Needle actuator assembly for a drug delivery system

Abstract

To provide a drug delivery system including a needle actuator assembly.SOLUTION: A needle actuator assembly 18 for a drug delivery system 10 includes a needle actuator body having a guide surface, a needle shuttle 102 having a cam surface, with the needle shuttle moveable along a vertical axis between a first position and a second position. The needle shuttle is configured to move between the first and second positions through engagement between the guide surface of the needle actuator body and the cam surface of the needle shuttle. The assembly further including a needle received by the needle shuttle.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] This application claims priority to U.S. Provisional Application No. 62 / 347,921, filed Jun. 9, 2016, and U.S. Patent Application No. 15 / 616,212, filed Jun. 7, 2017, each of which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to infusion devices and methods for delivering fluids into a patient's body by injection.

Background Art

[0003] Various types of automatic infusion devices have been developed to enable drug solutions and other liquid therapeutic preparations to be administered by untrained persons or self-administered. Generally, these devices include a reservoir pre-filled with a liquid therapeutic preparation and some type of automatic needle injection mechanism that can be triggered by a user. When the amount of fluid or drug to be administered is less than a fixed amount, such as 1 mL, an autoinjector is typically used, which typically has an infusion time of about 10 to 15 seconds. When the amount of fluid or drug to be administered exceeds 1 mL, the infusion time generally becomes longer, resulting in difficulty in maintaining contact between the device and the target site on the patient's skin. Further, as the amount of drug to be administered increases, it is desirable to increase the infusion time. A conventional method for drugs that are slowly infused into a patient is to start an IV and slowly infuse the drug into the patient's body. Such procedures are typically performed in a hospital or outpatient setting.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] Certain devices enable self - injection in a home setting and can gradually inject a liquid therapeutic formulation into a patient's skin. In some cases, these devices are small enough (in both height and overall size) to be "worn" by the patient while the liquid therapeutic formulation is being injected into the patient's body. These devices typically include a pump or other type of discharge mechanism that causes the liquid therapeutic formulation to flow from a reservoir into a hypodermic needle. Such devices also typically include a valve or flow control mechanism to enable the liquid therapeutic preparation to begin flowing at an appropriate time and a trigger mechanism to initiate the injection.

MEANS FOR SOLVING THE PROBLEMS

[0006] In one aspect, a needle actuator assembly for a drug delivery system includes a needle actuator body having a guide surface and a needle shuttle having a cam surface, the needle shuttle being movable along a vertical axis between a first position and a second position. The needle shuttle is configured to move between the first position and the second position by engagement of the guide surface of the needle actuator body and the cam surface of the needle shuttle. The assembly further includes a needle received by the needle shuttle.

[0007] The needle shuttle may include a biasing member configured to move the needle shuttle from a first position to a second position, and the guide surface of the needle actuator body disengages from the cam surface of the needle shuttle. The assembly may include a guide post, and the needle shuttle moves along the guide post. The guide post may be linear. The cam surface of the needle shuttle includes a first cam member and a second cam member spaced from the first cam member, and there, the guide surface is non-linear and includes a first side surface and a second side surface located on the side opposite the first side surface. The second cam member of the needle shuttle may be configured to engage the second side surface of the guide surface, move the needle shuttle from the first position to the second position, and may be configured to engage the first side surface of the guide surface. The first cam member of the needle shuttle moves the needle shuttle from the second position to the first position.

[0008] In a further aspect, a drug delivery system for injecting a drug includes a housing and a needle actuator assembly housed within the housing. The needle actuator assembly includes a needle actuator body having a guide surface. The needle actuator body is movable between a first position and a second position, and the needle shuttle has a cam surface. The needle shuttle is movable along a vertical axis between the first position and the second position, and the needle shuttle is configured to move between the first position and the second position through the engagement of the guide surface of the needle actuator body and the cam surface of the needle shuttle. The needle actuator assembly also includes a needle received by the needle shuttle. The system further includes a button actuator at least partially received by the housing, and the movement of the button actuator is configured to move the needle actuator body from the first position to the second position. The movement of the needle actuator body from the first position to the second position is configured to effect the movement of the needle shuttle from the first position to the second position.

[0009] The needle shuttle may include a biasing member configured to move the needle shuttle from a first position to a second position, and the guide surface of the needle actuator body disengages from the cam surface of the needle shuttle. The system includes a guide post extending from the housing, and the needle shuttle moves along the guide post. The guide post may extend substantially perpendicular to the housing.

[0010] The system may include a pad configured to engage the needle when the needle actuator is in the second position. The pad may be received by a pad arm having a cam surface configured to engage a corresponding cam track of the housing to move the pad under the needle.

[0011] The above and other features and advantages of the present disclosure, and the manner of achieving them, will be more readily understood by reference to the following description of the embodiments of the disclosure in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0012]

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DETAILED DESCRIPTION OF THE INVENTION

[0013] Corresponding reference numerals indicate corresponding parts throughout the several views. The examples described herein are illustrative of exemplary aspects of the present disclosure and such examples should not be construed as limiting the scope of the present disclosure in any way.

[0014] The following description is provided to enable a person of ordinary skill in the art to make and use the described embodiments, which are contemplated for carrying out the present invention. However, various changes, equivalents, modifications, and alternatives will be readily apparent to those of ordinary skill in the art. Any and all such changes, modifications, equivalents, and alternatives are intended to fall within the spirit and scope of the present invention.

[0015] For the purposes of the following description, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives thereof will be related to the present invention as oriented in the drawings. However, it should be understood that the present invention may assume various alternative modifications, unless specifically stated to the contrary. Also, it should be understood that the specific devices shown in the accompanying drawings and described in the following specification are merely exemplary embodiments of the present invention. Accordingly, the specific dimensions and other physical characteristics related to the embodiments disclosed herein should not be considered limiting.

[0016] Referring to FIGS. 1-16, a drug delivery system 10 according to one aspect of the present invention includes a drive assembly 12, a container 14, a valve assembly 16, and a needle actuator assembly 18. The drive assembly 12, the container 14, the valve assembly 16, and the needle actuator assembly 18 are at least partially disposed within a housing 20. The housing 20 includes a top 22 and a bottom 24, although other suitable arrangements for the housing 20 may be utilized. In one aspect, the drug delivery system 10 is a syringe device configured to be worn or secured to a user and deliver a predetermined dose of a drug provided within the container 14 by injection into the user. The system 10 may be utilized to deliver a "bolus injection" in which the drug is delivered within a set time. The drug may be delivered over a period of up to 45 minutes, although other suitable injection volumes and durations may be utilized. The bolus administration or delivery may be performed with or without speed control. The system 10 may deliver the drug to the user at a constant pressure with a variable speed. The general operation of the system 10 is described below with reference to FIGS. 1-16, and the drive assembly 12, the needle actuator assembly 18, and other features of the system 10 are discussed below in connection with FIGS. 17-93.

[0017] Referring again to FIGS. 1 - 16, the system 10 is configured to operate via engagement of an activation button 26 by a user, which causes the needle 28 of the needle actuator assembly 18 to pierce the user's skin, the operation of the drive assembly 12 to place the needle 28 in fluid communication with the container 14, and the release of a fluid or drug from the container 14, and the withdrawal of the needle 28 to be completed after drug injection. The general operation of the drug delivery system is shown and described in Patent Documents 1 and 2, the entireties of which are incorporated herein by reference. The housing 20 of the system 10 includes an indicator window 30 for viewing an indicator arrangement 32 configured to provide an indication to the user regarding the state of the system 10, and a container window 31 for viewing the container 14. The indicator window 30 can be a magnifying lens for providing a clear view of the indicator arrangement 32. The indicator arrangement 32 moves with the needle actuator assembly 18 during use of the system 10 and indicates the pre - use state, use state, and post - use state of the system 10. The indicator arrangement 32 provides a visual indication regarding status, but as an alternative or additional indicator, provides other suitable indications such as auditory or tactile.

[0018] Referring to FIGS. 4 - 6, between the pre - use positions of the system 10, the container 14 is spaced from the drive assembly 12 and the valve assembly 16, and the needle 28 is in the retracted position. As shown in FIGS. 7 - 9, during the first actuation of the system 10, the drive assembly 12 engages the container 14 and moves the container 14 toward the valve assembly 16, which is configured to pierce the closure 36 of the container 14 and place the drug within the container 14 in fluid communication with the needle 28 via a tube (not shown) or other suitable arrangement. The drive assembly 12 is configured to engage the stopper 34 of the container 14, which will first move the entire container 14 into engagement with the valve assembly 6 due to the incompressibility of the fluid or drug within the container 14. The first actuation of the system 10 is caused by the user engaging the actuation button 26, which releases the needle actuator assembly 18 and the drive assembly 12 as will be described in detail below. During the first actuation, the needle 28 is still in the retracted position and is attempting to move to the extended position for injection into the user of the system 10.

[0019] As shown in FIGS. 10 - 12, between the use positions of the system 10, the needle 28 is at least partially in the extended position outside the housing 20, and the drive assembly 12 moves the stopper 34 within the container 14 to deliver the drug from the container 14 through the needle 28 to the user. In the use position, the valve assembly 16 has already pierced the closure 36 of the container 14 and placed the container 14 in fluid communication with the needle 28, which also enables the drive assembly 12 to move the stopper 34 relative to the container 14 since fluid can be dispensed from the container 14. In the post - use position of the system 10, shown in FIGS. 13 - 15, the needle 28 is in the retracted position and engages the pad 38 to seal the needle 28 and prevent any residual flow of fluid or drug from the container 14. The container 14 and the valve assembly 16 can be the container 14 and the valve assembly 16 shown and described in Patent Document 3, which is hereby incorporated by reference in its entirety.

[0020] Referring to FIGS. 15A - 15C, the pad 38 is biased into the needle when the needle actuator body 96 moves from the use position to the post - use position. Specifically, the pad 38 is received by a pad arm 122 having a cam surface 124 that cooperates with a cam track 126 on the bottom 24 of the housing 20. The pad arm 122 is connected to the needle actuator body 96 via a torsion bar 128. The cam surface 124 is configured to engage the cam track 126 and deflect the pad arm 122 downward, whereby the pad 38 passes under the needle 28 before being biased upward into the needle 28. The torsion bar 128 allows the pad arm 122 to twist about the pivot of the needle actuator body 96. The pad 38 can be press - fit into an opening of the pad arm 122, although other suitable arrangements for securing the pad 38 can be utilized.

[0021] Referring to FIGS. 1-33, a drive assembly 12 according to one aspect of the present invention is shown. As described above, the drive assembly 12 is configured to move the container 14, pierce the closure 36 of the container 14, and move the stopper 34 within the container 14 to dispense fluid or a drug from the container 14. The drive assembly 12 shown in FIGS. 17-33 is configured to engage and cooperate with a spacer assembly 40 received by the stopper 34 of the container 14. The spacer assembly 40 includes a spacer 42 and a spacer holder 44. The spacer holder 44 is received by the stopper 34, and the spacer 42 is received by the spacer holder 44. The spacer holder 44 includes a first threaded portion 46 that engages a corresponding threaded portion of the stopper 34, although other suitable configurations may be utilized. The spacer 42 also includes a threaded portion 48 that engages a corresponding second threaded portion 50 of the spacer holder 44 to secure the spacer 42 to the spacer holder 44, although other suitable configurations may be utilized. The drive assembly 12 is configured to dispense within a range of predetermined fill volumes of the container 14 while maintaining the functional characteristics of the system 10 described above, including, but not limited to, retracting the needle 28 after the end of the dose and providing an indication of the state of the system 10, while also minimizing a sudden engagement of the stopper 34 by the drive assembly 12. The drive assembly 12 is configured to dispense within a range of multiple separate fill volumes by utilizing spacers 42 of multiple sizes. In one aspect, a range of 12 fill volumes and 12 spacer 42 sizes are provided. In one aspect, the length of the spacer 42 is varied to accommodate different fill volumes within the container 14. Alternatively, a single size of spacer 42 may be utilized, and multiple fill volumes within the container 14 may be accommodated by utilizing multiple shims received by the spacer 42.

[0022] Referring to FIGS. 17 to 26, the drive assembly 12 includes a first plunger member 52, a second plunger member 54 received by the first plunger member 52, a first biasing member 56, a second biasing member 58, a plunger actuating member 60, and an index member 62. The first plunger member 52 is movable from a pre-use position (shown in FIG. 18) to a use position (shown in FIG. 19) and a post-use position (shown in FIG. 20), and the first plunger member 52 is configured to engage the spacer assembly 40 and move the stopper 34 into the container 14 to dispense the drug from the container 14. The first plunger member 52 is configured to move axially. The second plunger member 54 and the first plunger member 52 form a nested structure, and the second plunger 54 is configured to move axially after the first plunger member 52 has moved a predetermined axial distance. The movement of the first and second plunger members 52, 54 is provided by the first and second biasing members 56, 58 which are compression springs, although other suitable configurations for the biasing members 56, 58 may be utilized.

[0023] The first biasing member 56 is received within the second plunger member 54 and constrained between the plunger actuating member 60 (and index member 62) and the first spring seat 64 of the second plunger member 54. The second biasing member 58 is disposed radially inwardly of the first biasing member 56 and is received by the second plunger member 54. The second biasing member 58 is constrained between the second spring seat 66 of the second plunger member 54 and the first plunger member 52. The second biasing member 58 is configured to bias the first plunger member 52 from a pre-use position to a use position and a post-use position toward the container. The first biasing member 56 is configured to bias the second plunger member 54 toward the container 14, and the second plunger member 54, in turn, biases the first plunger member 52 from a pre-use position to a use position and a post-use position toward the container 14. More specifically, the second biasing member 58 is configured to drive the first plunger member 52 toward the spacer assembly 40 or the stopper 34, move the container 14 to engage the valve assembly 16, thereby piercing the closure 36 of the container 14 and placing the container 14 in fluid communication with the needle 28. The first biasing member 56 is configured to move the stopper 34 within the container 14 and dispense the medicament into the container 14. The second biasing member 58 has a spring constant different from that of the first biasing member 56. In particular, the second biasing member 58 is stiffer than the first biasing member 56 and provides a high force for piercing the closure 36 of the container 14, while the first biasing member 56 provides a force for proper dispensing relative to the viscosity of the fluid or medicament within the container 14.

[0024] Referring again to FIGS. 17 - 26, the plunger actuating member 60 has an annular portion 68 and a spindle portion 70. The plunger actuating member 60 is movable in a rotational direction relative to the first plunger member 52 between a first rotational position and a second rotational position spaced from the first rotational position. The first rotational position can be 15 degrees from the second rotational position, although other suitable positions can be utilized. The annular portion 68 includes a drive surface 72 that includes a plurality of gears 74, although other suitable arrangements can be utilized as the drive surface 72. The spindle portion 70 includes an actuator lock surface 76 configured to engage and disengage from the plunger lock surface 78 of the first plunger member 52. The plunger lock surface 78 includes a plurality of protrusions 80 configured to be received by a plurality of slots or notches 81 defined by the actuator lock surface 76.

[0025] As shown in FIGS. 18 and 23, at the first rotational position of the plunger actuating member 60, the plurality of protrusions 80 and the plurality of slots or notches 81 are not aligned, and the plunger actuating member 60 engages with the first plunger member 52 to prevent movement of the first and second plunger members 52, 54, and the first and second biasing members 56, 58 bias the first and second plunger members 52, 54 away from the plunger actuating member 60. As shown in FIGS. 19 and 24, at the second rotational position of the plunger actuating member 60, the plurality of protrusions 80 and the plurality of slots or notches 81 are aligned with each other, the plunger actuating member 60 is disengaged from engagement with the first plunger member 52, enabling movement of the first and second plunger members 52, 54, thereby initiating the dispensing process from the container 14.

[0026] Referring to FIGS. 7 and 33, the drive surface 72 of the plunger actuating member 60 is configured to be engaged by a part of the needle actuator assembly 18. Although details will be described later, after the engagement of the actuator button 26 and the release of the needle actuator assembly 18, the needle actuator assembly 18 moves within the housing 20 from the pre-use position to the use position and the post-use position. During the initial movement of the needle actuator assembly 18, a part of the needle actuator assembly 18 engages with the drive surface 72 of the plunger actuating member 60 to move the plunger actuating member 60 from the first rotational position to the second rotational position. As shown in FIG. 33, the inclined blade portion 82 of the needle actuator assembly 18 engages with the drive surface 72 of the plunger actuating member 60 to effect rotation of the plunger actuating member 60.

[0027] Referring to FIGS. 11, 13, and 26, the second plunger member 54 includes a plurality of encoding protrusions 84, and a preselected one of the plurality of encoding protrusions 84 is configured to engage a regulatory member 86 of the system 10. As will be described in more detail below, the regulatory member 86 cooperates with the needle actuator assembly 18 to limit movement of the needle actuator assembly 18 from its use position to its post-use position until a predetermined administration end position of the stopper 34 is reached. In one aspect, the regulatory member 86 is configured to limit axial movement of the needle actuator assembly 18 from the use position via engagement between the regulatory member 86 and a portion of the needle actuator assembly 18. Such engagement between the regulatory member 86 and the needle actuator assembly 18 is released by rotation of the regulatory member 86 when the stopper 34 reaches the administration end position. During the use position of the needle actuator assembly 18, the regulatory member 86 is biased in a rotational direction, and rotation of the regulatory member 86 is prevented via engagement between the regulatory member 86 and one of the plurality of encoding protrusions 84 of the second plunger member 54. The plurality of encoding protrusions 84 can be axial ribs of varying lengths, although other suitable arrangements can be utilized. Each of the encoding protrusions 84 defines a point at which the regulatory member 86 can rotate to release the needle actuator assembly 18. The smooth portion of the second plunger member 54 can provide an additional "code" for determining when the system 10 transitions to the administration end position.

[0028] As described above, the indicator arrangement 32 moves as the system 10 moves from its pre-use, in-use, and post-use or administration end positions, and different portions of the indicator arrangement 32 are visible through the indicator window 30. More specifically, the indicator arrangement 32 engages a portion of the regulatory member 86 and moves with the regulatory member 86 through the various stages of the system 10 to provide an indication to the user regarding the state of the system 10.

[0029] During the assembly of system 10, the dosage of container 14 is adapted to a specific spacer 42 having a set length, and a corresponding one of the plurality of encoding protrusions 84 is aligned with the regulating member 86. Thus, as described above, container 14 can provide a plurality of dosages, each volume corresponding to a specific spacer 42 and encoding protrusion 84. Thus, even for different dosages, system 10 is configured to inject needle 28 into the user to deliver a dosage of the medicament from container 14, retract injection needle 28 after the dosage has been administered, and provide an indication of the state of system 10, while minimizing a sudden engagement of stopper 34 by drive assembly 12. In particular, the size of stopper 34 can be selected to minimize the distance between the first plunger member 52 and the spacer assembly 40, obviating the need for the use of damping materials.

[0030] Referring to FIGS. 27-33, a drive assembly 12A according to a further aspect of the present invention is shown. The drive assembly 12 shown in FIGS. 27-33 is similar to and operates in the same manner as the drive assembly 12 shown and described above in FIGS. 17-26. In the drive assembly of FIGS. 17-26, however, the first plunger member 52 is received within the second plunger member 54 and extends from the second plunger member 54 during axial movement from the pre-use position to the use position. Further, the first plunger member 52 includes an extension portion 88 configured to engage the second plunger member 54 after the first plunger member 52 has moved a predetermined axial distance, and the first plunger member 52 and the second plunger member 54 move together. The first and second biasing members 56, 58 engage and act on the first and second plunger members 52, 54 in the same manner as the drive assembly 12 of FIGS. 17-26.

[0031] Referring to FIGS. 27-32, index member 62 is disposed around first and second plunger members 52, 54 and includes a plurality of ratchet teeth 90 configured to engage a flexible tab 92 disposed at the bottom 24 of housing 20. When drive assemblies 12, 12A are attached to the bottom 24 of housing 20, engagement of the ratchet teeth 90 of index member 62 with the flexible tab 92 of housing 20 provides one-way rotation of index member 62. Index member 62 is configured to rotate to align one of the coding protrusions 84 of second plunger member 52 with a regulating member 86 based on the dosage and the size of spacer 42 described above. Index member 62 may provide drive assemblies 12, 12A having 24 rotational positions that may have unique dosage values associated therewith.

[0032] Referring to FIGS. 1-16 and FIGS. 34-40B, a needle actuator assembly 18 according to one aspect of the present invention is shown. Needle actuator assembly 18 includes a needle actuator body 96 having a guide surface 98, a needle shuttle 102 having a cam surface 104, and a needle 28 received by needle shuttle 102 and configured to be in fluid communication with container 14 as described above. Needle actuator body 96 is generally rectangular and guide surface 98 projects radially inward. Needle shuttle 102 is received within needle actuator body 96. As described above, needle actuator body 96 is movable within housing 20 from a pre-use position (shown in FIGS. 4-6), an initial actuation position (FIGS. 7-9), a use position (FIGS. 10-12), and a post-use position (FIGS. 13-15). Needle actuator body 96 is biased from the pre-use position to the post-use position via an extension spring 106, although other suitable biasing arrangements may be utilized. Needle actuator body 96 is released by engagement of actuator button 26 and is free to move from the pre-use position to the use position, which will be described in detail later. Needle actuator body 96 moves from the use position to the post-use position after rotation of regulating member 86 as described above with reference to FIGS. 17-33.

[0033] Referring to FIGS. 34 to 40B, the needle shuttle 102 is movable along a vertical axis between a retracted position where the needle 28 is disposed within the housing 20 and an extended position where at least a portion of the needle 28 extends outside the housing 20. The needle shuttle 102 is configured to move between the retracted position and the extended position by engagement of a guide surface 98 of the needle actuator body 96 and a cam surface 104 of the needle shuttle 102. The cam surface 104 is provided by first and second cam members 108, 110, and the first cam member 108 is spaced apart from the second cam member 110. The housing 20 includes a guide post 112 having a recess configured to receive a T-shaped projection 114 on the needle shuttle 102, although other shapes and configurations may be utilized for the guide post 112 and the T-shaped projection 114. The needle shuttle 102 moves along the guide post 112 between the retracted position and the extended position. The guide post 112 is linear and extends substantially perpendicular to the housing 20, although other suitable arrangements may be utilized. The guide surface 98 of the needle actuator body 96 is non-linear and includes a first side surface 116 and a second side surface 118 located on the side opposite the first side surface 116, respectively.

[0034] As described below, the guide surface 98 of the needle actuator body 96 cooperates with the cam members 108, 110 of the needle shuttle 102 such that when the needle actuator body 96 moves axially from its pre-use position to its post-use position, the needle shuttle 102 is vertically moved between a retracted position and an extended position. The needle shuttle 102 also includes a shuttle biasing member 120 configured to engage the housing 20 or the actuator button 26. In particular, the shuttle biasing member 120 engages the housing 20 or the actuator button 26 and provides a biasing force when the needle actuator body 96 is transitioning from its use position to its post-use position. When the needle actuator body 96 has fully transitioned to its post-use position, the cam members 108, 110 of the needle shuttle 102 disengage from the guide surface 98 of the needle actuator body 96 and the shuttle biasing member 120 biases the needle shuttle 102 downward such that, as described above, the needle 28 engages the pad 38. However, as described above with respect to FIGS. 1-16, the pad 38 may be biased by the needle 28 rather than biasing the needle shuttle 102 downward via the shuttle biasing member 120. The needle actuator body 96 may interact with the actuator button 26 to prevent the actuator button 26 from snapping back until the post-use position is reached, which will be described in more detail below.

[0035] Referring to FIGS. 37A - 40B, in the pre - use position (FIG. 37A), the needle shuttle 102 is in the retracted position, and the cam members 108, 110 are spaced from the guide surface 98 of the needle actuator body 96. When the needle actuator body 96 moves to the use position (FIGS. 37B and 38A), the second cam member 110 of the needle shuttle 102 engages with the second side surface 118 of the guide surface 98, moving the needle shuttle 102 from the retracted position to the extended position. During the transition of the needle actuator body 96 from the use position to the post - use position (FIG. 37C), the first cam member 108 of the needle shuttle 102 engages with the first side surface 116 of the guide surface 98, moving the needle shuttle 102 from the second position to the first position. After the needle actuator body 96 has been fully transitioned to the post - use position (FIGS. 37D and 38B), the shuttle biasing member 120 biases the needle shuttle 102 downward when the cam members 108, 110 disengage from the needle guide surface 98, and the needle 28 engages with the pad 38. The transition of the needle actuator body 96 and the corresponding positions of the needle shuttle 102 are also shown in FIGS. 39 - 40B. The interaction between the actuator button 26 and the needle actuator body 96 is described in detail in connection with FIGS. 65A - 67. Referring to FIGS. 41 - 64, a drug delivery system 200 according to a further embodiment is shown. The system 200 includes a housing 202 having an upper housing 204 and a lower housing 206. The housing has a proximal end 205 and a distal end 207. The upper housing 204 has a status viewing port 208 through which a user can view the operating status of the system 200. The system 200 also includes a valve assembly 212 and a tube 214 fluidly connecting the valve assembly 212 to a patient needle 215 disposed at the proximal end of a needle arm 216. A spring 218 biases the needle actuator 220 in the distal direction.

[0036] As shown in FIGS. 42 - 46, the system 200 further includes a container or drug container 222 in which a stopper 224 is movably disposed, although the stopper 224 is omitted from various figures for clarity. Preferably, the distal end of the drug container 222 has a septum assembly 228 spaced from the valve assembly 212 prior to operation of the device, as best shown in FIG. 47.

[0037] For manufacturing purposes, it is often desirable to use one size as the drug container even when multiple fill volumes or dosages may be used with the container. In such cases, when the drug container is filled, different fill volumes result in different positions of the stopper. To accommodate such different stopper positions and manufacturing differences of the stopper, aspects of the present invention include a custom or off-the-shelf spacer 226 disposed at the proximal end of the container 222 proximate to the stopper 224. In other words, the custom spacer 226 provides an option that allows the manufacturer to distribute within a predetermined fill volume range set by selecting different spacers 226, reducing or eliminating the need for assembly configuration operations. The size of the spacer 226 can be adopted to provide a bearing surface that coincides with the proximal end of the container in consideration of the underfill of the container 222.

[0038] The spacer 226 is selected from a plurality of spacers 226 of different sizes and occupies the space from the proximal end of the stopper 224 to the proximal end of the container 222. According to one embodiment, as shown in FIGS. 45 - 47, the spacer 226 is selected to be substantially in the same plane as the proximal end of the container 222. Further, according to one embodiment, the spacer 226 has a "silk hat" shape including a central column 230 and a distal flange 232, as best shown in FIG. 45.

[0039] Returning to FIGS. 44 - 47, the system 200 also includes a drive assembly 234 for establishing a fluid connection between the container 222 and the patient needle 215 and displacing the container 222 distally to discharge the drug from the container 222. More specifically, the drive assembly 234 includes an inner spring 236 disposed within a central plunger 238, an outer plunger 240, an outer spring 242 disposed between the central plunger 238 and the outer plunger 240, a nested member 244, and a release gate 246.

[0040] Preferably, the inner spring 236 has a spring constant greater than that of the outer spring 242 and is thus stronger or more rigid than the outer spring 242. The inner spring 236 is disposed inside the central plunger 238 and presses between the spring flange 248 of the lower housing (best shown in FIG. 46) and the central plunger 238, and the central plunger 238 directly presses the proximal end of the spacer 226 after the operation of the device. The outer spring 242 is disposed inside the outer plunger 240 and presses between the proximal outer flange 250 of the central plunger 238 and the distal inner flange 252 of the outer plunger 240. Thus, the inner spring 236 and the outer spring 242 are nested and can provide a more compact drive assembly (and thus a more compact system 200) than using a single spring.

[0041] According to one aspect, the inner spring 236 acts only to displace the container 222 to establish fluid connection with the patient needle 215, and the outer spring 242 acts only to subsequently administer the drug from the container 222. According to another aspect, the inner spring 236 acts to displace the container 222 to establish fluid connection with the patient needle 215 and also acts to begin dispensing the drug from the container 222, and the outer spring 242 acts to complete the administration of the drug. In a further aspect, the inner spring 236 causes the initial piercing of the container 222, and the outer spring 242 completes the piercing and the dispensing of the drug from the container 222.

[0042] As shown in FIGS. 44-47 and as will be described further in detail below, the outer plunger 240 includes a pair of proximal flanges or feet 254, each having an inclined surface that interacts with a corresponding inclined surface (or surfaces) of the release gate, and holds and subsequently releases the power module after the device 200 is actuated.

[0043] As best shown in FIGS. 46 and 47, when initially assembled, the container 222 is positioned with a gap from the drive assembly 234 and the valve assembly 212. The side flange 256 of the needle actuator 220 axially holds the drug container 222, and the needle actuator 220 prevents the release gate 246 from being displaced laterally. According to one embodiment, a spring (not shown) biases the needle actuator 220 distally, but the activation button 210 (and / or its associated assembly) prevents the distal displacement of the needle actuator 220 before the device 200 is activated. The status bar 258 is disposed on the needle actuator 220 and has an upper surface visible through the status viewing port 208. According to one embodiment, the upper surface of the status bar has a plurality of colors or patterns, and when the device is in the pre-activated state, a first color or pattern such as yellow is visible through the status viewing port 208.

[0044] Also, FIGS. 48 - 52 are top views of the system 200, showing the operation of events during and after the operation of the system 200. In FIG. 47, the user slides the activation button 210 proximally and then displaces the button 210 vertically into the housing 202, thereby releasing the needle actuator 220 to be displaced distally under the influence of a spring (omitted for clarity). As shown in FIG. 49, when the needle actuator is displaced distally, the track 260 of the needle actuator 220 interacts with the lateral boss 262 of the needle arm 216 to insert the patient needle 215. Preferably, at this stage, the proximal end of the needle actuator 220 has not yet passed through the release gate 246, and thus the drive assembly 234 is not yet released. However, the side flange 256 is displaced distally, and thus the container 222 is not constrained.

[0045] Subsequently, as shown in FIGS. 50 and 51, with continued distal movement, the proximal end of the needle actuator 220 passes through the release gate 246 (thereby releasing the drive assembly 234). The needle actuator 220 temporarily bears against a feature on the rotatable release flipper 264 and presses the release flipper 264 against the outrigger 266 of the nested member 244 (best shown in FIGS. 44 and 59). The needle actuator 220 remains in this position until the drug is dispensed. In this position, preferably, a second color or pattern of the status bar 258, such as green, is visible through the status viewing port 208.

[0046] At this stage, due to the forces of springs 236 and 242 and the interaction between the inclined surface of the proximal flange or foot 254 and the corresponding inclined surface (or surfaces) of the release gate 246, the release gate 246 is displaced laterally, thereby releasing the outer plunger 240 from its restraining interaction with the release gate 246. Until this point, the outer plunger 240 has been restraining the central plunger 238.

[0047] Referring to FIGS. 52 and 53 (for clarity, the inner spring 236 is omitted from FIG. 52), the stiff inner spring 236 drives the central plunger 238 distally into contact with the spacer 226. Since the drug container 222 is filled with a substantially non-compressible fluid, the continued distal displacement of the central plunger 238 displaces the spacer 226, the stopper 224, and the container 222 distally relative to the housing 202. This distal displacement results in the septum assembly 228 being pierced by the valve assembly 212, establishing fluid communication between the container 222 and the patient needle 215. The central plunger 238 moves distally until its proximal outer flange 250 (best shown in FIG. 59) contacts the flange of the lower housing 206, thereby limiting the "puncture movement". Preferably, another flange on the lower housing 206 and / or the lateral flange 256 of the needle actuator 220 limits the distal movement of the container 222.

[0048] Subsequently, since the inner spring 236 can no longer displace the central plunger 238 distally, the weaker outer spring 242 displaces the outer plunger 240 distally relative to the central plunger 238 so as to contact the distal flange 232 of the spacer 226, as shown in FIGS. 54 and 55. As will be explained in more detail later, preferably, the contact between the outer plunger 240 and the spacer 226 is damped to minimize the impact force. Further expansion of the outer spring 242 displaces the outer plunger 240 distally to dispense the drug.

[0049] As shown in FIGS. 56 and 57, when the outer spring 242 continues to expand and displace the outer plunger 240 distally, with a predetermined distal displacement of the outer plunger 240 with respect to the nested member 244 thereof, the outer structure or flange 268 of the outer plunger 240 interacts with the inner distal structure or flange 270 of the nested member 244 in order to "pick up" the nested member 244. This ensures further distal displacement of the outer plunger 240 and results in corresponding distal displacement of the nested member 244. This pair of distal displacements continues until the end of drug administration.

[0050] As described above, the outrigger 266 is disposed on the nested member 244. The axial length of the outrigger and the distal movement of the nested member 244 control the timing of the disengagement between the outrigger 266 and the release flipper 264. As shown in FIGS. 58 and 59, at the end of drug dispensing, the proximal end of the outrigger 266 bypasses the release flipper 264. This allows the release flipper 264 to disengage from the engagement with the needle actuator 220 (FIG. 60) and rotate, enabling the needle actuator 220 to continue its distal displacement and retract the patient needle 215 (FIG. 61). At this stage, through the status viewing port 208, another color or pattern of the status bar 258, for example red, is visible, indicating that the device 200 has completed its operation.

[0051] As described above, the contact between the outer plunger 240 and the spacer 226 is preferably attenuated in order to minimize the impact force, as shown in FIGS. 62 and 63. For an underfilled syringe containing a viscous fluid, the outer spring 242 becomes stiffer to provide the desired dispensing rate, so the highest level of energy dissipation is desirable. For a fully filled syringe containing a low-viscosity fluid, the outer spring can be less rigid to provide the desired dispensing rate, so the lowest level of energy dissipation is desirable. Various methods, such as air attenuation or discrete bubble attenuation, are employed to adjust the attenuation level.

[0052] As another method of attenuating the impact force, FIG. 64 shows an embodiment of the spacer 226 in which one or more axial boundary ribs 272 are circumferentially arranged around the central column 230 of the spacer 226. In this embodiment, the outer plunger 240 must travel beyond the interference rib 272, which provides frictional resistance to the distal displacement of the outer plunger 240 relative to the spacer 226. The frictional force generated by the interference between the interference rib 272 and the outer plunger 240 is independent of the plunger velocity. Preferably, the frictional force does not exceed the minimum dispensing spring load in order to avoid stalling a weak spring. The interference can be adjusted to provide a desired level of frictional resistance. For different fluid viscosities, different dimensions (axial and / or radial) of the interference rib 272 can exist. This means that there can be multiple aligned positions corresponding to each combination of viscosity and fill level, or to the number of springs required within a viscosity range, such that a particular position can be set for a particular reference dimension spring (that position having an adjusted interference / attenuation for that particular spring load / viscosity scenario).

[0053] Referring to FIGS. 65A - 69, an actuator button device 280 for operating a system 10 according to one aspect of the present invention is shown. The actuator button device 280 includes an actuator button 26, a button spring 284, and a needle actuator body 286. The needle actuator body 286 may be similar to the above-described needle actuator bodies 96, 220 and is configured to move within the housing 20 to shift the needle shuttle 102 or the needle 28 between a retracted position and an extended position. As shown in FIG. 69, the actuator button 26 includes a user interface portion 288 for interfacing with a user. Preferably, the user interface portion 288 has a length of about 22 mm and a width of about 10 mm, although other suitable dimensions may be utilized. The actuator button 26 includes two pairs of lockout arms 290, 292 that interact with the button contact surfaces 294, 296 of the needle actuator body 286 to prevent the needle actuator body 286 from rocking upward before device activation. As shown in FIG. 65H, the overlap between the needle actuator body 286 and the housing 20 prevents premature actuation. Referring to FIG. 66, the button spring 284 includes a first support surface 298, a second support surface 300 spaced from the first support surface 298, and a cantilevered central spring arm 302 surrounded by a pair of outer arms 304 connected by the first support surface 298.

[0054] The actuating button device 280 is configured to provide one or more of the following features, which will be discussed in more detail below. Axial displacement or sliding of the actuator button 26 in one direction, lateral movement (rise and fall positions) of the actuator button 26 when the actuator button 26 remains depressed between the use positions of the needle actuator body 286, and lockout of the actuator button 26 at the post-use position of the needle actuator body 286 such that the button 26 is in the raised position and cannot be depressed by the user.

[0055] To operate the system 10 using the actuator button 26, the user first slides the user interface portion 288 in a first axial direction such that it is on the right side as shown in FIGS. 65G and 65H. The user may need to slide the user interface portion 288 about 10 mm or about 8 mm, although other suitable distances may be utilized. The movement of the actuator button 26 axially moves the lockout arms 290, 292, passes through the button contact surfaces 294, 296 of the needle actuator body 286, and enables movement of the actuator button 26 from its raised position to its lowered position.

[0056] When the user slides the user interface portion 288 distally, the central spring arm 302 of the button spring 284 rides over the spring receiving surface 306 of the housing 20, and the first and second bearing surfaces 298, 300 engage the first and second support inclined surfaces 308, 310 of the housing 20. The force of the button spring 284 is balanced by engagement with the spring arm bearing surface 306 and the first and second support inclined surfaces 308, 310, providing smooth axial displacement or sliding of the actuator button 26.

[0057] When the actuator button 26 and the button spring 284 reach the end of their axial sliding movement, the central spring arm 302 and the first bearing surface 298 pass the ends of their respective stoppers 312, 314, preventing the actuator button 26 from returning to its original position as shown in FIG. 65H. Further, when the actuator button 26 and the button spring 284 reach the end of their axial sliding movement, the user engages the user interface portion 288 to move the actuator button 26 to its lower, lowered position. The actuator button 26 is depressed about 2 mm, and the minimum force required to depress the actuator button 26 is about 3 N, most preferably about 2.8 N, although other suitable distances and minimum forces may be utilized.

[0058] When the user presses the user interface portion 288 shown in FIGS. 65A and 65B, the actuator button 26 rotates the needle actuator body 286 and releases the needle actuator body 286, thereby causing the needle actuator body 286 to move from the pre-use position to the use position. As shown in FIG. 65B, when the needle actuator body 286 moves to the use position, the lockout arms 290, 292 travel along the lower surfaces of the button contact surfaces 294, 296, preventing the actuator button 26 from bouncing upward. After the drug has been delivered, when the needle actuator body 286 moves from the use position to the post-use position, as shown in FIG. 65C, the lockout arms 290, 292 disengage from the button contact surfaces 294, 296, allowing the actuator button 26 to bounce back under the influence of the button spring 284. When the needle actuator body 286 has completely moved to the post-use position shown in FIG. 65D, the actuator button 26 has completed its movement from the lowered position to the raised position by the biasing force of the button spring 284. When the needle actuator body 286 is in the post-use position, the spring arm 316 on the needle actuator body 286 engages the actuator button 26 to prevent the actuator button 26 from moving to the lowered position, although axial movement is still restricted by engagement with the stoppers 312, 314 of the spring arm 302. Thus, the actuator button 26 is locked after drug delivery is complete, providing a clear indication between a used and an unused system.

[0059] Furthermore, if the user holds down the actuator button 26 during drug administration, appropriate dosing and needle retraction still complete, but the actuator button 26 does not return to the raised position until the button 26 is released.

[0060] In one aspect, the button spring 284 is made of plastic. The button spring 284 could also be a pressed metal spring instead, although any other suitable material could be utilized.

[0061] 68-68G, rather than providing a separate actuator button 26 and button spring 284, the spring may be integral with the button 26. More specifically, an actuator button 320 according to a further embodiment of the present invention includes an integral spring arm 322. The actuator button 320 also includes a lockout arm 324, a retention arm 326, and a rear pivot 328. As shown in FIGS. 68D and 68E, the spring arm 322 engages a protrusion 330 on the top 22 of the housing 20. During transition of the system 10 from the pre-use position to the use position, the spring arm 322 slides past a detent on the protrusion 330, which provides an axial spring force. An end of the spring arm 322 engages a portion of the top 22 of the housing 20, providing a vertical spring force as the spring arm 322 deflects. The actuator button 320 is configured for a fluid movement between sliding and depressing the button 320, even though two separate movements occur, similar to the operation of button 26 described above. During the transition between the pre-use and use positions, the button 320 pivots about pivot 328 and the retaining arm 326 engages a portion of the needle actuator body 286, thereby maintaining the button 320 in a depressed position until the end-of-dose position is reached, in a manner similar to actuator button 26. Once the needle actuator body 286 moves to the end-of-dose position, the lockout arm 324 flexes inward and engages a portion of the needle actuator body 286, thereby preventing further movement of the actuator button 320, in a manner similar to actuator button 26 described above.

[0062] Aspects of the present invention provide improvements over previous button designs. For example, the activation button device 280 provides multiple surfaces that hold the needle actuator body 286 in place against the needle actuator spring 106 prior to activation, thereby reducing the likelihood of premature activation during a drop impact. The activation button device 280 physically prevents the needle actuator body 286 from moving prior to activation by holding the needle actuator body 286 in a tilted (locked) position so that the surfaces do not allow room for pre-activation.

[0063] In addition, the button sliding force of the actuation button device 280 is more precisely controlled by using a bending arm rather than a simple bump detent. This enables a longer sliding stroke of the button 26 with better force control, resulting in a more economical and effective design. Further, the actuation button device 280 causes the button 26 to be pushed back at the end of the injection, providing the user with additional visual, auditory, and tactile indications that the drug delivery is complete.

[0064] According to one aspect, the fluid delivery volume of the system 10 is determined by the end position of the plunger relative to a point within the housing, regardless of the actual fill volume, the inner diameter of the container, and the starting position and length of the stopper. Since the tolerances of the above factors can be very large, the variation in dosing accuracy can have significant implications. Aspects of the present invention enable the elimination of some or all of these tolerances from dosing issues, resulting in a more accurate and less variable drug injection volume.

[0065] Referring to FIGS. 70A - 70G, a spacer assembly 400 for use in connection with a drive assembly according to one aspect of the present invention is shown.

[0066] The elements within the chain of tolerances of the stopper spacer assembly 400 include the thickness (A) of the flange 402 of the inner plunger 404, the internal length (B) of the outer plunger 406 between the inner proximal end 408 and the inner shoulder 410, and the initial offset distance (C1) between the inner plunger flange 402 and the inner proximal end 408 of the outer plunger. This initial offset distance (C1) is preferably greater than the gap distance (C2) between the outer plunger 406 and the proximal end of the drug barrel 412. The chain of tolerances of the stopper spacer assembly 400 also includes the internal barrel diameter (D). Once assembled, the stopper spacer 414 and the outer plunger 406 are specific for a given drug amount.

[0067] Figures 70B to 70G show the operation of the stopper spacer assembly 400. As shown in Figure 70B, when the system is activated, both the inner plunger 404 and the outer plunger 406 are released. The outer spring 416 pushes the outer plunger 406 into the barrel 412, compresses the damping material 418, and pushes the inner spring 420. The stopper 422 has not yet moved relative to the barrel 412 for the fluid column of the drug.

[0068] Next, as shown in Figure 70C, the outer spring 416 displaces the outer plunger 406 and the barrel 412 distally, opening a valve (not shown) at the distal end of the barrel 412 and establishing fluid communication with a needle (not shown). Due to the incompressibility of the liquid drug, the stopper 422 cannot be displaced relative to the barrel 412 until the valve is opened and a fluid path to the patient needle is established.

[0069] Subsequently, as shown in Figures 70D and 70E, the inner spring 420 displaces the inner plunger 404, the stopper spacer 414, and the stopper 422 to dispense the fluid.

[0070] Figure 70F shows the end of drug delivery when the proximal flange 402 of the inner plunger 404 contacts the inner shoulder 410 of the outer plunger 406, thereby stopping the displacement of the inner plunger 404 (and the stopper spacer 414 and the stopper 422) relative to the drug barrel 412 and stopping the flow of the drug.

[0071] According to one aspect, as shown in Figure 70G, the stopping of the displacement of the inner plunger 404 relative to the drug barrel 412 triggers an end-of-dose indicator for the system.

[0072] Referring to FIGS. 71 and 72, the folding spacer assembly 430 includes a front spacer portion 432 fixed to a stopper 434, an inner plunger 436, a rear spacer portion 438, and a rotating shuttle 440. The inner plunger 436 can be repositioned relative to the front spacer portion 432 but does not rotate relative to the front spacer portion 432. Similarly, the rear spacer portion 438 can move axially relative to the front spacer portion 432 but does not rotate relative to the front spacer portion 432. As will be described in detail later, the rotating shuttle 440 first rotates and then changes position.

[0073] According to one aspect, the front spacer portion 432 is firmly fixed to the stopper 434. Those skilled in the art will understand that many methods can be employed to fix the front spacer portion 432 to the stopper 434, such as, for example, adhesives, mechanical fasteners, or any other suitable arrangement. Preferably, the front spacer portion 432 includes threads that engage mating threads within the stopper 434.

[0074] When the stopper spacer assembly 430 is screwed into the stopper 434, an axial load is applied through the access opening 442 of the rear spacer portion 438. This force can be used to push the stopper 434 forward and apply pressure to the fluid agent. This pressure causes the front (distal) face of the stopper 434 to deflect and press proximally, pushing the rear spacer portion 438 back and rotating the rotating shuttle into an "assembled" state. In other words, when the drug barrel is filled with drug and the plunger of the system applies an axial force to the drug through the spacer assembly 430, the distal face of the stopper 434 deforms due to the pressure of the drug. During drug delivery, pressure is applied to the rear spacer portion 438 by the drive assembly (through the plunger), applying a rotational torque to the rotating shuttle 440 through the helical surface 444 of the rear spacer portion 438. However, the deformation of the stopper from the drug applies a rearward or proximal force to the inner plunger 436, preventing the rotation of the rotating shuttle 440.

[0075] According to one aspect, by increasing the length of the inner plunger 436, the axial reaction load on the inner plunger 436 can be increased.

[0076] When drug delivery is complete, as shown in FIG. 73, the pressure of the stopper 434 decreases, thereby enabling the distal end of the inner plunger 436 to be displaced distally. This distal displacement enables the rotary shuttle 440 to rotate. The subsequent axial force applied by the drive assembly rotates and displaces the rotary shuttle 440 distally by the interaction between the helical surface 444 of the rear spacer portion 438 and the corresponding cam surface arm 446 of the rotary shuttle 440. According to one aspect, this final movement of the rotary shuttle 440 causes the drive assembly to trigger the retraction of the needle.

[0077] Referring to FIGS. 74 and 75, a restraint member 452 according to one aspect of the present invention is arranged with the drive assembly. The restraint member 452 manages the timing of the final displacement of the needle actuator bodies 96, 220 after completion of the drug dosage. Instead of rotating around the fixed post, the restraint member 452 floats freely. When the plunger is displaced sufficiently distally (as shown in FIGS. 74 and 75) and the gap aligns with the restraint member 452, the restraint member 452 is displaced laterally into the gap due to the spring force on the needle actuator bodies 96, 220 and the inclined surface 454 at the rear of the arm of the restraint member 452 that engages the needle actuator body (best shown in FIG. 75). When the restraint member no longer holds the needle actuator bodies 96, 220, the needle actuator bodies 96, 220 are free to complete their axial movement to the post-use position. Also, as shown in FIG. 75, the restraint member 452 is biased against the rear of the barrel of the container 14, which minimizes the accumulation of tolerances of the various components and improves dosing accuracy.

[0078] Referring to FIGS. 76-78, a spacer assembly 460 according to a further aspect of the present invention is shown. The spacer assembly 460 shown in FIGS. 76-78 allows for the removal of the results of manufacturing tolerance accumulation through adjustment of the spacer assembly, thereby allowing each system to inject the same amount of drug.

[0079] As shown in FIG. 77, the spacer assembly 460 includes a stopper 462 and a stopper spacer 464. The stopper spacer 464 includes a fixed spacer piece or fixed spacer 466 fixedly connected to the stopper 462, and an adjustable spacer piece or adjustable spacer 468 rotatably displaceable in one direction relative to the fixed spacer 466.

[0080] One of ordinary skill in the art will understand that many methods, such as adhesives, mechanical fasteners, or other suitable arrangements, may be used to fix the fixed spacer 466 to the stopper 462. Preferably, the fixed spacer 466 includes one or more outer threads that engage one or more mating threads within the stopper 462. According to one aspect, the adjustable spacer 468 has a distal stem with an outer thread 470. The distal stem thread 470 engages an inner thread 472 within the fixed spacer 466 (best shown in FIG. 78) and controls the axial displacement of the adjustable spacer 468 relative to the fixed spacer 466 by rotation.

[0081] As shown in FIGS. 76 and 77, the fixed spacer 466 includes radially spaced detents 474, and the adjustable spacer 468 includes a spring-loaded detent arm 476 whose free end engages one of the selected detents 474, preventing rotation and axial displacement of the adjustable spacer 468 toward the fixed spacer 466. The free end of the spring-loaded detent arm 476 is shaped to pass over the detent 474 in one direction, thereby allowing the adjustable spacer 468 to rotate and axially displace proximally away from the fixed spacer 466.

[0082] Despite changes in the dimensions of the stopper and the container, the adjustable spacer 468 can be adjusted relative to the fixed spacer 466, providing a constant axial length of the spacer assembly 460.

[0083] As shown in FIG. 78, once the container is filled, an axial load, such as the load that would be encountered when attached to the systems 10, 200, is applied to the adjustable spacer 468 (and thus the fixed spacer 466 and the stopper 462). When the axial load is applied, the adjustable spacer 468 can retreat proximally, ensuring a constant gap 478 between the proximal end of the drug barrel 480 and the proximal surface of the adjustable spacer 468, thereby rendering inoperable variations within the drug barrel glass and the compressibility of any trapped air. In other words, the spacer assembly 460 allows the adjustable spacer 468 to have a predetermined set position relative to the container 14, independent of variations in the container 14 and the length of the stopper. Thus, the starting position of the spacer assembly 460 is a predetermined distance from the container 14, the end position of the spacer assembly 460 is also a predetermined distance from the container 14, and the movement of the stopper 462 is defined by the effective lengths of the plungers 52, 54 of the drive assembly 12.

[0084] Referring to FIGS. 79 and 80, the base column 482 and the cap 484 of the automatic adjustment spacer 486 according to one aspect of the present invention are shown. The base column 482 includes a base portion 488 and an axially extending column 490. According to one embodiment, the base column 482 includes a plurality of columnar protrusions 491, and each of the columnar protrusions 491 has a plurality of ratchet teeth 492 disposed at its proximal portion. The locking barb 493 is disposed at the proximal end of each of the plurality of ratchet teeth 492. The cap 484 is hollow, and the distal end of the cap 484 includes one or more axial springs 494. According to one aspect, the axial spring 494 is bent and is a cantilever arm formed during the molding of the cap 484. According to another aspect, a separate biasing member such as a compression spring may be employed in the automatic adjustment spacer 486. When assembled with the base column 482, the spring 494 engages the base portion 488 and maintains an initial spacing between the base column 482 and the cap 484. According to one aspect, the spring 494 is omitted. The cap 484 also includes a plurality of flexible cantilever arms or tabs 496, each of which has a free proximal portion having a plurality of ratchet teeth 497. The proximal end of each flexible tab 496 includes a leg 498.

[0085] FIG. 81B shows the cap of the automatic adjustment spacer deployed within the proximal recess of the stopper 494 at the proximal portion of the drug barrel. The base column 482 is incorporated into the hollow cap 484, the base portion 488 engages the stopper 494, and the leg 498 is disposed outside the proximal end of the barrel.

[0086] During operation, as shown in FIGS. 81A and 81B, the cap 484 is displaced distally relative to the base column 482 (as well as the stopper 494 and the barrel) until the proximal end of the cap 484 is flush with the end of the drug barrel. This operation causes the leg 498 to engage the inner surface of the barrel and displace radially inward, thereby bringing the ratchet teeth 492 into a locked engagement with the ratchet teeth 497. The engagement of the locking barb 493, the ratchet teeth 492 and 497, and the engagement of the leg 498 with the inner surface of the barrel prevent displacement of the cap 484 relative to the base column 482. Thus, the automatic adjustment spacer 486 can accommodate differences in the stopper, barrel diameter, and drug filling amount, and automatically provides a flat support surface with the proximal end of the drug barrel.

[0087] One aspect of the present invention is a spacer assembly 486 disposed relative to a stopper within a container in a system. The design of the spacer is such that its effective length can be adjusted to enable the administration of an accurate amount of drug. The adjustment of the length is intended to compensate for manufacturing tolerances within the container, filling amount, particularly the length of the stopper, and is one-third of the dosage variation using a non-adjustable spacer. The length of the spacer can be adjusted by several techniques depending on the particular aspect. The length of the spacer can self-adjust based on its position at the rear of the container, can be adjusted by an assembly device during final assembly of the primary container sub-assembly, can be formed as an integral part of the stopper, and can be adjusted as a sub-assembly before filling. The adjustable spacer 486 allows a more accurate amount of fluid to be injected compared to a non-adjustable stopper.

[0088] Referring to FIGS. 82 to 87, a drive assembly 500 for a drug delivery system according to an aspect of the present invention is shown. The drive assembly 500 includes an actuation button 506, a container 508, a needle actuator assembly 510, an actuation release or flipper 512, a lead screw 514, and a plunger 516. The lead screw includes a drum portion 518 having radially projecting external vanes 520, best shown in FIGS. 84 and 85, and includes a threaded portion 522, which will be described in more detail subsequently. Prior to actuation, as best shown in FIGS. 83 and 86, one end 513 of the actuation release 512 engages one of the vanes 520 to prevent rotation of the lead screw 514.

[0089] According to one aspect, as shown in FIGS. 84 to 86, the threaded portion 522 of the lead screw 514 engages an internal thread of a nut 524 connected to the plunger 516. According to another aspect, the nut and its internal thread are integrally formed with the plunger as a single structure. Further, a constant force spring 526 is received within the drum portion 518 to bias the lead screw 514 in the rotational direction. According to one aspect, the spring 526 is fixed to the base cover 504. According to another aspect, as shown in FIGS. 84 to 86, a drive assembly housing 528 is disposed within the system and the spring 526 is fixed to the power pack housing 528.

[0090] Unlike a helical spring, such as a compression spring, which has a force profile proportional to its displacement, a constant force spring 526, etc., maintains a relatively flat or uniform force profile over a long actuation length. A uniform force profile advantageously provides an ejection force proportional to the spring force. This provides a flat or uniform injection force and thus a substantially constant injection rate of the drug. The spring 526 is shown in FIG. 86 as having only two turns of material, but those skilled in the art will understand that fewer or more turns may be used. Preferably, the assembler winds the spring 526 when the drive assembly 500 is assembled, and the spring 526 is stored in the wound position until actuation.

[0091] In operation of the system, the needle actuator assembly 510 is released and displaced axially from a pre-use position to a post-use position (to the right in FIGS. 82-85) under the influence of the biasing member 530 (best shown in FIG. 83). During this displacement, the needle actuator assembly 510 abuts against the second end 532 of the actuating release 512 and rotates the release 512 counterclockwise as shown in FIG. 87. This counterclockwise rotation of the actuating release 512 disengages its first end 513 from engagement with the vane 520. Following the disengagement of the first end 513 from the vane 520, the spring 526 is wound back and drives the rotation of the lead screw 514 which, in combination with the nut 524, advances the plunger 516 to dispense the drug.

[0092] When the lead screw 514 is rotating, the rotation of the drum portion 518 and the vane 520 is visible through the window 534 in the housing. This window 534 indicates the progress of the screw in a much more obvious way than observing the linear movement of the stopper 536 within the container 508. In fact, this rotational movement is many times more sensitive than the linear movement. One skilled in the art will understand that the exact amount of advantage or enhancement depends on the pitch of the threaded portion 522 of the lead screw 514, the diameter of the drum portion 518, and the number of vanes 520 on the drum portion 518.

[0093] Referring to FIGS. 88-93, a drive assembly 600 for a drug delivery system according to a further aspect of the present invention is shown. The drive assembly 600 acts to store the mechanical energy of a spring and activate it when triggered. The drive assembly 600 includes a drug barrel 601, a stopper 602 slidably disposed within the barrel 601, a first valve plunger 603, a second valve plunger 604, a first rotating nut 605, and a second rotating nut 606. The drive assembly 600 also includes a rotary indicator 607, a locking element 608, a constant force spring 609 disposed within the rotary indicator 607, and an actuating release or flipper 610. The drive assembly 600 is at least partially disposed within a housing 611 that can be assembled into the drug delivery system.

[0094] A constant force spring 609 is housed between a housing 611 and a rotary indicator 607 within a drum portion 616 of the rotary indicator 607. The non - operating state of the drive assembly is such that energy is applied by winding back the spring 609 and this energy is geometrically utilized by the housing 611, the rotary indicator 607, and the deactivation 610. When the drive assembly 600 is deactivated, the spring returns and converts mechanical energy into rotational movement of the rotary indicator.

[0095] The nested multi - part plunger is oriented along the force axis between a drug barrel 601 and a rotary indicator 607. The rotary indicator 607 features a threaded shaft 618. According to one aspect, the thread is a composite thread and is essentially either square or rectangular. The nested multi - part plunger includes a threaded nut consisting of two parts (a first rotary nut 605 and a second rotary nut 606) and a plunger consisting of two parts (a first valve plunger 603 and a second valve plunger 604). The second rotary nut 606 is a threaded shaft that meshes with the rotary indicator 607 and the first rotary nut 605, and is characterized by corresponding threads (inner and outer threads respectively) on its inner and outer surfaces for meshing with them. The second rotary nut 606 also has, at its proximal end, a circular collar 620 (best shown in FIG. 92) that seats on the second valve plunger 604. The second rotary nut 606 rotates freely along the force axis. The first rotary nut 605 is also a threaded shaft characterized by threads at its inner diameter corresponding to the outer threads of the second rotary nut 606 so as to mesh with the second rotary nut 606.

[0096] According to one aspect, at one end, the first rotary nut 605 has a hexagonal collar that is press - fitted into the first valve plunger 603, fixedly connecting the first valve plunger 603 to the first rotary nut 605. In the drive assembly 600, the first rotary nut will not rotate freely and will only translate when the power module sub - assembly is actuated.

[0097] The second valve plunger 604 is a hollow cylindrical component having a small collar 622 at its distal end, a large collar 624 at its proximal end, and an elongated L-shaped arm 626 (best shown in FIG. 93) protruding from the large proximal collar 624. According to one embodiment, the small collar is discontinuous and features four cantilever arms or leaf springs 623 that allow the collar to be bent and engaged with the first valve plunger 603. The inner surface of the second valve plunger 604 terminates with an undercut shelf 628 that projects radially inward of the large collar 624 at its proximal end throughout its length. The shelf 628 engages with the second rotary nut 606 within the telescoping assembly.

[0098] The first valve plunger 603 is a hollow cylindrical component that is attached to the stopper 602 and mates with the second valve plunger 604. More specifically, the first valve plunger 603 features a cylindrical protrusion 630 that mates with the stopper 602 at its distal end. According to one aspect, as shown in FIG. 89, four through slots 632 are disposed in the proximal quadrant of the first valve plunger 603 to engage with the leaf springs or arms 623 and the small collar portion 622 of the second valve plunger 604. The first and second valve plungers 603 and 604 are both slidable.

[0099] Telescoping is achieved when the biasing spring 609 returns rearward and the rotation indicator 607 begins to rotate. The threaded attachment between the rotation indicator 607 and the second rotary nut 606 causes the second rotary nut 606 to rotate. However, since the second rotary nut 606 is screwed into the first rotary nut 605, and the first rotary nut 605 cannot rotate due to the pressure caused by the agent within the barrel 601 and experiences resistance to distal movement, the second rotary nut 606 is displaced proximally and bottoms out on a ledge 628 that projects radially inward of the second valve plunger. The second valve plunger 604 is prevented from moving proximally by the housing 611. Thereafter, with continued rotation of the rotation indicator 607, since the second rotary nut 606 is threaded onto the non-rotatable first rotary nut 605, the first rotary nut 605 moves distally, pushing the first valve plunger 603 (and the stopper 602) to dispense the agent from the barrel 601.

[0100] The first valve plunger 603 is displaced distally relative to the second valve plunger 604 until small collar portions 622 (respectively disposed at the distal ends of the leaf springs or arms 623 of the second valve plunger 604) engage corresponding proximal ends of slots 632 in the first valve plunger 603. This locks the relative positions of the first and second valve plungers 603 and 604, and with continued rotation of the rotation indicator 607, both valve plungers translate distally and the second rotary nut also advances together (due to its proximal engagement with the ledge 624).

[0101] The initial and final positions of the nested plunger, and thus the drug dosage, are controlled by the rectangular thread shape of the screw shaft 618 of the rotary indicator 607, the threaded shaft on the drum portion 616 of the rotary indicator 607, and the stepped pin that functions as the locking element 608. According to one aspect, the threaded shaft on the drum portion 616 of the rotary indicator 607 has a single thread pitch, while the remaining components within the nested chain have a double thread pitch, so the axial movement of the other threaded components is twice the axial movement of the lock 608 relative to the rotary indicator.

[0102] According to one embodiment, the lock 608 is cylindrical and features a domed tip at one end and a cylindrical collar at the other end. The threads on the outside of the drum portion 616 of the rotary indicator and the undercut 636 at the bottom of the housing 611 capture the lock 608 in a predetermined position and allow it to slide parallel to the force axis. Thus, when the spring 609 is released and the rotary indicator 607 rotates, the lock 608 also translates and produces a secure stop when it reaches the distal end of the thread on the outside of the drum portion 616 of the rotary indicator.

[0103] One advantage of the aspect of the drive assembly 600 includes the use of a constant force spring 609, the mechanical energy of which is converted into a substantially constant linear force with respect to the drug within the barrel 601. Further, this results in a uniform drug delivery rate. Another advantage is the use of a nested plunger driven in a threaded shape, and the drive assembly can provide space savings in a straight line of up to 0.75 inches compared to other plunger designs. Further, the drive assembly provides a controlled drug dosage due to the initial and final mechanical constraints within the same components.

[0104] As described above, other drug delivery systems utilize a compression coil spring, which exerts maximum force during actuation and that force eventually decreases as the spring expands. The decreasing force on the plunger is translated into variable drug delivery times and drug outlet pressures. By using a constant force spring, the force acting on the plunger is constant from the beginning to the end of dosing. Further, in addition to the non-changing length of the plunger that requires translation within the drug container, the distance the coil spring has to travel can create a long assembly. In contrast, in embodiments of the present invention, the constant force spring is radially accommodated and does not require additional space before or after actuation. Further, the nested plunger aspect allows the length of the plunger in the container to be significantly shortened compared to the non-changing length of the plunger.

[0105] Conventional drug delivery systems have variable dosing accuracy because the mechanical components that enable drug delivery create geometric dependencies by bottoming out in the container, and they cannot be manufactured with tight tolerances. Some embodiments of the present invention generate control over the start and end times of the translational plunger via the thread shape in the rotary indicator and the use of a constant force spring.

[0106] The drive assembly creates a space-saving geometric arrangement in addition to well-controlled time, volume, and pressure for the drug delivery device, which results in a more attractive, compact, and accurate drug delivery device.

[0107] Some aspects of the drive assembly implement three rotating threaded shafts to save approximately 0.75 inches of linear space. In other aspects, the same concept can be employed using two rotating threaded shafts, resulting in a space savings of approximately 0.5 inches. Some aspects of the present invention convert the rotational energy of a constant force spring into the translational force motion of the plunger.

[0108] Referring to FIGS. 94 - 100, a spacer assembly 660 according to a further aspect of the present invention is shown. The spacer assembly 660 is similar to the spacer assembly 460 described above and shown in FIGS. 76 - 78 and operates in a similar manner to achieve similar advantages. The spacer assembly 660 includes a fixed spacer 666 and an adjustable spacer 668. The fixed spacer 666 is received by a stopper 462 and is configured such that a protrusion 670 engages the stopper 462 to fix the fixed spacer 666 within the stopper 462, although other suitable fixing configurations such as threads may be utilized. The fixed spacer 666 includes an inner thread 672 that receives an outer thread 678 of the adjustable spacer 668. The fixed spacer 666 includes a plurality of detents 674 disposed in a helical portion of the fixed spacer 666. The adjustable spacer 668 includes a spring detent arm 676 that engages one of the detents 674 and prevents rotational and axial displacement of the adjustable spacer 668 relative to the fixed spacer 666. The spring detent arm 676 is shaped and configured to pass over the detent 674 in one direction to allow rotational and axial displacement of the adjustable spacer 668 from the fixed spacer 666. The adjustable spacer 668 can initially be locked to the fixed spacer 666 via the threads 672, 678 by applying a force to the top of the spring detent arm 676, which moves the spring detent arm 676 away from the detent 674 and allows the spacers 666, 668 to be fixed to each other. Thus, in the same manner as described above with respect to the spacer assembly 460, the adjustable spacer is free to rotate in one axial direction to adjust the length of the spacer assembly 660.

[0109] Referring again to FIGS. 94-100, the spacer assembly 660 further includes a shim 680 configured to be received and fixed within an adjustable spacer 668. Instead of providing adjustable spacers 468, 668 of multiple sizes, multiple shim 680 sizes may be provided to accommodate multiple different fill volumes within the container 14. The shim 680 may be fixed to the adjustable spacer 668 via a connector 682 extending from the shim 680 received by the adjustable spacer 668 using a snap fit, although other suitable fixing configurations may be utilized. The central portion 684 of the fixed spacer 666 is configured to engage to prevent rotation of the adjustable spacer 668 with the fixed spacer 666 while the adjustable spacer 668 rotates relative to the fixed spacer 666. The central portion 684 of the fixed spacer 666 is accessible through an opening of the shim 680.

[0110] Elements of one disclosed aspect may be combined with elements of one or more other disclosed aspects to form different combinations, all of which are considered to be within the scope of the invention.

[0111] This disclosure has been described as having exemplary designs, but the present disclosure may be further modified within the spirit and scope of this disclosure. Accordingly, this application is intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover departures from the present disclosure that come within known or customary practice in the art to which this disclosure pertains and fall within the scope of the appended claims.

Claims

1. A drug delivery system, wherein the drug delivery system comprises: a container configured to hold a drug; a needle; a valve assembly configured to pierce a closure portion of the container to place the container in fluid communication with the needle; a stopper configured to move within the container to dispense the drug from the container to the needle; a drive assembly configured to move the stopper within the container, the drive assembly comprising: a first plunger member configured to move axially between a pre-use position, a use position, and a post-use position; a second plunger member received within the first plunger member; a plunger actuating member configured to engage and disengage the first plunger member; a first biasing member disposed between the second plunger member and the plunger actuating member and configured to move the stopper within the container; a second biasing member disposed between the second plunger member and the first plunger member and configured to drive the first plunger member against the stopper and to move the container to engage the valve assembly; wherein the second plunger member is configured to move axially after the first plunger member has moved a predetermined axial distance.

2. The drug delivery system according to claim 1, wherein the plunger actuating member is rotatably movable relative to the first plunger member between a first rotational position and a second rotational position; wherein the plunger actuating member includes a plurality of protrusions configured to be received by a plurality of slots or notches defined by the first plunger member; wherein at the first rotational position of the plunger actuating member, the plurality of protrusions and the plurality of slots or notches are not aligned, and the plunger actuating member engages the first plunger member to prevent movement of the first plunger member and the second plunger member, and the first biasing member and the second biasing member bias the first plunger member and the second plunger member away from the plunger actuating member. In the second rotational position of the plunger actuating member, the plurality of protrusions and the plurality of slots or notches are aligned with each other, and the plunger actuating member is disengaged from the first plunger member, enabling movement of the first plunger member and the second plunger member. A drug delivery system characterized by this.

3. The drug delivery system according to claim 2, further comprising a needle actuator assembly configured to engage with a driving surface of the plunger actuating member and move the plunger actuating member from the first rotational position to the second rotational position. A drug delivery system characterized by this.

4. The drug delivery system according to claim 3, wherein the driving surface includes a plurality of gears. A drug delivery system characterized by this.

5. The drug delivery system according to claim 1, wherein the first plunger member forms a nested structure with the second plunger member. A drug delivery system characterized by this.

6. The drug delivery system according to claim 1, wherein each of the first biasing member and the second biasing member includes a compression spring. A drug delivery system characterized by this.

7. The drug delivery system according to claim 1, wherein the first biasing member is constrained between the plunger actuating member and a first spring seat of the second plunger member. A drug delivery system characterized by this.

8. The drug delivery system according to claim 1, wherein the second biasing member is constrained between a second spring seat of the second plunger member and the first plunger member. A drug delivery system characterized by this.

9. The drug delivery system according to claim 1, wherein the second biasing member is harder than the first biasing member. A drug delivery system characterized by this.

10. The drug delivery system according to claim 2, wherein the first rotational position is 15 degrees from the second rotational position. A drug delivery system characterized by this.

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