Dose-Controlled Syringe

Abstract

A syringe system (1) for delivering a drug or pharmaceutical formulation into a patient's body is provided, comprising a hollow needle (200) disposed at the distal end (113) of a housing and an actuator provided for manual operation by a user, the actuator being mechanically coupled to the interior of the needle (200) by a plunger system, the syringe system (1) being particularly suitable for delivering minute doses of the drug or formulation. According to the invention, this is achieved by the plunger system comprising an actuator plunger rod (118a, 144a, 306) and a delivery plunger rod (118b, 128, 144b) mechanically coupled to the actuator plunger rod (118a, 144a, 306) by a transmission system, the transmission system converting the stroke of the actuator plunger rod (118a, 144a, 306) into the stroke of the delivery plunger rod (118b, 128, 144b) at a predetermined conversion ratio.

Description

[Technical Field]

[0001] The present invention relates to a syringe system, in particular a precision or micro-dose manual syringe system, for delivering a drug or pharmaceutical formulation into a patient's body, comprising a hollow needle disposed at or attachable to a distal end of a housing, and an actuator provided for manual operation by a user, the actuator being mechanically coupled to the needle or the interior of the distal end by a plunger system. [Background technology]

[0002] Glass and plastic prefilled or ready-to-fill syringes are available for use with the formulation already in the syringe and ready to use. There are two types: the first has a luer connection for attaching a hypodermic needle. The second type, the fixed-needle syringe, has a needle already attached. Both types require lubrication with silicone oil to facilitate stopper or plunger movement.

[0003] An alternative to prefilled syringes is a cartridge that includes a glass or plastic barrel, a pierceable septum held by a crimped metal ferrule at one end, and a stopper / piston at the other. A septum-piercing needle or cannula is used to pierce or puncture the septum, creating a fluid pathway between the cartridge drug contents and the injection needle or port. Such a configuration is typically used in pen-type injectors, such as insulin pens and cartridge-based dental syringes.

[0004] Both pre-filled syringes have a moving piston or stopper that can be attached to a plunger rod that has a plunger flange at the end that is designed to be manually pressed, usually by the thumb, to deliver the liquid or medication.

[0005] Cartridges are available in ready-to-fill and much cheaper bulk form. They can be filled like a syringe by capping, filling, and stoppering, or they can be stoppered, filled, and capped to make them bubble-free.

[0006] Some injections, particularly ophthalmic injections, require very small doses, sometimes as little as 20 microliters, but conventional syringes are of limited use for delivering such small volumes because they require very careful handling for proper administration. Summary of the Invention

[0007] It is therefore an object of the present invention to provide a syringe that is particularly suitable for delivering such small doses. In particular, a syringe should be provided that can be used with a variety of drug containers, including cartridges and pre-filled syringes, especially for the delivery of small doses.

[0008] According to the invention, this object is achieved by a syringe system as claimed in claim 1.

[0009] More specifically, according to one aspect of the present invention, the above-identified object is achieved in that the plunger system comprises an actuator plunger rod and a delivery plunger rod mechanically coupled to the actuator plunger rod by a transmission system, the transmission system converting a stroke of the actuator plunger rod into a stroke of the delivery plunger rod at a predetermined conversion ratio.

[0010] Preferred embodiments of the invention are defined in the dependent claims.

[0011] The present invention is based on the consideration that small doses typically require very small displacements of the stopper or the plunger driving the stopper in the barrel of a syringe, or alternatively, in a pre-filled cartridge.To enable such particularly small displacements on the delivery side of the syringe, a suitable and relatively easy actuation of the driving plunger according to one embodiment of the present invention can be achieved by providing a transmission system between the actuator and the stopper / plunger, which converts the stroke applied by the user to the actuator into a relatively small displacement of the plunger or stopper for actual drug delivery.In particular, the axial plunger flange movement according to one embodiment of the present invention may be greater than the axial movement of the stopper.

[0012] In particular, a syringe system according to an aspect of the present invention comprises:

[0013] a finger pad or flange or finger ring at a proximal end and an injection port at a distal end; a syringe housing capable of securely holding a drug container having a drug delivery means at the distal end of the barrel and a stopper / piston located near the proximal end of the barrel for containing a medicament or other formulation between the distal and proximal ends; a mechanical force multiplier mechanism including a pivoting lever that translates axial movement of the actuation plunger rod into a smaller axial movement of the delivery plunger rod, the mechanical force multiplier mechanism being held within a movable housing that is free to move axially relative to the syringe housing from a first position to a second position, the movable housing being locked in the second position; an actuation plunger rod having a finger pad at its proximal end and initially in communication at its distal end with the movable housing of the mechanical force multiplier mechanism; a delivery plunger rod having a proximal end attached to the pivoting lever of the mechanical force increasing mechanism and a distal end contacting but not attached to the container stopper; When depressed by a user, the actuation plunger rod causes the movable housing to move axially from a first position to a second position, axially displacing the delivery plunger rod and preparing the syringe system for injection; When used with cartridges, the septum needle is rigidly retained within the syringe housing and in fluid communication with an injection port protruding from a distal end of the syringe housing, the cartridge is axially retained in a first position and prevented from substantially independent forward axial movement within the syringe housing, and movement of a movable housing of a mechanical force multiplier mechanism urges the delivery plunger rod and cartridge from the first position to a second position where the septum needle pierces the septum and thereafter presses against a cartridge stopper to prime the syringe system; Alternatively, a threaded fitting including means for connecting the injection needle and septum needle combination projects from the distal end of the syringe housing, the cartridge is axially held in place and prevented from axial movement within the syringe housing, and after the user attaches the dual needle that pierces the septum, movement of the movable housing of the mechanical force multiplier mechanism pushes the delivery plunger rod and stopper to prime the syringe system; When used with a prefilled syringe: The pre-filled syringe and / or injection port protrude from the distal end of the syringe housing, the pre-filled syringe is held in a predetermined axial position and prevented from moving axially within the syringe housing, and movement of the movable housing of the mechanical force multiplier mechanism pushes the delivery plunger rod and stopper to prime the syringe system; After priming the device, the movable housing is locked in its second position and cannot move further axially, whereupon the actuation plunger rod rotates, thereby communicating with the pivot lever and allowing it to be pushed axially against the pivot lever, and thereafter, when the actuation plunger rod is pushed, a precise dose of the contents of the container is expelled through the injection port, determined by the axial movement of the delivery plunger rod, which axial movement is determined by the movement of the pivot lever and its precise outer dimensions and shape.

[0014] In one aspect considered independently inventive, the transmission system may comprise a conversion lever. In this embodiment, the conversion lever may be preferably mounted in a housing pivotable about an axis such that the actuator plunger engages the conversion lever at a drive offset relative to the axis to drive rotation of the conversion lever about the axis, and the delivery plunger is arranged to engage the conversion lever at a bearing offset relative to the axis. With such a design, a predefined stroke ratio can be provided in a reliable and precise manner. This preferred embodiment allows for a particularly high stroke conversion ratio, thus allowing for very small displacements of the delivery plunger rod for a "normal" displacement of the actuator plunger rod, thereby enabling particularly small doses to be delivered reliably.

[0015] In one aspect of this embodiment, the conversion lever is preferably contoured and may have several flat and curved surfaces. After the conversion lever completes its intended rotation, it may rest in a position where a first of the flat surfaces abuts the flange of the actuation plunger. A second of the flat surfaces may then abut the flange of the delivery plunger. In a preferred embodiment considered independently inventive, the lever of this design may be configured so that the first "upper" plane is essentially parallel to the second "lower" plane. This configuration in the end position provides "inherent stability" in the sense that once the lever reaches its designed end position and the flat surfaces abut their respective counterparts, i.e., the flanges of the respective plunger rods, they can no longer rotate in the rotational direction. This makes the rotation self-limiting, eliminating the need for additional stops. This is particularly useful for "priming" designs.

[0016] In yet another preferred embodiment, which is considered independently inventive, the delivery system is designed to first have a priming stroke of the actuator rod before an actual ejection stroke for ejecting a drug or formulation from the hollow needle is possible. In such a configuration, ejection of a drug or formulation from the hollow needle by the delivery plunger may be prevented until after the priming stroke has been performed. In particular, in one aspect, the housing of the applicator system may include at least two housing components movable relative to one another, and the priming stroke may be affected by moving two of the housing components relative to one another, particularly by pressing two of the housing components together.

[0017] Preferably, in those embodiments in which priming is desired, expulsion of the drug or pharmaceutical formulation from within the hollow needle by the delivery plunger rod is prevented until after the priming stroke has been performed.

[0018] If priming is not required, the housing of the mechanical boost mechanism may be fixed in place relative to the syringe housing, or the mechanism may be fixed to the housing, in which case the user simply rotates to unlock it as needed, depresses the finger pad on the plunger, and injects the container contents through the mechanical boost mechanism.

[0019] The pivoting lever may be a pivoting cam-shaped element or a simple pivoting cantilever or any other pivoting lever.

[0020] There may be tolerance gaps between the movable housing of the mechanical boost mechanism and the actuating and delivery plunger rods that allow free axial movement. These tolerance gaps are filled when the device is primed. The axial movement of the actuating plunger rod does not determine the axial movement of the delivery plunger rod, but that axial movement must be sufficient to fully rotate or pivot the pivot lever from its first position to its second position. These two positions are determined by stops on the movable housing.

[0021] The injection port may be a needle for subcutaneous, intravitreal or other injection, or may be a connector, such as a luer connector or other connector type, to which a needle or line may be connected.

[0022] It should be noted that when the injection needle is fixed to the syringe body or prefilled syringe, the syringe can generally only be used continuously for one subject or patient.If the device has a luer or threaded connection, the needle may be replaced after each administration and can be used continuously for multiple patients, or daily or at other intervals for single or multiple patients depending on the drug.

[0023] Once primed, the syringe is used by first rotating the plunger rod, then inserting the needle into the injection site and depressing the plunger rod. The plunger rod travel is greater than the stopper travel, providing better feedback to the user, especially when very small doses are being injected and the stopper travel is less than 2 mm or even less than 1 mm. Mechanical boost is also highly advantageous when injecting viscous liquids.

[0024] In the case of a pre-filled syringe, the pre-filled syringe may be held by a shoulder at its distal end like a cartridge, or by its flange at its proximal end, in which case most of the syringe barrel is exposed beyond the short syringe housing, allowing for easy visualization of the drug contents.

[0025] If possible, the user may change the needle after each dose is delivered.

[0026] The cartridge or pre-filled syringe may be inserted pre-sterilized or by the user.

[0027] The cartridge or pre-filled syringe may be inserted axially or radially. If inserted axially, the user attaches or places the plunger rod after inserting the cartridge. If inserted radially or laterally, the plunger rod may already be in place.

[0028] The present invention is generally a disposable device that is provided with one container or inserted by the user.Some embodiments may be reusable when multiple containers can be used, particularly in the case of cartridge-based devices where the septum needle is replaced with the injection needle, or in the case of pre-filled syringe-based devices where the needle is attached by the user.In either case, the drug container is inserted by the user.

[0029] In a movable cartridge, the cartridge may be held in the first position by a deformable or movable stop on the cartridge shoulder or cap to prevent the cartridge from moving forward during shipping or handling or after insertion by the user. The cartridge may be held in place, or even retained, by friction or an interference fit. The device may have a locking mechanism that holds the cartridge in place before use. If the device has a locking mechanism, it must be unlocked so that the cartridge can be pushed to the second position by pressing the plunger rod. The lock may hold a deformable stop in the closed position that is released by activating a switch or button, or other means, such as removing the cap.

[0030] When used with a cartridge, the device may include a cap to cover the needle or luer or other connection before use. In the case of a removable cartridge, the cap may be used to lock the cartridge in a first position before use. This locking mechanism may be part of the cap or housing, in which case the lock is held in the locked position by the cap.

[0031] The drug container may be filled with or without air or bubbles, which can be expelled during priming prior to the first injection.

[0032] The drug container may be a double-chamber or dual-chamber container. In this case, the first axial movement may additionally be used to mix the contents of the two chambers, and the second axial movement may be used to prime and expel air from the container. If the drug container is a cartridge, particularly a transfer cartridge, the first axial movement also moves the cartridge forward, and the septum is pierced by the septum needle before mixing occurs. The contents of the drug container may be a liquid and a dry powder or two liquids.

[0033] The entire assembly, with or without the drug container, may be terminally sterilized within the blister or other outer packaging. Depending on the type of drug and the packaging and device materials, the system can be sterilized using moist heat (steam), dry heat, gamma or other radiation, ethylene oxide gas, vaporized hydrogen peroxide, chlorine dioxide gas, vaporized peracetic acid, or nitrogen dioxide. If terminally sterilized with the drug container in place, the terminal sterilization may be tailored to only sterilize the exterior of the syringe and the drug container. However, terminal sterilization can also be tailored and used to further sterilize the drug contents themselves, if desired.

[0034] Furthermore, it should be noted that the present invention may terminally sterilize pre-filled syringes with luer connectors and containing formulations with precise fixed injection volumes as low as 10 microliters, a feature that is entirely unique to the present invention.

[0035] The drug container barrel may be made of glass or plastic such as COC or COP. The syringe system may be adapted for subcutaneous, intramuscular, intradermal, ophthalmic, intravascular, intravenous, or any other type of injection.

[0036] The present invention may be used to deliver or inject any liquid into any body, including humans or animals, for any purpose.

[0037] In another aspect of the present invention, which is considered independently inventive, the syringe may be intended for ocular, intravitreal, or intraocular injections, where dose accuracy is critical. For this application, a small-diameter 0.5 ml prefilled syringe, either fixed needle or Luer type, may preferably be used. The small diameter allows for sufficient stroke length for feedback, as doses are approximately 20 to 50 microliters. Another significant advantage of the present invention is that the user cannot unintentionally reverse the movement of the plunger rod, eliminating the possibility of air being drawn into the needle and injected into the eye.

[0038] The present invention may have either a visual, audio or tactile indicator to alert the user to the end of the priming and / or dosing state.

[0039] The present invention is a significant improvement over the use of vials and disposable syringes in that no transfer of drug solution from a vial to a syringe is required, thereby reducing the possibility of clinical error and requiring far fewer user steps.

[0040] The present invention is a significant improvement over existing prior art microdose delivery systems due to its simpler construction. The present invention in one aspect is a microdose syringe system that is elegant in its simplicity and easy to implement, and that can be terminally sterilized along with the drug content.

[0041] In particular, the syringe of the present invention can terminally sterilize the pre-filled syringe or cartridge that contains the preparation, which can deliver a precise fixed injection amount as low as 10 microliters.Even for very small injection amounts, the transfer of drug solution from vial to syringe is not required.This feature is completely unique to the present invention.

[0042] Ophthalmic pre-filled syringes generally need to be terminally sterilized.When pre-filled syringes are used, because the needle contacts the syringe contents and is sealed by gas-permeable cap, fixed needle pre-filled syringes cannot be sterilized, so only Luer type can be used.When using, users need to attach a needle after removing the device from the sterile blister, which may cause sterility to be lost.

[0043] Another aspect of the invention uses a fixed needle cartridge system in which the needle does not come into contact with the contents during sterilization, but is at the same time a component of the device and can therefore be terminally sterilized, which is a major advantage as the device is ready to use after removal from the sterilization blister.

[0044] Various embodiments of the present invention are provided by way of example in the drawings. [Brief explanation of the drawings]

[0045] [Figure 1a] 1 shows a cartridge according to the "prior art" international standard ISO 13926. [Figure 1b] 1 shows a Luer-type pre-filled syringe according to the "prior art" international standard ISO 11040. [Figure 2a] 1 shows a single-dose cartridge-based syringe generally in accordance with PCT / EP2022 / 075752, including a fixed septum needle and means for attaching an injection needle or luer. [Figure 2b] 1 shows a generally prior art single dose cartridge-based syringe with means for attaching a double ended needle. [Figure 3] The present invention is shown as applied to and having an integrated precision multi-dose mechanism for use with an axially movable cartridge in combination with a fixed septum needle. [Figure 4] 10 shows details of a transmission box of the present invention having an integrated precision multi-dose mechanism for use with an axially fixed cartridge and means for receiving a double ended needle. [Figure 5] 1 shows details of a transmission box of the present invention with an integrated precision multi-dose mechanism for use with pre-filled syringes. [Figure 6] 10 shows details of a transmission box of the present invention having an integrated precision multi-dose mechanism for use with an axially movable cartridge in combination with a fixed septum needle. [Figure 7] 1 shows a pivoting lever or lever / cam with a self-limiting mechanism for use with the present invention. [Figure 8] 10 shows an alternative configuration of a transmission box for a pre-filled syringe or cartridge. [Figure 9] 1 shows an alternative swivel lever. [Figure 10]1 shows the complete assembly of the present invention using a pre-filled syringe. [Figure 11] 10 shows an alternative complete assembly of the present invention using a pre-filled syringe. [Figure 12] 10 shows an alternative complete assembly of the present invention using a pre-filled syringe.

[0046] Generally, identical parts are provided with the same reference numerals in all the drawings. The present invention will be described below mainly with reference to the illustrated embodiments. The aspects mentioned below may be considered independently inventive, either separately or in combination with each other. However, other embodiments are of course also possible and are covered by the present invention.

[0047] Embodiments of the present invention include a syringe system 1 that is preferably suitable for use with a pre-filled cartridge 110 or for use as a pre-fillable syringe 110a.

[0048] In FIG. 1a, cartridge 110 has a plastic or glass barrel 111, an open proximal end 119, and a necked-down, flanged end 113b at distal end 113 that forms shoulder 113a with barrel 111. A movable stopper 112 at open end 119 and a rubber cap assembly 95 at necked-down or distal end 113 seal the formulation solution 117 within barrel 111. Cap assembly 95 has a septum 114 held in place by a metal crimp or ferrule 115 that is crimped onto cartridge neck 113. Ferrule 115 has a hole 116 that allows needle insertion through septum 114.

[0049] Such cartridges are fully described in ISO 13926 and can have glass or plastic barrels.

[0050] In the following figures, cap 95 may refer to the combined ferrule and septum assembly as described in FIG. 1a.

[0051] In Figure lb, prefillable syringe 110a has a plastic or glass barrel 111a with an open proximal end 119a with a finger flange 121 and a waisted end 113 forming a luer connection 98 sealed by a shield 96 at the distal end 113. A movable stopper plunger 112a at the open proximal end 119a and a needle shield 96 at the distal end seal the formulation solution 117 within the barrel 111a.

[0052] FIG. 2a shows a basic single-dose syringe system of the prior art. The cartridge 110 is mounted in a first position within a housing 127. A luer connection 123, serving as a means for attaching a hollow needle 200, is located at the distal end of the syringe housing. A septum needle 124 is securely held in the forward or distal end of the housing 127 and is in fluid communication with the luer or other connector 123 at the distal end of the housing 127. The cartridge 110 is free to move axially toward the septum needle 124 under user force to a second position. When pushed axially by pressing the plunger rod 128a with pad 129a, the septum needle 124 pierces the cartridge cap 95, thereby establishing fluid communication between the cartridge liquid contents and the luer connection 123.

[0053] The user can use thumb pad 129a and finger flange 131 to push plunger rod 128a in the normal manner to axially push cartridge 110 into the second position, enable the syringe system, prime the system if necessary, and perform an injection of contents 117 via luer connection 123.

[0054] Connection 123 may be a luer slip or luer lock for a hypodermic needle or tubing.

[0055] A gas pathway 135 may be located within the housing 127 to facilitate gas sterilization of the needle assembly.

[0056] Prior to use, cartridge 110 may be locked in place in the first position to prevent the cartridge septum from being unintentionally pierced by needle 124. Alternatively, cartridge 110 may be held in the first position by friction, for example, by friction at a cartridge shoulder.

[0057] Figure 2a shows an embodiment in which cartridge 110 is movable from a first position to a second position and has a septum needle 124 securely attached to a housing 127. When cartridge 110 is fixed in place and the user installs a double-ended needle, the cartridge is always fixed in the second position, and the septum needle is not attached to the housing, but there is a passageway that allows the double-ended needle to pass through. This is shown in Figure 2b.

[0058] In Figure 2b, the luer connection is replaced with a threaded fitting 123a that includes a hole or passageway 136 that allows for the insertion of a septum needle. The cartridge 110 is fixed in place and cannot move axially. Such an arrangement can be used with prior art double-ended dental and / or insulin needles.

[0059] FIG. 3 illustrates the basic concept of the present invention with an integrated precision multi-dose mechanism for use with a movable cartridge having a fixed septum needle.

[0060] The plunger rod according to one embodiment of the present invention is divided into two parts: an actuation plunger rod 144a connected to a thumb pad 146, and a delivery plunger rod 144b connected to the cartridge stopper 112, and the two rods 144a and 144b are connected to each other via a transmission box 140. The transmission box 140 has a gearing configuration that allows actuation plunger rod 144a to travel a longer distance than delivery plunger rod 144b when very small volumes are injected, resulting in very small movements of the corresponding stopper 112 and delivery plunger rod 144b, providing a better feel to the user.

[0061] In Figure 3, the device is shown with cartridge 110. To prime, cartridge 110 is moved forward so that septum needle 124 pierces septum 114 to expel air trapped in the needle and cartridge 110. Note that cartridge 110 is shown with a luer slip connector 123 for receiving a hypodermic needle, which is attached prior to priming the device.

[0062] It should be noted that a similar concept to transmission box 140 can be applied to an axially fixed cartridge or an axially fixed pre-filled syringe.

[0063] FIG. 4 illustrates one embodiment of the present invention having a precision dosing system. Only the mechanical boost mechanism of the syringe system is shown in FIG. 4, along with the relationship between the actuation plunger rod 306 and the delivery plunger rod 128. The illustrated embodiment is for use with an axially fixed cartridge 110. The cartridge barrel 304 is rigidly held in the syringe main housing 302. The actuation piston rod 306 has an off-center extension 306a of small cross section. The movable housing 312 holds a pivot lever or lever 321, which pivots on an axis 321a. Travel stops 323 and 323a limit the rotational travel of the pivot lever 321. The movable housing 312 has a hole 312a at its upper end and is fully open at its lower end.

[0064] In FIG. 4a, movable housing 312 is in a first position, generally free to move between tolerance gaps 307 and 307a. In this position, the syringe system is ready for use, with extension 306a axially aligned with the top of movable housing 312. To prime the device, the user presses actuation plunger rod 306. This action forces movable housing 312 downward against delivery plunger rod 128. The two tolerance gaps 307, 307a close, and pivot lever 321 engages delivery plunger rod 128. In accordance with an embodiment of the present invention, pivot lever 321 is prevented from pivoting by travel stop 323. Further pressing actuation plunger rod 306 moves delivery plunger rod 128 axially downward, priming the device by expelling any drug solution and any air bubbles. The delivery plunger rod moves a distance 331. The final rest position after priming is shown in Figure 4b, where the movable housing 312 according to yet another embodiment of the present invention is locked in its second position to prevent further movement by lock 325. Note that to expel any air bubbles, the orientation needs to be reversed as shown in Figure 3, with the delivery plunger rod at the top.

[0065] After priming, the user rotates the actuation plunger rod 306 until the extension 306a is axially aligned with the movable housing bore 312a. This position is shown in FIG. 4c. The user then simply pushes the actuation plunger rod again, causing it to push against the pivot lever 321, pivoting the pivot lever until its underside presses against the delivery plunger rod 128. The tolerance gap 307b is closed when the actuation plunger rod 306 is first pushed. The actuation plunger rod travels a distance 333, while the delivery plunger rod travels a smaller distance 335, until the pivot lever's rotation is stopped by stop 323a. The ratio of the two is the mechanical gain. The ratio is a function of the shape and size of the pivot lever 321 and the axial distance between stops 323 and 323a.

[0066] Figure 5 shows one embodiment of the present invention with a precision dosing system. The embodiment shown is for use with an axially fixed pre-filled syringe. The mechanism is the same as that described in Figure 4. The differences are as follows:

[0067] Syringe barrel 304a has flange 304b held within housing 302 by feature 302a. Stop 323a of FIG. 4 is replaced by a side wall of movable housing 312, and lock 325 of FIG. 4 is replaced by allowing the movable housing to be held by syringe barrel 304a at point 326 in the second position.

[0068] 4 and 5, it can be seen that tolerance gaps 307, 307a and 307b do not affect the final axial travel distance of delivery plunger rod 128 during the injection stroke, and the tolerance is filled by the movement of actuation plunger rod 306 during the priming stroke. This ensures a precise dose during the injection stroke that is determined only by the shape and size of pivot lever 321 and the axial distance between stops 323 and 323a or between stop 323 and the side wall of the movable housing.

[0069] Figure 6 shows one embodiment of the present invention having a precision dosing system. The illustrated embodiment is for use with a movable cartridge 110 and fixed septum needle 124 as described in Figure 3. The mechanism is the same as that described in Figure 4, except that during the priming stroke, movement of the delivery plunger rod 128 first pushes the entire cartridge barrel 304 to its second position where the cartridge septum is pierced to enable priming.

[0070] The cartridge housing may have an integral retaining needle, which does not come into contact with the contents during sterilization, but is at the same time a component of the device and can therefore be terminally sterilized. This is a major advantage as the device is ready for use after removal from the sterilization blister.

[0071] 4, 5, and 6, it should be noted that the pivot lever 321 may alternatively be positioned to reverse the mechanical boost that causes the delivery plunger rod 128 to move axially more than the actuation plunger rod 306.

[0072] Another pivoting lever or lever / cam 801 with a self-limiting mechanism is shown in Figure 7. Lever 801 is free to rotate, as indicated by arrow 802, and has three flat surfaces 831, 833, and 835, pivoting about axis of rotation 811 with center 813. Figure 7a shows lever 801 after priming, but before injecting the correct dose. Actuation plunger rod 803 has a flange 805 that abuts the top of curved surface 837 of lever 801. The lower flat surface 835 of lever 801 abuts flange 806 of delivery plunger rod 803.

[0073] FIG. 7b shows lever 801 after delivering the correct injection volume. Lever 801 is rotated by plunger rod 803 as indicated by arrow 804, as shown at 802 in FIG. 7a. Plane 831 is tangent to flange 805 of actuation plunger rod 803. Vertical centerline 817 of rotation axis 811 passes through flange 805 of actuation plunger rod 803. Once lever 801 reaches the position shown, it can no longer rotate in direction 802. Because the rotation is self-limiting, stop 323, as shown in FIGS. 5 and 6, is not required. This is a major advantage of this independent embodiment of the invention, as it eliminates another potential tolerance issue.

[0074] A lever 801 as depicted in FIG. 7 according to an embodiment of the present invention can be used with the devices shown in FIGS.

[0075] FIG. 8a shows a schematic diagram of the present invention in which a mechanical advance mechanism 401 is held within the confines of housing 110b, and in FIG. 8b mechanism 403 is held outside the confines of housing 110c.

[0076] Figure 8a shows an axially movable cartridge in combination with a fixed septum needle, and Figure 8b shows a fixed needle pre-filled syringe. It should be noted that Figure 8a can alternatively be used with a pre-filled syringe, and Figure 8b can be used with an axially movable or fixed cartridge.

[0077] An alternative pivot lever is shown in Figure 9. The beam and fulcrum or cantilever configuration has a beam 451 that pivots at point 452. Beam 451 is shown engaging actuation plunger rod 306b at horizontal distance 421 from pivot point 452 and engaging delivery plunger rod 128b at horizontal position 423 closer to pivot point 452. Beam or pivot lever 451 is also held in place by stop 323c.

[0078] When pushed by actuation plunger rod 306b, beam or pivot lever 451 pivots to a position indicated by 453, its travel limited by the side wall or stop 333b of the movable housing. The distance traveled by actuation plunger rod 306b is 425, and the distance covered by delivery plunger rod 128b is 427. The ratio of the two is the mechanical boost, which is a function of the ratio of the pivot distances 421 and 423 of pivot lever 451 and the axial distance between stops 323c and 333b.

[0079] Figure 10 shows one embodiment of the complete assembly of the present invention. Figure 10a shows the device from the outside, and Figure 10b shows a cross-section of the device rotated 90 degrees relative to Figure 10a. Main housing 302 has transfer housing 312 slidably mounted therein. Transfer housing 312 has a pivoting lever 321 therein. Actuation plunger rod 118a and delivery plunger rod 118b communicate with lever 321.

[0080] Pre-fillable syringe 110a has a needle 200 attached to its distal end and a barrel 111a having a stopper 112 and contents 117 therein.

[0081] Prefillable syringe 110a is attached to outer housing 302 by its flange 121 and is held securely in place by screw 126a at finger grip 126. Syringe 110a is shown with a hypodermic needle 200 attached. Syringe 110a may be a fixed needle syringe in which needle 200 is glued to syringe barrel 111a, or may have a luer connector or other connector configured to receive needle 200.

[0082] Lock or key 142 prevents actuation plunger rod 118a from moving during handling and priming of the device. To prime the device, thumb pad 120 is depressed by the user, at which point inner housing 312 moves relative to outer housing 302, moving delivery plunger rod 118b, and thus stopper 112a, to fill needle 200 with its liquid contents and remove any air in needle 200 and any trapped air bubbles in the syringe. At the end of the priming stroke, inner housing 312 is securely held axially within outer housing 302 by an interference fit or lock or catch, or by any other means.

[0083] To inject contents through needle 200, the user releases lock 142 and presses thumb pad 120, which pivots lever 321, pushing plunger rod 118 and stopper 112a further down to deliver a precise volumetric dose, which is determined by the dimensions of lever 321.

[0084] Figure 11 shows an exploded view of the transfer housing of another embodiment of the complete assembly of the present invention. Main housing 302b has transfer housing 312b therein. Transfer housing 312b has pivot lever 321 therein. The delivery plunger rod is not shown in Figure 11.

[0085] The embodiment of Figure 11 differs from the embodiment shown in Figure 10 only in that transfer housing 312b has a pin 314 that engages with internal threads on main housing 302b. To prime the device, transfer housing 312b is rotated by grip 313. To change the dose, lever 321 can be changed. For a 20 microliter dose, lever 321d is used, and for a 50 microliter dose, lever 321e is used.

[0086] The embodiment of FIG. 11 according to aspects of the present invention has advantages over the embodiment shown in FIG. 10. In FIG. 10, the end of priming is reached when axial movement reaches an interference fit or catch. Due to tolerances, it may be difficult to hold the transfer housing axially without movement. Because the dosing stroke may be very small, axial movement of the transfer housing during dosing may result in a large dose error. In FIG. 11, the transfer housing 312 rotates within the main housing 302 and has a tight fit at the end with no axial movement possible.

[0087] FIG. 12 shows the same embodiment as FIG. 11. In FIG. 12a, the device is shown without a needle attached to the luer 123 prior to use. The lock 142 is in place, and the delivery housing 312a fully extends from the main housing 302a. In FIG. 12b, the needle 200 is attached to the luer 123, and the device is primed by rotating the delivery housing 312a with the grip 313. The syringe stopper 112 travels a distance 171 that is sufficient to prime the volume of contents 117, purging any air bubbles in the syringe and filling the needle 200 with liquid. In FIG. 12c, the device is in use. The lock 142 is removed, the finger pad 120 is depressed, and the actuation plunger rod 118a rotates the lever 321, displacing the stopper 112 the amount indicated by 169, delivering the correct dose of contents 118b to the injection site. [Explanation of symbols]

[0088] 1 Syringe System 95 Cap 96 Shield 98 Lure Connection 110 cartridges 110a Prefillable Syringe 110b, 110c housing 111, 111a barrel 112, 112a stopper 113 Distal end 114 Septum 115 Ferrule 116 holes 117 Preparations 118a Actuating plunger rod 118b Delivery plunger rod 119, 119a proximal end 120 thumb pad 121 flange 123 Lure Connection 123a Threaded joint 124 Septum needle 126 Finger Grip 126a Screw 127 Housing 128 Delivery plunger rod 128a Plunger Rod 129a Pad 131 Finger flange 135 Gas Route 136 Passage 140 Transmission Box 142 Rock 144a Actuating plunger rod 144b Delivery plunger rod 146 Thumb Pad 169 quantity 171 distance 200 stitches 302 Main Housing 304 cartridge barrel 304a Syringe Barrel 304b flange 306 Actuating plunger rod 306a extension 307, 307a, 307b Tolerance Gap 312 Transmission Housing 312a hole 313 Grip 314 pins 321, 321d, 321e levers 321a axis 323, 323a Moving stop part 323c Stop 325 Rock 326 points 331, 333, 335 distance 333b Stop 401, 403 Advance mechanism 421 distance 423 position 425 distance 427 distance 451 Beam 452 Swivel shaft 453 position 801 Lever 802 Arrow 803 Actuating plunger rod 804 Arrow 805, 806 flanges 811 Rotating shaft 813 center 817 Center line 831, 833, 835 plane 837 Curved surface

Claims

1. 1. A syringe system (1) for delivering a drug or pharmaceutical formulation into a patient's body, comprising: a housing having a distal end (113) to which a hollow needle (200) can be attached; and an actuator provided for manual operation by a user, the actuator being mechanically coupled to the interior of the needle (200) or to the distal end (113) of the housing by a plunger system, the plunger system comprising an actuator plunger rod (118 a, 144 a, 306) and a delivery plunger rod (118 b, 128, 144 b) mechanically coupled to the actuator plunger rod (118 a, 144 a, 306) by a transmission system, the transmission system converting a stroke of the actuator plunger rod (118 a, 144 a, 306) into a stroke of the delivery plunger rod (118 b, 128, 144 b) at a predetermined conversion ratio.

2. 2. The syringe system (1) according to claim 1, wherein the transmission system comprises a conversion lever (321, 451, 801).

3. 3. The syringe system (1) of claim 2, wherein the conversion lever (321, 451, 801) is mounted within the housing pivotable about the axis (321a, 452, 813) such that the actuator plunger rod (118a, 144a, 306) engages with the conversion lever (321, 451, 801) at a drive offset relative to the axis (321a, 452, 813) to drive rotation of the conversion lever (321, 451, 801) about the axis (321a, 452, 813), and the delivery plunger rod (118b, 128, 144b) engages with the conversion lever (321, 451, 801) at a receiving offset relative to the axis (321a, 452, 813).

4. 4. The syringe system (1) of claim 2 or 3, wherein the conversion lever (321, 451, 801) is contoured and has several flat surfaces (831, 833, 835) and several curved surfaces (837), and a first flat surface (831) of the flat surfaces contacts the flange (805) of the actuation plunger after completion of rotation of the conversion lever (321, 451, 801).

5. 5. The syringe system (1) of claim 1, wherein the delivery system is designed to first have a priming stroke of the actuator plunger rod (118a, 144a, 306) before an actual ejection stroke for expelling the drug or pharmaceutical formulation from the distal end (113) is possible.

6. 6. A syringe system (1) according to claim 5, wherein the housing comprises at least two housing components movable relative to each other, and the priming stroke is affected by moving two of the housing components relative to each other.

7. 7. The syringe system (1) of claim 5 or 6, wherein the ejection of the drug or pharmaceutical formulation from within the hollow needle (200) or the distal end (113) by the delivery plunger rod (118b, 128, 144b) is blocked until after the priming stroke has been performed.

8. A syringe system (1) according to any one of claims 1 to 7, further comprising an indicator system arranged at the proximal end of the housing.

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