Drug delivery from holding chambers with attached facemask

Area of Science:

• Pharmaceutical Sciences
• Pediatric Medicine
• Biomedical Engineering

Background:

• Metered dose inhalers (MDIs) with holding chambers and facemasks are increasingly used for aerosol delivery to infants.
• Optimizing aerosol deposition in infants requires understanding the impact of device design and physiological factors.

Purpose of the Study:

• To investigate how holding chamber design and tidal volumes affect inhaled aerosol dose in infants.
• To evaluate the efficacy of different delivery devices and breathing patterns for pediatric aerosol therapy.

Main Methods:

• A model simulating infant breathing was created using a Starling ventilator.
• Sodium cromoglycate was delivered via Nebuhaler, Aerochamber, and a coffee cup at tidal volumes of 25, 50, and 150 ml.
• Dose deposited after six breaths was quantified using ultraviolet spectrophotometry.

Main Results:

• Smaller chambers enhanced drug delivery at low tidal volumes, while larger chambers were more effective at high tidal volumes.
• Multiple breaths resulted in a relatively large inhaled dose per kilogram, even with significant dead space.
• Increasing the initial dose increased delivered dose, but not proportionally.

Conclusions:

• Holding chamber and facemask devices can deliver substantial aerosol medication to infants.
• Device characteristics and breathing parameters significantly influence aerosol delivery efficiency.
• Optimizing valve design may further enhance aerosol drug delivery in pediatric patients.