Patent attributes
According to the invention, an auto-injector for administering a dose of a liquid medicament (M) comprises of a substantially cylindrical housing arranged to contain a pre-filled syringe; a syringe retainer slidably arranged with respect to the housing that mounts a pre-filled syringe with an injection needle, a plunger and a stopper for sealing a syringe barrel of the pre-filled syringe; a coupling shroud slidably arranged within the housing and releasably coupled to the plunger; and a single drive means. Upon release, the single drive means is capable of driving the coupling shroud in the proximal direction (P). The proximal translatory movement of the coupling shroud with respect to the housing, translates the syringe retainer in the proximal direction (P) to expose the injection needle of the pre-filled syringe, depresses the plunger connected to the stopper into the syringe barrel to expel the dose of medicament (M) and advances a needle shroud to a safe position (PS) to surround the injection needle after the medicament (M) has been at least partially delivered. The coupling shroud is decoupled from the plunger at a pre-determined second position (II) defined by an aperture formed into the housing.
