HK1012590B - Injection device - Google Patents

Description

The invention relates to a device for introducing an active substance solution into a patient with means for attaching the device to the body surface and a needle for inserting into the skin or underlying tissue and for administering the active substance solution.

In the context of preparing a patient for an operation, etc., a venous access is usually created today, to which injection devices can be connected if necessary. However, in the field of follow-up, therapy and prevention, this method is often associated with disadvantages, the most serious of which are mentioned. The insertion of cannulae can only be done by trained medical personnel. Patients themselves are in most cases not able to do so, so self-medication with drugs that are injected is not possible.

For the patient's convenience, and especially to facilitate self-medication, wearable devices have been developed that combine a needle and a reservoir for the active substance solution, for example EP-A-272530, a portable device for subcutaneous or intradermal injection of a liquid active substance consisting of a storage container, a needle to be connected to it, a pump to empty the container through the needle and a fixing device, whereby the needle is inserted into the patient's skin by means of a drive device.

Devices of this type, which have an active substance reservoir as an integral part, have the disadvantage of requiring a separate device for each active substance formulation and the limitation of the volume of active substance in these devices prevents their use for a number of applications.

Another device for the administration of an active substance to a patient is described in US-A-4,632,671. The device shown in this document is used to fill or, if necessary, empty a reservoir implanted in the patient. The patient's uncomfortable frequent insertion of a needle is avoided by a needle that is placed once and is used repeatedly for a long time. This would be unsuitable for the administration of active solution into the skin or subcutaneous tissue.

The purpose of the invention is therefore to provide a device that provides a high level of patient comfort while providing the greatest possible flexibility and safety for intradermal and subcutaneous injections.

According to the invention, this is achieved by a device as claimed in claim 1.

The following illustrations describe examples of the invention.

Figures 2.3 and 3 show different designs of injection devices.

Figures 1, 4 and 5 show embodiments, each on average, which are outside the scope of the claim but serve to illustrate the invention.

The device shown in Fig. 1 has a roughly conical case 1 with a concentric bore 2 consisting of four areas with larger diameters from bottom to top. The base of the case has a concentric protrusion 3. The part of the base surrounding the protrusion 3 is covered with an adhesive layer 4 to attach the device to a patient's body part, the material and thickness of which are selected mainly for comfort and safe holding of the device. Under this aspect, an adhesive foam was selected for layer 4. The front surface of the protrusion 3 is also covered with a thin adhesive layer 5 which is used mainly to fix adhesive. However, for this purpose it is possible to fix the skin 5 and 4 layers of adhesive material, which is proportionately stiff.

A Luer access 6 is fitted at one point of the housing to connect the device to a conveyor pump for a solution of active substances and via this to a reservoir. A narrow channel 7 leads from the Luer access to the central borehole. O-rings 8 are inserted into corresponding ring nuts on the inner wall of the borehole above and below the entrance of the channel 7 into the borehole.

The cannula 9 is a thin steel capillary approximately 200 μm in diameter with a slanted cutting edge. The cannula is held in a cannula holder 10 The cannula holder 10 is a concentrically and axially displacement-able element in the bore 2 shown in its upper end position. In its lower end position the lower forehead surface of the cannula holder rests on the crest formed by the transition from the narrowest area of the bore 2 to its next largest. The cannula 9 then extends through the angel-permeable area of the bore 2 and through the adhesive layer 5, e.g. in the skin of a patient's tissues.

The cylindrical side of the canister holder 10 has an extending channel 11 inside it, the end of which is opposite the cut-off end of the canister 9 and the channel 11 is opposite the channel 7 in housing 1 at the lower position of the canister holder.

The cannula holder has a guide flange 12 the diameter of which is the inner diameter of the third borehole. On its upper surface, the cannula holder 10 has a hollow cylindrical wall 13 with a circular coil on its inner side at its upper end. The wall 13 interacts with the coil with the holding and firing mechanism to be described below.

In the uppermost part of bore 2 with the largest diameter, a restraint and release mechanism 14 is used to hold the canister holder 10 in its upper end position and to allow its displacement to the lower end position by triggering it.

The holding and release mechanism 14 consists of two axially moving parts, the lower of which consists of a ring-shaped plate 15 and wall segments 16 protruding downwards at its central opening, essentially forming a hollow cylindrical shape.

The wall segments 16 have a conical section on their outer surfaces which forms the transition from an upper smaller to a lower larger axis. On this section the wall 13 is placed, which keeps the cantilever 10 in its upper end position. On their inner side the wall segments 16 also have a section in which a spreading flange 19 intervenes, which will be described below.

The upper part of the holding and release mechanism 14 consists of a trigger press 18 in the shape of a mushroom, at the lower end of which the aforementioned discharge flange 19 is located. A plate spring 20 holds the trigger press in the upper position shown. The discharge flange 19 prevents the inward movement of the elastic wall segments 16 and thus the discharge of the downward movement of the cannula carrier 10.

The holding and release mechanism 14 is therefore a snapper with a lock in the present embodiment.

When the device is attached to a suitable part of the patient's body, i.e. glued, and connected to a device for delivering a solution of active ingredients, and when the injection is to be initiated, the patient presses down the pusher 18 against the pressure of the spring 20. This pushes the spreader flange 19 out of its seat inside the wall segments 16. The wall segments deflect inwards from the pressure exerted by the spiral spring 17 over the vulst onto the groin, and the needle carrier 10 including the needle 9 is pushed downwards by the spring 17 at high acceleration. The needle 9 is pushed through the adhesive layer 5 into the patient's body. The high acceleration results in the needle being blocked so that the patient does not feel pain.

The embodiment shown in Fig. 2 has a number of the same functional elements as those shown in Fig. 1. Some elements have merely a different shape, while other elements have different or additional functions.

A housing 21 has a hole 22 which in the present case has only one degree of diameter, namely the narrowing at its lower end to a passage for an injection tube 29. The housing is also fitted on its bottom with a layer of adhesive 24 which is formed continuously here. In a lateral extension 23 of the housing, a Luer access 26 is located which is connected to hole 22 by a channel 27. The upper and lower ends of the channel 27 in hole 22 are in two O-rings in corresponding ring nuts.

The cannula 29 is also located in a cannula 30 support, which is essentially cylindrical and has a channel 31 to connect the back of the cannula to the bore 22. Its mantle surface has a conical end formed by a cross-sectional extension upwards. The cannula 30 support is connected firmly via a ring-shaped crystal clear viewing element 33 to a cap 38 that covers the entire mechanism, which is movable downwards from the upper position shown in the figure and serves as the trigger head. The cap 38 has a viewing window 39 in its center.

On the housing surface, wall segments 36 are arranged around the rim of bore 22 and have axial projections at their upper edge, which reach below the conical base of the cannula holder 30. The wall segments 36 are elastic and together with the conical base of the cannula holder form a holding and release mechanism 34. By pressing the cap 38 with the finger, they are bent outwards until they release the cannula holder 30 at sufficient pressure. The finger pressure necessary to overcome the holding force pushes the needles into the patient's skin when the cannula holder 30 is released. The upper end of the needle holder 30 is narrowed and formed so that the elastic elements 36 are held downwards by a downward force which pushes the needles out of the canula.

The outer surface of the cap 38 is designed to be grasped with the fingers and retracted to its starting position. At its lower edge, the cap has an inward-facing protrusion 37 which, together with a corresponding section 35 of the casing, prevents the cap from being retracted beyond the starting point, thus enabling the needle to be fully retracted back into the casing after the infusion has been completed.

In the lower end position of cap 38 and cannula holder 30, the projections of the wall segments 36 are at the height of the view element 33 and adjacent to it. The wall segments 36 are highlighted in colour so that they are clearly visible from the view window 39 at this position, indicating that the cannula 29 is punctured.

Fig. 3a shows a device in which the housing 41 is very similar to that shown in Fig. 1 with bore 42, protrusion 43, adhesive layers 44 and 45, and with luer approach 46, channel 47 and O-rings 48 in the wall of bore 42. The cannula holder 50 with cannula 49 and connecting channel 51 and the wall segments 56 supporting it are the same as in Fig. 2.These 61 wedges are sliding in knots provided in the wall of the upper borehole, one of which is shown in Fig. 3b. The wedge has a vertical downward leg 62 and a ramp-shaped slanted leg 63. The two legs are connected at the bottom by a short horizontal piece 64. At their upper ends, a horizontal wedge 65,66 is attached to each. The right horizontal wedge 65, located on the vertical leg 62 above in the drawing, defines the position of the resting before the use of the device. The other horizontal wedge 66 above the carrying leg 63 defines the position of the resting after the use of the device.This retraction of the needle prevents both possible injury to the patient by tipping the needle during the removal and injury and thus infection of healthcare workers by the forward needle.

The device shown in Figure 4 has no pre-canonical trigger to be operated manually by the patient. The very flat housing 71 only about 10 mm high is closed upwards and has a concentric chamber 72 open downwards. It is also two-piece and has a section 73 inserted in the base area which at the same time forms a protruding part of the base area surrounding the passage. Between the main part of the housing 71 and the inserted section 73 there is a protective film 74 enclosing the chamber formed between the two parts. In the upper part of the housing there is a luer approach 76 connected by a channel 77 to the chamber 72.

An O-ring 78 is inserted into a corresponding circular nut at a concentric protrusion leading into the chamber from above.

A cannula 79 is housed in a cannula holder 80 which is essentially adapted to the shape of chamber 72. At its lower edge, the cannula holder 80 has a circular protrusion which enters into a corresponding ringnut of the housing, which together with the nut forms a snapper 81.

Near the upper edge of its cylindrical outer surface, the cannula holder has a circular ringnut in which an O-ring 82 is inserted, the two O-rings 78 and 82 creating a ring-shaped enclosed space between the cannula holder and the upper frontal surface of the chamber, connected only by the channel 77 to the Luer approach 76.

At its lower edge, the cantilever has two radially protruding pins 83 which are attached to the ends of two femoral springs 84 which are tensioned in such a way as to carry the cantilever downwards when released.

The function of this embodiment is as follows:

When the device is attached to a patient's body part, the connection to the conveyor system for the active solution (not shown) is made via the Luer approach. The conveyor pump creates pressure in the upper area of chamber 72. The force thereby exerted on the cannula carrier 80 is added to the force of the springs 84. As soon as the added force exceeds the holding force of the snapper 81, the cannula carrier moves downwards. The springs 84 now take over the propulsion of the cannula carrier. After an initial short distance, the inner upper edge of the cannula carrier reaches the O-ring 78 and thus gives way for the active solution to pass through the cannula 79 to the upper end of the cannula 79.

The device shown in Figure 5 is shown in two vertical cross-sections to make the details clearer. This device was designed to further reduce the height of the structure. Housing 91 is very flat, i.e. it is less than 10 mm high. A chamber 92 centrally located in the housing is again open and closed from below and upwards.

A cannula 99 is inserted into a cannula carrier 100 and otherwise moves freely in an elastic seal 101 at the bottom of the chamber.

The canister holder 100 consists essentially of a U-shaped element with the upper end of the canister containing the starting points for the transfer of the force of the canister 102 and the springs 102 are pre-tensioned to push the canister holder down with the canister 99 as soon as it is released.

The canister holder 100 is held in the upper resting position shown in Figure 5 by a slide 103; when the slide 103 is pushed to the right, it releases the canister holder 100 and the spring 102 can move the canister holder 100 downwards, including the canister 99, thus inserting the canister 99 into the patient's skin.

Claims (4)

1. A device for the introduction of an active substance solution into a patient with a housing (21, 41); means (24, 44, 45) for fastening the housing (21, 41) to the surface of the body of the patient; a cannula (29, 49) for the introduction of the active substance solution; an automatic advancer unit with a retaining and releasing mechanism (34, 57, 58) for propelling the cannula (29, 49) into the skin; a connecting channel (27, 31, 47, 51), which is open only in the inserted state of the cannula, between a connecting element (26, 46) for connection to a conveying unit for the active substance solution and the cannula (29, 49)    characterized in that

   - the connecting element (26, 46) is arranged on the outside of the housing (21, 41), and in that

   - means (38, 58) are provided for withdrawal of the cannula holder (30, 50) and the cannula (29, 49).
2. A device according to claim 1, characterized in that the retaining and releasing mechanism (34, 57, 58) has a spring-loaded catch (36, 56).
3. A device according to claim 1 or 2, characterized in that the retaining and releasing mechanism (34, 57, 58) has a releasing button (38, 58) with a viewing window (39, 59) to check the position of the cannula holder (30, 50) and the cannula (29, 49).
4. A device according to any one of foregoing claims 1 to 3, characterized in that the cannula holder (50) is provided with toes (61) on the side which are guided in a groove (62, 63, 64, 65, 66) of the housing (41).