Optimized aerosol delivery to a mechanically ventilated rodent

Area of Science:

• Biomedical Engineering
• Pharmacology
• Respiratory Physiology

Background:

• Aerosol delivery in mechanically ventilated small animals is complex, influenced by various factors.
• Existing literature reports low lung deposition rates in rodents, necessitating optimization.
• This study focuses on improving aerosol delivery to in vitro and in vivo rodent models.

Purpose of the Study:

• To optimize aerosol delivery systems for mechanically ventilated rodents.
• To enhance inhaled mass and lung deposition rates.
• To evaluate the impact of a drug recycling step on aerosol delivery.

Main Methods:

• Utilized gravimetric analysis, laser diffraction, and spectrophotometry for in vitro characterization.
• Optimized an aerosol delivery setup for mechanically ventilated rats.
• Employed a tracer aerosol (Evans blue) for in vivo deposition studies.

Main Results:

• Droplet size, ventilation, breath actuation, and a recycling step significantly affected inhaled mass.
• The addition of a recycling step improved inhaled mass by up to 41%.
• Achieved in vitro deposition rates of 29.95% and in vivo deposition rates of 30.88% for tracer aerosols.

Conclusions:

• The optimized setup achieved higher inhaled mass compared to previous reports.
• A recycling step shows potential for increasing deposition in mechanically ventilated lungs.
• Further assessment is needed for the suitability of test agents for repeated nebulization.