| 摘要 |
<p>A housing defines a passageway having a mouth piece at one end and through which air is inhalable through the passageway, a dispenser being connected to the housing and operable to dispense a metered dose of aerosol liquid or powder. Electrodes (16, 22) are located intermediate the dispenser and the mouth piece and define a charging region (26). A charging circuit (21) applies a voltage across the electrodes, one of which has a pointed feature, such that particles passing through the charging region acquire charge of a predetermined polarity. A breath sensor (51) is used to co-ordinate operation of the charging circuit with the inhalation of the dose. The site of deposition of inhaled particles within the respiratory tract can thereby be influenced by selecting the magnitude and polarity of the voltage applied to the electrodes.</p> |
