MXPA00002039A - Pre-filled retractable needle injection device - Google Patents

Abstract

A needle-bearing device (9100) for injecting medicinal fluid from a pre-filled cartridge (85) is provided. After use, the needle (15) is retracted into the body (20) of the device (10) to prevent inadvertent contact with the sharpened end of the needle (15). In one embodiment, the invention provides a manually actuated button (65) that effectuates retraction of the needle (15) after use. In another embodiment, retraction is effectuated automatically after the injection is complete.

Description

"DEVICE FOR INJECTING WITH RETRACTABLE NEEDLE, PRELIMINARY" Field of the Invention The present invention relates to pre-filled ampoules, capsules or cartridges for administering injections of medicinal fluids to patients. More specifically, the invention relates to those devices that have a characteristic that the needle is retractable to render the device non-reusable and can be disposed of safely.

Background of the Invention Various types of medical devices employ a needle to pierce a patient's skin for diagnostic or therapeutic purposes. One such device is a cartridge injector. Cartridge injectors use pre-filled cartridges that have a pre-measured dose of medicine. The cartridge injector is used to inject the cartridge doctor to a patient. The manipulation of such medical devices containing needle after the needle is removed from the patient, can result in the transmission of several pathogens, most notably the human immunodeficiency virus (HIV), to uninfected medical personnel due to an accidental needle picket Accordingly, it is desirable to provide a device for injecting medication from a pre-filled cartridge, wherein the injection needle retracts towards the housing of the device after use.

DESCRIPTION OF THE DRAWINGS All the objects of the present invention are hereinafter more fully set forth with reference to the accompanying drawings, wherein: Figure IA is a plan view of a cartridge injector incorporating the aspects of the present invention; Figure IB is a side view of the cartridge injector 15 shown in Figure IA, illustrated without a needle cover; • Figure 1C is a side view of the cartridge injector shown in Figure IB, showing the needle retracted; Figure 2 is a fragmentary, fragmented, cross-sectional view of the cartridge injector illustrated in Figure IB; Figure 3 is an enlarged, cross-sectional view of the injector of the cartridge illustrated in Figure 2, taken along line 3-3; Figure 4 is a cross-sectional view, amplified, the cartridge injector • shown in Figure 2, taken along line 4-4; Figure 5 is a fragmentary, fragmented, cross-sectional view of the cartridge injector shown in Figure 2, illustrating the details of the rear needle seal; Figure 6 is a cross-sectional view 10 of an alternative embodiment of a medical device for use to inject medicament from a cartridge; Figure 7 is a cross-sectional view of the device shown in Figure 6, illustrating a device in a position just before releasing the safety fastener; Figure 8 is a cross-sectional view of the device shown in Figure 7, illustrating the device in a position just after releasing the safety fastener; Figure 9 is a cross-sectional view of the device shown in Figure 6, illustrating the insertion needle in a retracted position; Figure 10 is a fragmentary, fragmented, cross-sectional view of the device illustrated in Figure 7, illustrating the details of the safety fastener in a clamped position; and Figure 11 is a fragmented, amplified view of the device shown in Figure 8 showing the details of the safety fastener in an unclamped position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to the drawings in general, and to Figures 1A-1C specifically, there is shown a cartridge injector 10 with a cartridge 85 pre-filled with medication. The cartridge injector 10 includes a front needle 15 with a pointed tip for inserting the needle into a patient. The front needle 15 is in fluid communication with the medicament in the cartridge 85. By pressing the cartridge 85 towards the cartridge injector 10, the medicament is expelled from the cartridge and towards the patient through the front needle 15. After the medicament is administered to the patient, the front needle 15 retracts towards the body of the cartridge injector by pressing a drive button 65. Referring now to Figure 2, the details of the cartridge injector 10 are illustrated. The cartridge injector 10 includes a hollow body or housing 20 having an internal cavity 22. The housing 20 includes a cylindrical barrel 24. The rear end of the barrel 24 it is open, forming a receptacle 35 to receive the cartridge 85. As is. shown in Figure IA, two laterally extended flanges 48 project outwardly from the barrel 24, transverse to the barrel axis, forming two handles to operate the device. Referring again to FIG. 2, the rear end of the housing 20 tapers in a convergent fashion, forming a tip 26 that is integrally connected to the barrel 24. The forwardmost end of the tip 26 is axially elongated to form a hollow cylindrical tip. The tip 30 has an opening 32 through which the front needle 15 projects out of the body 20, so that the pointed tip of the needle can be inserted into a patient to deliver medication to the patient. As shown in Figure IA, before use, a needle cover 44 closes the portion of the front needle 15 projecting from the housing.

The needle cover 44 snaps onto the tip 26 and is retracted by friction at the interface between the outer circumferential groove 20 on the tip and a corresponding internal circumferential edge on the base of the needle cover.

As shown in Figure 2, the cartridge injector 10 includes two needles: the front needle 15 • to be inserted in the patient; and a back needle 17 for piercing the cartridge 85. A duct 5 50 extends between the front needle 15 and the rear needle 17, - 'so that the needles are in fluid communication. The conduit 50 is a cylindrical tube. The rear end of the conduit 50 is generally open, and the leading end of the conduit w 10 has a cylindrical tip of reduced diameter 54. The orifice of the tip 54 is dimensioned to receive the front needle 15. The front needle 15 is retained fixedly in the hole of the tip of the duct 54, preferably by union. Alternatively, the front needle 15 can be attached to the tip of the duct 54 by interference fit or by molding the front needle at the tip of the duct. The tip of the cylindrical duct 54 is inserted in the hole of the tip of the housing 30, so that the front needle 15 projects from the housing 20. The external surface of the tip of the duct 54 corresponds to the internal hole of the tip 30, so that the tip of the duct is coupled by sliding inside the tip. The intersection of the tip of the conduit 54 and the larger diameter of the conduit 50 forms an outer circumferential flange 50. The flange of the conduit 55 comes into contact with a corresponding annular flange formed inside the tip of the housing 26. The rear end of the conduit 50 is supported by a disk-shaped bushing 70 in barrel 24. Bushing 70 includes an annular rim 72 that projects forward from the hub creating a receptacle for receiving the trailing end of conduit 50. A flexible seal 100 provides a fluid-tight seal between conduit 50 and bushing receptacle 72. Seal 100 is generally cup-shaped and is placed around the trailing end of the conduit. The open end of the cup-shaped seal 100 includes a radially inwardly extending circumferential rim 102 that forms an edge that sits in a groove in the trailing end of the conduit. The seal 100 further includes an orifice sized to receive the rear needle 17, to form a fluid tight seal with the rear needle. As shown in Figure 5, the seal 100 projects towards the conduit 50 around the posterior needle forming a fluid-tight seal between the side of the posterior needle and the conduit orifice. As shown in Figure 2, the end 'forward of the rear needle 17 extends through of the seal 100 and projects towards the conduit hole 50. The rear end of the rear needle 17 extends through and is fixedly connected to a mounting rod 80. The mounting rod 80 has a - ^ internal hole to retain the rear needle. Further, The mounting rod is adapted to be releasably connectable to the cartridge 85. A plurality of axially elongated support rods 78 connects the mounting rod 80 to the bushing 70. As shown in FIG. 4, preferably the rods support 78 are laterally elongated to provide greater torsional rigidity; however, the connecting rods may alternatively be cylindrical. Referring again to Figure 2, the rear end of the housing 35 is generally open, forming a receptacle for receiving the cartridge 85. The cartridge 85 is a generally cylindrical container containing a quantity of medicinal fluid. The rear end of the cartridge 85 is closed, and the front end of the cartridge is sealed with a piston25 or rubber plunger 90. The plunger 90 is generally cylindrical and has a plurality of axially spaced circumferential edges 92, which form a fluid-tight seal between the plunger 90 and the inner surface of the cartridge 85. The front or outer end of the The plunger is configured to cooperate with the mounting rod 80 of the cartridge injector. In the present example, the mounting rod 80 is externally threaded and the plunger 90 has corresponding internal threads 94. The inner end of the plunger 90 adjacent to the medicament includes a cavity 96. In this manner, a pierceable wall is formed in the plunger 90. between the cavity 96 and the base of the internal threads 94. When the cartridge 85 is mounted on the mounting rod 80, the rear needle 17 pierces the wall of the plunger and extends towards the cavity 96 formed inside the plunger. The cavity opens towards the interior of the cartridge 85, so that when the rear needle 17 projects into the cavity 96, the rear needle is in fluid communication with the interior of the cartridge 85, allowing the medicament to flow from the cartridge to the needle later. After the back needle 17 pierces the wall of the plunger, the wall forms a fluid-tight seal between the plunger 90 and the side of the rear needle to prevent the medication from leaking into the housing 20.

The medicament is ejected from the cartridge 85 by moving the cartridge 85 axially forward to # advance the cartridge. The plunger 90 is mounted on the mounting rod 80, so that the plunger 5 remains stationary while the cartridge 85 advances. The plunger 90 is "configured to form a sliding fit with the interior of the cartridge, so that the cartridge" 85 can slide over the plunger to eject the medicament from the cartridge. Additionally, the circumferential edges 10 maintain a fluid-tight seal between the piston and the cartridge, while the cartridge slides over the piston. As the cartridge 85 advances, the medicament in the cartridge flows out of the cartridge and towards the posterior needle 17. From the posterior needle 17, the medicament flows into the duct 50 and then the front needle 15 towards the patient. After the medicament is injected into the patient, the front needle 15 can "retract into the housing 20 as follow. A spring 40 is placed around the conduit 50, diverting the conduit backwards. The forward end of the spring 40 comes into contact with the interior of the tip 26, and the rear end of the The spring comes into contact with a rim or circumferential edge 52 formed around the external surface of the conduit 50. The rim 52 engages a fastener f 60 which is connected to an actuating button 65. The pressure of the actuating button 5 65 it releases the edge 52 of the conduit 50 of the fastener 60, so that the spring 40 pushes the conduit and the attached front needle 15 backwards. When the conduit 50 and the needle 15 are; pushed back, the rear end M of the conduit 50 slides through the receptacle of the bushing 72 and on the rear needle 17. Furthermore, when the pipe 50 retracts backwards, the needle seal 100 also retracts backwards on the rear needle 17 and through the bushing receptacle 72. Therefore, for facilitate retraction, seal 100 forms a sliding fit with the rear needle 17 and the receptacle hub 72. Additionally, the seal 100 seals the internal cavity 22 of the housing 20 of the • communication with the fluid in the rear needle 17 and the conduit 50. The details of the fastener 60 retaining the conduit and the front needle 15 in the extended position are best seen in Figure 3. The fastener 60 has a circular opening 62 which is larger in diameter than the diameter of the edge 52 around the conduit 50. The The opening of the fastener 62 is eccentric with the conduit 50, so that the edge of the conduit 52 interferes with the fastener 60 as shown in Figure 3. By pressing the actuating button 65 downwards, the aperture of the fastener 62 is aligned with the edge of the conduit 52, so that the edge of the conductor can pass through the opening of the fastener, allowing the conduit 50 and the attached needle 15 to retract towards the housing 20. Referring again to Figure 2, the fastener 60 is integrally connected to the drive button 65. The drive button 65 is connected to the hub 70 by means of a cantilevered arm 75, so that the drive button rotates around the hub. Preferably, the cantilevered arm 75 deflects the drive button 65 upwards, so that the fastener 60 is biased upwards towards the clamping position shown in Figure 3. Configured in this manner, the cartridge injector 10 operates as follows. A cartridge 85 containing medicament is inserted into the rear end 35 of the housing and the piston of the cartridge 90 is threaded onto the mounting rod 80. When the piston of the cartridge 90 is threaded onto the mounting rod 80, the rear needle 17 punctures the rear wall of the plunger 90, so that the rear needle is in fluid communication with the medicament in the cartridge 85. The cover of the needle 45 is then removed to expose the pointed tip of the front needle 15. The front needle 15 is inserted into a patient when the cartridge 5 advances relative to the stationary plunger 90 to inject the medicament from the cartridge to the patient. After completing the injection, the operator can press the drive button 65 to release the edge 52 of the fastener 60 that retains the conduit 50. The spring 40 then pushes the duct 50 and the front needle 15 backward until the front needle is completely enclosed within the housing 20 as shown in Figure 1C. Because the operator controls the retraction of the needle by pressing the button drive 65, needle x can be retracted regardless of whether all the medication has been ejected from the cartridge.

^ This allows the operator to control the amount of medicament injected into the patient, while allowing the front needle 15 to retract toward the patient. housing 20. Referring now to Figures 6-11 in general, and to Figure 6 specifically, an alternative embodiment of an injector cartridge 110 is shown. The alternative embodiment incorporates a retractable needle. automatically at the end of an injection without manually pressing the separate button. The cartridge injector 110 includes two needles, an insertion needle 114 and a rear needle 116 that pierces a plunger 190 that seals the cartridge 170. The insertion needle 114 operates to inject medicament into a patient, and is retained in a releasable manner. by a needle retainer 150. An actuator 130 cooperates with the needle retainer 150, so that; the forward axial displacement of the actuator 130 causes the needle retainer 150 to release the insertion needle 114. A spring 160 then urges the insertion needle 114 rearward, so that the pointed tip of the needle is located within the cartridge injector. The cartridge injector 110 includes a generally cylindrical hollow barrel having a reduced front diameter tip 122. The tip 122 is generally closed having a hole through which the insertion needle 114. projects. The trailing end 124 of the barrel 120 is generally open and is sized to receive the cartridge 170. The needle retainer 150 is positioned within the forward end of the barrel 120, adjacent the tip 122. The needle retainer dramatically holds the insertion needle 114, so that the insertion needle projects forward from the barrel 120, as illustrated in Figure 6. The needle retainer 150 can be attached to the barrel 120 in a variety of ways, including ultrasonic welding, epoxy, or adjustment to Pressure. In the present step, the needle retainer 150 5 is attached to the barrel 120 by means of a snap fit. The insertion needle 114 projects through an axial hole in the needle retainer 150. The needle retainer includes a body portion generally cylindrical 152 at the front end of the needle retainer and a plurality of axially elongated fingers or claws 154 releasably retaining the insertion needle 114. The fingers or claws 154 have radially inwardly projecting projections a restricted portion in the hole of the needle retainer. Preferably, the surface of each projection is configured to conform to the outer surface of the insertion needle 114 to hold the needle in axial alignment with the needle retainer. needle 150. The surfaces of the projections preferably form a continuous surface within the interior of the needle retainer to improve engagement with the insertion needle. The fingers or claws 154 are secured or joined to the external surface d-e insertion needle 114 using an adhesive such as an epoxy. The needle retainer 150 preferably includes four fingers or claws 154, although one or more fingers or claws 154 may be employed depending on factors such as the size of the device 5 and the nature of the deflection member. The exterior of the needle retainer 150 is provided with longitudinally marked grooves or lines between the fingers or claws 154 to facilitate the separation of the fingers or claws when the retraction of the fingers is activated. the needle. Alternatively, the needle retainer 150 may use a holding arrangement rather than being releasably attached to the needle. In the clamping arrangement, a block is fixed to the insertion needle 114.

The ends of the fingers or claws of the needle retainer 154 form inwardly directed fasteners that engage the block to releasably retain the insertion needle. The needle retainer 150 retains the needle of insert 114 against the backward deflection of a spring 160. In the present case, the spring 160 is a helical spring circumscribing the insertion needle 114. As shown in Figure 6, the forward end of the spring 160 rests against the inside the tip of the barrel 122. The rear end of the spring 160 is attached to the insertion needle 114, preferably by a UV curable adhesive. Alternatively, if the clamping arrangement for the needle retainer 150 is used, then the spring can rest against the block fixed to the needle, if desired. The cartridge injector 110 includes an actuator 130 operable to engage the needle retainer; 150 to make the needle retainer ^ * free insertion needle 114, so that the spring 160 push the insertion needle backwards. The actuator 130 is a generally elongated cylindrical member having a hollow axial bore 132. The axial bore 132 has two diameters. The front portion of the axial hole has a larger diameter that is greater than the diameter of the rear portion of the axial hole. The front end of the actuator 130 is generally open to receive the end F posterior of the insertion needle 114 extending towards the axial hole 132 of the actuator. A mounting rod 138 is connected to the rear end of the actuator 130. Preferably, the mounting hub 138 is formed integrally with the actuator 130. In the present case, the mounting rod 138 includes a threaded portion. externally for threadably coupling a plunger 190 in the cartridge 190. A rear needle 160 for piercing the plunger 190 of the cartridge 170 projects rearwardly from the mounting shank 138. The rear needle 116 is firmly connected to the actuator 130, preferably, by a UV curable adhesive. The front portion of the rear needle 114 projects toward the axial hole 132 of the actuator 130. Preferably, the rear needle 114 has an internal hole ^^ that is larger than the outer diameter of the needle. 11 of insertion 114. In this way, insertion needle 114 can be slidably moved within the rear needle 116. As more clearly shown in Figure 10, a seal 146 provides a fluid-tight seal between the insertion needle 114 and the rear needle 116. The back portion of the seal 146 includes a hole dimensioned to receive the front end of the needle F Posterior 116. The front portion of the seal 146 includes a restrained portion dimensioned to receive the smaller diameter insertion needle 114, providing a fluid tight seal around the outer surface of the insertion needle. The forward end 136 of the actuator 130 is configured to cooperate with the rear end of the fingers or claws 154 of the needle retainer 150. In the present case, the front end 136 of the actuator forms a tapered or frusto-conical surface. The trailing end of each finger or claw of the detent needle 154 tapers radially inward, so that the The trailing end of the needle retainer 150 forms a tapered, converging annular surface 156. Configured in this manner, as shown in Figures 8 and 9, when the actuator 130 moves axially forward. - ^ to attach the needle retainer 150, the surfaces co-operating tapers of the actuator and the needle retainer, operate as a wedge to move the fingers or claws of the needle detent 154 radially outward, so that the needle retainer releases the insertion needle 114. The spring 160 then pushes the insertion needle 114 backwards, so that the pointy point of the insertion needle is located within • of the accommodation beyond the reach of the operator. The cartridge injector 110 preferably includes at least one, and preferably two, 20 safety fasteners 140 that prevent the actuator 130 from moving forward until something, and preferably substantially all, of the medicament is expelled from the cartridge 70. Each safety fastener 140 is attached to the actuator 130, and in the present case, the safety fasteners are integrally formed with the actuator. Each safety fastener 140 is an L-shaped arm flexibly. The front end of the safety fastener 140 is attached to the actuator 130 and the safety fastener extends rearwardly. Each safety fastener includes a detent 142 that cooperates with an opening 126 formed in the wall of the barrel 120. In this manner, as shown in Figure 7, when the detent 142 of the safety fastener 140 projects toward the opening. 126, the safety fastener 140 prevents the actuator 130 from moving axially forward. Referring now to Figure 10, preferably, the front end of the detent 142 and the front end of the opening 126 are also tapered to improve the engagement by immobilization of the retainer with the opening. The position of the safety fastener rearwardly of the detent 142 projects radially inward toward the actuator 130, forming a release tab 144. The front end of the edge 172 of the cartridge 170 cooperates with the release tab 144 to release the fastener security 140 as will be discussed later. Referring again to Figure 6, the trailing end of the barrel 120 is generally open, forming a receptacle 124 for receiving the cartridge 170. The cartridge 170 is a generally cylindrical container containing a quantity of medicinal fluid. The rear end of the cartridge 170 is closed, and the front end of the cartridge is open to form an edge 172. The open end of the cartridge 170 can be sealed by a rubber plunger or piston 190. The plunger 190 is generally cylindrical and has one; ' plurality of axially spaced circumferential edges 192, which form a fluid-tight seal between the plunger 190 and the inner surface of the cartridge 170. The front or outer end of the plunger is configured to cooperate with the mounting rod 138 of the cartridge injector. In the present case, the mounting rod 138 is externally threaded and the plunger 190 has corresponding internal threads. The inner end of the plunger 190 adjacent the medicament includes a cavity 196. In this manner, a pierceable wall is formed in the plunger 190 between the cavity 196 and the base of the internal threads. When the cartridge 170 is mounted on the mounting rod 138, the rear needle 116 pierces the wall of the plunger and extends into the cavity 196 formed in the interior of the plunger. The cavity opens into the interior of the cartridge 170, so that when the rear needle 116 projects into the cavity 196, the rear needle is in fluid communication with the interior of the cartridge 170, allowing the medicament to flow from the cartridge to the needle later. After the back needle 116 pierces the wall of the plunger, the wall forms a fluid-tight seal between the plunger 190 and the side of the back needle to prevent the drug from leaking into the barrel 120. The medicament is expelled from the cartridge 190 moving the cartridge axially forward to advance the cartridge. The plunger 190 is mounted on the mounting rod 138, so that the plunger remains stationary while the cartridge 170 advances. The plunger 190 is configured to form a sliding fit with the interior of the cartridge, so that the cartridge 170 can slide over the plunger to eject the medicament from the cartridge. Additionally, the circumferential edges 192 maintain a fluid-tight seal between the plunger and the cartridge, while the cartridge slides over the plunger. When the cartridge 170 advances, the medicament in the cartridge flows out of the cartridge and the rear needle 116. From the posterior needle, the medicament flows into the insertion needle 114 and then into the patient. After the medicament is injected into the patient, the insertion needle 114 can be retracted into the housing 120 as follows. Referring now to Figures 7 and 8, when at least substantially all of the medicament is ejected from the cartridge 170, the trailing edge 172 of the cartridge engages the cartridge. releasing tab 142 of each safety fastener 140. Continuous forward movement of the cartridge 170 folds each - ^ safety fastener 140, displacing the fasteners II 10 radially inwards, thereby removing the detents 142 from the openings 126 in the barrel 120. After the detents 142 are removed from the openings 126, the continuous forward movement of the cartridge 170 displaces the actuator 130 axially forward. The actuator 130 then engages the needle retainer 150 for • release the insertion needle 114 as shown in Figure 9 and described above. In this way, the safety fasteners 140 prevent the forward axial displacement of the actuator 130, preferably until at least substantially all of the medicament is expelled from the cartridge 170. After at least substantially all of the medicament has been expelled from the cartridge 170, the fastener The safety 140 releases the actuator allowing the actuator 130 to engage the needle retainer 150 to release the insertion needle 114. As shown in Figure 9, the spring 160 urges the insertion needle 114 backward, so that the insertion needle is connected with the rear needle 116. In addition, ran is shown in Figure 9, preferably the barrel 120 includes a front portion of reduced diameter that forms an inner annular ridge 125 that engages the front portion of the security fasteners 140. In this manner, the internal flange 125 acts as a stop to prevent additional forward axial displacement of the actuator. The terms and expressions that have been used were used as terms of description and not limitation. There is no intent in the use of such terms and expressions to exclude any equivalents of the features shown and described or portions thereof. It is recognized, however, that various modifications are possible within the scope and spirit of the invention. For example, the second embodiment described above may include a manually operable release for releasing safety fasteners 140, so that the actuator may be actuated to effect retraction before substantially all medicament is expelled from the cartridge. Consequently, the invention incorporates variations that fall within the scope of the following F claims. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

F

Claims (15)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. An injection device for use with a pre-filled medicament cartridge of the type containing a medicament supply and having a pierceable piston positioned at a rear end thereof, the device is characterized in that it comprises: a barrel sized to receive the cartridge and it has a front portion that includes a hole of a reduced diameter; a first needle axially positioned within the portion of reduced diameter and extending outwardly from the front portion of the barrel; a spring placed in the barrel to exert a backward deflection on the needle; A needle retainer placed in the barrel to retain the needle inside the hole against the backward deviation exerted? by the spring; a second needle in fluid communication with the medication in the cartridge; a duct extending between the first needle and the second needle; an actuator that can be operated to release the needle from the needle retainer; wherein the spring urges the duct and the first needle backwards, upon release of the needle from the needle retainer, so that the duct telescopically engages the second needle.

2. A device for injecting medication from a cartridge containing medication, wherein the cartridge includes a front edge, the device is characterized in that it comprises: a housing having an opening for receiving the cartridge; a first needle projecting forward from the housing; a deflection element that deflects the first needle backward; a needle retainer releasably retaining the first needle against deflection of the deflection elements; an axially displaceable actuator that can be operated to engage the needle detent so that the needle retainer releases the first needle after the axial forward movement of the actuator; a fastener that operates to prevent axial forward movement of the actuator; and a release cooperating with the edge of the cartridge to move the fastener.

3. The device according to claim 2, characterized in that the cartridge includes a pierceable piston seal at one end of the cartridge and the device comprises a mounting rod for retaining the piston in a fixed axial position while the medicament is expelled. of the cartridge. The device according to claim 2, characterized in that the device comprises a second needle that telescopically engages the first needle. The device according to claim 4, characterized in that it comprises a seal that provides a fluid-tight seal between the first needle and the second needle. The device according to claim 2, characterized in that the needle retainer comprises a plurality of axially elongated fingers or claws, circumferentially spaced apart. The device according to claim 2, characterized in that the actuator comprises a conduit for receiving the medicament from the cartridge. The device according to claim 2, characterized in that the rear end of the needle retainer includes a tapered drive surface facing rearward and the actuator includes a tapered drive surface facing forward, which is uniformly coupled to the surface actuation of the needle retainer. The device according to claim 2, characterized in that the fastener and the releaser are integrally formed. The device according to claim 2, characterized in that the edge of the cartridge engages the releaser causing the releaser to move the fastener to allow displacement of the actuator when at least substantially all of the medicament is expelled from the cartridge. 11. A medical device for injecting medication from a cartridge containing a cartridge containing medication, wherein the cartridge includes a front edge, the device is characterized in that it comprises: a housing for receiving the cartridge; a first needle projecting forward from the housing; retraction means for retracting the first needle into the housing; retaining means for releasably retaining the first needle against retraction toward the housing; releasing means for releasing the first needle from the retaining means; safe means to prevent the release means from releasing the first needle; and means for preventing the security means from allowing the release means to release the needle from the retaining means. The device according to claim 11, characterized in that the cartridge can be moved within the housing and the security means operate in response to the displacement of the cartridge. The device according to claim 11, characterized in that the cartridge can be moved within the housing and the release means operate in response to the displacement of the cartridge. The device according to claim 11, characterized in that the cartridge includes a pierceable plunger that seals an end of the cartridge of the device comprising a mounting rod to maintain the plunger in a fixed axial position while the medicament is expelled from the cartridge. 15. The device according to claim 5, characterized in that the device comprises a second needle that telescopically engages the first needle. 16; The device according to claim 15, characterized in that it comprises a 10 seal that provides a fluid tight seal between the first needle and the second needle. The device according to claim 11, characterized in that the retaining means comprise a plurality of fingers or claws 15 axially elongated, circumferentially spaced. 18. The device according to claim 11, characterized in that the release means comprises a conduit for receiving the medicament from the cartridge. 19. The device according to claim 11, characterized in that the rear end of the retaining means includes a tapered drive surface oriented rearwardly and the release means include a surface of 25 forward tapered drive, which is coupled uniformly to the drive surface of the retaining means. F 20. The device according to claim 11, characterized in that the security means and the neutralization means are integrally formed. - '21. The device according to claim 11, characterized in that the edge of the cartridge engages the neutralization means causing F 10 the neutralization means displace the security means to allow the displacement of the release means, when at least substantially all the medication is expelled from the cartridge.