The ex vivo output of budesonide (Pulmicort^®) from NebuChamber^® and other holding chambers (including Nebuhaler^®) has been investigated in children aged 6 months to 6 years with suspected asthma (Bisgaard et aI, 1995). The children inhaled budesonide via CFC pMDI with NebuChamber and Nebuhaler, and the mean dose delivered with NebuChamber was 39% of the nominal dose and 21% with Nebuhaler. Thus, the ex vivo drug delivery corresponded to the figures found in vitro. This is consistent with the findings of Berg et al(1998) that drug delivery during simulated breathing was comparable with the maximum output measured in vitro.

In a study in adult patients with mild asthma, lung deposition of budesonide (Pulmicort pMDI) with NebuChamber and Nebuhaler was investigated. Priming the holding chambers had no effect on lung deposition from NebuChamber (unprimed 32.9%, primed 33.5%) but it significantly increased lung deposition from Nebuhaler (unprimed 26.7%, primed 37.7%; p=0.01) (Kenyon et aI,1998). For both devices, deposition in the central, intermediate and peripheral zones of the lung increased equally, and therefore there was no change in the distribution of budesonide deposition in the lungs.

Drug deposition with NebuChamber was equivalent to that seen with Nebuhaler, despite the fact that the volume of NebuChamber is only about one third that of the other device.

References

Berg E, et al. In vitro performance of three combinations of valved holding chambers and pressurized metered dose inhalers for treatment in children. Eur Respir J 1998;12:472-6.

Bisgaard H, et al. A non-electrostatic valved holding chamber for aerosol delivery. Arch Dis Child 1995;73:226-30.

Kenyon CJ, et al. The effects of static charge in valved holding chambers on glucocorticosteroid aerosol deposition in asthmatic patients. Eur Respir J 1998;11:606-10.