Table 2.

Summary of Asthma Treatment Delivery Systems.

Class of Delivery System	Delivery Method	Subtypes	Pros	Cons	Clinical Studies (Representative)
Propellant-Pressurized Metered Dose Inhalers (pMDI)	-Aerosolization via liquid propellant under pressure -Inhale deeply upon release	-Press-and-inhale -Velocity- modified -Breath-coordinated -Breath-actuated	-Precise and instant delivery -Waterproof -Pressure delivery	-Requires training -May be altitude sensitive -Tank can rupture -Spacer may be needed	NCT02091986 NCT01136382 NCT00746330 NCT01070524 NCT01803087
Dry Powder Inhalers (DPI)	-Metered dispensing -Deep inhale -Breath hold	-Spring-loaded -Multi-dose	-Simple -Refillable -Rapid action -Easy to formulate	-Particle size is not ultrafine -Vulnerable to humidity and electrostatic influence	NCT03478657 NCT02794480 NCT02753712 NCT01191424 NCT02022761
Nebulizers	-Aerosolization of liquid -Normal breathing	-Piezo-electric membrane -Bernoulli gas pressure differential -Ultrafine mesh	-Uses normal breathing pattern -Can mix drugs easily -Can fine tune particle size	-Bulky -Requires continuous pressure or electricity -Extended treatment time	NCT01951378 NCT01045174 NCT01649401 NCT03029156 NCT02774941