Needle adapter and assembly for forming an injection device for administering a fluid to a subject - Patent Application 20070122997

Abstract

A needle adapter for forming an injection device for administering a fluid to a subject is disclosed. Also disclosed is an assembly for forming an injection device for administering a fluid to a subject, the assembly including a needle adapter body. Methods for assembling the needle adapter and assembly are further disclosed, as are methods of administering a fluid to a subject using them and kits and injection devices including them.

Description

[Technical Field]

[0001] The present invention relates to needle adapters and assemblies for forming injection devices for administering fluids to a subject. The present invention also relates to methods for assembling the needle adapters and assemblies, methods for using them to administer fluids to a subject, and kits and injection devices including them. [Background technology]

[0002] A wide variety of injection devices are known in the art, the most well-known of which is the classic plastic medical syringe fitted with a detachable stainless steel needle. Such syringes are used to deliver active agents, such as drugs and vaccines, via various administration routes requiring different injection depths, such as intradermal (ID), intravenous (IV), subcutaneous (SC), or intramuscular (IM) injections. While classic plastic medical syringes are relatively inexpensive to manufacture due to their simple mechanical structure, they lack any built-in features to assist in controlled penetration of the skin to a predetermined depth. Therefore, the correct use of a classic syringe for the above-mentioned administration routes relies on the skill of the individual administering the active agent.

[0003] Morbidity and mortality due to infectious diseases have been dramatically reduced by vaccination, which is the most cost-effective public health measure for preventing the spread of disease (Lambert et al., Can successful vaccines teach us how to induce efficient protective immune responses? Nature Medicine. 2005;11:S54-S62). The three main routes of vaccine administration include ID injection, SC injection, and IM injection. Interestingly, most vaccines are given via IM injection, even though muscle is not a highly immunogenic organ (Hutin et al., Use of injections in healthcare settings worldwide, 2000: literature review and regional estimates. British Medical Journal. 2003;327:1075-1078; Hohlfed and Engel, The immunobiology of muscle. Immunology Today. 1994;15:269-274). In contrast, the skin is a much more attractive site for vaccination due to the large number of resident dendritic cells and efficient drainage to lymph nodes (Debenedictis et al., Immune functions of the skin. Clinics in Dermatology. 2001;19:573-585; Kupper and Fuhlbrigge, Immune surveillance in the skin: mechanisms and clinical consequences. Nature Reviews Immunology. 2004;4:211-222), and as a result, lower doses of antigen can elicit an immune response equivalent to a standard dose.Antigen transport studies have shown that ID vaccination results in more efficient transfer of antigens to lymph nodes than traditional IM delivery (Steinman and Branchereau, Taking dendritic cells into medicine. Nature. 2007;449:419-426; Valladeau and Saeland, Cutaneous dendritic cells. Seminars in Immunology. 2005;17:273-283; Sugita et al., Innate immunity mediated by epidermal keratinocytes promotes acquired immunity involving Langerhans cells and T cells in the skin. Clinical and Experimental Immunology. 2007;147:176-183). However, ID injection requires specialized training, and even with training, skin targeting is not reliably achieved, preventing widespread adoption of cutaneous vaccination (Flynn et al., Influence of needle gauge in Mantoux skin testing. Chest. 1994;106:1463-1465). Today, most ID injections are delivered by specially trained personnel using a conventional hypodermic needle via the Mantoux technique. The needle must be inserted into the skin at a 5-15 degree angle. The difficulties associated with delivering this injection into the skin have historically limited its use, even though a fraction of the dose of some vaccines is effective when injected into the skin.

[0004] As the primary interface between the body and the environment, the skin provides the first line of defense against a wide range of microbial pathogens (Debenedictis et al., Immune functions of the skin. Clinics in Dermatology. 2001;19:573-585; Kupper and Fuhlbrigge, Immune surveillance in the skin: mechanisms and clinical consequences. Nature Reviews Immunology. 2004;4:211-222). Although skin-targeted immunization has been available for decades, its application beyond a few vaccines has been hindered by the lack of simple and reliable cutaneous vaccination techniques. An alternative to ID injection is ID microinjection. Microneedle cutaneous vaccination has the potential to improve both the immunology and logistics of vaccination. Compared to IM injection, cutaneous vaccination with microneedles eliminates or reduces pain and anxiety experienced by patients, eliminates or reduces the risk of needlestick injury, and allows for increased vaccination coverage, as cutaneous vaccines can be administered by minimally trained medical professionals or by the patient themselves.

[0005] The need for safe, economical, and efficient vaccine administration, and increasing mechanistic knowledge of the immune response elicited by targeting the ID layer of the skin, have all driven the engineering of novel delivery devices for ID injection (Wang et al., Precise microinjection into skin using hollow microneedles. 2006;126:1080-1087; Kim and Prausnitz, Enabling skin vaccination using new delivery technologies. Drug Delivery and Translational Research. 2011;1(1):7-12). Specifically, these advanced delivery technologies use microneedles that are inserted 1.5 mm perpendicularly into the skin and inject approximately 100-200 μL of liquid vaccine into the skin layer. There is promising clinical data with several vaccines that highlight the potential for reduced-dose immunization via this ID route (Zehrung et al., Intradermal delivery for vaccine dose sparing: overview of current issues. Vaccine. 2013;31(34):3392-3395). ID injection has the potential to increase vaccine efficacy in certain populations and may help increase vaccine access, reduce costs, and ease the logistical burden of immunization programs, especially in low-resource settings.

[0006] New devices for easier, more reliable ID delivery are being developed that may serve as alternatives to the Mantoux technique and help facilitate the implementation of dose-retaining ID vaccination strategies. The range of new devices for ID delivery includes traditional needles and syringes, microneedles, microneedles that control the depth and angle of needle penetration, and adapters for ID liquid jet injectors (Zehrung et al., Intradermal delivery for vaccine dose sparing: overview of current issues. Vaccine. 2013;31(34):3392-3395). Most of these devices are currently available for research purposes only.

[0007] A highly sophisticated injection device is described in WO 2013 / 156524(A1). This injection device includes a foot that is placed on the skin, a double-ended movable needle, and a reservoir or container containing the liquid to be administered. This device has a highly sophisticated mechanism to ensure a specific sequence of events. First, the device must be unlocked. Then, one of the first needle ends enters the reservoir. The reservoir and needle then move inside the device, and the second needle end penetrates the skin. In other words, the dual-direction needle enters a pre-filled reservoir on one side and penetrates the skin on the other side. The reservoir is then emptied by depressing the plunger, and finally, the needle is retracted. This device is ideal for ID injections.

[0008] Another highly advanced assembly for forming an injection device is described in WO 2017 / 168015 (A1). The assembly includes a foot for placement on the skin and a body containing at least one needle, the body movably attached to the foot to allow the needle to move toward the skin. The needle extends outward from the second contact surface a predetermined distance to limit the needle's penetration depth. The assembly further includes first friction means for preventing movement of the body relative to the foot to cause a sudden acceleration, and second friction means for creating kinetic friction as the needle moves toward the skin to keep the skin stretched. While this assembly is particularly suitable for ID injections, in certain embodiments, the assembly can also be used for IV, SC, or IM injections.

[0009] There is a need for new injection devices, particularly those suitable for ID injection.

[0010] This background information is provided for the purpose of providing known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should it be construed, that any of the preceding information constitutes prior art against the present invention. Summary of the Invention

[0011] In one aspect, a needle adapter for forming an injection device for administering a fluid to a subject is provided, the needle adapter including a housing formed from a first housing portion and a second housing portion, the housing having a proximal end and a distal end, and a needle unit fixedly mounted within the housing. The needle unit includes a needle shaft including a first end for piercing the skin of the subject and a second end connected to a needle hub. The needle hub includes a distal end connected to the second end of the needle shaft and a proximal end including a pair of radially extending, diametrically opposed flanges. Each of the first and second housing portions includes at least two articulating transverse walls or protrusions extending from its inner surface, the at least two articulating transverse walls or protrusions forming a gap therebetween for receiving at least a portion of one or both of the pair of radially extending, diametrically opposed flanges of the needle unit for fixedly mounting the needle unit within the housing. The proximal end of the housing, together with at least two articulating transverse walls or protrusions on each of the first and second housing portions, defines a channel for receiving the syringe tip for engagement with the needle hub. The distal end of the housing includes a first contact surface adapted to be placed on the skin of a subject and a second contact surface, and the first end of the needle shaft extends outward from the second contact surface a predetermined distance to limit the penetration depth of the needle shaft.

[0012] In another aspect, an assembly for forming an injection device for administering a fluid to a subject is provided, the assembly including a foot including a first contact surface adapted to be placed on the skin of the subject, the foot having a tubular shape for receiving a needle adapter body. The needle adapter body includes a housing formed from a first housing portion and a second housing portion, the housing having a proximal end and a distal end, and a needle unit fixedly mounted within the housing. The needle unit includes a needle shaft including a first end for piercing the skin of the subject and a second end connected to a needle hub, the needle hub including a distal end connected to the second end of the needle shaft and a proximal end including a pair of diametrically opposed flanges extending radially. Each of the first and second housing portions includes at least two articulating transverse walls or protrusions extending from its inner surface, the at least two articulating transverse walls or protrusions forming a gap therebetween for receiving at least a portion of one or both of a pair of radially extending, diametrically opposed flanges of the needle unit to securely mount the needle unit within the housing. The proximal end of the housing, together with the at least two articulating transverse walls or protrusions of each of the first and second housing portions, defines a channel for receiving the syringe tip for engagement with the needle hub. The distal end of the housing includes a second contact surface, and the first end of the needle shaft extends outward from the second contact surface a predetermined distance to limit the penetration depth of the needle shaft. The needle adapter body is movably mounted to the foot to allow movement of the needle adapter body from a first position to a second position, wherein when the needle adapter body is in the first position, the needle shaft is in a retracted position so that the first end of the needle shaft does not extend beyond the first contact surface, and when the needle adapter body is in the second position, the first end of the needle shaft extends beyond the first contact surface and out of the second contact surface a predetermined distance to limit the penetration depth of the needle shaft.The assembly further includes friction means for preventing movement of the needle adapter body relative to the foot when the needle adapter body is in the first position until a predetermined static friction force is overcome, and for causing or allowing rapid acceleration of the needle adapter body towards the foot to increase the speed of the needle shaft to increase the chance of skin penetration. [Brief explanation of the drawings]

[0013] For a better understanding of the present invention, including the progression of its development to arrive at its final product, reference is made to the following description to be used in conjunction with the accompanying drawings.

[0014] [Figure 1(a)] 1 illustrates, in perspective view, an exemplary needle adapter according to an embodiment of the present application. [Figure 1(b)] FIG. 1(b) illustrates a top view of the needle adapter shown in FIG. 1(a), showing the proximal end of the housing and a channel formed therein for receiving a syringe tip. [Figure 1(c)] 1(a) illustrates a bottom view of the needle adapter 100 shown in FIG. 1(a), showing the distal end 106 of the housing 102, which includes a first contact surface 132 adapted to be placed on the skin of a subject, and a second contact surface 134 through which the first end 112 of the needle shaft 110 extends. [Figure 2(a)] Illustrated is the first housing portion 102a and the manner in which the needle unit 108 may engage with the first housing portion 102a. [Figure 2(b)] Illustrated is the first housing portion 102a and the manner in which the needle unit 108 may engage with the first housing portion 102a. [Figure 3(a)] FIG. 1(a) illustrates a partially disassembled needle adapter 100 showing a first housing portion 102a, a second housing portion 102b, and a needle unit 108 engaged with the first housing portion 102a in a first orientation. [Figure 3(b)]FIG. 1(a) illustrates a partially disassembled needle adapter 100 showing a first housing portion 102a, a second housing portion 102b, and a needle unit 108 engaged with the first housing portion 102a in a second orientation. [Figure 4(a)] To better illustrate how varying the placement of the needle unit 108 within the first housing portion 102a affects the predetermined distance d1 that the first end of the needle shaft 112 extends out from the second contact surface 134, a simplified first housing portion 102a of the needle adapter 100 is illustrated in which the distal end of the housing 106 lacks the first contact surface 132. [Figure 4(b)] To better illustrate how varying the placement of the needle unit 108 within the first housing portion 102a affects the predetermined distance d1 that the first end of the needle shaft 112 extends out from the second contact surface 134, a simplified first housing portion 102a of the needle adapter 100 is illustrated in which the distal end of the housing 106 lacks the first contact surface 132. [Figure 5] 5 depicts a further simplified view of the simplified first housing portion 102a shown in Figures 4(a) and 4(b), and also depicts a simplified first housing portion 202a of the needle adapter body 200 of the assembly 201 discussed in further detail below. In the labeling of Figure 5, references to components / elements of the needle adapter body 200 of the assembly 201 discussed below are provided in parentheses. [Figure 6] 1 illustrates a perspective view of first housing portion 102a, showing how a preselected portion p1 of the distal end of first housing portion 102a can be removed during assembly of needle adapter 100 to further account for manufacturer variations in needle shaft length. [Figure 7(a)] 1 shows a simplified cross-sectional view of one embodiment of a needle adapter 100 engaged with a syringe 146, thus forming an injection device 149 for administering a fluid to a subject via injection. [Figure 7(b)]1 shows a simplified cross-sectional view of one embodiment of a needle adapter 100 engaged with a syringe 146, thus forming an injection device 149 for administering a fluid to a subject via injection. [Figure 7(c)] 7(a) and (b) illustrate perspective views of the injection device 149 shown in FIG. [Figure 8] 1 illustrates a series of steps that may be used in administering a fluid to a subject via injection using needle adapter 100. [Figure 9(a)] A safety holder 152 is illustrated. [Figure 9(b)] A simplified cross-sectional view of one embodiment of a needle adapter 100 engaged with a syringe 146 and illustrating how the distal end 106 of the needle adapter housing 102 can be received in the open end 154 of the safety holder. [Figure 9(c)] Needle adapter housing 102 engaged with safety holder 152 is illustrated along with needle adapter 100 in simplified cross section. [Figure 9(d)] Needle adapter housing 102 engaged with safety holder 152 is illustrated along with needle adapter 100 in a simplified cross-sectional view, and with safety holder 152 and syringe 146 also in cross-sectional view. [Figure 10] Illustrated is the engagement of a syringe 146 with a dose metering device 160 and its engagement with a needle adapter 100. [Figure 11(a)] 2 illustrates, in perspective view, an exemplary assembly 201 for forming an injection device for administering a fluid to a subject, according to an embodiment of the present application. [Figure 11(b)] FIG. 11( a ) illustrates a top view of the assembly shown in FIG. 11( a ), showing the proximal end of the needle adapter housing and the channel formed therein for receiving the syringe tip. [Figure 11(c)] FIG. 11(b) illustrates a further perspective view of the assembly shown in FIG. 11(a). [Figure 11(d)]11(a) and (c) illustrate bottom views of the assembly 201 shown in Figures 11(a) and (c), showing the distal end 233 of the foot 231, which includes a first contact surface 232 adapted to be placed on the skin of a subject. A second contact surface 234 of the distal end 206 of the housing 202 of the needle adapter body 200, through which the first end 112 of the needle shaft 210 extends, is also visible through the opening 286 formed by the inner surface 288 of the foot, which is oriented in a plane substantially parallel to and spaced apart from the tangent plane defined by the first contact surface 232. [Figure 12] 11(a) and (c) illustrate exploded views of the assembly 201 shown in FIG. [Figure 13(a)] Illustrated is the first housing portion 202a and the manner in which the needle unit 208 may engage with the first housing portion 202a. [Figure 13(b)] Illustrated is the first housing portion 202a and the manner in which the needle unit 208 may engage with the first housing portion 202a. [Figure 14(a)] 10 illustrates the engagement of needle unit 208 with first housing portion 202a and the engagement of first housing portion 202a with second housing portion 202b to form housing 202 of needle adapter body 200. [Figure 14(b)] 10 illustrates the engagement of needle unit 208 with first housing portion 202a and the engagement of first housing portion 202a with second housing portion 202b to form housing 202 of needle adapter body 200. [Figure 14(c)] 10 illustrates the engagement of needle unit 208 with first housing portion 202a and the engagement of first housing portion 202a with second housing portion 202b to form housing 202 of needle adapter body 200. [Figure 15]An oblique view of needle adapter body 200 and foot 231 is illustrated, clearly showing at least two protrusions 274 extending from inner surface 276 of proximal end 278 of foot 231 and one of at least two corresponding grooves 280 located on outer surface 266 of distal end 206 of housing 202 of needle adapter body 200. [Figure 16] An enlarged perspective view of needle adapter body 200 is provided to better illustrate the contours of groove 280. [Figure 17(a)] One embodiment of assembly 201 is illustrated in perspective (top) and cross-sectional (bottom) views when safety clip 264 is removed and needle adapter body 200 is in a first position (i.e., ready for injection). [Figure 17(b)] Assembly 201 is illustrated in perspective (top) and cross-sectional (bottom) views with safety clip 264 removed and needle adapter body 200 in a second position (i.e., needle shaft 210 penetrates the skin). [Figure 17(c)] Assembly 201 is illustrated in perspective (top) and cross-sectional (bottom) views when needle adapter body 200 is held in a fixed, non-activated position against foot 231. [Figure 18(a)] 2 illustrates a proposed automated assembly line using machine vision and pick-and-place robotics techniques to prepare assembly 201. "Housing 1" and "Housing 2" refer to first and second housing portions 202a and 202b, "needle" refers to needle unit 208, "housing attachment" refers to attachment of needle unit 208 to one of first and second housing portions 202a / 202b, "pull pin" refers to safety clip 264, and "foot" refers to foot 231. The various elements are placed on a manufacturing conveyor that moves along the assembly line via a conveyor belt. [Figure 18(b)] 1 illustrates the configuration of a manufacturing conveyance device at each stage of assembly. [Figure 19] 2 illustrates a series of steps that may be used in administering a fluid to a subject via injection using assembly 201. [Figure 20(a)] 20(a) and (b) show simplified cross-sectional views of an alternative embodiment of assembly 201 engaged with syringe 246, thus forming injection device 249 for administering fluid to a subject via injection. As can be seen in FIGS. 20(a) and (b), the locking mechanism is not present and needle adapter body 200 is in the second position when needle shaft 210 penetrates skin 250 (shown in FIG. 20(b)). [Figure 20(b)] 20(a) and (b) show simplified cross-sectional views of an alternative embodiment of assembly 201 engaged with syringe 246, thus forming injection device 249 for administering fluid to a subject via injection. As can be seen in FIGS. 20(a) and (b), the locking mechanism is not present and needle adapter body 200 is in the second position when needle shaft 210 penetrates skin 250 (shown in FIG. 20(b)). [Figure 20(c)] 20(a) and (b) illustrate perspective views of the injection device 249 shown in FIG. 20(a) and (b). DETAILED DESCRIPTION OF THE INVENTION

[0015] definition Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0016] As used in this specification and claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0017] As used herein, the term "comprising" will be understood to mean that the following list is not exhaustive and may or may not include any other additional suitable items, e.g., one or more further features, components, ingredients, and / or elements, as appropriate.

[0018] As used herein, terms of degree such as "substantially," "about," and "approximately" refer to a reasonable amount of deviation from the modified term such that the end result is not significantly altered. These terms of degree should be interpreted as including a deviation of at least ±5% from the modified term if this deviation does not negate the meaning of the word it modifies.

[0019] The term "fluid" as used herein will be understood to mean any substance that can be injected through a needle, such as, for example, a liquid, solution, suspension, gel, or other substance that can be injected through a needle.

[0020] Terms such as "first," "second," etc. herein are used to distinguish between similar elements, and it will be understood that these terms may be interchangeable under certain circumstances. Additionally, terms such as "upper," "lower," etc. herein are used for descriptive purposes and may not represent relative positions. Specific features of one or more embodiments of the present application may be combined in any suitable manner, as would be understood by one of ordinary skill in the art in light of the teachings of the present application. Finally, the drawings provided herein are for illustrative purposes, and the illustrated elements may not be drawn to scale. In the drawings, like reference numerals refer to like parts throughout the various views and as described herein, unless otherwise specified.

[0021] Current state-of-the-art needle adapters and injection devices consist of a needle unit or an array of needle units attached to an adapter piece or other device by gluing, overmolding, etc. Such needle units typically include a plastic (e.g., polypropylene (PP)), metal, or stainless steel needle shaft that may potentially be within a flat glass hub.

[0022] Regarding overmolding: In this case, the needle unit / shaft is positioned in an injection molding tool within a purpose-built cavity (designed to keep the needle tip and part of the shaft plastic-free). A medical-grade plastic (e.g., cyclic olefin copolymer (COC)) is then overmolded to create a secure connection between the needle shaft and the hub / housing. The drawbacks of overmolding are that the process is difficult to automate (and, if not heavily automated, very expensive), requires complex tooling, is particularly challenging when very short needle shafts are required, is highly dependent on the precision and tolerance of the needle, and the needle tip can be damaged during the process.

[0023] Regarding adhesives: The needle shaft can be positioned and attached to the hub or housing (e.g., injection molded) with an adhesive, which would require a (semi-)automated system to hold the needle shaft, hold the housing, position the two components relative to each other, and attach the needle shaft with, for example, ultraviolet (UV) curing adhesive or silicone. The drawbacks of adhesives are that they can present biocompatibility issues (e.g., elements of the adhesive can be extracted / leached into the injected fluid), raise quality control issues (regarding positioning, device leakage, etc.), can be subject to creep in needle shaft / unit positioning over time (which can affect the length of the needle shaft for injection), are very difficult for short needle shafts, and are expensive to automate.

[0024] Additionally, current state-of-the-art needle adapters and injection devices claim to have a predetermined needle protrusion length of, e.g., 1 mm or, e.g., 13 mm. However, as a result of current state-of-the-art manufacturing processes, it is known that the final needle length will be subject to manufacturing tolerances of, e.g., 0.05 mm, or, e.g., 2 mm, as defined in certain ISO standards.

[0025] It will therefore be appreciated that the current state of the art is generally preferred for long needles (e.g. +5 mm) with wide tolerances (e.g. +:-0.5 mm), as this is only cheaper in that case (due to the dimensions and tolerances applied).

[0026] In light of the above, it will be appreciated that current techniques are inadequate when shallow penetration depths are required (requiring a shorter functional needle shaft length for injection, such as in the case of ID injections) because they are inaccurate, expensive, and prone to error.

[0027] The needle adapters and assemblies described herein for forming an injection device for administering fluids to a subject address the above-mentioned deficiencies and allow for control of penetration depth regardless of deviations in the intended needle length and tolerances. The needle adapters and assemblies of the present application enable the use of needle units with longer needle shafts, such as commercially available (pre-attached) needle units that include a needle shaft and hub with a standard female Luer lock fitting, ranging from 26 to 34 G and 12 mm in length. While such needle units may have long needle shafts with wide tolerances, the needle adapters and assemblies of the present application can accurately control penetration depth regardless. Thus, the needle adapters and assemblies of the present application can account for and compensate for manufacturer variations in needle shafts.

[0028] In one embodiment of the present application, there is provided a needle adapter for forming an injection device for administering a fluid to a subject, the needle adapter including: a housing formed from a first housing portion and a second housing portion, the housing having a proximal end and a distal end; and a needle unit fixedly mounted within the housing. The needle unit includes a needle shaft including a first end for piercing the skin of the subject and a second end connected to a needle hub, the needle hub including a distal end connected to the second end of the needle shaft and a proximal end including a pair of diametrically opposed radially extending flanges (e.g., typical needle hub tabs that may be found on commercially available needle units including needle shafts and hubs with standard female Luer lock fittings). Each of the first and second housing portions includes at least two articulating transverse walls or protrusions extending from its inner surface, the at least two articulating transverse walls or protrusions forming a gap therebetween for receiving at least a portion of one or both of a pair of radially extending, diametrically opposed flanges of the needle unit to securely mount the needle unit within the housing. The proximal end of the housing, together with the at least two articulating transverse walls or protrusions of each of the first and second housing portions, defines a channel sized and shaped to receive a syringe tip (e.g., a syringe tip having standard Luer dimensions) for engagement with the needle hub. The distal end of the housing includes a first contact surface adapted to be placed on the subject's skin and a second contact surface, and the first end of the needle shaft extends outward from the second contact surface a predetermined distance to limit the penetration depth of the needle shaft.

[0029] In another embodiment, the first and second housing portions are configured to snap-fit engage with one another to form the housing. As one skilled in the art will recognize, snap-fit engagement of the first and second housing portions is a very simple form of attachment that is fast and easily automated, offering advantages over other attachment methods such as adhesive bonding (the limitations of which are discussed above) or ultrasonic welding (which do not work for welding certain plastics together and would add complexity and cost to an automated assembly line). In another embodiment, the first and second housing portions are of at least substantially similar or identical configuration (which reduces tooling requirements and makes the device more economical to manufacture).

[0030] In another embodiment, at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit, when received in the gap between the first and second housing portions, has frictional engagement with opposing surfaces of at least two articulating transverse walls or protrusions of each of the first and second housing portions.

[0031] In yet another embodiment, the gap formed by the at least two articulating transverse walls or protrusions of each of the first and second housing portions is configured to receive at least a portion of one or both of a pair of radially extending, diametrically opposed flanges of the needle unit in one of a first and a second orientation of mounting of the needle unit, wherein the predetermined distance that the first end of the needle shaft extends from the second contact surface when the needle unit is mounted in the first orientation is a first predetermined distance and the predetermined distance that the first end of the needle shaft extends from the second contact surface when the needle unit is mounted in the second orientation is a second predetermined distance, and the first predetermined distance is different from the second predetermined distance.

[0032] In another embodiment, each of the first and second housing portions further includes a plurality of protrusions extending from an inner surface of the distal end of each of the first and second housing portions to form a needle guide configured to hold the needle shaft in place.

[0033] In another embodiment, the plurality of protrusions includes at least two needle stabilizing protrusions disposed on either side of the needle shaft and offset from one another along the longitudinal axis of the needle shaft, each of the at least two needle stabilizing protrusions having an inclined surface that abuts the needle shaft.

[0034] In yet another embodiment, the first contact surface is disposed along the periphery of the distal end of the housing and the second contact surface is disposed substantially centrally at the distal end of the housing. The second contact surface may be disposed at an end of a needle stabilization projection that may extend substantially centrally from the distal end of the housing.

[0035] In yet another embodiment, the housing is generally cylindrical in shape.

[0036] In another embodiment, each of the first and second housing portions is generally semi-cylindrical in shape.

[0037] In another embodiment, there is provided a method for assembling the needle adapter defined above, the method comprising: obtaining a first housing portion and a second housing portion; obtaining a needle unit; optionally measuring a length of the needle shaft; removing a preselected portion of a distal end of each of the first and second housing portions based on the length of the needle shaft; attaching the needle unit to one of the first and second housing portions by inserting at least a portion of one or both of a pair of radially extending diametrically opposed flanges of the needle unit into a gap formed between at least two adjoining transverse walls or protrusions; and engaging the first and second housing portions with each other to form a housing.

[0038] In yet another embodiment, there is provided a method for assembling the needle adapter defined above, the method comprising: obtaining a first housing portion and a second housing portion; obtaining a needle unit; measuring a length of the needle shaft; determining, based on the length of the needle shaft, whether the needle unit should be attached in the first orientation described above or the second orientation described above; optionally, removing a preselected portion of a distal end of each of the first and second housing portions based on the length of the needle shaft and whether the needle unit should be attached in the first orientation or the second orientation; attaching the needle unit to one of the first and second housing portions in the first or second orientation by inserting at least a portion of one or both of a pair of diametrically opposed radially extending flanges of the needle unit into a gap formed between at least two adjoining transverse walls or protrusions; and engaging the first and second housing portions to form a housing.

[0039] In another embodiment of the above-described method for assembling the needle adapter defined above, removing the preselected portion of the distal end of each of the first and second housing portions includes cutting the preselected portion of the distal end of each of the first and second housing portions, such as by laser cutting.

[0040] In yet another embodiment of the above-described method for assembling the above-defined needle adapter, the method is automated.

[0041] In another embodiment, an assembly for forming an injection device for administering a fluid to a subject is provided, the assembly including a foot including a first contact surface adapted to be placed on the subject's skin, the foot having a tubular shape for receiving a needle adapter body. The needle adapter body includes a housing formed from a first housing portion and a second housing portion, the housing having a proximal end and a distal end, and a needle unit fixedly mounted within the housing. The needle unit includes a needle shaft including a first end for piercing the subject's skin and a second end connected to a needle hub, the needle hub including a distal end connected to the second end of the needle shaft and a proximal end including a pair of diametrically opposed radially extending flanges (e.g., typical needle hub tabs that may be found on commercially available needle units including needle shafts and hubs with standard female Luer lock fittings). Each of the first and second housing portions includes at least two articulating transverse walls or protrusions extending from its inner surface, the at least two articulating transverse walls or protrusions forming a gap therebetween for receiving at least a portion of one or both of a pair of radially extending, diametrically opposed flanges of the needle unit to securely mount the needle unit within the housing. The proximal end of the housing, together with the at least two articulating transverse walls or protrusions of each of the first and second housing portions, defines a channel sized and shaped to receive a syringe tip (e.g., a syringe tip having standard Luer dimensions) for engagement with the needle hub. The distal end of the housing includes a second contact surface, and the first end of the needle shaft extends outward from the second contact surface a predetermined distance to limit the penetration depth of the needle shaft.The needle adapter body is movably mounted to the foot to enable movement of the needle adapter body from a first position to a second position, the needle shaft being in a retracted position such that the first end of the needle shaft does not extend beyond the first contact surface when the needle adapter body is in the first position, and the first end of the needle shaft extends beyond the first contact surface and out of the second contact surface a predetermined distance to limit the penetration depth of the needle shaft when the needle adapter body is in the second position. The assembly further includes friction means for preventing movement of the needle adapter body relative to the foot when the needle adapter body is in the first position until a predetermined static friction force is overcome, and for causing or enabling rapid acceleration of the needle adapter body toward the foot to increase the velocity of the needle shaft to increase the chance of penetration of the skin.

[0042] In another embodiment, the gap formed by the at least two articulating transverse walls or protrusions of each of the first and second housing portions is configured to receive at least a portion of one or both of a pair of radially extending diametrically opposed flanges of the needle unit in one of a first and a second orientation of mounting of the needle unit, wherein the predetermined distance that the first end of the needle shaft extends out from the second contact surface when the needle unit is mounted in the first orientation is a first predetermined distance and the predetermined distance that the first end of the needle shaft extends out from the second contact surface when the needle unit is mounted in the second orientation is a second predetermined distance, and the first predetermined distance is different from the second predetermined distance.

[0043] In another embodiment, at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit, when received in the gap between the first and second housing portions, has frictional engagement with opposing surfaces of at least two articulating transverse walls or protrusions of each of the first and second housing portions.

[0044] In another embodiment, the first and second housing portions are configured to snap-fit engage with one another to form the housing. As noted above, snap-fit engagement of the first and second housing portions is a very simple form of attachment that offers advantages over other attachment methods, such as adhesive bonding (the limitations of which are discussed above) or ultrasonic welding. In another embodiment, the first and second housing portions are of at least substantially similar or identical configuration (which reduces tooling requirements and makes the device more economical to manufacture).

[0045] In yet another embodiment, each of the first and second housing portions further includes a plurality of protrusions extending from an inner surface of the distal end of each of the first and second housing portions to form a needle guide configured to hold the needle shaft in place.

[0046] In yet another embodiment, the plurality of protrusions includes at least two needle stabilizing protrusions disposed on either side of the needle shaft and offset from one another along the longitudinal axis of the needle shaft, each of the at least two needle stabilizing protrusions having an inclined surface that abuts the needle shaft.

[0047] In another embodiment, the first contact surface is disposed around the periphery of the distal end of the housing and the second contact surface is disposed substantially centrally at the distal end of the housing. The second contact surface may be disposed at an end of a needle stabilization projection that may extend substantially centrally from the distal end of the housing.

[0048] In yet another embodiment, the housing is generally cylindrical in shape.In another embodiment, each of the first and second housing portions is generally semi-cylindrical in shape.

[0049] In another embodiment, the first friction means includes at least two protrusions extending from the inner surface of the proximal end of the foot in contact with at least two corresponding grooves located on the outer surface of the distal end of the needle adapter body housing, the radial dimension defined by the at least two protrusions prior to assembly of the needle adapter body and the foot being smaller than the radial dimension defined by the at least two corresponding grooves, and static friction is provided by radial clamping. However, it will be understood that the first friction means may equally include at least two protrusions extending from the outer surface of the body in contact with at least two corresponding grooves located on the inner surface of the foot, the radial dimension defined by the at least two protrusions prior to assembly of the body and the foot being larger than the radial dimension defined by the grooves, and static friction is provided by radial clamping.

[0050] In yet another embodiment, the at least two corresponding grooves are configured to prevent disengagement of the foot from the needle adapter body by limiting axial movement of the foot away from the needle adapter body following engagement of at least two protrusions extending from the inner surface of the proximal end of the foot with the at least two corresponding grooves.

[0051] In another embodiment, the at least two corresponding grooves are oriented generally parallel to the longitudinal axis of the housing.

[0052] In another embodiment, the assembly further includes at least two deactivation grooves located on an outer surface of the distal end of the housing of the needle adapter body, each of the at least two deactivation grooves intersecting one of the at least two corresponding grooves at an angle (e.g., about 25° to about 65°, e.g., about 45°) relative to the longitudinal axis of the housing such that axial movement of the foot away from the needle adapter body and rotation of the foot relative to the needle adapter body engages the at least two protrusions with the at least two deactivation grooves, each of the at least two deactivation grooves including a recess complementary to the shape of each of the at least two protrusions for securely engaging each of the at least two protrusions such that the needle adapter body is held in a fixed, deactivated position relative to the foot, and the first end of the needle shaft does not extend beyond the first contact surface when the needle adapter body is in the fixed, deactivated position relative to the foot.

[0053] In yet another embodiment, the assembly further includes a locking mechanism for providing locked and unlocked modes of the device, the locked mode being a mode of the assembly in which the needle adapter body is prevented from moving axially toward the foot even when an axial force greater than a predetermined static friction is exerted on the needle adapter body against the foot, and the unlocked mode being a mode of the assembly in which the needle adapter body is allowed to move toward the foot when an axial force greater than a predetermined static friction is exerted on the needle adapter body against the foot. In another embodiment, the locking mechanism includes a removable safety clip configured to engage a portion of the outer surface of the housing to maintain the foot and needle adapter body spaced apart and prevent the needle adapter body from moving axially toward the foot.

[0054] In another embodiment, there is provided a method for assembling the above-described assembly, the assembly optionally further including a locking mechanism including a detachable safety clip configured to engage a portion of an outer surface of the housing to maintain the foot and the needle adapter body spaced apart and prevent axial movement of the needle adapter body toward the foot, the method including obtaining the foot; obtaining first and second housing portions forming a housing for the needle adapter body; obtaining a needle unit; optionally obtaining the detachable safety clip; and, optionally, measuring a length of the needle shaft and, based on the length of the needle shaft, determining a second locking mechanism. The method includes removing a preselected portion of the distal end of each of the first and second housing portions; attaching the needle unit to one of the first and second housing portions by inserting at least a portion of one or both of a pair of radially extending, diametrically opposed flanges of the needle unit into a gap formed between at least two adjacent transverse walls or protrusions; engaging the first and second housing portions with each other to form a needle adapter body housing; engaging a detachable safety clip, if present, with a portion of the outer surface of the housing; and engaging the foot with the needle adapter body.

[0055] In yet another embodiment, there is provided a method for assembling the above-described assembly, the assembly optionally further including a locking mechanism including a detachable safety clip configured to engage a portion of an outer surface of the housing to maintain the foot and the needle adapter body spaced apart and prevent axial movement of the needle adapter body toward the foot, the method including obtaining the foot, obtaining first and second housing portions forming a housing for the needle adapter body, obtaining a needle unit, optionally obtaining the detachable safety clip, measuring a length of the needle shaft, determining whether the needle unit should be attached in a first orientation or a second orientation based on the length of the needle shaft, and optionally determining whether the needle unit should be attached in a second orientation based on the length of the needle shaft. and based on whether the needle unit is to be attached in a first orientation or a second orientation, removing a preselected portion of the distal end of each of the first and second housing portions; attaching the needle unit to one of the first and second housing portions in the first or second orientation by inserting at least a portion of one or both of a pair of radially extending, diametrically opposed flanges of the needle unit into a gap formed between at least two adjoining transverse walls or protrusions; engaging the first and second housing portions with each other to form a needle adapter body housing; engaging a detachable safety clip, if present, with a portion of an outer surface of the housing; and engaging the foot with the needle adapter body.

[0056] In another embodiment of the above-described method, engaging the foot with the needle adapter body includes engaging at least two protrusions extending from an inner surface of the proximal end of the foot with at least two corresponding grooves located on an outer surface of the distal end of the housing of the needle adapter body.

[0057] In another embodiment of the above-described method for assembling the above-defined assembly, removing the preselected portion of the distal end of each of the first housing portion and the second housing portion includes cutting the preselected portion of the distal end of each of the first housing portion and the second housing portion, such as by laser cutting.

[0058] In yet another embodiment of the above method for assembling the above defined assembly, the method is automated.

[0059] In another embodiment, a method of administering a fluid to a subject via injection is provided, the method comprising: (a) obtaining the needle adapter described above; (b) obtaining a syringe or other administration device, the other administration device including a dispensing tip similar in size and shape to a syringe tip (the channel being sized and shaped to receive the tip of the syringe / other administration device for engagement with a needle hub), the syringe or other administration device being loaded with the fluid to be administered to the subject; and (c) inserting the tip of the syringe or other administration device into a needle adapter disposed at the proximal end of a housing. (d) engaging the tip with the needle hub by inserting it into the channel; (d) engaging the first contact surface with the skin of the subject; (e) pressing the housing against the skin to penetrate the first end of the needle shaft through the skin; (f) expelling fluid from the syringe or other administration device through the needle shaft and into the subject; and (g) optionally engaging the needle adapter with a safety holder, the safety holder having an open end for receiving at least the distal end of the needle adapter housing and a closed end, the closed end including opposing wings for stabilizing the safety holder on a horizontal surface.

[0060] In another embodiment, a method of administering a fluid to a subject via injection is provided, the method including: (a) obtaining the above-described assembly, wherein the needle adapter body is in a first position; (b) obtaining a syringe or other administration device, wherein the other administration device includes a dispensing tip similar in size and shape to a syringe tip (the channel is sized and shaped to receive the tip of the syringe / other administration device for engagement with the needle hub), the syringe or other administration device being filled with a fluid to be administered to the subject; (c) inserting the tip of the syringe or other administration device into the channel disposed in the proximal end of the needle adapter housing to engage the tip with the needle hub; (d) engaging a first contact surface of the foot with the skin of the subject; (e) pushing the housing of the needle adapter body toward the foot to move the needle adapter body from the first position to a second position, thereby causing the first end of the needle shaft to pierce the skin; and (f) expelling fluid from the syringe or other administration device through the needle shaft and into the subject.

[0061] In yet another embodiment, wherein the above-described assembly includes a needle adapter housing having a deactivation groove, a method of administering a fluid to a subject via injection is provided, the method comprising: (a) obtaining the above-described assembly, wherein the needle adapter body is in a first position; (b) obtaining a syringe or other administration device, wherein the other administration device includes a dispensing tip similar in size and shape to a syringe tip (the channel is sized and shaped to receive the tip of the syringe / other administration device for engagement with the needle hub), the syringe or other administration device being filled with a fluid to be administered to the subject; and (c) inserting the tip of the syringe or other administration device into the channel disposed in the proximal end of the needle adapter housing, thereby (d) engaging the tip with the needle hub; (d) engaging a first contact surface of the foot with the skin of the subject; (e) pushing the housing of the needle adapter body axially toward the foot to move the needle adapter body from a first position to a second position, thereby causing the first end of the needle shaft to penetrate the skin; (f) expelling fluid from the syringe or other administration device through the needle shaft and into the subject; and (g) pulling the housing of the needle adapter body axially away from the needle adapter body and rotating the foot relative to the needle adapter body to engage the at least two protrusions with the at least two deactivation grooves and fixedly engage each of the at least two protrusions with a recess in each of the at least two deactivation grooves, such that the needle adapter body is held in a fixed, deactivated position relative to the foot.

[0062] In yet another embodiment, wherein the above-described assembly includes a needle adapter housing including a deactivation groove and a locking mechanism including a detachable safety clip, a method of administering a fluid to a subject via injection is provided, the method including: (a) obtaining the above-described assembly, wherein the needle adapter body is in a first position; (b) obtaining a syringe or other administration device, wherein the other administration device includes a dispensing tip similar in size and shape to a syringe tip (the channel is sized and shaped to receive the tip of the syringe / other administration device for engagement with the needle hub), the syringe or other administration device being filled with a fluid to be administered to the subject; (c) inserting the tip of the syringe or other administration device into the channel disposed at the proximal end of the needle adapter housing, thereby engaging the tip with the needle hub; and (d) contacting a first contact surface of the foot with the needle adapter housing. (e) axially pushing the housing of the needle adapter body toward the foot to move the needle adapter body from the first position to a second position, thereby causing the first end of the needle shaft to penetrate the skin; (f) expelling fluid from the syringe or other administration device through the needle shaft and into the subject; and (g) pulling the housing of the needle adapter body axially away from the needle adapter body and rotating the foot relative to the needle adapter body to engage the at least two protrusions with the at least two deactivation grooves, and fixingly engaging each of the at least two protrusions with a recess in each of the at least two deactivation grooves, such that the needle adapter body is held in a fixed, deactivated position relative to the foot, the method further comprising removing a safety clip from the outer surface of the housing after step (c) and before step (d), or after step (d) and before step (e).

[0063] Other administration devices that may be used in place of the syringe with needle adapter and assembly of the present application may include multi-chambered pre-filled containers (e.g., dual chambers for lyophilized material and diluent) having means for mixing the components of the chambers and means for expelling them from the administration device (e.g., by a plunger, etc.).

[0064] In another embodiment, a kit is provided comprising: the needle adapter described above to form an injection device for administering a fluid to a subject; a syringe or other administration device including a dispensing tip similar in size and shape to the syringe tip, optionally filled with a fluid to be administered to the subject; optionally a vial containing the fluid to be administered to the subject; optionally a detachable needle unit or other means for drawing fluid from the optional vial into the syringe or other administration device, the detachable needle unit being detachable to allow a tip of the syringe or other administration device to be inserted into a channel in the housing; optionally a safety holder having an open end for receiving at least the distal end of the needle adapter housing and a closed end, the closed end stabilizing the safety holder on a horizontal surface; and optionally instructions for use.

[0065] In another embodiment, a kit is provided, the kit including the above-described assembly for forming an injection device for administering a fluid to a subject; a syringe or other administration device including a dispensing tip similar in size and shape to the syringe tip, optionally filled with the fluid to be administered to the subject; optionally a vial containing the fluid to be administered to the subject; optionally a detachable needle unit or other means for drawing the fluid from the optional vial into the syringe or other administration device, the detachable needle unit being detachable to allow the tip of the syringe or other administration device to be inserted into a channel in the housing; and optionally instructions for use.

[0066] In yet another embodiment, an injection device is provided that includes the needle adapter described above and a syringe or other administration device that includes a dispensing tip similar in size and shape to the syringe tip, and the syringe or other administration device is optionally filled with a fluid to be administered to a subject.

[0067] In yet another embodiment, an injection device is provided that includes the above-described assembly and a syringe or other administration device that includes a dispensing tip similar in size and shape to the syringe tip, and the syringe or other administration device is optionally filled with a fluid to be administered to a subject.

[0068] The various components of the needle adapter, as well as the assembly for forming the injection device for administering fluid to a subject, can be formed from plastic materials, particularly medical-grade plastics (e.g., cyclic olefin copolymer (COC)), and can be manufactured by several different methods, such as precision casting, additive manufacturing, 3D printing, and injection molding. In one embodiment, the components are manufactured using injection molding. The tolerances of such processes can be precisely controlled, for example, on the order of 0.01 mm, or 0.02 mm, or 0.03 mm, allowing for precise construction of the device, including precise implementation of frictional forces, as described in more detail below.

[0069] Those skilled in the art will appreciate that the needle adapter and assembly to form an injection device for administering fluids to a subject can be used to administer a variety of drugs or vaccines. These devices are particularly well-suited for providing injections at highly precise angles and / or penetration depths, such as for ID injections, where the needle is oriented nearly perpendicular to the skin and inserted to a highly precise, predetermined depth, typically about 1.0 mm, with a tolerance of + / - 0.10 mm, + / - 0.05 mm, or even less, although other specific angles can also be used. However, it will be appreciated that the present invention is not limited to ID injections and can also be used for IV, SC, or IM injections, although in these cases the needle will typically have a greater length, e.g., at least 5 mm or at least 10 mm. As those skilled in the art will recognize, the angle and / or penetration depth and / or positioning of the device can be variously selected for such types of injections.

[0070] In one embodiment, the needle adapter described herein allows fluid to be administered with a single hand, making such devices suitable for self-administration. For example, with respect to the needle adapter, a syringe can be filled with an active agent-containing fluid, and the syringe has a plunger for dispensing the fluid. The user can then insert the tip of the syringe into a channel disposed at the proximal end of the housing. The first contact surface of the needle adapter can then be placed on the skin, and the needle adapter can be pressed into the skin to insert the first end of the needle shaft into the skin. Finally, a force can then be applied to the syringe plunger (e.g., with the index or forefinger) to deliver the fluid into the user's body through the needle shaft.

[0071] In another embodiment, the needle adapter can be used to deliver multiple doses of liquid. In another embodiment, the needle adapter can be connected to a syringe-compatible dose metering device (the tip of the syringe enters a channel in the device and the dose metering device controls the amount of fluid to be delivered in single dose units). In another embodiment, the needle adapter can be connected to another administration device having a dispensing tip similar in size and shape to a syringe tip, such as a syringe tip with standard luer dimensions.

[0072] In another embodiment, the assemblies described herein allow fluids to be administered with a single hand, making such devices suitable for self-administration. For example, a syringe can be filled with an active agent-containing fluid and have a plunger for dispensing the fluid. The user can then insert the tip of the syringe into a channel disposed at the proximal end of the needle adapter body housing. Administration steps can include: 1) holding the assembly in one hand (e.g., between the thumb and middle finger); 2) gently placing the assembly on the skin; 3) pushing the needle adapter body toward the foot until frictional forces are overcome, thereby inserting the first end of the needle shaft into the skin (with a nearly 100% probability of penetration and a highly accurate, predetermined penetration depth); and 4) applying force to the syringe plunger (e.g., with the index or forefinger) to deliver the fluid through the needle shaft to the subject. In other embodiments, the step of administering can include pushing the needle adapter body toward the foot to disengage a locking mechanism, such as a removable safety clip, to activate the device before inserting the first end of the needle shaft into the skin, as described above and in more detail below. In another embodiment, the step of administering can include placing the needle adapter body in a fixed, deactivated position relative to the foot after administering the fluid to the subject. The assemblies described herein are particularly suitable for single use.

[0073] In another embodiment, the needle adapter body can be coupled to another administration device having a dispensing tip similar in size and shape to a syringe tip, such as a syringe tip having standard luer dimensions. It will be understood that the channel is sized and shaped to receive the tip of the syringe / other administration device for engagement with the needle hub.

[0074] It will be further appreciated that the present needle adapter and assembly to form an injection device for administering a fluid to a subject requires minimal skill and experience to administer the fluid correctly, as opposed to, for example, the Mantoux technique for administering an ID injection. In addition, the risk of non-penetration or incomplete penetration of the needle shaft into the skin (to the predetermined penetration depth) is dramatically reduced or almost completely eliminated, as is the risk of inserting the needle shaft too deeply. Thus, with the present needle adapter and assembly, it is nearly guaranteed that the skin will be penetrated and the needle tip will be located at the predetermined depth. This can help reduce pain experienced by the subject and / or improve the therapeutic efficacy of the active agent being administered.

[0075] With regard to the above-described assemblies, no spring (internal or external mechanism for compressing, holding, and releasing such a spring) is required to insert the needle shaft, but instead, in the assembly of the present application, force / pressure / potential energy and / or kinetic energy is stored / provided in the hand and / or forearm and / or fingers of the person holding the assembly, and again, the device includes a mechanism (by static friction) that allows or nullifies this (external) force to take effect. The spring can be used in an injection device using this assembly to actuate, for example, a plunger, but this is independent of the insertion of the needle shaft into the skin.

[0076] The friction means, which establishes or defines the force / pressure / potential energy accumulated before the needle begins to move, can be passively defined, for example, by a clamping force between a portion of the needle adapter body (also referred to herein as the "body") and the foot (described in more detail below). This causes the needle to suddenly accelerate once the static friction force is overcome, resulting in the needle penetrating the skin at a relatively high speed (e.g., 2 m / s to 15 m / s, or any other suitable speed). The predetermined static friction force can be a value ranging from about 1.0 to about 20.0 Newtons, or from about 1.5 to about 15 Newtons, or from about 2.0 to about 10 Newtons, or from about 5.0 to about 7.5 Newtons; preferably, the static friction force is at least about 2.0 Newtons. The optimum penetration rate, and therefore the optimum friction, may be selected differently for different needle units (e.g., different diameters, different lengths, different angles, etc.), and different customized assemblies (e.g., having the above-mentioned grooves and / or protrusions with different surface characteristics) may be made with different needle units.

[0077] In one embodiment, the angle between the longitudinal axis of the needle shaft and the tangent plane defined by the first contact surface is, for example, between about 5° and about 175°, between about 10° and about 170°, between about 60° and about 120°, for example, between about 80° and about 100°, for example, about 90°. Thus, the present needle adapter and assembly allows for angled ID injection, administering ID drugs at an angle between about 5° and about 15°, and differing from the Mantoux technique, which is known to be painful for patients. It is believed that inserting the needle at an angle less than approximately 90° significantly reduces pain and may also allow for better diffusion of injected fluid between cells.

[0078] In one embodiment, the predetermined distance that at least one needle shaft extends from the second contact surface is a distance in the range of 0.25 to 12.0 mm, or 0.25 to 5.00 mm, or 0.25 to 2.00 mm. A distance of 5.0 mm to 12.0 mm, e.g., 10 mm to 120 mm, may be particularly suitable for IM injection. A distance of 0.25 mm to 8.00 mm, e.g., 1.00 mm to 5.00 mm, may be particularly suitable for SC injection. A distance of 0.25 mm to 3.00 mm may be particularly suitable for ID injection.

[0079] FIG. 1(a) illustrates a perspective view of an exemplary needle adapter 100 according to one embodiment of the present application. The needle adapter 100 includes a housing 102 formed from a first housing portion 102a and a second housing portion 102b, the housing having a proximal end 104 and a distal end 106. FIG. 1(b) illustrates a top view of the needle adapter 100 shown in FIG. 1(a), showing the proximal end 104 of the housing 102 of the needle adapter 100 of FIG. 1(a). FIG. 1(c) illustrates a bottom view of the needle adapter shown in FIG. 1(a). In this embodiment, the first housing portion 102a and the second housing portion 102b are identical and can be formed using injection molding of medical-grade plastic (e.g., COC), which provides very economical production. In the embodiment shown, the housing 102 is generally cylindrical in shape, with the first housing portion 102a and the second housing portion 102b each being generally semi-cylindrical in shape.

[0080] The needle unit 108 is fixedly mounted within the housing 102. Figures 2(a) and 2(b) illustrate the first housing portion 102a and the manner in which the needle unit 108 can be engaged with the first housing portion 102a, i.e., in a first orientation shown in Figure 2(a) and a second orientation shown in Figure 2(b). After the needle unit 108 is engaged with the first housing portion 102a, the second housing portion 102b is then engaged with the first housing portion 102a to form the needle adapter 100. As one skilled in the art will recognize, given that the first and second housing portions 102a, 102b, are of identical configuration, the needle unit is equally capable of engaging with the second housing portion 102b in the same manner as shown with the first housing portion 102a in Figures 2(a) and 2(b).

[0081] Figure 3(a) shows the component parts of needle adapter 100 with needle unit 108 engaged with first housing portion 102a in a first orientation, with second housing portion 102b configured to engage with first housing portion 102a to form housing 102. Figure 3(b) shows the component parts of needle adapter 100 with needle unit 108 engaged with first housing portion 102a in a second orientation, with second housing portion 102b configured to engage with first housing portion 102a to form housing 102.

[0082] 2(a) and 2(b) and 3(a) and 3(b), needle unit 108 includes a needle shaft 110 including a first end 112 for penetrating the skin of a subject and a second end 114 connected to a needle hub 116. Needle hub 116 includes a distal end 118 connected to the second end of needle shaft 114 and a proximal end 120 including a pair of diametrically opposed radially extending flanges 122. In the embodiment shown, needle hub 116 has typical needle hub tabs that would be found on a commercially available needle unit that includes a needle shaft and a hub with a standard female Luer lock fitting. Each of the first and second housing portions 102a, 102b includes at least two articulating transverse walls or protrusions 124 extending from an inner surface 126 thereof, the at least two articulating transverse walls or protrusions 124 forming a gap 128 therebetween for receiving at least a portion of one or both of the pair of radially extending, diametrically opposed flanges 122 of the needle unit 108 for fixedly mounting the needle unit 108 within the housing 102. The proximal end 104 of the housing 102, together with the at least two articulating transverse walls or protrusions 124 of each of the first and second housing portions 102a, 102b, define a channel 130 for receiving a syringe tip for engagement with the needle hub 116. The distal end 106 of the housing 102 includes a first contact surface 132 adapted to be placed on the skin of a subject and a second contact surface 134, with the first end of the needle shaft extending from the second contact surface a predetermined distance "d1" to limit the penetration depth of the needle shaft 110. In the embodiment shown, the first contact surface 132 is disposed along the periphery of the distal end 106 of the housing 102, and the second contact surface 134 is disposed substantially centrally at the distal end 106 of the housing 102. Specifically, the second contact surface is disposed at the end of a needle stabilizing protrusion 135 that extends substantially centrally from the distal end of the housing.

[0083] 4(a) and 4(b) illustrate a simplified first housing portion 102a of the needle adapter 100, in which the distal end of the housing 106 lacks the first contact surface 132, to better illustrate how varying the placement of the needle unit 108 within the first housing portion 102a affects the predetermined distance d1 that the first end of the needle shaft 112 extends from the second contact surface 134. As noted above, current state-of-the-art manufacturing processes are known to result in final needle lengths subject to manufacturing tolerances of, for example, 0.05 mm, or, for example, 2 mm, as defined in certain ISO standards. The needle adapters described herein allow for control of penetration depth regardless of intended needle length and tolerance variations. The needle adapters of the present application enable the use of needle units with longer needle shafts, such as commercially available (pre-glued) needle units including needle shafts and hubs with standard female Luer lock fittings, for example, 26-34G and 12 mm long. While such needle units may have long needle shafts with wide tolerances, the needle adapter of the present application can accurately control the penetration depth regardless, thus accounting for and compensating for manufacturer variations in needle shafts.

[0084] As can be seen in Figures 2(a) and 2(b), 3(a) and 3(b), and 4(a) and 4(b), a gap 128 formed by at least two articulating transverse walls or protrusions 124 of first housing portion 102a is configured to receive at least a portion of one or both of the pair of radially extending, diametrically opposed flanges 122 of needle unit 108 in one of a first (Figure 4(a)) and second (Figure 4(b)) orientations of attachment of the needle unit. As best seen in Figures 4(a) and 4(b), the first and second orientations of attachment of the needle unit may differ from one another by approximately a 90 degree rotation. At least one of the at least two articulating transverse walls or protrusions 124 of the first housing portion 102a has a step stop or shoulder 125 that engages the distal end 118 of the needle hub 116 and facilitates securely mounting the needle unit 108 in either the first or second orientation. The flange 122 of the needle unit 108 has frictional engagement with opposing surfaces of the at least two articulating transverse walls or protrusions 124 of each of the first and second housing portions 102a, 102b when received in the gap 128 therebetween, thus avoiding the need to use less desirable means, such as adhesives, overmolding, etc., for securely engaging the needle unit within the housing, as discussed above.

[0085] As best shown in FIG. 4(a), when the needle unit 108 is mounted in a first orientation (i.e., when the distal end 118 of the needle hub 116 is oriented with the pair of diametrically opposed radially extending flanges 122 extending directly into and out of the plane of the paper in FIG. 4(a) - this is also referred to herein as the flanges being disposed in a "vertical" position, i.e., position V), the predetermined distance d1 that the first end 112 of the needle shaft 110 extends out from the second contact surface 134 is a first predetermined distance d1a. As best shown in FIG. 4(b), when the needle unit 108 is mounted in a second orientation (i.e., when the distal end 118 of the needle hub 116 is oriented with the pair of radially extending, diametrically opposed flanges 122 extending from side to side as shown in FIG. 4(b)—also referred to herein as the flanges being disposed in a “horizontal” position, i.e., position H), the predetermined distance d1 that the first end 112 of the needle shaft 110 extends out from the second contact surface 134 is a second predetermined distance d1b. As illustrated in FIGS. 4(a) and 4(b), the first predetermined distance d1a is different from the second predetermined distance d1b.

[0086] Again, the above description refers to the first housing portion 102a, but given that the first housing portion 102a and the second housing portion 102b are of identical construction, it will be understood that the first housing portion 102a is interchangeable with the second housing portion 102b.

[0087] FIG. 5 depicts a further simplified view of the simplified first housing portion 102a shown in FIGS. 4(a) and 4(b) and also depicts a simplified first housing portion 202a of the needle adapter body 200 of the assembly 201, discussed in more detail below. In the labeling of FIG. 5 and the following description, references to components / elements of the needle adapter body 200 of the assembly 201, discussed below, are provided in parentheses. The needle unit 108 (208) is engaged with the first housing portion 102a (202a). FIG. 5 illustrates the effect of the orientation of the needle unit 108 (208) on a predetermined distance d1 (d2) that the first end 112 (212) of the needle shaft 110 (210) extends from the second contact surface 134 (234). Table 1 illustrates this in further detail. [Table 1]

[0088] 5, L1 denotes the length of the needle shaft 110 (210), e.g., 12 mm, and L2 denotes the length of the needle shaft within the device (two possible orientations), e.g., 11.00 mm for the radially extending diametrically opposed flange pair 122 (222) extending directly into and out of the plane of the paper (vertical position), and 11.25 mm for the radially extending diametrically opposed flange pair 122 (222) extending left and right. L3 denotes the predetermined distance d1 (e.g., d1a or d1b for the needle adapter 100, and d2a or d2b for the needle adapter body 200 of the assembly 201) that the first end 112 (212) of the needle shaft 110 (210) extends out from the second contact surface 134 (234) (i.e., the penetration depth of the needle shaft).

[0089] Referring to Table 1, for a 31G needle, an exemplary desired length L3 (predetermined distance d1 (d2)) is 0.85 mm. It is even more desirable to have this value within a specified tolerance, e.g., ±0.10 mm (hence, a 0.20 mm tolerance band for L3, assuming a range of 0.75-0.95 mm). Our experience has shown that standard 31G needles, e.g., with an L1 of 12 mm, have manufacturing tolerances that can significantly exceed the desired specified tolerance, e.g., ±0.10 mm. Therefore, if the needle adapter does not provide a means to account for manufacturer variations in the needle shaft, the ability to use commercially available needle units would be severely hindered. However, by mounting the needle unit 108 (208) in two different orientations within the housing 102 (202) and having the ability to adjust the predetermined distance d1 (d2) that the first end 112 (212) of the needle shaft 110 (210) extends from the second contact surface 134 (234), it is possible to effectively double the tolerance band, for example, to 0.45 mm, as illustrated in FIG. 5 and Table 1. For example, if the two L2 positions have a distance difference of, for example, 0.25 mm (11.00 vs. 11.25 mm), it is possible to operate within a specified tolerance of, for example, + / - 0.10 mm for needle shaft lengths ranging from 11.75 to 12.20 mm (which, in the inventors' experience, is more realistic). Thus, the needle adapters and assemblies of the present application (discussed below) have the significant advantage of being able to account for and compensate for manufacturer variations in needle shafts.

[0090] As can be seen in Figures 2(a) and (b) and 3(a) and (b), the first and second housing portions 102a, 102b are configured to snap-fit engage with one another to form the housing 102. This is achieved by fasteners (i.e., snaps) 136 protruding from the inner surface of each of the first and second housing portions 102a, 102b, which are configured to engage with complementary slots 138 formed in the interior portions of the housing of each of the first and second housing portions 102a, 102b in a snap-fit engagement. Each of the first and second housing portions 102a, 102b also has complementary ribs 140a and 140b that further assist in the engagement of the first and second housing portions 102a, 102b to form the housing 102. Thus, the snap-fit engagement of the first housing portion 102a and the second housing portion 102b to form the housing 102 is a simple and straightforward means for securing and joining these two components of the housing 102 together and does not require the use of adhesives or other means for joining these components.

[0091] As can be seen particularly in FIGS. 3(a) and 3(b) and 4(a) and 4(b) (also present in FIGS. 2(a) and 2(b), but not specifically labeled for ease of reading the remainder of the graphic labeling), each of the first and second housing portions 102a, 102b further includes a plurality of protrusions 142 extending from the inner surface 126 of its distal end to form a needle guide 144 configured to hold the needle shaft 110 in place. In the embodiment shown, the plurality of protrusions includes at least two needle stabilizing protrusions 142 disposed on either side of the needle shaft 110 and offset from one another along the longitudinal axis of the needle shaft 110, each having an inclined surface that abuts the needle shaft. These features of the needle adapter stabilize the needle shaft and hold it in a fixed position upon assembly of the first and second housing portions 102a, 102b to form the housing 102.

[0092] In embodiments such as those shown in Figures 1(a)-(c), 2(a), and (b), the angle between the longitudinal axis of the needle shaft 110 and the tangent plane defined by the first contact surface 132 is approximately 90°. It will be understood by those skilled in the art that this angle can be varied (e.g., to be within a range of about 5° to about 175°, about 10° to about 170°, about 60° to about 120°, e.g., about 80° to about 100°) by adjusting the angle at which the at least two articulating transverse walls or protrusions 124 extend from the inner surface 126 of the first / second housing portion (102a / 102b) along with the positioning of other support features (e.g., needle guide 144).

[0093] As noted above, features of needle adapter 100 can account for and compensate for manufacturer variations in needle shafts by having the ability to mount needle unit 108 in two different orientations within housing 102. If further adjustment of the predetermined distance d1 that first end 112 of needle shaft 110 extends from second contact surface 134 is required, this can be done during assembly of the needle adapter. Thus, a method for assembling a needle adapter may include obtaining a first housing portion 102a and a second housing portion 102b, obtaining a needle unit 108, measuring the length of the needle shaft 110, determining whether the needle unit 108 should be attached in a first orientation or a second orientation based on the length of the needle shaft 110, and optionally removing a preselected portion p1 of a distal end of each of the first housing portion 102a and the second housing portion 102b based on the length of the needle shaft 110 and whether the needle unit 108 should be attached in the first orientation or the second orientation. The needle unit can then be attached to one of the first and second housing portions 102a, 102b in either the first or second orientation by inserting at least a portion of one or both of the pair of radially extending, diametrically opposed flanges 122 of the needle unit 108 into the gap 128 formed between the at least two articulating transverse walls or protrusions 124 and engaging the first and second housing portions 102a, 102b with one another to form the housing 102. Figure 6 illustrates a perspective view of the first housing portion 102a and shows how a preselected portion p1 of the distal end of the first housing portion 102a can be removed during assembly of the needle adapter 100 to further account for manufacturer variations in needle shaft length (the preselected portion p1 is shown in exaggerated detail for clarity). It will be appreciated that the same preselected portion p1 of the distal end of second housing portion 102b will also then be removed during assembly of needle adapter 100.

[0094] Removing the preselected portion p1 of the distal end of each of the first and second housing portions 102 a and 102 b may include cutting the preselected portion p1 of the distal end of each of the first and second housing portions 102 a and 102 b, such as by laser cutting. The assembly process may be further automated such that a vision / imaging system (e.g., based on a CCD camera) on an automated assembly line ("machine vision") can determine the length of the needle shaft (e.g., to within 0.005 mm), the orientation of the needle unit, and whether removal of the preselected portion of the distal end of each of the first and second housing portions is required.

[0095] A method of administering a fluid to a subject via injection using the needle adapter described above includes: (a) obtaining a needle adapter body; (b) obtaining a syringe or other administration device, the other administration device including a dispensing tip similar in size and shape to the syringe tip, the syringe or other administration device being filled with a fluid to be administered to the subject; (c) engaging the tip of the syringe or other administration device with the needle hub by inserting the tip into a channel disposed in the proximal end of the housing; (d) engaging the first contact surface with the skin of the subject; (e) pressing the housing against the skin to cause the first end of the needle adapter body to penetrate the skin; and (f) expelling fluid from the syringe or other administration device through the needle shaft and into the subject.

[0096] 7(a) and (b) show simplified cross-sectional views of one embodiment of a needle adapter 100 engaged with a syringe 146, thus forming an injection device 149 for administering a fluid to a subject via injection. FIG. 7(c) illustrates a perspective view of the injection device 149 shown in FIGS. 7(a) and (b).

[0097] As shown in Figures 7(a) and (b), the tip 148 of a syringe (or another administration device) can be inserted into the channel 130 disposed in the proximal end 104 of the housing 102, thereby engaging the tip 148 with the needle hub 116. As shown in Figure 7(b), the first contact surface 132 engages the subject's skin 150. Pressing the housing 102 against the skin 150 allows the first end 112 of the needle shaft 110 (extending from the second contact surface 134) to penetrate the skin 150. Fluid can then be expelled from the syringe 146 (or other administration device) through the needle shaft 110 and into the subject.

[0098] 8 illustrates a series of steps that may be used in administering a fluid to a subject via injection using needle adapter 100. Following step 6, the syringe, used detachable needle unit, and needle adapter may be disposed of in an appropriate sharps container.

[0099] The needle adapter 100 described above is particularly well-suited for delivering multiple injections of fluid to a subject, which may be desirable for certain applications, such as stem cell transplantation. The predetermined distance d1 (penetration depth of the needle shaft 110) for such applications may be, for example, about 1.5 mm.

[0100] For added safety, the needle adapter housing 102 with the protruding first end 112 of the needle shaft 110 can be held in a safety holder 152 to prevent needlestick injuries when the device is not in use (e.g., before or after an injection). Figures 9(a)-(d) illustrate the safety holder 152, which has an open end 154 for receiving at least the distal end 106 of the needle adapter housing 102 and a closed end 156, the closed end 156 including opposing wings 158 for stabilizing the safety holder 152 on a horizontal surface. Figure 9(a) illustrates the safety holder 152. Figure 9(b) illustrates a simplified cross-sectional view of one embodiment of the needle adapter 100 engaged with a syringe 146 and how the distal end 106 of the needle adapter housing 102 can be received in the open end 154 of the safety holder. Figure 9(c) illustrates the needle adapter housing 102 engaged with the safety holder 152, along with a simplified cross-sectional view of the needle adapter 100. Figure 9(d) illustrates the needle adapter housing 102 engaged with the safety holder 152, along with a simplified cross-sectional view of the needle adapter 100, and also with a cross-sectional view of the safety holder 152 and syringe. In the embodiment shown, the safety holder 152 includes a recess around the open end 154 that is configured to engage the first contact surface 132 of the needle adapter housing 102.

[0101] As noted above, the needle adapter 100 can be coupled to a dose metering device 160 compatible with a syringe 146, where the tip of the syringe 148 fits into the channel 130 (not shown) of the needle adapter 100, and the dose metering device 160 has a plunger 162 that controls the amount of fluid delivered in single dose units. This can allow for the injection of multiple doses, such as 0.01 or 0.2 mL, e.g., 0.05 mL. FIG. 10 illustrates the engagement of the syringe 146 with the dose metering device 160 and its engagement with the needle adapter 100. Fasteners, such as push fittings or snaps, can be used to achieve a secure engagement between the dose metering device 160 and the needle adapter 100. Alternatively, or in addition, as noted above, other administration devices besides syringes can be engaged with the needle adapter 100, including dispensing tips similar in size and shape to the tips of syringes. Such other administration devices may include multi-chambered pre-filled containers (e.g., dual chambers for lyophilized material and diluent) having means for mixing the components of the chambers and means for expelling them from the administration device (e.g., by a plunger, etc.).

[0102] Figures 11(a) and (c) illustrate, in two slightly different perspective views, an assembly 201 for forming an injection device for administering a fluid to a subject. Figure 11(b) illustrates a top view of the assembly shown in Figures 11(a) and (c), and Figure 11(d) illustrates a bottom view of the assembly shown in Figures 11(a) and (c). Figure 12 illustrates an exploded view of the assembly shown in Figures 11(a) and (c).

[0103] As can be seen from Figures 11(a)-(d) and 12, the assembly 201 includes a foot 231 including a first contact surface 232 adapted to be placed on the skin of a subject, and the foot 231 has a tubular shape for receiving the needle adapter body 200.

[0104] 12, needle adapter body 200 includes a housing 202 formed from first and second housing portions 202a and 202b, the housing 202 having a proximal end 204 and a distal end 206, and a needle unit 208 fixedly mounted within the housing 202. As with needle adapter 100 described above, in this embodiment, first and second housing portions 202a and 202b are identical in construction and can be formed using injection molding of medical-grade plastic (e.g., COC), which provides highly economical production. In the embodiment shown, housing 202 is generally cylindrical in shape, with first and second housing portions 202a and 202b each being generally semi-cylindrical in shape.

[0105] 13(a) and 13(b) illustrate the first housing portion 202a and the manner in which the needle unit 208 can be engaged with the first housing portion 202a, showing the first housing portion 202a in front and side views with the needle unit 208 engaged with the first housing portion 202a. Referring to FIG. 12 and FIGS. 13(a) and (b), the needle unit 208 includes a needle shaft 210 including a first end 212 for penetrating the skin of a subject and a second end 214 connected to a needle hub 216. The needle hub 216 includes a distal end 218 connected to the second end 214 of the needle shaft 210 and a proximal end 220 including a pair of diametrically opposed radially extending flanges 222 (only one of which is visible in FIGS. 12 and 13(a)). In the embodiment shown, the needle hub 216 has typical needle hub tabs that would be found on a commercially available needle unit that includes a needle shaft and a hub with a standard female luer lock fitting.

[0106] Each of the first and second housing portions includes at least two articulating transverse walls or protrusions 224 extending from an inner surface 226 thereof, the at least two articulating transverse walls or protrusions 224 forming a gap 228 therebetween for receiving at least a portion of one or both of the pair of radially extending, diametrically opposed flanges 222 of the needle unit 208 for fixedly mounting the needle unit 208 within the housing 202. The proximal end 204 of the housing 202, together with the at least two articulating transverse walls or protrusions 224 of each of the first and second housing portions 202a, 202b, define a channel 230 for receiving a syringe tip for engagement with the needle hub 216. The distal end 206 of the housing 202 includes a second contact surface 234, and the first end 212 of the needle shaft 210 extends from the second contact surface 234 a predetermined distance d2 (e.g., d2a or d2b) to limit the penetration depth of the needle shaft. In the embodiment shown, the first contact surface 232 is disposed along the periphery of the distal end 233 of the foot 231, and the second contact surface 234 is substantially centrally disposed at the distal end 206 of the housing 202. Specifically, the second contact surface 234 is disposed at the end of a needle stabilizing projection 235 that extends substantially centrally from the distal end 206 of the housing 202.

[0107] As described in further detail below, the needle adapter body 200 is movably mounted to the foot 231 to enable movement of the needle adapter body 200 from a first position to a second position, wherein when the needle adapter body 200 is in the first position, the needle shaft 210 is in a retracted position such that the first end 212 of the needle shaft 210 does not extend beyond the first contact surface 232, and when the needle adapter body 200 is in the second position, the first end 212 of the needle shaft 210 extends beyond the first contact surface 232 and out of the second contact surface 234 by a predetermined distance d2 to limit the penetration depth of the needle shaft. The assembly further includes friction means for preventing movement of the needle adapter body 200 relative to the foot 231 when the needle adapter body 200 is in the first position until a predetermined static friction force is overcome, and for causing or allowing rapid acceleration of the needle adapter body 200 towards the foot 231 to increase the speed of the needle shaft 210 to increase the chance of penetration of the skin.

[0108] As noted above, FIGS. 13(a) and 13(b) illustrate the first housing portion 202a and the manner in which the needle unit 208 can be engaged with the first housing portion 202a, i.e., in a first orientation shown in FIG. 13(a) and a second orientation shown in FIG. 13(b). In a similar manner as described above with respect to the needle adapter 100, varying the placement of the needle unit 208 within the first housing portion 202a affects the predetermined distance d2 that the first end of the needle shaft 212 extends from the second contact surface 234. As noted above, current state-of-the-art manufacturing processes are known to result in final needle lengths subject to manufacturing tolerances of, for example, 0.05 mm, or, for example, 2 mm, as defined in certain ISO standards. The needle adapter body, which forms part of the assembly described herein, allows for control of penetration depth regardless of the intended needle length and tolerance deviations. Thus, the present assembly 201 allows for the use of needle units with longer needle shafts, such as commercially available (pre-glued) needle units including needle shafts and hubs with standard female Luer lock fittings, for example, 26-34G and 12mm long. While such needle units may have long needle shafts with wide tolerances, the present assembly 201 can independently precisely control penetration depth, thereby accounting for and compensating for manufacturer variations in needle shafts.

[0109] As best seen in Figures 13(a) and (b), a gap 228 formed by at least two articulating transverse walls or protrusions 224 of the first housing portion 102a is configured to receive at least a portion of one or both of the pair of radially extending, diametrically opposed flanges 222 of the needle unit 208 in one of a first (Figure 13(a)) and second (Figure 13(b)) orientations for mounting the needle unit 208. As best seen in Figures 13(a) and 13(b), the first and second orientations for mounting the needle unit may differ from one another by approximately a 90-degree rotation. A step stop or shoulder 225 is present on at least one of the at least two articulating transverse walls or protrusions 224 of the first housing portion 202a to engage the distal end 218 of the needle hub 216 and facilitate secure mounting of the needle unit 208 in either the first or second orientation. The flange 222 of the needle unit 208 has frictional engagement with opposing surfaces of at least two adjoining transverse walls or protrusions 224 of each of the first and second housing portions 202a, 202b when received in the gap 228 therebetween, thus avoiding the need to use less desirable means such as adhesives, overmolding, etc., to securely engage the needle unit within the housing, as discussed above.

[0110] Continuing with reference to Figures 13(a) and (b), when the needle unit 208 is mounted in a first orientation (i.e., when the distal end 218 of the needle hub 216 is oriented with the pair of radially extending diametrically opposed flanges 222 extending directly into and out of the plane of the paper in Figure 13(a) - this is also referred to herein as the flanges being disposed in a "vertical" position, i.e., position V), the predetermined distance d2 that the first end 212 of the needle shaft 210 extends out from the second contact surface 234 is a first predetermined distance d2a. As best shown in Figure 13(b), when the needle unit 208 is mounted in a second orientation (i.e., when the distal end 218 of the needle hub 216 is oriented with the pair of radially extending, diametrically opposed flanges 222 extending from side to side as shown in Figure 13(b) - also referred to herein as the flanges being disposed in a "horizontal" position, i.e., position H), the predetermined distance d2 that the first end 212 of the needle shaft 210 extends out from the second contact surface 234 is a second predetermined distance d2b. As illustrated in Figures 13(a) and 13(b), the first predetermined distance d2a is different from the second predetermined distance d2b. Again, the above description refers to the first housing portion 202a, but given that the first housing portion 202a and the second housing portion 202b are of identical construction, it will be understood that the first housing portion 202a is interchangeable with the second housing portion 202b.

[0111] As noted above, FIG. 5 represents a simplified first housing portion 202a of needle adapter body 200 of assembly 201, discussed in more detail above. In the labeling of FIG. 5 and its description above, references to components / elements of needle adapter body 200 of assembly 201 are provided in parentheses. For the sake of brevity, this disclosure will not be repeated here. However, with reference to FIG. 5 and its accompanying description, as well as Table 1, it will be apparent to those skilled in the art that the assembly of the present application has a significant advantage in that it is able to account for and compensate for manufacturer variations in needle shafts.

[0112] 14(a)-(c), after engagement of needle unit 208 with first housing portion 202a (FIG. 14(a)), second housing portion 202b is then engaged with first housing portion 202a (FIG. 14(b)) to form needle adapter body 200 (FIG. 14(c)). As one skilled in the art will recognize, given that first housing portion 202a and second housing portion 202b are of identical configuration, it is equally possible for the needle unit to engage with second housing portion 202b in the same manner as shown with first housing portion 202a in FIGS. 14(a)-(c).

[0113] 12-14, first housing portion 202a and second housing portion 202b are configured to snap-fit engage with one another to form housing 202. This is accomplished by fasteners (i.e., snaps) 236 protruding from the inner surface of each of first housing portion 202a and second housing portion 202b, which are configured to engage with complementary slots 238 formed in the interior portions of the housing of each of first housing portion 202a and second housing portion 202b in a snap-fit engagement. Each of first housing portion 202a and second housing portion 202b also has complementary ribs 240a and 240b that further assist in the engagement of first housing portion 202a and second housing portion 202b to form housing 202. Thus, the snap-fit engagement of the first housing portion 202a and the second housing portion 202b to form the housing 202 is a simple and straightforward means for securing and joining these two components of the housing 202 together and does not require the use of adhesives or other means for joining these components.

[0114] 12-14, each of the first and second housing portions 202a, 202b further includes a plurality of protrusions 242 extending from the inner surface 226 of its distal end to form a needle guide 244 configured to hold the needle shaft 210 in place. In the embodiment shown, the plurality of protrusions includes at least two needle stabilizing protrusions 242 disposed on either side of the needle shaft 210 and offset from one another along the longitudinal axis of the needle shaft 210, each having an inclined surface that abuts the needle shaft. These features of the needle adapter stabilize the needle shaft and hold it in a fixed position upon assembly of the first and second housing portions 202a, 202b to form the housing 202.

[0115] Similar to the needle adapter 100 described above, the angle between the longitudinal axis of the needle shaft 210 and the tangent plane defined by the first contact surface 232 is approximately 90°. It will be understood by those skilled in the art that this angle can be varied (e.g., within the range of about 5° to about 175°, about 10° to about 170°, about 60° to about 120°, e.g., about 80° to about 100°) by adjusting the angle at which the at least two continuous transverse walls or protrusions 224 extend from the inner surface 226 of the first / second housing portion (202a / 202b) along with other support features (e.g., needle guide 244) and the positioning of the foot 231.

[0116] As described above, the needle adapter body 200 is movably attached to the foot 231 to allow movement of the needle adapter body 200 from a first position to a second position. In the embodiment shown in Figures 11(a)-(d) and 12, there is a locking mechanism to provide a locked mode and an unlocked mode, where the locked mode is a mode of assembly in which the needle adapter body 200 is prevented from moving axially toward the foot 231 even when an axial force greater than a predetermined static friction is exerted on the needle adapter body 200 against the foot 231, and the unlocked mode is a mode of assembly in which the needle adapter body 200 is allowed to move toward the foot 231 when an axial force greater than a predetermined static friction is exerted on the needle adapter body 200. 11(a)-(d) and 12 includes a detachable safety clip 264 configured to engage a portion of an outer surface 266 of the housing 202 to maintain the foot 231 and the needle adapter body 200 spaced apart and prevent axial movement of the needle adapter body 200 toward the foot 231. The detachable safety clip 264 is formed from a resilient material (e.g., medical-grade plastic) and has a first leg 268 and a second leg 270 extending from a handle or grip 272, the first leg 268 and the second leg 270 defining a generally C-shape for engaging the outer surface 266 of the housing 202. Other alternative locking mechanisms are known in the art, such as that disclosed in WO2017 / 168015(A1), where, for example, the assembly can be unlocked when the foot is rotated relative to the needle adapter body about its longitudinal axis, resulting in an "unlocked" assembly, thus allowing the needle adapter body to move towards the foot.

[0117] As also mentioned above, the assembly further includes friction means for preventing movement of the needle adapter body 200 relative to the foot 231 when the needle adapter body 200 is in the first position until a predetermined static friction force is overcome, and for causing or allowing rapid acceleration of the needle adapter body 200 toward the foot 231 to increase the speed of the needle shaft 210 to increase the chance of skin penetration. The predetermined static friction force can be a value in the range of about 1.0 to about 20.0 Newtons, or about 1.5 to about 15 Newtons, or about 2.0 to about 1.0 Newtons, or about 5.0 to about 7.5 Newtons, and preferably the static friction force is at least about 2.0 Newtons.

[0118] In the embodiment shown in FIG. 12 , the friction means includes at least two protrusions 274 extending from the inner surface 276 of the proximal end 278 of the foot 231 in contact with at least two corresponding grooves 280 located on the outer surface 266 of the distal end 206 of the housing 202 of the needle adapter body 200; the radial dimension rd1 defined by the at least two protrusions 274 prior to assembly of the needle adapter body 200 and the foot 231 (see FIG. 15 ) is smaller than the radial dimension rd2 defined by the at least two corresponding grooves 280 (see FIGS. 17( a)-(b) ), and static friction is provided by radial clamping, as described in more detail below. The at least two corresponding grooves 280 are oriented generally parallel to the longitudinal axis of the housing 202.

[0119] It will be appreciated that the first friction means may equally include at least two protrusions extending from the outer surface of the body in contact with at least two corresponding grooves located on the inner surface of the foot, the radial dimension defined by the at least two protrusions prior to assembly of the body and foot being greater than the radial dimension defined by the grooves, and static friction being provided by radial clamping.

[0120] Figure 15 illustrates a perspective view of needle adapter body 200 and foot 231, clearly showing at least two protrusions 274 extending from inner surface 276 of proximal end 278 of foot 231 and one of at least two corresponding grooves 280 located on outer surface 266 of distal end 206 of housing 202 of needle adapter body 200. Figure 16 provides an enlarged perspective view of needle adapter body 200 to better illustrate the contours of groove 280.

[0121] 16 , at least two corresponding grooves 280 (one shown) are configured to prevent disengagement of foot 231 from needle adapter body 200 by limiting movement of foot 231 away from needle adapter body 200 following engagement of at least two protrusions 274 extending from inner surface 276 of proximal end 278 of foot 231 with at least two corresponding grooves 280. Groove portion 280a of each of at least two corresponding grooves 280 is slightly angled toward the center of needle adapter body 200 to facilitate initial engagement of at least two protrusions 274 with at least two corresponding grooves 280. However, it can be seen that once the at least two protrusions 274 engage the at least two corresponding grooves 280 and move toward the distal end 206 of the housing 202 until they reach groove portion 280b of each of the at least two corresponding grooves 280, movement of the foot 231 away from the needle adapter body 200 is limited by the ridge 281 (which projects upward at an approximately 90-degree angle from groove portion 280b) formed between groove portion 280b and groove portion 280a. At this point, static friction is provided by the radial clamping, as described above. When the locking mechanism is disengaged and the predetermined static friction force is overcome, i.e., when an axial force greater than the predetermined static friction force on the feet is exerted on the needle adapter body, the at least two protrusions 274 move toward groove portion 280c of each of the at least two corresponding grooves 280, and the friction between the surfaces undergoes a rapid decrease and / or drops to zero. This causes or allows for a rapid acceleration of the needle adapter body 200 towards the foot 231 to increase the velocity of the needle shaft 210 to increase the likelihood of skin penetration.

[0122] As shown in FIGS. 15 and 16 , the assembly further includes at least two deactivation grooves 282 located on the outer surface 266 of the distal end 206 of the housing 202 of the needle adapter body 100, each of the at least two deactivation grooves 282 being angled at an angle theta (θ) (about 25° to about 65°) relative to the longitudinal axis of the housing 202 such that axial movement of the foot 231 away from the needle adapter body 200 and rotation of the foot 231 relative to the needle adapter body 200 engages the at least two protrusions 274 with the at least two deactivation grooves 282 (one shown). 231), and each of the at least two deactivation grooves 282 includes a recess 284 complementary to the shape of each of the at least two protrusions 274 for securely engaging each of the at least two protrusions 274 so that the needle adapter body 200 is held in a fixed, deactivated position relative to the foot 231, and the first end 212 of the needle shaft 210 does not extend beyond the first contact surface 232 when the needle adapter body 200 is in the fixed, deactivated position relative to the foot 231.

[0123] Figure 17(a) illustrates one embodiment of assembly 201 in a perspective view (top) and a cross-sectional view (bottom) when the safety clip 264 is removed and the needle adapter body 200 is in a first position (i.e., ready for injection). Figure 17(b) illustrates assembly 201 in a perspective view (top) and a cross-sectional view (bottom, showing the subject's skin 250) when the safety clip 264 is removed and the needle adapter body 200 is in a second position (i.e., the needle penetrates the skin). Figure 17(c) illustrates assembly 201 in a perspective view (top) and a cross-sectional view (bottom) when the needle adapter body 200 is held in a fixed, deactivated position relative to the foot 231 (with axial movement of the foot 231 away from the needle adapter body 200 and rotation of the foot 231 relative to the needle adapter body 200 from the second position).

[0124] As shown in Figures 17(a)-(c), movement of the device from the first position to the second position causes or allows a rapid acceleration of the needle adapter body 200 toward the foot 231, causing the needle stabilizing projection 235 to pass through the opening 286 formed by the inner surface 288 of the foot 231 as the needle stabilizing projection 235 accelerates toward the skin 250.

[0125] As noted above, features of the needle adapter body 200 of the assembly 201 can account for and compensate for manufacturer variations in needle shafts by having the ability to mount the needle unit 208 in two different orientations within the housing 202. If further adjustment of the predetermined distance d2 that the first end 212 of the needle shaft 210 extends from the second contact surface 234 is required, this can be done during assembly of the device. Thus, a method for assembling the assembly includes obtaining foot 231, obtaining first and second housing portions 202a, 202b that form housing 202 of needle adapter body 200, obtaining needle unit 208, obtaining detachable safety clip 264, measuring the length of needle shaft 210, determining whether needle unit 208 should be attached in a first orientation or a second orientation based on the length of needle shaft 210, and optionally determining a preselected portion of the distal end of each of first and second housing portions 202a, 202b based on the length of needle shaft 210 and whether needle unit 208 should be attached in the first orientation or the second orientation. p2; attaching needle unit 208 to one of first housing portion 202a and second housing portion 202b in a first orientation or a second orientation by inserting at least a portion of one or both of pair of radially extending diametrically opposed flanges 222 of needle unit 208 into gap 228 formed between at least two adjoining transverse walls or protrusions 224; engaging first housing portion 202a and second housing portion 202b with one another to form housing 202 of needle adapter body 200; engaging detachable safety clip 264, if present, with a portion of outer surface 266 of housing 202; and engaging foot 231 with needle adapter body 200.Engaging the foot 231 with the needle adapter body 200 includes engaging at least two protrusions 274 extending from an inner surface 276 of the proximal end 278 of the foot 231 with at least two corresponding grooves 280 located on an outer surface 266 of the distal end 206 of the housing 202 of the needle adapter body 200. The preselected portion p2 of the distal end of each of the first and second housing portions 202a and 202b can be removed from the needle stabilizing protrusions 235 in a manner similar to that shown in FIG. 6 with respect to the needle adapter 100 described above. Removing the preselected portion p2 of the distal end of each of the first and second housing portions 202a and 202b can include cutting the preselected portion p2 of the distal end of each of the first and second housing portions 202a and 202b, such as by laser cutting.

[0126] The assembly process can be further automated so that devices can be assembled using vision / imaging systems ("machine vision") on automated assembly lines (e.g., based on CCD cameras) incorporating "pick-and-place" robotic technology. The assembly process can proceed as follows:

[0127] 1. Pre-fabricated Components: Housing shell—i.e., first and second housing portions 202a and 202b (two injection molded), safety clip 264 (injection molded), foot 231 (injection molded), needle unit 208 (preferably obtained from a Food and Drug Administration (FDA) approved source)

[0128] 2. Feeding components into the system (manual or (semi)automated): in feeders (e.g. injection molded components), in trays or racks (e.g. for needle units)

[0129] Steps 3 or 4 below can be performed in parallel with each other or in random order.

[0130] 3. The imaging system measures the exact length of the needle shaft 112 (eg, to an accuracy of 0.005 mm).

[0131] 4. Two housing shells (202a and 202b) are prepared / supplied to the automation system.

[0132] Step 5 is optional

[0133] 5. The needle stabilizing projections 235 on both housing shells 202a and 202b can be laser machined to improve the final needle shaft length for skin penetration).

[0134] 6. The needle is placed in one housing shell (202a), for example a horizontal wing, or for example a vertical wing, to compensate for the length deviation from step 3.

[0135] 7. A second (eg, identical) housing shell (202b) is (eg, automatically) attached (eg, snapped on).

[0136] Step 8 is optional / quality related

[0137] 8. Perform (imaging) measurement of remaining (penetration) length of needle shaft.

[0138] 9. Safety clip 264 is installed

[0139] 10. The foot 231 is installed.

[0140] FIG. 18(a) illustrates a proposed automated assembly line for preparing assembly 201 using machine vision and pick-and-place robotics techniques. "Housing 1" and "Housing 2" refer to the first and second housing portions 202a and 202b, "Needle" refers to needle unit 208, "Housing Attachment" refers to attaching needle unit 208 to one of the first and second housing portions 202a / 202b, "Pull Pin" refers to safety clip 264, and "Foot" refers to foot 231. Various elements are placed on a manufacturing carrier that moves along the assembly line via a conveyor belt. FIG. 18(b) illustrates the configuration of the manufacturing carrier at each stage of assembly. Components can be held in the carrier via slot engagement, which may be built in during their injection molding, and / or can be held in place via light vacuum or other means known to those skilled in the art.

[0141] As one skilled in the art will appreciate, it would be highly convenient to be able to manufacture assembly 201 from injection molded, pre-fabricated components that can be assembled via snap-fit engagement (as opposed to the use of adhesives or other attachment methods). Additionally, the ability to automate the manufacture of assembly 201 significantly reduces production costs, although it is certainly possible to manufacture assembly 201 manually.

[0142] A method of administering a fluid to a subject via injection using assembly 201 includes: (a) obtaining assembly 201, wherein needle adapter body 200 is in a first position; (b) obtaining a syringe 246 or other administration device, wherein the other administration device includes a dispensing tip similar in size and shape to a syringe tip, wherein syringe 246 or other administration device is filled with a fluid to be administered to the subject; (c) inserting tip 248 of syringe 246 or other administration device into channel 230 disposed in proximal end 204 of needle adapter housing 202 to engage the tip with needle hub 216; (d) engaging first contact surface 232 of foot 231 with the skin of the subject; and (e) pushing housing 202 of needle adapter body 200 axially toward foot 231 to move needle adapter body 200 from the first position to a second position. (f) discharging fluid from the syringe 246 or other administration device through the needle shaft 210 into the subject; and (g) pulling the housing 202 of the needle adapter body 200 axially away from the needle adapter body 200 and rotating the foot 231 relative to the needle adapter body 200 to engage the at least two protrusions 274 with the at least two deactivation grooves 284, and fixingly engaging each of the at least two protrusions 274 with the recesses 284 of each of the at least two deactivation grooves 282, such that the needle adapter body 200 is held in a fixed, deactivated position relative to the foot 231, the method further comprising removing the safety clip 264 from the outer surface 266 of the housing 202 after step (c) and before step (d), or after step (d) and before step (e). As noted above, other administration devices may include multi-chambered pre-filled containers (e.g., dual chambers for lyophilized material and diluent) having means for mixing the components of the chambers and means for expelling them from the administration device (e.g., by a plunger, etc.).

[0143] 19 illustrates a series of steps that may be used in administering a fluid to a subject via injection using assembly 201. As noted above, assembly 201 described herein is particularly well-suited for single use.

[0144] 20(a) and (b) show simplified cross-sectional views of one embodiment of assembly 201 engaged with syringe 246, thus forming an injection device 249 for administering a fluid to a subject via injection. As can be seen in FIGS. 20(a) and (b), no locking mechanism is present and needle adapter body 200 is in the second position (shown in FIG. 20(b)) when needle shaft 210 penetrates skin 250. FIG. 20(c) illustrates a perspective view of injection device 249 shown in FIGS. 20(a) and (b).

[0145] While the present invention has been described with reference to preferred embodiments, it should be understood that modifications and variations can be employed without departing from the spirit and scope of the invention, as will be readily apparent to those skilled in the art. Such modifications and variations are deemed to be within the purview and scope of the invention and the appended claims.

Claims

1. 1. A needle adapter for forming an injection device for administering a fluid to a subject, comprising: a housing formed from a first housing portion and a second housing portion, the housing having a proximal end and a distal end; a needle unit fixedly mounted within the housing, the needle unit comprising: a needle shaft including a first end for penetrating the skin of the subject and a second end connected to a needle hub; a needle unit, wherein the needle hub includes a distal end connected to the second end of the needle shaft and a proximal end including a pair of diametrically opposed radially extending flanges; each of the first and second housing portions including at least two articulating transverse walls or projections extending from an inner surface thereof, the at least two articulating transverse walls or projections defining a gap therebetween for receiving at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit for fixedly mounting the needle unit within the housing; the proximal end of the housing, together with the at least two adjoining transverse walls or protrusions of each of the first and second housing portions, defines a channel for receiving a syringe tip for engagement with the needle hub; a needle adapter, wherein the distal end of the housing includes a first contact surface adapted to be placed on the skin of the subject and a second contact surface, and the first end of the needle shaft extends outward from the second contact surface a predetermined distance to limit the penetration depth of the needle shaft.

2. the gap formed by the at least two contiguous transverse walls or protrusions of each of the first and second housing portions is configured to receive the at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit in one of a first and a second orientation of attachment of the needle unit; the predetermined distance that the first end of the needle shaft extends out from the second contact surface is a first predetermined distance when the needle unit is mounted in the first orientation; the predetermined distance that the first end of the needle shaft extends out from the second contact surface is a second predetermined distance when the needle unit is mounted in the second orientation; The needle adapter of claim 1 , wherein the first predetermined distance is different from the second predetermined distance.

3. The following features (a) to (g): (a) the at least a portion of one or both of the pair of radially extending, diametrically opposed flanges of the needle unit when received in the gap between the first and second housing portions has frictional engagement with opposing surfaces of the at least two articulating transverse walls or protrusions of each of the first and second housing portions; (b) the first housing portion and the second housing portion are configured to snap-fit engage with one another to form the housing; (c) each of the first and second housing portions further includes a plurality of protrusions extending from the inner surface of the distal end of each of the first and second housing portions to form a needle guide configured to hold the needle shaft in place; (d) the first contact surface is disposed along a periphery of the distal end of the housing, and the second contact surface is disposed substantially centrally at the distal end of the housing. (e) the first housing portion and the second housing portion are of at least substantially similar or identical construction; (f) the housing is generally cylindrical in shape; (g) each of the first housing portion and the second housing portion is generally semi-cylindrical in shape; 3. The needle adapter of claim 1 or 2, further comprising one or more of:

4. A needle adapter as described in claim 3, wherein the plurality of protrusions include at least two needle stabilizing protrusions arranged on either side of the needle shaft and offset from each other along the longitudinal axis of the needle shaft, each of the at least two needle stabilizing protrusions having an inclined surface abutting the needle shaft.

5. 1. An assembly for forming an injection device for administering a fluid to a subject, comprising: a foot including a first contact surface adapted to be placed on the skin of the subject, the foot having a tubular shape for receiving a needle adapter body; A needle adapter body, a housing formed from a first housing portion and a second housing portion, the housing having a proximal end and a distal end; a needle unit fixedly mounted within the housing, the needle unit comprising: a needle shaft including a first end for penetrating the skin of the subject and a second end connected to a needle hub; the needle hub including a distal end connected to the second end of the needle shaft and a proximal end including a pair of diametrically opposed radially extending flanges; each of the first and second housing portions including at least two articulating transverse walls or projections extending from an inner surface thereof, the at least two articulating transverse walls or projections defining a gap therebetween for receiving at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit for fixedly mounting the needle unit within the housing; the proximal end of the housing, together with the at least two adjoining transverse walls or protrusions of each of the first and second housing portions, defines a channel for receiving a syringe tip for engagement with the needle hub; a needle adapter body, the distal end of the housing including a second contact surface, the first end of the needle shaft extending from the second contact surface a predetermined distance to limit the penetration depth of the needle shaft; the needle adapter body is movably attached to the foot to allow movement of the needle adapter body from a first position to a second position; the needle shaft is in a retracted position such that the first end of the needle shaft does not extend beyond the first contact surface when the needle adapter body is in the first position; when the needle adapter body is in the second position, the first end of the needle shaft extends beyond the first contact surface and the predetermined distance from the second contact surface to limit the penetration depth of the needle shaft; The assembly further includes friction means for preventing movement of the needle adapter body relative to the foot when the needle adapter body is in the first position until a predetermined static friction force is overcome, and for causing or allowing rapid acceleration of the needle adapter body toward the foot to increase the speed of the needle shaft to increase the chance of penetration of the skin.

6. the gap formed by the at least two contiguous transverse walls or protrusions of each of the first and second housing portions is configured to receive the at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit in one of a first and a second orientation of attachment of the needle unit; the predetermined distance that the first end of the needle shaft extends out from the second contact surface is a first predetermined distance when the needle unit is mounted in the first orientation; the predetermined distance that the first end of the needle shaft extends out from the second contact surface is a second predetermined distance when the needle unit is mounted in the second orientation; The assembly of claim 5 , wherein the first predetermined distance is different from the second predetermined distance.

7. The following features (a) to (g): (a) the at least a portion of one or both of the pair of radially extending, diametrically opposed flanges of the needle unit when received in the gap between the first and second housing portions has frictional engagement with opposing surfaces of the at least two articulating transverse walls or protrusions of each of the first and second housing portions; (b) the first housing portion and the second housing portion are configured to snap-fit engage with one another to form the housing; (c) each of the first and second housing portions further includes a plurality of protrusions extending from the inner surface of the distal end of each of the first and second housing portions to form a needle guide configured to hold the needle shaft in place; (d) the first contact surface is disposed along a periphery of the distal end of the foot, and the second contact surface is disposed substantially centrally at the distal end of the housing. (e) the first housing portion and the second housing portion are of at least substantially similar or identical construction; (f) the housing is generally cylindrical in shape; (g) each of the first housing portion and the second housing portion is generally semi-cylindrical in shape; 7. The assembly of claim 5 or 6, further comprising one or more of:

8. An assembly as described in claim 7, wherein the plurality of protrusions include at least two needle stabilizing protrusions arranged on either side of the needle shaft and offset from each other along the longitudinal axis of the needle shaft, each of the at least two needle stabilizing protrusions having an inclined surface abutting the needle shaft.

9. 7. The assembly of claim 5, wherein the friction means includes at least two protrusions extending from an inner surface of the proximal end of the foot in contact with at least two corresponding grooves located on the outer surface of the distal end of the housing of the needle adapter body, the radial dimension defined by the at least two protrusions prior to assembly of the needle adapter body and the foot being smaller than the radial dimension defined by the at least two corresponding grooves, and the static friction force is provided by radial clamping.

10. The following features (a) to (c): (a) the at least two corresponding grooves are configured to prevent disengagement of the foot from the needle adapter body by limiting movement of the foot away from the needle adapter body following engagement of the at least two protrusions extending from the inner surface of the proximal end of the foot with the at least two corresponding grooves; (b) the at least two corresponding grooves are oriented generally parallel to a longitudinal axis of the housing; (c) the assembly further includes at least two deactivation grooves located on the outer surface of the distal end of the housing of the needle adapter body; each of the at least two deactivation grooves intersects one of the at least two corresponding grooves at an angle relative to the longitudinal axis of the housing such that axial movement of the foot away from the needle adapter body and rotation of the foot relative to the needle adapter body engages the at least two protrusions with the at least two deactivation grooves; each of the at least two deactivation grooves includes a recess complementary in shape to each of the at least two protrusions for fixedly engaging with each of the at least two protrusions such that the needle adapter body is held in a fixed, deactivated position relative to the foot; the first end of the needle shaft does not extend beyond the first contact surface when the needle adapter body is in the locked, inactivated position relative to the foot. The assembly of claim 9 , further comprising one or more of:

11. further comprising a locking mechanism for providing a locked mode and an unlocked mode of the injection device; the locked mode is a mode of the assembly in which the needle adapter body is prevented from moving axially toward the foot even when an axial force greater than the predetermined static friction force is exerted on the needle adapter body against the foot, 7. An assembly as described in claim 5 or 6, wherein the unlocked mode is a mode of the assembly in which the needle adapter body is allowed to move axially toward the foot when an axial force greater than the predetermined static friction force against the foot is exerted on the needle adapter body.

12. An assembly as described in claim 11, wherein the locking mechanism includes a removable safety clip configured to engage a portion of the outer surface of the housing to maintain the foot and needle adapter body spaced apart from each other and prevent the needle adapter body from moving axially toward the foot.

13. 10. A method for assembling the needle adapter of claim 1, comprising: obtaining the first housing portion and the second housing portion; obtaining the needle unit; attaching the needle unit to one of the first and second housing portions by inserting the at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit into the gap formed between the at least two adjoining transverse walls or projections; and engaging the first housing portion and the second housing portion to form the housing.

14. The method of claim 13, further comprising measuring the length of the needle shaft and removing a preselected portion of the distal end of each of the first housing portion and the second housing portion based on the length of the needle shaft.

15. 3. A method for assembling the needle adapter of claim 2, comprising: obtaining the first housing portion and the second housing portion; obtaining the needle unit; measuring the length of the needle shaft; determining whether the needle unit should be mounted in the first orientation or the second orientation based on the length of the needle shaft; attaching the needle unit to one of the first and second housing portions in the first or second orientation by inserting the at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit into the gap formed between the at least two adjoining transverse walls or protrusions; and engaging the first housing portion and the second housing portion to form the housing.

16. The method of claim 15, further comprising removing a preselected portion of the distal end of each of the first housing portion and the second housing portion based on the length of the needle shaft and based on whether the needle unit should be mounted in the first orientation or the second orientation.

17. 17. The method of claim 14 or 16, wherein removing the preselected portion of the distal end of each of the first and second housing portions comprises cutting the preselected portion of the distal end of each of the first and second housing portions.

18. 20. The method of claim 17, wherein the method is automated.

19. 6. A method for assembling the assembly of claim 5, comprising the steps of: obtaining the foot; obtaining the first housing portion and the second housing portion forming the housing of the needle adapter body; obtaining the needle unit; attaching the needle unit to one of the first and second housing portions by inserting the at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit into the gap formed between the at least two adjoining transverse walls or projections; engaging the first housing portion and the second housing portion to form the housing of the needle adapter body; and engaging the foot with the needle adapter body.

20. The following features (a) to (b): (a) the assembly further includes a locking mechanism, the locking mechanism including a removable safety clip configured to engage a portion of the exterior surface of the housing to maintain the foot and needle adapter body spaced apart and prevent axial movement of the needle adapter body toward the foot, the method comprising: obtaining the detachable safety clip; and engaging the removable safety clip with the portion of the outer surface of the housing after engaging the first and second housing portions with one another. (b) prior to attaching the needle unit, measuring a length of the needle shaft and removing a preselected portion of the distal end of each of the first and second housing portions based on the length of the needle shaft; 20. The method of claim 19, further comprising one or more of:

21. 7. A method for assembling the assembly of claim 6, comprising the steps of: obtaining the foot; obtaining the first housing portion and the second housing portion forming the housing of the needle adapter body; obtaining the needle unit; measuring the length of the needle shaft; determining whether the needle unit should be mounted in the first orientation or the second orientation based on the length of the needle shaft; attaching the needle unit to one of the first and second housing portions in the first or second orientation by inserting the at least a portion of one or both of the pair of radially extending diametrically opposed flanges of the needle unit into the gap formed between the at least two adjoining transverse walls or protrusions; engaging the first housing portion and the second housing portion to form the housing of the needle adapter body; and engaging the foot with the needle adapter body.

22. The following features (a) to (b): (a) the assembly further includes a locking mechanism, the locking mechanism including a removable safety clip configured to engage a portion of the exterior surface of the housing to maintain the foot and needle adapter body spaced apart and prevent axial movement of the needle adapter body toward the foot, the method comprising: obtaining the detachable safety clip; and engaging the removable safety clip with the portion of the outer surface of the housing after engaging the first and second housing portions with one another. (b) prior to attaching the needle unit, removing a preselected portion of the distal end of each of the first and second housing portions based on the length of the needle shaft and whether the needle unit is to be attached in the first orientation or the second orientation; 22. The method of claim 21, further comprising one or more of:

23. 23. The method of claim 20 or 22, wherein removing the preselected portion of the distal end of each of the first and second housing portions comprises cutting the preselected portion of the distal end of each of the first and second housing portions.

24. 24. The method of claim 23, wherein the method is automated.

25. A kit comprising: The needle adapter according to claim 1 or 2; a syringe or other administration device, the other administration device including a dispensing tip similar in size and shape to the syringe tip.

26. The following features (a) to (e): (a) the syringe or other administration device is filled with the fluid to be administered to the subject; (b) the kit further comprises a vial containing the fluid to be administered to the subject; (c) the kit further includes a detachable needle unit or other means for extracting the fluid from the vial into the syringe or other administration device, the detachable needle unit being detachable to allow a tip of the syringe or other administration device to be inserted into the channel of the housing; (d) the kit further includes a safety holder having an open end for receiving at least the distal end of the housing of the needle adapter and a closed end, the closed end including opposed wings for stabilizing the safety holder on a horizontal surface. (e) the kit further comprises instructions for use.

26. The kit of claim 25, further comprising one or more of:

27. A kit comprising: an assembly according to claim 5 or 6; a syringe or other administration device, the other administration device including a dispensing tip similar in size and shape to the syringe tip.

28. The following features (a) to (d): (a) the syringe or other administration device is filled with the fluid to be administered to the subject; (b) the kit further comprises a vial containing the fluid to be administered to the subject; (c) the kit further includes a detachable needle unit or other means for extracting the fluid from the vial into the syringe or other administration device, the detachable needle unit being detachable to allow a tip of the syringe or other administration device to be inserted into the channel of the housing; (d) the kit further comprises instructions for use; 28. The kit of claim 27, further comprising one or more of:

29. 1. An injection device comprising: The needle adapter according to claim 1 or 2; an injection device comprising: a syringe or other administration device, said other administration device comprising a dispensing tip similar in size and shape to a syringe tip; 30. The injection device of claim 29, wherein the syringe or other administration device is filled with a fluid to be administered to a subject.

31. 1. An injection device comprising: an assembly according to claim 5 or 6; an injection device comprising: a syringe or other administration device, said other administration device comprising a dispensing tip similar in size and shape to a syringe tip; 32. The injection device of claim 31, wherein the syringe or other administration device is filled with a fluid to be administered to a subject.

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