HK1055912B - Needleless syringe with prefilled cartridge - Google Patents

Description

Needleless injector with prefilled cartridge

Technical Field

This application is a partial continuation of serial No. 09/207,398 filed on 8.12.1998. The present invention relates to a needle-free injection system comprising a pre-filled cartridge.

Background

One of the problems inherent in the current packaging of liquid injectable drugs is that there is insufficient data regarding the biocompatibility of the interaction between those drugs and the thermoplastic containers. Although plastics are commonly used in many injection devices, most injectable drugs cannot be exposed to most plastics, except for a short period immediately prior to injection. This is because the drug or the injection solution may chemically react with the plastic or cause substances in the plastic to be dissolved into the injection solution, thereby generating impurities in the drug. Such exposure to plastic containers can lead to degradation of the drug during extended periods of storage. For these reasons, the pharmaceutical industry generally avoids the need for injectate storage in certain thermoplastic materials, such as polypropylene, which are often used in syringes and related injection accessories. Similarly, there is no long-term biocompatibility data for engineering or high strength thermoplastics such as polycarbonate, which are often used in needleless injection systems.

For this reason, the injection liquid is generally stored in a glass bottle. The injectate chamber of the needleless injection system is filled from a vial containing the drug immediately prior to injection. This typically requires the use of a vial adapter, sometimes referred to as a blunt injection device or access needle that can pierce a protective membrane on the top of a vial and then introduce the injectate into the chamber or cartridge of the needleless injection system.

This conventional approach has a number of disadvantages. The extra step of having to transfer the drug from the vial to the needleless injection system, for example, is time consuming and can be cumbersome for patients who want to inject the drug at home and who may have some physiological weakness. Even for those in good condition, a vial adapter is necessary and must be sterile to prevent contamination of the solution. Vial adapters typically include a transfer needle with a sharp tip at one end to facilitate penetration of the glass membrane, but this tip can cause injury, inadvertent injection of the solution into the operator or administrator, and/or contamination of the solution. The additional step of filling the needle-free injection system immediately prior to injection may also result in leakage and waste of injectate and, if mishandled, the introduction of air into the injection system. The introduction of air can present difficulties to needleless injection systems because, unlike conventional needle and injection systems, air cannot be easily expelled from the chamber of the needleless device. Thus, using an injection system in which a portion of the chamber is filled with air may result in a reduced dose of drug being injected into the patient. The pressure at which the injection is performed may also be inadequate. One advantage of Bioject corporation's needleless injection systems (assignee of the present invention) is that they are capable of injecting precisely predetermined amounts of injectate into predetermined, precise locations within the tissues of patients. The introduction of air can make it difficult to achieve this accuracy.

It is therefore an object of the present invention to provide for pre-filling of a cartridge for use with a needle-free injection system.

Disclosure of Invention

The present invention provides a cartridge and nozzle assembly having a nozzle with a valve receiving portion having a plurality of channels for facilitating flow of injectate to the nozzle orifice. Specifically, the assembly includes a cartridge having a plunger disposed at a rearward end thereof and having an interior thereof with a throat at a forward portion thereof, the cartridge further including a generally laterally extending interface surface. The assembly also includes a displaceable outlet valve initially disposed within the throat, the outlet valve having a channel-free valve body. The nozzle receives the cartridge in a rearwardly directed cartridge receiving portion and includes a front portion defining a valve receiving portion having a plurality of channels and a nozzle aperture. The interior of the cartridge thus has fluid passing through the channel to the bore. The nozzle also has a substantially extended interface surface adjacent the cartridge interface surface. Finally, a seal is provided between the cartridge interface and the nozzle interface for preventing or at least reducing leakage of injectate between the interfaces.

In another aspect, the present invention provides a needle-free injection device comprising: a cartridge having a plunger disposed at a rear end thereof and a front portion including an interior with a throat; a displaceable outlet valve initially disposed within the cartridge throat, the cartridge further including an outwardly facing interface surface; a push rod for selectively providing a driving force to drive the plunger in a forward direction; a nozzle for receiving a cartridge, the nozzle defining a rearward cartridge receiving portion and including a forward portion defining and terminating in a valve abutment surface having a plurality of passages and an injection orifice formed therein, the forward portion being configured to receive the valve when the valve is moved toward a forwardly disposed position such that the valve is disposed against the valve abutment surface such that the interior of the cartridge has fluid passing through the passages and into the orifice, the nozzle further including an inwardly facing interface surface abutting the cartridge interface surface; and a seal disposed between the cartridge interface and the nozzle interface for at least reducing leakage of injectate between the interfaces.

Another aspect of the invention provides a method for preparing a needle-free injection system. The method comprises the following steps (the order of reference is not necessary): (1) selecting a glass cartridge having a plunger positionable in the rearward end and a forward portion having an interior with a throat and an outlet valve positionable in the throat, the cartridge further comprising a substantially laterally extending interface; (2) positioning a seal on the cartridge rearward of the laterally extending interface; (3) positioning one of a plunger or an outlet valve within the cartridge; (4) filling the cartridge with an injection solution prior to positioning the other of the plunger or the outlet valve within the cartridge; (5) positioning the other of the plunger or the outlet valve within the cartridge; (6) selecting a nozzle comprising a rear, cartridge receiving portion and a front portion defining a valve receiving portion having a plurality of channels and an injection orifice formed therein, the front portion being configured to receive the valve when the valve is displaced toward the forwardly disposed position, the nozzle further comprising a substantially laterally extending interface surface; (7) mounting the cartridge into the nozzle to form a cartridge/seal assembly such that the interface is in abutment and the seal is disposed at such abutment rearward; and (8) maintaining the cartridge/seal assembly in a sterile environment prior to use.

Another additional aspect of the present invention includes the step of mounting the cartridge/nozzle assembly to the forward end of the injector by applying rearward pressure on the cartridge/nozzle assembly such that the injector ram applies a forward pressure on the plunger to move the outlet valve from the throat into the valve receiving portion and displace the injectate from the air in the forward portion of the nozzle.

In this last-cited aspect, an injection may be administered by actuating the injector, causing the injector ram to push the plunger forward, thereby causing the injectate to be driven out of the nozzle orifice.

Drawings

FIG. 1 is a side cross-sectional view of a pre-filled cartridge of the present invention, with the dashed lines showing an initial position prior to cartridge insertion and the solid lines showing the inserted position prior to initial pressurization;

FIG. 2 is an end sectional view taken along line 2-2 of FIG. 1, showing the cartridge in an inserted position;

FIG. 3 is a side cross-sectional view showing the location of the cartridge and nozzle within the preferred embodiment of the needle-free injection system;

fig. 4 shows an enlarged, partial side cross-sectional view of an adjacent portion of the cartridge/nozzle assembly of the embodiment of fig. 1 and the outlet valve, with the outlet valve shown in an unpressurized position.

FIG. 5 is a view corresponding to FIG. 4, but with the outlet valve shown in FIG. 5 inserted and displaced into its forward position;

FIG. 6 is an enlarged side view of the outlet valve of the embodiment of FIG. 1;

FIG. 7 is a side sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is an end sectional view taken along line 8-8 of FIG. 6 showing a forward portion of the outlet valve;

FIG. 9 is an end sectional view taken along line 9-9 of FIG. 4 showing a rear portion of the outlet valve;

fig. 10 is an isometric view of the outlet valve of fig. 1-9;

FIG. 11 is a side cross-sectional view of an alternative embodiment showing a diaphragm in the outlet valve position;

FIG. 12 is a side cross-sectional view of the embodiment of FIG. 11, wherein the diaphragm is broken;

FIG. 12B is an isometric view corresponding to FIG. 12A;

FIG. 13A is a side cross-sectional view of the second alternative embodiment with the outlet valve in the closed position;

FIG. 13B is a view corresponding to FIG. 13A, but with the outlet valve shown in FIG. 13B in its forward position;

FIG. 14A is an isometric view of the outlet valve corresponding to the outlet valve shown in FIGS. 13A and B, but with the flap of FIG. 14A notched to facilitate tearing when pressure is applied to the valve;

FIG. 14B is a view corresponding to FIG. 13A, but FIG. 14B shows the outlet valve with a notch pattern of the wings shown in FIG. 14A;

FIG. 14C corresponds to FIG. 14B, but the outlet valve shown in FIG. 14C is in its open position;

FIG. 15 is a partial side sectional view of another alternative embodiment of the nozzle without the cartridge or outlet valve showing a rib in the nozzle recess;

FIG. 16A is an enlarged side sectional view of the embodiment of FIG. 15, showing the cartridge and outlet valve in their closed positions;

FIG. 16B is a view corresponding to FIG. 16A, but with the outlet valve shown in FIG. 16B in its forward position;

FIG. 17A is a side cross-sectional view of an alternative embodiment of the present invention;

FIG. 17B is a view corresponding to FIG. 17A;

fig. 18 is a side sectional view showing the location of the cartridge and nozzle of an alternative embodiment shown in fig. 19-22;

FIG. 19 is a side cross-sectional view of the embodiment of FIG. 18 with the plunger in its rearward position prior to installation of the assembly into a syringe;

FIG. 20 is an end sectional view taken along line 20-20 of FIG. 19;

FIG. 21 is a side cross-sectional view of the embodiment of FIG. 18, but FIG. 21 shows the plunger in its forward position after the slave assembly has injected the injection solution; and

fig. 22 is an end sectional view taken along line 22-22 of fig. 21.

Detailed Description

The embodiments of fig. 1-10

The objects of the invention are most desirably accomplished when the invention takes the form of the embodiment shown in fig. 1-10. First, description will be made with reference to those drawings. Generally shown at 10 is a cartridge/nozzle assembly wherein the cartridge may be pre-filled with a liquid injection. The assembly includes: a cartridge 12, which in the preferred embodiment is formed of tempered glass; and a nozzle 14, which in the preferred embodiment is constructed of a high strength thermoplastic, typically polycarbonate. The nozzle 14 is of conventional design except that the rear portion (or left portion in fig. 1) includes a plurality of evenly spaced feet 16. In the illustrated embodiment, four such feet are included, positioned at 90 degree intervals around the nozzle, two of which are shown in phantom in FIG. 1. Alternatively, three or even two such feet may be used.

For a cartridge 12 in its partially inserted position, shown in phantom in fig. 1, the feet 16 may be biased radially outward and held there by the cartridge wall 18. Since the cartridge wall 18 tapers at its forward end 20, it is easy to insert the cartridge 12 into this partially installed position. The tapered wall 18 thus defines an internal throat 21 in the forward end of the cartridge 12. Typically, an O-ring 22 is provided between the cartridge and the nozzle 14 adjacent the tapered end of the front portion of the cartridge. A step 28 is included in the inner surface of the sidewall 30 of the nozzle 14 to provide a stop and a sealing surface for the O-ring 22 disposed between the tapered portion 20 of the cartridge wall 18 and the inner surface of the nozzle sidewall 30. In this way, the O-ring prevents the flow of injectate along the interface between the outer surface of the cartridge wall 18 and the inner surface of the nozzle sidewall 30. A plunger 24 is disposed within the wall 18 of the cartridge 12 and controls the injection of injectate out of the cartridge as desired by the operator. The cartridge 12 may be inserted into the nozzle 14 at the factory or user as shown in fig. 1 and then pushed forward to fully insert it into the nozzle 14 as shown in solid lines in fig. 1 until the tapered portion 20 of the wall 18 of the cartridge 12 abuts the cartridge abutment surface 26 in the forward end of the nozzle 14.

One advantage of the present invention is that it allows cartridge 12 to be pre-filled with an injection solution and then stored at any suitable location, such as in a manufacturing facility, hospital or other medical facility, pharmacy, ambulance, or in the residence of a patient requiring medication. Alternatively, cartridge 12 may be prefilled and stored in position within nozzle 14 and may be ready for insertion into a needle-free injector of the type shown in fig. 3, generally designated by the numeral 32.

U.S. patent No.5,399,163 to Peterson et al discloses a needle-free injector 32 that typically employs a cartridge/nozzle assembly 10, although the assembly 10 may be used in a wide variety of other needle-free injection systems. The Peterson' 163 patent is incorporated herein by reference. As shown in FIG. 3, the cartridge/nozzle assembly 10 is mounted to the forward end 34 of the injector 32 by a series of evenly spaced lugs 36, typically three such lugs being disposed at 120 degree intervals around the circumference of the nozzle 14. Lugs 36 in the nozzle 14 are aligned to pass through corresponding spaces 38 provided in the forward end 34 of the injector 32. The cartridge/nozzle assembly 10 is then rotated to lock it in place such that the lugs 36 are disposed between the inner surface 40 of the front end 34 of the syringe 32 and a lug abutment surface 42 in the syringe 32. When cartridge nozzle assembly 10 is inserted into syringe 32, the forward end of pushrod 44 abuts a somewhat resilient teflon pad 45 mounted on the rearward end of plunger 24. Contact between the ram, the gasket 45 and the plunger 24 is completed before the lugs 36 reach the lug abutment surfaces 42 in the syringe 32. As cartridge 12 continues to be pushed into injector 32, with lugs 36 disposed against lug abutment surfaces 42, fixed pushrod 44 slides plunger 24 forward, which in turn causes liquid injectate within cartridge 12 to move outlet valve 46 forward, allowing liquid to flow into recess 50 and toward injection orifice 52 (see FIG. 1). The amount of liquid that flows through outlet valve 46 during insertion of cartridge 1 within syringe 32 may be controlled by the length of pushrod 44 relative to lug abutment surface 42.

As best shown in FIG. 4, outlet valve 46 is disposed adjacent the inner surface of tapered wall 21 in the forward end of cartridge 12. The valve 46 may be generally constructed of butyl rubber or other resilient material capable of being sterilized prior to insertion into the cartridge 12. As shown in fig. 4, the valve 46 is designed to fit snugly over the forward end of the cartridge 12. As best shown in fig. 6-10, a middle portion or body 58 of outlet valve 46 is generally circular in cross-section and is sized to fit snugly within tapered wall 20 of cartridge 12. The rear portion of outlet valve 46 includes four circular slots 56, which slots 56 extend rearwardly from a centrally disposed body portion 58 of outlet valve 46. Front end 51 of outlet valve 46 includes forwardly extending portions 62 that extend axially from body 58 of outlet valve 46 to form two perpendicular valve passages 64.

In the preferred embodiment, the outer diameter of the outlet valve is slightly larger than the inner diameter of the tapered wall 21, typically 2.667mm (0.105 inch) outer diameter of the outlet valve, and 2.4892mm (0.098 inch) inner diameter of the tapered wall. This difference in size, along with some elastic properties of PTFE (polytetrafluoroethylene) or other material forming outlet valve 46, causes a friction fit to exist at the forward end of cartridge 12. However, once water pressure is applied to outlet valve 46, such as when cartridge/nozzle assembly 10 is pushed into place in needle-free injector 32 with ram 44 held stationary within the injector, outlet valve 46 is pushed to the forward, initially pressurized position shown in FIG. 5, with the forward end of outlet valve 46 disposed against valve abutment surface 48 at the forward end of recess 50 in the forward end of nozzle 14. The abutment surface 48 generally comprises a surface or shoulder extending perpendicular to the longitudinal dimension of nozzle 14 and the direction of movement of outlet valve 46. The forward end 51 of outlet valve 46 generally includes a surface that compliments the shoulder of the abutment surface, which also extends perpendicular to the longitudinal dimension of the valve and the direction of valve travel. The forward end of the recess 50 terminates in an injection orifice 52 having a substantially conical orifice 54. The relative dimensions of the respective outlet valve 46, the inner surface of tapered wall 20 and recess 50 should be such that fluid can flow from the cartridge and around the outlet valve into the recess and possibly even out of the injection orifice 52.

Operation of the embodiment of FIGS. 1-10

When operated at the factory or at the user, cartridge 12 is inserted into nozzle 14 as shown in phantom in fig. 1 and then pushed forwardly and fully into the nozzle, as shown in solid lines in fig. 1, until tapered portion 20 of wall 18 of cartridge 12 abuts cartridge abutment surface 26 in the forward end of nozzle 14. Prior to installation of cartridge/nozzle assembly 10 into syringe 32, as shown in FIGS. 1 and 4, outlet valve 46 is inserted into and secured within throat 21 of cartridge 12 in its pre-initial pressure position. When the valve is in this position, fluid disposed within the cartridge is prevented from flowing out of throat 21 through body portion 58 of valve 46.

Because pushrod 44 within syringe 21 is held stationary, when cartridge/nozzle assembly 10 is inserted into a syringe 32, the pressure applied by plunger 24 to the fluid disposed within cartridge 12 moves outlet valve 46 into the forward initial pressurized position shown in fig. 5. Because outlet valve 46 includes slots 56, fluid within the cartridge is allowed to flow through the throat 21 of the cartridge and into recess 50 of the nozzle. Forward valve passage 64 in outlet valve 46 allows fluid to rush into recess 50 to displace any air in the recess, forcing that air out of orifice 54 and jet 52. So that the recess, the bore and the nozzle bore will be completely filled with injection liquid. This may cause some injectate to drip out of the injection orifice, but because the amount of drip is small, it can be ignored. It is important that all air is expelled from the forward end of the nozzle 14. This makes it possible to accurately measure the amount of injection liquid to be injected into the patient, which would not be possible if an unknown amount of air were in front of the nozzle. This also allows the pressure to be accurately predetermined, which is likewise not possible if an unknown amount of air is in front of the nozzle.

The step of inserting the cartridge/nozzle assembly 10 into the injector 32 is typically performed immediately prior to injection. Thus, when the assembly is in place, the needle-free injector 32 may be actuated, pushing the plunger 44 and plunger 24 forward, thereby driving injectate through the groove 56 in the outlet valve 46, around the body 58 disposed in the recess 50, through the valve passage 64 and into the orifice 54 and jet orifice 52, and into the patient. Due to the configuration of outlet valve 46, throat 21 and the inner wall of recess 50, the pressure drop is very small as fluid is pushed out of the cartridge and out of injection hole 52.

FIGS. 11, 12A and 12B embodiment

Fig. 11, 12A and 12B illustrate another embodiment of a pre-filled cartridge/nozzle assembly, generally designated by the numeral 110. Instead of an outlet valve, the embodiment 110 includes a diaphragm 166 of resilient material designed to rupture open when a predetermined pressure is applied, as shown in fig. 12A and 12B. The diaphragm 166 generally has a weakened portion that can rupture. In the illustrated embodiment, the weakened portion takes the form of a notch 167 that extends almost, but not completely, 360 degrees around the internal throat 121 of the cartridge 112. The diaphragm 166 is typically retained by an aluminum seal 168, which is often used to assist in sealing the drug-containing cartridge.

In other respects, embodiment 110 is very similar to embodiment 10 in that it includes an O-ring 122 and nozzle 114, and it is typically pre-filled with injectate. The diaphragm 166 is designed to: when it is loaded into a needleless syringe, the membrane is broken open by slightly pushing the plunger (not shown) by the syringe plunger (not shown) as described above. With the burst membrane 166, the injectate flows into the recess 150 at the forward end of the nozzle 114, thereby displacing any air present and preparing the assembly for injection.

FIG. 13A and FIG. 13B embodiment

Fig. 13A and 13B illustrate another alternative embodiment of a cartridge/nozzle assembly, generally designated 210. This embodiment also utilizes an aluminum seal 268 as in embodiment 110, but it also includes an outlet valve 246. The outlet valve 246 includes a pair of radially extending wings 270, and these wings 270 are sandwiched under the aluminum seal 268 before a predetermined amount of pressure pushes the outlet valve 246 out of the internal throat 221 of the cartridge 212. When this predetermined pressure is reached, the wing 270 is pulled out of the seal and the valve is biased forwardly into the recess 250 of the nozzle 214 until it contacts the nozzle's abutment surface 248.

Outlet valve 246 is identical to outlet valve 46 described above in the cartridge/nozzle assembly 10 of fig. 1-10, except for the presence of wings 270. Thus, when outlet valve 246 is moved into the forward position as shown in fig. 13B, injectate is allowed to flow out of cartridge 212 and into recess 250 to displace any air present, thereby preparing assembly 210 for injection as described above.

FIGS. 14A-C example

The cartridge/nozzle assembly 310 of fig. 14A-C is identical to assembly 210, except that the wings 370 of the outlet valve 346 include several weakened portions. In the illustrated embodiment, these weakened portions take the form of a pair of notches 372. Thus, instead of wings 370 pulling out of engagement with seal 368 when cartridge/nozzle assembly 310 is installed in a needle-free injection system (not shown), the wings typically tear at notches 372, allowing outlet valve 346 to move to the forward position shown in fig. 14C. Otherwise, the cartridge/nozzle assembly 310 operates the same as the assemblies 10 and 210 described above.

FIGS. 15, 16A and 16B embodiment

The cartridge/nozzle assembly 410 of fig. 15, 16A and 16B is identical to the assembly 10 of fig. 1-10, except that the recess 450 of the nozzle 414 includes a plurality of evenly spaced ribs 474. In the illustrated embodiment, four such ribs 474 are included. As shown in fig. 16B, they are sized so that outlet valve 446 can fit snugly into recess 450. The channels 476 formed between the ribs 474 allow fluid to flow around the outlet valve 446 to the bore 52. Otherwise, cartridge/nozzle assembly 410 is constructed and operates in the same manner as assembly 10 of fig. 1-10.

FIGS. 17A and B embodiment

Fig. 17A and B illustrate another embodiment of a cartridge/nozzle assembly, generally designated by the reference numeral 510. The assembly includes a cartridge 512 and a nozzle 514. The cartridge 514 is pre-filled with injectate as described above and sealed with an aluminum seal 568 and an elastomeric membrane 566. A spike 578 is provided to pierce the membrane 566 when the cartridge is fully inserted into position within the nozzle as shown in fig. 17B. This is usually done shortly before injection. A plastic spike seal 580 is provided adjacent the spike to prevent leakage of the injectate. The assembly 510 may then be installed into a needle-free injection system as described above, displacing air to prepare the device for injection.

Otherwise, the cartridge/nozzle assembly is constructed and operates in the same manner as those described above.

The embodiment of fig. 18-22

Fig. 18-22 show another embodiment of a cartridge/nozzle assembly. The assembly, generally indicated at 610, includes a cartridge 612 and a nozzle 614. Fig. 18 shows assembly 610 threaded into needleless injector 632. Except for this threaded connection, syringe 632 is identical to syringe 32 described above. Also shown in fig. 18 is a contamination cap 633. Prior to use, this cap is positioned at the forward end of nozzle 614 to prevent any contamination of nozzle orifice 652 and the injectate contained within cartridge/nozzle assembly 610.

The contamination-resistant cover 633 is shown to be air-tight. However, it will be appreciated that this cap 633 will allow air and/or injectate to escape the nozzle orifice 652 when fluid pressure is applied. Thus, as will be explained below, when the cartridge/nozzle assembly is mounted to a syringe 632, air and some injectate will leak past the cap 633. Alternatively, the anti-contamination cap may include ribs (not shown) that allow the cap to be securely mounted to the front end of nozzle 614, but which facilitate the egress of air and injectate out of the nozzle during installation.

The cartridge 612 is typically formed of tempered glass and is pre-filled with a liquid injectate. Nozzle 614 is shown comprised of a high strength thermoplastic material, typically polycarbonate. The cartridge 612 includes outer walls 618 that are slightly tapered at a front 620 thereof. The tapered wall 620 converges such that an interior throat 621 is formed at the forward end of the cartridge 612. An O-ring 622 is provided adjacent the tapered end of the forward portion of the cartridge between the cartridge and the inner surface of the nozzle sidewall 630. Another description of the positioning of the O-ring 622 is: an O-ring is disposed between the outwardly facing surface of the cartridge (outer wall 618) and the inwardly facing surface of the nozzle, adjacent the rear end of the throat. In the illustrated embodiment, a step 628 is shown in the inner surface of the sidewall 630, providing a stop and a sealing surface for the O-ring 622. Thus, when the cartridge is in place within the nozzle, the O-ring 622 prevents or at least reduces the flow of injectate along the interface between the outer surface of the cartridge wall 618 and the inner surface of the nozzle sidewall 630, and can maintain the higher pressures required for proper needleless injection.

A plunger 624 is disposed within the wall 618 of the cartridge 612 and controls the flow of injectate out of the cartridge, as desired by the operator. The medicament is injected aseptically (in a sterile environment) at the factory, as shown in fig. 19, and the cartridge 612 is inserted into the nozzle 614, then pushed forward, and fully into the nozzle until the forward end of the cartridge 612 abuts the cartridge abutment surface 626 at the forward end of the nozzle 614. Cartridge abutment surface 626 is sometimes referred to herein as a laterally extending interface surface.

As best shown in FIG. 19, an outlet valve 646 is initially disposed within throat 621 adjacent the forward end of cartridge 612. In the illustrated embodiment, outlet valve 646 is a spherical structure that may be constructed of PTFE (polytetrafluoroethylene) or other elastomeric material suitable for storing medication and capable of being sterilized prior to insertion into cartridge 612. As shown in FIG. 19, outlet valve 646 is designed to fit snugly within the forward end of cartridge 612. Because valve 646 is spherical in configuration and, in the preferred embodiment, does not include any slots or holes therein, and is sized to fit snugly within the throat 621 of cartridge 612, it can be said to include a body portion that engages the walls of the cartridge throat 621 to prevent the flow of injectate out of the cartridge until valve 646 is pushed out of the cartridge throat.

In a preferred embodiment, outlet valve 646 has a diameter of 2.79mm (0.110 inch) and throat 621 has an inner diameter of 2.49mm (0.098 inch). This difference in size, along with some elastic properties of PTFE (polytetrafluoroethylene) or other material forming outlet valve 646, allows for a friction fit at the forward end of cartridge 612. In fact, outlet valve 646 may take a more elliptical configuration than that shown in FIGS. 18 and 19, giving a practical case where the inner diameter of throat 621 is smaller than the diameter of outlet valve 646. Once water pressure is applied to outlet valve 646, in the front portion of nozzle 614, outlet valve 646 is pushed out of cartridge throat 621 into valve-receiving cup 647 and forwardly against valve abutment surface 648 at the forward end of the valve-receiving cup. This typically occurs when the assembly 614 is threaded into the receiving threads of the syringe 632. This threading step causes plunger 624 to be pushed slightly in an outward or forward direction (toward the right in fig. 18), thereby also pushing outlet valve 646 in a forward direction from throat 621. The forward end of the valve-receiving cup 647 terminates in an injection orifice 652 having a substantially conical nozzle orifice channel 654. The valve-receiving cup 647 is sometimes referred to herein as a recess of the nozzle.

To facilitate the flow of injectate from the cartridge 612 through the injection orifice 652, a plurality of bypass channels 649a, 649b, and 649c are formed in the valve-receiving cup 647 and valve abutment surface 648. They are of sufficient size that when the outlet valve 646 is disposed anywhere within the valve receiving cup 647 or against the valve abutment surface 648, there is sufficient clearance between the valve and the channels to allow injectate to bypass through the channels, flow into the orifice channel 654 and out the nozzle orifice 652. In the preferred embodiment, where the outlet valve 646 has a diameter of 2.79mm (0.110 inch), the valve receiving cup typically has a diameter of 2.92mm (0.115 inch), a valve passage of 3.81mm (0.150 inch) as measured in diameter, or 1.91mm (0.075) inch from the center of the valve receiving cup to the edge of the passage. A configuration with three bypass channels 649a, 649b, 649c is used, each channel being typically 45 degrees in width and the channels being evenly spaced with their centerlines at 120 degrees to each other. Of course, other passageway configurations may be used or substituted with other configurations that allow fluid to flow through the outlet valve and into the bore.

When plunger 624 is advanced slightly in the forward direction, the pressure of the injectate fluid within cartridge 612 will push outlet valve 624 from throat 621 into valve-receiving cup 647 and against valve abutment surface 648. Thus, infusate fluid will fill valve receiving cup 647 and channels 649a, 649b, and 649c and nozzle orifice 654 and drip out of nozzle orifice 652. When the contamination cap 633 is in place, this will allow the injectate to leak out of the cap as the assembly 610 is threaded into place on the syringe 632.

When the device is ready to be actuated, the decontaminated cap 633 is removed and the syringe 632 is activated. This drives plunger 624 forward, driving injectate out of orifice 652 and into the patient (not shown).

In other respects, cartridge/nozzle assembly 610 is similar to the embodiment of FIGS. 1-10 described above.

Operation of the embodiment of FIGS. 18-22

The cartridge 612 is inserted into the nozzle 614 at the factory where sterile conditions are assured. During this installation, the cartridge 612 is pushed forward fully into the nozzle until the forward end of the cartridge contacts the cartridge abutment surface 626 in the forward end of the nozzle. This position is shown in fig. 19. Since the injection liquid is held in the glass cartridge, the assembly can be stored for a long time before use. It is typically stored in a sterile box or bag (not shown). A number of such stored cartridge/nozzle assemblies 610 may be provided to a patient. In this case, the outlet valve in the throat 621 tightly seals the cartridge, thereby preventing the injection liquid from leaking out of the cartridge and preventing the injection liquid from being contaminated. A contamination-resistant cap 633 (shown only in fig. 18 after the assembly is mounted on the syringe) helps to prevent contamination.

When the user is ready to administer the medication, the assembly 610 is removed from its case or sterile bag and screwed onto the front end of the syringe, which is shown in fig. 18 and indicated by reference numeral 632. When threaded, plunger 624 is advanced because injection ram 644 in the injector is stationary. This pushes the outlet valve 646 out of the cartridge throat 621 and into the valve receiving cup 647 and against the valve abutment surface 648. Thus, the injection liquid fills all the air space in the front end of the nozzle, thereby allowing air and some injection liquid to leak out of the cap 633.

When the cartridge/nozzle assembly 610 is in place, the device is ready for injection. Immediately prior to injection, the contamination cap 633 is removed from the nozzle 614, the nozzle is brought against the patient's skin, and the injector is actuated.

Otherwise, the operation of cartridge/nozzle assembly 610 is substantially the same as assembly 10 shown in fig. 1-20.

Changes and modifications may be made to the present invention without departing from the spirit and scope of the invention, which is intended to be covered by the appended claims.

Claims (16)

1. An assembly for a needle-free injection system, the assembly comprising:

a cartridge having a plunger disposed at a rearward end thereof and a forward portion including an interior with a throat, the cartridge further including a laterally extending interface surface;

a displaceable outlet valve initially disposed within the throat, the outlet valve having a channel-free valve body;

a nozzle for receiving a cartridge, the nozzle defining a rearward cartridge receiving portion and including a front portion defining a valve receiving portion having a plurality of channels and an injection orifice formed therein, the front portion being configured to receive the valve when the outlet valve is moved toward a forwardly disposed position such that when the outlet valve is moved from the throat into the valve receiving portion of the nozzle, the interior of the cartridge has fluid passing through the channels into the injection orifice, the nozzle further including a laterally extending interface surface abutting the cartridge interface surface; and

a seal disposed between the cartridge interface and the nozzle interface, the seal at least for reducing leakage of injectate between the nozzle interface and the cartridge interface.

2. The assembly of claim 1, wherein the cartridge throat is tapered and the sealing member is mounted adjacent the cartridge throat in a gap formed between the cartridge and the nozzle.

3. The assembly of claim 1, wherein the valve receiving portion of the nozzle is in the form of a recess with a valve abutment surface having said passage formed therein.

4. The assembly of claim 3, wherein the passage includes an axially extending portion located in a recess of the nozzle.

5. The assembly of claim 1, wherein the outlet valve has a smooth and regular surface.

6. The assembly of claim 5, wherein the outlet valve is cylindrical.

7. The assembly of claim 6, wherein the outlet valve is spherical.

8. The assembly of claim 7, wherein the outlet valve is resilient.

9. The assembly of claim 8, wherein the cartridge is formed of glass.

10. A needle-free injection device, the device comprising:

a cartridge having a plunger disposed at a rear end thereof and a front portion including an interior with a throat;

a displaceable outlet valve initially disposed within the cartridge throat, the cartridge further including an outwardly facing interface surface;

a push rod for selectively providing a driving force to drive the plunger in a forward direction;

a nozzle for receiving a cartridge, the nozzle defining a rearward cartridge receiving portion and including a forward portion defining and terminating in a valve abutment surface having a plurality of passages and an injection orifice formed therein, the forward portion being configured to receive the valve when the valve is moved toward a forwardly disposed position such that the valve is disposed against the valve abutment surface such that the interior of the cartridge has fluid passing through the passages and into the orifice, the nozzle further including an inwardly facing interface surface abutting the cartridge interface surface; and

a seal is provided between the cartridge interface and the nozzle interface for at least reducing leakage of injectate between the interfaces.

11. The assembly of claim 10, wherein the valve abutment surface is cup-shaped.

12. The assembly of claim 11, wherein the outlet valve is cylindrical at least at a forward end thereof.

13. The assembly of claim 12, wherein the outlet valve is spherical.

14. The assembly of claim 10, wherein the outlet valve is resilient.

15. A method for preparing a needle-free injection system, the method comprising:

selecting a glass cartridge with a plunger positionable in the rearward end and having a forward portion with an interior having a throat and with an outlet valve positionable in the throat, the cartridge further including a laterally extending interface;

positioning a seal on the cartridge rearward of the laterally extending interface;

positioning one of a plunger or an outlet valve within the cartridge;

filling the cartridge with an injection solution prior to positioning the other of the plunger or the outlet valve within the cartridge;

positioning the other of the plunger or the outlet valve within the cartridge;

selecting a nozzle comprising a rearward cartridge receiving portion and a forward portion defining a valve receiving portion, said valve receiving portion having a plurality of channels and an injection orifice formed therein, the forward portion being configured to receive the valve when the valve is moved toward a forwardly disposed position, the nozzle further comprising a laterally extending interface surface; and

the cartridge is mounted in the nozzle to form an assembly such that the interface is in abutment and the seal is disposed rearwardly of such abutment.

16. The method of claim 15, further comprising positioning a contamination-resistant cap in front of the spout.