Pen needle

Abstract: A pen needle being of a type that is forced fit into an adaptor on the pen using threads on the pen needle and corresponding threads in a cavity of a pen needle magazine dispenser designed to be received and carried in a cap of a medication delivery pen. The dispenser having a cover rotatably mounted on a circular shaped container to cover a plurality of cavities, wherein each cavity is dimensioned to receive one of the pen needles. The cover includes a slot that is rotated into alignment with one of the cavities in the container to provide the user with access to one unused pen needle and thereby permit the pen needle to be mounted on the pen. After use the used pen needle is returned to the cavity and the cover is rotated until the slot is aligned with another cavity containing the next unused pen needle to be used during the next injection.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The subject invention relates to a pen needle assembly for use with a medication delivery pen. 2. Description of Related Art Hypodermic syringes are used to deliver selected doses of medication to patients. The prior art hypodermic syringe includes a syringe barrel having opposed proximal and distal ends. A cylindrical chamber wall extends between the ends and defines a fluid receiving chamber. The proximal end of the prior art syringe barrel is substantially open and receives a plunger in sliding fluid tight engagement. The distal end of the prior art syringe barrel includes a passage communicating with the chamber. A needle cannula is mounted to the distal end of the prior art syringe barrel, such that the lumen of the needle cannula communicates with the passage and the chamber of the syringe barrel. Movement of the plunger in a proximal direction draws fluid through the lumen of the needle cannula and into the chamber. Movement of the plunger in a proximal-to-distal direction urges fluid from the chamber and through the lumen of the needle cannula. Medication to be injected with the prior art hypodermic syringe often is stored in a vial having a pierceable elastomeric seal. Medication in the prior art vial is accessed by piercing the elastomeric seal with the needle cannula. A selected dose of the medication is drawn into the chamber of the syringe barrel by moving the plunger a selected distance in a proximal direction. The needle cannula is withdrawn from the vial, and the medication is injected into a patient by moving the plunger in a distal direction. Some medication, such as insulin is self-administered. The typical diabetes patient will require injections of insulin several times during the course of the day. The required dose of insulin will vary from patient to patient, and for each patient may vary during the course of the day and from day to day. Each diabetes patient will establish a regimen that is appropriate for his or her own medical condition and for his or her lifestyle. The regimen typically includes some combination of a slow or medium acting insulin and a faster acting insulin. Each of these regimens may require the diabetes patient to periodically self-administer insulin in public locations, such as places of employment or restaurants. The required manipulation of the standard prior art hypodermic syringe and vial can be inconvenient and embarrassing in these public environments. Medication delivery pens have been developed to facilitate the self-administration of medication. A prior art medication delivery pen is identified generally by the numeral 1 in Fig. 1. Pen 1 contains a cartridge with sufficient medication for several doses. The prior art cartridge has opposed proximal and distal ends. The distal end is closed by a pierceable and resealable rubber septum identified by the numeral 2 in Fig. 1. The proximal end receives a stopper in sliding fluid-tight engagement. The prior art cartridge is disposed in an elongate pen-like body 4 with a proximal end (not shown) and an opposed distal end 6. The proximal end of the pen body includes a plunger for selectively driving the stopper of the cartridge in the distal direction and a dose setting mechanism for determining the distance through which the plunger and stopper can move. Distal end 6 of pen body 4 includes an array of threads 8 for threaded engagement with a pen needle assembly 90. Pen needle assembly 90 includes a needle cannula 91 with opposed proximal and distal points 92 and 93 and a threaded mounting skirt 94 which surrounds the proximal tip 92. Mounting skirt 94 is threadably engageable with threads 8 on distal end 6 of pen body 4. A safety shield 95 is releasably engaged over distal point 93 and portions of mounting skirt 94 to prevent accidental needle sticks. A person who must periodically inject doses of medication will carry a medication delivery pen 1 and a supply of pen needle assemblies 90. Each pen needle assembly 90 has its needle cannula 91 safely and sterility sealed in its own shield 95, and is accessed immediately prior to administering a dose of medication. Pen needle assembly 90 then is mounted to distal end 6 of prior art pen 1. This mounting causes proximal point 92 of needle cannula 91 to pierce rubber septum 2 of the cartridge, to place needle cannula 91 in communication with the medication in pen 1. Pen 1 then is used to inject the selected dose of medication. After completing the injection, needle assembly 90 is separated from pen 1 and is discarded. Pen 1 may be used repeatedly in this manner until the medication is exhausted. Such prior art pens offer many conveniences and efficiencies. However, the storage of unused needles and the final disposal of used needles has presented problems. In particular, supplies of new needles often are loosely scattered in the bottom of purses or briefcases, and used needles are often disposed of unsafely. FR-A 2,623,403 provides a method of fitting and removing syringe needles without manual contact therewith, characterised in that the needle, provided with a collar, is mounted entirely within a socket, of which a portion is shaped internally in a manner complementary to the lower portion of said collar in order to prevent rotation of the latter when is it positioned in the said socket, and in that the needle thus fitted is then taken up for use or removed after use by means of an end piece fixed to the syringe and shaped in a manner complementary to the upper portion of the said collar for automatic coupling to the latter mounted in its socket, for example by a rotation movement, and for automatic disconnection from the said collar replaced in the said socket after use of the needle, for example by a rotation movement. The invention of FR-A-2,623,402 also relates to the device for implementation of this method. SUMMARY OF THE INVENTION According to the present invention, there is provided a needle assembly for use with a medication delivery pen, said needle assembly comprising: a hub; means on said hub for force-fit attaching said hub to a medication delivery pen which includes an adaptor that receives said force-fit needle assembly, said adaptor (50) having a set of threads (52) intended to mate with a conventional set of threads (8) on the medication delivery pen or said adaptor being integrally molded onto or permanently attached to the medication delivery pen; and a cannula mounted within said hub and having a distal point and a proximal point; characterised in that said force-fit attaching means of said hub includes a proximal end of triangular cross-section intended to be received in a matching triangular shaped hole of the adaptor; and said hub includes a set of threads intended to be used to drive said needle assembly into said triangular shaped hole of the adaptor when said needle assembly is located in a threaded cavity and said needle assembly is unthreaded from the threaded cavity using the adaptor and with the triangular shaped proximal end being inserted into the triangular shaped hole. DETAILS OF THE INVENTION The subject invention relates to a needle assembly according to claim 1. A pen needle dispenser for use with a needle assembly of the present invention includes a magazine dispenser having a cover rotatably mounted on a container with a plurality of cavities, with each cavity dimensioned to receive a pen needle assembly of the present invention. The cover includes a slot that is rotated into alignment with a cavity in the container that contains an unused pen needle. When the slot is aligned with such a cavity, the user inserts an adaptor on the medication delivery pen into the cavity and rotates the pen to mount the unused pen needle on the medication delivery pen. After the injection has been performed, the used pen needle is returned to the cavity by inserting the used pen needle in the cavity and rotating the pen to detach the pen needle from the adaptor on the pen. The user then rotates the cover until the slot in the cover provides access to the next cavity containing another unused pen needle to be used during the next injection. An object of the present invention is to provide a needle assembly which can be used in a way to prevent the pen needle from being reused by having it covered in the pen needle magazine dispenser. In addition, once the cover has been rotated to the next cavity, the pen needle magazine dispenser provides means to prevent the cover from rotating back to used pen needles. Another object of the present invention is a needle assembly which can be used in a way to provide a user with a convenient way to carry, dispose of and keep track of their personal pen needle usage. A pen needle magazine dispenser may be designed to fit in the cap of the medication delivery pen and contain a predetermined number of pen needles in respective cavities, with each cavity being sealed by a numbered label or sterility membrane. The numbered labels may indicate how many unused pen needles remain in the pen needle magazine dispenser. Furthermore, there is disclosed an adaptor that may be threaded onto the distal end of conventional medication delivery pens so that the pen needle of the present invention can be used with such conventional medication delivery pens. The pen needle includes a base having threads on one end drive the other end of the base into the adaptor to create a friction fit between the adaptor and the base. The driving force is generated by using the adaptor to rotate the pen needle relative to its cavity and thereby unthread the pen needle from the cavity and force fit it in to the adaptor. These and other aspects, features and advantages of the present invention will become apparent the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view of a prior art pen needle and the distal end of a prior art medication delivery pen with which the present invention is intended to be used; Fig. 2 is an exploded perspective view of a cap on a medication delivery pen and a pen needle magazine dispenser which employ a needle assembly according to the present invention; Fig. 3 is a perspective view of the pen needle of Fig. 2 being attached to an adaptor threaded on the distal end of a medication delivery pen; Fig. 4 is an exploded perspective view of the pen needle magazine dispenser shown in Fig. 2; Fig. 5 is an exploded perspective view of the adaptor and pen needle with a partial cross-sectional view of the pen needle magazine dispenser; and Fig. 6 is another exploded view of the adaptor and pen needle. DETAILED DESCRIPTION A pen needle magazine dispenser with a needle assembly 100 in accordance with the subject invention is identified generally by the numeral 10 in Figs. 2, 3 and 4. Fig. 2 is an exploded perspective view of a cap 3 on a medication delivery pen 1 and a pen needle magazine dispenser 10. Cap 3 includes a clip 5 and an open end 7 dimensioned to receive pen needle magazine dispenser 10. Fig. 3 is a perspective view showing the operation of inserting an adaptor 50 on distal end 6 of medication delivery pen 1 into pen needle magazine dispenser 10 and the rotational motion used to attach a pen needle assembly 100 to adaptor 50. As shown in the exploded perspective view in Fig. 4, pen needle magazine dispenser 10 includes a cover 20 and a container 30. Container 30 includes a plurality of cavities 31 about the circumference of container 30, with each cavity 31 dimensioned to receive a pen needle assembly 100, described further below. Each pen needle assembly 100 is originally sealed in its respective cavity 31 by a disc shaped label or sterility barrier 150 that is attached to an upper surface 32 of container 30. Label 150 provides sterility for unused pen needle assemblies 100 contained in each cavity 31 and a simple means for the user to identify whether the pen needle assembly in a particular cavity has been used. Pen needle magazine dispenser 10 is initially loaded with a predetermined number of pen needle assemblies 100 in the plurality of cavities 31, with all of the cavities 31 being sealed by sterility barrier 150 and having a number 151 thereon corresponding to each cavity 31. Each number 151 or other indicia on label 150 indicates to the user how many unused pen needle assemblies 100 remain in pen needle magazine dispenser 10. Label 150 includes a central opening 152 through which cover 20 is mounted on container 30 and is scored at the location of each cavity 31 without, of course, affecting the integrity of the seal to allow for controlled breaking when adaptor 50 on medication delivery pen 1 is pressed through label 150 when loading pen needle assembly 100 on adaptor 50. The controlled breaking of the scored area allows adaptor 50 on medication delivery pen 1 to be inserted through label 150 to mate with pen needle assembly 100 within cavity 31. After pen needle magazine dispenser 1, shown in Fig. 4, is loaded with new needle assemblies 100 and fully assembled with cover 20 rotatably mounted on container 30 and label 150 attached to upper surface 32 over one of cavities 31, cover 20 is rotated with respect to container 30 to move slot 21 over the first loaded cavity 31. As shown in Fig. 4, container 30 includes a central opening 37 and a plurality of ratchet teeth 33 selectively spaced around an outer wall 35 of container 30. Container 30 also includes a flange 34 that extends outwardly from outer wall 35 of container 30 below ratchet teeth 33 and an end of travel lock pin 36 that extends up from flange 34. End of travel lock pin 36 works with a similar end of travel lock key 26 located on the underside of cover 20 to stop rotation of cover 20 on container 30 when all cavities have passed under slot 21. Cover 20 includes a central post 22 having an enlarged head 23. In addition, cover 20 includes an outer lip 27 around its circumference that extends down and over container 30, when cover 20 is attached to container 30. Outer lip 27 includes a ratchet tooth 25 extending therefrom in the direction of container 30 that is dimensioned to work with the plurality of ratchet teeth 33 on container 30 to prevent cover 20 from rotating in a predetermined direction. Cover 20 is rotatably attached to container 30 after container 30 has been loaded with pen needle assemblies 100 and label 150 has been attached to upper surface 32 of container 30 by inserting central post 22 into central opening 37 in container 30 until enlarged head 23 snaps to central opening 37. When enlarged head 23 snaps into central opening 37, cover 20 is attached to container 30 such that ratchet teeth 33 on container 30 engage with ratchet tooth 25 extending from cover 20 to only permit cover 20 to rotate in one direction, i.e., a clockwise direction. Therefore, cover 20 is not permitted to rotate in the counter-clockwise direction or to move slot 21 back over cavities 31 containing used pen needles 100. Of course, when cover 20 is attached to container 30 it is important to locate end of travel lock key 26 on cover 20 adjacent to end of travel lock pin 36 on container 30, such that cover 20 can proceed with a full clockwise rotation on container 30. Therefore, when all cavities have been accessed using slot 21 on cover 20 and cover 20 has completed a complete clockwise rotation on container 30, end of travel lock key 26 on cover 20 will again be adjacent to end of travel lock pin 36 on container 30 but now will prevent further rotation in the clockwise direction. In the current embodiment, cover 20 can never be rotated in the counterclockwise direction on container 30 because of the above-described interaction of ratchet teeth 25 and 33. As described above, container 30 includes a plurality of cavities 31 around its circumference that are dimensioned to receive pen needle assemblies 100, more clearly shown in Figs. 5 and 6 and further described below. Fig. 5 shows a cross-sectional view of one of said plurality of cavities 31 and Fig. 6 more clearly shows adaptor 50. As shown in Fig. 5, each cavity 31 includes an open end 39 leading to an upper section 42 and a bottom section 41 leading to a closed end 44. Upper section 42 includes a retaining ring 46 that mates with a matching retaining ring 55 on adaptor 50, when adaptor 50 is inserted into cavity 31 to attach or detach pen needle assembly 100 to adaptor 50. Bottom section 41 has a smaller diameter than upper section 42 with a shelf 43 formed where sections 41 and 42 meet. A set of threads 45 are located in the bottom part of upper section 42 adjacent to shelf 43 and bottom section 41 is dimensioned to receive a distal point 104 on pen needle assembly 100. As shown in Figs. 5 and 6, pen needle assembly 100 includes a hub 102 having a triangular shaped proximal end 109 and a distal end 107 having a set of threads 101 thereon dimensioned to mate with the set of threads 45 within cavities 31. A needle cannula 103 is mounted within hub 102 and includes a distal point 104 and a proximal point 105, wherein proximal point 105 extends from triangular shaped proximal end 109 and distal point 104 extends out of distal end 107 on hub 102. Proximal end 109 also includes one or more splines 110 to improve the rotational operation of hub 102 within cavity 31 and increase the force-fit between hub 102 and adaptor 50. After a plurality of pen needle assemblies 100 have been loaded into pen needle magazine dispenser 10 and assembled, as shown in Fig. 4, pen needle magazine dispenser 10 is ready for mounting in opening 7 of cap 3, as shown in Fig. 2. As shown in Fig. 3, each newly designed pen needle assembly 100 within cavity 31 can only be removed and mounted on a medication delivery pen having an adaptor 50. As shown in Fig. 5, adaptor 50 includes an open proximal end 51 having a set of threads 52 dimensioned to mate with threads 8 on distal end 6 of conventional medication delivery pen 1. Adaptor 50 also includes a unique triangular shaped opening 53 in its distal end 54. After adaptor 50 has been threaded onto distal end 6 of pen 1, distal end 54 of adaptor 50 is used to remove pen needle assembly 100 from cavity 31 by inserting triangular shaped proximal end 109 of needle assembly 100 into triangular shaped opening 53 in adaptor 50. When triangular shaped proximal end 109 of needle assembly 100 is inserted into triangular shaped opening 53 in adaptor 50, rotation of medication delivery pen 1 causes pen needle assembly 100 to rotate within cavity 31 and drive triangular shaped proximal end 109 of needle assembly 100 into a forced fit with triangular shaped opening 53 in adaptor 50. As pen 1 is rotated and needle assembly 100 is driven into adaptor 50, proximal point 105 of pen needle assembly 100 pierces rubber septum 2 of the cartridge in pen 1 to place needle cannula 103 in communication with medication contained within the cartridge in pen 1. The forced fit also holds proximal point 105 within rubber septum 2 and needle assembly 100 within adaptor 50 during the injection of medication from the cartridge in pen 1. After use, the used pen needle assembly 100 mounted on adaptor 50 on medication delivery pen 1 is reinserted into cavity 31 until retaining rings 46 and 55 mate and the set of threads 101 on pen needle assembly 100 come into contact with the set of threads 45 within cavity 31. Medication delivery pen 1 is then rotated in the opposite direction to thread pen needle assembly 100 back into cavity 31 and pen 1 is then pulled out of container 30 as pen needle assembly 100 is pulled out adaptor 50. The user then rotates cover 20 until slot 21 is aligned with the next cavity 31 having an unused pen needle 100 that is still covered by label 150. As cover 20 is rotated ratchet tooth 25 travels over one set of ratchet teeth 33 on container 30, which then prevents cover 20 from rotating in the opposite direction. Of course, an alternative to the uni-directional cover shown in the drawings and described above would be a design that allows the user to rotate slot 21 back to previously used needles. In that case, no ratchet mechanism would be needed but the other features could still be used in such a device. However, as described above and shown in the drawings, the current design allows the user to repeatedly rotate cover 20 to each cavity 31 until all of the pen needle assemblies 100 have been used and the last cavity 31 has been encountered by slot 21 on cover 20. That last cavity could be left empty so that the user will know that all pen needle assemblies 100 have been used and thereby indicate that pen needle magazine dispenser 10 should now be properly disposed of. In addition, by providing an empty cavity 31 with all filled cavities 31 being fully enclosed behind cover 20, all the used pen needle assemblies 100 and their proximal points 105 would be protected from accidental needle sticks, since cover 20 would no longer be able to rotate in either direction. As explained above, further rotation would be prevented by interaction between end of travel lock pin 36 on container 30 and end of travel lock key 26 on cover 20. If it is desired to use all the cavities 31 in container 30 to hold pen needle assemblies 100, the apparatus of the present invention can have a final rotational movement that is limted to a one-half (1/2) unit turn. In that case, slot 21 would be finally positioned between the first cavity and the last cavity with all pen needle assemblies 100 being covered and contained within container 30 and cover 20 being prevented from rotation in either direction. While the invention has been described with respect to a preferred embodiment, it is apparent that various changes can be made. For example, adaptor 50 can be integrally molded onto or permanently attached to distal end 6 of a medication delivery pen 1 rather than being a separate part.

Claims: A needle assembly (100) for use with a medication delivery pen (1), said needle assembly comprising: a hub (102); means on said hub for force-fit attaching said hub to a medication delivery pen (1) which includes an adaptor (50) that receives said force-fit needle assembly, said adaptor (50) having a set of threads (52) intended to mate with a conventional set of threads (8) on the medication delivery pen (1) or said adaptor (50) being integrally molded onto or permanently attached to the medication delivery pen (1); and a cannula (103) mounted within said hub (102) and having a distal point (104) and a proximal point (105); characterised in that said force-fit attaching means of said hub (102) includes a proximal end (109) of triangular cross-section intended to be received in a matching triangular shaped hole (53) of the adaptor (50); and said hub (102) includes a set of threads (101) intended to be used to drive said needle assembly into said triangular shaped hole (53) of said adaptor (50) when said needle assembly is located in a threaded cavity (31) and said needle assembly is unthreaded from the threaded cavity (31) using the adaptor and with the triangular shaped proximal end (109) being inserted into the triangular shaped hole (53). A needle assembly according to Claim 1, wherein said proximal point (105) of said cannula (103) extends out of said triangular proximal end (109) such that when said triangular shaped proximal end (109) of said needle assembly is fully received within said matching triangular shaped hole (53) in the medication delivery pen (1), said proximal point (109) extends into the medication delivery pen (1) a sufficient distance to pierce a septum within the medication delivery pen (1).

Inventors: ALLEN WILLIAM J, DIBIASI MICHAEL A, MURRAY MATTHEW, NGUYEN TUAN V, REED SCOTT, STEIN JEFFREY A, WEST ROBERT E, ALLEN, WILLIAM J., DIBIASI, MICHAEL A., MURRAY, MATTHEW, NGUYEN, TUAN V., REED, SCOTT, STEIN, JEFFREY A., WEST, ROBERT E.
Applicants: BECTON DICKINSON CO, BECTON, DICKINSON AND COMPANY
Application year: 1998
Main classification: A61M5
IPC codes: A61M5, B65D83