T2 Aerosol Drug Therapy Flashcards
What is aerosol ?
A suspended particle of a substance in a gas
Characteristics of therapeutic aerosol
Output
Particle size
Deposition
Aging
Factors affecting particle size
Substance being nebulizad
Nebulizar design
Aerosol generation method
Environmental conditions
MMAD
Mass median aerodynamic diameter
Upper AW recommended MMAD
5 to 50 um
Lower AW recommended MMAD
2 to 5 um
Parenchyma: alveolar region recommended MMAD
1-3 um
Parenchyma or exhaled recommended MMAD
<0.5 (<0.1) um
Deposition
The action of leaving the gas suspension
Emitted dose
The aerosol generated from the nebulizar
Inhaled dose
The part of the emitted dose that is inhaled
Inhaled mass
The actual amount of drug that is inhaled
Respirable mass
The proportion of the drug mass of proper size to reach lower AW
Key mechanisms of aerosol deposition are
Inertial impaction — large particles >5 um
Gravimetric sedimentation — deposition 1-5 um in central AW
Brownian diffusion— alveoli
Inertial impaction
Occurs when aerosol in motion collides with and are deposited on surface