Nebulised bronchodilators, corticosteroids, and rhDNase in adult patients with cystic fibrosis

Asthma in Cystic Fibrosis: Definitions and Implications of This Overlap Syndrome

PURPOSE OF REVIEW

Cystic fibrosis (CF) is a multisystem, autosomal recessive disease that leads to progressive loss of lung function. Respiratory symptoms for both CF and asthma include cough, wheezing, and dyspnea. There is debate within the CF community on how to best define and distinguish CF-asthma overlap syndrome (CFAOS) from asthma-like features, though CFAOS is well-recognized. We aim to review the epidemiology, diagnosis, and treatment of asthma in CF and explore areas where further research is needed.

RECENT FINDINGS

There has been considerable improvement in the understanding and treatment of asthma over the past two decades leading to novel therapies such as biologic agents that target the airway inflammation in asthmatics based on their asthma phenotype. These therapies are being studied in CFAOS and are promising treatments. This review provides a comprehensive overview of the definition, epidemiology, diagnosis, and current treatment of CFAOS.

Effect of Excipients on the Stability and Aerosol Performance of Nebulized Aviscumine

Pulmonary delivery is an attractive alternative route to deliver protein drugs that are currently delivered by injection. Inhalation therapy via nebulizers is a well accepted way for pulmonary application of proteins considering the formulation difficulties of MDIs or DPIs. This research presents the effect of variable excipients on the stability and aerosol performance of freeze-dried aviscumine after reconstitution and nebulization. Aviscumine formulations containing 100 mmol/L Tris buffer, 0.1% (w/v) Polysorbate 80, 0.01% (w/v) Na(2)-EDTA and 8% (w/v) Hydroxyethyl starch have been lyophilized and reconstituted with a buffered isotonic solution pH 8. The aviscumine activity was determined by a binding assay directly after reconstitution and after nebulization with a PariBoy air-jet nebulizer, a Multisonic and a Systam ultrasonic nebulizer. The stabilization of aviscumine by the addition of variable buffer salts to the reconstitution medium, such as 50, 100, and 200 mmol/L Tris buffer, 20 and 100 mmol/L phosphate buffer, and 20 and 100 mmol/L Tricine buffer, was studied. About 50% of aviscumine activity was lost after 20 min nebulization time without any additives. Nevertheless, higher buffer concentrations confer greater stability. About 70% of the aviscumine activity could be retained by the addition 0.03% octanoyl-N-methylglucamide and 100 mmol/L Tricine to the reconstitution medium.

Bronchiectasis in secondary care: a comprehensive profile of a neglected disease

Background: Bronchiectasis is poorly characterised in secondary care. Methods: Over 6 months, 410 bronchiectasis patients attended our clinics. One hundred randomly selected patients were characterised in detail. Results: Patients had a mean and standard error of mean (S.E.M.) age of 57 (2) years and a median and interquartile range (IQR) of three (two to four) reviews in the last 12 months. Aetiologies identified included tuberculosis (n=15), childhood pneumonia (n=7), fibrosis (n=6), connective tissue disease (n=6), whooping cough (n=5), childhood measles (n=4) and others (n=5). There was widespread use of inhaled therapy. Treatments included oral antibiotics (n=77), corticosteroid courses (n=27) and intravenous antimicrobials (n=27, 12 domicillary) in the last year. Thirty patients had hospital admissions (13 because of the inability to administer domicillary antibiotics). Haemophilus influenzae and Pseudomonas spp. were the commonest bacterial isolates. Patients culturing Pseudomonas spp. were older and had had more reviews and intravenous antibiotic courses. Conclusions: Bronchiectasis imposes a considerable burden on hospital services. Patients culturing Pseudomonas spp. impose a greater burden. Aetiology is often unknown. Therapies with unproven benefit are often used.

Effect of cryoprotectants on the stability and aerosol performance of nebulized aviscumine, a 57-kDa protein

Nebulization of aqueous drug solutions is a suitable delivery system for pulmonary application of proteins because it can easily produce droplets small enough to reach the alveolar region. However, proteins are sensitive to nebulization. Therefore, stabilizers need to be added which on the other hand influence the aerosol performance, such as average droplet size or mass output. This research presents the effect of various cryoprotectants such as Na-polyphosphate, CaCl(2) x 6H(2)O and MgSO(4) x 7H(2)O on the stability and aerosol performance of freeze-dried aviscumine after reconstitution and nebulization using three different nebulizers. Formulations containing Tris-buffer, polysorbate 80, Na(2)-EDTA and HES450 were lyophilized and reconstituted with a buffered isotonic solution containing 100 mmol/l Tricine-buffer pH 8, 0.03% (w/v) octanoyl-N-methylglucamide, 150 mmol/l NaCl and a cryoprotectant. The aviscumine activity was determined by a binding assay. The addition of 0.2% Na-polyphosphate to the reconstitution medium led to retention of approx. 73% of the aviscumine activity after 20 min nebulization with the Systam ultrasonic nebulizer. It has been observed that 84 and 72% of the activity were retained by the addition of 10 mmol/l CaCl(2) x 6H(2)O using PariBoy air-jet and Multisonic ultrasonic nebulizer, respectively. In addition, a decrease in the mean droplet size with increasing the cryoprotectant concentration has been observed. A relationship between the average droplet size, surface tension and viscosity depending on the used cryoprotectant type and concentration could be established.

The effect of formulation variables on the stability of nebulized aviscumine

The pulmonary drug delivery of proteins present an alternative to parenteral and oral administration. Nebulization of aqueous protein solutions is an ideal method for pulmonary application of therapeutic proteins considering the difficulties of their formulation as MDIs or DPIs. This research presents the effect of variable excipients on the stability of freeze-dried aviscumine after reconstitution and nebulization. Formulations containing different lyoprotectants have been lyophilized and reconstituted with isotonic salt solution. The loss of aviscumine activity in the nebulizer reservoir and after nebulization with a PariBoy air-jet nebulizer, a Multisonic ultrasonic nebulizer and a Systam ultrasonic nebulizer was determined by a binding assay. The effect of variable lyoprotectants such as 8% (w/v) Dextran T1, HES130, HES450, HP-beta-CD and 6% (w/v) HES450 plus 2% (w/v) mannitol on the stability of aviscumine to air-jet and ultrasonic nebulization has been evaluated. Only 50% of aviscumine activity was retained after 20 min nebulization, where 8% (w/v) HES450 was shown to be the best stabilizer. Stabilization of aviscumine by the addition of variable surfactants as 0.01 and 0.1% (w/v) Poloxamer 188, 0.03 and 0.1% (w/v) PEG 8000, 0.03 and 0.1% (w/v) Solutol HS15 and 0.03 and 0.1% (w/v) octanoyl-N-methyl-glucamide to the reconstitution solution has also been studied. By the addition of 0.03% (w/v) octanoyl-N-methyl-glucamide, 70% of the activity was retained after 20 min nebulization.

"CF asthma": what is it and what do we do about it?

The diagnosis of "CF asthma" is problematic and it is difficult to determine which patients have a combination of CF and asthma and which have asthma like symptoms caused by inflammation of the CF lung. This may not matter, however; the relevance lies in the possible approaches to treatment.

Increased nitrotyrosine in exhaled breath condensate in cystic fibrosis

Exhaled nitric oxide (ENO), a marker of inflammation in airway diseases is decreased in cystic fibrosis (CF) patients, perhaps because nitric oxide (NO) is metabolized to oxidative end-products. A stable product, 3-nitrotyrosine, may indicate local formation of reactive nitrogen species. Whether NO metabolites in exhaled breath condensate may be increased in CF patients was investigated. The fractional concentration of ENO (Feno), nitrotyrosine and oxides of nitrogen in exhaled breath condensate from 36 stable CF patients were compared to 14 normal subjects using an enzyme immunoassay and fluorescence assay. Nitrotyrosine levels in breath condensate were increased significantly in stable CF patients, compared with normal subjects (25.3 +/- 1.5 versus 6.3 +/- 0.8 ng x mL(-1), p<0.0001). There was an inverse correlation between the levels of nitrotyrosine and the severity of lung disease. Feno levels were significantly lower in CF patients than in normal subjects (4.4 +/- 0.3 versus 5.6 +/- 0.4 (parts per billion), p<0.05). No correlation was found between nitrotyrosine and Feno levels in CF. There was no significant difference in the levels of nitrite and nitrate between CF patients and normals. The elevation in nitrotyrosine may reflect increased formation of reactive nitrogen species such as peroxynitrite or direct nitration by granulocyte peroxidases, indicating increased oxidative stress in airways of cystic fibrosis patients.