Effect of AeroChamber Plus™ on the lung and systemic bioavailability of beclometasone dipropionate/formoterol pMDI

The Pharmacokinetics of Inhaled Drugs

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

Bioequivalence of Two Tiotropium Dry Powder Inhalers and the Utility of Realistic Impactor Testing

Introduction: Inhaled antimuscarinics are a cornerstone of the management of chronic obstructive pulmonary disease. This article details a series of five pharmacokinetic (PK) studies comparing a generic tiotropium dry powder inhaler (DPI) to Spiriva HandiHaler, the realistic in vitro methods used to support those studies, and the related in vitro-in vivo correlations (IVIVCs). Methods: All five PK studies were of open-label, single-dose, crossover design with test and reference treatments administered to healthy subjects. Following unexpected results in the first three PK studies, a realistic impactor method was developed comprising an Oropharyngeal Consortium (OPC) mouth-throat and simulated inspiratory profiles in conjunction with a Next Generation Impactor (NGI). Mass fractions and the in vitro whole lung dose were estimated for the test product and Spiriva® HandiHaler® using this method, and IVIVCs derived. Results: Bioequivalence could not be demonstrated for Cmax in the first three PK studies (test/reference ratios ranging from 83.1% to 131.8%), although was observed for AUCt. Reanalysis of the corresponding biobatches with the realistic NGI method revealed in vitro ratios aligned with these PK data (in contrast to the compendial NGI data) and thus inadvertent selection of "mismatched" biobatches. Two further PK studies were undertaken, supported by the realistic NGI method. With the comparison of test and reference products similarly positioned within their respective product performance distributions, bioequivalence was confirmed in both studies. IVIVCs based on mass fractions as per the realistic NGI method were robust and highly predictive of PK outcomes. Conclusions: The test tiotropium DPI and Spiriva HandiHaler were bioequivalent when equitable biobatch comparisons, based on realistic NGI testing, were performed. The observations from this program support the utility of realistic test methods for inhaled product development.

[Small airway: from definition to treatment]

The small airway, present since the origins of humanity and described barely a century ago, has recently been discovered as the anatomical site where inflammation begins in some obstructive lung diseases, such as asthma and Chronic Obstructive Pulmonary Disease (COPD), per se. Small airway dysfuction was identified in up to 91% of asthmatic patients and in a large proportion of COPD patients. In subjects without pathology, small airway represent 98.8% (approximately 4500 ml) of the total lung volume, contributing only between 10-25% of the total lung resistance; however, in subjects with obstruction, it can represent up to 90% of the total resistance. Despite this, its morphological and functional characteristics allow its dysfunction to remain undetected by conventional diagnostic methods, such as spirometry. Hence the importance of this review, which offers an overview of the tools available to assess small airway dysfunction and the possible therapies that act in this silent zone.

The history, current state and perspectives of aerosol therapy

Nebulization is a very effective method of drug administration. This technique has been popular since ancient times when inhalation of plants rich in tropane alkaloids with spasmolytic and analgesic effects was widely used. Undoubtedly, the invention of anasthesia in the 19th century had an influence on the development of this technique. It resulted in the search for devices that facilitated anasthesia such as pulveriser or hydronium. From the second half of the 21st century, when the first DPI and MDI inhalers were launched, the constant development of aerosol therapy has been noticed. This is due to the fact that nebulization, compared with other means of medicinal substance application (such as oral and intravenous routes of administration), is safer and it exhibits a positive dose/efficacy ratio connected to the reduction of the dose. It enables drugs administration through the lung and possesses very fast onset action. Therefore, various drugs prescribed in respiratory diseases (such as corticosteroids, β-agonists, anticholinergics) are present on the market in a form of an aerosol.

Small Airways, Big Problem: Extrafine beclomethasone/formoterol in asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are common chronic respiratory diseases characterized by an inflammatory process that extends from the central to peripheral airways. Conventional pressurized metered-dose inhalers and most dry-powder inhalers emit drug particles too large to target the small airways effectively. Advancements in drug formulation have given rise to a new generation of inhalers that can generate aerosols with extrafine drug particles that leads to more effective aerosol penetration into the lung periphery. An extrafine formulation of inhaled beclomethasone/formoterol (BDP-FF) with enhanced lung deposition is now available. This document reviews the various real-world and controlled studies that have evaluated the efficacy of extrafine BDP-FF in asthma and COPD.

Pharmacokinetics, pharmacodynamics and safety of a novel extrafine BDP/FF/GB combination delivered via metered-dose inhaler in healthy Chinese subjects

BACKGROUND

BDP/FF/GB pMDI is a novel triple fixed-dose combination of extra-fine inhalation aerosol beclomethasone dipropionate (BDP)/formoterol fumarate (FF)/glycopyrronium bromide (GB). Limited data on the pharmacokinetic (PK) and pharmacodynamic (PD) properties of BDP/FF/GB fixed-dose combination in healthy subjects was available.

PURPOSES

This study aimed to evaluate the pharmacokinetics, pharmacodynamics and safety of BDP/FF/GB pMDI in healthy Chinese subjects.

METHODS

This is an open-label, parallel-group, randomized, single and multiple dose study. In the single dose group, subjects received single supra-therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 400/24/50 µg). In the multiple dose group, subjects received therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 200/12/25 µg), twice daily, for 7 consecutive days. Plasma BDP, B17MP, formoterol and GB were determined by a validated ultra performance liquid chromatography method with tandem mass spectrometric detection (UPLC/MS-MS). Heart rate (HR), QTcF, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were evaluated as the surrogate indicators of pharmacodynamic effects.

RESULTS

A total of 24 subjects were randomized and 22 (11 in each group) completed the study. The dose adjusted pharmacokinetic profiles of BDP, beclomethasone-17-monopropionate (B17MP, the most active metabolite of BDP), formoterol and GB were overall similar in therapeutic and supra- therapeutic dose group, showing dose proportional increase of the systemic exposure to BDP, B17MP, formoterol and GB. The pharmacodynamic variables were within the normal range and showed no significant difference between the two groups. All the treatment-emergent adverse events (TEAEs) were mild and no severe TEAE was reported.

CONCLUSIONS

Dose adjusted PK profiles were similar between therapeutic and supra-therapeutic dose for all compounds, nearly dose proportional systemic exposure to B17MP, formoterol and GB after BDP/FF/GB pMDI administration in healthy Chinese subjects. BDP/FF/GB pMDI was safe and well tolerated in healthy Chinese subjects. The PK profiles were comparable to previously published data from Western European healthy Caucasian subjects.

Bioequivalence studies of inhaled indacaterol maleate in healthy Chinese volunteers under gastrointestinal non-blocking or blocking with concomitant charcoal administration

BACKGROUND

Indacaterol is one of the long-acting beta₂-adrenergic agonists, referred as first-line monotherapy for Chronic obstructive pulmonary disease since 2011. Generic products are encouraged to benefit the large COPD patients in China, in which can provide more choices association with reduced cost and improve the quality of patient life.

OBJECTIVE

The three-part study consists of two independent cohorts of thirty-six subjects, aimed to evaluate the bioequivalence (BE) of two indacaterol formulations in gastrointestinal (GI) absorption charcoal-block or non-block conditions. One pilot study performed in six healthy subjects to determine the blocking effect of a new charcoal-based regimen on GI absorption after orally inhalation of indacaterol.

METHODS

Two BE studies were conducted with a randomized, open-label, 2-period crossover design in two independent 36-healthy-subject cohorts, equivalence in systemic and lung deposition was assessed after inhalation of a single dose of 150 μg indacaterol (test or reference formulation) alone or concomitant administration of charcoal. The charcoal-based regimen was improved by optimizing the dose and number of doses, and its blocking efficacy against GI absorption was assessed in a pilot study. Six healthy subjects received 9 g charcoal 10 min before, immediately after and 2 h after indacaterol (3 g/100 ml water × 3 times). Blood collected at predetermined time points up to 72 h. Plasma indacaterol concentrations were determined using HPLC-MS/MS. Pharmacokinetics parameters were calculated with non-compartment analysis. Equivalences were concluded if the 90% confidence interval (CI) for test: reference of C_max and AUC_0-t fell within the limits of 0.8-1.25.

RESULTS

Indacaterol was undetectable in plasma samples in pilot study. The T/R ratio of the geometric mean C_max and AUC_0-t was 109.9% (90% CI, 106.1-113.8%) and 104.8% (90% CI, 101.5-108.1%) for charcoal-block subjects and 105.4% (90% CI, 99.8% ~ 111.3%), and 101.0% (90% CI, 97.7%-104.4%) for non-block subjects. No serious adverse events were reported.

CONCLUSIONS

The results showed that 150 μg indacaterol (+/- 9 g charcoal) was well tolerated in all subjects. The two formulations are bioequivalent in terms of the rate and absorption both in charcoal-block and non-block conditions. The improved charcoal-based regimen demonstrated to be effective and fully blockade of GI absorption of indacaterol.

Evaluation of systemic absorption and bronchodilator effect of glycopyrronium bromide delivered by nebulizer or a dry powder inhaler in subjects with chronic obstructive pulmonary disease

Background

Effective bronchodilator therapy depends upon adequate drug deposition in the lung. COPD patients who are unable to administer medications efficiently with conventional inhalers may benefit from the use of a nebulizer device. The aim of this study was to evaluate the systemic bioavailability and bronchodilator response of glycopyrronium bromide (GLY) administered by a novel nebulizer (eFlow® closed system [CS] vibrating membrane nebulizer) or dry powder inhaler (DPI) in subjects with moderate-to-severe chronic obstructive pulmonary disease (COPD).

Methods

In this randomized, open-label, single-dose, five-way crossover study, subjects received a sequence of either 50 μg GLY delivered by eFlow CS nebulizer (GLY/eFlow) or 63 μg GLY delivered by DPI (GLY/DPI), with and without activated charcoal, followed by intravenous infusion of 50 μg GLY with a washout period of 7 days between doses. Endpoints included plasma pharmacokinetics, safety and efficacy.

Results

The mean (± SD) baseline predicted forced expiratory volume in 1 s (FEV₁) of the 30 subjects who completed the study was 51 ± 15%, with a FEV₁/forced vital capacity ratio of 50 ± 11%. Without charcoal, the absolute systemic bioavailability of GLY/eFlow and GLY/DPI were approximately 15 and 22%, respectively. Changes from baseline in FEV₁ at 60 min post-dose, without administration of charcoal, were 0.180 L and 0.220 L for GLY/eFlow and GLY/DPI, respectively; FEV₁ improvements were similar when charcoal was administered (0.220 L for both GLY/eFlow and GLY/DPI). There were no significant differences in spirometry between the two devices. Fewer subjects administered GLY/eFlow reported adverse events (n = 15) than GLY/DPI (n = 18).

Conclusions

After single doses, GLY/DPI delivered numerically higher peak and steady state levels of drug than did GLY/eFlow. Nebulized GLY produced similar bronchodilation but lower systemic levels of drug than GLY/DPI. Slightly higher number of subjects reported adverse events with GLY/DPI than with GLY/eFlow. Nebulized GLY may offer an effective alternative to patients with COPD not adequately treated with other devices.

Trial registration

NCT02512302 (ClinicalTrials.gov). Registered 28 May 2015.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1113-z) contains supplementary material, which is available to authorized users.

Effect of a spacer on total systemic and lung bioavailability in healthy volunteers and in vitro performance of the Symbicort® (budesonide/formoterol) pressurized metered dose inhaler

INTRODUCTION

Many patients with chronic obstructive pulmonary disease or asthma experience difficulties in coordinating inhalation with pressurized metered-dose inhaler (pMDI) actuation. The use of a spacer device can improve drug delivery in these patients. The aim of this study was to establish the relative bioavailability of single doses of Symbicort^® (budesonide/formoterol) pMDI 160/4.5 μg/actuation (2 actuations) used with and without a spacer device. In addition, an in vitro study was conducted to characterize performance of the inhaler when used in conjunction with a spacer device.

METHODS

A Phase I, randomized, open-label, single-dose, single-center, crossover study in 50 healthy volunteers (NCT02934607) assessed the relative bioavailability of single-dose Symbicort^® pMDI 160/4.5 μg/actuation (2 actuations) with and without a spacer (AeroChamber Plus^® Flow-Vu^®). Inhaled doses were administered without or with activated charcoal (taken orally) to estimate total systemic exposure and exposure through the lung, respectively. The in vitro study characterized the effect of the spacer with respect to delivered dose, fine particle dose, and dose during simulated breathing of budesonide and formoterol.

RESULTS

In terms of total systemic exposure, use of the spacer increased the relative bioavailability determined by AUC_(0-last) and C_max by 68% (spacer:no spacer treatment ratio, 167.9%; 90% CI, 144.1 to 195.6) and 99% (ratio, 198.7%; 90% CI, 164.4 to 240.2) for budesonide, and 77% (ratio, 176.6%; 90% CI, 145.1 to 215.0) and 124% (ratio, 223.6%; 90% CI, 189.9 to 263.3) for formoterol, respectively, compared with pMDI alone. Similarly, the lung exposure of budesonide and formoterol increased (AUC_(0-last) and C_max by 146% [ratio, 246.0%; 90% CI, 200.7 to 301.6] and 127% [ratio, 226.5%; 90% CI, 186.4 to 275.4] for budesonide, and 173% [ratio, 272.8%; 90% CI, 202.5 to 367.4] and 136% [ratio, 236.2%; 90% CI, 192.6 to 289.6] for formoterol, respectively) when the pMDI was administered through the spacer. When assessed by AUC_(0-last) quartile without spacer, subjects in the lowest exposure quartile (indicating poor inhalation technique) with Symbicort^® pMDI 160/4.5 μg/actuation (2 actuations) had markedly increased total systemic and lung exposure when the same dose was administered with the spacer. In contrast, for subjects in the highest exposure quartile with pMDI alone, total systemic and lung exposure of formoterol and budesonide was similar with and without the spacer. In the in vitro study, the fine particle dose (<5 μm) of both budesonide and formoterol from the spacer at delay time (i.e. pause period after actuation) = 0 s (instantaneous) after actuation was similar to the fine particle dose when not using the spacer. The delivered doses of budesonide and formoterol from the spacer were both lower compared with the doses administered without the spacer. There was also a decrease in delivered dose with increasing delay time.

CONCLUSIONS

The clinical study demonstrated that in subjects with poor inhalation technique the use of the AeroChamber Plus^® Flow-Vu^® spacer increased the bioavailability of Symbicort^® pMDI to a level observed in subjects with good inhalation technique without a spacer. The findings from the in vitro study support the fine particle dose characteristics of Symbicort^® pMDI with the AeroChamber Plus^® Flow-Vu^® spacer.

A review of the in vitro and in vivo valved holding chamber (VHC) literature with a focus on the AeroChamber Plus Flow-Vu Anti-static VHC

Valved holding chambers (VHCs) reduce the need for inhalation-actuation coordination with pressurized metered dose inhalers (pMDIs), reduce oropharyngeal drug deposition and may improve lung deposition and clinical outcomes compared to pMDIs used alone. While VHCs are thus widely advocated for use in vulnerable patient groups within clinical and regulatory guidelines, there is less consensus as to whether the performance differences between different VHCs have clinical implications. This review evaluates the VHC literature, in particular the data pertaining to large- versus small-volume chambers, aerosol performance with a VHC adjunct versus a pMDI alone, charge dissipative/conducting versus non-conducting VHCs, and facemasks, to ascertain whether potentially meaningful differences between VHCs exist. Inconsistencies in the literature are examined and explained, and relationships between in vitro and in vivo data are discussed. A particular focus of this review is the AeroChamber Plus® Flow-Vu® Anti-static VHC, the most recent iteration of the AeroChamber VHC family.

New Treatment Option for Chronic Obstructive Pulmonary Disease: Two Long-Acting Bronchodilators in a Single Metered-Dose Inhaler

Combination long-acting inhaled bronchodilators are central to the management of patients with moderate to very severe chronic obstructive pulmonary disease. Glycopyrrolate is a long-acting muscarinic antagonist (LAMA), and formoterol fumarate is a long-acting beta₂ agonist (LABA). In randomized controlled trials, this LAMA/LABA combination in a metered-dose inhaler was shown to be effective in improving pulmonary function and quality of life. Clinicians now have the availability of 3 delivery systems for LAMA/LABA therapy, including metered-dose inhaler, dry-powder inhaler, and Soft Mist inhaler. On the basis of numerous patient factors, such as cognitive ability, manual strength/dexterity, and peak inspiratory flow, clinicians may select the most appropriate inhalation device. For each inhalation device, persistent patient education is absolutely essential, including observation of patient use. International evidence-based guidelines stress the critical importance of ensuring correct use of inhalation devices.

Dilemmas, Confusion, and Misconceptions Related to Small Airways Directed Therapy

During the past decade, there has been increasing evidence that the small airways (ie, airways < 2 mm in internal diameter) contribute substantially to the pathophysiologic and clinical expression of asthma and COPD. The increased interest in small airways is, at least in part, a result of innovation in small-particle aerosol formulations that better target the distal lung and also advanced physiologic methods of assessing small airway responses. Increasing the precision of drug deposition may improve targeting of specific diseases or receptor locations, decrease airway drug exposure and adverse effects, and thereby increase the efficiency and effectiveness of inhaled drug delivery. The availability of small-particle aerosols of corticosteroids, bronchodilators, or their combination enables a higher total lung deposition and better peripheral lung penetration and provides added clinical benefit, compared with large-particle aerosol treatment. However, a number of questions remain unanswered about the pragmatic approach relevant for clinicians to consider the role of small airways directed therapy in the day-to-day management of asthma and COPD. We thus have tried to clarify the dilemmas, confusion, and misconceptions related to small airways directed therapy. To this end, we have reviewed all studies on small-particle aerosol therapy systematically to address the dilemmas, confusion, and misconceptions related to small airways directed therapy.

[Critical evaluation of inhalation spacer devices available in France]

OBJECTIVE

To identify the spacer devices sold in France and to provide a critical evaluation in the light of the published data.

MATERIALS AND METHODS

We contacted the pharmaceutical companies, manufacturers and distributors of each spacer in order to obtain their technical parameters and the results of any in vitro or in vivo studies. A review of the literature via PubMed completed the first set of data. We were interested in the quantity of fine particles (less than 5 μm diameter) obtained with a cascade impactor at paediatric flow rates, for all inhaled drugs available in France.

RESULTS

Eleven spacer devices were available in 2013 in France (Ablespacer®, Aerochamber Plus®, Babyhaler®, VHC Arrow®, L'Espace®, Funhaler®, Inhaler®, Itinhaler®, OptiChamber Diamond®, Tipshaler® and Vortex®), but three are no longer manufactured (Babyhaler®, Funhaler® and Inhaler®). All were small volume spacers, sold with facial masks of several different sizes. Four were antistatic (Aerochamber Plus®, Intinhaler®, OptiChamber Diamond® and Vortex®). Only salbutamol was tested with all the devices. Inhaled corticosteroids were tested with some and combinations were studied only with Ablespacer®, Aerochamber Plus®, Itinhaler®, and Vortex®. The results were difficult to interpret because the studies were conducted with very different protocols. The only clinical studies were conducted with Aerochamber Plus®, L'Espace® and Vortex®.

CONCLUSION

There was a great disparity between commercialized spacer devices in terms of the available data describing their in vitro performance.

Pharmacokinetics and pharmacodynamics of an extrafine fixed pMDI combination of beclometasone dipropionate/formoterol fumarate in adolescent asthma

AIM

The aim was to investigate the pharmacokinetics and pharmacodynamics of an extrafine pressurized metered-dose inhaler (pMDI) fixed combination of beclometasone dipropionate (BDP)/formoterol fumarate (FF) in adolescent and adult asthma.

METHODS

This was a three-way crossover study, on 30 asthmatic adolescents receiving BDP/FF pMDI with or without a valved holding chamber (VHC) or a free licenced combination of BDP pMDI and FF pMDI plus a parallel arm of 30 asthmatic adults receiving BDP/FF pMDI. All patients received a single dose of BDP and FF of 400 µg and 24 µg, for each treatment, respectively. Assessments were performed over 8 hours.

RESULTS

In adolescents, the 90% confidence intervals (CIs) for the systemic exposure (AUC(0,t)) geometric mean ratio of the fixed combination with or without VHC vs. the free combination were within the bioequivalence range 0.80-1.25, both for beclometasone-17-monopropionate (B17MP, the active metabolite of BDP) and formoterol. Pharmacodynamic variables for plasma potassium and glucose, pulse rate and pulmonary function in adolescents were equivalent between treatments, 95% CI within 0.9, 1.09. The upper level of 90% CIs for AUC(0,t) geometric mean ratio adolescents : adults of B17MP and formoterol after treatment with BDP/FF pMDI was lower than 1.25, 90% CI 0.78, 1.04 and 0.86, 1.17, respectively.

CONCLUSIONS

In adolescents the pharmacodynamics and the overall systemic exposure to the active ingredients of an extrafine fixed combination of BDP/FF pMDI with or without a VHC was equivalent to that of a free licenced combination of pMDIs of established safety and efficacy profiles. The systemic exposure in adolescents was not higher than in adults. These results support the indication for use of inhaled corticosteroid/long acting β2 -adrenoceptor agonist pMDIs in adolescents at the same dosage as in adults.

The systemic exposure to inhaled beclometasone/formoterol pMDI with valved holding chamber is independent of age and body size

BACKGROUND

Asthma guidelines recommend prescription of inhaled corticosteroids at a reduced dosage in children compared to older patients in order to minimize the systemic exposure and risk of unwanted side effects. In children, pressurized metered dose inhalers (pMDI) are recommended in combination with a valved holding chamber (VHC) to overcome the problem of coordinating inhalation with actuation. However, the influence of age and body size on the systemic exposure of drugs to be administered via a pMDI with VHC is still not fully elucidated. Therefore, we aimed to compare the systemic exposure to the active ingredients of a fixed combination of beclometasone-dipropionate/formoterol-fumarate administered via pMDI with VHC in children, adolescents and adults.

METHODS

The pharmacokinetics of formoterol and beclometasone-17-monopropionate (active metabolite of beclometasone-dipropionate) was evaluated over 8 h from three studies, each performed in a different age and body size group. Children (7-11 years, n = 20), adolescents (12-17 years, n = 29) and adults (≥18 years, n = 24) received a single dose of beclometasone/formoterol (children: 200 μg/24 μg, adolescents and adults: 400 μg/24 μg) via pMDI with AeroChamber Plus™.

RESULTS

The systemic exposure in children in comparison to adolescents was equivalent for formoterol while it was halved for beclometasone-17-monopropionate in accordance with the halved dose of beclometasone administered in children (90% CIs within 0.8-1.25 for formoterol and 0.4-0.625 for beclometasone-17-monopropionate). The systemic exposure to beclometasone-17-monopropionate and formoterol was equivalent between adolescents and adults.

CONCLUSIONS

The systemic exposure to the active ingredients of a fixed dose combination of beclometasone/formoterol administered via pMDI with AeroChamber Plus™ correlates with the nominal dose independently of patient age and body size. Thus, dose reduction in relation to age when using a pMDI with VHC may be unnecessary for reducing the systemic exposure in children.

Generics, chemisimilars and biosimilars: is clinical testing fit for purpose?

The effectiveness and safety of generic drugs are backed by sound physicochemical control and regulatory bioequivalence acceptance criteria. Statistical testing of bioequivalence, comparing the pharmacokinetic profiles of the test and reference products, was made possible by modern drug assays. When the pharmacokinetic profile correlates with the dose, such comparisons show assay sensitivity and readily detect differences in dose. For large biological molecules, different manufactured batches cannot be validated using pharmacokinetic data alone. For these biosimilars, there is a three-stage assessment of pharmaceutical quality, laboratory testing and clinical data. This approach has also been applied to certain chemical products, termed 'chemisimilars', which have variable or complex synthesis of the active substance, or complex formulation, or a complex delivery device. Although there may be no detectable difference between the test and reference on clinical testing, many of the outcome measures are insensitive to even large differences in dose. For testing to be fit for purpose it should distinguish important dose differences, but many clinical tests of chemisimilars and biosimilars do not. As pharmacokinetic and pharmacodynamic technology advances, the trend of replacing dose-insensitive clinical trial data with equivalence tests that show assay sensitivity can be expected to continue.

Lung imaging - two dimensional gamma scintigraphy, SPECT, CT and PET

This review will cover the principles of imaging the deposition of inhaled drugs and some of the state-of-the art imaging techniques being used today. Aerosol deposition can be imaged and quantified by the addition of a radiolabel to the aerosol formulation. The subsequent imaging of the inhaled deposition pattern can be acquired by different imaging techniques. Specifically, this review will focus on the use of two-dimensional planar, gamma scintigraphy, SPECT, CT and PET. This review will look at how these imaging techniques are used to investigate the mechanisms of drug delivery in the lung and how the lung anatomy and physiology have the potential to alter therapeutic outcomes.