Table 1.

Formulation strategies to overcome removal of drugs via lung clearance mechanisms.

Lung Clearance Mechanism	Strategy	Reference
Mucociliary Clearance	Dae = 1.8–2.8 μm Increase mucus penetration with PEG-based formulation	[20,21,22]
Alveolar Phagocytosis	Dae = 1–1.5 μm Vary particle size: nanoparticles, microparticlesVary geometric shape—worm-like-shaped particles	[23]
Dissolution	Micro and nanoparticles (lipid-, polymer-based) Liposomes	[22,24]