The evolution of spacers and valved holding chambers

Optimal Inhalation Profile of Pressurized Metered Dry Powder Inhaler Using a Valved Holding Chamber: A Dynamic Analysis

Background: The combined use of a pressurized metered-dose inhaler and valved holding chamber (pMDI+VHC) is recommended to improve efficiency and safety; however, aerosol release is likely to vary with the inhalation maneuver. This in vitro study investigated the aerodynamic characteristics and aerosol release features of pMDI+VHC (Aerochamber, Trudell Medical International). Methods: The static and dynamic changes in the airway resistance (Raw) during inhalation (withdrawal) through pMDI+VHC were measured. Subsequently, the aerosol released from pMDI+VHC was measured using simplified laser photometry during withdrawal with either fast ramp-up then steady or slow ramp-up followed by gradual decrement at different intensities and times to peak flow (TPWF). Results: Raw increased linearly with changes in the withdrawal flow (WF) rate between 10 and 50 L/min. The slope was steep in the low WF range (<50 L/min) and became milder in the higher range. The aerosol mass tended to increase with an increase in the peak WF (PWF) of slow ramp-up profile. When three different WF increment slopes (TPWF: 0.4, 1.4, and 2.4 seconds) were compared, the released aerosol mass tended to decrease, and the aerosol release time was prolonged at longer TPWF. When the PWF was increased, the aerosol release time became shorter, and the withdrawn volume required for 95% aerosol release became larger; however, it did not exceed 0.4 L at suitable TPWF (0.4 seconds). Conclusion: Raw analysis suggests that inhalation at 30-50 L/min is suitable for pMDI+VHC in this setting. Rapid (TPWF, 0.4 seconds) inhalation, but not necessarily long (maximum 2.0 seconds) and deep (but larger than 0.55 L), is also recommended. Practically, direct inhalation to be weaker than usual breathing, as fast as possible, and far less than 2.0 seconds.

Enhancing Inhalation Drug Delivery: A Comparative Study and Design Optimization of a Novel Valved Holding Chamber

This paper presents an innovative approach to the design optimization of valved holding chambers (VHCs), crucial devices for aerosol drug delivery. We present the design of an optimal cylindrical VHC body and introduce a novel valve based on particle impaction theory. The research combines computational simulations and physical experiments to assess the performance of various VHCs, with a special focus on the deposition patterns of medication particles within these devices. The methodology incorporates both experimental and simulation approaches to validate the reliability of the simulation. Emphasis is placed on the deposition patterns observed on the VHC walls and the classification of fine and large particles for salbutamol sulfate particles. The study reveals the superior efficacy of our valve design in separating particles compared to commercially available VHCs. In standard conditions, our valve design allows over 95% of particles under 7 μm to pass through while effectively filtering those larger than 8 μm. The optimized body design accomplishes a 60% particle mass flow fraction at the outlet and an average particle size reduction of 58.5%. When compared numerically in terms of size reduction, the optimal design outperforms the two commercially available VHCs selected. This study provides valuable insights into the optimization of VHC design, offering significant potential for improved aerosol drug delivery. Our findings demonstrate a new path forward for future studies, aiming to further optimize the design and performance of VHCs for enhanced pulmonary drug delivery.

Dynamic Analysis of Aerosol Release from a Pressurized Metered Dose Inhaler Combined with a Valved Holding Chamber Using Simplified Laser Photometry

Background: A pressurized metered dose inhaler combined with a valved holding chamber (pMDI+VHC) is used to prevent upper airway complications and improve the efficiency of inhaled drug delivery; however, the aerodynamic behavior of the released particles has not been well investigated. This study aimed at clarifying the particle release profiles of a VHC using simplified laser photometry. Methods: An inhalation simulator comprised a computer-controlled pump and a valve system that withdrew aerosol from a pMDI+VHC using a jump-up flow profile. A red laser illuminated the particles leaving VHC and evaluated the intensity of the light reflected by the released particles. Results: The data suggested that the output (OPT) from the laser reflection system represented particle concentration rather than particle mass, and the latter was calculated as OPT × instantaneous withdrawn flow (WF). Summation of OPT hyperbolically decreased with flow increment, whereas summation of OPT × instantaneous flow was not influenced by WF strength. Particle release trajectories consisted of three phases, namely increment with a parabolic curve, flat, and decrement with exponential decay phases. The flat phase appeared exclusively at low-flow withdrawal. These particle release profiles suggest the importance of early phase inhalation. The hyperbolic relationship between WF and particle release time revealed the minimal required withdrawal time at an individual withdrawal strength. Conclusions: The particle release mass was calculated as laser photometric output × instantaneous flow. Simulation of the released particles suggested the importance of early phase inhalation and predicted the minimally required withdrawal time from a pMDI+VHC.

Assessing of low-tech solutions for aerosol delivery: Comparative performance study of manufactured versus homemade spacers

PURPOSE

This study aims to evaluate the performance of low-cost homemade spacers compared with manufactured valved holding chambers (VHCs) for fluticasone propionate delivery via a pMDI (pressurized Metered Dose Inhaler).

METHODS

The Total Emitted Dose (TED) and particle size distribution were measured for pMDI alone or connected to the different spacers, according to CAN/CSA-Z264.1-02 standard. Two types of low-cost alternative and manufactured spacers were investigated: 500 mL plastic bottle and 553 mL aluminium can; non-antistatic plastic VHCs and aluminium antistatic VHCs.

RESULTS

The TED of homemade plastic bottle vs plastic VHC were similar in the 20-23% range. In contrast, the TED of homemade aluminium can was higher compared to aluminium VHC (83% vs 68%). The Fine Particle Fraction (FPF) was similar for the two plastic-based spacers (in the 12.68-17.60% range), although it was greater for the aluminium can compared to aluminium VHC (51% vs 42%). However, all spacers have limited large particles fraction, mainly deposited in the oropharyngeal tract, potentially decreasing side effects.

CONCLUSION

We demonstrated that low-tech solutions as homemade spacers have at least similar performances to VHC medical devices composed of same material (aluminium or plastic). Thus, low-cost homemade spacers represent alternatives in case of emergency and without VHCs nearby.

Bacterial Contamination of Inhalation Chambers Used for Cats and Dogs with Chronic Airway Diseases

Inhalation chambers (ICs) are regularly used in veterinary medicine for the inhalative treatment of chronic respiratory diseases in dogs and cats. Since therapy is usually required lifelong and daily, devices are frequently in use. The aim of this study was to identify bacterial contamination of ICs used for cats and dogs in relation to the applied cleaning measures. Swabs from ICs of 66 cats and 19 dogs with chronic airway diseases were obtained using a standardized protocol and subsequently cultured. A questionnaire was completed by the pet owners regarding the history of their pet's illness and applied device cleaning measures. Overall, 64% (54/86) of the ICs were found to be contaminated; the mask was significantly (p < 0.001) more often contaminated than other device parts. Most cultured bacteria were environmental contaminants; however, some harbored pathogenic potential. Cleaning frequency and method did not significantly influence the presence of contamination. Bacterial contamination of ICs, used for cats and dogs, is common but is not significantly influenced by the type or frequency of cleaning. To avoid potential infection by opportunistic bacteria, the instruction of pet owners regarding the maintenance of the ICs is recommended.

An Investigation into the Factors Associated with Incorrect Use of a Pressurized Metered-Dose Inhaler in Japanese Patients

Rationale: Inhalation of the correct dose of a short-acting beta 2 agonist (SABA) from a pressurized metered-dose inhaler (pMDI) is essential for the relief of symptoms in patients with asthma and/or chronic obstructive pulmonary disease. The aim of this study was to evaluate the prevalence and factors associated with the incorrect use of a pMDI. Methods: This study retrospectively assessed the electronic medical records of 161 patients with various respiratory diseases. The patients had never used a pMDI and underwent training by pharmacists educated in the use of a pMDI followed by bronchodilator reversibility testing at our hospital. The patients' characteristics and various lung capacity parameters were evaluated for association with the incorrect use of a pMDI. Results: Thirty-nine of the 161 (24.2%) patients, including 46% of 28 patients older than 80 years, used the pMDI incorrectly, mainly because of incoordination between activation of the device and inhalation (n = 11), inadequate strength to manipulate the device (n = 9), too short duration of inhalation (n = 6), and difficulty in breath holding (n = 3). Advanced age; lower height; and decreased lung volumes, including vital capacity (VC), inspiratory capacity, inspiratory reserve volume (IRV), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow rate, were associated with the incorrect use of a pMDI. Neither the body weight, tidal volume, expiratory reserve volume, %FVC predicted, %FEV1 predicted, nor FEV1% was associated with the incorrect use of a pMDI. Multivariate binomial logistic regression analysis identified decreased IRV as the only independent predictor associated with the incorrect use of a pMDI. Conclusions: Physicians should be aware that elderly patients or patients with decreased IRV might be unable to obtain the correct SABA dose from a pMDI. A large-scale prospective study is required to confirm these findings from our retrospective study with a small group of patients.

[Inhalation therapy in dogs and cats with chronic lower airway disease - a literature review]

Chronic respiratory diseases are prevalent medical conditions in dogs and cats requiring lifelong treatment. Mainstay of therapy for chronic inflammatory respiratory diseases are glucocorticoids. Concurrent treatment with bronchodilators may be necessary to control clinical signs sufficiently. Due to the successful use in people as well as subsequent reduction of adverse effects of long-term glucocorticoid therapy, inhalative therapy has become increasingly important in veterinary medicine as well. Primarily spacers or valved holding chambers, in combination with metered dose inhalers, are used in dogs and cats. The technical properties of these devices, as well as their use and maintenance will be described in the following article. Furthermore, the existing literature regarding efficacy of inhalative medications for therapy of chronic inflammatory airway diseases in dogs and cats will be summarized.

The history, current state and perspectives of aerosol therapy

Nebulization is a very effective method of drug administration. This technique has been popular since ancient times when inhalation of plants rich in tropane alkaloids with spasmolytic and analgesic effects was widely used. Undoubtedly, the invention of anasthesia in the 19th century had an influence on the development of this technique. It resulted in the search for devices that facilitated anasthesia such as pulveriser or hydronium. From the second half of the 21st century, when the first DPI and MDI inhalers were launched, the constant development of aerosol therapy has been noticed. This is due to the fact that nebulization, compared with other means of medicinal substance application (such as oral and intravenous routes of administration), is safer and it exhibits a positive dose/efficacy ratio connected to the reduction of the dose. It enables drugs administration through the lung and possesses very fast onset action. Therefore, various drugs prescribed in respiratory diseases (such as corticosteroids, β-agonists, anticholinergics) are present on the market in a form of an aerosol.

Inhaled vaccine delivery in the combat against respiratory viruses: a 2021 overview of recent developments and implications for COVID-19

INTRODUCTION

As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care. Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses.

AREAS COVERED

Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy. We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible. The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar.

EXPERT OPINION

We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages. Firstly, their dry state can tremendously increase vaccine stability and shelf-life. Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns. Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.

Mask Use with Spacers/Valved Holding Chambers and Metered Dose Inhalers among Children with Asthma

Inhaler misuse is highly prevalent and associated with high morbidity and costs. For metered dose inhalers, proper use can be supported with devices such as spacers/valved holding chambers (VHCs) and masks to effectively deliver inhaled medication to the lungs. However, guidelines are vague about which children with asthma should use spacers/VHCs with masks to deliver medication from metered dose inhalers as well as when they should transition to spacers/VHCs with mouthpieces. In this paper, we provide a focused review of the evidence for mask use, highlighting unclear and conflicting information in guidelines and studies. We synthesize the differences in recommendations and practice. Based on these findings, we call for future research to determine the appropriate age and necessary skills for transitioning children from using metered dose inhalers with spacers/VHCs and masks to using spacers/VHCs and mouthpieces. Guidelines about mask use should be standardized to help ensure optimal medical delivery for patients, provide consistent inhaler prescriptions and education across settings, and support team-based care to help lower pediatric asthma morbidity and costs.

Effect of functional principle, delivery technique, and connection used on aerosol delivery from different nebulizers: An in-vitro study

OBJECTIVE

Nebulizers can be divided according to their functional principle into jet, ultrasonic and vibrating mesh nebulizers with intermittent or continuous aerosol delivery and may be used with many different adapters and connections and all can influence their efficiency. The aim of the present work was to evaluate the effect functional principle, delivery technique, and connection used on aerosol delivered from four different nebulizers.

METHODS

Four nebulizers were used in the study; three of them were jet nebulizers (JNs; AeroEclipse, NebuTech, En ful Kit) and one of them was Aerogen Solo vibrating mesh nebulizers (VMN). AeroEclipse and NebuTech are intermittent output nebulizers, while the rest are continuous output nebulizers. Aerogen Solo was used with either a standard T-piece or Aerogen Ultra holding chamber, and En ful Kit was used with a standard T-piece or Circulaire II holding chamber. 2 ml of salbutamol was nebulized to determine the total emitted dose (TED) and aerodynamic droplet characteristics of the emitted aerosol from the 6 different sets (4 nebulizers with T-piece and 2 holding chambers).

RESULTS

The mean ± SD TED from VMN was significantly higher than all the JNs (p < 0.05). Aerogen Ultra with VMN did not show a significant effect on TED compare to T-piece, but it significantly increased (p < 0.05) fine particle dose (FPD; 3091.5 ± 189.4 μg) and fine particle fraction (FPF; 72.7 ± 3.6%). However, the Circulaire II with En ful Kit had significantly higher TED, FPD, and FPF compared to T-piece (p < 0.05). Intermittent JNs (AeroEclipse and NebuTech) had significantly higher TED (p < 0.05) compared to the continuous JNs (En ful Kit) with no significant effect on the other parameters studied. AeroEclipse had the highest MMAD and Aerogen Solo Ultra has the lowest in MMAD.

CONCLUSIONS

The functional principle, delivery technique, and connection used had a significant effect on aerosol delivered from nebulizers. VMNs are significantly better than JNs. Intermittent delivery has significantly better TED than continuous delivery. Holding chamber with both VMNs and JNs improved aerosol delivery compared to standard T-piece.

Effect of different accessory devices on the dose delivered from pressurised metred-dose inhalers

INTRODUCTIONS

Improved aerosol delivery of bronchodilators to chronic obstructive pulmonary disease (COPD) subjects is a cornerstone in the treatment approach. Drug delivery and response are improved with the use of accessory devices [spacers and valved holding chambers (VHCs)] with metred-dose inhalers (pMDIs). However, different accessory devices are available in the market with different properties that could affect aerosol delivery. Thus, this study aimed to assess the relative lung deposition and systemic bioavailability and compare bronchodilator response of salbutamol delivered using different accessory devices attached to pMDIs.

METHODS

Twelve healthy subjects and twelve COPD subjects inhaled 300 μg salbutamol (3 pMDI puffs) using five different accessory devices with either masks or mouthpieces (Able, Aerochamber plus flow Vu, Dolphin chamber, Tipshaler spacer, and modified Drink bottle spacer). Urine samples were collected thirty minutes post-dosing and cumulatively for the next twenty-four hours, to determine and compare the relative lung deposition [0-0.5 hour excretion of urinary salbutamol (USAL0.5)] and systemic bioavailability [0.5-24 hours excretion of urinary salbutamol (USAL24)] of salbutamol from the selected accessory devices. Also, the difference between pre and post-inhalation forced expiratory volume in one second (ΔFEV₁ %) of predicted was determined for each accessory device.

RESULTS

Urinary excretion of salbutamol (both USAL0.5 and USAL24 samples) in COPD subjects was significantly (P < .05) lower than in healthy subjects for all accessory devices. USAL0.5 and USAL24 in non-antistatic spacers (modified Drink bottle spacer and Dolphin chamber spacers) were significantly lower (P < .05) than that for antistatic spacers (Aerochamber plus flow Vu, Able and Tips-haler). No significant difference in USAL0.5 and USAL24 was observed between facemasks and mouthpieces. There was a significant difference (P < .05) in ΔFEV₁ % of predicted values between COPD subjects and healthy subjects. However, within the COPD group and the healthy group there was no significant difference in ΔFEV₁ % of predicted values between all accessory devices or between with mouthpiece or with a mask.

CONCLUSIONS

COPD subjects had lower aerosol delivered compared with healthy subjects. Anti-static accessory devices delivered a higher amount of aerosol compared with non-antistatic accessory devices. Even though the presence of a significant difference in aerosol delivery between non-antistatic and antistatic accessory devices no significant difference was found in the ΔFEV₁ % between all accessory devices.

Comparison of User Satisfaction and Preference with Inhalant Devices Between a Pressurized Metered-Dose Inhaler and Ellipta in Stable Asthma Patients: A Randomized, Crossover Study

Introduction

Inhalation therapy involves two types of adherence: adherence to the drug and adherence to the procedures for the inhalation device. User satisfaction and preference are key factors for maintaining good adherence of both types, and they should be evaluated based on three conditions being well maintained: asthma control level (ACL), adherence, and adequate device operability during usage duration. We compared user satisfaction and preference between a pressurized metered-dose inhaler (pMDI) and a dry powder inhaler (Ellipta), while maintaining the three conditions during usage in stable asthma patients.

Methods

In this open-label, randomized, two-way crossover study, patients with stable asthma [Asthma Control Questionnaire (ACQ) scores < 0.75] were classified into a 20–64-year age group (G1) and a ≥ 65-year age group (G2) and randomly assigned to either a formoterol/fluticasone combination (FFC) as the pMDI group or a vilanterol/fluticasone combination (VFC) as the Ellipta group. Satisfaction and preference levels were evaluated at week 4. ACL was measured using the ACQ and Japan Asthma Control Survey questionnaires at weeks 0 and 4. Device operability and respiratory resistance were also examined.

Results

Forty-four patients (23 G1, age 45.8 ± 1.9 years; 21 G2, 74.1 ± 1.3 years) were enrolled and maintained good ACL during the study. Adherence to FFC pMDI and VFC Ellipta was > 97% in all groups. Device operability did not differ significantly between FFC pMDI and VFC Ellipta in the G1 (p = 0.189) or G2 (p = 0.506) group. Overall satisfaction was marginally higher with the FFC pMDI than with the VFC Ellipta in G2 (p = 0.012) but non-significantly different in G1 (p = 0.733). Factors affecting overall satisfaction in G2 were difference of inhalation device and body mass index. Respiratory resistance did not change significantly over the study in G2.

Conclusion

Based on maintaining good ACL, adherence, and device operability, FFC pMDI showed significantly higher satisfaction and preference levels than VFC Ellipta in elderly persons.

Trial Registration

Japan Registry of Clinical Trials identifier, jRCTs041180001 (registered 21 August 2018).

Supplementary Information

The online version contains supplementary material available at 10.1007/s41030-021-00149-6.

Comparison of pulmonary deposition of nebulized 99m technetium-diethylenetriamine-pentaacetic acid through 3 inhalation devices in healthy dogs

Background

Inhalation treatment frequently is used in dogs and cats with chronic respiratory disease. Little is known however about the performance of delivery devices and the distribution of aerosolized drugs in the lower airways.

Objective

To assess the performance of 3 delivery devices and the impact of variable durations of inhalation on the pulmonary and extrapulmonary deposition of nebulized ^99mtechnetium‐diethylenetriamine‐pentaacetic acid (^99mTc‐DTPA).

Animals

Ten university‐owned healthy Beagle dogs.

Methods

Prospective crossover study. Dogs inhaled the radiopharmaceutical for 5 minutes either through the Aerodawg spacer with a custom‐made nose‐muzzle mask, the Aerochamber spacer with the same mask, or the Aerodawg spacer with its original nose mask. In addition, dogs inhaled for 1 and 3 minutes through the second device. Images were obtained by 2‐dimensional planar scintigraphy. Radiopharmaceutical uptake was calculated as an absolute value and as a fraction of the registered dose in the whole body.

Results

Mean (±SD) lung deposition for the 3 devices was 9.2% (±5.0), 11.4% (±4.9), and 9.3% (±4.6), respectively. Differences were not statistically significant. Uptake in pulmonary and extrapulmonary tissues was significantly lower after 1‐minute nebulization, but the mean pulmonary/extrapulmonary deposition ratio (0.38 ± 0.27) was significantly higher than after 5‐minute nebulization (0.16 ± 0.1; P = .03). No significant differences were detected after 3‐ and 5‐minute nebulization.

Conclusion and Clinical Importance

The performance of a pediatric spacer with a custom‐made mask is comparable to that of a veterinary device. One‐minute nebulization provides lower pulmonary uptake but achieves a better pulmonary/extrapulmonary deposition ratio than does 5‐minute nebulization.

Homemade valved holding chambers for children with airway hyperresponsiveness: A randomized crossover trial

BACKGROUND

During the COVID-19 pandemic, a metered-dose inhaler (MDI) with a valved holding chamber (VHC) is a preferred route of bronchodilator delivery. We have developed a new homemade VHC, made of a paper coffee cup, and a drinking water bottle. This study was conducted to compare the bronchodilator response in children with airway hyperresponsiveness after the use of our homemade VHC and that of a standard commercial one.

METHODS

In a randomized, two-period, two-sequence crossover trial, we recruited 20 children, aged 6-15 years, who had a greater than 12% increase in FEV₁ after inhaled salbutamol. They were randomized into Group A and B. Group A used our VHC on the first day and Aerochamber® on the second day. Group B used the same VHCs but in alternate sequence. Spirometries were performed before and after 400 µg of salbutamol, MDI was administered via those VHCs.

RESULTS

Baseline demographic data and spirometric values did not have statistically significant differences between group A and B and between the first and second day (p > .05). After giving salbutamol MDI, both VHCs produced significant increases in FVC, FEV₁ , and FEF_25-75% (p < .005). The improvement in FEV₁ did not significantly differ between our homemade VHC and Aerochamber® (p > .05).

CONCLUSION

Our homemade VHC is effective for an MDI bronchodilator delivery. Since it is very cheap and easy to make, it may be used as a disposable device to minimize airborne transmission especially when commercial VHC is not available.

Comparison between traditional and nontraditional add-on devices used with pressurised metered-dose inhalers

Add-on devices that are attached to metered-dose inhalers (MDIs) were introduced to improve aerosol delivery. The objective of this study was to determine the efficacy of drug delivery from an MDI when attached to different add-on devices at different inhalation volumes.

The total emitted dose (TED) of salbutamol was estimated for the MDI alone and the MDI connected to five different add-on devices (Able valved holding chamber, Tips-haler valved holding chamber, Aerochamber plus flow Vu valved holding chamber, Dolphin chamber, and a handmade water bottle spacer), at inhalation flow of 28.3 L·min⁻¹ with flow volume of 1, 2 and 4 L, assuming young child (aged <6 years), old child (>6 years) and adult inhalation volumes, respectively.

The TED% ranged between 84.1% and 87.2% at all inhalation volumes from the MDI alone, which was significantly greater than all MDI add-on device combinations (p<0.05). The TED% delivered to MDI sampling apparatus by a homemade water bottle spacer and Dolphin chamber, as non-antistatic add-on devices, ranged between 30.5% and 35.3%. However, washing these non-antistatic add-on devices with a light detergent before use improved their TED to range between 47.6% and 51.2%. Non-antistatic add-on devices had significantly lower TED (p<0.05) than that delivered by most antistatic add-on devices, which ranged from 51.3% to 71.6%.

This study suggests that antistatic add-on devices delivered much more aerosol than non-antistatic add-on devices. However, it may be advised to still use a non-antistatic add-on device, for the sake of solving the coordination problem, and wash it with light detergent before use to improve TED.

Antistatic add-on devices deliver much more aerosol from MDIs than non-antistatic add-on deviceshttps://bit.ly/3gSE5aR

Effectiveness of Spacer Devices on Preventing Undesirable Cardiovascular Effects of Inhaled Salbutamol

Background: Currently, there are no regulatory guidelines indicating spacer devices/valved holding chamber (VHC) should be used routinely during pulmonary function tests, and few studies evaluated if spacer devices reduce beta-agonist bronchodilators' side effects. Methods: A prospective study compared salbutamol's cardiovascular effects and bronchodilation response during spirometry tests with and without a spacer device/VHC. Heart rate (HR), the corrected QT interval (QTc), and systolic and diastolic blood pressure were measured 10 minutes after the first spirometry test, before the drug administration, and 20 minutes after inhalation in both groups. Spirometric parameters (forced expiratory volume in the first second [FEV1], forced vital capacity [FVC], and FEV1/FVC) were also measured for both groups. Results: HR and QTc increase were significantly higher in the pressurized meter dose inhalers alone group versus the VHC group [mean SD] [73.1 ± 10 bpm to 74.3 + 10 bpm, p = 0.021] and [median (25%-75% interquartile range)] [389 ms (381-404) to 398 ms (387-407), p = 0.045] vs. [mean SD] [75.4 ± 9 to 73.8 + 8 bpm, p = 0.4] and [median (25%-75% interquartile range)] [388 ms (347-408) to 385 ms (366-408), p = 0.35], respectively. FEV1 variation before and after salbutamol were similar between both groups. Discussion: Although VHC significantly reduces HR and QTc variation when using beta-agonist bronchodilators in healthy patients, no clinical repercussions of this variation were found in this study, since no event of tachycardia or pathological QTc was recorded. Conclusion: VHC has a diminished clinical impact for healthy patients when considering cardiovascular effects and spirometric parameters. Beta-agonist bronchodilators may be administrated despite the use of spacer devices in patients without known cardiovascular diseases. Its significance for other populations still needs to be determined.

Paediatric in vitro models showed significant variations in fluticasone proprionate output from valved holding chambers

AIM

We compared potential differences in drug delivery between different valved holding chambers (VHCs) used by asthma patients, with and without facemasks.

METHODS

An in vitro study design was created using a fluticasone propionate (FP) pressurised metered dose inhaler (pMDI) connected to a VHC. VHCs without facemasks and with sealed and unsealed facemasks were placed against face models that mimicked the features of a 1-year-old infant and a 4-year-old child. We analysed the amount of FP deposited on the filter in the face model after five breaths with a tidal volume of 75 mL.

RESULTS

Our measurements showed significant differences in the amounts of FP deposited on the filters, even without facemasks. The amount of FP delivered through the VHC and facemask combinations differed significantly, depending on the degree of the lack of facemask to face seal. All the tested VHCs showed significantly better drug output without a facemask.

CONCLUSION

The VHC and facemasks chosen had a considerable and significant impact on FP delivery. The facemask seal should be checked whenever a VHC facemask combination is used. Young children should be taught to use the VHC mouthpiece as early as possible to optimise FP delivery and achieve more effective asthma therapy.

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.

Critical Errors in Inhaler Technique among Children Hospitalized with Asthma

Past studies have not evaluated inhaler use in hospitalized children with asthma. The objectives of this study were to evaluate inhaler technique in hospitalized pediatric patients with asthma and identify risk factors for improper use. We conducted a prospective cross-sectional study in a tertiary children's hospital for children 2-16 years of age admitted for an asthma exacerbation, and inhaler technique demonstrations were analyzed. Of 113 participants enrolled, 55% had uncontrolled asthma, and 42% missed a critical step in inhaler technique. More patients missed a critical step when they used a spacer with mouthpiece instead of a spacer with mask (75% [51%-90%] vs 36% [27%-46%]) and were older (7.8 [6.7-8.9] vs 5.8 [5.1-6.5] years). Patients using the spacer with mouthpiece remained significantly more likely to miss a critical step when adjusting for other clinical covariates (odds ratio 6.95 [1.71-28.23], P = .007). Hospital-based education may provide teachable moments to address poor proficiency, especially for older children using a mouthpiece.

Delivering drugs to the lungs: The history of repurposing in the treatment of respiratory diseases

The repurposing of drug delivery by the pulmonary route has been applied to treatment and prophylaxis of an increasingly wide range of respiratory diseases. Repurposing has been most successful for the delivery of inhaled bronchodilators and corticosteroids in patients with asthma and chronic obstructive pulmonary disease (COPD). Repurposing utilizes the advantages that the pulmonary route offers in terms of more targeted delivery to the site of action, the use of smaller doses, and a lower incidence of side-effects. Success has been more variable for other drugs and treatment indications. Pulmonary delivery is now well established for delivery of inhaled antibiotics in cystic fibrosis (CF), and in the treatment of pulmonary arterial hypertension (PAH). Other inhaled treatments such as those for idiopathic pulmonary fibrosis (IPF), lung transplant rejection or tuberculosis may also become routine. Repurposing has progressed in parallel with the development of new drugs, inhaler devices and formulations.

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

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

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.

Pulmonary drug delivery system: newer patents

Inhalational route for drug delivery and desired effects has been known since centuries. This lung-targeted therapy has benefited asthmatics and those with chronic respiratory problems. The technique has evolved greatly from crude pots and pipes to modern sophisticated drug-dispensing devices. This mode is effective, rapid and safe. Its outcome, however, is majorly determined by drug formulation, device structure and patient's coordinating skill. In spite of great advances in this field, more efforts are required to meet the unmet needs. This noninvasive mode is being increasingly studied for transfer of drugs for systemic action with promising results. The present article is an attempt to capture the recent development and progress in this field and review relevant newer patents.

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).

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

SPECT-CT Comparison of Lung Deposition using a System combining a Vibrating-mesh Nebulizer with a Valved Holding Chamber and a Conventional Jet Nebulizer: a Randomized Cross-over Study

PURPOSE

To compare in vivo the total and regional pulmonary deposition of aerosol particles generated by a new system combining a vibrating-mesh nebulizer with a specific valved holding chamber and constant-output jet nebulizer connected to a corrugated tube.

METHODS

Cross-over study comparing aerosol delivery to the lungs using two nebulizers in 6 healthy male subjects: a vibrating-mesh nebulizer combined with a valved holding chamber (Aerogen Ultra®, Aerogen Ltd., Galway, Ireland) and a jet nebulizer connected to a corrugated tube (Opti-Mist Plus Nebulizer®, ConvaTec, Bridgewater, NJ). Nebulizers were filled with diethylenetriaminepentaacetic acid labelled with technetium-99 m (^99mTc-DTPA, 2 mCi/4 mL). Pulmonary deposition of ^99mTc-DTPA was measured by single-photon emission computed tomography combined with a low dose CT-scan (SPECT-CT).

RESULTS

Pulmonary aerosol deposition from SPECT-CT analysis was six times increased with the vibrating-mesh nebulizer as compared to the jet nebulizer (34.1 ± 6.0% versus 5.2 ± 1.1%, p < 0.001). However, aerosol penetration expressed as the three-dimensional normalized ratio of the outer and the inner regions of the lungs was similar between both nebulizers.

CONCLUSIONS

This study demonstrated the high superiority of the new system combining a vibrating-mesh nebulizer with a valved holding chamber to deliver nebulized particles into the lungs as comparted to a constant-output jet nebulizer with a corrugated tube.

The History of Therapeutic Aerosols: A Chronological Review

In 1956, Riker Laboratories, Inc., (now 3 M Drug Delivery Systems) introduced the first pressurized metered dose inhaler (MDI). In many respects, the introduction of the MDI marked the beginning of the modern pharmaceutical aerosol industry. The MDI was the first truly portable and convenient inhaler that effectively delivered drug to the lung and quickly gained widespread acceptance. Since 1956, the pharmaceutical aerosol industry has experienced dramatic growth. The signing of the Montreal Protocol in 1987 led to a surge in innovation that resulted in the diversification of inhaler technologies with significantly enhanced delivery efficiency, including modern MDIs, dry powder inhalers, and nebulizer systems. The innovative inhalers and drugs discovered by the pharmaceutical aerosol industry, particularly since 1956, have improved the quality of life of literally hundreds of millions of people. Yet, the delivery of therapeutic aerosols has a surprisingly rich history dating back more than 3500 years to ancient Egypt. The delivery of atropine and related compounds has been a crucial inhalation therapy throughout this period and the delivery of associated structural analogs remains an important therapy today. Over the centuries, discoveries from many cultures have advanced the delivery of therapeutic aerosols. For thousands of years, therapeutic aerosols were prepared by the patient or a physician with direct oversight of the patient using custom-made delivery systems. However, starting with the Industrial Revolution, advancements in manufacturing resulted in the bulk production of therapeutic aerosol delivery systems produced by people completely disconnected from contact with the patient. This trend continued and accelerated in the 20th century with the mass commercialization of modern pharmaceutical inhaler products. In this article, we will provide a summary of therapeutic aerosol delivery from ancient times to the present along with a look to the future. We hope that you will find this chronological summary intriguing and informative.

Dilemmas, Confusion, and Misconceptions Related to Small Airways Directed Therapy

During the past decade, there has been increasing evidence that the small airways (ie, airways < 2 mm in internal diameter) contribute substantially to the pathophysiologic and clinical expression of asthma and COPD. The increased interest in small airways is, at least in part, a result of innovation in small-particle aerosol formulations that better target the distal lung and also advanced physiologic methods of assessing small airway responses. Increasing the precision of drug deposition may improve targeting of specific diseases or receptor locations, decrease airway drug exposure and adverse effects, and thereby increase the efficiency and effectiveness of inhaled drug delivery. The availability of small-particle aerosols of corticosteroids, bronchodilators, or their combination enables a higher total lung deposition and better peripheral lung penetration and provides added clinical benefit, compared with large-particle aerosol treatment. However, a number of questions remain unanswered about the pragmatic approach relevant for clinicians to consider the role of small airways directed therapy in the day-to-day management of asthma and COPD. We thus have tried to clarify the dilemmas, confusion, and misconceptions related to small airways directed therapy. To this end, we have reviewed all studies on small-particle aerosol therapy systematically to address the dilemmas, confusion, and misconceptions related to small airways directed therapy.

Inhalation device requirements for patients' inhalation maneuvers

BACKGROUND

Inhaled drugs are the mainstay of treatment for lung diseases such as asthma and chronic obstructive pulmonary disease. However, failure to use inhalation devices correctly can lead to a poorly controlled status. A vast number of inhalation devices exist and each device has specific requirements to achieve optimum inhalation of the drug. Currently, there is no overview of inhalation requirements considering all devices. This article presents a review of the literature on different inhalation device requirements and incorporates the data into a new inhalation flow algorithm.

METHODS

Data from literature on commercially available inhalation devices were evaluated and parameters, such as inhalation flow rate, flow acceleration, inhalation volume, and inspiration time assessed for the required inhalation maneuver specific to the device. All agreed upon data points were used to develop an inhalation flow algorithm.

RESULTS

The literature analysis revealed availability of robust data for the required inhalation flow characteristics for most devices and thus for the development of an algorithm. For those devices for which these parameters are not published, the minimum required flow criteria were defined based on published data regarding individual aspects of aerosol quality.

CONCLUSIONS

This review provides an overview of inhalation devices available on the market regarding requirements for an acceptable inhalation maneuver and shows which goals should be achieved in terms of inhalation flows. The presented algorithm can be used to develop a new computer based measurement system which could help to test and train patients' individual inhalation maneuvers with their inhalation devices.

The Digital Asthma Patient: The History and Future of Inhaler Based Health Monitoring Devices

The wave of digital health is continuously growing and promises to transform healthcare and optimize the patients' experience. Asthma is in the center of these digital developments, as it is a chronic disease that requires the continuous attention of both health care professionals and patients themselves. The accurate and timely assessment of the state of asthma is the fundamental basis of digital health approaches and is also the most significant factor toward the preventive and efficient management of the disease. Furthermore, the necessity of inhaled medication offers a basic platform upon which modern technologies can be integrated, namely the inhaler device itself. Inhaler-based monitoring devices were introduced in the beginning of the 1980s and have been evolving but mainly for the assessment of medication adherence. As technology progresses and novel sensing components are becoming available, the enhancement of inhalers with a wider range of monitoring capabilities holds the promise to further support and optimize asthma self-management. The current article aims to take a step for the mapping of this territory and start the discussion among healthcare professionals and engineers for the identification and the development of technologies that can offer personalized asthma self-management with clinical significance. In this direction, a technical review of inhaler based monitoring devices is presented, together with an overview of their use in clinical research. The aggregated results are then summarized and discussed for the identification of key drivers that can lead the future of inhalers.

A Rationale for Going Back to the Future: Use of Disposable Spacers for Pressurised Metered Dose Inhalers

The introduction of pressurised metered dose inhalers (MDIs) in the mid-1950s completely transformed respiratory treatment. Despite decades of availability and healthcare support and development of teaching aids and devices to promote better use, poor pMDI user technique remains a persistent issue. The main pMDI user aid is the spacer/valved holding chamber (VHC) device. Spacer/chamber features (size, shape, configuration, construction material, and hygiene considerations) can vie with clinical effectiveness (to deliver the same dose as a correctly used pMDI), user convenience, cost, and accessibility. Unsurprisingly, improvised, low-cost alternatives (plastic drink bottles, paper cups, and paper towel rolls) have been pressed into seemingly effective service. A UK law change permitting schools to hold emergency inhalers and spacers has prompted a development project to design a low-cost, user-friendly, disposable, and recyclable spacer. This paper spacer requires neither preuse priming nor washing, and has demonstrated reproducible lung delivery of salbutamol sulphate pMDI, comparable to an industry-standard VHC, an alternative paperboard VHC, and pMDI alone. This new device appears to perform better than these other VHC devices at the low flow rates thought achievable by paediatric patients. The data suggest that this disposable spacer may have a place in the single-use emergency setting.

Industry guidance for the selection of a delivery system for the development of novel respiratory products

INTRODUCTION

Respiratory diseases remain a target for improved forms of inhalation therapy. However, there are neither regulatory preferences for one type of device over another, nor well-recognized guidelines. This guidance describes factors that should be considered to optimize the choice of delivery system.

AREAS COVERED

This article summarizes the different types of delivery systems with key technical and commercial considerations for selection. It highlights current market trends and opportunities for the future, based on the author's experience of more than 20 years in this field.

EXPERT OPINION

For a generic drug, low device cost favors a capsule dry powder inhaler (DPI) or a propellant-based metered-dose inhaler (pMDI). Novel particle engineering approaches may allow close matching to the innovator product performance. For novel drugs, most companies favor a bespoke DPI, adding patent protection and aiding brand recognition, despite being expensive to develop. Device features may add differentiation, but "no outcome, no income." Patient technique and adherence remain problematic, compounded by age, although accessories, including monitors, can help. There are few modern medicines available in nebulized form, so there is value in fast-tracking the nebulized formulations from Phase I studies through to market in parallel to the chosen inhaler.

In vitro characterization of the OptiChamber Diamond valved holding chamber

BACKGROUND

Use of a valved holding chamber (VHC) in conjunction with a pressurized metered dose inhaler (pMDI) can reduce issues relating to poor actuation-inhalation coordination and potentially improve the lung deposition of aerosol, compared with use of a pMDI alone. However, the performance of a VHC is influenced by different device-related factors, including the size and shape of the VHC and the material it is manufactured from (conventional versus antistatic). This study aimed to provide an in vitro characterization of an antistatic VHC, the OptiChamber Diamond VHC, comparing the aerodynamic particle size distribution of aerosol delivered via this VHC with results from a second antistatic VHC and a conventional VHC.

METHODS

The pMDI drug formulations (albuterol, suspension; beclomethasone dipropionate, solution) were connected to a Next Generation Impactor, either directly (pMDI alone tests) or via a VHC (VHC tests). The pMDIs were actuated (×10 per product pair) and tested at extraction flow rates of 15 L/min and 30 L/min, without any time delay between actuation and inhalation. Dose delivery using the two pMDI drug formulations was compared, and is presented with reference to key aerodynamic particle size parameters.

RESULTS

Compared with tests on pMDIs alone, use of a VHC increased the dose of aerosol within the respirable range, particularly at a 15 L/min flow rate. Between-VHC comparisons indicated that the two antistatic VHCs were equivalent. Delivery of albuterol appeared to be influenced by the VHC used, but beclomethasone dipropionate seemed unaffected.

CONCLUSIONS

The two antistatic VHCs were equivalent for both pMDI brands. Aerosol delivered from the antistatic VHCs at 15 L/min had a higher proportion of fine particles compared with the conventional VHC.

Opportunities in respiratory drug delivery

A wide range of asthma and chronic obstructive pulmonary disease products are soon to be released onto the inhaled therapies market and differentiation between these devices will help them to gain market share over their competitors. Current legislation is directing healthcare towards being more efficient and cost-effective in order to continually provide quality care despite the challenges of aging populations and fewer resources. Devices and drugs that can be differentiated by producing improved patient outcomes would, therefore, be likely to win market share. In this perspective article, the current and potential opportunities for the successful delivery and differentiation of new inhaled drug products are discussed.