What is a key characteristic of medications designed for delivery through the lungs?

Medications intended for delivery through the lungs are characterized by a very small particle size. This feature is crucial because it allows the drug to reach the deep regions of the lungs, including the alveoli, where gas exchange occurs. Particles that are too large may get trapped in the upper airways or fail to penetrate deeply enough into the respiratory tract to achieve the desired therapeutic effect.

Moreover, smaller particles enhance the medication's ability to diffuse into the bloodstream through the alveolar walls, which leads to rapid absorption and onset of action. This is particularly important for medications used in conditions like asthma and chronic obstructive pulmonary disease, where quick relief of symptoms is often necessary.

Other characteristics of inhaled medications may vary, but the small particle size is essential for effective pulmonary drug delivery and is a distinguishing feature of inhalation therapies.