Method and apparatus for filling containers

A method of introducing into a container a suspension or solution of a substance, in particular a pharmaceutical substance, in a propellant under pressure, comprising the steps of:

• providing a container comprising a body defining a storage chamber and a valve stem extending from the body;
• communicating the valve stem of the container with a first outlet opening of a passageway in a main body of a filling apparatus, the filling apparatus comprising a fill actuator comprising a filling valve assembly for selectively introducing into an inlet opening of the passageway propellant under pressure containing a substance in a suspension or solution and an exhaust actuator comprising an exhaust valve assembly for selectively exhausting propellant under pressure containing substance from a second outlet opening of the passageway and including at least one exhaust gas conduit having an outlet opening configured so as, in use, to provide a flow of exhaust gas substantially aligned with a flow of propellant containing substance from the second outlet opening of the passageway;
• opening the filling valve assembly thereby to fill the storage chamber of the container with propellant under pressure containing a substance in a suspension or solution;
• closing the filling valve assembly;
• providing exhaust gas through the at least one exhaust gas conduit;
• and opening the exhaust valve assembly to enable propellant under pressure containing substance in the passageway and the valve stem of the container to exhaust, whereby the exhausted propellant containing substance is entrained in the exhaust gas.