Effect of add-on devices for aerosol drug delivery: deposition studies and clinical aspects

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

Salbutamol transport and deposition in healthy cat airways under different breathing conditions and particle sizes

Salbutamol is a bronchodilatator commonly used for the treatment of feline inflammatory lower airway disease, including asthma or acute bronchospasm. As in humans, a pressurized metered dose inhaler (pMDI) is used in conjunction with a spacer and a spherical mask to facilitate salbutamol administration. However, efficacy of inhalation therapy is influenced by different factors including the non-cooperative character of cats. In this study, the goal was to use computational fluid dynamics (CFD) to analyze the impact of breathing patterns and salbutamol particle size on overall drug transport and deposition using a specific spherical mask and spacer designed for cats. A model incorporating three-dimensional cat airway geometry, a commercially available spherical mask, and a 10 cm spacer, was used for CFD analysis. Two peak inspiratory flows were tested: 30 mL/s and 126 mL/s. Simulations were performed with 30s breathing different inspiratory and expiratory times, respiratory frequencies and peaks. Droplet spray transport and deposition were simulated with different particle sizes typical of the drug delivery therapies (1, 5, 10, and 15 μm). The percentage of particle deposition into the device and upper airways decreased with increasing particle diameter during both flows imposed in this cat model. During increased mean ventilatory rate (MVR) conditions, most of the salbutamol was lost in the upper airways. And during decreased MVR conditions, most of the particles remained in suspension (still in hold-up) between the mask and the carina, indicating the need for more than 30 s to be transported. In both flows the percentage of particles traveling to the lung was low at 1.5%-2.3%. In conclusion, in contrast to what has been described in the human literature, the results from this feline model suggest that the percentage of particles deposited on the upper airway decreases with increasing particle diameter.

Impact of different nebulisers' connections on aerosol therapy

BACKGROUND

Aerosol therapy has the advantage of a higher safety because of the local deposition of inhaled medication to the lung; however, the main drawback is the low and variable amount of delivered drug to patients. Hence, this study aimed to investigate the effect of different accessory connections on aerosol delivery from different nebulisers.

METHOD

This study consisted of 3 main models: in vitro, in vivo and ex vivo models. In vitro model, 6 nebulisers (3 Jet (Dolphin (2030 2001), Philips (SideStream) and Tylenol (TL009002)) and 3 vibrating mesh nebulisers (VMNs) (Aerogen Pro, Solo, an Nivo)) were charged with 5 mg/2 mL salbutamol and connected to 2 different connections (T-piece and Circulaire II Hybrid) with an inhalation filter attached to a breathing simulator. Inhaled amounts of drug (inhalation filter) and that remained inside nebuliser were measured. Concerning ex vivo and in vivo models, 24 subjects were involved in the study and they received 5 mg/2 mL salbutamol from 1 Jet nebuliser and 1 VMNs using both connections. Two urine samples were collected post 30 minutes and pooled 24 hours urine collection. For the ex vivo model, inhaled amounts of salbutamol were collected on filters placed between the subjects and the nebuliser.

RESULTS

Inhaled amounts of salbutamol expressed by the amount of drug detected on inhalation filters (for both in vitro and ex vivo) were significantly higher from both Jet and VMNs connected to the Circulaire II Hybrid connection than that released from nebulisers connected to T-piece. VMNs delivered a higher amount compared with jet nebulisers. The amount released from jet nebulizers were variables, unlike VMNs. Regarding in vivo results, amounts of drug detected in 30 minutes urine samples were consistent with in vitro and ex vivo models reflecting higher and significant amounts of drug delivered to the patient's lung for Circulaire II Hybrid connection compared with T-piece regarding both nebulisers.

CONCLUSION

Using a valved chamber with jet and VMNs significantly improved the inhaled amount of the emitted aerosol. VMNs were more effective than jet nebulisers with both connections.

Lung Deposition and Inspiratory Flow Rate in Patients with Chronic Obstructive Pulmonary Disease Using Different Inhalation Devices: A Systematic Literature Review and Expert Opinion

BACKGROUND

Our aim was to describe: 1) lung deposition and inspiratory flow rate; 2) main characteristics of inhaler devices in chronic obstructive pulmonary disease (COPD).

METHODS

A systematic literature review (SLR) was conducted to analyze the features and results of inhaler devices in COPD patients. These devices included pressurized metered-dose inhalers (pMDIs), dry powder inhalers (DPIs), and a soft mist inhaler (SMI). Inclusion and exclusion criteria were established, as well as search strategies (Medline, Embase, and the Cochrane Library up to April 2019). In vitro and in vivo studies were included. Two reviewers selected articles, collected and analyzed data independently. Narrative searches complemented the SLR. We discussed the results of the reviews in a nominal group meeting and agreed on various general principles and recommendations.

RESULTS

The SLR included 71 articles, some were of low-moderate quality, and there was great variability regarding populations and outcomes. Lung deposition rates varied across devices: 8%-53% for pMDIs, 7%-69% for DPIs, and 39%-67% for the SMI. The aerosol exit velocity was high with pMDIs (more than 3 m/s), while it is much slower (0.84-0.72 m/s) with the SMI. In general, pMDIs produce large-sized particles (1.22-8 μm), DPIs produce medium-sized particles (1.8-4.8 µm), and 60% of the particles reach an aerodynamic diameter <5 μm with the SMI. All inhalation devices reach central and peripheral lung regions, but the SMI distribution pattern might be better compared with pMDIs. DPIs' intrinsic resistance is higher than that of pMDIs and SMI, which are relatively similar and low. Depending on the DPI, the minimum flow inspiratory rate required was 30 L/min. pMDIs and SMI did not require a high inspiratory flow rate.

CONCLUSION

Lung deposition and inspiratory flow rate are key factors when selecting an inhalation device in COPD patients.

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.

An in vitro bioassay for evaluating the effect of inhaled bronchodilators on airway smooth muscle

PURPOSE

The development of inhaled drug products is expensive and involves time-consuming pharmacokinetic (PK) and pharmacodynamic (PD) studies. There are few in vitro cell-based assays to evaluate the disposition and action of orally inhaled drugs to guide early product development and minimise risk. The aim of the present study was to develop a co-culture bioassay, combining an airway epithelial cell line (Calu-3) with cultured human primary airway smooth muscle cells (ASM), integrated with apparatus to deliver pharmaceutical aerosols.

METHODS

An assay for measuring cyclic adenosine monophosphate (cAMP) in ASM derived from healthy donors was adapted to provide a biochemical surrogate for ASM relaxation. Concentration-response curves for cAMP were established for three drugs that elicit ASM relaxation: isoprenaline (ISO), forskolin (FOR) and salbutamol sulphate. The ASM bioassay was incorporated into a co-culture model in which air-interfaced Calu-3 cell layers, representing the permeability barrier of the airway epithelium, were grown on transwell inserts above ASM cells cultured in the well of the base-plate. The sensitivity of this bioassay to salbutamol delivered using different formulations and aerosol products was evaluated.

RESULTS

ASM responded with concentration dependent increases in cAMP when exposed to 10^-9 to 10^-5 M ISO, FOR or salbutamol sulphate solutions for 15 or 30 min. Salbutamol formulated with different counter ions elicited differential cAMP responses in ASM (xinafoate > base = sulphate) suggesting that this bioassay could discriminate between formulations with different potency. A similar rank order of potency was observed for the different salbutamol salts when applied as aerosols to the co-culture model.

DISCUSSION

We have developed a novel bioassay using human ASM in co-culture with human respiratory epithelial cells to better mimic various elements that contribute to the rate and extent of local drug availability in the lungs following topical administration. The bioassay offers an opportunity to investigate the factors determining the activity of inhaled bronchodilator drugs in a more biologically relevant system than that has previously been described and with further development and validation, this novel bioassay could provide a method to guide the more efficient development of inhaled bronchodilators, reducing the current reliance on in vivo studies.

Comparing the efficacy and safety of formoterol/budesonide pMDI versus its mono-components and other LABA/ICS in patients with asthma

INTRODUCTION

Pressurised metered dose inhalers (pMDIs) are effective drug delivery devices prescribed in obstructive airway diseases due to their convenience, portability, ease of enabling multiple doses in a single formulation, and storage in any orientation. For the management of asthma, the fixed-dose combination of a long-acting β₂-agonist (LABA) and an inhaled corticosteroid (ICS) has been recommended by Global Initiative for Asthma guideline as a preferred treatment option for patients who are uncontrolled with only ICS doses. One of the available LABA/ICS combinations is the formoterol/budesonide (FB).

AREAS COVERED

This article systematically reviews the efficacy and safety of the FB pMDI compared with the FB dry powder inhaler (DPI), individual mono-components (formoterol and budesonide) or salmeterol/fluticasone (SF) combination in the treatment of asthma among paediatric and adult patients. PubMed was searched with the string: ''((Budesonide) AND Formoterol) AND ((((pMDI) OR MDI) OR Pressurised Metered-dose inhaler) OR Metered-dose inhaler)'', in ALL fields. Screening of all the articles was done till February 2020. We have included 24 articles from the total of 142 hits received.

CONCLUSIONS

The FB pMDI is efficacious for the long-term management of asthma in patients 6 years of age and above. It has been shown to improve lung function and asthma control, and to reduce daytime and night-time symptoms, the number of rescue medication doses and asthma exacerbations. It also showed rapid onset of bronchodilatory effect with a dose-response relationship that allows patients to utilise it as a Single Maintenance And Reliever Therapy (SMART) regimen.

Spacers and Valved Holding Chambers-The Risk of Switching to Different Chambers

Spacers are pressurized metered-dose inhaler (pMDI) accessory devices developed to reduce problems of poor inhaler technique with pMDIs. Spacers that feature a 1-way inspiratory valve are termed valved holding chambers (VHCs); they act as aerosol reservoirs, allowing the user to actuate the pMDI device and then inhale the medication in a 2-step process that helps users overcome challenges in coordinating pMDI actuation with inhalation. Both spacers and VHCs have been shown to increase fine particle delivery to the lungs, decrease oropharyngeal deposition, and reduce corticosteroid-related side effects such as throat irritation, dysphonia, and oral candidiasis commonly seen with the use of pMDIs alone. Spacers and VHCs are not all the same, and also are not interchangeable: the performance may vary according to their size, shape, material of manufacture and propensity to become electrostatically charged, their mode of interface with the patient, and the presence or otherwise of valves and feedback devices. Thus, pairing of a pMDI plus a spacer or a VHC should be considered as a unique delivery system. In this Rostrum we discuss the risk potential for a patient getting switched to a spacer or VHC that delivers a reduced dose medication.

Novel optimized biopolymer-based nanoparticles for nose-to-brain delivery in the treatment of depressive diseases

A valid option to bypass the obstacle represented by the blood–brain barrier (BBB) in brain delivery is the use of the unconventional intranasal route of administration. The treatment of depressive diseases, resulting from the depletion of a neurotransmitter in the inter-synaptic space, such as serotonin, is indirectly treated using molecules that can permeate the BBB unlike the latter. In the present article, a set of nanovectors were produced using a mucoadhesive biopolymer, i.e. alginate (Alg). Optimizing the reaction, polymeric nanoparticles having diameter of 30–70 nm were produced, and water stable multi-walled carbon nanotubes functionalized (MWCNT-COOH)/Alg complexes were obtained. These nanovectors were loaded with serotonin, evaluating drug loading/release. By means of Raman microscopy, the cellular internalization of the (MWCNT-COOH)/Alg complex was demonstrated. A complete biocompatibility on neuronal cells was proved for the whole set of nanovectors. Finally, a method of self-administration was tested, which involves the use of a household apparatus, such as an aerosol machine, observing a fine particulate, able to deliver the nanovectors through the nose.

A valid option to bypass the obstacle represented by the blood–brain barrier (BBB) in brain delivery is the use of the unconventional intranasal route of administration.

Effects of flow rate on transnasal pulmonary aerosol delivery of bronchodilators via high-flow nasal cannula for patients with COPD and asthma: protocol for a randomised controlled trial

INTRODUCTION

Both in vitro and in vivo radiolabelled studies on nebulisation via high-flow nasal cannula showed that inhaled dose decreases as the administered gas flow increases. In our previous in vitro study, we investigated the effects of the ratio of gas flow to subject's peak inspiratory flow (GF:IF) on the aerosol deposition, which increased as the GF:IF decreased, with an optimal GF:IF between 0.1 and 0.5 producing a stable 'lung' deposition in both quiet and distressed breathing. Thus, we aim to validate our in vitro findings in subjects with reversible airflow limitations by assessing their response to inhaled bronchodilator.

METHODS AND ANALYSIS

This is a single-centre, randomised controlled trial. Subjects with chronic obstructive pulmonary disease or asthma with positive response to 400μg albuterol via metered dose inhaler and valved holding chamber will be enrolled and consented. After a washout period (1-3 days), subjects will be randomly assigned to inhale albuterol with one of three gas flows: 50 L/min, GF:IF=1.0 and GF:IF=0.5. In each arm, subjects will inhale 2 mL saline, followed by escalating doubling doses (0.5, 1, 2 and 4 mg) of albuterol in a fill volume of 2 mL, delivered by a vibrating mesh nebuliser via heated nasal cannula set up at 37°C. An interval of 30 min between each dose of albuterol, with spirometry measured at baseline and after each inhalation. Titration will be terminated if forced expiratory volume in 1 s improvement is <5%, or adverse event is observed.

ETHICS AND DISSEMINATION

This trial has been approved by the Ethic Committee of People's Liberation Army General Hospital, Beijing, China (no. S2018-200-01). The results will be disseminated through peer-reviewed journals, national and international conferences.

TRIAL REGISTRATION NUMBER

NCT03739359; Pre-results.

Use of spacers for patients treated with pressurized metered dose inhalers: focus on the VENTOLIN™ Mini Spacer

INTRODUCTION

Spacers offer a multitude of benefits by reducing the requirement to coordinate inhalation with actuation and improving inhaler technique in patients using a pressurized metered dose inhaler (pMDI). Spacers improve drug targeting by retaining within the spacer large particles normally deposited in the oropharynx, and by creating a prolonged aerosol cloud of fine particles to give the user increased time to inhale after actuation. This is particularly important in young children and the elderly to effectively deliver medication to the airways.

AREAS COVERED

By investigating the history and features of spacers, we demonstrate that the advantages of using spacers far outweigh their limitations. We also discuss the optimal characteristics of spacers in terms of shape, volume, presence of valve and static charge, and present a detailed discussion of the VENTOLIN™ Mini Spacer.

EXPERT OPINION

Generally, the shape and size of spacers makes them inherently inconvenient. Consideration of human factors and modern design may make them more attractive to patients. However, the incentive to use spacers should be their ability to help patients correctly use inhaled medications delivered by pMDIs. Understanding of these principles through education is key to their acceptance by patients.

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.

Inhaled corticosteroids: Effects on growth and bone health

BACKGROUND

Both slowed growth in children and reduced bone mineral density (BMD) are systemic effects of corticosteroids, and there is concern about the degree to which these systemic effects affect growth and BMD.

OBJECTIVE

To engage in a data-driven discussion of the effects of inhaled corticosteroids (ICSs) on growth in children and BMD.

METHODS

Articles were selected based on their relevance to this review.

RESULTS

Studies of ICSs in children in which growth was a secondary outcome have revealed slowed growth associated with low doses of budesonide, fluticasone propionate, and beclomethasone dipropionate. In the study of budesonide, the effect was permanent, and in the study of fluticasone propionate, the effect was long-lasting, but it is unclear whether the effect was permanent. However, the results of studies in which growth was the primary outcome were mixed. Slowed growth was detected in a study of beclomethasone dipropionate; however, slowed growth was not detected in a study of ciclesonide or flunisolide. A decrease in BMD acquisition in children was associated with high doses but not low to medium doses of ICSs. In adults, there was a dose-related effect of ICSs on BMD. Both higher daily dose and larger cumulative dose were associated with increased bone density loss.

CONCLUSION

Because of the systemic effects on growth and bone health, children should be monitored for growth using stadiometry every 3 to 6 months and BMD should be monitored yearly in patients being treated with high doses of ICSs.

Home-made spacer as an auxiliary device in administration of beclomethasone via pressurized metered dose inhaler for asthma control. A randomized controlled pragmatic trial

BACKGROUND

Holding chambers or spacers can enhance the efficacy of pressurized metered dose inhalers (pMDI) in delivering inhaled medications, as they reduce the need for hand-breath coordination and improve lower airways deposition. Nevertheless, their cost can be high for patients in low-income countries.

OBJECTIVE

To compare asthma control achieved with beclomethasone-dipropionate administered through a hydrofluoroalkane-driven pMDI (BDp-pMDI) coupled to a home-made spacer (HmS) or to a valved commercial spacer (VCS) as auxiliary devices.

METHODS

Sixty-three patients with poorly controlled asthma that had a BDp-pMDI prescription were randomized to use the inhaler coupled to a HmS made of 500 ml plastic bottles (Group HmS, n = 32) or to a VCS (Group VCS, n = 31) for 60 days. All were given training sessions. Asthma control was assessed through the Asthma Control Test (ACT) and forced expiratory volume in the first second (FEV1), both measured before, and 30 and 60 days after treatment began.

RESULTS

Both groups showed significant improvement in ACT scores after 30 and 60 days compared to baseline values (an increase of 7 and 7.8 points for the HmS group and 5.9 and 7.0 points for the VCS group, respectively, p < 0.001). There was no statistically significant difference in ACT scores between groups at any observation time (P = 0.261). FEV1 showed the same behavior.

CONCLUSIONS

A similar level of asthma control was achieved with beclomethasone-dipropionate administered through a pMDI whether the inhaler was coupled to the HmS or VCS. These results are significant for asthma control planning strategies in low-income communities. (Trial Register Number: RBR-5x4dc9).

Measurement of the Raman spectra and hygroscopicity of four pharmaceutical aerosols as they travel from pressurised metered dose inhalers (pMDI) to a model lung

Particle inhalation is an effective and rapid delivery method for a variety of pharmaceuticals, particularly bronchodilation drugs used for treating asthma and COPD. Conditions of relative humidity and temperature inside the lungs are generally very different from the outside ambient air, with the lung typically being warmer and more humid. Changes in humidity, from inhaler to lung, can cause hygroscopic phase transitions and particle growth. Increasing particle size and mass can negatively affect particle deposition within the lung leading to inefficient treatment, while deliquescence prior to impaction is liable to accelerate drug uptake. To better understand the hygroscopic properties of four pharmaceutical aerosol particles; pharmaceutical particles from four commercially available pressurised metered dose inhalers (pMDIs) were stably captured in an optical trap, and their composition was examined online via Raman spectroscopy. Micron-sized particles of salbutamol sulfate, salmeterol xinafoate, fluticasone propionate and ciclesonide were levitated and examined over a range of relative humidity values inside a chamber designed to mimic conditions within the respiratory tract. The effect of temperature upon hygroscopicity was also investigated for salbutamol sulfate particles. Salbutamol sulfate was found to have significant hygroscopicity, salmeterol xinafoate showed some hygroscopic interactions, whilst fluticasone propionate and ciclesonide revealed no observable hygroscopicity. Thermodynamic and structural modelling is used to explain the observed experimental results.

The evolution of spacers and valved holding chambers

Spacers and valved holding chambers (VHCs) are pressurized metered dose inhaler (pMDI) accessory devices, designed to overcome problems that patients commonly experience when administering aerosol via a pMDI. Spacers were developed in direct response to patient-related issues with pMDI technique, particularly, poor coordination between actuation and inhalation, and local side-effects arising from oropharyngeal deposition. Current clinical guidelines indicate the need for widespread prescription and use of spacers, but, despite their apparent ubiquity, the devices themselves are, unfortunately, all too commonly "disused" by patients. An understanding of the background from which spacers developed, and the key factors influencing the optimization of the spacer and the later VHC, is crucial to developing an appreciation of the potential of these devices, both contemporary and future, for improving the delivery of pressurized aerosols to patients. This review, informed by a full patent search and an extensive scientific literature review, takes into account the clinical and laboratory evidence, commercial developments, and the sometimes serendipitous details of scientific anecdotes to form a comprehensive perspective on the evolution of spacers, from their origins, in the early days of the pMDI, up to the present day.

Potential of a cyclone prototype spacer to improve in vitro dry powder delivery

Purpose

Low inspiratory force in patients with lung disease is associated with poor deagglomeration and high throat deposition when using dry powder inhalers (DPIs). The potential of two reverse flow cyclone prototypes as spacers for commercial carrier-based DPIs was investigated.

Methods

Cyclohaler®, Accuhaler® and Easyhaler® were tested with and without the spacers between 30 and 60 Lmin⁻¹. Deposition of particles in the next generation impactor and within the devices was determined by high performance liquid chromatography.

Results

Reduced induction port deposition of the emitted particles from the cyclones was observed due to the high retention of the drug within the spacers (e.g. salbutamol sulphate (SS): 67.89 ± 6.51% at 30 Lmin⁻¹ in Cheng 1). Fine particle fractions of aerosol as emitted from the cyclones were substantially higher than the DPIs alone. Moreover, the aerodynamic diameters of particles emitted from the cyclones were halved compared to the DPIs alone (e.g. SS from the Cyclohaler® at 4 kPa: 1.08 ± 0.05 μm vs. 3.00 ± 0.12 μm, with and without Cheng 2, respectively) and unaltered with increased flow rates.

Conclusion

This work has shown the potential of employing a cyclone spacer for commercial carrier-based DPIs to improve inhaled drug delivery.

Comparing the efficacy and safety of salmeterol/fluticasone pMDI versus its mono-components, other LABA/ICS pMDIs and salmeterol/fluticasone Diskus in patients with asthma

INTRODUCTION

Pressurized metered dose inhalers (pMDIs) are evolving to be a very effective drug delivery option in patients with airway diseases. They offer comparable lung deposition and reduced oropharyngeal deposition similar with the dry powder inhalers. As recommended by the Global Initiative for Asthma guidelines, the ideal maintenance treatment for asthma is a combination of long acting β2-agonists (LABAs) and inhaled corticosteroids (ICSs). One of the available LABA/ICS combinations is the salmeterol/fluticasone propionate combination (SFC) and a plethora of evidence supports its clinical efficacy and safety.

AREAS COVERED

This article focuses on the SFC hydrofluroalkane pMDI and compares the efficacy and tolerability with salmeterol and fluticasone given individually, and with other fixed-dose combinations namely formoterol/fluticasone, formoterol/beclometasone and formoterol/mometasone furoate, all delivered via pMDI. Also discussed is the efficacy and tolerability of the SFC delivered via a pMDI, as compared to the SFC via Diskus.

EXPERT OPINION

pMDIs play an important role in inhalation therapy given the low price, low maintenance and convenience of use. LABA/ICS combinations are the preferred choice of medication for asthma treatment and will remain the mainstay for the decades to come. In our opinion, pMDI should be the choice of device to administer LABA/ICS maintenance therapy, as it is already being used by the patients for reliever therapy, which may eventually improve patient adherence and compliance.

Bronchodilation with mometasone furoate/formoterol fumarate administered by metered-dose inhaler with and without a spacer in children with persistent asthma

BACKGROUND

The bronchodilatory effect of mometasone furoate/formoterol fumarate (MF/F) administered by metered-dose inhaler (MDI) with or without a spacer has not been evaluated previously in children aged 5-11 years.

METHODS

This was a randomized, multicenter, placebo-controlled, single-dose, four-period crossover study. Children with persistent asthma aged 5-11 years participated in this study. Subjects used inhaled corticosteroids with/without long-acting beta-2 agonists for 12 weeks before enrollment and at screening had forced expiratory volume in 1 sec (FEV1 ) ≥70% predicted. Subjects received MF/F MDI 100/10 µg with/without spacer (AeroChamber Plus® with Flow-Vu® Anti-Static Valved Holding Chamber), F-Dry Powder Inhaler (F-DPI) 10 µg, and placebo MDI with/without spacer in separate treatment periods. The primary endpoint was FEV1 area under the curve from 0 to 12 hr (AUC0-12hr ) for the comparison of MF/F with spacer versus placebo. Secondary measurements included MF/F without spacer versus placebo, as well as MF/F with spacer versus MF/F without spacer, and F-DPI versus placebo. Analysis was performed with an analysis of covariance model for a crossover study.

RESULTS

Data from 87 subjects were analyzed. MF/F with spacer demonstrated a larger change in mean FEV1 AUC0-12hr versus placebo (115 vs. -9 mL), with a treatment difference of 124 mL (95% CI 94-154, P < 0.001). Similarly, MF/F without spacer versus placebo resulted in a 102 mL difference in mean-adjusted FEV1 AUC0-12hr (95% CI 73-131, P < 0.001), whereas the difference between MF/F with spacer versus MF/F without spacer was 22 mL (95% CI -8 to 52, P = 0.144). The difference between F-DPI versus placebo was 106 mL (95% CI 77-135, P < 0.001). No unexpected adverse events were observed.

CONCLUSIONS

In this trial, MF/F MDI 100/10 µg demonstrated significant bronchodilation in children aged 5-11 years regardless of the use of a spacer. No difference in bronchodilation was observed between MF/F MDI and F-DPI.

Dry-powder inhalers in acute asthma

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

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.

Spirometry with bronchodilator test: effect that the use of large-volume spacers with antistatic treatment has on test response

OBJECTIVE

To evaluate whether the use of inhaled albuterol via a metered-dose inhaler with a large-volume spacer with antistatic treatment modifies the bronchodilator test results when compared with the usual technique (no spacer).

METHODS

A prospective study involving 24 patients, 18-45 years of age, clinically suspected of having asthma, and under treatment at the Outpatient Pulmonary Clinic of the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. All of the patients underwent two bronchodilator tests: one with and one without the use of a large-volume spacer.

RESULTS

There was no significant difference in the variation of FEV1 prior to and after bronchodilator use between the two techniques (mean ΔFEV1 = 0.01 L; 95% CI: -0.05 to 0.06; p = 0.824). No statistically significant difference was found between the two techniques regarding the qualitative results on the bronchodilator test (p = 1.00). There was concordance between the techniques in terms of the bronchodilator test results (kappa coefficient = 0.909; p < 0.005).

CONCLUSIONS

According to the results of this study, the use of large-volume spacers does not significantly modify bronchodilator test results.

Response to albuterol MDI delivered through an anti-static chamber during nocturnal bronchospasm

BACKGROUND

Decreasing electrostatic charge on valved holding chambers increases the amount of drug delivered. However, there are no data demonstrating that this increases bronchodilatation.

OBJECTIVE

To investigate the influence of reducing electrostatic charge on the bronchodilator response to albuterol inhaler during nocturnal bronchospasm.

METHODS

This randomized double-blind, double-dummy crossover study included subjects, 18-40 years old, with nocturnal bronchospasm (20% overnight decrease in peak flow on 3 of 7 nights during run-in), FEV(1) 60-80% predicted during the day, and ≥ 12% increase after albuterol. Subjects slept in the clinical research center up to 3 nights for each treatment. FEV(1) and heart rate were measured upon awakening spontaneously or at 4:00 am, and 15 min after each dose of 1, 2, and 4 cumulative puffs of albuterol via metered-dose inhaler. The drug was administered through an anti-static valved holding chamber (AeroChamber Plus Z-Stat) or a conventional valved holding chamber containing a static charge (AeroChamber Plus).

RESULTS

Of 88 consented subjects, 11 were randomized and 7 completed the study. Most exclusions were due to lack of objective evidence of nocturnal bronchospasm. Upon awakening, FEV(1) was 44 ± 9% of predicted before the anti-static chamber and 48 ± 7% of predicted before the static chamber. The mean ± SD percent increase in FEV(1) after 1, 2, and 4 cumulative puffs using the anti-static versus the static chamber, respectively, were 52 ± 26% versus 30 ± 19%, 73 ± 28% versus 48 ± 26%, and 90 ± 34% versus 64 ± 35%. The point estimates for the differences (and 95% CIs) between the devices (anti-static vs static) were 21% (4-38%) (P = .03), 23% (6-41%) (P = .02), and 25% (7-42%) (P = .01) for 1, 2, and 4 cumulative puffs, respectively. There was no significant difference in heart rate between treatments.

CONCLUSIONS

Delivery of albuterol through an anti-static chamber provides a clinically relevant improvement in bronchodilator response during acute, reversible bronchospasm such as nocturnal bronchospasm.

Deposition, imaging, and clearance: what remains to be done?

Deposition and clearance studies are used during product development and in fundamental research. These studies mostly involve radionuclide imaging, but pharmacokinetic methods are also used to assess the amount of drug absorbed through the lungs, which is closely related to lung deposition. Radionuclide imaging may be two-dimensional (gamma scintigraphy or planar imaging), or three-dimensional (single photon emission computed tomography and positron emission tomography). In October 2009, a group of scientists met at the "Thousand Years of Pharmaceutical Aerosols" conference in Reykjavik, Iceland, to discuss future research in key areas of pulmonary drug delivery. This article reports the session on "Deposition, imaging and clearance." The objective was partly to review our current understanding, but more importantly to assess "what remains to be done?" A need to standardize methodology and provide a regulatory framework by which data from radionuclide imaging methods could be compared between centers and used in the drug approval process was recognized. There is also a requirement for novel radiolabeling methods that are more representative of production processes for dry powder inhalers and pressurized metered dose inhalers. A need was identified for studies to aid our understanding of the relationship between clinical effects and regional deposition patterns of inhaled drugs. A robust methodology to assess clearance from small conducting airways should be developed, as a potential biomarker for therapies in cystic fibrosis and other diseases. The mechanisms by which inhaled nanoparticles are removed from the lungs, and the factors on which their removal depends, require further investigation. Last, and by no means least, we need a better understanding of patient-related factors, including how to reduce the variability in pulmonary drug delivery, in order to improve the precision of deposition and clearance measurements.

Asthma in Nigeria: are the facilities and resources available to support internationally endorsed standards of care?

OBJECTIVE

The objective of this study was to assess the facilities and resources available to support internationally endorsed standards of asthma care at tertiary hospitals (University teaching, Federal Medical Centre and State specialist Hospitals) in Nigeria.

METHODS

This cross sectional study was conducted among 68 tertiary hospitals (TH) in Nigeria from June 2009 to December 2009. Structured standards of care questionnaires on asthma based on the Global initiative for asthma (GINA) guideline were completed by physician working in each of the TH.

RESULTS

Most TH lacked the services of respiratory physicians, internists, and pediatricians. Available basic infrastructures were asthma clinics (0%), clinic registers (20.6%), and hospital protocol (17.6%), doctor's attendance of asthma CME (8.8%) and nurse educator with a bias for asthma (14.7%). Thirty eight percent of TH had peak flow meter, 29.4% had spirometer, skin allergy test kits (15.6%), pulse oximeter (38.2%) while 17.6% had arterial blood gases analyser. Nebuliser and spacer were available in 41.2% and 20.6% of TH respectively. Oral short acting beta 2 agonist (SABA) was available in 79.4% of the hospitals, glucocorticosteroid (79.4%), theophyllines (76.5%), and SABA (metered-dose inhaler MDI: 76.5%, Nebules: 35.3%). Long acting beta 2 agonist (LABA) and steroid fixed dose combination inhaler (50%) was available in 50% of TH. Glucocorticosteroid nasal spray was available in 33.3% of TH and <10% reported the availability of anti-cholinergic and chromoglycate inhaler and oral leukotriene antagonist. Standard oxygen delivery system and self-educational support materials were available in 52.9% of TH.

CONCLUSION

The available facilities and human resources for asthma management in Nigerian tertiary hospitals were not enough to support the standard internationally endorsed for asthma care. Provisions of deficient infrastructures and continuous training of health care personnel in asthma management are imperative to enhance the quality of care.

Targeting drugs to the airways: The role of spacer devices

AIM

Spacer devices are inhalation aids of varying dimension and complexity, specifically designed to overcome problems with the use of pressurised metered dose inhalers (pMDIs). The aim of this review is to examine the current understanding about these inhalation devices and discuss their advantages and disadvantages.

METHODS

The pertinent literature concerning the characteristics and effects of spacers on delivery and lung deposition of inhaled medications, as well as their clinical efficacy in patients with reversible airway obstruction, is examined.

RESULTS

Spacers minimise problems of poor inhalation technique with pMDI, reduce oropharyngeal deposition and increase lung deposition. Spacers improve the clinical effect of inhaled medications, especially in patients unable to use a pMDI properly. Compared to both pMDIs and dry-powder inhalers, spacers may increase the response to beta-adrenergic bronchodilators, even in patients with correct inhalation technique. A pMDI plus spacer has proven to be viable lower cost alternative to the use of a nebuliser for delivering large bronchodilator doses in patients with severe acute asthma or chronic obstructive pulmonary disease. The use of large-volume spacers is recommended for delivering high doses of inhaled corticosteroids, and may permit a lower maintenance dose to be used.

CONCLUSION

pMDIs may be routinely fitted with a spacer, especially in situations where correct pMDI use is unlikely.

Risk of adverse gastrointestinal events from inhaled corticosteroids

STUDY OBJECTIVE

To determine whether patients prescribed inhaled corticosteroids are at risk for adverse gastrointestinal effects.

DESIGN

Retrospective cohort study.

SETTING

Urban health center with an academic affiliation.

PATIENTS

A total of 19,443 adults (mean age 31.8 yrs) with airways disease, defined as a diagnosis of asthma or chronic obstructive pulmonary disease, and who were prescribed both an inhaled corticosteroid and albuterol (7156 patients) or inhaled albuterol alone (12,287 patients) between November 1977 and February 2002.

MEASUREMENTS AND MAIN RESULTS

The frequency of adverse gastrointestinal events in the patients who used inhaled corticosteroids and albuterol was compared with that in the patients who used albuterol alone. Adverse gastrointestinal outcomes included events such as gastritis, ulcers, and bleeding. Cox proportional hazards models were used to determine the risk of adverse events, controlling for possible confounders such as alcohol use or nonsteroidal antiinflammatory drug use. Adverse gastrointestinal events were observed in 461 (6.4%) patients using inhaled corticosteroids and albuterol and in 302 (2.5%) patients using only albuterol. After controlling for potential confounders, patients who used inhaled corticosteroids and albuterol had an increased risk for adverse gastrointestinal events compared with patients who used only inhaled albuterol (hazard ratio [HR] 1.26, 95% confidence interval [CI] 1.02-1.56). A prescription for a spacer device reduced this risk among patients using an inhaled corticosteroid (HR 0.26, 95% CI 0.20-0.34).

CONCLUSION

Patients using inhaled corticosteroids appear to have a slight risk for adverse gastrointestinal events that is mitigated in patients who used a spacer device.

Aerosol delivery of ergotamine tartrate via a breath-synchronized plume-control inhaler in humans

OBJECTIVE

To compare systemic delivery of ergotamine tartrate (ET) via a breath-synchronized, plume-control inhaler (BSPCI) (Tempo ET) with a sublingual ergot preparation and a commercial inhaler.

METHODS

Study 1 determined plasma ET concentrations in seven healthy subjects after administration of ET by a 2 mg tablet (Lingraine) and a BSPCI delivering 258 microg of ET. Study 2 determined plasma ET concentrations in 16 healthy subjects after administration via an ET metered dose inhaler (ME) (Medihaler) delivering 2052 microg of ET and a BSPCI delivering 129 microg of ET. Gamma scintigraphy with (99m)Tc validation was used to quantify lung deposition.

RESULTS

For both studies, ET C(max) was higher with the BSPCI (study 1: sublingual ET 134 pg/mL at 37 min; BSPCI 3743 pg/mL at 3 min; study 2: metered-dose inhaler 1109 pg/mL at 4 min; BSPCI 1210 pg/mL at 2.5 min). Mean dose normalized AUC was several-fold higher with the BSPCI compared with sublingual ET and ME dosing. Lung deposition of ET with the BSPCI was 33.5, 8.9, 11.4, and 13.2% for whole, central, intermediate, and peripheral lung, respectively, with a 1.5 peripheral : central ratio.

CONCLUSION

Based on these open-label studies, the BSPCI allows rapid delivery of potentially therapeutic plasma concentrations of ET at approximately 1/15th the dose of comparators.

The rejuvenated pressurised metered dose inhaler

The pressurised metered-dose inhaler (pMDI) has now been available for 50 years. Once regarded as an inefficient and difficult-to-use device, the technology has evolved significantly over the last few years, particularly since the introduction of novel formulations containing hydrofluoroalkane (HFA) propellants. Many modern HFA pMDIs deposit drug more efficiently in the lungs, impact less forcefully on the back of the throat and feel less cold than their chlorofluorocarbon pMDI counterparts. An improved understanding of technical factors makes it possible to design HFA pMDIs to have specific spray properties, particularly in terms of fine particle dose and spray velocity. Device technology has also progressed with the introduction of compact and convenient breath-actuated, breath-coordinated and velocity-modifying devices, which help patients to achieve a reliable lung dose. Although it faces competition from dry powder inhalers and possibly from novel soft-mist inhalers containing liquid formulations, the rejuvenated HFA pMDI is a device with a significant future for asthma, chronic obstructive pulmonary disease and wider treatment indications.

Metered-dose inhalers: actuators old and new

The actuator has been the patient interface of the metered-dose inhaler for the past 50 years. The original 1956 design remains a significant influence upon today's actuators and, moreover, its distinct geometry is still recognisable on the market. The actuator has contributed to the metered-dose inhaler's success as a clinically effective and cost-effective device. This review focuses upon developments since the actuator's introduction as an integral part of the metered-dose inhaler and discusses key aspects of its design that influence lung deposition potential. The ability of the actuator to reduce unwanted oropharyngeal drug deposition, facilitate correct patient use and provide valuable patient feedback is highlighted.

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.

Overcoming gaps in the management of asthma in older patients: new insights

Asthma is under-recognised and undertreated in older populations. This is not surprising, given that one-third of older people experience significant breathlessness. The differential diagnosis commonly includes asthma, chronic obstructive pulmonary disease (COPD), heart failure, malignancy, aspiration and infections. Because symptoms and signs of several cardiorespiratory diseases are nonspecific in older people and diseases commonly co-exist, investigations are important. A simple strategy for the investigation of breathlessness in older people should include a full blood count, chest radiograph, ECG, peak flow diary and/or spirometry with reversibility as a minimum. If there are major abnormalities on the ECG, an echocardiogram should also be performed. Diurnal variability in peak flow readings >or=20% or >or=15% reversibility in forced expiratory volume in 1 second, spontaneously or with treatment, support a diagnosis of asthma. Distinguishing asthma from COPD is important to allow appropriate management of disease based on aetiology, accurate prediction of treatment response, correct prognosis and appropriate management of the chest condition and co-morbidities. The two conditions are usually readily differentiated by clinical features, particularly age at onset, variability of symptoms and nocturnal symptoms in asthma, supported by the results of reversibility testing. Full lung function tests may not necessarily help in differentiating the two entities, although gas transfer factor is characteristically reduced in COPD and usually normal or high in asthma. Methacholine challenge tests previously mainly used in research are now also used widely and safely to confirm asthma in clinical settings. Interest in exhaled nitric oxide as a biomarker of airways inflammation is increasing as a noninvasive tool in the diagnosis and monitoring of asthma. Regular inhaled corticosteroids (ICS) are the mainstay of treatment of asthma. Even in mild disease in older adults, regular preventive treatment should be considered, given the poor perception of bronchoconstriction by older asthmatic patients. If symptoms persist despite ICS, addition of long-acting beta(2)-adrenoceptor agonists (LABA) should be considered. Addition of LABA to ICS improves asthma control and allows reduction in ICS dose. However, older people have been grossly under-represented in trials of LABA, many trials having excluded those >or=65 years of age. On meta-analysis, beta(2)-adrenoceptor agonists (both short acting and long acting) are associated with increased cardiovascular mortality and morbidity in asthma and COPD. While the evidence for excess cardiovascular mortality is stronger for short-acting beta(2)-adrenoceptor agonists, it would be prudent to exercise particular care in using beta(2)-adrenoceptor agonists (long acting and short acting) in those at risk of adverse cardiovascular outcomes, including older people. Regular review of cardiovascular status (and monitoring of serum potassium concentration) in patients taking beta(2)-adrenoceptor agonists is crucial. The response to LABA should be carefully monitored and alternative 'add-on' therapy such as leukotriene receptor antagonists (LRA) should be considered. LRA have fewer adverse effects and in individual cases may be more effective and appropriate than LABA. Long-term trials evaluating beta(2)-adrenoceptor agonists and other bronchodilator strategies are needed particularly in the elderly and in patients with cardiovascular co-morbidities. There is no evidence that addition of anticholinergics improves control of asthma further, although the role of long-acting anticholinergics in the prevention of disease progression is currently being researched. Older patients need to be taught good inhaler technique to improve delivery of medications to lungs, minimise adverse effects and reduce the need for oral corticosteroids. Nurse-led education programmes that include a written asthma self-management plan have the potential to improve outcomes.

Clinical and functional responses to salbutamol inhaled via different devices in asthmatic patients with induced bronchoconstriction

AIMS

This study aimed at evaluating changes in airway patency, lung volumes and perception of breathing discomfort intensity following salbutamol administration via the Diskus dry-powder inhaler (DPI) or a pressurized metered-dose inhaler with the Volumatic valved holding chamber (pMDI + Volumatic) in asthmatic patients with methacholine-induced bronchoconstriction.

METHODS

On six different study days, 18 patients inhaled methacholine until forced expiratory volume in 1 s (FEV(1)) decreased by approximately 35% of baseline. Following placebo, 200 and 400 microg of salbutamol through the pMDI + Volumatic or the Diskus, changes in FEV(1), volume-adjusted mean forced expiratory flow from 25 to 75% of the forced vital capacity (isoFEF(25-75)), lung volumes and breathing discomfort intensity, assessed by visual analogue scale (VAS) score, were repeatedly measured over a 60-min observation period.

RESULTS

Induced bronchoconstriction was accompanied by obvious reductions in lung volumes and increases in VAS score. After salbutamol administration, FEV(1) and VAS score changes were similar in all experimental conditions. However, following 400 microg salbutamol via pMDI + Volumatic, isoFEF(25-75) values increased up to 4.48 l s(-1) (95% confidence interval 4.06, 4.90), a significantly (P < 0.01) higher value than those attained in all other experimental conditions. Independently of the salbutamol dose, lung volumes rose to significantly (P < 0.01) higher levels in pMDI + Volumatic than in Diskus trials. The low salbutamol dose via the pMDI + Volumatic and the high dose via the DPI increased isoFEF(25-75) and lung volumes to similar extents.

CONCLUSIONS

Salbutamol via the pMDI + Volumatic provides greater isoFEF(25-75) and lung volume increases in asthmatic patients with induced bronchoconstriction; salbutamol-induced changes in VAS scores poorly reflect those in small airway patency. The lack of differences in FEV(1) increases observed after 200 and 400 microg salbutamol may reflect attainment of the flat portion of the dose-response curve using either device.

Spacer devices for metered dose inhalers

Spacer devices are attachments to the mouthpieces of pressurised metered dose inhalers (pMDIs), and range from tube spacers with a volume of <50 mL to holding chambers with a volume of 750 mL. Compared with a pMDI alone, spacers minimise coordination difficulties, reduce oropharyngeal deposition and often increase lung deposition. Spacers may not improve the clinical effect in patients able to use a pMDI properly, but may allow maintenance dosages of bronchodilators and corticosteroids to be reduced. Correct use of spacer devices is important, especially achieving control over electrostatic charge accumulation on the walls of plastic devices. In patients with severe acute asthma or severe chronic obstructive pulmonary disease, a pMDI plus large volume spacer may be a viable alternative to a nebuliser for delivering large bronchodilator doses. Although the addition of a spacer to every pMDI would not be justified, the use of large volume spacers has been recommended for any inhaled asthma drug in young children, and as a means of reducing systemic bioavailability of inhaled corticosteroids in adults and children alike.

Deposition and effects of inhaled corticosteroids

Inhaled corticosteroids are now recommended as maintenance therapy for all but the mildest cases of asthma, and may be delivered by a variety of devices and formulations. Drug delivery may be assessed by both in vitro and in vivo methods. Although drug deposition in the lungs is expected to predict clinical response, this relationship is often masked by the flat nature of corticosteroid dose-response curves. The effects of inhaled corticosteroids depend not only upon the pharmacology of the drug being administered, but also upon its delivery system, with more efficient devices not only improving therapeutic effect but also potentially increasing systemic adverse effects. Modern delivery systems that enhance drug targeting to the lungs make it possible to use lower dosages of inhaled corticosteroid, such that the clinical response is maintained but systemic exposure reduced.

In vitro performance of two common valved holding chambers with a chlorofluorocarbon-free beclomethasone metered-dose inhaler

STUDY OBJECTIVE

To compare in vitro aerosol deposition from a beclomethasone dipropionate metered-dose inhaler (MDI) containing hydrofluoroalkane propellant with that of the MDI in combination with two common valved holding chambers (VHCs) to evaluate how these VHCs affect the respirable dose of beclomethasone dipropionate.

DESIGN

In vitro aerosol deposition study.

SETTING

University research center.

DEVICES

Beclomethasone dipropionate hydrofluoroalkane MDI alone, the MDI with OptiChamber VHC, and the MDI with AeroChamber-Plus VHC.

INTERVENTION

The respirable dose (1-5-microm aerosol particles) of beclomethasone dipropionate was determined by sampling 10 80-microg actuations from five runs with each configuration (MDI alone, MDI with OptiChamber, and MDI with AeroChamber-Plus), using a well-established in vitro cascade impactor method.

MEASUREMENTS AND MAIN RESULTS

Beclomethasone dipropionate aerosol was washed from the impactor with 50% methanol and quantified by means of high-performance liquid chromatography. Differences among outcomes were determined by using analysis of variance. Mean beclomethasone dipropionate respirable dose from AeroChamber-Plus (27.2 +/- 10.0 microg/actuation) was not significantly different (p>0.05) from that of the MDI alone (29.0 +/- 7.0 microg/actuation). OptiChamber respirable dose (12.8 +/- 6.0 microg/actuation) was less than half that produced by either the AeroChamber-Plus or the MDI alone (p=0.013).

CONCLUSIONS

The OptiChamber and AeroChamber-Plus VHCs do not demonstrate equivalent in vitro performance when used with a beclomethasone dipropionate MDI that contains hydrofluoroalkane propellant. The respirable dose of beclomethasone dipropionate aerosol from the hydrofluoroalkane MDI was decreased by only 6% when the MDI was mated to an AeroChamber-Plus VHC and by 56% when used with an OptiChamber VHC.

The inhalers of the future? A review of dry powder devices on the market today

International agreements to ban the use of environmentally damaging chlorofluorocarbons (CFCs) have signalled an end to the traditional CFC-propelled pressurised metered dose inhaler (pMDI) which has long been the mainstay of topical asthma therapy. The need for acceptable and cost-effective replacement inhalers, combined with opportunities to develop generic formulations of patent-expired drugs, has fueled a lively response from the pharmaceutical industry. Improvements in pMDI design and reformulation with propellants such as hydrofluoroalkanes may offer significant advantages over CFC-pMDIs and prolong the widespread use of pressurised drug delivery systems for many years to come. In the longer term, however, another likely candidate for success in providing economical, efficient and acceptable inhaled therapies is the breath-actuated, multiple-dose dry powder inhaler (DPI). This review concentrates on the multiple-dose DPIs available within Europe today.

Radionuclide imaging technologies and their use in evaluating asthma drug deposition in the lungs

Whole lung and regional lung deposition of inhaled asthma drugs in the lungs can be quantified using either two-dimensional or three-dimensional radionuclide imaging methods. The two-dimensional method of gamma scintigraphy has been the most widely used, and is currently considered the industry standard, but the three-dimensional methods (SPECT, single photon emission computed tomography; and PET, positron emission tomography) give superior regional lung deposition data and will undoubtedly be used more frequently in future. Recent developments in radionuclide imaging are described, including an improved algorithm for assessing regional lung deposition in gamma scintigraphy, and a patent-protected radiolabelling method (TechneCoat), applicable to both gamma scintigraphy and SPECT. Radionuclide imaging data on new inhaled asthma products provide a milestone assessment, and the data form a bridge between in vitro testing and a full clinical trials program, allowing the latter to be entered with increased confidence.

The influence of inhaler selection on efficacy of asthma therapies

Many different devices are available to aid inhalational drug delivery. Although each device is claimed to have advantages over its rivals, the evidence to support greater efficacy of a particular device is scanty. Most comparative studies are underpowered or flawed in their design. They may use inappropriate end-points, or involve healthy subjects, whose response may be very different from the patient with acute severe asthma. The dosage of drug used in a trial may be at the shallow part of the dose-response curve, masking differences in devices. Only in a few cases have clinical trials detected a significant difference between devices, and trials have rarely taken patient preference into account. The most efficacious device in practice is likely to be the one that the patient will use regularly and in accordance with a health care workers' recommendations.

Control of particle size by coagulation of novel condensation aerosols in reservoir chambers

The coagulation growth behavior of capillary aerosol generator (CAG) condensation aerosols was investigated in a series of reservoir chambers. Aerosols consisted of a condensed system of 0.7% w/w benzil (model drug) in propylene glycol (vehicle). These were generated into 250-, 500-, 1,000-, and 2,000-mL reservoirs in both flowing air-stream and static air experiments. Changes in drug and total aerosol particle size were measured by a MOUDI cascade impactor. In both series of experiments the CAG aerosols grew in size. Growth in flowing air-stream experiments was attributed to the amount of accumulation aerosols experienced in reservoirs during sampling and increased with increasing reservoir volume. Mean (SD) MMAD's for the total mass distribution measured for the 250- and 2,000-mL reservoirs were 0.70 (0.02) and 0.87 (0.03) microm, respectively. For the benzil mass distribution, they were 0.64 (0.02) and 0.87 (0.06) microm, respectively. Growth in static air experiments was dependent on the volume aerosol boluses were restricted to and increased with decreasing reservoir volume. Mean (SD) initial MMAD's for the benzil mass distribution for the 250- and 2,000-mL reservoirs were 1.44 (0.03) and 1.24 (0.08) microm, respectively. Holding aerosols for up to 60 sec further increased their size. Mean (SD) MMAD's for benzil after holding for 60 sec in these reservoirs were 2.28 (0.04) and 1.67 (0.09) microm, respectively. The coagulation behavior and therefore particle size of CAG aerosols may be modified and controlled by reservoir chambers for drug targeting within the respiratory tract.

Management of asthma in young children

Asthma and recurrent airway symptoms in a young child can result in significant morbidity and reduced quality of life. There is significant variability in asthma severity. Even for those who will "outgrow" asthma, regular problems can be minimized with appropriate pharmacotherapy, education, and environmental control. Success with primary prevention through environmental control for children at high risk for asthma has been limited. Avoidance of passive tobacco smoke exposure has primary and secondary prevention benefits. An inhaled short-acting bronchodilator should be available for use as needed. Patients with regular symptoms should receive maintenance anti-inflammatory medication. Add-on therapy can be considered for those with inadequate control on inhaled corticosteroid. Physicians should regularly review drug delivery technique and compliance and provide all patients with a written asthma action plan to guide symptom monitoring and medication use. Physicians should also establish a partnership with the child and family, providing self-management training to enhance skills and confidence.