In Vitro Tests for Aerosol Deposition. V: Using Realistic Testing to Estimate Variations in Aerosol Properties at the...

Area of Science:

• Pharmaceutical Sciences
• Inhalation Technology
• Drug Delivery Systems

Background:

• Accurate estimation of aerosol dose and particle size exiting mouth-throat (MT) models is crucial for predicting lung deposition.
• In vitro methods can estimate Total Lung Dose (TLD) and Aerodynamic Particle Size Distribution (APSD) exiting MT models.
• These aerosol characteristics influence the drug's regional distribution within the lungs.

Purpose of the Study:

• To evaluate a general method for simultaneous determination of in vitro Total Lung Dose (TLD) and in vitro Aerodynamic Particle Size Distribution (APSD) of budesonide aerosols.
• To assess these parameters exiting small, medium, and large VCU-MT models under realistic inhalation profiles.
• To establish a reliable in vitro assessment for inhaled drug delivery.

Main Methods:

• A modified next-generation pharmaceutical impactor (NGI) was calibrated at 140 L/min.
• Budesonide aerosols from a Novolizer inhaler were analyzed exiting VCU-MT models across various inhalation profiles.
• The method determined variations in aerosol dose and size exiting the MT models.

Main Results:

• The general method provided TLD values statistically comparable to filter capture methods.
• APSD profiles and mass median aerodynamic diameters (MMAD) at the MT exit were determined as functions of MT model size.
• The study reported TLD values ranging from 6.2 to 103.0 μg and MMAD values from 1.7 to 3.6 μm.

Conclusions:

• The developed method reliably determines TLD and APSD for aerosols entering the trachea.
• Simulating realistic inhalation profiles and using different MT models allows for studying key variables.
• This general method supports improved in vitro assessment of inhaled medications for clinical applications.