Title of Invention

AN INJECTOR DEVICE AND A METHOD FOR DELIVERY OF LIQUID FROM A HIGH PRESSURE SOURCE

Abstract The present invention relates to an injector device for delivery of liquid from a high pressure, the device comprising a housing, a pressure chamber (2) comprising a pressure barrel (4) for accommodation of at least one piston therein and having a front end opening (6) for ejection of the liquid, the pressure chamber being of sufficient strength to sustain the liquid pressure. The device further comprises a storage chamber (16), separate from the pressure chamber, for the liquid or the liquid precursor components, and a conduit (22) between the pressure chamber and the storage chamber. A pressurizing mechanism (26) in the housing is arranged to apply force, directly or indirectly, on the piston in the pressure barrel to create said liquid pressure. The pressure chamber, the piston and at least a part of the conduit is arranged as a unit, wherein said unit and the housing have corresponding fitting parts allowing releasable attachment of the unit to the housing in a position permitting fluid connection between storage chamber and pressure chamber through the conduit and permitting the pressurizing mechanism to act on the piston. The present invention also relates to a method for delivery of liquid from a high pressure source.
Full Text

Title
Medical arrangement
Field of the invention
The present invention relates to an injector device, an injector unit pressure chamber and a method to perform the injection, according preambles of the independent claims.
Background of the invention
The principles of the present invention can be used in connection
injector requiring high level pressurization of the fluid to be inject
pressures may be needed for expelling high viscosity product, such
in oil, gelled, paste, amorphous or suspension form, e.g. for dental
to form slow release deposits in the body. Another major injector type.
high pressure is jet injectors for needle-less skin penetration of a perticular
liquid to be further discussed below. Although for convenience the
be described in terms of such jet injection, the invention shall not
restricted thereto but shall be understood to embrace other high pre
applications as well.
Jet injection apparatuses for hypodermic jet injection of medical liquid the skin surface or the mucous membrane of either humans or sufficiently high pressure to force the liquids to a predetermined the tissue beneath the skin surface or mucous membrane are known . since many years.
A multi-shot injector instrument employing the jet injection principles
from US-2,821,981. In this known instrument the fluid to be inje into a distal pressure chamber, an ampoule, from a proximal flu i chamber, e.g. in the form of a conventional syringe. One mechani transfer the fluid from the fluid chamber into the pressure chamber mechanism is then used to perform the injection. Non return valve
in the transfer bore to ensure that no back flow occurs. The mechine complicated structure of the injector instrument makes it rather e manufacture. Another drawback with this type of complicated m





An easy to use injector device is thus achieved having few movable parts and being easy to manufacture. The injector can be used for any high pressure injector application, can be pre-filled with medical and stored without deterioration of the medical and can be manufactured, stored and used under sterile conditions,
The injector device according to the invention is preferably intended for multi
dose injections.
It comprises a separate unit that includes a pressure chamber that is not reusable. The used unit is disposed after use and a new unit is attached to the injector housing when a new injection is to be given.
According to one preferred embodiment of the invention the liquid is pressed i; 11 According to another preferred embodiment the mechanism is responsible for dosing of the liquid medicine separate from the injection mechanism.
Information from the dosing unit regarding the dose volume transferred from the storage chamber via the liquid conduit into the pressure chamber is supplied to a control arrangement that in turn generates a control signal to a pressurizing mechanism, either as an electrical signal or as a mechanical movement. The control signal controls the movement of a piston in the pressure chamber so this it moves to a position where no air is left in the pressure chamber.
According to still another embodiment of the invention is a mechanical dosing unit used, e,g, by a rotating movement. This movement is stored in a mechanical . (or electronic memory) in order to be used by the pressurizing mechanism.
Short description of the appended drawings
Figures 1A-1C schematically illustrate different steps of the method according to
the invention.
Figures 2A and 2B illustrate the injector device according to a first embodiment

of the invention and Figures 2C and 2D illustrate a control arrangement in a
similar device.
Figures 3A-3E illustrate the injector device according to a second embodiment of
the invention.
Figures 4A and 4B show a cross sectional view of an alternative embodiment of
the by-pass section according to the invention.
Figure 5 illustrates the multi-dose injector device according to the invention.
Figure 6 shows the separate unit according to the present invention.
Figure 7A to 7F Illustrate a mechanism for dose setting, de-aeration and
injection, usable with the arrangement embodiment of Figure. 3,
Figure S illustrates schematically a prior art toothed plunger rod.
Figures 9A to 9D illustrates schematically a modified embodiment of that in
Figure 7, adapted for use with a toothed plunger rod.
Figure 10 shows schematically a modified ram sleeve for parallel arrangements.
Detailed description of preferred embodiments of the invention Corresponding features have the same reference numbers in all figures.
The basic steps in the method according to the present invention are schematically illustrated in figures IATI C.
A pressure chamber 2 comprising a pressure barrel 4 provided with a front end opening 6 for ejection of the liquid, an opening 8 for receiving liquid medicine 10 from a storage chamber (not shown) and a piston 12 sealingly inserted in the pressure barrel.
Figure 1A illustrates the loading step when a predetermined volume of liquid is inserted into the pressure barrel via the opening 8. The volume inserted is less than the volume of the pressure barrel above the piston 12. In this step the piston is in its loading position. The up-right position of pressure chamber in combination with surface tension prevents the transferred liquid to escape through the opening 6. As can be seeii from the figure the opening is close to the piston in order to be able to fill the pressure barrel from the bottom forcing the air,in an direction towards the opening,
-Figure 1B illustrates the sealing step where the piston 12 has been moved from the loading position to a sealing position and thereby seals off the opening S

from the storage chamber. The distance that the piston has moved is related to the volume of the liquid medicine such that substantially all air is expelled from the pressure chamber via the front end opening when the piston is in its sealing position. The figure shows a situation where a maximum dose of liquid is transferred into the pressure chamber. If the dose is smaller the piston is of course in a more distal position.
Figure 1C illustrates the ejecting step where a force is applied on the piston forcing it in a distal direction and thereby ejecting the liquid medicine through the front end opening as a liquid jet 14.
Figures 2A and 2B illustrate the injector device according to a first embodiment of the invention.
An injector device for delivery of liquid from a high pressure source is shown including a pressure chamber 2 comprising a pressure barrel 4 for accommodation of at least one pressure piston 12 inserted in the pressure barrel and having a front end opening 6 for ejection of the liquid 8, The pressure chamber being of sufficient strength to sustain the liquid pressure during the injection, and is preferably disposable and made from plastic. The device further comprises a storage chamber 16, separate from the pressure chamber, for the liquid or the liquid precursor components. The storage chamber is preferably made from glass and has a cylindrical shape. The chamber is provided with a membrane 18 at one end and a movable sealing storage piston inserted from the other end. The membrane and the piston enclose the liquid,
A conduit 22 is arranged between the pressure chamber and the storage chamber. The conduit is preferably an integral part of the pressure chamber and is provided with a needle 23 having a channel in connection with the conduit. The needle is adapted to penetrate the membrane 18 of the storage chamber in-order to establish a fluid connection between the storage barrel 8 and the pressure barrel 4.
The device also comprises a dosing unit 24, a pressurizing mechanism 26 and a control unit 28.
The dosing unit is adapted to apply a force on the storage piston inside the storage chamber in order to transfer a predetermined volume of liquid from the

storage chamber via the conduit into the pressure barrel. The volume that is transferred is dependent on the distance d moved by the storage piston. The dashed line indicates the position of the storage piston when a dose has been transferred.
The pressurizing mechanism is arranged to apply a force on the pressure piston in the pressure barrel to create the liquid pressure.
The pressurizing mechanism arranged to apply force, directly or indirectly, on the piston. The mechanism is only schematically indicated in the figures and may be e.g. spring loaded as disclosed in US-4,447,225. According to another principle is the injecting force generated by gas under pressure* These two principles are well known in the art. The pressure inside the pressure chamber during injection is in the order of 4000 psi (Pounds per square inch).
When a dose has been transferred into the pressure barrel information regarding the transferred volume is applied from the liquid transfer unit to the control unit 28. The control unit controls the pressurizing mechanism to first move the pressure piston in the pressure barrel from the loading position (figure 2A) to the
sealing position (figure 2B). This/movement is related to the volume so that when
/
the pressure piston 12 is in the sealing position substantially all air is expelled from the pressure barrel through the front end opening. After that the pressurizing mechanism generates, on demand, the necessary force to expel the liquid through the front end opening. This is here illustrated as a forward movement of a plunger 17 with respect to the pressurizing mechanism 26.
Figures 2C and 2D illustrate a similar design with a slightly different layout of the rear control parts. The dosing unit 24 is equipped with a dose setting button 25 and any known arrangement can be used to transform a rotation and/or an axial displacement of the button 25 into a forward movement of a pusher 19 for storage piston 20, e.g. a screw and nut arrangement, for dosing of liquid through conduit 22 and into the pressure chamber 2. Figure 2C shows the device after that such a dose transfer has taken place but before de-aeration. Figure 2D shows the device after de-aeration. Between the Figures the pressurizing mechanism 26 has moved forwards with respect to the pressure chamber 2 and also with respect to the box containing the dosing unit 24 and the control unit 28, as evident from the different location of a connection 29 therebetween, but

plunger 17 has not moved forward with respect to the pressurizing mechanism 26. The control mechanism is arranged to give a larger forward displacement of the pressurizing mechanism at smaller dose transfer movements for button 25 and vice versa so that the de-aeration forward movement of pressurizing mechanism 26 is complementary to the dose volume transferred to the pressure chamber 2, After de™aeration the pressurizing mechanism can be triggered to perform the injection. The axial mobility of the pressurizing mechanism with stationary plunger facilitates design of this part, e.g. with a spring and trigger, as it need not contain any arrangements for de-aeration.
The pressure chamber, the piston inside the pressure barrel and at least a part of the conduit is arranged as a separate unit that preferably is disposable. The storage chamber, the pressurizing mechanism, the dosing unit and the control arrangement are arranged in a housing.
The separate unit and the housing have corresponding fitting parts allowing releasable attachment of the unit to the housing in a position permitting fluid connection between the storage chamber and the pressure chamber through the conduit and permitting the pressurizing mechanism to act on the piston.
Figures 3A-3E illustrates the injector device according to a second embodiment of the invention.
The figures 3A-3E shows a cross sectional view of the pressure chamber 2 comprising a pressure barrel 4 provided with a front end opening 6 and a piston 12 arranged inside the barrel. The pressure chamber further comprises a piston rod 30 with a central channel 32 connected to a needle 34, and a rear support 36. A by pass section 38 is further provided at the inner surface of the pressure barrel where the piston is located in its loading position. A part of the storage chamber 16 with the membrane 18 is also shown in the figure. A ram 40 (partly shown in the figure) is in mechanical connection with the pressurizing mechanism (not shown) and adapted to submit the force generated by the pressurizing mechanism to the piston via the support 36 and the piston rod 30. The ram is freely moveable in relation to the storage chamber* The support 36 preferably comprises a number of support arms, e.g. 3-5, at a proximal part of piston rod. The support positions the needle in a central

position of the pressure chamber and ensures that the needle is in a steady position when the needle penetrates the membrane of the storage chamber. The support is also a support for the ram 40 when moving the piston rod and the piston in a distal direction.
The by-pass section 38 may be arranged in many different ways. According to one preferred embodiment a number of traces or channels for the liquid are provided in the inner surface of the pressure barrel. According to another embodiment is the inner surface provided with means that causes deformation of the piston when passing, thereby ensuring that liquid can pass the piston. Persons skilled in the art are aware of many other alternative ways of arranging the by-pass section.
Figures 4A and 4B shows a cross sectional view of an alternative embodiment of the by-pass section. According to this embodiment the piston 12 is provided with a number of channels 13, e.g. 1-4, In the loading step of the procedure the channels provide a fluid connection between the central channel 32 of the piston rod 30. In the sealing step the piston rod 30 is in fluid tight connection with the piston and thereby seals off the channels (figure 4B).
Figure 3A shows the loading step of the method. A predetermined dose of liquid medicine is expelled from the storage chamber by the dosing unit (not shown). The separate unit comprising the pressure chamber, the liquid conduit, the piston and the piston rod is arranged in connection with the housing (not shown). The upper part of the piston rod is provided with a sealing member 42 that in the loading position engages the inner surface of the pressure barrel in order to achieve a fluid tight connection for the liquid conduit. The needle is inserted through the membrane 18 into the storage chamber. The dose is transferred from the storage chamber through the needle and the central channel of the piston rod and passes the piston in the space between the distal part of the piston rod and the by pass section 38 into the pressure barrel 4-
When the predetermined volume has been transferred into the pressure barrel control arrangement (not shown) receives information from the dosing unit related to the transferred volume and initiate the second step, the sealing step, where the piston is moved from the loading position to the sealing position.



parts described. This feature is made possible partly by the fact that with the invention it is not necessary to draw or aspirate liquid into the pressure chamber by a retraction of the piston but liquid can be injected positively into the pressure chamber since de-aeration can later be done.
The storage chamber may be a single chamber where the liquid medicine is stored. It may also be a two compartment (or multi compartment) chamber provided with a by pass section (or by pass sections) in order to prepare the liquid prior injection.
Different storage chambers may be provided containing different concentrations of liquid medicine. It is advantageous to use small dose volumes in that it is less painful to inject a smaller volume than a larger volume. If smaller injection volumes are used the concentration of the active substance in the liquid medicine must be higher.
Throughout the description of the present invention the high pressure jet generated by the device is arranged to penetrate the skin of a patient. However the basic principles of the invention is equally applicable when performing needle injection of liquid medicines having high viscosity, e.g. gels. If e.g, a gel is to be injected today by a needle syringe a needle having a comparatively large inner diameter must be used which might be very painful. According to an alternative embodiment of the present invention a hypodermic needle is attached in connection with the front end opening of the injector device. The connection is performed in a robust manner in order to withstand the pressure inside the pressure chamber during injection. The needle is preferably attached to the pressure chamber during the manufacture of the chamber, e.g. during a molding process. The injection procedure is the same as when performing a needle less jet injection as described above. By using a pressure chamber provided with a needle having a similar inner diameter as the front end opening of the pressure chamber a liquid having a high viscosity can be injected using a thinner needle than before. This is very advantageous in that it is less painful for the patient. The necessary pressure needed to perform the needle injection according to the alternative embodiment is inter alia dependent of the inner diameter of the needle and the viscosity of the liquid gel.

Typical maximum pressures in the pressure chamber are in general above 25 atm (2,5 MPa), often above 50 atm (5 MPa) or above 100 atm (10 MPa). Normally the pressures are below 1000 atm (100 MPa), often below 800 atm (80 MPa) or below 500 atm (50 MPa).
Figure 5 illustrates the multi-dose injector device according to the invention. The device comprises the housing 51 including indicator 53 indicating the size of the dose, adjustment control 55 for adjusting the dose size, a mechanism for preparing the injection 57 (controls the dosing unit and the pressurizing mechanism), a release trigger 59 that controls the pressurizing mechanism to generate the force needed for injection, an indicating window 61 and the separate unit 63.
Figure 6 shows the separate unit 63 in an enclosing cover 65 with a removable film 66 to maintain sterility. The separate unit 63 is adapted to be releasable attached to the housing when an injection is to be performed. Threads 67 are provided at the separate unit and corresponding threads are arranged on the inner surface of the distal end of the housing. The unit 63 is unscrewed and disposed after use.
Figure 7A to 7E illustrate a mechanism for dose setting, de-aeration and injection, usable with the arrangement embodiment of Figure 3, which here corresponds to the front parts in the Figure, The device shown, generally designated 700, can be said to include a disposable part 701 and a reusable part 702 containing the mechanism and the storage chamber. With the same reference numbers as in Figure 3 the disposable part 701 includes the pressure chamber 2 with pressure barrel 4 and piston 12 and opening 6 as well as piston rod 30 with central channel 32, rear needle 34 and support plate 36. The reusable part 702 can be said to include a housing 710 embracing a storage chamber 720 and the mechanism to be further described. The housing 710 has a front inner thread 711 for engagement with an outer thread on disposable part 701, allowing removal of a used disposable part and attachment of a fresh, during which operation the needle 34 penetrates the storage chamber membrane. The storage chamber 720, here shown with a bottleneck front, comprises a penetration membrane 722, a storage piston 724 and an open rear

end 726. The mechanism can be said to include an injection unit 730, better seen in Figure 7F, comprising a ram 731 sleeve, surrounding the storage chamber 720, having a front flange 732, arranged for push cooperation with piston rod support 36, and a rear flange 733 to be affected by a spring 736. The ram sleeve is telescopically arranged in a surrounding ram support 734, havir g a support flange 735 for the spring 736. The ram is axially movable with respect to the ram support and the spring is biased to propel the ram forwards, and thereby also the piston rod 30, with sufficient force to create the pressure necessary for injection. A trigger button 737 is schematically illustrated and being arranged to normally lock the ram 731 and the ram support 734 with respect to each other but when pushed allows forward movement of the ram under action of the spring. The entire injection unit 730 is arranged axially movable in the housing 710 to allow forward movement under the de-aeration step, before triggering of injection, and the housing has a slit 712 for accommodation of the externally accessible trigger 737 during such an axial movement of the injection unit 730. The mechanism can be said to further include a de-aeration unit 740, arranged to move the injection unit 730 forwards during the de-aeration step, thereby also moving the piston rod 30 forwards. The de-aeration unit 740 comprises an axially movable transition element 741, having a front end 742, for cooperation with the ram support flange 735 when pushing the injection unit forwards, and a rear push flange 743, for cooperation with a pusher to be described, and a central hole 744, allowing free axial passage around a control drum to be described. The mechanism can also be said to include a liquid transfer unit 750, arranged for displacement of storage piston 724, to affect liquid transfer from the storage chamber 720 via needle 34, central channel 32, and by-pass 38 into the pressure chamber 2, as described in relation to Figure 3. The liquid transfer unit 750 comprises a rotationally arranged threaded plunger 751, which cooperates with a correspondingly threaded nut 752, which is axially and rotationally stationary with respect to the housing, so that a rotation of the plunger causes the plunger to move axially* The rear part of the plunger is inserted in and cooperates with the control drum, to be described, with a non-rotational connection (not shown), e.g. anon-circular connection, so that a rotation of the drum imparts a rotation on the plunger and with a one-way connection (not shown), e.g. a pawl and ratchet arrangement, so that the plunger will only rotate in the one direction causing it









In Figures 9C and 9D an arrangement similar to that of Figure 7 is shown and the following description will focus on the differences. A plunger 951, as described in relation to Figures 9A and 9B, is centrally arranged in the mechanism shown and has the same purpose of transferring liquid from a storage chamber to a pressiire chamber as described in relation to Figure 7. Tiie plunger 951 is axially movable but rotationally locked in relation to the housing 910 in any manner known per se, e.g. by a part connected to the housing permanently keying in to the plain parts of the plunger. For similar purposes as explained in relation to Figure 8, a set of three stationary latches 953 is arranged to allow forward but not rearward movement of the plunger. These latches are permanently engaged with the plunger although preferably an arrangement can be present for release in connection with plunger retraction at cartridge replacement, e.g. by allowing rotation of the plunger for release from both the stationary latches and feeding latches when the knob is in its rear position or allowing rotation of a support for the stationary latches when the knob is in its pushed, forward, position. Similarly three feeding latches 954 are arranged on a platform 955, which can both be reciprocated axially and rotated enough to either bring the feeding latches to the shown teeth engagement or to the plain parts. The platform 955 is connected to a plunger driver 956 in such a manner that it moves with the plunger driver in the axial direction but is free to rotate in relation to the plunger driver, e.g. by a bearing type attachment. To be further explained the plunger driver is driven in the axial direction by a control knob, in the shown embodiment by having a gear wheel 957 rotating between a fixed toothed housing rail 911 on the housing and a corresponding toothed knob rail on the control knob, the arrangement giving the plunger driver half the displacement of the control knob and allowing doubled pitch (axial step for one revolution) with reduced friction for the drum, to be explained. A spring 959 biases the plunger driver towards a retracted position. The platform 955 is also connected to an extension 967 of a drum 961 by which rotation can be imposed on the platform to move feeding latches 954 between the toothed parts 952 and the plain parts 958 of the plunger 951 but the extensions can move freely in the axial direction with respect to the platform. These components can be said to be part of a control unit 960 having the same purpose as in the embodiment of Figure 7, i.e. to secure sequence of liquid transfer followed by de-aeration. In the present embodiment the drum 961 can both rotate, to engage or disengage

latches 954 as described, and move axially to allow the extensions 967 to affect a de-aeration unit (not shown). The drum is preferably hollow to accommodate part of the plunger, The drum has a track 962 with a helical part 963? a knee 964, a first straight part 965 connected to the helical part at a second knee 969 and a second straight part 966. The track co-operates with a track follower 968, in this embodiment attached to the housing. When the drum is moved in the axial direction the track follower will secure a first straight movement in the track first straight part 965, with the feeding latches 954 engaged to push the plunger forwards. When the follower 968 enters into the track helical part 963 it will impose a rotation on the platform 955 to disengage the feeding latches from the plunger. Preferably the pitch of the helical part is adapted to the pitch of the inclined teeth 952 of the plunger so that disengagement can take place without axial movement of the plunger- In the present embodiment the helical part pitch is about double that of the plunger teeth pitch because of the speed and movement reduction in the gear wheel 957 system, However, it is also possible to have a slightly higher pitch on the helical part to create a liquid bleeding during disengagement, e.g. to give a fixed volume overdose independent of dose set for example to fill out dead space in the liquid transfer channel parts. Alternatively a lower pitch can be used to facilitate release of the latches. The helical part pitch should be non-locking although it is possible to fine-tune the overall friction in the system so that a locking occurs at high reaction forces, e.g. to secure that any overpressure must even out before release of the feeding latches is possible. The pitch of the plunger teeth can be non-locking but is preferably locking, to stabilise the plunger positions. When the follower reaches the knee 964 the feeding latches are disengaged and further movement in the second straight part 966 will take place without moving the plunger forwards. As in the embodiment of Figure 7 the knee 964 is axially located where de-aeration begins, in the present embodiment where extensions 967 comes into contact with parts moving the piston in the pressure chamber. Further forward movement of the drum, with the follower in the second straight part 966 of the track, will perform de-aeration by moving the piston in the pressure chamber. Since follower movement in the helical part 963 does not, or only slightly, displace the plunger the movements in the first straight part 965 and the second straight part 966 become complementary for a given constant stroke length of the drum, such that a short movement in the first straight part (small liquid dose) corresponds to a







parallel to the longitudinal direction of the delivery chamber, e.g. as described in US 5501673. They could also being arranged in an angle to the longitudinal direction, e.g. as described in US 5716338. The number of channels is chosen in dependence of the amount of liquid to be transferred, preferably in the order of 1-15. Many further different ways to arrange the by-pass section are known from the prior art. It is important that not too many channels are arranged due to the volume of liquid that remains in the channels when the liquid is transferred. It is also suitable to reduce the dead volume held between any circumferential ridges. on the pistons by keeping the difference small between the diameter through the ridges and through the main body of the piston respectively. According to an alternative embodiment is the shape of the inner surface of the by pass section such that the piston is deformed when passing the section and thereby allows liquid to pass from the storage chamber into the pressure chamber e.g. as described in US 5472422 and US 5817055.
The different steps performed is basically a three step procedure comprising a transfer step where the liquid is transferred from the storage chamber into the pressure chamber, a step for removing air from the pressure chamber and an injection step. The liquid transfer and the de-aeration steps are preferably performed fairly slowly and under low pressure compared with the pressurizing step,.not to induce glass breakage, plunger overshooting in the by-pass, liquid foaming or liquid spraying through the opening. Only the injection step has to be performed under high pressure.
Both during the transfer step and during the air removing step the device is preferably held in a somewhat upright position, i.e. the front end opening of the pressure chamber above horizontal, aslant or substantially facing upwards, in order to prevent the liquid to pour out,
The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appended claims.



Claims
1. An injector device for delivery of liquid from a high pressure source, the device comprising
a) a housing,
b) a pressure chamber (2) comprising a pressure barrel (4) for accommodation. at least one piston therein and having a front end opening (6) for ejection of the liquid, the pressure chamber being of sufficient strength to sustain the liquid pressure,
c) a piston (12) inserted in the pressure barrel,
d) a storage chamber (16), separate from the pressure chamber, for the liquid of the liquid precursor components,
e) a conduit (22) between the pressure chamber and the storage chamber,
f) a pressurizing mechanism (26) in the housing arranged to apply force, direct1y or indirectly, on the piston in the pressure barrel to create said liquid pressure, characterized in the improvement comprising,
i) that the pressure chamber, the piston and at least a part of the conduit is arranged as a unit, and
ii) that the unit and the housing have corresponding fitting parts allowing releasable attachment of the unit to the housing in a position permitting fluid connection between storage chamber and pressure chamber through the condur and permitting the pressurizing mechanism to act on the piston.
2. Injector device according to claim 1,characterized in that said piston in said pressure chamber is adapted to be moved from a medicine loading position where the liquid medicine is loaded into the pressure chamber from the storage chamber via said liquid conduit to a sealed position where the liquid conduit is closed.
3. Injector device according to claim 2,characterized in that air inside the pressure chamber is expelled when the piston is in the sealed position.
4. Injector device according to claim 3, characterized in that said device further comprises a control arrangement that in dependence of the

volume transferred from the storage chamber to the pressure chamber controls the movement of the piston from the loading position to the sealing position so that substantially all air is expelled from the pressure chamber.
5. Injector device according to any preceding claim, characterized in that said device further comprises a dosing unit arranged to transfer an adjustable volume of liquid from the storage chamber into the pressure chamber.
6. Injector device according to any preceding claim, characterized in that the volume of liquid medicine stored in the storage chamber represents a plurality of injection doses.
7. Injector device according to any preceding claim, characterized in that the conduit comprises a by-pass section allowing liquid passage around the piston
8. Injector device according to any preceding claim, characterized in that the storage chamber is in fixed position relative the housing.
9. Injector device according to any preceding claim, characterized in that the pressurizing mechanism acts on the piston via a piston rod which can be separated from the piston to create part of the conduit and that the conduit comprises a needle attached to the piston rod for movement therewith,
10. Injector device according to claim 9, characterized in that said piston rod is provided with a central channel for transfer of liquid from the storage chamber to the pressure chamber.
1L Injector device according to claim 10, characterized in that said piston rod is provided with a needle having a channel in connection with said central channel in order to penetrate a sealing membrane of said storage chamber,
12. Injector device according to any of claims 9-11, characterized in

that the distal part of the piston rod is provided with a sealer, preferably made from resilient rubber, that in the loading position engages the inner surface of the pressure barrel in order to achieve a fluid tight connection for the liquid
conduit.
13. Injector device according to any preceding claim, characterized in that said separate unit is disposable.
14. Injector unit adapted for releasable attachment to an injector housing for delivery of liquid from a high pressure, the unit comprising
a pressure chamber with a pressure barrel for accommodation of at least one piston therein and having a front end opening for ejection of the liquid, the pressure chamber being of sufficient strength to sustain liquid pressure,
a piston inserted in the pressure barrel, and
a conduit between the pressure chamber and a storage chamber, that when in the releasable attachment to the housing in a position permitting fluid connection between tire storage chamber and the pressure chamber through the conduit and permitting a pressurizing mechanism to act on the piston.
I 5. Injector unit according to claim 14, characterized in that the pressurizing mechanism acts on the piston via a piston rod in the pressure chamber which can be separated from the piston to create part of the conduit and that the conduit comprises a needle attached to the piston rod for
movement therewith.
15. Injector unit according to claim 15, characterized in that said
piston rod is provided with a central channel for transfer of liquid from the
storage chamber to the pressure chamber.
17. Injector unit according to claim 16, characterized in that said piston rod is provided with a needle having a channel in connection with said central channel in order to penetrate a sealing membrane of said storage
chamber.
IS. Injector unit according to claim 17, characterized in that the

distal part of the piston rod is provided with a sealer, preferably made from resilient rubber, that in the loading position engages the inner surface of the pressure barrel in order to achieve a fluid tight connection for the liquid conduit
19. Injector device according to any of claims 1-13 or an injector unit accordinglV to any of claims 14-18, characterized in that said fitting parts comprises a corresponding screw and thread.
20. Injector device according to any of claims 1-13 or an injector unit according to any of claims 14-18, characterized in that said fitting connection between the unit and the housing is achieved by a clamping connection.
21. A method for delivery of liquid from a high pressure source, the method comprising the steps of

a) confining the liquid, or the liquid precursor components, in a storage chamber,
b) transferring the liquid from the storage chamber to a pressure chamber, initially containing gas, the pressure chamber comprising a pressure barrel of substantially constant cross-section for accommodation of at least one piston therein and having a front end opening for ejection of the liquid, the pressure chamber being of sufficient strength to sustain the liquid pressure, and
c) pressurizing the pressure chamber by action on the piston in the pressure barrel to create the liquid pressure,
characterized in the improvement comprising the steps of
i) transferring the liquid from the storage chamber to the pressure chamber to
only partially fill out the pressure chamber with liquid,
ii) after step i) moving the piston forwards with respect to the pressure chamber
to substantially displace the gas therein through the front end opening and
hi) after step ii) pressurizing the liquid in the pressure chamber for delivery of
liquid through the opening.
22. Method according to claim 21,characterized in that before step i) components are mixed in the storage chamber to create the liquid.
23. Method according to any of claims 21-22, characterized in that



a conduit (22) between the pressure chamber and the storage chamber,
f) a pressurizing mechanism (26) in the housing arranged when triggered to apply force, directly or indirectly, on the piston in the pressure barrel to create said liquid pressure,
characterized in the improvement comprising,
i) a liquid transfer unit arranged to move a liquid dose from the storage chamber
through the conduit to the pressure chamber, and
ii) a de-aeration mechanism arranged to move, directly or indirectly and with the
pressurizing mechanism not triggered, the piston forwards a stroke distance at
least corresponding to the volume not occupied by the liquid dose in the
pressure chamber.
31. The device of claim 30, characterized in that the de-aeration mechanism is arranged in parallel with the pressurizing mechanism
32. The device of claim 30, characterized in that the de-aeration mechanism is arranged in series with the pressurizing mechanism.
33. The device of claim 32, characterized in that the de-aeration mechanism is arranged between the piston and the pressurizing mechanism.
34. The device of claim 33, characterized in that the de-aeration mechanism is arranged to move the piston by elongating between the the piston and the pressurizing mechanism.
35. The device of claim 31, characterized in that the de-aeration mechanism is arranged to the rear of the pressurizing mechanism.
36. The device of claim 35, characterized in that the de-aeration mechanism is arranged to move the piston by elongating between the the housing and the pressurizing mechanism.
37. The device of claim 36, characterized in that the de-aeration mechanism is arranged to move the piston forwards by moving the pressurizing mechanism forwards.

33. The device of claim 30, characterized in that the de-aeration mechanism is arranged to move the piston by activation of stored energy.
39. The device of claim 30, characterized in that the de-aeration mechanism is arranged to move the piston by manual energy,
40. The device of claim 30, characterized in that the pressurizing mechanism is arranged to move the piston by activation of stored energy e.g. stored in a.mechanical spring or pressurized gas.
41. The device of claim 30, characterized in a control arrangement limiting the piston stroke distance imposed by the de-aeration mechanism.
42. The device of claim 41,characterized in that the stroke distance is variable.
43. The device of claim 42, characterized in that the stroke distance is variable as a function of the liquid dose moved to the pressure chamber.
44. The device of claim 43, characterized in that the function sets the stroke distance substantially to a constant length (L) minus the axial height (D) of the liquid dose when in the pressure chamber.
45. The device of claim 43, characterized in that the control arrangement is arranged to be affected by the liquid dose volume for setting the variable stroke distance.
46. The device of claim 43, characterized in that the control arrangement is designed to prevent activation of the de-aeration mechanism until transfer of the liquid dose has taken place.
47. The device of claim 42,characterized in that the stroke distance is variable by variation of a dead run for a member arranged to affect, after the dead run, directly or indirectly, the forward movement of the piston.

48. The device of claim 47, characterized in that the member is arranged to affect during the dead run the liquid transfer unit to transfer the dose.
49. The device of claim 43, characterized in that the member is arranged to perform substantially the same total movement independent of the variation of the dead run set.
50. The device of claim 30, chara c terised in that the front end opening (14) is designed for formation of a liquid jet , witth a short needle having a length of about 1 to 3 mm or a hypodermic needle.
51. The device of claim 30, c h a r a c i e r i z c d i n that the front end opening is covered with a removable or breakable closure or sealing.
52. The device of claim 30, characterized in that the pressure chamber and storage chamber are made from different materials preferably plastic and glass respectively.
53. The device of claim 30, characterizedin that said storage chamber is a dual chamber storage chamber provided with by-pass section and at least an additional piston dividing the storage chamber into two sub-chambers.
54. The device of claim 30, characterized in that the device is arranged for multiple doses with larger space for liquid in the storage chamber than in the pressure chamber.
55. The device of claim 30, characterized in that the pressure barrel has a rear liquid transfer position for the piston in which piston position the conduit has fluid communication with ihc prssure barrel in front of the piston and front sealing positions for the piston, in which pis ton positions no fluid communication is present.

56, The device of claim 55,characterized in that a bypass arrangement is a present in the liquid transfer position allowing liquid to pass around the piston into the pressure chamber in front of the piston.

57. An injection device substantially as herein described with reference to the accompanying drawings.


Documents:

in-pct-2002-2064-che-abstract.pdf

in-pct-2002-2064-che-claims filed.pdf

in-pct-2002-2064-che-claims granted.pdf

in-pct-2002-2064-che-correspondnece-others.pdf

in-pct-2002-2064-che-correspondnece-po.pdf

in-pct-2002-2064-che-description(complete)filed.pdf

in-pct-2002-2064-che-description(complete)granted.pdf

in-pct-2002-2064-che-drawings.pdf

in-pct-2002-2064-che-form 1.pdf

in-pct-2002-2064-che-form 13.pdf

in-pct-2002-2064-che-form 18.pdf

in-pct-2002-2064-che-form 26.pdf

in-pct-2002-2064-che-form 3.pdf

in-pct-2002-2064-che-form 5.pdf

in-pct-2002-2064-che-other documents.pdf

in-pct-2002-2064-che-pct.pdf


Patent Number 212376
Indian Patent Application Number IN/PCT/2002/2064/CHE
PG Journal Number 07/2008
Publication Date 15-Feb-2008
Grant Date 03-Dec-2007
Date of Filing 12-Dec-2002
Name of Patentee PFIZER HEALTH AB
Applicant Address S-112 87, STOCKHOLM,
Inventors:
# Inventor's Name Inventor's Address
1 HJERTMAN, Birger Svardsliljevagen 186, S-162 43 Vallingby,
2 FRIDHOLM, Jonas Tunnlandsvägen 46, S-168 36 Bromma,
PCT International Classification Number A61M 5/30
PCT International Application Number PCT/SE2001/001145
PCT International Filing date 2001-05-22
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 0001893-7 2000-05-22 Sweden