Assessment of Emergency Spacers Versus Traditional Spacers, An In-Vitro Model for Aerosol Delivery

Abstract

Spacers, when used with pressurized metered dose inhalers (pMDIs), enhance aerosol drug delivery and address coordination challenges during inhalation. This study aimed to compare the efficacy of emergency spacers with traditional spacers in delivering salbutamol aerosol from pMDIs. The total emitted dose (TED) and particle size distribution of salbutamol were determined using an Andersen MKII cascade impactor. The study evaluated pMDI alone and with various spacers, including traditional antistatic spacers (Able, Tips-Haler, Aerochamber Plus Flow Vu, Atomizer Chamber) and emergency spacers (Plastic juice cup, MDI PLUS, Lite-Air spacer, DispozABLE spacer, and Paper sheet spacer) at a flow rate of 28.3 L/min with inhalation volumes of 2 L and 4 L, representing children (> 6 years) and adults, respectively. The pMDI alone delivered the highest TED, significantly exceeding all pMDI-spacer combinations at both inhalation volumes (P < 0.001-0.033), except for the Aerochamber Plus Flow Vu at 2 L. The Aerochamber Plus Flow Vu achieved significantly higher TED compared to emergency spacers and the Atomizer Chamber (P < 0.001-0.039) and was non-significantly higher than the Able and Tips-Haler spacers. It also delivered the highest fine particle dose (≤ 5 µg) and exhibited the lowest mass median aerodynamic diameter (MMAD) with significant differences across devices. Traditional spacers, particularly the Aerochamber Plus Flow Vu, demonstrated superior performance in TED and aerodynamic particle size distribution. However, emergency spacers remain viable alternatives in urgent situations due to their acceptable delivery efficiency.

Keywords: PMDI; aerosol delivery; emergency spacers; salbutamol; valved holding chambers.