Factors affecting the efficiency of aerosolized salbutamol delivery via a metered dose inhaler and equine spacer device.

The research investigates factors that influence the efficiency of aerosolized salbutamol delivery via metered dose inhalers (MDIs) and spacer devices in horses. The study reveals that under optimal conditions, only a certain portion of salbutamol is delivered beyond the spacer. Also, deviations from the ‘best practice’ delivery technique did not significantly change the relative salbutamol delivery beyond the spacer.

Overview of the Research

• The research explored how efficiently aerosolized salbutamol is delivered using metered dose inhalers (MDIs) and spacers, tools often utilized in treating respiratory diseases in equine practice. Salbutamol is a bronchodilator used to treat conditions such as asthma in horses and humans.
• The authors were driven to conduct this study due to the lack of substantial data on the effectiveness of aerosol delivery using MDIs and equine spacers, especially considering their widespread use.

Methodology of the Research

• The study examined the particle size distribution within an MDI-generated salbutamol aerosol delivered through an equine spacer, following the ‘best practice’ delivery technique.
• The researchers evaluated the impact of various ways of using the MDI (such as shaking the inhaler before each use, rapid repetitive usage, and changing the angle of the MDI) on the efficiency of salbutamol aerosol delivery.

Key Findings of the Research

• It was found that under the best circumstances, only 53(±18) µg of salbutamol per 100 µg actuation was delivered beyond the spacer.
• Although the aerosol had a high amount of tiny particles (<5 µm) and low mass median aerodynamic diameter, there was a significant variance (31-79%) of the quantity of salbutamol delivered in different experimental runs. This variability makes it challenging to predict the amount of drug delivered to the patient during equine inhalation therapy.
• In spite of observable trends and minor statistically significant changes in the least abundant particle sizes, none of the variations from the ‘best practice’ delivery technique significantly altered the salbutamol delivery beyond the spacer. This finding implies that slight deviations from the recommended aerosol delivery procedure may not significantly impact drug delivery, which could be relevant for maintaining user compliance.