An injector apparatus is disclosed for use with a container of therapeutic material to deliver a metered dose of therapeutic material therefrom. The apparatus includes a first body portion arranged to be fixed relative to the container and defining a first conduit portion for the delivery of the therapeutic material from the container and a second body slidably connected to the first body and defining a second conduit portion, in fluid communication with the first conduit portion. Relative sliding motion between the first body and second body results in the displacement of one of the conduit portions into the other conduit portion such that the combined volume of the conduit may be decreased.
