A pharmaceutical component-mixing delivery assembly comprising: a first cartridge and a second cartridge; the first and second cartridges (2 and 3) being dimensioned so that they are movable relative to one another such that the first cartridge is slidable within the second cartridge from a pre-mixed position to a post-mixed position; the first cartridge comprising a body provided with an outlet end, the first cartridge being fitted with a plunger and containing a first pharmaceutical component; the second cartridge comprising a body provided with an inlet end and an outlet end, the second cartridge comprising an aseptic mixing chamber and containing a second pharmaceutical component; wherein the first cartridge and the second cartridge are separated by a valve component comprising a piston so that as the plunger is depressed, the piston moves towards the inlet of the second cartridge and the mixing chamber expands longitudinally and characterised in that the valve component is a non-invasive valve component and the piston is provided with a terminal rib, comprising a circumferential rib located at the end of the piston nearest to the inlet end of the second cartridge for providing a seal between the side wall of the piston and the inner wall of the second cartridge; and wherein the inner wall of the second cartridge, outside of the mixing chamber and beyond the terminal rib of the piston, is non-aseptic; the non-invasive valve component is generally elongated, the length of which is chosen so as to ensure that, as the mixing chamber expands longitudinally, the pharmaceutical components (7 and 11) never come into contact with the non-aseptic wall of the second cartridge. a first cartridge and a second cartridge; the first and second cartridges (2 and 3) being dimensioned so that they are movable relative to one another such that the first cartridge is slidable within the second cartridge from a pre-mixed position to a post-mixed position; the first cartridge comprising a body provided with an outlet end, the first cartridge being fitted with a plunger and containing a first pharmaceutical component; the second cartridge comprising a body provided with an inlet end and an outlet end, the second cartridge comprising an aseptic mixing chamber and containing a second pharmaceutical component; wherein the first cartridge and the second cartridge are separated by a valve component comprising a piston so that as the plunger is depressed, the piston moves towards the inlet of the second cartridge and the mixing chamber expands longitudinally and characterised in that the valve component is a non-invasive valve component and the piston is provided with a terminal rib, comprising a circumferential rib located at the end of the piston nearest to the inlet end of the second cartridge for providing a seal between the side wall of the piston and the inner wall of the second cartridge; and wherein the inner wall of the second cartridge, outside of the mixing chamber and beyond the terminal rib of the piston, is non-aseptic; the non-invasive valve component is generally elongated, the length of which is chosen so as to ensure that, as the mixing chamber expands longitudinally, the pharmaceutical components (7 and 11) never come into contact with the non-aseptic wall of the second cartridge.