Patent ID: 6277097
Filing Date: 2001-08-21
Classification: A61J,A61M

Abstract:
An injection system for use in preparing a mixture of a solvent and a medicament and for subsequent dosed injection of the mixture, the system comprising a syringe having a housing with proximal and distal ends, and a replaceable ampoule secured relative to the syringe housing, wherein the ampoule includes a first end closed by a pierceable membrane, a second end closed by a piston having a first coupling element, and a solvent stored between the membrane and piston; and wherein the syringe comprises:means located at the distal end of the housing for mounting a disposable needle;a piston rod which is supported in the housing for axial movement and which includes a second coupling element which detachably couples the piston rod to the piston, such that the piston follows movement of the piston rod in both axial directions;a dose setting and injection mechanism supported by the housing for setting doses and for advancing the piston rod in a distal direction to inject a set dose;a disengageable coupling between the housing and the piston rod to allow movement of the piston rod in the distal direction by means of the dose setting and injection mechanism to eject solvent from the ampoule to mix with a medicament, but to prevent movement of the piston rod in a proximal direction, when an ampoule is secured to the syringe; anda release mechanism which can be activated for selectively releasing the disengageable coupling between the piston rod and the housing while an ampoule is secured to the syringe to allow the piston rod to move in the proximal direction to suck back a mixture into the ampoule, and deactivated to re-engage the disengageable coupling to make movement of the piston rod depend on the dose setting and injection mechanism to prepare the system for injecting such mixture.