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 (138) comprising a body (139) defining a storage chamber (140) and a valve stem (144) extending from a head (141) of the body (139), the valve stem (144) having an outlet opening (147) and a lateral inlet opening (148) and being movable between an extended closed position in which the lateral inlet opening (148) is located outside the body (139) and a depressed open position in which the lateral inlet opening (148) is located within the body (139);
• communicating the outlet opening (147) of the valve stem (144) with a passageway (20) in a main body (4) of a filling apparatus (2), the filling apparatus (2) comprising a fill actuator (7) comprising a filling valve assembly (29) for selectively introducing into the passageway (20) propellant under pressure containing a substance in a suspension or solution and an exhaust actuator (10) comprising an exhaust valve assembly (48) for selectively exhausting propellant under pressure containing substance from the passageway (20);
• opening the filling valve assembly (29) thereby to fill the storage chamber (140) of the container (138) with propellant under pressure containing a substance in a suspension or solution;
• closing the filling valve assembly (29);
• opening the exhaust valve assembly (48) to enable propellant under pressure containing substance in the passageway (20) and the valve stem (144) of the container (138) to exhaust;
• and
• surrounding the part of the valve stem (144) of the container (138) which includes the lateral inlet opening (148) and extends from the body (139) of the container (138) with a pressurised fluid at least when the exhaust valve assembly (48) is opened to exhaust propellant under pressure containing substance from the passageway (20) and the valve stem (144) of the container (138).