Bioavailability of orally administered micronised fluticasone propionate

Spray-Dried Nanolipid Powders for Pulmonary Drug Delivery: A Comprehensive Mini Review

Lung diseases have received great attention in the past years because they contribute approximately one-third of the total global mortality. Pulmonary drug delivery is regarded as one of the most appealing routes to treat lung diseases. It addresses numerous drawbacks linked to traditional dosage forms. It presents notable features, such as, for example, a non-invasive route, localized lung drug delivery, low enzymatic activity, low drug degradation, higher patient compliance, and avoiding first-pass metabolism. Therefore, the pulmonary route is commonly explored for delivering drugs both locally and systemically. Inhalable nanocarrier powders, especially, lipid nanoparticle formulations, including solid-lipid and nanostructured-lipid nanocarriers, are attracting considerable interest in addressing respiratory diseases thanks to their significant advantages, including deep lung deposition, biocompatibility, biodegradability, mucoadhesion, and controlled drug released. Spray drying is a scalable, fast, and commercially viable technique to produce nanolipid powders. This review highlights the ideal criteria for inhalable spray-dried SLN and NLC powders for the pulmonary administration route. Additionally, the most promising inhalation devices, known as dry powder inhalers (DPIs) for the pulmonary delivery of nanolipid powder-based medications, and pulmonary applications of SLN and NLC powders for treating chronic lung conditions, are considered.

Pharmacokinetic Models for Inhaled Fluticasone Propionate and Salmeterol Xinafoate to Quantify Batch-to-Batch Variability

Advair Diskus is an essential treatment for asthma and chronic obstructive pulmonary disease. It is a dry powder inhaler with a combination of fluticasone propionate (FP) and salmeterol xinafoate (SX). However, the pharmacokinetics (PK) batch-to-batch variability of the reference-listed drug (RLD) hindered its generic product development. This work developed the PK models for inhaled FP and SX that could represent potential batch variability. Two batches each of the reference and the test product (R1, R2, T1, T2) of Advair Diskus (100 μg FP/50 μg SX inhalation) were administered to 60 healthy subjects in a 4-period, 4-sequence crossover study. The failure of the bioequivalence (BE) between R1 and R2 confirmed the high between-batch variability of the RLD. Non-linear mixed effect modeling was used to estimate the population mean PK parameters for each batch. For FP, a 2-compartment model with a sequential dual zero-order absorption best described the PK profile. For SX, a 2-compartment model with a first-order absorption model best fit the data. Both models were able to capture the plasma concentration, the maximum concentration, and the total exposure (AUCinf) adequately for each batch, which could be used to simulate the BE study in the future. In vitro properties were also measured for each batch, and the batch with a higher fraction of the fine particle (diameter < 1 µm, < 2 µm) had a higher AUCinf. This positive correlation for both FP and SX could potentially assist the batch selection for the PK BE study.

The Pharmacokinetics of Inhaled Drugs

The pharmacokinetic (PK) profile of a drug after inhalation may differ quite markedly from that seen after dosing by other routes of administration. Drugs may be administered to the lung to elicit a local action or as a portal for systemic delivery of the drug to its site of action elsewhere in the body. Some knowledge of PK is important for both locally- and systemically-acting drugs. For a systemically-acting drug, the plasma concentration-time profile shares some similarities with drug given by the oral or intravenous routes, since the plasma concentrations (after the distribution phase) will be in equilibrium with concentrations at the site of action. For a locally-acting drug, however, the plasma concentrations reflect its fate after it has been absorbed and removed from the airways, and not what is available to its site of action in the lung. Consequently, those typical PK parameters which are determined from plasma concentration measurements, e.g., area under the curve (AUC), Cmax, tmax and post-peak t1/2 may provide information on the deposition and absorption of drugs from the lung; however, the information from these parameters becomes more complicated to decipher for those drugs which are locally-acting in the lung. Additionally, the plasma concentration profile for both locally- and systemically-acting drugs will not only reflect drug absorbed from the lung but also that absorbed from the gastrointestinal (GI) tract from the portion of the dose which is swallowed. This absorption from the GI tract adds a further complication to the interpretation of plasma concentrations, particularly for locally-acting drugs. The influence of physiological and pathological factors needs to be considered in the absorption of some inhaled drugs. The absorption of some hydrophilic drugs is influenced by the inspiratory maneuver used during initial inhalation of the drug, and at later times after deposition. Similarly, the effects of smoking have been shown to increase lung permeability and increase the absorption of certain hydrophilic drugs. The effects of different disease states of the lung have less defined influences on absorption into the systemic circulation.

Managing moderate-to-severe paediatric asthma: a scoping review of the efficacy and safety of fluticasone propionate/salmeterol

BACKGROUND

Fluticasone propionate/salmeterol xinafoate (FP/SAL) is an inhaled corticosteroid (ICS) and long-acting β2-agonist (LABA) combination, indicated for the regular treatment of children (aged >4 years) with asthma that is inadequately controlled with ICS monotherapy plus as-needed short-acting β2-agonists, or already adequately controlled with ICS/LABA.

OBJECTIVE

Compared with the adult population, fewer clinical studies have investigated the efficacy of FP/SAL in paediatric patients with moderate and moderate-to-severe asthma. In this review, we synthesise the available evidence for the efficacy and safety of FP/SAL in the paediatric population, compared with other available therapies indicated for asthma in children.

ELIGIBILITY CRITERIA

A literature review identified randomised controlled trials and observational studies of FP/SAL in the paediatric population with moderate-to-severe asthma.

SOURCES OF EVIDENCE

The Medline database was searched using PubMed (https://pubmed.ncbi.nlm.nih.gov/), with no publication date restrictions. Search strategies were developed and refined by authors.

CHARTING METHODS

Selected articles were screened for clinical outcome data (exacerbation reduction, nocturnal awakenings, lung function, symptom control, rescue medication use and safety) and a table of key parameters developed.

RESULTS

Improvements in asthma outcomes with FP/SAL include reduced risk of asthma-related emergency department visits and hospitalisations, protection against exercise-induced asthma and improvements in measures of lung function. Compared with FP monotherapy, greater improvements in measures of lung function and asthma control are reported. In addition, reduced incidence of exacerbations, hospitalisations and rescue medication use is observed with FP/SAL compared with ICS and leukotriene receptor antagonist therapy. Furthermore, FP/SAL therapy can reduce exposure to both inhaled and oral corticosteroids.

CONCLUSIONS

FP/SAL is a reliable treatment option in patients not achieving control with ICS monotherapy or a different ICS/LABA combination. Evidence shows that FP/SAL is well tolerated and has a similar safety profile to FP monotherapy. Thus, FP/SAL provides an effective option for the management of moderate-to-severe asthma in the paediatric population.

Central and peripheral lung deposition of fluticasone propionate dry powder inhaler formulations in humans characterized by population pharmacokinetics

This study aimed to gain an in-depth understanding of the pulmonary fate of three experimental fluticasone propionate (FP) dry powder inhaler formulations which differed in mass median aerodynamic diameters (MMAD; A-4.5 µm, B-3.8 µm and C-3.7 µm; total single dose: 500 µg). Systemic disposition parameter estimates were obtained from published pharmacokinetic data after intravenous dosing to improve robustness. A biphasic pulmonary absorption model, with mucociliary clearance from the slower absorption compartment, and three systemic disposition compartments was most suitable. Rapid absorption, presumably from peripheral lung, had half-lives of 6.9 to 14.6 min. The peripherally deposited dose (12.6 µg) was significantly smaller for formulation A-4.5 µm than for the other formulations (38.7 and 39.3 µg for B-3.8 µm and C-3.7 µm). The slow absorption half-lives ranged from 6.86 to 9.13 h and were presumably associated with more central lung regions, where mucociliary clearance removed approximately half of the centrally deposited dose. Simulation-estimation studies showed that a biphasic absorption model could be reliably identified and that parameter estimates were unbiased and reasonably precise. Bioequivalence assessment of population pharmacokinetics derived central and peripheral lung doses suggested that formulation A-4.5 µm lacked bioequivalence compared to the other formulations both for central and peripheral doses. In contrast, the other fomulations were bioequivalent. Overall, population pharmacokinetics holds promise to provide important insights into the pulmonary fate of inhalation drugs, which are not available from non-compartmental analysis. This supports the assessment of the pulmonary bioequivalence of fluticasone propionate inhaled formulations through pharmacokinetic approaches, and may be helpful for discussions on evaluating alternatives to clinical endpoint studies.

Nebulized dexamethasone sodium phosphate in the treatment of horses with severe asthma

Background

A study reported low systemic availability of injectable dexamethasone nebulized to healthy horses using the Flexineb mask. When used in horses with severe asthma and a different nebulizer, lack of efficacy and cortisol suppression were observed.

Hypothesis

Nebulized dexamethasone is as effective as PO administration for the treatment of severe asthma in horses.

Animals

Twelve horses with severe asthma from a research herd.

Methods

Randomized clinical trial. Horses were divided into 2 groups and received 5 mg of dexamethasone sodium phosphate by nebulization using a Flexineb mask (NE, n = 6) or PO (OR, n = 6) q24h for 7 days. Lung function and serum cortisol concentrations were evaluated at baseline, after 4 days of treatment (D4) and 1 day after the last treatment (D8). Data were analyzed using linear mixed models with Benjamini‐Hochberg adjustments.

Results

Lung resistance significantly improved at D4 (mean decrease ± SD, −1.5 ± 0.45 cm H₂O/L/s; 95% confidence interval [CI], −2; −0.6) and D8 (−1.4 ± 0.45 cm H₂O/L/s; 95% CI, −2.4; −0.5) compared to baseline in the OR group only (P = .004 and .01, respectively). Serum cortisol concentration was significantly decreased at D4 and D8 for both groups (maximum decrease, −1.2 ± 0.3 μg/dL; 95% CI, −1.9; −0.6 at D4 for NE group and −2.2 ± 0.3 μg/dL; 95% CI, −2.8; −1.6 at D8 for OR group; P < .001).

Conclusions and Clinical Importance

Oral, but not nebulized dexamethasone is an effective therapy for horses with severe asthma and both treatment modalities inhibit the hypothalamic‐pituitary‐adrenal axis.

Inhaled RNA Therapeutics for Obstructive Airway Diseases: Recent Advances and Future Prospects

Obstructive airway diseases, e.g., chronic obstructive pulmonary disease (COPD) and asthma, represent leading causes of morbidity and mortality worldwide. However, the efficacy of currently available inhaled therapeutics is not sufficient for arresting disease progression and decreasing mortality, hence providing an urgent need for development of novel therapeutics. Local delivery to the airways via inhalation is promising for novel drugs, because it allows for delivery directly to the target site of action and minimizes systemic drug exposure. In addition, novel drug modalities like RNA therapeutics provide entirely new opportunities for highly specific treatment of airway diseases. Here, we review state of the art of conventional inhaled drugs used for the treatment of COPD and asthma with focus on quality attributes of inhaled medicines, and we outline the therapeutic potential and safety of novel drugs. Subsequently, we present recent advances in manufacturing of thermostable solid dosage forms for pulmonary administration, important quality attributes of inhalable dry powder formulations, and obstacles for the translation of inhalable solid dosage forms to the clinic. Delivery challenges for inhaled RNA therapeutics and delivery technologies used to overcome them are also discussed. Finally, we present future prospects of novel inhaled RNA-based therapeutics for treatment of obstructive airways diseases, and highlight major knowledge gaps, which require further investigation to advance RNA-based medicine towards the bedside.

Chitinases and Chitinase-Like Proteins in Obstructive Lung Diseases - Current Concepts and Potential Applications

Chitinases, enzymes that cleave chitin’s chain to low molecular weight chitooligomers, are widely distributed in nature. Mammalian chitinases belong to the 18-glycosyl-hydrolase family and can be divided into two groups: true chitinases with enzymatic activity (AMCase and chitotriosidase) and chitinase-like proteins (CLPs) molecules which can bind to chitin or chitooligosaccharides but lack enzymatic activity (eg, YKL-40). Chitinases are thought to be part of an innate immunity against chitin-containing parasites and fungal infections. Both groups of these hydrolases are lately evaluated also as chemical mediators or biomarkers involved in airway inflammation and fibrosis. The aim of this article is to present the current knowledge on the potential role of human chitinases and CLPs in the pathogenesis, diagnosis, and course of obstructive lung diseases. We also assessed the potential role of chitinase and CLPs inhibitors as therapeutic targets in chronic obstructive pulmonary disease and asthma.

Effect of Food Intake and Body Position on the Pharmacokinetics of Swallowed APT-1011, a Fluticasone Orally Disintegrating Tablet, in Healthy Adult Volunteers

Eosinophilic esophagitis is a common atopic disease of the esophagus. APT-1011 is an orally disintegrating tablet formulation of fluticasone propionate under development for the treatment of eosinophilic esophagitis. The objective of this study was to evaluate the pharmacokinetics, safety, and tolerability of APT-1011 under fed or fasted conditions in the morning (am) or at bedtime (hs) in the supine position. The study was a randomized, single-dose, 3-way, crossover design in healthy adult volunteers. In each study period participants received 2 3-mg orally disintegrating APT-1011 tablets. Serial plasma samples were collected before dosing and up to 72 hours after each dose. Twenty-two participants completed the study. The fluticasone propionate peak concentration (C_max ) ranged from 5.97 to 200 pg/mL. Compared with am-fasted dosing, am-fed dosing was associated with a modestly higher C_max (∼21%) but lower net exposure (area under the concentration-time curve ∼56% difference) and shorter time to reach C_max (T_max ) (T_max fasted = 10 hours, fed = 5 hours). Dosing at hs resulted in an 18% and 32% decrease in C_max relative to am-fasted and am-fed conditions, respectively. Dosing at hs led to an exposure that was higher than am-fed but lower than am-fasted dosing. T_max with hs dosing (14 hours) was later than that with am dosing (T_max fasted = 10 hours, fed = 5 hours). Adverse events were mild. There is low systemic exposure of fluticasone propionate with APT-1011. The rate of absorption was increased with a high-fat meal but decreased with hs dosing, suggesting the potential for longer dwell times in the esophagus.

Pharmacokinetic profile analyses for inhaled drugs in humans using the lung delivery and disposition model

The kinetic clarification of lung disposition for inhaled drugs in humans via pharmacokinetic (PK) modeling aids in their development and regulation for systemic and local delivery, but remains challenging due to its multiplex nature. This study exercised our lung delivery and disposition kinetic model to derive the kinetic descriptors for the lung disposition of four drugs [calcitonin, tobramycin, ciprofloxacin and fluticasone propionate (FP)] inhaled via different inhalers from the published PK profile data. With the drug dose delivered to the lung (DTL) estimated from the corresponding γ-scintigraphy or in vivo predictive cascade impactor data, the model-based curve-fitting and statistical moment analyses derived the rate constants of lung absorption (k_a ) and non-absorptive disposition (k_nad ). The k_a values differed substantially between the drugs (0.05-1.00 h^-1 ), but conformed to the lung partition-based membrane diffusion except for FP, and were inhaler/delivery/deposition-independent. The k_nad values also varied widely (0.03-2.32 h^-1 ), yet appeared to be explained by the presence or absence of non-absorptive disposition in the lung via mucociliary clearance, local tissue degradation, binding/sequestration and/or phagocytosis, and to be sensitive to differences in lung deposition. For FP, its k_a value of 0.2 h^-1 was unusually low, suggesting solubility/dissolution-limited slow lung absorption, but was comparable between two inhaler products. Thus, the difference in the PK profile was attributed to differences in the DTL and the k_nad value, the latter likely originating from different aerosol sizes and regional deposition in the lung. Overall, this empirical, rather simpler model-based analysis provided a quantitative kinetic understanding of lung absorption and non-absorptive disposition for four inhaled drugs from PK profiles in humans.

Efficacy and safety of inhaled corticosteroids relative to fluticasone propionate: a systematic review of randomized controlled trials in asthma

INTRODUCTION

Many trials have been published comparing inhaled corticosteroid (ICS) treatments in asthma. However, mixed results necessitate the summarization of available evidence to aid in decision-making. Areas covered: This systematic review evaluated randomized controlled trials (RCTs) that compared the efficacy and safety of inhaled fluticasone propionate (FP) with other ICS including beclomethasone dipropionate (BDP), budesonide (BUD) and ciclesonide (CIC). PubMed was searched and 54 RCTs that fit pre-determined criteria were included. Endpoints evaluated included lung function, asthma symptom control, exacerbation frequency, reliever use, quality of life and steroid-related side effects. Expert commentary: Across all studies, FP was associated with either more favorable or at least similar efficacy and safety, in comparison with BDP or BUD. This observation may be related to FP's higher relative potency and almost negligible oral bioavailability. FP was comparable to CIC for efficacy. However, CIC appeared to have a smaller impact on cortisol levels than FP, which is likely due to CIC's incomplete conversion to active metabolite (des-CIC) and the lower potency of des-CIC compared with FP. Although there were no significant differences in evaluated outcomes after treatment with different ICS in the majority of studies, some observed differences could be explained by their respective pharmacodynamic and pharmacokinetic properties.

Pharmacokinetic Comparison of a Unit Dose Dry Powder Inhaler with a Multidose Dry Powder Inhaler for Delivery of Fluticasone Furoate

BACKGROUND

The unit dose dry powder inhaler (UD-DPI) is being considered as an alternative inhaler platform that, if developed, has the potential to improve access to inhaled respiratory medicines in developing countries.

AIM

This study compared the systemic exposure of fluticasone furoate after delivery from the UD-DPI with that from the ELLIPTA^® inhaler.

METHODS

This open-label, five-way cross-over, randomized, single-dose study in healthy subjects evaluated fluticasone furoate systemic exposure of three dose strengths (using four inhalations), 4 × 80 μg [320 μg], 4 × 100 μg [400 μg], and 4 × 140 μg [560 μg]), and two percentages of drug in lactose blends (0.6% and 0.8% by weight) after delivery from the UD-DPI compared with systemic exposures from the ELLIPTA inhaler (4 × 100 μg [400 μg] dose, 0.8% lactose blend). The primary treatment comparisons were area under the concentration-time curve from time 0 to 6 hours [AUC_0-6] and maximum plasma concentration [C_max].

RESULTS

After single-dose administration of fluticasone furoate, systemic exposure was lower from all UD-DPI formulations versus the ELLIPTA inhaler in terms of both AUC_0-6 [AUC_0-6 geometric least squares mean (GLM) ratios confidence interval (90% CI) for: UD-DPI (400 μg 0.8% blend)/ELLIPTA: 0.61 (0.55-0.67) and C_max GLM (90% CI) for: UD-DPI (400 μg 0.8% blend)/ELLIPTA: 0.56 (0.49-0.64)]. Systemic exposures were ∼10% lower for fluticasone furoate UD-DPI for the 0.8% blend versus the 0.6% blend [GLM ratio (90% CI); 0.90 (0.81-1.00) for AUC_0-6 and 0.89 (0.77-1.01) for C_max], and increasing doses of fluticasone furoate from the UD-DPI showed systemic exposures that were approximately dose proportional. All treatments were well tolerated.

CONCLUSIONS

Fluticasone furoate systemic exposure was lower from the UD-DPI than from the ELLIPTA inhaler, but the UD-DPI formulations did demonstrate detectable systemic levels and approximate dose proportionality. Together with the good tolerability shown, these data support further evaluation of the UD-DPI as a potential device for delivering inhaled respiratory drugs.

Adrenal Insufficiency after Chronic Swallowed Glucocorticoid Therapy for Eosinophilic Esophagitis

OBJECTIVE

To establish the prevalence of adrenal insufficiency (AI) in children with eosinophilic esophagitis treated with swallowed fluticasone propionate (FP) or budesonide.

STUDY DESIGN

Children treated with FP or budesonide for ≥ 6 months underwent a low-dose adrenocorticotropin stimulation test. Patients using systemic, inhaled, intranasal, or topical glucocorticoids were excluded. The primary outcome is AI, defined as peak serum cortisol <18 μg/dL (≤ 495 nmol/L).

RESULTS

Of 58 patients (81% male), 67% were on FP (median age 13.7 years [range 4.3-19.1], dose 1320 μg/d [440-1760], treatment duration 4.0 years [0.6-13.5]). Thirty-three percent were on budesonide (median age 10.7 years [range 3.2-17.2], dose 1000 μg/d [500-2000], treatment duration 3.4 years [0.6-7.7]). The overall prevalence of abnormal peak cortisol response (≤ 20 μg/dL) was 15% (95% CI 6%-25%) (indeterminate [18-20 μg/dL] 5% [n = 3] vs AI [<18 μg/dL] 10% [n = 6]). All patients on budesonide had a normal response vs only 77% of patients on FP (P = .02), all of whom were taking FP at a dose >440 μg/d.

CONCLUSIONS

AI was present in 10% of children treated with swallowed glucocorticoids for ≥ 6 months and was found only in those treated with FP >440 μg/d. We recommend low-dose adrenocorticotropin stimulation testing in children treated long term with high dose FP to allow early detection of AI.

Regulation of YKL-40 expression by corticosteroids: effect on pro-inflammatory macrophages in vitro and its modulation in COPD in vivo

Background

Macrophages constitute a heterogeneous cell population with pro- (MΦ1) and anti-inflammatory (MΦ2) cells. The soluble chitinase-like-protein YKL-40 is expressed in macrophages and various other cell types, and has been linked to a variety of inflammatory diseases, including COPD. Dexamethasone strongly reduces YKL-40 expression in peripheral blood mononuclear cells (PBMC) in vitro. We hypothesized that: a) YKL-40 is differentially expressed by MΦ1 and MΦ2, b) is decreased by corticosteroids and c) that long-term treatment with inhaled corticosteroids (ICS) affects YKL-40 levels in serum and sputum of COPD patients.

Methods

Monocytes of healthy subjects were cultured in vitro for 7 days with either GM-CSF or M-CSF (for MΦ1 and MΦ2, respectively) and stimulated for 24 h with LPS, TNFα, or oncostatin M (OSM). MΦ1 and MΦ2 differentiation was assessed by measuring secretion of IL-12p40 and IL-10, respectively. YKL-40 expression in macrophages was measured by quantitative RT-PCR (qPCR) and ELISA; serum and sputum YKL-40 levels were analyzed by ELISA.

Results

Pro-inflammatory MΦ1 cells secreted significantly more YKL-40 than MΦ2, which was independent of stimulation with LPS, TNFα or OSM (p < 0.001) and confirmed by qPCR. Dexamethasone dose-dependently and significantly inhibited YKL-40 protein and mRNA levels in MΦ1. Serum YKL-40 levels of COPD patients were significantly higher than sputum YKL-40 levels but were not significantly changed by ICS treatment.

Conclusions

YKL-40 secretion from MΦ1 cells is higher than from MΦ2 cells and is unaffected by further stimulation with pro-inflammatory agents. Furthermore, YKL-40 release from cultured monocyte-derived macrophages is inhibited by dexamethasone especially in MΦ1, but ICS treatment did not change YKL-40 serum and sputum levels in COPD. These results indicate that YKL-40 expression could be used as a marker for MΦ1 macrophages in vitro, but not for monitoring the effect of ICS in COPD.

Trial registration

ClinicalTrials.gov, registration number: NCT00158847

Pharmacokinetics, Safety, and Tolerability of a New Fluticasone Propionate Multidose Dry Powder Inhaler Compared With Fluticasone Propionate Diskus(®) in Healthy Adults

BACKGROUND

Fluticasone propionate (Fp) is an inhaled corticosteroid with well-established safety and efficacy profiles. This study evaluated the systemic pharmacokinetics of Fp inhaled from a novel, inhalation-driven multidose dry powder inhaler (MDPI) that does not require coordination of actuation with inhalation.

METHODS

This was a single-center, open-label, randomized, 3-period crossover, single-dose study in healthy Japanese and Caucasian subjects aged 20-45 years, inclusive. Subjects were randomized to one of six treatment sequences including combinations of four inhalations of Fp MDPI 100 μg (400 μg total dose), Fp MDPI 200 μg (800 μg total dose), and Fp Diskus(®) 100 μg (400 μg total dose). The primary objective was to assess pharmacokinetics (maximum plasma concentration [Cmax] and area under concentration-vs.-time curve [AUC]) for each treatment. Safety and tolerability were also assessed.

RESULTS

Thirty subjects (15 Caucasian, 15 Japanese) met entry criteria and were randomized; all 30 subjects completed the study. At the inhaled Fp total doses evaluated (400 and 800 μg), the shapes of plasma concentration-vs.-time curves and systemic exposure (AUC0-t and Cmax) were similar in Japanese and Caucasian subjects. Geometric mean ratios (Japanese/Caucasian) for AUC0-t ranged from 1.11 to 1.15, and for Cmax ranged from 0.90 to 1.05, with no substantial differences between ethnic groups. In both ethnic groups, and in the combined population, systemic exposure (AUC0-t and Cmax) was highest for Fp MDPI 800 μg, followed by Fp MDPI 400 μg, and last by Fp Diskus 400 μg. No clinical laboratory, vital signs, or physical examination findings were considered clinically significant.

CONCLUSIONS

Systemic exposure following inhaled single doses of Fp was comparable in healthy adult Japanese and Caucasian subjects for each total dose and inhaler. The new MDPI provided more efficient drug delivery than Diskus, suggesting that Fp MDPI may provide similar clinical efficacy at a lower inhaled dose compared with Diskus. Single-dose inhaled Fp (400-800 μg) was generally well tolerated in healthy adults.

Eosinophilic esophagitis in children

Eosinophilic esophagitis (EoE) is a relatively common chronic immune-mediated disease of the esophagus characterized clinically by symptoms of esophageal dysfunction that vary by age. Histologically, EoE results in marked esophageal eosinophilia despite treatment with high-dose proton pump inhibition. The cornerstone of treatment is dietary restriction and/or pharmacologic therapy, mainly with topical steroids. This review briefly describes dietary therapy, but focuses on the various medical options in the treatment of EoE, with an emphasis on steroid-based therapy. Numerous landmark studies are reviewed describing the symptomatic and histologic endpoints as well as safety data. The literature strongly supports the use of topical steroid therapy as a means of significantly decreasing eosinophilic mucosal disease. Specifically, high-dose fluticasone propionate appears to be very effective, and has been shown to result in the resolution of mucosal eosinophilia in a large percentage of treated patients. Long-term studies over many years will need to determine whether mucosal healing will change the natural history of this stricture-causing disease. In addition to topical therapy, various other drug-based therapies are reported, including newer immune-based monoclonal antibodies.

Inhaled corticosteroids: potency, dose equivalence and therapeutic index

Glucocorticosteroids are a group of structurally related molecules that includes natural hormones and synthetic drugs with a wide range of anti-inflammatory potencies. For synthetic corticosteroid analogues it is commonly assumed that the therapeutic index cannot be improved by increasing their glucocorticoid receptor binding affinity. The validity of this assumption, particularly for inhaled corticosteroids, has not been fully explored. Inhaled corticosteroids exert their anti-inflammatory activity locally in the airways, and hence this can be dissociated from their potential to cause systemic adverse effects. The molecular structural features that increase glucocorticoid receptor binding affinity and selectivity drive topical anti-inflammatory activity. However, in addition, these structural modifications also result in physicochemical and pharmacokinetic changes that can enhance targeting to the airways and reduce systemic exposure. As a consequence, potency and therapeutic index can be correlated. However, this consideration is not reflected in asthma treatment guidelines that classify inhaled corticosteroid formulations as low-, mid- and high dose, and imbed a simple dose equivalence approach where potency is not considered to affect the therapeutic index. This article describes the relationship between potency and therapeutic index, and concludes that higher potency can potentially improve the therapeutic index. Therefore, both efficacy and safety should be considered when classifying inhaled corticosteroid regimens in terms of dose equivalence. The historical approach to dose equivalence in asthma treatment guidelines is not appropriate for the wider range of molecules, potencies and device/formulations now available. A more robust method is needed that incorporates pharmacological principles.

Pharmacokinetics of fluticasone propionate and salmeterol delivered as a combination dry powder via a capsule-based inhaler and a multi-dose inhaler

AIM

To compare salmeterol (SALM) and fluticasone propionate (FP) systemic exposure following inhaled salmeterol/fluticasone propionate combination (SFC) from a unit-dose capsule-based inhaler (Rotacaps(®)/Rotahaler(®)) and a multi-dose dry powder inhaler (Diskus(®)) in healthy volunteers.

METHODS

An open-label, randomised, repeat-dose, cross-over, adaptive design study (n = 36 in each part) evaluated SFC 50/250 μg and SFC 50/100 μg in Rotacaps used with two types of Rotahaler inhalers (airflow resistance similar to (S) and lower than (L) Diskus) versus the Diskus. Primary endpoints were area under the concentration-time curve over the dosing interval [AUC0-τ] and maximum plasma concentration [Cmax].

RESULTS

SFC 50/250 μg Rotacaps/Rotahaler (S) showed 1.2-1.9-fold greater FP and SALM systemic exposure compared with Diskus. FP and SALM systemic exposure were comparable to DISKUS following SFC 50/250 μg Rotacaps/Rotahaler (L) (90% CI of ratio of Rotahaler to DISKUS within 0.8-1.25) for salmeterol (AUC0-τ and Cmax) and FP (AUC0-τ). Following SFC 50/100 μg Rotacaps/Rotahaler (L), FP and SALM systemic exposures were 1.2-1.4 fold higher in terms of FP (AUC0-τ and Cmax) and salmeterol (Cmax) compared with Diskus. SFC at both doses and via both inhalers was well tolerated.

CONCLUSIONS

SFC 50/250 μg Rotacaps/Rotahaler (L) showed comparable systemic exposure to Diskus in terms of FP AUC and SALM AUC and Cmax. These results merit further progression of SFC 50/250 μg Rotacaps/Rotahaler (L) to phase 3 clinical evaluation in asthma and COPD patients. The lack of pharmacokinetic comparability between the inhalers for SFC 50/100 μg requires further evaluation.

Fluticasone furoate, a novel inhaled corticosteroid, demonstrates prolonged lung absorption kinetics in man compared with inhaled fluticasone propionate

Background

Fluticasone furoate (FF; GW685698) is a novel inhaled corticosteroid that is active at 24 h and under development for once-daily administration in combination with the long-acting β₂-adrenoceptor agonist vilanterol (GW642444) for chronic obstructive pulmonary disease and asthma. In vitro studies examining the respiratory tissue-binding properties of corticosteroids showed FF to have the largest cellular accumulation and slowest rate of efflux compared with other clinically used inhaled corticosteroids, consistent with greater tissue retention. The enhanced affinity of the glucocorticoid receptor binding of FF, coupled with its extended tissue association, may be expected to lead to greater and more prolonged anti-inflammatory effects and should provide relevant once-daily efficacy.

Objective

The aim of this study was to assess the rate and extent of systemic absorption of FF from the lung following inhaled administration of FF from three exploratory dry powder formulations (via DISKHALER^®) compared with inhaled fluticasone propionate (FP) [via DISKHALER^®] using deconvolution analysis.

Methods

This open-label, part-randomized, six-way crossover study evaluated three early development dry powder inhaled formulations of FF administered as single doses via DISKHALER^®. Healthy male subjects (n = 24) each received FF (2,000 μg; three formulations), inhaled FP (1,000 μg; via DISKHALER^®) and 250 μg of each molecule by intravenous infusion. The bioavailability of both inhaled FF and FP represents absorption from the lung as the oral bioavailability from the swallowed portion of the inhaled dose is negligible (<1.5 %). To investigate the absorption kinetics from the lung, the inhaled concentration–time data were subjected to deconvolution analysis using derived pharmacokinetic parameters from fitting of the intravenous concentration–time data.

Results

The terminal elimination half-life (t_½β) for inhaled FF was considerably longer (range 17–24 h) than the t_½β estimated for intravenous FF (14 h), whereas t_½β for FP was similar whether inhaled or given intravenously (11 and 14 h, respectively). This would suggest that FF is exhibiting absorption rate-limited pharmacokinetics following inhaled FF dosing and that the apparent t_½β is an estimate of absorption rate. The lung mean absorption time for FF was approximately 7 h irrespective of formulation, which was considerably longer than FP (2.1 h). The time for 90 % absorption from the lung was significantly longer for FF (20–30 h) than for FP (8 h), indicating a significantly longer lung retention time for FF.

Conclusion

In comparison with inhaled FP, inhaled FF (independent of formulation) demonstrated prolonged absorption from the lung into the systemic circulation, indicating a longer lung retention time and suggesting the potential for maintained efficacy with once-daily administration.

Intranasal Loteprednol Etabonate in Healthy Male Subjects: Pharmacokinetics and Effects on Endogenous Cortisol

Loteprednol etabonate (LE) is a glucocorticoid soft drug that is currently in development for intranasal use. The main objectives of this study were to examine the pharmacokinetics and potential effects on systemic cortisol of two intranasal suspension formulations of LE and to compare these findings with placebo and fluticasone propionate (FP, Flonase) control treatments. In this randomized, double-blind (except for FP), parallel-group study (n = 8/group), all subjects received for 14 days once daily in the morning two puffs of the following nasal spray formulations into each nostril: LE 0.1% (400 microg/day), LE 0.2% (800 microg/day), FP 0.05% (200 microg/day), and placebo. Drug trough levels were determined on days 1, 5, 12, 13, and 14, and a full pharmacokinetic profile was established on day 14, and 24-hour serum cortisol profiles were assessed prior to treatment (i.e., at baseline) and after the last dose. All subjects completed the protocol without treatment-emergent adverse findings. All formulations were rapidly absorbed (t(max) less than 1 h). The rather short mean terminal half-lives of 2.2 +/- 1.5 hours and 1.8 +/- 1.0 hours for LE 400 microg and LE 800 microg, respectively, and 4.2 +/- 1.8 hours for the 200-microg FP treatment explained the lack of any accumulation. Mean peak concentrations (C(max)) were 139 +/- 57 pg/mL with LE 400 microg and 164 +/- 54 pg/mL with LE 800 microg and thus fairly independent from dose. The 200-microg FP treatment resulted in a C(max) of only 15.5 +/- 5.9 pg/mL. Mean measured AUC(0-t) values (193 +/- 87 pg/h/mL(-1), 300 +/- 183 pg/h/mL(-1), and 40 +/- 34 pg/h/mL(-1) for LE 400 microg, LE 800 microg, and FP 200 microg, respectively) showed high variability and suggested nonlinear pharmacokinetics for the LE formulations, indicative of a less complete systemic uptake of LE from the 0.2% concentration. None of the treatments (LE 400 microg, LE 800 microg, and FP 200 microg) showed evidence for serum cortisol suppression when compared with placebo, respectively. The uptake and systemic exposure appears less complete from the 0.2% LE concentration, which principally favors this formulation for further clinical development.

Detection of fluticasone propionate in horse plasma and urine following inhaled administration

Fluticasone propionate (FP) is an anti-inflammatory agent with topical and inhaled applications commonly used in the treatment of asthma in steroid-dependent individuals. The drug is used in racehorses to treat Inflammatory Airway Disease; this work was performed in order to advise on its use and detect potential misuse close to racing. Methods were developed for the extraction and analysis of FP from horse plasma and a carboxylic acid metabolite (FP-17βCOOH) from horse urine. The methods utilize ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) in order to detect the extremely low concentrations of analyte present in both matrices. The developed methods were used to analyse plasma and urine samples collected following inhaled administration of FP to six thoroughbred horses. FP was detected in plasma for a minimum of 72 h post-administration and FP-17βCOOH was detected in urine for approximately 18 h post-administration. The results show that it is possible to detect FP in the horse following inhaled administration.

Topical fluticasone propionate: intervention and maintenance treatment options of atopic dermatitis based on a high therapeutic index

Fluticasone propionate (FP), a medium potent glucocorticoid (class III) of carbothioate nature with a favourable benefit/risk ratio, has emerged as a standard medication for the topical treatment of inflammatory skin disorders, in particular atopic dermatitis (AD). FP is available as a 0.05% cream and a 0.005% ointment formulation. The glucocorticoid is characterized by high lipophilicity, high affinity binding to the glucocorticoid receptor and a rapid hepatic biotransformation. Though skin blanching following topical application of FP surpasses that given with glucocorticoids of medium strength, clinical trials show a low potential of FP for local and systemic adverse effects. Even in paediatric patients with AD as well as in difficult-to-treat areas like face, eyelids and intertriginous areas, FP proved to be both effective and safe. Thus, the therapeutic effects of FP clearly outweigh the unwanted effects. Correspondingly, a therapeutic index of 2.0 can be attributed to this glucocorticoid. In this respect, topical FP does not differ from other topical glucocorticoids with increased benefit-to-risk ratio, e.g. prednicarbate, methylprednisolone aceponate and mometasone furoate. However, randomized controlled trials do not only support conventional intervention but also innovative maintenance treatment.

Bioavailability of inhaled fluticasone propionate via chambers/masks in young children

We determined lung bioavailability of a fluticasone propionate (FP) pressurised metred-dose inhaler (Flovent HFA; GlaxoSmithKline, Research Triangle Park, NC, USA) administered via AeroChamber Plus (Monaghan Medical, Plattsburgh, NY, USA) with Facemask and Babyhaler (GlaxoSmithKline) valved holding chambers (VHCs) using a population pharmacokinetic approach. Children from 1 to <4 yrs of age with stable asthma but a clinical need for inhaled corticosteroid therapy were administered 88 μg FP hydrofluoroalkane (2 × 44 μg) twice daily delivered through the two devices in an open-label, randomised crossover manner for 8 days each. Patients were randomised to one of three sparse sampling schedules for blood collection throughout the 12-h dosing interval on the 8th day of each treatment for pharmacokinetic analysis. The area under the FP plasma concentration-time curve (AUC) was determined for each regimen. 17 children completed the study. The population mean AUC following FP with AeroChamber Plus with Facemask was 97.45 pg·h·mL(-1) (95% CI 85.49-113.32 pg·h·mL(-1)) and with Babyhaler was 51.55 pg·h·mL(-1) (95% CI 34.45-64.46 pg·h·mL(-1)). The relative bioavailability (Babyhaler/AeroChamber Plus) was 0.53 (95% CI 0.30-0.75). Clinically significant differences in lung bioavailability were observed between the devices. VHCs are not interchangeable, as differences in drug delivery to the lung may occur. A population pharmacokinetic approach can be used to determine lung bioavailability of FP.

Comparative pulmonary function and pharmacokinetics of fluticasone propionate and salmeterol xinafoate delivered by two dry powder inhalers to patients with asthma

BACKGROUND

This report presents results of the first human study of a new dry powder inhaler (DPI-C). DPI-C uses reverse flow cyclone technology to retain larger particles in the device and to increase efficiency of respirable drug release. The study was conducted to determine comparative pharmacokinetics (not bioequivalence) of DPI-C and DPI-A (Advair Diskus®, GlaxoSmithKline) and to establish preliminary efficacy and safety of DPI-C.

METHODS

Nineteen patients with mild-moderate asthma received two treatments (randomized crossover design). Treatments were one inhalation from DPI-A labeled to deliver 100 μg fluticasone propionate and 50 μg salmeterol, or one inhalation from DPI-C which contained ∼10% less of each drug per metered dose. Prior to dosing, 10 g of charcoal was administered. FEV1 increase over baseline (measured over 12 h), plasma concentrations of fluticasone and salmeterol (measured over 12.5 h), and occurrence of adverse events were the primary measures of device performance and safety.

RESULTS

Seventeen patients were evaluable. Response profiles of percent increase in FEV1 over baseline showed no statistically significant differences between devices. Peak plasma concentrations of both fluticasone (p=0.003) and salmeterol (p=0.084) were higher from DPI-C. Mean extent of absorption [area under the curve (AUC)] of fluticasone was approximately 30% greater with DPI-C, whereas AUC of salmeterol was approximately 40% greater with DPI-A.

CONCLUSIONS

DPI-C provided similar improvement in pulmonary function compared with DPI-A. Pharmacokinetic results showed a greater initial absorption of salmeterol with DPI-C but greater continued absorption and a 40% greater AUC with DPI-A, which we attribute to slower but more extensive oral absorption because of the greater mass of swallowed large particles of salmeterol generated by DPI-A. No patient reported any treatment-related adverse event or use of rescue medication during this study. Determination of the significance of the observed differences in pharmacokinetics from this single-dose study requires further exploration in studies using clinically relevant dosing regimens.

The influence of inhaled fluticasone on bone metabolism and calciuria in asthmatic children

BACKGROUND

Inhaled corticosteroids have become the first-line medication for treatment of childhood asthma. Possible adverse effects, such as those on bone metabolism and urinary excretion of calcium are in the focus of interest. We investigated the influence of inhaled fluticasone on bone metabolism and renal excretion of calcium, sodium, and potassium in asthmatic children.

METHODS

Thirty asthmatic patients (mean age 12.24 ± 2.75 years) treated with 200-250 μg/day inhaled fluticasone were enrolled in the study. Prior to the initiation of therapy, as well as 12 weeks after following parameters were measured: serum sodium, potassium, calcium, phosphorus, creatinine, alkaline phosphatase, osteocalcin, intact parathyroid hormone levels, first-spot morning urine calcium/creatinine ratio, sodium/potassium ratio, and daily renal calcium excretion rate.

RESULTS

Serum electrolytes, alkaline phosphatase, parathyroid hormone, osteocalcin levels, as well as urinary calcium, sodium, and potassium excretion were within normal ranges. There was no statistical difference between values of those parameters prior and 12 weeks after initiation of the therapy.

CONCLUSIONS

Treatment with 200-250 μg/day inhaled fluticasone, in asthmatic children aged 9-16, during 12 weeks, did not affect serum osteocalcin level and renal excretion of calcium, sodium, and potassium.

The inhaled glucocorticoid fluticasone propionate efficiently inactivates cytochrome P450 3A5, a predominant lung P450 enzyme

Inhaled glucocorticoid (GC) therapy is a vital part of the management of chronic asthma. GCs are metabolized by members of the cytochrome P450 3A family in both liver and lung, but the enzymes are differentially expressed. Selective inhibition of one or more P450 3A enzymes could substantially modify target and systemic concentrations of GCs. In this study, we have evaluated the mechanism-based inactivation of P450 3A4, 3A5, and 3A7 enzymes by GCs. Among the five major inhaled GCs approved for clinical use in the United States, fluticasone propionate (FLT) was the most potent mechanism-based inactivator of P450 3A5, the predominant P450 enzyme in the lung. FLT inactivated P450 3A5 in a time- and concentration-dependent manner with K(I), k(inact), and partition ratio of 16 muM, 0.027 min(-1), and 3, respectively. In contrast, FLT minimally inactivated P450 3A4 and did not inactivate 3A7, even with a concentration of 100 muM. The inactivation of P450 3A5 by FLT was irreversible because dialysis did not restore enzyme activity. In addition, the exogenous nucleophilic scavenger GSH did not attenuate inactivation. The prosthetic heme of P450 3A5 was not modified by FLT. The loss of P450 3A5 activity in lung cells could substantially decrease the metabolism of FLT, which would increase the effective FLT concentration at its target site, the respiratory epithelium. Also, inactivation of lung P450 3A5 could increase the absorption of inhaled FLT, which could lead to high systemic concentrations and adverse effects, such as life-threatening adrenal crises or cataracts that have been documented in children receiving high doses of inhaled GCs.

Salmeterol/fluticasone propionate combination in the treatment of COPD

Chronic obstructive pulmonary disease (COPD) is characterized by poorly reversible airway obstruction and progressive airway inflammation. The long-acting beta2-agonist salmeterol and the corticosteroid fluticasone propionate can be administered in a combination inhaler. Four double-blind, placebo-controlled, randomized clinical trials have demonstrated that salmeterol/fluticasone propionate improves pulmonary function and health status, and also decreases exacerbation rates in COPD patients. The TORCH (Towards a Revolution in COPD Health) study confirmed that the effects of combined therapy with salmeterol/fluticasone propionate are greater than the monocomponents. The TORCH data are also indicative of a beneficial effect of salmeterol/fluticasone propionate on mortality, although there is much debate about this issue. This review critically appraises the pharmacology of salmeterol/fluticasone propionate, the evidence for efficacy in COPD and its potential use in combination with other drugs.

Glucocorticoid-regulated genes in eosinophilic esophagitis: a role for FKBP51

BACKGROUND

Eosinophilic esophagitis (EE) involves marked accumulation of eosinophils in the esophageal mucosa that responds to swallowed fluticasone propionate (FP) in a subset of patients.

OBJECTIVES

We aimed to uncover the mechanism of action of swallowed FP in patients with EE by providing evidence for a topical effect in the esophagus by identifying a molecular signature for FP exposure in vivo.

METHODS

Global microarray expression profiles, immunofluorescence microscopy, and cell signaling in esophageal tissue and cell lines were analyzed.

RESULTS

Thirty-two transcripts exhibited altered expression in patients who responded to swallowed FP treatment. Esophageal FK506-binding protein 5 (FKBP51) mRNA levels were increased (P < .05) in FP responders compared with those seen in control subjects and patients with untreated active EE. After FP treatment of esophageal epithelial cells, FKBP51 mRNA and protein levels were increased in a dose- and time-dependent manner by FP treatment in vitro. FP-induced FKBP51 was steroid receptor dependent because RU486 completely inhibited gene and protein induction. The half-life of FKBP51 mRNA was 16 to 18 hours independent of FP treatment. FKBP51 overexpression reduced FP action as assessed by FP inhibition of IL-13-induced eotaxin-3 promoter activity.

CONCLUSIONS

Our results suggest that swallowed glucocorticoid treatment directly affects esophageal gene expression in patients with EE. In particular, increased FKBP51 transcript levels identify glucocorticoid exposure in vivo and distinguish FP responders from untreated patients with active EE and patients without EE. In addition, FKBP51 reduces glucocorticoid-mediated inhibition of IL-13 signaling in epithelial cells in vitro, suggesting that FKBP51 might influence FP responsiveness. We propose that esophageal FKBP51 levels have diagnostic and prognostic significance in patients with EE.

Pharmacokinetic, pharmacodynamic, efficacy, and safety data from two randomized, double-blind studies in patients with asthma and an in vitro study comparing two dry-powder inhalers delivering a combination of salmeterol 50 microg and fluticasone propionate 250 microg: implications for establishing bioequivalence of inhaled products

BACKGROUND

The use of dry-powder inhalers (DPIs) to administer respiratory medicines is increasing, and new DPIs are likely to be developed because of expiring patents. However, there is considerable debate concerning the extent to which DPIs are interchangeable without altering disease control or the safety profile of the treatment.

OBJECTIVE

This study was designed to compare the pharmacokinetic (PK), pharmacodynamic (PD), efficacy, and safety data for 2 DPIs delivering a combination of salmeterol 50 microg plus fluticasone propionate (FP) 250 microg (SFC 50/250) to investigate assumptions of bioequivalence.

METHODS

Three studies compared SFC 50/250 delivery using a reservoir powder inhalation device (RPID) and a Diskus multiple-dose inhaler: an in vitro assessment of fine-particle-mass (FPM) profiles of the emitted doses; a PK/PD study of SFC 50/250 administered in two 14-day crossover treatment periods to 22 adults with moderate, persistent asthma to determine the equivalence of the RPID and Diskus inhaler in terms of drug delivery and systemic exposure; and a 12-week clinical efficacy and safety study of SFC 50/250 in 270 patients > or =12 years of age with moderate, persistent asthma to assess the equivalence of the RPID and Diskus inhaler based on peak expiratory flow (PEF) rates. FPM was summed from the quantity of active pharmaceutical ingredient deposited on stages 1 to 5 of a cascade impactor, representing an aerodynamic particle size range of 0.8 to 6.2 microm. Systemic exposure to SFC 50/250 was declared no greater with RPID than with the Diskus inhaler if the upper limit of the 90% CI for the ratio of FP AUC for the 2 devices was below the upper limit of the equivalence range (ie, <1.25). Adverse events, clinical laboratory test results, and vital signs were recorded throughout the 2 clinical studies.

RESULTS

In vitro, mean FPM values for the RPID and Diskus inhaler, respectively, were 13.1 and 12.8 microg/dose for salmeterol (P = NS) and 66.8 and 66.2 microg/dose for FP (P = NS). The only notable differences were mean FP for particle sizes 2.3 to 3.2 microm (21.4 microg/dose for RPID, 25.6 microg/dose for Diskus) and for sizes 4.0 to 6.2 microm (17.3 microg/dose for RPID, 11.7 microg/dose for Diskus). In the PK/PD study, there were 22 patients (16 men and 6 women), most (86%) of whom were white. Mean (SD) age was 26.0 (5.0) years (range, 19-35 years), and mean (SD) weight was 67.3 (8.9) kg. The 2 inhalers did not meet the criteria for declaring bioequivalence: estimated ratios (RPID:Diskus) were 2.00 (90% CI, 1.56 to 2.55) for FP AUC up to the time point of next dosing and 1.92 (90% CI, 1.64 to 2.25) for salmeterol maximum observed plasma concentration at the end of the dosing interval (at steady state). Urine cortisol (0-24 hours) was significantly lower for the RPID than for the Diskus inhaler (ratio, 0.74 [95% CI, 0.57 to 0.96]; P = 0.026); no significant difference in plasma cortisol was noted between the 2 inhalers (ratio, 0.85 [95% CI, 0.7 to 1.04]). A small but statistically significant increase in maximum heart rate (5 beats/min) was noted in the RPID group (ratio, 1.05 [95% CI, 1.01 to 1.10]; P = 0.029). No notable differences in other PD end points were observed. Drug-related adverse events occurred in both groups (2 [dysphagia and tremor] in the RPID group and 3 [2 cases of dysphonia, 1 case of mucous-membrane irritation] in the Diskus group). There were 270 patients (136 females, 134 males) in the clinical efficacy and safety study, most (94%) of whom were white; mean (SD) age was 37.2 (17.0) years (range, 11-77 years) in the RPID group and 35.4 (17.2) years (range, 12-77 years) in the Diskus group. The RPID and the Diskus inhaler met the predefined equivalence criteria (+/-15 L/min) in terms of mean change in morning PEF from baseline: 3.9 L/min (95% CI, -3.1 to 11.0). The 2 SFC 50/250 inhalers were well tolerated; the most frequently reported adverse event was bronchitis, reported by 12% of the patients in the RPID group and 9% of those in the Diskus group. The only serious adverse event, which occurred in the RPID group and was related to bronchial infection, was considered unrelated to treatment.

CONCLUSIONS

In vitro particle size distribution data were potentially superimposable for the RPID and the Diskus inhaler. The 2 devices were considered to be clinically equivalent in terms of mean morning PEF but were not considered equivalent in terms of PK systemic exposure. The 2 SFC 50/250 inhalers were well tolerated and had comparable safety profiles; no serious adverse events were attributed to the study product.

Lung bioavailability of hydrofluoroalkane fluticasone in young children when delivered by an antistatic chamber/mask

OBJECTIVE

To determine whether an antistatic valved holding chamber/mask improves lung bioavailability of hydrofluoroalkane (HFA) fluticasone in young children.

STUDY DESIGN

Twelve patients, age 1 to 6 years, with well-controlled asthma were treated with an HFA fluticasone metered-dose inhaler (Flovent HFA) twice daily (440 microg/day). The drug was delivered by tidal breathing through conventional (AeroChamber Plus) and antistatic (AeroChamber MAX) valved holding chambers (VHCs) with masks in a randomized, crossover manner, each for 3 to 7 days. When adherence was 100% at home, blood was collected for measurement of steady-state fluticasone plasma concentration (FPC) 1 hour after the last dose was administered in the clinic. FPC indicates systemic exposure directly and airway delivery indirectly. It was measured by liquid chromatography-mass spectrometry. Data were analyzed by regression analysis.

RESULTS

The mean +/- SD FPC was 107 +/- 30 pg/mL after conventional VHC and 186 +/- 134 pg/mL after the antistatic VHC (P = .03). In 5 patients (40%), the antistatic VHC increased FPC by >/= 100%, to potentially excessive levels in 4 of them; it had little effect in 7 patients.

CONCLUSIONS

HFA fluticasone was delivered to the airways by both devices even though the patients could not inhale deeply and breath hold. The antistatic VHC variably increased lung bioavailability. To reduce systemic exposure, the dose should be weaned to the minimum required to maintain asthma control.

A randomized, double-blind, placebo-controlled trial of fluticasone propionate for pediatric eosinophilic esophagitis

BACKGROUND & AIMS

Eosinophilic esophagitis is an increasingly recognized disorder with distinctive endoscopic, histologic, and allergic features. Although several therapies are advocated, no placebo-controlled trials have been conducted. We aimed to determine the efficacy of swallowed fluticasone propionate (FP) in the treatment of eosinophilic esophagitis.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial of swallowed FP in pediatric patients with active eosinophilic esophagitis. Thirty-six patients were randomly assigned to receive either 880 mug of FP (21 patients) or placebo (15 patients) divided twice daily for 3 months. The primary end point was histologic remission, defined by a peak eosinophil count of </=1 eosinophil in all 400x fields in both the proximal and distal esophagus.

RESULTS

Fifty percent of FP-treated patients achieved histologic remission compared with 9% of patients receiving placebo (P = .047). FP decreased esophageal eosinophil levels, with a more pronounced effect in nonallergic individuals (65.9 +/- 25.3 vs 1.4 +/- 1.1 eosinophils/high-power field in the proximal esophagus [P = .03] and 84.6 +/- 19.7 vs 19.6 +/- 12.9 eosinophils/high-power field in the distal esophagus [P = .04]). Resolution of vomiting occurred more frequently with FP than placebo (67% vs 27%; P = .04). FP-induced resolution of mucosal eosinophilia was associated with resolution of endoscopic findings, epithelial hyperplasia, younger age (P = .0003), shorter height (P = .002), and lighter weight (P = .02). Effective treatment with FP decreased the number of CD8(+) T lymphocytes and mast cells in both the proximal and distal esophagus (P < .05).

CONCLUSIONS

Swallowed FP is effective in inducing histologic remission in eosinophilic esophagitis, with a more pronounced effect in nonallergic and younger individuals, especially in the proximal esophagus.

Plasma concentrations of inhaled corticosteroids in relation to airflow obstruction in asthma

AIMS

To compare the pharmacokinetic profiles of beclometasone, budesonide, fluticasone and mometasone following inhalation in patients with asthma, and explore the relationship between lung function and plasma drug concentrations.

METHODS

Thirty subjects with asthma and a forced expiratory volume in 1 s (FEV(1)) ranging from 36 to 138% predicted, inhaled 800 microg beclometasone, budesonide and mometasone and 1000 microg fluticasone in random order. Plasma drug concentrations were measured over 8 h and the relationship between the area under the plasma concentration-time curve (AUC(0-8)) and lung function was modelled using linear regression. Estimated AUC(0-8) values at 50 and 100% predicted FEV(1) were compared for each drug.

RESULTS

Pharmacokinetic profiles differed markedly between the drugs. Correlation coefficients for the relation between FEV(1)% predicted and AUC(0-8) values for beclometasone, budesonide, fluticasone and mometasone were 0.37 (P = 0.05), 0.33 (P = 0.08), 0.25 (P = 0.2) and 0.52 (P = 0.004), respectively, and estimated AUC(0-8) values were 1.3 [95% confidence interval (CI) 1.0, 1.8], 1.3 (95% CI 1.0, 1.8), 1.4 (95% CI 0.9, 2.2) and 2.2 (95% CI 1.3, 3.5) times higher for the four drugs, respectively, at 100 compared with 50% predicted FEV(1.)

CONCLUSION

The higher plasma concentrations of inhaled corticosteroids in patients with a higher FEV(1)% predicted suggests that, for any given dose, these patients will be at greater risk of developing adverse systemic effects with long-term use.

Benefit versus risk for oral, inhaled, and nasal glucocorticosteroids

Many factors affect the benefit-to-risk analysis of the use of the glucocorticosteroids in the treatment of allergic inflammation. For most patients the benefit-to-risk ratio favors topical over oral administration, but in severe disease oral administration may be required. It is clear from pharmacokinetic and pharmacodynamic studies that inhaled glucocorticosteroids in particular are absorbed into the systemic circulation and that they can have clinical adverse effects when given in high doses. Therefore, with inhaled and nasal glucocorticosteroids, the dose that will achieve the optimal benefit/risk ratio is the lowest dose that controls symptoms and prevents exacerbations requiring treatment with oral glucocorticosteroids. This optimal dose needs to be determined on an individual basis and is likely to vary as disease severity changes over time.

Effects of inhaled ciclesonide and fluticasone propionate on cortisol secretion and airway responsiveness to adenosine 5'monophosphate in asthmatic patients

The efficacy and systemic effects of ciclesonide, a novel glucocorticosteroid, inhaled via pressurized metered-dose inhaler (pMDI) were compared with fluticasone propionate pMDI in 26 patients with asthma, using a randomized, double blind, placebo-controlled, double dummy, 6-period crossover study design. Treatments were placebo, ciclesonide 320 microg (ex-actuator dose) once daily (o.d.), ciclesonide 640 microg o.d., ciclesonide 640 microg twice daily (b.i.d.), fluticasone propionate 440 microg (ex-actuator dose) b.i.d., and fluticasone propionate 880 microg b.i.d. The primary variable was area under the plasma cortisol concentration-time curve over 24 h (plasma cortisol AUC(0-24), relative to placebo) derived from samples taken every 2 h, on the 9th day of treatment. Secondary variables were 24-h urinary cortisol excretion and PC20 for adenosine 5'-monophosphate (AMP) (relative to placebo and expressed in doubling concentrations). Ciclesonide did not affect 24-h cortisol secretion. Fluticasone propionate suppressed cortisol secretion as demonstrated by a decrease in plasma cortisol AUC(0-24), relative to placebo, by 29% (95% CI 15-41) and 59% (95% CI 51-66) with 440 and 880 microg b.i.d., respectively. PC20 more than doubled with each active treatment, but no statistically significant dose-response effect could be established. It was concluded that moderate to high doses of fluticasone propionate suppressed cortisol secretion, that ciclesonide did not suppress cortisol secretion, and that all active treatments decreased hyperresponsiveness to AMP.

Adrenal Suppression with Dry Powder Formulations of Fluticasone Propionate and Mometasone Furoate

Mometasone furoate (MF) and fluticasone propionate (FP) are high potency inhaled corticosteroids. The systemic bioavailability of MF is claimed to be negligible, leading to a minimal potential for systemic adverse effects. We assessed the overnight urinary cortisol/creatinine as the primary outcome of adrenal suppression in 21 patients with persistent asthma (mean FEV1 = 91%). Patients were randomized in a crossover fashion to receive 2 weekly consecutive doubling incremental doses of either FP Accuhaler (500, 1,000, and 2,000 microg/day) or MF Twisthaler (400, 800, and 1,600 microg/day). For the 21 per protocol completed patients, there was significant suppression of overnight urinary cortisol/creatinine with high and medium doses of both drugs-as geometric mean fold suppression (95% confidence interval) from baseline: FP 2,000 microg, 1.85 (1.21-2.82, p = 0.002); FP 1,000 microg, 1.45 (1.07-1.96, p = 0.02); MF 1,600 microg, 1.92 (1.26-2.93, p = 0.001); and MF 800 microg, 1.39 (1.04-1.88, p = 0.02). For secondary outcomes of 8:00 A.M. plasma cortisol, serum osteocalcin, and early morning urinary cortisol/creatinine, there was significant suppression with MF and FP at the highest dose. Our data refute the assertion that MF has negligible systemic bioavailability and a lower potential for systemic adverse effects compared with FP.

Deposition and effects of inhaled corticosteroids

Inhaled corticosteroids are now recommended as maintenance therapy for all but the mildest cases of asthma, and may be delivered by a variety of devices and formulations. Drug delivery may be assessed by both in vitro and in vivo methods. Although drug deposition in the lungs is expected to predict clinical response, this relationship is often masked by the flat nature of corticosteroid dose-response curves. The effects of inhaled corticosteroids depend not only upon the pharmacology of the drug being administered, but also upon its delivery system, with more efficient devices not only improving therapeutic effect but also potentially increasing systemic adverse effects. Modern delivery systems that enhance drug targeting to the lungs make it possible to use lower dosages of inhaled corticosteroid, such that the clinical response is maintained but systemic exposure reduced.

Pharmacokinetics and systemic effects of inhaled fluticasone propionate in chronic obstructive pulmonary disease

AIMS

We have previously shown that the systemic exposure to inhaled fluticasone propionate (FP) is reduced in asthmatics compared with healthy subjects. We have now compared its pharmacokinetics in patients suffering from chronic obstructive pulmonary disease (COPD, n = 10) and matched healthy subjects (n = 13).

METHODS

A double-blind, randomized, cross-over study design was used. Plasma FP and serum cortisol were measured for 12 h after subjects received hydrofluoroalkane FP 1000 microg day-1 inhaled (via an MDI and spacer) for 7 days and following a single 1000- microg intravenous dose.

RESULTS

The pharmacokinetics differed in the two groups. After inhalation, geometric least square means were significantly lower in the COPD group for the plasma AUC (1961 vs 2996 pg ml-1 h-1 for COPD and controls, respectively; P = 0.03) and the Cmax (235 vs 421 pg ml-1 for COPD and controls, respectively; P = 0.03). Suppression of serum cortisol concentration over 12 h was greater in healthy controls. Weighted mean serum cortisol concentration (nmol l-1) in healthy subjects and COPD was 93 and 170, respectively (P = 0.03). The intravenous pharmacokinetic parameters for FP were comparable in the two groups, resulting in similar suppression of serum cortisol.

CONCLUSIONS

We conclude that the altered pharmacokinetics of inhaled fluticasone propionate in COPD caused less hypothalamic-pituitary-adrenal suppression than in healthy controls. This is further evidence that the systemic effects of inhaled corticosteroids should be assessed in patients and not healthy subjects.

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.