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The potential of micron-sized amorphous mesoporous silica particles as a novel controlled release drug delivery system for pulmonary administration has been investigated. Mesoporous silica formulations were demonstrated to provide a narrower particle size distribution and (spherical) shape uniformity compared to commercial micronized formulations, which is critical for repeatable and targeted aerosol delivery to the lungs. The release profiles of a well-known pulmonary drug loaded into mesoporous particles of different mean particle diameters (2.4, 3.9 and 6.3 µm) were analysed after aerosolization in a modified Andersen Cascade Impactor. Systematic control of the release rate of drug loaded into the particles was demonstrated in simulated lung fluid by variation of the mean particle diameter, as well as an enhanced release compared to a commercial micronized formulation. The mesoporous silica formulations all demonstrated an increased release rate of the loaded drug and moreover, under aerosolization from a commercial, low-cost dry powder inhaler (DPI) device, the formulations showed excellent performance, with low retainment and commercially viable fine particle fractions (FPFs). In addition, the measured median mass aerodynamic diameter (MMAD) of the different formulations (2.8, 4.1 and 6.2 µm) was shown to be tuneable with particle size, which can be helpful for targeting different regions in the lung. Together these results demonstrate that mesoporous silica formulations offer a promising novel alternative to current dry powder formulations for pulmonary drug delivery., Competing Interests: Declaration of competing interest At the time of this work, GAP, AF and GRP were employees of Nanologica AB. ME is a current employee of Iconovo AB. The authors report no other conflicts of interest in this work., (Copyright © 2024. Published by Elsevier B.V.)

Traditionally, developing inhaled drug formulations relied on trial and error, yet recent technological advancements have deepened the understanding of 'inhalation biopharmaceutics' i.e. the processes that occur to influence the rate and extent of drug exposure in the lungs. This knowledge has led to the development of new in vitro models that predict the in vivo behavior of drugs, facilitating the enhancement of existing formulation and the development of novel ones. Our prior research examined how simulated lung fluid (SLF) affects the solubility of inhaled drugs. Building on this, we aimed to explore drug dissolution and permeability in lung mucosa models containing mucus. Thus, the permeation of four active pharmaceutical ingredients (APIs), salbutamol sulphate (SS), tiotropium bromide (TioBr), formoterol fumarate (FF) and budesonide (BUD), was assayed in porcine mucus covered Calu-3 cell layers, cultivated at an air liquid interface (ALI) or submerged in a liquid covered (LC) culture system. Further analysis on BUD and FF involved their transport in a mucus-covered PAMPA system. Finally, their dissolution post-aerosolization from Symbicort® was compared using 'simple' Transwell and complex DissolvIt® apparatuses, alone or in presence of porcine mucus or polymer-lipid mucus simulant. The presence of porcine mucus impacted both permeability and dissolution of inhaled drugs. For instance, permeability of SS was reduced by a factor of ten in the Calu-3 ALI model while the permeability of BUD was reduced by factor of two in LC and ALI setups. The comparison of dissolution methodologies indicated that drug dissolution performance was highly dependent on the setup, observing decreased release efficiency and higher variability in Transwell system compared to DissolvIt®. Overall, results demonstrate that relatively simple methodologies can be used to discriminate between formulations in early phase drug product development. However, for more advanced stages complex methods are required. Crucially, it was clear that the impact of mucus and selection of its composition in in vitro testing of dissolution and permeability should not be neglected when developing drugs and formulations intended for inhalation., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Snezana Radivojev, Lukas Kargl, Joana T. Pinto, Eleonore Fröhlich and Amrit Paudel are employees of the Research Center Pharmaceutical Engineering GmbH, which received funding for their work from Chiesi Farmaceutici. Maria Malmlöf and Per Gerde are employed by Inhalation Sciences AB.]., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: Theophylline is used in the treatment of chronic obstructive pulmonary disease but readily causes symptoms of intoxication and exhibits high risks in elderly patients. However, there have only been a few recent reports on the significance of therapeutic drug monitoring (TDM) implementation, especially in elderly patients. To examine the usefulness of theophylline TDM, we evaluated the current status of prescriptions containing theophylline and its side effects and assessed the influence of aging, sex, drug formulation, and concurrent drugs use on theophylline exposure using data from various nationwide databases and a pharmacokinetic modeling approach., Methods: We utilized sampling data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan. Using the data of patients aged ≥80 years, we conducted an association analysis of theophylline and concurrent drugs. The transition in plasma theophylline concentration levels of elderly patients was estimated based on a previously reported physiological-based pharmacokinetic model., Results: Altogether, 3973 patients using theophylline were registered in our dataset, and about 50% were over 70 years old and used theophylline. Therapeutic drug monitoring implementation was confirmed in only 1.13% of patients. The association analysis confirmed a frequent co-occurrence with allopurinol and famotidine, which increase theophylline exposure, in elderly patients aged ≥80 years. The physiologically based pharmacokinetic model indicated that theophylline trough concentrations were 1.65-fold higher in elderly patients aged 80 years compared to those aged 30 years and 1.35-fold higher in females compared to males., Conclusion: This study effectively combined information on the nationwide health care database and modeling approach, indicating the importance of proactive TDM and dose justification for female and elderly patients., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The application of three-dimensional printing (3DP) in the pharmaceutical industry brings a broad spectrum of benefits to patients by addressing individual needs and improve treatment success. This study investigates the sustained release properties of 3DP tablets containing Theophylline (TPH), which is commonly used to treat respiratory diseases and recently having a comeback due to its potential in the treatment of conditions like Covid-19. Since TPH is a narrow therapeutic window (NTW) drug with serious side effects in the event of overdose, the release properties must be observed particularly closely. We employed a state-of-the-art single screw extrusion 3D printer, which is fed with granules containing the drug. By employing a Taguchi orthogonal array design of experiments (DOE), tablet design parameters and factor related process stability were sought to be evaluated fundamentally. Following this, examinations regarding tailored TPH dosages were undertaken and a relationship between the real printed dose of selected tablet designs and their sustained drug release was established. The release profiles were analyzed using different mathematical model fits and compared in terms of mean dissolution times (MDT). Finally, in-vivo/in-vitro correlation (IVIVC) and physiologically based pharmacokinetic (PBPK) modeling showed that a paradigm patient group could be covered with the dosage forms produced., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Use of propellants with high global warming potential (such as HFA-134a) for pressurised metered-dose inhalers (pMDIs) is being phased down. Switching to dry-powder inhalers may not be clinically feasible for all patients; an alternative is reformulation using propellants with low global warming potential. The combination of beclometasone dipropionate/formoterol fumarate/glycopyrronium bromide (BDP/FF/GB) is available for asthma or chronic obstructive pulmonary disease via pMDI using HFA-134a as propellant. This is being reformulated using the low global warming potential propellant HFA-152a. This manuscript reports three studies comparing BDP/FF/GB pharmacokinetics delivered via pMDI using HFA-152a vs HFA-134a., Methods: The studies were four-way crossover, single-dose, randomised, double-blind, in healthy volunteers. In Studies 1 and 2, subjects inhaled four puffs of BDP/FF/GB (Study 1: 100/6/12.5 μg [medium-strength BDP]; Study 2: 200/6/12.5 μg [high-strength]), ingesting activated charcoal in two of the periods (once per propellant). In Study 3, subjects inhaled medium- and high-strength BDP/FF/GB using a spacer. All three studies compared HFA-152a vs HFA-134a in terms of lung availability and total systemic exposure of beclometasone-17-monopropionate (B17MP; active metabolite of BDP), BDP, formoterol and GB. Bioequivalence was concluded if the 90 % confidence intervals (CIs) of the ratios between formulations of the geometric mean maximum plasma concentration (C max ) and area under the plasma concentration-time curve between time zero and the last quantifiable timepoint (AUC 0-t ) for the analytes were between 80 and 125 %., Results: In Studies 1 and 2, systemic exposure bioequivalence (i.e., comparisons without charcoal block) was demonstrated, except for GB C max in Study 2 (upper 90 % CI 125.11 %). For lung availability (i.e., comparisons with charcoal block), B17MP and formoterol demonstrated bioequivalence in both studies, as did BDP in Study 2; in Study 1, BDP upper CIs were 126.96 % for C max and 127.34 % for AUC 0-t ). In Study 1, GB AUC 0-t lower CI was 74.54 %; in Study 2 upper limits were 135.64 % for C max and 129.12 % for AUC 0-t . In Study 3, the bioequivalence criteria were met for BDP, B17MP and formoterol with both BDP/FF/GB strengths, and were met for GB AUC 0-t , although not for C max . Both formulations were similarly well tolerated in all three studies., Conclusions: Overall, while formal bioequivalence cannot be concluded for all analytes, these data suggest therapeutic equivalence of the new formulation with the existing BDP/FF/GB pMDI formulation, therefore supporting reformulation using a propellant with low global warming potential., Competing Interests: Declaration of competing interest FR, MC, AG, KM, AP and GP are employees of Chiesi, the sponsor of the studies. FV and JK are employees of SGS, the clinical trial site. Both have no conflicts of interest to report., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

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 (R 1 , R 2 , T 1 , T 2 ) 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 R 1 and R 2 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 (AUC inf ) 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 AUC inf . This positive correlation for both FP and SX could potentially assist the batch selection for the PK BE study., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Objectives: Theophylline is a bronchodilator with a narrow therapeutic index and primarily metabolised by cytochrome P450 (CYP) 1A2. Xin-yi-san (XYS) is a herbal formula frequently used to ameliorate nasal inflammation. This study aimed to investigate the effects of XYS and its ingredient, imperatorin, on theophylline pharmacokinetics in rats., Methods: The kinetics of XYS- and imperatorin-mediated inhibition of theophylline oxidation were determined. Pharmacokinetics of theophylline were analysed. Comparisons were made with the CYP1A2 inhibitor, fluvoxamine., Key Findings: XYS extract and its ingredient, imperatorin, non-competitively inhibited theophylline oxidation. Fluvoxamine (50 and 100 mg/kg) and XYS (0.5 and 0.9 g/kg) significantly prolonged the time to reach the maximum plasma concentration (tmax) of theophylline by 3-10 fold. In a dose-dependent manner, XYS and imperatorin (0.1-10 mg/kg) treatments significantly decreased theophylline clearance by 27-33% and 19-56%, respectively. XYS (0.9 g/kg) and imperatorin (10 mg/kg) significantly prolonged theophylline elimination half-life by 29% and 142%, respectively. Compared with the increase (51-112%) in the area under curve (AUC) of theophylline by fluvoxamine, the increase (27-57%) by XYS was moderate., Conclusions: XYS decreased theophylline clearance primarily through imperatorin-suppressed theophylline oxidation. Further human studies are essential for the dose adjustment in the co-medication regimen., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Dry powder inhaler (DPI) is recognized as the first choice for lung diseases' treatment. However, it lacks a universal way for DPI formulation development. Fine lactose is commonly added in DPIs to improve delivery performance; however, the fine ratio-dependent mechanism is unclear. Therefore, the objective of this study is to explore the influence of fine lactose ratio on DPI powder properties and aerodynamic behavior, and the fine lactose ratio-dependent mechanism involved during powder fluidization and lung deposition. Here salbutamol sulfate was used as a model drug, Lactohale® 206 as coarse carrier, and Lactohale® 300 as fine component; the mixtures were prepared at 1% drug content, with fine content up to 20%. It was shown that with the fine addition, flowability of the mixtures was improved, interaction among particles was increased, and the presence of fines could help to improve DPI's aerosolization performance. When the fines added were less than 3%, the "active site" hypothesis played a leading role. When the added fines were over 3% but less than 10%, fluidization enhancement mechanism was more important. After the added fines reaching 10%, aggregate mechanism started to dominate. However, FPF cannot be further increased once the fines reached 20%. Moreover, the correlations between FPF and dynamic powder parameters were verified in ternary mixtures, and cohesion had a greater impact on FPF than that of flowability. In conclusion, adding lactose fines is an effective way to improve lung deposition of DPI, with the concrete mechanism lactose fine ratio dependent.

In the context of streamlining generic approval, this study assessed whether pharmacokinetics (PK) could elucidate the pulmonary fate of orally inhaled drug products (OIDPs). Three fluticasone propionate (FP) dry powder inhaler (DPI) formulations (A-4.5, B-3.8, and C-3.7), differing only in type and composition of lactose fines, exhibited median mass aerodynamic diameter (MMAD) of 4.5 μm (A-4.5), 3.8 μm (B-3.8), and 3.7 μm (C-3.7) and varied in dissolution rates (A-4.5 slower than B-3.8 and C-3.7). In vitro total lung dose (TLD in vitro ) was determined as the average dose passing through three anatomical mouth-throat (MT) models and yielded dose normalization factors (DNF) for each DPI formulation X (DNF x = TLD in vitro,x /TLD in vitro,A-4.5 ). The DNF was 1.00 for A-4.5, 1.32 for B-3.8, and 1.21 for C-3.7. Systemic PK after inhalation of 500 μg FP was assessed in a randomized, double-blind, four-way crossover study in 24 healthy volunteers. Peak concentrations (C max ) of A-4.5 relative to those of B-3.8 or C-3.7 lacked bioequivalence without or with dose normalization. The area under the curve (AUC 0-Inf ) was bio-IN-equivalent before dose normalization and bioequivalent after dose normalization. Thus, PK could detect differences in pulmonary available dose (AUC 0-Inf ) and residence time (dose-normalized C max ). The differences in dose-normalized C max could not be explained by differences in in vitro dissolution. This might suggest that C max differences may indicate differences in regional lung deposition. Overall this study supports the use of PK studies to provide relevant information on the pulmonary performance characteristics (i.e., available dose, residence time, and regional lung deposition).

Both asthma and chronic obstructive pulmonary disease (COPD) are inflammatory chronic respiratory conditions with high rates of morbidity and mortality worldwide. The objectives of this review are to briefly describe the pathophysiology and epidemiology of asthma and COPD, discuss guideline recommendations for uncontrolled disease, and review a new generic option for the treatment of asthma and COPD. Although mild forms of these diseases may be controlled with as-needed pharmacotherapy, uncontrolled or persistent asthma and moderate or severe COPD uncontrolled by bronchodilators with elevated eosinophilia or frequent exacerbations may require intervention with combination therapy with inhaled corticosteroids (ICS) and long-acting beta agonists (LABAs), according to international guidelines. Fixed-dose combinations of ICS/LABA are commonly prescribed for both conditions, with fluticasone propionate (FP) and salmeterol forming a cornerstone of many treatment plans. An oral inhalation powder containing the combination of FP and salmeterol has been available as Advair Diskus® in the United States for almost 20 years, and the first and only substitutable generic version of this product has recently been approved for use: Wixela™ Inhub™. Bioequivalence of Wixela Inhub and Advair Diskus has been established. Furthermore, the Inhub inhaler was shown to be robust and easy to use, suggesting that Wixela Inhub may provide an alternative option to Advair Diskus for patients with asthma or COPD requiring intervention with an ICS/LABA., Competing Interests: In accordance with the disclosure policy and our ethical obligations as researchers, we disclose the following interests fully and have in place an approved plan for managing any potential conflicts arising from these interests: Donald P. Tashkin has been a paid consultant for Innoviva and an advisory board member and paid speaker for AstraZeneca, Boehringer-Ingelheim, Sunovion, and Mylan Inc. Jill A. Ohar has received an investigator-initiated grant from Sunovion and has been a paid consultant for Boehringer-Ingelheim, GlaxoSmithKline, Mylan Inc., Theravance, and Sunovion. Arkady Koltun is a Mylan Inc. employee, stock owner, and shareholder. Richard Allan is a Mylan Pharma UK employee and stock owner. Jonathan K. Ward is a Mylan Pharma UK employee and stock owner., (Copyright © 2021 Donald P. Tashkin et al.)

Medicine regulators require the melting points for crystalline drugs, as they are a test for chemical and physical quality. Many drugs, especially salt-forms, suffer concomitant degradation during melting; thus, it would be useful to know if the endotherm associated with melt degradation may be used for characterising the crystallinity of a powder blend. Therefore, the aim of this study was to investigate whether melt-degradation transitions can detect amorphous content in a blend of crystalline and amorphous salbutamol sulphate. Salbutamol sulphate was rendered amorphous by freeze and spray-drying and blended with crystalline drug, forming standards with a range of amorphous content. Crystalline salbutamol sulphate was observed to have a melt-degradation onset of 198.2±0.2°C, while anhydrous amorphous salbutamol sulphate prepared by either method showed similar glass transition temperatures of 119.4±0.7°C combined. Without the energy barrier provided by the ordered crystal lattice, the degradation endotherm for amorphous salbutamol sulphate occurred 50°C below the melting point, with an onset of 143.6±0.2°C. The enthalpies for this degradation transition showed no significant difference between freeze- and spray-dried samples (p>0.05). Distinct from convention, partial integration of the crystalline melt-degradation endotherm was applied to the region 193-221°C which had no contribution from the degradation of amorphous salbutamol sulphate. The linear correlation of these partial areas with amorphous content, R 2 =0.994, yielded limits of detection and quantification of 0.13% and 0.44% respectively, independent of drying technique. Melt-degradation transitions may be re-purposed for the measurement of amorphous content in powder blends, and they have potential for evaluating disorder more generally.

Background: Patients admitted to the hospital with COPD are commonly managed with inhaled short-acting bronchodilators, sometimes in lieu of the long-acting bronchodilators they take as outpatients. If held on admission, these long-acting inhalers should be re-initiated upon discharge; however, health-care transitions sometimes result in unintentional discontinuation., Research Question: What is the risk of unintentional discontinuation of long-acting muscarinic antagonist (LAMA) and long-acting beta-agonist and inhaled corticosteroid (LABA-ICS) combination medications following hospital discharge in older adults with COPD?, Study Design and Methods: A retrospective cohort study was conducted by using health administrative data from 2004 to 2016 from Ontario, Canada. Adults with COPD aged ≥ 66 years who had filled prescriptions for a LAMA or LABA-ICS continuously for ≥ 1 year were included. Log-binomial regression models were used to determine risk of medication discontinuation following hospitalization in each medication cohort., Results: Of the 27,613 hospitalization discharges included in this study, medications were discontinued 1,466 times. Among 78,953 patients with COPD continuously taking a LAMA or LABA-ICS, those hospitalized had a higher risk of having medications being discontinued than those who remained in the community (adjusted risk ratios of 1.50 [95% CI, 1.34-1.67; P < .001] and 1.62 [95% CI, 1.39, 1.90; P < .001] for LAMA and LABA-ICS, respectively). Crude rates of discontinuation for people taking LAMAs were 5.2% in the hospitalization group and 3.3% in the community group; for people taking LABA-ICS, these rates were 5.5% in the hospitalization group and 3.1% in the community group., Interpretation: In an observational study of highly compliant patients with COPD, hospitalization was associated with an increased risk of long-acting inhaler discontinuation. These Results suggest a likely larger discontinuation problem among less adherent patients and should be confirmed and quantified in a prospective cohort of patients with COPD and average compliance. Quality improvement efforts should focus on safe transitions and patient medication reconciliation following discharge., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Revefenacin inhalation solution is an anticholinergic indicated for the maintenance treatment of patients with chronic obstructive pulmonary disease. Mass balance, pharmacokinetics, and metabolism of revefenacin were evaluated after intravenous and oral administration of [ 14 C]-revefenacin in healthy subjects. Pharmacological activity of the major revefenacin metabolite was also assessed. Adult males ( n = 9) received 20 μg intravenously of approximately 1 μCi [ 14 C]-revefenacin and/or a single 200-μg oral solution of approximately 10 μCi [ 14 C]-revefenacin. Mean recovery of radioactive material was 81.4% after intravenous administration (54.4% in feces; 27.1% in urine) and 92.7% after oral dosing (88.0% in feces, 4.7% in urine). Mean absolute bioavailability of oral revefenacin was low (2.8%). Intact revefenacin accounted for approximately 52.1% and 13.1% of the total radioactivity in plasma after intravenous and oral administration, respectively. Two main circulating metabolites were observed in plasma. After an intravenous dose, a hydrolysis product, THRX-195518 (M2) was observed that circulated in plasma at 14.3% of total radioactivity. After an oral dose, both THRX-195518 and THRX-697795 (M10, N-dealkylation and reduction of the parent compound) were observed at 12.5% of total circulating radioactivity. THRX-195518 was the major metabolite excreted in feces and comprised 18.8% and 9.4% of the administered intravenous and oral dose, respectively. The major metabolic pathway for revefenacin was hydrolysis to THRX-195518. In vitro pharmacological evaluation of THRX-195518 indicated that it had a 10-fold lower binding affinity for the M 3 receptor relative to revefenacin. Receptor occupancy analysis suggested that THRX-195518 has minimal contribution to systemic pharmacology relative to revefenacin after inhaled administration. SIGNIFICANCE STATEMENT: The major metabolic pathway for revefenacin was hydrolysis to the metabolite THRX-195518 (M2), and both revefenacin and THRX-195518 underwent hepatic-biliary and fecal elimination after oral or intravenous administration with negligible renal excretion. Pharmacological evaluation of THRX-195518 indicated that it had a 10-fold lower binding affinity for the M 3 muscarinic receptor relative to revefenacin and that THRX-195518 has minimal contribution to systemic pharmacology after inhaled administration., Competing Interests: All authors had access to the data included in the manuscript. The data sets generated during the current study are not publicly available but can be requested from the corresponding author. D.L.B., S.Y., P.-J.C. are employees of Theravance Biopharma US, Inc. C.N.B. and S.S.H. are former employees of Theravance Biopharma US, Inc. M.T.B. is consultant for and received financial support from Theravance Biopharma US, Inc., (Copyright © 2020 The Author(s).)

Background : Primatene ® MIST CFC, an epinephrine metered-dose inhaler (MDI), was discontinued from the market owing to environmental concerns from its use of chlorofluorocarbon (CFC) propellant. As a result, a new epinephrine MDI was developed using hydrofluoroalkane (HFA) propellant. This article reports the pharmacokinetic (PK) profile of the newly Food and Drug Administration-approved epinephrine HFA MDI. Methods : A randomized, evaluator-blinded, active-controlled, single-dose, two-arm crossover study was conducted to evaluate the PK profile of epinephrine HFA (Primatene ® MIST) and epinephrine CFC (Primatene ® MIST CFC) in 23 healthy volunteers to characterize the epinephrine absorption extent and rate. The study was performed at a high dose of five times the normal dose to obtain measurable plasma epinephrine levels. Plasma epinephrine levels were measured and safety was assessed by adverse events (AEs), vital signs, clinical laboratory tests, and physical examinations. Results : Epinephrine HFA demonstrated a greater systemic drug exposure (greater area under the curve) than that of epinephrine CFC (∼37% higher). The C max occurred at ∼2 minutes and was significantly higher in the epinephrine HFA group (0.18 ng/mL) compared with the CFC version (0.046 ng/mL) at normal dose. Within 20 minutes, both groups demonstrated comparable plasma epinephrine levels. No clinically significant adverse effects were found to be associated with epinephrine HFA, even after an ultrahigh dose (i.e., 10 inhalations). Conclusions: The systemic exposure of epinephrine HFA was found to be higher for the first 20 minutes, and then comparable with epinephrine CFC. Minimal AEs were found in this study despite the very high 1250-2200 μg inhaled doses (i.e., 10 inhalations) used for PK characterization.

Purpose: A combined in vitro - in silico methodology was designed to estimate pharmacokinetics of budesonide delivered via dry powder inhaler., Methods: Particle size distributions from three budesonide DPIs, measured with a Next Generation Impactor and Alberta Idealized Throat, were input into a lung deposition model to predict regional deposition. Subsequent systemic exposure was estimated using a pharmacokinetic model that incorporated Nernst-Brunner dissolution in the conducting airways to predict the net influence of dissolution, mucociliary clearance, and absorption., Results: DPIs demonstrated significant in vitro differences in deposition, resulting in large differences in simulated regional deposition in the central conducting airways and the alveolar region. Similar but low deposition in the small conducting airways was observed with each DPI. Pharmacokinetic predictions showed good agreement with in vivo data from the literature. Peak systemic concentration was tied primarily to the alveolar dose, while the area under the curve was more dependent on the total lung dose. Tracheobronchial deposition was poorly correlated with pharmacokinetic data., Conclusions: Combination of realistic in vitro experiments, lung deposition modeling, and pharmacokinetic modeling was shown to provide reasonable estimation of in vivo systemic exposure from DPIs. Such combined approaches are useful in the development of orally inhaled drug products.

Background: Navafenterol (AZD8871) is an inhaled long-acting dual-pharmacology muscarinic antagonist/β 2 -adrenoceptor agonist (MABA) in development for the treatment of obstructive airways diseases. The safety, tolerability, pharmacodynamics, and pharmacokinetics of navafenterol were investigated in patients with mild asthma., Methods: This was a randomised, single-blind, placebo-controlled, single-ascending-dose study. Patients were randomly assigned to one of two cohorts which evaluated escalating doses of navafenterol (50-2100 μg) in an alternating manner over three treatment periods. The primary pharmacodynamic endpoint was the change from pre-dose baseline in trough forced expiratory volume in 1 s (FEV 1 ) for each treatment period., Results: Sixteen patients were randomised; 15 completed treatment. Data from all 16 patients were analysed. The maximum tolerated dose was not identified, and all doses of navafenterol were well tolerated. The most frequently reported treatment-emergent adverse events (TEAEs) were headache (n = 10, 62.5%) and nasopharyngitis (n = 7, 43.8%). No TEAEs were serious, fatal, or led to discontinuation, and no dose dependency was identified. Navafenterol demonstrated a dose-ordered bronchodilatory response with a rapid onset of action (within 5 min post-dose). Doses ≥200 μg resulted in improvements in trough FEV 1 (mean change from baseline range 0.186-0.463 L) with sustained bronchodilation for 24-36 h. Plasma concentrations increased in a dose-proportional manner, peaking ~ 1 h post-dose, with a derived terminal elimination half-life of 15.96-23.10 h., Conclusions: In this study navafenterol was generally well tolerated with a rapid onset of action which was sustained over 36 h., Trial Registration: ClinicalTrials.gov; No.: NCT02573155.

Background: Navafenterol (AZD8871) is a novel, long-acting, dual-pharmacology (muscarinic receptor antagonist and β 2- adrenoceptor agonist) molecule in development for chronic obstructive pulmonary disease and asthma., Methods: These two phase I, randomised, single-blind, multiple-ascending-dose studies evaluated inhaled navafenterol and placebo (3:1 ratio) in healthy, male, non-Japanese (study A; NCT02814656) and Japanese (study B; NCT03159442) volunteers. In each study, volunteers were dosed in three cohorts, allowing gradual dose escalation from 300 μg to 600 μg to 900 μg. The primary objective was to investigate the safety and tolerability of navafenterol at steady state. Pharmacokinetics were also assessed., Results: Twenty-four volunteers completed each study (navafenterol, n = 6; placebo, n = 2 in each cohort). There were no deaths, serious adverse events (AEs) or treatment-emergent AEs (TEAEs) leading to discontinuation of navafenterol. The most frequent TEAEs were vessel puncture-site bruise (placebo, n = 2; navafenterol 900 μg; n = 3) in study A and diarrhoea (placebo, n = 1; navafenterol 300 μg, n = 2; navafenterol 900 μg, n = 3) in study B. No dose-response relationship was observed for TEAEs. There was a dose-dependent increase in mean heart rate on day 16 in both studies. The pharmacokinetics of navafenterol were similar between non-Japanese and Japanese volunteers., Conclusions: Multiple ascending doses of navafenterol were well-tolerated and the safety and pharmacokinetics of navafenterol were similar in non-Japanese and Japanese volunteers. The findings support navafenterol clinical development., Trial Registration: ClinicalTrials.gov ; Nos.: NCT02814656 and NCT03159442; URL: www.clinicaltrials.gov .

Background: Navafenterol (AZD8871) is a dual-pharmacology muscarinic antagonist β 2- agonist (MABA) molecule in development for the treatment of chronic obstructive pulmonary disease (COPD). The pharmacodynamics, safety and tolerability of single doses of navafenterol were investigated in patients with moderate to severe COPD., Methods: This was a randomized, five-way complete cross-over study. Patients received single doses of navafenterol 400 μg, navafenterol 1800 μg and placebo (all double-blind) and indacaterol 150 μg and tiotropium 18 μg (both open-label active comparators). The primary pharmacodynamic endpoint was change from baseline in trough forced expiratory volume in 1 s (FEV 1 ) on day 2. Safety and tolerability were monitored throughout., Results: Thirty-eight patients were randomized and 28 (73.7%) completed the study. Navafenterol 400 μg and 1800 μg demonstrated statistically significant improvements vs placebo in change from baseline in trough FEV 1 (least squares mean [95% confidence interval]: 0.111 [0.059, 0.163] L and 0.210 [0.156, 0.264] L, respectively, both P < .0001). The changes were significantly greater with navafenterol 1800 μg vs the active comparators (least squares mean treatment difference: 0.065-0.069 L, both P < .05). The frequency of treatment-emergent adverse events was similar for placebo and the active comparators (range 34.4-37.5%), slightly higher for navafenterol 400 μg (52.9%), and lowest for navafenterol 1800 μg (22.6%)., Conclusions: Both doses of navafenterol demonstrated sustained bronchodilation over 24 h. Navafenterol was well tolerated and no safety concerns were raised., Trial Registry: ClinicalTrials.gov ; No.: NCT02573155 ; URL: www.clinicaltrials.gov . Registered 9th October, 2015.

Purpose: Available dry powder inhalers (DPIs) have very poor lung delivery efficiencies in children. The objective of this study was to advance and experimentally test a positive-pressure air-jet DPI for children based on the use of a vertical aerosolization chamber and new patient interfaces that contain a three-dimensional (3D) rod array structure., Methods: Aerosolization performance of different air-jet DPI designs was first evaluated based on a 10 mg powder fill mass of a spray-dried excipient enhanced growth (EEG) formulation. Devices were actuated with positive pressure using flow rate (10-20 L/min) and inhaled volume (750 ml) conditions consistent with a 5-year-old child. Devices with best performance were connected to different mouthpiece designs to determine the effect on aerosolization and tested for aerosol penetration through a realistic pediatric in vitro mouth-throat model., Results: Use of the new vertical aerosolization chamber resulted in high quality aerosol formation. Inclusion of a 3D rod array structure in the mouthpiece further reduced aerosol size by approximately 20% compared to conditions without a rod array, and effectively dissipated the turbulent jet leaving the device. Best case device and mouthpiece combinations produced < 2% mouth-throat depositional loss and > 70% lung delivery efficiency based on loaded dose., Conclusions: In conclusion, use of a 3D rod array in the MP of a positive-pressure air-jet DPI was found to reduce aerosol size by 20%, not significantly increase MP depositional loss, reduce mouth-throat deposition by 6.4-fold and enable lung delivery efficiency as high as 73.4% of loaded dose based on pediatric test conditions.

Doxophylline (DOXO) and theophylline are widely used as bronchodilators for treating asthma and chronic obstructive pulmonary disease, and DOXO has a better safety profile than theophylline. How DOXO's metabolism and disposition affect its antiasthmatic efficacy and safety remains to be explored. In this study, the metabolites of DOXO were characterized. A total of nine metabolites of DOXO were identified in vitro using liver microsomes from human and four other animal species. Among them, six metabolites were reported for the first time. The top three metabolites were theophylline acetaldehyde (M1), theophylline-7-acetic acid (M2), and etophylline (M4). A comparative analysis of DOXO metabolism in human using liver microsomes, S9 fraction, and plasma samples demonstrated the following: 1) The metabolism of DOXO began with a cytochrome P450 (P450)-mediated, rate-limiting step at the C ring and produced M1, the most abundant metabolite in human liver microsomes. However, in human plasma, the M1 production was rather low. 2) M1 was further converted to M2 and M4, the end products of DOXO metabolism in vivo, by non-P450 dismutase in the cytosol. This dismutation process also relied on the ratio of NADP + /NADPH in the cell. These findings for the first time elucidated the metabolic sites and routes of DOXO metabolism in human. SIGNIFICANCE STATEMENT: We systematically characterized doxophylline metabolism using in vitro and in vivo assays. Our findings evolved the understandings of metabolic sites and pathways for methylxanthine derivatives with the aldehyde functional group., (Copyright © 2020 by The American Society for Pharmacology and Experimental Therapeutics.)

Background: Coordination between actuation of a pressurized metered dose inhaler (pMDI) and inhalation is a critical manoeuvre that many patients fail to perform correctly. pMDIs connected to spacers do not require hand-lung coordination. This study evaluated the relative lung and systemic bioavailability and oropharyngeal deposition of salbutamol post-inhalation from Ventolin® Evohaler® (GlaxoSmithKline) either alone following verbal inhaler technique counselling (VC) or connected to a newly improved Able Spacer® (AS)., Methods: In a two-period, randomized crossover study, 16 healthy adults inhaled 2 × 100 µg salbutamol puffs (1 min gap) from Ventolin using VC or AS. Immediately after each puff inhalation, each subject gargled with 20 mL water for oropharyngeal deposition (OD) determination. Urine samples were collected 0.5 h (pre-) and 0.5, 1.0 and 2.0 h post-inhalation. Urine was then pooled 2-24 h post-inhalation. The relative lung bioavailability (0-0.5 h urinary salbutamol excretion - USAL0.5) and systemic bioavailability (0-24 h urinary excretion of salbutamol and its metabolite - USALMET24) were determined. A one week washout separated VC and AS use., Results: The mean (SD) USAL0.5 of VC and AS was 5.36 (4.48) and 12.80 (10.83) µg, respectively. The mean (SD) OD was 11.35 (3.37) and 0.48 (0.30) µg, respectively. VC and AS were significantly different in USAL0.5 and OD (p<0.001). USALMET24 was comparable (p>0.05)., Conclusions: Compared with VC, AS doubled the inhaled salbutamol lung dose and minimised its precipitation in the oral cavity. The results suggest this inhalation aid can add therapeutic and safety benefits particularly in patients with continued pMDI technique issues despite repeated VC., Competing Interests: Declaration of Competing Interest W.G.A. is an Academic Researcher in the inhaled respiratory medicine and inhaler devices areas. He has received unconditional travel grants from Clement Clarke International Limited to present his research work at ATS, BTS, ERS and ISAM conferences. G.A.O. has no conflict of interest to declare. M.S. is the Chief Technology Officer (CTO) at Clement Clarke International Limited, UK., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose: The triple combination therapy budesonide/glycopyrrolate/formoterol fumarate in a metered dose inhaler (BGF MDI), formulated by using innovative co-suspension delivery technology, is a new inhaled corticosteroid/long-acting muscarinic antagonist/long-acting β 2 -agonist fixed-dose combination for the maintenance treatment of COPD. For some patients, the use of an MDI may be optimized with a spacer. This Phase I study assessed the effect of a spacer on lung exposure, total systemic exposure, and safety of BGF MDI 320/36/9.6 μg in healthy subjects., Methods: This randomized, open-label, crossover study assessed the pharmacokinetic and safety profiles of BGF MDI in healthy adult subjects who received a single dose of BGF MDI 320/36/9.6 μg (administered as 2 inhalations with 160/18/4.8 μg per actuation) in 4 regimens: without spacer and no charcoal; with spacer and no charcoal; without spacer and with charcoal; and with spacer and with charcoal. Primary objectives were to assess total systemic exposure (without charcoal) and lung exposure (with charcoal) of budesonide, glycopyrronium, and formoterol administered as BGF MDI with and without a spacer. Safety was also assessed., Findings: In total, 56 subjects were randomized (mean age, 29.9 years; 60.7% male, 17.9% former smokers). For systemic exposure (without charcoal), the spacer/without spacer ratio, expressed as a percentage (intrasubject %CV) of C max and AUC 0-tlast , respectively, was 152.0 (47.5) and 132.8 (43.6) for budesonide, 240.6 (80.2) and 154.7 (73.4) for glycopyrronium, and 165.6 (50.7) and 98.6 (53.8) for formoterol. For lung exposure (with charcoal), the spacer/without spacer ratio percentage (%CV) of C max and AUC 0-tlast , respectively, was 183.6 (65.9) and 198.4 (71.5) for budesonide, 262.0 (91.8) and 373.9 (120.7) for glycopyrronium, and 222.9 (56.3) and 385.2 (147.0) for formoterol. Subjects who were judged to have suboptimal inhalation technique without a spacer (those in the lowest drug exposure quartile based on AUC 0-tlast ) had the greatest increase in both total systemic and lung exposure when a spacer was used versus no spacer. Subjects in the highest quartile had a minimal change in both total systemic and lung exposure when the spacer was used. Treatment-emergent adverse events (TEAEs) (all mild/moderate) reported by >1 subject per regimen were headache, cough, and dizziness. One subject withdrew because of TEAEs of headache and presyncope (neither considered treatment-related)., Implications: Drug delivery can be improved for subjects with suboptimal MDI inhalation technique when using a spacer device with BGF MDI triple therapy. ClinicalTrials.gov identifier: NCT03311373., Competing Interests: Disclosures Dr. Dorinsky and Mr Gillen are employees of AstraZeneca and hold stock and/or stock options in the company. Ms. Trivedi and Dr. Darken are employees of AstraZeneca. Dr. DeAngelis is a former employee of AstraZeneca and holds stock and/or stock options in the company. Dr. DePetrillo is an employee of Pharmaron CPC. Employees of AstraZeneca were involved in various aspects of the conception and design of the studies, acquisition of data, analysis and interpretation of data, and input into manuscript development. The sponsor did not place any restrictions on authors about the statements made in the final article. Data underlying the findings described in this manuscript may be obtained in accordance with AstraZeneca's data sharing policy described at: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Wixela ® Inhub ® is a dry powder inhaler approved as a generic equivalent to Advair ® Diskus ® (fluticasone propionate [FP]/salmeterol fixed-dose combination) for patients with asthma or chronic obstructive pulmonary disease (COPD). This study aimed at confirming the local (lung) therapeutic equivalence of both the FP and salmeterol components of Wixela Inhub (test [T]) to Advair Diskus (reference [R]) after inhalation. Methods: This randomized, double-blind, double-dummy, placebo-controlled, parallel-group study in patients ≥18 years with mild-to-moderate persistent asthma compared the local therapeutic equivalence (using forced expiratory volume in 1 second [FEV 1 ]) of FP/salmeterol (100/50 μg) after inhaled delivery via T and R. Results: Randomized patients ( N  = 1127) received T ( n  = 512), R ( n  = 512), or placebo ( n  = 103). T and R significantly increased day 1 FEV 1 area under the effect curve over 12 hours of the change from baseline (AUC [0-12] ) and day 29 trough FEV 1 over placebo, indicating that these endpoints were sufficiently sensitive for evaluation of bioequivalence. On day 1, T and R each increased FEV 1 AUC (0-12) over placebo (3.134 L•h [T], 2.677 L•h [R]; each p  < 0.0001). Following twice-daily dosing for 28 days, T and R also each increased trough FEV 1 (measured on day 29) over placebo (235 mL [T], 215 mL [R]; each p  < 0.0001). Least-squares mean T/R ratios (90% confidence intervals) for day 1 FEV 1 AUC (0-12) and day 29 trough FEV 1 were 1.120 (1.016-1.237) and 1.069 (0.938-1.220), respectively, indicating that T and R were bioequivalent for both co-primary endpoints. FP/salmeterol was well tolerated when administered via either T or R. Conclusions: These results demonstrate that the therapeutic effects of Wixela Inhub are bioequivalent to Advair Diskus in the lung. Wixela Inhub represents a therapeutically equivalent new FP/salmeterol treatment option for use in the treatment of asthma and COPD.

Epinephrine is the standard of care for the treatment of severe allergy and anaphylaxis. Epinephrine is most often administered through the intramuscular (IM) route via autoinjector. The current study aimed to evaluate an alternative method of epinephrine treatment through intranasal (IN) delivery in dogs. The pharmacokinetic (PK) parameters of maximum plasma concentration (C max ), time to reach maximum plasma concentration (T max ), and area under the plasma concentration-time curve from 0 to 90 minutes (AUC 0-90 ) were observed after IN epinephrine (2, 3, 4, 5, 10, and 20 mg) and IM epinephrine via autoinjector (0.15 and 0.3 mg) for 90 minutes. Heart rate effects were measured after IN (2 and 5 mg) and IM (0.15 and 0.3 mg) epinephrine administration. IN epinephrine (5 mg) demonstrated significantly greater plasma epinephrine concentration at 1 minute as compared with IM epinephrine (0.3 mg) (1.68 ± 0.65 ng/mL vs 0.21 ± 0.08 ng/mL, P = .03). There were no significant differences in C max , T max , and AUC 0-90 between 2-mg IN and 0.15-mg IM epinephrine or between 5-mg IN and 0.3-mg IM epinephrine. IN epinephrine reduced heart rate increases, as compared to IM epinephrine. IN and IM epinephrine were both well-tolerated. Overall, IN epinephrine demonstrated advantages over IM epinephrine, including the rapid increase in plasma epinephrine and lack of increased heart rate over time., (© 2020 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.)

The objective of the present work was to formulate, optimize, and evaluate transdermal terbutaline sulfate (TBN)-loaded bilosomes (BLS) in gel, compared to conventional oral TBN solution and transdermal gel loaded with free TBN, aiming at evading the hepatic first-pass metabolism. A face-centered central composite design was adopted to observe the effects of different formulation variables on TBN-BLS, and artificial neural network (ANN) modeling was employed to optimize TBN-BLS. TBN-BLS were prepared by a thin film hydration method integrating soybean phosphatidylcholine and cholesterol as a lipid phase and sodium deoxycholate (SDC) as a surfactant with or without the coating of chitosan (CTS). After being subjected to physicochemical characterization, TBN-BLS were enrolled in a histopathological study and pharmacokinetic investigation in a rat model. The optimized TBN chitosan-coated bilosomes (TBN-CTS-BLS) were spherical vesicles (245.13 ± 10.23 nm) with adequate entrapment efficiency (65.25 ± 5.51%) and good permeation characteristics (340.11 ± 22.34 μg/cm 2 ). The TBN-CTS-BLS gel formulation was well-tolerated with no inflammatory signs manifested upon histopathological evaluation. The pharmacokinetic study revealed that the optimized TBN-CTS-BLS formulation successively enhanced the bioavailability of TBN by about 2.33-fold and increased t 1/2 to about 6.21 ± 0.24 h as compared to the oral solution. These findings support the prospect use of BLS as active and safe transdermal carrier for TBN in the treatment of asthma. Graphical Abstract.

Background: For the treatment of respiratory disease, inhaled drug delivery aims to provide direct access to pharmacological target sites while minimizing systemic exposure. Despite this long-held tenet of inhaled therapeutic advantage, there are limited data of regional drug localization in the lungs after inhalation. The aim of this study was to investigate the distribution and retention of different chemotypes typifying available inhaled drugs [slowly dissolving neutral fluticasone propionate (FP) and soluble bases salmeterol and salbutamol] using mass spectrometry imaging (MSI). Methods: Salmeterol, salbutamol, and FP were simultaneously delivered by inhaled nebulization to rats. In the same animals, salmeterol- d 3 , salbutamol- d 3 , and FP- d 3 were delivered by intravenous (IV) injection. Samples of lung tissue were obtained at 2- and 30-minute postdosing, and high-resolution MSI was used to study drug distribution and retention. Results: IV delivery resulted in homogeneous lung distribution for all molecules. In comparison, while inhalation also gave rise to drug presence in the entire lung, there were regional chemotype-dependent areas of higher abundance. At the 30-minute time point, inhaled salmeterol and salbutamol were preferentially retained in bronchiolar tissue, whereas FP was retained in all regions of the lungs. Conclusion: This study clearly demonstrates that inhaled small molecule chemotypes are differentially distributed in lung tissue after inhalation, and that high-resolution MSI can be applied to study these retention patterns.

Background: Budesonide/glycopyrrolate/formoterol fumarate metered dose inhaler (BGF MDI), formulated using co-suspension delivery technology, is a triple fixed-dose combination in late-stage clinical development for chronic obstructive pulmonary disease (COPD)., Methods: We conducted two studies to characterize the pharmacokinetic (PK) profile of BGF MDI in patients with COPD: (i) a phase I, open-label, single and chronic (7-day) dosing study (NCT03250182) with one treatment arm (BGF MDI 320/18/9.6 μg); and (ii) a PK sub-study of KRONOS (NCT02497001), a phase III, randomized, double-blind study in which patients received 24 weeks' treatment with BGF MDI 320/18/9.6 μg, glycopyrrolate/formoterol fumarate (GFF) MDI 18/9.6 μg, budesonide/formoterol fumarate (BFF) MDI 320/9.6 μg, or budesonide/formoterol fumarate dry powder inhaler (BUD/FORM DPI) 320/9 μg. PK parameters in both studies included maximum observed plasma concentration (C max ) and area under the plasma concentration-time curve from 0 to 12h (AUC 0-12 )., Results: In the phase I PK study (30 patients), budesonide and glycopyrronium C max were comparable after single and chronic dosing of BGF MDI (accumulation ratio [R AC ] 95% and 107%, respectively) whereas C max for formoterol was slightly higher after chronic dosing (R AC 116%). AUC 0-12 for budesonide, glycopyrronium, and formoterol were higher following chronic versus single dosing, with an R AC of 126%, 179%, and 143%, respectively. After 7 days' dosing, AUC 0-12 and C max for all three components of BGF MDI were similar to those in the KRONOS PK sub-study (202 patients) at Week 24. In the latter sub-study, C max and AUC 0-12  at Week 24 were generally comparable across treatments for budesonide (geometric mean ratios [GMR] of 96%-109% for BGF MDI vs BFF MDI or BUD/FORM DPI), glycopyrronium (GMR of 88%-100% for BGF MDI vs GFF MDI), and formoterol (GMR of 80%-113% for BGF MDI vs GFF MDI or BFF MDI)., Conclusions: Steady-state PK parameters of budesonide, glycopyrronium, and formoterol were similar after 7 days' dosing in the phase I PK study and after 24 weeks in the KRONOS PK sub-study. Systemic exposure to budesonide, glycopyrronium, and formoterol was generally comparable across treatments in the KRONOS PK sub-study, suggesting no meaningful drug-drug or within-formulation PK interactions., (Copyright © 2019 AstraZeneca. Published by Elsevier Ltd.. All rights reserved.)

Background: Wixela ® Inhub ® was developed to deliver inhaled fluticasone propionate/salmeterol (FP/S) combination as a substitutable generic equivalent to Advair ® Diskus ® . These studies aimed to confirm the pharmacokinetic bioequivalence (BE) of FP/S after single doses of Wixela Inhub (test [T]) and Advair Diskus (reference [R]). Methods: Three open-label, randomized, two-way crossover, single-dose studies in healthy subjects ( N  = 66 each) compared the systemic exposure of FP and salmeterol after inhalation from three dose strengths of FP/S (100/50, 250/50, or 500/50 μg) delivered from T and R. Primary BE endpoints were the area under the plasma concentration-time curve from time = 0 to the last measurable concentration (AUC (0-t) ) and the maximum observed plasma concentration (C max ) for both FP and S. The BE acceptance criteria specified that the 90% confidence intervals (CIs) of the geometric mean T/R ratios for AUC (0-t) and C max can be contained within 0.80-1.25 for both FP and salmeterol. Results: Wixela Inhub met the acceptance criteria for BE for FP and salmeterol at each dose strength. Estimated AUC (0-t) and C max geometric mean ratios (T/R [90% CI]) for FP were, respectively, 1.04 (1.00-1.08) and 0.92 (0.87-0.96) for 100/50 μg FP/S, 1.07 (1.02-1.13) and 1.01 (0.95-1.07) for 250/50 μg, and 0.97 (0.92, 1.00) and 0.90 (0.86-0.93) for 500/50 μg. Estimated AUC (0-t) and C max ratios for salmeterol were, respectively, 1.08 (1.04-1.11) and 1.00 (0.94-1.04) for 100/50 μg FP/S, 1.03 (0.99-1.07) and 0.93 (0.87-1.00) for 250/50 μg, and 1.00 (0.96-1.04) and 0.86 (0.81-0.91) for 500/50 μg. FP/S at all doses via both T and R was comparably well tolerated. Conclusions: Wixela Inhub was bioequivalent to Advair Diskus at all three dose strengths for both FP and S, providing direct evidence of equivalent systemic safety and indirect evidence for equivalent pulmonary deposition.

Introduction : There is solid evidence that in patients with poorly controlled severe asthma despite the use of ICS and LABA, the addition of LAMAs, such as tiotropium, significantly increases the time to the first severe exacerbation and provides a modest but sustained bronchodilation. However, only a very limited number of pharmacokinetic studies with these agents have been performed in asthmatic patients. Areas covered : The pharmacokinetic profile of inhaled tiotropium, umeclidinium and glycopyrronium in healthy volunteers and that of inhaled tiotropium and umeclidinium in asthmatic patients have been reviewed. Expert opinion : In asthmatic patients, LAMAs are rapidly absorbed into the systemic compartment and demonstrate bi-exponential elimination (rapidly declining plasma concentrations followed by slow apparent terminal elimination). Apparently, the severity of asthma does not change the pharmacokinetics of LAMAs. The limited information available is focused on the plasma pharmacokinetic profile of these drugs and, consequently, although suitable for establishing a systemic safety profile, it does not tell us much about possible therapeutic efficacy of LAMAs in asthmatics because quantification of systemic plasma values is neither at the airways, which are their site of action nor representative of their transport to this site.

Background: The impact of inhalers' postdispensing, real-life temperature and relative humidity (RH) environments on their delivered dose (DD) and aerodynamic particle size distribution (APSD) is usually overlooked. This work evaluated the salbutamol DD and APSD of Ventolin ® Evohaler ® (V) inhalers already been used and stored by respiratory patients. Methods: Adult patients, prescribed V for ≥3 months before study enrollment, were dispensed both new V to use and portable, handheld electronic temperature and RH data loggers to keep close to the given V before returning them both after 2-3 weeks. Patients' enrollment took place during summer (VS) and winter (VW) seasons. The returned V was then in vitro evaluated using the Next Generation Impactor, and compared with control V (VC) counterparts stored under 21°C and 46% RH. Results: The VS survived in fluctuating habitats of 21.2°C-40.4°C and 16.2%-63.2% RH, which significantly ( p  < 0.05) decreased the salbutamol DD from 80.4 to 70.5 μg compared with VC. This 12.3% DD reduction was accompanied with a decrease in the fine particle dose from 26.2 to 20.4 μg ( p  < 0.05), and an increase in the mass median aerodynamic diameter from 2.3 to 2.5 μm ( p  < 0.05). The VW and VC had equivalent DD and APSD. Conclusion: Patients using V are expected to receive smaller lung doses during the hot summer season compared with intentionally well-kept VC. To have equivalent lung deposition, V users should be advised to retain their inhalers around 20°C with minimal daily environmental fluctuations during summer times.

Background: The majority of current nasal delivery devices, commercialized for children, are developed for adults. Differences in the dose reaching the target are expected due to significant differences between the pediatric and adult nasal airway geometries and their inhalation patterns. This study aims to compare the efficacy of most common nasal drug delivery devices in terms of regional delivery of suspension and solution formulations in pediatric and adult subjects. Methods: Anatomically correct nasal models of 2-, 5-, and 50-year old subjects were developed to evaluate regional nasal delivery of suspensions of fluticasone propionate and fluticasone furoate delivered with Flonase ® and Flonase ® Sensimist™, respectively, and the delivery of an aqueous solution of a model drug, administered with MAD Nasal™. Relevant inhalation patterns were considered for each nasal airway geometry. Controlled administration methods were used, and all contributing parameters, including particle size, velocity, and plume geometry, are reported. Results: Regional deposition patterns resulting from Flonase ® Sensimist™ and Flonase ® were not significantly different in each replica ( p  > 0.05), despite their different plume geometry and droplet size distributions. However, there was a significant difference in deposition of nasal sprays between the pediatric (2- and 5-year old) and adult models ( p  < 0.05), while no statistical differences were found between the two pediatric models ( p  > 0.05). The MAD atomizer resulted in different deposition patterns in all three subjects ( p  < 0.05). Conclusion: Nasal sprays are not adequate delivery devices for pediatric population, due to the narrower nasal passage and greater anterior deposition (∼60%). MAD atomizer resulted in significantly less anterior deposition (∼10%-15%) compared to the nasal pumps, but there was ∼30% run off to the throat. An in vitro platform incorporating anatomically correct nasal geometries and inhalation patterns can guide the development of age-appropriate nasal drug delivery devices.

Background: The development of accurate in vitro-in vivo correlations requires the consideration of a number of factors in vitro , including the emulation of upper airway geometry, inhalation maneuver, inhaler orientation, and environmental conditions. In this study, we examine the effects of inhaler insertion angle and humidity on deposition from a number of marketed inhalers. Methods: Three dry-powder inhalers (DPIs; Pulmicort ® Turbuhaler ® , Budelin ® Novolizer ® , and Easyhaler ® Budesonide) were examined at two insertion angles, one with the inhaler directed toward the back of the oral cavity, the other with the inhaler directed toward the tongue. Three pressurized metered-dose inhalers (pMDIs; QVAR ® , Ventolin ® Evohaler ® , and Flovent ® HFA) were examined considering the joint effects of insertion angle (as above) and relative humidity at low (15%-25%) and high (>95%) conditions. Deposited drug masses in an Alberta Idealized Throat and downstream filter were quantified through ultraviolet spectroscopy. Results and Conclusions: Three of six inhalers showed sensitivity to insertion angle. When directed toward the tongue versus the back of the mouth, the filter dose decreased from 21.9% to 15.6% (percent delivered dose) for Easyhaler Budesonide ( p  < 0.001), from 46.5% to 26.0% for Ventolin Evohaler ( p  < 0.001), and from 56.7% to 35.7% for Flovent HFA ( p  < 0.001) for tests at ambient laboratory humidity. Sensitivity to insertion angle and increases in total lung dose variability may be reduced in future products using larger diameter mouthpieces and smaller particles for DPIs and lower-momentum sprays for pMDIs. Humidity influenced deposition from Ventolin Evohaler and Flovent HFA. When oriented toward the back of the oral cavity, the filter dose decreased from 46.5% to 36.9% for Ventolin Evohaler ( p  = 0.005) and from 56.7% to 44.2% for Flovent HFA ( p  < 0.001) at high humidity relative to low. High humidity may cause a reduction in total in vitro lung doses for some pMDI aerosols.

Objectives: The bronchodilator efficacy of a once-daily fixed-dose combination of tiotropium/formoterol (18/12 µg administered via a dry-powder inhaler, Discair) [TIO/FORM fixed group] vs a single-dose of tiotropium (18 µg) by Handihaler 1 alone [TIO mono group], or combined with formoterol 12 µg twice-daily by Aerolizer 2 [TIO/FORM bid group] was compared in patients with moderate-to-severe stable COPD. Methods: COPD patients were randomized (28 patients/group) to receive TIO/FORM fixed , TIO mono , or TIO/FORM bid . AUC for the changes in FEV 1 and FVC over a 24-h period; bronchodilator response (100 ml improvement in FEV 1 ) in the first 30 min; maximum changes in FEV 1 and FVC; and safety data were recorded. The primary endpoint was to confirm the non-inferiority of TIO/FORM fixed vs TIO/FORM bid in terms of the AUC for the changes in FEV 1 over a 24-h period. Results: Changes in AUC 0-24h for FEV 1 and FVC were similar for TIO/FORM fixed and TIO/FORM bid , and were superior to TIO mono ( p  < 0.001). A positive bronchodilator response at 30 min was demonstrated in 50%, 64%, and 71% of patients in the TIO mono , TIO/FORM bid , and TIO/FORM fixed groups, respectively (NS). Maximum FEV 1 and FVC changes were measured as 0.25/0.41 L, 0.32/0.49 L, and 0.37/0.53 L, for TIO mono , TIO/FORM bid , and TIO/FORM fixed , respectively (FEV 1 : TIO/FORM fixed vs TIO mono , p  = 0.0017 and TIO/FORM fixed vs TIO/FORM bid , p  = 0.4846); no differences were recorded between the combination groups. Conclusions: The 24-h bronchodilator efficacy of TIO/FORM fixed 18/12 µg once-daily by Discair 3 was non-inferior to a combination of tiotropium 18 µg by Handihaler plus formoterol 12 µg twice-daily by Aerolizer, and superior to tiotropium 18 µg monotherapy by Handihaler.

Theophylline is a commonly used bronchodilator drug for treatment of chronic canine bronchitis, but no formulations validated in dogs are currently available. An oral, modified and compounded theophylline product (MCT), which could fulfil this need, is available through a USP-compliant, veterinary compounding pharmacy; however, its pharmacokinetic properties are unknown. The aim of this study was to determine the pharmacokinetics of MCT. Plasma drug concentrations were measured in seven healthy, fed dogs after single doses of intravenous aminophylline (8.6 mg/kg theophylline equivalent) and oral MCT (10 mg/kg). Systemic bioavailability of the MCT was 96.2 ± 32.9%. MCT times to maximum concentration, mean absorption time and terminal half-life were 8.85 ± 3.63, 6.95 ± 3.42, and 8.67 ± 1.62 hr, respectively. Based on simulations of 10 mg/kg and 12-hr dosing, steady-state plasma theophylline concentrations are expected to exceed the minimum therapeutic concentration for 71.7 ± 35.6% of the dosing interval. Overall, the MCT product investigated showed similar pharmacokinetic characteristics compared to previously validated extended-release theophylline products. An oral dose of 10 mg/kg q 12 hr is likely an appropriate dosage to begin therapy; however, therapeutic drug monitoring may be warranted because of inter-individual variation., (© 2019 John Wiley & Sons Ltd.)

Dry powder inhalers have attracted more interest over the years in every aspect related to them. Interestingly, when focusing on the effects of particle morphology of the active or carrier (excipient), it is generally regarded particle size and shape to influence drug availability of aerosolized particles. However, to date, few studies have examined the effect of texture, i.e., roughness, on this relationship. The main objective of the present work is to gain a closer understanding of the influence of carrier morphology on the aerosolization performance of dry powder inhaler formulations. Image analysis and microscopy were used to visualize the aerosolization process. It is considered that the scale of morphological features on the surface of the carrier particles is responsible for the dispersion of the powder formulation, separation of the drug/carrier, and entrainment from a dry powder inhaler. Thus, for this study, the carrier particles of different surface roughness were mixed with micronized salbutamol sulphate. Aerosolization in vitro testing was used to evaluate the performance. The results indicate a connection between the qualitative surface roughness of coarse carriers and aerosolization performance during powder dispersibility. This investigation demonstrated that indeed, powder dispersion, a dynamic process, is influenced by the scale of the carrier morphology.

While studies have demonstrated substantial differences in beta 2 -adrenergic agonist enantiomer pharmacology, enantioselective disposition of long-acting beta 2 -adrenergic ligand racemic (rac)-formoterol in blood is inadequately explored after inhaled therapy given analytical challenges. Furthermore, information on enantioselective disposition and partitioning of beta 2 -adrenergic agonist in skeletal muscle is absent despite its promising data on muscle anabolism in humans. Using a sensitive ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS) assay, we determined disposition of (R,R)-formoterol and (S,S)-formoterol in plasma and skeletal muscle samples from 11 non-asthmatic men who had inhaled rac-formoterol at therapeutic doses (2 × 27 μg). Mean (SD) concentrations of (R,R)- and (S,S)-formoterol in plasma and in muscle biopsies of the vastus lateralis 1 hour after inhalation of formoterol were 31 (15) and 45 (18) pg × mL -1 for (R,R)-formoterol and (S,S)-formoterol, respectively, in plasma, and 0.56 (0.32) and 0.51 (0.29) pg × mg wet wt -1 , respectively, in muscle. Formoterol exhibited different enantioselective disposition in plasma and muscle (p < 0.0001). In plasma, mean log (R,R):(S,S)-formoterol ratio was lower than 0 [-0.17(0.07), p < 0.0001], whereas in muscle, mean log (R,R):(S,S)-formoterol ratio was slightly higher than 0 [0.04(0.07), p < 0.05]. Log (R,R):(S,S)-formoterol ratio in muscle was related to muscle fiber-type composition. Furthermore, formoterol induced an approximately two-fold increase in muscle p-PKA Ser/thr phosphorylation (p < 0.01), indicating a substantial beta 2 -adrenergic response. Collectively, these findings suggest that formoterol exhibits modest enantioselective disposition in plasma after inhaled therapy in humans, which appear related to a greater (R,R)-enantiomer disposition in skeletal muscle that may be dependent on fiber-type composition., (© 2019 John Wiley & Sons, Ltd.)

It is essential to optimize a carrier of dry powder inhalation (DPI) for the aerodynamic deposition in vitro to achieve pulmonary delivery of drug molecules in vivo. In this study, neutralized nanoporous γ-cyclodextrin metal-organic framework (CD-MOF) crystals with cubic morphology and uniform inhalation size were developed and modified as a DPI carrier for budesonide (BUD). Cholesterol (CHO) and leucine (LEU)-poloxamer were used to modify the CD-MOF powder for the improvement of flowability and particle aerodynamic behaviour, for which the particle size distribution, Carr's index and in vitro pulmonary deposition were assessed. Compared to CD-MOF or LEU-CD-MOF-BUD, CHO-CD-MOF had a superior mass median aerodynamic diameter (4.35 ± 0.04 μm) and inhalable performance (fine particle fraction of 30.60 ± 0.76%), which were maintained after budesonide loading (4.47 ± 0.30 μm, 24.95 ± 4.33%). The crystallinity, cytotoxicity and in vivo deposition of drug loaded samples (CHO-CD-MOF-BUD) were then investigated by powder X-ray diffraction (PXRD), cell viability study, in vivo fluorescence imaging and pharmacokinetic studies in rats. The characteristic PXRD crystallinity peaks of budesonide disappeared after being loaded into CHO-CD-MOF, potentially indicating the molecular incorporation of budesonide into the pores of CD-MOF. The cell viability of A549 cell was more than 90% for CHO-CD-MOF-BUD as a result of the good biocompatibility of CD-MOF. When Rhodamine B was carried by the DPI particles, the fluorescence signal at the lung tissue was markedly improved after cholesterol modification compared with CD-MOF, whilst the bioavailability of CHO-CD-MOF-BUD in rat was equivalent with that of the commercial product of Pulmicort Turbuhaler. Therefore, the CD-MOF powders modified by cholesterol can be used as a promising inhalable carrier for pulmonary delivery of drugs with small dose., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The use of inhaled, fixed-dose, long-acting muscarinic antagonists (LAMA) combined with long-acting, beta 2 -adrenergic receptor agonists (LABA) has become a mainstay in the maintenance treatment of chronic obstructive pulmonary disease (COPD). One of the fixed-dose LAMA/LABA combinations is the dry powder inhaler (DPI) of umeclidinium bromide (UMEC) and vilanterol trifenatate (VI) (62.5 µg/25 µg) approved for once-a-day maintenance treatment of COPD. This paper reviews the use of fixed-dose combination LAMA/LABA agents focusing on the UMEC/VI DPI inhaler in the maintenance treatment of COPD. The fixed-dose combination LAMA/LABA inhaler offers a step beyond a single inhaled maintenance agent but is still a single device for the COPD patient having frequent COPD exacerbations and persistent symptoms not well controlled on one agent. Currently available clinical trials suggest that the once-a-day DPI of UMEC/VI is well-tolerated, safe and non-inferior or better than other currently available inhaled fixed-dose LAMA/LABA combinations for COPD., Competing Interests: The authors report no conflicts of interest in this work.

The surface area of the air/liquid interface in the lungs is substantial, so deposited doses of aerosol medicines per interface surface area when administered via the inhalation route is always quite low. However, in most in vitro systems used for dissolution testing of dry powder inhalables, the dose per surface area is generally much higher. The aim of this study was to investigate in one in vitro lung dissolution system, the DissolvIt, the manner in which the deposited dose per test surface area of drug particles influences the simulated dissolution- and absorption rate. Here we used the dissolution test method DissolvIt to investigate the influence on dissolution behavior by varying the deposited surface density of tested drugs. Dry powders of three different active pharmaceutical ingredients with different solubilities were used; salmeterol, budesonide and fluticasone propionate. It was found that by varying the dose density from 0.23 to 29 µg/cm 2 the dissolution- and absorption rate of test particles was affected for all three substances, with decreasing relative dissolution rates above certain dose limits. The effect was much more prominent with the least soluble fluticasone propionate. In contrast, in a real lung it has been shown that a tenfold increase of the even less soluble fluticasone furoate did not affect the pulmonary dissolution- and absorption as measured in the ex vivo isolated perfused rat lung. This indicates that the deposited particle dose on the test surface used must be carefully considered in all in vitro dissolution testing apparatuses used for inhalation drugs, especially when aiming for in vitro-in vivo correlations. Conclusive data show that in the DissolvIt system consistent normalized dissolution- and absorption data can be obtained if the deposition density of test substance are kept below 1 µg/cm 2 and the variability between the initial drug doses is smaller than 10-15% expressed as standard deviation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The present investigation is to study the effect of two different induction ports (IP), i.e., USP IP and USP-modified IP equipped with andersen cascade impactor on in vitro aerodynamic performance along with the impact of USP-modified glass sampling apparatus on delivered dose uniformity of fluticasone propionate (FP) dry powder inhaler (DPI). FP DPI was fabricated by spray drying technique using engineered mannitol microparticles (EMP) with different force controlling agents, i.e., leucine and magnesium stearate. Additionally, commercially available two DPI inhaler devices namely Handihaler® and Breezhaler® were used to aerosolize the FP blends. Spherical smooth surface of EMP showed good powder flow properties and acceptable percentage content uniformity (> 95%). Amounts of FP deposited in cascade assembly using USP-modified IP with the Breezhaler® device was significantly higher (1.32-fold) as compared with the Handihaler® device. Moreover, USP-modified IP showed better deposition as compared with USP IP. Additionally, both inhaler devices showed a satisfactory delivered dose (> 105%) for FP using modified glass sampling apparatus at a flow rate of 60 L/min for 2 s. It was interesting to note that not only formulation properties but also IP geometry and device resistance have significant impact on DPI deposition pattern. This study is a first detailed account of aerodynamic performance of FP using USP-modified IP and USP-modified glass sampling apparatus. Thus, it can be of potential importance for both the academic and industry perspective.

Fluticasone propionate uptake in the presence of a proprietary cell-penetrating peptide (human stimulus factor, [HSF]) based on the N-terminal domain of lactoferrin was studied, alone and in combination with salmeterol, using an air interface Calu-3 epithelial model. The HSF enhanced uptake and transport of fluticasone propionate across the epithelial barrier when alone and in presence of salmeterol. This was attributed to transcellular-mediated uptake. This HSF is a promising peptide for delivery of therapeutics where enhanced epithelial penetrating is required., (Copyright © 2019 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

Background: There has been a growing trend toward delivering aerosolized medications using high-flow nasal cannula (HFNC). In some cases, patients who do not require high-flow oxygen to maintain adequate oxygenation may benefit from aerosol delivery while receiving low-flow oxygen via HFNC. The objective of this study was to quantify and compare the relative pulmonary and systemic delivery of salbutamol, with 2 different nebulizers, in patients with COPD receiving low-flow oxygen therapy through an HFNC., Methods: Subjects were randomized to receive study doses of 5 mg salbutamol nebulized by either a jet nebulizer or a vibrating mesh nebulizer with a T-piece or spacer on days 1, 3, and 5 of admission. Subjects using the large spacer also received 2 puffs (100 μg each) of salbutamol via a pressurized metered-dose-inhaler prior to the nebulizer dose. Urinary salbutamol excretion 30 min post-inhalation and pooled samples of urinary salbutamol excretion up to 24 h post-inhalation were measured. On day 2, ex vivo studies were performed with salbutamol collected on filters placed between the HFNC and nebulizer, with drug eluted from filters and analyzed to determine inhaled dose., Results: Twelve subjects (6 females), age 51.3 ± 11.2 y, were included. The vibrating mesh nebulizer demonstrated higher urinary salbutamol excretion at 30 min and 24 h post-inhalation compared to a jet nebulizer ( P = .001 and P = .02, respectively). No significant difference was found between the T-piece and large-spacer configurations, even though the spacer provided a significantly larger emitted aerosol dose at the opening of the HFNC ( P = .002)., Conclusions: Aerosolized medication could be efficiently combined with low-flow oxygen, via HFNC, in COPD subjects without the need to interrupt the gas supply. The vibrating mesh nebulizer delivered larger doses to subjects compared to the jet nebulizer. However, there was no benefit of using the large spacer with HFNC in low-flow delivery, because the small inner diameter of the HFNC does not allow larger aerosol droplet sizes (preserved by the spacer) to reach the subject., (Copyright © 2019 by Daedalus Enterprises.)

The aim of the present study was to demonstrate the effect of inhalation-flow, inhalation-volume and number of inhalations on aerosol-delivery of inhaled-salbutamol from two different dry powder inhalers (DPIs) in both healthy-subjects and chronic obstructive pulmonary disease (COPD) patients. Relative pulmonary-bioavailability and systemic-bioavailability of inhaled-salbutamol, delivered by Diskus and Aerolizer, was determined in 24-COPD patients and 24-healthy subjects. The healthy-subjects and the COPD-patients participated in the study for 7 days in which they received 4 study doses of 200 μg salbutamol (one slow-inhalation, two slow-inhalations, one fast-inhalation, and two fast-inhalations) in four alternative days with 24 hr washout period after each dose. Two urine-samples were collected from each study subjects. The first was provided 30 min post inhalation (USAL0.5), as an index of relative pulmonary-bioavailability, and the second was pooled to 24 hr post inhalation (USAL24), as an index of systemic-bioavailability. Fast-inhalation resulted in significantly higher USAL0.5 and USAL24 than slow-inhalation (p˂0.05) after one-inhalation in both healthy-subjects and COPD-patients but there was no significant difference between slow and fast-inhalation after two-inhalations. One-inhalation resulted in significantly higher USAL0.5 and USAL24 in healthy-subjects compared to COPD-patient at both slow and fast-inhalation (p˂0.05) except USAL0.5 with Diskus at slow-inhalation there was no significant difference. Also, two-inhalations resulted in significantly higher USAL0.5 and USAL24 compared to one-inhalation at slow-inhalation only (p˂0.05). No significant difference was found between Aerolizer and Diskus except in USAL0.5 of one slow-inhalation in both health-subjects and COPD-patients (p = 0.048 and 0.047, respectively). Device-formula relation is present at low inhalation-flow since Diskus resulted in significantly higher USAL0.5 and USAL24 in healthy-subjects compared to COPD-patient at slow inhalation than Aerolizer. It is essential to inhale-twice and as hard and deep as possible from each dose when using DPI especially with COPD-patients having poor inspiratory efforts such as elderly patients and children.

Aims: Plasma pharmacokinetics permit the assessment of efficacy and safety of inhaled drugs, and possibly their bioequivalence to other inhaled products. Correlating drug product attributes to lung deposited dose is important to achieving equivalence. PUR0200 is a spray-dried formulation of tiotropium that enables more efficient lung delivery than Spiriva ® HandiHaler ® (HH). The ratio of tiotropium lung-to-oral deposition in PUR0200 was varied to investigate the impact of particle size on tiotropium pharmacokinetics, and the contribution of oral absorption to tiotropium exposure was assessed using charcoal block., Methods: A seven-period, single-dose, crossover study was performed in healthy subjects. PUR0200 formulations differing in dose and aerodynamic particle size were administered in five periods and Spiriva HH in two periods. In one period, Spiriva HH gastrointestinal absorption was blocked with oral charcoal. Tiotropium plasma concentrations were assessed over 8 h after inhalation., Results: PUR0200 pharmacokinetics were influenced by aerodynamic particle size and the ratio of lung-to-oral deposition, with impactor sized mass (ISM) correlating most strongly with exposure. Formulation PUR0217a (3 μg tiotropium) lung deposition was similar to Spiriva HH (18 μg) with and without charcoal block, but total PUR0200 exposure was lower without charcoal. The C max and AUC 0-0.5h of Spiriva HH with and without charcoal block were bioequivalent; however, Spiriva HH AUC 0-8h was lower when gastrointestinal absorption was inhibited with oral charcoal administration., Conclusions: Pharmacokinetic bioequivalence indicative of lung deposition and efficacy can be achieved by matching the reference product ISM. Due to reduced oral deposition and more efficient lung delivery, PUR0200 results in a lower AUC 0-t than Spiriva HH due to reduced absorption of drug from the gastrointestinal tract., (© 2018 The British Pharmacological Society.)

Background: Predicting local lung tissue pharmacodynamic (PD) responses of inhaled drugs is a longstanding challenge related to the lack of experimental techniques to determine local free drug concentrations. This has prompted the use of physiologically based pharmacokinetic (PBPK) modeling to potentially predict local concentration and response. A unique opportunity for PBPK model evaluation is provided by the clinical PD data for salbutamol, which in its inhaled dosage form (400 μg), produces a higher bronchodilatory effect than in its oral dosage form (2 mg) despite lower drug concentrations in blood. The present study aimed at evaluating whether inhalation PBPK model predictions of free drug in tissue would be predictive of these observations., Methods: A PBPK model, including 24 airway generations, was parameterized to describe lung, plasma, and epithelial lining fluid concentrations of salbutamol administered intratracheally and intravenously to rats (100 nmol/kg). Plasma and lung tissue concentrations of unbound (R)-salbutamol, the active enantiomer, were predicted with a humanized version of the model and related to effect in terms of forced expiratory volume in 1 second (FEV 1 )., Results: In contrast to oral dosing, the model predicted inhalation to result in spatial heterogeneity in the target site concentrations (subepithelium) with higher free drug concentrations in the lung as compared with the plasma. FEV 1 of inhaled salbutamol was accurately predicted from the PK/PD relationship derived from oral salbutamol and PBPK predictions of free concentration in airway tissue of high resistance (e.g., 6th generation)., Conclusion: An inhalation PBPK-PD model was developed and shown predictive of local pharmacology of inhaled salbutamol, thus conceptually demonstrating the validity of PBPK model predictions of free drug concentrations in lung tissue. This achievement unlocks the power of inhalation PBPK modeling to interrogate local pharmacology and guide optimization and development of inhaled drugs and their formulations.