Administration of retinoids by inhalation is used to overcome the chronic
toxicity problems presented by systemic administration and to make
retinoid therapy available as an option for the treatment of fibrotic lung
disease, emphysema, and the prevention and treatment of epithelial cancers
of the respiratory tract, especially those that are associated with
tobacco use. Retinoids are administered by inhalation to the respiratory
tract of the individual as an air-borne composition with a metered dose
aerosol-producing inhaler, in which the retinoid is dissolved in a
combination of a pharmaceutically acceptable chlorofluorocarbon propellant
and an alkylamine solubilizing agent.