Needle-free injection system

Abstract

A gas-actuated needle-free injector is provided. The gas-actuated needle-free injector includes a gas spring in communication with a piston. A vaccine dispensing chamber is configured to receive one or more vaccines or components thereof. A ball screw is coaxial with the gas spring and the vaccine dispensing chamber and configured to receive at least a portion of the piston. The ball screw is configured to move the piston between a first position and a second position. Related systems and methods are also provided.

Description

[Technical Field]

[0001] The present disclosure relates to needle-free injection systems, and more particularly to needle-free injection systems that include an actuated gas spring for pressure regulation, an axial push-back mechanism, and / or an electro-hydraulic trigger. [Background technology]

[0002] This section provides background information related to the present disclosure that is not necessarily prior art.

[0003] Needle-equipped syringes have traditionally been used to inject medications and other substances for various animal and human health applications. However, these devices have significant drawbacks, including an increased risk of disease transmission between injection recipients and breakage and possible tissue damage at the injection site, which raises serious health concerns and leads to significant profit losses for meat producers. Needle-free injection systems address many of these concerns. Mechanical springs are often used to provide a compact energy storage mechanism for needle-free injection. However, force adjustments are often required to vary the injection depth, for example, from day-old piglets to adult sows. Such adjustments are often impractical with mechanical springs. One common alternative involves pneumatically driven systems. However, these systems often require the injection system to be connected to a compressor, which impacts ergonomics. Gas springs are an alternative to mechanical and pneumatically driven systems and are often considered the lowest mass spring for needle-free injection. However, gas springs often experience undesirable drift with temperature (e.g., fluctuations in ambient temperature and / or cooling after gas compression during priming). Furthermore, both mechanical and gas springs often require a mechanical frame to prevent accelerated twisting and seal wear. Such mechanical frames can undesirably increase the overall mass of the needle-free injection system. Similarly, mechanical trigger mechanisms are often used to release gas or mechanical springs. However, such mechanisms often experience associated wear and lifespan issues due to the large forces applied. One common alternative involves mechanically operated hydraulic triggers, which require a reduction in pressure in the hydraulic hose to reset, limiting their ability to accurately deliver small doses. Therefore, it is desirable to develop devices and methods to address each of these concerns.

[0004] The drawings described herein are for the purpose of illustrating selected embodiments only, not all possible implementations, and are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a perspective cross-sectional view of an example of a gas-actuated needle-free injector with a fully extended gas spring, according to various aspects of the present disclosure. [Figure 2] FIG. 10 is another perspective cross-sectional view of an example gas-actuated needle-free injector with the gas spring fully extended, according to various aspects of the present disclosure. [Figure 3] FIG. 1 is a close-up view of a receiving port of a gas-actuated needle-free syringe according to various aspects of the present disclosure. [Figure 4] FIG. 1 is a cross-sectional view of the nozzle end of an example vaccine dispensing chamber of a gas-actuated needle-free injector according to various aspects of the present disclosure. [Figure 5] FIG. 10 is another cross-sectional view of the nozzle end of the vaccine dispensing chamber of an example gas-actuated needle-free injector with the solenoid actuator in the "off" position, according to various aspects of the present disclosure. [Figure 6] FIG. 10 is another cross-sectional view of the nozzle end of the vaccine dispensing chamber of an example gas-actuated needle-free injector with the solenoid actuator in the "on" position, according to various aspects of the present disclosure. [Figure 7] FIG. 1 is a cross-sectional view of an example of a gas-actuated needle-free injector according to various aspects of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram of a vaccine administration chamber of an example gas-actuated needle-free injector, according to various aspects of the present disclosure. [Figure 9] FIG. 9 is an enlarged view of the receiving port of the vaccine administration chamber of FIG. 8. [Figure 10] FIG. 1 is a close-up view of a motor belt system of a gas-actuated needle-free injector according to various aspects of the present disclosure. [Figure 11] FIG. 1 is a partial cross-sectional view of an example of a gas-actuated needle-free injector with a fully extended gas spring, according to various aspects of the present disclosure. [Figure 12]FIG. 13 is a partial cross-sectional view of an example of a gas-actuated needle-free injector in which a piston of a gas spring is pushed back by a ball screw, the action of which draws vaccine(s) and / or vaccine components into a vaccine dispensing chamber, according to various aspects of the present disclosure. [Figure 13] FIG. 1 is a partial cross-sectional view of a portion of a gas-actuated needle-free injector in a loaded state, where the gas-actuated needle-free injector is ready to administer vaccine(s) and / or vaccine components, according to various aspects of the present disclosure. [Figure 14] FIG. 1 is a partial cross-sectional view of an example of a gas-actuated needle-free injector in which the hydraulic valve is in an open position to administer vaccine(s) and / or vaccine components, and administration continues until the piston reaches the end stop, according to various aspects of the present disclosure. [Figure 15] FIG. 1 is a partial cross-sectional view of an example of a gas-actuated needle-free injector with the piston of the gas spring in a fully extended position, according to various aspects of the present disclosure. [Figure 16] FIG. 1 is a partial cross-sectional view of an example of a gas-actuated needle-free injector with the piston of the gas spring in a retracted position, according to various aspects of the present disclosure. [Figure 17] FIG. 1 is a partial cross-sectional view of an example of a gas-actuated needle-free injector with the piston of the gas spring in a fully extended position, according to various aspects of the present disclosure. [Figure 18] FIG. 1 is a partial cross-sectional view of an example of a gas-actuated needle-free injector with the piston of the gas spring in a retracted position, according to various aspects of the present disclosure. [Figure 19] FIG. 10 is a schematic diagram of another example of a gas-actuated needle-free injector with a fully extended gas spring, according to various aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

[0007] Exemplary embodiments are described more fully hereinafter with reference to the accompanying drawings.

[0008] The exemplary embodiments are provided so that the present disclosure is detailed and will fully convey its scope to those skilled in the art. Numerous specific details are described, such as examples of specific components, devices, and methods, to provide a thorough understanding of the embodiments of the present disclosure. As will be apparent to those skilled in the art, the use of specific details is not necessary, and the exemplary embodiments may be embodied in many different forms, neither of which should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0009] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may be intended to include the plural forms unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and thus specify the presence of stated features, components, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, components, steps, operations, elements, components, and / or groups thereof. The steps, processes, and operations of methodologies described herein should not be construed as necessarily requiring performance in the particular order described or illustrated, unless specifically identified as such. It should be understood that additional or alternative steps may be employed.

[0010] When an element or layer is referred to as "on," "engaging with," "connected to," or "coupled to" another element or layer, it may be directly on, engaging with, connected to, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as "directly on," "directly engaging with," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other terms used to describe relationships between elements should be interpreted similarly (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0011] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections are not intended to be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as "first," "second," and other numerical terms, when used herein, do not imply an order or sequence unless clearly dictated by context. Thus, a first element, component, region, layer, or section described below could be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0012] Spatially relative terms such as "inside," "outside," "below," "below," "lower," "above," and the like may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s), as shown in the figures. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, an element described as "below" or "below" another element or feature would be oriented "above" the other element or feature. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be in other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein would be interpreted accordingly.

[0013] 1 and 2 are cross-sectional views of an example of a gas-actuated needle-free injector 100. The gas-actuated needle-free injector 100 includes a pneumatic energy storage element (e.g., gas spring 110) in communication with a dispensing chamber (e.g., vaccine dispensing chamber 150), which is a high-pressure chamber configured to receive a fluid, such as, for example, one or more vaccines and / or components for making a vaccine or multiple vaccines. For example, as shown, a piston 170 (e.g., a high-pressure piston) may connect the gas spring 110 and the vaccine dispensing chamber 150. A housing 120 may surround and support the gas spring 110 and the vaccine dispensing chamber 150. For example, the housing 120 may include a first end plate 122 parallel to a second end plate 124 and a plurality of rods (or dowels) 126 extending between and coupled to the first and second end plates 122, 124. The housing 120 may also include a support structure 128 coupled to one or more rods 126. As shown, the support structure 128 may include or function as a linear actuator, such as a ball screw actuator having a ball screw bearing 135. The support structure may further include a motor mount (not shown).

[0014] Ball screw bearing 135, vaccine dosing chamber 150, and gas spring 110 may be coaxial. For example, in certain variations, support structure 128 may be disposed at the interface between gas spring 110 and vaccine dosing chamber 150 to support and align gas spring 110 and vaccine dosing chamber 150. As shown, first end 111 of gas spring 110 may be coupled to first end plate 122, second end 112 of gas spring 110 may be coupled to support structure 128, and vaccine dosing chamber 150 may be coupled to second end plate 124 and extend through support structure 128 toward second end 112 of gas spring 110. As shown, in certain variations, support structure 128 may include one or more couplers 129 configured to connect to the second end of gas spring 112. In certain variations, vaccine dispensing chamber 150 may interface with or extend into second end 112 of gas spring 110. For example, support structure 128 may include a hollow drive nut 130 having a cavity 136 that receives piston 170 and defining a cavity 132 configured to receive ball screw 134 configured to move on vaccine dispensing chamber 150. Piston 170 may also be configured to move through one or more couplers 129 that connect support structure 128 and gas spring 112.

[0015] The vaccine dispensing chamber 150 communicates with a nozzle 180 extending from or through the second end plate 124. In certain variations, the nozzle 180 may be formed from a wear-resistant material such as stainless steel or ruby ​​and may be removable for cleaning and / or replacement. Furthermore, the nozzle may have a single injection orifice. By comparison, a spray nozzle typically has multiple small holes facing in various directions. A single injection orifice according to the present disclosure may have an inner diameter of about 200 micrometers (μm) or more to about 400 μm or less, and optionally about 300 μm in certain embodiments. In either case, the nozzle 180 can be contacted with a subject (e.g., a sow, a piglet) to administer one or more vaccines and / or components for making a vaccine or vaccines. For example, the injection orifice may be configured to generate a single coherent jet that penetrates the subject's tissue.

[0016] One or more sensors 140, such as optical switches, may be used to determine the position of piston 170. In some cases, for example, sensing element 145 may be coupled to piston 170 such that sensing element 145 interacts with sensor 140 to determine the position of piston 170.

[0017] The nozzle 180 includes one or more triggers 182 configured to initiate movement, moving the nozzle 180 (and the gas-actuated needle-free injector 100) from a closed position to an open position. The one or more triggers 182 may be configured to prevent the movement of air into the nozzle 180. For example, FIGS. 3-6 are cross-sectional views of the nozzle end of a gas-actuated needle-free injector 100, and as shown, the one or more triggers 182 may activate a solenoid actuator 300. Such a nozzle 180 may include an injection orifice 302, a valve spring 304, a plunger 306, a casing 308, a filter 310, and an electrical connection 312. FIG. 5 shows the solenoid actuator in the "off" position, which prevents dispersion of fluid from the injection orifice 302. FIG. 6 shows the solenoid actuator in the "on" position, which allows dispersion of fluid from the injection orifice 302.

[0018] 7, vaccine dispensing chamber 150 and nozzle 180 may be connected using a flexible hose 189. Flexible hose 189 may be connected to a wearable handset. In some cases, a pressure hydraulic hose may connect vaccine dispensing chamber 150 to a solenoid actuator 300.

[0019] Continuing with reference to FIG. 7 , according to one embodiment, gas spring 110 may be connected to dispensing chamber 150, which may be under high pressure. This link allows for tolerance in axial alignment of gas spring 110 and dispensing chamber 150, but may be arranged to "float" so that no gaps form because gas spring 110 is at a constant pressure against piston 170. Dispensing chamber 150 may be filled, and gas spring 110 may be pushed back by a ball screw actuator coaxial with dispensing chamber 150 and gas spring 110. Dispensing chamber 150 may be filled by a one-way inlet valve, and hydraulic trigger valve 160 is closed to prevent air from entering the nozzle. Returning the ball screw actuator to different positions allows for the delivered dose to be varied. When the system is primed, the ball screw actuator retracts, and the position is maintained by the pressure of the hydraulic fluid (or vaccine, as the case may be). To release the injection, an electrically or mechanically operated hydraulic trigger valve 160 is opened, which may be located in the wearable part or in the handpiece held by the operator. In some cases, the hydraulic trigger valve 160 may form the injection nozzle of the handpiece. The injection ends either when the piston 170 hits its end stop or when the hydraulic trigger valve is closed. The latter case allows for more accurate delivery of small doses as well as variable doses at a fixed priming position.

[0020] In some cases, the hydraulic trigger valve may be an electro-hydraulic trigger, which does not wear out and does not apply disproportionate forces to the main force generator. Additionally, more precise dose control can be achieved for small doses (e.g., microdoses) because the injection can be electrically shut off rather than having to depressurize a flexible hose. This is an advantage over machine-operated hydraulic triggers, which require pressure reduction in the hydraulic hose to reset, thus limiting the ability to accurately deliver small doses.

[0021] Vaccine dispensing chamber 150 may also include one or more one-way inlet (or receiving) ports (or openings) configured to receive one or more vaccines and / or components for making a vaccine. For example, as shown in FIGS. 1-4, vaccine dispensing chamber 150 may have receiving port 152 disposed near second end plate 124. Receiving port 152 may include a valve configured to communicate with a vaccine vial. For example, in certain variations, the valve may include multiple threads with or without an O-ring. In certain variations, the valve may be actuated at low pressure by depressing it from a higher (or top) position, but at high pressures (e.g., about 600 bar), it compresses down to a metal-on-metal seal. FIGS. 3 and 9 show close-up views of receiving port 152 in certain examples.

[0022] Moving piston 170 from a first, fully extended position to a second, retracted position can create a negative pressure to draw one or more vaccines and / or ingredients for making the vaccine or vaccines through receiving port 152. Moving piston 170 from the second, retracted position to the first, fully extended position (e.g., by releasing piston 170) can force one or more vaccines and / or ingredients for making the vaccine or vaccines through nozzle 180. In certain variations, movement of piston 170 can be controlled by a drive motor 190 coupled to and supported by support structure 128. For example, as best shown in FIG. 10 , drive motor 190 can be configured to move (e.g., rotate) a belt 192 configured to move (e.g., rotate) ball screw 134. Drive motor 190 can be powered by a battery (not shown) and controlled using a control system. For example, in various embodiments, the control system can be configured to initiate movement of the drive motor 190 to allow the piston 170 to move to various degrees, e.g., using a rotary contact, to vary the amount of vaccine injected.

[0023] 11-14 are partial cross-sectional views of the needle-free injector 100 illustrating the movement of the piston 170 to draw and inject a vaccine. For example, FIG. 11 (similar to FIGS. 1 and 2) illustrates a rest or starting position in which the gas spring 110, and more specifically the piston 170, is in a first, fully extended position. For comparison, FIG. 12 illustrates the piston 170 moving from the first, fully extended position to a second, retracted position. As shown, the negative pressure created by the piston 170 moving from the first position to the second position allows one or more vaccines and / or ingredients for making the vaccine or vaccines to enter through the receiving port 152. FIG. 13 illustrates the loaded state of the needle-free injector 100 in which one or more vaccines and / or ingredients for making the vaccine or vaccines have been drawn into the vaccine dispensing chamber 150 and are ready for administration to a subject. Figure 14 illustrates the movement of one or more valves (or triggers) 182 and the release (or administration) of one or more vaccines and / or ingredients for making a vaccine or vaccines upon opening of nozzle 180. By way of further illustration, Figures 15 and 16 are partial cross-sectional views showing piston 170 moving from a first fully extended position to a second retracted position, and Figures 17 and 18 are additional partial cross-sectional views showing ball screw 134 moving from a first fully extended position to a second retracted position.

[0024] 19 is a schematic diagram illustrating another example of a gas-actuated needle-free injector 200 having a first portion (or component) 210 and a second portion (or component) 250. The first portion 210 can be distinguished from the second portion 250 in that the first portion 210 is a portable or wearable component, while the second portion 250 is a handheld administration device (e.g., single nozzle 252A or dual nozzle 252B). The first portion 210 may include one or more gas-actuated components 292, 294 having a configuration similar to that of the gas-actuated needle-free injector 100 shown in FIGS. 1-18.

[0025] 19 , the first portion 210 may include one or more gas-powered high-pressure vaccine delivery units (e.g., gas springs 201, 202 defining a first sub-part or portion) in communication with a pressure regulating cylinder 203 (defining a second sub-part or portion) that allows the pressure within the gas springs 201, 202 to be adjusted. For example, in certain variations, the first portion 210 may include first and second gas-powered needle-free syringe springs 201, 202 disposed downstream of the pressure regulating cylinder 203. As shown, the first gas-powered needle-free syringe spring 201 may be disposed in parallel with the second gas-powered needle-free syringe spring 202. The one or more gas-powered needle-free syringe springs 201, 202 may be connected to the pressure regulating cylinder 203 using one or more connecting hoses or tubes 204, 205. For example, as shown, a first connecting hose 204 may connect a first gas-powered needle-free syringe spring 201 to a pressure adjustment cylinder 203, and a second connecting hose 205 may connect a second gas-powered needle-free syringe spring 202 to the pressure adjustment cylinder 203.

[0026] In certain variations, one or more connecting hoses 204, 205 may include one or more gate valves 206, 207. For example, as shown, first connecting hose 204 may include a first gate valve 206, and second connecting hose 205 may include a second gate valve 207. The first gate valve 206 may be located at any point along the first connecting hose 204. As shown, the first gate valve 206 may be located, by way of example only, approximately midway between the pressure regulating cylinder 203 and the first gas-operated needle-free syringe spring 201. Similarly, the second gate valve 207 may be located at any point along the second connecting hose 205. As shown, the second gate valve 206 may be located, by way of example only, approximately midway between the pressure regulating cylinder 203 and the second gas-operated needle-free syringe spring 202. The first gate valve 206 may be located independently of the second gate valve 207. In either case, one or more gate valves 206, 207 may be closed at certain times, such as during the firing stroke of the pressure regulating cylinder 203, to restrict or prevent unwanted gas flow.

[0027] First portion 210 may also include one or more vaccine dispensing chambers 211, 212 (defining a third sub-component or portion). For example, first vaccine dispensing chamber 211 may be in communication with first gas-powered needle-free injector spring 201, and second vaccine dispensing chamber 212 may be in communication with second gas-powered needle-free injector spring 202. As shown, each of gas-powered needle-free injector springs 201, 202 includes a volume receiving portion 201A, 202A and a plunger or piston 201B, 202B that moves relative to volume receiving portion 201A, 202A. Pistons 201B, 202B may be configured to move between a first position and a second position. In certain variations, as described above, motors 213A, 213B can be in communication with pistons 201B, 202B to assist in moving pistons 201B, 202B from a first extended position to a second retracted position. As shown, a portion of piston 201B, 202B extends into receiving cavity 211A, 212A of one of one or more vaccine dispensing chambers 211, 212, and movement of piston 201B, 202B can depend on pressure within volume receiving portion 201A, 202A and / or pressure applied to piston 201B, 202B. In each variation, the second and third sub-components can be constructed separately to allow for greater manufacturing flexibility.

[0028] First section 210 may be connected to second section 250 via one or more connecting tubes or hoses 254, 255. For example, as shown, third connecting tube 254 may connect first vaccine dispensing chamber 211 to first inlet port 256A of dual nozzle 252B, and fourth connecting tube 255 may connect second vaccine dispensing chamber 212 to second inlet port 256B of dual nozzle 252B. One or more connecting hoses 254, 255 may include one or more gate valves 260, 262. For example, as shown, third connecting hose 254 may include third gate valve 260, and fourth connecting hose 255 may include second gate valve 262. Third gate valve 260 may be located at any point along third connecting hose 254. As shown, third gate valve 260 may be located, by way of example only, approximately midway between first vaccine administration chamber 211 and first inlet port 256A of dual nozzle 252B. Similarly, fourth gate valve 262 may be located at any point along fourth connecting hose 255. According to some embodiments, gate valves 260, 262 may be located internal to dual nozzle device 252B such that they are located near nozzle 180.

[0029] As shown, fourth gate valve 262 may be located, by way of example only, approximately midway between second vaccine administration chamber 212 and second inlet port 256B of dual nozzle 252B. Third gate valve 260 may be located independently of fourth gate valve 262. According to some embodiments, because pressure is not regulated during the firing stroke of activated gas spring 203, connecting hoses 204, 205 (for air flow) may have a relatively small inner diameter compared to connecting hoses 254, 255 (for liquid flow, e.g., vaccine). For example, in certain variations, connecting hoses 254, 255 may each have an average inner diameter of about 1 millimeter or more to about 3 millimeters or less, and in certain embodiments, may optionally have an average inner diameter of about 2 millimeters. In some cases, connecting hoses 204, 205 may have the same or larger inner diameter compared to connecting hoses 254, 255.

[0030] Similar to the first and second gas-actuated needle-free injector springs 201, 202, the actuated gas spring 203 may include a plunger or piston 251 that moves relative to a volume-receiving portion 253. For example, the piston 251 may be configured to move between a first position and a second position. In certain variations, as described above, a motor 254 may be in communication with the piston 251 to assist in moving the piston from a first extended position to a second retracted position. As described further below, smaller movements of the actuated gas spring 203 may be used to compensate for temperature drift. For example, in certain variations, the actuated gas spring 203 may be used in combination with one or more pressure sensors (not shown) to ensure the firing force of the gas-actuated needle-free injector 200 is maintained during temperature drift. Conversely, larger movements of the actuated gas spring 203 may be used to vary the overall pressure, allowing the gas-actuated needle-free injector 200 to be used at different injection depths.

[0031] In some cases, it may be desirable to administer small injection volumes (e.g., microdoses) to a subject without a needle. However, the inventors have discovered that existing needleless systems are unable to accurately administer such small injection volumes due to pressure transients during the initial injection period. That is, such systems produce pressure oscillations that are large compared to the propagation time of pressure waves and take a certain amount of time to decay. The source of such oscillations has typically been found to be rigid tubes or hoses attached to the fluid delivery handpiece or nozzle, particularly at the junction between a rigid tube / hose and a flexible hose (e.g., hydraulic hose). In this regard, pressure waves in rigid tubes / hoses travel at a faster speed than pressure waves in flexible hydraulic hoses. The junction between the rigid and flexible hoses creates an impedance mismatch for wave propagation, resulting in reflections and standing waves.

[0032] Thus, according to some embodiments of the present disclosure, a flexible (e.g., elastic) hose 189, such as a flexible hydraulic hose, is in fluid communication with a fluid reservoir and is connected in close proximity to the injection orifice 302 of the nozzle 180. According to some embodiments, the flexible hose 189 may be connected within about 10 cm of the injection orifice 302. In some cases, the flexible hose 189 may be connected within about 2 cm of the injection orifice 302. By connecting the flexible hose 189 close to the injection orifice 302, the time scale of vibrations, and therefore the time scale of initial turbulence, is compressed. Such a system may be used to deliver injections of doses less than 0.5 ml accurately and at high injection rates.

[0033] According to some embodiments, a damping element, such as a viscoelastic material, can be incorporated near the nozzle to help dampen any high frequency vibrations. In some cases, an O-ring seal may be used, but to provide better damping functionality, a non-sealing viscoelastic component, such as an O-ring, may be used that does not function as a seal but instead acts as a volume compression damper.

[0034] The description of the foregoing embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, may be interchangeable and used in selected embodiments even if not specifically shown or described. The same may also be varied in many ways. Such variations should not be considered a departure from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. a gas spring in communication with the piston; a vaccine administration chamber configured to receive one or more vaccines or components thereof; a ball screw coaxial with the gas spring and the vaccine administration chamber, configured to receive at least a portion of the piston, and configured to move the piston between a first position and a second position.

2. The gas-operated needleless syringe comprises:

10. The gas-actuated needle-free injector of claim 1, further comprising a first nozzle configured to contact a subject and be in fluid communication with the vaccine administration chamber, the first nozzle comprising a first single injection orifice and configured to generate a single coherent jet comprising the one or more vaccines.

3. 3. The gas-actuated needle-free injector of claim 2, comprising a first portion comprising the gas spring, the vaccine administration chamber, and the ball screw, and a second portion comprising the first nozzle.

4. 4. The gas-actuated needle-free injector of claim 3, wherein the first portion is a wearable component and the second portion is a handheld administration device.

5. 5. The gas-actuated needle-free injector of claim 4, wherein the first portion and the second portion are connected by one or more connecting tubes.

6. 3. The gas-actuated needle-free injector of claim 2, wherein the gas spring is a first gas spring, the vaccine administration chamber is a first vaccine administration chamber, the ball screw is a first ball screw, and the gas-actuated needle-free injector further comprises a second gas spring, a second vaccine administration chamber, and a second ball screw, wherein the first gas spring, the first vaccine administration chamber, and the first ball screw define a first assembly in communication with the first single injection orifice, and the second gas spring, the second vaccine administration chamber, and the second ball screw define a second assembly.

7. 7. The gas-actuated needle-free injector of claim 6, further comprising a second nozzle configured to contact a subject and in fluid communication with the second vaccine administration chamber, the second nozzle comprising a second single injection orifice and configured to generate a single coherent jet comprising one or more vaccines, the second assembly being in communication with the second single injection orifice.

8. 8. The gas-actuated needle-free injector of claim 7, further comprising: a first connecting tube including one or more first valves connecting the first vaccine administration chamber and the first single injection orifice; and a second connecting tube including one or more second valves connecting the second vaccine administration chamber and the second single injection orifice.

9. 9. The gas-actuated needle-free injector of claim 8, wherein the first valve and the second valve are disposed within a handheld administration device.

10. 9. The gas-actuated needle-free injector of claim 8, wherein the first valve and the second valve are electrically actuated.

11. 8. The gas-actuated needle-free injector of claim 7, further comprising a pressure adjustment cylinder configured to adjust the first pressure of the first gas spring and the second pressure of the second gas spring.

12. 12. The gas-actuated needle-free injector according to claim 11, further comprising: a first connecting tube including one or more first valves connecting the pressure adjustment cylinder and the first gas spring; and a second connecting tube including one or more second valves connecting the pressure adjustment cylinder and the second gas spring.

13. 2. The gas-actuated needle-free injector according to claim 1, further comprising a pressure adjusting cylinder configured to adjust the pressure of the gas spring.

14. 14. The gas-actuated needle-free injector according to claim 13, further comprising a connecting tube including one or more valves connecting the pressure adjusting cylinder and the gas spring.

15. 1. A method of delivering a fluid, comprising: receiving a fluid into a dispensing chamber of a gas-actuated needle-free injector, the gas-actuated needle-free injector having a gas spring in communication with a piston, the gas-actuated needle-free injector further having a ball screw coaxial with the gas spring and the dispensing chamber and configured to receive at least a portion of the piston, the ball screw configured to move the piston between a first position and a second position; and actuating the gas spring to eject the fluid from the dispensing chamber.

16. a nozzle defining an injection orifice; a flexible hose connected to a fluid reservoir, said flexible hose connected to said nozzle immediately adjacent said injection orifice.

17. 17. The needle-free injection device of claim 16, wherein the flexible hose is connected to the nozzle within about 10 cm of the injection orifice.

18. 17. The needle-free injection device of claim 16, wherein the flexible hose is connected to the nozzle within about 2 cm of the injection orifice.

19. 17. The needle-free injection device of claim 16, wherein the flexible hose is a resilient hydraulic flexible hose.

20. 17. The needle-free injection device of claim 16, further comprising means for moving the fluid from the fluid reservoir to the nozzle for dispensing the fluid from the injection orifice.

21. A needle-free injection device comprising a gas-actuated needle-free injector having a first portion that is a wearable component and a second portion that is a handheld administration device.

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