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150 result(s) for "Adrenal Cortex Hormones - pharmacokinetics"
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Population pharmacokinetics and pharmacodynamics of two dosing regimens of antenatal corticosteroids: protocol for a prospective nested study in a randomised controlled trial
IntroductionAntenatal corticosteroid (ACS) regimens have remained unchanged since the initial trials in 1972, with the optimal regimen still undetermined. The WHO ACTION (Antenatal CorticosTeroids for Improving Outcomes in preterm Newborns)-III trial is a three-arm individually randomised double-blind trial evaluating the efficacy and safety of two different ACS dosing regimens (currently used and lower-dose ACS regimens vs placebo) in women with a high probability of having a late preterm birth. This study protocol nested within this trial aims to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) effects of two different ACS dosing regimens in pregnant women in the late preterm period (34–36 weeks) to help inform an optimal dosing regimen.Methods and analysisThe study will be conducted in two of the five countries participating in the WHO ACTION-III trial—India (Delhi, Belagavi) and Nigeria (Ibadan and Ile-Ife). We will use a population PK approach using sparse sampling to study the PK effects of the two ACS regimens, that is, 6 mg dexamethasone phosphate (DEXp) or 2 mg betamethasone phosphate (BETp), administered intramuscularly every 12 hours for a maximum of four doses or till birth, whichever is earlier, compared with placebo. We will also ascertain the fetal–maternal ratio of DEXp and BETp at birth.Maternal venous blood samples will be collected at 0, 1–4 hours, 8–12 hours after the first dose, and at 24–36 hours, 48–60 hours, 72–96 hours after the last dose, and immediately after birth, along with cord blood. Concentrations of DEXp and BETp will be measured at set time points using a validated liquid chromatography mass spectroscopy assay. PD parameters measured will include total and differential white blood cell count (by automated analysers using electrical impedance), plasma glucose (hexokinase method) and serum cortisol (using a validated electrochemiluminescence immunoassay), at predefined time points. PK models will be developed for each drug using non-linear mixed effects methods. Optimal dosing will be investigated using Monte Carlo simulations.Ethics and disseminationThe study has been approved by the WHO Ethics Review Committee and the site-specific ethics committees of the participating leading institutions. Written informed consent will be obtained from all participants. The study results will be published in a peer-reviewed journal and presented at scientific conferences.Trial registration numberISRCTN11434567.
Population pharmacokinetic modeling of intramuscular and oral dexamethasone and betamethasone in Indian women
Population analysis of pharmacokinetic data for five differing dosage forms and routes for dexamethasone and betamethasone in 48 healthy nonpregnant Indian women was performed that accounted for a partial and complex cross-over design. Single doses of 6 mg dexamethasone phosphate (DEX-P), betamethasone phosphate (BET-P), or 1:1 mixture of betamethasone phosphate and acetate (BET-PA) were administered orally (PO) or intramuscularly (IM). Plasma concentrations collected for two periods over 96 h were described with a two-compartment model with differing PO and IM first-order absorption inputs. Clearances and volumes were divided by the IM bioavailability FIM. The homogeneous ages, body weights, and ethnicity of the women obviated covariate analysis. Parameter estimates were obtained by the Laplace estimation method implemented in NONMEM 7.4. Typical values for dexamethasone were clearance (CL/FIM) of 9.29 L/h, steady-state volume (Vss/FIM) of 56.4 L, IM absorption constant kaIM of 0.460 1/h and oral absorption constant (kaPO) of 0.936 1/h. Betamethasone parameters were CL/FIM of 5.95 L/h, Vss/FIM of 72.4 L, kaIM of 0.971 1/h, and kaPO of 1.21 1/h. The PO to IM F values were close to 1.0 for both drugs. The terminal half-lives averaged about 7.5 h for DEX, 17 h for BET, and 78 h for BET from BET-PA with the latter reflecting very slow release of BET from the acetate ester. Overall, BET exhibited slower clearance, larger volume of distribution, faster absorption, and longer persistence than DEX. These data may be useful in considering exposures when substituting one form of corticosteroid for another.
The bioavailability and airway clearance of the steroid component of budesonide/formoterol and salmeterol/fluticasone after inhaled administration in patients with COPD and healthy subjects: a randomized controlled trial
Background Airway absorption and bioavailability of inhaled corticosteroids (ICSs) may0020be influenced by differences in pharmacokinetic properties such as lipophilicity and patient characteristics such as lung function. This study aimed to further investigate and clarify the distribution of budesonide and fluticasone in patients with severe chronic obstructive pulmonary disease (COPD) by measuring the systemic availability and sputum concentration of budesonide and fluticasone, administered via combination inhalers with the respective long-acting β 2 -agonists, formoterol and salmeterol. Methods This was a randomized, double-blind, double-dummy, two-way crossover, multicenter study. Following a run-in period, 28 patients with severe COPD (mean age 65 years, mean forced expiratory volume in 1 second [FEV 1 ] 37.5% predicted normal) and 27 healthy subjects (mean age 31 years, FEV 1 103.3% predicted normal) received two single-dose treatments of budesonide/formoterol (400/12 μg) and salmeterol/fluticasone (50/500 μg), separated by a 4–14-day washout period. ICS concentrations were measured over 10 hours post-inhalation in plasma in all subjects, and over 6 hours in spontaneously expectorated sputum in COPD patients. The primary end point was the area under the curve (AUC) of budesonide and fluticasone plasma concentrations in COPD patients relative to healthy subjects. Results Mean plasma AUC values were lower in COPD patients versus healthy subjects for budesonide (3.07 μM·hr versus 6.21 μM·hr) and fluticasone (0.84 μM·hr versus 1.50 μM·hr), and the dose-adjusted AUC (geometric mean) ratios in healthy subjects and patients with severe COPD for plasma budesonide and fluticasone were similar (2.02 versus 1.80; primary end point). In COPD patients, the T max and the mean residence time in the systemic circulation were shorter for budesonide versus fluticasone (15.5 min versus 50.8 min and 4.41 hrs versus 12.78 hrs, respectively) and C max was higher (1.08 μM versus 0.09 μM). The amount of expectorated fluticasone (percentage of estimated lung-deposited dose) in sputum over 6 hours was significantly higher versus budesonide (ratio 5.21; p = 0.006). Both treatments were well tolerated. Conclusion The relative systemic availabilities of budesonide and fluticasone between patients with severe COPD and healthy subjects were similar. In patients with COPD, a larger fraction of fluticasone was expectorated in the sputum as compared with budesonide. Trial registration Trial registration number NCT00379028
Pharmacokinetics, Safety, and Tolerability of a New Fluticasone Propionate Multidose Dry Powder Inhaler Compared With Fluticasone Propionate Diskus® in Healthy Adults
Abstract 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.
Clinical Efficacy and Tolerability of a Novel Selective Corticosteroid in Atopic Dermatitis - Two Randomised Controlled Trials
Topical corticosteroids remain the first-line therapy for atopic dermatitis (AD). Hence, we investigated the efficacy and safety profile of a novel selective corticosteroid, GW870086. We performed 2 randomised, double-blind, controlled studies with 25 AD patients and 20 healthy subjects. The changes in the Three-Item Severity (TIS) score and the skin thickness were the primary end points, respectively. The adjusted TIS score (day 22) shows that the novel corticosteroid resulted in a non-significant, but dose-dependent reduction compared to placebo (GW870086 0.2% vs. placebo = -0.38, GW870086 2% vs. placebo = -0.89). Significant skin thinning was observed in the second study on days 14 and 21 when patients were treated with the comparator but not with the novel corticosteroid compared to placebo. The clinical efficacy of the new selective corticosteroid was not superior to placebo, although a dose-dependent improvement upon treatment was noticed without the onset of skin thinning.
Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Ulcerative Colitis
Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology, probably caused by a combination of genetic and environmental factors. The treatment of patients with active UC depends on the severity, localization and history of IBD medication. According to the classic step-up approach, treatment with 5-aminosalicylic acid compounds is the first step in the treatment of mild to moderately active UC. Corticosteroids, such as prednisolone are used in UC patients with moderate to severe disease activity, but only for remission induction therapy because of side effects associated with long-term use. Thiopurines are the next step in the treatment of active UC but monotherapy during induction therapy in UC patients is not preferred because of their slow onset. Therapeutic drug monitoring (TDM) of the pharmacologically active metabolites of thiopurines, 6-thioguanine nucleotide (6-TGN), has proven to be beneficial. Thiopurine S-methyltransferase (TMPT) plays a role in the metabolic conversion pathway of thiopurines and exhibits genetic polymorphism; however, the clinical benefit and relevance of TPMT genotyping is not well established. In patients with severely active UC refractory to corticosteroids, calcineurin inhibitors such as ciclosporin A (CsA) and tacrolimus are potential therapeutic options. These agents usually have a rather rapid onset of action. Monoclonal antibodies (anti-tumor necrosis factor [TNF] agents, vedolizumab) are the last pharmacotherapeutic option for UC patients before surgery becomes inevitable. Body weight, albumin status and antidrug antibodies contribute to the variability in the pharmacokinetics of anti-TNF agents. Additionally, the use of concomitant immunomodulators (thiopurines/methotrexate) lowers the rate of immunogenicity, and therefore the concomitant use of anti-TNF therapy with an immunomodulator may confer some advantage compared with monotherapy in certain patients. TDM of anti-TNF agents could be beneficial in patients with primary nonresponse and secondary loss of response. The potential benefit of applying TDM during vedolizumab treatment has yet to be determined.
Quantitative characterization of circadian rhythm of pulmonary function in asthmatic patients treated with inhaled corticosteroids
The aim of this study was to characterize the circadian rhythm observed for forced expiratory volume in 1 s (FEV 1 ) in patients with persistent asthma being treated with inhaled corticosteroids. The database included 3379 FEV 1 measurements from 189 patients with mild to moderate asthma. A model using the sum of two Sine functions with periods of 12 and 24 h and a constant component of mean circadian rhythm adequately described the circadian rhythm in FEV 1 measurements over time. The model adequateness was evaluated by various approaches including visual predictive check (VPC), prediction-corrected VPC, standardized VPC and normalized prediction distribution error. Covariates tested included age, body weight, height, body mass index, baseline FEV 1 , and sex. Age and height were found to have significant effects on the mean FEV 1 level and no covariate was found to have an effect on the magnitude and timing of circadian rhythm. The model predicted that a minimum FEV 1 occurred in the early morning and maximum FEV 1 occurred in the early afternoon, with a population mean fluctuation of 170 mL, which is consistent with the finding that asthma symptoms usually exacerbate in the early morning for patients with persistent asthma. This developed model provides the first quantitative approach to describing FEV 1 circadian rhythm with ICS background treatment and provided insight in designing future registration trials for asthma drug development.
Bioavailability of fluticasone propionate and mometasone furoate aqueous nasal sprays
To compare the systemic exposure for intranasal mometasone furoate (MF) and fluticasone propionate (FP) aqueous nasal sprays (ANS) in terms of serum and urinary cortisol parameters and plasma pharmacokinetics. Twelve healthy subjects completed this three-way, cross-over study. They received FPANS (50 microg/spray), MFANS (50 microg/spray) or placebo ANS, eight sprays per nostril every 8 h for 4 days. Cortisol measurements were made at baseline and day 4. FP and MF plasma concentrations were also measured on day 4. MFANS produced similar mean plasma AUC (123 pmol/l h) to FPANS (112 pmol/l h). Despite the use of high doses, necessary to generate adequate pharmacokinetic data, only minor reductions in cortisol parameters were found, with no difference between FPANS and MFANS. FP and MF have similar and very low systemic bioavailability when administered intranasally using a high-dose regimen. It is therefore unlikely that therapeutic doses of intranasal FP or MF will produce dissimilar or significant degrees of systemic exposure or systemic effects.
Polymer-free corticosteroid dimer implants for controlled and sustained drug delivery
Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients. These implants undergo surface erosion, achieving tightly controlled and reproducible drug release kinetics in vitro. As an example, when used as ocular implants in rats, a dexamethasone dimer implant is shown to effectively inhibit inflammation induced by lipopolysaccharide. In a rabbit model, dexamethasone dimer intravitreal implants demonstrate predictable pharmacokinetics and significantly extend drug release duration and efficacy (>6 months) compared to a leading commercial polymeric dexamethasone-releasing implant. Polymer-based systems are often considered a necessity for controlled drug delivery, but have well-known limitations. Here, the authors report on drug delivery implants formed solely from corticosteroid dimers, which demonstrate controlled release and overcome many of the challenges of polymer-based systems.
Population Pharmacokinetic/Pharmacodynamic Modeling of Systemic Corticosteroid Inhibition of Whole Blood Lymphocytes: Modeling Interoccasion Pharmacodynamic Variability
To develop a population pharmacokinetic/pharmacodynamic (PK/PD) model that characterizes the effects of major systemic corticosteroids on lymphocyte trafficking and responsiveness. Single, presumably equivalent, doses of intravenous hydrocortisone (HC), dexamethasone (DEX), methylprednisolone (MPL), and oral prednisolone (PNL) were administered to five healthy male subjects in a five--way crossover, placebo--controlled study. Measurements included plasma drug and cortisol concentrations, total lymphocyte counts, and whole blood lymphocyte proliferation (WBLP). Population data analysis was performed using a Monte Carlo-Parametric Expectation Maximization algorithm. The final indirect, multi-component, mechanism-based model well captured the circadian rhythm exhibited in cortisol production and suppression, lymphocyte trafficking, and WBLP temporal profiles. In contrast to PK parameters, variability of drug concentrations producing 50% maximal immunosuppression (IC(50)) were larger between subjects (73-118%). The individual log-transformed reciprocal posterior Bayesian estimates of IC(50) for ex vivo WBLP were highly correlated with those determined in vitro for the four drugs (r ( 2 ) = 0.928). The immunosuppressive dynamics of the four corticosteroids was well described by the population PK/PD model with the incorporation of inter-occasion variability for several model components. This study provides improvements in modeling systemic corticosteroid effects and demonstrates greater variability of system and dynamic parameters compared to pharmacokinetics.