PURPOSE: This in vitro study reports estimates of lung delivery of the two asthma medications Xopenex HFA and Flovent HFA delivered via Vortex and AeroChamber holding chambers. Such information is useful in guiding clincians’ choice of a holding chamber for a specific MDI.
METHODS: Xopenex HFA and Flovent HFA were tested alone and with Pari Vortex, and AeroChamber Plus holding chambers. Each device was mounted onto an aluminum idealized mouth-throat replica (the Alberta Geometry) with downstream filter. The mouth-throat geometry was coated with silicone release spray to avoid particle bounce. Inhalation was simulated (initial 1 l/s2 flow acceleration reaching a subsequently constant 28.3 l/min flow rate after 0.47 sec. for 3 litre total inhaled volume) using a breathing machine downstream. Five inhaler actuations were used in each tests. After completion of each test, the mouth-throat replica and each filter were extracted three times and assayed using UV spectroscopy. Statistical significance was assumed if p< 0.05.
RESULTS: Mouth-throat deposition was reduced to undetectable levels for both holding chamber models, compared with 47% of label dose with MDI-alone for Flovent HFA and 46% with Xopenex HFA. As % of label claim, delivery distal to the mouth-throat for Flovent HFA was 42.7(1.8)% for MDI-alone, 36.5(2.0)% for AeroChamber Plus, and 48(2.9)% for Vortex, while for Xopenex HFA it was 38.7(2.9)% for MDI-alone, 39.7(2.0)% for AeroChamber Plus, and 55.1(0.4)% for Vortex. Standard deviation (n=3) is given in brackets.
CONCLUSION: The Vortex holding chamber gives significantly higher delivery distal to the mouth-throat than the AeroChamber Plus for both tested MDIs. Both holding chambers significantly reduce mouth-throat deposition.
CLINICAL IMPLICATIONS: In vivo studies would be useful to confirm the present in vitro findings that the Vortex holding chamber gives increased lung deposition compared with the AeroChamber Plus.
DISCLOSURE: Peter Zuberbuhler, Grant monies (from industry related sources) This study was funded by Pari.; No Product/Research Disclosure Information