A process and a metered dose inhaler comprising: an air actuator comprising at least one inlet of liquefied gas (LG) at least one air outlet at least one first LG expanding volume and at least one second air containing volume the first and second volumes are effectively separated by means of a LG blocking member a container with an LG source said container is in a fluid connection with said LG expanding volume via the at least one LG inlet The air actuator is facilitating a metered dose airflow by allowing the expansion of said LG in said at least one LG expanding volume from its condensed liquid phase to its expanded gas phase. The expansion of said LG facilitates the compression of the air within said at least one air containing volume such that a metered dose LG free air flow is inhalable via at least one air outlet.
