In vitro testing of the new Space Chamber Slim with salbutamol sulfate, fluticasone propionate, and ipratropium bromide pressurized metered dose inhalers
Michael Nairn1, Andrew Lorbeer1, Kurt Nikander2, Scott Courtney1
1Medical Developments International Limited, 4 Caribbean Drive, Scoresby, 3179, Australia
2InDevCo AB, Handbollsvagen 1B, Nykoping, 61164, Sweden
Summary
In vitro aerodynamic particle size distribution testing was performed on a new disposable cardboard spacer – the Space Chamber Slim (SCS; Medical Developments International Limited, Australia) – along with a similar marketed valved holding chamber – the LiteAire (LA; Thayer Medical Corporation, USA). The devices have similar holding chamber volumes (SCS ~200 mL; LA 184 mL), but their designs differ in terms of internal geometry and vent/valve organisation. Therefore, it is important to quantify how these variations affected the drug delivery characteristics of the devices. Pressurized metered dose inhalers (pMDIs) were used to deliver three common aerosolised medications through the devices into a cascade impactor at constant paediatric (for salbutamol sulfate) and adult flow rates (for salbutamol sulfate, fluticasone propionate, and ipratropium bromide). Both devices substantially reduced the total mass of drug delivered to the impactor, while increasing the proportion of fine (≤4.7 µm) particles within the delivered aerosols by at least two-fold (e.g. 37 % with pMDI alone versus 78 % with the SCS for salbutamol at 30 L/min). The SCS and LA devices performed similarly (within 15 % of one another at the 90 % confidence interval) with regard to their fine particle fractions. However, the fine particle dose was slightly (but significantly; P<0.05) higher with the Space Chamber Slim in all instances. The results indicate that, at the conditions tested, the Space Chamber Slim is highly effective in reducing the delivery of undesirable coarse particles compared with pMDIs alone, while either not affecting or increasing the delivery of fine particles.