Flow early in the inspiratory manoeuvre affects the aerosol particle size distribution from a Turbuhaler

Real-Time Particle Emission Monitoring for the Non-Invasive Prediction of Lung Deposition via a Dry Powder Inhaler

Although inhalation therapy represents a promising drug delivery route for the treatment of respiratory diseases, the real-time evaluation of lung drug deposition remains an area yet to be fully explored. To evaluate the utility of the photo reflection method (PRM) as a real-time non-invasive monitoring of pulmonary drug delivery, the relationship between particle emission signals measured by the PRM and in vitro inhalation performance was evaluated in this study. Symbicort® Turbuhaler® was used as a model dry powder inhaler. In vitro aerodynamic particle deposition was evaluated using a twin-stage liquid impinger (TSLI). Four different inhalation patterns were defined based on the slope of increased flow rate (4.9-9.8 L/s2) and peak flow rate (30 L/min and 60 L/min). The inhalation flow rate and particle emission profile were measured using an inhalation flow meter and a PRM drug release detector, respectively. The inhalation performance was characterized by output efficiency (OE, %) and stage 2 deposition of TSLI (an index of the deagglomerating efficiency, St2, %). The OE × St2 is defined as the amount delivered to the lungs. The particle emissions generated by four different inhalation patterns were completed within 0.4 s after the start of inhalation, and were observed as a sharper and larger peak under conditions of a higher flow increase rate. These were significantly correlated between the OE or OE × St2 and the photo reflection signal (p < 0.001). The particle emission signal by PRM could be a useful non-invasive real-time monitoring tool for dry powder inhalers.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Exploration of quality criteria for the detection of peak inspiratory flow under different resistance conditions

BACKGROUND

At present, robust quality criteria and methods for the assessment of Peak inspiratory flow meter performance are lacking.

OBJECTIVE

A standard flow-volume simulator for quality control analyses of an inhalation assessment device was utilized with different simulated resistance levels in order to propose a quality testing method and associated standard for this device type.

METHODS

A standard flow-volume simulator was utilized to assess the performance of an In-Check DIAL® (Device I) and an intelligent inhalation assessment device (Device P) at a fixed volume and flow rate. Indices used to evaluate these two instruments included repeatability, accuracy, linearity, and impedance.

RESULTS

Both devices exhibited good repeatability (<± 3 L/min). The difference between test results and standard simulator values for Device P was less than ± 5 L/min at resistance level R1 but higher than ± 5 L/min at resistance levels R2-5, while Device I were greater than 5 L/min at all resistance levels. The relative error for Device P was <± 10% at resistance levels R1, R2, and R4, but > 10% at resistance levels R3 and R5. The relative error values for Device I at all five resistance levels were > 10%. Device P passed the linearity test at the R2 resistance level, while Device I partially passed the linearity test at all five resistance levels.

CONCLUSION

Standard monitoring methods and standards provide a valuable approach to the more reliable clinical assessment and application of these instruments.

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.

Can patients achieve sufficient peak inspiratory flow rate (PIFR) with Turbuhaler® during acute exacerbation of asthma?

INTRODUCTION

Anti-inflammatory reliever (AIR) with or without regular maintenance delivered through Turbuhaler® has been widely recommended in the GINA strategy document. These patients are not prescribed with additional reliever inhalers, but dependent on Turbuhaler^® during acute asthma episodes. The peak inspiratory flow rate (PIFR) is crucial in drug delivery from a dry powder inhaler (DPI) such as Turbuhaler^®. Despite its increasing usage, there are some concerns that patients on Turbuhaler^® are not able to achieve adequate PIFR during acute exacerbation of asthma.

OBJECTIVE

This study aimed to assess the PIFR at resistance settings that matched Turbuhaler^® in patients with acute exacerbation of asthma.

METHODOLOGY

A six-month cross-sectional study was conducted at the Emergency Department (ED) of Hospital Sultanah Bahiyah and Hospital Kulim, Kedah, Malaysia. Adult patients diagnosed with mild to moderate acute exacerbations of asthma were recruited. The PIFRs were measured using the In-Check DIAL G16 that was set to simulate the resistance of Turbuhaler^® (R3). The PIFRs were assessed before (pre) and after (post) the initial bronchodilator (BD) treatment at the ED. The minimal required PIFR was defined as flow rates ≥ 30 L/min while a PIFR of 60 L/min was considered as optimal.

RESULTS

A total of 151 patients (81 females and 70 males) were recruited. The mean age was 37.5 years old with a range between 18 and 79 years old. The results showed that 98% (n = 148) of patients managed to achieve the minimal PIFR required for pre-BD. The mean PIFR pre-BD was 60 ± 18.5 L/min and post-BD was 70 ± 18.5 L/min. Furthermore, more than half (54%, n = 82) of the patients recorded PIFR ≥ 60 L/min during pre-BD, and about three-quarters (71%, n = 92) achieved PIFR ≥ 60 L/min post-BD. The PIFR showed a moderate correlation with peak expiratory flow rate (PEFR) (r = 0.55, 95% CI: 0.43-0.65, p < 0.001).

CONCLUSION

The majority of patients with asthma in the present study were able to achieve sufficient PIFR from Turbuhaler^® during mild to moderate acute exacerbations.

Characterization of dry powder inhaler performance through experimental methods

Experimental methods provide means for the quality control of existing DPIs and for exploring the influence of formulation and device parameters well in advance of clinical trials for novel devices and formulations. In this review, we examine the state of the art of in vitro testing of DPIs, with a focus primarily on the development of accurate in vitro-in vivo correlations. Aspects of compendial testing are discussed, followed by the influence of flow profiles on DPI performance, the characterization of extrathoracic deposition using mouth-throat geometries, and the characterization of regional thoracic deposition. Additional experimental methods that can inform the timing of bolus delivery, the influence of environmental conditions, and the development of electrostatic charge on aerosolized DPI powders are reviewed. We conclude with perspectives on current in vitro methods and identify potential areas for future investigation, including the estimation of variability in deposition, better characterization of existing compendial methods, optimization of formulation and device design to bypass extrathoracic deposition, and the use of novel tracheobronchial filters that aim to provide more clinically relevant measures of performance directly from in vitro testing.

Optimal Inhalation Flow Pattern from Turbuhaler Predicted by Laser Photometry

Background: The emitted dose (ED) from most dry powder inhalers (DPIs) is almost independent of peak inspiratory flow (PIF) above a certain value, which is specific to the individual DPI. However, the ED of the Turbuhaler^® (TBH) increases linearly with PIF increments. This study investigated the powder clearance and clinical utility of TBH performance features by using the photo-reflection method (PRM), a type of laser photometry. Methods: Pulmicort^® (PLM) (containing budesonide only) and Symbicort^® (SMB) (drugs with lactose particles) were inspired with a ramp-up pattern of several PIF intensities using a vacuum pump. Time trajectories of particle release and PIF were then compared. Results: The particle-release trajectories from both types of DPIs were similar, consisting of a sharp increment phase (∼0.15 seconds) followed by exponential decay. Both onset to the peak of particle-release time and particle-release times were not affected by PIF changes when the PIF was >40 L/min. EDs from both TBHs were linearly related to PIFs, and the slope of the regression equation for SMB was 2.4-fold larger than that of PLM. The peak of the released particles (PK_IED) was also linearly related to PIF. A linear relationship was also observed between ED and PK_IED in both TBHs, and these regression lines overlapped. Conclusion: EDs from the TBH were dependent on PK_IED. Therefore, rapid, initially strong, and deep inhalation should be advised while using the TBH. PRM could measure the fine and small amount of particles released from the TBH.

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.

Inspiratory flow patterns with dry powder inhalers of low and medium flow resistance in patients with pulmonary arterial hypertension

Inhalation profiles to support use of dry powder inhalers for drug delivery in patients with pulmonary arterial hypertension have not been reported. We aimed to evaluate the inspiratory flow pattern associated with low and medium flow resistance dry powder inhaler devices (RS01-L and RS01-M, respectively) in patients with pulmonary arterial hypertension. This single-center study enrolled patients with pulmonary arterial hypertension associated with connective tissue disease (n = 10) and idiopathic pulmonary arterial hypertension (n = 10) to measure the following inhalation parameters: inspiratory effort (kPa), peak inspiratory flow rate (L/min), inhaled volume (L), and flow increase rate (L/s²) using the two devices. We identified a trend toward higher mean pulmonary artery pressure in the idiopathic pulmonary arterial hypertension group (50 ± 13 mmHg vs. 40 ± 11 mmHg in pulmonary arterial hypertension associated with connective tissue disease; p = 0.077). On average, peak inspiratory flow rate was higher with RS01-L vs. RS01-M (84 ± 19.7 L/min vs. 70.4 ± 13.2 L/min; p = 0.015). In the overall group, no differences between RS01-L and RS01-M were observed for inhaled volume, inspiratory effort, or flow increase rate. Inhaled volume with RS01-L was higher in pulmonary arterial hypertension associated with connective tissue disease vs. idiopathic pulmonary arterial hypertension patients: 1.6 ± 0.4 L vs. 1.3 ± 0.2 L; p = 0.042. For the RS01-L, inhaled volume correlated with forced expiratory volume in one second (r = 0.460, p = 0.030) and forced vital capacity (r = 0.507, p = 0.015). In patients with pulmonary arterial hypertension associated with connective tissue disease using RS01-L, both inspiratory effort and flow increase rate were highly correlated with pulmonary vascular compliance (r = 0.903, p = 0.0001 and r = 0.906, p = 0.0001; respectively); while with RS01-M, inspiratory effort was highly correlated with pulmonary vascular compliance (r = 0.8, p = 0.001). Our data suggest that the use of RS01-L and RS01-M dry powder inhaler devices allowed adequate inspiratory flow in pulmonary arterial hypertension patients. The correlation between flow increase rate and pulmonary vascular compliance in pulmonary arterial hypertension associated with connective tissue disease deserves further investigation.

Peak Inspiratory Flow as a Predictive Therapeutic Biomarker in COPD

Biomarkers in COPD may be clinical (prior exacerbation history), physiologic (FEV₁), or blood based (eosinophil count or fibrinogen level). Recent interest in using biomarkers to predict response to therapy in clinical practice has emerged. The benefits of inhaled therapy depend on the correct use of the inhaler, including an appropriate inspiratory flow. Of the available delivery systems, dry powder inhalers are unique because they have an internal resistance, are breath actuated, and are flow dependent. Ideally, the user inhales "forcefully" to generate turbulent energy (determined by an individual's inspiratory flow and the resistance of the device) within the device that disaggregates the powder so that the individual inhales the medication particles into the lower respiratory tract. Because of specific features of dry powder inhalers and the required optimal inspiratory flow, an unmet need exists to identify individuals who are likely or unlikely to benefit from dry powder medications. Peak inspiratory flow, defined as the maximum airflow generated during inhalation against the simulated resistance of a dry powder inhaler, is a physiologic measure that has biological plausibility, has good test characteristics (repeatability and reliability), and is generalizable. Current evidence supports peak inspiratory flow as a predictive therapeutic biomarker to optimize therapy in both outpatients with COPD as well as those hospitalized for an exacerbation before discharge. This approach is consistent with the precepts of precision medicine, which considers differences in a person's biological features, exposure, and lifestyle to prevent and treat disease.

The impacts of coal dust on miners' health: A review

As one of the most important energy resources in the world, coal contributes a great deal to the world economy. Coal mining and processing involve multiple dust generation processes including coal cutting, transport, crushing and milling etc. Coal dust is one of the main sources of health hazard for the coal workers. Exposure of coal dusts can be prevented through administrative controls and engineering controls. Ineffective control of coal dust exposure can harm coal workers' health. Although many efforts have been made to eliminate these threats, recent years have seen an unexpected increase in coal workers' pneumoconiosis (CWP) in Appalachian basin in US. To explore the reasons for this phenomenon, in this review, we first reviewed the historical studies on coal mine dust including the regulation and engineering controls. Then, the effects of coal dust on human health was comprehensively reviewed. Next, the effects of nanoparticles on human health were reviewed, with an emphasis on toxicity of nanoparticles such as carbon nanotubes in other industries. From all this information, we hypothesize that nano-sized coal dust has contributed to the increase of CWP prevalence in recent years. As no research has been reported in this area, four directions which may need further investigation and future studies are recommended in this review. They include: 1) Systematic characterization of physicochemical properties of nano-size coal dust; 2) Toxicity and pathogenesis of nano-sized coal dust; 3) Development of real-time monitoring technology and equipment for nano-sized coal dust; 4) Development of exposure control technology and equipment. The intent of this review paper is to demonstrate the variation of coal dust properties and their impact on the mine worker's health. We suggest that the impact of nano-sized coal mine dust on miner's health has not yet been understood well and further improvements are necessary.

The role of inspiratory flow in selection and use of inhaled therapy for patients with chronic obstructive pulmonary disease

Inhalation therapy is the mainstay of chronic obstructive pulmonary disease management, and inhaler selection can have a profound impact on drug delivery and medication adherence, as well as on treatment outcomes. Although multiple delivery systems, such as pressurized metered-dose inhalers, dry powder inhalers, slow-mist inhalers, and nebulizers, are available, clinical benefits achieved by patients rely on effective delivery of the inhaled medication to the airways. Among several factors influencing drug deposition, inspiratory flow is one of the most important. Inspiratory flow impacts drug delivery and subsequent clinical efficacy, making it necessary to adequately train patients to ensure correct inhaler use. Peak inspiratory flow is the maximal airflow generated during a forced inspiratory maneuver. Health care professionals need to select the appropriate delivery system after carefully considering patient characteristics, including lung function, optimal inspiratory flow, manual dexterity, and cognitive function. Herein, the role of inspiratory flow in the selection and use of inhaled therapy in patients with COPD is reviewed.

Real-life budesonide and formoterol dose emission from the medium and high strength fixed dosed combinations in a Spiromax® dry powder inhaler using inhalation profiles from patients with chronic obstructive pulmonary disease

Dry powder inhalers (DPIs) are passive devices used to administer inhaled medication for the management of asthma and chronic obstructive pulmonary disease (COPD). DPIs require patients to generate a sufficient internal turbulent airflow force during each inhalation to deaggregate the powdered drug formulation into an emitted dose containing particles with the greatest likelihood of lung deposition. This internal force is generated by the interaction between the user's inhalation flow and the resistance of the DPI. Traditional compendial in vitro methods of measuring dose emission use a vacuum pump to simulate inhalation. We have adapted this in vitro method by replacing the square wave inhalation profile generated by a vacuum pump with the inhalation profiles of patients using an empty DPI. This method enables accurate assessment of the actual dose they would have inhaled. In the present study, real-life inhalation profiles were selected from 15 patients with COPD who inhaled through an empty placebo Spiromax® DPI. Ex vivo dose emissions were measured for the medium (emitted dose of 160 μg/4.5 μg) and high-strength (320 μg/9 μg) budesonide/formoterol formulations from the Spiromax DPI. These profiles were used to investigate the effect of the primary inhalation parameter-peak inhalation flow (PIF). Some profiles were modified to isolate other inhalation parameters (namely, inhaled volume [V_in] and acceleration rate of the inhalation maneuver [ACIM]). Both the medium-strength and high-strength DuoResp Spiromax displayed flow-dependent dose emission. When the PIF of a patient's inhalation maneuver increased from 26.8 L/min to 69.7 L/min, there was a significant (p < 0.05) effect on the dose-emission characteristics of the medium-strength and high-strength DuoResp Spiromax. At each PIF, an increase in V_in from approximately 500 mL to 2000 mL had no effect on the dose-emission characteristics of either strength. However, at each V_in there was a significant (p < 0.05) effect on the dose-emission characteristics as PIF increased. The effect of ACIM on the dose-emission characteristics was small. The ex vivo methodology used in this study provides a practical approach to identify the actual dose a patient might inhale during routine real-life use of the DuoResp Spiromax.

Inspiromatic-safety and efficacy study of a new generation dry powder inhaler in asthmatic children

BACKGROUND

Dry powder inhalers (DPI) are effective but forceful inhalation required to fluidize the powder may be difficult for children and patients with airway disease. Inspiromatic is a new generation active DPI that actively suspends drugs in synchrony with inhalation. We evaluated safety and efficacy of Formoterol delivery via Inspiromatic, compared to Aerolizer, a conventional DPI, in pediatric asthmatic subjects.

METHODS

A phase I/II, randomized, single-center, double-blind, double-dummy, placebo-controlled, cross-over study. Subjects aged 8-18 years with FEV₁ 40-80% predicted were included. Patients were randomized to inhale Formoterol via the Inspiromatic, immediately followed by the placebo via the Aerolizer or vice versa, in a double-blind fashion. Spirometry, blood pressure, and heart rate were measured at baseline and 15, 30, and 60 min after drug administration. Capsule emptying, comfort of use, confidence in efficacy, and patient satisfaction were assessed. At a subsequent visit, three months later, patients inhaled the active drug via the other DPI.

RESULTS

Twenty-nine patients, aged 12.6 (±2.3) years, mean (SD), completed the study. Baseline FEV₁ was 69.1 (±6.7) % at visit one and 65.3 (±9) % at visit two. Maximal FEV₁ increase was 16.6 (±7.1) % with Inspiromatic and 15.5 (±7.5) % with Aerolizer (P = 0.47). No differences in heart rate or blood pressure were observed; 24/28 capsules were emptied using the Inspiromatic and 19/28 with the Aerolizer (P = 0.5); 21/28 preferred the Inspiromatic and 7/28 the Aerolizer (P < 0.001). There were no adverse events.

CONCLUSIONS

Formoterol inhalation via the Inspiromatic is safe and as efficacious as with the Aerolizer. The device is well accepted by asthmatic subjects.

[Evaluation of inhaler techniques in patients with asthma and chronic obstructive disease]

INTRODUCTION

The correct method for using inhalation devices (DI) is essential to optimize treatment efficacy.

OBJECTIVE

To evaluate the method of inhalation technique, study the correlations with patient characteristics, disease, treatment and measure the impact of direct and individual educational method, centered on the use of technical DI, on improving this technique and control of the disease.

METHOD

Prospective study of 54 patients. The therapeutic education program included 3 levels of action: identifying errors in the inhalation technique, demonstrating the inhalation technique and evaluation of therapeutic education.

RESULT

The most used DI was metered-dose inhalers (AD) (66.67%). The average error was 4.63 errors/patient for AD and 5.11 for dry powder inhalers. The main factors related to the misuse of DI were lower advanced level of education and age. The therapeutic education has significantly improved the number of errors/patient with improved asthma control (P<0.05) and COPD assessment test (CAT) in the case of COPD.

CONCLUSION

Our study confirms the important role of therapeutic education focused on inhalation techniques in improving the use of DI technology and the evolution of asthma and COPD.

Assessment of the Power Required for Optimal Use of Current Inhalation Devices

Background: Inhalation of medications is the cornerstone in the treatment of patients with lung diseases. A variety of inhalation devices exists and each device has specific requirements to achieve optimum inhalation of the drug. The goal of this study was to establish a clear overview on performance requirements of standard inhalation devices that should be met by the patient's breathing power and to develop a new method to measure the individual performance data. Materials and Methods: An optimum and still acceptable required breathing power (P in watts) was calculated for each device with the aid of individual device flow rates (determined by a literature search) and the flow resistances (by measuring the pressure drop over the different inhalation devices). For the in vivo part of the study, peak inspiratory flow and peak inspiratory pressure drop were measured in 21 adult patients with asthma or chronic obstructive pulmonary disease and healthy volunteers and the peak inspiratory power (PIPO in watts) was calculated. Results: Nearly no power is needed to achieve optimum results when using pressurized metered dose inhalers. For dry powder inhalers, the required power depends on the specific inhalation device. Conclusions: Inhalation devices impose differing demands on the inspiratory breathing power of patients. To ensure adequate use of the different devices, a cheap and simple assessment of patients' PIPO may be one option.

Real life dose emission characterization using COPD patient inhalation profiles when they inhaled using a fixed dose combination (FDC) of the medium strength Symbicort® Turbuhaler®

The dose emitted from dry powder inhalers (DPI) is inhalation flow dependent and so varies with the peak inhalation flow (PIF) of a patient's inhalation maneuver (IM). Dose emission could also be affected by other IM parameters-the inhaled volume (V_in) and the initial acceleration rate of the IM (ACIM). We have adapted the compendial method for in-vitro DPI determinations so that inhalation profiles replace the inhalation square profile generated by a vacuum pump. These real-life patient inhalation profiles were measured when 18 COPD patients inhaled through an empty placebo Symbicort^® Turbuhaler^®. They have been used to identify the dose emission characteristics from a fixed dosed combination of 200μg budesonide plus 6μg formoterol Turbuhaler^®. To isolate each inhalation parameter some profiles were modified to provide a further 9 profiles to study the influence of V_in and 27 to identify the effect of ACIM. The fine particle dose, total emitted dose and mass median aerodynamic diameter were significantly (p<0.05) influenced by PIF (p<0.05) whereas ACIM and V_in had only a small effect. The results show the value of this ex-vivo methodology to provide an insight into the dose that each patient would have inhaled during real-life use.

Appropriate use of a dry powder inhaler based on inhalation flow pattern

Background

An optimal inhalation flow pattern is essential for effective use of a dry powder inhaler (DPI). We wondered whether DPI instructors inhale from a DPI with an appropriate pattern, and if not, whether self-training with visual feedback is effective.

Methods

Subjects were 14 pharmacists regularly engaged in instruction in DPI use. A newly designed handy inhalation flow visualizer (Visual Trainer: VT) was used to assess inhalation profiles and to assist in self-training. With a peak inhalation flow rate (PIFR) > 50 L/min, time reaching PIFR (T_PF) < 0.4 s, inhalation volume (V_I) > 1 L, and flow at 0.3 s after the onset of inhalation (F_0.3) > 50 L/min, the pattern was considered optimal.

Results

Using Diskus or Turbuhaler 12 and 10 subjects respectively inhaled with a suitable PIFR. Those with a satisfactory F_0.3 were 10 and 7 respectively. The T_PF was short enough in only 1 and 2 respectively. All 14 subjects inhaled deeply (V_I) through Diskus, and 10 did so through Turbuhaler. In the self-training session, only 3 subjects satisfied all three variables at the first trial, while 2 or 3 trials were required in other subjects. Among the three variables, optimal T_PF was the most difficult to attain. Once a satisfactory inhalation pattern was achieved using one DPI, eleven out of 12 subjects inhaled with a satisfactory pattern through the other DPI.

Conclusion

Visualization of the inhalation flow pattern facilitates the learning of proper inhalation technique through a DPI.

The Impact of Inspiratory Flow Rate on Drug Delivery to the Lungs with Dry Powder Inhalers

Current marketed dry powder inhalers utilize the energy from patient inspiration to fluidize and disperse bulk powder agglomerates into respirable particles. Variations in patient inspiratory flow profiles can lead to marked differences in total lung dose (TLD), and ultimately patient outcomes for an inhaled therapeutic. The present review aims to quantitate the flow rate dependence in TLD observed for a number of drug/device combinations using a new metric termed the Q index. With this data in hand, the review explores key attributes in the design of the formulation and device that impact flow rate dependence. The review also proposes alternative in vitro methods to assess flow rate dependence that more closely align with in vivo observations. Finally, the impact of variations in flow rate on lung function for inhaled bronchodilators is summarized.

Inhalation device requirements for patients' inhalation maneuvers

BACKGROUND

Inhaled drugs are the mainstay of treatment for lung diseases such as asthma and chronic obstructive pulmonary disease. However, failure to use inhalation devices correctly can lead to a poorly controlled status. A vast number of inhalation devices exist and each device has specific requirements to achieve optimum inhalation of the drug. Currently, there is no overview of inhalation requirements considering all devices. This article presents a review of the literature on different inhalation device requirements and incorporates the data into a new inhalation flow algorithm.

METHODS

Data from literature on commercially available inhalation devices were evaluated and parameters, such as inhalation flow rate, flow acceleration, inhalation volume, and inspiration time assessed for the required inhalation maneuver specific to the device. All agreed upon data points were used to develop an inhalation flow algorithm.

RESULTS

The literature analysis revealed availability of robust data for the required inhalation flow characteristics for most devices and thus for the development of an algorithm. For those devices for which these parameters are not published, the minimum required flow criteria were defined based on published data regarding individual aspects of aerosol quality.

CONCLUSIONS

This review provides an overview of inhalation devices available on the market regarding requirements for an acceptable inhalation maneuver and shows which goals should be achieved in terms of inhalation flows. The presented algorithm can be used to develop a new computer based measurement system which could help to test and train patients' individual inhalation maneuvers with their inhalation devices.

In Vitro Comparison of Output and Particle Size Distribution of Budesonide from Metered-Dose Inhaler with Three Spacer Devices during Pediatric Tidal Breathing

OBJECTIVES

The aim of this in vitro study was to determine the delivered dose of budesonide 200mug via a chlorofluorocarbon-free pressurized metered dose inhaler (pMDI) when administered through different spacers in tidal breathing patterns of young children.

METHODS

Tidal breathing was simulated for toddlers and children. Spacers tested were Babyhaler((R)), AeroChamber((R)) Plus small and medium; the pMDI was Budiair((R)) 200microg. Output was measured after one actuation and five inhalations in primed and unprimed spacers. Cumulated output was evaluated after each of five simulated inhalations. Aerosol characteristics - i.e. particle size distribution of the output - were determined in primed spacers with a cascade impactor using high-performance liquid chromatography and UV detection.

RESULTS

Total output from primed spacers after five inhalations was determined between 37.9microg and 40.9microg with little differences between spacers and breathing patterns. About 58-79% of this total output was inhaled with the first breath from the AeroChamber((R)) Plus and about 26% from the Babyhaler((R)). The fine particles <5mum ranged between 87% and 92% of the delivered dose for all three spacers.

DISCUSSION AND CONCLUSION

The nominal dose (200microg) of the Budiair((R)) 200microg inhaler is reduced to 40microg delivered dose or less by using Babyhaler((R)) and AeroChamber((R)) Plus spacers taking five breaths. With a single breath the delivered dose can be reduced further to a minimum of 10microg using the Babyhaler((R)). Clinical studies are warranted in the future for decisions on 'clinical efficacy', safety, and exact dose adjustment.

Effects of ramp-up of inspired airflow on in vitro aerosol dose delivery performance for certain dry powder inhalers

This study investigated the effect of airflow ramp-up on the dose delivery performance of seven dry powder inhalers, covering a broad range of powder formulations and powder dispersion mechanisms. In vitro performance tests were performed at a target pressure drop of 4kPa, using two inspiratory flow ramp-up conditions, representing slow and fast ramp-up of airflow, respectively. The fluidization of bulk powder and aerosol clearance from the inhaler was assessed by laser photometer evaluation of aerosol emission kinetics and measurement of the delivered dose (DD). The quality of aerosol dispersion (i.e. de-agglomeration) and associated lung targeting performance was assessed by measuring the total lung dose (TLD) using the Alberta idealized mouth-throat model. The ratio of DD and TLD under slow/fast ramp conditions was used as a metric to rank-order flow ramp effects. Test results show that the delivered dose is relatively unaffected by flow ramp (DD ratio ~1 for all dry powder inhalers). In contrast, the total lung dose showed significantly more variation as a function of flow ramp and inhaler type. Engineered (spray dried) powder formulations were associated with relatively high TLD (>50% of nominal dose) compared to lactose blend and agglomerate based formulations, which had a lower TLD (7-40% of nominal dose), indicative of less efficient targeting of the lung. The TLD for the Tobi Podhaler was the least influenced by flow ramp (TLD ratio ~1), while the TLD for the Asmanex Twisthaler was the most sensitive to flow ramp (TLD ratio ≪1). The relatively high sensitivity of the Asmanex Twisthaler to flow ramp is attributed to rapid aerosol clearance (from the inhaler) combined with a strong effect of flow-rate on particle de-agglomeration and resulting size distribution.

Evaluation of proficiency in using different inhaler devices among intern doctors

CONTEXT

Doctors may have deficiencies in the ability to use different inhalers, which in turn, can result in improper technique by the patients and poorly controlled asthma and chronic obstructive pulmonary disease (COPD).

AIMS

To evaluate intern doctors' proficiency in using various inhaler devices.

MATERIALS AND METHODS

Seventy interns were evaluated for their proficiency in using pressurized metered dose inhaler (pMDI), pMDI with spacer, rotahaler, turbuhaler, and nebulizer. A structured assessment sheet was scored for identification and preparation of device, administration, coordination, and skill of explanation on a scale of 0-5. Common errors such as failure to shake pMDI before use, inability to identify the empty device, inadequate breath holding, and failure to advise gargles after use were recorded.

RESULTS

pMDI and pMDI with spacer were identified correctly by 89% and 79% of interns. Over 90% could identify rotahaler and nebulizer whereas only 9% could identify turbuhaler. 79% and 60% could prepare pMDI and pMDI with spacer appropriately. Nebulizer preparation was performed correctly by 79% and almost all interns could not prepare turbuhaler. Only one intern administered turbuhaler correctly. About half of the participants knew the correct co-ordination for pMDI and pMDI with spacer. Two interns showed proper co-ordination in using turbuhaler. None could provide correct explanation for turbuhaler usage; whereas 76% and 70% did it for nebulizer and rotahaler, respectively. Only 43% of interns remembered to shake pMDI before use.

CONCLUSIONS

Proficiency in using different inhaler devices amongst interns is poor. It is essential to provide adequate training for inhaler devices usage to medical graduates for proper management of asthma and COPD patients by those future primary care physicians and specialists.

Exhalation immediately before inhalation optimizes dry powder inhaler use

OBJECTIVE

Although exhalation immediately prior to inhalation (EPI) from dry powder inhalers (DPIs) is universally advised, its benefit has not been investigated. The objective of this study to assess the effects of EPI on inhaled flow from a DPI.

METHODS

We measured peak inhaled flow rate (PIFR) and inhaled gas volume of 25 volunteers unfamiliar with DPIs. They inhaled strongly and deeply through a flow meter either with or without EPI before and after connecting Turbuhaler or Diskus.

RESULTS

Median PIFR increased significantly with EPI both without connection to DPIs (178.8 versus 140.4 L min(-1)), and with connection to Diskus (75.6 versus 67.8 L min(-1)), or to Turbuhaler (51.0 versus 48.0 L min(-1)). As a result, the number of subjects whose PIFR exceeded 60 L min(-1) was significantly increased with connection to either Diskus (76 versus 64%) or to Turbuhaler (24 versus 4%). EPI significantly increased median inhaled volume both without connection to DPIs (2.84 versus 1.84 L), and with connection to Diskus (1.95 versus 1.66 L), or to Turbuhaler (1.86 versus 1.28 L). EPI significantly increased F0.2 (flow at 0.2 s after onset of inhalation) and AC30 (flow acceleration at 30 L min(-1)), parameters representing the rate of flow increase during the early phase of inhalation, in all the three groups.

CONCLUSIONS

EPI increases PIFR which may augment drug dispersion and facilitate fine particle generation from a DPI.

Maintaining Control of Chronic Obstructive Airway Disease: Adherence to Inhaled Therapy and Risks and Benefits of Switching Devices

Asthma and chronic obstructive pulmonary disease (COPD) are major obstructive airway diseases that involve underlying airway inflammation. The most widely used pharmacotherapies for asthma and COPD are inhaled agents that have been shown to be effective and safe in these patients. However, despite the availability of effective pharmacologic treatment and comprehensive treatment guidelines, the prevalence of inadequately controlled asthma and COPD is high. A main reason for this is poor adherence. Adherence is a big problem for all chronic diseases, but in asthma and COPD patients there are some additional difficulties because of poor inhalation technique and inhaler choice. Easier-to-use devices and educational strategies on proper inhaler use from health caregivers can improve inhaler technique. The type of device used and the concordance between patient and physician in the choice of inhaler can also improve adherence and are as important as the drug. Adherence to inhaled therapy is absolutely necessary for optimizing patient control. If disease control is not adequate despite good adherence, switching to a more appropriate inhaled therapy is recommended. By contrast, uninformed switching or switching to less user-friendly inhaler may impact disease control negatively. This critical review of the available literature is aimed to provide a guidance protocol on when a switch may be recommended in individual patients.

Revising old principles of inhaled treatment in new fixed combinations for asthma

The major influencing factors on persistent asthma control are the selected treatment(s), the drug delivery route and patient's adherence to therapy, together with the influence of lifestyle (i.e. sedentary habit), comorbid conditions and specific asthma phenotypes. Inhaled corticosteroids (ICS) in combination with a long-acting β2-agonist (LABA) are the gold standard for management of persistent asthma, with maximal local targeting and minimal systemic side effects. Several innovative inhaler devices have been developed for effective local drug administration and good patient compliance to therapy. Recently, a new ICS/LABA fixed combination, formulated with fluticasone propionate (FP) and formoterol fumarate (FF), has been proposed for maintenance treatment of asthma in adults and adolescent patients. FP/FF combines the anti-inflammatory and bronchodilating properties of powerful compounds in a single inhaler. Its pharmacological characteristics allow rapid speed of onset and dosage flexibility required for step-up and step-down strategies, improving adherence to treatment of asthmatic patients. The efficacy of the FP/FF fixed combination at all dosages in controlling asthma symptoms and the reduced rate of discontinuation have been demonstrated by all randomized trials conducted so far.

Inhalation characteristics of asthma patients, COPD patients and healthy volunteers with the Spiromax® and Turbuhaler® devices: a randomised, cross-over study

BACKGROUND

Spiromax® is a novel dry-powder inhaler containing formulations of budesonide plus formoterol (BF). The device is intended to provide dose equivalence with enhanced user-friendliness compared to BF Turbuhaler® in asthma and chronic obstructive pulmonary disease (COPD). The present study was performed to compare inhalation parameters with empty versions of the two devices, and to investigate the effects of enhanced training designed to encourage faster inhalation.

METHODS

This randomised, open-label, cross-over study included children with asthma (n = 23), adolescents with asthma (n = 27), adults with asthma (n = 50), adults with COPD (n = 50) and healthy adult volunteers (n = 50). Inhalation manoeuvres were recorded with each device after training with the patient information leaflet (PIL) and after enhanced training using an In-Check Dial device.

RESULTS

After PIL training, peak inspiratory flow (PIF), maximum change in pressure (∆P) and the inhalation volume (IV) were significantly higher with Spiromax than with the Turbuhaler device (p values were at least <0.05 in all patient groups). After enhanced training, numerically or significantly higher values for PIF, ∆P, IV and acceleration remained with Spiromax versus Turbuhaler, except for ∆P in COPD patients. After PIL training, one adult asthma patient and one COPD patient inhaled <30 L/min through the Spiromax compared to one adult asthma patient and five COPD patients with the Turbuhaler. All patients achieved PIF values of at least 30 L/min after enhanced training.

CONCLUSIONS

The two inhalers have similar resistance so inhalation flows and pressure changes would be expected to be similar. The higher flow-related values noted for Spiromax versus Turbuhaler after PIL training suggest that Spiromax might have human factor advantages in real-world use. After enhanced training, the flow-related differences between devices persisted; increased flow rates were achieved with both devices, and all patients achieved the minimal flow required for adequate drug delivery. Enhanced training could be useful, especially in COPD patients.

Dry powder inhalers and the right things to remember: a concept review

Dry powder inhalers (DPIs) are widely and increasingly used in clinical practice because they represent a substantial advancement in inhalation technology. The effectiveness of a powdered drug to inhale depends on the inspiratory flow rate generated by the patient and on the turbulence produced by the intrinsic resistance of the DPI. While the inspiratory flow is variable with the patient's ability and conditions, the turbulence is differently sized within each device because depending of its technical design. There are higher - medium-, and low-resistance devices. With low-resistance DPIs, the disaggregation and the microdispersion of the drug highly depend on the patient's inhalation airflow rate, because the role of the resistance-induced turbulence is obviously negligible in these cases. This flow-rate dependency is minimized in the presence of a sufficient regimen of turbulence as in the case of medium-resistance DPIs. Both the disaggregation and the micro-dispersion of the powdered drug are optimized in these circumstances even in the absence of a maximal inspiratory flow rate. The low resistance DPIs should not be regarded as the best performer DPIs because their intrinsic low-resistance regimen requires a higher inspiratory airflow rate and effort, which frequently cannot be achieved by subjects suffering from a disease-induced airflow limitation. Only when the ratio between the inhalation flow rate and the DPI intrinsic resistance is balanced, the speed of the particulate, the distribution of the drug within the lung, and the variability of the effective inhaled dose are optimized.

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.

Comparison of in vitro deposition of pharmaceutical aerosols in an idealized child throat with in vivo deposition in the upper respiratory tract of children

PURPOSE

Deposition of drug emitted from two commercially available inhalers was measured in an in vitro child oral airway model and compared to existing in vivo data to examine the ability of the child model to replicate in vivo deposition.

METHODS

In vitro deposition of drug from a QVAR® pressurized metered dose inhaler (pMDI) and Pulmicort® Turbuhaler® dry powder inhaler (DPI) in an Idealized Child Throat (1) and downstream filter was measured using UV spectroscopy and simulated realistic breathing profiles. Potential effects of ambient relative humidity ranging from 10% to 90% on deposition were also considered.

RESULTS

In vitro QVAR pMDI deposition in the idealized mouth-throat at 50% RH (39.2 ± 2.3% of delivered dose) compared well (p>0.05) with in vivo extrathoracic deposition in asthmatic children age 8 to 14 (45.8 ± 12.3%). In vitro Turbuhaler DPI deposition in the idealized mouth-throat at 50% RH (69.0 ± 1.5%) matched in vivo extrathoracic deposition (p>0.05) in 6 to 16 year old children with cystic fibrosis (70.4 ± 21.2%). The effects of ambient humidity were found to be insignificant for Turbuhaler and minor for QVAR.

CONCLUSIONS

The Idealized Child Throat successfully mimics in vivo deposition data in school age children for the inhalers tested, and may provide a standard platform for optimizing pediatric treatment with inhaled pharmaceutical aerosols.

Particle transport and deposition: basic physics of particle kinetics

The human body interacts with the environment in many different ways. The lungs interact with the external environment through breathing. The enormously large surface area of the lung with its extremely thin air-blood barrier is exposed to particles suspended in the inhaled air. The particle-lung interaction may cause deleterious effects on health if the inhaled pollutant aerosols are toxic. Conversely, this interaction can be beneficial for disease treatment if the inhaled particles are therapeutic aerosolized drugs. In either case, an accurate estimation of dose and sites of deposition in the respiratory tract is fundamental to understanding subsequent biological response, and the basic physics of particle motion and engineering knowledge needed to understand these subjects is the topic of this article. A large portion of this article deals with three fundamental areas necessary to the understanding of particle transport and deposition in the respiratory tract. These are: (i) the physical characteristics of particles, (ii) particle behavior in gas flow, and (iii) gas-flow patterns in the respiratory tract. Other areas, such as particle transport in the developing lung and in the diseased lung are also considered. The article concludes with a summary and a brief discussion of areas of future research.

Handling of Diskus dry powder inhaler in Chinese chronic obstructive pulmonary disease patients

BACKGROUND

The incorrect handling of Diskus inhalers in Chinese patients with chronic obstructive pulmonary disease (COPD) is not well documented.

OBJECTIVE

The present study was conducted to evaluate in detail the handling errors related to the Diskus device, and to elucidate the importance of educating COPD patients on the proper use of the device.

METHODS

A total of 384 COPD patients from a pulmonary clinic in China over a period of 5 years were included in the study. The compliance of COPD patients to the 13 discrete steps of Diskus usage were scored and analyzed by three measures: (1) On day 0, patients were given only a package insert on Diskus, and the handling error rate was assessed. Then the patients were given instruction on the 13-step Diskus procedure until they could demonstrate the proper technique. (2) On days 1, 2, and 3, the observation group was continuously educated on a 13-step procedure, and the percentage of patients who scored 100% for each step was recorded. The control group had no such training. (3) On days 10, 20, and 30, the percentage of all subjects correctly performing the Diskus 13-step inhalation procedure was assessed.

RESULTS

Incorrect handling techniques on Diskus usage were widely distributed among Chinese COPD patients. Step 8 ("Inhale forcefully from the beginning, slowly, deeply, and uniformly during the inspiratory phase until the lungs are full") was the most commonly mishandled step (93.8%). The total score and individual step scores of the patients from the observation group were significantly improved during 3-day continuous education. There was also a significantly higher percentage of correctly performed steps in the observation group than in the control group upon assessment on day 10 (96.24% vs. 85.63%, respectively; p<0.01), day 20 (97.31% vs. 86.09%, respectively; p<0.01), and day 30 (98.19% vs. 87.39%, respectively; p<0.01).

CONCLUSION

Handling errors of the Diskus 13-step inhalation procedure were commonly observed in Chinese COPD patients. Continuous educational interventions and regular supervision by health-care providers are therefore crucial for the optimum use of the Diskus inhaler.

Aerodynamic dose emission characteristics of dry powder inhalers using an Andersen Cascade Impactor with a mixing inlet: the influence of flow and volume

An interaction between device resistance and inhalation flow provides the 'energy' to de-aggregate the metered dose of dry powder inhalers (DPIs). Hence all dry powder inhalers demonstrate flow dependent dose emission but information on this at low flows is not available. We have adapted the compendial method for the Andersen Cascade Impactor (ACI) to include a mixing inlet to determine the aerodynamic dose emission characteristics of a salbutamol Diskus(®) [DSK], Easyhaler(®) [EASY] and Clickhaler(®) [CLICK] and the terbutaline Turbuhaler(®) [TBH] using flows of 10-60 L/min and inhalation volumes of 2 and 4 L. All DPIs demonstrated flow dependent dose emission (p<0.001) but there was no difference in the measurements between 2 and 4 L. The flow dependent dose emission properties of each DPI started to plateau when the pressure change inside each device, during an inhalation, was between 1 and 1.5 kPa. This corresponds to inhalation flows of 40.1-49.1, 25.4-28.9, 23.6-28.9 and 29.7-36.3 L/min through DSK, CLICK, EASY and TBH. The adapted methodology allows measurements at low flows. The results highlight that the compendial methodology to use an inhaled volume of 4 L with the ACI could be replaced by 2 L and that the recommendation to make measurements using a pressure drop of 4kPa should be revised.

From inhaler to lung: clinical implications of the formulations of ciclesonide and other inhaled corticosteroids

Asthma continues to be a global health problem and currently available treatments such as corticosteroids can cause unwanted side effects. Inhaled corticosteroids (ICS) are recommended as first-line therapy for reducing airway inflammation and have a distinct advantage over oral preparations as they provide a direct route of delivery to the lungs. However, local deposition of ICS in the oropharynx can lead to oral candidiasis, dysphonia, and pharyngitis. The pharmaceutical quality is a primary concern of any ICS asthma treatment, with a higher quality product resulting in improved efficacy and safety profiles. The particle size distribution and the spray force velocity of an ICS may directly influence lung deposition, and the spray duration of a device is another important factor when coordinating inhalation. Recent advances in ICS device and formulation technology have resulted in significant improvements in the efficacy of available asthma treatments. In particular, hydrofluoroalkane (HFA) solution technology and the development of smaller particle sizes have resulted in the production of new ICS formulations that have the ability to directly target drug delivery to the site of airway inflammation. Both the ICS formulation and the pressurized metered-dose inhaler device used to administer ciclesonide (CIC) HFA have been developed to treat the underlying chronic inflammation associated with asthma. CIC is administered as a prodrug which is activated in the lungs, leading to minimal oropharyngeal deposition. The small particle size of CIC results in the delivery of a high fraction of respirable particles to the small airways of the lungs, resulting in high lung deposition and continual dose consistency. This review summarizes how CIC administered as an HFA formulation is an effective treatment for asthma.

Dose emission characteristics of placebo PulmoSphere® particles are unaffected by a subject's inhalation maneuver

BACKGROUND

Good compliance to the prescribed dosing regimen and inhaler instructions for use are critical for asthma/chronic obstructive pulmonary disease (COPD) patients to achieve good control of their disease. We investigated the extent to which a system comprising porous particles delivered with a passive dry powder inhaler could be designed to achieve significant reductions in dose inhalation errors.

METHODS

Porous placebo particles were prepared by an emulsion-based spray-drying method (PulmoSphere® technology). The formulations were administered as dry powders with a portable, blister-based dry powder inhaler (Simoon Inhaler). The inhalation profiles of 69 asthma/COPD subjects were determined with an inhaler simulator with resistance comparable to that of the Simoon Inhaler. Powder emptying from the device was assessed by laser photometry. Aerosol performance was assessed on a Next Generation Impactor, and with the idealized Alberta mouth-throat model using both square-wave and subject-inhalation profiles generated in the breathing study.

RESULTS

Virtually all subjects could achieve a pressure drop of at least 1 kPa and an inhaled volume of at least 500 mL with the Simoon Inhaler. In vitro measures of particle deposition were found to be largely independent of the inhalation maneuver (flow rate, inhaled volume, ramp time) across the broad range of inhalation profiles observed in the breathing study. The rapid emptying of powder from the Simoon Inhaler minimizes the impact of dose-related errors, such as failure to exhale before inhalation and failure to breath-hold post inhalation.

CONCLUSIONS

Inertial impaction that is largely independent of a subject's inhalation maneuver can be achieved with a drug/device combination product comprising a porous particle formulation and blister-based inhaler.

[Treatment of distal airways involvement in COPD]

INTRODUCTION

The current pharmacological treatment of COPD provides only partial beneficial effects on symptoms, exercise tolerance, frequency of exacerbations and quality of life. This could be related to poor targeting of the distal airways by current treatments, yet these airways are particularly involved in airflow obstruction and its consequences such as hyperinflation.

BACKGROUND

Many treatments used in COPD could have effects on distal airways, including bronchodilators, corticosteroids, mucolytics and antibiotics. However, these possible effects remain poorly understood.

VIEWPOINTS

New treatments targeting more specifically the mechanisms of inflammation, oxidative stress and tissue remodeling that characterize COPD, could prove useful in its management, but most are still only in the early stages of their development. Advances could also come from improvements in inhalation devices, delivering more of the medication to the distal airways.

CONCLUSIONS

Improvement in the management of COPD could come from progress in terms of both molecules and their mode of administration.

Achieving asthma control in practice: understanding the reasons for poor control

Achieving asthma control remains an elusive goal for the majority of patients worldwide. Ensuring a correct diagnosis of asthma is the first step in assessing poor symptom control; this requires returning to the basics of history taking and physical examination, in conjunction with lung function measurement when appropriate. A number of factors may contribute to sub-optimal asthma control. Concomitant rhinitis, a common co-pathology and contributor to poor control, can often be identified by asking a simple question. Smoking too has been identified as a cause of poor asthma control. Practical barriers such as poor inhaler technique must be addressed. An appreciation of patients' views and concerns about maintenance asthma therapy can help guide discussion to address perceptual barriers to taking maintenance therapy (doubts about personal necessity and concerns about potential adverse effects). Further study into, and a greater consideration of, factors and patient characteristics that could predict individual responses to asthma therapies are needed. Finally, more clinical trials that enrol patient populations reflecting the real world diversity of patients seen in clinical practice, including wide age ranges, presence of comorbidities, current smoking, and differing ethnic origins, will contribute to better individual patient management.

Importance of inhaler devices in the management of airway disease

The delivery of drugs by inhalation is an integral component of asthma and chronic obstructive pulmonary disease (COPD) management. However, even with effective inhaled pharmacological therapies, asthma, particularly, remains poorly controlled around the world. The reasons for this are manifold, but limitations of treatment guidelines in terms of content, implementation and relevance to everyday clinical life, including insufficient patient education, access to health care and cost of medication as well as poor inhaler technique are likely to contribute. Considering that inhalation therapy is a cornerstone in asthma and COPD management, little advice is provided in the guidelines regarding inhaler selection. The pressurised metered dose inhaler (pMDI) is still the most frequently prescribed device worldwide, but even after repeated tuition many patients fail to use it correctly. In addition, the correct technique can be lost over time. Although several improvements in pMDIs such as a change in the propellant and actuation have resulted in improvements in lung deposition, many dry powder inhalers (DPIs) are easier to use. However, these devices also have limitations such as dependency of drug particle size on flow rate and loss of the metered dose if the patient exhales through the device before inhaling. Improvements in using inhalation devices more efficiently, in inhaler design for supporting patient compliance, and advances in inhaler technology to assure drug delivery to the lungs, have the potential to improve asthma and COPD management and control. New and advanced devices are considered being helpful to minimise the most important problems patients have with current DPIs.