Evaluation of a cardboard-based spacer for enhancing aerosol delivery from pressurized metered dose inhalers.

Objective: The current study aimed to evaluate a novel paper card-based spacer (MDI Plus) in vitro and in vivo as a cost-effective alternative to traditional spacers (AeroChamber Plus).

Methodology: The in vitro part evaluated salbutamol's aerodynamic particle size distribution (APSD) after 0, 20, 50, 120, and 200 uses of Ventolin pressurized metered dose inhaler (pMDI) when connected to MDI Plus using an Andersen cascade impactor at an inhalation flow of 28.3 L/min. The in vivo part recruited a cohort of adult asthmatic patients. It assessed their pMDI usage and the number of training sessions to enhance their ability to use their pMDI alone and in combination with MDI Plus and AeroChamber Plus. Moreover, the amount of salbutamol deposited within the spacer devices, on the pMDI, and on the hand of the patients after 0, 20, 50, 120, and 200 uses were evaluated.

Results: The durability tests revealed that while there were reductions in aerodynamic performance over the lifespan of the pMDI, the decreases were insufficient to render the spacer ineffective. The fine particle fraction decreased slightly, and the mass median aerodynamic diameter increased somewhat, but the spacer maintained functional performance. The study indicated that spacers significantly improved patients' ability to use their MDIs correctly with minimal training. The MDI Plus showed a slightly significant positive impact (p < 0.05), requiring fewer training sessions for effective use. The amount left in the MDI Plus was significantly lower than within the AeroChamber Plus (p < 0.05). The amount deposited on the MDI and the hands of the patients after multiple storage in the MDI Plus box and uses was insignificant and within the allowed limits.

Conclusion: The MDI Plus simultaneously can act as an pMDI packaging box and spacer, serving as a practical, affordable, and accessible alternative to traditionally commercially available plastic spacers, particularly in resource-limited settings.