In vitro comparison of aerosol deposition by albuterol pMDI using corrugated tubing versus a commercial spacer

Commercial spacers are attachments used with pressurised metered dose inhalers (pMDI) which help improve lung delivery and reduce oropharyngeal deposition of the medication by slowing down the aerosol plume emitted from the device and retaining larger particles within the spacer. However, their cost may limit accessibility in resource constrained settings. Corrugated anaesthetic tubing has been used as a low-cost alternative spacer, though its aerosol performance has not been characterised. This study quantitatively compared in vitro aerosol deposition of albuterol (Ventolin®) delivered under three setups: with a 6′’ corrugated tubing spacer, with a commercially available spacer device (E-Chamber La Grande) and without a spacer. Aerosol performance was evaluated using a Next Generation Impactor (NGI). Delivered dose (DD), fine particle dose (FPD), fine particle fraction (FPF), and mass median aerodynamic diameter (MMAD) parameters were assessed. Corrugated tubing produced significantly lower FPD at the 200 µg and 300 µg doses (corresponding to two and three actuations, respectively), indicating reduced delivery of respirable drug to the lungs and a potential reduction in clinical effectiveness. The commercial spacer generally demonstrated higher FPD than corrugated tubing and more uniform deposition patterns across the tested conditions. Spacer selection significantly influences aerosol delivery from pMDIs. While corrugated tubing represents a practical low-cost alternative, its reduced aerosol performance may compromise therapeutic efficacy. Commercial spacers remain the preferred option in practice, although performance depends on device configuration and test conditions. Further optimisation of affordable spacer designs is warranted for resource limited environments.