A method and system for optimizing the dispensing of aerosol medicaments by “pulsing” a total dose volume as a series of shorter, low volume bursts is described. Aerosol performance when metering at a low volume e.g. <；10 μL is enhanced by an increase in the fine particle fraction, particularly when pulsing a dose to achieve a high total dose volume. By utilising a solenoid valve, the system can deliver a medicament in a single low volume pulse； or in multiple low volume pulses. Performance can be tailored to obtain a preferred fine particle dose and fraction. By manipulating the solenoid valve timings, a single formulation with a concentration X may be used to provide a range of doses. A minimum interval between pulses to achieve separate “non-interacting” plumes which allow keeping total inhalation time comparable to a conventional single dose MDI actuation is also described.
