WO2012058192A1

WO2012058192A1 - Automatic medication injection device

Info

Publication number: WO2012058192A1
Application number: PCT/US2011/057618
Authority: WO
Inventors: Michael L. Langan
Original assignee: 7944942 Canada Inc.
Priority date: 2010-10-26
Filing date: 2011-10-25
Publication date: 2012-05-03

Abstract

A device for injecting a medication, a medication cartridge and a method for injecting a medication in a subject are disclosed. The present device comprising a first housing, a second housing and injection mechanism rotating the housing about their axis from a first orientation in which the injection mechanism cannot be actuated to a second orientation in which the injection mechanism can be actuated, while the two housings remain attached.

Description

AUTOMATIC MEDICATION INJECTION DEVICE

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to an automatic device for injecting medication in a subject. Description of the Related Art

Anaphylaxis is a severe medical emergency that if not treated quickly and appropriately can be fatal. It occurs unexpectedly and may progress rapidly in patients of all ages, but most often in the young and otherwise healthy. The most common cause of anaphylaxis is food allergy, especially to peanuts, which is increasing in prevalence. Rapid diagnosis is essential and immediate injection of. intramuscular epinephrine is the treatment of choice, the response to which is often dramatic and potentially life saving. The early injection of epinephrine is the most important factor in anaphylaxis outcome. People who survive near fatal anaphylactic reactions receive intramuscular injections promptly while those who die do not. Death from anaphylaxis occurs most often in teenagers and young adults and is directly related to receiving injected epinephrine too late, inaccurately (outside the muscle), or not at all. Anaphylaxis most often occurs unexpectedly and in the absence of a trained health care professional. Because exposure is unpredictable the reaction may occur quickly and the patient may not be near medical help at the time of exposure, patients who are subject to severe anaphylaxis must carry epinephrine at all times. It is also necessary that the patient be able to self-administer the epinephrine during an anaphylactic attack.

An automatic injection device sold under the name EpiPen was introduced in 1980, and currently dominates the market for automatic epinephrine injection devices. Although there are other brands of auto-injector, past and present, the design is essentially the same. These autoinjectors are designed as a tubular device with a spring activated concealed needle that, when triggered, springs forward to deliver a dose of epinephrine. The EpiPen^® and EpiPen^® Jr. devices contain 0.3 and 0.15 milligrams of epinephrine respectively and are designed for single dose intramuscular injection for emergency treatment of anaphylaxis. Various examples of automatic injection devices can also be found in U.S. Patent

Nos. 3,964,481 , 4,031 ,893, 4,394,893, 4,661 ,098, 5,267,963, 6,099,503, 6,203,530, 6,767,336, 6,979,316, 7,390,319, 7,416,540, 7,621 ,891 , 7,648,483, and U.S. Patent Application Publication Nos. 2002/0095120, 2004/0039337, 2004/0211806, 2005/0171477, 2005/0273054, 2007/0100288, 2008/0097312, 2008/0132838, and 2008/0269347. Recent studies indicate a number of problems with automatic injection devices such as the EpiPen^®. The EpiPen^® device is difficult to use, can only be used once, has only two fixed doses of epinephrine and is considered burdensome. Many patients are noncompliant with the EpiPen^® device and do not carry it with them at all times for various reasons including problems with size, shape and appearance. The EpiPen^® device has a counter-intuitive design that can promote accidental misfiring into a digit. The needle length of the EpiPen^® device is not sufficient for intramuscular injection in up to one-third of children and adults, and in these individuals the epinephrine is delivered subcutaneously rather than intramuscularly. Subcutaneous epinephrine absorption is delayed and can result in an adverse outcome as dose, timing, and absorption of epinephrine are of paramount importance in anaphylaxis outcome.

Therefore, it can be appreciated that anaphylaxis remains an important and avoidable cause of death and that currently available automatic injection devices have a number of problems in form, function, and appeal. These problems can contribute to incorrect use, misuse, not carrying the unit as prescribed (non-compliance), and can result in an adverse outcome including death. Disadvantages in present medication delivery devices may promote user error which can result in adverse outcomes.

What is needed therefore is a portable and easy to use auto-injector for rapid intramuscular injection of epinephrine.

SUMMARY OF THE INVENTION The present invention provides an automatic epinephrine injection device that can also be a fashion accessory. The automatic epinephrine injection device is designed for portability, ease of use, and safety. In one form, the automatic epinephrine injection device is a bracelet that includes two semi-circular plastic hollow arms connected by a rotating hinge. The bracelet arms are of unequal length, with the shorter arm housing an epinephrine needle injection mechanism and the longer arm including the trigger mechanism. The epinephrine is contained in a removable unit that is inserted into the tubular arm of the bracelet and locked into the bracelet with a cap. This removable unit contains a measured dose of epinephrine and the needle injector unit. In order to use the automatic epinephrine injection device for injection one of the arms is rotated 180 degrees and then locked into place. The smaller of the two arms is designed to conform to the curves of the vastus lateralis muscle of the thigh enabling the patient, or first responder, to easily target the injection area. In one version, the device is battery operated and to prevent accidental misfiring, the circuit from the trigger mechanism to activate the injection is only complete when the arm is locked in place at 180 degrees. The degree of curvature on the arcuate portion of the opened bracelet that houses the epinephrine needle injection mechanism can have a degree of curvature of less than 180 degrees to allow the receipt of a contoured injectable site. Alternatively, the epinephrine can be contained in a non-removable unit. This version of the automatic epinephrine injection device can have a non-removable unit for the epinephrine, but still have all the twisting to activate features. The unit remains part of the device, and the epinephrine can be reloaded into the unit.

An automatic epinephrine injection device according to the invention is designed with the user in mind and is simple to use with only three main steps involved: Twist, Turn, and Press. This automatic epinephrine injection device can reduce accidental injection because the steps are intuitive and in order to activate the trigger mechanism of one version of the automatic epinephrine injection device, the arms must be fully extended at 180 degrees. The automatic epinephrine injection device can include a replaceable medication cartridge that can be manufactured with more appropriate weight and age adjusted doses as opposed to the fixed doses in currently available automatic epinephrine injection devices.

The automatic epinephrine injection device according to the invention improves auto-injector form and function, but can also be fashionable. The automatic epinephrine injection device can be worn as a bracelet, or attached to a backpack or purse strap, or hung from a hook without the need for an external device or sheath (i.e., the EpiPen^® holsters). The automatic epinephrine injection device can be designed as an attractive accessory that also happens to be a life saving medical device. Although no formal studies have been done examining why teenagers and young adults do not carry currently available automatic injection devices, anecdotal evidence suggests that they view currently available automatic injection devices negatively, that is these devices do not conform to a teenage or young adult lifestyle in that it is difficult to carry in many situations. Some of the anecdotal reports on perceptions of currently available automatic injection devices included such descriptions as stigmatizing, embarrassing, uncool, unhip, unfashionable and geeky. Sadly, some of these anecdotal reports were obituaries on young people and these negative perceptions were being reported by family members to explain why their loved one was not carrying an automatic injection device on them when they developed anaphylaxis. An automatic epinephrine injection device according to the invention solves these problems in that it is designed to be portable, intuitive and easy to use, and fashionable.

An automatic epinephrine injection device according to the invention meets fashionability, appeal, conformity and accessibility standards. The automatic epinephrine injection device can be designed in the form of a round or oval bangle bracelet. It can be worn as a bracelet, or attached to a backpack, stroller, bicycle rack, book bag or rear view mirror. It is a medical device also designed as a fashion accessory that you can take with you wherever you go. The device is designed for accessibility by being capable of being hung or worn by an individual. An automatic epinephrine injection device according to the invention is easy to operate. To use the device, the bracelet is twisted 180 degrees forming a generally S shape where the two parts of the bracelet (e.g., semicircular arcs) will lock in place and activate the trigger mechanism. The only time one would choose to rotate the bracelet to this degree would be when one intends to use it for injection of a medication. The trigger mechanism is not activated until it is locked in place. A cap of a medication cartridge at one end of the bracelet can be rotated 120 degrees to open the injection site of the bracelet. The semicircular arc can be pressed against the thigh or shoulder and the trigger is pressed. The device can be used for emergency situations, and the medication can consist essentially of epinephrine. The general instructions for automatic epinephrine injection device according to the invention can be just 3 words: "Twist, Turn, Press," or "TTP". Moreover, it is intuitively designed so that the learning process is immediate. The instructions can be given in pictures. If a second dose of epinephrine is required, the cap is twisted another 120 degrees to allow a second epinephrine injection. An automatic epinephrine injection device according to the invention provides accuracy. The design of the semicircular arc makes it simple to find the target area for injection. It is roughly shaped like the contours of the deltoid and vastus lateralis making it an intuitive process. In one example form, the needle length can be 2 centimeters for a 0.15 milligram dose and 3 centimeters for a 0.3 milligram dose to ensure intramuscular rather than subcutaneous injection.

An automatic epinephrine injection device according to the invention provides safety. Digital autoinjection would be very unlikely with this device. By rotating the cap 120 degrees, the exposed needle retracts back into the bracelet after the injection.

The replaceable medication cartridges enable a user to reload the automatic epinephrine injection device simply if need be. The medication cartridges are much easier to carry than carrying multiple currently available automatic injection devices. The amount of the injection is very small so they can be designed for multiple doses. The replaceable medication cartridges of the invention can be designed to be replaced after a period of time (e.g., every three months). The shelf life of currently available automatic injection devices is generally one year and it is recommended that currently available automatic injection devices be stored at 25°C 5 with "excursions permitted" to 15-30°C. These parameters increase the shelf life of currently available automatic injection devices but also increase the chances that the currently available automatic injection devices will stay on the shelf. The replaceable medication cartridges of the invention may have a shorter shelf life but are made for an active lifestyle such that a user can bring replaceable medication cartridges anywhere. Replacing the medication cartridge regularly (e.g., every three months) in a device promotes diligence and vigilance and a sense of control. Alternatively, the medication cartridge remains fixed to the device, and the epinephrine can be reloaded into the medication cartridge using a syringe.

With currently available automatic injection devices, a user is stabbing a scary looking sharp needle into someone. With an automatic epinephrine injection device according to the invention, a user is putting a curved object against the leg and pressing an actuator button. This improves comfort level dramatically. Furthermore, the present device has the advantage to eliminating misfiring of the medication when in the locked first orientation.

In one aspect, the invention provides a device for automatically injecting a medication in a subject. The automatic injection device includes a first housing, a second housing rotatably attached to the first housing, and a medication cartridge attached at least partially within the first housing. The medication cartridge includes a chamber for containing the medication and includes a hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle. The proximal end of the needle is in fluid communication with the chamber. The device includes an injection mechanism for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle. The injection mechanism also moves the needle from a first position in which the distal end of the needle is within a wall of the first housing to a second position in which the distal end of the needle extends outward beyond an outer surface of the wall of the first housing for injection of the medication in the subject. The first housing and the second housing can be rotated from a first orientation in which the injection mechanism cannot be actuated to a second orientation in which the injection mechanism can be actuated. In accordance with one aspect of the present invention, there is provided a device for injecting a medication in a subject, the device comprising: a first housing; a second housing attached to the first housing; a medication cartridge including a chamber for containing the medication and including a hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle, the proximal end of the needle being in fluid communication with the chamber, the medication cartridge being dimensioned for attachment at least partially within the first housing or the second housing; an injection mechanism for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from a first position in which the distal end of the needle is within a wall of the first housing and a second position in which the distal end of the needle extends outward beyond an outer surface of the wall of the first housing or the second housing; and an actuator which can be placed in electrical and/or mechanical communication with the injection mechanism, wherein the first housing and the second housing can be moved from a first orientation of the first housing and the second housing in which the actuator cannot be placed in electrical or mechanical communication with the injection mechanism to a second orientation of the first housing and the second housing in which the actuator can be placed in electrical or mechanical communication with the injection mechanism, and wherein when the first housing and the second housing are in the second orientation, the actuator can be actuated for initiating movement of the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for initiating movement of the needle from the first position to the second position.

In accordance with another aspect of the device described herein, the first and second housing are moved by rotation around their axis from the first orientation to the second orientation. In accordance with another aspect of the device herein described, the first housing and the second housing are in the first orientation, the first housing and the second housing form a closed curve.

In accordance with yet another aspect of the device herein described, the first housing and the second housing are in the first orientation, the first housing and the second housing form a polygon.

In accordance with still another aspect of the device herein described, the first housing and the second housing are in the first orientation, the first housing and the second housing form a perimeter having a length, and the first housing forms less than half of the length of the perimeter.

In accordance with yet still another aspect of the device herein described, the first housing and the second housing are in the first orientation, the first housing and the second housing form a toroid.

In accordance with a further aspect of the device herein described, the surface of the toroid is a torus.

In accordance with a further aspect of the device described herein, the medication cartridge is dimensioned for attachment at least partially in the first housing.

In accordance with yet a further aspect of the device herein described, the wall of the first housing is a side wall of the first housing such that the needle extends laterally from an axis of the first housing outward beyond an outer surface of the side wall of the first housing.

In accordance with still a further aspect of the device described herein, the injection mechanism comprises: a plunger slidingly arranged in the chamber for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from the first position to the second position; a spring engaging the plunger and a portion of the cartridge, the spring biasing the plunger toward the needle, the spring having a first working length in which the plunger is in a ready position before moving the medication from the chamber and before moving the needle from the first position to the second position, and the spring having a second working length in which the plunger is in an activated position in which the plunger has moved the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and the plunger has moved the needle from the first position to the second position; and a releasable catch for maintaining the plunger in the ready position until the actuator is actuated, wherein actuating the actuator releases the catch and thereby allows the spring to move the plunger to the activated position. In accordance with yet still a further aspect of the device herein described, when the first housing and the second housing are in the second orientation and the actuator is actuated, the actuator is mechanically linked to the catch for releasing the catch.

In accordance with another aspect of the device described herein, the actuator is proximal the medication cartridge, and injection device In accordance with one embodiment of the device herein described, when the first housing and the second housing are in the second orientation and the actuator is actuated, the actuator is electromechanically linked to the catch for releasing the catch.

In accordance with another embodiment of the device herein described, the injection mechanism comprises: a plunger slidingly arranged in the chamber for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from the first position to the second position; a spring engaging the plunger and a portion of the cartridge, the spring biasing the plunger away the needle, the spring having a first working length in which the plunger is in a ready position before moving the medication from the chamber and before moving the needle from the first position to the second position, and the spring having a second working length in which the plunger is in an activated position in which the plunger has moved the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and the plunger has moved the needle from the first position to the second position; a source of compressed fluid; and a fluid conduit in fluid communication with the source of compressed fluid and a section of the chamber on a side of the plunger opposite the needle, wherein actuating the actuator releases compressed fluid into the section of the chamber thereby moving the plunger to the activated position.

In accordance with yet another embodiment of the device herein described, the fluid conduit includes a valve between the source of compressed fluid and the section of the chamber, and when the first housing and the second housing are in the second orientation and the actuator is actuated, the actuator is electrically or mechanically linked to the valve such that the valve releases compressed fluid into the section of the chamber.

In accordance with still another embodiment of the device herein described, the first housing includes an opening in the wall of the first housing, and the needle passes through the opening when the needle moves from the first position to the second position.

In accordance with yet still another embodiment of the device herein described, the opening is covered with a seal, and the needle punctures through the seal when the needle moves from the first position to the second position.

In accordance with a further embodiment of the device herein described, the medication cartridge is movably attached to the first housing such that the medication cartridge can be moved from an inactive position in which the needle is not aligned with the opening for passing through the opening to an active position in which the needle is aligned with the opening for passing through the opening.

In accordance with yet a further embodiment of the device herein described, the first housing and the second housing are dimensioned such that when the first housing and the second housing are in the first orientation, the device can be worn as a bracelet on a wrist of the subject.

In accordance with still a further embodiment of the present invention, there is provided a medication cartridge for a device for injecting a medication in a subject, the cartridge comprising: a chamber containing the medication; a hollow needle attached to the chamber, the hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle, the proximal end of the needle being in fluid communication with the chamber; an injection mechanism for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle; and a mounting structure for supporting the chamber, a section of the mounting structure being dimensioned for attachment at least partially within a housing of the device.

In accordance with yet still a further embodiment of the medication cartridge herein described, the injection mechanism comprises: a plunger slidingly arranged in the chamber for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from a first retracted position to a second extended position; a spring engaging the plunger and a portion of the cartridge, the spring biasing the plunger toward the needle, the spring having a first working length in which the plunger is in a ready position before moving the medication from the chamber and before moving the needle from the first position to the second position, and the spring having a second working length in which the plunger is in an activated position in which the plunger has moved the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and the plunger has moved the needle from the first position to the second position; and a releasable catch for maintaining the plunger in the ready position until the catch is released.

In another aspect of the medication cartridge herein described, the plunger engages and moves the chamber when the spring moves from the first working length to the second working length.

In yet another aspect of the medication cartridge herein described, the section of the mounting structure is disk-shaped for engaging a circular opening of the housing of the device.

In still another aspect of the medication cartridge herein described, the chamber is slidingly arranged in a cylinder, and the chamber has ready position before moving the medication from the chamber and an activated position in which the medication has moved from the chamber.

In yet still another aspect of the medication cartridge herein described, the medication is epinephrine. In a further aspect of the present invention, there is provided a method for injecting a medication in a subject, the method comprising: (a) providing an injection device including (i) a first housing, (ii) a second housing rotatably attached to the first housing, and (iii) a medication cartridge attached to the first housing, the medication cartridge including a chamber for containing the medication, the medication cartridge including a hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle, the proximal end of the needle being in fluid communication with the chamber; (b) moving the first housing and the second housing from a first orientation of the first housing and the second housing in which medication cannot be moved from the chamber through the fluid path of the needle and out of the distal end of the needle into a second orientation in which medication can be moved from the chamber through the fluid path of the needle and out of the distal end of the needle, thereby activating a trigger mechanism; (c) locating the device against an injection area of the subject; and (d) pressing the trigger mechanism for initiating movement of the distal end of the needle towards the injection area of the subject and for initiating movement of the medication from the chamber through the fluid path of them needle and out of the distal end of the needle.

In yet a further aspect of the method herein described, the step of moving the first housing and the second housing comprises rotating the first housing and the second housing 180° around their axis.

In still a further aspect of the method herein described, the step of moving the first housing and the second housing comprises rotating the first housing through an axis of the first housing with respect to the second housing by twisting. These and other features, aspects, and advantages of the present invention will become better understood upon consideration of the following detailed description, drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a top view of an automatic injection device according to one example embodiment of the invention wherein the device is in a first (closed) orientation.

Figure 2 is a top view of the automatic injection device of Figure 1 in a second (open) orientation.

Figure 3 is a cross-sectional detailed view of the automatic injection device taken along line 3-3 of Figure 2. Figure 4 is a cross-sectional detailed view of the medication cartridge of the automatic injection device taken along line 4-4 of Figure 2.

Figure 5 is a cross-sectional detailed view, similar to Figure 4, of the medication cartridge of another example embodiment of the invention.

Figure 6 is a cross-sectional detailed view, similar to Figure 3, of the example embodiment of Figure 5.

Figure 7 is a cross-sectional detailed view, similar to Figure 4, of the medication cartridge of yet another example embodiment of the invention. Figure 8 is a perspective view of a user activating an automatic injection device according to one example embodiment of the invention.

Like reference numerals will be used to refer to like parts from Figure to Figure in the following description of the drawings. DETAILED DESCRIPTION OF THE INVENTION

Looking first at Figures 1-4, there is shown a first example embodiment of an automatic injection device 10 according to the invention. The device 10 can be used for injecting a medication in a subject. Non-limiting examples of medications include epinephrine, antidotes to a nerve agent, beta blockers, blood thinners, nitroglycerine, antihistamines, insulin, and analgesics.

When the two housings of the device of the present invention are referred to as "attached", it is understood that the housings are not separated by a user and are considered, substantially and/or permanently attached to each other. The housing may also be attached to each other by a mechanism which is not removable. When the housings are referred to as being "rotatably attached", the housings are attached by a mechanism that allow the first housing to be rotated through an axis of the housing with respect to the second housing, for example, by twisting. The feature through which this rotatable attachment will typically occur is the hinge 21.

The device 10 includes a first arcuate tubular housing 12 having an outer wall 13 with an outer surface 14. The outer wall 13 of the first housing 12 defines an interior space 15 of the first housing 12, and the outer wall 13 has an opening 16 that extends from the interior space 15 of the first housing 12 to the outer surface 14. The opening 16 is covered with a puncturable seal 17.

The device 10 includes a second arcuate tubular housing 18 having an outer wall 19 that defines an interior space 20 of the second housing 18. A hinge 21 connects the first housing 12 and the second housing 18 such that the first housing 12 can be rotated trough the axis of the arcuate tube of the housing with respect to the second housing 18 by twisting. In one non-limiting form, the hinge 21 can comprise one or more projections on the end of the first housing 12 or the second housing 18 that move in a groove in the end of the first housing 12 or the second housing 18. The end of the second housing 18 opposite the hinge 21 terminates in a cap 22. The end 23 of the first housing 12 opposite the hinge 21 terminates in a medication cartridge 24 which will be explained further below. In another non-limiting form the hinge can rotate the housings 12 and 18 180° around their axes.

In Figure 1 , the device 10 is shown in a first closed orientation wherein the first housing 12 and the second housing 18 form a closed curve with a circular perimeter in top view. The first housing 12 forms less than half of the length of the perimeter. In other words, the first housing 12 has an arc of less than 180 degrees. When the first housing 12 and the second housing 18 are in the first orientation of Figure 1 , the first housing 12 and the second housing 18 form a toroid wherein a surface of the toroid is a torus. However, the shape of the first housing 12 and the second housing 18 can be varied from the non-limiting form of Figure 1. For example, when the first housing 12 and the second housing 18 are in the first orientation, the first housing 12 and the second housing 18 may form a perimeter in the shape of an oval or a polygon in top view. Non-limiting polygonal shapes include triangle, quadrilateral, pentagon, hexagon, heptagon, and octagon. In another example form, when the first housing 12 and the second housing 18 are in the first orientation, the first housing 12 and the second housing 18 define an at least partially enclosed interior space. In other words, there is a gap of some size between the medication cartridge 24 attached to the first housing 12 and the cap 22 inserted in the second housing 18. In Figure 2, the device 10 is shown in a second open orientation wherein the second housing 18 has been rotated 180 degrees from the first orientation of Figure 1 to create a generally S-shaped perimeter in top view for the first housing 12 and the second housing 18.

In another embodiment not illustrated, the medication cartridge 24 may be optionally placed in either the first or second housing 12,18 where the opening 16 and puncturable seal 17 would also be placed.

The first housing 12 and the second housing 18 can be formed from a variety of materials such as polymeric materials, metallic materials, ceramic materials, and composites thereof. In one example form, the first housing 12 and the second housing 18 are formed from a polymeric material such a polyolefin, a polyester, or a polystyrene. The polymeric material may be transparent, or may include a pigment such that the first housing 12 and the second housing 18 are translucent or opaque. Referring now to Figure 4, the end 23 of the first housing 12 opposite the hinge 21 terminates in the medication cartridge 24. The medication cartridge 24 includes a mounting structure 25 having a cap 26 and a cylinder 27 attached to the cap 26. The cap 26 allows the medication cartridge 24 to rotate with respect to the end 23 of the first housing 12. In one non-limiting form, the cap 26 can comprise one or more projections that move in a groove in the end 23 of the first housing 12 for rotation.

Still referring to Figure 4, a plunger 28 is slidingly arranged in the cylinder 27 of the medication cartridge 24. The plunger 28 has an upper cylindrical pocket 29 containing a compression spring 30 that bears against a wall 31 of the cylinder 27. The plunger 28 includes a central shaft 32 that terminates in a plunger head 33. A chamber 34 is also slidingly arranged in the cylinder 27 of the medication cartridge 24. The chamber 34 has a cylindrical outer wall 35 that defines an interior space 36 that contains a medication 37. The chamber 34 has a flange 39 that extends outwardly at an open end 40 of the chamber 34. A medication exit port 41 is provided at a closed end of the chamber 34. A hollow needle 43 having a proximal end 44 and a distal end 45 is attached to the medication exit port 41 of the chamber 34. The hollow needle 43 defines a fluid path 46 from the medication exit port 41 at the proximal end 44 of the hollow needle 43 to the distal end 45 of the hollow needle 43. The distal end 45 of the hollow needle 43 terminates in a sharp point as is known in the hypodermic needle art. Optionally, the needle 43 can be covered with a sheath before actuation of the device 10. An aperture 48 is provided in a side wall of the cylinder 27 of the medication cartridge 24. A catch pin 49 is movable within the aperture 48 for initiating movement of the plunger 28 as explained below.

Looking at Figures 2-4, the elements of an actuator of the automatic injection device 10 are shown. The actuator 51 includes a slide switch 52 that is slidably mounted in the outer wall 19 of the second housing 18. The actuator 51 further includes a first wire form 54 having an angled proximal end 55, an elongated intermediate section 56, and an angled distal end 57. The proximal end 55 of the first wire form 54 engages the slide switch 52. The elongated intermediate section 56 of the first wire form 54 translates in support bearings 58 that guide the first wire form 54. The actuator 51 further includes a second wire form 60 having an angled proximal end 61 , an elongated intermediate section 62, and a looped distal end 63. The second wire form 60 translates in support bearings 64 that guide the second wire form 60. Alternatively, all or some of the elements of the actuator of the automatic injection device 10 can be mounted in the first housing 12. Having described the components of the first example embodiment of an automatic injection device 10 in Figures 1-4, operation of the automatic injection device 10 can be described further. The automatic injection device 10 can be worn on a human subject's wrist as a bracelet when in the first orientation of Figure 1. When the subject wishes to administer a dose of the medication 37, the second housing 18 is rotated 180 degrees from the first orientation of Figure 1 to create the generally S-shaped second orientation of Figure 2.

When the device 10 is in the generally S-shaped second orientation of Figure 2, the angled distal end 57 of the first wire form 54 is linked in mechanical communication with the angled proximal end 61 of the second wire form 60 as shown in Figures 2 and 3. As a result, when a user presses on the slide switch 52, the slide switch 52 and the angled distal end 57 of the first wire form 54 move in direction A. Because the angled distal end 57 of the first wire form 54 is linked with the angled proximal end 61 of the second wire form 60, the second wire form 60 also moves in direction A. When the device 10 is twisted out of the generally S-shaped second orientation of Figure 2, the link between the first wire form 54 and the second wire form 60 is broken and movement of the slide switch 52 does not move the second wire form 60 in direction A. It can be appreciated therefore that movement of the second wire form 60 is effectuated only in the generally S-shaped second orientation of Figure 2. Although the first housing 12 and the second housing 18 are rotated 180 degrees in the example embodiment of the automatic injection device 10 in order to mechanically link the angled distal end 57 of the first wire form 54 with the angled proximal end 61 of the second wire form 60, it can be appreciated that the first wire form 54 and the second wire form 60 can be arranged at different relative positions in the device 10 such that degrees of rotation other than 180 degrees can be used to mechanically link the angled distal end 57 of the first wire form 54 with the angled proximal end 61 of the second wire form 60.

Looking at Figure 4, the device 10 is provided with the medication cartridge 24 installed in the end 23 of the first housing 12. In Figure 4, the medication cartridge 24 is shown with the needle 43 in a first position in which the distal end 45 of the needle 43 is within the wall 13 of the first housing 12. In Figure 4, the spring 30 is shown at a first compressed working length in which the plunger 28 and chamber 34 are in a ready position. An end of the catch pin 49 is located underneath the pocket 29 of the plunger 28. This keeps the spring 30 at the first compressed working length in which the plunger 28 and the chamber 34 are in the ready position. The medication cartridge 24 is rotatably attached to the first housing 12 such that the medication cartridge 24 can be moved from an inactive position in which the needle 43 is not aligned with the opening 16 for passing through the opening 16 to an active position in which the needle 43 is aligned with the opening 16 for passing through the opening 16. In Figure 4, the medication cartridge 24 is shown in the active position in which the needle 43 is aligned with the opening 16 for passing through the opening 16. Suitable markings can be placed on the cap 26 of the medication cartridge 24 and the end 23 of the first housing 12 to signal to the user the relative rotational positioning of the cap 26 and the end 23 of the first housing 12. For example, lining up a marking on the cap 26 of the medication cartridge 24 and another marking on the end 23 of the first housing 12 can indicate that the medication cartridge 24 is in the active position in which the needle 43 is aligned with the opening 16 for passing through the opening 16. The feature of active and inactive positions for the medication cartridge 24 is advantageous as the inactive position can prevent the needle from exiting the first housing 12 upon accidental misfiring, that is, the wall 13 of the first housing 12 will block the needle 43.

Looking at Figure 4, movement of the second wire form 60 in direction A triggers injection of the medication 37 as follows. When the medication cartridge 24 is in the active position in which the needle 43 is aligned with the opening 16 for passing through the opening 16, the looped distal end 63 of the second wire form 60 engages the catch pin 49 as shown in Figure 4. Movement of the second wire form 60 in direction A also moves the catch pin 49 in direction A. Due to movement of the catch pin 49 in direction A, the end of the catch pin 49 will no longer be located underneath the pocket 29 of the plunger 28. As a result, the spring 30 will move towards a second extended working length and cause the plunger 28 to move in direction B in Figure 4. The plunger head 33 will then force the medication 37 from the medication exit port 41 , through the proximal end 44 of the hollow needle 43 and through the distal end 45 of the hollow needle 43. Also, the upper cylindrical pocket 29 of the plunger 28 will engage the flange 39 of the plunger 28 and move the plunger 28 to an activated position in which the needle 43 is in a second position in which the distal end 45 of the needle 43 extends outward beyond the outer surface 14 of the wall 13 of the first housing 12.

The distance that the needle 43 extends outward beyond the outer surface 14 of the wall 13 of the first housing 12 can be controlled by appropriate sizing of the plunger 28 and the chamber 34 and appropriate positioning of the plunger 28 and the chamber 34 in the cylinder 27. For example, the needle 43 can extend outward beyond the outer surface 14 of the wall 13 of the first housing 12 from 0.1 to 40 millimeters. This provides for injection at the desired penetration depth in the subject. The amount of medication injected can be controlled by appropriate sizing of the plunger 28 and the chamber 34. For example, 0.3 and 0.15 milligrams of epinephrine can be suitable when epinephrine is the medication. The needle 43 can be oriented in various positions. The needle can be oriented in the housing 12 so that when the needle 43 is in the second position, the needle 43 can extend outward beyond the outer surface 14 of the wall 13 of the first housing 12 such that the needle 43 forms an oblique angle with the outer surface 14 of the wall 13 of the first housing 12. The needle can be oriented in the housing 12 so that when the needle 43 is in the second position, the needle 43 can extend outward beyond the outer surface 14 of the wall 13 of the first housing 12 such that the needle 43 forms a right angle with the outer surface 14 of the wall 13 of the first housing 12. Optionally, the needle 43 can be curved.

Figure 8 shows the use of the automatic injection device 10 by a human 67. The outer wall 13 of the first housing 12 is dimensioned to conform to the curves of the vastus lateralis muscle of the thigh 69 enabling the human 67, or first responder, to easily target an injection area in the thigh 69. As detailed above, the automatic injection device 10 can be worn on the human's wrist as a bracelet when in the first orientation of Figure 1. When the human 67 wishes to administer a dose of the medication 37, the second housing 18 is rotated 180 degrees from the first orientation of Figure 1 to create the generally S-shaped second orientation of Figures 2 and 8. The human 67 grasps the second housing 18 with their hand 68, and the first housing 12 is placed over the thigh 69 with the opening 16 in the outer wall 13 of the first housing 12 facing the thigh 69. When the human 67 presses on the slide switch 52, the needle 43 extends outward beyond the outer surface 14 of the wall 13 of the first housing 12 as explained above and into a muscle of the thigh 69 of the human 67 delivering a dose of the medication. Alternatively, the outer wall 13 of the first housing 12 can be dimensioned to conform to the curves of the deltoid muscle of the shoulder enabling the human 67, or first responder, to easily target an injection area in the shoulder. In Figures 5-6, the elements of an alternative actuator 71 for a second embodiment of an automatic injection device 10a are shown. The actuator 71 includes an electrical switch in place of the slide switch 52 of the embodiment of Figures 1-4. The electrical switch is in electrical communication with a source of electrical current (e.g., a battery) and with a first lead wire 74 having an electrical contact 77 at its distal end. The actuator 71 also includes a second lead wire 80 having an electrical contact 81 at its proximal end. The second lead wire 80 is in electrical communication with a transducer device 86 at its distal end. The transducer device 86 can be a solenoid based device.

The device 10a is provided with a medication cartridge 24 as in the embodiment of Figures 1-4. However, the medication cartridge 24 includes an alternative catch pin 87 that is located underneath the pocket 29 of the plunger 28. The catch pin 87 keeps the spring 30 at the first compressed working length in which the plunger 28 and the chamber 34 are in the ready position. When the device 10a is in the generally S-shaped second orientation as in Figure 2, the electrical contact 77 is linked in electrical communication with electrical contact 81 as shown in Figure 6. As a result, when a user presses on the electrical switch, current is provided to energize the transducer device 86. This causes the catch pin 87 to move in direction C such that the end of the catch pin 87 will no longer be located underneath the pocket 29 of the plunger 28. As a result, the spring 30 will move towards a second extended working length and cause the plunger 28 to move in direction B in Figure 5. The plunger head 33 will then force the medication 37 from the medication exit port 41 , through the proximal end 44 of the hollow needle 43 and through the distal end 45 of the hollow needle 43. Also, the upper cylindrical pocket 29 of the plunger 28 will engage the flange 39 of the plunger 28 and move the plunger 28 to an activated position in which the needle 43 is in a second position in which the distal end 45 of the needle 43 extends outward beyond the outer surface 14 of the wall 13 of the first housing 12.

In Figure 7, the elements of an alternative actuator 91 for a third embodiment of an automatic injection device 10b are shown. The actuator 91 includes an electrical switch, a source of electrical current (e.g., a battery), a first lead wire having an electrical contact at its distal end, and a second lead wire 80b having an electrical contact at its proximal end as in the embodiment of Figures 5-6. The second lead wire 80b is in electrical communication with an electrically controllable valve 92.

Still referring to Figure 7, the device 10b is provided with a medication cartridge 24b similar to the medication cartridge 24 in the embodiment of Figures 1-4. However, the medication cartridge 24b does not include a spring 30 as in the medication cartridge 24 in the embodiment of Figures 1-4. Instead, the wall 31 b of the cylinder 27b of the medication cartridge 24b includes an opening 93 that provides a fluid path from the valve 92 to the upper cylindrical pocket 29 of the plunger 28. The medication cartridge 24b has a cap 26b including a source 94 of compressed gas. The source 94 of compressed gas is in fluid communication with the valve 92 by way of fluid line 95.

When the device 10b is in the generally S-shaped second orientation as in Figure 2, the electrical contact of the first lead wire is linked in electrical communication with the second lead wire 80b. As a result, when a user presses on the electrical switch, current is provided to open the valve 92. This causes the compressed gas to flow into the upper cylindrical pocket 29 and cause the plunger 28 to move in direction B in Figure 7. The plunger head 33 will then force the medication 37 from the medication exit port 41 , through the proximal end 44 of the hollow needle 43 and through the distal end 45 of the hollow needle 43. Also, the upper cylindrical pocket 29 of the plunger 28 will engage the flange 39 of the plunger 28 and move the plunger 28 to an activated position in which the needle 43 is in a second position in which the distal end 45 of the needle 43 extends outward beyond the outer surface 14 of the wall 13 of the first housing 12.

Other variations of the device of Figure 7 are possible. For example, the source of compressed gas can be used for needleless injection of the medication. Other variations of the medication cartridge 24 are possible. The medication cartridge 24 can have a first neutral position in which a section of the medication cartridge 24 closes off the opening 16 in the first housing. The medication cartridge 24 can be rotated 120 degrees to a first position in which a dose of medication can be injected from a first chamber through a first needle as explained above. The medication cartridge 24 can then be rotated another 120 degrees to a second position in which a second dose of medication can be injected from a second chamber through a second needle in the manner as explained above. Thus, the invention provides an automatic device for injecting medication in a subject.

Although the invention has been described in considerable detail with reference to certain embodiments, one skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the scope of the appended claims should not be limited to the description of the embodiments contained herein.

Claims

CLAIMS:

1. A device for injecting a medication in a subject, the device comprising: a first housing; a second housing attached to the first housing; a medication cartridge including a chamber for containing the medication and including a hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle, the proximal end of the needle being in fluid communication with the chamber, the medication cartridge being dimensioned for attachment at least partially within the first housing; an injection mechanism for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from a first position in which the distal end of the needle is within a wall of the first housing and a second position in which the distal end of the needle extends outward beyond an outer surface of the wall of the first housing; and an actuator which can be placed in electrical and/or mechanical communication with the injection mechanism, wherein the first housing and the second housing can be moved from a first orientation of the first housing and the second housing in which the actuator cannot be placed in electrical or mechanical communication with the injection mechanism to a second orientation of the first housing and the second housing in which the actuator can be placed in electrical or mechanical communication with the injection mechanism, and wherein when the first housing and the second housing are in the second orientation, the actuator can be actuated for initiating movement of the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for initiating movement of the needle from the first position to the second position.

2. The device of claim 1 , wherein when the first housing and the second housing are in the first orientation, the first housing and the second housing form a closed curve.

3. The device of claim 1 , wherein when the first housing and the second housing are in the first orientation, the first housing and the second housing form a polygon.

4. The device of claim 1 , wherein when the first housing and the second housing are in the first orientation, the first housing and the second housing form a perimeter having a length, and the first housing forms less than half of the length of the perimeter.

5. The device of claim 1 , wherein when the first housing and the second housing are in the first orientation, the first housing and the second housing form a toroid.

6. The device of claim 5, wherein a surface of the toroid is a torus.

7. The device of claim 1 , wherein the wall of the first housing is a side wall of the first housing such that the needle extends laterally from an axis of the first housing outward beyond an outer surface of the side wall of the first housing.

8. The device of claim 1 , wherein the injection mechanism comprises: a plunger slidingly arranged in the chamber for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from the first position to the second position; a spring engaging the plunger and a portion of the cartridge, the spring biasing the plunger toward the needle, the spring having a first working length in which the plunger is in a ready position before moving the medication from the chamber and before moving the needle from the first position to the second position, and the spring having a second working length in which the plunger is in an activated position in which the plunger has moved the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and the plunger has moved the needle from the first position to the second position; and a releasable catch for maintaining the plunger in the ready position until the actuator is actuated, wherein actuating the actuator releases the catch and thereby allows the spring to move the plunger to the activated position.

9. The device of claim 8, wherein when the first housing and the second housing are in the second orientation and the actuator is actuated, the actuator is mechanically linked to the catch for releasing the catch.

10. The device of claim 8, wherein when the first housing and the second housing are in the second orientation and the actuator is actuated, the actuator is electromechanically linked to the catch for releasing the catch.

11. The device of claim 1 , wherein the injection mechanism comprises: a plunger slidingly arranged in the chamber for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from the first position to the second position; a spring engaging the plunger and a portion of the cartridge, the spring biasing the plunger away the needle, the spring having a first working length in which the plunger is in a ready position before moving the medication from the chamber and before moving the needle from the first position to the second position, and the spring having a second working length in which the plunger is in an activated position in which the plunger has moved the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and the plunger has moved the needle from the first position to the second position; a source of compressed fluid; and a fluid conduit in fluid communication with the source of compressed fluid and a section of the chamber on a side of the plunger opposite the needle, wherein actuating the actuator releases compressed fluid into the section of the chamber thereby moving the plunger to the activated position.

12. The device of claim 11 , wherein the fluid conduit includes a valve between the source of compressed fluid and the section of the chamber, and when the first housing and the second housing are in the second orientation and the actuator is actuated, the actuator is electrically or mechanically linked to the valve such that the valve releases compressed fluid into the section of the chamber.

13. The device of claim 1 , wherein the first housing includes an opening in the wall of the first housing, and the needle passes through the opening when the needle moves from the first position to the second position.

14. The device of claim 13, wherein the opening is covered with a seal, and the needle punctures through the seal when the needle moves from the first position to the second position.

15. The device of claim 13, wherein the medication cartridge is movably attached to the first housing such that the medication cartridge can be moved from an inactive position in which the needle is not aligned with the opening for passing through the opening to an active position in which the needle is aligned with the opening for passing through the opening.

16. The device of claim 1 , wherein the first housing and the second housing are dimensioned such that when the first housing and the second housing are in the first orientation, the device can be worn as a bracelet on a wrist of the subject.

17. A medication cartridge for a device for injecting a medication in a subject, the cartridge comprising: a chamber containing the medication; a hollow needle attached to the chamber, the hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle, the proximal end of the needle being in fluid communication with the chamber; an injection mechanism for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle; and a mounting structure for supporting the chamber, a section of the mounting structure being dimensioned for attachment at least partially within a housing of the device.

18. The medication cartridge of claim 17, wherein the injection mechanism comprises: a plunger slidingly arranged in the chamber for moving the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and for moving the needle from a first retracted position to a second extended position; a spring engaging the plunger and a portion of the cartridge, the spring biasing the plunger toward the needle, the spring having a first working length in which the plunger is in a ready position before moving the medication from the chamber and before moving the needle from the first position to the second position, and the spring having a second working length in which the plunger is in an activated position in which the plunger has moved the medication from the chamber through the fluid path of the needle and out of the distal end of the needle and the plunger has moved the needle from the first position to the second position; and a releasable catch for maintaining the plunger in the ready position until the catch is released.

19. The medication cartridge of claim 18, wherein the plunger engages and moves the chamber when the spring moves from the first working length to the second working length.

20. The medication cartridge of claim 17, wherein the section of the mounting structure is disk-shaped for engaging a circular opening of the housing of the device.

21. The medication cartridge of claim 17, wherein the chamber is slidingiy arranged in a cylinder, and the chamber has ready position before moving the medication from the chamber and an activated position in which the medication has moved from the chamber.

22. The medication cartridge of claim 17, wherein the medication is epinephrine.

23. A method for injecting a medication in a subject, the method comprising:

(a) providing an injection device including (i) a first housing, (ii) a second housing rotatably attached to the first housing, and (iii) a medication cartridge attached to the first housing, the medication cartridge including a chamber for containing the medication, the medication cartridge including a hollow needle defining a fluid path from a proximal end of the needle to a distal end of the needle, the proximal end of the needle being in fluid communication with the chamber;

(b) moving the first housing and the second housing from a first orientation of the first housing and the second housing in which medication cannot be moved from the chamber through the fluid path of the needle and out of the distal end of the needle into a second orientation in which medication can be moved from the chamber through the fluid path of the needle and out of the distal end of the needle, thereby activating a trigger mechanism;

(c) locating the device against an injection area of the subject; and

(d) pressing the trigger mechanism for initiating movement of the distal end of the needle towards the injection area of the subject and for initiating movement of the medication from the chamber through the fluid path of them needle and out of the distal end of the needle.

24. The method of claim 23, wherein the step of moving the first housing and the second housing comprises rotating the first housing and the second housing 180° around their axis.

25. The method of claim 23, wherein the step of moving the first housing and the second housing comprises rotating the first housing through an axis of the first housing with respect to the second housing by twisting.