Distribution of technetium-99m-labelled QVAR delivered using an Autohaler device in children

Measurements of deposited aerosol dose in infants and small children

Pediatric patients are very dependent on inhaled aerosol medications. There are significant differences in how these aerosols deposit in the lungs of children vs. adults that may affect the efficacy of the therapies. Inefficient aerosol delivery to children, caused by factors such as high mouth and throat deposition during oral inhalation, significant losses within adjunct devices such as masks, and high rates of nasal deposition during cannula delivery, can lead to dosing that is difficult to control. Here we discuss the methods, such as deposition scintigraphy, that are used to assess inhaled dose in vivo and review previous studies where these techniques have been applied to measure dosing in children. This includes studies of nebulizers and metered dose inhalers and delivery through adjuncts such as facemasks and nasal cannulas. We discuss the factors that can lead to inefficient inhaled drug delivery and high levels of mouth and throat deposition in children. Finally, we propose areas of innovation to improve inhaled drug delivery to this population. There is a need for child-specific technologies for inhaled drug delivery. This includes the use of smart devices that can guide pediatric breathing patterns and better engage children during treatments, the use of smaller aerosols which are less likely to deposit in the upper airways after inhalation, and the design of better nasal cannula interfaces for aerosol delivery to infants.

Comparison of pulmonary deposition of nebulized 99m technetium-diethylenetriamine-pentaacetic acid through 3 inhalation devices in healthy dogs

Background

Inhalation treatment frequently is used in dogs and cats with chronic respiratory disease. Little is known however about the performance of delivery devices and the distribution of aerosolized drugs in the lower airways.

Objective

To assess the performance of 3 delivery devices and the impact of variable durations of inhalation on the pulmonary and extrapulmonary deposition of nebulized ^99mtechnetium‐diethylenetriamine‐pentaacetic acid (^99mTc‐DTPA).

Animals

Ten university‐owned healthy Beagle dogs.

Methods

Prospective crossover study. Dogs inhaled the radiopharmaceutical for 5 minutes either through the Aerodawg spacer with a custom‐made nose‐muzzle mask, the Aerochamber spacer with the same mask, or the Aerodawg spacer with its original nose mask. In addition, dogs inhaled for 1 and 3 minutes through the second device. Images were obtained by 2‐dimensional planar scintigraphy. Radiopharmaceutical uptake was calculated as an absolute value and as a fraction of the registered dose in the whole body.

Results

Mean (±SD) lung deposition for the 3 devices was 9.2% (±5.0), 11.4% (±4.9), and 9.3% (±4.6), respectively. Differences were not statistically significant. Uptake in pulmonary and extrapulmonary tissues was significantly lower after 1‐minute nebulization, but the mean pulmonary/extrapulmonary deposition ratio (0.38 ± 0.27) was significantly higher than after 5‐minute nebulization (0.16 ± 0.1; P = .03). No significant differences were detected after 3‐ and 5‐minute nebulization.

Conclusion and Clinical Importance

The performance of a pediatric spacer with a custom‐made mask is comparable to that of a veterinary device. One‐minute nebulization provides lower pulmonary uptake but achieves a better pulmonary/extrapulmonary deposition ratio than does 5‐minute nebulization.

In vitro-in vivo correlations (IVIVCs) of deposition for drugs given by oral inhalation

Conventional in vitro tests to assess the aerodynamic particle size distribution (APSD) from inhaler devices use simple right-angle inlets ("mouth-throats", MTs) to cascade impactors, and air is drawn through the system at a fixed flow for a fixed time. Since this arrangement differs substantially from both human oropharyngeal airway anatomy and the patterns of air flow when patients use inhalers, the ability of in vitro tests to predict in vivo deposition of pharmaceutical aerosols has been limited. MTs that mimic the human anatomy, coupled with simulated breathing patterns, have yielded estimates of lung dose from in vitro data that closely match those from in vivo gamma scintigraphic or pharmacokinetic studies. However, different models of MTs do not always yield identical data, and selection of an anatomical MT and representative inhalation profiles remains challenging. Improved in vitro - in vivo correlations (IVIVCs) for inhaled drug products could permit increased reliance on in vitro data when developing new inhaled drug products, and could ultimately result in accelerated drug product development, together with reduced research and development spending.

Effects of Inhaled Corticosteroids and Particle Size on Risk of Obstructive Sleep Apnea: A Large Retrospective Cohort Study

Background: Inhaled corticosteroids (ICS) produce local effects on upper airway dilators that could increase the risk of developing obstructive sleep apnea (OSA). Given that the particle size of ICS changes their distribution, the particle size of ICS may impact the risk of developing OSA. Objectives: In this large retrospective study, we explore the relationship of ICS use and OSA in patients with asthma. In addition, we seek to determine if this relationship is affected by the particle size of ICS. Methods: Using electronic health records, we established a cohort of 29,816 asthmatics aged 12 and older with a diagnosis of asthma documented by ICD-9 or ICD-10 codes between January 2011 and August 2016. We performed analyses of variance and multivariate logistic regression analysis to determine the effects ICS on the diagnosis of OSA with sub-analysis by particle size of ICS. Results: Uncontrolled asthmatics showed increased odds of receiving a diagnosis of OSA whether when looking at ACT scores (adjusted odds ratio (aOR) 1.60, 95% CI 1.32–1.94) or PFT results (aOR 1.45, 95% CI 1.19–1.77). Users of ICS also had increased odds of OSA independent of asthma control (aOR 1.58, 95% CI 1.47–1.70). Notably, users of extra-fine particle ICS did not have significantly increased odds of having OSA compared to non-users of ICS (aOR 1.11, 95% CI 0.78–1.58). Conclusions: Use of ICS appears to be an independent risk factor for OSA. Notably, extra-fine particle size ICS do not appear to be associated with an increased risk of OSA.

Pulmonary deposition of fluticasone propionate/formoterol in healthy volunteers, asthmatics and COPD patients with a novel breath-triggered inhaler

INTRODUCTION

A combination of fluticasone propionate/formoterol fumarate (FP/FORM) has been incorporated within a novel, breath-triggered device, named K-haler^®. This low resistance device requires a gentle inspiratory effort to actuate it, triggering at an inspiratory flow rate of approximately 30 L/min; thus avoiding the need for coordination of inhalation with manual canister depression. The aim of the study was to evaluate total and regional pulmonary deposition of FP/FORM when administered via the K-haler device.

MATERIALS AND METHODS

Twelve healthy subjects, 12 asthmatics, and 12 COPD patients each received a single dose of 2 puffs ^99mtechnetium-labelled FP/FORM 125/5 μg. A gamma camera was used to obtain anterior and posterior two-dimensional images of drug deposition. Prior transmission scans (using a^99mtechnetium flood source) allowed the definition of regions of interest and calculation of attenuation correction factors. Image analysis was performed per standardised methods.

RESULTS

Of 36 subjects, 35 provided evaluable post-dose scintigraphic data. Mean subject ages were 35.7 (healthy), 44.5 (asthma) and 61.7 years (COPD); mean FEV₁% predicted values were 109.8%, 77.4% and 43.2%, respectively. Mean pulmonary deposition was 26.6% (healthy), 44.7% (asthma), 39.0% (COPD) of the delivered dose. The respective mean penetration indices (peripheral:central ratio normalised to a transmission lung scan) were 0.44, 0.31 and 0.30.

CONCLUSION

FP/FORM administration via the K-haler device resulted in high lung deposition in patients with obstructive lung disease but somewhat lesser deposition in healthy subjects. Regional deposition data demonstrated drug deposition in both the central and peripheral regions in all subject populations.

EUDRACT NUMBER

2015-000744-42.

Short-Term Growth During Treatment with Inhaled Fluticasone Propionate/Formoterol, Fluticasone and Beclomethasone Treatment

BACKGROUND

Fluticasone propionate/formoterol (FP/FORM) is a pressurized metered-dose inhaler (pMDI; Flutiform^®) approved for use in adolescents and adults and under development for pediatric use.

OBJECTIVE

To compare short-term growth in asthmatic children treated with FP/FORM, FP pMDI with valved holding chamber, and beclomethasone dipropionate (BDP) in a breath-actuated device.

METHODS

Children with persistent asthma (n = 48; 5 to <12 years) participated in an assessor-blinded, randomized, three-way crossover trial with run in, wash out, and active treatment periods, each of 2 weeks duration. Interventions were FP/FORM 100/10 μg b.i.d. with an AeroChamber Plus^® Flow-Vu^® Spacer, FP pMDI (Flixotide^®) 100 μg b.i.d. with a Volumatic^® spacer, and extra-fine BDP breath-actuated inhaler (Aerobec^®/QVAR^® Autohaler^®) 100 μg b.i.d. Lower leg growth rate (LLGR) was measured by knemometry.

RESULTS

The least square (LS) mean difference in LLGR between FP/FORM and FP (per protocol population) was -0.006 mm/week (95% CI: -0.095 to 0.084; p < 0.001 for noninferiority [noninferiority margin -0.200 mm/week]). Both treatments elicited no change from baseline off-treatment growth rate. The LS mean treatment difference of FP/FORM versus BDP was 0.116 mm/week (95% CI: -0.004 to 0.235; p = 0.057) and of FP versus BDP 0.163 mm/week (95% CI: 0.078-0.249; p < 0.001). Results in the full analysis population were: FP/FORM versus FP -0.012 mm/week (95% CI: -0.080-0.056; p < 0.001); FP/FORM versus BDP 0.143 mm/week (95% CI: 0.064-0.222; p < 0.001); FP versus BDP 0.163 mm/week (95% CI: 0.093-0.233; p < 0.001).

CONCLUSIONS

FP/FORM pMDI with AeroChamber and FP pMDI with Volumatic spacer did not affect lower leg growth, measured by knemometry, in asthmatic children. Conversely, extra-fine BDP from a breath-actuated inhaler resulted in short-term growth suppression.

Inhaled hydrofluoalkane-beclomethasone dipropionate in bronchopulmonary dysplasia. A double-blind, randomized, controlled pilot study

OBJECTIVE

The efficacy of inhaled steroids in spontaneously breathing infants with established bronchopulmonary dysplasia (BPD) is debatable. The inhaled steroid hydrofluoalkane-beclomethasone dipropionate (QVAR) is unique in its small particle size that results in higher lung deposition. Our objective was to determine if inhaled QVAR could decrease respiratory rehospitalizations of infants with established BPD.

STUDY DESIGN

Double-blind, randomized placebo-controlled, multicenter pilot study. Preterm infants with moderate-to-severe BPD were randomized to inhaled QVAR 100 μg per dose or placebo twice daily via Aerochamber with face mask. Treatment was administered daily from recruitment at 36 weeks post menstrual age until 3 months post discharge. Analysis was carried out by intention to treat.

RESULTS

The QVAR (n=18) and placebo (n=20) groups were comparable in birth and recruitment characteristics. Length of stay (108.5±26.3 vs 108.7±36.0 days) and infants requiring oxygen at discharge (5/17 vs 6/19) or at study end (0/17 vs 2/19) were comparable. Respiratory rehospitalizations/infant (0.1±0.5 vs 0.4±0.6), rehospitalization days (0.5±1.5 vs 4.1±10.3), and post-discharge additive inhaled (0.3±0.9 vs 6.4±21.5 days), systemic (0.7±2.8 vs 1.0±1.4 days) and combined (inhaled/systemic) steroids (1.0±2.9 vs 7.8±25.8 days) tended to be lower in the QVAR compared with the placebo group. Blood pressure, height and weight gain, and urine cortisol/creatinine ratio at study end were comparable between groups.

CONCLUSIONS

Our study was unable to detect a significant effect of inhaled QVAR on the respiratory course of established BPD. The study was underpowered. Possible benefits of QVAR could be masked by a tendency toward higher use of additional steroids in the placebo group.

Inhalation Aspects of Therapeutic Aerosols

The pulmonary route of drug delivery can provide an excellent alternative to other routes both for local lung disease as well as systemic delivery. The year 2006 marks the 50th year since the invention of metered dose inhalers, yet inhalation is a very much underutilized route of delivery, possibly because inhalation drug development is perceived as being too difficult and expensive. However with proper knowledge these purported difficulties can be overcome. The process begins with identifying the target tissue and then utilizing technologies such as particle size adjustments through formulation techniques and delivery devices to most efficiently deliver the desired dose. There are a variety of new and existing inhaled excipients available to accomplish this goal. The active molecule can also be modified to increase solubility, decrease immunogenicity, and protect it from unwanted metabolism using PEGylation. Sustained release of an inhaled drug is also possible using biocompatible matrices such as oligolactic acid.

Inhalation devices: from basic science to practical use, innovative vs generic products

INTRODUCTION

Inhalation therapy is a convenient method of treating respiratory diseases. The key factors required for inhalation are the preparation of drug carriers (aerosol particles) allowing reproducible dosing during administration. These technical challenges are accomplished with a variety of inhalation devices (inhalers) and medicinal formulations, which are optimized to be easily converted into inhalable aerosols. Areas covered: This review is focused on the most important, but often overlooked, effects, which are required for the reliable and reproducible inhalable drug administration. The effects of patient-related issues that influence inhalation therapy, such as proper selection of inhalers for specific cases is discussed. We also discuss factors that are the most essential if generic inhalation product should be considered equivalent to the drugs with the clinically confirmed efficacy. Expert opinion: Proper device selection is crucial in clinical results of inhalation therapy. The patients' ability to coordinate inhalation with actuation, generation of optimal flow through the device, use of optimal inspiratory volume, all produces crucial effects on disease control. Also the severity of the disease process effects proper use of inhalers. Interchanging of inhalers can produce potentially conflicting problem regarding efficacy and safety of inhalation therapy.

Extra-fine particle inhaled corticosteroids, pharma-cokinetics and systemic activity in children with asthma

During recent years, extra-fine particle inhaled corticosteroids with a median aerodynamic diameter ≤2 μm have been introduced in the treatment of asthma. The aim of this paper was to review pharmacokinetics and systemic activity of extra-fine particle hydroalkane pressurized metered dose inhaled (pMDI) ciclesonide and beclomethasone dipropionate in children. A literature review was performed. Systemic bioavailability of oral and pulmonary deposition of extra-fine ciclesonide and beclomethasone dipropionate was 52% and 82%, the half-life in serum 3.2 and 1.5 h and first-pass hepatic metabolism >99% and 60%, respectively. Secondary analyses of urine cortisol/creatinine excretion found no effects of ciclesonide pMDI between 40 and 320 μg/day or of beclomethasone dipropionate pMDI between 80 and 400 μg/day. Ciclesonide pMDI 40, 80 and 160 μg/day caused no effects on short-term lower leg growth rate as assessed by knemometry. Ciclesonide 320 μg/day was associated with a numerically short-term growth suppression equivalent to 30% which was similar to 25% and 36% suppression caused by beclomethasone dipropionate HFA and CFC 200 μg/day, respectively. Consistent with the differences in key pharmacokinetic features, beclomethasone dipropionate is associated with a systemic activity detected by knemometry at a lower dose than ciclesonide. Whether that correlates with a clinically important difference remains to be explored. Assessments of systemic activity of beclomethasone dipropionate <200 μg/day and of ciclesonide >180 μg/day as well as head-to-head comparisons are warranted. Preferably, such studies should apply the sensitive method of knemometry.

The effect of body posture during medication inhalation on exercise induced bronchoconstriction in asthmatic children

RATIONALE

Inhaling medication in a standard body posture leads to impaction of particles in the sharp angle of the upper airway. Stretching the upper airway by extending the neck in a forward leaning body posture may improve pulmonary deposition. A single dose of inhaled corticosteroids (ICS) offers acute, but moderate protection against exercise induced bronchoconstriction (EIB). This study investigated whether inhaling a single dose of ICS in a forward leaning posture improves this protection against EIB.

METHODS

32 Asthmatic children, 5-16 years, with EIB (Median fall in FEV1 or FEV0.5 30.9%) performed two exercise challenge tests (ECT's) with spirometry in a single blinded cross-over trial design. Children inhaled a single dose of 200 μg beclomethasone dipropionate (BDP) 4 h before the ECT, once in the standard posture and once with the neck extended in a forward leaning posture. Spirometry was also performed before the inhalation of the single dose of BDP.

RESULTS

Inhalation of BDP in both body postures provided similar protection against EIB (fall in FEV1 or FEV0.1 in standard posture 16.7%; in forward leaning posture 15.1%, p = 0.83). Inhaling ICS in a forward leaning posture significantly delayed EIB compared to inhaling in the standard posture (respectively 2.5 min ± 1.0 min vs. 1.6 min ± 0.8 min; difference 0.9 min (95CI 0.25; 1.44 min); p = 0.01).

CONCLUSION

Inhalation of a single dose BDP in both the forward leaning posture and the standard posture provided effective and similar protection against EIB in asthmatic children, but the forward leaning posture resulted in a delay of EIB.

REGISTER

NTR3432 (www.trialregister.nl).

Reversibility of pulmonary function after inhaling salbutamol in different doses and body postures in asthmatic children

RATIONALE

Pulmonary medication is often delivered in the form of medical aerosols designed for inhalation. Recently, breath actuated inhalers (BAI's) gained popularity as they can be used without spacers. A major drawback of BAI's is the impaction in the upper airway. Stretching the upper airway by a forward leaning body posture with the neck extended ("sniffing position") during inhalation may reduce upper airway impaction and improve pulmonary deposition. Aim of this study was to investigate the reversibility of lung function with different doses salbutamol inhaled with a BAI in the forward leaning posture compared to the standard posture in asthmatic children.

METHODS

22 clinically stable asthmatic children, 5-14 years old, performed four reversibility measurements. Children inhaled 200 μg or 400 μg salbutamol with a BAI in the standard or in the forward leaning posture with the neck extended in a randomized single-blinded cross-over design.

RESULTS

Reversibility of lung function after inhaling salbutamol in the forward leaning posture was not significantly different compared to inhalation in the standard posture. Mean FEV1 reversibility was significantly greater after inhaling 400 μg salbutamol compared to 200 μg salbutamol in the standard posture (9.4% ± 9.5% versus 4.5% ± 7.5%, difference 4.9% (95CI 0.9; 9.0%); p = 0.021).

CONCLUSION

In clinically stable asthmatic children, inhalation of salbutamol with a BAI in a forward leaning posture does not increase reversibility of lung function. Inhalation of 400 μg compared to 200 μg salbutamol with a BAI does improve reversibility.

Small-particle Inhaled Corticosteroid as First-line or Step-up Controller Therapy in Childhood Asthma

BACKGROUND

Because randomized controlled trials of established pediatric asthma therapies are expensive and difficult to perform, observational studies may fill gaps in the evidence base.

OBJECTIVES

To compare the effectiveness of representative small-particle inhaled corticosteroid (ICS) with that of standard size-particle ICS for children initiating or stepping up ICS therapy for asthma (analysis 1) and to compare the effectiveness of ICS dose step-up using small-particle ICS with adding long-acting β2-agonist (LABA) to the ICS (analysis 2).

METHODS

These historical matched cohort analyses drew on electronic medical records of children with asthma aged 5 to 11 years. Variables measured during 2 consecutive years (1 baseline year for confounder definition and 1 outcome year) included risk-domain asthma control (no hospital attendance for asthma, acute oral corticosteroids, or lower respiratory tract infection requiring antibiotics) and rate of severe exacerbations (asthma-related emergency, hospitalization, or oral corticosteroids).

RESULTS

In the initiation population (n = 797 in each cohort), children prescribed small-particle ICS versus standard size-particle ICS experienced greater odds of asthma control (adjusted odds ratio, 1.49; 95% CI, 1.10-2.02) and lower severe exacerbation rate (adjusted rate ratio, 0.56; 95% CI, 0.35-0.88). Step-up outcomes (n = 206 in each cohort) were also significantly better for small-particle ICS, with asthma control adjusted odds ratio of 2.22 (95% CI, 1.23-4.03) and exacerbations adjusted rate ratio of 0.49 (95% CI, 0.27-0.89). The number needed to treat with small-particle ICS to achieve 1 additional child with asthma control was 17 (95% CI, 9-107) for the initiation population and 5 (95% CI, 3-78) for the step-up population. Outcomes were not significantly different for stepped-up small-particle ICS dose versus ICS/LABA combination (n = 185 in each cohort).

CONCLUSIONS

Initiating or stepping up the ICS dose with small-particle ICS rather than with standard size-particle ICS is more effective and shows similar effectiveness to add-on LABA in childhood asthma.

In vitro characterization of the OptiChamber Diamond valved holding chamber

BACKGROUND

Use of a valved holding chamber (VHC) in conjunction with a pressurized metered dose inhaler (pMDI) can reduce issues relating to poor actuation-inhalation coordination and potentially improve the lung deposition of aerosol, compared with use of a pMDI alone. However, the performance of a VHC is influenced by different device-related factors, including the size and shape of the VHC and the material it is manufactured from (conventional versus antistatic). This study aimed to provide an in vitro characterization of an antistatic VHC, the OptiChamber Diamond VHC, comparing the aerodynamic particle size distribution of aerosol delivered via this VHC with results from a second antistatic VHC and a conventional VHC.

METHODS

The pMDI drug formulations (albuterol, suspension; beclomethasone dipropionate, solution) were connected to a Next Generation Impactor, either directly (pMDI alone tests) or via a VHC (VHC tests). The pMDIs were actuated (×10 per product pair) and tested at extraction flow rates of 15 L/min and 30 L/min, without any time delay between actuation and inhalation. Dose delivery using the two pMDI drug formulations was compared, and is presented with reference to key aerodynamic particle size parameters.

RESULTS

Compared with tests on pMDIs alone, use of a VHC increased the dose of aerosol within the respirable range, particularly at a 15 L/min flow rate. Between-VHC comparisons indicated that the two antistatic VHCs were equivalent. Delivery of albuterol appeared to be influenced by the VHC used, but beclomethasone dipropionate seemed unaffected.

CONCLUSIONS

The two antistatic VHCs were equivalent for both pMDI brands. Aerosol delivered from the antistatic VHCs at 15 L/min had a higher proportion of fine particles compared with the conventional VHC.

Pediatric in vitro and in silico models of deposition via oral and nasal inhalation

Respiratory tract deposition models provide a useful method for optimizing the design and administration of inhaled pharmaceutical aerosols, and can be useful for estimating exposure risks to inhaled particulate matter. As aerosol must first pass through the extrathoracic region prior to reaching the lungs, deposition in this region plays an important role in both cases. Compared to adults, much less extrathoracic deposition data are available with pediatric subjects. Recently, progress in magnetic resonance imaging and computed tomography scans to develop pediatric extrathoracic airway replicas has facilitated addressing this issue. Indeed, the use of realistic replicas for benchtop inhaler testing is now relatively common during the development and in vitro evaluation of pediatric respiratory drug delivery devices. Recently, in vitro empirical modeling studies using a moderate number of these realistic replicas have related airway geometry, particle size, fluid properties, and flow rate to extrathoracic deposition. Idealized geometries provide a standardized platform for inhaler testing and exposure risk assessment and have been designed to mimic average in vitro deposition in infants and children by replicating representative average geometrical dimensions. In silico mathematical models have used morphometric data and aerosol physics to illustrate the relative importance of different deposition mechanisms on respiratory tract deposition. Computational fluid dynamics simulations allow for the quantification of local deposition patterns and an in-depth examination of aerosol behavior in the respiratory tract. Recent studies have used both in vitro and in silico deposition measurements in realistic pediatric airway geometries to some success. This article reviews the current understanding of pediatric in vitro and in silico deposition modeling via oral and nasal inhalation.

Reversibility after inhaling salbutamol in different body postures in asthmatic children: a pilot study

RATIONALE

Pulmonary medication is mostly delivered in the form of medical aerosols to minimize systemic side effects. A major drawback of inhaled medication is that the majority of inhaled particles impacts in the oropharynx at the sharp bend of the airway. Stretching the airway by a forward leaning body posture with the neck extended ("sniffing position") may improve pulmonary deposition and clinical effects.

METHODS

41 asthmatic children who were planned for standard reversibility testing at the pulmonary function lab, alternately inhaled 200 μgr salbutamol with an Autohaler(®) in the standard or in the forward leaning body posture. Forced Expiratory Volume in 1 s (FEV1), Forced Vital Capacity (FVC), Peak Expiratory Flow (PEF), Mean Expiratory Flow at 25% of vital capacity (MEF25) and Mean Expiratory Flow at 75% of vital capacity (MEF75) were analysed.

RESULTS

The children in the forward leaning body posture group showed a significantly higher mean FEV1 reversibility than the control group after inhalation of 200 μgr salbutamol (10.2% versus 4.1%, p = 0.019). Additionally, mean MEF75 was significantly more reversible in the forward leaning body posture group versus the standard body posture group (32.2% resp. 8.9%, p = 0.013).

CONCLUSION

This pilot study showed a higher reversibility of FEV1 and MEF75 after inhaling salbutamol in a forward leaning body posture compared to the standard body posture in asthmatic children. This suggests that pulmonary effects of salbutamol can be improved by inhaling in a forward leaning body posture with the neck extended. This effect is possibly due to a higher pulmonary deposition of salbutamol and should be confirmed in a randomized controlled trial.

How to match the optimal currently available inhaler device to an individual child with asthma or recurrent wheeze

Inhaled medications are the cornerstone of treatment in early childhood wheezing and paediatric asthma. A match between patient and device and a correct inhalation technique are crucial for good asthma control. The aim of this paper is to propose an inhaler strategy that will facilitate an inhaler choice most likely to benefit different groups of children. The main focus will be on pressurised metered dose inhalers and dry powder inhalers. In this paper we will discuss (1) practical difficulties with the devices and with inhaled therapy and (2) the optimal location for deposition of medicines in the lungs, and (3) we will propose a practical and easy way to make the best match between the inhaler device and the individual patient. We hope that this paper will contribute to an increased likelihood of treatment success and improved adherence to therapy.

Delivery of inhalation drugs to children for asthma and other respiratory diseases

Infants and children constitute a patient group that has unique requirements in pulmonary drug delivery. Since their lungs develop continuously until they reach adulthood, the airways undergo changes in dimensions and number. Computational models have been devised on the growth dynamics of the airways during childhood, as well as the particle deposition mechanisms in these growing lungs. The models indicate that total aerosol deposition in the body decreases with age, while deposition in the lungs increases with age. This has been observed on paediatric subjects in in vivo studies. Issues unique to children in pulmonary drug delivery include their lower tidal volume, highly variable breathing patterns, air leaks from facemasks, and the off-label or unlicensed use of pharmaceutical products due to lack of clinical data for this age group. The aerosol devices used are essentially those developed for adult patients that have been adapted to paediatric use. Facemasks should be used with nebulisers and spacers for infants and young children. An idealised throat that mimic the average particle deposition in paediatric throats has been designed to obtain more clinically relevant aerosol dispersion data in vitro. More effort should be spent on studying particle deposition in the paediatric lung and developing products specific for this subpopulation to meet their needs.

Comparison of in vitro deposition of pharmaceutical aerosols in an idealized child throat with in vivo deposition in the upper respiratory tract of children

PURPOSE

Deposition of drug emitted from two commercially available inhalers was measured in an in vitro child oral airway model and compared to existing in vivo data to examine the ability of the child model to replicate in vivo deposition.

METHODS

In vitro deposition of drug from a QVAR® pressurized metered dose inhaler (pMDI) and Pulmicort® Turbuhaler® dry powder inhaler (DPI) in an Idealized Child Throat (1) and downstream filter was measured using UV spectroscopy and simulated realistic breathing profiles. Potential effects of ambient relative humidity ranging from 10% to 90% on deposition were also considered.

RESULTS

In vitro QVAR pMDI deposition in the idealized mouth-throat at 50% RH (39.2 ± 2.3% of delivered dose) compared well (p>0.05) with in vivo extrathoracic deposition in asthmatic children age 8 to 14 (45.8 ± 12.3%). In vitro Turbuhaler DPI deposition in the idealized mouth-throat at 50% RH (69.0 ± 1.5%) matched in vivo extrathoracic deposition (p>0.05) in 6 to 16 year old children with cystic fibrosis (70.4 ± 21.2%). The effects of ambient humidity were found to be insignificant for Turbuhaler and minor for QVAR.

CONCLUSIONS

The Idealized Child Throat successfully mimics in vivo deposition data in school age children for the inhalers tested, and may provide a standard platform for optimizing pediatric treatment with inhaled pharmaceutical aerosols.

Use of breath-actuated inhalers in patients with asthma and COPD - an advance in inhalational therapy: a systematic review

The pressurized metered dose inhalers and dry powder inhalers are the most widely used devices for inhalation therapy in asthma and chronic obstructive pulmonary disease; each of these devices have certain advantages and disadvantages that impact their use. Motivation from the virtues of these devices led to the development of breath-actuated or breath-activated metered dose inhalers. A history of the breath-actuated inhalers, the development and technical aspects, studies about the usability, inhalation technique and patient preference, lung deposition and impact on lung function are presented in this review article. This review presents the use of breath-actuated inhalers in asthma and chronic obstructive pulmonary disease and in children and elderly; and a brief economic evaluation aims to put the clinical efficacy and ease-of-use of the breath-actuated inhaler into perspective by understanding the long-term cost benefits associated with this device.

[Inhaled medication in pediatrics]

Three different devices are available for inhaled medications in children: the pressurized metered dose inhalers (pMDIs, breath-actuator synchronized pMDI, and valved holding spacers), the dry powder inhalers, and the nebulizers. To choose the better device for a particular patient, a perfect knowledge of the available devices, of their mode of use, of their advantages and inconvenient is required. The use of a pMDI coupled to a valved holding spacer is the first mode of delivery to propose in children aged less than 6 years. After 6 years old, the DPIs may be proposed depending on the child's competences. At last, the nebulizations are indicated in some particular and severe indications, but new indications are appearing because of recent progresses.

Inhaler devices for patients with COPD

Chronic obstructive pulmonary disease (COPD) continues to be associated with increased morbidity and mortality risk in spite of updated guidelines and a better understanding of this condition. Progressive airflow limitation and resultant hyperinflation-the respiratory hallmarks of this complex and often under-diagnosed disease-can be treated with pharmacotherapies emitted via nebulizers, pressurized metered-dose inhalers, dry powder inhalers, or a Soft Mist inhaler. Pharmaceutical company proprietary issues, technological innovations, and societal pressure have expanded the list of available inhalers, with a limited range of medications available for any one device. Each device has different operating and maintenance instructions, and successful use of a given drug/device combination requires that patients understand, maintain, and use each of their devices properly in order to ensure consistent and optimal pulmonary drug delivery. Clinicians are faced with a range of physical and psychosocial issues unique to each patient with COPD that must be overcome in order to match a suitable inhaler to the individual. Improved drug delivery afforded by next-generation inhalers, coupled with an awareness of device-specific and patient-specific variables affecting inhaler use, may improve clinical outcomes in the treatment of COPD.

Inhaler competence in asthma: common errors, barriers to use and recommended solutions

Whilst the inhaled route is the first line administration method in the management of asthma, it is well documented that patients can have problems adopting the correct inhaler technique and thus receiving adequate medication. This applies equally to metered dose inhalers and dry powder inhalers and leads to poor disease control and increased healthcare costs. Reviews have highlighted these problems and the recent European Consensus Statement developed a call to action to seek solutions. This review takes forward the challenge of inhaler competence by highlighting the issues and suggesting potential solutions to these problems. The opportunity for technological innovation and educational interventions to reduce errors is highlighted, as well as the specific challenges faced by children. This review is intended as a policy document, as most issues faced by patients have not changed for half a century, and this situation should not be allowed to continue any longer. Future direction with respect to research, policy needs and practice, together with education requirements in inhaler technique are described.

Deposition of small particles in the developing lung

Infancy is a time of marked and rapid changes in respiratory tract development. Infants (0-1 year of age) and young children (1- 3 years of age) are a unique subpopulation with regard to therapeutic aerosols. Anatomical, physiological and emotional factors, peculiar to these age groups, present significant challenges for aerosol delivery to the respiratory tract. Most studies with inhaled corticosteroids (ICS) have administered aerosols with relatively large particles, frequently > 3 μm in mass median aerodynamic diameter (MMAD). These drugs were designed for use in adults and older children and were administered with masks which were frequently rejected by children under age 3-4 years. We review the reasons that large-particle aerosols are likely to be less effective in infants and young children. We suggest that the benefit of inhaled medications in this age group requires further evaluation to determine if better therapeutic outcomes might be achieved using smaller particles and more patient-friendly delivery systems.

Lung function changes in asthmatic children treated with HFA-BDP

STUDY OBJECTIVES

Asthma guidelines suggest that normal or near normal lung function should be one of the goals for good asthma control. Therefore, children with chronic persistent asthma and reduced peripheral airway function were assessed after the replacement of conventional inhaled corticosteroids (ICS) with an extrafine aerosol formulation, hydrofluoroalkane-134a beclomethoasone diproprionate (HFA-BDP).

DESIGN AND SETTING

Lung function and clinical details were studied in children with moderate persistent asthma who regularly attended the pediatric pulmonary outpatient clinic at Kosair Children's Hospital, Louisville, Kentucky, USA.

SUBJECTS

A total of 20 children, 7 girls and 13 boys, with stable asthma but reduced forced expiratory flows between 25% and 75% of vital capacity (FEF(25-75) ) were included in the study.

INTERVENTION

After the initial assessment, each subject was switched from conventional ICS to HFA-BDP. All other medications remained the same. Reassessment of lung function and clinical status was performed at least 3 weeks after the intervention.

RESULTS

FEF(25-75) increased from a mean of 50.75% to 68.85% predicted (P < 0.001). Forced expiratory volume in 1 sec (FEV(1)) also increased significantly from 84.6% to 93.8% predicted (P = 0.001). No changes asthma symptoms were observed.

CONCLUSION

Compared to conventional ICS, the use of HFA-BDP in asthmatic children significantly improves airflow in both the large and the peripheral airways without loss of asthma control.

A pilot study to assess lung deposition of HFA-beclomethasone and CFC-beclomethasone from a pressurized metered dose inhaler with and without add-on spacers and using varying breathhold times

BACKGROUND

The study objective of this pilot study was to determine the lung delivery of HFA-134a-beclomethasone dipropionate (HFA-BDP; QVAR™) and CFC-beclomethasone dipropionate (CFC-BDP; Becloforte™) with and without the add-on spacers, Aerochamber™, and Volumatic™. The smaller particles of HFA-BDP were presumed to produce greater lung deposition using spacers, with and without a delay [i.e., metered dose inhaler (MDI) actuation into the spacer and subsequent inhalation 0 and 2 sec later], compared with the larger particles of CFC-BDP. The study included a comparison of breathhold effects (i.e., 1 and 10-sec breatholds) on lung deposition.

METHODS

The study was an open-label design and utilized healthy subjects (n = 12 males). Each arm of the study contained three subjects; thus, outcomes were not powered to assess statistical significance. HFA-BDP and CFC-BDP were radiolabeled with technetium-99m and delivered to subjects.

RESULTS

Results showed that the small particle HFA-BDP lung deposition averaged 52% and was not affected by the use of Aerochamber with or without a spacer delay. The oropharyngeal deposition of HFA-BDP was reduced from approximately 28% to 4% with the Aerochamber. Lung deposition with the large particle CFC-BDP was 3-7% and generally decreased with Aerochamber or Volumatic. A 2-sec time delay between actuation and breath plus the spacer reduced lung deposition slightly but reduced oropharygeal deposition substantially (84% down to 3-20%) using the Aerochamber or Volumatic with and without a spacer delay. HFA-BDP lung deposition was dependent on the breathhold. Lung deposition with HFA-BDP was reduced by 16% with a 1-sec versus 10-sec breathhold. The difference was measured in the increased exhaled fraction, confirming that smaller particles need time to deposit and are exhaled if there is a reduced breathhold. The large particle CFC-BDP lung deposition was not affected by breathhold.

CONCLUSIONS

The use of Aerochamber or Volumatic spacers with HFA-BDP did not alter lung deposition but it did reduce oropharyngeal deposition. However, HFA-BDP displayed reduced oropharyngeal deposition without a spacer.

Factors that affect the efficacy of inhaled corticosteroids for infants and young children

Infants (0-1 years of age) and young children (1-3 years of age) are a unique subpopulation with regard to inhaled therapies. There are various anatomic, physiological, and emotional factors peculiar to this age group that present significant difficulties and challenges for aerosol delivery. Most studies of therapeutic aerosols that have been performed with patients of this age group, particularly recent studies with inhaled corticosteroids (ICSs), administered aerosols with relatively large particles (ie, >3 microm in mass median aerodynamic diameter). These drugs were designed for use in adults and older children and were administered with masks, which are frequently rejected by patients. Based on these studies, it was recently suggested that ICSs might not be as therapeutically effective in infants and young children as in adults. We review the reasons that large-particle corticosteroid aerosols are not likely to be effective in infants and young children. This patient population differs from adults in airway anatomy and physiology, as well as in behavior and adherence to therapy. We suggest that the benefit of ICSs in this age group requires further evaluation to determine whether better therapeutic outcomes might be achieved with smaller particles.

Particle size of inhaled corticosteroids: does it matter?

A question with respect to asthma therapy revolves around the issue of whether better efficacy occurs with an ultrafine-particle inhaled corticosteroid because of better lung deposition into the distal airways. This article reviews particle size and delivery devices of different steroids, clinical outcomes of small- versus large-particle steroids, and the issue of pharmacoeconomics.

The rejuvenated pressurised metered dose inhaler

The pressurised metered-dose inhaler (pMDI) has now been available for 50 years. Once regarded as an inefficient and difficult-to-use device, the technology has evolved significantly over the last few years, particularly since the introduction of novel formulations containing hydrofluoroalkane (HFA) propellants. Many modern HFA pMDIs deposit drug more efficiently in the lungs, impact less forcefully on the back of the throat and feel less cold than their chlorofluorocarbon pMDI counterparts. An improved understanding of technical factors makes it possible to design HFA pMDIs to have specific spray properties, particularly in terms of fine particle dose and spray velocity. Device technology has also progressed with the introduction of compact and convenient breath-actuated, breath-coordinated and velocity-modifying devices, which help patients to achieve a reliable lung dose. Although it faces competition from dry powder inhalers and possibly from novel soft-mist inhalers containing liquid formulations, the rejuvenated HFA pMDI is a device with a significant future for asthma, chronic obstructive pulmonary disease and wider treatment indications.

Aerosol therapy: the special needs of young children

Efficient aerosol therapy in young children is a challenge. The aerosol administration method requires special features, because young children can not perform an inhalation manoeuvre, breath usually through the nose and may be distressed during the administration. The prescribing clinician should be aware of the advantages and disadvantages of the different inhalation devices available, in order to select the proper device for each individual patient. For maintenance asthma therapy in young children the pressurized metered dose inhaler (pMDI) combined with spacer is the first choice for delivering aerosols. A facemask can be attached if a child is unable to breath through the mouth. A small leak of the facemask can reduce the dose delivered dramatically, therefore a good seal is crucial. Lung deposition can be improved by using a pMDI with extra-fine particles. However, even if the most optimal device is chosen, cooperation during administration remains the most important determinant for efficient drug delivery. During crying the dose to the lungs is minimal. Optimal aerosol delivery to the lungs of young children can be achieved with a good facemask seal, good cooperation of the child, with quiet breathing and an aerosol with small particles.

The customised electronic nebuliser: a new category of liquid aerosol drug delivery systems

Inhalation of aerosols is the preferred route of administration of pharmaceutical compounds to the lungs when treating various respiratory diseases. Inhaled antibiotics, hormones, peptides and proteins are potential candidates for direct targeting to the site of action, thus minimising systemic absorption, dilution and undesired side effects, as much lower doses (as low as a fiftieth) are sufficient to achieve a similar therapeutic effect, compared with oral administration. A quick relief from the symptoms and a good tolerance are the main advantages of aerosol therapy. A new class of electronic delivery device is now starting to enter the market. The eFlow electronic nebuliser (PARI GmbH, Germany) provides improved portability and, in some instances, cuts treatment time to only a fraction of what has been experienced with current nebulised therapy. Drug formulations and the device can be mutually adapted and matched for optimal characteristics to meet the desired therapeutic target. Reformulation of known and proven compounds in a liquid format are commercially attractive as they present a relatively low development risk for potential drug candidates and, thus, have become a preferred pathway for the development of new inhalation products.

In VitroValidation of99mTc-HFA-FP Delivered via pMDI-Spacer

The purpose of the study was to label Flixotide (fluticasone propionate [FP] with HFA propellant), with technetium-99m and validate that (99m)Tc acts as a suitable marker for FP when delivered via pMDI-spacer. Sodium pertechnetate was mixed with 5 mL of butanone. (99m)Tc was extracted into butanone and transferred into an empty canister. The (99m)Tc lined canister was heated, and the butanone evaporated to dryness. A supercooled commercial Flixotide canister was decrimped, and the contents transferred to the (99m)Tc lined canister and recrimped. The particle size distribution of FP and (99m)Tc from 10 radiolabeled canisters was measured using an Anderson cascade impactor calibrated to 28.3 L/min, and compared to commercial FP. The drug (FP) content of each particle size fraction was measured using ultraviolet spectrophotometry and the (99m)Tc level in each fraction was measured using an ionization chamber. The percentage of particles in the fine particle fraction (<;4.7 microm) and the percentage of (99m)Tc from commercial and radiolabeled canisters were compared. The mean (SD) % FP in the fine particle fraction, before and after label was 43.2 (1.8) % and 43.9 (2.6) %, respectively. The mean (SD) % (99m)Tc in the fine particle fraction was 42.1 (5.1) %. The mean %FP exiting spacer at (<4.7 microm) before labeling was not significantly different from the mean % FP exiting spacer at (<4.7 microm) after labeling (p > 0.05). The mean % (99m)Tc attached to particles at (<4.7 microm) after radiolabeling was not significantly different from the mean % FP levels (p > 0.05). The validation in this study indicates that (99m)Tc can act as a suitable marker for HFAFP, delivered via pMDI-spacer.

Effect of Oropharyngeal Length in Drug Lung Delivery via Suspension Pressurized Metered Dose Inhalers

PURPOSE

To determine the effect of the oropharyngeal length in adults on the lung dose of a suspension pressurized metered dose inhaler, and whether employing small volume spacers can alter this role.

METHODS

Depositions of Ventolin Evohaler (100) microg in the oropharyngeal models of two healthy adult subjects with 17.1 cm (short cast) and 19.9 cm (long cast) centerline lengths via three small volume spacers [two spacers with 3 cm effective length but one with 6.5 cm2 (L3) and the other with 24.6 cm2 (L3W) cross sections, and the Optimiser] were studied.

RESULTS

Without using spacers, lung dose of the long cast (19.52 +/- 2.32 microg, mean +/- standard deviation) was significantly larger than that for the short cast (8.08 +/- 1.01 microg, p < 0.006). However, using the L3 spacer with the short cast made the lung dose (18.59 +/- 3.33 microg) similar to that for the long cast alone. Lung doses of the short cast (20.43 +/- 1.42 microg) and the long cast (30.81 +/- 1.84 microg) with the L3W spacer were similar to those with the L3 spacer. However, using the Optimiser spacer increased the lung dose for the short cast (22.27 +/- 6.03 microg) and significantly for the long cast (35.61 +/- 2.19 microg, p < 0.006) compared to those for the L3 spacer. Using spacers increased drug deposition in the oropharynx part of the short cast, and this reduced the lung dose compared to that for the long cast.

CONCLUSION

The oropharyngeal length in adults may affect the lung dose via the pMDIs, which may not be eliminated by using small volume spacers.

Recent advances in aerosol therapy for children with asthma

Inhalational drug delivery is the primary mode of asthma therapy in children and is the main focus of this article. Pressurized metered dose inhalers (pMDIs) are now the method of choice in infants and children under 5 years old, when used in combination with an appropriate valved holding chamber or spacer. Spacers are particularly important for steroid inhalation to maximize lung deposition and minimize unwanted oropharyngeal deposition. Optimal inhalation technique with a pMDI-spacer in infants is to inhale the drug by breathing tidally through the spacer. Drug delivery to the lungs using pMDIs can vary greatly, depending on the formulation used and the age of the child. Dry powder inhalers (DPIs) are driven by the peak inspiratory flow of the patient and are usually not appropriate for children under 5 or 6 years of age. Nebulizers continue to play a role in the treatment of acute asthma where high doses of bronchodilator are required, though multiple doses via pMDI spacer may suffice. Important drug delivery issues specific to children include compliance, use of mask versus mouthpiece, lower tidal volumes and inspiratory flows, determination of appropriate dosages, and minimization of adverse local and systemic effects.

Pharmacokinetic and pharmacodynamic properties of inhaled beclometasone dipropionate delivered via hydrofluoroalkane-containing devices

Inhaled corticosteroids have a key role in the treatment of asthma and chronic obstructive pulmonary disease. In recent times, beclometasone dipropionate has been reformulated in pressurised metered dose inhalers (pMDIs), using hydrofluoroalkanes (HFAs) as a propellant. Extensive toxicological testing has shown that HFA-propellants are well tolerated. Among the reformulated beclometasone dipropionate-containing pMDIs, only the characteristics of the two Qvar formulations have been thoroughly explored. Compared to the reference beclometasone dipropionate formulation, the mass median aerodynamic diameter of the Qvar formulations are substantially smaller (1.1 vs 4.0 microm), whereas that of Modulite averages 2.6 microm. Scintigraphic and pharmacokinetic studies indicate a higher lung deposition for both the Qvar and the Beclazone formulations, compared with reference beclometasone dipropionate formulation. Since the 2- to 3-fold increase in pulmonary deposition results in a 2.6- to 3-fold difference in relative efficacy for Qvar, half the dose of the reference beclometasone dipropionate formulation has been currently recommended in adult patients with asthma, a recommendation that is supported by a large number of clinical trials. Conversely, the design of the studies conducted to compare the efficacy of Qvar with fluticasone propionate and budesonide does not allow establishing their equivalence on a milligram per milligram basis. Good studies on the bioequivalence between the reference beclometasone dipropionate formulation and the Modulite or Beclazone formulations are not available.

Factors guiding the choice of delivery device for inhaled corticosteroids in the long-term management of stable asthma and COPD: focus on budesonide

Inhaled corticosteroids (ICSs) have become the mainstay of chronic controller therapy to treat airways inflammation in asthma and to reduce exacerbations in chronic obstructive pulmonary disease. An array of ICSs are now available that are aerosolized by a range of delivery systems. Such devices include pressurized (or propellant) metered-dose inhalers (pMDIs), pMDIs plus valved holding chambers or spacers, breath-actuated inhalers, and nebulizers. More recently, dry-powder inhalers (DPIs) were developed to help overcome problems of hand-breath coordination associated with pMDIs. The clinical benefit of ICSs therapy is determined by a complex interplay between the nature and severity of the disease, the type of drug and its formulation, and characteristics of the delivery device together with the patient's ability to use the device correctly. The ICSs budesonide is available by pMDI, DPI, and nebulizer-allowing the physician to select the best device for each individual patient. Indeed, the availability of budesonide in three different delivery systems allows versatility for the prescribing physician and provides continuity of drug therapy for younger patients who may remain on the same ICSs as they mature.

[The role of the small airways in childhood asthma]

INTRODUCTION

Asthma, the most common chronic disease in paediatrics, is characterised by an inflammatory process involving the proximal and distal airways, with remodelling of the airways and changes in respiratory function.

STATE OF THE ART

Recent studies in children have provided evidence of damage to the small airways identical to that occurring in adults. In fact inflammatory cells as well as structural alterations of the airways have been found in both bronchial biopsies and broncho-alveolar lavage fluid in infants and young children. At the functional level this damage is manifest by a reduction in maximum expiratory flow rates between 25-75% of the vital capacity. It also shows itself by the demonstration of thick walled bronchi and hypodense bands on the high resolution CT scan. It appears that conventional inhaled treatments have no effect on the small airways. Finally the main prognostic factors for this distal damage are respiratory infections and exposure to tobacco in utero.

PERSPECTIVES

Damage to the small airways in childhood asthma indicates the need for new therapies aimed at this part of the respiratory system.

CONCLUSION

Inflammation and remodelling of the small airways develops early in an asthmatic child whose respiratory system is growing rapidly and persists throughout life.

Deposition of aerosols in infants and children

There is still a lack of knowledge in the field of aerosol therapy in children, particularly in young children. The amount of drug delivered from a commercially available inhalation device that reaches the lungs of children is generally low. The choice of an optimal combination of delivery device and drug formulation based on individual patient related factors is crucial. Aerosols with a small MMAD and a narrow GSD are required for a sufficient inhalation therapy in early childhood. The development of combinations of delivery devices and drug formulations fulfilling the requirements for an efficient inhalation therapy in young children is likely to increase the therapeutical options in this age group.

The efficacy and safety of QVAR (hydrofluoroalkane-beclometasone diproprionate extrafine aerosol) in asthma (Part 2): Clinical experience in children

QVAR [hydrofluoroalkane-134a beclometasone dipropionate (BDP)] produces equivalent asthma control to chlorofluorocarbon-based BDP inhalers, at approximately half the daily dose in adults, a probable consequence of the increased lung deposition of QVAR that results from its greater fine particle fraction. Recent studies have relied on the clinical experience with QVAR in adults as a basis for investigations in childhood asthma. Design considerations, such as the use of the breath-actuated Autohaler delivery device and measurement of direct health benefits, account for problems of variation in inspiratory flow, handling difficulties and low airways resistance that are associated with children. QVAR appears to be well tolerated in children with no clinically relevant adverse effects on adrenal function, bone metabolism or growth at recommended doses.