Dry powder inhalers: Particle size and patient-satisfaction

Inhalational route is the cornerstone for drug delivery in asthma. Dry powder inhalers efficiently deliver drug particles to lungs depending on patients' breath actuation and without using propellants. Drug delivery in lungs is dependent primarily on particle size distribution of the formulation. Several studies have proved that drug particles 1-3 mu m in size provide optimum efficacy with minimum adverse events. Particles >3 mu m are deposited in the oropharynx and those <1 mu m are exhaled. However, these fine particles might not be felt in the mouth due to which patients may feel that appropriate amount of drug was not dispensed. This perception may negatively influence patient satisfaction and confidence on the device. The patient education on the absence of mouthfeel is thus essential. Treating physicians should provide optimum patient counseling and education addressing the importance of particle size for desired clinical effects.