Improvement of pressurised aerosol deposition with Nebuhaler spacer device

Influence of respiratory spacer devices on aerodynamic particle size distribution and fine particle mass of beclomethasone from metered-dose inhalers

Respiratory spacer devices are used mainly with pressurized metered dose inhalers, especially those containing corticosteroids, to assist with patient coordination and reduce oropharyngeal side effects. This investigation examines the influence of different spacer devices on the delivered fine particle mass (aerodynamic diameter of <3.3 microm and <4.7 microm) of the corticosteroid beclomethasone dipropionate, which approximates the respirable dose. The Anderson Mark II Cascade Impactor was used to characterise the deposition of single doses of beclomethasone dipropionate from several metered-dose inhalers. Following actuation of one single dose the amount of beclomethasone dipropionate deposited on each stage of the impactor was quantified using reverse phase high-performance liquid chromatography and ultraviolet detection. The fine particle mass smaller than 4.7 microm for Respocort delivered by the Sanner and Fisonair spacer devices was 77.7% and 41.3% higher (p < 0.04), respectively, than the metered-dose inhaler alone, while the Breathatech spacer delivered 21.4% lower (p < 0.01). The fine particle mass of Becotide delivered by the Sanner, Fisonair, Nebuhaler, and Volumatic spacer devices were 81%, 42.4%, 46.9%, and 32.8% higher (p < 0.008), respectively, than be metered dose inhaler alone. The fine particle mass for Becloforte delivered by the Sanner, Fisonair, and Volumatic spacer devices was 82.8%, 36.9%, and 48.0% higher (p < 0.009) than that delivered by metered dose inhaler alone. This study suggests that there are significant differences in the fine particle mass of beclomethasone dipropionate delivered by respiratory spacer devices when used in conjunction with commercially available metered dose inhalers of this drug.

Metering performance of several metered-dose inhalers with different spacers/holding chambers

Metered-dose inhalers (MDI) are routinely used to administer inhaled antiasthma drugs. Actuation-inhalation coordination problems are overcome and systemic side effects are reduced by using spacers/holding chambers (SP/HCHs). Many of these devices do not allow the use of the manufacturer's actuator. The objectives of this study were (a) to investigate the effect of the interaction of eight MDI products with four different SP/HCHs on their metering performance (MP); and (b) to test the hypothesis whether the MP obtained with a SP/HCH and a given drug (MDI) can be extrapolated to other MDIs, even for members of its particular drug class. The procedure outlined in The United States Pharmacopeia-The National Formulary was used (determination of canister weight changes after actuation). The SP/HCH tested were Aerochamber, Inspirease, and ACE. The MDIs tested were salmeterol xinafoate; albuterol with chlorofluorocarbons and 1,1,1,2-tetrafluoroethane as propellants; cromolyn sodium; nedocromil sodium; flunisolide; beclomethasone dipropionate; and fluticasone propionate. Only flunisolide-Inspirease presented an unacceptable MP. Although within the acceptable limits, the MP varied significantly between the following MDI-SP/HCH combinations: Optihaler-fluticasone propionate and Optihaler-cromolyn sodium < to Aerochamber-fluticasone propionate and Aerochamber-cromolyn sodium (p = 0.0015 and p = 0.0007, respectively); and Inspirease-flunisolide and Optihaler-flunisolide < Aerochamber flunisolide (p = 0.003 and p = 0.005, respectively). MP did not significantly vary when albuterol with chlorofluorocarbons or 1,1,1,2-tetrafluoroethane as propellants, salmeterol xinafoate, beclomethasone dipropionate, and nedocromil sodium were attached to any of the SP/HCHs studied. Our results emphasize the capital importance of choosing the right combination of MDI and SP/HCH for aerosol delivery. The MP obtained with a drug and a SP/HCH cannot be expected to be similar for other MDIs, even for members of its drug class. These data also suggest the need for regulatory agencies to approve an MDI to be used only with the SP/HCHs tested.

Single-dose study to compare the pharmacokinetics of HFA flunisolide and CFC flunisolide

The hydrofluoroalkane (HFA) formulation of the inhaled corticosteroid flunisolide is a modification of the original chlorofluorocarbon (CFC) formulation. HFA flunisolide replaces CFC with an HFA propellant and uses a built-in spacer in its pressurized metered-dose inhaler. The average HFA flunisolide particle size is 1.2 microm compared with 3.8 microm for the CFC formulation. The smaller particle size improves lung targeting, allowing a reduction in the HFA flunisolide dose relative to CFC flunisolide while maintaining comparable efficacy. In a study of 12 healthy men, pharmacokinetic parameters were determined after single doses of 1000 microg CFC flunisolide delivered without a spacer, 340 microg HFA flunisolide delivered through a spacer, and 516 microg HFA flunisolide delivered without a spacer. A standard noncompartmental analysis of the concentration data was performed and mean (+/- S.D.) pharmacokinetic values were reported. Peak plasma concentrations (observed C(max)) were similar for the three treatments. Area under the curve up to the time corresponding to the last measurable concentration (AUC(0)(-)(tlast)) was similar for the CFC and HFA flunisolide, plus spacer groups (4.4 +/- 1.6 ng x h/mL and 5.0+/- 4.2 ng x h/mL, respectively); however, AUC(0)(-)(tlast) for the HFA flunisolide without spacer group was comparatively lower than for the CFC group (3.5 +/- 1.6 ng x h/mL). Observed C(max) and AUC(0)(-)(tlast) for 6 beta-OH flunisolide, the first-pass metabolite of flunisolide and an indicator of oropharyngeal deposition, were significantly higher in the CFC flunisolide group than in either HFA flunisolide group.

Asthma medications and their potential adverse effects in the elderly: recommendations for prescribing

The incidence of drug-induced adverse effects is likely to increase as a result of advanced age and exposure of elderly patients to polypharmacy. Therefore, pharmacological therapy of asthma and chronic obstructive pulmonary disease (COPD) in the elderly patient can be potentially hazardous. beta(2)-agonists, administered as therapy for asthma and COPD, have recognised systemic sequelae, such as hypokalaemia and chronotropic effects, which may be life-threatening in susceptible patients. Adverse effects such as hypokalaemia can be aggravated by concomitant treatment with other drugs promoting potassium loss including diuretics, corticosteroids and theophyllines. In addition, relatively minor adverse events associated with the administration of beta(2)-agonists, such as tremor and blood pressure changes, may be of significance to the elderly patient leading to impairment in the quality of life. However, long-term treatment with beta(2)-agonists may reduce the incidence of drug-induced adverse effects as a result of beta-receptor subsensitivity. Oral and inhaled corticosteroids have been used for the treatment of acute asthma and COPD in the elderly patient. Long-term treatment with oral corticosteroids can result in serious systemic adverse effects such as suppressed adrenal function, bone loss, skin thinning and cataract formation. In contrast to beta(2)-agonists, oral corticosteroids can upregulate beta(2)-adrenoceptors and thereby potentiate the systemic sequelae of beta(2)-agonists. Hence, oral corticosteroids should be administered with caution for as short a duration as possible. Inhaled corticosteroids appear to be relatively well tolerated when administered at doses below approximately 1000 microg. However, larger doses of inhaled corticosteroids may affect hypothalamic-pituitary-adrenal function and bone turnover. In the case of inhaled corticosteroids, spacer devices, often used in older patients who cannot operate metered dose inhalers, can potentiate the systemic sequelae of both corticosteroids and beta(2)-agonists. The use of theophyllines in the treatment of COPD or chronic asthma is controversial. Theophyllines have a wide adverse effect profile and are prone to drug-drug interactions. The adverse effects may be mild or life threatening and include nausea and vomiting or sinus and supraventricular tachycardias. Therefore, theophyllines should be prescribed with extreme caution to elderly patients with asthma or COPD. In contrast, inhaled anticholinergic drugs such as ipratropium bromide and oxitropium bromide are generally safe in elderly patients and have useful bronchodilator function. Commonly reported adverse effects are an unpleasant taste and dryness of the mouth. When used as first-line therapy, anticholinergic drugs may optimise the bronchodilator effects of low-dose inhaled beta(2)-agonists in patients with chronic airflow obstruction, and hence obviate the need for higher doses.

Clinical pharmacokinetics of inhaled budesonide

The corticosteroid budesonide is a 1:1 racemic mixture of 2 epimers, (22R)- and (22S)-, and is available in 3 different inhaled formulations for the management of asthma: a pressurised metered dose inhaler (pMDI), a dry powder inhaler (DPI) and a solution for nebulised therapy. Inhaled corticosteroids such as budesonide reach the systemic circulation either by direct absorption through the lungs (a route that is much more important than previously recognised) or via gastrointestinal absorption of drug that is inadvertently swallowed. Although the pharmacokinetics of budesonide have been extensively investigated following oral and intravenous administration, relatively few studies have defined the systemic disposition of budesonide after inhalation. Drug deposition in the lungs depends on the inhaler device: 15% of the metered dose of budesonide reached the lung with a pMDI compared with 32% with a breath-actuated DPI. In patients with asthma (n = 38) receiving different doses of budesonide by DPI (Turbuhaler), the pharmacokinetic parameters peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) were dose-dependent after both single dose and repeat dose (3 weeks) administration: time to Cmax (tmax) was short (0.28 to 0.40 hours) and the elimination half-life approximately 3 hours. Both AUC and Cmax were linearly related to budesonide dose. In a small group of healthy male volunteers (n = 9), the pharmacokinetics of budesonide 1,600 microg twice daily via pMDI were assessed on the fifth day of administration. Mean model-independent parameters for (22R)-budesonide were as follows: Cmax 1.8 microg/L, tmax 0.46 hours, elimination half-life 2.3 hours and oral clearance 163 L/h, and there were no enantiomer-specific differences in drug disposition. Budesonide undergoes fatty acid conjugation within the lung, but very limited pharmacokinetic data are available to define the pulmonary absorption characteristics. There is evidence from a population analysis that the pulmonary absorption of budesonide is prolonged and shows wide interindividual variation. Further pharmacokinetic studies are required to define the time-course of budesonide absorption through the lung in specific patient groups, and to investigate the effect of new inhaler devices (especially chlorofluorocarbon-free pMDIs) on the pharmacokinetic profile and systemic drug exposure.

Deposition and pharmacokinetics of flunisolide delivered from pressurized inhalers containing non-CFC and CFC propellants

Our objective was to assess the deposition and pharmacokinetics of a novel formulation of flunisolide (Aerobid, Forest Laboratories) in hydrofluoroalkane (HFA) 134a delivered by pressurized metered dose inhaler (pMDI). The design was a two-way crossover investigation in 12 healthy male subjects comparing HFA-134a flunisolide by pMDI versus pMDI plus 50 mL spacer device. Four of these subjects also took part in a two-way crossover investigation comparing chlorofluorocarbon (CFC) flunisolide pMDI versus pMDI plus Aerochamber holding chamber. The imaging technique of gamma scintigraphy was used to quantify total and regional lung deposition of flunisolide. Plasma levels of flunisolide and its major metabolite (6beta-OH flunisolide) were also determined. The spacer and Aerochamber reduced oropharyngeal deposition dramatically for both the HFA and CFC products (mean 59.8 to 14.9% (p < 0.01) of ex-valve (metered) dose for HFA product; 66.3 to 12.3% (p < 0.01) of ex-valve dose for CFC product) owing to deposition of part of the dose on the walls of the add-on devices themselves. Lung deposition averaged 22.6 and 40.4% (p < 0.01) of the ex-valve dose for the HFA formulation used with pMDI alone and with pMDI plus spacer. Mean lung deposition of the CFC formulation delivered via the Aerochamber (mean 23.4%) was higher than that for the CFC pMDI alone (mean 17.0%), but this difference was not statistically significant. Lung deposition expressed as percentage ex-device (delivered) dose averaged 68.3% for HFA pMDI plus spacer and 19.7% for CFC pMDI. Plasma levels of flunisolide were higher for the pMDI plus spacer than for pMDI alone, reflecting higher lung deposition via the spacer, but plasma levels of the 6beta-OH flunisolide metabolite were higher for the pMDI alone as a consequence of higher oropharyngeal deposition. When delivered via the spacer, pulmonary targeting of the flunisolide HFA formulation was improved compared with the CFC formulation, which should benefit patients by providing satisfactory asthma therapy from a much-reduced delivered dose of flunisolide.

Flunisolide HFA vs flunisolide CFC: pharmacokinetic comparison in healthy volunteers

Two preparations of flunisolide, an inhaled corticosteroid, were compared in a parallel, multiple-dose study of 31 healthy volunteers. The new flunisolide preparation substitutes hydrofluoroalkane (HFA) for chlorofluorocarbon (CFC) as a propellant and incorporates a spacer into its pressurized metered-dose inhaler (pMDI). In this study, subjects were randomly assigned to receive flunisolide CFC 1000 microg bid; flunisolide HFA 170 microg bid; or flunisolide HFA 340 microg bid. Dosing was continued for 13.5 days. Plasma samples were analyzed after the first dose on day 1 and again after 13.5 days of treatment. No significant differences in day 1 dose-adjusted peak plasma concentrations (C(max)) were observed. Dose proportionality in C(max) and area under the concentration--time curves (AUC) was observed for the flunisolide HFA 170 and 340 microg bid groups on days 1 and 14. Day 1 mean dose-adjusted AUC was significantly greater in the flunisolide CFC 1000 microg bid group than in either flunisolide HFA group, indicating greater systemic availability of flunisolide CFC. Oral clearance and volume of distribution were significantly higher for flunisolide CFC than for flunisolide HFA. This may be due to greater oropharyngeal deposition by the flunisolide CFC formulation. Another indicator of greater flunisolide CFC oropharyngeal deposition was observed in C(max) and AUC(0--tlast) values for 6beta-OH flunisolide, the first-pass metabolite of flunisolide. The values of these pharmacokinetic parameters were significantly higher in the flunisolide CFC group than in the 340 microg bid flunisolide HFA group on days 1 and 14. However, this was not the case for cortisol values where flunisolide HFA accounted for less oropharyngeal deposition and more targeted delivery without adverse events. The study demonstrated that flunisolide HFA administered through a pMDI with built-in spacer was safe and well tolerated in healthy volunteers.

Patient self-management of acute asthma: adherence to national guidelines a decade later

BACKGROUND AND OBJECTIVES

Children in the emergency department (ED) with acute asthma were enrolled to assess the impact of asthma on their activities of daily living and evaluate their access to care and preventive strategies, determine the proportion who adhered to the National Heart, Lung, and Blood Institute (NHLBI) guidelines for proper steps to take at home during an acute asthma exacerbation, and compare adherence rates for those with persistent and mild intermittent asthma.

DESIGN AND METHODS

Children 2 to 18 years old who presented to the Children's Hospital of Philadelphia's ED with acute asthma exacerbations were enrolled prospectively. Parents and patients completed the 108-item Asthma Exacerbation Response Questionnaire with a focus on determining the home management steps they took both at the onset of the asthma exacerbation and just before coming to the ED.

RESULTS

Among the 433 children studied, 76% had at least 1 doctor visit, 75% had at least 1 ED visit, and 43% had at least 1 hospitalization for asthma in the preceding 12 months. Overall, 64% had persistent asthma by NHLBI criteria, yet just 4% were cared for by an allergist or pulmonologist, 38% took daily anti-inflammatory therapy, and 18% received a daily inhaled corticosteroid. Also, 48% did not use a holding chamber with their metered-dose inhalers, and 66% did not use their peak flow meters. Regarding exacerbation response, 71% did not have a written action plan, and 89% did not maintain a symptom diary. Both at the onset of wheezing and just before coming to the ED, administration of a beta2-agonist was the only step that the majority of children performed. One-third or fewer followed the other steps recommended by the NHLBI, including using a peak flow meter, beginning oral corticosteroids, calling or going to see the doctor, or going to the ED. Children with persistent asthma were not more adherent to the guidelines than those with mild intermittent disease.

CONCLUSIONS

Asthma has a significant adverse effect on the lives of these children. The NHLBI guidelines, first published a decade ago, were designed to reduce asthma's increasing morbidity and mortality, but this study uncovered a high rate of nonadherence with many aspects of the guidelines, including preventive strategies and home management of an exacerbation.

Assessment of the systemic effects of budesonide inhaled from Easyhaler and from Turbuhaler in healthy male volunteers

The main objective of this study was to show dose-dependent equivalence in the systemic activity of budesonide 800 microg day(-1) and 1600 microg day(-1) delivered from either Easyhaler or Turbuhaler in healthy male subjects. This single-centre study was carried out according to a randomized, double-blind, double-dummy, five-way crossover design over a 9-week period. All subjects received 1 week of treatment with the following, in randomized order, with a washout week between each treatment: budesonide Easyhaler 800 microg day(-1) plus placebo Turbuhaler; budesonide Easyhaler 1600 microg day(-1) plus placebo Turbuhaler; placebo Easyhaler plus Pulmicort Turbuhaler 800 microg day(-1); placebo Easyhaler plus Pulmicort Turbuhaler 1600 microg day(-1); placebo Easyhaler plus placebo Turbuhaler. The final inhalation of study drug was performed at the study centre, where blood and urine samples were collected. Fifteen subjects were recruited and all completed the study. Mean serum cortisol AUC0-20 values (the primary outcome variable) were comparable for each device at the two dose levels, and met the defined criteria for equivalence (90% CI 0.8-1.25 for between-treatment difference). Budesonide 800 microg day(-1) caused minimal suppression of serum cortisol AUC0-20 values, Budesonide 1600 microg day(-1) statistically significantly suppressed serum cortisol AUC0-20 values compared with placebo. Mean morning serum cortisol values were within the reference range in al treatment groups. At a budesonide dose of 800 microg day(-1) mean urine cortisol/creatinine ratio was statistically significantly higher with Easyhaler than with Turbuhaler, but there was no significant difference between the devices at the 1600 microg day(-1) dose. Serum budesonide concentrations were equivalent for each device at both dose levels. Adverse drug reactions were infrequent and mild in nature and there were no clinically significant changes in laboratory safety variables. In conclusion, in healthy male volunteers, budesonide 800 microg day(-1) and 1600 microg day inhaled from Easyhaler had comparable systemic effects to the same doses inhaled via Turbuhaler.

Does the mode of inhalation affect the bronchodilator response in patients with severe COPD?

Spacing devices improve lung deposition of aerosols from metered dose inhalers (MDI) but it is sometimes difficult for dyspnoeic patients to perform maximal breaths with breath-holds needed to inhale the aerosols from them. Our aim was to determine whether the response to bronchodilators (BD) depended on the method of inhalation. We studied 20 patients with moderately severe chronic obstructive pulmonary disease (COPD) with a mean age of 68 years and a mean of forced expiratory volume in 1 sec (FEV1) of 41% predicted. In a randomized, cross-over fashion they inhaled terbutaline 1.5 mg (six puffs) followed by ipratropium 120 microg (six puffs) via MDI and nebuhaler with either two inspirations to total lung capacity and a 10-sec breath-hold per puff or with six tidal breaths per puff. Before and after BDs we measured FEV1, forced vital capacity (FVC), airways resistance using interrupter method (Rint) and 6-min walking distance (6MWD). Subsequently, we re-tested nine of these patients with the two methods of inhalation, before and after conventional doses (terbutaline 500 microg+ipratropium 40 microg), then after terbutaline 1 mg and ipratropium 80 microg and finally after nebulized terbutaline 5 mg and ipratropium 500 microg to sec whether there was a dose-dependent difference in effect between the two methods. Spirometry, slow vital capacity (SVC). inspiratory capacity and shuttle walking tests were monitored. In the original 20 patients there were highly significant improvements in all parameters after inhalers, with no significant difference between methods of inhalation. Median improvements after BDs were: FEV1 0.221 and 0.191, FVC 0.501 and 0.381 and 6MWD 40 m and 44 m, for maximal breaths and tidal breathing, respectively. For nine patients, tidal and maximal breaths produced similar effects on lung function and exercise tolerance at both doses of BDs. Nebulized BDs only improved shuttle distances slightly when compared with either method of inhalation from MDI and spacer but had no additional effect on lung function. In conclusion, in patients with moderately severe COPD, BDs given by metered dose inhaler via nebuhaler have similar effects whether given by six easy tidal breaths or the more difficult two maximal breaths with breath-hold. This holds true at small or larger doses of BD. Either method of inhaling six puffs of the BDs can be used as an effective alternative to nebulized aerosol.

Inhaled corticosteroids as first-line therapy for asthma. Why they work--and what the guidelines and evidence suggest

Despite a plethora of clinical guidelines and evidence outlining the efficacy of inhaled corticosteroids, these medications continue to be underused in the treatment of asthma. This article reviews the justification for prescribing inhaled steroids as first-line therapy, discusses indications for their use, and compares potencies of the various products now available. In addition, the authors address the adverse effects commonly associated with these agents and provide evidence supporting early intervention with inhaled steroids in the treatment of persistent asthma.

Inhaled corticosteroids reduce growth. Or do they?

The class label warning in the United States for inhaled corticosteroids (ICS's) states that these drugs may reduce growth velocity in children. In this paper, the evidence for this warning is reviewed from a clinical point of view. Children with asthma tend to grow slower than their healthy peers during the prepubertal years because they go into puberty at a later age. However, asthmatic children do achieve a (near) normal adult height. In randomized controlled clinical trials, the use of inhaled beclomethasone, budesonide and fluticasone is associated with a reduced growth during the first months of therapy, in the order of magnitude of approximately 0.5-1.5 cm x yr(-1). It is, however, unlikely that such an effect continues or persists because accumulating evidence shows that asthmatic children, even when they have been treated with ICS for years, attain normal adult height. Individual rare cases have been reported, however, where ICS use was associated with clinically relevant growth suppression. Inhaled corticosteroids are the most effective therapy available for maintenance treatment of childhood asthma. Fear of reduced growth velocity is based on exceptional cases and not on group data. It should, therefore, not be a reason to withhold or withdraw such highly effective treatment in children with asthma.

Late onset asthma: epidemiology, diagnosis and treatment

Asthma is common among older persons, affecting approximately 4 to 8% of those above the age of 65 years. Despite its prevalence, late onset asthma may be misdiagnosed and inadequately treated, with important negative consequences for the patient's health. The histopathology of late onset disease appears to be similar to that of asthma in general, with persistent airway inflammation a characteristic feature. It is less clear, however, that allergic exposure and sensitisation play the same role in the development of disease in adults as they do in children. Atopy is less common among those with late onset asthma, and the prevalence of elevated immunoglobulin E levels is lower among those aged over 55 years of age than younger patients. Occupational asthma is an aetiological consideration unique to adult onset disease, with important implications for treatment. The differential diagnosis for cough, wheeze, and dyspnoea in the elderly is broad, and includes chronic obstructive bronchitis, bronchiectasis, congestive heart failure, lung cancer with endobronchial lesion and vocal cord dysfunction. Keys to accurate diagnosis include a good history and physical examination, the demonstration of reversible airways obstruction on pulmonary function tests and a favorable response to treatment. Inhaled corticosteroid therapy is recommended for patients with persistent disease, and careful instruction in the use of metered-dose inhalers is particularly important for the elderly.

Can lung deposition data act as a surrogate for the clinical response to inhaled asthma drugs?

Studies involving the direct measurement of clinical response to inhaled asthma drugs, especially inhaled corticosteroids, may be very difficult to conduct. However, the deposition of drug in the lungs may be considered as a measure of local bioavailability, and may be quantified by radionuclide imaging techniques, or for some drugs by pharmacokinetic methods. This paper reviews evidence for considering lung deposition data as a surrogate for the clinical response to inhaled asthma drugs, based mainly upon a series of case histories. The appropriate use of lung deposition data in regulatory packages, especially to document the equivalence or comparability of two products, offers the possibility of significant time saving in the drug development process, and hence a faster drug development programme for inhaled asthma products.

Inhibitory activity of fenoterol on Dermatophagoides-, Parietaria-, tetanus-toxoid-, and Candida albicans-stimulated blood mononuclear cells: differences in beta2-adrenoreceptor stimulation but not in cell apoptosis

beta2-adrenoreceptor agonists have the ability to downregulate in vitro the proliferative response of peripheral blood mononuclear cells (BMCs). This activity could be related to a variety of beta2-adrenoreceptor-mediated functions, including induction of cell apoptosis in activated T-cells. To test this hypothesis, BMCs from atopic subjects, sensitized to house dust mites (Dermatophagoides [Der p]) and/or to Parietaria were incubated with fenoterol (10(-8)-10(-5) M) in the presence of (a) purified allergen extracts (Der p [5 microg/mL] or Parietaria [5 microg/mL]) or (b) antigens (tetanus toxoid [1 microg/mL] or Candida albicans [5 x 10(5) bodies/mL]). The BMC proliferation was assessed by [3H] thymidine incorporation and cell apoptosis was assessed by evaluating DNA fragmentation by a fluorescence technique, using propidium iodide. In cultures stimulated with Der p or with Parietaria, fenoterol induced a dose-dependent inhibition of BMC proliferation, significant also at the lowest concentration tested (10(-8) M) (p < 0.05, each comparison). In contrast, the inhibitory activity of the drug on tetanus-toxoid-stimulated BMCs was significant only at the highest dose tested (10(-5)M) (p < 0.05), whereas no effect was seen when BMCs were stimulated with C. albicans extract (p > 0.05). The different inhibitory efficacy of fenoterol appeared to be related to the degree of activation of beta2-adrenoreceptors on the different BMC populations that responded to the different stimuli. Indeed, in the presence of fenoterol (10(-6) and 10(-5)M), a significant increase in cyclic adenosine monophosphate (cAMP) levels was seen in Der p- or Parietaria-stimulated cells (p < 0.05; each comparison), but not in cell cultures stimulated with tetanus toxoid or with C. albicans extracts (p > 0.05; each comparison). Finally, the percentage of cells with fragmented DNA was lower in cultures stimulated with Der p or Parietaria than in those stimulated with tetanus toxoid or C. albicans, and the presence of fenoterol did not modify cell apoptosis (p > 0.05; each comparison). Thus, the different inhibitory activity of fenoterol on BMCs activated by allergens (Der p or Parietaria) or by antigens (tetanus toxoid or C. albicans) seems to be related to differences in beta2-adrenoreceptor expression and/or function in the different antigen-specific T-cell subsets, but it is not influenced by changes in cell apoptosis.

Inhaled corticosteroids for asthma therapy: patient compliance, devices, and inhalation technique

BACKGROUND

Patient compliance, inhalation devices, and inhalation techniques influence the effectiveness of inhaled medications.

METHODS

This article presents the results of a systematic literature review of studies measuring compliance with inhaled corticosteroids, measuring inhalation technique with different inhalation devices, and estimating the proportion of inhaled drug that is deposited in the lung.

RESULTS

Overall, patients took the recommended doses of inhaled medication on 20 to 73% of days. Frequency of efficient inhalation technique ranged from 46 to 59% of patients. Education programs have been shown to improve compliance and inhalation techniques. The lung deposition achieved with different inhalers depends on particle size as well as inhaler technique.

CONCLUSION

This review demonstrates that multiple factors may come between a prescription of an inhaled corticosteroid and the arrival of that medicine at its target organ, the lung.

Aerosol therapy for asthma

Inhaled drugs play an important role in asthma management. The correct use of an appropriate delivery device is necessary to achieve the desired therapeutic effects of the drug. Currently, chlorofluorocarbon-propelled metered-dose inhalers, with or without spacers, are the most popular aerosol delivery devices. With the planned phase out of the chlorofluorocarbon metered-dose inhalers, the use of other delivery devices is being emphasized. To achieve optimal therapeutic effects, the drug and the delivery device should be considered a "couple". Aerosol delivery devices should provide an adequate "drug dose to the lung", be cost effective, simple to operate, minimize oropharyngeal deposition and systemic side effects, and match the patient's requirements. A new generation of aerosol delivery devices, incorporating the latest advances in aerosol technology, is likely to fulfill many of the goals mentioned above.

Canadian Asthma Consensus Report, 1999. Canadian Asthma Consensus Group

OBJECTIVES

To provide physicians with current guidelines for the diagnosis and optimal management of asthma in children and adults, including pregnant women and the elderly, in office, emergency department, hospital and clinic settings.

OPTIONS

The consensus group considered the roles of education, avoidance of provocative environmental and other factors, diverse pharmacotherapies, delivery devices and emergency and in-hospital management of asthma.

OUTCOMES

Provision of the best control of asthma by confirmation of the diagnosis using objective measures, rapid achievement and maintenance of control and regular follow-up.

EVIDENCE

The key diagnostic and therapeutic recommendations are based on the 1995 Canadian guidelines and a critical review of the literature by small groups before a full meeting of the consensus group. Recommendations are graded according to 5 levels of evidence. Differences of opinion were resolved by consensus following discussion.

VALUES

Respirologists, immunoallergists, pediatricians and emergency and family physicians gave prime consideration to the achievement and maintenance of optimal control of asthma through avoidance of environmental inciters, education of patients and the lowest effective regime of pharmacotherapy to reduce morbidity and mortality.

BENEFITS, HARMS AND COSTS

Adherence to the guidelines should be accompanied by significant reduction in patients' symptoms, reduced morbidity and mortality, fewer emergency and hospital admissions, fewer adverse side-effects from medications, better quality of life for patients and reduced costs.

RECOMMENDATIONS

Recommendations are included in each section of the report. In summary, after a diagnosis of asthma is made based on clinical evaluation, including demonstration of variable airflow obstruction, and contributing factors are identified, a treatment plan is established to obtain and maintain optimal asthma control. The main components of treatment are patient education, environmental control, pharmacotherapy tailored to the individual and regular follow-up.

VALIDATION

The recommendations were distributed to the members of the Canadian Thoracic Society Asthma and Standards Committees, as well as members of the board of the Canadian Thoracic Society. In addition, collaborating groups representing the Canadian Association of Emergency Physicians, the Canadian College of Family Physicians, the Canadian Paediatric Society and the Canadian Society of Allergy and Immunology were asked to validate the recommendations. The recommendations were discussed at regional meetings throughout Canada. They were also compared with the recommendations of other similar groups in other countries. DISSEMINATION AND IMPLEMENTATION: An implementation committee has established a strategy for disseminating these guidelines to physicians, other health professionals and patients and for developing tools and means that will help integrate the recommendations into current asthma care. The plan is outlined in this report.

Evaluation of the effect of a large volume spacer on the systemic bioactivity of fluticasone propionate metered-dose inhaler

BACKGROUND

Inhaled corticosteroids such as fluticasone propionate (FP) have dose-related systemic effects, including adrenal suppression. We have therefore investigated the effect of adding a large volume spacer on the systemic bioactivity of FP given via a pressurized metered-dose inhaler (pMDI).

METHODS

Fourteen healthy volunteers (mean age, 29.9 years old) were studied using an open, randomized, placebo-controlled, three-way crossover design. Single doses of the following were given at 5:00 PM in a randomized sequence: (1) eight puffs of FP by pMDI, 1.76 mg (250 microg ex-valve, 220 microg ex-actuator); (2) eight puffs of FP by pMDI, 250 microg, with 750-mL spacer (Volumatic; Allen & Hanburys; Uxbridge, UK); and (3) eight puffs of placebo by pMDI. Measurements were made after each dose, including overnight and early morning urinary cortisol/creatinine ratios and 8:00 AM serum cortisol.

RESULTS

Significant (p < 0.05) suppression of all three end points occurred with each active treatment compared to treatment with placebo. Furthermore, significant (p < 0.05) additional suppression occurred when comparing FP by pMDI alone to FP by pMDI with spacer. Geometric mean fold differences (95% confidence interval for fold difference) between FP by pMDI alone and FP by pMDI with spacer were 1.94-fold (1.00-3.78) for overnight urinary cortisol/creatinine ratio and 1.98-fold (1.26-3.10) for 8:00 AM serum cortisol. This was mirrored by a twofold rise in the number of values for uncorrected overnight urinary cortisol < 10 nmol/10 h: placebo treatment (none of 14 subjects); FP by pMDI (6 of 14 subjects; 43%); and FP by pMDI with spacer (12 of 14 subjects; 86%).

CONCLUSIONS

The use of a large volume spacer with FP by pMDI results in a twofold increase in the systemic bioavailability as assessed by sensitive measures of adrenal suppression. This, in turn, reflects a twofold improvement in respirable dose delivery with the spacer device.

Comparison of albuterol delivered by a metered dose inhaler with spacer versus a nebulizer in children with mild acute asthma

OBJECTIVE

In children with mild acute asthma, to compare treatment with a single dose of albuterol delivered by a metered dose inhaler (MDI) with a spacer in either a weight-adjusted high dose or a standard low-dose regimen with delivery by a nebulizer.

STUDY DESIGN

In this randomized double-blind trial set in an emergency department, 90 children between 5 and 17 years of age with a baseline forced expiratory volume in 1 second (FEV1 ) between 50% and 79% of predicted value were treated with a single dose of albuterol, either 6 to 10 puffs (n = 30) or 2 puffs (n = 30) with an MDI with spacer or 0.15 mg/kg with a nebulizer (n = 30).

RESULTS

No significant differences were seen between treatment groups in the degree of improvement in percent predicted FEV1 (P =.12), clinical score, respiratory rate, or O2 saturation. However, the nebulizer group had a significantly greater change in heart rate (P =.0001). Our study had 93% power to detect a mean difference in percent predicted FEV1 of 8 between the treatment groups.

CONCLUSION

In children with mild acute asthma, treatment with 2 puffs of albuterol by an MDI with spacer is just as clinically beneficial as treatment with higher doses delivered by an MDI or by a nebulizer.

Estimation of pulmonary deposition of aerosol using gamma scintigraphy

Following delivery of technetium 99m-labeled aerosols through a ventilator circuit, the amount of radioactivity in the lungs of 58 ventilated rabbits was estimated first by gamma scintigraphy via gamma camera and later by direct counting of the excised lungs (n = 116 specimens) with a gamma counter. The in situ radioactivity measured via scintigraphy was closely correlated with the gamma counter ex vivo tissue counts of the radioactivity (R2 = 0.997, P < 0.001). Overall, gamma scintigraphy gave slightly lower values of activity than the tissue counts from the gamma counter, but the limits of agreement between the two measurements were narrow enough for us to consider that the tissue and scintigraphy methods were in agreement. We conclude that gamma scintigraphy provides a convenient and noninvasive means for the accurate estimation of aerosol deposition in the lungs of small animals and possibly in small infants.

beta 2-agonist-induced inhibition of neutrophil chemotaxis is not associated with modification of LFA-1 and Mac-1 expression or with impairment of polymorphonuclear leukocyte antibacterial activity

Patients with chronic obstructive lung disorders often show increased susceptibility to airway infections. As beta 2-adrenoceptor agonists, in addition to reversing the contractile response of bronchial smooth muscles, may inhibit a variety of inflammatory and immuno-effector cell functions, it is possible that these drugs interfere with host defence mechanisms. The present study was designed to test in vitro whether fenoterol, a short-acting beta 2-adrenoceptor agonist, could modify human blood neutrophil recruitment and antimicrobial activity. Pre-exposure to fenoterol significantly reduced neutrophil migration towards the complement component C5a, at concentrations ranging from 10(-7) M to 10(-5) M, or towards lipopolysaccharide, at a concentration of 10(-5) M (P < 0.05, each comparison). In contrast, the drug (10(-8)-10(-5) M) did not significantly modify the increased expression of lymphocyte function-associated antigen (LFA-1, i.e. CD11a/CD18) the macrophage antigen-1 (Mac-1, i.e. CD11b/CD18) induced by N-formylmethionylleucylphenylalanine (fMLP) (P > 0.05, each comparison). Finally, incubation of neutrophils with fenoterol (10(-8)-10(-5) M) did not significantly influence phagocytosis or intracellular killing of bacteria (Staphylococcus aureus) or H2O2 release induced by tetradecanoyl-phorbol-acetate (P > 0.1 for each comparison). These results suggest that short-acting beta 2-adrenoceptor agonists, such as fenoterol, are able partially to reduce neutrophil recruitment in the airways without interfering with the processes involved in phagocytic activity against bacteria.

Imaging techniques for assessing drug delivery in man

In vivo imaging technologies have a vital role to play in the pharmaceutical development process. Gamma scintigraphy, comprising two-dimensional 'planar' imaging, is used widely to visualize and to quantify drug delivery, particularly by the oral and pulmonary routes. However, three-dimensional imaging modalities - single photon emission computed tomography (SPECT), positron emission tomography (PET) and magnetic resonance imaging (MRI) - may also have applications within this area. Single photon emission computed tomography and PET offer potential advantages over gamma scintigraphy in the assessment of regional lung deposition from aerosol inhalers, but these advantages are greatly outweighed by the practical problems associated with conducting SPECT and PET studies. It is concluded that, for the foreseeable future, gamma scintigraphy is the imaging modality of choice in assessing the delivery of new oral and pulmonary drug products.

The effect of breathing frequency on deposition of drug aerosol using an inhalation-synchronized dosimeter in healthy adults

The deposition of inhaled drug aerosol between the tongue, the upper and lower respiratory tract, the lungs and the gastrointestinal tract (GI tract) in 11 healthy adults was studied by using a nebulizer with an inhalation-synchronized dosimeter. The effect of breathing frequency on deposition was studied using radioaerosol (mixture of salbutamol and technetium bound to diethylenetriamine pentacetate, [99mTc]DTPA) and a gamma-camera. In healthy subjects who were breathing at their own frequency (16 +/- 5 breaths min-1, mean +/- SD), the proportion of inhaled aerosol deposited in the lungs was 48 +/- 14 (mean percentage +/- SD). The proportion deposited in the upper airway tract and the GI tract was 19 +/- 13 and 25 +/- 9 respectively, and the remainder was deposited on the tongue (6 +/- 4) and in the lower airway tract (3 +/- 2). Guided, slower breathing frequency (11 +/- 5 breaths min-1) changed the deposition remarkably. The proportion of the pulmonary deposition of the inhaled dose increased significantly (P < 0.004) to 60 +/- 17, and the proportion of the upper airway tract deposition decreased significantly (P < 0.005) by half of the initial deposition. We conclude that a slow controlled breathing frequency is an important factor if we want to increase the drug deposition in the lungs. It is also essential in decreasing the variation in the deposition of the lungs.

Reservoir design and dose availability with long-term metered dose inhaler corticosteroid use

The effect of reservoir design and long-term use with inhaled metered dose inhaler (MDI) corticosteroids on aerosol dose availability was examined. Beclomethasone dipropionate (Vanceril) was delivered by MDI with three brands of available reservoir devices: the AeroChamber, the OptiHaler, and the Aerosol Cloud Enhancer (ACE). An in vitro lung model simulated inspiration. Long-term use was simulated by exhausting five MDI canisters of beclomethasone through each sample of reservoir tested. Each canister exhausted through a reservoir represented approximately 1 month of use with one drug. Total inhaled dose was collected at the reservoir mouthpiece and measured using a spectrophotometric assay. Dose delivery was measured before simulated use and after each MDI canister was exhausted through the reservoir. Three samples of each brand were tested with cleaning and three samples were tested without cleaning. With cleaning, the AeroChamber, OptiHaler, and ACE delivered significantly different average doses of 16.6, 10.3, and 8.7 micrograms per MDI actuation, respectively, (P = 0.0017) over time of use. Changes in dose delivery over time of use were not significant (P = 0.2011). Without cleaning, the same three brands averaged 21.1, 9.7, and 7.8 micrograms per MDI actuation, respectively, (P = 0.0019), and changes in dose delivery over time were not significant (P = 0.3265). Reservoir design can affect the delivery of an inhaled corticosteroid, although the delivery over 4 to 5 months remained stable.

Salbutamol treatment of acute severe asthma in the ED: MDI versus hand-held nebulizer

The objectives of this study were to compare the efficacy of salbutamol delivered by either metered-dose inhaler plus spacer (MDI-spacer) or by wet nebulization (NEB), and to determine the relationships between physiologic responses and plasma salbutamol concentrations. Asthmatic patients presenting to the emergency department (ED) with acute severe asthma (forced expiratory volume in the first second [FEV1] less than 50% of predicted) were enrolled in a randomized, double-blind, parallel-group study. The MDI-spacer group received salbutamol, delivered via MDI into a spacer device, in four puffs actuated in rapid succession at 10-minute intervals (2.4 mg/h). The NEB group was treated with nebulized salbutamol, 1.5 mg, via nebulizer at 15-minute intervals (6 mg/h). Doses were calculated on the basis of the percentage of total dose that reaches the lower airway with both methods. The protocol involved 3 hours of this treatment. Mean peak expiratory flow rate (PEFR) and FEV1 improved significantly over baseline values for both groups (P=.01). However, there were no significant differences between both groups for PEFR and FEV1 at any point studied. The examination of the relationships between cumulative dose of salbutamol and change in FEV1 showed a significant linear relationship (P=.01) for both methods (MDI r=.97; NEB r=.97). The regression equations showed that for every 1 mg of salbutamol by MDI-spacer, 2.5 mg are needed from nebulization to have equal therapeutic response. At the end of treatment, the salbutamol plasma levels were 10.1+/-1.6 ng/ml for the MDI-spacer group and 14.4+/-2.3 ng/ml for the NEB group (P=.0003). Both groups showed a nonsignificant heart rate decrease. A significant group-by-time interaction means that differences between groups increased with time (P=.04). Additionally, the NEB group presented a higher incidence of tremor (P=.03) and anxiety (P=.04), reflecting larger systemic absorption of salbutamol. These data indicate that when doses used are calculated on the basis of the percentage of total drug that reaches the lower airway, there was equivalent bronchodilatation after salbutamol administered by either MDI-spacer or nebulization in patients with acute severe asthma. However, nebulizer therapy produced greater side effects related to the increase in salbutamol absorption and higher plasma level.

Early lung absorption profile of non-CFC salbutamol via small and large volume plastic spacer devices

AIMS

To evaluate the lung dose of a non-CFC salbutamol metered dose inhaler (MDI) formulation via three commonly used plastic spacer devices, of both large and small volume, compared with the MDI used on its own.

METHODS

Ten healthy volunteers were studied in a randomized single (investigator) blind crossover design. Single 1200 microg nominal doses of salbutamol from a non-CFC MDI (Airomir), as 12 sequential 100 microg puffs over 6 min, were delivered from the MDI alone and via two large volume spacer devices (Nebuhaler, Volumatic), and a small volume spacer (Aerochamber). All spacers were prewashed prior to each study day and mouth rinsing was performed after each drug sequence. Plasma salbutamol was measured at 5, 10, 15 and 20 min, with calculation of maximum (Cmax) and average (Cav) concentrations. This lung dose was assessed using the early lung absorption profile of salbutamol in the first 20 min after inhalation.

RESULTS

Both of the large volume spacers, the Nebuhaler and the Volumatic, delivered significantly more salbutamol than the MDI alone. For Cav this amounted to a 2.07-fold difference (95% CI 1.48-2.90) between Nebuhaler vs MDI, and a 1.49-fold difference (95%CI 1.19-1.87) between Volumatic vs MDI. The Nebuhaler also produced greater deposition than either the Volumatic or the Aerochamber spacers; Nebuhaler vs Volumatic: 1.39-fold difference (95% CI 1.09-1.76), Nebuhaler vs Aerochamber: 1.63-fold difference (95% CI 1.20-2.21). There were no significant differences between the Aerochamber and the MDI alone.

CONCLUSIONS

Using the early lung absorption profile, for administration of the same nominal dose, both of the large volume spacers (Nebuhaler and Volumatic) but not the small volume spacer (Aerochamber) delivered significantly more salbutamol than the MDI alone. The Nebuhaler also produced greater delivery than either the Volumatic or the Aerochamber spacer devices. Our results show that whilst lung delivery of non-CFC salbutamol MDI is improved by the use of a plastic spacer, there may be appreciable differences in performance, particularly between large and small volume devices.

Metered-dose inhaler to deliver methacholine in bronchial provocation testing: a pilot study

BACKGROUND

Nonspecific bronchial provocation tests may be simplified by the use of hand-held devices to deliver methacholine.

OBJECTIVE

To study the feasibility of using a metered-dose inhaler (MDI) to administer methacholine in bronchial provocation tests, and the ability of such a device to diagnose bronchial hyperresponsiveness (BHR) accurately.

METHODS

In an open randomized crossover pilot study, we compared the provocative dose that induces a 20% fall in FEV1 (PD20 FEV1) obtained with the methacholine MDI with that obtained using a conventional nebulizer in 20 hyperresponsive and 20 nonhyperresponsive subjects. The MDI delivers 400 doses of 100 microg of methacholine, and was used via a spacer. Bronchial hyperresponsiveness (BHR) was defined as a PD20 FEV1 <2,000 microg with the conventional test using the nebulizer. The tests were performed in each subject in a randomized order, 1 to 7 days apart.

RESULTS

Of the subjects who had a nebulizer PD20 FEV1 <2,000 microg, all but one had an MDI PD20 FEV1 <800 microg. When 800 microg was taken as the threshold for the diagnosis of BHR with the MDI test, the accuracy of this test to diagnose BHR was 97.5%, and the two tests were highly concordant for the diagnosis of BHR (Pearson chi2, 36.19; p<0.0001).

CONCLUSION

A hand-held device may be suitable for delivery of methacholine during bronchial provocation tests, if these results are confirmed in large samples.

Lung deposition of fenoterol and flunisolide delivered using a novel device for inhaled medicines: comparison of RESPIMAT with conventional metered-dose inhalers with and without spacer devices

STUDY OBJECTIVES

To compare lung deposition of fenoterol or flunisolide administered from a novel, multidose inhalation device delivering liquid droplets (RESPIMAT; Boehringer Ingelheim Ltd; Bracknell, UK) or from conventional metered-dose inhalers (MDIs) with and without spacers.

DESIGN

Two randomized, three-way crossover studies.

SETTING

Clinical research laboratory.

PARTICIPANTS

Healthy, nonsmoking volunteers.

INTERVENTIONS

In one study, radiolabeled aerosols of fenoterol from the RESPIMAT device and from a conventional MDI with or without an Aerochamber spacer (Trudell Medical; London, Ontario Canada). In the second study, radiolabeled aerosols of flunisolide from a RESPIMAT device, from a RESPIMAT device modified by inclusion of a baffle/impactor in the mouthpiece, and from a conventional MDI with an Inhacort spacer (Boehringer Ingelheim; Ingelheim, Germany).

MEASUREMENTS AND RESULTS

Assessment of the deposition of fenoterol or flunisolide in the lung and oropharynx using gamma scintigraphy. Safety was assessed based on reported adverse effects and spirometry (FEV1, FVC, and peak expiratory flow rate) to detect any paradoxical bronchoconstriction. The RESPIMAT device delivered significantly more fenoterol to the lungs than either an MDI alone or an MDI with Aerochamber (39.2% vs 11.0% and 9.9% of metered dose, respectively; p<0.01). Oropharyngeal deposition of fenoterol from the new device was lower than that from the MDI (37.1% vs 71.7%, respectively; p<0.01). The RESPIMAT device deposited significantly more flunisolide in the lungs compared with MDI plus spacer (44.6% vs 26.4%, respectively; p<0.01), while resulting in similar oropharyngeal deposition (26.2% vs 31.2%, respectively). Introduction of a baffle into the RESPIMAT system reduced lung deposition of flunisolide to 29.5%, and oropharyngeal deposition to 7.8% (p<0.01).

CONCLUSION

The RESPIMAT device may prove to be an effective alternative to MDIs for the administration of inhaled bronchodilators and corticosteroids. The high lung deposition and low oropharyngeal deposition may lead to improved efficacy and tolerability of inhaled medications, especially corticosteroids.

Inhaled flunisolide for acute severe asthma

This randomized, double-blind trial was designed to determine the benefit of high and cumulative doses of flunisolide added to salbutamol in patients with acute asthma in the emergency room (ER). Ninety-four patients who presented to an ER for treatment of an acute exacerbation of asthma were assigned in a randomized, double-blind fashion to receive salbutamol and placebo (n = 47) or salbutamol combined with flunisolide (n = 47). Both drugs were administered successively through a metered-dose inhaler and spacer at 10-min intervals for 3 h (400 microg of salbutamol and 1 mg of flunisolide every 10 min). In both groups, FEV1 and peak expiratory flow rate (PEFR) improved significantly over baseline values (p < 0.01). Results in the flunisolide group were significantly different from those in the placebo group at 90, 120, 150, and 180 min. Data analyzed separately in accord with the duration of the attack before presenting at the ER (< 24 or > or = 24 h) showed that the placebo > or = 24 h group produced a significantly lower FEV1 at 120, 150, and 180 min (p = 0.041) than did the remaining groups. Our data support the theory that high and cumulative doses of inhaled flunisolide administered by metered-dose inhaler with spacer and added to salbutamol are an effective therapy for patients with acute asthma and a prolonged duration of symptoms before ER presentation.

Adrenal function and high dose inhaled corticosteroids for asthma

OBJECTIVE

To investigate effects on adrenal function of fluticasone, a recently released inhaled steroid preparation with lower systemic bioavailability than beclomethasone dipropionate.

METHODS

34 children on high doses (400-909 micrograms/m2/d) of inhaled beclomethasone dipropionate or budesonide were recruited into a double blind, crossover study investigating the effects on adrenal function of beclomethasone and fluticasone propionate, given using a standard spacer (Volumatic). The 24 hour excretion rates of total cortisol and cortisol metabolites were determined at baseline (after a two week run in), after six weeks treatment with an equal dose of beclomethasone, and after six weeks of treatment with half the dose of fluticasone, both given through a spacer device.

RESULTS

The comparison of effects between fluticasone and beclomethasone during treatment periods, although favouring fluticasone in all measured variables, reached significance only after correction for urinary creatinine excretion (tetrahydrocortisol and 5 alpha-tetrahydrocortisol geometric means: 424 v 341 micrograms/m2/d). The baseline data showed adrenal suppression in the children taking beclomethasone (total cortisol geometric means: 975 v 1542 micrograms/d) and a dose related suppression in the children taking budesonide. Suppressed adrenal function in the children who were taking beclomethasone at baseline subsequently improved with fluticasone and beclomethasone during treatment periods.

CONCLUSIONS

Fluticasone is less likely to suppress adrenal function than beclomethasone at therapeutically equivalent doses. The baseline data also support the claim that spacer devices should be used for the administration of high doses of inhaled topical steroids.

The economic aspects of drug delivery in asthma

The need for cost-effective asthma therapy is driven by the high prevalence of asthma as well as the high cost of both medical care and lost productivity through illness. Limited healthcare resources demand proven therapies that maintain sustained disease control. Optimal disease control is the essence of cost effectiveness, but this in turn is dependent on correct drug selection and appropriate drug delivery. Successful treatment depends on delivery of medication to the site of action in the airways. Although there is a substantial number of aerosol delivery systems available, there is considerable confusion as to the most suitable method in different clinical settings, and across different age groups. Optimal drug delivery can be achieved without adding substantially to the overall cost of therapy. Both drugs and delivery systems need to be individualised to the needs of the patients. The early introduction of oral corticosteroids for acute exacerbations has resulted in reduced hospitalisation and shortened illness, providing substantial cost savings. A reduction in the reliance on nebuliser therapy in both the acute and chronic setting will further optimise therapy and reduce costs. We have reviewed the current literature to determine the most cost-effective methods of drug delivery in asthma.

Teaching elderly patients how to use inhalers. A study to evaluate an education programme on inhaler technique, for elderly patients

Elderly patients often receive little or no teaching on the use of their inhalers. This study evaluated a patient teaching programme, designed specifically for elderly people. The sample (n = 27) was taken from patients who were prescribed inhalers and had been admitted to the elderly care wards of an acute provider unit. Individual inhaler technique was assessed, using a simple checklist, both before and after teaching and total scores calculated. Each subject received one to one teaching sessions by a registered nurse on four consecutive occasions that inhaled medication was due, together with an information sheet on inhaler technique. Total scores showed significant improvement; however, improvement on any one action was not found to be significant. Thus patient teaching leads to a significant improvement in inhaler technique; however, further research is necessary to determine whether this improvement is sustained over time. Recommendations for practice are made.

Effect of add-on devices for aerosol drug delivery: deposition studies and clinical aspects

Add-on devices for pressurised metered dose inhalers (MDIs) improve "targeting" of drug to the lungs and can correct for hand-breath dyscoordination. Measurements of drug delivery from add-on devices by gamma scintigraphy have shown that compared to an MDI, oropharyngeal deposition is always reduced, and that lung deposition is generally either increased or unchanged. The total body dose may be reduced by over 80%. Increases in lung deposition may not result in improved bronchodilator response if the top of the dose-response curve has been reached. Add-on devices with one-way valves and mouthpiece or mask may enable asthma to be controlled with a smaller delivered dose of drug than from an MDI, and have proved to be viable lower cost alternatives to the use of nebulizers for delivering high dose bronchodilators to patients with severe acute asthma, and steroids to chronic asthmatics.

Inhalational drug delivery from seven different spacer devices

BACKGROUND

A study was performed to determine in vitro the difference in drug output of seven currently available spacer devices when used with different inhaled medications.

METHODS

A glass multistage liquid impinger (MSLI) was used to determine the amount of disodium cromoglycate (DSCG, 5 mg), salbutamol (100 micrograms), or budesonide (200 micrograms) obtained in various particle size ranges from metered dose inhalers (MDIs) actuated directly into the MSLI or via one of seven different spacer devices; the Fisonair, Nebuhaler, Volumatic, Inspirease, Aerochamber, Aerosol Cloud Enhancer, and Dynahaler.

RESULTS

In particles smaller than 5 microns in diameter the dose of DSCG recovered from the Fisonair and Nebuhaler was 118% and 124%, respectively, of that recovered using the MDI alone. The dose recovered from the smaller volume spacers was 90% (Inspirease), 36% (Aerochamber), 33% (Aerosol Cloud Enhancer), and 21% (Dynahaler) of that from the MDI alone. The Volumatic increased the amount of salbutamol in particles smaller than 5 microns to 117% of that from the MDI, and the Inspirease and Aerochamber spacers decreased it by nearly 50%. The amount of budesonide in small particles recovered after use of the Nebuhaler, Inspirease, and the Aerochamber was 92%, 101%, and 78%, respectively, of that from the MDI alone.

CONCLUSIONS

Under the test conditions used, large volume spacers such as the Fisonair, Nebuhaler, and Volumatic delivered significantly more DSCG and salbutamol than the smaller spacers tested. The differences between spacers were less for budesonide than the other medications studied. This study shows that there are significant differences in the amount of drug available for inhalation when different spacers are used as inhalational aids with different drugs. Spacer devices need to be fully evaluated for each drug prescribed for them.

Efficiency of aerosol medication delivery from a metered dose inhaler versus jet nebulizer in infants with bronchopulmonary dysplasia

The best means for optimal delivery of drugs into lungs of infants with bronchopulmonary dysplasia (BPD) is uncertain. We aimed to measure radio-aerosol deposition of salbutamol by jet nebulizer and metered dose inhalers (MDI) in ventilated and non-ventilated BPD infants. In a randomized, crossover sequence, salbutamol lung deposition was measured using an MDI (2 puffs or 200 micrograms) or sidestream jet nebulizer (5 minutes of nebulization with 100 micrograms/kg) in 10 ventilated (mean birthweight, 1,101 g) and 13 non-ventilated (mean birthweight, 1,093 g) prematurely born infants. Non-ventilated infants inhaled aerosol through a face mask, connected to a nebulizer or an MDI and spacer (Aerochamber). Ventilated infants received aerosol from an MDI + MV15 Aerochamber or a nebulizer inserted in the ventilator circuit. Lung deposition by both methods was low: mean (SEM) from the MDI was 0.67 (0.17)% of the actuated dose, and from the nebulizer it was 1.74 (0.21)% and 0.28 (0.04)% of the nebulized and initial reservoir doses, respectively. Corresponding figures for the ventilated infants were 0.98 (0.19)% from the MDI and 0.95 (0.23)% and 0.22 (0.08)% from the nebulizer. In both groups, and for both methods of delivery, there was marked inter-subject variability in lung deposition and a tendency for the aerosol to be distributed to the central lung regions.

Inhalation of single vs multiple metered-dose bronchodilator actuations from reservoir devices. An in vitro study

Differences in inhalation technique with reservoir or spacer devices may affect metered-dose inhaler (MDI) dose availability to a patient.

PURPOSE

This study examined the effect of single vs multiple actuations of an MDI into reservoir devices on dose delivery of albuterol, with three clinically available reservoir brands.

METHODS

An in vitro lung model simulated inspiration from the MDI reservoir system. Albuterol (Proventil; Schering) was delivered by MDI, with the Monaghan Aerochamber, the Diemolding Healthcare Division (DHD) aerosol cloud enhancer (ACE), and the Schering InspirEase, using standardized volumes and inspiratory flows of 30 L min(-1). The MDI was actuated into each brand of reservoir 1, 2, or 3 times in rapid succession, followed by a single inhalation. Aerosol dose at the reservoir mouthpiece was captured on a cotton filter, dissolved in ethanol, and measured with a spectrophotometer at 278 nm.

RESULTS

For all three brands of reservoir, less accumulated dose of drug is delivered with multiple actuations than with multiple single actuations each followed by inhalation. The total dose in milligrams increased significantly with two multiple actuations compared with one actuation in the Aerochamber and ACE (p<0.01), but not in the InspirEase (p>0.05). The Aerochamber, ACE, and InspirEase delivered a mean total dose (SD) of 0.0264 mg (0.012), 0.0271 mg (0.007), and 0.0136 mg (0.006), respectively, with one actuation compared to 0.0485 mg (0.011), 0.0453 mg (0.013), and 0.0218 mg (0.009) with two multiple actuations. The increase in total dose with three multiple actuations was not significant compared to two actuations for any of the brands tested (p>0.05). Although total dose increased with multiple actuations, a decline in efficiency was seen with two and three multiple actuations, compared to single actuation. The dose delivered per actuation decreased for the Aerochamber, ACE, and InspirEase from 0.0264 mg (0.012), 0.0271 mg (0.007), and 0.0136 mg (0.006) with one actuation, to 0.0243 mg (0.006), 0.0226 mg (0.006), and 0.0109 mg (0.005), respectively, with two multiple actuations, for losses of 8.0%, 16.6%, and 19.9% in dose per actuation for each brand. A further decline in delivery per actuation to 0.0164 mg (0.001), 0.0184 mg (0.004), and 0.0097 mg (0.005) for the 3 brands, respectively, was found with 3 multiple actuations before inhalation. This was a loss of 37.9%, 32.1%, and 28.7% of the dose per single actuation in each brand. There was no significant difference between the Aerochamber and the ACE in dose availability with 1, 2, or 3 actuations, but both of these brands provided significantly more drug than the InspirEase.

CONCLUSION

Maximal aerosol bronchodilator from an MDI reservoir was given by single actuations each followed by a breath. Two rapid actuations followed by a breath will give a significant accumulation of dose with some loss when compared to two single actuations each followed by inhalation. Three multiple actuations led to a loss of approximately one third of the drug dose obtainable with three single actuations each followed by inhalation, for all three brands.

Inhalers and nebulizers: which to choose and why

It is obvious that many factors should be considered when an inhaler is prescribed. Based upon the information discussed above, a rational inhaler strategy could be as follows: (1) Children < or = 5 years and elderly patients are prescribed a spacer with a valve system (and a face mask for the children) for the delivery of all drugs. When they are severely obstructed, some may need a nebulizer. If the patient cannot be taught the correct use of a spacer, a nebulizer should be prescribed. (2) Children > or = 5 years and adults are prescribed a spacer or a Turbuhaler for the administration of inhaled corticosteroids and a dry powder inhaler (preferably multiple dose) or a breath-actuated MDI for other drugs. If these alternatives are not available or the patient prefers, a conventional MDI can be used (preferably not for other corticosteroids than fluticasone propionate) provided that careful tuition is given. Fluticasone dipropionate may be given by DPI, Spacer or MDI. (3) Nebulizers are mainly reserved for severe acute attacks of bronchoconstriction. With this approach, most patients can be taught effective inhaler use with a minimum of instructional time. Finally, it must always be remembered to consider the patient's wish, since prescription of an inhaler which the physician likes but the patient does not is likely to reduce compliance.

Optimizing inhaled drug delivery in patients with asthma

Successful management of asthmatic patients depends on achieving adequate delivery of inhaled drugs to the lung. This assumes particular importance for inhaled corticosteroids where the therapeutic goal should be to achieve a high ratio of airway anti-inflammatory efficacy to local and systemic side effects. The availability of user-friendly inhaler devices requires a critical appraisal of their effectiveness and an evaluation of whether improved lung deposition of anti-asthma drugs translates into improved clinical efficacy. There is evidence to suggest that the routine use of large-volume spacers for inhaled corticosteroids may not be the best first-line option, in that reduced drug delivery is associated with multiple actuations, inhalation delay and the presence of static electricity. Breath-actuated pressurized aerosol devices or dry powder inhaler devices may be a better option for many asthmatic patients, although the efficiency of drug delivery varies considerably between these devices. There is good evidence with a reservoir dry powder inhaler device to show that improved lung deposition translates into better therapeutic response, both in terms of beta 2-agonist and corticosteroid delivery. For inhaled corticosteroids, such as fluticasone propionate and budesonide, there is evidence to show that systemic bioactivity is mainly determined by lung bioavailability rather than gastrointestinal bioavailability, because of the absence of first-pass metabolism of these drugs in the lung. There is also evidence to show that the greater glucocorticoid potency of fluticasone propionate translates directly into greater systemic bioactivity, but not into enhanced efficacy, at doses above 1 mg daily. The use of efficient delivery systems, such as the reservoir dry powder inhaler device, may not only improve control of asthma and compliance with therapy, but may also allow dose reduction ('step-down' therapy) and hence may possibly reduce overall prescribing costs in the long term.

Aerosol deposition in the human lung following administration from a microprocessor controlled pressurised metered dose inhaler

BACKGROUND

Gamma scintigraphy was employed to assess the deposition of aerosols emitted from a pressurised metered dose inhaler (MDI) contained in a microprocessor controlled device (SmartMist), a system which analyses an inspiratory flow profile and automatically actuates the MDI when predefined conditions of flow rate and cumulative inspired volume coincide.

METHODS

Micronised salbutamol particles contained in a commercial MDI (Ventolin) were labelled with 99m-technetium using a method validated by the determination of (1) aerosol size characteristics of the drug and radiotracer following actuation into an eight stage cascade impactor and (2) shot potencies of these non-volatile components as a function of actuation number. Using nine healthy volunteers in a randomised factorial interaction design the effect of inspiratory flow rate (slow, 30 l/min; medium, 90 l/min; fast, 270 l/min) combined with cumulative inspired volume (early, 300 ml; late, 3000 ml) was determined on total and regional aerosol lung deposition using the technique of gamma scintigraphy.

RESULTS

The SmartMist firing at the medium/early setting (medium flow and early in the cumulative inspired volume) resulted in the highest lung deposition at 18.6 (1.42)%. The slow/early setting gave the second highest deposition at 14.1 (2.06)% with the fast/late setting resulting in the lowest (7.6 (1.15)%). Peripheral lung deposition obtained for the medium/early (9.1 (0.9)%) and slow/early (7.5 (1.06)%) settings were equivalent but higher than those obtained with the other treatments. This reflected the lower total lung deposition at these other settings as no difference in regional deposition, expressed as a volume corrected central zone:peripheral zone ratio, was apparent for all modes of inhalation studied.

CONCLUSIONS

The SmartMist device allowed reproducible actuation of an MDI at a preprogrammed point during inspiration. The extent of aerosol deposition in the lung is affected by a change in firing point and is promoted by an inhaled flow rate of up to 90 l/min-that is, the slow and medium setting used in these studies.

A large volume spacer significantly reduces the effect of inhaled steroids on bone formation

Inhaled steroids are increasingly advocated as first line treatment for mild asthma. Some studies suggest that inhaled steroids suppress bone formation as reflected by a fall in plasma osteocalcin. Spacers have been shown to increase the proportion of inhaled aerosol that is deposited in the lungs and to reduce the amount swallowed. We measured plasma osteocalcin levels to determine the effect on bone formation of inhaled beclomethasone dipropionate (BDP) with and without a 750 ml spacer in a double-blind, randomised, placebo-controlled, cross-over study. Twenty-six healthy male volunteers took BDP 500 micrograms (two puffs of Becloforte) together with two puffs of placebo, inhaled twice daily for seven days. One inhaler was taken directly while the other was inhaled through a 750 ml spacer. After a two week washout period, the inhalers were exchanged so that BDP was taken by the alternate route for a further seven days. Fasting plasma osteocalcin levels were measured at 09.00 h before and at the end of each week. After a week of BDP taken directly (without a spacer), osteocalcin levels fell from 11.8 (SEM 0.6) ng/ml to 9.5 (SEM 0.5) ng/ml (p < 0.001). After a week of BDP taken through a spacer, osteocalcin levels fell from 12.1 (SEM 0.5) ng/ml to 11.1 (SEM 0.5) ng/ml (p < 0.001). The fall in osteocalcin when a spacer was used was significantly less than when BDP was taken directly (p < 0.005). This is likely to be because the systemic effects on bone are caused by swallowed rather than inhaled BDP, and this is limited by the use of a spacer. Spacers should be more widely prescribed with inhaled steroids. Further prospective studies are indicated to evaluate whether spacers protect bone mass.

Metered dose inhaler and nebuliser in acute asthma

One hundred and eleven children with acute asthma were studied to compare delivery of terbutaline by either a metered dose inhaler (MDI) with a valved holding chamber or a nebuliser driven by air. Eligible patients were randomised; the MDI group received three puffs (0.75 mg) of terbutaline and the nebuliser group received 2 ml (5.0 mg) terbutaline solution diluted with 2 ml 0.9% saline for inhalation over 10 minutes. Patients were evaluated by spirometry, pulse oximetry, and clinical severity scoring system at baseline and again 15 minutes after the beginning of treatment. The baseline data of the two groups were not significantly different. All parameters of spirometry, except the peak expiratory flow (PEF) for the nebuliser group, and clinical severity score for both groups significantly improved after terbutaline treatment. Compared with the nebuliser group, the MDI group after treatment had better mean (SD) oxygen saturation (SaO2; 96.82 (1.63)% v 95.44 (1.88)%), frequency of oxygen desaturation (23.2% v 47.3%), absolute increase of PEF (32.6 (37.7) l/min v 10.2 (34.7) l/min), and SaO2 (0.54 (1.64)% v -0.47 (1.84)%). There was also a mean (SD) per cent increase of forced expiratory volume in one second (22.9 (21.0)% v 15.4 (16.1)%), PEF (27.7 (38.4)%) v 7.7 (25.1)%), and SaO2 (0.58 (1.72)% v -0.47 (1.93)%). In conclusion, aerosol treatment by MDI (with a valved holding chamber) in this study proved to be superior to nebuliser treatment in terms of SaO2 and some measurements of spirometry. Respiratory therapists working with children with severe asthma should be aware of the possibility of oxygen desaturation, especially when using room air as the driving gas for nebulisation.