On the use of dry powder inhalers in situations perceived as constrained

Clinical characteristics of chronic obstructive pulmonary disease patients with superoptimal peak inspiratory flow rate

Characteristics of chronic obstructive pulmonary disease (COPD) patients with superoptimal peak inspiratory flow rates (PIFR) has not been thoroughly investigated. This study aimed to compare the characteristics between COPD patients with superoptimal PIFR and those with optimal and sub-optimal PIFR. PIFR was measured using In-Check DIAL G16 and categorized into sub-optimal (PIFR lower than that required by the patient's device), optimal, and superoptimal (peak PIFR ≥ 90 L/min). Considering COPD patients with sub-optimal PIFR as the reference group, analyses were performed to identify PIFR-related factors. Subgroup analysis was performed according to the forced expiratory volume in 1 s (FEV1) % of the predicted value (%pred). Among 444 post-bronchodilator-confirmed COPD patients from seven tertiary hospitals in South Korea, 98, 223, and 123 were classified into the sub-optimal, optimal, and superoptimal PIFR groups, respectively. The superoptimal PIFR group were younger, had an increased proportion of males, a higher body mass index, lowest number of comorbidities and less frequent exacerbation in the previous year, as well as the highest forced vital capacity %pred. The adjusted odds ratio for frequent exacerbation in the previous year was lower in the superoptimal PIFR group than in the sub-optimal PIFR group and was more pronounced in patients with an FEV1%pred of < 70%. COPD patients with superoptimal PIFR have clinical characteristics different from those patients with the sub-optimal and optimal PIFR. Having a high inspiratory flow may be a favorable trait in COPD.

Aspherical, Nano-Structured Drug Delivery System with Tunable Release and Clearance for Pulmonary Applications

Addressing the challenge of efficient drug delivery to the lungs, a nano-structured, microparticulate carrier system with defined and customizable dimensions has been developed. Utilizing a template-assisted approach and capillary forces, particles were rapidly loaded and stabilized. The system employs a biocompatible alginate gel as a stabilizing matrix, facilitating the breakdown of the carrier in body fluids with the subsequent release of its nano-load, while also mitigating long-term accumulation in the lung. Different gel strengths and stabilizing steps were applied, allowing us to tune the release kinetics, as evaluated by a quantitative method based on a flow-imaging system. The micro-cylinders demonstrated superior aerodynamic properties in Next Generation Impactor (NGI) experiments, such as a smaller median aerodynamic diameter (MMAD), while yielding a higher fine particle fraction (FPF) than spherical particles similar in critical dimensions. They exhibited negligible toxicity to a differentiated macrophage cell line (dTHP-1) for up to 24 h of incubation. The kinetics of the cellular uptake by dTHP-1 cells was assessed via fluorescence microscopy, revealing an uptake-rate dependence on the aspect ratio (AR = l/d); cylinders with high AR were phagocytosed more slowly than shorter rods and comparable spherical particles. This indicates that this novel drug delivery system can modulate macrophage uptake and clearance by adjusting its geometric parameters while maintaining optimal aerodynamic properties and featuring a biodegradable stabilizing matrix.

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.

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

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

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

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

Role of the pharmacist in improving inhaler technique and asthma management in rural areas in Jordan

Introduction

Pharmacists can have a valuable role in educating patients on correct inhaler technique leading to improved asthma management. Rural areas can benefit from the role of the pharmacist considering the barriers found in attending primary health-care facilities.

Objectives

This study aimed to assess the impact of inhaler technique education delivered by pharmacists on patients’ inhaler technique, Asthma Control Test (ACT) score, forced expiratory volume in the first 1 second (FEV₁%), and reliever use (puffs/day).

Methods

A pre–post interventional study was conducted over 6 months from February 2017 to July 2017 in rural areas in Jordan. Asthma patients visiting respiratory clinics and using metered dose inhaler (MDI) or turbuhaler (TH) controlled medication were randomly recruited. Inhaler technique was assessed via published checklists. The ACT, FEV₁%, and reliever use (puffs/day) were assessed. Patients were educated on inhaler technique via demonstration with return demonstration education. All assessments were repeated 3 months post education.

Results

A total of 103 (TH, n=44; MDI, n=59) patients were recruited (mean age=46.5±13.5), 74% females. Patients reported an overuse of their reliever (5.1±4.2 puffs/day). Only 2 patients (1.9%) had well-controlled asthma, while the rest had either moderately (19.4%) or poorly (78.6%) controlled asthma. Patients using the MDI achieved 3.03±4.30 ACT score improvement (p<0.001), which is a clinically significant improvement in control. Patients using the TH achieved a statistically significant improvement of 2.07±4.72 (p=0.031). FEV₁% improved significantly for MDI users (p=0.005) but not for TH users (p=0.097). Reliever use decreased significantly for MDI and TH users.

Conclusion

Asthmatic patients living in rural areas in Jordan reported poor inhaler technique, ACT scores, and FEV₁% scores and high use of reliever medications. Pharmacist-led educational intervention resulted in improved inhaler technique scores, ACT scores, and FEV₁% scores and lowered reliever use over time.

Pharmacokinetics, pharmacodynamics, and clinical efficacy of albuterol RespiClick(™) dry-powder inhaler in the treatment of asthma

INTRODUCTION

Incorrect use of inhaler devices by patients with asthma is common and can adversely affect clinical outcomes. Devices that are straightforward to use are less likely to result in dosing errors and can improve patients' satisfaction with therapy and adherence. A novel dry-powder formulation of the rescue bronchodilator albuterol (salbutamol) administered using a multidose dry-powder inhaler (mDPI; RespiClick™) has recently been approved in the USA.

AREAS COVERED

Studies on the albuterol mDPI were identified in searches of PubMed and www.clinicaltrials.gov . Pharmacokinetic, pharmacodynamic, efficacy, and safety data, and patients' experiences with the albuterol mDPI are presented.

EXPERT OPINION

The albuterol mDPI has an efficacy/tolerability profile consistent with other inhaled forms of albuterol, and is reliable, easy to use, and associated with a high level of patient satisfaction. This is the first albuterol dry-powder inhaler (DPI) to become available in the USA, with most other formulations being delivered using a pressurized metered-dose inhaler (pMDI). The availability of a breath-actuated device avoids the challenge of coordinating actuation and breathing when using pMDIs, and could simplify treatment for patients also using a DPI for controller medication. Additional features of RespiClick, such as an integrated dose counter and minimal pre-inhalation preparation, facilitate its use.

Efficacy of inhaled medications in asthma and COPD related to disease severity

INTRODUCTION

The administration of medication by inhalation has become the most important route in treating airway diseases. The efficacy of this route depends on several factors like correct inhalation techniques, compliance and the size of the particles. The flow properties and internal flow distribution contribute to the deposition pattern. Areas covered: What has been less well studied is the effect of the internal flow distribution. We know from recent studies that using systemic anti-inflammatory compounds that open up the distal airways redistributes flow internally and enhances the deposition of inhaled particles to the active site of bronchoconstriction or airway inflammation. We discuss this in more detail in this paper, and also make reference to the use of functional respiratory imaging (FRI) that allows for the description of this flow pattern starting from chest CT followed by post processing with segmentation software and the application of fluid dynamics. Expert opinion: The method that was previously validated does show the importance of redistribution of flow in the final clinical results that could be obtained with inhaled medication, especially in more severe obstructive airway diseases. Based on these insights and novel diagnostic tools, patients in end stage respiratory failure would benefit from a personalized approach with inhaled medication.

Performance of Turbuhaler((R)) in Patients with Acute Airway Obstruction and COPD, and in Children with Asthma : Understanding the Clinical Importance of Adequate Peak Inspiratory Flow, High Lung Deposition, and Low In Vivo Dose Variability

The dry-powder inhaler (DPI) Turbuhaler((R)) has been on the market for nearly two decades. Products containing terbutaline, formoterol, budesonide, and the combination budesonide/formoterol are widely used by patients with asthma and COPD. Most patients and physicians find Turbuhaler((R)) easy to use, and local side effects are rare. This is thought to arise from the lack of additives or only small amounts in the formulation, in addition to minimal deposition of the drug in the oropharynx and on the vocal cords during inspiration.The function of Turbuhaler((R)) has frequently been questioned. This article aims to review and clarify some key issues that have been challenged in the literature (e.g. the effectiveness of Turbuhaler((R)) in patients with more restricting conditions), to discuss the importance of lung deposition, and to explain the low in vivo variability associated with Turbuhaler((R)) and the lack of correlation with the higher in vitro variability.Turbuhaler((R)), like other DPIs, is flow dependent to some degree. However, a peak inspiratory flow (PIF) through Turbuhaler((R)) of 30 L/min gives a good clinical effect. These PIF values can be obtained by patients with conditions thought to be difficult to manage with inhalational agents, such as asthmatic children and adult patients with acute severe airway obstruction and COPD. Excellent clinical results with Turbuhaler((R)) in large controlled studies in patients with COPD and acute severe airway obstruction provide indirect evidence that medication delivered via Turbuhaler((R)) reaches the target organ.Due to the large amount of small particles and the moderate inbuilt resistance in Turbuhaler((R)), which opens up the vocal cords during inhalation, Turbuhaler((R)) is associated with a high lung deposition (25-40% of the delivered dose) compared with pressurized metered-dose inhalers (pMDIs) and other DPIs. A good correlation has been found between lung deposition and clinical efficacy. A high lung deposition always results in the best ratio between clinical efficacy and risk of unwanted systemic activity. Studies with Turbuhaler((R)) also show that the in vivo variation in lung deposition is significantly lower compared with a pMDI or, for example, the Diskus((R)) inhaler, and much lower than the in vitro dose variability seen in laboratory tests. Turbuhaler((R)) appears to be a reliable DPI which can be used with confidence by patients with airway diseases, including those with clinical conditions believed to be difficult to manage with inhalational therapy.

Evaluation of in vitro and in vivo flow rate dependency of budesonide/formoterol Easyhaler(®)

BACKGROUND

The Easyhaler(®) (EH) device-metered dry powder inhaler containing budesonide and formoterol is being developed for asthma and chronic obstructive pulmonary disease (COPD). As a part of product optimization, a series of in vitro and in vivo studies on flow rate dependency were carried out.

METHODS

Inspiratory flow parameters via EH and Symbicort(®) Turbuhaler(®) (TH) inhalers were evaluated in 187 patients with asthma and COPD. The 10(th), 50(th), and 90(th) percentile flow rates achieved by patients were utilized to study in vitro flow rate dependency of budesonide/formoterol EH and Symbicort TH. In addition, an exploratory pharmacokinetic study on pulmonary deposition of active substances for budesonide/formoterol EH in healthy volunteers was performed.

RESULTS

Mean inspiratory flow rates through EH were 64 and 56 L/min in asthmatics and COPD patients, and through TH 79 and 72 L/min, respectively. Children with asthma had marginally lower PIF values than the adults. The inspiratory volumes were similar in all groups between the inhalers. Using weighted 10(th), 50(th), and 90(th) percentile flows the in vitro delivered doses (DDs) and fine particle doses (FPDs) for EH were rather independent of flow as 98% of the median flow DDs and 89%-93% of FPDs were delivered already at 10(th) percentile air flow. Using±15% limits, EH and TH had similar flow rate dependency profiles between 10(th) and 90(th) percentile flows. The pharmacokinetic study with budesonide/formoterol EH in healthy subjects (n=16) revealed a trend for a flow-dependent increase in lung deposition for both budesonide and formoterol.

CONCLUSIONS

Comparable in vitro flow rate dependency between budesonide/formoterol EH and Symbicort TH was found using the range of clinically relevant flow rates. The results of the pharmacokinetic study were in accordance with the in vitro results showing only a trend of flow rate-dependant increase in lung deposition of active substances with EH.

Formulation considerations for dry powder inhalers

The market for inhalable dry powder medication has consistently grown over past years. Targeting the lungs has been recognized to offer several advantages compared with oral application of drugs. The successive development of inhalation products has led to advances in local treatment of different respiratory diseases, but has also demonstrated the possibility to utilize the lungs for systemic drug delivery. Since a dry powder inhalation product is always a combination of drug formulation and inhalation device, the requirements for the development of such a system may be particularly complex. Therefore, this review aims to give an overview of the necessary considerations for a successful dry powder inhaler development.

The clinical relevance of dry powder inhaler performance for drug delivery

BACKGROUND

Although understanding of the scientific basis of aerosol therapy with dry powder inhalers (DPIs) has increased, some misconceptions still persist. These include the beliefs that high resistance inhalers are unsuitable for some patients, that extra fine (<1.0 μm) particles improve peripheral lung deposition and that inhalers with flow rate-independent fine particle fractions (FPFs) produce a more consistent delivered dose to the lungs.

OBJECTIVES

This article aims to clarify the complex inter-relationships between inhaler design and resistance, inspiratory flow rate (IFR), FPF, lung deposition and clinical outcomes, as a better understanding may result in a better choice of DPI for individual patients.

METHODS

The various factors that determine the delivery of drug particles into the lungs are reviewed. These include aerodynamic particle size distribution, the inspiratory manoeuvre, airway geometry and the three basic principles that determine the site and extent of deposition: inertial impaction, sedimentation and diffusion. DPIs are classed as either dependent or independent of inspiratory flow rate and vary in their internal resistance to inspiration. The effects of these characteristics on drug deposition in the airways are described using data from studies directly comparing currently available inhaler devices.

RESULTS

Clinical experience shows that most patients can use a high resistance DPI effectively, even during exacerbations. Particles in the aerodynamic size range from 1.5-5 μm are shown to be optimal, as particles <1.0 μm are very likely to be exhaled again while those >5 μm may impact on the oropharynx. For DPIs with a constant FPF at all flow rates, less of the delivered dose reaches the central and peripheral lung when the flow rate increases, risking under-dosing of the required medication. In contrast, flow rate-dependent inhalers increase their FPF output at higher flow rates, which compensates for the greater impaction on the upper airways as flow rate increases.

CONCLUSIONS

The technical characteristics of different inhalers and the delivery and deposition of the fine particle dose to the lungs may be important additional considerations to help the physician to select the most appropriate device for the individual patient to optimise their treatment.

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

BACKGROUND

The characteristics of each inhalation maneuver when patients use dry powder inhalers (DPIs) are important, because they control the quality of the emitted dose.

METHODS

We have measured the inhalation profiles of asthmatic children [CHILD; n=16, mean forced expiratory volume in 1 sec (FEV1) 79% predicted], asthmatic adults (ADULT; n=53, mean predicted FEV1 72%), and chronic obstructive pulmonary disease (COPD; n=29, mean predicted FEV1 42%) patients when they inhaled through an Aerolizer, Diskus, Turbuhaler, and Easyhaler using their "real-life" DPI inhalation technique. These are low-, medium-, medium/high-, and high-resistance DPIs, respectively. The inhalation flow against time was recorded to provide the peak inhalation flow (PIF; in L/min), the maximum pressure change (ΔP; in kPa), acceleration rates (ACCEL; in kPa/sec), time to maximum inhalation, the length of each inhalation (in sec), and the inhalation volume (IV; in liters) of each inhalation maneuver.

RESULTS

PIF, ΔP, and ACCEL values were consistent with the order of the inhaler's resistance. For each device, the inhalation characteristics were in the order ADULT>COPD>CHILD for PIF, ΔP, and ACCEL (p<0.001). The results showed a large variability in inhalation characteristics and demonstrate the advantages of ΔP and ACCEL rather than PIFs. Overall inhaled volumes were low, and only one patient achieved an IV >4 L and ΔP >4 kPa.

CONCLUSION

The large variability of these inhalation characteristics and their range highlights that if inhalation profiles were used with compendial in vitro dose emission measurements, then the results would provide useful information about the dose patients inhale during routine use. The inhalation characteristics highlight that adults with asthma have greater inspiratory capacity than patients with COPD, whereas children with asthma have the lowest. The significance of the inhaled volume to empty doses from each device requires investigation.

Orally inhaled fixed-dose combination products for the treatment of asthma and chronic obstructive pulmonary disease: not simple math

Over the past decade, orally inhaled fixed-dose combination products (FDCs) have emerged as an important therapeutic class for the treatment of asthma and chronic obstructive pulmonary disease. However, the conceptual simplicity of inhaled FDCs belies both the complexity of their development, and the profound advantages they offer patients. The benefits of combining agents are not merely additive, and range from increased compliance via simple convenience to complex receptor-level synergies. Similarly, though, the development challenges often exceed the sum of their parts. FDC formulation and analytical method development is generally more complex than for two monotherapy products. Likewise, FDC clinical programs can easily eclipse those of their monotherapy peers and their inherent complexity is often furthered by the diverse regulatory requirements for worldwide approval. As such, the proposition of developing an orally inhaled FDC for global registration often represents a significant increase in both the potential rewards and assumed risks of drug development.

Dry-powder inhalers in acute asthma

An updated literature search was performed to evaluate the efficacy of rapid-acting β2-agonists delivered via dry powder inhalers in the treatment of moderate-to-severe acute asthma. Databases were searched from 1985 up to December 2012. A total of 23 randomized, double-blind or open clinical studies in acute asthma comparing the efficacy of a dry powder inhaler with a pressurized metered-dose inhaler or a nebulizer, and performed under controlled hospital conditions, were identified. This review found that administration of β2-agonist bronchodilators via dry powder inhalers (formoterol, salbutamol, terbutaline and budesonide/formoterol) was effective during severe asthma worsening and acute asthma attacks, and was as effective as established therapies with a pressurized metered-dose inhaler with or without a spacer, or nebulization. These results ensure that patients can rely upon dry powder inhalers equally well as other inhaler devices during episodes of asthma worsening.

Improving inhaler technique, adherence to therapy and the precision of dosing: major challenges for pulmonary drug delivery

INTRODUCTION

The inhaled route has many advantages, but requires the patient to use, and to master the use of, an inhaler device. Poor inhaler technique and non-adherence to therapy lead to a highly variable lung dose in clinical practice, with subsequent loss of clinical efficacy and wastage of economic resources.

AREAS COVERED

This paper discusses problems of poor inhaler technique, non-adherence to inhaler therapy, other issues relating to the precision of dose delivery, the consequences of these problems and how they can be addressed.

EXPERT OPINION

The precision of dosing by the pulmonary route can be improved by appropriate choice of inhaler device and by education. It is vital to educate patients about their disease, about the importance of taking prescribed medications and about correct inhaler use. One-on-one sessions with healthcare professionals probably represent the most effective educational method. For some drugs and patient groups, inhalers containing small microprocessors may also be used to control inhalation technique, and hence, to obtain a more reproducible lung dose. As the range of drugs delivered by inhalation increases, the need for correct inhaler technique, adherence to therapy and precise dosing becomes more and more important.

Clarifying the dilemmas about inhalation techniques for dry powder inhalers: integrating science with clinical practice

This review integrates pharmaceutical science with routine clinical practice to explain why inhalation manoeuvres through a dry powder inhaler (DPI) should start with a gentle exhalation, away from the inhaler. Place the inhaler in the mouth and ensure the lips form a tight seal. This should be followed by an immediate forceful inhalation that is as fast as possible and continued for as long as the patient can comfortably achieve. Although this is universally accepted, there has been a lot of attention on inhalation flow as an indicator of adequate inspiratory effort. This has led to the wrong assumption that inhalation flows through each DPI should be the same, and that low flows through some DPIs suggest that dose delivery is impaired. Most miss the concept that inhalation flow together with the resistance of the DPI combine to create a turbulent energy which de-aggregates the formulation and provides an effective emitted dose. A low flow through a DPI with high resistance generates the same turbulent energy as fast flow with low resistance. Therefore, depending on the device, different inhalation flows are compatible with potentially effective use. Flow measurements should be a guide to train patients to inhale faster. The focus of inhaler technique training should be the use of the above generic inhalation manoeuvre.

The Genuair® inhaler: a novel, multidose dry powder inhaler

This article reviews the Genuair(®) inhaler, a novel, multidose, breath-actuated dry powder inhaler. The inhaler design includes visual and acoustic feedback to reassure patients that they have taken their medication correctly, a dose indicator and a lock-out mechanism to prevent the use of an empty inhaler. The inhaler has medium airflow resistance and uses an optimised dispersion system to ensure effective deagglomeration of the inhalation powder. In vitro studies have demonstrated that the inhaler delivers a reproducible aerodynamic aerosol quality and is reliable under various thermal and mechanical stress conditions. Further studies in vitro have demonstrated that the total emitted dose and fine particle dose are both consistent over a range of inhalation flows from 45 to 95 l/min, as well as being independent of inhalation volume (2 l vs. 4 l) and storage conditions. In healthy subjects, delivery of aclidinium bromide 200 μg via the inhaler achieved high lung deposition (approximately 30% of the metered dose). A further study has shown that patients with moderate or severe chronic obstructive pulmonary disease can generate sufficient inspiratory airflow through the inhaler to reliably inhale the full dose and reset the inhaler. The inhaler has been used to deliver aclidinium in many clinical trials and the available data indicate that it has high acceptability amongst patients.

Current situation of asthma therapy by allergists in primary medical facilities in Japan

BACKGROUND

To reduce deaths from asthma, further use of inhaled corticosteroids (ICS) in accordance with the guidelines is required. The present study was conducted because specialists are responsible for increasing the use of guidelines, but the current state of asthma care provided by specialists in primary clinical settings has not been clarified.

METHODS

In collaboration with five primary medical facilities throughout Japan, severity of asthma, contents of asthma therapy, and the implementation rate of pulmonary function testing and peak flow measurements were analyzed for 1007 outpatients ≥40 years old with stable bronchial asthma. In all patients, peak inspiratory flow (PIF) was measured during examination.

RESULTS

Either ICS or ICS/long-acting beta 2 agonist (LABA) was used in almost all patients with at least mild persistent asthma. Although treatments adhered to the guidelines, therapeutic steps did not match asthma severity in many patients with mild intermittent asthma. Large gaps existed between facilities that measure pulmonary function and PEF in daily clinical practice and those that do not. While mean PIF value for all subjects was well maintained at 102.0 ± 29.1L/min, some patients may not have been able to inhale efficiently in terms of PIF (5.1% of Turbuhaler® users and 5.7% of Diskhaler® users).

CONCLUSIONS

When stepping down asthma therapy, some confusion in policy may exist, leading to guideline mismatches. Differences in the implementation of pulmonary function and PEF measurements, as indicators for long-term management, need to be minimized among specialists. For maintaining effective inhalation, inspiratory flow should be periodically checked.

Inspiratory flows through dry powder inhaler in chronic obstructive pulmonary disease: age and gender rather than severity matters

BACKGROUND

Dry powder inhalers (DPIs) are inspiratory flow driven and hence flow dependent. Most patients with chronic obstructive pulmonary disease (COPD) are elderly and have poor lung function. The factors affecting their inspiratory flows through inhalers are unclear.

OBJECTIVE

To study peak inspiratory flows (PIFs) and their determinants through a DPI in COPD patients of varying age and severity.

METHODS

Flow-volume spirometry was performed in 93 COPD patients. Maximum PIF rates were recorded through an empty Easyhaler (PIF(EH); Orion Corporation, Espoo, Finland), a DPI that provides consistent dose delivery at inhalation rates through the inhaler of 28 L/min or higher.

RESULTS

The mean PIF(EH) was 54 L/min (range 26-95 L/min) with a coefficient of variation of 7%. All but two patients were able to generate a flow of > or = 28 L/min. In a general linear model, the independent determinants for PIF(EH) were age (P = 0.02) and gender (P = 0.01), and forced expiratory volume in 1 s (FEV(1)) expressed as percent predicted was not a significant factor. The regression model accounted only for 18% of the variation in PIF(EH).

CONCLUSION

In patients with COPD, age and gender are more important determinants of inspiratory flow through DPIs than the degree of expiratory airway obstruction. Most COPD patients with varying age and severity are able to generate inspiratory flows through the test inhaler that is sufficient for optimal drug delivery to the lower airways.

Asthma patients prefer Respimat Soft Mist Inhaler to Turbuhaler

Device satisfaction and preference are important patient-reported outcomes to consider when choosing inhaled therapy. A subset of adults (n = 153) with moderate or severe asthma participating in a randomized parallel-group, double-dummy trial that compared the efficacy and safety of 12 weeks’ treatment with budesonide delivered via Respimat^® Soft Mist™ Inhaler (SMI) (200 or 400 μg bd) or Turbuhaler^® dry powder inhaler (400 μg bd), completed a questionnaire on patient device preference and satisfaction (PASAPQ) as part of a psychometric validation. As the study used a double-dummy design to maintain blinding, patients used and assessed both devices, rating their satisfaction with, preference for, and willingness to continue using each device. The mean age of patients was 41 years, 69% were female and the mean duration of disease was 16 years. Total PASAPQ satisfaction scores were 85.5 and 76.9 for Respimat^® SMI and Turbuhaler^® respectively (p < 0.0001); 112 patients (74%) preferred Respimat^® SMI and 26 (17%) preferred Turbuhaler^®. Fourteen subjects (9%) indicated no preference for either inhaler. Willingness to continue using Respimat^® SMI was higher than that for Turbuhaler^® (mean scores: 80/100 and 62/100, respectively). Respimat^® SMI was preferred to Turbuhaler^® by adult asthma patients who used both devices in a clinical trial setting.

Use of dry powder inhalers in acute exacerbations of asthma and COPD

To investigate whether dry powder inhalers (DPIs) function in a constrained situation, a literature analysis was performed to evaluate the use of DPIs compared with established therapies in the treatment of acute asthma and COPD, irrespective of rapid-acting beta(2)-agonist used. The external databases Medline, Embase, Biosis and Current Contents and AstraZeneca's internal literature database Planet were searched up to April 2008. Only publications or congress abstracts describing clinical trials in patients treated at EDs or hospitals were considered, and then only those in which exacerbation severity (measured as FEV(1)) were included. Fifteen clinical studies met these criteria; twelve in acute asthma and three in acute COPD. For acute asthma, eight studies were double-blind, randomised studies (six in adults and two in children), two were open-label studies (one in adults and one in children), and two were investigational (methacholine challenge) studies. For the acute COPD studies, one was double-blind and randomised, one was single-blind and randomised, and one was open-label. This review found that administration of fast-acting bronchodilators via DPIs, the majority of which were Turbuhaler, is effective during an asthma or COPD worsening. Our literature review finds that DPIs function in patients with acute asthma or COPD equally well as established therapies with other inhaler devices. Patients can therefore rely upon DPIs in the same way that they rely upon other inhaler devices.

Dry Powder Inhalers: Which Factors Determine the Frequency of Handling Errors?

BACKGROUND

Dry powder inhalers are often used ineffectively, resulting in a poor level of disease control.

OBJECTIVES

To determine how often essential mistakes are made in the use of Aerolizer, Discus, HandiHaler and Turbuhaler and to study the effects of age, severity of airflow obstruction and previous training in inhalational technique by medical personnel on the error rate.

METHODS

Two hundred and twenty-four newly referred outpatients (age 55.1 +/- 20 years) were asked how they had been acquainted with the inhaler and to demonstrate their inhalational technique.

RESULTS

The inhaler-specific error rates were as follows: Aerolizer 9.1%, Discus 26.7%, HandiHaler 53.1% and Turbuhaler 34.9%. Compared to Aerolizer, the odds ratio of an ineffective inhalation was higher for HandiHaler (9.82, p < 0.01) and Turbuhaler (4.84, p < 0.05). The error rate increased with age and with the severity of airway obstruction (p < 0.01). When training had been given as opposed to no training, the odds ratio of ineffective inhalation was 0.22 (p < 0.01). If Turbuhaler is used, the estimated risks range from 9.8% in an 18-year-old patient with normal lung function and previous training to 83.2% in an 80-year-old patient with moderate or severe obstruction who had not received any training.

CONCLUSIONS

Dry powder inhalers are useful in the management of younger patients with normal lung function or mild airway obstruction. In older patients with advanced chronic obstructive pulmonary disease, the risk of ineffective inhalation remains high despite training in inhalational technique. A metered-dose inhaler with a spacer might be a valuable treatment alternative in a substantial proportion of these patients.

Do airway clearance mechanisms influence the local and systemic effects of inhaled corticosteroids?

The role of airway clearance in inhaled drug therapy is complex. Disease-induced bronchoconstriction results in a central drug-deposition pattern where mucociliary clearance is most efficient. When drug-induced bronchodilation is achieved, deposition and uptake becomes more peripheral, and because there is less mucociliary clearance in the periphery, this will lead to an unintentional increase in lung exposure and enhance the risk of systemic side effects. In addition, mucociliary clearance is pathologically reduced in both asthma and chronic obstructive pulmonary disease. Among inhaled corticosteroids, rate of dissolution and lung uptake differs considerably. For the slowly dissolving, lipophilic steroids, the contribution of mucociliary clearance to these findings appears significant, and variability in lung and systemic exposure resulting from variable mucociliary function appears to be amplified. In addition, dose optimisation of non-stable asthma becomes more complex. The present review highlights the impact of mucociliary clearance on inhaled corticosteroid disposition and identifies critical areas where more research is needed.

Lung deposition and efficacy of inhaled formoterol in patients with moderate to severe COPD

BACKGROUND

Little is known about the impact of COPD on lung deposition of inhaled drugs and the relationship between lung-dose and response of pulmonary function measurements.

METHODS

Nineteen patients with varying degrees of COPD were randomized to inhale single doses of formoterol (Oxis) Turbuhaler 4.5, 9, 18, and 36 microg in a double blind, placebo-controlled, crossover design. Urinary excreted formoterol during 32 h was used to determine absolute lung deposition. Peak inspiratory flow (PIF) and inhaled volume (IV) were recorded to assess the patients' ability to use Turbuhaler. Efficacy was measured by spirometry, inspiratory capacity (IC), airway conductance (sG(AW)), and absolute lung volumes.

RESULTS

Mean pulmonary bioavailability of formoterol was about 24% of the nominal delivered dose after inhalation for the different treatments. No significant correlations between lung deposition and baseline FEV(1), PIF or IV were shown. All formoterol doses produced statistically significant increases in FEV(1), FVC, IC, and sG(AW) relative to placebo. Linear dose/response relationships were observed for these variables, with more narrow limits of the slopes for the lung-dose/response relationships than for the nominal-dose/response relationships. Moreover, 36 and 18 microg formoterol statistically significantly decreased functional residual capacity (FRC) and residual volume (RV) relative to placebo.

CONCLUSIONS

This study could not show any difference in lung deposition of formoterol inhaled via Turbuhaler between patients with moderate and severe COPD. Moreover, the effect of formoterol on various pulmonary function measurements were more closely related to lung deposition than the inhaled nominal dose.

Effect of Relative Humidity on the Electrostatic Charge Properties of Dry Powder Inhaler Aerosols

PURPOSE

At present, there is no published data examining the effect of relative humidity on the electrostatic charges of dry powder inhaler aerosols. The charging behaviour of two commercial products, Pulmicort and Bricanyl Turbuhalers, were investigated using an electrical low pressure impactor (ELPI).

METHODS

ELPI was successfully modified to disperse the aerosols at 60 l/min. Four doses from each new inhaler were sampled at 15, 40, 65, and 90% RH. Particles deposited on the impactor stages according to their aerodynamic diameters and their charges were measured simultaneously by the electrometers. The drug in each size fraction was quantified using HPLC.

RESULTS

Both products generated bipolar charges. The charging behaviour of the two types of inhaler showed different humidity dependence although the mass output was not significantly affected. The absolute specific charge of budesonide fine particles from Pulmicort was the lowest at 40% RH but increased at lower and higher RHs. In contrast, the terbutaline sulfate fine particles from Bricanyl followed the expected trend of charge reduction with increasing RH.

CONCLUSIONS

The distinct trends of charging of aerosols from Pulmicort and Bricanyl Turbuhalers was explained by differences in hygroscopicity and other physicochemical factors between the two drugs.

Effect of dry powder inhaler resistance on the inspiratory flow rates and volumes of cystic fibrosis patients of six years and older

Several inhaled drugs for use by cystic fibrosis (CF) patients are formulated for nebulizer use only. This therapy is time consuming and includes the risk of contamination of the nebulizers. Dry powder inhalers (DPI) can be an attractive alternative for CF drugs. Inhaled flow rate and volume, and the device resistance are important determinants for optimal dispersion of drug from a DPI. It is important to understand how these variables interact in the CF population in order to properly design a new DPI formulation targeted for these patients. The objective of this study was to assess the inspiratory variables of a representative population of CF subjects 6 years and older with varying degrees of lung disease while inhaling through resistances that simulate DPI devices. Ninety-six stable CF patients were enrolled, ages 6-54 years, FEV(1) 19-126% predicted. Subjects inhaled forcefully through four different resistances (0.019, 0.024, 0.038, and 0.048 kP(0.5)/LPM, respectively), while inspiratory time (IT(DPI)), peak inspiratory flow (PIF(DPI)), and volumes (V(DPI)) were measured. For any resistance, inspired V(DPI) increased with the older age groups; PIF(DPI) was similar between adults and adolescents but lower in the children. Subjects with lower FEV(1) had lower V(DPI) and PIF(DPI). As resistance increased, PIF(DPI) decreased, IT(DPI) increased, with no significant change in V(DPI). At the lowest resistance mean PIF(DPI) was 105 LPM (range 45-163) for all patients; 112 LPM (range 75-163) in adults; and 89 LPM (45-126) in children. Mean inspired V(DPI) was 1.75 L for all patients; 2.2 L (0.8-3.7) in adults; and 1.2 L (0.5-1.8) in children. At the lowest resistance a minimal flow rate of 30, 45, and 60 LPM was attained in 100%, 99%, and 96% of all patients. Volumes of 1.0, 1.5, and 2.0 L were attained by 85%, 57%, and 30% of the patients. At the highest resistance mean PIF(DPI) was 52 LPM (range 26-70) for all patients; 55 LPM (40-70) in adults; and 47 LPM (26-62) in children. Mean inspired V(DPI) was 1.5 L in all patients; 1.9 L (0.9-3.5) in adults and 1.1 L (0.5-2.3) in children. At the highest resistance, a minimal flow rate of 30, 45, and 60 LPM was attained in 99%, 80%, and 22% of all patients. Volumes of 1, 1.5, and 2 L were attained in 84%, 45%, and 23% of the patients. We defined ranges for inspiratory variables in a diverse CF population for a range of device resistances that bracket those of current DPIs. The recorded inspiratory patterns can be used on the bench to design and test new dry powder formulations and devices to target the largest proportion of the CF population.

Peak inspiratory flow rate after methacholine challenge in asthmatic patients and its impact on the effect of formoterol via different inhalers

The goal of the present study was to investigate the bronchodilating effects of 6 and 12 microg formoterol delivered by the Turbuhaler, in comparison to salbutamol 200 microg (metered dose inhaler) and to controls without treatment. After inducing acute and severe bronchial obstruction by means of methacholine challenge, peak inspiratory mouth flow (PIMF) was measured through a stenosis, simulating the internal resistance of the Turbuhaler, with the in-check device. In addition the relationship was studied between PIMF and clinical response in the 3 treatment groups. In the 176 patients methacholine caused a mean fall in FEV(1) of 37.1 +/- 6.9% compared to baseline. Ten minutes after bronchodilator inhalation, FEV(1) improved significantly in all three treatment groups. At 30 minutes after bronchodilator administration, only the salbutamol 200 microg and the formoterol 12 microg groups had a significantly greater increase in FEV1 than controls (0.69 +/- 0.43 l and 0.66 +/- 0.37 l vs 0.38 +/- 0.32 l, p < 0.0005), whereas the formoterol 6 microg group showed no significant improvement (0.41 +/- 0.38 l, p = 0.74). Thirteen patients (7.4%) did not reach a minimal PIMF of 30 l/min through the in-check device after challenge. In the four patients in the formoterol 6 microg group with a PIMF below 30 l/min inhalation did not cause bronchodilation. In conclusion, the results demonstrate that 6 microg formoterol via Turbuhaler leads to less and slower onset of bronchodilation compared to the other groups in our setting. If patients fail to generate a PIMF of 30 l/min, 6 microg formoterol via Turbuhaler may provide inadequate relief in a severe asthma attack.

Dry powder inhalers for pulmonary drug delivery

The pulmonary route is an interesting route for drug administration, both for effective local therapy (asthma, chronic obstructive pulmonary disease or cystic fibrosis) and for the systemic administration of drugs (e.g., peptides and proteins). Well-designed dry powder inhalers are highly efficient systems for pulmonary drug delivery. However, they are also complicated systems, the the performance of which relies on many aspects, including the design of the inhaler (e.g., resistance to air flow and the used de-agglomeration principle to generate the inhalation aerosol), the powder formulation and the air flow generated by the patient. The technical background of these aspects, and how they may be tuned in order to obtain desired performance profiles, is reviewed. In light of the technical background, new developments and possibilities for further improvements are discussed.

Idealhalers or realhalers? A comparison of Diskus and Turbuhaler

Medication for the treatment of asthma and chronic obstructive pulmonary disease should be given locally by inhalation. There is, however, no such thing as an ideal inhaler, or 'Idealhaler', which has all desired properties with no drawbacks. In this short review, we have compared the relative merits of the two most commonly used dry powder inhalers -- Turbuhaler and Diskus. Clinical effect is related to the amount of inhaled drug that reaches the lungs, and this in turn depends on the amount of fine particles generated at inhalation. Turbuhaler is more than twice as effective as Diskus at generating fine particles, and the higher lung deposition with Turbuhaler is accompanied by a lower variability in lung deposition. Compared with Diskus, the lung deposition with Turbuhaler is affected less by factors such as humidity.

Equivalent lung deposition of budesonide in vivo: a comparison of dry powder inhalers using a pharmacokinetic method

AIMS

The aim of this study was to compare lung deposition of budesonide administered from two dry powder inhalers, Giona Easyhaler 200 microg/dose and Pulmicort Turbuhaler 200 microg/dose by utilizing a pharmacokinetic method.

METHODS

This was an open, randomized, crossover study in 33 healthy subjects. The study consisted of four treatment periods separated by at least 4 wash-out days. Equivalence in lung deposition was assessed after a single inhaled 1000 microg (5 x 200 microg) dose of budesonide from Giona Easyhaler and from Pulmicort Turbuhaler. Concomitant oral charcoal administration (40 g) was used to prevent gastrointestinal (GI) absorption of budesonide. The efficacy of the charcoal was studied after oral administration of a budesonide 2 mg capsule. The subjects were trained to inhale the study drugs with controlled flow rates, which resulted in an equal pressure drop (4 kPa) across both inhalers. Venous blood samples for the determination of budesonide concentrations in plasma were drawn before and at predetermined time points up to 8 h after drug administration. Budesonide concentrations in plasma were determined using liquid chromatography-tandem mass spectrometry. Several pharmacokinetic parameters were estimated, the area under the budesonide concentration in plasma vs time curve from dosing to infinity (AUC(0, infinity)) being the primary response variable. Equivalence in lung deposition was concluded if the 90% confidence interval (CI) for the Easyhaler : Turbuhaler ratio of AUC(0, infinity) fell within the limits of 0.8-1.25.

RESULTS

The mean AUC(0,infinity) value after Easyhaler treatment was 3.48 (standard deviation (SD) 0.93) ng ml(-1) h and after Turbuhaler treatment 3.46 (1.13) ng ml(-1) h. The Easyhaler : Turbuhaler AUC(0, infinity) ratio was 1.02 and the 90% CI was from 0.96 to 1.09. The mean C(max) values (SD) for budesonide in plasma after Easyhaler and Turbuhaler treatments were 1.22 (0.41) ng ml(-1) and 1.29 (0.44) ng ml(-1), respectively. There was no statistically significant difference (P = 0.39) between the median t(max) for Easyhaler (30 min) and Turbuhaler treatment (23 min). Charcoal impaired the GI absorption of budesonide by 96%. The occurrence of adverse events was similar during both treatments.

CONCLUSIONS

The results show that the lung deposition of budesonide from Giona Easyhaler 200 microg/dose and Pulmicort Turbuhaler 200 microg/dose dry powder inhalers is equivalent. The charcoal block used to prevent GI absorption of swallowed budesonide was found to be effective.

Factors guiding the choice of delivery device for inhaled corticosteroids in the long-term management of stable asthma and COPD: focus on budesonide

Inhaled corticosteroids (ICSs) have become the mainstay of chronic controller therapy to treat airways inflammation in asthma and to reduce exacerbations in chronic obstructive pulmonary disease. An array of ICSs are now available that are aerosolized by a range of delivery systems. Such devices include pressurized (or propellant) metered-dose inhalers (pMDIs), pMDIs plus valved holding chambers or spacers, breath-actuated inhalers, and nebulizers. More recently, dry-powder inhalers (DPIs) were developed to help overcome problems of hand-breath coordination associated with pMDIs. The clinical benefit of ICSs therapy is determined by a complex interplay between the nature and severity of the disease, the type of drug and its formulation, and characteristics of the delivery device together with the patient's ability to use the device correctly. The ICSs budesonide is available by pMDI, DPI, and nebulizer-allowing the physician to select the best device for each individual patient. Indeed, the availability of budesonide in three different delivery systems allows versatility for the prescribing physician and provides continuity of drug therapy for younger patients who may remain on the same ICSs as they mature.

Dry powder inhalers for optimal drug delivery

Dry powder inhalers (DPIs) have been available for delivering drugs to the lungs for over 30 years. In the last decade there has been a big increase in DPI development, resulting partly from recognised limitations in other types of inhaler device. Many companies are developing DPIs for asthma and chronic obstructive pulmonary disease (COPD) therapy, and there is increasing recognition of the potential role of DPI systems for other therapies, such as inhaled antibiotics and peptides/proteins. Optimised drug delivery may be achieved not only by improvements to devices, but also via more sophisticated formulations that disperse easily in the inhaled air-stream and which may often be delivered by relatively simple inhaler devices. DPIs could become the device category of choice for a wide range of inhaled therapies, involving both local and systemic drug delivery.

Use of inhaler devices in pediatric asthma

Inhalation is the preferred route for asthma therapy, since it offers a rapid onset of drug action, requires smaller doses, and reduces systemic effects compared with other routes of administration. Unfortunately, inhalation devices are frequently used in an empirical manner rather than on evidence-based awareness.A wide variety of nebulizers are available. Conventional jet nebulizers are highly inefficient, as much of the aerosol is wasted during exhalation. However, incorporating an extra open vent into the system has considerably increased the amount of drug that patients receive. Breath-assisted open vent nebulizers limit the loss of aerosol during exhalation, but are dependent on the patient's inspiratory flow. Ultrasonic nebulizers produce a high mass output and have a short nebulization time, but are inefficient for delivering suspensions or viscous solutions. Adaptive aerosol delivery devices release a precise dose that is tailored to the individual patient's breathing pattern. Nebulizers have several drawbacks, and their use should be limited to patients who cannot correctly manage other devices.Pressurized metered-dose inhalers (pMDI) are practical, cheap and multidose. However, there are several problems with their use. Breath-actuated MDI are easy to use and can be activated by very low flow. However, young children may not be able to use them efficiently. Dry powder inhalers (DPI) are portable and easy to use. They are indicated either for rescue bronchodilator therapy or for regular treatment with inhaled corticosteroids and long-acting bronchodilators. The use of spacers reduces oropharyngeal deposition and improves drug delivery to the lung. Spacers do not require patient coordination, but some general rules must be followed for their optimal use.Thus, the choice of a delivery device mainly depends on the age of the patient, the drug to be administered and the condition to be treated. Proper education is also essential when prescribing an inhalation device.