Switching from conventional to extrafine aerosol beclomethasone dipropionate therapy in children: a 6-month, open- label, randomized trial

BACKGROUND

In adults with asthma, hydrofluoralkane-134a beclomethasone dipropionate (HFA-BDP) extrafine aerosol provides equivalent asthma control at half the daily dose of conventional chlorofluorocarbon (CFC)-BDP.

OBJECTIVE

We sought to compare the efficacy and tolerability of switching from CFC-BDP to HFA-BDP at half the daily dose in children with stable asthma.

METHODS

This 6-month, open-label, randomized, multicenter study enrolled 520 children aged 5 to 11 years with well-controlled asthma receiving inhaled CFC-BDP or budesonide 200 to 800 microg/d x. (Four hundred fifty-two patients were using doses within the recommended range of 200-400 microg and were analyzed separately.) During a 4-week run-in period, patients used CFC-BDP plus a spacer (CFC-BDP+S) at approximately the same dose as they were using before study entry. Patients were then randomized in a 1:3 ratio to continue on CFC-BDP+S or switch to HFA-BDP Autohaler at half the daily dose.

RESULTS

The change from baseline in morning peak expiratory flow was significantly greater in patients receiving 100-200 microg of HFA-BDP compared with those receiving 200-400 microg of CFC-BDP+S at weeks 7 to 8 (8.5 and 0.4 L/min, respectively; P =.014), with continuing improvement in both groups over 6 months (12.2 and 12.4 L/min, respectively, at month 6). There were no significant differences between treatments in mean change from baseline in FEV(1), percentage of days or nights without asthma symptoms, and daily beta-agonist use over the 6-month treatment period. The proportion of patients who had one or more asthma exacerbations, the incidence of adverse events, and the percentage change from baseline in 24-hour urinary free cortisol levels were similar in the 2 treatment groups.

CONCLUSIONS

This study confirms that asthma control can be well maintained in children when switching from CFC-BDP+S to an HFA-BDP Autohaler at doses as low as 100 to 200 microg/d.

On computational control of flow in airblast atomisers for pulmonary drug delivery

Among different approaches to successful pharmacotherapy the pulmonary drug delivery (PDD) mode plays an increasingly important role. In this paper PDD systems based on air-blast atomisation have been analysed mathematically. In order to allow the bioengineer to estimate the degree of effectiveness of a specific system prototype and to lay the basic principles for design, a conservation-law-based mathematical model is discussed. Key control parameters that allow improvement in the efficiency of the system have been identified and main characteristics of the system have been analysed numerically as functions of these parameters.

Step-down therapy with low-dose fluticasone-salmeterol combination or medium-dose hydrofluoroalkane 134a-beclomethasone alone

BACKGROUND

Options for step-down therapy include use of inhaled corticosteroids alone or in combination with a long-acting beta2-agonist.

OBJECTIVE

We sought to evaluate step-down therapy with a fluticasone propionate-salmeterol (FP-SM) combination administered through a dry powder inhaler (DPI; Advair Diskus) versus a medium dose of hydrofluoroalkane 143a-beclomethasone dipropionate (HFA-BDP) administered through a breath-actuated pressurized metered-dose inhaler (QVAR Autohaler).

METHODS

Thirty-nine patients with uncontrolled moderate-to-severe asthma were treated with 1000 microg of DPI-administered BDP twice daily (DPI-BDP) for 4 weeks and then randomized to 200 microg of HFA-BDP twice daily (n = 20) or 100 microg of FP and 50 microg of SM twice daily (FM-SM; n = 19) for 8 weeks in a double-blind, double-dummy, parallel-group design. We measured the provocative dose of methacholine producing a 20% fall in FEV1 (methacholine PD20) as the primary outcome, with secondary outcomes being lung function, surrogate inflammatory markers, diary card responses, quality of life, and safety.

RESULTS

There was a 0.9 (95% confidence interval, 0.5-1.2) doubling dose improvement in methacholine PD20 comparing asthma before versus after DPI-BDP. HFA-BDP maintained this improvement, whereas FP-SM produced a further significant improvement, amounting to a 1.1 (95% confidence interval, 0.2-2.1) doubling dose difference at 8 weeks for FP-SM versus HFA-BDP. Effects on FEV1, peak expiratory flow, and quality of life (symptoms and emotions) were similar to those on methacholine PD20, with a significant difference between FP-SM and HFA-BDP. Suppression of plasma and urinary cortisol and serum osteocalcin levels occurred with DPI-BDP, but values returned to baseline levels within 1 month of HFA-BDP or FP-SM administration.

CONCLUSION

After high-dose inhaled corticosteroid, stepping down with the combination inhaler conferred further improvements in bronchoprotection, bronchodilatation, and clinical control, but not inflammatory markers, compared with that seen with a medium dose of inhaled corticosteroid.

Reverse water-in-fluorocarbon emulsions for use in pressurized metered-dose inhalers containing hydrofluoroalkane propellants

Pulmonary administration of drugs has demonstrated numerous advantages in the treatment of pulmonary diseases due to direct targeting to the respiratory tract. It enables avoiding the first pass effect, reduces the amount of drugs administered, targets drugs to specific sites and reduces their side effects. Reverse water-in-fluorocarbon (FC) emulsions are potential drug delivery systems for pulmonary administration using pressurized metered-dose inhalers (pMDI). The external phase of these emulsions consists of perfluorooctyl bromide (PFOB, perflubron), whereas their internal phase contains the drugs solubilized or dispersed in water. These emulsions are stabilized by a perfluoroalkylated dimorpholinophosphate (F8H11DMP), i.e. a fluorinated surfactant. This study demonstrates the possibility of delivering a reverse fluorocarbon emulsion via the pulmonary route using a CFC-free pMDI. Two hydrofluoroalkanes (HFAs) (Solkane(R) 134a and Solkane(R) 227) were used as propellants, and various solution (or emulsion)/propellant ratios (1/3, 1/2, 2/3, 1/1, 3/2, 3/1 v/v) were investigated. The insolubility of water (with or without the fluorinated surfactant F8H11DMP) in both HFA 227 and HFA 134a was demonstrated. PFOB and the reverse emulsion were totally soluble or dispersible in all proportions in both propellants. This study demonstrated also that the reverse FC emulsion can be successfully used to deliver caffeine in a homogeneous and reproducible way. The mean diameter of the emulsion water droplets in the pressured canister was investigated immediately after packaging and after 1 week of storage at room temperature. Best results were obtained with emulsion/propellant ratios comprised between 2/3 and 3/2, and with HFA 227 as propellant.

A comparison of the efficacy and tolerability of single doses of HFA 134a albuterol and CFC albuterol in mild-to-moderate asthmatic patients

BACKGROUND

After the signing of the Montreal Protocol in 1987, new propellants for use in pressurized metered-dose inhalers that are non-ozone-depleting have been developed.

OBJECTIVE

This study was designed to compare the efficacy and tolerability of single doses of albuterol/HFA 134a with albuterol/CFC and to demonstrate a dose-response among the different doses of both formulations.

METHODS

A single-center, randomized, double-blind, placebo-controlled, cross-over study. Sixty-three adolescent and adult asthmatic patients were randomized to receive at separate treatment visits single doses via a pressurized metered-dose inhaler of either placebo/hydrofluoroalkane (HFA) 134a; 100 microg, 200 microg, or 400 microg albuterol/HFA 134a; 100 microg or 200 microg albuterol/chlorofluorocarbon (CFC). Triplicate measurements of forced expiratory volume in 1 second (FEV1) were made immediately before dosing and 15 minutes, 30 minutes, 1, 2, 3, 4, 5, and 6 hours postdose. The primary efficacy variables were area under the entire 6-hour FEV1 curve, relative to baseline subtracted from the area above baseline (AUC(0-6)) and peak effect (derived from serial FEV1 measurements).

RESULTS

Analysis of AUC(0-6) and peak effect showed that all doses of albuterol had a significantly greater effect than placebo (HFA 134a propellant). Comparisons of the two formulations at 100 microg and 200 microg showed no difference in AUC(0-6) (100 microg, -0.23 Lhr, P = 0.114 and 200 microg -0.08 Lhr, P = 0.590) or in peak effect, percentage of baseline (100 microg, -1.3%, P = 0.354 and 200 microg, 0.17%, P = 0.902). There were no differences seen among formulations in the incidence of adverse events or with any of the other safety parameters, including electrocardiograms, vital signs, clinical laboratory assessments, and asthma exacerbations.

CONCLUSIONS

The study demonstrated comparability in terms of efficacy and safety between albuterol/HFA 134a and albuterol/CFC.

Albuterol HFA is as effective as albuterol CFC in preventing exercise-induced bronchoconstriction

BACKGROUND

Secondary to the phase-out of chlorofluorocarbons (CFCs), the albuterol (Ventolin, GlaxoSmithKline, Uxbridge, Middlesex, United Kingdom) pressurized metered-dose inhaler (MDI) has been formulated in a non-ozone-depleting propellant, hydrofluoroalkane (HFA) 134a.

OBJECTIVE

To compare the efficacy of albuterol HFA to albuterol CFC and placebo HFA in protecting patients from exercise-induced bronchospasm (EIB).

METHODS

Randomized, double-blind, placebo-controlled, three-way crossover study in patients with documented EIB. Patients (n = 24) aged 18 to 45 years old received albuterol HFA or albuterol CFC, (total dose of 180 microg ex-actuator), or placebo HFA via an MDI, 30 minutes before a standardized exercise challenge. Serial forced expiratory volume in 1 second (FEV1) measurements were made 5 minutes before exercise and 5, 10, 15, 20, 25, 30, and 60 minutes postexercise. The primary outcome measure was the maximum percentage fall in FEV1 over the 60 minutes after exercise.

RESULTS

The adjusted mean maximum percentage falls in FEV1 postexercise for albuterol HFA and CFC groups were 15.4% and 14.9%, respectively. The two formulations were comparable with a treatment difference of -0.5% (P = 0.848; 95% confidence interval, -5.3 to 4.4%). When compared with the fall in FEV1 for placebo (33.7%), both active treatments demonstrated a significantly smaller fall in FEV1 postexercise (P < 0.001). Safety profiles were similar among the three treatment groups.

CONCLUSIONS

The results provide assurance to prescribers that the formulation of albuterol in the non-ozone-depleting propellant HFA 134a has not affected its efficacy in the treatment of EIB in asthmatic patients. Single doses of albuterol HFA and CFC from an MDI are comparable in terms of efficacy and safety on a microgram per microgram basis.

Therapeutic significance of distal airway inflammation in asthma

Inflammation in asthma is not merely confined to the large central airways but also extends to the small peripheral airways. Distal lung inflammation can be observed even in patients with asthma with mild disease and normal spirometric readings. Subjects with asymptomatic asthma can exhibit significant increases in peripheral airway resistance, likely the result of distal lung inflammation. As determined from measurements of eosinophilic and other cellular infiltrates, the inflammatory response in the distal lung can exceed that in the large airways. Nocturnal asthma, a natural model of cyclic asthma worsening, is associated with an increase in nighttime distal lung inflammation, as evidenced by the accumulation of alveolar tissue eosinophils. Distal lung disease appears to increase the risk of recurrent asthma exacerbation, whereas disease-related anatomic changes in the small airways of the distal lung are prominent in fatal asthma. The clinical significance of distal lung disease makes this region an important therapeutic target. Chlorofluorocarbon (CFC)-based preparations of inhaled corticosteroids used to treat airway inflammation produce aerosols of relatively large particle size (approximately 4 microm); such aerosols have poor access to the distal lung. New formulations of inhaled corticosteroids that use hydrofluoroalkane (HFA) propellants can have smaller particle sizes (approximately 1 microm). Extrafine HFA aerosols have better access to the distal lung, with less oropharyngeal deposition. Imaging studies suggest that anti-inflammatory medication delivered as an extrafine aerosol produces beneficial changes in distal lung function. In one study, an HFA formulation of an inhaled corticosteroid reduced air trapping to a greater degree than a CFC formulation of the same corticosteroid. By extending the delivery of anti-inflammatory medication to the distal lung, the new HFA-based corticosteroids have the potential to treat asthma more effectively and at reduced steroid doses.

Evaluation of microencapsulation of a Bifidobacterium strain with starch as an approach to prolonging viability during storage

AIMS

To optimize a spray coating process for the production of encapsulated microspheres containing viable Bifidobacterium cells and to determine whether the readily gelatinized modified starch coating used in this study improved bacterial survival in foods or under acid conditions.

METHODS AND RESULTS

An air inlet temperature of 100 degrees C was demonstrated to be optimal for the spray drying process, as it afforded good drying, low outlet temperatures (45 degrees C) and resulted in less than 1 log reduction in bifidobacteria numbers during drying. Maximum recovery yields of 30% were obtained after optimizing the air aspiration conditions. The average size of the Bifidobacterium PL1-containing starch microparticles was determined by scanning electron microscopy to be of the order of 5 microm. The starch-coated cells did not display any enhanced viability compared with free PL1 cells when exposed to acid conditions for 6 h or in two dry food preparations over 20 d storage at ambient temperature (19-24 degrees C). Determination of 1491 nucleotides of the 16S rRNA gene from PL1 indicated that it shared 97% homology with a previously sequenced Bifidobacterium ruminantium strain.

CONCLUSIONS

Our data demonstrated that, although spray drying is a valuable process for encapsulating bifidobacteria, further work is required to ascertain a more appropriate coating material that will protect this strain against adverse environmental conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

The production of small, uniformly coated microspheres containing viable bifidobacteria using an affordable and industrially convenient process, such as spray drying, has commercial implications for the production of probiotic products. Although popular for use as a coating polymer by the food industry, this study indicated that modified starches might not be suitable for use as an encapsulating material for probiotic strains.

Delivery options and devices for aerosolized therapeutics

Although inhalation is one of the oldest modes of drug delivery, it is currently receiving renewed attention. Prior to 1987, aerosolized therapeutics were delivered via systems that relied on chlorofluorocarbon propellant systems. The subsequent ban on all nonmedical uses of these inert gases stimulated pharmaceutical companies to investigate other propellant systems. Two hydrofluoroalkanes were effective. However, in some instances, the change in propellant required reformulation of the drugs to be delivered. In some cases, bioequivalence could be achieved at lower doses with reduced toxicity. Pressurized metered-dose inhalers (pMDIs) have been used to deliver many types of inhaled therapeutics since the 1960s. Their major limitation is that drug delivery and effectiveness are affected by patient factors, including coordination difficulties and problems related to breathing and breath holding in patients with airway disease. Dry-powder inhalers are being developed to deliver powdered formulations of drugs such as bronchodilators and anti-inflammatory drugs for the treatment of asthma and COPD, and, eventually, proteins, peptides, recombinant products, and gene therapeutics. These devices have been proven to be as efficient as pMDIs in clinical trials. In some cases, they deliver a greater amount of the drug to the lungs. Percentages of the emitted dose deposited in the lungs range from 15 to 40% with the current generation of these devices. Finally, metered-dose liquid inhalers also are under development. Drug deposition in the lung with devices that are currently being tested ranges from 30 to 80% of the emitted dose. The choice of delivery system depends on the effective dose, drug deposition, patient ability, patient acceptance, and cost. Patient education in the correct use of each device is essential to maximize the therapeutic benefit.

Laser-mediated cartilage reshaping with feedback-controlled cryogen spray cooling: biophysical properties and viability

BACKGROUND AND OBJECTIVE

Recent studies have indicated that chondrocyte viability decreases with prolonged or repeated laser irradiation. To optimize laser-mediated cartilage reshaping, the heating process must be finely controlled. In this study, we use high-power Nd:YAG laser irradiation (lambda = 1.32 microm) combined with cryogen spray cooling (CSC) in an attempt to reshape porcine septal cartilage while enhancing chondrocyte viability.

STUDY DESIGN/MATERIALS AND METHODS

Chondrocyte viability was determined after high-power (50 W/cm2) Nd:YAG-mediated cartilage reshaping with and without cryogen spray cooling (CSC) and correlated with dynamic measurements of tissue optical and thermal properties.

RESULTS

After 1.5 to 2.0 seconds of laser exposure, characteristic changes in diffuse reflectance (indicating the onset of accelerated stress relaxation) was observed in both laser only and laser with CSC specimens. After 2 seconds of laser exposure, specimens in both groups retained the curved shape for up to 14 days. After one laser exposure, chondrocyte viability was 94.35 +/- 6.1% with CSC and 68.77 +/- 20.1% (P < 0.05) without CSC. After two laser exposures, a similar trend was observed with CSC (70.18 +/- 16.44%) opposed to without CSC (28 +/- 45%; P < 0.05).

CONCLUSION

CSC during high-power laser irradiation allows rapid heating while minimizing extreme front surface temperature elevations and axial thermal gradients. Laser irradiation with CSC can be used to effectively reshape cartilage tissue with the additional advantage of increasing chondrocyte viability.

The influence of lung deposition on clinical response

Delivery of more drug to the lung may appear to be a desirable goal in the treatment of asthma and chronic obstructive pulmonary disease, since only 10 to 15% of a drug dose administered via a metered dose inhaler (MDI) reaches the lung. However, increasing the dose of most inhaled drugs may only lead to an increase in side effects, since maximal clinical benefit is usually obtained with the currently recommended dosages. Improving the regional deposition of inhaled drugs may be a more effective way of modifying clinical response. Particle size is the most significant determinant of the deposition pattern of inhaled drugs. Optimum drug delivery to the conducting airways occurs with particles ranging from 2.5 to 6 microm; particles <2.5 microm are deposited mainly in the alveoli where they may exert no pharmacodynamic effect and are rapidly absorbed, increasing the risk of systemic adverse events. Delivery devices can be compared by estimating the lung and systemic exposures, taking into account the efficacy and safety dose-response relationships for the drug-device combination. Current devices have profoundly different lung deposition profiles that could affect clinical efficacy when switching devices. Devices that achieve a high lung to systemic ratio for the inhaled drug are preferable.

Low-temperature micronization of a peptide drug in fluid propellant: case study cetrorelix

Aim of this study was to elaborate an efficient method for the micronization of the decapeptide cetrorelix (a GnRH-antagonist), in order to obtain a microsuspension as basis for other pharmaceutical preparations, such as e.g. inhalation aerosols. A modified pearl-mill coupled with a cryostat was used for the micronization of cetrorelix in fluid propellant and operated under different conditions. The obtained cetrorelix suspensions were analyzed for particle size distribution, purity of cetrorelix, and for metal contamination through abrasion from parts of the mill. The method allowed an effective micronization of cetrorelix. The mean particle size of the initial cetrorelix lyophilizate bulk ware was reduced from 52.5 microm (Volume Mean Diameter, VMD) down to 14.9, 6.1 and 3.1 microm, respectively, respectively. The HPLC analysis of all cetrorelix suspensions after micronization did not show signs of decomposition as compared to the initial product. The elementary analysis of the suspensions performed by inductively coupled plasma mass spectrometry revealed a negligible amount of contaminants in the suspension (Zr = max. 0.6 ppm; Fe, Cr, Ni, Ba, below limit of quantification, i.e. < 0.14 ppm). The only appreciable contaminant, Aluminum (Al = 1.1 ppm), was derived from the mechanical capping of aluminum canisters prior to analysis. The Zr determination in the suspension of 0.6 ppm, is still considered to be negligible as compared to the legally tolerated limit of air contamination. By low-temperature micronization in fluid propellant, fine drug suspensions of cetrorelix for pMDIs can be directly manufactured in one-step procedure without destruction of the peptide structure and without appreciable product contamination.

Investigation of some commercially available spacer devices for the delivery of glucocorticoid steroids from a pMDI

Five commercially available spacers were investigated to determine their influence on the percentage of drug retained in the spacer device, percentage fine particle fraction (FPF), percentage deposited in the induction port, mass median aerodynamic diameter (MMAD), and geometric standard deviation (GSD). Betamethasone valerate (BMV) and triamcinolone acetonide (TAA) were used as model drugs in the pressurized metered dose inhaler (pMDI) formulations containing the propellant HFA 134a. The BMV was dissolved in an ethanol/HFA 134a system, and the TAA was suspended in HFA 134a using ethanol as a dispersing agent. The metering chamber volume of the valve was either 50 microl or 150 microl. The spacer devices investigated included the ACE, Aerochamber, Azmacort, Easivent, and Ellipse spacers. Each spacer device was attached to an Andersen Cascade Impactor powered by a vacuum pump. Cascade impaction data were used to derive the percentage drug deposited in the induction port, MMAD, GSD, and FPF. The BMV particles emitted from the spacers were finer than the TAA particles because the dissolved drug precipitated as the cosolvent evaporated. The TAA particles had significantly larger MMADs because many undissolved drug particles were contained within each droplet following actuation. After evaporation of the liquid continuous phase, the suspended drug aggregated to form larger agglomerates than those particles precipitated from the BMV pMDI solution droplets. The addition of a spacer device lowered the MMAD to less than 4.7 microm for particles from both the BMV pMDI solution and the TAA pMDI suspension. The addition of a spacer device also lowered the percentage drug deposited in the induction port. The FPF was significantly increased when a spacer device was used. The MMAD significantly decreased when a spacer device was added for the two model drugs when using the 150-microl metering valves, but the difference was not statistically significant when the 50-microl valves were used (P < .05). The GSD was not influenced by the use of a spacer device. The use of a spacer device will enhance pMDI therapy by reducing the amount of drug deposited in the oropharyngeal region, which will lead to fewer instances of local and systemic side effects. In addition, the spacer devices investigated will allow a higher dose of drug to reach the deep lung, which may permit the use of lower dosage regimens with increased therapeutic efficacy.

Delivery of fenoterol via Respimat, a novel 'soft mist' inhaler. a randomised, double-blind (within device), placebo-controlled, cross-over, dose-ranging study in asthmatic patients

BACKGROUND

The phase-out of chlorofluorocarbons (CFCs) for metered dose inhalers (MDIs) has prompted the development of alternative propellants and the design of propellant-free devices for inhalation therapy.

OBJECTIVE

This study was carried out to determine the dose of fenoterol inhaled from Respimat (RMT), a new propellant-free soft mist inhaler, which is equivalent in terms of efficacy and safety to 1 puff of either 100 or 200 microg fenoterol inhaled from a conventional CFC-MDI (Berotec).

METHODS

Sixty-two asthmatic patients (35 male, 27 female) with a mean baseline FEV(1) of 1.7 liters, corresponding to 55% of the predicted normal value, were randomized at two study centers to 4 of a total of 8 possible treatments: placebo; 12.5, 25, 50, 100, or 200 microg fenoterol via RMT, and 100 or 200 microg fenoterol delivered via the MDI.

RESULTS

Fifty-nine patients completed the study as planned. Results of the therapeutic equivalence test for the primary endpoint, average FEV(1) (AUC(0-6))/6 and for the secondary endpoint, peak FEV(1), showed that the 12.5- and 25-microg fenoterol doses administered via RMT were equivalent to the 100 microg fenoterol dose from the MDI. The 50-, 100- and 200-microg fenoterol doses delivered by RMT did not meet the criterion for therapeutic equivalence with the 100-microg dose from the MDI, and if tested for a difference would have been significantly different in favor of RMT. All 5 RMT fenoterol doses were therapeutically equivalent to the MDI 200-microg fenoterol dose. Headache, reported by 4 patients on test days and 2 patients between test days in those randomized to RMT, was the most common adverse event, but the active treatments were generally well tolerated with no dose-dependent increases in incidence or severity of adverse events observed.

CONCLUSIONS

The results from the study suggest that safe and efficacious bronchodilation can be obtained from single-dose fenoterol administered via RMT. Use of lower absolute doses to obtain a clinically significant improvement in pulmonary function may be possible because of the increased lung deposition achievable with the novel soft mist inhaler.

Comparative in vivo lung delivery of hydrofluoroalkane-salbutamol formulation via metered-dose inhaler alone, with plastic spacer, or with cardboard tube

STUDY OBJECTIVE

To compare the lung delivery of chlorofluorocarbon-free salbutamol via a pressurized metered-dose inhaler (pMDI) alone, a pMDI with a small-volume plastic spacer, and a pMDI with a cardboard tube.

DESIGN

A randomized, single (investigator)-blind, three-way, crossover study.

SETTING

The Asthma and Allergy Research Group, Ninewells Hospital, University of Dundee, Dundee, Scotland, UK.

PARTICIPANTS

Twelve healthy volunteers aged 16 to 65 years.

INTERVENTIONS

The subjects were administered 400 microg of salbutamol via a pMDI alone, via a pMDI plus a small-volume plastic spacer, or via a pMDI plus a cardboard tube.

MEASUREMENTS AND RESULTS

Blood samples for plasma salbutamol concentrations were taken at 5 min, 10 min, and 20 min after inhalation, to measure lung bioavailability as a surrogate for relative lung dose. The addition of the plastic spacer resulted in a significantly higher maximal plasma salbutamol concentration (CMAX) and average plasma salbutamol concentration (CAV) than the pMDI used alone. This amounted to a 1.48-fold (32%) difference (95% confidence interval [CI], 1.03 to 2.13) for CMAX and a 1.42-fold (30%) difference (95% CI, 1.01 to 2.00) for CAV. There was no significant difference in the CMAX or CAV comparing the addition of the cardboard tube with the plastic spacer or the pMDI alone.

CONCLUSIONS

Using a chlorofluorocarbon-free pMDI with a plastic spacer produced statistically, but not biologically, significant greater lung delivery of salbutamol. If a spacer is required for reasons other than increasing delivered drug dose, then the addition of a readily available cardboard tube will fulfill many of the required functions with no expense to the patient.

Optimizing drug delivery to the lung: design of a CFC-free corticosteroid metered-dose aerosol system

The mandatory replacement of chlorofluorocarbons (CFCs) with ozone-friendly propellants, such as hydrofluoroalkanes (HFAs), has provided an opportunity to optimize aerosol design and improve drug delivery to pulmonary tissue. Asthma is an inflammatory disorder of the lungs that appears to affect both small and large airways, so ideally, inhaled corticosteroid should reach both central and peripheral sites. This review considers the development of an aerosol system containing beclomethasone dipropionate in hydrofluoroalkane-134a (HFA) propellant (Qvar, 3M Health Care, Loughborough, UK) designed to target medication delivery throughout the bronchopulmonary tree and to improve the therapeutic ratio (topical efficacy: systemic safety), thereby offering potential clinical benefits to asthma patients.

Factors affecting the efficiency of aerosol therapy with pressurised metered-dose inhalers through plastic spacers

AIM

The main objective of this study was to compare the in vitro delivery of salbutamol from a chlorofluorocarbon(CFC)-propelled pressurised metered-dose inhaler (pMDI) versus a newly developed hydrofluoroalkane(HFA)-propelled pMDI through various spacers. In addition, we aimed to study the effect on bronchodilator response when using an optimal pMDI/spacer combination for aerosol delivery compared to a suboptimal combination.

METHODS

Particle size distribution and output from salbutamol pMDIs containing either CFC propellants (Ventolin) or HFA propellants (Airomir) were measured using a multistage liquid impinger (MSLI) and compared to that through both detergent-coated (non-static) or untreated (static) large volume (Nebuhaler, Volumatic) and small volume (Aerochamber) plastic spacers. Flow-volume curves (FEV1) were obtained from twelve asthmatic children with known significant bronchodilator response (8 males), aged 13-17 years, randomly inhaling salbutamol from a CFC-pMDI through a static spacer (Nebuhaler) and from an HFA-pMDI through a non-static spacer (Nebuhaler).

RESULTS

In vitro output of particles in the respirable range (< 6.8 microns) from HFA-pMDIs was significantly higher than that from CFC-pMDIs using various spacers. Removal of electrostatic charge increased output from CFC- and HFA-pMDIs through all spacers by 17-82%. The mean (SD) bronchodilator response after inhalation of salbutamol from a CFC-pMDI through a static spacer was 7.1% (6.3%) compared to 17.5% (7.9%) after inhalation from an HFA-pMDI through a non-static spacer (p = 0.002).

CONCLUSIONS

Use of a newly developed HFA-propelled pMDI greatly improves drug delivery through spacers compared to a CFC-propelled pMDI. However, electrostatic charge in plastic spacers remains the key determinant limiting delivery of salbutamol from a pMDI through spacers, and can be reduced by soaking the spacer in a household detergent. Using an optimal pMDI/spacer combination leads to a significantly improved bronchodilator response.

Influence of water on the solubility of two steroid drugs in hydrofluoroalkane (HFA) propellants

The objective of this research work was to investigate the influence of water level, temperature, and propellant composition on the solubility of two hydrophobic steroid drugs, triamcinolone acetonide (TAA) and beclomethasone diapropionate (BDP). pMDIs containing TAA or BDP, spiked water, and propellant blend with different ratios of HFA 134a and HFA 227 were prepared. The contents of the prepared pMDIs were filtered through a 0.22 mm Acrodisc, syringe filter into a receiving canister after the pMDIs were equilibrated at 15 degrees C, 25 degrees C, 30 degrees C, and 40 degrees C. The drug concentration in the receiving canisters was determined by HPLC and the drug solubility in the propellant blend was calculated. Also, the drug crystal collected on the filter from the donor pMDIs were characterized by x-ray diffraction. The solubility of TAA and BDP varied with propellant composition at all experimental temperatures investigated. The solubility of TAA and BDP increased as the temperature was increased at all propellant compositions and water levels studied, but decreased as the water level in the propellant system was increased at all compositions and temperatures. The x-ray diffraction results indicated that the water in the propellant system had no significant influence on the crystal characteristics of TAA in HFA propellant system, but had a significant impact on the crystal characteristics of BDP was higher than TAA at all propellant compositions, experimental temperatures and water levels investigated. The solubility of TAA and BDP was not only influenced by propellant composition and storage temperature, but also depended on the water level in the propellant system. As a consequence, the crystallinity of the drugs formulated in HFA propellant was influenced by the temperature, propellant composition and the water level in the propellant system. The impact of these factors on the crystallinity of formulated drugs.

The comparative safety/efficacy ratio of HFA-BDP

As has been discussed in the previous sections of the Supplement, the improved physical characteristics of HFA-BDP extrafine aerosol spray allow BDP to be delivered more efficiently into the large, medium and small airways. This improved delivery has allowed the dose of HFA-BDP to be reduced compared to CFC-BDP and budesonide, whilst maintaining equipotency with fluticasone. However, unlike fluticasone, HFA-BDP does not show a propensity for blood or tissue accumulation when administered with a 12-h dosing interval. Standard tests for assessing effects on the HPA-axis indicate that HFA-BDP extrafine aerosol has a favourable systemic bioactivity profile. Even up to the recommended dose of 800 microg day(-1) HFA-BDP (the highest recommended maximum dose), there appear to be no clinically relevant systemic side effects associated with HFA-BDP (Fig. 8). Thus, viewing the data as a whole, it would seem that, compared to CFC-BDP and alternative inhaled corticosteroids, HFA-BDP in a dose of up to 800 microg day(-1) exhibits a favourable therapeutic ratio.