autoinjector

Abstract

An autoinjector includes a housing extending along a longitudinal axis having a proximal end and a distal end. A needle extends at least partially from the distal end of the housing. A needle guard assembly is coupled to the housing. The needle guard has a needle guard extension that is moveable relative to the housing distally along the longitudinal axis from a retracted position where the needle extends distally past the needle guard extension and an extended position where the needle guard extension extends distally past the needle. A retainer is coupled between the needle guard extension and the housing to retain the needle guard extension relative to the housing in a blocking position and is moveable relative to the housing to an unblocked position to allow the needle guard extension to move relative to the housing to the extended position.

Description

Docket No. 063995-01-5097-WOTITLE

[0001] AutoinjectorCROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 698,732 filed September 25, 2024 entitled “Autoinjector”, which is incorporated by reference herein in its entirety.TECHNICAL FIELD

[0003] The present disclosure generally relates to autoinjectors and, in some embodiments, to autoinjectors for the delivery of large volumes of medicament for sub-skin surface penetration.SUMMARY

[0004] In one embodiment, there is an autoinjector having a housing extending along a longitudinal axis having a proximal end and a distal end, a needle extending at least partially from the distal end of the housing, a needle guard assembly coupled to the housing having a needle guard extension moveable relative to the housing distally along the longitudinal axis from a retracted position where the needle extends distally past the needle guard extension and an extended position where the needle guard extension extends distally past the needle, and a retainer coupled between the needle guard extension and the housing retaining the needle guard extension relative to the housing in a blocking position and moveable relative to the housing to an unblocked position to allow the needle guard extension to move relative to the housing to the extended position.

[0005] In some embodiments, there is a needle guard body disposed within the housing having an engagement surface defined thereon. In some embodiments, the needle guard extension includes a flexible leg that slidably engages the engagement surface when the needle guard extension is moved distally from the retracted position to the extended position. In some embodiments, the flexible leg is moveable between a neutral position where the flexible leg extends substantially along the longitudinal axis and a flexed position where the flexible leg flexes radially outward from the longitudinal axis. In some embodiments, the engagement surface temporarily moves the flexible leg from the neutral position to the flexed position when the needle guard extension is moved distally from the retracted position to the extended position.

[0006] In some embodiments, the needle guard body further includes a recess defined thereon proximate the engagement surface. In some embodiments, the recess is configured to receive at least a portion of the flexible leg therein when the flexible leg advances distally past the engagement surface. In some embodiments, engagement of the recess and the flexible leg couples the needle guard body and the needle guard extension.

[0007] In some embodiments, a needle guard spring disposed between the needle guard extension and the needle guard body is configured to move the needle guard extension from the retracted position to the extended position. In some embodiments, the retainer prevents proximal movement of the needle guard assembly relative to the housing when the retainer is in the unblocked position. In some embodiments, the retainer is further moveable relative to the housing to an active position where the retainer allows proximal movement of the needle guard assembly relative to the housing. In some embodiments, the retainer is moveable relative to the housing by a user. In some embodiments, the needle guard assembly is moveable proximally relative to the housing to expose at least a portion of the needle.

[0008] In some embodiments, the autoinjector further includes a trigger disposed within the housing, a latch disposed within the housing, the latch configured to engage the trigger, a ram moveable relative to the latch, and an energy source configured to urge the ram distally relative to the latch along the longitudinal axis. In some embodiments, proximal movement of the needle guard assembly causes the needle guard assembly to engage the trigger to activate the energy source.

[0009] In some embodiments, an adjustment interface extends radially therefrom. In some embodiments, the adjustment interface is engaged by a user to move the retainer relative to the housing from the blocking position to the unblocked position to the active position. In some embodiments, the housing includes a guide extending therethrough. In some embodiments, the adjustment interface extends through the guide.

[0010] In some embodiments, the guide engages the adjustment interface at a first end and a second end thereof to restrict movement of the retainer about the longitudinal axis relative to the housing. In some embodiments, the adjustment interface is positioned proximate the first end of the guide when the retainer is in the blocking position and is positioned proximate the second end of the guide when the retainer is in the active position.

[0011] In some embodiments, the needle guard extension is rotatable relative to the housing about the longitudinal axis between a locked position where the needle guard extension is prevented from moving relative to the housing and an unlocked position where the needle guard extension is allowed to move relative to the housing. In some embodiments, the retainer is rotationally coupledto the needle guard extension and configured to move the needle guard extension relative to the housing about the longitudinal axis from the locked position to the unlocked position.

[0012] In some embodiments, the needle guard body includes a blocking member configured to engage the needle guard extension to prevent distal movement of the needle guard extension. In some embodiments, rotation of the needle guard extension relative to the housing about the longitudinal axis from the locked position to the unlocked position disengages the needle guard extension from the blocking member of the needle guard body allowing the needle guard extension to move relative to the housing from the retracted position to the extended position. In some embodiments, the flexible leg and the recess are aligned along the longitudinal axis in the unlocked position and are not aligned along the longitudinal axis in the locked position.

[0013] In some embodiments, the autoinjector further includes a medicament container disposed within the housing and containing a medicament. In some embodiments, the needle is fluidly coupled to the medicament container.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The foregoing summary, as well as the following detailed description of embodiments of the autoinjector will be better understood when read in conjunction with the appended drawings of exemplary embodiments. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

[0015] In the drawings:

[0016] Fig. 1 is a perspective view of an autoinjector in accordance with a first exemplary embodiment of the present invention;

[0017] Fig. 2 is a front view of the autoinjector of Fig. 1 shown with a transparent housing, a retainer in a blocking position and a luer plug coupled thereto;

[0018] Fig. 3 is a partial magnified view of the autoinjector of Fig. 2;

[0019] Fig. 4 is a front view of the autoinjector of Fig. 1 shown with a transparent housing, a retainer in a blocking position and a needle coupled thereto;

[0020] Fig. 5 is a partial magnified view of the autoinjector of Fig. 4;

[0021] Fig. 6 is a front view of the autoinjector of Fig. 1 shown with a transparent housing, a retainer in an unblocking position and an extended needle guard;

[0022] Fig. 7 is a partial magnified view of the autoinjector of Fig. 6;

[0023] Fig. 8 is a front view of the autoinjector of Fig. 1 shown with a transparent housing, a retainer in an active position and an extended needle guard;

[0024] Fig. 9 is a partial magnified view of the autoinjector of Fig. 8;

[0025] Fig. 10 is a front view of the autoinjector of Fig. 1 shown with a transparent housing, a retainer in an active position and a retracted needle guard;

[0026] Fig. 11 is a cross-sectional view of the autoinjector of Fig. 10;

[0027] Fig. 12 is a front view of the autoinjector of Fig. 1 shown with a transparent housing, a retainer in an active position and a needle guard extending therefrom in a lockout position;

[0028] Fig. 13 is a cross-sectional view of the autoinjector of Fig. 12;

[0029] Fig. 14 is a perspective view of the needle guard extension of the autoinjector of Fig. 1;

[0030] Fig. 15 is a perspective view of the needle guard body of the autoinjector of Fig. 1;

[0031] Fig. 16 is a perspective view of the retainer of the autoinjector of Fig. 1;

[0032] Fig. 17 is a perspective view of a front housing of an autoinjector in accordance with a second exemplary embodiment of the present invention;

[0033] Fig. 18 is a front view ofthe autoinjector of Fig. 17 shown with a transparent front housing, a retainer in a blocking position and a luer plug coupled thereto;

[0034] Fig. 19 is a partial magnified view of the autoinjector of Fig. 18;

[0035] Fig. 20 is a front view of the autoinjector of Fig. 17 shown with a transparent front housing, a retainer in a blocking position and a needle coupled thereto;

[0036] Fig. 21 is a partial magnified view of the autoinjector of Fig. 20;

[0037] Fig. 22 is a front view of the autoinjector of Fig. 17 shown with a transparent front housing, a retainer in an unblocking position and an extended needle guard;

[0038] Fig. 23 is a partial magnified view of the autoinjector of Fig. 22;

[0039] Fig. 24 is a front view of the autoinjector of Fig. 17 shown with a transparent front housing, a retainer in an active position and an extended needle guard;

[0040] Fig. 25 is a partial magnified view of the autoinjector of Fig. 24;

[0041] Fig. 26 is a front view of the autoinjector of Fig. 17 shown with a transparent front housing, a retainer in an active position and a retracted needle guard;

[0042] Fig. 27 is a perspective view of the needle guard extension of the autoinjector of Fig. 17;

[0043] Fig. 28 is a perspective view of the needle guard body of the autoinjector of Fig. 17; and

[0044] Fig. 29 is a perspective view of the retainer of the autoinjector of Fig. 17.DETAILED DESCRIPTION

[0045] The present disclosure generally relates to autoinjectors, needle guard and / or button actuated triggering devices that are used in the delivery of large volumes (e.g., 10 mL or larger doses) of injectable fluid, such as medicament, for sub-skin surface penetration (e.g., subcutaneous and intramuscular injections). Devices that deliver large volumes of medicament are often prone to configuration restrictions as the delivery volume of the medicament increases, such as spring force limitations and syringe container breakage. Due to the current configurations of overall device design, and the limitations of the biological uptake factors that limit injection speed and volume, injection devices are often held by the user during injection for long durations, and can result in other delivery methods being used such as on-body delivery systems, which are attached to the patient during delivery.

[0046] Increasingly, biologies are allowing for at-home administration for patients. However, for many biologies, large doses and the resulting large volume of medicament that must be delivered often precludes self-administration because of the length of time required to hold the delivery device in place during injection. Protein hyper-concentration may be used to reduce injection volume in certain instances, but the resulting medicament often has a much higher viscosity than the traditional biologies. High-powered autoinjectors may allow delivery of these hyper-concentrated proteins. However, handheld autoinjector designs may still only allow for up to 2.5 mL of a viscous medicament to be injected within 30 seconds.

[0047] With the development of enzymes that locally degrade hyaluronan (HA) in the subcutaneous (SC) space, thereby temporarily removing a barrier to fluid flow, the traditional limitations of biological uptake factors that limit injection speed and volume may be reduced. As such, higher volumes of viscous medicaments may be delivered. Accordingly, there is a need to provide a handheld device capable of delivering a large dose (e.g., at least 3 mL, at least 5 mL, at least 10 mL, at least 20 mL or at least 50 mL) of a viscous medicament in a delivery time appropriate for a handheld device.

[0048] The delivery of large dose injections poses challenges due to factors like bulging and leak back. The delivery of large dose injections becomes challenging as the expansion of soft tissues, or bulging, may occur, leading to discomfort and potential tissue damage at the injection site. Further, the issue of unintended escape of medication from the injection site due to pressure buildup or improper sealing (e.g., leak back) arises, jeopardizing the accuracy of dosing and the overall efficacy of the administered medication as the fluid may escape from the injection site. To overcome suchissues, drug delivery technology of large doses of a viscous medicament often utilizes the proprietary recombinant human hyaluronidase PH20 enzyme (e.g., rHuPH20; Halozyme, Inc.) that facilitates SC delivery of co-administered therapeutics. rHuPH20 works by degrading the HA, which plays a role in resistance to bulk fluid flow in the SC space, limiting large volume SC drug delivery, dispersion, and absorption. Co-administration of rHuPH20 with injectable therapies can overcome administration time and volume barriers associated with existing SC therapeutic formulations and has been shown to reduce the burden on patients and healthcare providers compared with intravenous formulations. rHuPH20 has countless applications in the current field of injectable therapies by increasing the dispersion and absorption of other injected drugs, such as anticancer therapies (e.g., trastuzumab and rituximab), immunodeficiency treatment, in subcutaneous urography for improving resorption of radiopaque agents, and fluid delivery for rehydration.

[0049] A common feature of autoinjectors is the inclusion of needle guards, which serve to reduce the risk of needle-stick injuries and protect the integrity of the needle before use. However, when using luer lock needles, a common connection system between the needle and the medicament container, the needle guard can obstruct the user’s view of the connection point. This obstruction increases the risk of improper attachment, which can compromise dose accuracy and patient safety.

[0050] Referring to the drawings in detail, wherein like reference numerals indicate like elements throughout, there is shown in Figs. 1-13 an autoinjector, generally designated 100, in accordance with an exemplary embodiment of the present invention. As described in more detail below, the autoinjector 100 may include a housing 102, a needle 104 extending at least partially from the housing 102, a needle guard assembly 106 moveable relative to the housing 102 and a retainer 108 that selectively retains the needle guard assembly 106 relative to the housing 102. The needle guard assembly 106 may be retracted relative to the housing 102 (Figs. 2-5) until the retainer 108 is manipulated by a user to extend the needle guard assembly 106 past the needle 104 (Figs. 6-9). The autoinjector 100 may allow a user to view the needle 104 clearly (e.g., during coupling of a needle 104 to a medicament container 122 disposed within the housing 102) when the needle guard assembly 106 is retracted and may maintain the protective benefits of the needle guard assembly 106 when extended past the needle 104.

[0051] Referring to Fig. 1, the housing 102 may extend along a longitudinal axis LA between a proximal end and a distal end opposite the proximal end. The housing 102 may be configured for allowing a user to grip or handle the autoinjector 100. The housing 102 may be shaped to fit into a user’s hand for single-handed function. The housing 102 may have a generally circular cross section. In some embodiments, the housing 102 has an ovular cross-section to help position theautoinjector 100 in the user’s hand or to prevent the autoinjector 100 from rolling while on a surface. The housing 102 may substantially house the components shown in Figs. 2-16.

[0052] Referring to Fig. 1 , the housing 102 may comprise a front housing 110 and a rear housing 112. For assembly purposes, the front housing 110 and rear housing 112 may be coupled together by snap-fit coupling. In some embodiments, the front housing 110 and rear housing 112 are coupled using an adhesive or other suitable means to prevent separation during use of the autoinjector 100. In some embodiments, the front housing 110 and rear housing 112 are integrally formed together during manufacturing or assembly of the autoinjector 100. The housing 102 may be formed from a plastic with sufficient rigidity to prevent outside forces from interfering with the interactions of the internal components of the autoinjector 100.

[0053] When coupled to one another, the front housing 110 and the rear housing 112 may be fixed relative to each other. The front housing 110 may include a front engagement component 114 defined thereon. The front engagement component 114 may extend radially outward from the front housing 110. In some embodiments, the front engagement component 114 may extend radially inward from the front housing 110. The rear housing 112 may include a rear engagement component 116 defined thereon. The rear engagement component 116 may be an aperture extending through the rear housing 112. The rear engagement component 116 may be shaped and sized to receive the front engagement component 114 when the front housing 110 and the rear housing 112 are coupled together. Engagement of the front engagement component 114 and the rear engagement component 116 may prevent the front housing 110 from moving relative to the rear housing 112. In some embodiments, the rear engagement component 116 extends radially inward or radially outward from the rear housing 112. In some embodiments, the front engagement component 1 14 is an aperture extending through the front housing 110.

[0054] As shown in Figs. 1-13, the front housing 110 may include a housing recess 120 defined thereon. The housing recess 120 may be defined on the distal end of the housing 102 and may extend proximally along the longitudinal axis LA to enable a user to inspect a connection between the needle 104 and a medicament container 122 disposed in the front housing 110. The housing recess 120 may be generally rectangular. The front housing 110 may include a plurality of housing recesses 120. In some embodiments, the front housing 110 includes one housing recess 120. The front housing 110 may include a guide 124 defined thereon. The guide 124 may extend through the housing 102. The guide 124 may be a generally rectangular aperture that extends around a portion of the circumference of the front housing 110. The housing 102 may include one guide 124. In some embodiments, the housing 102 includes a plurality of guides 124. At least a portion of the retainer 108may extend through the guide 124. The guide 124 may limit movement of the retainer 108 relative to the housing 102, as described in more detail below.

[0055] A user of the autoinjector 100 may need to observe the volume of a medicament container therein before or during an injection. Referring to Fig. 1, the front housing 110 may include a window 118 defined therein. The window 118 may be a generally ovular aperture extending through the front housing 110. In some embodiments, the window 118 is circular or rectangular. The window 118 may include a transparent film extending across the aperture defining the window 118. The film may be a transparent plastic or glass. In some embodiments, the window 118 does not include a film.

[0056] As shown in Figs. 2-15, the needle guard assembly 106 may be coupled to the housing 102. The needle guard assembly 106 may have a needle guard extension 126 moveable relative to the housing 102 distally along the longitudinal axis LA and a needle guard body 128 disposed within the housing 102. The needle guard extension 126 may be moveable relative to the housing 102 from a retracted position where the needle 104 extends distally beyond the needle guard extension 126 and an extended position where the needle guard extension 126 extends distally past the needle 104. The needle guard extension 126 may be moveable relative to the needle guard body 128 from the retracted position to the extended position and may be coupled to the needle guard body 128 in the extended position.

[0057] As shown in Figs. 11 and 13, the needle guard assembly 106 may include a needle guard spring 130 disposed between the needle guard extension 126 and the needle guard body 128. The needle guard spring 130 may be configured to move the needle guard extension 126 relative to the needle guard body 128 from the retracted position to the extended position. The needle guard spring 130 may engage a distal end of the needle guard body 128 and a distal end of the needle guard extension 126. The needle guard spring 130 may be prevented from moving the needle guard extension 126 relative to the needle guard body 128 from the retracted position to the extended position by the retainer 108, as described in more detail below.

[0058] As shown in Fig. 14, the needle guard extension 126 may be a generally cylindrical member extending along the longitudinal axis LA between a proximal end and a distal end. The needle guard extension 126 may be disposed within the housing 102. The needle guard extension 126 may be disposed between the needle guard body 128 and the housing 102. In some embodiments, the needle guard body 128 is disposed between the needle guard extension 126 and the housing 102. The needle guard extension 126 may include an extension body 132 and at least one extension arm 134 extending proximally therefrom. The extension body 132 may be a cylindrical member with an opendistal end that is shaped and sized to receive at least a portion of the needle guard body 128 therein when the needle guard extension 126 is in the retracted position. The extension body 132 may have an open distal end that is shaped and sized to allow the needle 104 to pass therethrough.

[0059] As shown in Fig. 14, the needle guard extension 126 may have two extension arms 134. In some embodiments, the needle guard extension 126 has one extension arm 134. The extension arm 134 may be a generally rectangular member extending proximally from a proximal end of the extension body 132. The extension arm 134 may have a curvature about the longitudinal axis LA similar to a curvature of the extension body 132. The extension arm 134 may be able to flex relative to the extension body 132 such that the proximal end of the extension arm 134 may move radially in response to a force acting thereon. The extension arm 134 may be comprised of an elastic material allowing it to flex and deflect back to its original shape and position when the force is removed.

[0060] The extension arm 134 may include an extension recess 136 defined thereon. The extension recess 136 may be a generally rectangular recess. In some embodiments, the extension recess 136 is a rounded or polygonal recess. The extension recess 136 may be defined on an outer surface of the extension arm 134 and may extend across a portion of the width of the extension arm 134. In some embodiments, the extension recess 136 extends across the width of the extension arm 134. In some embodiments, the extension recess 136 is defined on an inner surface of the extension arm 134.

[0061] As shown in Fig. 14, the needle guard extension 126 may have a flexible leg 138 extending distally therefrom. The needle guard extension 126 may have two flexible legs 138 extending distally therefrom. In some embodiments, the needle guard extension 126 has one flexible leg 138 extending distally therefrom. The flexible leg 138 may extend proximally from the proximal end of the extension arm 134. The flexible leg 138 may include a foot 140 disposed thereon. The foot 140 may extend from the flexible leg 138 outward about the longitudinal axis LA relative to the extension arm 134. In some embodiments, the flexible leg 138 extends inward about the longitudinal axis LA relative to the extension arm 134. The flexible leg 138 may be moveable between a neutral position where the flexible leg 138 extends substantially along the longitudinal axis LA and a flexed position where the flexible leg 138 flexes radially outward from the longitudinal axis LA. In some embodiments, the flexible leg 138 flexes inward about the longitudinal axis LA relative to the extension arm 134 in the flexed position.

[0062] As shown in Fig. 15, the needle guard body 128 may be a generally cylindrical member extending along the longitudinal axis LA between a proximal end and a distal end. The needle guard body 128 may include at least one body arm 142 extending distally therefrom. The needle guardbody 128 may be shaped and sized to be disposed within the needle guard extension 126. The needle guard body may be open at both the distal end and proximal end to allow other components of the autoinjector 100 to be disposed therein (e g., the medicament container 122).

[0063] The needle guard body 128 may have two body arms 142 extending distally therefrom. The needle guard body 128 may be disposed within the housing. The body arm 142 may be a generally rectangular member extending distally from the needle guard body 128. The body arm 142 may have a curvature about the longitudinal axis LA similar to a curvature of the needle guard body 128. The body arm 142 may have a body arm protrusion 148 defined thereon. The body arm protrusion 148 may be a generally cubical member extending radially from the body arm 142. The body arm protrusion 148 may be shaped and sized to be received by another component of the autoinjector 100 to couple the needle guard assembly 106 thereto, as described in more detail below. The body arm 142 may have a body arm knob 152 defined thereon. The body arm knob 152 may be a generally cubical member extending radially from the body arm 142.

[0064] As shown in Fig. 15, the needle guard body 128 may have an engagement surface 144 defined thereon. The engagement surface 144 may be defined on the body arm 142. The engagement surface 144 may extend radially outward from the body arm 142 and may be angled such that an extension of the engagement surface 144 increases from a proximal end toward a distal end. The needle guard body 128 may have a recess 146 defined thereon. The recess 146 may be located proximate the engagement surface 144. The recess 146 may be defined on one side by the distal end of the engagement surface 144. In some embodiments, the recess 146 is defined in the engagement surface 144. The recess 146 may be shaped and sized to receive at least a portion of the flexible leg 138 therein when the needle guard extension 126 is moved relative to the needle guard body 128 from the retracted position to the extended position by the needle guard spring 130. The recess 146 may receive the foot 140 of the flexible leg 138 therein.

[0065] As shown in Fig. 16, the retainer 108 may be a generally cylindrical member extending along the longitudinal axis LA between a proximal end and a distal end. The retainer 108 may have an open proximal end and an open distal end. The retainer 108 may be coupled between the needle guard extension 126 and the housing 102. In some embodiments, the retainer 108 is coupled between the needle guard body 128 and the housing 102. The retainer 108 may be a ring slideably coupled to the housing 102. The retainer 108 may be moveable about the longitudinal axis LA relative to the housing 102. The retainer 108 may extend around a circumference of the housing 102. In some embodiments, the retainer 108 extends around only a portion of the housing 102.

[0066] As shown in Fig. 16, the retainer 108 may include a lip 150 defined on the proximal end thereof. The lip 150 may be a generally rectangular member extending around a portion of the inner surface of the retainer 108. The lip 150 may be shaped and sized to be at least partially disposed in the extension recess 136. The lip 150 may be configured to engage the needle guard extension 126 and the needle guard body 128 as the retainer 108 is moved relative to the housing 102, as described in more detail below.

[0067] The retainer 108 may have a notch 154 defined on the proximal end thereof. The notch 154 may extend proximally along the longitudinal axis LA from the proximal end of the retainer 108. The notch 154 may be a rounded member. In some embodiments, the notch 154 may be a triangular or polygonal member. The notch 154 may be configured to engage the extension arm 134 when the lip 150 is disposed in the extension recess 136 to prevent the retainer 108 from rotating relative to the needle guard extension 126 in a first direction beyond a predetermined position.

[0068] As shown in Fig. 16, the retainer 108 may include an adjustment interface 156 extending radially therefrom. The adjustment interface 156 may be a knob or protrusion extending from the retainer 108. The adjustment interface 156 may be located proximate the distal end of the retainer 108. In some embodiments, the adjustment interface 156 is spaced apart from the distal end of the retainer 108. The adjustment interface 156 may be shaped and sized such that at least a portion of the adjustment interface 156 extends through the guide 124. The adjustment interface 156 may extend through the guide 124 such that a user may engage the adjustment interface 156 to move the retainer 108 relative to the housing 102. The adjustment interface 156 may engage a first end of the guide 124 when the adjustment interface 156 is rotated relative to the housing 102 in a first direction and may engage a second end of the guide 124 when the adjustment interface 156 is rotated relative to the housing 102 in a second direction. The guide 124 may restrict movement of the retainer 108 about the longitudinal axis LA relative to the housing 102.

[0069] As shown in Figs. 11 and 13, the front housing 110 may be configured to house at least the needle 104, the needle guard assembly 106, the retainer 108 and a medicament container 122. The medicament container 122 may be at least partially disposed within the housing 102. The medicament container 122 may be fixed relative to the housing 102. The medicament container 122 may contain a volume of a medicament. As used herein, the medicament may comprise drugs, biologies, solutions, gels, suspensions or other substances that may be delivered via a syringe or needle, and such terms may be used interchangeably as appearing in the specification and claims. The medicament container 122 may be a prefilled syringe. In some embodiments, the medicament container 122 may be an insertable medicament cartridge. In one embodiment, the medicament container 122 is one ofa prefilled cartridge, vial or other injectable fluid-containing vessel. The medicament container 122 has a distal portion and a proximal portion opposite the distal portion.

[0070] In one embodiment, the medicament container 122 has a maximum volume of approximately 10 mL. The autoinjector 100 may be configured to deliver the entire amount or a portion of the medicament within medicament container 122. In one embodiment, the medicament container 122 has a maximum volume selected from approximately: a) 3 mL, 3.5 mL, 4 mL, 4.5 mL, 5.5 mL, 6 mL, 6.5 mb, 7 mL, 7.5 mL, 8 m , 8.5 mb,9 mL, 9.5 mL, 10 mL, 10.5 mL, l l mL, 11.5 mL, 12 mL, 12.5 mL, 13 mL, 13.5 mL, 14 mL,14.5 mL, 15 mL, 15.5 mL, 16 mL, 16.5 mL, 17 mL, 17.5 mL, 18 mL, 18.5 mL, 19 mL,19.5 mL, 20 mL, 25 mL, 30 mL, 35 mL, 40 mL, 45 mL, and 50 mL; b) 3 mL to 5 mL, 3 mL to 10 mL, 3 mL to 15 mL, 3 mL to 20 mL, 3 mL to 25 mL, 3 mL to 30 mL, 3 mL to 35 mL, 3 mL to 40 mL, 3 mL to 45 mL, 3 mL to 50 mL, 5 mL to10 mL, 5 mL to 15 mL, 5 mL to 20 mL, 5 mL to 25 mL, 5 mL to 30 mL, 5 mL to 35 mL, 5 mL to 40 mL; 5 mL to 45 mL, 5 mL to 50 mL, 10 mL to 15 mL, 10 mL to 20 mL, 10 mL to 25 mL,10 mL to 30 mL, 10 mL to 35 mL, 10 mL to 40 mL, 10 mL to 50 mL; c) about 3 mL to about 5 mL, about 3 mL to about 10 mL, about 3 mL to about 15 mL, about 3 mL to about 20 mL, about 3 mL to about 25 mL, about 3 mL to about 30 mL, about 3 mL to about 35 mL, about 3 mL to about 40 mL, about 3 mL to about 45 mL, about 3 mL to about 50 mL, about 5 mL to about 10 mL, about 5 mL to about 15 mL, about 5 mL to about 20 mL, about 5 mL to about 25 mL, about 5 mL to about 30 mL, about 5 mL to about 35 mL, about 5 mL to about 40 mL, about 5 mL to about 45 mL, about 5 mL to about 50 mL, about 10 mL to about 15 mL, about 10 mL to about 20 mL, about 10 mL to about 25 mL, about 10 mL to about 30 mL, about 10 mL to about 35 mL, about 10 mL to about 40 mL, about 10 mL to about 50 mL; d) at least about 3 mL, at least about 3.5 mL, at least about 4 mL, at least about 4.5 mL, at least about 5.5 mL, at least about 6 mL, at least about 6.5 mL, at least about 7 mL, at least about 7.5 mL, at least about 8 mL, at least about 8.5 mL, at least about 9 mL, at least about9.5 mL, at least about 10 mL, at least about 10.5 mL, at least about 11 mL, at least about11.5 mL, at least about 12 mL, at least about 12.5 mL, at least about 13 mL, at least about13.5 mL, at least about 14 mL, at least about 14.5 mL, at least about 15 mL, at least about15.5 mL, at least about 16 mL, at least about 16.5 mL, at least about 17 mL, at least about17.5 mL, at least about 18 mL, at least about 18.5 mL, at least about 19 mL, at least about19.5 mL, at least about 20 mb, at least about 25 mL, at least about 30 mb, at least about 35 mb, at least about 40 mL, at least about 45 mL, at least about 50 mL; and e) at least 3 mL, at least 3.5 mL, at least 4 mL, at least 4.5 mL, at least 5.5 mL, at least 6 mL, at least 6.5 mL, at least 7 mL, at least 7.5 mL, at least 8 mL, at least 8.5 mL, at least 9 mL, at least 9.5 mL, at least 10 mL, at least 10.5 mL, at least 11 mL, at least 1 1.5 mL, at least 12 mL, at least 12.5 mL, at least 13 mL, at least 13.5 mL, at least 14 mL, at least 14.5 mL, at least 15 mL, at least 15.5 mL, at least 16 mL, at least 16.5 mL, at least 17 mL, at least17.5 mL, at least 18 mL, at least 18.5 mL, at least 19 mL, at least 19.5 mL, at least 20 mL, at least 25 mL, at least 30 mL, at least 35 mL, at least 40 mL, at least 45 mL, at least 50 mL.

[0071] Referring to Figs. 11 and 13, the medicament container 122 may further comprise a plunger 160 disposed therein that is moveable relative to the medicament container 102. Prior to use or triggering of the autoinjector 100, the plunger 160 may be disposed proximate the distal portion of the medicament container 122. The plunger 160 may seal the medicament in the medicament container 122. The plunger 160 may be generally cylindrical and made of a rubber material. In one embodiment, the plunger 160 is made of a plastic, butyl rubber, polyisoprene, polytetrafluorethylene, high-density polyethylene or other thermoset elastomers.

[0072] Referring to Figs. 1 1 and 13, the needle 104 may be in fluid communication with the medicament in the medicament container 122. As shown in Fig. 2, a luer plug 158 may be coupled to the distal end of the medicament container 122 prior to use of the autoinjector 100. The luer plug 158 may be removed by a user and the needle 104 may be coupled thereto. The medicament container 122 and the needle 104 may be coupled by threaded engagement. In some embodiments, the medicament container 122 and the needle 104 are coupled by snap-fit engagement or another appropriate coupling engagement. The needle 104 may be a 25 -gauge needle. The needle 104 may correspond to a size selected from: a) 15 gauge, 16 gauge, 17 gauge, 18 gauge, 19 gauge, 20 gauge, 21 gauge, 22 gauge,23 gauge, 24 gauge, 25 gauge, 26 gauge, 27 gauge, 28 gauge, 29 gauge, 30 gauge, 31 gauge, 32 gauge, 33 gauge, 34 gauge, or 35 gauge; b) 15 gauge to 17 gauge, 15 gauge to 20 gauge, 15 gauge to 22 gauge, 15 gauge to25 gauge, 15 gauge to 27 gauge, 15 gauge to 30 gauge, 15 gauge to 32 gauge, 15 gauge to35 gauge, 20 gauge to 22 gauge, 20 gauge to 25 gauge, 20 gauge to 27 gauge, 20 gauge to30 gauge, 20 gauge to 32 gauge, 20 gauge to 35 gauge, 25 gauge to 27 gauge, 25 gauge to30 gauge, 25 gauge to 32 gauge, 25 gauge to 35 gauge, 30 gauge to 32 gauge, or 30 gauge to 35 gauge; andc) at least 15 gauge, at least 16 gauge, at least 17 gauge, at least 18 gauge, at least19 gauge, at least 20 gauge, at least 21 gauge, at least 22 gauge, at least 23 gauge, at least24 gauge, at least 25 gauge, at least 26 gauge, at least 27 gauge, at least 28 gauge, at least29 gauge, at least 30 gauge, at least 31 gauge, at least 32 gauge, at least 33 gauge, at least34 gauge, or at least 35 gauge.

[0073] Flow rate of the autoinjector 100 is heavily dependent on the viscosity and volume of the medicament. However, the autoinjector 100 may deliver the full volume of the medicament at a rate of approximately 0.33 mL / sec. The autoinjector 100 may deliver 10 mL of the medicament at a rate of 0.33 mL / sec. In one embodiment, the autoinjector 100 delivers the full deliverable volume of the medicament at a rate of a) 0.5 mL / 10 sec., 0.75 mL / 10 sec., 1 mL / 10 sec., 1.25 mL / 10 sec., 1.5 mL / 10 sec., 1.75 mL / 10 sec., 2 mL / 10 sec., 2.25 mL / 10 sec., 2.5 mL / 10 sec., 2.75 mL / 10 sec., 3 mL / 10 sec., 3.25 mL / 10 sec., 3.5 mL / 10 sec., 3.75 mL / 10 sec., 4 mL / 10 sec., 4.25 mL / 10 sec.,4.5 mL / 10 sec., 4.75 mL / 10 sec., 5 mL / 10 sec.; b) at least 0.5 mL / 10 sec., at least 0.75 mL / 10 sec., at least 1 mL / 10 sec., at least1.25 mL / 10 sec., at least 1.5 mL / 10 sec., at least 1.75 mL / 10 sec., at least 2 mL / 10 sec., at least2.25 mL / 10 sec., at least 2.5 mL / 10 sec., at least 2.75 mL / 10 sec., at least 3 mL / 10 sec., at least3.25 mL / 10 sec., at least 3.5 mL / 10 sec., at least 3.75 mL / 10 sec., at least 4 mL / 10 sec., at least4.25 mL / 10 sec., at least 4.5 mL / 10 sec., at least 4.75 mL / 10 sec., at least 5 mL / 10 sec.; c) 2 mL / 30 sec., 2.5 mL / 30 sec., 3 mL / 30 sec., 3.5 mL / 30 sec., 4 mL / 30 sec.,4.5 mL / 30 sec., 5 mL / 30 sec., 5.5 mL / 30 sec., 6 mL / 30 sec., 6.5 mL / 30 sec., 7 mL / 30 sec.,7.5 mL / 30 sec., 8 mL / 30 sec., 8.5 mL / 30 sec., 9 mL / 30 sec., 9.5 mL / 30 sec., 10 mL / 30 sec.,10.5 mL / 30 sec.; and d) 4 mL / min, 5 mL / min, 6 mL / min, 7 mL / min, 8 mL / min, 9 mL / min, 10 mL / min, 11 mL / min, 12 mL / min, 13 mL / min, 14 mL / min, 15 mL / min, 16 mL / min, 17 mL / min, 18 mL / min, 19 mL / min, 20 mL / min, 21 mL / min.

[0074] The viscosity of the medicament may be between 1-20 cP. In one embodiment, the medicament may have a viscosity of: a) 1 cP, 2 cP, 3 cP, 4 cP, 5 cP, 6 cP, 7 cP, 8 cP, 9 cP, 10 cP, 11 cP, 12 cP, 13 cP, 14 cP, 15 cP, 16 cP, 17 cP, 18 cP, 19 cP, 20 cP; and b) between 1-20 cP, between 2-19 cP, between 3-18 cP, between 4-17 cP, between 5-16 cP, between 6-15 cP, between 7-14 cP, between 8-13 cP, between 9-12 cP, between 10-11 cP.

[0075] In some embodiments, the user’s experience is improved if the autoinjector 100 delivers the full volume of the medicament as fast as possible. A faster delivery may result in less pain and discomfort for the patient. The autoinjector 100 may deliver the full deliverable volume of the medicament in less than 5 seconds. In some embodiments, the autoinjector 100 may deliver the full deliverable volume of the medicament in less than 10 seconds, less than 15 seconds, less than 20 seconds, less than 25 seconds, less than 30 seconds, less than 35 seconds, less than 40 seconds, less than 45 seconds, less than 50 seconds, less than 55 seconds, less than 60 seconds, less than 70 seconds, less than 80 seconds, less than 90 seconds, less than 100 seconds, less than 1 10 seconds, or less than 120 seconds. In some embodiments, the autoinjector 100 may deliver the full volume of the medicament in between 5-120 seconds, between 10-110 seconds, between 15-100 seconds, between 20-90 seconds, between 25-80 seconds, between 30-70 seconds, between 35-60 seconds, between 40-55 seconds, or between 45-50 seconds.

[0076] As shown in Figs. 2-13, the rear housing 112 may be configured to house the trigger 162, the latch 164, the ram 166 and the energy source 168. The trigger 162 may be disposed within the housing 102 and may be coupled to the needle guard assembly 106. The trigger 162 may be moveable relative to the housing 102 along the longitudinal axis LA in response to movement of the needle guard assembly 106. As described in more detail below, engagement of the trigger 162 with the latch 164 during movement of the needle guard assembly 106 may cause the autoinjector 100 to expel the medicament from the medicament container. The trigger 162 may be a generally cylindrical member extending along the longitudinal axis LA. The trigger 162 may have a trigger body 170 and at least one trigger arm 172 extending axially from the trigger body 170.

[0077] As shown in Figs. 2-13, the trigger body 170 may have a proximal end and a distal end opposite the proximal end. Both the proximal end and the distal end of the trigger body 170 may be open and sized to receive components of the rear housing 112 therein, as described in more detail below. The trigger body 170 may include a trigger aperture 174 extending therethrough. The trigger aperture 174 may be shaped and sized to allow at least a portion of the latch 164 to extend therethrough. The trigger aperture 174 may be located proximate the distal end of the trigger body 170. In some embodiments, the trigger aperture 174 is located between the proximal end and the distal end, or proximate the distal end of the trigger body 170. The trigger aperture 174 may be a generally rectangular shape. In some embodiments, the trigger aperture 174 is a rounded shape.

[0078] As shown in Figs. 2-13, the trigger arm 172 may extend distally along the longitudinal axis LA from the trigger body 170. The trigger arm 172 may be a generally rectangular member with a curvature about the longitudinal axis LA substantially similar to that of the trigger body 170. Thetrigger arm 172 may include a first arm member 176 and a second arm member 178 defining a trigger arm slot 180 therebetween. The trigger arm slot 180 may extend from a distal end at least partially along a length of the trigger arm 172. The trigger arm slot 180 may be shaped and sized to receive the body arm protrusion 148 therein. Engagement of the trigger arm slot 180 and the body arm protrusion 148 may fix the needle guard body 128 to the trigger 162.

[0079] As shown in Figs. 2-13, the latch 164 may be disposed within the housing 102 and may be fixed relative thereto. The latch 164 may be fixed proximate the proximal end of the housing 102 in the rear housing 112. The latch 164 may be configured to engage the trigger 162 as the trigger 162 moves relative to the latch 164 in response to movement of the needle guard assembly 106 moving relative to the housing 102. The latch 164 may include a latch body 182 having a generally cylindrical shape extending along the longitudinal axis LA. The latch body 182 may be shaped and sized to fit within the trigger body 170. The trigger body 170 may be disposed between the latch body 182 and the rear housing 112 and may be moveable relative to the latch body 182 and the rear housing 112.

[0080] The latch 164 may prevent movement of the ram 166 relative to the housing 102 prior to an injection. The latch 164 may include a first latch flexible arm 184 having a first protrusion 186 extending radially inward from the first latch flexible arm 184. The first latch flexible arm 184 may be a generally rectangular member. The first protrusion 186 may be located at a proximate end of the first latch flexible arm 184 and may have a generally triangular cross section with angled surfaces facing proximally and distally. At least a portion of the first protrusion 186 is configured to be received by the ram 166 to prevent movement of the ram 166 relative to the latch 164. Proximal movement of the needle guard assembly 106 may disengage the first protrusion 186 from the ram 166 to enable movement of the ram 166 relative to the latch 164.

[0081] The latch 164 may prevent the trigger 162 from moving distally relative to the housing 102 prior to an injection. The latch 164 may include a second latch flexible arm 188 extending distally along the longitudinal axis LA and a second protrusion 190 extending radially outward from the second latch flexible arm 188. The second latch flexible arm 188 may be a generally rectangular member. The second protrusion 190 may be located at a distal end of the second latch flexible arm 188 and may have a generally triangular cross section with angled surfaces facing proximally and distally. At least a portion of the second protrusion 190 is configured to be received by the trigger 162 to prevent movement of the trigger 162 relative to the housing 102. Proximal movement of the needle guard assembly 106 may disengage the second protrusion 190 from the trigger 162 to enable movement of the trigger 162 relative to the latch 164.

[0082] During an injection, the ram 166 may be urged by the energy source 168 to move the plunger 160 through the medicament container 122 to expel the medicament through the needle 104. The ram 166 may be moveable relative to the latch 164 and the housing 102. As shown in Figs. 11 and 13, the ram 166 may include a ram body 192. The ram body 192 may be a generally cylindrical member extending along the longitudinal axis LA. The ram body 192 may have a proximal end and a distal end opposite the proximal end, the proximal end of the ram body 192 may be open and the distal end of the ram body 192 may be closed. The proximal end of the ram body 192 may be shaped and sized to receive the energy source 168 therein.

[0083] The energy source 168 may be configured to urge the ram 166 distally along the longitudinal axis LA relative to the latch 164. As shown in Figs. 11 and 13, energy source 168 may be disposed at least partially within the ram 166. A proximal end of the energy source 168 may engage the latch 164 and a distal end of the energy source 168 may engage a distal end of the ram 166. In an exemplary embodiment, energy source 168 includes a compression spring; however, other suitable energy source can be used, such as an electric pump, elastomer or compressed-gas spring, or a gas generator, or other suitable energy storage members.

[0084] The energy source 168 may be a compression spring. The energy source 168 may have a 5 mm diameter. The energy source 168 may have a 6 mm diameter. The energy source 168 may have a 7 mm diameter. The energy source 168 may have an 8 mm diameter. The energy source 168 may have a 9 mm diameter. The energy source 168 may have a 10 mm diameter. The energy source 168 may have an 11 mm diameter. The energy source 168 may have a 12 mm diameter. The energy source 168 may have a 13 mm diameter. The energy source 168 may have a 14 mm diameter. The energy source 168 may have a 15 mm diameter. The energy source 168 may have a 0.75 mm wire diameter. The energy source 168 may have a 1 mm wire diameter. The energy source 168 may have a 1.25 mm wire diameter. The energy source 168 may have a 1.5 mm wire diameter. The energy source 168 may have a 1.75 mm wire diameter. The energy source 168 may have a 2 mm wire diameter.

[0085] The energy source 168 may produce at least 8 Ibf of force, at least 9 Ibf of force, at least 10 Ibf of force, at least 11 Ibf of force, at least 12 Ibf of force, at least 13 Ibf of force, at least 14 Ibf of force, at least 15 Ibf of force, at least 16 Ibf of force, at least 17 Ibf of force, at least 18 Ibf of force, at least 19 Ibf of force, at least 20 Ibf of force, at least 21 Ibf of force, at least 22 Ibf of force, at least 23 Ibf of force, at least 24 Ibf of force, at least 25 Ibf of force, at least 26 Ibf of force, at least 27 Ibf of force, at least 28 Ibf of force, at least 29 Ibf of force, or at least 30 Ibf of force. The energy source 168 may produce between 8-30 Ibf of force, between 9-29 Ibf of force, between 10-28 Ibf of force,between 11— 27 Ibf of force, between 12-26 Ibf of force, between 13-25 Ibf of force, between 14-24 Ibf of force, between 15-23 Ibf of force, between 16-22 Ibf of force, between 17-21 Ibf of force, or between 18-20 Ibf of force.

[0086] The energy source 168 may generate up to 15 Ibf of force prior to a triggering event. The energy source 168 may generate up to 17.5 Ibf of force prior to a triggering event. The energy source 168 may generate up to 20 Ibf of force prior to a triggering event. The energy source 168 may generate up to 22.5 Ibf of force prior to a triggering event. The energy source 168 may generate up to25 Ibf of force prior to a triggering event. The energy source 168 may generate up to 27.5 Ibf of force prior to a triggering event. The energy source 168 may generate up to 30 Ibf of force prior to a triggering event.

[0087] As shown in Figs. 2-13, the retainer 108 may be moveable relative to the housing 102 from a blocking position (Figs. 2-5) where the retainer 108 retains the needle guard extension 126 relative to the housing 102 in the retracted position to an unblocking position (Figs. 6-7) where the retainer 108 allows the needle guard extension 126 to move relative to the housing 102 to the extended position. The adjustment interface 156 may be engaged by a user to move the retainer 108 relative to the housing 102 from the blocking position to the unblocked position.

[0088] As shown in Figs. 2-3, when the autoinjector 100 is in an out-of-box state, a user may be able to remove a luer plug 158 or other blocking device from the medicament container 122 to expose a port thereon. The retainer 108 may be in the blocking position and the needle guard extension 126 may be in the retracted position to enable a user to inspect the medicament container 122 while the luer plug 158 is removed. The adjustment interface 156 may be positioned proximate the first end of the guide 124 in the blocking position. A user may be able to inspect the medicament container 122 through the housing recess 120. The lip 150 may be disposed in the extension recess 136, thereby preventing the needle guard spring 130 from urging the needle guard extension 126 distally along the longitudinal axis LA.

[0089] As shown in Figs. 4-5, a user may attach a needle 104 to the medicament container 122. The retainer 108 may be in the blocking position and the needle guard extension 126 may be in the retracted position. The adjustment interface 156 may be positioned proximate the first end of the guide 124 in the blocking position. The user may inspect the connection of the needle 104 and the medicament container 122 through the housing recess 120. The housing recess 120 may be shaped and sized to allow a user’s finger to pass therethrough to couple the needle 104 to the medicament container. The needle 104 may extend past a distal end of the housing 102. When the needle 104 isattached to the medicament container 122 and the retainer 108 is in the blocking position, the needle 104 may be exposed, thereby creating a risk of needle-stick injury or damage to the needle.

[0090] As shown in Figs. 6-7, a user may rotate the retainer 108 relative to the housing 102 from the blocking position to the unblocked position. The adjustment interface 156 may be engaged by a user to move the retainer 108 relative to the housing 102 to the unblocked position. The adjustment interface 156 may be spaced apart from the first end of the guide 124 and the second end of the guide 124 in the unblocked position. The rotation of the retainer 108 from the blocking position to the unblocked position may also be relative to the needle guard extension 126 such that the lip 150 is spaced radially apart from the extension recess 136 when the retainer 108 is in the unblocked position. The disengagement of the lip 150 and the extension recess 136 may allow the needle guard spring 130 to urge the needle guard extension 126 distally relative to the needle guard body 128 and the housing 102 from the retracted position toward the extended position.

[0091] As the needle guard extension 126 is urged distally from the retracted position toward the extended position, the flexible leg 138 of the extension arm 134 may slideably engage the engagement surface 144 of the needle guard body 128. This engagement of the flexible leg 138 and the engagement surface 144 may temporarily move the flexible leg 138 from the neutral position to the flexed position until the flexible leg 138 advances distally past the engagement surface 144 into the recess 146. The recess 146 may receive at least a portion of the flexible leg 138 therein. The flexible leg 138 may return to the neutral position when the flexible leg 138 is received in the recess 146. The foot 140 may be disposed in the recess 146.

[0092] Engagement of the recess 146 and the flexible leg 138 may couple the needle guard body 128 and the needle guard extension 126 as a single needle guard assembly 106. As shown in Fig. 7, the retainer 108 may prevent proximal movement of the needle guard assembly 106 relative to the housing 102 when the retainer 108 is in the unblocked position. The needle guard assembly may be prevented from moving proximally relative to the housing by the lip 150. The lip 150 may engage the body arm knob 152 to prevent proximal movement thereof when the recess is in the unblocked position. This may prevent accidental firing of the autoinjector 100 as the needle guard extension 126 moves relative to the needle guard body 128 from the retracted position to the extended position. This may also prevent firing of the autoinjector 100 due to proximal movement of the needle guard assembly 106 when the needle guard body 128 and the needle guard extension 126 are coupled.

[0093] As shown in Figs. 8-9, the retainer 108 may be further moveable relative to the housing 102 to an active position. In the active position, the retainer 108 may allow proximal movement of the needle guard assembly 106 relative to the housing 102. The adjustmentinterface 156 may be engaged by a user to move the retainer 108 relative to the housing 102 to the active position. The adjustment interface 156 may be positioned proximate the second end of the guide 124 when the retainer 108 is in the active position. Rotation of the retainer 108 relative to the housing 102 may cause the lip 150 to be radially spaced apart from the body arm knob 152 when the retainer 108 is in the active position. Disengagement of the lip 150 and the body arm knob 152 may allow proximal movement of the needle guard assembly 106 relative to the housing 102. Movement of the needle guard assembly 106 relative to the housing 102 may trigger the autoinjector 100, as described in more detail below.

[0094] In some embodiments, movement of the retainer 108 relative to the guide 124 may be temporarily inhibited. For example, the guide 124 may have a ribbed surface or have one or more cutouts defined thereon. Engagement of the guide 124 and the retainer 108 may create friction therebetween to reduce accidental movement of the retainer 108 relative to the housing 102. A user may need to overcome the frictional engagement of the guide 124 to move the retainer 108 relative to the housing 102. The retainer 108 may be temporarily prevented from moving relative to the guide 124 when the retainer is moved relative to the housing 102 from the blocking position to the unblocked position to allow the needle guard extension 126 to move relative to the needle guard body 128 from the retracted state to the extended state. A user engaging the adjustment interface 156 may have to overcome the engagement of the retainer 108 and the guide 124 to move the retainer 108 from the unblocked position to the active position.

[0095] As shown in Figs. 10-11, the needle guard assembly 106 may be moveable proximally relative to the housing 102 to expose at least a portion of the needle 104. Proximal movement of the needle guard assembly 106 may cause the needle guard assembly 106 to engage the trigger 162 to activate the energy source 168. Proximal movement of the needle guard assembly 106 may cause the energy source 168 to move the plunger 160 distally relative to the medicament container 122 to expel the medicament therefrom through the needle 104.

[0096] As shown in Figs. 12-13, the autoinjector 100 may be a single-use autoinjector. The needle guard assembly 106 may be urged back toward an extended state by the needle guard spring 130 following delivery of the medicament and removal of the needle 104 from the injection site. The needle guard spring 130 may urge the needle guard assembly 106 and the trigger 162 distally such that at least one of the first latch flexible arm 184 and the second latch flexible arm 188 engage the trigger aperture 174 to prevent the trigger from moving proximally. The autoinjector 100 may be discarded after use. In some embodiments, the autoinjector 100 can be sanitized and reused following an injection.

[0097] A method of delivering a medicament to a subject may be disclosed herein. The method may include providing an autoinjector 100 to a user. The autoinjector 100 may include a housing 102 having a medicament container 122 containing a volume of a medicament disposed at least partially therein. The medicament container 122 may have a luer plug 158 fixed to a distal end thereof that may be removed by a user. The user may couple a needle 104 to the distal end of the medicament container 122 to fluidly couple the needle 104 and the medicament.

[0098] The user may rotate a retainer 108 relative to the housing 102 from a blocking position to an unblocked position by engaging an adjustment interface 156 extending at least partially therefrom through the housing 102. Rotation of the retainer 108 relative to the housing 102 to the unblocked position may allow a needle guard spring 130 to urge a needle guard extension 126 from a retracted position to an extended position relative to the housing 102. The needle guard extension 126 may extend distally past the needle 104 when the needle guard extension is in the extended position. The needle guard extension 126 may couple to a needle guard body 128, thereby forming a single needle guard assembly 106. The needle guard assembly 106 may be prevented from moving proximally relative to the housing 102 by the retainer 108 in the unblocked position.

[0099] The user may then rotate the retainer 108 relative to the housing 102 from the unblocked position to an active position by engaging an adjustment interface 156 extending at least partially therefrom through the housing 102. Rotation of the retainer 108 relative to the housing 102 to the active position may allow the needle guard assembly 106 to move proximally relative to the housing 102. The user may press the needle guard assembly 106 against an injection site on a subject to activate the autoinjector 100 and expel the medicament from the needle into the injection site. The user may remove the needle 104 from the injection site and dispose of the autoinjector 100.

[0100] Referring to Figs. 17-29, there is shown a second embodiment of the autoinjector, generally designated 200. The autoinjector 200 is similar to the first embodiment of the 100 except that the needle guard extension 226 may be configured to rotate about the longitudinal axis LA in response to rotation of the retainer 208 about the longitudinal axis LA.

[0101] Referring to Fig. 17, a front housing 210 of autoinjector 200 is shown. Front housing 210 may include a guide 224, a window 218 and a housing recess 220 defined thereon. The front housing 210 may be configured to house at least a needle guard assembly 206 within the retainer 208. The needle guard assembly 206 may comprise the needle guard extension 226 disposed at least partially within the housing 202 and a needle guard body 228 disposed within the housing 202. The needle guard extension 226 may be moveable relative to the housing 202 from a retracted position where a needle 204 extends distally past the needle guard extension 226 and an extended positionwhere the needle guard extension 226 extends distally past the needle 204. The needle guard extension 226 may be moveable relative to the needle guard body 228 from the retracted position to the extended position and may be configured to couple to the needle guard body 228 in the extended position.

[0102] The needle guard assembly 206 may include a needle guard spring 230 disposed between the needle guard extension 226 and the needle guard body 228. The needle guard spring 230 may be configured to move the needle guard extension 226 relative to the needle guard body 228 from the retracted position to the extended position. The needle guard spring 230 may engage a distal end of the needle guard body 228 and a distal end of the needle guard extension 226. The needle guard spring 230 may be prevented by the retainer 208 from moving the needle guard extension 226 relative to the needle guard body 228 from the retracted position to the extended position.

[0103] As shown in Fig. 27, the needle guard extension 226 may be a generally cylindrical member extending along the longitudinal axis LA between a proximal end and a distal end. The needle guard extension 226 may include an extension body 232 and at least one extension arm 234 extending proximally therefrom. The extension body 232 may be a cylindrical member with an open distal end that is shaped and sized to receive at least a portion of the needle guard body 228 therein when the needle guard extension 226 is in the retracted position. The extension body 232 may have an open distal end that is shaped and sized to allow the needle 204 to pass therethrough.

[0104] The extension body 232 may have a spine 233 defined thereon. The spine 233 may extend generally along the longitudinal axis LA and may protrude radially outward from the extension body 232. The spine 233 may extend a length of the extension body 232. In some embodiments, the spine 233 extends only a portion of the length of the extension body 232. The spine may be shaped and sized to be received by the retainer 208 to prevent rotation of the needle guard extension 226 relative to the retainer 208, as described in more detail below.

[0105] As shown in Fig. 27, the needle guard extension 226 may have two extension arms 234. In some embodiments, the needle guard extension 226 has one extension arm 234. The extension arm 234 may be a generally rectangular member extending proximally from a proximal end of the extension body 232. The extension arm 234 may have a curvature about the longitudinal axis LA similar to a curvature of the extension body 232. The extension arm 234 may be able to flex relative to the extension body 232 such that the proximal end of the extension arm 234 may be angled relative to the longitudinal axis LA in response to a force acting thereon. The extension arm 234 may be comprised of an elastic material allowing it to flex and deflect back to its original shape and position when the force is removed.

[0106] The extension arm 234 may include an extension recess 236 defined thereon. The extension recess 236 may be a generally rectangular recess. In some embodiments, the extension recess 236 is a rounded or polygonal recess. The extension recess 236 may extend through the extension arm 234 and may extend across a portion of the width of the extension arm 234. The extension recess 236 may be defined proximate the proximal end of the extension arm 234. In some embodiments, the extension recess 236 is spaced apart from the proximal end of the extension arm 234.

[0107] As shown in Fig. 27, the needle guard extension 226 may have a catch 235 extending therefrom. The catch 235 may extend axially from the extension arm 234. The catch 235 may be configured to engage the needle guard body 228 to prevent distal movement of the needle guard extension 226 relative to the needle guard body 228. When the needle guard extension 226 is rotated about the longitudinal axis LA relative to the needle guard body 228 in response to movement of the retainer 208, the catch 235 may be configured to disengage the needle guard body 228 to allow distal movement of the needle guard extension 226 relative to the needle guard body 228. The catch 235 may have a catch knob 237 extending therefrom. The catch knob 237 may extend distally from an end of the catch 235 and may create a frictional engagement between the catch 235 and the needle guard body 228 to prevent unintentional rotation of the needle guard extension 226 relative to the needle guard body 228. A user may overcome the frictional engagement between the catch 235 and the needle guard body 228 by applying a sufficient force to the retainer 208.

[0108] As shown in Fig. 27, the needle guard extension 226 may have a flexible leg 238 extending distally therefrom. The flexible leg 238 may be configured to engage the needle guard body 228 as the needle guard extension 226 is moved from the retracted position to the extended position. The needle guard extension 226 may have one flexible leg 238 extending distally therefrom. In some embodiments, the needle guard extension 226 has two flexible legs 238 extending distally therefrom. The flexible leg 238 may extend proximally from the proximal end of the extension arm 234. The flexible leg 238 may include a foot 240 disposed thereon. The foot 240 may extend from the flexible leg 238 radially inward. In some embodiments, the flexible leg 138 extends radially outward.

[0109] The flexible leg 238 may be moveable between a neutral position where the flexible leg 238 extends substantially along the longitudinal axis LA and a flexed position where the flexible leg 238 flexes radially outward from the longitudinal axis LA. In some embodiments, the flexible leg 238 flexes inward about the longitudinal axis LA relative to the extension arm 234 in the flexed position. The foot 240 may have angled surfaces to urge the flexible leg 238 from the neutral positionto the flexed position in response to engagement of the foot 240 and the needle guard body 228 as the needle guard extension 226 is moved from the retracted position to the extended position.

[0110] As shown in Fig. 28, the needle guard body 228 may be a generally cylindrical member extending along the longitudinal axis LA between a proximal end and a distal end. The needle guard body 228 may be disposed within the housing. The needle guard body 228 may include at least one body arm 242 extending between the proximal end and the distal end of the needle guard body 228. The needle guard body 228 may be shaped and sized to be disposed within the needle guard extension 226. The needle guard body 228 may be open at both the distal end and proximal end to allow other components of the autoinjector 200 to be disposed therein (e.g., the medicament container 222).

[0111] The needle guard body 228 may have two body arms 242 defined therein. The body arm 242 may be a generally rectangular member extending distally from the proximal end of the needle guard body 228 and proximally from the distal end of the needle guard body 228. The body arm 242 may have a curvature about the longitudinal axis LA similar to a curvature of the needle guard body 228.

[0112] As shown in Fig. 28, the body arm 242 may have a body arm protrusion 248 defined thereon. The body arm protrusion 248 may be a generally cubical member extending radially from the body arm 242. The body arm protrusion 248 may be shaped and sized to be received by another component of the autoinjector 200 (trigger 262) to couple the needle guard assembly 106 thereto. The body arm 242 may have a blocking member 252 defined thereon. The blocking member 252 may be a generally cubical member extending radially from the body arm 242.

[0113] As shown in Fig. 28, the needle guard body 228 may have a shoulder 245 defined thereon. The shoulder 245 may be located proximate the proximal end of the needle guard body 228 and may be configured to engage the flexible leg 238 of the needle guard extension 226 when the retainer 208 is in the blocking position. An arm aperture 247 may be defined by the shoulder 245 on a distal end and may extend through the body arm 242. The arm aperture 247 may allow the flexible leg 238 to remain in the neutral position when the retainer 208 is in the blocking position. The foot 240 of the flexible leg 238 may extend through the arm aperture 247 and may slide along the shoulder 245 as the retainer 208 is moved relative to the housing 202.

[0114] As shown in Fig. 28, the needle guard body 228 may have an engagement surface 244 defined thereon. The engagement surface 244 may be defined on the body arm 242. The engagement surface 244 may be angled such that the engagement surface 244 may urge another component (flexible leg 238) radially outward as the component slides from a proximal end toward a distal endof the engagement surface. The needle guard body 228 may have a recess 246 defined thereon. The recess 246 may be located proximate the engagement surface 244. The recess 246 may be defined on one side by the distal end of the engagement surface 244. The recess 246 may be shaped and sized to receive at least a portion of the flexible leg 238 therein when the needle guard extension 226 is moved relative to the needle guard body 228 from the retracted position to the extended position by the needle guard spring 230. The recess 246 may receive the foot 240 of the flexible leg 238 therein.

[0115] As shown in Fig. 28, the body arm 242 may include an extension recess 249 defined thereon. The extension recess 249 may be a generally rectangular recess. In some embodiments, the extension recess 249 is a rounded or polygonal recess. The extension recess 249 may be defined on an outer surface of the body arm 242 and may extend across a portion of the width of the body arm 242. In some embodiments, the extension recess 249 extends across the width of the body arm 242. In some embodiments, the extension recess 249 is defined on an inner surface of the body arm 242.

[0116] As shown in Fig. 29, the retainer 208 may be a generally cylindrical member extending along the longitudinal axis LA between a proximal end and a distal end. The retainer 208 may have an open proximal end and an open distal end. The retainer 208 may be coupled between the needle guard extension 226 and the housing 202. In some embodiments, the retainer 208 is coupled between the needle guard body 228 and the housing 202. The retainer 208 may be a ring rotatably coupled to the housing 202. The retainer 208 may be moveable about the longitudinal axis LA relative to the housing 202. The retainer 208 may extend around a circumference of the housing 202. In some embodiments, the retainer 208 extends around only a portion of the housing 202.

[0117] As shown in Fig. 29, the retainer 208 may include a lip 250 defined on the proximal end thereof. The lip 250 may be a generally rectangular member extending around a portion of the inner surface of the retainer 208. The lip 250 may be shaped and sized to be at least partially disposed in the extension recess 249. The lip 250 may be configured to slideably engage the extension recess 249 as the retainer 208 is moved relative to the housing 202. The retainer 208 may have a retainer knob 257 defined thereon. The retainer knob 257 may be a generally cubical member extending distally along the longitudinal axis LA from the distal end of the retainer 208.

[0118] As shown in Fig. 29, the retainer 208 may include a slot 251 defined therein. The slot 251 may be defined on an inner surface of the retainer 208 and may be shaped and sized to receive the spine 233 of the needle guard extension 226 therein. The slot 251 may be defined along a length of the retainer 208. In some embodiments, the slot 251 is defined along only a portion of the retainer. Engagement of the slot 251 and the spine 233 may prevent rotation of the retainer 208 relative to theneedle guard extension 226. The spine 233 may be slideable relative to the slot 251 along the longitudinal axis LA.

[0119] As shown in Figs. 17-26, the retainer 208 may be moveable relative to the housing 202 from a blocking position (Figs. 18-21) where the retainer 208 retains the needle guard extension 226 relative to the housing 202 in the retracted position to an unblocked position (Figs. 22-23) where the retainer 208 allows the needle guard extension 226 to move relative to the housing 202 to the extended position. The adjustment interface 256 may be engaged by a user to move the retainer 208 relative to the housing 202 from the blocking position to the unblocked position.

[0120] As shown in Figs. 18-19, in an out-of-box state, a luer plug 258 may be coupled to the distal end of the medicament container 222. A user may be able to remove the luer plug 258 or other blocking device from the medicament container 222 to expose a port thereon. The retainer 208 may be in the blocking position and the needle guard extension 226 may be in the retracted position to enable a user to inspect the medicament container 222 while the luer plug 258 is removed. The adjustment interface 256 may be positioned proximate the first end of the guide 224 in the blocking position. A user may be able to inspect the medicament container 222 through the housing recess 220. The lip 250 may be disposed in the extension recess 249, thereby preventing the needle guard spring 230 from urging the needle guard extension 226 distally along the longitudinal axis LA.

[0121] As shown in Figs. 20-21, a user may attach a needle 204 to the medicament container 222. The retainer 208 may be in the blocking position and the needle guard extension 226 may be in the retracted position. The adjustment interface 256 may be positioned proximate the first end of the guide 224 in the blocking position. The lip 250 may be disposed in the extension recess 249, thereby preventing the needle guard spring 230 from urging the needle guard extension 226 distally along the longitudinal axis LA. The user may inspect the connection of the needle 204 and the medicament container 222 through the housing recess 220. The housing recess 220 may be shaped and sized to allow a user’s finger to pass therethrough to couple the needle 204 to the medicament container. The needle 204 may extend past a distal end of the housing 202 when coupled to the medicament container 222. When the needle 204 is attached to the medicament container 222 and the retainer 208 is in the blocking position, the needle 204 may be exposed, thereby creating a risk of needle-stick injury or damage to the needle.

[0122] As shown in Figs. 22-23, a user may rotate the retainer 208 relative to the housing 202 from the blocking position to the unblocked position. The adjustment interface 256 may be engaged by a user to move the retainer 208 relative to the housing 202 to the unblocked position. The adjustment interface 256 may be spaced apart from the first end of the guide 224 and the second endof the guide 224 in the unblocked position. The rotation of the retainer 208 from the blocking position to the unblocked position may also rotate the needle guard extension 126 relative to the needle guard body 228 due to the engagement of the spine 233 and the slot 251 .

[0123] The needle guard extension 226 may be rotatable relative to the housing 202 about the longitudinal axis LA between a locked position where the needle guard extension 226 is prevented from moving relative to the housing 202 and an unlocked position where the needle guard extension 226 is allowed to move relative to the housing 202. The flexible leg 238 and the recess 246 may be aligned along the longitudinal axis A in the unlocked position. The flexible leg 238 and the recess 246 may not be aligned along the longitudinal axis LA in the locked position.

[0124] As noted above, the retainer 208 may be rotationally coupled to the needle guard extension 226. The retainer 208 may be configured to move the needle guard extension 226 relative to the housing 202 about the longitudinal axis LA from the locked position to the unlocked position. Rotation of the needle guard extension 226 relative to the housing 202 from the locked position to the unlocked position may disengage the catch 235 from the blocking member 252, thereby allowing proximal movement of the needle guard extension 226 relative to the housing 202 and the needle guard body 228 from the retracted position to the extended position. The lip 150 may be disposed in the extension recess 249 when the retainer 208 is in the unblocked position, thereby preventing proximal movement of the needle guard body 228 relative to the housing 202.

[0125] As the needle guard extension 226 is urged distally from the retracted position toward the extended position, the flexible leg 238 of the extension arm 234 may slideably engage the engagement surface 244 of the needle guard body 228. This engagement of the flexible leg 238 and the engagement surface 244 may temporarily move the flexible leg 238 from the neutral position to the flexed position until the flexible leg 238 advances distally past the engagement surface 244 into the recess 246. The recess 246 may receive at least a portion of the flexible leg 238 therein. The flexible leg 238 may return to the neutral position when the flexible leg 238 is received in the recess 246. The foot 140 may be disposed in the recess 246.

[0126] As shown in Figs. 22-23, the spine 233 may slide relative to the slot 251 as the needle guard extension 226 is urged distally from the retracted position toward the extended position. The spine 233 may be positioned distally of the slot 251 when the needle guard extension 226 is in the extended position. The retainer 208 may be rotatable relative to the needle guard extension 226 when the needle guard extension 226 is in the extended position.

[0127] Engagement of the recess 246 and the flexible leg 238 may couple the needle guard body 228 and the needle guard extension 226 as a single needle guard assembly 206. As shown inFig. 23, the retainer 208 may prevent proximal movement of the needle guard assembly 206 relative to the housing 202 when the retainer 208 is in the unblocked position. The needle guard assembly may be prevented from moving proximally relative to the housing by engagement of the lip 250 and the extension recess 249. This may prevent accidental firing of the autoinjector 200 as the needle guard extension 226 moves relative to the needle guard body 228 from the retracted position to the extended position. This may also prevent accidental firing of the autoinjector 200 due to proximal movement of the needle guard assembly 206 when the needle guard body 228 and the needle guard extension 226 are coupled.

[0128] As shown in Figs. 24-25, the retainer 208 may be further moveable relative to the housing 202 to an active position. In the active position, the retainer 208 may allow proximal movement of the needle guard assembly 206 relative to the housing 202. The adjustment interface 256 may be engaged by a user to move the retainer 208 relative to the housing 202 to the active position. The adjustment interface 256 may be positioned proximate the second end of the guide 224 when the retainer 208 is in the active position. Rotation of the retainer 208 relative to the housing 202 may cause the lip 250 to be radially spaced apart from the extension recess 249 when the retainer 208 is in the active position. Disengagement of the lip 250 and the extension recess 249 may allow proximal movement of the needle guard assembly 206 relative to the housing 202. Movement of the needle guard assembly 206 relative to the housing 202 may trigger the autoinjector 200, as described in more detail below.

[0129] As shown in Fig. 26, the needle guard assembly 206 may be moveable proximally relative to the housing 202 to expose at least a portion of the needle 204. Proximal movement of the needle guard assembly 206 may cause the needle guard assembly 206 to engage the trigger 262 to activate the energy source 268. Proximal movement of the needle guard assembly 206 may cause the energy source 270 to move the plunger 260 distally relative to the medicament container 222 to expel the medicament therefrom through the needle 204.

[0130] A method of delivering a medicament to a subject may be disclosed herein. The method may include providing an autoinjector 200 to a user. The autoinjector 200 may include a housing 202 having a medicament container 222 containing a volume of a medicament disposed at least partially therein. The medicament container 222 may have a luer plug 258 fixed to a distal end thereof that may be removed by a user. The user may couple a needle 204 to the distal end of the medicament container 222 to fluidly couple the needle 104 and the medicament.

[0131] The user may rotate a retainer 208 relative to the housing 202 from a blocking to an unblocked position by engaging an adjustment interface 256 extending at least partially through thehousing 202 therefrom. Rotation of the retainer 208 relative to the housing 202 to the unblocked position may allow a needle guard spring 230 to urge a needle guard extension 226 from a retracted position to an extended position relative to the housing 202. The needle guard extension 226 may advance distally past the needle 204 when the needle guard extension is in the extended position. The needle guard extension 226 may couple to a needle guard body 228, thereby forming a single needle guard assembly 206. The needle guard assembly 206 may be prevented from moving proximally relative to the housing 202 by the retainer 208 in the unblocked position.

[0132] The user may then rotate the retainer 208 relative to the housing 202 from the unblocked position to an active position by engaging an adjustment interface 256 extending at least partially through the housing 202 therefrom. Rotation of the retainer 208 relative to the housing 202 to the active position may allow the needle guard assembly 206 to move proximally relative to the housing 202. The user may press the needle guard assembly 206 against an injection site on a subject to activate the autoinjector 200 and expel the medicament from the needle into the injection site. The user may remove the needle 204 from the injection site and dispose of the autoinjector 200.

[0133] The term “about” or “approximately” is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrecited number may be a number which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number. It should be appreciated that all numerical values and ranges disclosed herein are approximate values and ranges, whether “about” is used in conjunction therewith. It should also be appreciated that the term “about,” as used herein in conjunction with a numeral, refers to avalue that may be ±0.01% (inclusive), ±0.1% (inclusive), ±0.5% (inclusive), ±1% (inclusive) of that numeral, ±2% (inclusive) of that numeral, ±3% (inclusive) of that numeral, ±5% (inclusive) of that numeral, ±10% (inclusive) of that numeral, or ±15% (inclusive) of that numeral. It should further be appreciated that when a numerical range is disclosed herein, any numerical value falling within the range is also specifically disclosed.

[0134] It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments shown and described above without departing from the broad inventive concepts thereof. It is to be understood that the embodiments and claims disclosed herein are not limited in their application to the details of construction and arrangement of the components set forth in the description and illustrated in the drawings. Rather, the description and the drawings provide examples of the embodiments envisioned. The embodiments and claims disclosed herein are further capable of other embodiments and of being practiced and carried out in various ways.

[0135] Specific features of the exemplary embodiments may or may not be part of the claimed invention and various features of the disclosed embodiments may be combined. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. Finally, unless specifically set forth herein, a disclosed or claimed method should not be limited to the performance of steps in the order written, and one skilled in the art can readily appreciate that the steps may be performed in any practical order.

Claims

CLAIMSWhat is claimed is:

1. An autoinjector comprising: a housing extending along a longitudinal axis having a proximal end and a distal end; a needle extending at least partially from the distal end of the housing; a needle guard assembly coupled to the housing having a needle guard extension moveable relative to the housing distally along the longitudinal axis from a retracted position where the needle extends distally past the needle guard extension and an extended position where the needle guard extension extends distally past the needle; and a retainer coupled between the needle guard extension and the housing retaining the needle guard extension relative to the housing in a blocking position and moveable relative to the housing to an unblocked position to allow the needle guard extension to move relative to the housing to the extended position.

2. The autoinjector of claim 1, further comprising: a needle guard body disposed within the housing having an engagement surface defined thereon, wherein the needle guard extension includes a flexible leg that slideably engages the engagement surface when the needle guard extension is moved distally from the retracted position to the extended position.

3. The autoinjector of claim 2, wherein the flexible leg is moveable between a neutral position where the flexible leg extends substantially along the longitudinal axis and a flexed position where the flexible leg flexes radially outward from the longitudinal axis, wherein the engagement surface temporarily moves the flexible leg from the neutral position to the flexed position when the needle guard extension is moved distally from the retracted position to the extended position.

4. The autoinjector of claim 3, wherein the needle guard body further comprises: a recess defined thereon proximate the engagement surface,wherein the recess is configured to receive at least a portion of the flexible leg therein when the flexible leg advances distally past the engagement surface.

5. The autoinjector of claim 4, wherein engagement of the recess and the flexible leg couples the needle guard body and the needle guard extension.

6. The autoinjector of claim 2, further comprising: a needle guard spring disposed between the needle guard extension and the needle guard body configured to move the needle guard extension from the retracted position to the extended position.

7. The autoinjector of claim 2, wherein the retainer prevents proximal movement of the needle guard assembly relative to the housing when the retainer is in the unblocked position.

8. The autoinjector of claim 7, wherein the retainer is further moveable relative to the housing to an active position where the retainer allows proximal movement of the needle guard assembly relative to the housing.

9. The autoinjector of claim 8, wherein the retainer is moveable relative to the housing by a user.

10. The autoinjector of claim 8, wherein the needle guard assembly is moveable proximally relative to the housing to expose at least a portion of the needle.

11. The autoinjector of claim 10, further comprising: a trigger disposed within the housing; a latch disposed within the housing, the latch configured to engage the trigger; a ram moveable relative to the latch; and an energy source configured to urge the ram distally relative to the latch along the longitudinal axis, wherein proximal movement of the needle guard assembly causes the needle guard assembly to engage the trigger to activate the energy source.

12. The autoinjector of claim 8, wherein the retainer further comprises: an adjustment interface extending radially therefrom, wherein the adjustment interface is engaged by a user to move the retainer relative to the housing from the blocking position to the unblocked position to the active position.

13. The autoinjector of claim 12, wherein the housing includes a guide extending therethrough, and wherein the adjustment interface extends through the guide.

14. The autoinjector of claim 13, wherein the guide engages the adjustment interface at a first end and a second end thereof to restrict movement of the retainer about the longitudinal axis relative to the housing.

15. The autoinjector of claim 14, wherein the adjustment interface is positioned proximate the first end of the guide when the retainer is in the blocking position and is positioned proximate the second end of the guide when the retainer is in the active position.

16. The autoinjector of claim 4, wherein the needle guard extension is rotatable relative to the housing about the longitudinal axis between a locked position where the needle guard extension is prevented from moving relative to the housing and an unlocked position where the needle guard extension is allowed to move relative to the housing, and wherein the retainer is rotationally coupled to the needle guard extension and configured to move the needle guard extension relative to the housing about the longitudinal axis from the locked position to the unlocked position.

17. The autoinjector of claim 17, wherein the needle guard body includes a blocking member configured to engage the needle guard extension to prevent distal movement of the needle guard extension, and wherein rotation of the needle guard extension relative to the housing about the longitudinal axis from the locked position to the unlocked position disengages the needle guard extension from the blocking member of the needle guard body allowing the needle guard extension to move relative to the housing from the retracted position to the extended position.

18. The autoinjector of claim 17, wherein the flexible leg and the recess are aligned along the longitudinal axis in the unlocked position and are not aligned along the longitudinal axis in the locked position.

19. The autoinjector of claim 1, further comprising: a medicament container disposed within the housing and containing a medicament, wherein the needle is fluidly coupled to the medicament container.

20. An autoinjector comprising: a housing extending along a longitudinal axis having a proximal end and a distal end; a medicament container disposed within the housing containing a volume of a medicament; a needle fluidly coupled to the medicament container and extending at least partially from the distal end of the housing; a needle guard assembly coupled to the housing having a needle guard extension moveable relative to the housing distally along the longitudinal axis from a retracted position where the needle extends distally past the needle guard extension and an extended position where the needle guard extension extends distally past the needle, a needle guard body disposed within the housing having an engagement surface defined thereon, and a needle guard spring disposed between the needle guard extension and the needle guard body configured to move the needle guard extension from the retracted position to the extended position; and a retainer coupled between the needle guard extension and the housing retaining the needle guard extension relative to the housing in a blocking position and moveable relative to the housing to an unblocked position to allow the needle guard to move to the extended position, wherein the needle guard extension includes a flexible leg that slideably engages the engagement surface when the needle guard extension is moved distally from the retracted position to the extended position, and wherein the retainer prevents proximal movement of the needle guard assembly relative to the housing when the retainer is in the unblocked position.

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