Drug delivery from jet nebulisers

Area of Science:

• Respiratory Medicine
• Pharmaceutical Technology
• Aerosol Science

Background:

• Jet nebulisers are crucial for delivering medication to the lower respiratory tract.
• Treatment time and patient acceptability, particularly for young children, are limited by current nebuliser efficiency.
• Optimizing drug delivery rate and particle size is key to improving nebuliser therapy.

Purpose of the Study:

• To investigate the impact of technical factors, specifically driving gas flow (DGF), on drug delivery rate from jet nebulisers.
• To model respiratory patterns with varying tidal volumes to simulate real-world drug deposition.
• To determine optimal operating conditions for maximizing the delivery of respirable particles.

Main Methods:

• A model simulating respiratory patterns using a Starling ventilator and filter was constructed.
• Sodium cromoglycate was nebulised under varied conditions (DGF, tidal volume, concentration).
• Dose deposited on the filter was assayed to quantify drug delivery and particle size distribution (<5 microns).

Main Results:

• Increasing DGF from 4 to 8 L/min significantly increased drug output rate (264%) and the proportion of fine particles (<5 microns) from 26.8% to 70.8%.
• Higher DGF resulted in greater drug delivery to the filter, with a 79% increase at 400 ml tidal volume.
• Lower tidal volumes delivered more drug per mL inhaled, indicating higher efficiency at reduced volumes despite lower overall deposition.

Conclusions:

• Driving gas flow is a critical factor in maximizing the rate and fine particle fraction of nebulised drugs.
• Optimizing DGF and considering tidal volume are essential for efficient aerosol delivery to the lower respiratory tract.
• Findings suggest potential for reduced treatment times and improved therapy acceptance, especially in pediatric populations.