A prefilled ready-to-use syringe, including a tubular body having, at its distal end, a tip to take a needle and, at its proximal end, a flange, a piston able to slide inside the tubular body and defining, with the tubular body, an internal working volume at least partially filled with a liquid, a rod for actuating the piston extending beyond the proximal end of the tubular body, characterized in that a rigid cover is attached and fixed in a definitive way to the flange and has a central opening for the free translational passage of the actuating rod, and the said cover forms a stop for the actuating rod in the proximal direction, and a plug is arranged to translate freely in the tubular body between the piston and the proximal end of the body, the plug being resistant to puncturing with a needle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. 371 of International Application No. PCT/FR04/01294, filed May 25,2004, which claims priority from French Patent Application No. 03/06334 filed May 26, 2003each of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a device for medical use, of the prefilled syringe type comprising a piston, the said device comprising means for preventing access to the piston and its withdrawal once the said device has been filled with a medicinal liquid for example.

BACKGROUND OF THE INVENTION

In the field of prefilled ready-to-use syringes, devices have already been described that make it possible to determine whether or not the syringe has already been used. These devices generally relate to the distal end of the syringe, that is to say to the needle end of the syringe. Thus it has been proposed for the needle to be covered with a cap that has to be broken before the syringe can be used.

However, in the case of prefilled syringes, it is useful to provide a device preventing access to the piston. It is also useful to provide a device preventing the piston from being withdrawn. This is because it can happen that the actuating rod that actuates the piston is removed and the piston is then punctured with a needle to inject into the syringe a liquid or component that is unforeseen or unauthorized. The rod is then refitted to the piston.

During the process of manufacture of this type of syringe, the syringes are filled in a sterile environment then packaged and possibly sterilized. It is between these two steps of filling and packaging that the internal chamber of these syringes must not be exposed or that the drug it contains must not be contaminated.

Document EP 0 738 517 describes an open clip that is slipped, while the piston actuating rod is already mounted, over the flange situated on the proximal part of the body of the syringe so as to prevent movement and/or withdrawal of the syringe piston. However, this clip, because it is open, can easily be removed and then reinstated on the flange of the syringe. It cannot therefore be used to deny access to the piston. Nor does it prevent withdrawal of the piston.

Other systems said to be “closed” exist, but the withdrawal of the piston is prevented only when the piston actuating rod is present.

SUMMARY OF THE INVENTION

The present invention aims to remedy this problem by proposing a prefilled syringe equipped with a means making it possible both to prevent access to the piston and to prevent the piston from being withdrawn.

The present invention relates to a device for medical use, of the prefilled ready-to-use syringe type, comprising a tubular body comprising, at its distal end, a tip to take a needle and, at its proximal end, a flange, a piston able to slide inside the tubular body and arranged in an initial position defining, with the tubular body, an internal working volume at least partially filled with a medicinal liquid, a rod for actuating the piston extending beyond the proximal end of the tubular body, characterized in that a rigid cover is attached and fixed in a definitive way to the flange and has a central opening for the free translational passage of the actuating rod, and the said cover forms or comprises means of stopping the actuating rod in the proximal direction, and in that a plug is arranged to translate freely in the tubular body between the piston and the proximal end of the said body, said plug being made of a material resistant to puncturing with a needle.

The device according to the invention denies access to the piston and prevents the piston from being withdrawn. Indeed, in the device according to the invention, if any attempt is made at accessing the piston, an attempt is made to withdraw the actuating rod but, because of the shape of the central opening of the rigid cover which forms a means of stopping the actuating rod in the proximal direction, the actuating rod is halted by this rigid cover and the piston cannot be withdrawn. Furthermore, because of the presence of a stopper made of a material resistant to puncturing with a needle, access to the piston is impossible.

In this application, the distal end of a component is to be understood as meaning the end furthest from the user of the device and the proximal end is to be understood as meaning the end closest to the user of the device.

The plug is arranged to translate freely in the tubular body between the piston and the proximal end of the said body. In an embodiment of the invention, the actuating rod is fixed at its distal end to the plug. In another embodiment of the invention, the actuating rod is not fixed to the plug.

Advantageously, there is a bearing interface between the plug and the piston.

In one preferred embodiment of the invention, a means of stopping in the proximal direction is fixed to the actuating rod between the cover and the plug. The distal end of the actuating rod can be secured to the piston, for instance via the plug.

Advantageously, the plug and the piston are fixed in terms of translation, one on the other.

In one embodiment of the invention, the cover is made of aluminium and is crimped to the flange of the device.

In another embodiment of the invention, the cover is made of stainless steel and clipped in a definitive way to the flange.

In another embodiment of the invention, the cover is made of plastic.

In one embodiment of the invention, the cover is in the form of two halves of a ring, these being rigid and snap-fastened to one another, the two halves of the ring being able to be fixed to the flange, trapping it, each half if a ring comprising a lower platform comprising a semicircular opening corresponding to the external dimensions of the tubular body, and an upper platform comprising a semicircular opening designed for the passage of the actuating rod such that it is free in translational movement.

In one embodiment of the invention, the two halves of the ring are symmetric.

Advantageously, the means of snap-fastening one half of the ring into the other are situated inside each ring half. As a preference, the ring that results from the snap-fastening one inside the other of the two ring halves has on its exterior surface no snap-fastening or disengagement means.

The plug is made of a material resistant to puncturing with a needle. As a preference, the thickness and the nature of the material of the plug are chosen so that the plug cannot be punctured with a needle. As a preference, the material of which the plug is made is chosen from plastics, polyolefin polymers, polycarbonates and blends thereof.

Advantageously, the plug is connected to the distal end of the actuating rod by screwing or snap-fastening of the said rod into the plug.

In one embodiment of the invention, the plug is not secured to the piston.

In another embodiment of the invention, the plug is connected to the piston by screwing of the said plug into the piston.

In one embodiment of the invention, the actuating rod is equipped with at least one projection directed in a plane roughly radial with respect to the axis of the actuating rod, this projection being situated between the plug and the proximal end-of the tubular body.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1depicts a device1comprising a tubular body2made of glass and a piston3able to slide inside the tubular body. The tubular body2has, at its distal end4, a tip5to take a needle, for example a hollow hypodermic needle (not depicted), this tip being closed by a cap6, and, at its proximal end12, a flange13.

The lower end7of the piston defines inside the tubular body2an internal working volume8filled with a medicinal liquid9. A plug14, separate from the piston3, is fixed to the distal end36of an actuating rod11protruding from the proximal end12of the tubular body2. In a not depicted embodiment of the invention, the actuating rod11is not fixed to the plug14. This plug14is arranged so that it is free to move in translation inside the body2, on the proximal side of the said piston3, bearing against the latter in the distal direction. There is therefore a bearing interface10between the plug14and the piston3.

A rigid aluminium cover15is crimped onto the flange13and has a central opening23for the passage of the actuating rod11such that it is free in translation in the proximal direction.

Thus, during the process of manufacture of the device depicted inFIG. 1, if somebody attempts to withdraw the rod11that actuates the piston3from the tubular body after the step of filling the tubular body2but before the device is packaged, this will bring the plug14into contact with the rigid cover15. This cover halts the plug14of the actuating rod11and therefore the actuating rod11itself. Thus, even if the actuating rod11is fully withdrawn from the tubular body2, separating it from the plug14, the latter remains inside the tubular body2and prevents subsequent access to the piston3. Because of the presence of the plug14, it is not possible to puncture the piston3by introducing a sharp means through the opening23.

FIG. 2depicts another alternative form of a device according to the invention. The references that denote the same elements inFIGS. 1 and 2are repeated. The actuating rod11is equipped with radial projections16situated facing each other on that part of the actuating rod that lies inside the tubular body2. These projections16forming stop means can collaborate with the cover15to prevent the piston3from being moved towards the proximal end12of the tubular body beyond a predetermined limit.

According to this second alternative form of the invention, the cover15is made of stainless steel and is clipped in a definitive way onto the flange13using an annular collar17. The cover15further comprises radial tabs18extending into the central opening23and capable of halting the translational movement, in the proximal direction, of the projections16.

FIG. 3depicts an actuating rod11screwed using a screw or threaded part19into the plug14. The piston3is not connected to the plug14. According to this first alternative form of the invention, it is therefore not possible for the user to move the piston3towards the proximal end of the tubular body2of the syringe. Nor is it possible to access the piston3, even if the actuating rod11is unscrewed, because of the presence of the plug14between the cover15and the piston3.

FIG. 4depicts an actuating rod11fixed and clipped into the plug14. According to this second alternative form of the invention, the plug14is screwed onto the piston3using a screw or threaded part20. Thus, the distal end of the actuating rod11is secured to the piston3via the plug14.

FIG. 5depicts a cover15comprising a first half211of a ring21fixed to the flange13of the syringe and a second half212of a ring21ready to be clipped into the said first ring half211.

As can be seen inFIG. 6, the half211of the ring21comprises a lower platform22comprising a semicircular opening24corresponding to the external dimensions of the tubular body2. This half211of the ring21also comprises an upper platform25comprising a semicircular opening26the dimensions of which allow the actuating rod11to pass such that it is free in translational movement. This upper platform25comprises a top face27and a bottom face28.

As is apparent fromFIGS. 6 and 7, each half211or212of the ring21comprises, situated between its bottom platform22and its top platform25, two distinct recesses29and30and, on the other side, two distinct studs31and32. The stud31of a first half211of a ring21has a cutout33able to clip into a cutout34of the recess29of the second half212of the ring21. The stud32of a first half211of the ring21is able to clip into the recess30of the second half212of the ring21.

Each half211or212of the ring21also comprises two blocks35allowing the bottom platform22to be adjusted to suit the external dimensions of the tubular body2so as not to compromise the grip of the ring on the syringe.

FIG. 8depicts the cover15ofFIGS. 5 to 7for which the two halves211and212of the ring21are clipped permanently together, around the tubular body2and on each side of the flange13. Once the cover15is fixed permanently on the tubular body2, it is impossible to access the interior of the said body without destroying this cover.

The present invention is not restricted to the embodiments described by way of example in this patent application.