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

Optimizing the Delivery of Inhaled Medication for Respiratory Patients: The Role of Valved Holding Chambers

Valved holding chambers (VHCs) have been used with pressurized metered-dose inhalers since the early 1980s. They have been shown to increase fine particle delivery to the lungs, decrease oropharyngeal deposition, and reduce side effects such as throat irritation, dysphonia, and oral candidiasis that are common with use of pressurized metered-dose inhalers (pMDIs) alone. VHCs act as aerosol reservoirs, allowing the user to actuate the pMDI device and then inhale the medication in a two-step process that helps users overcome challenges in coordinating pMDI actuation with inhalation. The design of VHC devices can have an impact on performance. Features such as antistatic properties, effective face-to-facemask seal feedback whistles indicating correct inhalation speed, and inhalation indicators all help improve function and performance, and have been demonstrated to improve asthma control, reduce the rate of exacerbations, and improve quality of life. Not all VHCs are the same, and they are not interchangeable. Each pairing of a pMDI device plus VHC should be considered as a unique delivery system.

Benefits and Risks of Long-Term Asthma Management in Children: Where Are We Heading?

International guidelines provide recommendations for a stepwise approach to the management of asthma in children 0-4 years old, 5-11 years old, and adolescents who are treated as adults. Therapy is aimed at two domains of control: current impairment and future risk. The long-term controller medications, inhaled corticosteroids (ICSs), ICSs in combination with long-acting β₂ agonists, leukotriene receptor antagonists, and immunomodulators, exhibit different efficacies for these domains. The risk:benefit ratios of the available medications need to be carefully assessed. This review briefly presents the benefits and the potential risks of available asthma medications in children to assist the practitioner in the optimal use of asthma medications. Specifically, the systemic activity of the ICSs and how to minimize their effects on growth and adrenal activity are reviewed as well as other potential adverse effects. Dosing strategies such as intermittent therapy are also assessed.

Inhaled corticosteroids: Effects on growth and bone health

BACKGROUND

Both slowed growth in children and reduced bone mineral density (BMD) are systemic effects of corticosteroids, and there is concern about the degree to which these systemic effects affect growth and BMD.

OBJECTIVE

To engage in a data-driven discussion of the effects of inhaled corticosteroids (ICSs) on growth in children and BMD.

METHODS

Articles were selected based on their relevance to this review.

RESULTS

Studies of ICSs in children in which growth was a secondary outcome have revealed slowed growth associated with low doses of budesonide, fluticasone propionate, and beclomethasone dipropionate. In the study of budesonide, the effect was permanent, and in the study of fluticasone propionate, the effect was long-lasting, but it is unclear whether the effect was permanent. However, the results of studies in which growth was the primary outcome were mixed. Slowed growth was detected in a study of beclomethasone dipropionate; however, slowed growth was not detected in a study of ciclesonide or flunisolide. A decrease in BMD acquisition in children was associated with high doses but not low to medium doses of ICSs. In adults, there was a dose-related effect of ICSs on BMD. Both higher daily dose and larger cumulative dose were associated with increased bone density loss.

CONCLUSION

Because of the systemic effects on growth and bone health, children should be monitored for growth using stadiometry every 3 to 6 months and BMD should be monitored yearly in patients being treated with high doses of ICSs.

[Bench-test evaluation of spacer devices for fluticasone delivery to infants]

INTRODUCTION

Use of a spacer device to optimize the delivery of fluticasone to infants with asthma is an important issue and clinicians require guidance around the choice of device. This in vitro study characterizes the particle size and the fluticasone delivery via 9 spacers.

METHODS

We used an in vitro infant nasal cast with two different inspiratory flow rates (50 and 100mL/s). Fluticasone particle size in the aerosol was evaluated by laser diffractometry and tracheal deposition by spectrophotometric assay.

RESULTS

Significant differences in particle size were observed between the 9 spacers (similar D50 but D90 from 5.65±0.65 to 8.80±1.35μm). A 75 % or higher respirable fraction was obtained for only 5 spacers. The 50mL/s flow rate lead to the best drug delivery. At this flow, OptiChamber^® (62±3 %) and Vortex^® (91±8.5 %) had a tracheal deposition over 50 % of the initial dose of fluticasone, although the 7 other spacers exhibited a fluticasone deposition less than 25 %.

DISCUSSION

This study shows a wide variation of drug delivery between the 9 spacers studied. We demonstrate that a low inspiratory flow and a spacer showing antistatic properties facilitate drug delivery.

[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.

Pharmacometric Models for Characterizing the Pharmacokinetics of Orally Inhaled Drugs

During the last decades, the importance of modeling and simulation in clinical drug development, with the goal to qualitatively and quantitatively assess and understand mechanisms of pharmacokinetic processes, has strongly increased. However, this increase could not equally be observed for orally inhaled drugs. The objectives of this review are to understand the reasons for this gap and to demonstrate the opportunities that mathematical modeling of pharmacokinetics of orally inhaled drugs offers. To achieve these objectives, this review (i) discusses pulmonary physiological processes and their impact on the pharmacokinetics after drug inhalation, (ii) provides a comprehensive overview of published pharmacokinetic models, (iii) categorizes these models into physiologically based pharmacokinetic (PBPK) and (clinical data-derived) empirical models, (iv) explores both their (mechanistic) plausibility, and (v) addresses critical aspects of different pharmacometric approaches pertinent for drug inhalation. In summary, pulmonary deposition, dissolution, and absorption are highly complex processes and may represent the major challenge for modeling and simulation of PK after oral drug inhalation. Challenges in relating systemic pharmacokinetics with pulmonary efficacy may be another factor contributing to the limited number of existing pharmacokinetic models for orally inhaled drugs. Investigations comprising in vitro experiments, clinical studies, and more sophisticated mathematical approaches are considered to be necessary for elucidating these highly complex pulmonary processes. With this additional knowledge, the PBPK approach might gain additional attractiveness. Currently, (semi-)mechanistic modeling offers an alternative to generate and investigate hypotheses and to more mechanistically understand the pulmonary and systemic pharmacokinetics after oral drug inhalation including the impact of pulmonary diseases.

Emerging aerosol drug delivery strategies: from bench to clinic

Patients with tracheostomies, those requiring mechanical ventilation, and those too small or compromised for conventional devices, are realizing the benefits of increasingly sophisticated aerosol delivery systems. New medicines and novel aerosol formulations, have enhanced our ability to treat lung disease, and are opening the doors for therapy to treat diseases like diabetes, pulmonary hypertension, and cancer. Progress in the aerosol delivery of drugs has been spurred by the significant benefits, including ease of use, patient comfort, greater selectivity of effect, and the potential to decrease side effects.

Inhaled corticosteroids in children: effects on bone mineral density and growth

Potent, topically active corticosteroids with minimum systemic activity have fewer adverse effects than do systemic corticosteroids, and can control both asthma and allergic rhinitis when given in recommended doses. However, study findings show that children with asthma receiving budesonide and beclometasone dipropionate have decreased linear growth, and that children who receive long-term inhaled corticosteroid therapy for asthma have height deficits 1-2 years after treatment initiation that persist into adulthood. The effects of inhaled corticosteroids on growth seem to be dependent on both dose and duration; the degree of systemic effects is dependent on pharmacokinetic properties (ie, absorption, distribution, and elimination), whereas the effective dose delivered is dependent on the delivery system and potency of the molecule. The effects of corticosteroids on bone mineral density in children seem to be more amenable to intervention; long-term therapy with inhaled corticosteroid therapy is safer than frequent bursts of oral corticosteroids on bone mineral accretion in this regard. Importantly, adequate nutrition (particularly sufficient intake of calcium and vitamin D) should prevent or blunt the effects of corticosteroids on bone mineral density. The potential adverse effects of inhaled corticosteroids need to be weighed against the large and well established benefit of these drugs to control persistent asthma. To minimise any adverse effects, treatment with inhaled corticosteroids should always aim to reach the lowest effective dose that gives the patient good asthma control.