Comparison of bronchodilator responses of levosalbutamol and salbutamol given via a pressurized metered dose inhaler: a randomized, double blind, single-dose, crossover study

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

The Use of a Three-Fluid Atomising Nozzle in the Production of Spray-Dried Theophylline/Salbutamol Sulphate Powders Intended for Pulmonary Delivery

The aim of this study was to investigate the use of a three-fluid atomising nozzle in a lab-scale spray dryer for the production of dry powders intended for pulmonary delivery. Powders were composed of salbutamol sulphate and theophylline in different weight ratios. The three-fluid nozzle technology enabled powders containing a high theophylline content to be obtained, overcoming the problems associated with its relatively low solubility, by pumping two separate feed solutions (containing the two different active pharmaceutical ingredients (APIs)) into the spray dryer via two separate nozzle channels at different feed rates. The final spray-dried products were characterized in terms of morphology, solid-state properties and aerosolization performance, and were compared with an equivalent formulation prepared using a standard two-fluid atomising nozzle. Results confirmed that most of the powders made using the three-fluid atomising nozzle met the required standards for a dry powder inhaler formulation in terms of physical characteristics; however, aerosolization characteristics require improvement if the powders are to be considered suitable for pulmonary delivery.

Low-dose l-isoproterenol versus salbutamol in hospitalized pediatric patients with severe acute exacerbation of asthma: A double-blind, randomized controlled trial

BACKGROUND

Although the guidelines in most countries do not recommend continuous inhalation of l-isoproterenol to treat pediatric patients with acute severe exacerbation of asthma, lower dose of l-isoproterenol has been widely used in Japan. To determine whether the efficacy of low-dose l-isoproterenol was superior to that of salbutamol, we conducted a double-blind, randomized controlled trial.

METHODS

Hospitalized patients aged 1-17 years were eligible if they had severe asthma exacerbation defined by the modified pulmonary index score (MPIS). Patients were randomly assigned (1:1) to receive inhalation of l-isoproterenol (10 μg/kg/h) or salbutamol (500 μg/kg/h) for 12 hours via a large-volume nebulizer with oxygen. The primary outcome was the change in MPIS from baseline to 3 hours after starting inhalation. Trial registration number UMIN000001991.

RESULTS

From December 2009 to October 2013, 83 patients (42 in the l-isoproterenol group and 41 in the salbutamol group) were enrolled into the study. Of these, one patient in the l-isoproterenol group did not receive the study drug and was excluded from the analysis. Compared with salbutamol, l-isoproterenol reduced MPIS more rapidly. Mean (SD) changes in MPIS at 3 hours were -2.9 (2.5) in the l-isoproterenol group and -0.9 (2.3) in the salbutamol group (difference -2.0, 95% confidence interval -3.1 to -0.9; P < 0.001). Adverse events occurred in 1 (2%) and 11 (27%) patients in the l-isoproterenol and salbutamol groups, respectively (P = 0.003). Hypokalemia and tachycardia occurred only in the salbutamol group.

CONCLUSIONS

Low-dose l-isoproterenol has a more rapid effect with fewer adverse events than salbutamol.

Determining the optimal time to assess the reversibility of airway obstruction

Context:

The optimal time to interpret bronchodilator reversibility remains controversial. This time may affect a positive diagnosis and manage asthma and chronic obstructive pulmonary disease (COPD).

Aims:

We sought to document the time when maximum respiratory function is reached after inhalation of salbutamol and to define the optimal time of bronchodilator response to assess the reversibility or non reversibility of airway obstruction.

Subjects and Methods:

This prospective analytical study was spread over 8 months and included 58 patients with asthma or COPD with airway obstruction. Spirometry was performed before and at 5, 10, 15, 20, and 30 min after salbutamol inhalation (200 mcg) administered through pressurized metered-dose inhalers and large volume spacer.

Results:

After salbutamol inhalation, the mean individual peak bronchodilation occurred at 20 min for the forced vital capacity and at 30 min for the forced expiratory volume in 1 s. The percentage of reversible patients in our sample was guideline dependent. It increased from 53% to 67.2% when using the American Thoracic Society/European Respiratory Society definition compared to using the Global Initiative for Chronic Obstructive Lung Disease. The maximum number of reversible patients was significantly different at 20 min compared to 5 and 10 min.

Conclusions:

Interpreting bronchodilator reversibility after 20 min was the ideal time to judge the reversibility or nonreversibility in obstructive ventilatory disorders in adults.

Racemic salbutamol and levosalbutamol in mild persistent asthma: A comparative study of efficacy and safety

Aim:

The effect of monotherapy with racemic salbutamol and levosalbutamol on symptoms, quality of life, and pulmonary function has been assessed and compared in mild persistent asthma.

Materials and Methods:

A randomized, open, parallel clinical study was conducted on 60 patients of mild persistent asthma. After baseline assessments, salbutamol was prescribed to 30 patients and levosalbutamol to another 30 for 4 weeks. The efficacy variables were change in asthma symptom scoring, pulmonary function test, and Mini Asthma Quality of Life Questionnaire (MiniAQLQ) scoring. At follow-up, the patients were re-evaluated and analyzed by statistical tools.

Results:

Shortness of breath (P<0.001), chest tightness (P=0.033), wheeze (P=0.01), cough (P=0.024), and overall asthma symptom score (P<0.001) were significantly decreased in the levosalbutamol group in comparison to the salbutamol group. Results of MiniAQLQ revealed that improvement in symptoms (P=0.018), activity limitations (P=0.03), environmental stimuli (P=0.013)-related scoring and overall MiniAQLQ scoring (P<0.001) was statistically significant in the levosalbutamol group. Percentage reversibility of forced expiratory volume at one second (P=0.034), forced vital capacity (P=0.029), peak expiratory flow rate (P=0.0003) was found to be superior in the levosalbutamol group.

Conclusion:

Levosalbutamol was found to be superior compared to recemic salbutamol in mild persistent asthma.

Levosalbutamol for chronic obstructive pulmonary disease: a treatment evaluation

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is an inflammatory disorder associated with considerable morbidity and mortality. β2-adrenoceptor agonists (β2-agonists) act by stimulating the β2-adrenoceptor present on smooth muscle and other cells in the airways, resulting in bronchodilatation. β2-agonists play a central role in the treatment of breathlessness in patients with COPD. Salbutamol is a chiral drug with (R)- and (S)- isomers. Almost all β2-agonists that are currently used are racemic mixtures of (R)- and (S)-salbutamol.

AREAS COVERED

(R)-salbutamol alone (Xenopex®, generically known as levosalbutamol) is now indicated for the treatment or prevention of bronchospasm with reversible obstructive airway disease. This evaluation demonstrates that (R)-salbutamol provides a beneficial β2-agonist effect at a cellular level and in experimental models of airways disease. Furthermore, we demonstrate that (S)-salbutamol opposes the desirable effects of (R)-salbutamol and can actually cause features of asthma and COPD in vitro and in experimental asthma.

EXPERT OPINION

Despite this strong body of preclinical experimental evidence, (R)-salbutamol has not shown consistent superiority over (S)- or racemic salbutamol in the treatment of patients with COPD.

(R)-salbutamol in the treatment of asthma and chronic obstructive airways disease

INTRODUCTION

Asthma and chronic obstructive pulmonary disease (COPD) are inflammatory disorders that have an increasing prevalence and associated morbidity and mortality. β(2)-adrenoceptor agonists (β(2)-agonists) act by stimulating the β(2)-adrenoceptor present on airway smooth muscle and other cells in the airway, resulting in bronchodilatation. β(2)-agonists are among the most commonly used drugs in the world and remain pivotal in the treatment of symptoms in patients with asthma and COPD. Salbutamol is a chiral drug with (R)- and (S)- isomers. Almost all β(2)-agonists that are used at present are racemic mixtures of (R)- and (S)-salbutamol.

AREAS COVERED

In this review the authors show that (R)-salbutamol alone (generically known as levosalbutamol) provides beneficial β(2)-agonist effects at a cellular level and in experimental models of airways disease. In addition the authors demonstrate that (S)-salbutamol opposes the desirable effects of (R)-salbutamol and can actually cause features of asthma and COPD in vitro and in experimental asthma.

EXPERT OPINION

Despite this strong body of experimental evidence, (R)-salbutamol has not shown consistent superiority over (S)- or racemic salbutamol in human asthma or COPD.

Development of liposomal salbutamol sulfate dry powder inhaler formulation

The purpose of our study was to develop a formulation of liposomal salbutamol sulfate (SBS) dry powder inhaler (DPI) for the treatment of asthma. Liposomes of high encapsulation efficiency (more than 80%) were prepared by a vesicular phospholipid gel (VPG) technique. SBS VPG liposomes were subjected to lyophilization using different kinds of cryoprotectants in various mass ratios. Coarse lactose (63-106 microm) in different mass ratios was used as a carrier. Magnesium stearate (0.5%) was added as a lubricator. The dry liposomal powders were then crushed by ball milling and sieved through a 400-mesh sieve to control the mean particle size at about 10 microm. The effects of different kinds of cryoprotectants and the amount of lactose carrier on the fine particle fraction (FPF) of SBS were investigated. The results showed that the developed formulation of liposomal dry powder inhaler was obtained using lactose as a cryoprotectant with a mass ratio of lyophilized powder to carrier lactose at 1 : 5; 0.5% magnesium stearate was used as a lubricator. The value of FPF for SBS was 41.51+/-2.22% for this formulation. Sustained release of SBS from the VPG liposomes was found in the in vitro release study. The study results offer the promising possibility of localized pulmonary liposomal SBS delivery in the anhydrous state.

Three generations of ongoing controversies concerning the use of short acting beta-agonist therapy in asthma: a review

An increase in asthma mortality in 1960s noted by British authors stirred a debate about the use of beta-adrenergic therapy that has persisted in the medical literature. The cause appears to be isoproterenol and fenoterol overuse. A second debate evolved around the possible deleterious, pro-inflammatory effects, of the albuterol distomer. Most clinical studies showed improved bronchodilatation, but limited benefits from using levalbuterol. Recently, genotyping has uncovered a single nucleotide polymorphism at codon 16 that appears to affect the long term response to both regular and as needed use of albuterol, calling for a new genotype based therapeutic approach in asthma.