Abstract: A syringe, for use in the delivery of a dose of a therapeutic agent entrained within a pressurized fluid flow, includes an upstream portion, an intermediate portion, a downstream portion, and an actuator mechanism for initiating a flow of the fluid through the syringe. The upstream portion is interfaced with a source of fluid under pressure. The intermediate portion, which is interposed between the upstream and downstream portions, includes first and second members that are coupled together to provide a closed pocket for containing the dose. One of the first and second members is moveable relative to the other within the syringe to provide an open configuration in which the pocket is opened to expose the dose for entrainment by the fluid as it flows through the intermediate portion and to and through the nozzle. Also provided is a capsule formed from the first and second members.