Development of a dry powder insufflation device with application in in vitro cell-based assays in the context of respiratory delivery.

Research on pharmaceutical dry powders has been increasing worldwide, along with increased therapeutic strategies for an application through the pulmonary or the nasal routes. In vitro methodologies and tests that mimic the respiratory environment and the process of inhalation itself are, thus, essential. The literature frequently reports cell-based in vitro assays that involve testing the dry powders in suspension. This experimental setting is not adequate, as both the lung and the nasal cavity are devoid of abundant liquid. However, devices that permit powder insufflation over cells in culture are either scarce or technically complex and expensive, which is not feasible in early stages of research. In this context, this work proposes the development of a device that allows the delivery of dry powders onto cell surfaces, thus simulating inhalation more appropriately. Subsequently, a quartz crystal microbalance (QCM) was used to establish a technique enabling the determination of dry powder deposition profiles. Additionally, the determination of the viability of respiratory cells (A549) after the insufflation of a dry powder using the developed device was performed. In all, a prototype for dry powder insufflation was designed and developed, using 3D printing methods for its production. It allowed the homogenous dispersion of the insufflated powders over a petri dish and a QCM crystal, and a more detailed study on how dry powders disperse over the supports. The device, already protected by a patent, still requires further improvement, especially regarding the method for powder weighing and the efficiency of the insufflation process, which is being addressed. The impact of insufflation of air and of locust bean gum (LBG)-based microparticles revealed absence of cytotoxic effect, as cell viability roughly above 70 % was always determined.

Performance of Low Air Volume Dry Powder Inhalers (LV-DPI) when Aerosolizing Excipient Enhanced Growth (EEG) Surfactant Powder Formulations.

Efficient delivery of dry powder aerosols dispersed with low volumes of air is challenging. This study aims to develop an efficient dry powder inhaler (DPI) capable of delivering spray-dried Survanta-EEG powders (3-10 mg) with a low volume (3 mL) of dispersion air. A series of iterative design modifications were made to a base low air volume actuated DPI. The modifications included the replacement of the original capsule chamber with an integral dose containment chamber, alteration of the entrainment air flow path through the device (from single-sided (SS) to straight through (ST)), change in the number of air inlet holes (from one to three), varying the outlet delivery tube length (45, 55, and 90 mm) and internal diameter (0.60, 0.89, and 1.17 mm). The modified devices were evaluated by determining the influence of the modifications and powder fill mass on aerosol performance of spray-dried Survanta-EEG powders. The optimal DPI was also evaluated for its ability to aerosolize a micronized powder. The optimized dose containment unit DPI had a 0.21 mL powder chamber, ST airflow path, three-0.60 mm air inlet holes, and 90 mm outlet delivery tube with 0.89 mm internal diameter. The powder dispersion characteristics of the optimal device were independent of fill mass with good powder emptying in one 3 mL actuation. At 10 mg fill mass, this device had an emitted mass of 5.3 mg with an aerosol Dv50 of 2.7 µm. After three 3 mL actuations, >85% of the spray-dried powder was emitted from the device. The emitted mass of the optimal device with micronized albuterol sulfate was >72% of the nominal fill mass of 10 mg in one 3 mL actuation. Design optimization produced a DPI capable of efficient performance with a dispersion air volume of 3 mL to aerosolize Survanta-EEG powders.

A generic fluticasone propionate and salmeterol dry powder inhaler: Evidence of usability, function, and robustness.

Background: A generic combination of fluticasone propionate and salmeterol xinafoate inhalation powder in a premetered, multidose, nonreusable inhaler was recently approved. Objective: To assess the performance of the generic device. Methods: Findings from three studies with regard to device usability, function, and robustness were reviewed. Results: In a study to assess device function in patients and healthy volunteers, the generic device was successfully used by patients with asthma and chronic obstructive pulmonary disease who were either dry powder inhaler users or dry powder inhaler-naive, even though they were not trained beyond being provided the instructions for use. In a study to measure inhaled flow rates generated by patients and healthy volunteers, the generic device consistently simulated the delivery of a full dose of drug, even to patients with severe respiratory disease and reduced inspiratory flow rates. Although the generic device had a slightly higher airflow resistance, this study demonstrated that this difference did not result in any clinically meaningful differences in terms of drug delivery. Pressure drop, a key parameter that drives the fluidization and aerosolization of the powder dose, was found to be comparable between the devices. In an open-label study, the generic device met all U.S. Food and Drug Administration specifications for device robustness after 21.5 days of twice-daily dosing via oral inhalation among 111 participants with asthma or chronic obstructive pulmonary disease. All inhalers tested demonstrated conformity with a pharmacopeia with respect to key quality parameters (assay, delivered dose uniformity, aerodynamic size distribution). There was no evidence of chemical degradation of the active ingredients, nor of microbial or water ingress into the powder, as a result of inhaler use.

Combined in Vitro-in Silico Approach to Predict Deposition and Pharmacokinetics of Budesonide Dry Powder Inhalers.

PURPOSE: A combined in vitro - in silico methodology was designed to estimate pharmacokinetics of budesonide delivered via dry powder inhaler. METHODS: Particle size distributions from three budesonide DPIs, measured with a Next Generation Impactor and Alberta Idealized Throat, were input into a lung deposition model to predict regional deposition. Subsequent systemic exposure was estimated using a pharmacokinetic model that incorporated Nernst-Brunner dissolution in the conducting airways to predict the net influence of dissolution, mucociliary clearance, and absorption. RESULTS: DPIs demonstrated significant in vitro differences in deposition, resulting in large differences in simulated regional deposition in the central conducting airways and the alveolar region. Similar but low deposition in the small conducting airways was observed with each DPI. Pharmacokinetic predictions showed good agreement with in vivo data from the literature. Peak systemic concentration was tied primarily to the alveolar dose, while the area under the curve was more dependent on the total lung dose. Tracheobronchial deposition was poorly correlated with pharmacokinetic data. CONCLUSIONS: Combination of realistic in vitro experiments, lung deposition modeling, and pharmacokinetic modeling was shown to provide reasonable estimation of in vivo systemic exposure from DPIs. Such combined approaches are useful in the development of orally inhaled drug products.

Numerical Study on Particle Adhesion in Dry Powder Inhaler Device.

This study investigated the particle adhesion mechanism in a capsule of dry powder inhaler (DPI) based on a combined computational fluid dynamics and discrete element method (CFD-DEM) approach. In this study, the Johnson-Kendall-Roberts (JKR) theory was selected as the adhesion force model. The simulation results corroborated the experimental results-numerous particles remained on the outlet side of the capsule, while a few particles remained on the inlet side. In the computer simulation, the modeled particles were placed in a capsule. They were quickly dispersed to both sides of the capsule, by air fed from one side of the capsule, and delivered from the air inlet side to the outlet side of the capsule. It was confirmed that vortex flows were seen at the outlet side of the capsule, which, however, were not seen at the inlet side. Numerous collisions were observed at the outlet side, while very few collisions were observed at the inlet side. These results suggested that the vortex flows were crucial to reduce the amount of residual particles in the capsule. The original capsule was then modified to enhance the vortex flow in the area, where many particles were found remaining. The modified capsule reduced the number of residual particles compared to the original capsule. This investigation suggests that the CFD-DEM approach can be a great tool for understanding the particle adhesion mechanism and improving the delivery efficiency of DPIs.

Advancement of a Positive-Pressure Dry Powder Inhaler for Children: Use of a Vertical Aerosolization Chamber and Three-Dimensional Rod Array Interface.

PURPOSE: Available dry powder inhalers (DPIs) have very poor lung delivery efficiencies in children. The objective of this study was to advance and experimentally test a positive-pressure air-jet DPI for children based on the use of a vertical aerosolization chamber and new patient interfaces that contain a three-dimensional (3D) rod array structure. METHODS: Aerosolization performance of different air-jet DPI designs was first evaluated based on a 10 mg powder fill mass of a spray-dried excipient enhanced growth (EEG) formulation. Devices were actuated with positive pressure using flow rate (10-20 L/min) and inhaled volume (750 ml) conditions consistent with a 5-year-old child. Devices with best performance were connected to different mouthpiece designs to determine the effect on aerosolization and tested for aerosol penetration through a realistic pediatric in vitro mouth-throat model. RESULTS: Use of the new vertical aerosolization chamber resulted in high quality aerosol formation. Inclusion of a 3D rod array structure in the mouthpiece further reduced aerosol size by approximately 20% compared to conditions without a rod array, and effectively dissipated the turbulent jet leaving the device. Best case device and mouthpiece combinations produced < 2% mouth-throat depositional loss and > 70% lung delivery efficiency based on loaded dose. CONCLUSIONS: In conclusion, use of a 3D rod array in the MP of a positive-pressure air-jet DPI was found to reduce aerosol size by 20%, not significantly increase MP depositional loss, reduce mouth-throat deposition by 6.4-fold and enable lung delivery efficiency as high as 73.4% of loaded dose based on pediatric test conditions.

Assessment of nicotine release from nicotine-loaded chitosan nanoparticles dry powder inhaler formulations via locomotor activity of C57BL/6 mice.

PURPOSE: This study aimed to assess the activity of controlled release nicotine from dry powder inhaler formulation via locomotor activity of C57BL/6 mice. METHODS: To achieve this we built a nose-only inhalation device for pulmonary administration of nicotine to mice and determined the optimal operational parameters. We used the locomotor activity test to compare the effects of the inhaled nicotine hydrogen tartrate-loaded chitosan nanoparticles (NHT-CS) with NHT in C57BL/6 mice. The minimum inhaled dose of NHT-CS required to alter locomotor activity was compared with inhaled and subcutaneously (s.c) injected NHT. Finally, histological examination of lung tissues was performed to ensure inhalation of NHT-CS did not cause lung damage. RESULTS: We found a flow rate of 0.9 L/min and an exposure time of 5 min achieved optimal delivery of nicotine. A minimum of 0.88 mg inhaled of NHT-CS or 0.59 mg inhaled of NHT was required to alter locomotor activity similarly to injection of 0.5 mg/kg nicotine, suggesting the reformulation process did not alter the activity of NHT-CS. No differences between untreated and NHT-CS treated lung tissue upon histological examination were observed. CONCLUSIONS: The results indicated the inhaled NHT-CS is a viable preclinical option for developing novel inhalation formulations as a potential anti-smoking therapeutic.

First-time handling of different inhalers by chronic obstructive lung disease patients.

Background: There is a lack of guidance on inhaler device selection and how to individualize inhaler choice when prescribed for the first-time.Aim of the work: To compare different inhalers regarding ease of use and number of counseling attempts needed for correct handling in subjects with a first experience to such inhalers; also, to investigate if there is a correlation between total correct steps achievements and patient demographics/clinical variables.Method: An open-label, non-drug interventional, cross-over study was conducted including 180 Egyptian patients with chronic obstructive pulmonary disease (COPD). The study evaluated handling of the most common inhalers in subjects with a first experience with them before hospital discharge. Subjects were randomized to handle 10 placebo inhalers including: [metered dose inhaler (pMDI), Aerolizer, Handihaler, Turbohaler, Diskus, Breezhaler, Ellipta, Easyhaler, Diskhaler, and Respimat] without receiving verbal or demonstrative instruction with allowable access to the patient information leaflets in native language supported by figures with enough time to read (baseline assessment). Subjects were then crossed-over to other inhalers with a first experience randomly. Inhalers with a reported past-experience were excluded. Inhaler-technique was assessed by using previously defined checklists, including essential steps and critical errors. The whole handling of the inhaler was demonstrated and the number of counseling attempts needed to correct handling was recorded. Patient demographics and clinical variables were recorded and correlated with correct handling steps.Results: The baseline percentages of total correct steps achievements as mean ± SD were 50 ± 19, 52 ± 16, 58 ± 14, 60 ± 17, 64 ± 10, 67 ± 16, 72 ± 17, 73 ± 11, 77 ± 14 and 86 ± 11% for Respimat, pMDI, Diskhaler, Diskus, Aerolizer, Handihaler, Easyhaler, Turbohaler, Breezhaler, and Ellipta respectively with p < 0.001. Baseline percentages of participants with at least 1 critical error significantly differed between inhalers (p < 0.05) with Ellipta showing the lowest percentage (37%). pMDI, Diskhaler, and Respimat showed the highest percentages (100%, 97% and 94% respectively). The number of counseling attempts needed to reach correct handling showed a significant difference among inhalers (p < 0.05). Ellipta showed the highest percentage of participants with correct handling with no counseling (20%) and the highest percentage of participants achieved with one counseling attempt (78%). Diskhaler, pMDI, and Respimat were the only inhalers included in a fourth counseling attempt (15%, 9%, and 6% respectively). Weak and very weak correlations were found between patient demographics/clinical variables and percentages of total correct steps achievements.Conclusion: Inhalers techniques greatly vary in their ease of use (self-explaining) ranging from easy inhalers (Ellipta) to intermediate inhalers (breezhaler, Easyhaler, Turbohaler, Aerolizer, Handihaler, and Diskus) followed by the most difficult inhalers (pMDI, Diskhaler, and Respimat). That must be considered when prescribing inhalers for the first time; choice of the inhaler should, in part, be based on ease of use and to be accompanied by repeated counseling.

Development of Dry Powder Inhaler Patient Interfaces for Improved Aerosol Delivery to Children.

The objective of this study was to explore different internal flow passages in the patient interface region of a new air-jet-based dry powder inhaler (DPI) in order to minimize device and extrathoracic aerosol depositional losses using computational fluid dynamics (CFD) simulations. The best-performing flow passages were used for oral and nose-to-lung (N2L) aerosol delivery in pediatric extrathoracic airway geometries consistent with a 5-year-old child. Aerosol delivery conditions were based on a previously developed and tested air-jet DPI device and included a base flow rate of 13.3 LPM (delivered from a small ventilation bag) and an inhaled air volume of 750 mL. Initial CFD models of the system clearly established that deposition on either the back of the throat or nasal cannula bifurcation was strongly correlated with the maximum velocity exiting the flow passage. Of all designs tested, the combination of a 3D rod array and rapid expansion of the flow passage side walls was found to dramatically reduce interface and device deposition and improve lung delivery of the aerosol. For oral aerosol administration, the optimal flow passage compared with a base case reduced device, mouthpiece, and mouth-throat deposition efficiencies by factors of 8-, 3-, and 2-fold, respectively. For N2L aerosol administration, the optimal flow pathway compared with a base case reduced device, nasal cannula, and nose-throat deposition by 16-, 6-, and 1.3-fold, respectively. In conclusion, a new patient interface design including a 3D rod array and rapid expansion dramatically improved transmission efficiency of a dry powder aerosol.

Prevalence and predictors of suboptimal peak inspiratory flow rate in COPD patients.

The aim of this study was to determine prevalence and possible clinical predictors of suboptimal peak inspiratory flow rate (PIFR) with different dry powder inhalers. PIFR was measured across all resistance ranges of In-Check Dial® in 180 chronic obstructive pulmonary disease (COPD) subjects before hospital discharge. COPD subjects were defined as suboptimal if measured PIFR was suboptimal with any resistance representative of specific inhalers (R1-R5). Demographics and clinical data were collected, including COPD Assessment Test (CAT) and modified Medical Research Council (mMRC) scores, Global Initiative for Obstructive Lung Disease (GOLD) stage spirometry by Spirodoc® and peak flow meter measurements with portable peak inspiratory and expiratory flow meters. All were correlated with In-Check Dial PIFRs. Suboptimal PIFR was 44.44% prevalent in COPD subjects. 55% of the suboptimal cohort was female which represent 57.14% of the total female population in the study. The distribution of suboptimal PIFR included 43.75% with R1, 67.5% with R2, 100% with R3, 13.75% with R4, and 21.25% with R5. In the suboptimal cohort, CAT score was significantly higher and spirometry demonstrated significantly lower lung function results compared to the optimal cohort (p < 0.05). The only parameter to show strong and moderate correlation with In-Check Dial PIFRs was PIFR measured by peak flow meter (p < 0.001). Suboptimal PIFR is common among COPD subjects at hospital discharge. Female gender and peak flow meter PIFR was the only predictor of suboptimal PIFR. Inhaler therapy for COPD patients must be personalized based on simple routine measurement of In-Check Dial PIFRs or peak flow meter PIFR to optimize clinical benefits .

Medication Tracking: Design and Fabrication of a Dry Powder Inhaler with Integrated Acoustic Element by 3D Printing.

PURPOSE: Asthma is a prevalent lung disorder that cause heavy burdens globally. Inhalation medicaments can relieve symptoms, improve lung function and, thus, the quality of life. However, it is well-documented that patients often do not get the prescribed dose out of an inhaler and the deposition of drug is suboptimal, due to incorrect handling of the device and wrong inhalation technique. This study aims to design and fabricate an acoustic dry powder inhaler (ADPI) for monitoring inhalation flow and related drug administration in order to evaluate whether the patient receives the complete dose out of the inhaler. METHODS: The devices were fabricated using 3D printing and the impact of the acoustic element geometry and printing resolution on the acoustic signal was investigated. Commercial Foradil (formoterol fumarate) capsules were used to validate the availability of the ADPI for medication dose tracking. The acoustic signal was analysed with Partial-Least-Squares (PLS) regression. RESULTS: Indicate that specific acoustic signals could be generated at different air flow rates using a passive acoustic element with specific design features. This acoustic signal could be correlated with the PLS model to the air flow rate. A more distinct sound spectra could be acquired at higher printing resolution. The sound spectra from the ADPI with no capsule, a full capsule and an empty capsule are different which could be used for medication tracking. CONCLUSIONS: This study shows that it is possible to evaluate the medication quality of inhaled medicaments by monitoring the acoustic signal generated during the inhalation process.

Prospective evAluatIon foR inhalation devices in Greek patients with COPD and asthma: The PAIR study.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) and asthma remain a major health burden. Adherence to inhaled therapy is critical in order to optimize treatment effectiveness. Properly designed questionnaires can assess patients' satisfaction with their inhaler devices. PATIENTS AND METHODS: A total of 766 patients with COPD, asthma or Asthma-COPD Overlap (ACO) were initially enrolled. During their first visit, patients were classified into three groups (Diskus™, Elpenhaler®, Turbuhaler®). Patients completed the FSI-10 questionnaire on Day 0 and Day 60. Test-retest reliability was evaluated. RESULTS: A total of 705 patients completed the study. FSI-10 questionnaire had good test-retest reliability (Total Intraclass Correlation Coefficient: 0.86). All dry powder inhaler (DPIs) yielded satisfactory results. Median score of FSI-10 questionnaire in first visit (FSI-10-I) was significantly higher for patients receiving Elpenhaler® (45, 95% CI: 44 to 46) than patients receiving Diskus™ (42, 95% CI: 41 to 43) and Turbuhaler® (42, 95% CI: 41 to 43) (p < 0.001). Accordingly, median score of FSI-10 questionnaire in the final visit (FSI-10-II) was significantly higher for patients receiving Elpenhaler® (46, 95% CI: 45 to 47) than patients receiving Diskus™ (42, 95% CI: 41 to 43) and Turbuhaler® (43, 95% CI: 42 to 44) (p < 0.001). CONCLUSION: FSI-10 questionnaire had good test-retest reliability and thus can be used in the follow-up of patients with COPD, asthma and ACO. All DPIs were highly acceptable among all study groups. Elpenhaler® achieved significantly higher ratings than Diskus™ and Turbuhaler® in FSI-10 score and presented higher preference among patients with obstructive lung diseases.

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.

Effect of Roughness on the Dispersion of Dry Powders for Inhalation: a Dynamic Visualization Perspective.

Dry powder inhalers have attracted more interest over the years in every aspect related to them. Interestingly, when focusing on the effects of particle morphology of the active or carrier (excipient), it is generally regarded particle size and shape to influence drug availability of aerosolized particles. However, to date, few studies have examined the effect of texture, i.e., roughness, on this relationship. The main objective of the present work is to gain a closer understanding of the influence of carrier morphology on the aerosolization performance of dry powder inhaler formulations. Image analysis and microscopy were used to visualize the aerosolization process. It is considered that the scale of morphological features on the surface of the carrier particles is responsible for the dispersion of the powder formulation, separation of the drug/carrier, and entrainment from a dry powder inhaler. Thus, for this study, the carrier particles of different surface roughness were mixed with micronized salbutamol sulphate. Aerosolization in vitro testing was used to evaluate the performance. The results indicate a connection between the qualitative surface roughness of coarse carriers and aerosolization performance during powder dispersibility. This investigation demonstrated that indeed, powder dispersion, a dynamic process, is influenced by the scale of the carrier morphology.

Establishment of relationships between native and inhalation device specific spirometric parameters as a step towards patient tailored inhalation device selection.

INTRODUCTION: Drug emission from DPIs is dependent on the inspiratory flow parameters through them, which are not directly measured by standard spirometry. Their estimation based on native spirometric data could help in choosing the appropriate device and optimizing the drug deposition. OBJECTIVES: The aim of this study was to survey patient preferences and to find correlations between breathing parameters of COPD patients through DPI devices and their baseline spirometric data, age, gender, disease severity and anthropometric characteristics. Another objective was to establish relationships between peak inspiratory flows (PIFdev) through Breezhaler®, Genuair® and Turbuhaler® inhalers and their determinants. METHODS: Breathing parameters of 49 patients with previously diagnosed COPD and currently using one of the above inhalers were recorded by normal spirometry and while inhaling through the selected DPIs. Statistical analysis of the measured data was completed. All specific data are provided as (mean ±â€¯standard deviation). RESULTS: More than 60% of the patients stated that their current device is the easiest to use. The means of the measured PIFdev values were 91.4 L/min, 77.1 L/min and 77.5 L/min for Breezhaler®, Genuair®, and Turbuhaler®, respectively. PIFdev values were significantly higher for males than for females, but differences upon age, BMI and disease severity group were not significant (at p = 0.05). Peak inspiratory flows through the inhalers (PIFdev) correlated best with their native spirometric counterparts (PIF) and linear PIFdev-PIF relationships could be determined (Breezhaler®: r = 0.60, p = 0.002, Genuair®: r = 0.55, p = 0.001, Turbuhaler®: r = 0.57, p = 0.002). Physical background of the deduced equations was also provided. CONCLUSIONS: Present correlations may be used to assess the success of inhalation of COPD patients through the studied devices and to choose the appropriate device for each patient. As a consequence, the amount of the drug emitted by the device can be optimized, the deposition efficiency within the lungs increased and the related therapeutic effect improved.

Determination of Passive Dry Powder Inhaler Aerodynamic Particle Size Distribution by Multi-Stage Cascade Impactor: International Pharmaceutical Aerosol Consortium on Regulation & Science (IPAC-RS) Recommendations to Support Both Product Quality Control and Clinical Programs.

The multi-stage cascade impactor (CI) is the mainstay method for the determination of the aerodynamic particle size distribution (APSD) of aerosols emitted from orally inhaled products (OIPs). CIs are designed to operate at a constant flow rate throughout the measurement process. However, it is necessary to mimic an inhalation maneuver to disperse the powder into an aerosol when testing passive dry powder inhalers (DPIs), which constitute a significant portion of available products in this inhaler class. Methods in the pharmacopeial compendia intended for product quality assurance initiate sampling by applying a vacuum to the measurement apparatus using a timer-operated solenoid valve located downstream of the CI, resulting in a period when the flow rate through the impactor rapidly increases from zero towards the target flow rate. This article provides recommendations for achieving consistent APSD measurements, including selection of the CI, pre-separator, and flow control equipment, as well as reviewing considerations that relate to the shape of the flow rate-sampling time profile. Evidence from comparisons of different DPIs delivering the same active pharmaceutical ingredients (APIs) is indicative that the compendial method for APSD measurement is insensitive as a predictor of pharmacokinetic outcomes. Although inappropriate for product quality testing, guidance is therefore provided towards adopting a more clinically realistic methodology, including the use of an anatomically appropriate inlet and mimicking patient inhalation at the DPI while operating the CI at constant flow rate. Many of these recommendations are applicable to the testing of other OIP classes.

Most frequent errors in inhalation technique of patients with asthma treated at a tertiary care hospital.

OBJECTIVE: To demonstrate the most frequent errors in inhalation technique in patients with asthma undergoing treatment at a tertiary care hospital. METHODS: A cross-sectional study with a convenience sample of asthma patients aged 18 years or over, treated at a pulmonology outpatient clinic of a tertiary care hospital. The assessment of inhalation technique of users of the dry powder inhalers Aerolizer®, Aerocaps and Diskus®, or metered-dose inhalers was based on the manufacturer's instructions for use of each inhaler device. Patients demonstrated the inhalation technique with empty inhaler devices, and it was considered correct when all stages were performed properly, or when errors probably did not interfere with the treatment outcome. RESULTS: Among 71 participants, 43 (60.5%) performed inhalation technique incorrectly. Among metered-dose inhalers and dry powder inhalers users, inhalation technique errors were found in 84.2% and 51.9%, respectively (p=0.013). Errors were more frequent at the exhalation stage (67.4%), followed by breathing in (58.1%) and apnea (51.2%). In the group using dry powder inhalers, the most common errors occurred during exhalation and, for those using metered-dose inhalers, the most compromised stage was aspiration. CONCLUSION: Errors were more frequent among those using metered-dose inhalers compared with dry powder inhalers. Misconceptions are more common at the expiration stage among users of dry powder inhalers and in aspiration among those on metered-dose inhalers.

Effect of USP Induction Ports, Glass Sampling Apparatus, and Inhaler Device Resistance on Aerodynamic Patterns of Fluticasone Propionate-Loaded Engineered Mannitol Microparticles.

The present investigation is to study the effect of two different induction ports (IP), i.e., USP IP and USP-modified IP equipped with andersen cascade impactor on in vitro aerodynamic performance along with the impact of USP-modified glass sampling apparatus on delivered dose uniformity of fluticasone propionate (FP) dry powder inhaler (DPI). FP DPI was fabricated by spray drying technique using engineered mannitol microparticles (EMP) with different force controlling agents, i.e., leucine and magnesium stearate. Additionally, commercially available two DPI inhaler devices namely Handihaler® and Breezhaler® were used to aerosolize the FP blends. Spherical smooth surface of EMP showed good powder flow properties and acceptable percentage content uniformity (> 95%). Amounts of FP deposited in cascade assembly using USP-modified IP with the Breezhaler® device was significantly higher (1.32-fold) as compared with the Handihaler® device. Moreover, USP-modified IP showed better deposition as compared with USP IP. Additionally, both inhaler devices showed a satisfactory delivered dose (> 105%) for FP using modified glass sampling apparatus at a flow rate of 60 L/min for 2 s. It was interesting to note that not only formulation properties but also IP geometry and device resistance have significant impact on DPI deposition pattern. This study is a first detailed account of aerodynamic performance of FP using USP-modified IP and USP-modified glass sampling apparatus. Thus, it can be of potential importance for both the academic and industry perspective.

Use of Computational Fluid Dynamics (CFD) Dispersion Parameters in the Development of a New DPI Actuated with Low Air Volumes.

PURPOSE: To determine the predictive power of computational fluid dynamics (CFD)-based dispersion parameters in the development of a new inline DPI that is actuated with low volumes of air. METHODS: Four new versions of a dose aerosolization and containment (DAC)-unit DPI were created with varying inlet and outlet orifice sizes and analyzed with results from five previous designs. A concurrent in vitro and CFD analysis was conducted to predict the emitted dose (ED; as a % of loaded dose) and aerosol mass median aerodynamic diameter (MMAD) produced by each device when actuated with 10 ml air bursts. CFD simulations of device operation were used to predict flow field and particle-based dispersion parameters. RESULTS: Comparisons of experimental and CFD results indicated that multiple flow field and particle-based dispersion parameters could be used to predict ED (minimum RMS Error = 4.9%) and MMAD (minimum RMS Error = 0.04 µm) to a high degree of accuracy. Based on experiments, the best overall device produced mean (standard deviation; SD) ED = 82.9(4.3)% and mean MMAD (SD) = 1.73(0.07)µm, which were in close agreement with the CFD predictions. CONCLUSIONS: A unique relationship was identified in the DAC-unit DPI in which reducing turbulence also reduced the MMAD.

Investigation of Electrostatic Behavior of Dry Powder-Inhaled Model Formulations.

The accumulation of electrostatic charge on drug particles and excipient powders arising from interparticulate collisions or contacts with other surfaces can lead to agglomeration and adhesion problems during the manufacturing process, filling, and delivery of dry powder inhaler (DPI) formulations. The objective of the study was to investigate the role of triboelectrification to better understand the influence of electrostatic charge on the performance of DPIs with 2 capsule-based dimensionally similar devices constructed with different materials. In addition, strategies to reduce electrostatic charge build up during the manufacturing process, and the processes involved in this phenomenon were investigated. Electrostatic charge measurements showed that there was a significant difference in electrostatic charge generated between tested formulations and devices. This affects particle detachment from carrier and thus significantly impacts aerosol performance. Conditioning fluticasone DPI capsules at defined temperature and humidity conditions reduced electrostatic charges acquired during manufacturing. Conditioning salmeterol DPI capsules at same conditions seemed disadvantageous for their aerosol performance because of increasing capillary forces and solid bridge formation caused by water absorption. Knowledge and understanding of the role of electrostatic forces in influencing DPI formulation performance was increased by these studies.