The present invention relates to a single-use syringe comprising a barrel (10) having an internal surface defining a chamber for retaining a fluid, a plunger (1) formed by an elongated body including a plurality of longitudinal fins (2) and optionally a piston (3) connected to the end of the plunger close to the needle, the external surface of the piston or of the end of the plunger in the case of not including a piston being in leak-tight connection with the internal surface of the barrel, where the barrel has a general external shape of a cylinder of revolution with a constant radius circular base and a variable internal shape, forming the wall of the barrel with variable thickness, generating a chamber inside which a plunger incorporating a plurality of fins (2) slides; each of the longitudinal fins (2) of the plunger has a constant height along its entire length but different from that of at least one of the other fins, which height is suitable in each fin so that the plunger (1) can be inserted tightly without the capability of rotating about itself through the space defined by the variable internal radius of the barrel; the length of at least one of the fins is also different from the length of at least one of the other fins so that the plunger includes a weakened area in the form of a hole at the end of the plunger close to the needle; the barrel further comprises at least two grooves in the internal face of the barrel, at least one being located in the distal part (8) and at least one in the proximal part (9) of the barrel with respect to the needle.

Disclosed is a self-destructing syringe, comprising an outer casing, a core bar, a piston, a conical head component, a syringe needle and a protecting jacket. The syringe needle is fixed in the conical head component, and the conical head component consists of a threaded conical head, a sealing ring, a transition part and a hollow wedge. The protecting jacket is put around the syringe needle and is movably connected to the needle base of the syringe needle; the conical head component is fixed in the inner cavity at the front end of the outer casing; the piston is installed on the core bar; the main part of the core bar is sheathed inside the outer casing; and the front end of the core bar is inserted into the conical head component and is able to make the syringe needle return inside the outer casing.

A feedback mechanism (300) for a medicament delivery device, the feedback mechanism (300) comprising a feedback portion (30) and a plunger rod (12): wherein the plunger rod (12) comprises an engagement structure (121): wherein the feedback portion (30) comprises one or more attachment parts (32); wherein the one or more attachment parts (32) are configured to connect the feedback portion (30) to another part of the medicament delivery device: wherein the feedback portion (30) is configured to engage with the engagement structure (121) during use of the medicament delivery device so that the one or more attachment parts (32) detach or break during movement of the plunger rod (12) relative to the feedback portion (30).

One embodiment is directed to a system for injecting, comprising a syringe body defining an interior medicine chamber; a stopper member configured to be inserted into the interior medicine chamber to contain medicine within the medicine chamber; a plunger member configured to be manually manipulated to insert the stopper member relative to the syringe body; and a needle having proximal and distal ends, the proximal end comprising an anchoring geometry configured to be at least partially inserted into the stopper member such that upon retraction of the stopper member, the needle is pulled proximally along with the stopper to be at least partially contained within the interior medicine chamber.

A safety syringe (100; 700; 1200) comprising: a barrel (104; 704; 1204) having an opening at an end thereof; a syringe plunger (108; 708; 1208) configured to move within the barrel such that an inward stroke of the syringe plunger causes a substance within the barrel to be expelled from the opening; and a sheath (112; 712; 1212) configured to cover at least partially the opening in the barrel after use of the syringe, wherein the safety plunger is decoupled from the sheath and is configured to couple to the sheath at a first point on the inward stroke and to decouple from the syringe plunger at a second point on the inward stroke such that the sheath is moveable independently of the syringe plunger and further movement of the sheath after decoupling at least partially covers the opening in the barrel.

A system for injection includes a disposable portion and a reusable portion. The disposable portion includes a syringe body having proximal and distal ends, a syringe interior, and a disposable portion flange at the proximal end thereof, an injectable fluid disposed in the syringe interior, a stopper member disposed in the syringe interior, and a plunger member coupled to the stopper member, wherein the plunger member defines a rack gear including a plurality of rack gear teeth. The reusable portion is configured to be removably coupled to the disposable portion. The reusable portion includes a gear assembly including a pinion gear configured to sequentially advance the plunger member distally by a predetermined distance, and a finger flange coupled to the disposable portion flange.