Drug delivery and adherence in young children.

The aim of this pilot study was to compare a the HaloLite Paediatric Nebulizer (HPN) with a pressurized metered dose inhaler and valved holding chamber (pMDI VHC, Aerochamber) in terms of drug delivery, adherence to treatment, compliance with device, true adherence, and acceptability. Fourteen children aged 11-36 months with asthma on regular treatment with inhaled corticosteroids were enrolled into an open, randomized, crossover trial. They received budesonide for 2 weeks with each delivery system. Both devices incorporated a datalogger which recorded information on how the device was used. The HPN was preprogrammed to deliver 25 microg of budesonide to the patient. A single actuation of budesonide 200 microg was used with the pMDI VHC. The median delivered dose of budesonide was 36 microg (range, 31-45 microg; CV, 15%) for the HPN and 53 microg (range, 17-85 microg; CV, 47%) for the pMDI VHC. The median adherence was 68% (range, 11-96%) with the HPN and 71% (range, 11-100%) with the pMDI VHC. The median device compliance was 30% and 51% and the median true adherence was 23% and 36%, respectively. The shape, size, and weight of the HaloLite Paediatric Nebulizer were generally less acceptable than the shape, size, and weight of the pMDI VHC with datalogger. These results indicate that reproducible quantities of drug can be delivered to very young children using AAD technology such as that incorporated into the HPN. Drug delivery with the pMDI VHC was more variable, but parents preferred this device.

Intra-subject variability in lung dose in healthy volunteers using five conventional portable inhalers.

High intra-subject variability in lung dose achieved when using aerosol delivery systems may impact on the efficacy of treatment in clinical practice. While the dose delivered by metered dose inhalers (pMDIs) is highly reproducible when tested in vitro, the variability in dose delivered to the lungs is known to be high. It has been suggested that newer delivery systems such as dry powder inhalers (DPIs) or breath actuated pMDIs significantly reduce the intra-subject variability in lung dose, but this remains untested. The 30-min urinary salbutamol technique was used to assess intra-subject variability in lung dose for five portable inhaler devices. Thirteen healthy adult subjects inhaled salbutamol from five different devices. Each device was used at five separate study days, a total of 25 visits. The devices studied were the Evohaler pMDI, a pMDI with Volumatic (pMDI + HC), the Easibreath, the Accuhaler and the Turbohaler. Subjects inhaled 400 microg of salbutamol and produced a urine sample exactly 30 min later. Quantities of salbutamol contained in the urine were determined using an HPLC technique. The mean coefficient of variation (CV% and range) for lung dose were 31.8% (20.1-87.4) for the pMDI + HC, Easi-breathe 35.9% (10.4-66.2), Accuhaler 40.4% (15.6-75.2), Turbohaler 42.4% (20.7-74.2), and 52.0% (27.1-49.3) for the pMDI alone. There was no significant statistical significant difference between any of the devices. In seven of 13 subjects, the greatest lung dose was achieved with the Volumatic. The observed intra-subject in health volunteers is similar to the reported intra-subject variability of bioavailability for a number of oral medications. Though there was trend towards higher variability when using the pMDI, this was not statistically significant and was largely attributable to one subject in with a poor technique.

Majority of children aged 3 years and above can reliably inhale through the Clickhaler.

Guidelines suggest that pressurized metered dose inhalers (pMDI) plus spacers are the delivery system of choice for children. However, they are bulky, which makes them inconvenient. It was suggested that the smaller dry-powder inhalers (DPIs) may be suitable for delivering short-acting bronchodilators to preschool children. This study considered whether preschool children could reliably generate sufficient inspiratory flows to use the Clickhaler DPI. Twenty-seven asthmatic and 34 nonasthmatic children, aged 2-5 years, were recruited. Following training, they were asked to inhale four times through a Clickhaler flow monitoring system, twice "steadily" and twice "forcefully." Inspiratory flow data were collected during each inhalation. Of the 3-, 4-, and 5-year-old asthmatics, 62.5, 100, and 100%, respectively, could reliably differentiate between inhaling and exhaling through the DPI. For nonasthmatics, the figures were 66, 60, and 88%, respectively. All but one of the children who understood the instructions generated a PIF of greater than 15 l/min (range, 13.9-88.3 l/min and 21.2-84.5 l/min in asthmatic and nonasthmatic children, respectively). These data indicate that the majority of children aged 3 years and above could reliably inhale rather than exhale through a dry-powder inhaler, and that they generate inspiratory flows sufficient to use the Clickhaler effectively. The results indicate that the device could be a suitable delivery system for beta(2)-agonists in preschool children.