Auto-injector with filling means

An injection device comprises a housing adapted to receive a fluid container having a discharge nozzle and a dispensing piston moveable in the fluid container to expel the contents of the fluid container out of the discharge nozzle. A drive is adapted on activation to act on the fluid container to advance it from a retracted position in which the discharge nozzle is contained within the housing to an extended position in which the discharge nozzle extends from the housing and act on the dispensing piston to expel the contents of the fluid container out of the discharge nozzle. A connector is adapted to receive a vial containing fluid and connect it to the discharge nozzle. There is also means to move the dispensing piston relative to the fluid container from a first position in which the dispensing piston is located in the fluid container adjacent the discharge nozzle to a second position in which the dispensing piston has been drawn away from the discharge nozzle, thereby drawing fluid from the vial into the fluid container.

FIELD OF THE INVENTION

The present invention relates to an injection device for use with a vial.

BACKGROUND OF THE INVENTION

Subcutaneous drugs can be supplied to patients in a vial for home injection. The current method is for the patient to draw the drug from the vial into a syringe and perform a manual injection. The market is moving towards auto-injectors to carry out home injection. Auto-injectors which are manufactured and assembled including a pre-filled syringe of drug are known, for example from international patent application publication no. 2006/106295, which is incorporated herein by reference. There is currently no easy way for a patient to transfer a subcutaneous drug from a vial into an auto-injector.

SUMMARY OF THE INVENTION

The present invention aims to solve the aforementioned problems.

In a first aspect of the invention, there is provided an injection device comprising:a housing adapted to receive a fluid container having a discharge nozzle and a dispensing piston moveable in the fluid container to expel the contents of the fluid container out of the discharge nozzle;a drive adapted on activation to act on the fluid container to advance it from a retracted position in which the discharge nozzle is contained within the housing to an extended position in which the discharge nozzle extends from the housing and act on the dispensing piston to expel the contents of the fluid container out of the discharge nozzle;characterised by:a connector adapted to receive a vial containing fluid and connect it to the discharge nozzle; andmeans to move the dispensing piston relative to the fluid container from a first position in which the dispensing piston is located in the fluid container adjacent the discharge nozzle to a second position in which the dispensing piston has been drawn away from the discharge nozzle, thereby drawing fluid from the vial into the fluid container.

The provision of means to move the dispensing piston relative to the fluid container permits the syringe in the injection device to be filled from a standard vial which greatly facilitates home use of the injection device for drugs that are contained in vials.

In one embodiment of the present invention, the injection device comprises a drive sub-assembly including the drive and dispensing piston and a dispensing sub-assembly including the connector and fluid container,wherein the dispensing piston is connected to the drive,wherein the drive sub-assembly and dispensing sub-assembly are adapted to slide relative to each other,wherein the drive sub-assembly and dispensing sub-assembly are arranged such that when they are pulled apart from each other, the dispensing piston moves from its first position into its second position thereby transferring fluid from the vial into the fluid container.

Preferably, the dispensing sub-assembly is adapted to slide, in part, inside the drive sub-assembly.

Preferably, the dispensing sub-assembly and drive sub-assembly are adapted to rotate relative to each other from an unlocked position in which the dispensing sub-assembly can slide relative to the drive sub-assembly to a locked position in which the dispensing sub-assembly cannot slide relative to the dispensing sub-assembly. In order to facilitate this, locking protrusions may be provided on one of the dispensing sub-assembly or drive sub-assembly and corresponding grooves are provided on the other.

In an alternative embodiment of the invention, the moving means comprises a slider located in the housing in communication with the dispensing piston. The slider may comprise a user-actuatable movement element which protrudes from the housing. The slider may be in magnetic communication with the dispensing piston. Alternatively, the slider may be integrally connected to the dispensing piston.

The receiving means may be a removable cap located over the discharge nozzle on the injection device, wherein the cap has an open end which is adapted to receive the vial, wherein the removable cap is adapted such that removal of the cap from the housing detaches the vial from the discharge nozzle. The removable cap may comprise a removable cover element over the open end, wherein the removable cover element is adapted to be removed prior to insertion of a vial into the open end. Preferably, the removable cover element holds a shield which is located over the discharge nozzle when the removable cover element is in place on the removable cap and which becomes removed from the discharge nozzle when the removable cover element is removed from the removable cap.

On insertion of the vial into the connector, the discharge nozzle pierces a closure element of the vial to form a fluid pathway between the vial and the fluid container.

Preferably, the fluid container is a syringe and the discharge nozzle is a needle.

Preferably, the injection device comprises a release mechanism adapted on activation to release the drive to act on the dispensing piston to move the syringe to its extended position and eject fluid via the discharge nozzle.

In one embodiment of the invention, there is provided a retraction mechanism adapted to move the fluid container from its extended position to its retracted position after the contents of the fluid container has been expelled.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2show a delivery device110according to the present invention, having a delivery device housing112with a proximal end110aand a distal end110b. The distal end110aof the housing112has an exit aperture128, through which the end of a sleeve119can emerge.

The delivery device110is assembled from two sub-assemblies as shown inFIG. 1. A delivery sub-assembly210comprises nose portion102, a syringe carrier150, an interchangeable release element155, sleeve119and spring126, as well as an end-cap101. The nose portion102surrounds and supports the syringe carrier150and connects to the101cap by a screw and twist connection.

A drive sub-assembly220comprises the housing112and drive elements and actuators of the injection device110as will be discussed below. Upon assembly of the two sub-assemblies220,210to form the injection device110, the drive assembly220is able to actuate the syringe114held by the delivery sub-assembly210. After actuation, the two sub-assemblies can be separated and the drive elements and actuators of the drive assembly220reset for further use.

The housing112is adapted to receive a hypodermic syringe114of conventional type, including a syringe body116defining a reservoir and terminating at one end in a hypodermic needle118and at the other in a flange120. The syringe body116is of substantially constant diameter along the length of the reservoir, and is of significantly smaller diameter close to the end of the syringe114which terminates in the hypodermic needle. A drive coupling134acts through the bung of the syringe114to discharge the contents of the syringe114through the needle118. This drive coupling134constrains a drug to be administered via a plunger104within the reservoir defined by syringe body and also permits the drug to be loaded into the syringe114. Whilst the syringe114illustrated is of hypodermic type, this need not necessarily be so. Transcutaneous or ballistic dermal and subcutaneous syringes may also be used with the injection device of the present invention.

As illustrated, the syringe114is housed in the syringe carrier150within the delivery sub-assembly210. The syringe carrier150has a proximal end151through which the needle118of the syringe protrudes. The return spring126, via the return spring support160and the syringe carrier150biases the syringe114from an extended position in which the needle118extends from the aperture128in the housing112to a retracted position in which the needle118is contained within the housing112.

The syringe carrier150comprises a sheath (not shown) into which the syringe114can be inserted from a distal end170. The syringe114is provided with a boot101aover the needle118. If the syringe were to fail or break, the sheath, which surrounds the syringe114along its length, would contain the broken pieces of syringe and reduce the likelihood of them from escaping from the injection device110.

The boot101aprotects the needle118and seals it against contamination prior to removal of the boot101a. The boot101ais gripped, after the syringe118has been inserted into delivery sub-assembly210, by cap101, which is removably located on the housing112over the exit aperture128. The boot101ais gripped in cap101by cover element101bwhich is removable from the cap101so that the boot101ais also removed, thereby exposing a port101c, which is an opening formed in an open end of the cap101.

The housing112of the drive assembly220also includes an actuator214, and a drive which here takes the form of a compression drive spring130. Drive from the drive spring130is transmitted via a multi-component drive to the piston of the syringe114to advance the syringe114from its retracted position to its extended position and discharge its contents through the needle118. The drive accomplishes this task by acting directly on the drug and the syringe114. Static friction between the drive coupling134and the syringe body116initially ensures that they advance together, until the return spring126bottoms out or the syringe body116meets some other obstruction (not shown) that retards its motion.

The multi-component drive between the drive spring130and the syringe114consists of three principal components. A drive sleeve131takes drive from the drive spring130and transmits it to a drive element132. This in turn transmits drive to the drive coupling134already mentioned.

The drive element132includes a user-actuatable syringe loading element133which engages with the drive coupling134internally via locking elements133cand extends via a first arm133athrough the drive element132. On assembly, in an unloaded position, a distal end235of the drive coupling134sits against a plunger104within the syringe114at its distal end adjacent the connection to the needle118. The first arm133ais connected at its proximal end to a second arm133bwhich comprises a user-actuable protrusion133d. On assembly, the user-actuatable protrusion133dextends out of the housing via slot190. A further slot (not shown) on the proximal end of the housing112permits the first and second arms133a,133bto extend out of the housing112when the syringe loading element133and plunger104is moved by sliding user-actuatable protrusion133aproximally to a proximal position, adjacent the open end114aof the syringe114. In the loaded position, the drive element132becomes locked to drive coupling134via latching arms132a,134aon the drive element132and drive coupling134. Thus, the drive coupling134can now move with the drive element132and drive sleeve131on release of the drive spring130. In an alternative embodiment of the invention, the syringe loading element133may be connected directly to the plunger through a bore in the first arm133aand the drive coupling134may be in a proximal position at the open end114aof the syringe114. The syringe loading element133is then actuated to slide the plunger104to wards a proximal position at the open end114aof the syringe114adjacent the syringe coupling134.

The actuator214, in the form of a trigger, is provided on the housing112remote from the exit aperture128. The trigger, when operated, serves to decouple the drive sleeve131from the housing112, allowing it to move relative to the housing112under the influence of the drive spring130. The operation of the device is then as follows. The actuator214is prevented from being actuated by sliding sleeve119and sliding sleeve locking element119awhen the sliding sleeve119is in its most distal position extending out of the exit aperture128. When the distal end of the sliding sleeve is placed against tissue or pushed into the exit aperture, the locking element119ano longer acts on the actuator214and the actuator can be actuated.

The actuator is then depressed and the drive spring130is released. The drive spring130moves the drive sleeve131, the drive sleeve131moves the drive element132and the drive element132moves the drive coupling134. The drive coupling134moves and, by virtue of static friction and hydrostatic forces acting through the drug to be administered, moves the syringe body114against the action of the return spring126. The syringe body114moves the syringe carrier150, which in turn moves the return spring support160and compresses the return spring126. The hypodermic needle118emerges from the exit aperture128of the housing112. This continues until the return spring126bottoms out or the syringe body116meets some other obstruction (not shown) that retards its motion. Because the static friction between the drive coupling134and the syringe body116and the hydrostatic forces acting through the drug to be administered are not sufficient to resist the full drive force developed by the drive spring130, at this point the drive coupling134begins to move within the syringe body116and the drug begins to be discharged. Dynamic friction between the drive coupling134and the syringe body116and hydrostatic and hydrodynamic forces now acting through the drug to be administered are, however, sufficient to retain the return spring126in its compressed state, so the hypodermic needle118remains extended.

Before the drive coupling134reaches the end of its travel within the syringe body116, so before the contents of the syringe have fully discharged, flexible latch arms134blinking the first and drive couplings132,134reach an interchangeable release element155connected to the distal end of the syringe carrier150.

The interchangeable release element155is essentially a constriction which moves the flexible latch arms132bto a position so that they no longer couple the drive element132to the drive coupling134. Once this happens, the drive element132acts no longer on the drive coupling134, allowing the drive element132to move relative to the drive coupling134. Consequently, the drive coupling134continues to move within the syringe body116and the drug continues to be discharged. Thus, the return spring126remains compressed and the hypodermic needle remains extended.

After a time, the drive coupling134completes its travel within the syringe body116and can go no further. At this point, the contents of the syringe114are completely discharged and the force exerted by the drive spring130acts to retain the drive coupling134in its terminal position, allowing the drive element132to continue its movement.

Flexible latch arms linking the drive sleeve131with the drive element132reach another constriction within the housing112. The constriction moves the flexible latch arms so that they no longer couple the drive sleeve131to the drive element132. Once this happens, the drive sleeve131acts no longer on the drive element132, allowing them to move relative each other. At this point, the forces developed by the drive spring130are no longer being transmitted to the syringe114. The only force acting on the syringe will be the return force from the return spring126which acts on the end of the syringe114nearest to the needle118via the return spring support160and the syringe carrier150. Consequently, the syringe is returned to its retracted position and the injection cycle is complete.

FIGS. 3ato3dshow one embodiment of the injection device110and the steps by which it is loaded with fluid from a vial300prior to injection. The vial300is of standard size and comprises a closure element301which seals the vial. The closure element301may be in the form of a flexible membrane which can be pierced by the needle118. The port101cin the cap101is sized and dimensioned to receive the vial300and support it whilst fluid is extracted from the vial into syringe114. The process for doing this is as follows.

As shown inFIG. 3b, the closure element101bis removed from the cap101whilst the cap101remains in place on the housing112. This removes the boot101afrom the needle118and opens the port101c, in which the needle118is exposed.

The vial300is inserted into the port101cend first, i.e. the end which includes the closure element301. As the vial300is inserted, the needle pierces the closure element301and extends into the vial300so that its end point resides in the fluid contained within the vial300. Preferably, the injection device110should now be positioned so that its longitudinal axis extends vertically with the vial300located nearest the ground. Gravity acts on the fluid in the vial300to keep it in the bottom of the vial, so that the fluid can be extracted.

The user can now operate the syringe loading element133by sliding the protrusion133dtowards the proximal end of the injection device110. This causes the plunger104in the syringe114to move from its unloaded position towards the proximal end of the syringe114into its loaded position and extract fluid from the vial300into the syringe114via a reduction of pressure in the syringe114. When the syringe loading element133has reached its loaded position, i.e. at the most proximal end of the slot190, the syringe114has been loaded with fluid from the vial300. The vial300can now be removed from the injection device110by removing the cap101so that the injection device110is ready for use, by placing the distal end of the sliding119sleeve against tissue and activating the actuator214.

FIGS. 4ato4dshow an alternative embodiment of the injection device110and the steps by which it is loaded with fluid from a vial400prior to injection. The structure of the injection device110of this alternative embodiment is the same as for the embodiment depicted inFIGS. 1 and 2, except for the differences explained below. As in the embodiment ofFIGS. 3ato3d, the vial400is of standard size and comprises a closure element405which seals the vial400. The closure element405may be in the form of a flexible membrane which can be pierced by the needle118. In this alternative embodiment, the cap401of the delivery sub-assembly210, comprises a cover element401band flange401dat its distal end. The cap401is also connected to nose portion402of the delivery sub-assembly210which is slidable and rotatable into and out of the housing112between an unloaded and loaded position. In its extended loaded position, the nose portion402can be rotated to lock its position relative to the housing112. As in the embodiment described inFIGS. 1 and 2, the nose portion402supports the syringe114which moves with the syringe portion relative to the drive coupling134, which in this alternative embodiment, is fixed to the drive element132. In this alternative embodiment, there is no syringe loading element. A port401cin the cap101is sized and dimensioned to receive the vial400and support it whilst fluid is extracted from the vial into syringe114. The process for doing this is as follows.

As shown inFIG. 4b, the closure element401bis removed from the cap401whilst the cap401remains in place on the housing112. This removes the boot101afrom the needle118and opens the port401c, in which the needle118is exposed.

The vial400is inserted into the port401cend first, i.e. the end which includes the closure element401. As the vial400is inserted, the needle118pierces the closure element401and extends into the vial400so that its end point resides in the fluid contained within the vial400. Preferably, the injection device110should now be positioned so that its longitudinal axis extends vertically with the vial300located nearest the ground. Gravity acts on the fluid in the vial400to keep it in the bottom of the vial, so that the fluid can be extracted.

The user can now slide the delivery sub-assembly210relative to the drive sub-assembly220by, for example, pulling on the flange401dto cause the cap401and nose portion402, including the syringe114, to extend away from the distal end of the drive sub-assembly220. This causes the plunger104, held by the drive coupling134, in the syringe114to move from its unloaded position towards the proximal open end114aof the syringe114into its loaded position and extract fluid from the vial400into the syringe114via a reduction of pressure in the syringe114. When the delivery sub-assembly210is fully extended from the drive sub-assembly220, the cap401and nose portion402can be rotated to lock and prevent further longitudinal movement of the delivery sub-assembly210relative to the drive sub-assembly220. The syringe114has now been loaded with fluid from the vial400. The vial400can now be removed from the injection device110by removing the cap101, for example by further rotation, so that the injection device110is ready for use, by placing the distal end of the sliding119sleeve against tissue and activating the actuator214.

It will of course be understood that the present invention has been described above purely by way of example and modifications of detail can be made within the scope of the invention.