Lungs are highly specialised organs in charge of gas exchange between the environment and the bloodstream. To obtain the necessary oxygen, lungs take more than 10000 L of air every day that come into close contact with around 6000L of blood through a very extensive and thin air-blood barrier. These features convert the respiratory system in a promising route for administering therapeutic molecules to the body. Delivering drugs to the distal airways could serve to treat both local and systemic diseases. However, evolution has developed various strategies to protect this enormous surface area from the entrance of external particles and their possible injuries. These barriers are multiple and should be considered when intending to administer inhalable therapies. A proper design of the drug and the delivery system could make the difference between reaching or not the alveoli. In this line, pulmonary surfactant has been proposed as a potent drug carrier to overcome lung barriers and enhance the biomedical application of different therapies…