Ambroxol for the prevention of chronic bronchitis exacerbations: long-term multicenter trial. Protective effect of ambroxol against winter semester exacerbations: a double-blind study versus placebo

Supramolecular Modulation of Antibacterial Activity of Ambroxol by Cucurbit[7]uril

Supramolecular encapsulation by cucurbit[7]uril (CB[7]) was recently demonstrated to provide a simple and efficient method for antibacterial activity regulation of antibiotics. In this work, CB[7] was shown to form binary host-guest complex with ambroxol hydrochloride (ABX), a clinical mucokinetic and expectorant drug, which was reported to exhibit certain antibacterial activity. ¹ H NMR titration and isothermal titration calorimetry experiment results suggested that the 4-hydroxyl cyclohexylamine group of ABX was included inside the CB[7] cavity, with a binding constant K_a of (6.69±0.11)×10⁵  M^-1 in phosphate buffered saline (PBS) solution, thermodynamically driven by both enthalpy change (ΔH=-12.2 kJ/mol) and entropy change (TΔS=21.1 kJ/mol). More importantly, ABX's inhibitory activity (MIC₅₀ ) against bacillary strains towards Pseudomonas aeruginosa and Escherichia coli strains was decreased from (5.11±0.31)×10^-6  M^-1 and (2.63±0.34)×10^-5  M^-1 to zero upon encapsulation by CB[7], and was subsequently recovered to almost its original activity when a competitive guest, amantadine hydrochloride, for disassembling CB[7]-ABX complex, was added, suggesting that the antibacterial activity of ABX could be readily "turned off/on" upon its complexation and decomplexation with CB[7].

Ambroxol Hydrochloride Inhibits the Interaction between Severe Acute Respiratory Syndrome Coronavirus 2 Spike Protein's Receptor Binding Domain and Recombinant Human ACE2

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), enters the host cells through two main pathways, both involving key interactions between viral envelope-anchored spike glycoprotein of the novel coronavirus and the host receptor, angiotensin-converting enzyme 2 (ACE2). To date, SARS-CoV-2 has infected up to 26 million people worldwide; yet, there is no clinically approved drug or vaccine available. Therefore, a rapid and coordinated effort to re-purpose clinically approved drugs that prevent or disrupt these critical entry pathways of SARS-CoV-2 spike glycoprotein interaction with human ACE2, could potentially accelerate the identification and clinical advancement of prophylactic and/or treatment options against COVID-19, thus providing possible countermeasures against viral entry, pathogenesis and survival. Herein, we discovered that Ambroxol hydrochloride (AMB), and its progenitor, Bromhexine hydrochloride (BHH), both clinically approved drugs are potent effective modulators of the key interaction between the receptor binding domain (RBD) of SARS-CoV-2 spike protein and human ACE2. We also found that both compounds inhibited SARS-CoV-2 infection-induced cytopathic effect at micromolar concentrations. Therefore, in addition to the known TMPRSS2 activity of BHH; we report for the first time that the BHH and AMB pharmacophore has the capacity to target and modulate yet another key protein-protein interaction essential for the two known SARS-CoV-2 entry pathways into host cells. Altogether, the potent efficacy, excellent safety and pharmacologic profile of both drugs along with their affordability and availability, makes them promising candidates for drug repurposing as possible prophylactic and/or treatment options against SARS-CoV-2 infection.

Pharmacokinetics of Ambroxol Sustained Release (Mucosolvan® Retard) Compared with Other Formulations in Healthy Volunteers

INTRODUCTION

Ambroxol is used in the treatment of acute and chronic respiratory conditions characterized by abnormal mucus secretion and impaired mucus transport and is available in a variety of formulations. This study aimed to compare the steady-state (SS) pharmacokinetic characteristics of extended-release (ER) 75-mg retard capsules with two immediate-release (IR) formulations (60-mg effervescent tablets and 30-mg tablets) over a 24-h period.

METHODS

An open-label, randomized, three-period, six-sequence crossover study was conducted in healthy volunteers aged 18-45 years who had a normal body mass index. The test (ER 75-mg retard capsule once daily) and reference treatments (half of IR 60-mg effervescent tablet twice daily or 30-mg IR tablet twice daily) were administered on days 1-5 of each treatment period. Meals were standardized and concomitant therapy was prohibited. Blood samples for pharmacokinetic assessment were collected on day 5 (SS) of each treatment period. The co-primary endpoints were exposure (AUCSS 0-24) and maximum plasma level (Cmax SS).

RESULTS

Twenty-four participants received ambroxol (male n = 13, 54.2%; mean ± standard deviation [SD] age 25.0 ± 6.4 years) and 23 completed the study. ER retard capsules provided similar AUCSS 0-24 compared to IR tablets (geometric means ratio [GMR] 110.7%; 90% confidence interval [CI] 99.8%, 122.7%) and effervescent tablets (GMR 106.9%; 90% CI 100.3%, 114.0%). ER retard capsules provided similar Cmax SS compared to IR tablets (GMR 84.7%, 90% CI 77.0%, 93.3%), and lower Cmax SS compared to effervescent tablets (GMR 80.9%, 90% CI 73.9%, 88.6%). Time to Cmax SS (tmax SS) was longer with ER retard capsules (6.0 h) than with IR tablets (2.0 h) or effervescent tablets (1.0 h).

CONCLUSIONS

ER ambroxol 75-mg retard capsules given once daily showed a similar pharmacokinetic profile to IR ambroxol formulations and therefore can be used instead of these in the treatment of respiratory conditions. CLINICALTRIALS.

GOV IDENTIFIER

NCT02036775.

Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume or purulence of sputum, or both. Personal and healthcare costs associated with exacerbations indicate that therapies that reduce the occurrence of exacerbations are likely to be useful. Mucolytics are oral medicines that are believed to increase expectoration of sputum by reducing its viscosity, thus making it easier to cough it up. Improved expectoration of sputum may lead to a reduction in exacerbations of COPD.

OBJECTIVES

Primary objective• To determine whether treatment with mucolytics reduces exacerbations and/or days of disability in patients with chronic bronchitis or COPDSecondary objectives• To assess whether mucolytics lead to improvement in lung function or quality of life• To determine frequency of adverse effects associated with use of mucolytics SEARCH METHODS: We searched the Cochrane Airways Group Specialised Register and reference lists of articles on 12 separate occasions, most recently on 23 April 2019.

SELECTION CRITERIA

We included randomised studies that compared oral mucolytic therapy versus placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

This review analysed summary data only, most derived from published studies. For earlier versions, one review author extracted data, which were rechecked in subsequent updates. In later versions, review authors double-checked extracted data and then entered data into RevMan 5.3 for analysis.

MAIN RESULTS

We added four studies for the 2019 update. The review now includes 38 trials, recruiting a total of 10,377 participants. Studies lasted between two months and three years and investigated a range of mucolytics, including N-acetylcysteine, carbocysteine, erdosteine, and ambroxol, given at least once daily. Many studies did not clearly describe allocation concealment, and we had concerns about blinding and high levels of attrition in some studies. The primary outcomes were exacerbations and number of days of disability.Results of 28 studies including 6723 participants show that receiving mucolytics may be more likely to be exacerbation-free during the study period compared to those given placebo (Peto odds ratio (OR) 1.73, 95% confidence interval (CI) 1.56 to 1.91; moderate-certainty evidence). However, more recent studies show less benefit of treatment than was reported in earlier studies in this review. The overall number needed to treat with mucolytics for an average of nine months to keep an additional participant free from exacerbations was eight (NNTB 8, 95% CI 7 to 10). High heterogeneity was noted for this outcome (I² = 62%), so results need to be interpreted with caution. The type or dose of mucolytic did not seem to alter the effect size, nor did the severity of COPD, including exacerbation history. Longer studies showed smaller effects of mucolytics than were reported in shorter studies.Mucolytic use was associated with a reduction of 0.43 days of disability per participant per month compared with use of placebo (95% CI -0.56 to -0.30; studies = 9; I² = 61%; moderate-certainty evidence). With mucolytics, the number of people with one or more hospitalisations was reduced, but study results were not consistent (Peto OR 0.68, 95% CI 0.52 to 0.89; participants = 1788; studies = 4; I² = 58%; moderate-certainty evidence). Investigators reported improved quality of life with mucolytics (mean difference (MD) -1.37, 95% CI -2.85 to 0.11; participants = 2721; studies = 7; I² = 64%; moderate-certainty evidence). However, the mean difference did not reach the minimal clinically important difference of -4 units, and the confidence interval includes no difference. Mucolytic treatment was associated with a possible reduction in adverse events (OR 0.84, 95% CI 0.74 to 0.94; participants = 7264; studies = 24; I² = 46%; moderate-certainty evidence), but the pooled effect includes no difference if a random-effects model is used. Several studies that could not be included in the meta-analysis reported high numbers of adverse events, up to a mean of five events per person during follow-up. There was no clear difference between mucolytics and placebo for mortality, but the confidence interval is too wide to confirm that treatment has no effect on mortality (Peto OR 0.98, 95% CI 0.51 to 1.87; participants = 3527; studies = 11; I² = 0%; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, we are moderately confident that treatment with mucolytics leads to a small reduction in the likelihood of having an acute exacerbation, in days of disability per month and possibly hospitalisations, but is not associated with an increase in adverse events. There appears to be limited impact on lung function or health-related quality of life. Results are too imprecise to be certain whether or not there is an effect on mortality. Our confidence in the results is reduced by high levels of heterogeneity in many of the outcomes and the fact that effects on exacerbations shown in early trials were larger than those reported by more recent studies. This may be a result of greater risk of selection or publication bias in earlier trials, thus benefits of treatment may not be as great as was suggested by previous evidence.

Safety of ambroxol in the treatment of airway diseases in adult patients

INTRODUCTION

Ambroxol is a widely used secretolytic and mucoactive over-the-counter agent primarily used to treat respiratory diseases associated with viscid mucus. Following post-marketing reports of hypersensitivity reactions and severe cutaneous adverse reactions (SCARs) possibly linked to ambroxol, the European Union's Pharmacovigilance Risk Assessment Committee (PRAC) initiated in April 2014 a review of the safety of ambroxol in all its registered indications, which was finalized in 2016. Areas covered: Here, we evaluate the clinical safety of ambroxol and provide an expert opinion on the benefit-risk balance of ambroxol in the treatment of adult patients with bronchopulmonary diseases. The evidence for this review is derived from clinical trials of ambroxol that were provided to the PRAC by the marketing authorization holders of ambroxol-containing medicines. Expert opinion: Clinical experience accumulated from randomized clinical trials and observational studies suggests that ambroxol is a safe and well-tolerated treatment of bronchopulmonary diseases, with a well-balanced and favorable benefit-risk profile. All reported adverse events were mild and self-limiting, and the risk of SCARs with ambroxol is low. Further investigations could address the safety and efficacy of ambroxol in pediatric lung diseases and in additional therapeutic indications, such as biofilm-dependent airway disease and lysosomal storage disorders.

Characterization of differential patient profiles and therapeutic responses of pharmacy customers for four ambroxol formulations

Background

Ambroxol relieves cough symptoms based on its secretagogue, anti-inflammatory, anti-oxidant, anti-bacterial, anti-viral, immunomodulatory and local anesthetic effects. The present study was designed to explore differential patient profiles and efficacy against acute respiratory symptoms of four formulations registered as over-the-counter medicines.

Methods

Nine hundred sixty-five pharmacy customers purchasing one of four branded ambroxol formulations (extended release capsules, adult syrup, pediatric syrup and soft pastilles) filled a questionnaire including a patient-adapted version of the Bronchitis Severity Scale, several questions on degree of impairment by acute cough, time to onset of symptom relief and duration of treatment. Data on pediatric syrup users were entered by their parents. Based on the exploratory character of the study, no hypothesis-testing statistical analysis was applied.

Results

Users of the pediatric syrup and the pastilles reported somewhat less severe baseline symptoms. The patient-adapted Bronchitis Severity Scale proved feasible as a self-administered tool. Among BSS items, ambroxol formulations improved chest pain while coughing to the largest and sputum to smallest degree (− 75% vs. -40%). Reported efficacy was comparable among formulations with minor differences in favor of the pediatric syrup. Time to onset of symptom relief was less than 60 min in more than 90% of patients and occurred prior to known systemic t_max. Time to onset was the parameter with the greatest differences between formulations, being reported fastest with pastilles and pediatric syrup and, as expected, slowest with extended release capsules. All ambroxol formulations were well tolerated.

Conclusions

We conclude that over-the-counter formulations of ambroxol exhibit comparable user profiles and efficacy. Differences in speed of onset of symptom relief may involve not only those in systemic pharmacokinetics but also local anesthetic effects of immediate release formulations. Differences between pediatric and adult syrup may in part reflect reporting bias.

[More than expectorant: new scientific data on ambroxol in the context of the treatment of bronchopulmonary diseases]

BACKGROUND

Ambroxol has been established for decades in the treatment of acute and chronic respiratory diseases. In 2015, the European Medicines Agency reassessed the clinical benefit-risk ratio of the drug.

OBJECTIVE

What new scientific data on ambroxol, which are relevant to the treatment of bronchopulmonary diseases, are available?

METHOD

The review is based on a systematic literature research in medline with the search term "ambroxol" during the publication period 2006-2015. Non-relevant publications were excluded manually.

RESULTS AND CONCLUSIONS

Ambroxol is still intensively researched. The traditional indication as an expectorant is confirmed. But there is also an ever better understanding of the various mechanisms of action as well as the ever more exact modeling of the structures under investigation. New fields of application are conceivable, e. g. in patients with severe pulmonary disease who undergo surgery or who are in intensive care, as an adjuvant in anti-infective therapies, especially in infections with biofilm-producing pathogens, or in rare diseases such as lysosomal storage diseases. However, final evidence of the clinical relevance in these fields of application is still missing.

Mucolytic Effectiveness of Tyloxapol in Chronic Obstructive Pulmonary Disease - A Double-Blind, Randomized Controlled Trial

Objective

Mucoactive drugs should increase the ability to expectorate sputum and, ideally, have anti-inflammatory properties. The aim of the study was to evaluate the mucolytic activity of Tyloxapol compared to saline (0.9%) in COPD.

Design

A randomized, placebo-controlled, double-blinded crossover, clinical trial was carried out. Patients were randomly assigned to either inhale 5 ml Tyloxapol 1% or saline 0.9% solution three times daily for 3 weeks and vice versa for another 3 weeks. 28 patients (18 male, 10 female, 47 to 73 years old, median age 63.50) were screened, 21 were treated and 19 patients completed the study per protocol.

Results

A comparison of the two treatment phases showed that the primary endpoint sputum weight was statistically significant higher when patients inhaled Tyloxapol (mean 4.03 g, 95% CI: 2.34–5.73 g at week 3) compared to saline (mean 2.63 g, 95% CI: 1.73–3.53 g at week 3). The p-value at three weeks of treatment was 0.041 between treatment arms. Sputum cells decreased during the Tyloxapol treatment after 3 weeks, indicating that Tyloxapol might have some anti-neutrophilic properties. Lung function parameters (FVC, FEV₁, RV, and RV/TLC) remained stable during the study, and no treatment effect was shown. Interestingly, there was a mean increase in all inflammatory cytokines (IL-1β, IL-6, and IL-8) during the saline treatment from day 1 to week 3, whereas during the Tyloxapol treatment, all cytokines decreased. Due to the small sample size and the large individual variation in sputum cytokines, these differences were not significant. However, analyses confirmed that Tyloxapol has significant anti-inflammatory properties in vitro. Despite the high number of inhalations (more than 1000), only 27 adverse events (20 during the Tyloxapol and seven during saline) were recorded. Eleven patients experienced AEs under Tyloxapol and six under saline treatment, which indicates that inhalation of saline or Tyloxapol is a very safe procedure.

Conclusion

Our study demonstrated that inhalation of Tyloxapol by patients with COPD is safe and superior to saline and has some anti-inflammatory effects.

Trial Registration

ClinicalTrials.gov NCT02515799

Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume or purulence of sputum, or both. Personal and healthcare costs associated with exacerbations indicate that any therapy that reduces the occurrence of exacerbations is useful. A marked difference among countries in terms of prescribing of mucolytics reflects variation in perceptions of their effectiveness.

OBJECTIVES

Primary objective• To determine whether treatment with mucolytics reduces frequency of exacerbations and/or days of disability in patients with chronic bronchitis or chronic obstructive pulmonary disease. Secondary objectives• To assess whether mucolytics lead to improvement in lung function or quality of life.• To determine frequency of adverse effects associated with use of mucolytics.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on 10 separate occasions, most recently in July 2014.

SELECTION CRITERIA

We included randomised studies that compared oral mucolytic therapy versus placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

This review analysed summary data only, most derived from published studies. For earlier versions, one review author extracted data, which were rechecked in subsequent updates. In later versions, review authors double-checked extracted data and then entered data into RevMan for analysis.

MAIN RESULTS

We added four studies for the 2014 update. The review now includes 34 trials, recruiting a total of 9367 participants. Many studies did not clearly describe allocation concealment; hence selection bias may have inflated the results, which reduces our confidence in the findings.Results of 26 studies with 6233 participants show that the likelihood that a patient could be exacerbation-free during the study period was greater among mucolytic groups (Peto odds ratio (OR) 1.75, 95% confidence interval (CI) 1.57 to 1.94). However, more recent studies show less benefit of treatment than was reported in earlier studies in this review. The overall number needed to treat with mucolytics for an additional beneficial outcome for an average of 10 months - to keep an additional participant free from exacerbations - was eight (NNTB 8, 95% CI 7 to 10). Use of mucolytics was associated with a reduction of 0.03 exacerbations per participant per month (mean difference (MD) -0.03, 95% CI -0.04 to -0.03; participants = 7164; studies = 28; I(2) = 85%) compared with placebo, that is, about 0.36 per year, or one exacerbation every three years. Very high heterogeneity was noted for this outcome, so results need to be interpreted with caution. The type or dose of mucolytic did not seem to alter the effect size, nor did the severity of COPD, including exacerbation history. Longer studies showed smaller effects of mucolytics than were reported in shorter studies.Mucolytic use was associated with a reduction of 0.43 days of disability per participant per month compared with placebo (95% CI -0.56 to -0.30; studies = 13; I(2) = 61%). With mucolytics, the number of people with one or more hospitalisations was reduced, but study results were not consistent (Peto OR 0.68, 95% CI 0.52 to 0.89; participants = 1788; studies = 4; I(2) = 58%). Investigators reported improved quality of life with mucolytics (MD -2.64, 95% CI -5.21 to -0.08; participants = 2231; studies = 5; I(2) = 51%). Although this mean difference did not reach the minimal clinically important difference of -4 units, we cannot assess the population impact, as we do not have the data needed to carry out a responder analysis. Mucolytic treatment was not associated with any significant increase in the total number of adverse effects, including mortality (Peto OR 1.03, 95% CI 0.52 to 2.03; participants = 2931; studies = 8; I(2) = 0%), but the confidence interval is too wide to confirm that the treatment has no effect on mortality.

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, we are moderately confident that treatment with mucolytics may produce a small reduction in acute exacerbations and a small effect on overall quality of life. Our confidence in the results is reduced by the fact that effects on exacerbations shown in early trials were larger than those reported by more recent studies, possibly because the earlier smaller trials were at greater risk of selection or publication bias, thus benefits of treatment may not be as great as was suggested by previous evidence.

Ambroxol inhibits rhinovirus infection in primary cultures of human tracheal epithelial cells

The mucolytic drug ambroxol hydrochloride reduces the production of pro-inflammatory cytokines and the frequency of exacerbation in patients with chronic obstructive pulmonary disease (COPD). However, the inhibitory effects of ambroxol on rhinovirus infection, the major cause of COPD exacerbations, have not been studied. We examined the effects of ambroxol on type 14 rhinovirus (RV14) infection, a major RV group, in primary cultures of human tracheal epithelial cells. RV14 infection increased virus titers and cytokine content in the supernatants and RV14 RNA in the cells. Ambroxol (100 nM) reduced RV14 titers and cytokine concentrations of interleukin (IL)-1β, IL-6 and IL-8 in the supernatants and RV14 RNA in the cells after RV14 infection, in addition to reducing susceptibility to RV14 infection. Ambroxol also reduced the expression of intercellular adhesion molecule-1 (ICAM-1), the receptor for RV14, and the number of acidic endosomes from which RV14 RNA enters the cytoplasm. In addition, ambroxol reduced the activation of the transcription factor nuclear factor kappa B (NF-κB) in the nucleus. These results suggest that ambroxol inhibits RV14 infection partly by reducing ICAM-1 and acidic endosomes via the inhibition of NF-κB activation. Ambroxol may modulate airway inflammation by reducing the production of cytokines in rhinovirus infection.

Ambroxol lozenge bioavailability : an open-label, two-way crossover study of the comparative bioavailability of ambroxol lozenges and commercial tablets in healthy thai volunteers

OBJECTIVE

To compare the bioavailability of two 15mg ambroxol lozenges with a commercial 30mg ambroxol tablet.

DESIGN

Open-label, two-way crossover study.

METHOD

Each formulation was randomly administered to 20 healthy Thai volunteers (ten male and ten female) with a 1-week washout period between formulations. After administration, serial blood samples were collected over a 24-hour period and the plasma concentration of ambroxol was subsequently measured using high performance liquid chromatography with ultraviolet detection after liquid-liquid extraction. Pharmacokinetic parameters were analysed by a noncompartmental pharmacokinetic model and compared between formulations using analysis of variance with a significance level of 0.05.

RESULTS

The point estimates (90% CI) of the area under the plasma concentration-time curve (AUC) and peak plasma concentration (C(max)) ratios between lozenge and commercial tablet were 1.07 (0.89 to 1.28) and 1.20 (1.04 to 1.40), respectively. The point estimate (90% CI) of the difference between formulations for time to C(max) was 0.40 (-0.20 to 1.00).

CONCLUSION

The two formulations under test were not bioequivalent based on the stipulated bioequivalence criteria. The bioavailability from the ambroxol lozenge might be better, since the 90% CI of the AUC(0-infinity) fell outside the bioequivalence range, and its range was narrower. The difference in rate of absorption was not conclusive because ambroxol was delivered from the lozenge by two parallel processes, namely absorption via oral and gastrointestinal mucosa. The additional oral mucosal absorption might not only contribute more absorption but also introduce variability compared with that of tablet administration. The relative importance of oral versus gastrointestinal mucosal absorption of ambroxol from the lozenge formulation, and the clinical significance of this, requires further study.

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume or purulence of sputum, or both. Because of the personal and healthcare costs associated with exacerbations, any therapy that reduces the number of exacerbations is useful. There is a marked difference among countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.

PRIMARY OBJECTIVE

to determine if treatment with mucolytics reduces the frequency of exacerbations, days of disability, or both, in participants with chronic bronchitis or chronic obstructive pulmonary disease, or both.

SECONDARY OBJECTIVES

to determine if mucolytics lead to an improvement in lung function or quality of life and to determine the frequency of adverse effects associated with mucolytics.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on ten separate occasions, the most recent being in July 2012.

SELECTION CRITERIA

We included randomised studies that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

The review analysed summary data only, the majority from published studies. For earlier versions, one author extracted data, which was rechecked in subsequent updates. In later versions, we double-checked data extraction. We then entered data into RevMan for analysis.

MAIN RESULTS

Two further trials have been added to the review for the 2012 update. There are now 30 trials in the review, recruiting a total of 7436 participants. Allocation concealment was not clearly described in the early trials, and selection bias may have inflated the results, which reduces our confidence in the findings of these trials.The likelihood of being exacerbation-free during the study period (22 trials in 4886 participants with a mean duration of 10 months) was greater in the mucolytic group for the double-blind trials (Peto odds ratio (OR) 1.84; 95% confidence interval (CI) 1.63 to 2.07). However, the more recent trials show less benefit of treatment than the earlier trials included in this review. The overall number needed to treat with mucolytics to keep an additional participant free from exacerbations over 10 months was seven (NNTB 7; 95% CI 6 to 9). The use of mucolytics was associated with a reduction of 0.04 exacerbations per participant per month (95% CI -0.04 to -0.03) compared with placebo; that is about 0.48 per year, or one exacerbation every two years. There was very high heterogeneity in this outcome (I(2) = 87%) so results need to be interpreted with caution.The number of days of disability per month also fell (mean difference (MD) -0.48; 95% CI -0.65 to -0.30) in 12 trials on 2305 participants. There was no clinically important improvement in lung function or consistent impact on quality of life with mucolytics. Mucolytic treatment was not associated with any significant increase in adverse effects, including mortality (Peto OR 0.75; 95% CI 0.35 to 1.64) in six trials on 1821 participants.

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, treatment with a mucolytic may produce a small reduction in acute exacerbations, but may have little or no effect on the overall quality of life. The effects on exacerbations shown in early trials were larger than those found in the more recent studies. This may be because the earlier smaller trials were at higher risk of selection or publication bias, so the benefits of treatment may not be as large as suggested by the previous evidence.

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume and/or purulence of sputum. Because of the personal and healthcare costs associated with exacerbations, any therapy that reduces the number of exacerbations is useful. There is a marked difference between countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.

OBJECTIVES

To assess the effects of oral mucolytics in adults with stable chronic bronchitis or COPD.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on eight separate occasions, the most recent being in September 2008.

SELECTION CRITERIA

Randomised trials that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

DATA COLLECTION AND ANALYSIS

One review author extracted data. We contacted study authors and drug companies for missing information.

MAIN RESULTS

Twenty-eight trials involving 7042 participants were included. Compared with placebo, there was a significant reduction in the number of exacerbations per patient with oral mucolytics (weighted mean difference (WMD) -0.04 per month, 95% confidence interval -0.05 to -0.03). Using a weighted annualised rate of exacerbations in the control patients of 2.4 per year, this is a 21% reduction. The number of days of disability also fell (WMD -0.56, 95% confidence interval (CI) -0.77 to -0.35). One recent study has shown that the benefit may apply only to patients not already receiving inhaled corticosteroids. The number of patients who remained exacerbation-free was greater in the mucolytic group (odds ratio (OR) 1.93 (95% CI 1.71 to 2.17)). There is no strong evidence of improvement in lung function and treatment is not associated with any increase in adverse effects. Patients on mucolytics may be less likely to be hospitalised during the study period.

AUTHORS' CONCLUSIONS

In participants with chronic bronchitis or COPD, treatment with mucolytics was associated with a small reduction in acute exacerbations and a reduction in total number of days of disability. Benefit may be greater in individuals who have frequent or prolonged exacerbations, or those who are repeatedly admitted to hospital with exacerbations with COPD. Mucolytics should be considered for use, through the winter months at least, in patients with moderate or severe COPD in whom inhaled corticosteroids (ICS) are not prescribed.

Action of N-acylated ambroxol derivatives on secretion of chloride ions in human airway epithelia

We report the effects of new N-acylated ambroxol derivatives (TEI-588a, TEI-588b, TEI-589a, TEI-589b, TEI-602a and TEI-602b: a, aromatic amine-acylated derivative; b, aliphatic amine-acylated derivative) induced from ambroxol (a mucolytic agent to treat human lung diseases) on Cl(-) secretion in human submucosal serous Calu-3 cells under a Na(+)/K(+)/2Cl(-) cotransporter-1 (NKCC1)-mediated hyper-secreting condition. TEI-589a, TEI-589b and TEI-602a diminished hyper-secretion of Cl(-) by diminishing the activity of NKCC1 without blockade of apical Cl(-) channel (TEI-589a>TEI-602a>TEI-589b), while any other tested compounds including ambroxol had no effects on Cl(-) secretion. These indicate that the inhibitory action of an aromatic amine-acylated derivative on Cl(-) secretion is stronger that that of an aliphatic amine-acylated derivative, and that 3-(2,5-dimethyl)furoyl group has a strong action in inhibition of Cl(-) secretion than cyclopropanoyl group. We here indicate that TEI-589a, TEI-589b and TEI-602a reduce hyper-secretion to an appropriate level in the airway, providing a possibility that the compound can be an effective drug in airway obstructive diseases including COPD by reducing the airway resistance under a hyper-secreting condition.

Ambroxol in the 21st century: pharmacological and clinical update

BACKGROUND

Belonging to the group of expectorants, ambroxol is an active substance with a long history that influences parameters considered to be the basis for the physiological production and the transport of the bronchial mucus. Therefore, ambroxol's indication is 'secretolytic therapy in acute and chronic bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport'.

OBJECTIVE

The aim of this review is to evaluate the pharmacological and clinical data on the mucokinetic compound ambroxol.

METHODS

The existing database that covers >40 years of pharmacological research and clinical development was analysed. Only studies with adequate study design were evaluated.

CONCLUSION

Ambroxol is shown to exert several activities: i) secretolytic activity (i.e., promotes mucus clearance, facilitates expectoration, and eases productive cough); ii) anti-inflammatory and antioxidant activity; and iii) a local anaesthetic effect through sodium channel blocking at the level of the cell membrane. The reduction on chronic obstructive pulmonary disease exacerbations is consistent and clinically relevant. The anaesthetic effect is a new pharmacological action that could be beneficial in the management of acute respiratory tract infections. The efficacy and safety of ambroxol is well established.

Development of the ambroxol gels for enhanced transdermal delivery

Ambroxol is an expectoration improver and mucolytic agent that has been used to treat acute and chronic disorders. However, ambroxol needs to be administered percutaneously in order to avoid systemic adverse effects, such as headache, drowsiness, dizziness, and insomnia, which can occur after oral administration. The aim of this study was to develop a gel preparation containing a permeation enhancer to enhance the delivery of ambroxol. The ambroxol gels were prepared using hydroxypropyl methylcellulose (HPMC) and poloxamer 407. The release characteristics of the drug from the gels were examined according to the receptor medium, drug concentration, and temperature. The rate of drug permeation into the skin was enhanced by incorporating various enhancers such as the ethylene glycols, the propylene glycols, the glycerides, the non-ionic surfactants, and the fatty acids into the gels. The permeation study through mouse skin was examined at 37 C. The rate of drug release increased with increasing drug concentration and temperature. Among the enhancers used, propylene glycol mono caprylate showed the best enhancing effects. The estimated activation energy of release (Ea), which was calculated from the slope of a log P versus 1000/T plot, was 14.80, 14.22, 13.91, and 12.46 kcal/mol for ambroxol loading doses of 2, 3, 4, and 5%, respectively. The results of this study show that the gel preparation of ambroxol containing a permeation enhancer could be developed for the enhanced transdermal delivery of ambroxol.

The role of airway secretions in COPD--clinical applications

It has been established that mucus hypersecretion and decreased mucus clearance contribute to the morbidity of chronic obstructive pulmonary disease (COPD). Indeed, the classic definition of chronic bronchitis relies on determining the frequency and duration of sputum expectoration. Despite the well recognized importance of this symptom, there are few therapies routinely used to decrease the sputum production or to improve clearance. There are fewer well conducted clinical trials of existing medications and this has led many regulatory agencies, notably the Food and Drug Administration (FDA), to refuse to register these medications or approve their sale. Similarly, airway clearance devices and chest physical therapy have not been well studied in COPD. Carefully conducted studies of interventions to improve airway clearance, similar to those done in cystic fibrosis (CF), may help us to identify effective therapies and possibly novel diagnostic tests for the management of COPD.

Nutritional supplements and infection in the elderly: why do the findings conflict?

Background

Most of the randomized placebo-controlled trials that have examined the clinical effects of multivitamin-mineral supplements on infection in the elderly have shown no significant effect. The exceptions are three such trials, all using a supplement with the same composition, and all claiming dramatic benefits: a frequently cited study published in 1992, which reported a 50% reduction in the number of days of infection (NDI), and two 2002 replication studies. Questions have been raised about the 1992 report; a second report in 2001 based on the same trial, but describing effects of the supplement on cognitive functions, has been retracted by Nutrition. The primary purpose of the present paper is to evaluate the claims about the effects of supplements on NDI in the two replication reports.

Methods

Examination of internal consistency (outcomes of statistical tests versus reported data); comparison of variability of NDI across individuals in these two reports with variability in other trials; estimation of the probability of achieving the reported close agreement with the original finding.

Results

The standard deviations of NDI and levels of statistical significance reported are profoundly inconsistent. The reported standard deviations of NDI are consistently below what other studies have found. The reported percent reductions in NDI agree too closely with the original study.

Conclusion

The claims of reduced NDI in the two replication reports should be questioned, which also adds to concerns about the 1992 study. It follows that there is currently no trustworthy evidence from randomized placebo-controlled clinical trials that favors the use of vitamin-mineral supplements to reduce infection in the elderly.

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume and/or purulence of sputum. Because of the personal and healthcare costs associated with exacerbations, any therapy that reduces the number of exacerbations is useful. There is a marked difference between countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.

OBJECTIVES

To assess the effects of oral mucolytics in adults with stable chronic bronchitis or COPD.

SEARCH STRATEGY

We have searched the Cochrane Airways Group Specialised Register and reference lists of articles on four separate occasions, the most recent being in June 2005. This is the third major update.

SELECTION CRITERIA

Randomised trials that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. Studies of people with asthma and cystic fibrosis were excluded.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data. Study authors and drug companies were contacted for missing information.

MAIN RESULTS

Twenty six trials were included (7335 participants). Compared with placebo, there was a significant reduction in the number of exacerbations per patient with oral mucolytics (weighted mean difference (WMD) -0.05 per month, 95% confidence interval -0.05, -0.04). Using the annualised rate of exacerbations in the control patients of 2.6 per year, this is a 20% reduction. The number of days of disability also fell (WMD -0.56, 95% confidence interval -0.77, -0.35). A recent study has shown that the benefit may apply only to those patients not already receiving inhaled corticosteroids. The number of patients who remained exacerbation-free was greater in the mucolytic group (OR 2.13 (95% CI 1.86 to 2.42)). There was no difference in lung function or in adverse effects reported between the treatments.

AUTHORS' CONCLUSIONS

In subjects with chronic bronchitis or COPD, treatment with mucolytics was associated with a small reduction in acute exacerbations and a reduction in total number of days of disability. Benefit may be greater in individuals who have frequent or prolonged exacerbations, or those who are repeatedly admitted to hospital with exacerbations with COPD. They should be considered for use, through the winter months at least, in patients with moderate or severe COPD in whom inhaled corticosteroids (ICS) are not prescribed.

Ambroxol-induced modification of ion transport in human airway Calu-3 epithelia

Ambroxol is often used as a mucolytic agent in various lung diseases. However, it is unclear how ambroxol acts on bronchial epithelial cells. To clarify the action of ambroxol, we studied the effects of ambroxol on the ion transport in human Calu-3 cells, a human submucosal serous cell line, measuring the transepithelial short-circuit current and conductance across monolayers of Calu-3 cells. Ambroxol of 100 microM diminished the terbutaline (a beta2-adrenergic agonist)-stimulated Cl-/HCO3(-)-dependent secretion without any decreases in the conductance of cystic fibrosis transmembrane conductance regulator (CFTR) channel locating on the apical membrane. On the other hand, under the basal (unstimulated) condition ambroxol increased the Cl(-)-dependent secretion with no significant change in the apical CFTR channel conductance and decreased the HCO3- secretion associated with a decrease in the apical CFTR channel conductance. Ambroxol had no major action on the epithelial Na+ channel (ENaC) or the ENaC-mediated Na+ absorption. These results indicate that in Calu-3 cells: (1) under the basal (unstimulated) condition ambroxol increases Cl- secretion by stimulating the entry step of Cl- and decreases HCO3- secretion by diminishing the activity of the CFTR channel and/or the Na+/HCO3(-)-dependent cotransporter, (2) under the adrenergic agonist-stimulated condition, ambroxol decreases Cl- secretion by acting on the Cl-/HCO3- exchanger, and (3) ambroxol has a more powerful action than the adrenergic agonist on the Cl-/HCO3- exchanger, leading fluid secretion to a moderately stimulated level from a hyper-stimulated level.

Effect of twelve-months therapy with oral ambroxol in preventing exacerbations in patients with COPD. Double-blind, randomized, multicenter, placebo-controlled study (the AMETHIST Trial)

The objective of this prospective, randomized, double-blind, placebo-controlled, multicenter parallel-group study was to evaluate the effect of long-term ambroxol treatment in preventing exacerbations of chronic obstructive pulmonary disease (COPD). Two hundred and forty-two outpatients with COPD defined by ATS criteria with value of FEV1 between > or =60 and 80% of predicted and history of one or more exacerbations in the previous year were recruited by 26 Respiratory Medicine Centers in Italy and treated for 1 year with one ambroxol retard capsule of 75 mg twice daily or placebo. The percentage of patients free from exacerbation at 6 months was 63% with ambroxol and 60% with placebo (p=0.366) and at 12 months 56% with ambroxol and 53% with placebo (p=0.363). In a subset of 45 patients with more severe baseline symptoms, ambroxol therapy was associated with a significant higher percentage of patients free from exacerbation compared to placebo: 63 vs. 38% (p=0.038). In conclusion, we did not find a significant difference between long-term ambroxol therapy and placebo, in preventing exacerbations in patients with COPD. In patients with more severe respiratory symptoms at baseline, however, we observed a significant difference in the cumulative exacerbation-free persistence between ambroxol and placebo, suggesting that long-term muco-regulatory therapy with ambroxol could be useful in highly symptomatic patients with COPD.

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

BACKGROUND

Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume and/or purulence of sputum and any therapy that reduced the number of exacerbations would be useful. There is a marked difference between countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.

OBJECTIVES

To assess the effects of oral mucolytics in adults with stable chronic bronchitis or COPD.

SEARCH STRATEGY

We have searched the Cochrane Airways Group trials register and reference lists of articles, on three separate occasions.

SELECTION CRITERIA

Randomised trials that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. Studies of people with asthma and cystic fibrosis were excluded.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data. Study authors and drug companies were contacted for missing information.

MAIN RESULTS

Twenty three trials were included. Compared with placebo, there was a significant reduction in the number of exacerbations per patient with oral mucolytics (weighted mean difference (WMD) -0.066 per month, 95% confidence interval -0.077, -0.054, p<0.001). Using the annualised rate of exacerbations in the control patients of 2.7 per year, this is a 29% reduction. The number of days of disability also fell (WMD -0.56, 95% confidence interval -0.77, -0.35, p<0.001). The number of patients who remained exacerbation-free was greater in the mucolytic group (OR 2.22, 95% confidence interval 1.93, 2.54, p<0.001). There was no difference in lung function or in adverse effects reported between treatments.

REVIEWER'S CONCLUSIONS

In subjects with chronic bronchitis or COPD, treatment with mucolytics was associated with a small reduction in acute exacerbations and a somewhat greater reduction in total number of days of disability.

Oral mucolytic drugs for exacerbations of chronic obstructive pulmonary disease: systematic review

OBJECTIVE

To assess the effects of oral mucolytics in adults with stable chronic bronchitis and chronic obstructive pulmonary disease.

DESIGN

Systematic review of randomised controlled trials that compared at least two months of regular oral mucolytic drugs with placebo.

STUDIES

Twenty three randomised controlled trials in outpatients in Europe and United States.

MAIN OUTCOME MEASURES

Exacerbations, days of illness, lung function, adverse events.

RESULTS

Compared with placebo, the number of exacerbations was significantly reduced in subjects taking oral mucolytics (weighted mean difference -0.07 per month, 95% confidence interval -0.08 to -0.05, P<0.0001). Based on the annualised rate of exacerbations in the control subjects of 2.7 a year, this is a 29% reduction. The number needed to treat for one subject to have no exacerbation in the study period would be 6. Days of illness also fell (weighted mean difference -0.56, -0.77 to -0.35, P<0.0001). The number of subjects who had no exacerbations in the study period was greater in the mucolytic group (odds ratio 2.22, 95% confidence interval 1.93 to 2.54, P<0.0001). There was no difference in lung function or in adverse events reported between treatments.

CONCLUSIONS

In chronic bronchitis and chronic obstructive pulmonary disease, treatment with mucolytics is associated with a reduction in acute exacerbations and days of illness. As these drugs have to be taken long term, they could be most useful in patients who have repeated, prolonged, or severe exacerbations of chronic obstructive pulmonary disease.

Modulating effects of mucoregulating drugs on the attachment of Haemophilus influenzae

Non-typable Haemophilus influenzae (NTHI) is one of the three major pathogens implicated in human respiratory infections. The ability to attach with pharyngeal epithelial cells is an important factor for infection and virulence. In the present study we describe the effects of two mucoregulating drugs, S-carboxymethylcysteine (S-CMC) and ambroxol, on the attachment of NTHI to pharyngeal epithelial cells. There was a significant (P < 0.0001, < 0.001 and <0.01) decrease of attachment (8.8 +/ 2.4, 9.2+/-2.5 and 15.4 +/- 5.7 bactreria/cell) compared with the control (17.5 +/- 2.9, 15.5 +/- 3.1 and 18.8 +/- 6.8 bacteria/cell) after cells were treated wth S-CMC at a dose of 100, 10 and 1 microg/ml. After attachment assay, cells treated with S-CMC (100 microg/ml) showed a significant decrease (P < 0.01) of attached bacteria (3.1 +/- 0.8 bacteria/cell) compared with the control (5.9 +/- 1.8 bacteria/cell). Treatment of cells with ambroxol did not influence bacterial attachment. By scanning electron microscopic observation it was found that NTHI attaches to the surface elevations (microplicae) of human pharyngeal epithelial cells. Atomic force microscopic observation revealed that the surface potential of microplicae decreased significantly in cells treated with S-CMC compared with the untreated control cells. As bacteria with negative surface charge attach to the positively charged domain, i.e. microplicae of human pharyngeal epithelial cells, this study suggests that the decrease of attachment of NTHI with epithelial cells after treatment with S-CMC was possibly due to the decrease of surface charge. This study suggests that S-CMC decreases the episodes of respiratory infections in patients with respiratory diseases both by inhibiting the attachment of bacteria to the upper respiratory tract, and by detaching the adherent one.

Treatment of idiopathic bronchiectasis with aerosolized recombinant human DNase I. rhDNase Study Group

STUDY OBJECTIVE

To study the safety and efficacy of aerosolized recombinant human DNase I in the treatment of idiopathic bronchiectasis.

DESIGN

Double-blind, randomized, placebo-controlled, multicenter study.

POPULATIONS

Three hundred forty-nine adult outpatients in stable condition with idiopathic bronchiectasis from 23 centers in North America, Great Britain, and Ireland.

INTERVENTIONS AND MEASUREMENTS

Study patients received aerosolized rhDNase or placebo twice daily for 24 weeks. Primary end points were incidence of pulmonary exacerbations and mean percent change in FEV1 from baseline over the treatment period.

RESULTS

Pulmonary exacerbations were more frequent and FEV1 decline was greater in patients who received rhDNase compared with placebo during this 24-week trial.

CONCLUSIONS

rhDNase was ineffective and potentially harmful in this group of adult outpatients in stable condition with idiopathic bronchiectasis. This contrasts with previously published results that demonstrated efficacy of rhDNase in patients with cystic fibrosis bronchiectasis.

Characterization of N-acetylcysteine and ambroxol in anti-oxidant therapy

Reactive free oxygen radicals are known to play an important role in the pathogenesis of various lung diseases such as idiopathic pulmonary fibrosis (IPF), adult respiratory distress syndrome (ARDS) or cystic fibrosis (CF). They can originate from endogenous processes or can be part of exogenous exposures (e.g. ozone, cigarette smoke, asbestos fibres). Consequently, therapeutic enhancement of anti-oxidant defence mechanisms in these lung disorders seems a rational approach. In this regard, N-acetyl-L-cysteine (NAC) and ambroxol have both been frequently investigated. Because of its SH group, NAC scavenges H2O2 (hydrogen peroxide), .OH (hydroxol radical), and HOCl (hypochlorous acid). Furthermore, NAC can easily be deacetylated to cysteine, an important precursor of cellular glutathione synthesis, and thus stimulate the cellular glutathione system. This is most evident in pulmonary diseases characterized by low glutathione levels and high oxidant production by inflammatory cells (e.g. in IPF and ARDS). NAC is an effective drug in the treatment of paracetamol intoxication and may even be protective against side-effects of mutagenic agents. In addition NAC reduces cellular production of pro-inflammatory mediators (e.g. TNF-alpha, IL-1). Also, ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexane hydrochloride] scavenges oxidants (e.g. .OH, HOCl). Moreover, ambroxol reduces bronchial hyperreactivity, and it is known to stimulate cellular surfactant production. In addition, ambroxol has anti-inflammatory properties owing to its inhibitory effect on the production of cellular cytokines and arachidonic acid metabolites. For both substances effective anti-oxidant and anti-inflammatory function has been validated when used in micromolar concentrations. These levels are attainable in vivo in humans. This paper gives an up-to-date overview about the current knowledge of the hypothesis that oxidant-induced cellular damage underlies the pathogenesis of many human pulmonary diseases, and it discusses the feasibility of anti-oxidant augmentation therapy to the lung by using NAC or ambroxol.

Ambroxol inhibits doxorubicin-induced lipid peroxidation in heart of mice

A single intravenous injection of doxorubicin (DOX, 30 mg/kg body weight) caused a significant rise in the content of lipid peroxidation products in hearts of mice. The concentration of conjugated dienes (CD) and malondialdehyde (MDA) found 24 h after injection of DOX increased about 1.8- and 2.4-fold and reached values of 11.31 +/- 2.24 A233/g and 3.72 +/- 0.40 mumol/g, respectively. The same dose of 4'-epi-doxorubicin (EPI), a less cardiotoxic epimer of DOX, increased only the heart level of MDA. Both antracyclines were not able to induce increased formation of CD in murine liver and lungs. Ambroxol, an expectorant drug which possesses the ability to scavenge hydroxyl radicals, injected intravenously (70 mg/kg) 30 min prior to DOX, completely abolished the rise in heart content of CD and MDA. The heart levels of CD and MDA in animals treated with ambroxol and DOX were 3 and 2.7 times lower than those observed in mice treated with water and DOX, respectively. Ambroxol had no effect on DOX- and EPI-induced formation of MDA in the lungs. Our results indicate that (1) DOX is a more powerful inductor lipid peroxidation in the heart than EPI; and (2) ambroxol may be useful in preventing lipid peroxidation in the heart caused by DOX.

Antioxidant properties of Ambroxol

We tested whether Ambroxol, a drug which stimulates the release of surfactant by pneumocytes type II, may also possess antioxidant properties. To assess the reactivity of Ambroxol with reactive oxygen species, we analysed its ability to decompose hydrogen peroxide (H2O2) and to inhibit the superoxide (O2.-)-dependent autooxidation of pyrogallol, hydroxyl radical (.OH)-mediated deoxyribose oxidation, and hypochlorous acid (HClO-induced chlorination of monochlorodimedon. Ambroxol was found to be a sufficient scavenger of HClO and .OH and also revealed the capacity to decompose H2O2. At concentrations of 25 and 70 microM, it inhibited HClO-induced chlorination of monochlorodimedon by 22 +/- 13 and 59 +/- 14%, respectively. Similarly, at concentrations of 1, 2, and 10 mM, Ambroxol decreased .OH-mediated deoxyribose oxidation by 47 +/- 11, 75 +/- 9, and 89 +/- 4%. In addition, at concentrations of 1 to 5 mM, it completely protected linoleic acid from .OH-induced peroxidative damage. Ambroxol had a weak effect on O2.(-)-dependent autooxidation of pyrogallol. Our results indicate that Ambroxol has antioxidant activity, which may have clinical significance in protecting lung tissue from oxidant-induced injury.