The aim of the present study was to measure airway, oropharyngeal and gastrointestinal deposition of 99m Tc-labelled hydrofluoroalkane-beclomethasone dipropionate after inhalation via a pressurised metered-dose inhaler and spacer (Aerochamber Plus TM ) in asthmatic children.A group of 24 children (aged 5-17 yrs) with mild asthma inhaled the labelled drug. A total of 12 children took five tidal breaths after each actuation (tidal group). The other 12 children used a slow maximal inhalation followed by a 5-10-s breath-hold (breath-hold group). Simultaneous anterior and posterior planar c-scintigraphic scans (120-s acquisition) were recorded.For the tidal group, mean¡SD lung deposition (% ex-actuator, attenuation corrected) was 35.4¡18.3, 47.5¡13.0 and 54.9¡11.2 in patients aged 5-7 (n54), 8-10 (n54) and 11-17 yrs (n54), respectively. Oropharyngeal and gastrointestinal deposition was 24.0¡10.5, 10.3¡4.4 and 10.1¡6.2. With the breath-hold technique, lung deposition was 58.1¡6.7, 56.6¡5.2 and 58.4¡9.2. Oropharyngeal and gastrointestinal deposition was 12.9¡3.2, 20.1¡9.5 and 20.8¡8.8.Inhalation of the extrafine formulation with the breath-hold technique showed significantly improved lung deposition compared with tidal breathing across all ages. Oropharyngeal and gastrointestinal deposition was markedly decreased, regardless of which inhalation technique was applied, compared with a previous paediatric study using the same formulation delivered via a breath-actuated metered-dose inhaler.

Lung deposition achieved using the spacer with facemask was higher than previously reported, with a difference of only 4.4% of total dose measured compared to the deposition with mouthpiece. This may be due to a combination of factors including pMDI formulation, and use of an antistatic spacer with a flexible, well-fitting facemask.

Drug delivery to patients using dry powder inhalers, such as the Turbuhaler®, is believed to be influenced by the inspiratory flow used. Clinical studies have indicated that this delivery system can be used effectively by children. However, it is not known how the total and weight-corrected dose delivered to the airways varies with age. A deposition study using technetium-99m ( 99m Tc)-labelled budesonide was performed in order to determine the effect of age on delivery.Twenty one children with cystic fibrosis, aged 4-16 yrs, were recruited. They were clinically stable with normal lung function. Initially, a gamma camera scan was taken in front of a flood source containing 37 MBq of 99m Tc. Subsequently, subjects inhaled through a low resistance inspiratory filter connected to a commercially available Turbuhaler®. Immediately afterwards they inhaled from a noncommercial Turbuhaler® containing budesonide labelled with 99m Tc, and then underwent anterior and posterior gamma camera scans. Both Turbuhaler® inhalers were attached to a portable spirometer and the peak inspiratory flow through the Turbuhaler® was recorded for each inhalation. The total body dose was calculated from the dose deposited on the inspiratory filter connected to the commercial Turbuhaler®. Analysis of the gamma camera images provided information on the proportion of the radiolabel delivered to the lungs compared to that deposited in the upper airway and stomach.As expected, a highly significant positive correlation was noted between the peak inspiratory flow generated by the patient through the Turbuhaler® and the dose delivered to the lung. Similarly, there was a highly significant positive correlation between age and "total lung dose". However, when total lung dose was corrected for body weight, there was a nonsignificant negative correlation with age. This study suggests that the "weight-corrected lung dose" achieved when children aged >6 yrs use the Turbuhaler®, is largely independent of age. It would appear that the flow-dependent properties of this device are such that the reduced peak inspiratory flow generated by younger children results in a lower dose to the lungs, but that this is off-set by their lower body weight. This is unlikely to be a property of other devices with different flow/drug delivery characteristics. Eur Respir J 1997; 10: 2023-2028 The convenience and ease of use of Turbuhaler®, a multidose dry powder inhaler (DPI), has resulted in its widespread use for the treatment of children with respiratory disease. Scintigraphic and pharmacokinetic deposition studies have indicated that this device is capable of delivering a mean of 20-30% of the nominal dose to the lungs of adults [1,2]. Although it is difficult to compare results from studies utilizing different methods [3], these results suggest that the device delivers a greater proportion of the nominal dose to the lungs of adult patients than do other DPIs [4,5], metereddose inhalers (MDIs) [4,6,7], and jet nebulizers [8,9], and these results are similar to o...

Total lung deposition of radiolabelled budesonide from a dry powder inhaler (Turbuhaler), is age dependent in children with moderate asthma. However, lung deposition is still satisfactory, even in younger children with lower peak inspiratory flows.

We have shown that by using an improved age-adjusted complementary combination of delivery device and drug formulation to deliver small particles, lung deposition and ratio of lung deposition to oropharyngeal deposition in young asthmatic children is highly improved. But the main factor limiting aerosol delivery in this age group remains cooperation.