Different techniques of aerosol administration to the lower respiratory tract.

Nebulizers, pressurized aerosols and powder aerosols are often used by asthmatic patients in order to obtain an immediate, local effect from a low dose of a drug in the lower respiratory tract. However, the aerosol delivery systems are not ideal for oral inhalation as the availability to the lower respiratory tract is low, the device is not always easy to use in an acute situation, and the constituents in the dosage form may cause side effects. The aerosol delivery systems for clinical practice are described and their limitations are emphasized. It is suggested that controlled comparative studies be performed concerning various systems for oral inhalation.