Insulin (INS) therapy played a great role in patients with type 1 and type 2 diabetes to regulate
blood glucose levels. Although hypodermic injection was commonly used for insulin delivery, it
had some disadvantages such as pain, needle phobia and the risk of infection. Therefore, pulmonary
insulin delivery had been developed as an alternative method to overcome the therapeutic challenges in
recent years since pulmonary insulin administration showed great improvements in rapid action and
circumvention of first-pass hepatic metabolism. This review described the most recent developments in
pulmonary insulin administration. Firstly, the structure and physiology of the lung cavity were introduced.
Next, the advantages and disadvantages of pulmonary administration were discussed. Then
some new dosage forms for pulmonary insulin were investigated including carriers based on surfactants
and carriers based on polymers. Finally, innovate insulin inhalers and formulations were also described.