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OBJECTIVE: Teduglutide is a recombinant analogue of human glucagonlike peptide-2 (GLP-2) that was recently approved by the US and European regulatory agencies FDA and EMA for the treatment of short bowel syndrome (SBS). The objectives of this work were, firstly, to develop a population pharmacokinetic (popPK) model based on the available PK data of the entire clinical development program and, secondly, to utilize the model for the justification of the proposed dosing regimen. The exploratory analysis was based on a previously established structural PK model and focused primarily on the investigation of covariate effects. RESULTS: The plasma concentrationtime profiles of teduglutide after subcutaneous application were adequately described by a 1-compartment model with first order absorption and elimination. The area under the curve (AUC) was lower for male subjects, for subjects with higher creatinine clearance, for overweight subjects, and for SBS patients. However, except for subjects with severe renal impairment no clinically relevant effects on AUC were identified. CONCLUSION: Our model-based analysis supports the approved dose adjustment for SBS patients with and without renal impairments maintaining the exposure in a value range with acceptable variance for the target population.

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CONTEXT: Intranasal fentanyl spray (INFS) was developed for the treatment of breakthrough pain in cancer patients using an alternative route of administration. OBJECTIVE: The aim of this clinical study was to investigate the pharmacokinetic (PK) profile and bioavailability of INFS in healthy subjects compared to oral transmucosal fentanyl citrate (OTFC). MATERIALS AND METHODS: In a randomized, single-center, open-label, two-way crossover PK study, 24 subjects (12 male, 12 female, mean age 25.2 years) received INFS (single-dose delivery system 200 µg/100 µl) and OTFC (buccal lozenge, 200 µg). Naltrexone was given to prevent potential adverse reactions. Frequent plasma samples were taken up to 96 h and analyzed by LC-MS/MS with a lower limit of quantitation of 25 pg/ml. Primary PK parameter was the area under the fentanyl plasma concentration-time curve (AUC(0-inf)). RESULTS: Compared to OTFC, a much faster absorption rate was observed for INFS which was supported by the much earlier appearance of detectable fentanyl plasma levels and a shorter T(max). At 15 min post-dose, the mean plasma fentanyl levels reached 602 pg/ml for INFS and 29 pg/ml for OTFC. Significantly higher C(max) and AUC values were obtained with INFS compared to OTFC. Although administered for 15 min, consumption of OTFC was incomplete in many incidences (∼70%) upon visual inspection. No safety concerns were identified for fentanyl administration in combination with oral naltrexone. DISCUSSION AND CONCLUSION: One dose of INFS gives significantly higher plasma fentanyl levels and significantly higher bioavailability than OTFC based on dose-normalized AUC.

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Asthma continues to be a global health problem and currently available treatments such as corticosteroids can cause unwanted side effects. Inhaled corticosteroids (ICS) are recommended as first-line therapy for reducing airway inflammation and have a distinct advantage over oral preparations as they provide a direct route of delivery to the lungs. However, local deposition of ICS in the oropharynx can lead to oral candidiasis, dysphonia, and pharyngitis. The pharmaceutical quality is a primary concern of any ICS asthma treatment, with a higher quality product resulting in improved efficacy and safety profiles. The particle size distribution and the spray force velocity of an ICS may directly influence lung deposition, and the spray duration of a device is another important factor when coordinating inhalation. Recent advances in ICS device and formulation technology have resulted in significant improvements in the efficacy of available asthma treatments. In particular, hydrofluoroalkane (HFA) solution technology and the development of smaller particle sizes have resulted in the production of new ICS formulations that have the ability to directly target drug delivery to the site of airway inflammation. Both the ICS formulation and the pressurized metered-dose inhaler device used to administer ciclesonide (CIC) HFA have been developed to treat the underlying chronic inflammation associated with asthma. CIC is administered as a prodrug which is activated in the lungs, leading to minimal oropharyngeal deposition. The small particle size of CIC results in the delivery of a high fraction of respirable particles to the small airways of the lungs, resulting in high lung deposition and continual dose consistency. This review summarizes how CIC administered as an HFA formulation is an effective treatment for asthma.

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Ciclesonide hydrofluoroalkane nasal aerosol (CIC-HFA) is currently in development for treatment of allergic rhinitis. This Phase I study evaluated the pharmacokinetics, pharmacodynamics, safety, and tolerability of CIC-HFA in healthy subjects (N = 18) and subjects with perennial allergic rhinitis (PAR, N = 18) in a double-blind, placebo-controlled, 3-period crossover design following treatment with 282 µg or 148 µg CIC-HFA or placebo once-daily for 14 days. The concentrations of desisobutyryl-ciclesonide (des-CIC), the pharmacologically active metabolite of CIC were measured by a validated high performance liquid chromatography with tandem mass spectrometry. Maximum serum concentration (C(max)), area under the serum concentration time curve (AUC), time to maximum serum concentration (t(max)) and elimination half life (t(1/2)) where feasible, were calculated. Serum cortisol (AUC(0-24h)) and adverse events (AE) were also evaluated. The overall systemic exposure of des-CIC was low. The mean C(max) for des-CIC on Day 14 was 35.84 ng/L and 25.98 ng/L for the CIC-HFA 282 µg and CIC-HFA 148 µg treatment groups respectively. Mean AUC((0, last)) for des-CIC on Day 14 was 213 ng·h/L and 112.3 ng·h/L for CIC-HFA 282 µg and 148 µg respectively. Mean serum cortisol (AUC(0-24h)) was similar for CIC-HFA 282 µg (178 µg·h/dL), CIC-HFA 148 µg (169 µg·h/dL), and placebo (174 µg·h/dL) on Day 14. The overall incidence of AEs was low and headache and epistaxis were the most common individual AEs reported. In this study, systemic exposure of des-CIC was low and similar in healthy subjects and subjects with PAR with no evidence of clinically relevant accumulation over the 14 day treatment period in either treatment group. Both doses of CIC-HFA were well tolerated without significant effect on cortisol levels.

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BACKGROUND: Ciclesonide, an intranasal corticosteroid, is administered as a prodrug and is converted to the active metabolite, desisobutyryl ciclesonide, in the upper and lower airways. Previous studies have assessed systemic exposure with the ciclesonide hydrofluoroalkane metered dose inhaler (CIC HFA-MDI) and the ciclesonide aqueous nasal spray (CIC-AQ) formulations. However, systemic exposure with ciclesonide HFA nasal aerosol (CIC-HFA) developed for the treatment of allergic rhinitis has not been investigated. OBJECTIVE: This study compared the systemic exposure of ciclesonide and desisobutyryl ciclesonide after administration of ciclesonide formulated as an aqueous nasal spray, an HFA nasal aerosol, or as an orally inhaled HFA-MDI. METHODS: Healthy adults (aged 18-60 years) were randomly assigned in an open-label, singledose, 3-period crossover design to CIC-AQ 300 microg, CIC-HFA 300 microg, or CIC HFA-MDI 320 microg. Serum samples were collected before study drug administration and at 5, 15, and 30 minutes and 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 14, 18, 22, and 24 hours after dosing. The primary pharmacokinetic parameters were AUC(0-infinity) and C(max) of desisobutyryl ciclesonide. Adverse events were elicited by direct questioning of participants throughout the study. RESULTS: Thirty volunteers were randomly assigned. Most of the volunteers were male (63% [19/30]) and white (83% [25/30]); the mean age was 36 years and mean weight was 68 kg. Concentrations of desisobutyryl ciclesonide were quantifiable (lower limit of quantitation [LLOQ] = 10 ng/L) in the serum samples of only 5 volunteers (of 30) receiving CIC-AQ, and the highest C(max) value of desisobutyryl ciclesonide was 26.7 ng/L (mean C(max), 15.2 ng/L). The AUC(0-infinity) of desisobutyryl ciclesonide for CIC-AQ was below the LLOQ of the bioanalytic assay. Mean C(max) and AUC(0-infinity) of desisobutyryl ciclesonide were 59.1 ng/L and 397.5 ng . h/L, respectively, for CIC-HFA; and 586.2 ng/L and 2685.0 ng . h/L, respectively, for CIC HFA-MDI. Concentrations of the parent compound, ciclesonide, were below the LLOQ in serum samples after administration of CIC-AQ; they were detectable up to 2 hours after administration of CIC-HFA and up to 4 hours after administration of CIC HFA-MDI. Treatment-emergent adverse events occurred with a low frequency in all 3 treatment groups (30% [9/30] overall) and were mild in intensity as determined by the study investigator. CONCLUSIONS: In this study, compared with that of CIC HFA-MDI, the systemic exposure of desisobutyryl ciclesonide was 10-fold lower after administration of CIC-HFA and at least 40-fold lower after administration of CIC-AQ. All treatments were well tolerated.

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Ciclesonide is a novel corticosteroid (CS) for the treatment of asthma and allergic rhinitis. After administration, the parent compound ciclesonide is converted by intracellular airway esterases to its pharmacologically active metabolite desisobutyryl-ciclesonide (des-CIC). We investigated the in vitro activation of ciclesonide and further esterification of des-CIC to (mainly) des-CIC oleate in several human target organ test systems. Human precision-cut lung slices, alveolar type II epithelial cells (A549), normal bronchial epithelial cells (NHBE), and nasal epithelial cells (HNEC) were incubated with ciclesonide. Enzymes characterization and the determination of the reversibility of fatty acid esterification was investigated in HNEC and NHBE. Ciclesonide was taken up and converted to des-CIC in all cellular test systems. Intracellular concentrations of des-CIC were maintained for up to 24 h. Formation of des-CIC oleate increased over time in HNEC, A549 cells, and lung slices. The formed des-CIC fatty acid conjugates were reconverted to des-CIC. Increasing concentrations of carboxylesterase and cholinesterase inhibitors progressively reduced the formation of metabolites. The results derived from these studies demonstrate the activation of ciclesonide to des-CIC in the upper and lower airways. The reversible formation of des-CIC fatty acid conjugates may prolong the anti-inflammatory activity of des-CIC and may allow for once-daily dosing.

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BACKGROUND: The therapeutic effect of inhaled corticosteroids (ICS) may be affected by the metabolism of the drug in the target organ. We investigated the in vitro metabolism of beclomethasone dipropionate (BDP), budesonide (BUD), ciclesonide (CIC), and fluticasone propionate (FP) in human lung precision-cut tissue slices. CIC, a new generation ICS, is hydrolyzed by esterases in the upper and lower airways to its pharmacologically active metabolite desisobutyryl-ciclesonide (des-CIC). METHODS: Lung tissue slices were incubated with BDP, BUD, CIC, and FP (initial target concentration of 25 microM) for 2, 6, and 24 h. Cellular viability was assessed using adenosine 5'-triphosphate content and protein synthesis in lung slices. Metabolites and remaining parent compounds in the tissue samples were analyzed by HPLC with UV detection. RESULTS: BDP was hydrolyzed to the pharmacologically active metabolite beclomethasone-17-monopropionate (BMP) and, predominantly, to inactive beclomethasone (BOH). CIC was hydrolyzed initially to des-CIC with a slower rate compared to BDP. A distinctly smaller amount (approximately 10-fold less) of fatty acid esters were formed by BMP (and/or BOH) than by BUD or des-CIC. The highest relative amounts of fatty acid esters were detected for BUD. For FP, no metabolites were detected at any time point. The amount of drug-related material in lung tissue (based on initial concentrations) at 24 h was highest for CIC, followed by BUD and FP; the smallest amount was detected for BDP. CONCLUSION: The in vitro metabolic pathways of the tested ICS in human lung tissue were differing. While FP was metabolically stable, the majority of BDP was converted to inactive polar metabolites. The formation of fatty acid conjugates was confirmed for BMP (and/or BOH), BUD, and des-CIC.

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BACKGROUND: The nasal tissue uptake and metabolism of ciclesonide, a new-generation corticosteroid under investigation for treatment of allergic rhinitis, to its active metabolite, desisobutyryl-ciclesonide (des-CIC), was evaluated when administered to rabbits in a hypotonic versus an isotonic ciclesonide suspension. Nasal mucosa extracts from normal Japanese white rabbits were evaluated by high-performance liquid chromatography with tandem mass spectrometry detection after a single 143-mug dose of ciclesonide. Retention and formation of fatty acid conjugates of des-CIC were also measured in nasal mucosa extracts postadministration of a hypotonic ciclesonide suspension (143-mug single dose). RESULTS: Versus an isotonic suspension, the hypotonic suspension achieved higher concentrations of des-CIC (5.6-fold, 11.4-fold, and 13.4-fold; p < 0.05 for all) and ciclesonide (25.3-fold, 34.2-fold [p = not significant], and 16-fold [p < 0.05]) at 30, 120, and 240 min postadministration. Additionally, when administered via a hypotonic suspension, des-CIC was retained up to 24 h postadministration (45.46 pmol/g tissue). Highest concentration of major fatty acid ester conjugate, des-CIC-oleate, was detected in nasal mucosa at 8 h postadministration. CONCLUSION: These data suggest that a hypotonic ciclesonide suspension provides higher intracellular concentrations of des-CIC up to 24 h, thereby providing a rationale for investigation of ciclesonide as a convenient once-daily nasal spray for treatment of allergic rhinitis.

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The in vitro metabolism of ciclesonide, a novel inhaled nonhalogenated glucocorticoid for the treatment of asthma, was compared in cryopreserved hepatocytes from mice, rats, rabbits, dogs, and humans. Incubations of C-ciclesonide with individual hepatocyte suspensions revealed similar metabolite profiles in all 5 in vitro systems used. Ciclesonide was rapidly converted to its active metabolite, desisobutyryl-ciclesonide (des-CIC). Des-CIC was then extensively metabolized to pharmacologically inactive metabolites through oxidation and reduction, followed by glucuronidation. A total of 12 groups of metabolites derived from des-CIC were characterized and identified by liquid chromatography/radioactivity monitor/mass spectrometry. Oxidation occurred on both the cyclohexane ring and the steroid moiety. Hippuric acid formation by cleavage of the cyclohexylmethyl moiety of ciclesonide, followed by aromatization of the cyclohexane ring through multiple steps of hydroxylation, dehydration, and conjugation with glycine, was found in rat, rabbit, and human hepatocyte incubations. The results indicated that ciclesonide and its active metabolite, des-CIC, were extensively metabolized in vitro in animal and human hepatocytes and that the metabolite profiles in mouse, rat, rabbit, and dog hepatocytes were similar to the profiles in human hepatocytes.

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Ciclesonide (CIC) is an inhaled glucocorticosteroid. This study aimed to identify esterases involved in the metabolism of CIC to the active metabolite desisobutyryl-ciclesonide (des-CIC), and to measure hydrolysis rates in human liver, lung and plasma and normal human bronchial epithelial (NHBE) cells in vitro. Ciclesonide (5 microM and 500 microM) was incubated with microsomal or cytosolic fractions from liver, lung and plasma (n=4 for each) and des-CIC formation was determined by reverse-phase high-performance liquid chromatography with U.V. detection. The roles of carboxylesterase, cholinesterase and A-esterase in CIC hydrolysis were determined using a range of inhibitors. Inhibitor concentrations for liver and NHBE cells were 100 microM and 5 microM, respectively. Liver tissue had a higher activity for 500 microM CIC hydrolysis (microsomes: 25.4; cytosol: 62.9 nmol/g tissue/min) than peripheral lung (microsomes: 0.089; cytosol: 0.915 nmol/g tissue/min) or plasma (0.001 nmol/mL plasma/min), corresponding with high levels of carboxylesterase and cholinesterase in the liver compared with the lung. CIC (5 microM) was rapidly hydrolyzed by NHBE cells (approximately 30% conversion at 4h), with almost complete conversion by 24h. In liver and NHBE cells, major involvement of cytosolic carboxylesterases, with some contribution by cholinesterases, was indicated. The highest level of conversion was found in the liver, the site of inactivation of des-CIC through rapid oxidation by cytochrome P450. Carboxylesterases in bronchial epithelial cells probably contribute significantly to the conversion to des-CIC in the target organ, whereas low systemic levels of des-CIC are a result of the high metabolic clearance by the liver following CIC inhalation.

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Ciclesonide, a corticosteroid in development for allergic rhinitis, is converted to the pharmacologically active metabolite, desisobutyryl-ciclesonide (des-CIC), and des-CIC is subsequently esterified with fatty acids. Various experiments were performed to investigate ciclesonide metabolism in human nasal epithelial cells (HNEC). Human nasal epithelial cells were incubated with (a) 0.1 microM ciclesonide for 1 h and medium without ciclesonide for up to 24 h, (b) esterase inhibitors for 0.5 h followed by 5 microM ciclesonide for 6 h, or (c) 1 microM des-CIC for 6 h followed by medium without des-CIC for up to 24 h. Ciclesonide, des-CIC and des-CIC fatty acid conjugate concentrations were determined by high-performance liquid chromatography with tandem mass spectrometry. The amount of ciclesonide in HNEC decreased approximately 93-fold from 0.5 to 24 h. In contrast, des-CIC was present at constant levels throughout the post-treatment period. Furthermore, fatty acid conjugates of des-CIC were retained in HNEC up to 24 h post-treatment. Carboxylesterase and cholinesterase inhibitors decreased ciclesonide metabolism > or =50%. The total amounts of des-CIC fatty acid conjugates decreased and the extracellular amounts of des-CIC increased with time. In conclusion, ciclesonide was rapidly converted to des-CIC by carboxylesterases and cholinesterases, and des-CIC underwent reversible fatty acid conjugation in HNEC.

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BACKGROUND: Ciclesonide is an inhaled corticosteroid that provides safe and effective control of persistent asthma. Ciclesonide is administered as an aerosol solution in a metered-dose inhaler, using hydrofluoroalkane-134a as a propellant. It is activated in the lung to form its only active metabolite, desisobutyryl-ciclesonide (des-CIC). A spacer may be used in combination with the hydrofluoroalkane metered-dose inhaler (HFA-MDI) to maintain inhaled corticosteroid delivery to the lung in patients with poor inhalation technique. OBJECTIVE: To determine if the pharmacokinetics of des-CIC and ciclesonide are altered when a spacer is used for ciclesonide inhalation. METHODS: A randomised, open-label, 2-period crossover, single-center pharmacokinetic study was conducted in 30 patients with asthma (forced expiratory volume in 1 second > or = 70% predicted). A single dose of ciclesonide (320 microg ex-actuator; equivalent to 400 microg ex-valve) was administered via the HFA-MDI with and without an AeroChamber Plus spacer (Trudell Medical International, London, ON, Canada). Serum concentrations of ciclesonide and des-CIC were measured before inhalation and at various intervals until 14 hours after treatment using high-performance liquid chromatography with tandem mass spectrometric detection. RESULTS: The pharmacokinetic properties of the active metabolite, des-CIC, were equivalent after inhalation of ciclesonide with and without the AeroChamber Plus spacer. Point estimates and 90% confidence intervals (CIs) for the ratio of des-CIC pharmacokinetic properties in the presence or absence of a spacer were within the conventional bioequivalence range of 0.80-1.25 (area under the serum concentration time curve from time zero to infinity 0.96 [0.85, 1.07]; peak serum concentration 1.05 [0.94, 1.18]; elimination half-life 1.04 [0.92, 1.18]). Furthermore, there was no relevant difference in the point estimate and 90% CI of the difference of the time to reach peak serum concentration of des-CIC with or without a spacer. CONCLUSION: The AeroChamber Plus spacer did not influence the pharmacokinetics of the pharmacologically active des-CIC. Thus, systemic exposure to the active metabolite is similar when ciclesonide is inhaled with or without a spacer. Furthermore, these results are indicative of comparable lung deposition of ciclesonide in both the presence and absence of a spacer.

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Ciclesonide is a new-generation inhaled corticosteroid developed to treat the inflammation associated with persistent asthma. In order to identify the properties of ciclesonide responsible for anti-inflammatory activity, ciclesonide metabolism was investigated in human lung and liver precision-cut tissue slices. Three human lung and three human liver tissue slices were incubated with 25 microM [14C]-ciclesonide for 2, 6 and 24 h. Cellular viability was assessed using adenosine 5'-triphosphate content and protein synthesis in lung slices and adenosine 5'-triphosphate content and potassium retention in liver slices. Ciclesonide and ciclesonide metabolites were analysed in tissue samples using high-performance liquid chromatography with ultraviolet and radiochemical detection. Metabolite identity was confirmed using mass spectrometry. In lung slices, the inactive parent compound, ciclesonide, was initially converted to the active metabolite, desisobutyryl-ciclesonide, and subsequently converted to fatty acid conjugates. The reversible formation of fatty acid conjugates was a major pathway of ciclesonide metabolism in human lung slices. The primary conjugate was identified as desisobutyryl-ciclesonide oleate. Ciclesonide was metabolized to at least five polar metabolites in the liver. Dihydroxylated desisobutyryl-ciclesonide was the major polar metabolite in liver slices. Activation and fatty acid esterification in the lung followed by rapid inactivation in the liver may explain the improved safety profile and prolonged anti-inflammatory activity of ciclesonide.

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Ciclesonide is an intranasal corticosteroid in development for the treatment of allergic rhinitis. To assess the safety, tolerability, and pharmacokinetics of ciclesonide, adult healthy volunteers and asymptomatic subjects with seasonal allergic rhinitis were randomized to receive intranasal ciclesonide or placebo for 14 days. Serum concentrations of ciclesonide and its active metabolite, desisobutyryl-ciclesonide, were measured using high-performance liquid chromatography assay with tandem mass spectrometric detection, with lower limits of quantification of 25 and 10 pg/mL, respectively. Adrenal function was monitored by diurnal serum free and 24-hour urine cortisol concentrations. Despite the use of a sensitive assay and a high ciclesonide dose (800 microg/d), serum levels of ciclesonide and desisobutyryl-ciclesonide were below the lower limits of quantification for the majority of samples assayed. Ciclesonide was well tolerated and did not appear to affect serum or urine free cortisol levels. The low systemic exposure and favorable safety profile support the continued clinical development of ciclesonide nasal spray.

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OBJECTIVE: To examine the deposition and pharmacokinetics of ciclesonide administered via hydrofluoroalkane-metered dose inhaler (HFA-MDI) in patients with asthma. METHODS: Twelve patients with mild asthma (FEV1, 95% predicted) inhaled a single dose of 99mtechnetium (Tc)-ciclesonide 320 microg ex-actuator (400 microg ex-valve). Deposition of ciclesonide in the lung and oropharynx was quantified using two-dimensional (2D)-gamma scintigraphy. Three-dimensional single photon emission computed tomography (3D SPECT) was used to assess the regional distribution of ciclesonide in the lung. The pharmacokinetics of ciclesonide and its active metabolite, desisobutyryl-ciclesonide (des-CIC), were determined by liquid chromatography-tandem mass spectrometry. Ciclesonide and des-CIC concentrations were determined in mouth-rinsing solutions. RESULTS: 2D-gamma scintigraphy indicated that ciclesonide deposition was higher in the whole lung (52%) than in the oropharynx (32.9%). Furthermore, 3D SPECT revealed that ciclesonide deposition within the lungs was highest in the peripheral regions that contain the small airways and alveoli. The pharmacokinetic profile of Tc-labeled ciclesonide and des-CIC was similar to that obtained after inhalation of non-labeled formulations in previous studies. Des-CIC accounted for 14.9% of the total molar concentration of ciclesonide/des-CIC in mouth-rinsing solutions obtained between 7 and 12min after inhalation. CONCLUSION: Inhalation of ciclesonide via HFA-MDI results in high pulmonary deposition, especially in the peripheral regions of the lung. High pulmonary deposition contributes to ciclesonide's ability to maintain lung function and control symptoms in patients with asthma. Deposition and activation of ciclesonide in the oropharynx is low, consistent with previous reports of low oropharyngeal deposition and a reduced incidence of local side effects in patients receiving ciclesonide therapy.

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Freely circulating, protein unbound, active inhaled corticosteroid (ICS) can cause systemic adverse effects. Desisobutyryl-ciclesonide (des-CIC) is the active metabolite of ciclesonide, an effective, novel ICS for persistent asthma. This study examines the free fraction of ciclesonide and des-CIC and determines whether the presence of other agents or disease states affects protein binding. Protein binding of des-CIC (0.5, 5.0, 25, 100, and 500 ng/mL) was determined, using both equilibrium dialysis and ultrafiltration, in plasma from humans (healthy and either renally or hepatically impaired) and several animal species and in the presence of either salicylates or warfarin. Dialyzed samples were analyzed by liquid chromatography with tandem mass spectroscopy to determine both free and bound concentrations of des-CIC. After ultrafiltration, spiked plasma plus H-des-CIC was separated into free and bound fractions by centrifugation and quantified by scintillation counting. Additionally, in another study, protein binding of ciclesonide was determined by equilibrium dialysis. For equilibrium dialysis, the mean percentages of des-CIC (0.5-500 ng/mL) plasma protein binding across species were high, approximately 99%, and no apparent saturation of protein binding was observed. Results were similar for ultrafiltration analysis. Protein binding of des-CIC did not change in the presence of warfarin or salicylates or in the plasma of renally or hepatically impaired patients. The protein binding of ciclesonide was 99.4% in human serum. The very low fraction of unbound des-CIC in the systemic circulation suggests minimal systemic exposure of unbound des-CIC, thus suggesting a low potential for systemic adverse effects after administration of inhaled ciclesonide.

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OBJECTIVE: Inhaled corticosteroids may cause oropharyngeal side effects if deposited in the oropharynx in active form. Ciclesonide, an inhaled corticosteroid with low glucocorticoid receptor affinity, is activated primarily in the lung by esterases to an active metabolite, desisobutyryl-ciclesonide (des-CIC), with high glucocorticoid receptor affinity. We studied oropharyngeal deposition of ciclesonide, des-CIC, and budesonide. METHODS: In an open-label, randomized, two-treatment (administered in sequence), five-period study, 18 healthy subjects received 800 microg (ex-valve) inhaled ciclesonide via a hydrofluoroalkane-pressurized, metered-dose inhaler followed by 800 microg budesonide (Pulmicort) by a chlorofluorocarbon-pressurized, metered-dose inhaler (four puffs of 200 microg each, ex-valve) or vice versa. Oropharyngeal cavity rinsing was performed immediately, or 15, 30, 45, or 60 min after inhalation (one rinsing per study period), and the solutions were analyzed using liquid chromatography with tandem mass spectrometric detection. RESULTS: Ciclesonide and budesonide were detected in most oropharyngeal wash samples. Maximal concentration of each inhaled corticosteroid was reached immediately post-inhalation; maximal concentrations of ciclesonide and des-CIC were 30% and 0.67%, respectively, of budesonide. Oropharyngeal deposition of ciclesonide and budesonide decreased rapidly within 15 min post-inhalation, and less rapidly thereafter. Less than 10% of the residual ciclesonide in the oropharynx was converted to des-CIC. The molar dose-adjusted amount of des-CIC was 4% of budesonide (P < 0.0001). There were no significant adverse events. CONCLUSION: Oropharyngeal deposition of des-CIC was more than one order of magnitude lower than that of budesonide when administered by the respective metered-dose inhalers. This may explain the low frequency of oropharyngeal side effects of ciclesonide in clinical studies.

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Ciclesonide is a novel inhaled corticosteroid that is converted in the lungs to its active metabolite, desisobutyryl-ciclesonide (des-CIC). The aim of this study was to compare the deposition of ciclesonide, as well as its conversion to des-CIC, in the oropharyngeal cavity with fluticasone propionate (FP) following inhalation via hydrofluoroalkane-propelled metered-dose inhalers (HFA-MDIs). Eighteen asthmatics inhaled ciclesonide 800 microg followed by FP 1000 microg or vice versa in an open, randomized, 2-treatment, 2-sequence study design. The oropharynx was washed out immediately and at 15, 30, 45, and 60 minutes after inhalation. Samples were analyzed for ciclesonide, des-CIC, and FP using liquid chromatography with tandem mass-spectrometric detection. Concentration-time curves and area under the concentration-time curve (AUC) were calculated for each drug. Ciclesonide and FP were recovered in almost all samples. Within 60 minutes after inhalation, the amounts of both ciclesonide and FP decreased sharply, and low residual levels were detected after 30 minutes. des-CIC was detected in relatively low concentrations, with maximum concentration 30 minutes following inhalation. The AUC(0-60 min) for ciclesonide (250.4 nmol x h/L) and des-CIC (37.8 nmol x h/L) were found to be significantly lower compared with FP (636.2 nmol.h/L, P < .001). Approximately 50% less ciclesonide and 90% less metabolite were present in the oropharynx compared with FP. Less than 20% of the residual ciclesonide in the oropharynx was metabolized to des-CIC. These findings indicate that oropharyngeal deposition of ciclesonide is only half that of FP following inhalation from an HFA-MDI. Furthermore, there is little activation of ciclesonide to its active metabolite in the oropharynx, suggesting a decreased likelihood of inhaled ciclesonide-associated oropharyngeal side effects.

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BACKGROUND: Ciclesonide is a novel inhaled corticosteroid developed for the treatment of asthma. OBJECTIVE: To investigate the extent of oral absorption and bioavailability of ciclesonide referenced to an intravenous infusion. This information provides an estimate for the contribution of the swallowed fraction to systemic exposure to ciclesonide after oral inhalation. METHODS: In a randomised crossover study, six healthy male subjects (age range 19-40 years) received single doses of 6.9 mg (oral administration) and 0.64 mg (intravenous administration) of [14C]ciclesonide, separated by a washout period of at least 14 days. Total radioactivity was determined in whole blood, plasma, urine and faeces. Serum concentrations of ciclesonide and its major metabolite, the pharmacologically active desisobutyryl-ciclesonide (des-CIC), were determined in serum by high-performance liquid chromatography with tandem mass spectrometry detection. RESULTS: After a 10-minute intravenous infusion, the mean half-life for total radioactivity was 45.2 hours. Elimination of des-CIC was fast with a mean elimination half-life of 3.5 hours. After oral administration, the mean half-life for total radioactivity was 27.5 hours. On the basis of a comparison of dose-normalised areas under the curve of total plasma radioactivity versus time, 24.5% of orally administered [14C]ciclesonide was absorbed. The parent compound ciclesonide was not detected in any of the serum samples after oral administration; serum concentrations of des-CIC were mostly near or below the lower limit of quantification. Thus, systemic bioavailability for des-CIC is <1% and the absolute bioavailability of ciclesonide is even less than this. [14C]Ciclesonide showed no retention in red blood cells. The mean cumulative excretion of total radioactivity was almost complete by 120 hours after oral and intravenous administration. Faecal excretion was the predominant route of excretion for total radioactivity after both routes of administration. Single oral and intravenous administration of ciclesonide was well tolerated. CONCLUSIONS: Because of an almost complete first-pass metabolism, ciclesonide is undetectable in serum after oral administration. Thus, any ciclesonide swallowed after oral inhalation does not contribute to systemically available ciclesonide or to its active metabolite. Drug-related metabolites are excreted mainly via the faeces, and overall recovery of administered radioactivity is virtually complete after an extended sample collection period.

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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.

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