Comparative physicochemical and pharmacokinetic profiles of inhaled beclomethasone dipropionate and budesonide

Poly(malic acid)-budesonide nanoconjugates embedded in microparticles for lung administration

To improve the therapeutic activity of inhaled glucocorticoids and reduce potential side effects, we designed a formulation combining the advantages of nanoparticles, which have an enhanced uptake by alveolar cells, allow targeted delivery and sustained drug release, as well as limited drug systemic passage, with those of microparticles, which display good alveolar deposition. Herein, a polymer-drug conjugate, poly(malic acid)-budesonide (PMAB), was first synthesized with either 11, 20, 33, or 43 mol% budesonide (drug:polymer from 1:8 to 3:4), the drug creating hydrophobic domains. The obtained conjugates self-assemble into nanoconjugates in water, yielding excellent drug loading of up to 73 wt%, with 80-100 nm diameters. In vitro assays showed that budesonide could be steadily released from the nanoconjugates, and the anti-inflammatory activity was preserved, as evidenced by reduced cytokine production in LPS-activated RAW 264.7 macrophages. Nanoconjugates were then embedded into microparticles through spray-drying with L-leucine, forming nano-embedded microparticles (NEMs). NEMs were produced with an aerodynamic diameter close to 1 µm and a density below 0.1 g.cm-3, indicative of a high alveolar deposition. NEMs spray-dried with the less hydrophobic nanoconjugates, PMAB 1:4, were readily dissolved in simulated lung fluid and were chosen for in vivo experiments to study pharmacokinetics in healthy rats. As it was released in vivo from NEMs, sustained distribution of budesonide was obtained for 48 h in lung tissue, cells, and lining fluid. With high loading rates, modulable release kinetics, and low cytotoxicity, these nanoconjugates delivered by NEMs are promising for the more efficient treatment of pulmonary inflammatory diseases.

Thermodynamic and Structural Study of Budesonide-Exogenous Lung Surfactant System

The clinical benefits of using exogenous pulmonary surfactant (EPS) as a carrier of budesonide (BUD), a non-halogenated corticosteroid with a broad anti-inflammatory effect, have been established. Using various experimental techniques (differential scanning calorimetry DSC, small- and wide- angle X-ray scattering SAXS/WAXS, small- angle neutron scattering SANS, fluorescence spectroscopy, dynamic light scattering DLS, and zeta potential), we investigated the effect of BUD on the thermodynamics and structure of the clinically used EPS, Curosurf®. We show that BUD facilitates the Curosurf® phase transition from the gel to the fluid state, resulting in a decrease in the temperature of the main phase transition (Tm) and enthalpy (ΔH). The morphology of the Curosurf® dispersion is maintained for BUD < 10 wt% of the Curosurf® mass; BUD slightly increases the repeat distance d of the fluid lamellar phase in multilamellar vesicles (MLVs) resulting from the thickening of the lipid bilayer. The bilayer thickening (~0.23 nm) was derived from SANS data. The presence of ~2 mmol/L of Ca2+ maintains the effect and structure of the MLVs. The changes in the lateral pressure of the Curosurf® bilayer revealed that the intercalated BUD between the acyl chains of the surfactant's lipid molecules resides deeper in the hydrophobic region when its content exceeds ~6 wt%. Our studies support the concept of a combined therapy utilising budesonide-enriched Curosurf®.

Comparative effectiveness and safety of inhaled corticosteroid plus long-acting β2-agonist fixed-dose combinations vs. long-acting muscarinic antagonist in bronchiectasis

BACKGROUND

This study aimed to evaluate the effectiveness and safety of fixed-dose combination (FDC) inhaled corticosteroids/long-acting β2-agonists (ICS/LABA) in bronchiectasis.

RESEARCH DESIGN AND METHODS

A retrospective cohort study analyzed electronic medical records of bronchiectasis patients initiating ICS/LABA FDC or LAMA between 2007 and 2021. All bronchiectasis diagnoses were made by radiologists using high-resolution computed tomography.

RESULTS

Of the 1,736 patients, 1,281 took ICS/LABA FDC and 455 LAMA. Among the 694 propensity score matched patients, ICS/LABA FDC had comparable outcomes to LAMA, with HRs of 1.22 (95% CI 0.81-1.83) for hospitalized respiratory infection, 1.06 (95% CI 0.84-1.33) for acute exacerbation, and 1.06 (95% CI 0.66-1.02) for all-cause hospitalization. Beclomethasone/formoterol (BEC/FOR) or budesonide/formoterol (BUD/FOR) led to a lower risk of acute exacerbation compared to fluticasone/salmeterol (FLU/SAL) (BEC/FOR HR 0.59, 95% CI 0.43-0.81; BUD/FOR HR 0.68, 95% CI 0.50-0.93). BEC/FOR resulted in lower risks of hospitalized respiratory infection (HR 0.48, 95% 0.26-0.86) and all-cause hospitalization (HR 0.55, 95% 0.37-0.80) compared to FLU/SAL.

CONCLUSION

Our findings provide important evidence on the effectiveness and safety of ICS/LABA FDC compared with LAMA for bronchiectasis. BEC/FOR and BUD/FOR were associated with better outcomes than FLU/SAL.

Oromucosal precursors of in loco hydrogels for wound-dressing and drug delivery in oral mucositis: Retain, resist, and release

Oromucosal films and tablets were developed as multifunctional biomaterials for the treatment of oral mucositis. These are intended to function as a hybrid, performing as a controlled drug delivery system and as a wound-dressing device. The dosage forms are precursors for in loco hydrogels that are activated by the saliva. An anti-inflammatory and anesthetic activity is attained from budesonide tripartite polymeric nanoparticles and lidocaine, while the polymeric network allows the protection and cicatrization of the wound. Different biomaterials and blends were investigated, focusing on the capacity to retain and resist on-site, as well as achieve a long-lasting controlled release. As the limiting factor, the choice was made according to the films' results. A polymer mix of Methocel™ K100M and Carbopol® (974P, EDT 2020, or Ultrez 10) blends were used. Overall, regrading critical factors, Carbopol® increased films' elasticity and flexibility, mucoadhesion, and the strength of the hydrogels, while higher concentrations led to thicker, more opaque, and lower strain resistance products. Whereas 974P and Ultrez 10 performed similarly, EDT 2020 led to uniformity problems and weaker films, hydrogels and bioadhesion. The optimized products were enhanced with sodium hyaluronate and drug-loaded for further characterization. Concerning the dosage form, the films' hydrogels were more resilient, while the tablets had higher mucoadhesiveness and longer swelling. Although through different networks and mechanisms, both dosage forms and grades revealed similar release profiles. A Case II time-evolving stereoselectivity for the 22R and 22S budesonide epimers was found, and Fickian-diffusion for lidocaine. Ultimately, the developed formulations show great potential to be used in OM management. Both of the selected grades at 0.6% displayed excellent performance, while Ultrez 10 can be preferable for the films' production due to its lower viscosity before neutralization and higher after activation. Where the tablets are easier to produce and offer better adhesion, the films are more customizable post-production and have higher rheological performance for wound-dressing.

Quantitative Assessment of Pulmonary Targeting of Inhaled Corticosteroids Using Ex Vivo Receptor Binding Studies

The goal of locally acting inhaled corticosteroids is to achieve distinct pulmonary effects with reduced systemic side effects. The present work using an ex vivo receptor binding model in rats was interested in assessing pulmonary targeting for several commercially available corticosteroids by monitoring receptor occupancies in the lung and systemic organs (liver, kidney, spleen, and brain) after intravenous (IV) injection or intratracheal (IT) instillation of a dry powder administration at a dose of 100 μg/kg. Pulmonary targeting, defined as the difference in cumulative receptor occupancies (AUC_E) between the lung and kidney after pulmonary delivery, differed across the investigated corticosteroids (ΔAUC_E range, 33 ± 46 to 143 ± 52% *h) with the highest degree found for corticosteroids with high systemic clearance and pronounced lipophilicity (presumably allowing a long pulmonary residence time). Additionally, this study demonstrated differences in the receptor occupancies across systemic organs. Using kidney receptor occupancies as the comparator, liver receptor occupancies were reduced (ΔAUC_E range: - 157 ± 43 to 178 ± 42% *h) after IV and IT administration for corticosteroids with high intrinsic clearance, while they were increased for corticosteroid prodrugs due to hepatic activation. Spleen receptor occupancies were increased after IT (ΔAUC_E range: 33 ± 35 to 135 ± 28% *h), but not after IV administration. This was especially true for slowly dissolving drugs. Reduced brain uptake was also observed for ciclesonide (CIC) and des-ciclesonide (desCIC), two compounds previously not investigated. In summary, ex vivo receptor binding studies represent a powerful tool to assess the fate of ICSs.

Management of severe COPD exacerbations: focus on beclomethasone dipropionate/formoterol/glycopyrronium bromide

The major determinant of the decline in lung function, quality of life, and the increased mortality risk in patients with COPD is represented by severe acute exacerbations of the disease, that is, those requiring patients’ hospitalization, constituting a substantial social and health care burden in terms of morbidity and medical resource utilization. Different long-term therapeutic strategies have been proposed so far in order to prevent and/or reduce the clinical and social impact of these events, the majority of which were extrapolated from trials initially focused on the effect of long-acting muscarinic antagonist and subsequently on the efficacy of long-acting β2-agonists in combination or not with inhaled corticosteroids. The option to employ all three classes of molecules combined, despite the limited amount of evidence in our possession, represents a choice currently proposed by international guidelines; however, current recommendations are often based mainly on observational studies or on the results of secondary outcomes in randomized controlled trials. The present narrative review evaluates the available trials that investigated the efficacy of inhaled therapy to prevent COPD exacerbations and especially severe ones, with a particular focus on beclomethasone dipropionate/formoterol/glycopyrronium bromide fixed dose combination, which is the first treatment that comprises all the three drug classes, specifically tested for the prevention of moderate and severe COPD exacerbations.

Ciclesonide: A Pro-Soft Drug Approach for Mitigation of Side Effects of Inhaled Corticosteroids

Inhaled corticosteroids are used as one of the first-line drug therapy in patients with asthma. However, their long-term use is associated with various oropharyngeal and systemic side and adverse effects. Design of pro-soft drug is one of the strategies, which was adopted in the design of ciclesonide for mitigation of side effects usually observed with the use of inhaled corticosteroids. Ciclesonide, a pro-soft drug, is converted to an active metabolite desisobutyryl-ciclesonide in the lungs. The anti-inflammatory effect of desisobutyryl-ciclesonide is much higher than ciclesonide, and therefore, the local effect of the metabolite is higher with lower systemic side effects. Ciclesonide has favorable pharmacokinetic and pharmacodynamic properties as inhaled corticosteroid including low oral bioavailability, high plasma protein binding and rapid systemic clearance, high pulmonary deposition and distribution and long pulmonary residence duration. These advantageous properties make ciclesonide a very effective treatment option with low side effects. Various clinical studies support safety and efficacy of ciclesonide use in mild, moderate, and severe asthma patients.

Oral prolonged release beclomethasone dipropionate and prednisone in the treatment of active ulcerative colitis: results from a double-blind, randomized, parallel group study

OBJECTIVES

Double-blind study comparing efficacy and safety of the topically acting corticosteroid beclomethasone dipropionate (BDP) to prednisone (PD) in patients with active, mild-to-moderate ulcerative colitis (UC).

METHODS

Overall, 282 patients were randomized to receive BDP-prolonged release tablets 5 mg once daily for 4 weeks and then every other day for an additional 4 weeks or oral PD 40 mg once daily for the initial 2 weeks tapered of 10 mg every 2 weeks during the 8-week study period. Efficacy end point was the non-inferiority of BDP vs. PD in terms of Disease Activity Index (DAI) score <3 or reduction by at least 3 points for patients with a baseline DAI ≥7 at week 4. Safety end point was the proportion of patients with steroid-related adverse events (AEs) and cortisol <150 nmol/l at week 4.

RESULTS

DAI response rates at week 4 were 64.6% and 66.2% with BDP and PD, respectively, demonstrating non-inferiority of BDP vs. PD (delta: -1.56; 95% confidence interval (CI) -13.00-9.88, P=0.78). Patients with steroid-related AEs and cortisol <150 nmol/l at week 4 were 38.7% in the BDP group and 46.9% in the PD group (P=0.17 between groups). No safety signals were observed in both the groups.

CONCLUSIONS

BDP was non-inferior to PD in the treatment of active UC, with a good safety profile in both the groups.

Inhaled corticosteroid use in HIV-positive individuals taking protease inhibitors: a review of pharmacokinetics, case reports and clinical management

As a consequence of inhibition of the hepatic cytochrome P450 3A4 isozyme, treatment with HIV protease inhibitors can result in significant drug-drug interactions. One noteworthy interaction is between protease inhibitors and inhaled or intranasal corticosteroids. This interaction can result in adrenal insufficiency and iatrogenic Cushing's syndrome (with symptoms such as rapid weight gain, obesity, facial hirsutism and swelling), as well as hypertension, osteoporosis and decreased CD4 cell count. In this paper, we review and unite pharmacokinetic data, case reports and current research regarding this drug-drug interaction in order to suggest options for the clinical management of HIV-positive patients requiring treatment with protease inhibitors and inhaled or intranasal corticosteroids.

Prediction of environmental concentrations of glucocorticoids: the River Thames, UK, as an example

Synthetic glucocorticoids (GCs) are consumed in large amounts as anti-inflammatory and immunosuppressive drugs worldwide. Based on what has been learnt from studies of other human pharmaceuticals, they are likely to be present in the aquatic environment. However, to date, information on the environmental concentrations of GCs is very limited. The situation is complicated by the fact that a considerable number of GCs are in everyday use in most developed countries. Hence, obtaining a full picture of GC concentrations in the aquatic environment using the traditional analytical chemistry approach would be time-consuming and expensive. Thus, we took a modelling approach to predict the total environmental concentration of all synthetic GCs (consisting of 28 individual GCs) in the River Thames, as a first step in risk assessment of these drugs. Using reliable data on consumption, the LF2000-WQX model predicts mean concentrations up to 30 ng/L of total GCs in surface water as a best case scenario when the lowest excretion and highest removal rates in sewage treatment works were used, whereas mean concentrations up to 850 ng/L were predicted when the highest excretion and lowest removal rates are considered. We also present the 10th and 90th percentile concentrations (which indicate the likely range of concentrations seen from high flow to low flow conditions in the river) of the highest and lowest consumed GCs, to show the spatial and temporal variations of the concentrations of individual GCs. These data probably provide reliable estimates of the likely range of concentrations of GCs in a typical river impacted by effluent from many sewage treatment plants. Results also identify the hot spots where field studies on fish could be focused. To determine if aquatic organisms face any threat from GCs, laboratory toxicity studies should be conducted using concentrations similar to those reported here.

Biophysical interaction between corticosteroids and natural surfactant preparation: implications for pulmonary drug delivery using surfactant a a carrier

Intratracheal administration of corticosteroids using a natural pulmonary surfactant as a delivery vehicle has recently received significant attention in hopes of treating premature newborns with or at high risk for chronic lung disease. As a new practice, both the surfactant preparation used as the carrier and the corticosteroid delivered as the anti-inflammatory agent, and their mixing ratios, have not been standardized and optimized. Given the concern that corticosteroids delivered via a pulmonary surfactant may compromise its surface activity and thus worsen lung mechanics, the present study was carried out to characterize the biophysical interaction between a natural surfactant preparation, Infasurf, and two commonly used inhaled corticosteroids, budesonide and beclomethasone dipropionate (BDP). Based on surface activity measurements by the Langmuir balance and lateral film structure studied by atomic force microscopy, our findings suggest that when Infasurf is used as a carrier, a budesonide concentration less than 1 wt% of surfactant or a BDP concentration up to 10 wt % should not significantly affect the biophysical properties of Infasurf, thus being feasible for pulmonary delivery. Increasing corticosteroid concentration beyond this range leads to early collapse of the surfactant film due to increased film fluidization. Our study further suggests that different affinities to the surfactant films are responsible for the different behavior of budesonide and BDP. In addition to the translational value in treating chronic lung disease, this study may also have implications in inhaled steroid therapy to treat asthma.

Effect of AeroChamber Plus™ on the lung and systemic bioavailability of beclometasone dipropionate/formoterol pMDI

AIM

To assess the effect of AeroChamber Plus™ on lung deposition and systemic exposure to extra-fine beclometasone dipropionate (BDP)/formoterol (100/6 µg) pMDI (Foster®). The lung deposition of the components of the combination given with the pMDI was also evaluated using the charcoal block technique.

METHODS

Twelve healthy male volunteers received four inhalations of extra-fine BDP/formoterol (100/6 µg) using (i) pMDI alone, (ii) pMDI and AeroChamber Plus™ and (iii) pMDI and charcoal ingestion.

RESULTS

Compared with pMDI alone, use of AeroChamber Plus™ increased the peak plasma concentrations (C(max)) of BDP (2822.3 ± 1449.9 vs. 5454.9 ± 3197.1 pg ml(-1)), its active metabolite beclometasone 17-monopropionate (17-BMP) (771.6 ± 288.7 vs. 1138.9 ± 495.6 pg ml(-1)) and formoterol (38.4 ± 17.8 vs. 54.7 ± 20.0 pg ml(-1)). For 17-BMP and formoterol, the AUC(0,30 min), indicative of lung deposition, was increased in the AeroChamber Plus™ group by 41% and 45%, respectively. This increase was mainly observed in subjects with inadequate inhalation technique. However, use of AeroChamber Plus™ did not increase the total systemic exposure to 17-BMP and formoterol. Results after ingestion of charcoal confirmed that AUC(0,30 min) can be taken as an index of lung bioavailability and that more than 30% of the inhaled dose of extra-fine BDP/formoterol 100/6 µg was delivered to the lung using the pMDI alone.

CONCLUSIONS

The use of AeroChamber Plus™ optimizes the delivery of BDP and formoterol to the lung in subjects with inadequate inhalation technique. The total systemic exposure was not increased, supporting the safety of extra-fine BDP/formoterol pMDI with AeroChamber Plus™.

Serum Fructosamine, Total Cholesterol, and High-Density Lipoprotein in Children with Asthma during Glucocorticoid Treatment

Background/Aims. Glucocorticoids may have adverse effects on carbohydrate and lipid metabolism. The present study was conducted to investigate possible effects on carbohydrate and lipid metabolism of inhaled and oral glucocorticoids in children with asthma. Methods. Two randomised controlled trials with blinded crossover designs were performed. Active treatment was 400  μ g inhaled budesonide or 5 mg prednisolone orally daily during one week. The budesonide trial included 17 and the prednisolone trial 20 school children. Serum fructosamine, total cholesterol and high-density lipoprotein were assessed. Results. Serum fructosamine was increased during active treatment (prednisolone 252.3  μ M versus placebo 247.3  μ M; P = 0.03 and budesonide 228.1  μ M versus no treatment 223.1  μ M; P = 0.02). Total cholesterol and high-density lipoprotein were not statistically significantly increased. Conclusion. Short-term treatment with oral prednisolone and inhaled budesonide may adversely affect mean blood glucose concentration. Possible long-term consequences require further investigations.

Cortisol suppression as a surrogate marker for inhaled corticosteroid-induced growth retardation in children

Exposure of inhaled corticosteroids (ICSs) in pediatrics results in adrenal suppression and growth inhibition. The objective of this study was to assess the relationship of ICS mediated growth retardation with cortisol suppression in asthmatic children. A meta-analysis approach was performed with 33 published articles. Growth velocity (GV) data were obtained from the literature for evaluation of growth. Cumulative cortisol suppression within 24h (CCS%) was calculated at steady state with a validated algorithm. Consolidated GV and CCS% data were employed for model development. A linear mixed effects model was developed to adequately describe the relationship between GV and CCS%. No impact of tested covariates was observed. Population estimate of the rate of change in GV was -0.06cm/year/CCS% (12.7%, coefficient of variation) for both stadiometry and knemometry methods. However, GV from stadiometry is expected to be approximately three fold higher than that from knemometry when cortisol suppression was not presented. The final model was evaluated with posterior predictive check and pattern check approaches. The results from this study elucidate CCS% as an excellent predictor of ICS mediated growth retardation in asthmatic children.

Budesonide/formoterol: a review of its use as maintenance and reliever inhalation therapy in asthma

The use of combination budesonide/formoterol dry powder inhaler (Symbicort Turbuhaler) for both daily maintenance therapy and as-needed relief of breakthrough symptoms using a single inhaler is a new approach to asthma management that is indicated in patients with persistent asthma not adequately controlled by conventional regimens using reliever therapy with a short-acting beta(2)-adrenoceptor agonist alone. The administration of additional corticosteroid with each reliever inhalation in response to symptoms is expected to provide improved control of airway inflammation.Budesonide/formoterol maintenance and reliever therapy reduced the risk of severe asthma exacerbations compared with conventional regimens using a short-acting beta(2)-adrenoceptor agonist alone as reliever therapy in the majority of trials, while providing similar or better daily asthma control than higher fixed maintenance doses of budesonide or inhaled corticosteroid/long-acting beta(2)-adrenoceptor agonist combination therapy in patients with generally moderate to severe, uncontrolled, persistent asthma. The strategy offers the convenience of a single inhaler and simplifies treatment by providing immediate additional anti-inflammatory medication in response to asthma symptoms and immediate step-down when symptoms abate. The improved efficacy, with respect to exacerbation prevention, observed with budesonide/formoterol maintenance and reliever therapy in all double-blind comparative trials was achieved with a lower mean daily dose of inhaled corticosteroid or with fewer daily inhalations of reliever medication. Budesonide/formoterol maintenance and reliever therapy was well tolerated with an incidence of adverse events similar to that with conventional regimens. Therefore, it offers a new approach to therapy in patients with uncontrolled, persistent asthma; providing improved efficacy with a lower overall drug load.

Inhaled corticosteroids in children with asthma: pharmacologic determinants of safety and efficacy and other clinical considerations

The role of inhaled corticosteroids (ICS) in the treatment of childhood asthma has been well established. An ideal corticosteroid should demonstrate high pulmonary deposition and residency time, in addition to a low systemic bioavailability and rapid systemic clearance. The lung depositions of the ICS have been compared, with beclomethasone (beclometasone)-hydrofluoroalkane (HFA) and ciclesonide showing the highest lung deposition. Lung deposition is influenced by not only the inhalation device and type of propellant (HFA or chlorofluorocarbon), but also by whether the aerosol is a solution or suspension, and the particle size of the respirable fraction. Pulmonary residency time increases when budesonide and des-ciclesonide undergo reversible fatty acid esterification. The bioavailability of the drug depends on the oral bioavailable fraction and the amount absorbed directly from the pulmonary vasculature. The clearance rate of des-ciclesonide is very high (228 L/h), increasing its safety profile by utilizing extra-hepatic clearance mechanisms. Both des-ciclesonide and mometasone have a high protein binding fraction (98-99%). The volume of distribution (Vd) is proportional to the lipophilicity of the drug, with the Vd of fluticasone being 332L compared with 183L for budesonide. Increasing the Vd will also increase the elimination half-life of a drug. The pharmacodynamics of ICS depend on both the receptor binding affinity and the dose-response curve. Among the ICS, fluticasone and mometasone have the highest receptor binding affinity (1800 and 2200, respectively), followed by budesonide at 935 (relative to dexamethasone = 100). Compared with other nonsteroid asthma medications (long-acting beta-agonists, theophylline, and montelukast) ICS have proven superiority in improving lung function, symptom-free days, and inflammatory markers. One study suggests that early intervention with ICS reduces the loss in lung function (forced expiratory volume in 1 second) over 3 years. Whether airway remodeling is reduced or prevented in the long term is unknown. Potential adverse drug effects of ICS include adrenal and growth suppression. While in low-to-medium doses ICS have shown little suppression of the adrenal pituitary axis, in high doses the potential for significant adrenal suppression and adrenal crisis exists. Several longitudinal studies evaluating the effect of ICS on growth have shown a small decrement in growth velocity (approximate 1-2 cm) during the first year of treatment. However, when investigators followed children treated with budesonide for up to 10 years, no change in target adult height was noted. In conclusion, the development of optimal delivery devices for young children, as well as optimizing favorable pharmacokinetic properties of ICS should be priorities for future childhood asthma management.

Pharmacokinetic and pharmacodynamic properties of inhaled ciclesonide

Inhaled corticosteroids are recommended first-line therapy for persistent asthma of all severities; however, oropharyngeal and systemic adverse events can be a concern. Inhaled corticosteroids exert their therapeutic and adverse effects by interacting with glucocorticoid receptors within and outside the lungs, respectively. Ciclesonide is a novel inhaled corticosteroid that possesses a unique pharmacokinetic and pharmacodynamic profile. Ciclesonide is inactive itself and converted to its pharmacologically active metabolite, desisobutyryl-ciclesonide, in the target organ, the lungs. Pulmonary activation combined with low oral deposition may minimize oropharyngeal adverse events, and low oral bioavailability, rapid clearance, and high protein binding may reduce systemic exposure. In addition, high pulmonary deposition due to the highly respirable particles, combined with the potential for prolonged lung retention via lipid conjugation, provides for effective therapeutic action.

Two-dimensional and three-dimensional imaging show ciclesonide has high lung deposition and peripheral distribution: a nonrandomized study in healthy volunteers

Drug deposition is an important factor that contributes to safety and efficacy outcomes of inhaled steroid therapy. Ciclesonide is a nonhalogenated, inhaled corticosteroid under investigation for the treatment of asthma. Therefore, this study was performed to assess lung deposition of ciclesonide. Technetium-99m (99mTc)-labeled ciclesonide (where the 99mTc-label is physically dissolved in the ciclesonide-hydrofluoroalkane [HFA] solution aerosol) inhaled by healthy volunteers was analyzed by two-dimensional (2-D) and three-dimensional (3-D) imaging to determine lung deposition. Six healthy volunteers inhaled one puff of 40 microg (exactuator, equivalent to 50 microg ex-valve) ciclesonide for 2-D imaging, and two healthy volunteers inhaled 10 puffs of 40 microg ciclesonide for 2-D and 3-D imaging. The ciclesonide aerosol was administered via metered-dose inhaler (MDI) containing HFA-134a as propellant. The ex-actuator mean (+/- standard deviation) deposition of ciclesonide in the lungs was higher (52% +/- 11%) than in the mouth/pharynx (38% +/- 14%). Two-dimensional and 3-D imaging showed that ciclesonide reached all regions of the lung. Mean percent deposition in peripheral regions (47% and 34%) was higher than in lower central regions (17% and 30%), as revealed by 3-D and 2-D imaging, respectively. Inhalation of up to 400 microg of ciclesonide produced no drug-related side effects. In conclusion, ciclesonide administered via metered-dose inhaler using HFA-134a as a propellant provided high lung deposition (>50%), greater distribution throughout peripheral regions of the lungs, and relatively low oropharyngeal deposition.

Comparative pharmacology, bioavailability, pharmacokinetics, and pharmacodynamics of inhaled glucocorticosteroids

A comparison of the pharmacodynamics and pharmacokinetics of inhaled corticosteroids is necessary for their assessment. A good knowledge of these two aspects allows the optimization of efficacy and safety.The currently available inhaled corticosteroids already show some of the desired PK/PD parameters. The local adverse effects are decreased as soon as the inhaled corticosteroid is administered as an inactive prodrug or shows a bet-ter lung deposition. HFA-MDI beclomethasone dipropionate (BDP) and ciclesonide are two agents that illustrate this. Low oral bioavailability, rapid systemic clearance, and high plasma protein binding can minimize systemic adverse effects. Mometasone furoate, ciclesonide, and fluticasone propionate possess those characteristics. The pulmonary efficacy is maximized by high lung deposition and long pulmonary residence times. This effect can be achieved by slow dissolution in the lungs, as is the case for fluticasone propionate or lipid conjugation and has been shown for budesonide and ciclesonide. Furthermore, the lung deposition depends on the inhalation device, the particle size, and the inhalation technique. Therefore,improvement in the design of MDIs, DPIs, and nebulizers, and the development of more effective drug particles will lead to an optimized pulmonary targeting. Much progress has been made in the treatment of asthma. The available inhaled corticosteroids show a high safety profile and a good pulmonary selectivity. Development of newer compounds showed that improvement is possible as the result of a complete understanding of the PK/PD concepts. However,the introduction of further improved formulations with a better efficacy/safety profile will be difficult and protracted because the existing drugs are already highly efficient.

Budesonide-formoterol (inhalation powder) in the treatment of COPD

The budesonide-formoterol dry powder inhaler (Symbicort Turbuhaler 160/ 4.5-640/18 microg/day) contains the long-acting beta2-adrenoreceptor agonist formoterol and the inhaled corticosteroid budesonide. Two large, 12-month trials examined the effect of budesonide-formoterol 160/4.5 microg twice daily in COPD patients who met these criteria. The studies were identical, except one in which the patients had received oral prednisolone 30 mg/ day and had inhaled formoterol 4.5 microg twice daily for 2 weeks before randomization. In terms of the FEV1, budesonide-formoterol produced an effect greater than that of both budesonide alone and formoterol alone reported in previous studies. The combination was generally more effective than either of the components in terms of peak expiratory flow, symptoms, and exacerbations. These advantages of the combination over those of either budesonide alone or formoterol alone were quite consistent. Improving lung function and decreasing symptoms significantly, budesonide-formoterol combination therapy provides significant clinical improvements in COPD, despite the limited reversibility of impaired lung function in the disease.

[The therapeutic index in asthma: how should it be defined?]

INTRODUCTION

The therapeutic index (efficacy/tolerance or benefit/risk ratio) is a major determinant of treatment decisions in asthma.

METHODS

For the numerator, the therapeutic index depends on efficacy (maximal effect) and not potency (dose-response relationship). With regard to the denominator, several pharmacological factors influence the occurrence of side-effects, the acceptability of which also has to be considered.

RESULTS

In asthma, some strategies have a more favourable therapeutic index than others;e.g additional treatment (long acting beta2 agonists, leukotriene receptor antagonists, theophylline) to inhaled corticosteroids instead of doubling the dose of the latter. Conversely, it is extremely difficult to compare the therapeutic indices of different molecules of inhaled corticosteroids.

CONCLUSIONS

The potential risk of systemic side effects with long-term administration of high doses of inhaled corticosteroids suggests the need to seek the minimal effective dose.

Budesonide/formoterol: a review of its use in asthma

Budesonide and formoterol have been combined in a single dry powder device, Symbicort Turbuhaler (budesonide/formoterol 160/9-640/18 microg/day), in an effort to simplify asthma management. The efficacy of budesonide/formoterol as maintenance therapy in patients with asthma has been examined in several randomised studies.Twice-daily budesonide/formoterol was significantly more effective than an equivalent or higher daily dose of budesonide alone or high-dose fluticasone propionate alone at improving peak expiratory flow (PEF) in adults with predominantly moderate persistent asthma. Symptom control and the risk of mild exacerbations were significantly improved versus budesonide alone. Moreover, budesonide/formoterol appeared to be as effective as concurrent therapy with equivalent dosages of budesonide and formoterol administered via separate inhalers in adults with moderate persistent asthma. Budesonide/formoterol administered once daily was as effective as twice-daily administration (equivalent daily doses) and more effective than once-daily budesonide in adults with moderate persistent asthma. Twice-daily budesonide/formoterol significantly improved PEF compared with budesonide in paediatric patients with asthma. Adjustable maintenance dosing with budesonide/formoterol was associated with significantly less study drug use than fixed dosing with budesonide/formoterol in adults with predominantly mild or moderate persistent asthma. In two of three studies (all longer than 4 months' duration), the risk of exacerbations was significantly lower with adjustable than with fixed dosing, but no difference was detected in four short-term studies. Symptom severity was maintained or improved in most patients receiving either treatment regimen. In adults with moderate-to-severe persistent asthma, adjustable maintenance dosing with budesonide/formoterol reduced the rate of exacerbations and reliever medication use compared with fixed dosing with salmeterol/fluticasone propionate. Budesonide/formoterol was well tolerated in both fixed and adjustable dosing regimens. In conclusion, in patients with persistent asthma symptoms despite treatment with inhaled corticosteroids, budesonide/formoterol administered via a single dry powder Turbuhaler device is an effective, well tolerated, convenient treatment option, which may have the potential for improved compliance. It appears to be as effective as treatment with budesonide and formoterol administered via separate inhalers and is more effective than budesonide monotherapy in improving PEF, controlling symptoms and preventing mild exacerbations. Adjustable maintenance dosing with budesonide/formoterol is associated with a lower overall dosage and appears to maintain control as effectively as fixed dosing.

Risk-benefit value of inhaled glucocorticoids: a pharmacokinetic/pharmacodynamic perspective

Inhaled glucocorticoids induce therapeutic and adverse systemic effects via the same types of receptors. Analysis of the pharmacokinetic/pharmacodynamic parameters of inhaled glucocorticoids generates a risk-benefit value (RBV). Targeted efficacy with minimal adverse effects helps to quantify an appropriate RBV. High lung deposition/targeting, high receptor binding, longer pulmonary retention, and high lipid conjugation are among the pharmacokinetic parameters to be considered for improved efficacy of the compound. Low or negligible oral bioavailability, small particle size and inactive drug at the oropharynx, high plasma protein binding, rapid metabolism, high clearance, and lower systemic concentrations are associated with low risks for adverse effects. Inhaled glucocorticoid potency is enhanced by solution inhalers, which result in higher pulmonary deposition and minimize local adverse effects. These properties, among others, determine the efficacy and safety of inhaled glucocorticoids. Currently available inhaled glucocorticoids do not provide the complete pharmacokinetic/pharmacodynamic parameters to optimize RBV, leaving room for improvement in the development of future agents.

Regulation of CYP3A5 by glucocorticoids and cigarette smoke in human lung-derived cells

CYP3A5 is the major CYP3A form in the human lung, and it is inducible by dexamethasone in the human A549 lung adenocarcinoma cell line. In the present study, we characterized the nature and mechanism of this induction process. The induction of CYP3A5 mRNA was assessed by quantitative reverse transcriptase-polymerase chain reaction in A549 cells. About 4-fold induction was detected by nanomolar concentrations of dexamethasone and also by budenoside and beclomethasone dipropionate, glucocorticoids used for the inhalation treatment of bronchial asthma, whereas the CYP3A4 inducers mifepristone (RU486), rifampicin, clotrimazole, and nifedipine were without effect. The glucocorticoid induction was blocked by the glucocorticoid receptor (GR) antagonist RU486. In transient transfection assays to A549 cells, CYP3A5 5' regulatory region was activated by the dexamethasone treatment. In contrast, dexamethasone was unable to induce CYP3A5 transcription in GR-deficient COS-1 cells, but the induction could be achieved after GR cotransfection. The CYP3A5 expression was measured in alveolar macrophages from patients with respiratory diseases. The CYP3A5 expression level was decreased by smoking, but glucocorticoid therapy had no statistically significant effect. In conclusion, CYP3A5 is induced in the A549 cells by glucocorticoids through a GR-mediated pathway, whereas smoking may be able to depress CYP3A5 expression.

Modulite technology: pharmacodynamic and pharmacokinetic implications

In the drive to replace chlorofluorinated hydrocarbons (CFCs) by alternative more environmentally friendly propellants in pressurized metered dose inhalers (pMDIs), Chiesi has developed new inhalers using Modulite technology. The aim was to obtain CFC-free pMDIs which are equivalent, in terms of safety and efficacy, to the previous CFC devices at the same dose. When beclometasone dipropionate (BDP) and budesonide Modulite formulations were compared to the equivalent CFC products there was no significant difference in morning serum cortisol or urinary cortisol excretion, at the maximum recommended daily dose (2000 micrograms or 1600 micrograms respectively). Single dose pharmacokinetic studies in both healthy volunteers and asthmatic patients compared systemic exposure (B17MP levels) for BDP-CFC with BDP Modulite and extrafine BDP-HFA (QVAR). B17MP levels for BDP-CFC and BDP Modulite were comparable, but substantially less than that seen with extrafine BDP-HFA. After 6 weeks of treatment in asthmatic patients, B17MP AUC after inhalation of BDP (1000 micrograms twice-daily) from BDP Modulite was comparable with that obtained after BDP-CFC (Becloforte). Plasma profile of BDP and B17MP were similar after inhalation from BDP Modulite with standard actuator or delivered via a spacer, suggesting that pulmonary delivery of BDP to the lung is similar with both actuators.

Mucoadhesive beclomethasone microspheres for powder inhalation: their pharmacokinetics and pharmacodynamics evaluation

The feasibility of prolonging drug action and/or reducing drug dosage using mucoadhesive beclomethasone dipropionate (BDP) microspheres for powder inhalation was investigated. BDP was spray-dried from ethanol solution or aqueous suspension systems dissolving a mucoadhesive polymer, hydroxypropylcellulose (HPC); this resulted in amorphous and crystalline BDP incorporation in the HPC microspheres (aBDP/HPC and cBDP/HPC; BDP-HPC ratio=1:4), respectively. These microspheres were administered as powder aerosols to healthy or antigen-induced, asthmatic guinea pigs, and BDP's retention in the lung (pharmacokinetics) and inhibitory duration with respect to eosinophil infiltration into the airways (pharmacodynamics) were compared to those for pure crystalline BDP (cBDP; 'control'). Both BDP/HPC microspheres were prepared within a respirable-size range of 2.5-2.9 microm. BDP's aqueous solubility was increased 25 times for aBDP/HPC, compared to crystalline counterpart. Pharmacokinetic profiles for three powders were dissolution-modulated. aBDP/HPC showed rapid BDP absorption from the lung (> or = 95% absorption for 180 min) with a greater metabolite (B17MP) formation, compared to cBDP, primarily due to the increased dissolution of amorphous BDP. In contrast, 86.0% of BDP remained at 180 min following cBDP/HPC administration, demonstrating the prolonged BDP's retention in the lung by virtue of poor dissolution (and/or release) and retarded mucociliary clearance. As a result, while cBDP (1.37 mg/kg) significantly inhibited eosinophil infiltration into the lungs of antigen-sensitized and -challenged guinea pigs for only 1-6 h, cBDP/HPC, despite a much lower drug dosage (0.25 mg/kg), was capable of maintaining such inhibitory effects for 24 h following administration. It appeared therefore that the prolonged lung retention of BDP by the use of the HPC microspheres (cBDP/HPC) was attributed to prolonging its pharmacological duration without requiring increased drug dosage.

Inhaled beclomethasone versus budesonide for chronic asthma

BACKGROUND

Beclomethasone dipropionate (BDP) and budesonide (BUD) are used widely in the treatment of chronic asthma. The two drugs have different in vitro pharmacokinetic characteristics. It is unclear whether this translates into clinically significant differences in efficacy or safety when treating children and adults with chronic asthma.

OBJECTIVES

To assess clinical outcomes in studies which have compared inhaled BDP and BUD in the treatment of chronic asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trial Register (1999) and reference lists of articles. We contacted trialists and pharmaceutical companies for additional studies and searched abstracts of major respiratory society meetings (1997-1999).

SELECTION CRITERIA

Prospective, randomised trials comparing BDP to BUD in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data; authors were contacted to clarify missing information. Quantitative analyses where undertaken using Review Manager 4.0.3 with Metaview 3.1.

MAIN RESULTS

24 studies met the criteria for inclusion (1174 subjects). Methodological quality was variable. A meta-analysis of crossover studies did not demonstrate a significant difference between BDP and BUD for FEV1, morning PEF, evening PEF, asthma symptoms or rescue beta2 agonist use, over a dose range of 400 to 1000 mcg/d. The majority of crossover trials had significant design flaws related to a lack of washout and/or failure to exclude carryover effects so the results must be viewed with caution. A single crossover study with adequate washout showed that BUD 400 mcg/d delivered via Turbohaler dry powder inhaler (DPI) may be more effective than BDP 400 mcg/d delivered via Rotahaler DPI in reducing histamine bronchial hyper-responsiveness: Weighted Mean Difference (WMD) 0.43 log10 PC20 FEV1 (95% Confidence Intervals (CI) 0.05, 0.81 log10 PC20 FEV1). A meta-analysis of two parallel group, dose down-titration studies (231 patients) showed that less BUD delivered via a Turbohaler DPI was required to maintain control in adults asthmatics compared to BDP delivered via metered dose inhaler with or without a spacer: WMD 444 mcg/d (95% CI 332, 556 mcg/d).

REVIEWER'S CONCLUSIONS

There is limited high quality randomised controlled trial data comparing the relative efficacy of BDP and BUD. Current guidelines (BTS 1997, GINA 1995, NHLBI 1997) assume BDP and BUD to have equal efficacy, such that for each defined level of asthma severity, the recommended doses BDP and BUD are the same. Although there is some data to suggest that BUD via Turbohaler is more effective than BDP via either Rotahaler or MDI (with and without spacer), these comparisons are confounded by use of different delivery devices, and are not sufficient to warrant a change in guideline recommendations.

Different glucocorticoids vary in their genomic and non-genomic mechanism of action in A549 cells

We have examined the effects of 12 glucocorticoids as inhibitors of A549 cell growth. Other than cortisone and prednisone, all the glucocorticoids inhibited cell growth and this was strongly correlated (r=0.91) with inhibition of prostaglandin (PG)E(2) formation. The molecular mechanism by which the active steroids prevented PGE(2) synthesis was examined and three groups were identified. Group A drugs did not inhibit arachidonic acid release but inhibited the induction of COX2. Group B drugs were not able to inhibit the induction of COX2 but inhibited arachidonic acid release through suppression of cPLA(2) activation. Group C drugs were apparently able to bring about both effects. The inhibitory actions of all steroids was dependent upon glucocorticoid receptor occupation since RU486 reversed their effects. However, group A acted through the NF-kappaB pathway to inhibit COX2 as the response was blocked by the inhibitor geldanamycin which prevents dissociation of GR and the effect was blocked by APDC, the NF-kappaB inhibitor. On the other hand, the group B drugs were not inhibited by NF-kappaB inhibitors or geldanamycin but their effect was abolished by the src inhibitor PP2. Group C drugs depended on both pathways. In terms of PGE(2) generation, there is clear evidence of two entirely separate mechanisms of glucocorticoid action, one of which correlates with NF-kappaB mediated genomic actions whilst the other, depends upon rapid effects on a cell signalling system which does not require dissociation of GR. The implications for these findings are discussed.

Enhanced pulmonary absorption following aerosol administration of mucoadhesive powder microspheres

Mucoadhesive, hydroxypropylcellulose (HPC) microspheres were prepared for powder inhalation and their feasibility for enhancing pulmonary drug absorption was investigated. Respirable-sized microspheres, incorporating crystalline or amorphous fluorescein (used as a model drug), were prepared by spray-drying aqueous or ethanol HPC systems, respectively. These were prepared from a variety of HPC grades (SL, L, M and H types) in different fluorescein-HPC ratios (1:1-1:10). The microspheres were administered to tracheally-intubated guinea pigs as powder aerosols and their fluorescein pharmacokinetics studied, and compared to those for pure crystalline fluorescein ('control'). All microspheres were prepared and aerosolized within a MMAD range of 1.3-2.6 microm (GSD< or =2.1). Fluorescein's dissolution was increased in the amorphous form by 6.5-fold when compared to the crystalline material (83.9-87.2 vs. 13.5 microg/ml, respectively). Poor dissolution for the 'control' crystalline fluorescein appeared to be rate-determined, which showed bi-phasic absorption profiles (T(max)=60 min), simultaneously competing with mucociliary clearance out of the lower airways. While the crystalline/HPC microspheres prolonged absorption, the amorphous fluorescein/HPC microspheres showed rapid absorption with T(max)=0 min (immediately after the administration had terminated). This was explained by enhanced fluorescein dissolution and was consistently observed irrespective of the fluorescein-HPC ratio or HPC grade. However, the microspheres with the least viscous HPC-SL and the lowest fluorescein-HPC ratio (1:1) failed to enhance bioavailability, presumably because the mucociliary clearance was undisturbed. In contrast, the microspheres with the highly viscous HPC-H with ratios > or = 1:4 successfully enhanced absorption, achieving 88.0% bioavailability by virtue of HPC increasing the dissolution and retarding the mucociliary clearance.

Inhaled budesonide/formoterol combination

Current evidence suggests that the addition of the long acting inhaled beta2-agonist formoterol to low or moderate doses of the inhaled corticosteroid budesonide is effective in improving lung function and reducing the incidence of asthma exacerbations. Concurrent use of budesonide with formoterol does not result in any untoward interaction that affects the pharmacodynamic or pharmacokinetic profiles of the individual drugs, or their adverse effect profiles. The administration of combined budesonide/formoterol is effective in improving morning and evening peak expiratory flow rates in adults with persistent asthma. Control of asthma symptoms is also significantly improved. In children aged 4 to 17 years, combined budesonide/formoterol is effective in increasing both morning and evening peak expiratory flow rates and significantly improving forced expiratory volume in 1 second (FEV1). The most commonly encountered adverse effects in clinical trials with combination budesonide/formoterol therapy have been respiratory infection, pharyngitis and coughing. No adverse effects on pulse rate, blood pressure or serum potassium have been reported with combination therapy.