Difference in resistance to humidity between commonly used dry powder inhalers: an in vitro study

Ternary Dry Powder Agglomerate Inhalation Formulation of Melatonin With Air Jet Mixing to Improve In Vitro And In Vivo Performance

An improved agglomerate formulation with melatonin and fine lactose for dry powder inhalation using Turbuhaler® was developed. Co-grinding lactose with 1 % magnesium stearate prior to air jet mixing served as a key factor to improve the in vitro aerosolization and in vivo efficacy. Elevated mixing pressure facilitated the dispersion and homogenization of the cohesive mixture for even distribution of agglomerate size after spheroidization and subsequent higher emitted dose with lower variation. Magnesium stearate was employed as a tertiary component to adjust the interparticle force for better aerosolization. At optimized mixing pressure, co-grinding lactose with magnesium stearate before jet mixing displayed further improvement of fine particle fraction to 71.6 ± 3.1 %. The superior fine particle deposition efficiency contributed to rapid onset of action and a high bioavailability of 67.0 % after intratracheal administration to rats. Overall, an inhalable melatonin dry powder formulation exhibiting good aerosol property and lung deposition with clinical translation potential was developed.

Evaluating dry powder inhalers: From in vitro studies to mobile health technologies

Dry powder inhalers (DPIs) are essential in treating patients with pulmonary diseases. Since DPIs were introduced in the 1960s, a remarkable improvement has been made in their technology, dose delivery, efficiency, reproducibility, stability, and performance based on safety and efficacy. While there are many DPIs on the market and several more under development, it is vital to evaluate the performance of DPIs for effective aerosol drug delivery to patients with respiratory disorders. Their performance evaluation includes particle size, metering system, device design, dose preparation, inhalation technique, and patient-device integration. The purpose of this paper is to review current literature evaluating DPIs through in vitro studies, computational fluid models, and in vivo/clinical studies. We will also explain how mobile health applications are used to monitor and evaluate patients' adherence to prescribed medications.

Dry Powder Inhalation for Lung Delivery in Cystic Fibrosis

Pulmonary drug delivery has long been used for local and systemic administration of different medications used in acute and chronic respiratory diseases. Certain lung diseases, such as cystic fibrosis, rely heavily on chronic treatments, including targeted lung delivery. Pulmonary drug delivery possesses various physiological advantages compared to other delivery methods and is also convenient for the patient to use. However, the formulation of dry powder for pulmonary delivery proves challenging due to aerodynamic restrictions and the lower tolerance of the lung. The aim of this review is to provide an overview of the respiratory tract structure in patients with cystic fibrosis, including during acute and chronic lung infections and exacerbations. Furthermore, this review discusses the advantages of targeted lung delivery, including the physicochemical properties of dry powder and factors affecting clinical efficacy. Current inhalable drug treatments and drugs currently under development will also be discussed.

Impact of Solid-State Properties on the Aerosolization Performance of Spray-Dried Curcumin Powders

Amorphous and crystalline active pharmaceutical ingredients (APIs) are both widely studied for pulmonary delivery. The past research mainly studied the impact of solid-state properties on pharmacokinetic attributes; however, the influence of solid-state properties on aerosolization performance was much less studied. This study aimed to investigate the different aerosolization performances of amorphous and crystalline curcumin (Cur) stabilized with L-leucine. Cur was spray-dried with different concentrations of L-leucine (0, 5, 20, 35, and 50%, w/w) as both solution-based and suspension-based formulations to acquire amorphous and crystalline Cur powders. The physicochemical properties of the spray-dried powders, including particle size, morphology, and solid-state characteristics, were studied. The aerosolization performance as well as dissolution properties were evaluated. It was found that 35% (w/w) L-leucine or above led to the formation of amorphous Cur in the spray-dried powders, and the amorphous Cur powders exhibited higher FPF (70.8%, with 50% L-leucine, w/w) than the crystalline Cur formulations with an FPF at 56.3% (with 50% L-leucine, w/w). In conclusion, with a high concentration of L-leucine (35% or above) in the formulations, amorphous Cur would exhibit higher aerosolization efficiency than crystalline Cur. However, with a low concentration of L-leucine (20% or less) in the formulations, crystalline Cur would be preferred for more enhanced consideration.

Characterization of dry powder inhaler performance through experimental methods

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

In vitro-in vivo correlation of cascade impactor data for orally inhaled pharmaceutical aerosols

In vitro-in vivo correlation is the establishment of a predictive relationship between in vitro and in vivo data. In the context of cascade impactor results of orally inhaled pharmaceutical aerosols, this involves the linking of parameters such as the emitted dose, fine particle dose, fine particle fraction, and mass median aerodynamic diameter to in vivo lung deposition from scintigraphy data. If the dissolution and absorption processes after deposition are adequately understood, the correlation may be extended to the pharmacokinetics and pharmacodynamics of the delivered drugs. Correlation of impactor data to lung deposition is a relatively new research area that has been gaining recent interest. Although few in number, experiments and meta-analyses have been conducted to examine such correlations. An artificial neural network approach has also been employed to analyse the complex relationships between multiple factors and responses. However, much research is needed to generate more data to obtain robust correlations. These predictive models will be useful in improving the efficiency in product development by reducing the need of expensive and lengthy clinical trials.

Inhaler technique in asthma and COPD: challenges and unmet knowledge that can contribute to suboptimal use in real life

Introduction: Inhalers are the most commonly used devices for lung drug delivery in asthma and COPD. Inhaler use offers several advantages but requires the user's proper mastery. The issue of inhaler technique is very important as inhaler misuse remains common in real life regardless of the inhaler used and is associated with poor disease control.Areas covered:This narrative review analyses the key-steps of inhaler mastery and the significance of the errors of use for the main devices. There are uncertainties on many tasks of inhaler use and on those variations from recommended steps that are considered as critical errors.Expert opinion: Despite technological advancements, an easy-to-use device is not yet available. Whatever the chosen inhaler, health care givers' proper practical education with the opportunity of feedback learning has a key-role for improving inhaler technique, but is time-consuming, and remains limited to few successful experiences. Newer digital technologies will be applied to the field of inhaler education, but the lack of knowledge on many practical aspects of inhaler technique might be a limit for its extensive implementation. Possibly digital innovation might substantially contribute to reduce inhaler misuse only if clinicians, manufacturers, and subjects will cooperate together on this issue.

The Myth of Mild: Severe Exacerbations in Mild Asthma: An Underappreciated, but Preventable Problem

Asthma is a common, chronic inflammatory airway disease, characterised by unpredictable episodes of worsening symptoms, or exacerbations. Causes of asthma exacerbations include viral infections, exposure to allergen and air pollution, all of which increase the underlying inflammation that typifies asthma. Most (50-75%) patients are classed as having mild asthma, with symptoms that can be readily controlled with available inhaled medications. Paradoxically, for the past 30 years, the first treatment recommended in asthma management guidelines was short-acting β2-agonists (SABA), which not only have no anti-inflammatory properties but may, in fact, worsen inflammation. The Global Initiative for Asthma (GINA) 2019/2020 broke with this paradox by stating clearly that SABA should no longer be used alone as a reliever, for safety reasons. Instead, GINA now recommends an anti-inflammatory rescue/reliever approach for adult and adolescent patients, based on the combination of an inhaled corticosteroid with a rapid onset β2-agonist such as formoterol. This commentary highlights the fact that even patients with well-controlled mild asthma are at risk of severe, potentially life-threatening exacerbations, similar to those in patients with moderate or severe asthma, and therefore 'mild asthma', is a misnomer. The commentary describes the case history of a patient with mild asthma to illustrate how increasing use of SABA alone can worsen and prolong exacerbations when they occur. The author goes on to describe how the management of this patient's exacerbation could have been improved, and provides up-to-date advice on broader aspects of the management of mild asthma and exacerbations, supported by the recent changes to the GINA recommendations.

Bronchodilator Efficacy of a Single-Dose 12/400-µg Formoterol/Budesonide Combination as a Dry Powder for Inhalation Delivered by Discair® in Adult Patients with Moderate-to-Severe Stable COPD: Open-Label, Single-Arm, Phase IV Trial

BACKGROUND AND OBJECTIVES

A patient-friendly and easy-to-use multi-dose dry powder inhaler, Discair^®, has been recently developed. The objective of this study was to evaluate the bronchodilator efficacy of a single-dose 12/400-µg formoterol plus budesonide combination as a dry powder for inhalation delivered by Discair^® in adult patients with moderate-to-severe, stable, chronic obstructive pulmonary disease.

METHODS

A total of 33 male patients with moderate-to-severe, chronic obstructive pulmonary disease were included in this single-arm, open-label, phase IV trial. The primary efficacy parameters were the average maximum change in forced expiratory volume in 1 s (FEV₁, in L) and time to maximum FEV₁ response. Absolute and percent change from baseline in FEV₁ and forced vital capacity, maximum change and time to peak forced vital capacity response were also evaluated.

RESULTS

The mean post-bronchodilator FEV₁ maximum value was significantly higher than the pre-bronchodilator baseline FEV₁ value [1.66 (standard deviation 0.43) vs. 1.32 (standard deviation 0.35), p < 0.001], with an absolute change of 0.34 (standard deviation 0.18) and a percent change of 26.0 (standard deviation 0.14) from baseline to maximum response. The average time to peak FEV₁ response was 3.94 h (standard deviation 2.75), while the standardized area under the response-time curve from 0 to 12 h for FEV₁ was 2.72 (standard deviation 1.84). The FEV₁ and forced vital capacity values recorded at each time point during the 12-h post-bronchodilator period were also significantly higher than the baseline values (p < 0.001 for each).

CONCLUSIONS

Our findings revealed significant changes from baseline in post-bronchodilator peak and average FEV₁ and forced vital capacity responses, indicating bronchodilator efficacy of a single-dose 12/400 µg formoterol plus budesonide dry powder formulation delivered by Discair^® in patients with chronic obstructive pulmonary disease.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03028701.

Understanding Dry Powder Inhalers: Key Technical and Patient Preference Attributes

Inhalable medications for patients with asthma and chronic obstructive pulmonary disease (COPD) can be confusing even for health care professionals because of the multitude of available devices each with different operating principles. Dry powder inhalers (DPI) are a valuable option for almost all of the patients with asthma or COPD. Based on recorded patient inspiratory profiles, the peak inspiratory flow requirement of 30 L min⁻¹ of high-resistance devices does not usually pose any practical limitations for the patients. Suboptimal adherence and errors in device handling are common and require continuous checking and patient education in order to avoid these pitfalls of all inhalation therapy. The aim of this opinion paper is to describe the working principles of DPIs and to summarise their key properties in order to help prescribing the correct inhaler for each patient.

Funding: Orion Pharma.

Evaluation of patients' real-world post-dispensing use and storage environments of tiotropium bromide Respimat® soft mist inhaler on its in vitro dose delivery and lung deposition

BACKGROUND

Oral inhalation is the main drug delivery route for treating obstructive lung conditions. Thus, many inhaler devices with various design and pharmaceutical formulation have been introduced. The fine particle dose (FPD) and mass median aerodynamic diameter (MMAD ≤ 5 μm) of the aerosol delivered dose (DD) dictate the therapeutically effective peripheral lung deposition. This study evaluated the in vitro aerosol emission performance of tiotropium bromide emitted from Spiriva® Respimat® soft mist inhalers (R) after living under patients' real-world, post-dispensing handling environments.

METHODS

This was a two-stage investigation. In the first clinical stage, research ethical approval was obtained to enrol patients already been using R for at least 3 months. Those who signed consent were given both new R to use and temperature and relative humidity (RH) handheld, portable data loggers to keep in the vicinity of the given R. The participants returned the given R and data loggers after 2 weeks. Patient recruitment took place in Amman, Jordan, during the summer (RS) and winter (RW). Subsequently, in the second laboratory stage, other R were strictly stored at an average of 21.0 °C and 46.9% RH as control (RC). The Next Generation Impactor (NGI) was used to evaluate the RS, RW and RC. The NGI was operated at a flow rate of 30 L/min.

RESULTS

The RS were exposed to an average (range) 23.6 °C (18.2-37.5 °C) and 43.8% RH (21.4-60.0% RH) that were statistically comparable (p > 0.05) to that of the RW; 17.3 °C (13.2-26.7 °C) and 52.8% RH (26.3-69.1% RH). The RW and RC retention environments were statistically different (p < 0.05), whilst the RS and RC had comparable (p > 0.05) conditions. No significant differences (p > 0.05) were found in the tiotropium bromide DD (2.39 vs 2.43 μg), FPD (0.88 vs 0.90 μg) and MMAD (5.1 vs 4.98 μm) between the RS and RW, respectively. Compared to the RC inhalers, both the RS and RW devices had significantly higher FPD and relatively smaller tiotropium bromide particles.

CONCLUSIONS

Using the R under the fluctuating summer and winter environments of our patients would not affect its overall tiotropium bromide emission performance. The significant increase in the respirable mass of the RS and RW might be offset by the increase in particles <1 μm particularly in patients with poor inhaler technique.

Delivered Lung Dose and Aerodynamic Particle Size Distribution of Salbutamol Pressurized Metered Dose Inhaler After Living Under Patients' Realistic Retention Environments

Background: The impact of inhalers' postdispensing, real-life temperature and relative humidity (RH) environments on their delivered dose (DD) and aerodynamic particle size distribution (APSD) is usually overlooked. This work evaluated the salbutamol DD and APSD of Ventolin^® Evohaler^® (V) inhalers already been used and stored by respiratory patients. Methods: Adult patients, prescribed V for ≥3 months before study enrollment, were dispensed both new V to use and portable, handheld electronic temperature and RH data loggers to keep close to the given V before returning them both after 2-3 weeks. Patients' enrollment took place during summer (VS) and winter (VW) seasons. The returned V was then in vitro evaluated using the Next Generation Impactor, and compared with control V (VC) counterparts stored under 21°C and 46% RH. Results: The VS survived in fluctuating habitats of 21.2°C-40.4°C and 16.2%-63.2% RH, which significantly (p < 0.05) decreased the salbutamol DD from 80.4 to 70.5 μg compared with VC. This 12.3% DD reduction was accompanied with a decrease in the fine particle dose from 26.2 to 20.4 μg (p < 0.05), and an increase in the mass median aerodynamic diameter from 2.3 to 2.5 μm (p < 0.05). The VW and VC had equivalent DD and APSD. Conclusion: Patients using V are expected to receive smaller lung doses during the hot summer season compared with intentionally well-kept VC. To have equivalent lung deposition, V users should be advised to retain their inhalers around 20°C with minimal daily environmental fluctuations during summer times.

Differences in health care outcomes between postdischarge COPD patients treated with inhaled corticosteroid/long-acting β2-agonist via dry-powder inhalers and pressurized metered-dose inhalers

Purpose

The aim of this study was to examine real-world differences in health care resource use (HRU) and costs among COPD patients in the USA treated with a dry powder inhaler (DPI) or pressurized metered-dose inhaler (pMDI) following a COPD-related hospitalization.

Methods

This retrospective analysis used the Truven MarketScan^® databases. Eligibility criteria included 1) age ≥40 years, 2) COPD diagnosis, 3) inpatient admission with a diagnosis of COPD exacerbation, 4) inhaled corticosteroid (ICS)/long-acting β₂-agonist (LABA) prescription within 10 days of hospital discharge (index date), and 5) continuous enrollment for 12 months preindex and 90 days postindex. Outcomes included pre- and postindex HRU and costs. DPI and pMDI groups were compared on postindex outcomes via multivariate models controlling for demographic and baseline characteristics.

Results

The sample included 1,960 DPI and 1,086 pMDI ICS/LABA patients. During the preindex period, pMDI patients were significantly more likely to be prescribed a short-acting β-agonist, experienced more COPD exacerbation-related hospital days, and had a greater number of pulmonologist visits compared to DPI patients (P<0.05), all suggestive of greater disease severity. However, multivariate models revealed that pMDI patients incurred 10% lower all-cause postindex costs (predicted mean costs [2016 US dollars]: $2,673 vs $2,956) and 19% lower COPD-related costs (predicted mean costs: $138 vs $169; P<0.05). Additionally, pMDI patients were 28% less likely to experience a COPD exacerbation-related hospital readmission within 60 days postdischarge compared to the DPI patients (OR: 0.72, 95% CI: 0.52–0.99, P<0.05).

Conclusion

Despite greater COPD-related HRU and costs preceding index hospitalization, US patients using a pMDI after hospital discharge incurred significantly lower all-cause and COPD-related health care costs compared with those using a DPI, in addition to a decreased likelihood of a COPD exacerbation-related hospital readmission. Results suggest that inhaler device type may influence COPD outcomes and that COPD patients may derive greater clinical benefit from treatment delivered via pMDI vs DPI.

What to consider before prescribing inhaled medications: a pragmatic approach for evaluating the current inhaler landscape

Inhaled therapies are the cornerstone of treatment in asthma and chronic obstructive pulmonary disease, and there are a multitude of devices available. There is, however, a distinct lack of evidence-based guidance for healthcare providers on how to choose an appropriate inhaler. This review aims to summarise recent updates on topics related to inhaler choice, and to offer practical considerations for healthcare providers regarding currently marketed devices. The importance of choosing the right inhaler for the right patient is discussed, and the relative merits of dry powder inhalers, pressurised metered dose inhalers, breath-actuated pressurised metered dose inhalers, spacers and soft mist inhalers are considered. Compiling the latest studies in the devices therapy area, this review focuses on the most common types of handling errors, as well as the comparative rates of incorrect inhalation technique between devices. The impact of device-specific handling errors on inhaler performance is also discussed, and the characteristics that can impair optimal drug delivery, such as inhalation flow rate, inhalation volume and particle size, are compared between devices. The impact of patient perceptions, behaviours and problems with inhalation technique is analysed, and the need for appropriate patient education is also highlighted. The continued development of technology in inhaler design and the need to standardise study assessment, endpoints and patient populations are identified as future research needs. The reviews of this paper are available via the supplemental material section.

Fluticasone Propionate/Salmeterol MDPI (AirDuo RespiClick®): A Review in Asthma

The novel, easy-to-use, breath-actuated fluticasone propionate/salmeterol multidose dry powder inhaler (MDPI) (AirDuo RespiClick^®) was recently approved in the USA for twice-daily treatment of asthma in patients aged ≥ 12 years. This inhaled corticosteroid (ICS) and long-acting β₂-adrenoreceptor agonist (LABA) combination treatment is available in low-, mid- and high-dosage formulations (55/14, 113/14 and 232/14 μg, respectively). In 12-week, phase III trials in patients aged ≥ 12 years with persistent asthma, all three dosages of fluticasone propionate/salmeterol MDPI treatment produced significant improvements in lung function and other asthma symptoms compared with fluticasone propionate MDPI monotherapy or placebo MDPI. In a 26-week, phase III trial in this patient population, mid- and high-dosage fluticasone propionate/salmeterol MDPI were noninferior to mid- (250/50 μg) and high- (500/50 μg) dosage fluticasone propionate/salmeterol DPI (Advair Diskus^®), respectively, in terms of improvements in lung function. Treatment-emergent adverse events (TEAEs) with fluticasone propionate/salmeterol MDPI were mostly of mild to moderate severity, with no severe TEAEs deemed to be treatment related. Although long-term pharmacovigilance is required to fully establish its safety, given the ease of use and favorable characteristics of the device and its clinical efficacy at relatively low metered doses of the active moieties, fluticasone propionate/salmeterol MDPI is an important emerging treatment option in patients aged ≥ 12 years with asthma.

Dosing challenges in respiratory therapies

The pulmonary route of administration has been commonly used for local lung conditions such as asthma and chronic obstructive pulmonary disease (COPD). Recently, with the advent of new technologies available for both formulation and device design, molecules usually delivered at high doses, such as antibiotics and insulin to treat cystic fibrosis (CF) and diabetes, respectively, can now be delivered by inhalation as a dry powder. These molecules are generally delivered in milligrams instead of traditional microgram quantities. High dose delivery is most commonly achieved via dry powder inhalers (DPIs), breath activated devices designed with a formulated powder containing micronized drug with aerodynamic diameters between 1 and 5 µm. The powder formulation may also contain other excipients and/or carrier particles to improve the flowability and aerosol dispersion of the powder. A drawback with high doses is that the formulation contains a great number of fine particles, leading to a greater degree of cohesive forces, producing strongly bound agglomerates. With greater cohesive forces holding fine particles together, higher dispersion forces are needed for efficient de-agglomeration and aerosolisation. This requirement of greater dispersion forces has led to different dry powder formulations and vastly different inhaler designs. The purpose of this review is to evaluate the different formulation types, various DPI devices currently available, and how these affect the aerosolisation process and delivery of high dosed inhalable dry powder formulations to the lungs.

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.