Abstract:
A method and a needleless injection system for administering a medication. In order to simplify as far as possible the handling necessary for loading the injector with medication and thereby eliminate risks caused by a complex handling the method and system according to the invention provide loading of medication into a needleless injector device by means of a syringe prefilled with a medication, this loading step preferably including connecting the syringe to the injector device by means of a suitable coupling member or adapter and operating the syringe for transferring medication prefilled therein into the injector device. After this transfer the syringe and/or the coupling member or adapter are detached from the injector device, which is then ready to be operated for ejecting the loaded dosage of said medication from the injector device and thereby pass the selected dosage through the skin of an injection receiver.

Description:
FIELD OF THE INVENTION 
     The invention concerns a method for parenterally administering a medication. 
     The invention also concerns a needleless injection system for administering a medication. 
     The invention also concerns a coupling member and a kit suitable for performing a method according to the invention. 
     BACKGROUND 
     The International Patent Application published under No. WO 89/08469 describes a method and a system of the above mentioned kind. This known system comprises a needleless injector device, a vial coupler device and a transporter/loader device. The method of use of this known system comprises the following steps: 
     In a first step, one end of the vial coupler device has to be connected to a vial containing the medication to be administered, and this includes piercing a piercable closure of the vial with a cannula forming part of the vial coupler device. 
     In a second step, the opposite end of the vial coupler device has to be connected to the transporter/loader device in order to establish a fluidic connection between the interior of the vial and the interior of the transporter/loader device. 
     In a third step, the transporter/loader device has to be operated for transferring a certain amount of medication from the vial into the transporter/loader device, said amount passing through the vial coupler device. 
     In a fourth step the transporter/loader device has to be disconnected from the vial coupler and connected to the needleless injector device for transferring a certain amount of medication from the transporter/loader device to the needleless injector device. 
     In a fifth step the transporter/loader device has to be disconnected from the needleless injector device. Only after completion of this step is the needleless injector device ready for the intended use, that is, for administering the medication. 
     From the foregoing description of the method of use of the device described in the International Patent Application WO 89/08469, it can appreciated that these known method and system have the serious disadvantage that their use requires a complicated handling comprising several steps, and that corresponding risks result therefrom, in particular the risk of microbial contamination during the handling. Also misdosing (inaccurate amount of medication) is likely to occur. 
     SUMMARY OF THE INVENTION 
     The aim of the invention is therefore to provide a method and system for administering a medication and a needleless injection system which eliminate the above mentioned disadvantages, that is, to provide a method and system which make possible to load a needleless injection system with a minimum of handling, and thereby preventing the above mentioned risks. 
     According to a first aspect of the invention this aim is attained with a coupling member comprising: 
     (a) a first end configured and dimensioned to correspond to the shape of a discharge end of an needless injector device; 
     (b) a second end configured and dimensioned to correspond to and receive a luer tip of a syringe; and 
     (c) an inner surface configured and dimensioned to establish a fluidic communication between an interior portion of the needleless injector device and an interior portion of the syringe. 
     According to a second aspect of the invention this aim is attained with a kit comprising: 
     (a) a needleless injector device; 
     (b) a syringe having a luer tip; and 
     (c) a coupling member comprising: 
     (i) a first end configured and dimensioned to correspond to the shape of a discharge end of the needless injector device; 
     (ii) a second end configured and dimensioned to correspond to and receive the luer tip of the syringe; and 
     (iii) an inner surface configured and dimensioned to establish a fluidic communication between an interior portion of the needleless injector device and an interior portion of the syringe. 
     According to a third aspect of the invention this aim is attained with a method for parenterally administering a medication, comprising: 
     (a) providing a needleless injector device having a barrel portion, a gas storage portion, and an intermediate portion extending between the barrel portion and the gas storage portion; 
     (b) providing a syringe prefilled with a medication said syringe being suitable for needleless loading of the injector device with said medication prefilled in the syringe; 
     (c) loading t he medication prefilled in the syringe into a bore of the barrel portion of the injector device through an aperture in the barrel portion thereof; 
     (d) detaching the prefilled syringe from the injector device; and 
     (e) operating the loaded injector device to eject the dosage of medication contained there in from the injector device and thereby pass said dosage of the medication through the skin of an injection receiver. 
     According to a fourth aspect of the invention this aim is attained with a needleless injection system, comprising: 
     (a) a needleless injector device that is dimensioned and arranged as an integral unit to be grasped in the hand of a user, the device having a barrel portion, a gas storage portion, and an intermediate portion extending between the barrel portion and the gas storage portion; and 
     (b) a syringe prefilled with a medication, said syringe being suitable for loading the injector device with said medication prefilled in the syringe. 
     In a preferred embodiment such a system further comprises coupling means for connecting the prefilled syringe to the needleless injector device and thereby establishing a fluidic communication between the interior of the syringe and the interior of the injector device for the purpose of transferring a quantity of medication from the prefilled syringe into the needleless injector device. 
     The main advantage of the invention is that it makes possible a completely needleless loading of the needleless injector device with medication prefilled in the syringe in a most simple way which requires a minimum of handling and therefore prevents risks resulting from complicate handling necessary with prior art devices and methods. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described hereinafter with reference to the accompanying drawings wherein: 
     FIG. 1 shows a schematic representation of the components of a preferred embodiment of a needleless injection system according to the invention, 
     FIG. 2 shows separately the end part of the injector device  11  in FIG. 1 and a coupling member  16 , which is suitable for connecting that end part to the syringe  13  in FIG. 1, 
     FIG. 3 shows a schematic representation of the connection of injector device  11  and the syringe  13  by means of the coupling member  16 , before the syringe is operated for transferring the medication prefilled therein into the injector device  11 , 
     FIG. 4 shows a schematic representation of the connection of injector device  11  and the syringe  13  by means of the coupling member  16 , after the syringe has been operated and the medication prefilled therein has been thereby transferred into the injector device  11 , 
     FIG. 5 shows the syringe  13  and the coupling member  16  connected thereto after they have been detached from the injector device  11  after the transfer of the medication from the syringe into the injector device  11 , 
     FIG. 6 shows the injector device  11  ready for use after it has been loaded with the medication and has been detached from the coupling member  16  and the syringe  13  connected thereto. 
     FIG. 7 shows a perspective view of a needleless injector device constructed according to the invention. 
     FIG. 8 shows an enlarged cross sectional view of the injector device taken on line  2 — 2  of FIG. 7 with the device loaded and ready for firing, but with the safety on. 
     FIG. 9 shows another cross sectional view similar to FIG. 8 showing the injector device after firing with the safety off, the trigger depressed, and the dosage partially injected. 
     FIG. 10 shows another cross sectional view similar to FIG. 8 showing the injector device with the dosage fully injected, the trigger released, and the compressed gas discharging. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The subject invention will now be described in terms of its preferred embodiments. These embodiments are set forth to aid the understanding of the invention, but are not to be construed as limiting. 
     FIG. 1 shows a schematic representation of a needleless injection system according to the invention. The system comprises the following components: 
     a needleless injector device  11  that is dimensioned and arranged as an integral unit to be grasped in the hand of a user, the device  11  having a barrel portion, a gas storage portion, and an intermediate portion extending between the barrel portion and the gas storage portion; and 
     a syringe  13  prefilled with a medication  14 , said syringe being suitable for loading the injector device  11  with said medication  14  prefilled in the syringe. 
     In a preferred embodiment an injection system according to the invention further comprises a coupling member or adapter  16  for connecting the prefilled syringe  13  to the needleless injector device  11  and thereby establishing a fluidic communication between the interior of the syringe  13  and the interior of the injector device  11  for the purpose of transferring a quantity of medication from the prefilled syringe  13  into the needleless.injector device  11 . 
     As can be appreciated, in particular from FIG. 2, the coupling member or adapter  16  has a shape, which on one side matches the shape of an end part of the injector device  11  and on the opposite side matches the shape of the luer tip of the syringe  13 , so that this tip can simply be plugged in that side of the coupling member or adapter  16 . The side of the coupling member or adapter  16  which matches the shape of the injector device  11  is preferably adapted to be connected to that end part of the injector device  11  by a suitable mechanical connection, e.g. a screw or a bayonet type connection. As can be further appreciated, in particular from FIG. 2, the coupling member or adapter  16  has an inner shape which makes it possible to establish a fluidic communication between the interior of the injector device  11  and the interior of the syringe  13  when they are connected with each other by means of the coupling member or adapter  16 . 
     In a preferred embodiment, coupling member or adapter  16  is preassembled with needleless injector device  11 . This preassembled embodiment reduces the number of manipulations to be performed by the user and increases safety by reducing the risk of mismanipulation. 
     The components of an injection system according to the invention are preferably conserved in closed, suitable envelopes  12  and  15  respectively, which are only opened just before use of the components for their intended purpose. 
     The needleless injector device  11 , which is schematically represented in the drawings of this patent application is for example of the type described in the above mentioned International Patent Application WO 89/08469. Injector device is described below under the section “Injector device” with reference to FIGS. 7 to  10 . The barrel portion of the injector device  11  has a bore  29  for receiving medication to be injected by means of the injector device  11 . 
     A preferred embodiment of a method according to the invention for administering a medication is described hereinafter in particular with reference to FIGS. 3 to  6 . 
     To start with the user will of course first of all open the envelopes  12  and  15  and take therefrom the components of the injection system shown by FIG.  1 . Then the user will screw the coupling member or adapter  16  on one end of the injector device  11  and he will plug the luer tip of the syringe  13  prefilled with a medication  14  into the coupling member or adapter  16 . The resulting assembly of these components is shown by FIG.  3 . It should be noted that this assembly establishes a fluidic communication between the interior of the syringe  13  and the interior of the injector device  11 . 
     The next step is the transfer of the medication  14  prefilled in the syringe  13  into the bore  29  of the barrel portion of the injector device  11  through an aperture of that barrel portion. For this purpose the user presses the plunger  17  of the syringe  13  in the sense indicated by arrow  18  in FIG.  4  and thereby forces the medication to flow out of the syringe  13 , through the coupling member or adapter  16  and into the barrel of the injector device  11 . At the end of this step the barrel of the injector device  11  is thus loaded with medication  14 . 
     The next step is the detachment of the syringe  13  from the injector device  11 , for instance by unscrewing the coupling member or adapter  16  and thereby separating it from the injector device  11 . FIG. 5 shows the syringe  13  and the coupling member or adapter  16  and FIG. 6 shows the injector device  11  after this operation. 
     After the step just described injector device  11  is ready to be operated in the way described in detail in the above mentioned International Patent Application WO 89/08469 for ejecting said medication  14  from the injector device and thereby pass the medication through the skin of the receiver of the injection. 
     A selected amount of medication injected in this way is preferably determined by the amount of medication  14  contained in the prefilled syringe  13 . For this purpose, the entire amount of medication prefilled in the syringe  13  is transferred from the syringe  13  into the injector device  11 , so that—in contrast to the known method of transfer described for example in the above mentioned International Patent Application WO 89/08469—no measuring of the amount of medication by the patient is necessary. 
     The prefilled syringe  13  and the injector device  11  are both apt to contain the same medication volume of e.g. 0.5 milliliter. 
     Injector Device 
     According to International Patent Application WO 89/08469 the structure and the operation of injector device  11  are as follows: 
     Generally, the device  11  includes an integral unit  24  that is dimensioned and arranged to be grasped in the hand of a user. It is integral in the sense that it carries its own one-shot power source instead of being reloadable and reuseable. As an idea of size, the unit  24  may be about ten or eleven centimeters long and about one and one-half centimeters across at its widest point. Of course, these dimensions are not critical. 
     Preferably composed of an injected molded thermoplastic material, the unit  24  includes a barrel portion  25 , a gas storage portion  26 , and an intermediate portion  27 . The barrel portion extends from the intermediate portion  27  to a discharge end  28  of the barrel portion  25  and it defines a bore  29  (FIGS. 8-10) that extends from the intermediate portion  27  to an orifice or aperture  30  in the discharge end  28 . 
     The gas storage portion  26  defines a gas storage compartment  31  in which is disposed a compressed gas such as CO 2 . This may be introduced during manufacture by suitable means, such as through an opening that is then sealed with a plug, and the compressed gas is used as an energy source for injecting the selected dosage from the bore  29  through the aperture  30 . In other words, it released from the storage compartment  31  to propel the selected dosage out of the barrel portion  29 . 
     The intermediate portion  27  defines an expansion chamber or chamber  32  that is used for this purpose. Preferably, the chamber  32  is cylindrically shaped. The intermediate portion  27  and the chamber  32  extend between the gas storage portion  26  and the barrel portion  25 , and a piston  33  combines with a pushrod  34  to couple force from compressed gas entering the chamber  32  to a plunger  35  disposed within the bore  29 , the piston  26  having a size and shape conforming to the cross sectional size and shape of the chamber  32 . 
     Injector device  11  includes gas release means for releasing the compressed gas from the compartment  31  so that the compressed gas can flow into the chamber  32 . This is accomplished in the illustrated device  11  with a breakable member in the form of a hollow glass quill  36  that extends through the gas storage portion  26  as shown (FIG.  8 ), from an open end  37  in the storage compartment  31  a closed end  38  in the chamber  32 . It may be suitably bonded in this position. 
     The gas release means so formed is actuated by breaking off the closed end  38  or the glass quill  36 . Injector device  11  includes trigger means for enabling a user to actuate the gas release means, and this is accomplished in the device  11  with a trigger mechanism that includes a trigger  39  attached to the intermediate portion  27  for movement when depressed by the user. When depressed, a firing pin  40  presses against add breaks the fragile glass quill to release the compressed gas into the chamber  32 . The gas flows from the storage compartment  31  through the hollow interior of the glass quill  36 . 
     But in order to operate the trigger the user must first position a safety ring  41  (FIG. 7) in an off.position. The safety ring  41  circumscribes the intermediate portion  27  as shown in FIG. 7, and it is mounted for rotational movement so that a space  42  in the safety ring  41  can be moved into alignment with the trigger  39 . This is the off position in which the trigger  39  can be depressed to fire the device  11 , and it is indicated by alignment of a ridge  43  on the safety ring  41  with an indicator  44  provided for this purpose. The ridge also enhances user engagement of the safety ring  41 . 
     Unless the safety ring  41  is in the off position, the trigger  39  is blocked from being depressed. The safety ring  41  is shown blocking the trigger  39  in FIGS. 7 and 8, and in the off position in FIGS. 9 and 10. 
     Operationally, the user grasps the device  11  and removes any sterility cover that might be provided over the discharge end  28 , such as a cap member (not shown) that is arranged to be screwed onto a threaded end portion  45  of the barrel portion  25 , for example. The threaded end portion  45  may employ a two-start thread that mates with threaded portions on the above described coupling member  16 . 
     At this point in the operation, the plunger  35  is disposed fully forward in the bore  29  in the position shown in FIG.  10 . Using the above described coupling member  16  and syringe  13  which form suitable dose dispenser means, the user loads a selected dosage of medication through the aperture  30  into the bore  29 . This may be done with by attachment of coupling member  16  to the threaded end portion  45  of the barrel portion  25  (FIG.  7 ). 
     As the selected dosage is loaded into the bore  29 , it forces the plunger  35  away from the discharge end  28  to a position such as that shown in FIG.  8 . Preferably, at least a portion of the barrel portion  25  is sufficiently transparent to enable a user to visually discern the position of the plunger  35  relative to a plurality of graduations  46  provided on the barrel portion  25 . This enables the user to ascertain precisely how much medication has been loaded into the bore  29  so that the loading procedure can be stopped as soon as the selected dosage has been loaded. 
     FIG. 8 shows a position the plunger  35  might occupied when loading has been completed, the stippling between the plunger  35  and the aperture  30  representing the selected dosage of medication that has been loaded into the bore  29 . 
     At this point in the self-administration of the medication, the user turns the safety ring  41  to the off position. Next, the user places the discharge end  28  proximate the user&#39;s skin at a point where the medication is to be injected and depresses the trigger  39  to fire the device  11 . 
     This results in the firing pin  40  breaking the glass quill  36  so that the compressed gas rushes through the quill  36  into the chamber  32  as shown in FIG.  9 . In this regard, little transverse pressure is required to break the glass quill  36  so that a few ounces of pressure may be all that is needed to depress the trigger  39  sufficiently to fire the device  11 . 
     As the compressed gas rushes into the chamber  32 , it acts against a piston face  47  of the piston  33  (FIG. 9) and this drives the piston toward the bore  29  with the result that the pushrod  34  contacts the plunger  35  and drives it toward the aperture  30 . This action causes a plunger face  48  of the plunger  35  to act against the medication and force it out of the aperture  30  in a high pressure jet depicted by the arrow extending outwardly from the aperture  30  in FIG.  9 . 
     The plunger  35  may be composed of a rubber material, for example, and be configured conform to the bore cross section. Thus medication does not flow past the plunger  35  toward the piston  33 . In addition, the plunger face  48  is configured as shown to conform to the shape of the bore  29  at the aperture  30  so that no medication remains in the bore  29  after firing. 
     According to one aspect of injector device  11 , the piston face  47  has a larger surface area than the plunger face  48 . This surface area differential results in more pressure being applied to the medication than the compressed gas applies to the piston face  47 . This pressure amplification may be utilized to achieve an injection pressure at the aperture  30  of about 2,500-5,000 psi, for example, depending on the precise configuration employed, whereas the compressed gas might exhibit a pressure of about 840 psi at room temperature. 
     As the piston  33  moves toward the discharge end  30 , gas ahead of the piston  33  (between the piston  33  and the barrel portion  25 ) vents through an opening  49  provided for this purpose (FIG.  9 ). Thus, the opening  49  serves as vent means disposed intermediate the piston  33  and the plunger  35  for enabling gas to escape from a region ahead of the piston  33 . 
     After firing, the compressed gas discharges through a discharge port  50  provided around the firing pin  40  (FIG.  10 ). This may be a hole through which the firing pin  40  extends. However, the discharge port  50  is sealed momentarily when the user operates the trigger  39 . This delays the escape of the compressed gas from the chamber  32  until the piston  33  has been driven substantially all the way to the fully fired position shown in FIG.  10 . 
     The delay is accomplished by utilizing an O-ring seal  51  disposed in the position shown in FIGS. 8 and 10 so that when the trigger  39  is depressed, the trigger  39  presses against the seal  51  to seal the discharge port  50 . The seal  51  may be composed of a know medical grade elastomeric material for this purposes. When the trigger  39  is released, it disengages the seal  51  to open or unseal the discharged port  50  so that the compressed gas can escape. 
     Other means may be used for delaying the escape of compressed gas through the discharge port  50 . For example, a tapered firing pin may be provided along with a discharge port having a mating taper so that the firing pin wedges into the discharge port momentarily during firing. 
     Although preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.