Pharmacokinetics of fluticasone propionate inhaled via the Diskhaler and Diskus powder devices in patients with mild-to-moderate asthma

Pharmacokinetic properties and bioequivalence of orally inhaled salbutamol in healthy Chinese volunteers

CONTEXT

Salbutamol is a short-acting β2-adrenergic receptor agonist that has been used for many years for relief of bronchospasm. However, studies on the pharmacokinetic profile of orally inhaled salbutamol doses used in clinical practice have not yet been reported in Chinese subjects.

OBJECTIVE

The aim of this study was to compare the pharmacokinetics and evaluate the bioequivalence of two orally inhaled salbutamol formulations.

MATERIALS AND METHODS

A single-dose randomized fasting two-period, two-treatment and two-sequence crossover open-label bioequivalence study was conducted in 24 healthy Chinese adult male volunteers, with a 1-week washout period between treatments. Plasma concentrations of salbutamol were determined using liquid chromatography coupled to tandem mass spectrometry. Pharmacokinetic parameters, including AUC0-0.33 h, AUC0-24 h and Cmax were calculated and the 90% confidence intervals of the ratio (test/reference) pharmacokinetic parameters were obtained by analysis of variance on logarithmically transformed data.

RESULTS

The mean (SD) pharmacokinetic parameters of the reference drug were AUC0-0.33 h, 227.2 (89.9) pg·h/ml; AUC0-24 h, 2551.9 (1008.0) pg·h/ml; Cmax, 801.3 (307.3) pg/ml and t1/2, 5.14(1.36) h. Those of the test drug were AUC0-0.33 h, 244.0 (104.4) pg·h/ml; AUC0-24 h, 2664.4 (1081.8) pg·h/ml; Cmax, 873.7 (374.4) pg/ml, t1/2, 5.29 (1.23) h. The median value for Tmax was 0.25 h for both formulations. The 90% confidence intervals for the AUC0-0.33 h, AUC0-24 h and Cmax were in the range of 0.892-1.208, 0.876-1.195 and 0.911-1.203, respectively.

CONCLUSION

This single-dose study found that the test and reference products met the regulatory criteria for bioequivalence of China in healthy Chinese volunteers.

New developments in inhaler devices within pharmaceutical companies: A systematic review of the impact on clinical outcomes and patient preferences

BACKGROUND

Pharmaceutical companies offer an increasing number of inhaler devices, whether or not together with new substances, for maintenance treatment of patients with COPD or asthma. However, well-designed studies to support these developments are scarce.

OBJECTIVES

The aim of this research was to evaluate how far new developments of inhaler devices are scientifically supported and translate into improvements of patient preferences and/or clinical outcomes.

METHODS

A systematic literature review was performed to retrieve randomised controlled trials in patients with COPD or asthma that studied the in-company evolution of inhaler devices. Results were tabulated and discussed.

RESULTS

A total of 30 studies were found comparing Respimat(®) vs. HandiHaler(®), Diskus(®)(Accuhaler(®)) vs. Diskhaler(®)(Rotadisk(®)) or pMDI, Ellipta(®) vs. Diskus(®)(Accuhaler(®)), Nexthaler(®) vs. pMDI, or Breezhaler(®) vs. Aerolizer(®). These studies show that developments of inhaler devices may improve patient satisfaction but do not lead to demonstrable improvements in clinical efficacy. Current changes of devices are most commonly parallelled by changes in administration frequency towards once daily treatment. The only well-documented effect was found for the Respimat(®) Soft Mist™ Inhaler, which realises a more than 3-fold lowering of the once-daily tiotropium dose through increased performance of the inhaler device. There are however, no data on clinical efficacy or safety comparing the two devices at the same dosage.

CONCLUSIONS

Future developments of inhaler devices should all require well-designed studies to demonstrate patient benefit.

Aerosol particle size does not predict pharmacokinetic determined lung dose in children

In vitro measures of aerosol particles size, such as the fine particle mass, play a pivotal role for approval of inhaled anti-asthmatic drugs. However, the validity as a measure of dose to the lungs in children lacks evidence. In this study we investigated for the first time the association between an in vivo estimate of lung dose of inhaled drug in children and the corresponding particle size segments assessed ex vivo. Lung dose of fluticasone propionate after inhalation from a dry powder inhaler (Diskus®) was studied in 23 children aged 4-7 and 12-15 years with mild asthma. Six-hour pharmacokinetics was assessed after single inhalation. The corresponding emitted mass of drug in segments of aerosol particle size was assessed ex vivo by replicating the inhalation flows recorded by transducers built into the Diskus® inhaler and re-playing them in a breathing simulator. There was no correlation between any inhaled particle size segment and lung dose assessed by pharmacokinetics and adjusted for age and body size. Measures of particles size segments were not related to lung dose in children. Until further evidence is provided it may be warranted to emphasize pharmacokinetic or pharmacodynamic assessments of drug delivery to the lung.

Fluticasone versus placebo for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a relatively new inhaled corticosteroid for the treatment of asthma.

OBJECTIVES

To assess efficacy and safety outcomes in studies that compared FP to placebo for treatment of chronic asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (January 2008), reference lists of articles, contacted trialists and searched abstracts of major respiratory society meetings (1997-2006).

SELECTION CRITERIA

Randomised trials in children and adults comparing FP to placebo in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and risk of bias.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data. Quantitative analyses were undertaken using Review Manager software.

MAIN RESULTS

Eighty-six studies met the inclusion criteria, recruiting 16,160 participants. In non-oral steroid treated asthmatics with mild and moderate disease FP resulted in improvements from baseline compared with placebo across all dose ranges (100 to 1000 mcg/d) in FEV1 (between 0.1 to 0.43 litres); morning PEF (between 23 and 46 L/min); symptom scores (based on a standardised scale, between 0.44 and 0.7); reduction in rescue beta-2 agonist use (between 1 and 1.4 puffs/day). High dose FP increased the number of patients who could withdraw from prednisolone: FP 1000-1500 mcg/day Peto Odds Ratio 14.07 (95% CI 7.17 to 27.57). FP at all doses led to a greater likelihood of sore throat, hoarseness and oral Candidiasis.

AUTHORS' CONCLUSIONS

Doses of FP in the range 100-1000 mcg/day are effective. In most patients with mild-moderate asthma improvements with low dose FP are only a little less than those associated with high doses when compared with placebo. High dose FP appears to have worthwhile oral-corticosteroid reducing properties. FP use is accompanied by an increased likelihood of oropharyngeal side effects.

Fluticasone at different doses for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a high-potency inhaled corticosteroid used in the treatment of asthma.

OBJECTIVES

1. To assess the efficacy and safety outcomes of inhaled fluticasone at different nominal daily doses in the treatment of chronic asthma.2. To test for the presence of a dose-response effect.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register (January 2008).

SELECTION CRITERIA

Randomised trials in children and adults comparing fluticasone at different nominal daily doses in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

One review author extracted data. These were checked and verified by a second reviewer. Quantitative analyses where undertaken using Review Manager.

MAIN RESULTS

Fifty-one published and unpublished trials (representing 55 group comparisons, 10,797 participants) met the inclusion criteria. In asthmatics with mild to moderate disease who were not on oral steroids, FP did not exhibit a dose-response effect in the lower dose comparisons in FEV1 (50mcg, 100mcg, 200mcg and 4-500mcg daily). There were no statisitically significant differences between 4-500mcg and 800-1000mcg, and between 50-100 and 800-1000mcg of FP. When 200mcg was compared with 800-1000mcg daily FEV1 favoured the four/five fold increase. For PEF, a dose response was present with FP when low and moderate, and low and high doses of FP were compared. There was no evidence of a dose-response effect on symptoms or rescue beta-2 agonist use. The likelihood of hoarseness and oral candidiasis was significantly greater for the higher doses (800 to 1000 microg/day). People with oral steroid-dependent asthma treated with FP (2000 microg/day) were significantly more likely to reduce oral prednisolone than those on 1000 to 1500 microg/day (Peto odds Ratio 2.8, 95% CI 1.3 to 6.3). The highest dose also allowed a significant reduction in daily oral prednisolone dose compared to 1000 to 1500 microg/day (WMD 2.0 mg/day, 95% CI 0.1 to 4.0 mg/day).

AUTHORS' CONCLUSIONS

We have not found evidence of a pronounced dose response in FEV1 with increasing doses of fluticasone. The number of studies contributing to our primary outcomes was low. At dose ratios of 1:2, there are statistically significant differences in favour of the higher dose in morning peak flow across the low dose range. The clinical impact of these differences is open to interpretation. Patients with moderate disease achieve similar levels of asthma control on medium doses of fluticasone (400 to 500 microg/day) as they do on high doses (800 to 1000 microg/day). More work in severe asthma would help to confirm that doses of FP above 500 microg/day confer greater benefit in this subgroup than doses of around 200 microg/day. In oral corticosteroid-dependent asthmatics, reductions in prednisolone requirement may be gained with FP 2000 microg/day.

Minimizing matrix effects in the development of a method for the determination of salmeterol in human plasma by LC/MS/MS at low pg/mL concentration levels

Salmeterol is an inhaled bronchodilator drug used for treatment of asthma. Its concentrations in plasma are very low or undetectable by previously developed methods. The present paper describes a method for analysis of salmeterol in human plasma with 2.5 pg/mL lower limit of quantitation. Despite the basic character of the drug the method uses mixed mode anion-exchange solid phase extraction for sample preparation combined with a column switching approach to minimize matrix effects. Samples are separated and detected by LC/MS/MS. The method is easy to use, only requires 0.5 mL of plasma and was validated for use in bioanalytical applications. The method does not suffer from interference from co-administered fluticasone propionate.

Fluticasone versus placebo for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a relatively new inhaled corticosteroid for the treatment of asthma.

OBJECTIVES

1. To assess efficacy and safety outcomes in studies that compared FP to placebo for treatment of chronic asthma.2. To explore the presence of a dose-response effect.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (January 2005), reference lists of articles, contacted trialists and searched abstracts of major respiratory society meetings (1997-2004).

SELECTION CRITERIA

Randomised trials in children and adults comparing FP to placebo in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data. Quantitative analyses were undertaken using RevMan 4.2

MAIN RESULTS

Seventy-five studies met the inclusion criteria (14,208 participants). Methodological quality was high. In non-oral steroid treated asthmatics with mild and moderate disease FP resulted in improvements from baseline compared with placebo across all dose ranges (100 to 1000 mcg/d) in FEV1 (between 0.13 to 0.45 litres); morning PEF (between 23 and 47 L/min); symptom scores (based on a standardised scale, between 0.5 and 0.85); reduction in rescue beta-2 agonist use (between 1.2 and 2.2 puffs/day). High dose FP increased the number of patients who could withdraw from prednisolone: FP 1000-1500 mcg/day Peto Odds Ratio 14.07 (95% CI 7.17 to 27.57). FP at all doses led to a greater likelihood of sore throat, hoarseness and oral Candidiasis. Twenty-one patients would need to be treated for one extra to develop Candidiasis (FP 500 mcg/day), whilst only three or four patients need to be treated to avoid one extra patient being withdrawn due to lack of efficacy at all doses of FP.

AUTHORS' CONCLUSIONS

Doses of FP in the range 100-1000 mcg/day are effective. In most patients with mild-moderate asthma improvements with low dose FP are only a little less than those associated with high doses when compared with placebo. High dose FP appears to have worthwhile oral-corticosteroid reducing properties. FP use is accompanied by an increased likelihood of oropharyngeal side effects.

Inhaled fluticasone at different doses for chronic asthma in adults and children

BACKGROUND

Inhaled fluticasone propionate (FP) is a high-potency inhaled corticosteroid used in the treatment of asthma.

OBJECTIVES

1. To assess the efficacy and safety outcomes of inhaled fluticasone at different nominal daily doses in the treatment of chronic asthma. 2. To test for the presence of a dose-response effect.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register (January 2005) and reference lists of articles. We contacted trialists and pharmaceutical companies for additional studies and searched abstracts of major respiratory society meetings (1997 to 2004).

SELECTION CRITERIA

Randomised trials in children and adults comparing fluticasone at different nominal daily doses in the treatment of chronic asthma. Two reviewers independently assessed articles for inclusion and methodological quality.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data. These were checked and verified by a second reviewer. Quantitative analyses where undertaken using RevMan (Analyses 1.0.2).

MAIN RESULTS

Forty-three studies (45 data sets with 8913 participants) met the inclusion criteria. Methodological quality was high. In asthmatics with mild to moderate disease who were not on oral steroids a dose-response effect was present with FP for change in morning peak expiratory flow (PEF). For low doses (100 versus 200 microg/day) the weighted mean difference (WMD) was 6.29 litres/min, 95% confidence interval (CI) 2.28 to 10.29. Comparing medium (400 to 500 microg/day) to low dose (200 microg/day) FP the WMD was 6.46 litres/min (95% CI 3.02 to 9.89); this effect was more pronounced in one trial with more severely asthmatic children. For FP 100 versus 400 to 500 microg/day the WMD was 8 litres/min (95% CI 1 to 15) and at high versus low doses (800 to 1000 versus 50 to 100 microg/d) the WMD was 22 litres/min (95% CI 15 to 29). When high and medium doses were compared there was no significant difference in the change in morning PEF: at 400 to 500 versus 800 to 1000 microg/day the WMD was 0.16 litres/min (95% CI 6.95 to 6.63). There was no dose-response effect on symptoms or rescue beta-2 agonist use. The likelihood of hoarseness and oral candidiasis was significantly greater for the higher doses (800 to 1000 microg/day). People with oral steroid-dependent asthma treated with FP (2000 microg/day) were significantly more likely to reduce oral prednisolone than those on 1000 to 1500 microg/day (Peto odds Ratio 2.8, 95% CI 1.3 to 6.3). The highest dose also allowed a significant reduction in daily oral prednisolone dose compared to 1000 to 1500 microg/day (WMD 2.0 mg/day, 95% CI 0.1 to 4.0 mg/day).

AUTHORS' CONCLUSIONS

Effects of fluticasone are dose dependent but relatively small. At dose ratios of 1:2, there are significant differences in favour of the higher dose in morning peak flow across the low dose range. The clinical impact of these differences is open to interpretation. Patients with moderate disease achieve similar levels of asthma control on medium doses of fluticasone (400 to 500 microg/day) as they do on high doses (800 to 1000 microg/day). More work in severe asthma would help to confirm that doses of FP above 500 microg/day confer greater benefit in this subgroup than doses of around 200 microg/day. In oral corticosteroid-dependent asthmatics, reductions in prednisolone requirement may be gained with FP 2000 microg/day.

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.

High dose versus low dose inhaled corticosteroid as initial starting dose for asthma in adults and children

BACKGROUND

Inhaled corticosteroids (ICS) form the basis of maintenance therapy in asthma and their efficacy is well established. However, the optimal starting dose of ICS is not clearly established. Recent reviews demonstrate a relatively flat efficacy curve for ICS and increasing side effects with increasing ICS doses. High doses are frequently prescribed and there are now reports of significant side effects occurring with high dose ICS use. These issues demonstrate the need to establish the optimal starting dose of ICS in asthma.

OBJECTIVES

To establish the optimal starting dose of ICS by evaluating the efficacy of initial high dose ICS with low dose ICS in subjects with asthma, not currently on ICS.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register and reference lists of articles. Date of last search: January 2003

SELECTION CRITERIA

Randomised controlled trials of two different doses of the same ICS in adults and children with asthma with no concomitant ICS or OCS.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted independently by two reviewers. Study authors were contacted for confirmation. Trials were analysed according to the following ICS dose comparisons: step down vs constant dose ICS (n=7); high vs moderate (n=11); high vs low (n=9); moderate vs low (n=11); fold change in dose (all studies).

MAIN RESULTS

31 papers reporting the results of 26 trials were included in the review. For studies that compared a step down approach to a constant moderate/low ICS dose, there were no significant differences in lung function, symptoms, rescue medications or asthma control between the two treatment approaches. Significant but clinically small improvements in percent predicted FEV(1) ( WMD 5.32, 95% CI 0.65 to 9.99) and non significant improvements in the change in morning PEF were found for high dose ICS compared to moderate dose ICS. There were no significant differences in efficacy between high and low dose ICS. For moderate dose ICS, compared to low dose ICS, there were significant improvements in the change in morning PEF l/min from baseline (WMD 11.14, 95% CI 1.34 to 20.93) and nocturnal symptoms (SMD -0.29, 95% CI -0.53 to -0.06 ). Commencing ICS at double or quadruple a base moderate or low dose had no greater effect than commencing with the base dose. Several studies reported greater improvement in airway hyperresponsiveness for high dose ICS.

REVIEWERS' CONCLUSIONS

For patients with asthma who require ICS, commencing with a moderate dose ICS is equivalent to commencing with a high dose ICS and down-titrating. The small significant benefits of commencing with a high ICS dose are not of sufficient clinical benefit to warrant its use when compared to moderate or low dose ICS. Initial moderate ICS dose appears to be more effective than initial low ICS dose. High dose ICS may be more effective than moderate or low dose ICS for airway hyperresponsiveness. There is no benefit in doubling or quadrupling ICS in subjects with stable asthma.

Lung deposition and systemic availability of fluticasone Diskus and budesonide Turbuhaler in children

Pharmacokinetic studies can be used to measure lung dose of inhaled drugs. The aim of this study was to compare the lung deposition of budesonide (BUD) inhaled from Turbuhaler (AstraZeneca, Lund, Sweden) and fluticasone propionate (FP) inhaled from Diskus (GlaxoSmithKline, London, UK) and to assess if the study design used for pharmacokinetic studies can be simplified. Plasma levels of BUD and FP were measured for 21 hours on five separate days in 15 patients aged 8 to 14 years: (1) Intravenous infusion of 200 microg BUD, (2) intravenous infusion of 200 microg fluticasone dipropionate, (3) inhalation of 800 microg BUD via Turbuhaler, (4) inhalation of 750 microg FP via Diskus, and (5) inhalation of BUD and FP on the same day. Charcoal was ingested to eliminate drug uptake from the gastrointestinal tract. The mean lung deposition of drug after Turbuhaler and Diskus inhalation was 30.8 and 8.0% when BUD and fluticasone were administered on separate days and 29.5% (BUD) and 7.6% (fluticasone) when the two drugs were inhaled on the same day. Lung deposition is four times higher in children after inhalation from Turbuhaler than after inhalation from Diskus. Pharmacokinetic studies with BUD and FP can be simplified because the two treatments can be administered on the same day.

The influence of inhaler selection on efficacy of asthma therapies

Many different devices are available to aid inhalational drug delivery. Although each device is claimed to have advantages over its rivals, the evidence to support greater efficacy of a particular device is scanty. Most comparative studies are underpowered or flawed in their design. They may use inappropriate end-points, or involve healthy subjects, whose response may be very different from the patient with acute severe asthma. The dosage of drug used in a trial may be at the shallow part of the dose-response curve, masking differences in devices. Only in a few cases have clinical trials detected a significant difference between devices, and trials have rarely taken patient preference into account. The most efficacious device in practice is likely to be the one that the patient will use regularly and in accordance with a health care workers' recommendations.

Fluticasone propionate and mometasone furoate have equivalent transcriptional potencies

BACKGROUND

Glucocorticoids exert their anti-inflammatory effects mainly through transrepression of the transcription factors activator protein-1 (AP-1) and nuclear factor-kappa B (NF-kappaB). Certain adverse effects of glucocorticoids are mediated through gene transactivation. Fluticasone propionate (FP) and mometasone furoate (MF) are the most recently developed topical glucocorticoids for the treatment of airway disorders. Their relative capacities to repress AP-1 and NF-kappaB activities are not known and comparison of their transactivation potencies has given unclear results.

OBJECTIVE

To determine the relative transactivation and transrepression potencies of FP and MF.

METHODS

Transactivation assays were performed in HeLa cells carrying a glucocorticoid-inducible luciferase gene. To measure transrepressive potencies of FP and MF, A549 lung epithelial cells were transiently transfected with an AP-1- or NF-kappaB-dependent luciferase gene. Using an immunoassay, we also evaluated the ability of MF and FP to inhibit the production of Regulated upon Activation, Normal T-cell Expressed and Secreted (RANTES), a pro-inflammatory cytokine, whose gene is controlled by AP-1 and NF-kappaB. Areas under the dose-response curve were calculated to determine relative potencies.

RESULTS

FP and MF are equipotent for transactivation. Both molecules show globally the same potency to inhibit AP-1 and NF-kappaB activities and RANTES production. MF and FP have very significant transcriptional effects at 2x10(-10) M, which is the peak concentration reached in the plasma after inhalation of high dosages. Indeed, they produce a 17-fold induction of luciferase in the transactivation assay, and inhibit AP-1 activity, NF-kappaB activity and RANTES release by approximately 40%.

CONCLUSION

FP and MF have the same ability to trigger gene activation and also the same potency to inhibit AP-1 and NF-kappaB activities. Their strong transcriptional effects at 2x10(-10) M suggest that these compounds act not only topically but also systemically, with the risk of provoking concomitant adverse effects at high dosages.

Single-dose and steady-state pharmacokinetic and pharmacodynamic evaluation of therapeutically clinically equivalent doses of inhaled fluticasone propionate and budesonide, given as Diskus or Turbohaler dry-powder inhalers to healthy subjects

Direct comparisons of the pharmacokinetic (PK) and systemic pharmacodynamic (PD) properties of inhaled corticosteroids after single and multiple dosing in the same subjects are scarce. The objective of this study was to compare thePK/PDproperties of clinically equivalent, single, and multiple doses of dry-powder formulations of inhaled fluticasone propionate (FP 200 and 500 microg via Diskus) and budesonide (BUD, 400 and 1,000 microg via Turbohaler). Fourteen healthy subjects completed a double-blind, double-dummy, randomized, placebo-controlled, five-way crossover study consisting of a single dose administered at 8 a.m. on day 1 followed by 4 days of twice-daily dosing at 8 a.m. and 8 p.m. on days 2 to 5. Serum concentrations of FP and BUD were measured using validated liquid chromatography/ mass spectrometry assays. The 24-hour cumulative cortisol suppression (CCS) in serum was monitored as the pharmacodynamic surrogate marker. Peak serum concentrations following single and multiple dosing were observed 10 to 30 minutes after inhalation for BUD and 30 to 90 minutes afterinhalation of FP with no influence of dose ordosingregimen. After a single dose of 1000 microg BUD and 500 microg FP the median estimates of terminal half-life and mean residence time were 3.5 and 3.9 hours for BUD and 10.1 and 12.0 hours for FP, respectively. Using previously reported intravenous data, the mean absorption times (MAT) were calculated to be around 2 hours and 7 hours for BUD and FP respectively. On average, the area under the curve (A UC) at steady state (day 5) was up to 30% higher for BUD compared to that over a 12-hour period following the first dose on day 1, whereas A UC estimates were 50% to 80% higherforFP at steady state, indicating accumulation. However, the steady-state Cmax values were seven to eight times and AUC values three to four times higher for BUD than for FP. Comparison of active treatment data with placebo showed that CCS after a single dose was not pronounced for any of the doses/drugs studied. On day 5, both doses of BUD caused statistically significant suppression (CCS of 19% for the 400 microg dose and 36% for the 1,000 microg dose). For FP only the high dose had a statistically significant effect on serum cortisol (CCS of 14% for the 200 microg dose and 27% for the 500 microg dose). Compared to BUD, FP has slower pulmonary absorption and slower elimination kinetics. However, following inhalation of therapeutically equipotent, multiple twice-daily doses in healthy subjects, the systemic effects of FP delivered via Diskus on AUC24 serum cortisol were relatively low and similar to those of BUD delivered via Turbohaler.

Comparison of the systemic availability of fluticasone propionate in healthy volunteers and patients with asthma

OBJECTIVES

The aim of this analysis was to compare the systemic exposure to inhaled fluticasone propionate (FP) after administration of either single or repeated dose regimens via dry powder and metered-dose inhalers in patients with asthma and healthy volunteers.

BACKGROUND

The pharmacokinetics of FP, a topically active glucocorticoid administered by inhalation for the treatment of asthma and rhinitis, are well characterised in healthy volunteers. As asthma is characterised by pathophysiological changes in the lung, it may be inappropriate to use data from studies in healthy volunteers to predict the deposition and absorption of FP in patients with asthma.

METHODS AND RESULTS

Pooled data from 13 pharmacokinetic studies showed that the systemic availability of FP (measured as area under the plasma FP concentration-time curve) after single or multiple administration by inhalation was 2 to 3 times lower in patients with asthma than in healthy volunteers. This observation correlated well with the systemic effects of FP in the 2 groups. Reduction in 24-hour urinary cortisol excretion after inhalation of FP (determined in 9 of the studies) was greater in healthy volunteers than in patients with asthma. The hypothalamic-pituitary-adrenal axis suppression caused by systemic exposure to FP in adults with asthma is therefore substantially less than that in healthy volunteers.

CONCLUSION

Differences in the deposition of FP in the lungs of patients with asthma, probably caused by obstructed inspiratory airflow, may explain this observation.