Autoinjector

Abstract

An autoinjector including: a housing, in which can be mounted a syringe () having a plunger, a barrel and needle () at one end thereof through which medicament can be delivered to an injection site,—a syringe support means () capable of causing said syringe to move along an axial path with respect to said housing; biasing means capable of biasing said syringe support means so that said needle is normally inside said housing; and engagement means () selectively moveable by a user from a first position in which rearward movement of the syringe along said axial path is substantially prevented when said syringe is in an extended position where at least part of said needle is out of the housing, to a second position in which rearward movement of the syringe along said axial path relative to said housing is possible and said biasing means causes said needle to retract inside said housing; wherein said housing includes an outer housing () and said autoinjector further comprises a sleeve () intermediate the syringe support means and said outer housing that is capable of moving the engagement means between said first and second positions by rotating said sleeve about a longitudinal axis of said autoinjector between a first rotational position and a second rotational position; and wherein the sleeve is moveable between said first and second rotational positions by moving said outer housing with respect to the sleeve in a substantially axial direction.