PRE-FILLED RETRACTABLE NEEDLE INJECTION DEVICES

摘要

A pre-filled injection device having a retractable needle (25) with a sharpened tip for penetrating the skin of a patient for administering medicinal fluids is provided. The pre-filled injection device of the present invention allows the needle to be manually retracted, thereby reducing the risk of transmission of various pathogens, most notably human immune virus (HIV), to uninfected personnel, due to an inadvertent prick. The present prefilled injection device has a hollow housing (7) which receives a pre-filled cartridge (1) containing medicinal fluids. A needle retainer (22) initially holds a needle (25) projecting forward from the hollowing housing (7). The rear end (27) of the needle (25) pierces the pre-filled cartridge (1) when sufficient pressure is applied to the end (27) of the pre-filled cartridge (1) to advance it in the forward direction. A plunger (35) is slidably displaceable within the hollow housing (7). A latch member (72) is operable in a latched position to prevent forward movement of the plunger (35). The latch member is operable in an unlatched position to permit forward movement of the plunger (35) and retract the needle (25) into the hollow housing.