to RV and incomplete exhalation halfway to RV preceding inhalation allow for effective usage of low-resistance DPI.

The contribution of patients' lung function to the inspiratory airflow rate achievable through a DPIs' simulator reproducing different intrinsic resistance rates

Background

The performance of DPIs depends on several physiological (patient-dependent) and technological (device-dependent) factors. The inspiratory airflow rate is the only active force generated and operating in the system for inducing the required pressure drop and eliciting the resistance-induced turbulence needed to disaggregate the powder through the device. The present study aimed to investigate in the most prevalent respiratory disorders whether and at what extent the inspiratory airflow rate achievable when inhaling through a DPIs’ simulator reproducing different intrinsic resistance regimens (low, mid, and high resistance) is affected by peculiar changes in lung function and/or can be predicted by any specific lung function parameter.

Methods

The inspiratory airflow rate was assessed in randomized order by the In-Check DIAL G16 at low, mid, and high resistance regimens in a sample of consecutive subjects at recruitment. Independent predictors of the probability to achieve the expected inhalation airflow rate were investigated by means of a multivariate logistic regression model, specific to the disease.

Results

A total of 114 subjects were recruited (asthmatics n=30; COPD n=50, restrictive patients n=16, and normal subjects n=18). The mean values of the expected inspiratory airflow rate achieved proved significantly different within the groups (p<0.0001), independently of sex and age. In asthmatics and in COPD patients, the mid-resistance regimen proved highly associated with the highest mean values of airflow rates obtained. Low- and high-resistance regimens were significantly less likely to consent to achieve the expected level of inspiratory airflow rate (OR<1 in all comparisons). Restrictive patients performed the lowest airflow rates at the low-resistance regimen (p<0.01). Unlike FEV¹, RV in asthmatics (OR=1.008); RV and I_Raw in COPD (OR=0.587 and OR=0.901, respectively), and FIF and TLC in restrictive patients (OR=1.041, and OR=0.962, respectively) proved the only sensitive predictors of the inspiratory airflow rate achievable at the different resistive regimens.

Conclusions

The intrinsic resistive regimen of DPIs can play a critical role. The patients’ lung function profile also affects the extent of their inhalation airflow rate. Some specific lung function parameters (such as: FIF; RV; I_Raw; TLC, but not FEV₁) may be regarded as specific predictors in real-life. In order to optimize the DPI choice, further to the device’s technology, also the current patients’ lung function should be properly investigated and carefully assessed.

A quantitative approach to predicting lung deposition profiles of pharmaceutical powder aerosols

Dry powder inhalers (DPI) are widely used systems for pulmonary delivery of therapeutics. The inhalation performance of DPIs is influenced by formulation features, inhaler device and inhalation pattern. The current review presents the affecting factors with great focus on powder characteristics which include particle size, shape, surface, density, hygroscopicity and crystallinity. The properties of a formulation are greatly influenced by a number of physicochemical factors of drug and added excipients. Since available particle engineering techniques result in particles with a set of modifications, it is difficult to distinguish the effect of an individual feature on powder deposition behavior. This necessitates developing a predictive model capable of describing all influential factors on dry powder inhaler delivery. Therefore, in the current study, a model was constructed to correlate the inhaler device properties, inhalation flow rate, particle characteristics and drug/excipient physicochemical properties with the resultant fine particle fraction. The r² value of established correlation was 0.74 indicating 86% variability in FPF values is explained by the model with the mean absolute errors of 0.22 for the predicted values. The authors believe that this model is capable of predicting the lung deposition pattern of a formulation with an acceptable precision when the type of inhaler device, inhalation flow rate, physicochemical behavior of active and inactive ingredients and the particle characteristics of DPI formulations are considered.

In vitro and in vivo performance modelling and optimisation of different dry powder inhalers: A complementary study of neural networks, genetic algorithms and decision trees

INTRODUCTION

Aerosol delivery from DPIs could be affected by different factors. This study aimed to evaluate and predict the effects of different factors on drug delivery from DPIs.

METHODS

Modelling and optimisation for both in vitro and in vivo data of different DPIs (Diskus, Turbohaler and Aerolizer) were carried out using neural networks associated with genetic algorithms and the results are confirmed using a decision tree (DT) and random forest regressor (RFR). All variables (the type of DPI, inhalation flow, inhalation volume, number of inhalations and type of subject) were coded as numbers before using them in the modelling study.

RESULTS

The analysis of the in vitro model showed that Turbohaler had the highest emitted dose compared with the Diskus and the Aerolizer. Increasing flow resulted in a gradual increase in the emitted dose. Little differences between the inhalation volumes 2 and 4 litres were shown at fast inhalation flow, and interestingly two inhalations showed somewhat higher emitted doses than one-inhalation mode with Turbohaler and Diskus at slow inhalation flow. Regarding the in vivo model, the percent of drug delivered to the lung was highly increased with Turbohaler and Diskus in healthy subjects where continuous contour lines were observed. The Turbohaler showed increased lung bioavailability with the two-inhalation modes, the Diskus showed a nearly constant level at both one and two inhalations at slow inhalation. The Turbohaler and Aerolizer showed little increasing effect moving from one to two inhalations at slow inhalation.

CONCLUSIONS

Modelling of the input data showed a good differentiating and prediction power for both in vitro and in vivo models. The results of the modelling refer to the high efficacy of Diskus followed by Turbohaler for delivering aerosol. With two inhalations, the three DPIs showed an increase in the percent of drug excreted at slow inhalations.

Inspiratory flow profile and usability of the NEXThaler, a multidose dry powder inhaler, in asthma and COPD

Background

Inhaler selection is important when managing respiratory conditions; a patient’s inhalation technique should be appropriate for the selected device, and patients should ideally be able to use a device successfully regardless of disease severity. The NEXThaler is a multidose dry-powder inhaler with a breath-actuated mechanism (BAM) and dose counter that activates only following inhalation, so effectively an ‘inhalation counter’. We assessed inspiratory flow through the NEXThaler in two studies and examined whether inhalation triggered the BAM.

Methods

The two studies were open-label, single-arm, and single visit. One study recruited patients with asthma aged ≥ 18 years; the other recruited patients with chronic obstructive pulmonary disease (COPD) aged ≥ 40 years. All patients inhaled twice through a placebo NEXThaler. The inspiratory profile through the device was assessed for each inhalation using acoustic monitoring, with flow at and time to BAM firing, peak inspiratory flow (PIF), and total inhalation time assessed.

Results

A total of 40 patients were enrolled in the asthma study: 20 with controlled asthma and 20 with partly controlled/uncontrolled asthma. All patients were able to trigger the BAM, as evidenced by the inhalation counter activating on closing the device. Mean flow at BAM firing following first inhalation was 35.0 (range 16.3–52.3) L/min; mean PIF was 64.6 (35.0–123.9) L/min. A total of 72 patients were enrolled in the COPD study, with data analysed for 69 (mean forced expiratory volume in 1 s 48.7% predicted [17–92%]). As with the asthma study, all patients, regardless of airflow limitation, were able to trigger the BAM. Mean flow at BAM firing following first inhalation was 41.9 (26.6–57.1) L/min; mean PIF was 68.0 (31.5–125.4) L/min. Device usability was rated highly in both studies, with 5 min sufficient to train the patients, and a click heard shortly after inhalation in all cases (providing feedback on BAM firing).

Conclusions

Inhalation flows triggering the BAM in the NEXThaler were similar between patients with controlled and partly controlled/uncontrolled asthma, and were similar across COPD airflow limitation. All enrolled patients were able to activate the device.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01430-9.

Impact of human behavior on inspiratory flow profiles in patients with pulmonary arterial hypertension using AOS™ dry powder inhaler device

Relative to healthy subjects, patients with pulmonary arterial hypertension often present with decreased respiratory muscle strength, resulting in decreased maximum inspiratory pressure. Little is known about the impact of reduced respiratory muscle strength on the ability to achieve the peak inspiratory pressures needed for effective drug delivery when using portable dry powder inhalers (≥1.0 kPa). The objective of this study was to assess the impact of inhaler resistance and patient instruction on the inspiratory flow profiles of pulmonary arterial hypertension patients when using breath-actuated dry powder inhalers. The inspiratory flow profiles of 35 patients with pulmonary arterial hypertension were measured with variants of the RS01 dry powder inhaler. Profiles were determined with a custom inspiratory flow profile recorder. Results showed that going from the low resistance RS01 dry powder inhaler to the high resistance AOS® dry powder inhaler led to increases in mean peak inspiratory pressures for pulmonary arterial hypertension subjects from 3.7 kPa to 6.5 kPa. Instructions that ask pulmonary arterial hypertension subjects to inhale with maximal effort until their lungs are full led to a mean peak inspiratory pressures of 6.0 kPa versus 2.1 kPa when the same subjects are asked to inhale comfortably. Significant decreases in mean peak inspiratory pressures are also observed with decreases in lung function, with a mean peak inspiratory pressures of 7.2 kPa for subjects with FEV1 > 60% predicted, versus 3.3 kPa for those subjects with FEV1 < 50% predicted. In conclusion, despite having reduced respiratory muscle strength, subjects with pulmonary arterial hypertension can effectively use a breath-actuated dry powder inhaler. The probability of achieving effective dose delivery may be increased by using dry powder inhalers with increased device resistance, particularly when subjects do not follow the prescribed instructions and inhale comfortably.

In-vitro and particle image velocimetry studies of dry powder inhalers

Inhalation drug delivery has seen a swift rise in the use of dry powder inhalers (DPIs) to treat chronic respiratory conditions. However, universal adoption of DPIs has been restrained due to their low efficiencies and significant drug losses in the mouth-throat region. Aerosol efficiency of DPIs is closely related to the fluid-dynamics characteristics of the inhalation flow generated from the devices, which in turn are influenced by the device design. In-vitro and particle image velocimetry (PIV) have been used in this study to assess the aerosol performance of a model carrier formulation delivered by DPI devices and to investigate their flow characteristics. Four DPI device models, with modification to their tangential inlets and addition of a grid, have been explored. Similar aerosol performances were observed for all four device models, with FPF larger than 50%, indicating desirable lung deposition. A high swirling and recirculating jet-flow emerging from the mouthpiece of the DPI models without the grid was observed, which contributed to particle deposition in the throat. DPI models where the grid was present showed a straightened outflow without undesired lateral spreading, that reduced particle deposition in the throat and mass retention in the device. These findings demonstrate that PIV measurements strengthen in-vitro evaluation and can be jointly used to develop high-performance DPIs.

The value of “General Practitioners–Specialists” mode: A focus group study of patients with asthma in mastering inhalation skills

This study focused on using “General Practitioners–Specialists” (GP-S) mode to teach the patients with asthma to master inhalation skills. 200 patients with asthma being admitted to the respiratory department of Shanghai Changhai Hospital were included in the study from January to December in 2018. There were 100 cases in the control group and 100 cases in the experimental group. The control groups received routine instruction and the experimental group adopted GP-S mode education, respectively, to learn mastering dry powder inhaler skills. The level of mastery and errors in the use of inhaled medications were recorded after each guidance. After four times’ instruction in two different ways, the patient’s mastery of inhalation skills gradually improved. After the guidance through the GP-S mode, the incidence of inhalation errors after each times instruction was 67%, 28%, and 7%, respectively. The later one was significantly lower than the previous one (67% vs. 28%, χ2 = 30.496, p < 0.001; 28% vs. 7%, χ2 = 15.273, p < 0.001). After twice instructions, the GP-S mode was associated with the lower incidence of inhaler device operating errors versus the regular guidance method (10% vs. 26%, χ2 = 8.672, p = 0.005); the same as the third guidance (2% vs. 11%, χ2 = 6.664, p = 0.018). Similarly, after thrice instructions, the incidence of inhalation method errors in the GP-S mode group was significantly lower than the regular guidance mode group (4% vs. 15%, χ2 = 7.037, p = 0.018), and there was still existing statistical difference of inhalation method errors between the two groups after four times instructions (3% vs. 11%, χ2 = 4.916, p = 0.049). General Practitioners–Specialists mode can effectively improve the patient’s mastery of inhalation skills, which significantly reduced the incidence of errors in the use of inhaled drugs and improved the overall management effectivity of asthma and patients’ compliance.

Estimating inter-patient variability of dispersion in dry powder inhalers using CFD-DEM simulations

Drug delivery from a capsule-based dry powder inhaler depends on the inhaler's design, the drug's formulation, and the inhalation maneuver. The latter affects both the air flow and the capsule motion in the inhaler. It is well known that patient-to-patient variability is a major challenge in the design of new inhaler types. Modeling and simulation are important tools for understanding such systems, yet quite complex. Simulation studies of capsule-based dry powder inhalers have disregarded the transient nature of the inhalation process, adopting a constant flow rate through the inhaler instead. In addition, either no capsules, a capsule in a fixed position, or a capsule rotating at a constant rate have been considered. In this work, literature data for three inhalation flow profiles were incorporated into coupled simulations of the air flow and carrier particle motion through an Aerolizer® dry powder inhaler with a rotating capsule and compared to simulations at constant air flow rates. The results for the profile simulations indicated that the carrier powder experienced larger velocity fluctuations. Acceleration events were tracked as a measure of collision- and flow-induced dispersion. The majority of fast particle accelerations occurred when the particles collided with the swirl chamber walls. Of the two common particle dispersion metrics, only the peak particle force distribution appeared to be sensitive to the inhalation profiles, while the effect of the profiles on the cumulative impulse was small.

Patient Inspiratory Maneuver Performance; Peak Lungpower, Acceleration and Volume

Background: Use of drug delivery devices between nebulizers, dry powder inhalers (DPIs), or metered dose inhalers (MDIs), for treating patients with asthma and chronic obstructive pulmonary disease (COPD), is based on patients' capability of coordinating the inhalation maneuver and achieving sufficient airflow. There are limited data available with regard to how patients meet the requirements of successful inhalation performance, and how the concept of inspiratory lungpower could be applied. The aim of this work was to study the patient inspiratory airflow profile performance in large data sets. We analyzed how the Kamin-Haidl inhalation criteria were met by patients with DPIs such as Easyhaler for combination therapy (EH-combi), Easyhaler for monotherapy (EH-mono), Diskus, and Turbuhaler (TH), and applied peak lungpower instead of peak inspiratory flow rate as an indicator of patient performance. Materials and Methods: Data sets gathered in two previous studies for DPIs, that is, EH-combi, EH-mono, Diskus, and TH, were used to analyze how inspiratory lungpower representing inspiratory muscle power, flow acceleration, and volume after peak met the inhalation criteria. The measured patient airflow profiles through inhalers were assessed for patients with asthma or COPD. Results: Based on the Kamin-Haidl inhalation criteria, successful inhalation requirements were met with EH-combi in 96.1% and with EH-mono in 92.6% of patients. The success rates were 89.5% and 84.6% with Diskus and TH, respectively, (p < 0.0001 between devices). In patients with asthma or COPD, the mean lungpower was 7.51 and 6.15 W for EH-combi, 8.79 and 6.88 W for EH-mono, 7.18 and 4.36 W for Diskus, and 9.65 and 6.86 W for TH, respectively, when patients followed the manufacturer's written instructions. Conclusions: Lungpower applied to the Kamin-Haidl inhalation criteria concept could be an applicable method for reviewing patient performance for different DPIs despite DPIs' characteristic differences in airflow resistance. In light of these results, DPIs provide a feasible treatment option for a large majority of respiratory patients.

The dry powder inhaler features of the Easyhaler that benefit the management of patients

Introduction: Inhaled therapies are likely to continue to dominate asthma and chronic obstructive pulmonary disease treatment. Dry powder inhalers (DPIs) have several advantages over pressurized metered-dose inhaler (pMDIs), that are most frequently marketed world-wide, but often difficult to use. This literature search focus on DPI features, with respect to Easyhaler, that may affect their use and patients' clinical benefit.Areas covered: DPIs are breath-actuated, easy to use, convenient to use, and more environmentally friendly. During inhalation, the formulation in a DPI is disaggregated by a turbulent airflow energy to generate particles with the greatest likelihood of deposition into the airways. The resistance among DPIs varies from low to high and those with high resistance are wrongly considered as difficult to use. Multidose reservoir-type DPIs have been developed to efficiently deliver a wide range of medications, including the fixed-dose combination of budesonide and formoterol. Easyhaler® shares a similar shape with pMDIs and, as other DPIs, its performance is unaffected by environmental and storage conditions. Due to Easyhaler internal design, dose emission is consistent irrespective of the inhalation flow used by each patient.Expert opinion: Easyhaler® may be considered one of the most convenient inhalers, for daily use, in patients with asthma or COPD.

The Confusing World of Dry Powder Inhalers: It Is All About Inspiratory Pressures, Not Inspiratory Flow Rates

Dry powder inhalers (DPIs) all have the ability to aerosolize dry powders, but they each offer different operating mechanisms and resistances to inhaled airflow. This variety has resulted in both clinician and patient confusion concerning DPI performance, use, and effectiveness. Particularly, there is a growing misconception that a single peak inspiratory flow rate (PIFR) can determine a patient's ability to use a DPI effectively, regardless of its design or airflow resistance. For this review article, we have sifted through the relevant literature concerning DPIs, inspiratory pressures, and inspiratory flow rates to provide a comprehensive and concise discussion and recommendations for DPI use. We ultimately clarify that the controlling parameter for DPI performance is not the PIFR but the negative pressure generated by the patient's inspiratory effort. A pressure drop ∼≥1 kPa (∼10 cm H2O) with any DPI is a reasonable threshold above which a patient should receive an adequate lung dose. Overall, we explore the underlying factors controlling inspiratory pressures, flow rates and dispensing, and dispersion characteristics of the various DPIs to clarify that inspiratory pressures, not flow rates, limit and control a patient's ability to generate sufficient flow for effective DPI use.

The effect of inspiratory parameters after two separate inhalations on the dose emission of theophylline from low and high resistance dry powder inhalers

The dose emission from DPIs can be affected by the inspiratory parameters achieved by the patient as well as the device in-use. Conventional in-vitro dose emission methodology was used, but instead of using inhalation volume (Vin) of 2 or 4 L and peak inhalation flow (PIF) corresponding to 4 kPa, a range of PIFs (28.3, 60, 90 and 120 L min⁻¹) and Vins (0.5, 0.75, 1, 1.5, 2, and 4 L) were used. The formulation was composed of spray dried Theophylline as a model drug with Lactohale® α lactose monohydrate carrier. The formulation was aerosolised using two DPIs; a low resistance Breezhaler® and high resistance Handihaler®. The formulation showed a consistent dose content uniformity with a Coefficient of Variation (CV) of 1.70%. The drug distribution on the surface of the carrier was obvious from the SE micrographs with some drug particles lodged into lactose crevices. The dose emission after the first inhalation (ED1) and total emitted dose (TED) of theophylline increased with PIF and Vin, irrespective of the inhaler device. However, the dose delivered was superior for the Handihaler® compared to Breezhaler®. Drug retention in the capsule and device was high at low PIFs and Vins and reduced after the second inhalation. Therefore, our study supports the recommendations for patients who cannot achieve sufficient PIF and Vin to inhale twice for each dose to ensure the better clinical outcome.

Understanding Dry Powder Inhalers: Key Technical and Patient Preference Attributes

Inhalable medications for patients with asthma and chronic obstructive pulmonary disease (COPD) can be confusing even for health care professionals because of the multitude of available devices each with different operating principles. Dry powder inhalers (DPI) are a valuable option for almost all of the patients with asthma or COPD. Based on recorded patient inspiratory profiles, the peak inspiratory flow requirement of 30 L min⁻¹ of high-resistance devices does not usually pose any practical limitations for the patients. Suboptimal adherence and errors in device handling are common and require continuous checking and patient education in order to avoid these pitfalls of all inhalation therapy. The aim of this opinion paper is to describe the working principles of DPIs and to summarise their key properties in order to help prescribing the correct inhaler for each patient.

Funding: Orion Pharma.

Use of inspiratory profiles from patients with chronic obstructive pulmonary disease (COPD) to investigate drug delivery uniformity and aerodynamic dose emission of indacaterol from a capsule based dry powder inhaler

Most patients using dry powder inhalers (DPIs) are unable to achieve the inhalation parameters recommended for pharmacopoeial in-vitro dose emission testing. The dose emission characteristics of indacaterol Breezhaler (IB) have been measured using COPD patients' inhalation profiles (IPs) when using IB and replayed in-vitro using a breath simulator attached to an Andersen Cascade Impactor. The peak inhalation flow (PIF) of the profiles ranged from 28.3 to 87.8 L/min and inhaled volumes (Vin) from 0.7 to 3 L. The indacaterol total emitted doses (TED), fine particle dose (FPD) and mass median aerodynamic diameter (MMAD) were measured. TED varied between 61% to 83% of the 150 μg nominal dose, the FPD was found to vary between 19% and 30% and the MMAD from 3.7 μm to 2.3 μm with the increase of the profiles' PIF and Vin. The mean (SD) values were 113.4(8.9) μg, 39.7(5.0) μg and 2.7(0.5) μm, respectively. The quantity and the quality of the emitted dose from the indacaterol Breezhaler® are dependent on the capability of a patient generating an optimal inhalation profile. Therefore, when using the IB patients should be encouraged to inhale as fast as they can from the start of their inhalation and for as long as possible.

Easyhaler®: an overview of an inhaler device for day-to-day use in patients with asthma and chronic obstructive pulmonary disease

Inhalation therapy is likely to continue to dominate asthma and chronic obstructive pulmonary disease (COPD) treatment. The pressurised metered-dose inhaler (pMDI) accounts for most of the global inhaler market, but this kind of device is difficult to use properly. Dry powder inhalers (DPIs) have several advantages over pMDIs: they are breath-activated, easy and convenient to use, and environmentally friendly. The Easyhaler^® (Orion; Finland) is a multidose reservoir-type DPI developed to efficiently deliver a wide range of medications, including fixed-dose combinations of bronchodilators and corticosteroids. Easyhaler shares a similar shape with the pMDI, and its performance is unaffected by moisture, dropping, vibration, and freezing/thawing. For these reasons, Easyhaler may be considered one of the most convenient inhalers for daily use in patients with asthma or COPD.

Inhaler Devices for Delivery of LABA/LAMA Fixed-Dose Combinations in Patients with COPD

Inhaled fixed-dose combinations (FDCs) of a long-acting β-agonist (LABA) and a long-acting muscarinic antagonist (LAMA) have become the cornerstone for the maintenance treatment of symptomatic COPD patients. In this regard, global COPD treatment guidelines have recognized the importance of inhaler devices as integral contributors to the effectiveness of LABA/LAMA FDCs and recommend regular assessment of inhaler device use by the patients in order to improve long-term clinical outcomes. Optimal disease control is also highly dependent upon patient preferences and adherence to inhaler devices. This review objectively examines and compares the major inhaler devices used to deliver different LABA/LAMA FDCs, discusses the inhaler device characteristics that determine drug deposition in the airways, real-life preference for inhaler devices, and handling of inhaler devices that impact the results of the long-term management of COPD. The introduction of new LABA/LAMA FDCs, new inhaler devices, and more clinical studies have created confusion among physicians in choosing the optimal inhaled therapy for COPD patients; in this context, this review attempts to provide an evidence-based framework for informed decision-making with a particular focus on the inhaler devices.Funding. The preparation of this manuscript was funded by Novartis Pharma AG.

Inhaled salbutamol from aerolizer and diskus at different inhalation flows, inhalation volume and number of inhalations in both healthy subjects and COPD patients

The aim of the present study was to demonstrate the effect of inhalation-flow, inhalation-volume and number of inhalations on aerosol-delivery of inhaled-salbutamol from two different dry powder inhalers (DPIs) in both healthy-subjects and chronic obstructive pulmonary disease (COPD) patients. Relative pulmonary-bioavailability and systemic-bioavailability of inhaled-salbutamol, delivered by Diskus and Aerolizer, was determined in 24-COPD patients and 24-healthy subjects. The healthy-subjects and the COPD-patients participated in the study for 7 days in which they received 4 study doses of 200 μg salbutamol (one slow-inhalation, two slow-inhalations, one fast-inhalation, and two fast-inhalations) in four alternative days with 24 hr washout period after each dose. Two urine-samples were collected from each study subjects. The first was provided 30 min post inhalation (USAL0.5), as an index of relative pulmonary-bioavailability, and the second was pooled to 24 hr post inhalation (USAL24), as an index of systemic-bioavailability. Fast-inhalation resulted in significantly higher USAL0.5 and USAL24 than slow-inhalation (p˂0.05) after one-inhalation in both healthy-subjects and COPD-patients but there was no significant difference between slow and fast-inhalation after two-inhalations. One-inhalation resulted in significantly higher USAL0.5 and USAL24 in healthy-subjects compared to COPD-patient at both slow and fast-inhalation (p˂0.05) except USAL0.5 with Diskus at slow-inhalation there was no significant difference. Also, two-inhalations resulted in significantly higher USAL0.5 and USAL24 compared to one-inhalation at slow-inhalation only (p˂0.05). No significant difference was found between Aerolizer and Diskus except in USAL0.5 of one slow-inhalation in both health-subjects and COPD-patients (p = 0.048 and 0.047, respectively). Device-formula relation is present at low inhalation-flow since Diskus resulted in significantly higher USAL0.5 and USAL24 in healthy-subjects compared to COPD-patient at slow inhalation than Aerolizer. It is essential to inhale-twice and as hard and deep as possible from each dose when using DPI especially with COPD-patients having poor inspiratory efforts such as elderly patients and children.

Determination of Passive Dry Powder Inhaler Aerodynamic Particle Size Distribution by Multi-Stage Cascade Impactor: International Pharmaceutical Aerosol Consortium on Regulation & Science (IPAC-RS) Recommendations to Support Both Product Quality Control and Clinical Programs

The multi-stage cascade impactor (CI) is the mainstay method for the determination of the aerodynamic particle size distribution (APSD) of aerosols emitted from orally inhaled products (OIPs). CIs are designed to operate at a constant flow rate throughout the measurement process. However, it is necessary to mimic an inhalation maneuver to disperse the powder into an aerosol when testing passive dry powder inhalers (DPIs), which constitute a significant portion of available products in this inhaler class. Methods in the pharmacopeial compendia intended for product quality assurance initiate sampling by applying a vacuum to the measurement apparatus using a timer-operated solenoid valve located downstream of the CI, resulting in a period when the flow rate through the impactor rapidly increases from zero towards the target flow rate. This article provides recommendations for achieving consistent APSD measurements, including selection of the CI, pre-separator, and flow control equipment, as well as reviewing considerations that relate to the shape of the flow rate-sampling time profile. Evidence from comparisons of different DPIs delivering the same active pharmaceutical ingredients (APIs) is indicative that the compendial method for APSD measurement is insensitive as a predictor of pharmacokinetic outcomes. Although inappropriate for product quality testing, guidance is therefore provided towards adopting a more clinically realistic methodology, including the use of an anatomically appropriate inlet and mimicking patient inhalation at the DPI while operating the CI at constant flow rate. Many of these recommendations are applicable to the testing of other OIP classes.

What to consider before prescribing inhaled medications: a pragmatic approach for evaluating the current inhaler landscape

Inhaled therapies are the cornerstone of treatment in asthma and chronic obstructive pulmonary disease, and there are a multitude of devices available. There is, however, a distinct lack of evidence-based guidance for healthcare providers on how to choose an appropriate inhaler. This review aims to summarise recent updates on topics related to inhaler choice, and to offer practical considerations for healthcare providers regarding currently marketed devices. The importance of choosing the right inhaler for the right patient is discussed, and the relative merits of dry powder inhalers, pressurised metered dose inhalers, breath-actuated pressurised metered dose inhalers, spacers and soft mist inhalers are considered. Compiling the latest studies in the devices therapy area, this review focuses on the most common types of handling errors, as well as the comparative rates of incorrect inhalation technique between devices. The impact of device-specific handling errors on inhaler performance is also discussed, and the characteristics that can impair optimal drug delivery, such as inhalation flow rate, inhalation volume and particle size, are compared between devices. The impact of patient perceptions, behaviours and problems with inhalation technique is analysed, and the need for appropriate patient education is also highlighted. The continued development of technology in inhaler design and the need to standardise study assessment, endpoints and patient populations are identified as future research needs. The reviews of this paper are available via the supplemental material section.

In Vitro Flow Rate Dependency of Delivered Dose and Fine Particle Dose of Salmeterol/Fluticasone Propionate Easyhaler and Seretide Diskus with Patient Flow Rates Collected in a Randomized Controlled Trial

Background: The Easyhaler^® device-metered dry powder inhaler containing Salmeterol and Fluticasone propionate (S/F) has been developed for the treatment of patients with asthma and chronic obstructive pulmonary disease (COPD). We report two studies which evaluated the in vitro flow rate dependence of delivered dose (DD) and fine particle dose (FPD) of S/F Easyhaler versus Seretide Diskus^®.

Methods: A randomized controlled trial (RCT) assessed inspiratory flow parameters of S/F Easyhaler and Seretide Diskus in subgroups of patients with asthma (children, adolescents and adults, and elderly) and in COPD patients. The 10th, 50th, and 90th percentile airflow rates were determined and utilized in vitro, to evaluate flow rate dependence of DD and FPD. Flow rate dependence was evaluated relative to the result obtained at the 50th percentile and any values deviating from 100% indicated flow rate dependence. The volumetric flow rate dependence (Q) index derived from FPD at 10th and 90th percentile airflows was also evaluated.

Results: Overall, 227 patients were enrolled and randomized; 216 completed the RCT. In total, 55.5% of patients were female, and the mean age was 46.3 years. Clinically relevant airflow rates (46, 68, and 85 L/min for S/F Easyhaler and 44, 71, and 96 L/min for Seretide Diskus) were carried forward into the in vitro study, which demonstrated similar flow rate dependence of DD and FPD for S/F Easyhaler compared with Seretide Diskus; all values were within ±15% limits across the 10th, 50th, and 90th percentile airflow rates. Q index results suggested that both S/F Easyhaler and Seretide Diskus are medium airflow-dependent products.

Conclusions: Similar in vitro flow rate dependence of DD and FPD was demonstrated for S/F Easyhaler compared with Seretide Diskus, across a range of clinically relevant airflow rates, collected from patients with asthma and COPD.

Mishandling of pMDI and DPI inhalers in asthma and COPD - Repetitive and non-repetitive errors

BACKGROUND

Pharmacological treatment of asthma and chronic obstructive pulmonary disease (COPD) is based mainly on inhaled medications. There is a continuous need to examine and train patients in their inhalation technique. The objective of the presented study is to determine whether the errors which patients made during inhalations are repetitive, and therefore easier to eradicate, or rather accidental, hence require more attention and effort from the health care professionals.

METHODS

It was a prospective, cohort study which included adults with asthma or COPD, who have used at least one inhaler daily on a regular basis. Inhalation technique was evaluated twice in a six months interval basing on a list of the most common errors in the inhalation technique. There was no training of inhalation skills between visits.

RESULTS

There were 92 patients (46 asthmatics, 46 with COPD; median age 66 years, median duration of the disease 10 years) included into the analysis. 92% of patients made at least one error during their inhalation. Among pMDI users the most common device mishandlings were: no or too short breath-holding after inhalation (60% of the patients during the first visit; 50% during the 2nd), too rapid and too forceful inhalation (52%; 61%) and lack of exhalation before the use of the medicine (48%; 43%). Among the DPI users, the most numerous errors were: no or too short (less than 3 s) breath-holding after inhalation (62%; 55%) and slow and not forceful enough inhalation (38%; 36%). When comparing the mishandlings in the inhalation technique conducted during the first and second visit the majority of the errors conducted by the patients were repetitive. However, some errors such as too early termination of inhalation (p = 0.016), inhalation through the nose during actuation (p = 0.002) among pMDI users and lack of expiration before inhalation (p = 0.027) among DPI users, were non-permanent.

CONCLUSIONS

Improper inhalation technique is very common and the majority of errors made in inhalation technique are repetitive. This emphasizes the role of an ongoing verification and training of a proper inhalation technique in all patients that are regularly treated with inhalers.