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

Successful Use of Easyhaler® Dry Powder Inhaler in Patients with Chronic Obstructive Pulmonary Disease; Analysis of Peak Inspiratory Flow from Three Clinical Trials

INTRODUCTION

There is increasing pressure to use environmentally friendly dry powder inhalers (DPI) instead of pressurized metered-dose inhalers (pMDI). However, correct inhalation technique is needed for effective inhaler therapy, and there is persistent concern whether patients with chronic obstructive pulmonary disease (COPD) can generate sufficient inspiratory effort to use DPIs successfully. The aims of this study were to find clinical predictors for peak inspiratory flow rate (PIF) and to assess whether patients with COPD had difficulties in generating sufficient PIF with a high resistance DPI.

METHODS

Pooled data of 246 patients with COPD from previous clinical trials was analyzed to find possible predictors of PIF via the DPI Easyhaler (PIFEH) and to assess the proportion of patients able to achieve an inhalation flow rate of 30 l/min, which is needed to use the Easyhaler successfully.

RESULTS

The mean PIF was 56.9 l/min and 99% (243/246) of the study patients achieved a PIF ≥ 30 l/min. A low PIF was associated with female gender and lower forced expiratory volume in 1 s (FEV1), but the association was weak and a statistical model including both only accounted for 18% of the variation seen in PIFEH.

CONCLUSIONS

Based on our results, impaired expiratory lung function or patient characteristics do not predict patients' ability to use DPIs in COPD; 99% of the patients generated sufficient PIFEH for successful dose delivery. Considering the targets for sustainability in health care, this should be addressed as DPIs are a potential option for most patients when choosing the right inhaler for the patient.

TRIAL REGISTRATION

Two of three included trials were registered under numbers NCT04147572 and NCT01424137. Third trial preceded registration platforms and therefore, was not registered.

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.

Combining experimental and computational techniques to understand and improve dry powder inhalers

INTRODUCTION

: Dry Powder Inhalers (DPIs) continue to be developed to deliver an expanding range of drugs to treat an ever-increasing range of medical conditions; with each drug and device combination needing a specifically designed inhaler. Fast regulatory approval is essential to be first to market, ensuring commercial profitability.

AREAS COVERED

: In vitro deposition, particle image velocimetry, and computational modelling using the physiological geometry and representative anatomy can be combined to give complementary information to determine the suitability of a proposed inhaler design and to optimise its formulation performance. In combination they allow the entire range of questions to be addressed cost-effectively and rapidly.

EXPERT OPINION

: Experimental techniques and computational methods are improving rapidly, but each needs a skilled user to maximize results obtained from these techniques. Multidisciplinary teams are therefore key to making optimal use of these methods and such qualified teams can provide enormous benefits to pharmaceutical companies to improve device efficacy and thus time to market. There is already a move to integrate the benefits of Industry 4.0 into inhaler design and usage, a trend that will accelerate.

Patients with asthma or chronic obstructive pulmonary disease (COPD) can generate sufficient inspiratory flows via Easyhaler® dry powder inhaler: a pooled analysis of two randomized controlled trials

Background

To evaluate whether patients of varying ages and lung function with asthma or those with chronic obstructive pulmonary disease (COPD) can achieve sufficient inspiratory flows for effective use of the fixed-dose combination of salmeterol-fluticasone propionate and budesonide-formoterol dispensed with the Easyhaler^® (EH) device-metered, multi-dose dry powder inhaler (DPI).

Methods

A pooled analysis of two randomized, multicenter, crossover, open-label studies (NCT01424137; NCT009849061) was conducted to characterize inspiratory flow parameters across the EH, Seretide Diskus (DI) and Symbicort Turbuhaler (TH) inhalers in patients with asthma and/or COPD of varying severity. The primary endpoint was peak inspiratory flow (PIF) rate through the EH.

Results

The intent-to-treat population comprised 397 patients; 383 patients were included in the per-protocol (PP) population. The mean PIF (standard deviation) values through the EH in patients <18 and ≥18 years of age with asthma and in those with COPD, were similar: 61.4 (11.5), 69.7 (13.5), and 61.9 (13.2) L/min, respectively. These flow rates correspond to pressure drops of 5.05 (1.80), 6.52 (2.34) and 5.19 (2.07) kPa, respectively. In total, 380 (99.2%) of patients in the PP population were able to generate a PIF rate through the EH of ≥30 L/min, which is required to enable consistent dose delivery from the DPI; there was a moderate direct association between age and PIF in younger patients with asthma, but this was inverse and less apparent in adult patients with asthma and/or those with COPD. Height and weight were also moderately correlated with PIF. Stronger associations with PIF were observed for some lung function parameters, particularly native PIF and forced inspiratory vital capacity.

Conclusions

Over 99% of patients with asthma and/or COPD were able to inhale through the EH with an adequate PIF rate, irrespective of age, or severity of airway obstruction. This confirms that patients with asthma and/or COPD can achieve inspiratory flows via the EH DPI that are sufficient for its effective use.

Recent advances in capsule-based dry powder inhaler technology

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

Technological and practical challenges of dry powder inhalers and formulations

In the 50 years following the introduction of the first dry powder inhaler to the market, several developments have occurred. Multiple-unit dose and multi-dose devices have been introduced, but first generation capsule inhalers are still widely used for new formulations. Many new particle engineering techniques have been developed and considerable effort has been put in understanding the mechanisms that control particle interaction and powder dispersion during inhalation. Yet, several misconceptions about optimal inhaler performance manage to survive in modern literature. It is, for example still widely believed that a flow rate independent fine particle fraction contributes to an inhalation performance independent therapy, that dry powder inhalers perform best at 4 kPa (or 60 L/min) and that a high resistance device cannot be operated correctly by patients with reduced lung function. Nevertheless, there seems to be a great future for dry powder inhalation. Many new areas of interest for dry powder inhalation are explored and with the assistance of new techniques like computational fluid dynamics and emerging particle engineering technologies, this is likely to result in a new generation of inhaler devices and formulations, that will enable the introduction of new therapies based on inhaled medicines.

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.

Therapeutic comparison of a new budesonide/formoterol pMDI with budesonide pMDI and budesonide/formoterol DPI in asthma

BACKGROUND

Budesonide/formoterol is an effective treatment for both asthma and chronic obstructive pulmonary disease. This study compared the efficacy and safety of a novel hydrofluoroalkane (HFA) pressurised metered-dose inhaler (pMDI) formulation of budesonide/formoterol with that of budesonide pMDI and budesonide/formoterol dry-powder inhaler (DPI; Turbuhaler).

METHODS

This was a 12-week, multinational, randomised, double-blind, double-dummy study involving patients aged > or = 12 years with asthma. All patients had a forced expiratory volume in 1 s of 50-90% predicted normal and were inadequately controlled on inhaled corticosteroids (500-1600 microg/day) alone. Following a 2-week run-in, during which they received their usual medication, patients were randomised (two inhalations twice daily) to budesonide pMDI 200 microg, budesonide/formoterol DPI 160/4.5 microg or budesonide/formoterol pMDI 160/4.5 microg. The primary efficacy end-point was change from baseline in morning peak expiratory flow (PEF).

RESULTS

In total, 680 patients were randomised, of whom 668 were included in the primary analysis. Therapeutically equivalent increases in morning PEF were observed with budesonide/formoterol pMDI (29.3 l/min) and budesonide/formoterol DPI (32.0 l/min) (95% confidence interval: -10.4 to 4.9; p = 0.48). The increase in morning PEF with budesonide/formoterol pMDI was significantly higher than with budesonide pMDI (+28.7 l/min; p < 0.001). Similar improvements with budesonide/formoterol pMDI vs. budesonide pMDI were seen for all secondary efficacy end-points. Both combination treatments were similarly well tolerated.

CONCLUSIONS

Budesonide/formoterol, administered via the HFA pMDI or DPI, is an effective and well-tolerated treatment for adult and adolescent patients with asthma, with both devices being therapeutically equivalent.

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.