Effect of electrostatic charge, flow, delay and multiple actuations on the in vitro delivery of salbutamol from different small volume spacers for infants

The Potential Use of Cyclosporine Ultrafine Solution Pressurised Metered- Dose Inhaler in the Treatment of COVID-19 Patients

INTRODUCTION

Serious COVID-19 respiratory problems start when the virus reaches the alveolar level, where type II cells get infected and die. Therefore, virus inhibition at the alveolar level would help preventing these respiratory complications.

METHOD

A literature search was conducted to collect physicochemical properties of small molecule compounds that could be used for the COVID-19 treatment. Compounds with low melting points were selected along with those soluble in ethanol, hydrogen-bond donors, and acceptors.

RESULTS

There are severe acute respiratory syndrome coronavirus inhibitors with physicochemical properties suitable for the formulation as an ultrafine pressurised metered-dose inhaler (pMDI). Mycophenolic acid, Debio 025, and cyclosporine A are prime candidates among these compounds. Cyclosporine A (hereafter cyclosporine) is a potent SARS-CoV-2 inhibitor, and it has been used for the treatment of COVID-19 patients, demonstrating an improved survival rate. Also, inhalation therapy of nebulised cyclosporine was tolerated, which was used for patients with lung transplants. Finally, cyclosporine has been formulated as a solution ultrafine pMDI. Although vaccine therapy has started in most countries, inhalation therapies with non-immunological activities could minimise the spread of the disease and be used in vaccine-hesitant individuals.

CONCLUSION

Ultrafine pMDI formulation of cyclosporine or Debio 025 should be investigated for the inhalation therapy of COVID-19.

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.

Heterogeneity of emergency treatment practices in wheezing preschool children

AIM

Our aim was to survey treatment practices used for preschool children with wheezing in emergency rooms (ER) focussing on inhalation device choice and handling, face mask use, salbutamol dosing and written instructions. We sought to assess whether current protocols are in line with published evidence and guidelines.

METHODS

This is a cross-sectional survey done in paediatric ER units located in Finnish municipalities with more than 10 000 inhabitants.

RESULTS

Of the 100 units contacted, 50% responded. More than 50% of the units used nebulisers. Only 13% of the units administered salbutamol in single puffs. More than 30% of the units lacked criteria on face mask use. Poor co-operation had no effect on the dose of salbutamol in 62% of the units. Ensuring tight mask-to-face seal was included in the training in 20% of the units. A written action plan was provided to the caregivers in 28% of the units.

CONCLUSION

ER treatment guidelines for preschool children with wheezing are poorly endorsed. Research is needed to identify approaches to guideline implementation that are specific for primary care. Clinical research should focus on strengthening recommendations that are currently not embraced. ER treatment protocols need to be updated and adherence to guidelines should be re-evaluated.

Application of aerosol therapy in respiratory diseases in children: A Saudi expert consensus

The Saudi Pediatric Pulmonology Association (SPPA) is a subsidiary of the Saudi Thoracic Society (STS), which consists of a group of Saudi experts with well-respected academic and clinical backgrounds in the fields of asthma and other respiratory diseases. The SPPA Expert Panel realized the need to draw up a clear, simple to understand, and easy to use guidance regarding the application of different aerosol therapies in respiratory diseases in children, due to the high prevalence and high economic burden of these diseases in Saudi Arabia. This statement was developed based on the available literature, new evidence, and experts' practice to come up with such consensuses about the usage of different aerosol therapies for the management of respiratory diseases in children (asthma and nonasthma) in different patient settings, including outpatient, emergency room, intensive care unit, and inpatient settings. For this purpose, SPPA has initiated and formed a national committee which consists of experts from concerned specialties (pediatric pulmonology, pediatric emergency, clinical pharmacology, pediatric respiratory therapy, as well as pediatric and neonatal intensive care). These committee members are from different healthcare sectors in Saudi Arabia (Ministry of Health, Ministry of Defence, Ministry of Education, and private healthcare sector). In addition to that, this committee is representing different regions in Saudi Arabia (Eastern, Central, and Western region). The subject was divided into several topics which were then assigned to at least two experts. The authors searched the literature according to their own strategies without central literature review. To achieve consensus, draft reports and recommendations were reviewed and voted on by the whole panel.

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.

Optimal administration of bronchodilators with valved holding chambers in preschool children: a review of literature

Our aim was to synthesize the published literature on factors that potentially affect the delivery of bronchodilators using valved holding chambers (VHC) in preschool children. We also aimed to identify those attributes that are not yet incorporated or clearly stated in the guidelines and those topics that are still lacking sufficient data. There is strong evidence supporting several recommendations in current guidelines. Based on present knowledge, bronchodilators should be delivered by VHC administering each puff separately. Face mask should be omitted as soon as the child can hold the mouthpiece of the VHC tightly between the lips and teeth. Based on the review, we suggest adding a specific note to current guidelines about the effect of chamber volume and the impact of co-operation during drug administration. Calming the child and securing a tight face-to-mask seal is critical for successful drug delivery. There is not enough evidence to make specific recommendations on the most reliable VHC and face mask for children. There is an urgent need for studies that evaluate and compare the effectiveness of VHCs in various clinical settings in wide age-groups and respiratory patterns. In addition, there is insufficient data on ideal chamber volume, material, and effective antistatic treatment. What is Known: • Valved holding chambers (VHC) should not be considered interchangeable when used with pressurized metered dose inhalers (pMDI). • Drug delivery is influenced by VHC volume, aerodynamic and electrostatic properties; mask fit; respiratory pattern and co-operation during inhalation; and the number of puffs actuated. What is New: • The impact of co-operation, VHC volume, and good mask-to-face fit during drug inhalation is not stressed enough in the guidelines. • Studies are urgently needed to evaluate the effectiveness of different VHCs in various clinical settings focusing on VHC electrostatic properties, respiratory patters, face masks, and ideal pMDI+VHC combinations.

Valved holding chamber drug delivery is dependent on breathing pattern and device design

Small children with airway obstruction breathe with very low tidal volumes (V_T) and high respiratory rates (RRs). These extreme respiratory patterns affect drug delivery unpredictably through valved holding chambers (VHCs).

We compared in an in vitro study the effectiveness of two VHCs, one small (140 mL, Optichamber Diamond) and one large (350 mL, Babyhaler) without facemasks, to deliver salbutamol to filters positioned between the VHC mouthpieces and a breathing simulator. Different tidal volumes (from 30 mL to 200 mL) and RRs (25·min^-1 and 50·min^-1) were applied through a breathing simulator.

The amount of salbutamol delivered increased with increasing V_T in both VHCs for both RRs (ρ>0.87 and p<0.001 for both devices at both rates). The effect of RR was not as evident, but drug delivery tended to be higher at the higher rate. Drug delivery was significantly higher through the Optichamber Diamond as compared with the Babyhaler at every combination of RR and V_T up to a 12-fold difference.

We found marked differences in salbutamol delivery between the Babyhaler and Optichamber Diamond VHCs. The delivered dose of salbutamol increased with increasing V_T and RR with both VHCs but with differences related to valve dead spaces. Instead of considering all VHCs equal in clinical paediatric practice, each device should be tested in vitro with respiratory patterns relevant to small children with respiratory difficulties.

Children with respiratory problems are treated with inhaled drugs given via valved holding chambers (VHCs). Efficacy can vary up to 12-fold between devices. The effectiveness of VHCs should be tested in all age groups with different respiratory patterns.http://ow.ly/2Aca30mT2Pa

Usefulness of Nonvalved Spacers for Administration of Inhaled Steroids in Young Children with Recurrent Wheezing and Risk Factors for Asthma

Background

In vitro and scintigraphic studies have suggested that effectiveness of metered-dose inhalers (MDI) with nonvalved spacers (NVS) is similar to that of MDI with valved holding chambers (VHC). Nevertheless, there are no clinical studies that compare these techniques in long-term treatment with inhaled steroids in young children with recurrent wheezing and risk factors for asthma.

Objective

To compare the efficacy of a long-term treatment with Fluticasone Propionate administered by an MDI through both type of spacers, with and without valves, in young children with recurrent wheezing and risk factors for asthma.

Patients and Methods

Outpatient children (6 to 20 months old) with recurrent wheezing and risk factors for asthma were randomized to receive a 6-month treatment with metered-dose inhaler (MDI) of Fluticasone Propionate 125 mcg BID through an NVS or through a VHC. Parents recorded daily their child's respiratory symptoms and rescue medication use.

Results

46 patients of 13.4 ± 5 months old were studied. During the study period, the NVS group (n=25) experienced 3.9 ± 2.4 obstructive exacerbations, and the VHC group (n=21) had 2.6 ± 1.6 (p=0.031). The NVS group had 17.4 ± 14% of days with respiratory symptoms, and the VHC group had 9.7 ± 7% (p=0.019). The NVS group spent 29.8 ± 22 days on albuterol while the VHC group spent 17.9 ± 11 days (p=0.022).

Conclusion

Long-term treatment with inhaled steroids administered by MDI and NVS is less effective than such treatment by MDI and VHC in infants with recurrent wheezing and risk factors for asthma.

Spacer devices for inhaled therapy: why use them, and how?

We present an extensive review of the literature to date pertaining to the rationale for using a spacer/valved holding chamber (VHC) to deliver inhaled therapy from a pressurised, metered-dose inhaler, a discussion of how the properties of individual devices may vary according to their physical characteristics and materials of manufacture, the potential risks and benefits of ancillaries such as valves, and the evidence that they contribute tangibly to the delivery of therapy. We also reiterate practical recommendations for the correct usage and maintenance of spacers/VHCs, which we trust offer practical help and advice to patients and healthcare professionals alike.

A review of the in vitro and in vivo valved holding chamber (VHC) literature with a focus on the AeroChamber Plus Flow-Vu Anti-static VHC

Valved holding chambers (VHCs) reduce the need for inhalation-actuation coordination with pressurized metered dose inhalers (pMDIs), reduce oropharyngeal drug deposition and may improve lung deposition and clinical outcomes compared to pMDIs used alone. While VHCs are thus widely advocated for use in vulnerable patient groups within clinical and regulatory guidelines, there is less consensus as to whether the performance differences between different VHCs have clinical implications. This review evaluates the VHC literature, in particular the data pertaining to large- versus small-volume chambers, aerosol performance with a VHC adjunct versus a pMDI alone, charge dissipative/conducting versus non-conducting VHCs, and facemasks, to ascertain whether potentially meaningful differences between VHCs exist. Inconsistencies in the literature are examined and explained, and relationships between in vitro and in vivo data are discussed. A particular focus of this review is the AeroChamber Plus® Flow-Vu® Anti-static VHC, the most recent iteration of the AeroChamber VHC family.

Scintigraphic Assessment of Deposition of Radiolabeled Fluticasone Delivered from a Nebulizer and Metered Dose Inhaler in 10 Healthy Dogs

Background

Aerosolized medications are increasingly being used to treat respiratory diseases in dogs. No previous studies assessing respiratory tract deposition of radiolabeled aerosols have been performed in conscious dogs.

Hypothesis/Objectives

Assess respiratory tract deposition of radiolabeled, inhalant corticosteroid (fluticasone propionate labeled with ^99mTc) delivered from a nebulizer and metered dose inhaler (MDI) to healthy dogs.

Animals

Ten healthy Foxhounds.

Methods

Prospective, randomized, cross‐over pilot study. Initial inhalation method (nebulizer or MDI) was randomly assigned. Treatments were crossed over after a 7‐day washout period. Treatments initially were performed using sedation. Dogs were imaged using 2‐dimensional planar scintigraphy, with respiratory tract deposition quantified by manual region‐of‐interest analysis. Deposition calculated as percentage of delivered dose. Six of 10 dogs were randomly selected and reassessed without sedation.

Results

Inhalation method had significant effect on respiratory tract deposition (P = 0.027). Higher deposition was achieved by nebulization with mean deposition of 4.2% (standard deviation [SD], 1.4%; range, 1.9–6.1%); whereas MDI treatment achieved a mean of 2.3% (SD, 1.4%; range, 0.2–4.2%). Nebulization achieved higher respiratory tract deposition than MDI in 7 of 10 dogs. No statistical difference (P = 0.68) was found between mean respiratory tract deposition achieved in dogs when unsedated (3.8%; SD, 1.5%) or sedated (3.6%; SD, 1.7%).

Conclusions and Clinical Importance

Study confirms respiratory tract deposition of inhalant medications delivered from a nebulizer and MDI in healthy dogs, breathing tidally with and without sedation. Respiratory tract deposition in these dogs was low compared to reported deposition in adult humans, but similar to reported deposition in children.

Valved Holding Chambers and In Vitro Metered Dose Inhaler Performance: Effects of Flow Rate and Inhalation Delay

BACKGROUND

Multiple factors may influence the performance of a metered dose inhaler (MDI) when used with a valved holding chamber (VHC or "spacer").

METHODS

Andersen Cascade Impactor measurements were conducted for three MDI products and two different VHCs using a specially designed system that accommodated variable delay times between MDI actuation and introduction of the aerosol into the impactor, and allowed reduced flow through the VHC while the impactor was operated at 28.3 L/min. Deposited drug mass and aerodynamic particle size distribution were determined using validated high-performance liquid chromatography (HPLC) methods. A two-level, three-factor full-factorial design of experiments (DOE) design was applied to assess the influences of VHC type, flow rate, and inhalation delay on a total of seven performance characteristics for each MDI product. An experiment without a VHC was added to assess the influence of VHC presence.

RESULTS

DOE study shows the presence and type of VHC are the major influences on emitted dose and respirable fraction. Following the VHC effect, the inhalation delay has the most significant influence on most MDI performance metrics-emitted dose, respirable particle dose and fraction (aerosols between 1.1 and 4.7 μm), and fine particle dose and fraction (aerosols under 4.7 μm).

CONCLUSION

This study illustrates the use of DOE analysis to effectively assess the effects of patient handling parameters (flow rate and inhalation delay) on the performance of MDI drugs when used with a VHC. The results of this study will inform Food and Drug Administration reviewers, the pharmaceutical industry, and healthcare practitioners as to safe and effective use of MDI products when used in conjunction with spacer devices.

Development of an Intelligent Spacer Data Logger System

BACKGROUND

Although delivery of drugs from pressurized metered dose inhalers (pMDIs) via spacer devices is widespread it cannot be assumed that patients take their medication as prescribed or use their spacer appropriately. We developed a Spacer Data Logger device to record patient adherence and whether patients had shaken the pMDI, actuated it soon after shaking, and inhaled a sufficient volume from it.

METHODS

We report an assessment of the Spacer Data Logger to measure and record that the pMDI was adequately shaken, the time to actuation, and the volume "inhaled" from the spacer up to 26 seconds after actuation. The effect of a delay in actuation following shaking on the dose available for inhalation from the spacer and the effect of a delay in extraction of aerosol from the spacer were assessed using different strengths of beclomethasone dipropionate (50 and 100 μg) and fluticasone propionate (50, 125 and 250 μg).

RESULTS

The volumes measured by the Spacer Data Logger were in close agreement with the reference volumes of four simulated breathing patterns. A delay between shaking and actuating the pMDI resulted in a significant increase in the dose available for inhalation after only 4 seconds for the 50 and 250 μg strengths of fluticasone propionate pMDIs (p = 0.004 and p < 0.001, respectively). A delay between actuation of the drug into the spacer and "inhalation" of aerosol from the spacer also resulted in a steady decline in the dose available from the spacer (p < 0.0001).

CONCLUSIONS

These results confirmed the importance of using the pMDI spacer correctly by actuating directly after shaking and inhaling the aerosol from the spacer as soon after actuation as possible to optimize the dose available for inhalation. The Spacer Data Logger should be a useful tool to determine adherence to and "optimum" use of pMDI spacers in patients with asthma and chronic obstructive pulmonary disease (COPD).

Effect of Spacers on the Bipolar Electrostatic Charge Properties of Metered Dose Inhaler Aerosols-A Case Study With Tilade®

Aerosols emitted from metered dose inhalers (MDIs) are generally electrically charged and bipolar in nature. Although a spacer can effectively dampen the charge magnitude of aerosols, the electrostatic interactions between the positively and negatively charged particles and the spacer have not yet been characterized separately. The Bipolar Charge Analyzer (BOLAR) was employed to investigate interactions between the spacer and the charged aerosols. Three individual actuations of Tilade^® MDI were introduced without a spacer and through an antistatic AeroChamber Plus^® Z Stat^®, an uncoated and a detergent-coated AeroChamber Plus^® spacer into the BOLAR at 60 L/min. Charge and mass profiles were determined. The surface potential of spacers followed the order of uncoated > detergent-coated > antistatic spacer. The spacers had minimal impact on the positively charged particles but the charge magnitude of the negatively charged particles was in the opposite order as the spacer surface potential. The charge-to-mass ratio of particles had little alteration for all measurements. Negatively charged particles had a higher tendency to deposit on the spacer walls, possibly due to their higher abundance in the confined spacer volume. The bipolar data may prove useful for designing better MDIs and spacers and modelling lung deposition of charged aerosol particles.

Inhalation therapy in patients with tracheostomy: a guide to clinicians

INTRODUCTION

Inhalation therapy has become a popular procedure for the treatment of patients with tracheostomy. However, clinicians are faced with many challenges during inhalation therapy because of the many factors affecting aerosol therapy to this patient population, and the lack of literature providing guidance in this area of research. Areas covered: The purpose of this paper is to describe the factors affecting aerosol drug delivery to patients with tracheostomy and to explain how to optimize inhalation therapy through device selection, interface selection and delivery technique in this patient population. Expert commentary: Many factors affect inhalation therapy in this patient population and without understanding the impact of these factors on aerosol drug delivery, clinicians will not be able to provide the treatment properly and patients may not benefit from prescribed medications. In the next 5 years, aerosol medicine will continue to experience tremendous growth with new devices and drug/device combinations. However, these advances will have minimal impact on inhalation therapy in patients with tracheostomy unless we provide guidance and training to clinicians on optimizing aerosol drug delivery to this patient population.

Drug Delivery in Asthmatic Children Following Coordinated and Uncoordinated Inhalation Maneuvers: A Randomized Crossover Trial

BACKGROUND

Valved holding chambers (VHCs) are used in children to deliver pressurized metered dose inhalers (pMDI). In vitro data suggest that uncoordinated use decreases the amount of drug available for inhalation. We hypothesize that in an ex vivo study, the coordinated maneuver will deliver more drug than the uncoordinated one.

PATIENTS AND METHODS

Thirty-two clinically stable asthmatic children, ages 5-8 years, completed the study. An aerosol filter was interposed between a small-volume nonelectrostatic VHC and a mouthpiece to capture the drug emitted by one puff of Flovent^® 220 mcg during tidal breathing. Inhalation and actuation parameters were measured by an electronic monitor, and the number of breaths required to empty the VHC was calculated. Subjects completed three coordinated and three uncoordinated (actuation at the beginning of inhalation and exhalation, respectively) runs in random order. Drug content from the filter and VHC was measured by high-performance liquid chromatography and expressed as percentage of emitted dose.

RESULTS

[mean (99% confidence interval)] Filter dose was higher during coordinated technique 46% (43%-50%) than during uncoordinated technique 41% (37%-44%) (p < 0.001). Peak inspiratory flow and tidal volume were 23.2 L/min (21.3-25.1 L/min) and 281 mL (251-311 mL), respectively. Subjects required three breaths to empty the VHC in 96% of the tests.

CONCLUSIONS

Actuating the pMDI into a small-volume nonelectrostatic VHC during exhalation reduced by 11% the amount of fluticasone captured at the exit of the VHC. Asthmatic children (5-8 years old) need three or less breaths to empty the small-volume VHC (NCT01714063).

Drug delivery interfaces: A way to optimize inhalation therapy in spontaneously breathing children

There are several different types of drug delivery interfaces available on the market. Using the right interface for aerosol drug delivery to children is essential for effective inhalation therapy. However, clinicians usually focus on selecting the right drug-device combination and often overlook the importance of interface selection that lead to suboptimal drug delivery and therapeutic response in neonates and pediatrics. Therefore, it is necessary to critically assess each interface and understand its advantage and disadvantages in aerosol drug delivery to this patient population. The purpose of this paper is to provide a critical assessment of drug delivery interfaces used for the treatment of children with pulmonary diseases by emphasizing advantages and problems associated with their use during inhalation therapy.

Pediatric in vitro and in silico models of deposition via oral and nasal inhalation

Respiratory tract deposition models provide a useful method for optimizing the design and administration of inhaled pharmaceutical aerosols, and can be useful for estimating exposure risks to inhaled particulate matter. As aerosol must first pass through the extrathoracic region prior to reaching the lungs, deposition in this region plays an important role in both cases. Compared to adults, much less extrathoracic deposition data are available with pediatric subjects. Recently, progress in magnetic resonance imaging and computed tomography scans to develop pediatric extrathoracic airway replicas has facilitated addressing this issue. Indeed, the use of realistic replicas for benchtop inhaler testing is now relatively common during the development and in vitro evaluation of pediatric respiratory drug delivery devices. Recently, in vitro empirical modeling studies using a moderate number of these realistic replicas have related airway geometry, particle size, fluid properties, and flow rate to extrathoracic deposition. Idealized geometries provide a standardized platform for inhaler testing and exposure risk assessment and have been designed to mimic average in vitro deposition in infants and children by replicating representative average geometrical dimensions. In silico mathematical models have used morphometric data and aerosol physics to illustrate the relative importance of different deposition mechanisms on respiratory tract deposition. Computational fluid dynamics simulations allow for the quantification of local deposition patterns and an in-depth examination of aerosol behavior in the respiratory tract. Recent studies have used both in vitro and in silico deposition measurements in realistic pediatric airway geometries to some success. This article reviews the current understanding of pediatric in vitro and in silico deposition modeling via oral and nasal inhalation.

Aerosol therapy in children: challenges and solutions

Using aerosolized medications for the treatment of children has gained importance over the years. However, aerosol drug delivery to infants and pediatrics is not an easy task as it has been influenced by many challenges. Most aerosol devices have been designed for use in adults not for children. Therefore, they require some critical assessment in device selection and often a level of adaptation for use with smaller children. It is well documented that each aerosol device and interface that have been used for the treatment of children has its own advantages and challenges in drug delivery. This paper provides a comprehensive review of dosing, drug-device combination, aerosol devices and interfaces used for drug delivery to children with pulmonary diseases. Solutions to the challenges with the aim of optimizing aerosol therapy in this patient population are also discussed.

The challenge of delivering therapeutic aerosols to asthma patients

The number of people with asthma continues to grow around the world, and asthma remains a poorly controlled disease despite the availability of management guidelines and highly effective medication. Patient noncompliance with therapy is a major reason for poor asthma control. Patients fail to comply with their asthma regimen for a wide variety of reasons, but incorrect use of inhaler devices is amongst the most common. The pressurised metered-dose inhaler (pMDI) is still the most frequently used device worldwide, but many patients fail to use it correctly, even after repeated tuition. Breath-actuated inhalers are easier to use than pMDIs. The rationale behind inhaler choice should be evidence based rather than empirical. When choosing an inhaler device, it is essential that it is easy to use correctly, dosing is consistent, adequate drug is deposited in both central and peripheral airways, and that drug deposition is independent of airflow. Regular checking of inhalation technique is crucial, as correct inhalation is one of the cornerstones of successful asthma management.

Electrostatics in pharmaceutical aerosols for inhalation

Electrostatics continues to play an important role in pharmaceutical aerosols for inhalation. Despite its ubiquitous nature, the charging process is complex and not well understood. Nonetheless, significant advances in the past few years continue to improve understanding and lead to better control of electrostatics. The purpose of this critical review is to present an overview of the literature, with an emphasis on how electrostatic charge can be useful in improving pulmonary drug delivery.

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.

Aerosol therapy for obstructive lung diseases: device selection and practice management issues

Inhaled aerosol therapies are the mainstay of treatment of obstructive lung diseases. Aerosol devices deliver drugs rapidly and directly into the airways, allowing high local drug concentrations while limiting systemic toxicity. While numerous clinical trials, literature reviews, and expert panel guidelines inform the choice of inhalational drugs, deciding which aerosol device (ie, metered-dose inhaler, nebulizer, or dry powder inhaler) best suits a given patient and clinical setting can seem arbitrary and confusing. Similar confusion regarding Current Procedural Terminology (CPT) coding for administration of aerosol therapies can lead to lost revenue from underbilling and wasted administrative effort handling denied claims. This article reviews the aerosol devices currently available, discusses their relative merits in various clinical settings, and summarizes appropriate CPT coding for aerosol therapy.

The Bioavailability of Salbutamol in Urine via Volumatic and Nonvolumatic Valved Holding Chambers

Purpose

Pressurized metered dose inhalers are commonly used in patients with asthma. However, the need to coordinate inhalation with inhaler actuation means that they are not suitable for use per se. Valved holding chamber devices were developed to overcome some of the problems of pressurized metered dose inhalers. Several types of holding chambers of different sizes are available in Iran. This study was designed to compare the effects of 2 commonly used valved holding chambers (Asthm Yar and Dam Yar) in Iran on bioavailability of salbutamol spray and also spirometric parameters in asthmatic patients.

Methods

This was a comparative experimental crossover study. Patients with mild to moderate asthma were entered in this study. Lung function was assessed using a portable spirometer (Spirolab, Progetti, Italy). Spirometric parameters of forced expiratory flow (FEF)_50%, FEF_25–75%, peak expiratory flow (PEF), forced expiratory volume in the first second of expiration (FEV₁), forced vital capacity (FVC), and FEV₁/FVC were measured. Urinary concentration of salbutamol as an index of pulmonary bioavailability was assayed with high-performance liquid chromatography.

Results

Forty patients (25 women and 15 men) with the mean age of 43.10 ± 12.99 years were studied. Mean ± SD changes of spirometric parameters before and after using Asthm Yar were not significantly different from those of Dam Yar. The relative bioavailability after inhalation with Asthm Yar was significantly higher than after inhalation with Dam Yar (P = 0.002).

Conclusions

Although the results indicate that relative bioavailability to the lung after inhalation with Asthm Yar was significantly higher than after inhalation with Dam Yar, its clinical importance should be tested.

Validation of methodology for recording breathing and simulating drug delivery through spacers and valved holding chambers

BACKGROUND

Output from spacers (or valved holding chambers) is sensitive to changes in breathing pattern. Different spacers have unique characteristics that may influence breathing. A method used for breathing simulation, where the simulated breathing can be recorded on subjects while they are using spacers, may allow for more accurate in vitro estimation of drug delivery in specific populations, using specific spacers.

METHODS

A flow chamber was used to record breathing while salbutamol was administered to two adult subjects through different spacers. Each subject performed a series of breathing patterns over a range of different inhalation volumes and flows. Salbutamol "inhaled" by subjects was captured on inspiratory filters and quantified by ultraviolet spectrophotometry. Recorded breathing patterns were simulated and ex vivo drug delivery was compared to in vitro drug delivery. Three equipment configurations were used to validate different aspects of the methodology. Configuration 1: breathing recorded by pneumotachometer placed directly between a human subject and the spacer. Breathing simulation performed with an identical setup. Configuration 2: spacer enclosed within a flow-chamber while breathing was recorded. Breathing simulation performed with an identical setup. Configuration 3: spacer enclosed in flow chamber to record breathing, but not when simulating breathing. In each configuration, the ex vivo and in vitro (simulated) filter doses were compared.

RESULTS

Configuration 1: the median difference between ex vivo and in vitro filter doses was 0.4% (range: -12.2 to 6.9%). Configuration 2: the median difference was -2.3% (range: -9.0 to 5.0%). Configuration 3: the median difference was 1.7% (range: -11.5 to 3.9%).

CONCLUSION

Our results indicate that in vitro simulated drug delivery using this method of recording using a flow chamber, closely approximates ex vivo total drug delivery. This technique allows for recording of breathing on patients while they are using spacers, with minimum increase in dead space or resistance, and no physical alteration in the patient-device interface.

Aerosol delivery to ventilated newborn infants: historical challenges and new directions

There are several aerosolized drugs which have been used in the treatment of neonatal respiratory illnesses, such as bronchodilators, diuretics, and surfactants. Preclinical in vitro and in vivo studies identified a number of variables that affect aerosol efficiency, including particle size, aerosol flows, nebulizer choice, and placement. Nevertheless, an optimized aerosol drug delivery system for mechanically ventilated infants still does not exist. Increasing interest in this form of drug delivery requires more controlled and focused research of drug/device combinations appropriate for the neonatal population. In the present article, we review the research that has been conducted thus far and discuss the next steps in developing the optimal aerosol delivery system for use in mechanically ventilated neonates.

Aerosol inhalation from spacers and valved holding chambers requires few tidal breaths for children

OBJECTIVE

The goal was to determine the number of breaths required to inhale salbutamol from different spacers/valved holding chambers (VHCs).

METHODS

Breathing patterns were recorded for 2- to 7-year-old children inhaling placebo from 4 different spacers/VHCs and were simulated by a flow generator. Drug delivery with different numbers of tidal breaths and with a single maximal breath was compared.

RESULTS

With tidal breathing, mean inhalation volumes were large, ranging from 384 mL to 445 mL. Mean values for drug delivery with an Aerochamber Plus (Trudell, London, Canada) were 40% (95% confidence interval [CI]: 34%-46%) and 41% (95% CI: 36%-47%) of the total dose with 2 and 9 tidal breaths, respectively. Mean drug delivery values with these breath numbers with a Funhaler (Visiomed, Perth, Australia) were 39% (95% CI: 34%-43%) and 38% (95% CI: 35%-42%), respectively. With a Volumatic (GlaxoSmithKline, Melbourne, Australia), mean drug delivery values with 2 and 9 tidal breaths were 37% (95% CI: 33%-41%) and 43% (95% CI: 40%-46%), respectively (P = .02); there was no significant difference in drug delivery with 3 versus 9 tidal breaths. With the modified soft drink bottle, drug delivery. Drug delivery was not improved with a single maximal breath with any device.

CONCLUSION

For young children, tidal breaths through a spacer/VHC were much larger than expected. Two tidal breaths were adequate for small-volume VHCs and a 500-mL modified soft drink bottle, and 3 tidal breaths were adequate for the larger Volumatic VHC.

Electrostatics of pharmaceutical inhalation aerosols

Objectives

This review focuses on the key findings and developments in the rapidly expanding research area of pharmaceutical aerosol electrostatics.

Key findings

Data from limited in-vivo and computational studies suggest that charges may potentially affect particle deposition in the airways. Charging occurs naturally in the absence of electric fields through triboelectrification, that is contact or friction for solids and flowing or spraying for liquids. Thus, particles and droplets emitted from pulmonary drug delivery devices (dry powder inhalers, metered dose inhalers with or without spacers, and nebulisers) are inherently charged. Apparatus with various operation principles have been employed in the measurement of pharmaceutical charges. Aerosol charges are dependent on many physicochemical parameters, such as formulation composition, device construction, relative humidity and solid-state properties. In some devices, electrification has been purposefully applied to facilitate powder dispersion and liquid atomisation.

Summary

Currently, there are no regulatory requirements on characterising electrostatic properties of inhalation aerosols. As research in this area progresses, the new knowledge gained may become valuable for the development and regulation of inhalation aerosol products.

Physical characterization of component particles included in dry powder inhalers. II. Dynamic characteristics

Characteristics of particles included in dry powder inhalers is extended from our previous report (in this journal) to include properties related to their dynamic performance. The performance of dry powder aerosols for pulmonary delivery is known to depend on fluidization and dispersion which reflects particle interactions in static powder beds. Since the solid state, surface/interfacial chemistry and static bulk properties were assessed previously, it remains to describe dynamic performance with a view to interpreting the integrated database. These studies result in complex data matrices from which correlations between specific properties and performance may be deduced. Lactose particles were characterized in terms of their dynamic flow, powder and aerosol electrostatics, and aerodynamic performance with respect to albuterol aerosol dispersion. There were clear correlations between flow properties and aerosol dispersion that would allow selection of lactose particles for formulation. Moreover, these properties can be related to data reported earlier on the morphological and surface properties of the carrier lactose particles. The proposed series of analytical approaches to the evaluation of powders for inclusion in aerosol products has merit and may be the basis for screening and ultimately predicting particle performance with a view to formulation optimization.

Facemasks and aerosol delivery by metered dose inhaler-valved holding chamber in young children: a tight seal makes the difference

A facemask on a valved holding chamber (VHC) facilitates the inhalation of aerosols from metered dose inhalers (MDI) for young children. Only recently the facemask has been recognized as a vital part for efficient aerosol delivery. Several in vitro and in vivo studies show that a tight seal of the facemask is crucial for optimal aerosol deposition to the lungs. Even a small leak can reduce the dose delivered to the lungs considerably. However, a tight seal is difficult to obtain when a child is not cooperative. Depending on the design of the facemask, it is easier to obtain a good seal. Factors such as dead space, shape, and material should be considered when designing a facemask. However, when a child is upset and not cooperative during the administration, aerosol deposition will be minimal, even with the best-designed facemask.

An in vivo and in vitro comparison of inhaled steroid delivery via a novel vortex actuator and a conventional valved holding chamber

BACKGROUND

Valved holding chambers improve delivery of inhaled corticosteroids to the lung but are bulky in design. A novel compact vortex actuator device has therefore been developed.

OBJECTIVES

To compare the in vitro and in vivo performance of a novel compact vortex actuator (the Neohaler [NH]) vs a conventional small-volume valve holding chamber (the AeroChamber Plus [AP].

METHODS

Seventeen asthmatic patients completed the study per protocol, receiving 4 weeks each of 100 microg/d (50-microg formulation) or 400 microg/d (100-microg formulation) of hydrofluoroalkane beclomethasone dipropionate via the NH or AP devices in a randomized crossover, double-blind, double-dummy, placebo-controlled design. The doubling dilution (dd) shift in methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20% (primary outcome) was used to evaluate anti-inflammatory effects and adrenal function to measure systemic exposure. The fine particle (<4.7 tm) dose was evaluated using an Andersen Cascade Impactor.

RESULTS

A total of 100 microg of hydrofluoroalkane beclomethasone dipropionate via the NH and AP produced 0.95-dd (95% confidence interval [CI], 0.44-1.45; P = .006) and 0.45-dd (95% CI, -0.16 to 1.06; P = .83) improvements from baseline in methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20%, respectively, with no statistically significant difference between devices: 0.50 dd (95% CI, -0.25 to 1.24; P = .18). At 400 microg/d, 1.08-dd (95% CI, 0.49-1.67; P = .006) and 0.85-dd (95% CI, 0.32-1.39; P = .02) improvements were found for the NH and AP, respectively, with a 0.23-dd difference (95% CI, -0.28 to 0.74; P = .36) between devices. No adrenal suppression occurred with either device. The in vitro fine particle dose was 39.1 microg for the NH and 39.0 microg for the AP with the 100-microg formulation and 26.0 g and 25.2 microg, respectively, with the 50-microg formulation.

CONCLUSIONS

Delivering hydrofluoroalkane beclomethasone dipropionate via the NH and AP attenuates asthmatic airway inflammation to a comparable degree and produces a similar in vitro fine particle dose profile.

Paediatric pulmonary drug delivery: considerations in asthma treatment

Aerosol therapy, the preferred route of administration for glucocorticosteroids and short-acting beta(2)-adrenergic agonists in the treatment of paediatric asthma, may be given via nebulisers, metered-dose inhalers and dry powder inhalers. For glucocorticosteroids, therapy with aerosolised medication results in higher concentrations of drug at the target organ with minimal systemic side effects compared with oral treatments. The dose of drug that reaches the airways in children with asthma is dependent on both the delivery device and patient-related factors. Factors that affect aerosol drug delivery are reviewed briefly. Advantages and disadvantages of each device and device-specific factors that influence patient preferences are examined. Although age-based device recommendations have been made, the optimal choice for drug delivery is the one that the patient or caregiver prefers to use, can use correctly and is most likely to use consistently.

In VitroValidation of99mTc-HFA-FP Delivered via pMDI-Spacer

The purpose of the study was to label Flixotide (fluticasone propionate [FP] with HFA propellant), with technetium-99m and validate that (99m)Tc acts as a suitable marker for FP when delivered via pMDI-spacer. Sodium pertechnetate was mixed with 5 mL of butanone. (99m)Tc was extracted into butanone and transferred into an empty canister. The (99m)Tc lined canister was heated, and the butanone evaporated to dryness. A supercooled commercial Flixotide canister was decrimped, and the contents transferred to the (99m)Tc lined canister and recrimped. The particle size distribution of FP and (99m)Tc from 10 radiolabeled canisters was measured using an Anderson cascade impactor calibrated to 28.3 L/min, and compared to commercial FP. The drug (FP) content of each particle size fraction was measured using ultraviolet spectrophotometry and the (99m)Tc level in each fraction was measured using an ionization chamber. The percentage of particles in the fine particle fraction (<;4.7 microm) and the percentage of (99m)Tc from commercial and radiolabeled canisters were compared. The mean (SD) % FP in the fine particle fraction, before and after label was 43.2 (1.8) % and 43.9 (2.6) %, respectively. The mean (SD) % (99m)Tc in the fine particle fraction was 42.1 (5.1) %. The mean %FP exiting spacer at (<4.7 microm) before labeling was not significantly different from the mean % FP exiting spacer at (<4.7 microm) after labeling (p > 0.05). The mean % (99m)Tc attached to particles at (<4.7 microm) after radiolabeling was not significantly different from the mean % FP levels (p > 0.05). The validation in this study indicates that (99m)Tc can act as a suitable marker for HFAFP, delivered via pMDI-spacer.

Recent advances in aerosol therapy for children with asthma

Inhalational drug delivery is the primary mode of asthma therapy in children and is the main focus of this article. Pressurized metered dose inhalers (pMDIs) are now the method of choice in infants and children under 5 years old, when used in combination with an appropriate valved holding chamber or spacer. Spacers are particularly important for steroid inhalation to maximize lung deposition and minimize unwanted oropharyngeal deposition. Optimal inhalation technique with a pMDI-spacer in infants is to inhale the drug by breathing tidally through the spacer. Drug delivery to the lungs using pMDIs can vary greatly, depending on the formulation used and the age of the child. Dry powder inhalers (DPIs) are driven by the peak inspiratory flow of the patient and are usually not appropriate for children under 5 or 6 years of age. Nebulizers continue to play a role in the treatment of acute asthma where high doses of bronchodilator are required, though multiple doses via pMDI spacer may suffice. Important drug delivery issues specific to children include compliance, use of mask versus mouthpiece, lower tidal volumes and inspiratory flows, determination of appropriate dosages, and minimization of adverse local and systemic effects.

Aerosol delivery to young children by pMDI-spacer: is facemask design important?

This study aimed at identifying in a daily-life setting the influence of facemask design on drug delivery via a spacer to young children. In a 4-week randomized crossover study, 24 children (7-23-months old) with recurrent wheeze tested the AstraZeneca, Galemed, and Hans Rudolph facemask combined with the NebuChamber at home. Each mask was tested twice daily for seven consecutive days. Filters positioned between the NebuChamber and facemask trapped the budesonide aerosol (200 microg, Pulmicort). Parents were asked to score the child's degree of cooperation during administration on diary cards. The administration procedure was evaluated through video recordings. Mean filter dose (standard deviation (s.d.)), expressed as % of nominal dose, was 39% (14), 47% (12), and 42% (11) for the AstraZeneca, the Galemed and the Hans Rudolph mask, respectively. Irrespective of the degree of cooperation, the Galemed mask gave significantly higher mean filter doses than the other masks (level of significance) (p < 0.045). Median (range) within-subject dose variability, expressed, as coefficient of variation (CV), was 37% (19-255), 32% (9-114), and 30% (9-115) for the AstraZeneca mask, the Galemed mask and the Hans Rudolph mask, respectively, not significant. Dose variability increased with decreasing cooperation for all three masks (p = 0.007). Drug delivery to young children with recurrent wheeze by means of the NebuChamber can be enhanced using the Galemed facemask. Dose variability seems to be independent of facemask design but mainly depends on cooperation.

Aerosol profile extracted from spacers as a determinant of actual dose

PURPOSE

We propose a novel method to evaluate the efficacy of a pressurized metered dose inhaler (pMDI) in combination with a spacer, by not only considering the total dose extractable from the spacer but also the dependence of dose on the volume available for aerosol inhalation.

METHODS

We studied volume-dependence of aerosol concentration during extraction from two commonly used plastic spacers (150 ml AerochamberPlus; 750 ml Volumatic) after a single puff of a 100 microg salbutamol pMDI (HFA-Ventolin), using laser photometric measurements.

RESULTS

After a delay of is in each spacer, the aerosol peak dose for AerochamberPlus was 2-fold that for Volumatic (p < 0.001), with the peak appearing well within the first 0.5 L even for the largest spacer. The opposite dose relationship is reached when considering total cumulative dose, which was 2-fold higher for Volumatic than for AerochamberPlus (p < 0.001); >95% of total cumulative dose was extracted well within 3 L for the largest spacer. The 2-fold cumulative dose relationship was confirmed by chemical assay on an absolute filter [AerochamberPlus: 21.4+/-3.2 (SD) microg; Volumatic: 43.8+/-9.1 (SD) microg].

CONCLUSIONS

Actual aerosol dose available to patients during inhalation via spacers can only be done on the basis of a quantification of aerosol peak dose and cumulative dose as a function of extracted volume.

Propellant-driven metered-dose inhalers for pulmonary drug delivery

The current market for pulmonary drug delivery is at a bottleneck. The therapeutic advantages of inhalation aerosols, and the potential for the lungs as a route for systemically acting drugs, vaccines and gene therapeutic agents, have resulted in a rapid growth of the industry. Alongside this, the environment of inhaler design and formulation has changed markedly in recent years. Environmental concerns over propellants, the commercial success of dry powder inhalers, and the apparent lack of advancement of propellant-driven metered-dose inhalers (pMDIs) has led to a less clear future for these devices. This review critically assesses these pressures and also potential opportunities for the pMDI. It is proposed that the future role of pMDIs will be determined by several important forces that can be classified under 'technology development' or 'market climate' categories. Technology development forces will be strengthened by the ability of the industry to have a systematic understanding of mechanisms of spray formation, perform subsequent and continued device and formulation advances, and a focus on all patient groups: particularly paediatric and geriatric populations. The ability to succeed in these areas will be largely determined by the willingness to invest in fundamental research of pMDI technologies.

Emitted doses of salbutamol pressurized metered-dose inhaler from five different plastic spacer devices

In a recent clinical study we have demonstrated that the bronchodilator effect of 200 microg salbutamol (Ventoline) was spacer device-dependent in 100 tested asthmatic children, with the Babyhaler providing greater efficacy for improving peak expiratory flow rate compared to Aeroscopic, Nebuhaler, Aerochamber and Volumatic. The aim of this present study was to correlate our clinical results to in vitro determinations of the emitted dose (ED) of Ventoline administered via these five different plastic spacer devices. ED was determined from the mean of single doses collected in unit dose sampling tubes using a constant suction flow of 28.3 L/min. Three pressurized metered-dose inhalers and three sets of spacer devices were used to obtain a total of 30 measurements per group. Inter-group results were compared by RM-ANOVA or Student-Newman-Keuls method when indicated. Babyhaler delivered significantly (P < 0.05) more salbutamol than Nebuhaler, Aerochamber and Aeroscopic (mean +/- standard deviation: 63.6 +/- 2.9 microg/100 microg actuation for Babyhaler vs. 59.4 +/- 8.6 for Nebuhaler, 50.8 +/- 5.0 for Aerochamber and 47.5 + 2.5 for Aeroscopic). The ED from Volumatic (61.5 +/- 7.9 microg/100 microg actuation) was similar to that from the Babyhaler. The variability in the ED was greatest with the large volume spacers. Despite a greater ED from the Babyhaler, in vitro results do not fully explain the in vivo results. However, the previously described clinical improvement seen with the Babyhaler may be due to the quantitatively different aerosol production in a more 'useful' size range, as well as the different breathing patterns of the children tested. The results of this present study question the relevance of mouthpiece filter collection studies using a constant sampling in predicting clinical or physiological outcomes.

Effect of a facemask leak on aerosol delivery from a pMDI-spacer system

The objective of this investigation was to study the relation between size and position of a mask leak on spacer output and lung dose. An upper-airway model (SAINT model, Erasmus MC) was connected to a breathing simulator. Facemasks with leaks ranging between 0 and 1.5 cm(2) were examined. Leaks were located close to the nose or close to the chin. During simulated breathing, 200 microg budesonide (Pulmicort, AstraZeneca) was delivered to the model via NebuChamber (AstraZeneca) with facemask. Spacer output and lung dose were measured by placing a filter between spacer and facemask or between model and breathing simulator, respectively. Budesonide trapped on the filter was quantified by means of HPLC, and expressed as percentage of the nominal dose. Mean spacer output doses for the nose position were 50, 38, 28, 12, 10, 6, and 0%, and for the chin position were 50, 40, 31, 11, 9, 4, and 0% for leaks of 0, 0.05, 0.1, 0.16, 0.2, 0.3, and larger than 0.4 cm(2), respectively. Mean lung doses for the nose position were 10, 8, 6, 3, 3, 1, 0, 0, 0, and 0%, and for the chin position were 10, 9, 8, 6, 6, 5, 1, 1, 0, and 0% for leaks of 0, 0.05, 0.1, 0.16, 0.2, 0.3, 0.4, 0.5, 1, and 1.5 cm(2). Efficiency of a pMDI-spacer facemask strongly depends on the size of a facemask leak. Spacer output did not depend on the position of the leak. Lung dose was higher for leaks near the chin than for leaks near the nose.