EP2092947A1 — Single-use needle-less injection apparatus

USPTO Abstract

A cartridge and nozzle assembly for use in a needle-less injection device, comprising: a drug injection cartridge (14 having a bore (36) and a piston member (50) having a first position cooperating with the bore (36) to define a variable-volume chamber (52) of a first selected size and having a second position to define a variable-volume chamber (52) of a second selected size. The cartridge has an injection nozzle for receiving the cartridge (14), wherein the cartridge (14) includes a flow path communicating an outlet orifice (36b) of the bore (36) to an injection orifice (18) of the injection nozzle; and a displaceable plug member (44), wherein the second selected size of the variable-volume chamber (52) is sufficiently smaller than the first selected size such that when the piston member (50) is moved from the first position to the second position, the plug member (44) is hydraulically forced from a first position of sealing disposition in the flow path to a second position of capture in the flow path, thereby defining an open flow path between the variable-volume chamber (52) and the injection nozzle. The injection nozzle defines a rearward, cartridge-receiving portion and includes a forward portion defining a plug capture chamber (46) with a plurality of bypass passages, the forward portion being configured to receive the plug member (44) when the plug member (44) is displaced to a forwardly disposed position, so that when the plug member (44) is displaced from the bore into the plug capture chamber (46) of the nozzle the inner portion of the cartridge (14) has fluid access to the injection orifice (18) via the bypass passages.