Measurement of peak inspiratory flow with in-check dial device to simulate low-resistance (Diskus) and high-resistance (Turbohaler) dry powder inhalers in children with asthma

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

The effects of grid design on the performance of 3D-printed dry powder inhalers

The grid structure is an indispensable part of most dry powder inhalers, but the effects of grid geometry on inhaler performance are rarely reported. This study aims to systemically investigate the influence of grid design on the aerosolization performance of capsule-based inhalers through experiments and computational analysis. In-vitro aerosolization and deposition performance of commercial and 3D-printed customized inhalers with different grid mesh designs were experimentally studied using a Next Generation Impactor (NGI). Flow fields in the inhalers were generated, and average turbulence kinetic energy (TKE) and airstream trajectories were obtained through Computational Fluid Dynamics (CFD) analysis, delineating the effects of the different grid designs. Comparative studies using the commercial inhalers and the 3D-printed inhalers show a slightly better performance for the latter, probably due to the different materials used for the inhalers, confirming the suitability of 3D printing. Experimental results show that intensive grid meshes with a relatively small aperture size are beneficial to enhancing inhaler performance. Computational results illustrate that the intensive grid meshes can reduce vortexed airstreams and increase turbulent kinetic energy at the grids in general, which also supports the experimental results. In summary, inhalers with intensive grid meshes are preferred for capsule-based inhalers to enhance aerosolization performance. These findings have significant implications for the comprehensive understanding of how grid designs influence inhaler performance.

Treating COPD Patients with Inhaled Medications in the Era of COVID-19 and Beyond: Options and Rationales for Patients at Home

COVID-19 has affected millions of patients, caregivers, and clinicians around the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads via droplets and close contact from person to person, and there has been an increased concern regarding aerosol drug delivery due to the potential aerosolizing of viral particles. To date, little focus has been given to aerosol drug delivery to patients with COVID-19 treated at home to minimize their hospital utilization. Since most hospitals were stressed with multiple admissions and experienced restricted healthcare resources in the era of COVID-19 pandemic, treating patients with COPD at home became essential to minimize their hospital utilization. However, guidance on how to deliver aerosolized medications safely and effectively to this patient population treated at home is still lacking. In this paper, we provide some strategies and rationales for device and interface selection, delivery technique, and infection control for patients with COPD who are being treated at home in the era of COVID-19 and beyond.

A path to successful patient outcomes through aerosol drug delivery to children: a narrative review

Although using aerosolized medications is a mainstay of treatment in children with asthma and other respiratory diseases, there are many issues in terms of device and interface selection, delivery technique and dosing, as well as patient and parental education that have not changed for half a century. Also, due to many aerosol devices and interfaces available on the market and the broad range of patient characteristics and requirements, providing effective aerosol therapy to children becomes a challenge. While aerosol delivery devices are equally effective, if they are age-appropriate and used correctly, the majority of aerosol devices require multiple steps to be used efficiently. Unfortunately, many children with pulmonary diseases have problems with the correct delivery technique and do not gain therapeutic benefits from therapy that result in poor disease management and increased healthcare costs. Therefore, the purpose of this paper is to review the current knowledge on aerosol delivery devices used in children and guide clinicians on the optimum device- and interface-selection, delivery technique, and dosing in this patient population. Strategies on how to deliver aerosolized medications in crying and distressed children and how to educate parents on aerosol therapy and promote patient adherence to prescribed medications are also provided. Future directions of aerosol therapy in children should focus on these issues and implement policies and clinical practices that highlight the potential solutions to these problems.

Tiotropium in children and adolescents with asthma

BACKGROUND

Asthma is a major cause of morbidity in children, despite the availability of various treatments. In adults, tiotropium-a long-acting muscarinic antagonist-as add-on therapy to an inhaled corticosteroid with or without a long-acting β₂-agonist provides clinical benefit with a safety profile similar to placebo.

OBJECTIVE

To review published evidence on the efficacy and safety of tiotropium as add-on a long-acting muscarinic antagonist therapy in children and adolescents with asthma that is uncontrolled despite use of an inhaled corticosteroid with or without additional controller medication(s).

METHODS

We searched PubMed from inception until June 12, 2018, for randomized controlled trials of children and adolescents aged 1 to 17 years treated with tiotropium and reporting a primary outcome of any pulmonary function test and a secondary outcome of adverse events.

RESULTS

Overall, 7 randomized controlled trials of 1902 preschool children (aged 1-5 years; n = 102), school-age children (aged 6-11 years; n = 905), and adolescents (aged 12-17 years; n = 895) with moderate to severe asthma were included in the analysis. Once-daily tiotropium (5, 2.5, or 1.25 μg) improved lung function parameters, including peak and trough forced expiratory volume in 1 second, vs placebo. Commonly reported adverse events across treatment groups included asthma worsening or exacerbations, decreased peak expiratory flow rate, nasopharyngitis, viral respiratory tract infection, and respiratory tract infection.

CONCLUSION

Once-daily tiotropium as add-on therapy is efficacious and safe in adolescents and children with moderate to severe asthma. These results support the expanded indication by regulatory authorities for add-on tiotropium in patients 6 years or older.

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

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

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

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

A Practical Approach to Severe Asthma in Children

Severe asthma accounts for only a small proportion of the children with asthma but a disproportionately high amount of resource utilization and morbidity. It is a heterogeneous entity and requires a step-wise, evidence-based approach to evaluation and management by pediatric subspecialists. The first step is to confirm the diagnosis by eliciting confirmatory history and objective evidence of asthma and excluding possible masquerading diagnoses. The next step is to differentiate difficult-to-treat asthma, asthma that can be controlled with appropriate management, from asthma that requires the highest level of therapy to maintain control or remains uncontrolled despite management optimization. Evaluation of difficult-to-treat asthma includes an assessment of medication delivery, the home environment, and, if possible, the school and other frequented locations, the psychosocial situation, and comorbid conditions. Once identified, aggressive management of issues related to poor adherence and drug delivery, remediation of environmental triggers, and treatment of comorbid conditions is necessary to characterize the degree of control that can be achieved with standard therapies. For the small proportion of patients whose disease remains poorly controlled with these interventions, the clinician may assess steroid responsiveness and determine the inflammatory pattern and eligibility for biologic therapies. Management of severe asthma refractory to traditional therapies involves considering the various biologic and other newly approved treatments as well as emerging therapies based on the individual patient characteristics.

Targeting inhaled aerosol delivery to upper airways in children: Insight from computational fluid dynamics (CFD)

Despite the prevalence of inhalation therapy in the treatment of pediatric respiratory disorders, most prominently asthma, the fraction of inhaled drugs reaching the lungs for maximal efficacy remains adversely low. By and large drug delivery devices and their inhalation guidelines are typically derived from adult studies with child dosages adapted according to body weight. While it has long been recognized that physiological (e.g. airway sizes, breathing maneuvers) and physical transport (e.g. aerosol dynamics) characteristics are critical in governing deposition outcomes, such knowledge has yet to be extensively adapted to younger populations. Motivated by such shortcomings, the present work leverages in a first step in silico computational fluid dynamics (CFD) to explore opportunities for augmenting aerosol deposition in children based on respiratory physiological and physical transport determinants. Using an idealized, anatomically-faithful upper airway geometry, airflow and aerosol motion are simulated as a function of age, spanning a five year old to an adult. Breathing conditions mimic realistic age-specific inhalation maneuvers representative of Dry Powder Inhalers (DPI) and nebulizer inhalation. Our findings point to the existence of a single dimensionless curve governing deposition in the conductive airways via the dimensionless Stokes number (Stk). Most significantly, we uncover the existence of a distinct deposition peak irrespective of age. For the DPI simulations, this peak (∼ 80%) occurs at Stk ≈ 0.06 whereas for nebulizer simulations, the corresponding peak (∼ 45%) occurs in the range of Stk between 0.03-0.04. Such dimensionless findings hence translate to an optimal window of micron-sized aerosols that evolves with age and varies with inhalation device. The existence of such deposition optima advocates revisiting design guidelines for optimizing deposition outcomes in pediatric inhalation therapy.

Total emitted dose of salbutamol sulphate at different inhalation flows and inhalation volumes through different types of dry powder inhalers

The aim of the present study was to compare the performance of two different dry powder inhalers (DPIs) at different inhalations volumes and inhalation flows. Ventolin Diskus contain blisters of 200µg salbutamol. To test the TED from Aerolizer, salbutamol in Diskus blister was emptied and placed in size 3 capsules suitable for use with Aerolizer. Total emitted dose (TED) delivered by Diskus and Aerolizer was determined using DPI sampling apparatus after one and two inhalations from the same dose. 10-60L/min inhalation flows at 2 and 4L inhalation volume were used in the determination. At inhalation flow ≤30L/min, two inhalations resulted in higher TED than one inhalation (p < 0.05) and Diskus resulted in higher TED than Aerolizer (p < 0.05). The highest TED was at inhalation flow 40L/min above which the effect of the second inhalation and formula device relation were negligible. Device formula relation is present at low inhalation flow but at flow >30L/min Diskus drug formula can be delivered by Aerolizer with no significant difference in TED produced. For the best TED patients are required to inhale as fast as possible (a minimum of 40L/min). At lower inhalation flow two inhalations results in better emitted dose than one inhalation for both DPIs. So, we recommend patients with poor inspiratory efforts to inhale twice and as hard and deep as possible from each dose as they may not receive much benefit from one inhalation even when using DPI with low resistance (Aerolizer) or medium resistance (Diskus). However, further in-vivo study are required to validate this recommendtation.

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.

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.

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.

Effect of inhaler design variables on paediatric use of dry powder inhalers

Age appropriateness is a major concern of pulmonary delivery devices, in particular of dry powder inhalers (DPIs), since their performance strongly depends on the inspiratory flow manoeuvre of the patient. Previous research on the use of DPIs by children focused mostly on specific DPIs or single inspiratory parameters. In this study, we investigated the requirements for a paediatric DPI more broadly using an instrumented test inhaler. Our primary aim was to assess the impact of airflow resistance on children’s inspiratory flow profiles. Additionally, we investigated children’s preferences for airflow resistance and mouthpiece design and how these relate to what may be most suitable for them. We tested 98 children (aged 4.7–12.6 years), of whom 91 were able to perform one or more correct inhalations through the test inhaler. We recorded flow profiles at five airflow resistances ranging from 0.025 to 0.055 kPa^0.5.min.L⁻¹ and computed various inspiratory flow parameters from these recordings. A sinuscope was used to observe any obstructions in the oral cavity during inhalation. 256 flow profiles were included for analysis. We found that both airflow resistance and the children’s characteristics affect the inspiratory parameters. Our data suggest that a medium-high resistance is both suitable for and well appreciated by children aged 5–12 years. High incidences (up to 90%) of obstructions were found, which may restrict the use of DPIs by children. However, an oblong mouthpiece that was preferred the most appeared to positively affect the passageway through the oral cavity. To accommodate children from the age of 5 years onwards, a DPI should deliver a sufficiently high fine particle dose within an inhaled volume of 0.5 L and at a peak inspiratory flow rate of 25–40 L.min⁻¹. We recommend taking these requirements into account for future paediatric inhaler development.

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.

Performance of dry powder inhalers with single dosed capsules in preschool children and adults using improved upper airway models

The pulmonary administration of pharmaceutical aerosols to patients is affected by age-dependent variations in the anatomy of the upper airways and the inhalation pattern. Considering this aspect, different upper airway models, representing the geometries of adults and preschool children, and a conventional induction port according to the European Pharmacopeia were used for in vitro testing of dry powder inhalers with single dosed capsules (Cyclohaler^®, Handihaler^® and Spinhaler^®). Deposition measurements were performed using steady flow rates of 30 and 60 L/min for the Handihaler^®/Spinhaler^® and 30, 60 and 75 L/min for the Cyclohaler^®. The inhalation volume was set at 1 L. For the Cyclohaler^®, the in vitro testing was supplemented by a pediatric inhalation profile. Slight differences of pulmonary deposition between the idealized adult (11%–15%) and pediatric (9%–11%) upper airway model were observed for the Cyclohaler^®. The applied pediatric inhalation profile resulted in a reduction of pulmonary deposition by 5% compared to steady conditions and indicated the influence of the inhalation pattern on the amount of pulmonary deposited particles. The comparison of two pediatric upper airway models showed no differences. The performance of the Handihaler^® was similar to the Cyclohaler^®. The Spinhaler^® showed an insufficient performance and limited reproducibility in our investigations.

NanoCluster budesonide formulations enable efficient drug delivery driven by mechanical ventilation

Agglomerates of budesonide nanoparticles (also known as 'NanoClusters') are fine dry powder aerosols that were hypothesized to enable drug delivery through ventilator circuits. These engineered powders were delivered via a Monodose inhaler or a novel device, entrained through commercial endotracheal tubes, and analyzed by cascade impaction. Inspiration flow rates and other parameters such as inspiration patterns and inspiration volumes were controlled by a ventilator. NanoCluster budesonide (NC-Bud) formulations had a higher efficiency of aerosol delivery compared to micronized budesonide with NC-Bud showing a much higher percent emitted fraction (%EF). Different inspiration patterns (sine, square, and ramp) did not affect the powder performance of NC-Bud when applied through a 5.0 mm endotracheal tube. The aerosolization of NC-Bud also did not change with the inspiration volume (1.5-2.5 L) nor with the inspiration flow rate (20-40 L/min) suggesting fast emptying times for budesonide capsules. The %EF of NC-Bud was higher at 51% relative humidity compared to 82% RH. The novel device and the Monodose showed the same efficiency of drug delivery but the novel device fit directly to a ventilator and endotracheal tubing connections. The new device combined with NanoCluster formulation technology allowed convenient and efficient drug delivery through endotracheal tubes.

A method of estimating inspiratory flow rate and volume from an inhaler using acoustic measurements

Inhalers are devices employed to deliver medication to the airways in the treatment of respiratory diseases such as asthma and chronic obstructive pulmonary disease. A dry powder inhaler (DPI) is a breath actuated inhaler that delivers medication in dry powder form. When used correctly, DPIs improve patients' clinical outcomes. However, some patients are unable to reach the peak inspiratory flow rate (PIFR) necessary to fully extract the medication. Presently clinicians have no reliable method of objectively measuring PIFR in inhalers. In this study, we propose a novel method of estimating PIFR and also the inspiratory capacity (IC) of patients' inhalations from a commonly used DPI, using acoustic measurements. With a recording device, the acoustic signal of 15 healthy subjects using a DPI over a range of varying PIFR and IC values was obtained. Temporal and spectral signal analysis revealed that the inhalation signal contains sufficient information that can be employed to estimate PIFR and IC. It was found that the average power (Pave) in the frequency band 300-600 Hz had the strongest correlation with PIFR (R(2) = 0.9079), while the power in the same frequency band was also highly correlated with IC (R(2) = 0.9245). This study has several clinical implications as it demonstrates the feasibility of using acoustics to objectively monitor inhaler use.

Outpatient management of asthma in children

The principal aims of asthma management in childhood are to obtain symptom control that allows individuals to engage in unrestricted physical activities and to normalize lung function. These aims should be achieved using the fewest possible medications. Ensuring a correct diagnosis is the first priority. The mainstay of asthma management remains pharmacotherapy. Various treatment options are discussed. Asthma monitoring includes the regular assessment of asthma severity and asthma control, which then informs decisions regarding the stepping up or stepping down of therapy. Delivery systems and devices for inhaled therapy are discussed, as are the factors influencing adherence to prescribed treatment. The role of the pediatric health care provider is to establish a functional partnership with the child and their family in order to minimize the impact of asthma symptoms and exacerbations during childhood.

Assessing the performance of two dry powder inhalers in preschool children using an idealized pediatric upper airway model

High prevalence of pulmonary diseases in childhood requires inhalable medication even for young children. Little is known about the efficiency of aerosol therapy especially in preschool children. One factor which limits the lung dose is the upper airway geometry. Based on clinical data a recently developed idealized pediatric upper airway model (children 4-5 years) was used to investigate the performance of two dry powder inhalers (Easyhaler and Novolizer). In vitro investigations were first examined using steady flow rates and an inhalation volume of 1L. Chosen flow rates were 28, 41 and 60L/min (Easyhaler) and 45, 60 and 75L/min (Novolizer). Afterwards inhalation profiles simulated by an electronic lung were included. The investigations showed high amounts of drug particles (up to 80%) which were deposited in the upper airway model. The pulmonary deposition in vitro using the Easyhaler was about 28% (28-60L/min) and 22% (inhalation profile). Using the Novolizer in vitro pulmonary doses of 8-12% (45-75L/min) and about 5% (inhalation profile) were observed. The idealized model shows good performance reproducibility of dry powder inhalers. We have shown that age-dependent models might be appropriate tools for formulation and device development in pediatric age groups.

Inhaler competence in asthma: common errors, barriers to use and recommended solutions

Whilst the inhaled route is the first line administration method in the management of asthma, it is well documented that patients can have problems adopting the correct inhaler technique and thus receiving adequate medication. This applies equally to metered dose inhalers and dry powder inhalers and leads to poor disease control and increased healthcare costs. Reviews have highlighted these problems and the recent European Consensus Statement developed a call to action to seek solutions. This review takes forward the challenge of inhaler competence by highlighting the issues and suggesting potential solutions to these problems. The opportunity for technological innovation and educational interventions to reduce errors is highlighted, as well as the specific challenges faced by children. This review is intended as a policy document, as most issues faced by patients have not changed for half a century, and this situation should not be allowed to continue any longer. Future direction with respect to research, policy needs and practice, together with education requirements in inhaler technique are described.

Reduced Peak Inspiratory Effort through the Diskus((R)) and the Turbuhaler((R)) due to Mishandling is Common in Clinical Practice

OBJECTIVES

A minimum peak inspiratory flow (PIF) through dry powder inhalers (DPIs) is required for effective drug delivery to the lungs. Some patients are unable to generate the minimally effective PIF through the DPI. However, little information is available about the 'real life' prevalence of reduced peak inspiratory effort through the Diskus((R)) and the Turbuhaler((R)) as a result of mishandling

METHODS

We investigated peak inhalation effort through the Diskus((R)) and the Turbuhaler((R)) by both direct observation and the In-Check Dial((R)), a portable PIF meter, in a large sample of patients consecutively referred to our laboratory who were familiar with these devices. Patients with reduced peak inspiratory effort repeated the PIF measurement after a session of instruction on the need for more forceful effort through the device.

RESULTS

We studied 644 patients (mean age 62 years, 42% female). Of these, 62% had chronic obstructive pulmonary disease and 35% had asthma. The mean baseline forced expiratory volume in 1 second was 53% of predicted. 502 patients were using the Diskus((R)) and 185 the Turbuhaler((R)). Overall, 106 patients (16.5%) showed weak inhalation by direct observation at baseline. Of 44 subjects with weak inhalation through the Turbuhaler((R)), 34 (77%) demonstrated a PIF <30 L/min. Post-counselling, only four patients did not achieve a PIF of at least 30 L/min (p < 0.01). Of 62 subjects with weak inhalation through the Diskus((R)), 37 (60%) had a PIF <30 L/min. Post-counselling, all these subjects achieved a PIF of at least 30 L/min (p < 0.001).

CONCLUSION

A significant number of patients show a reduced peak inspiratory effort through the Diskus((R)) and the Turbuhaler((R)) in real life. Our results indicate that the cause of this deficiency is often mishandling of the device because, after a brief session of instruction on the need for more forceful inhalation, most patients obtained an acceptable PIF rate. A PIF meter may identify patients with inadequately weak inhalation and offer useful feedback for obtaining the best inspiratory effort.

Age-dependent deterioration of peak inspiratory flow with two kinds of dry powder corticosteroid inhalers (Diskus and Turbuhaler) and relationships with asthma control

BACKGROUND

Inhaled corticosteroid (ICS) therapy has improved the quality of life (QOL) for many asthmatics and reduced mortality rates associated with asthma. However, some patients do not obtain therapeutic benefit despite satisfactory adherence.

OBJECTIVES

To determine whether asthmatic patients were using ICS devices appropriately, and to clarify relationships between these results and QOL.

SUBJECTS AND METHODS

We studied 100 adult asthmatics, divided into two groups: 50 patients consecutively registered as using Diskus (fluticasone; D-group) and 50 consecutively registered as using Turbuhaler (budesonide; T-group). We measured peak inspiratory flows (PIFs) using the In-Check Dial device. Subjects also completed the Asthma Control Test for evaluation of QOL.

RESULTS

In the D-group, no patients showed PIF below the optimal range (30-90 L/min), whereas 52% of patients had PIF≥91 L/min. In the T-group, 6% of patients showed PIF over the optimal range (60-90 L/min), and 44% had PIF≤59 L/min. When patients in the T-group were required to deliberately make a maximal inhalation, 14% still had PIF≤59 L/min. The proportion of patients with poor control was significantly greater in the T-group than in the D-group. According to univariate logistic regression analyses, low PIF tended to be associated with poor asthma control in the T-group. No significant correlation was found between PIF and age in the D-group, but PIF decreased significantly with age in the T-group.

CONCLUSIONS

Appropriate measures for patients in whom PIF has been judged as lower than optimal include adequate education for inhalation and/or changing to a different inhalation device. These measures should be kept in mind for elderly asthma patients in particular, where appropriate selection of a corticosteroid inhalation device in the early stages of therapy would also be important.

Delivery devices for the administration of paediatric formulations: overview of current practice, challenges and recent developments

The European Paediatric Formulation Initiative (EuPFI), a group consisting of paediatric formulation experts from industry, academia and clinical pharmacy was founded with the aim of raising awareness of paediatric formulation issues. It is imperative that paediatric medicines can be administered accurately to ensure the correct dose is provided and that the administration device is easy to use and acceptable from the patient's and carer's perspectives. This reflection paper provides an overview of currently available paediatric administration devices and highlights some of the challenges associated with, recommendations and recent developments in delivery devices for the oral, inhaled, parenteral, nasal and ocular administration of paediatric formulations, on behalf of the EuPFI.

Adherence to inhaled corticosteroids: comparison of available therapies

Adherence to daily anti-inflammatory therapy, the cornerstone being inhaled corticosteroids (ICSs), is critical for the control of persistent asthma. Many factors, both behavioral and treatment-related, can affect treatment adherence. In the pediatric population, adherence is often the responsibility of parents/caregivers. Thus, parents may need improved awareness of the major asthma controller medications, especially regarding the efficacy and safety of ICSs; their beliefs or concerns regarding asthma therapy have a bearing on their diligence in encouraging adherence with the prescribed treatment regimen. Dosing complexity and factors relating to inhaler use are also important components of adherence. There are currently 6 ICSs (excluding nebulized ICSs) approved for children in the United States. The purpose of this review is to examine and compare the features of the available ICSs that may influence adherence in the treatment of pediatric asthma.

Sensitivity of Turbutester and Accuhaler tester in asthmatic children and adolescents

BACKGROUND

Dry powder inhalers (DPI) are alternative devices for delivering medication for treatment of asthma. The amount of drug delivery to the lungs is directly influenced by peak inspiratory flow rate (PIFR). A minimum PIFR of -30 L/min is needed for the Turbuhaler and Accuhaler.

METHODS

In order to evaluate the sensitivity of the Turbutester and Accuhaler tester in detecting the minimum and optimum PIFR for the Turbuhaler and Accuhaler in asthmatic children, PIFR was measured using the In-Check Dial through the internal resistance of the Turbuhaler and Accuhaler and compared according to the child's ability to make a whistle sound via both testers.

RESULTS

A total of 259 asthmatic children were studied: 20 pre-school children, aged 5-6 years; 174 school-age children, aged 7-12 years; and 65 adolescents, aged 13-18 years. The sensitivity of the Turbutester and Accuhaler tester to detect optimum PIFR were 98.40% and 97.2%, respectively. In the comparison among age groups, the sensitivity of the Accuhaler tester to detect optimum or minimum PIFR for the Accuhaler was 95%, 97.7% and 95.4%, respectively. The sensitivity of the Turbutester to detect optimum PIFR for the Turbuhaler was 94.4%, 98.8% and 98.5%, respectively. The sensitivity of the Turbutester to detect minimum PIFR for the Turbuhaler was 94.7%, 100% and 100%, respectively. There were no significant differences in percentage of having optimum or minimum PIFR among asthma severity and current device usage in all age groups.

CONCLUSIONS

Most children aged at least 5 years could generate enough PIFR to use dry powder inhaler devices. Both the Turbutester and Accuhaler tester were found to have high sensitivity in detecting optimum and minimum required PIFR.

Mometasone furoate: an inhaled glucocorticoid for the management of asthma in adults and children

Mometasone furoate has been available for clinical use, starting with a dermatologic preparation, for nearly 20 years. An inhaled format of the drug for management of asthma had been in development during the last decade and has been available for clinical use for 6 years as a dry powder inhaler delivering either 100 mcg or 200 mcg per dose. It has a long half-life and is suitable for daily dosing. The drug is approved for use in the USA for the treatment of asthma in patients aged 4 years or over. Mometasone furoate is a topically potent glucocorticoid with a favorable risk-benefit profile. A wide variety of randomized clinical trials have shown the drug to have a clinically beneficial effect on asthma comparable to fluticasone propionate, and to permit the reduction or withdrawal of oral glucocorticoid therapy in patients with asthma. Mometasone furoate has approximately 1% oral bioavailability but does produce systemic glucocorticoid effects from the drug released from the lung and its metabolites. These effects are minimal when mometasone is used appropriately at low or moderate doses.

Rationale for the major changes in the pharmacotherapy section of the National Asthma Education and Prevention Program guidelines

Numerous changes have been incorporated into the new National Asthma Education and Prevention Program's Expert Panel Report 3. In the pharmacotherapy section of the report, many of these changes are minor in that they do not alter the basic philosophy of treatment recommendations from the previous Expert Panel Report but only add new formulations, change dosing or dosage forms, or add discussion of risks. However, 4 major changes have been identified, and the rationales for 3 are discussed in detail here. The treatment of childhood asthma is divided into 2 distinct age groups, infants less than 5 years of age and children 5 to 12 years of age, because of the availability of more data suggesting differences in response in these patients, as well as a relative paucity of quality data in the younger patients. Omalizumab, a humanized mAb to IgE, is the only new entity approved for the treatment of asthma since the previous guidelines, and its recommendations were reviewed. The indication for combination therapy with inhaled corticosteroids and long-acting inhaled beta(2)-agonists (LABAs) has been modified in lieu of the recent black box warning concerning the increased risk of severe asthma exacerbations and death associated with LABA use. However, the inhaled corticosteroids/LABAs are still recommended for patients with moderate-to-severe persistent asthma. The rationale for the continued recommendation is provided.

Monitoring flow rates and retention of inhalation techniques using the in-check dial device in adult asthmatics

The In-Check-Dial (Alliance Tech Medical, Granburg, TX) was used to determine adequacy of inhalation techniques and teaching of two different devices. Retention of adequate techniques, was assessed in 234 moderate to severe asthmatics. Inhalation techniques were assessed at periodic follow-ups divided into less than 1 month return visit, between 1 and 3 months, 3 to less than 6 months, and 6 months to less than 1 year. Proper inhalation techniques worsened at greater than 3 months after the last instruction. The use of the In-Check-Dial is a useful tool in teaching proper technique and monitoring the patient's ability to correctly use inhalation devices.

Aerosol therapy: the special needs of young children

Efficient aerosol therapy in young children is a challenge. The aerosol administration method requires special features, because young children can not perform an inhalation manoeuvre, breath usually through the nose and may be distressed during the administration. The prescribing clinician should be aware of the advantages and disadvantages of the different inhalation devices available, in order to select the proper device for each individual patient. For maintenance asthma therapy in young children the pressurized metered dose inhaler (pMDI) combined with spacer is the first choice for delivering aerosols. A facemask can be attached if a child is unable to breath through the mouth. A small leak of the facemask can reduce the dose delivered dramatically, therefore a good seal is crucial. Lung deposition can be improved by using a pMDI with extra-fine particles. However, even if the most optimal device is chosen, cooperation during administration remains the most important determinant for efficient drug delivery. During crying the dose to the lungs is minimal. Optimal aerosol delivery to the lungs of young children can be achieved with a good facemask seal, good cooperation of the child, with quiet breathing and an aerosol with small particles.