The application disclosure provides a sterically stabilized liposome carrier encapsulating a selected drug for the aerosol delivery of the drug effectual in the treatment of a mammal, a composition containing the sterically stabilized liposome carrier and the selected drug effective for the treatment of airway hypersensitivity and inflammation such as of the lungs of a mammal as an aerosol, and a method of treatment using the composition. The composition disclosed herein provides effective treatment for the longer of a period of time at least twice as long as the selected drug alone or up to at least one week.