Valved holding chamber (VHC) spacers are recommended for users unable to coordinate actuation of the pMDI with inhalation of aerosolized drug and/or to avoid potential drug-related events (eg. high-dose inhaled corticosteroid-induced oral candidiasis). VHC use is commonplace among young children, and national/international recommendations exist for their use. Drug manufacturers routinely validate VHCs against their aerosol products to provide guidance and recommendations. A similar in vitro evaluation of the new Clement Clarke A2A Spacer® VHC (A2A) has been conducted at an independent laboratory. A2A is differentiated from
other VHCs by inclusion of an anti-microbial additive throughout the device- and interchangeable mask-polymers that also confers considerable anti-static properties. A2A has been investigated inter- and intra-sample, through lifetime, and compared with AeroChamber® VHC and pMDI without spacer; determining the aerosol characteristics of Ventolin® HFA. Particle size, GSD, total dose delivered, and respirable, coarse, fine and ultrafine particle fraction data were determined using an Andersen Cascade Impactor operated to FDA methodology.
There were no significant differences between A2A samples for any aerosol characteristic (F-statistic < 4.74, ns). A2A passed all functional and visual lifetime tests, with no significant post-test differences in aerosol characteristics (t < 2.78, ns). Both VHCs significantly affected total delivered dose and coarse particle fraction – an expected outcome, with the VHCs trapping the larger non-respirable particles. The data indicate that A2A will be a useful additional VHC choice with bacterio- and fungi-static properties