Pulmonary administration 3 Flashcards
is humidity in the lungs higher than the surroundings?
yes
when does condensation water on particle surface occur?
particle moves from ambient into high humidity
thin film on water insol particles
surface solution on water sol particles
does solvent evaporation affect deposition?
yes
what are the other factors affecting deposition?
- chemical composition
- aerosol velocity
- respiratory tract physiology
name a method used to improve deposition?
spacer device
how does a spacer device work?
placed between PMDI and patient
reduces initial droplet velocity
allows the evaporation of the propellant
no need for coordination between actuation and inhalation
for who is a spacer device particularly useful for?
children
how do breath actuated devices work?
-fires at correct point of patients inspiratory cycle
name an example of a breath actuated pMDI device?
Easy-breathe and Autohaler
how does breathing patterns improve deposition, what does increased inhaled volume do?
produces greater peripheral distribution of particles
what does increased inhalation flow rate do?
increases deposition of particles in airways that are larger
what happens with rapid inhalation?
impaction deposition at back of the throat
what happens if you hold your breath after inhalation?
-deposition enhanced by diffusion and sedimentation
what does gamma scintigraphy do?
measures deposition in lungs, stomach and oropharynx
is gamma scintigraphy in vivo or in vitro?
in vivo
