WO2000069493A1

WO2000069493A1 - Cannula/needle combination for a subcutaneous administration of a substance

Info

Publication number: WO2000069493A1
Application number: PCT/CH2000/000241
Authority: WO
Inventors: Fritz Kirchhofer; Jürg Steck
Original assignee: Disetronic Licensing Ag
Priority date: 1999-05-14
Filing date: 2000-05-01
Publication date: 2000-11-23
Also published as: JP2002543933A; DE19922350C1; AU3953800A

Abstract

The invention relates to a cannula/needle combination for a subcutaneous administration of a substance, in particular, a medical substance, for example insulin. Said combination comprises an injection needle (N) and a cannula (1) which surrounds the injection needle (N) and adapts to the form of said needle. The interior cross-section of the cannula (1) and cross-section of the needle (N) differ from one another in such a way that a hollow area (24) is formed between said cross-sections for conveying the substance.

Description

Cannula / needle combination for subcutaneous administration of an active ingredient

The invention relates to a cannula / needle combination for the subcutaneous administration of an active substance, in particular a medicinal active substance such as insulin. The cannula / needle combination is pierced through the skin. It is preferably a cannula / needle combination of a catheter head.

A catheter head with a cannula, as the invention also relates to it, is known from DE 198 21 723. The catheter head comprises a cannula housing with the cannula and a needle holder to be connected to the cannula housing with a feed for the active substance. The cannula protrudes from the cannula housing and is placed in a tissue. The cannula can be formed in one piece with the cannula housing or fastened or anchored to the cannula housing. It is flexible, in particular bendable. A passage channel to the cannula for the active substance is formed in the cannula housing. The cannula housing is shaped so that it sits flat on the tissue in which the cannula is placed, and it is prepared for fixation on the tissue.

A catheter for supplying the active substance to the cannula housing can be connected by means of a needle holder. A connecting needle is rigidly attached to the needle holder and is inserted into the through-channel of the cannula housing to establish the connection. The cannula and the cannula housing remain at the location of the fixation in and on the tissue, while the needle holder can be repeatedly connected to and detached from the cannula housing.

The cannula is placed in the tissue using a puncture needle. The puncture needle extends through the cannula housing and in particular through the cannula. The cannula hugs the needle. After the puncture needle together with the cannula Stuck under the skin and thereby the cannula is placed in the desired depth of penetration into the tissue, the puncture needle is withdrawn from the cannula and from the cannula housing. Depending on the design of the catheter head, the connecting needle is already in the through channel or is now inserted into the through channel in order to establish the connection between the cannula housing and the needle holder and thus also the connection of the connecting needle with the cannula placed in the tissue.

So that air is not conveyed through the cannula during the subsequent administration of the active substance, a so-called priming takes place before the piercing needle is inserted and the cannula is placed, in which the cavities of the catheter head, which lead to active substance in the later administration, are pre-filled with the active substance. In particular, the active ingredient is filled up to the tip of the puncture needle. For this purpose, the hollow puncture needle is provided with an opening at a suitable point in an area which does not protrude into the cannula, through which the active substance penetrates into the puncture needle up to the tip thereof during priming.

The user can see that the catheter head is filled with medicine up to the tip of the puncture needle as soon as medicine drips from the needle. Then the needle and needle are inserted under the skin and the catheter head is placed on the skin. If the patient pulls the needle out of the catheter head after this placement, only the cannula remains in the tissue.

A disadvantage of the needles of the prior art is that the opening reduces the stability of the needle. The needle may therefore buckle. This danger is all the more so when very thin needles, for example in a size 28G or thinner, are used. Stability is always a problem with thin needles, even without additional weakening due to a possible opening. However, the thinner the needle and the cannula, the more comfortable the puncture is felt by the user.

The object of the invention is to provide a cannula / needle combination for a puncture to create the skin, which can be thin and yet has improved kink stability. The combination is preferably easy to handle and can be produced economically.

This object is achieved durcji the subject of claim 1. Preferred embodiments are described by the features of the subclaims.

The invention relates to a cannula / needle combination for the subcutaneous administration of an active substance, in particular a medicinal active substance such as insulin. The combination comprises an injection needle and a cannula surrounding the injection needle, which is nestled onto the injection needle.

According to the invention, the inner cross section of the cannula and the outer cross section of the needle give way in combination, i.e. at least when the needle is inserted into the cannula. The cross-sectional shape of the needle and the cross-sectional shape of the hollow cross section of the cannula deviate from one another in such a way that space remains between the needle and the inner wall of the cannula through which active substance can be conveyed. Accordingly, the cannula is no longer tightly nestled over the full circumference of the needle, as in the combination according to the prior art, but only in some areas. Despite the needle inserted, there remains sufficient space within the hollow cross section of the cannula through which the active substance can be conveyed. In the case of priming in particular, the active substance can be conveyed through this cavity and then emerges at a front edge of the cannula.

In a preferred embodiment, the needle has an outer cross-section which deviates from the circular shape, while the inner cross-section of the cannula is circular, as in the case of conventional cannulas, so that space remains between the inner cross-section of the cannula and the outer cross-section of the needle, due to which active ingredient is primed the cannula end can run.

Instead of using a needle with a non-circular cross-section in combination with In a cannula with a circular cross section, a needle with a circular cross section can also be combined with a cannula which has a non-circular cross section.

Finally, both the needle and the cannula can each have an outer cross section or inner cross section that is not circular. For example, both cross sections can be longer in one direction of their cross section than in another direction. In the cannula / needle combination, however, it must then be ensured that there is still sufficient space for the active substance to pass through, which can be achieved in particular by the long axis of the outer cross section of the needle and the long axis of the inner cross section of the cannula not coinciding; the two long axes preferably point at an angle of approximately 90 ° to one another. The inner cross section of the cannula and / or the outer cross section of the needle can be oval, for example elliptical.

Alternatively or in support of such combinations of cannula and needle, the needle or the cannula or both the needle and the cannula can be provided with a longitudinally extending groove, indentation of the notch or flattened, so that space for the needle and the cannula inner wall the passage of the active ingredient to the tip of the cannula remains. A plurality of grooves or indentations or notches or flats or a total of several such shapes can also be provided on the respective circumference, which enable passage.

The outer cross section of the needle deviating from the inner cross section of the cannula in the formation of the cavity does not have to extend over the entire length of the needle, although this is preferred not least for reasons of simple manufacture.

A very particular advantage of the invention lies in the fact that the needle does not have to be hollow, since the active substance is conveyed between the outer cross section of the needle and the inner cross section of the cannula. In the case of a hollow needle that can also be used in principle in the combination according to the invention, however, a significantly higher kink stability is still guaranteed in any case, since there is no need to break through the hollow needle. This Breakthrough is, however, absolutely necessary in the case of the hollow needles according to the prior art, in order to be able to transport the active ingredient up to the tip of the cannula in a primer.

Further features and advantages of the invention result from the description of preferred exemplary embodiments with reference to the accompanying drawings. Show it:

1 shows a three-dimensional view of a catheter head with a cannula

/ Needle combination, Figure 2a-2c cross-sections through embodiments of cannula-needle combinations with non-circular outer needle cross-sections, Figure 3a-3c cross-sections through embodiments of cannula / needle combinations with non-circular inner cannula cross-sections, Figure 4 shows a longitudinal section of the catheter head according to Figure 1, and

Figure 5 shows a second embodiment of a catheter head in a longitudinal section.

FIG. 1 shows a catheter head with a cannula 1 projecting perpendicularly from an underside of the catheter head. The cannula 1 consists of a soft plastic material, in the exemplary embodiment Teflon. It encloses a puncture needle N tight, which extends through the catheter head perpendicular to its flat underside. The puncture needle N with the surrounding cannula 1, which is preferably stretched a little in cross section by the puncture needle N and thereby stretched, is also referred to below as a cannula / needle combination. The catheter head forms the front end of a catheter 5. The catheter 5 with the catheter head is set by a user, for example a diabetic himself. In this case, the puncture needle N and the cannula 1 are pierced vertically under the skin into the tissue and the catheter head with its underside is fixed or fastened flat on the skin. The fixation is done with a self-adhesive rondelle or a plaster. Such a rondelle enlarges the underside of the catheter head, which is available for adhesive purposes. If this underside itself already provides a sufficiently large adhesive surface, it is sufficient to form this underside as an adhesive surface. The puncture needle N is pulled out of the catheter head after the cannula 1 has been placed, so that only the thin, flexible, in particular bendable, cannula 1 remains in the tissue.

The catheter head has a cannula housing 2 which remains together with the cannula 1 at the puncture site and has the underside which serves to fix the catheter head. Furthermore, the catheter head has a needle holder 3, which forms the front end of the catheter 5. The cannula housing 2 and the needle holder 3 form a plug connection which can be repeatedly produced and released again.

The cannula / needle combinations of all the figures have in common that the needle N of the respective combination is designed as a non-hollow needle, the inner cross section of the cannula 1 and the outer cross section of the needle N differing in cross-sectional shape and or cross-sectional area from one another such that one or several spaces remain for the passage of an active ingredient, in particular for priming. In the case of the cannula / needle combination, an active ingredient does not run inside the needle when priming, but along the outer surface of the needle, i.e. in the space formed between the massive needle and the cannula inner cross-section to the tip of the cannula.

FIGS. 2a to 2c show cross sections through different embodiments of combinations of cannulas 1 and needles N, as can be used in the catheter heads of the figures, but also in other catheter heads or even without a catheter head.

In the embodiment shown in Figure 2a, the needle N has an oval cross section, while the inner cross section of the cannula 1 is circular before the insertion of the needle N, so that two spaces 24 remain after the insertion between the inner cross section of the cannula 1 and the outer cross section of the needle N. .

In the embodiment as shown in FIG. 2b, the needle N is provided with longitudinally extending grooves or indentations 26, the inner cross section of the cannula 1 still being circular. The grooves 26 of the needle N form together with the inner wall the cannula 1 or the cavities 24 for guiding the active ingredient.

In the embodiment shown in FIG. 2c, the needle N has flats 28. It has an angular cross section with chamfered edges, while the inner cross section of the cannula 1 is round before the needle N is inserted and even circular before the needle is inserted. In this embodiment, the active substance space 24 is therefore formed by the flattened flanks of the needle N and the inner wall of the cannula 1.

The secure seat of the needle N in the cannula 1 is achieved in all exemplary embodiments by the pressure which the cannula 1 experiences at the contact surfaces with the needle N.

FIGS. 3a to 3c show alternative embodiments of cannula / needle combinations according to the invention, a solid needle N each having a circular cross section being combined with a cannula 1 which has a non-circular inner cross section. The inner cross section of the cannula 1 can be oval, for example elliptical, as shown in FIG. 3a. It can be provided with longitudinally extending grooves 28, as shown in Figure 3 b, or can be designed with flats, as shown in Figure 3 c, so that there are cavities 24 between the needle N and the inner wall of the cannula for the passage of the active ingredient to the tip the cannula 1 result.

In addition to the illustrated embodiments, a combination of individual features of the illustrated embodiments with one another is also possible, for example two oval cross sections.

A preferred use of the cannula / needle combination, namely in a catheter head, is shown in FIGS. 1, 4 and 5.

The active ingredient, with reference to FIG. 4, is brought through the catheter 5 to the needle holder 3. It is passed through a connecting needle 4 accommodated in the needle holder 3 into a through-channel in the cannula housing 2, transported there further to the cannula 1 and passes through the cannula 1 to the desired location in the Tissue. An inlet and an adjoining area of the through-channel of the cannula housing 2 are enclosed by a cylindrical extension 6 which projects from a rear side of the cannula housing 2.

The catheter head shown has, in the assembled state, the overall shape of a semi-ovaloid with a flat underside 12, which ends rounded off towards the edge and slopes away from the skin and in the cannula housing 2 merges into an upper surface which is convex and concave in some areas. The cannula housing 2, on which the underside 12 lying on the skin is formed, has a rear disk-shaped region 11 and a front region 10 which is thickened in comparison, from the underside 12 of which the cannula 1 and from the rear of which the cylindrical extension 6 and covering it Project disk-shaped area 11 towards the rear in the direction of the needle holder 3 to be fed against it. The needle holder 3 has a symmetrical shape, i.e. its top and bottom are curved outwards in the same way; Furthermore, the needle holder 3 is symmetrical in plan view with respect to its central longitudinal axis.

The cylindrical extension 6, in cooperation with a guide sleeve 7 formed on the needle holder 3, serves as a guide means for positioning the connecting needle 4 relative to the inlet 9 and for correctly guiding the connecting needle 4 in the region of the through-channel adjoining the inlet. A part of the cannula housing 2 in the form of the cylindrical extension 6, which surrounds the through-channel, is thus guided out of the cannula housing 2 and can thus be used as a guide means when inserting the connecting needle 4. The cooperating guide means on the needle holder 3 is formed by the guide sleeve 7 which, in addition to its function as a guide means, at the same time protects the connecting needle 4 coaxially accommodated in it from damage; in addition, it protects a user from possible injuries due to a protruding needle, for example when palpating or in general when handled carelessly. The connecting needle 4 is protruded in its longitudinal direction by the guide sleeve 7.

In the representation of Figure 4, the guide sleeve 7 is completely on the cylindrical Extension 6 pushed on and abuts with its front edge against the back of the cannula housing 2, from which the cylindrical extension 6 protrudes. In this state, snap fingers engage behind corresponding projections in guide shafts. Unintentional loosening of the needle holder 3 is not possible.

The connecting needle 4 pierces a septum 8 arranged directly behind the inlet in the through-channel of the cylindrical extension 6. The septum 8 is designed such that it hermetically seals the through-channel of the cannula housing 2 even after multiple piercing. Immediately behind the septum 8, the through-channel has a dome 18 into which the connecting needle 4 protrudes. Adjoining the dome 18 is a channel section 19 which runs in a straight line in alignment with the connecting needle 4 and opens into a cavity 20 in the front region 10 of the cannula housing 2. The cannula 1 also opens into this cavity 20. The puncture needle N is passed through the cavity 20 at an angle, at right angles in the exemplary embodiment, to the connecting needle 4 and the channel section 19. The piercing needle N extends through the cannula housing 2 and points at an angle, in the exemplary embodiment at right angles, to its underside 12. In this arrangement, the piercing needle N is advantageously not guided through that part of the through-channel of the cannula housing 2 into which the connecting needle 4 is inserted.

With this arrangement, the piercing needle N does not have to be removed in order to be able to insert the connecting needle into the cannula housing. This is particularly advantageous for priming, in which the catheter head is filled as completely as possible with the active ingredient before the cannula 1 is placed.

The cannula 1 is designed as a thin tube with an f-like widening 21 at one end. The flange-like widening 21 is received in an annular disk-shaped recess in the cannula housing 2 and the cannula 1 is thereby anchored.

Opposite the cannula inlet, a further septum 22 is embedded in the cavity 20, which is the cavity 20, which is part of the through-channel of the cannula housing 2, after the Pulling out the needle N seals. The mode of action of the septum 22 is comparable to that of the septum 8. The shape of the cavity 20 is essentially cylindrical, the flange-like widening 21 of the cannula 1 and the septum 22 forming the opposite end faces of the cylindrical cavity 20 and between which the channel section 19 opens.

FIG. 5 shows a modified exemplary embodiment in which the puncture needle is inserted through the same through-channel of the cannula housing 2, into which the connecting needle 4 is to be inserted after the cannula 1 has been placed. With the exception of this arrangement of the puncture needle and the cannula 1, the catheter head of FIG. 5 corresponds to that described above, so that reference is made to its description.

Claims

Cannula / needle combination for subcutaneous administration of an active substance

1. cannula / needle combination for subcutaneous administration of an active ingredient, in particular a medical active ingredient such as insulin, the combination comprising: a) an injection needle (N) and b) a cannula surrounding the injection needle (N) and clinging to the injection needle ( 1) characterized in that c) the inner cross section of the cannula (1) and the outer cross section of the needle (N) differ from one another such that at least one cavity (24) is formed between them for the passage of the active substance.

2. cannula / needle combination according to claim 1, characterized in that the needle (N) has a cross-section deviating from the circular shape.

3. cannula / needle combination according to one of the preceding claims, characterized in that the needle (N) is provided with at least one longitudinally extending groove, indentation or notch (26).

4. cannula-needle combination according to one of the preceding claims, characterized in that the needle (N) has at least one longitudinally extending flattened portion (25).

5. cannula-Z needle combination according to one of the preceding claims, characterized in that the cannula (1) has a cross-section deviating from the circular shape.

6. cannula-Z needle combination according to one of the preceding claims, characterized in that the inner cross section of the cannula (1) is oval.

7. Cannula-Z needle combination according to one of the preceding claims, characterized in that the inner cross section of the cannula (1) is provided with at least one groove, indentation or notch (28) extending longitudinally up to a cannula end.

8. cannula / needle combination according to one of the preceding claims, characterized in that the inner cross section of the cannula (1) has at least one longitudinally extending flattened portion (28).

9. cannula-Z needle combination according to one of the preceding claims, characterized in that the needle (N) of the combination is designed as a non-hollow needle.