Low incidence of paradoxical bronchoconstriction with bronchodilator drugs administered by Respimat Soft Mist inhaler: results of phase II single-dose crossover studies

Self-sealing MEMS spray-nozzles to prevent bacterial contamination of portable inhalers for aqueous drug delivery

Pulmonary drug delivery by portable inhalers is the gold standard in lung disease therapy. An increasing focus on environmentally friendly inhalation currently spurs the development of propellant-free devices. However, the absence of propellants in the drug creates a need for suitable sealing systems that can ensure the pathogenic safety of devices. Traditionally, liquid drug inhalers incorporate a spray nozzle and a separate check valve. Here we show a fully integrated MEMS-based spray system for aqueous drug solutions and demonstrate its bacterial safety. The device comprises a thin silicon membrane with spray orifices, which self-seal against a compliant parylene valve seat underneath. This sealing system prevents bacterial ingrowth in its default closed state, while actuation lifts the membrane from the valve seat upon pressurization and sprays an inhalable aerosol from the nozzles. To seal against bacterial contamination effectively, we found that a contact force between the valve seat and the membrane (featuring the spray nozzles) is needed. In our testing, both self-sealing and an otherwise identical unvalved version of the spray chip can be bacterially safe in continued use when thoroughly cleaned of excess fluids and subjected to low bacterial loads for brief periods. However, when directly exposed to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10^{7}$$\end{document}107 CFU/ml of our test organism Citrobacter rodentium for 24 h, unvalved systems become contaminated in nearly 90% of cases. In contrast, self-sealing spray chips reduced contamination probability by 70%. This development may enable preservative-free drug formulations in portable inhalers that use propellant-free aqueous drug solutions.

Methodological evaluation of human research on asthmagenicity and occupational cleaning: a case study of quaternary ammonium compounds ("quats")

In this paper, we review methodological approaches used in studies that evaluated the association between occupational exposure to quaternary ammonium compounds (quats) and occupational asthma. This association is of interest because quats are a common active ingredient of disinfectants and have been linked to work-related asthma in some circumstances. However, any evidence-based assessment of an exposure-outcome association needs to consider both strengths and limitations of the literature. We focus on publications cited by various US and international organizations. Eighteen investigations included in the review fall into two broad categories: case reports and challenge studies of individual patients and population studies that examined the association between quats and asthma occurrence in groups of subjects. We evaluated these studies guided by questions that address whether: exposure data on specific quat(s) and other agents that may cause asthma were included, new asthma cases were differentiated from asthma exacerbation, and information on respiratory sensitivity versus irritation was given. We also assessed consistency across studies. Studies of individual patients, particularly those that provided detailed information on challenge test results, document cases of asthma induced by exposure to quats. By contrast, studies of occupational groups with the highest potential for quats exposure (e.g., cleaners and farmers) do not consistently report increased incidence of asthma due specifically to quats. The unresolved methodological issues include: poor understanding of exposure pathways considering that quats are non-volatile, lack of quantitative data allowing for identification of an asthmagenicity threshold, insufficient information on whether quats are sensitizers or act via dose-dependent irritation or some other mechanism, and inability to quantify risk of new-onset asthma attributable to quats. Another important area of uncertainty is the lack of information on the specific quats being used. There is also a lack of data capable of distinguishing the effects of quats from those of other chemical and biological workplace exposures. The current state-of-the-science does not allow a proper assessment of the potential link between quats and occupational asthma.

The function and performance of aqueous aerosol devices for inhalation therapy

OBJECTIVES

In this review paper, we explore the interaction between the functioning mechanism of different nebulizers and the physicochemical properties of the formulations for several types of devices, namely jet, ultrasonic and vibrating-mesh nebulizers; colliding and extruded jets; electrohydrodynamic mechanism; surface acoustic wave microfluidic atomization; and capillary aerosol generation.

KEY FINDINGS

Nebulization is the transformation of bulk liquids into droplets. For inhalation therapy, nebulizers are widely used to aerosolize aqueous systems, such as solutions and suspensions. The interaction between the functioning mechanism of different nebulizers and the physicochemical properties of the formulations plays a significant role in the performance of aerosol generation appropriate for pulmonary delivery. Certain types of nebulizers have consistently presented temperature increase during the nebulization event. Therefore, careful consideration should be given when evaluating thermo-labile drugs, such as protein therapeutics. We also present the general approaches for characterization of nebulizer formulations.

SUMMARY

In conclusion, the interplay between the dosage form (i.e. aqueous systems) and the specific type of device for aerosol generation determines the effectiveness of drug delivery in nebulization therapies, thus requiring extensive understanding and characterization.

Lack of paradoxical bronchoconstriction after administration of tiotropium via Respimat® Soft Mist™ Inhaler in COPD

Bronchoconstriction has been reported in asthma and chronic obstructive pulmonary disease (COPD) patients after administration of some aqueous inhalation solutions. We investigated the incidence of this event during long-term clinical trials of tiotropium delivered via Respimat^® Soft Mist™ Inhaler (SMI). We retrospectively analyzed pooled data from two identical Phase III clinical trials, in which 1990 patients with COPD received 48 weeks’ treatment with once-daily tiotropium (5 or 10 μg) or placebo inhaled via Respimat^® SMI. We recorded the incidence of bronchospasm and of a range of respiratory events that could suggest bronchoconstriction during the first 30 minutes after inhalation of study treatment on each of the eight test days. No patients reported bronchospasm. Six patients (0.3%) reported a combination of at least two events suggestive of bronchoconstriction, and 21 (1.1%) reported either rescue medication use or a respiratory adverse event. Asymptomatic falls in forced expiratory volume in one second (FEV₁) of ≥15% were recorded on all test days, with no change in incidence over time, and affected 8.2% of those in the tiotropium groups and 14.5% of those on placebo. In COPD patients receiving long-term treatment with tiotropium 5 or 10 μg via Respimat^® SMI, no bronchospasm was recorded, and the number of events possibly indicative of paradoxical bronchoconstriction was very low.

[Respimat®, first Soft Mist™ inhaler: new perspectives in the management of COPD]

INTRODUCTION

In COPD, inhaler choice should be based on the likelihood that the patient will be able to use the device correctly in order to favour adherence and compliance, and therefore treatment efficacy. SATE OF THE ART: Performances of usual inhalers are limited by the necessity of a good coordination of patient inspiration and inhaler activation (pressurized metered dose inhalers), or a sufficient inspiratory flow (dry powder inhalers). Respimat®, the first "Soft Mist™ inhaler" (SMI), releases the drug solution as a low and sustained soft mist, so that lung deposition is both improved and reproducible.

PERSPECTIVES

In clinical studies, Respimat® has been shown to allow equivalent bronchodilator response and tolerability to metered dose or dry powder inhalers, but with lower doses of active drugs. Furthermore, studies assessing inhaler preference in COPD showed that patients preferred Respimat® to usual inhalers.

CONCLUSION

Respimat® SMI offers new perspectives for the management of chronic respiratory diseases, particularly in newly diagnosed or poorly compliant patients.

Clinical efficacy and safety of the combination of ipratropium bromide and fenoterol inhaled via the Respimat Soft Mist inhaler for relief of airflow obstruction

Bronchodilators are key drugs in symptomatic as well as maintenance treatment of obstructive lung diseases such as chronic obstructive pulmonary disease and asthma. The short-acting anticholinergic ipratropium bromide and the short-acting beta(2)-adrenergic receptor agonist fenoterol hydrobromide have been available for combined use both as a pressurized metered-dose inhaler and as a solution for nebulization. Their combination at half the dose in the novel device, the Respimat Soft Mist inhaler (RMT), has been shown to provide therapeutic equivalence to their combination into a conventional pressurized metered-dose inhaler, both in terms of efficacy and safety in patients with chronic obstructive pulmonary disease or asthma, both adults and children. Dose reduction with the RMT has been made possible due to the physical characteristics of the aerosol cloud emitted from the RMT, facilitating correct inhalation and ensuring higher pulmonary deposition of the aerosolized bronchodilators. Post-marketing studies using validated questionnaires confirm a high level of satisfaction with the performance and convenience of the RMT device, a large majority of patients preferring the RMT to other inhaler systems.

Use of Respimat Soft Mist inhaler in COPD patients

Events of the past decade have stimulated development of new drug formulations and delivery devices that have improved the efficiency, ease of use, and environmental impact of inhaled drug therapy. Respimat^® Soft Mist™ Inhaler is a novel, multidose, propellant-free, hand-held, liquid inhaler that represents a new category of inhaler devices. The aerosol cloud generated by Respimat contains a higher fraction of fine particles than most pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs), and the aerosol spray exits the inhaler more slowly and for a longer duration than with pMDIs. This translates into higher lung drug deposition and lower oropharyngeal deposition, making it possible to give lower nominal doses of delivered drugs without lowering efficacy. In clinical trials in patients with COPD, bronchodilator drugs delivered from Respimat were equally effective at half of the dose delivered from a pMDI. In one study of inhaler preference, Respimat was preferred over the pMDI by patients with COPD and other obstructive lung diseases. Respimat is a valuable addition to the range of inhaler devices available to the patient with COPD.

Acute local tolerability of acidic aqueous vehicles delivered via Respimat Soft Mist Inhaler in hyperreactive asthma patients

BACKGROUND

Acidic inhalers can be associated with increased adverse reactions.

OBJECTIVES

This study aimed to determine the acute local tolerability of acidic aqueous placebo formulations delivered via Respimat Soft Mist Inhaler (SMI) and placebo chlorofluorocarbon metered dose inhaler (CFC-MDI).

METHODS

A single-dose (four inhalations), randomized, double-blind within Respimat SMI device, four-way crossover study in asthma patients with documented bronchial hyperresponsiveness was used. Patients received acidic placebo solutions [pH 2.7, 3.4 or 7.0 (neutral)], delivered via Respimat SMI or placebo CFC-MDI. The primary endpoint was the largest decrease in forced expiratory volume in 1 s (FEV(1)) from baseline to 0-30 min after dosing. Secondary endpoints included spirometry, paradoxical bronchoconstriction (defined as a fall in FEV(1) >or=15% below baseline within 30 min of dosing), cough episodes and adverse events.

RESULTS

Thirty-two patients were included in the per-protocol population (mean age 27 years, 62.5% males). The mean percentage decrease in FEV(1) was comparable between treatment groups: -1.6% (Respimat SMI pH 2.7), -1.8% (Respimat SMI pH 7.0), -1.9% (CFC-MDI), and -2.3% (Respimat SMI pH 3.4); no patient experienced paradoxical bronchoconstriction. The mean number of cough episodes was significantly lower in the Respimat SMI pH 2.7 group versus CFC-MDI (p = 0.0165). No patient used rescue medication. Only 3 patients experienced at least one adverse event.

CONCLUSIONS

The Respimat SMI pH 2.7 placebo solution does not induce adverse events in these patients. Compared with the CFC-MDI placebo suspension, Respimat SMI is a well-tolerated inhaled medication delivery system that can accommodate medication formulations with a wide range of pH solutions.

Low incidence of paradoxical bronchoconstriction in asthma and COPD patients during chronic use of Respimat soft mist inhaler

Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler that offers improved lung deposition compared with chlorofluorocarbon metered dose inhalers (CFC-MDIs). Bronchodilators administered via Respimat SMI are preserved and stabilised with low concentrations of benzalkonium chloride and ethylene diamine tetra-acetic acid, both of which have been reported to cause dose-related paradoxical bronchoconstriction. The aim of this analysis was to compare the incidence of paradoxical bronchoconstriction after chronic use of bronchodilators via Respimat SMI and CFC-MDI. Data from three clinical trials, in which patients with asthma or chronic obstructive pulmonary disease (COPD) received ipratropium bromide alone or in combination with fenoterol hydrobromide, or placebo via Respimat SMI or CFC-MDI for 12 weeks, were included in the analysis. In order to evaluate the risk of paradoxical bronchoconstriction, we identified four respiratory events that might have occurred within 30 min of inhalation on four test days; these were: 'bronchospasm', 'other respiratory adverse events', 'rescue medication use' and 'asymptomatic drop in FEV(1) 15% from baseline'. In total, 631 asthma and 1538 COPD patients participated in the three studies. No occurrences of bronchospasm were reported with Respimat SMI on any test day. Overall, the incidence of respiratory events possibly indicative of paradoxical bronchoconstriction was low and similar for both devices. There was no increase in the incidence of events during 12 weeks' treatment. Delivery of bronchodilators by Respimat SMI is safe with regard to paradoxical bronchoconstriction during chronic use in patients with asthma or COPD.

Inhaled ethanolic and aqueous solutions via Respimat Soft Mist Inhaler are well-tolerated in asthma patients

BACKGROUND

Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler offering improved lung deposition compared with other devices. Bronchodilators administered via Respimat SMI are preserved and stabilized with benzalkonium chloride (BAC) and ethylene diamine tetra-acetic acid (EDTA); both have been reported to cause paradoxical bronchoconstriction if a threshold dose is exceeded.

OBJECTIVE

The aim of this randomized, double-blind, three-period, crossover study was to establish that the safety of inhaled ethanolic and aqueous placebo solutions (containing BAC and EDTA) is equivalent to that of inhaled normal saline solution when administered to asthma patients via Respimat SMI.

METHODS

Thirty-seven asthma patients with airway hyper-reactivity were randomized to receive four actuations of each of the following three treatments via Respimat SMI, one on each of 3 study days: ethanolic placebo (12 microl 96% ethanol + 0.13 mug EDTA/actuation), aqueous placebo (12 microl water + 5.5 microg EDTA + 1.1 mug BAC/actuation), and normal saline (12 microl 0.9% sodium chloride/actuation). Pulmonary function tests were performed at baseline and at 5, 15, 30, 60, 120 and 180 min after inhalation; the primary endpoint was the lowest FEV(1) recorded between 0 and 30 min.

RESULTS

The mean lowest FEV(1) recorded between 0 and 30 min after inhalation minus the study day baseline was -0.090 litres for ethanolic placebo, -0.121 litres for aqueous placebo and -0.094 litres for normal saline (SEM 0.034 litres for all). The mean treatment differences were: ethanolic placebo versus normal saline 0.004 litres (90% CI -0.075-0.083 litres, p = 0.002), and aqueous placebo versus normal saline -0.028 litres (90% CI -0.107-0.052 litres, p = 0.006). Since both 90% CIs fell within the pre-determined equivalence region of +/-0.15 litres, both treatments were considered equivalent to normal saline.

CONCLUSION

Ethanolic and aqueous solutions administered via Respimat SMI are safe with regard to paradoxical bronchoconstriction in asthma patients with airway hyper-reactivity.