FR2621248A1 - Device which can be implanted within the body for repeated injection of precise doses of liquid medicinal substances - Google Patents

Abstract

This device is characterised in that it comprises a liquid resevoir 1 which is provided with means 7 making it possible to introduce therein, from outside the body, the medicinal substance to be injected, and which connects with a deformable injector 2 containing a needle 12 which can pass through its wall 9 many times under the effect of an external pressure and deliver a metered quantity of the medicinal liquid which it contains. Application to treating illnesses which require repeated injection over a protracted period, of liquid medicinal substances.

Description

 The present invention relates to a device which is implantable under the skin and which allows the repeated injection into the body of precise doses of medicinal substances in the liquid state.

 It is known that the treatment of certain patients, such as that of insulin-dependent diabetics, requires the administration of medicinal substances in amounts dosed by means of repeated transcutaneous injections at relatively short intervals - several times in 2 hours for example - for a period which can be very long and even equal to the life of the patient. Such treatment, which is necessarily painful, is also inconvenient and costly, in the sense that it requires very frequent appointments with a medical assistant.

 Also the tendency is currently to leave it to the patient to carry out these injections himself, and there are drug reservoirs which ensure the progressive distribution of the substances necessary for such treatments, the release of these doses being ensured by the pressure of a gas or by a complex pump external to the human body.

 However, in the first case, variations are observed over time in the pressure of the gas, and therefore in the drug distribution, which, obviously, is a major drawback. In the second case, the disadvantages result, essentially, from the fact that a complex electronic pump and an apparatus external to the body are used, with tubes passing through the cutaneous planes.

In addition, there is always a risk of obstruction of the tubes at their end by biological deposits
Also, the object of the present invention is to provide an injection device of the type specified above which does not have the drawbacks which have just been mentioned, and another object is that this device is inexpensive, reliable, easy to set up and simple enough to rule out any risk of misuse by the user, even if he is inexperienced.

 According to the invention, these objects, and others which will appear thereafter, are achieved by means of a device of the type specified above comprising a liquid reservoir which is provided with means making it possible to introduce therein, from the outside the organism, the drug substance to be injected and which is in communication with a deformable injector containing a needle capable of passing through its wall multiple times under the effect of an external pressure by delivering a metered quantity of the medicinal liquid which it contains.

 It is understood that, thanks to this device, transcutaneous pressure allows the needle of the injector, by deformation of its wall, to pass through the latter on numerous occasions and to diffuse each time in the body the metered amount of drug substance it needs, while the reservoir allows to refill the injector a lot of times. It should be noted, on the other hand, that any foreign body implanted in a living organism is rapidly surrounded by a thin fibrous membrane which isolates the foreign body, while the system according to the present invention makes it possible to cross this membrane and distribute the medicated liquid to ensure its distribution in the living organism concerned.

 Advantageously, the means specified above making it possible to introduce the drug substance to be injected into the injector reservoir, from outside the body, comprising a membrane which is capable of being pierced numerous times without substantially losing its impermeability and which is mounted on the edges of an orifice formed at the top of a rigid dome constituting a part of the envelope of the tank. This arrangement makes it possible to fill the reservoir several times, which considerably increases the duration of use of the device according to the invention.

 Advantageously, the membrane of the reservoir, as specified above, and / or the part of the wall of the injector crossed by its needle is made of a material which is called "HP silicone" and which is marketed by the company DOW CORNING. The use of this synthetic material is decisive, because it is biocompatible and its structure allows it to be crossed by a needle a very large number of times without changing its impermeability.

 According to a first advantageous embodiment of the device according to the present invention, its reservoir is connected to its injector, which is separated from it, by means of a tube with possible interposition of a valve preventing the return of the liquid to the reservoir, the latter preferably being constituted by the rigid dome mentioned above, at the top of which is mounted the liquid supply membrane specified above, and the base of which is closed by another deformable membrane. It is understood that a transcutaneous pressure on the latter makes it possible to pass a sufficient quantity of medicated liquid through the injector to fill it, however the reservoir can be filled itself, when the time comes, by puncture through the membrane of its rigid dome.

 Preferably, the injector of the device according to the present invention comprises a rigid base on which is fixed a hollow base pierced with orifices and in communication with the injection needle of the device, and a deformable dome which is mounted on the periphery of this base by enclosing the base and the needle, a compression spring surrounding the latter between the base and the wall of the deformable dome. Thus, a transcutaneous pressure on the latter, against the compression spring, causes the needle of the injector to pass through its dome, and the medicated liquid it contains to flow outward, and therefore to spread throughout the body.

 In addition, the deformable dome of this injector advantageously contains a rigid reinforcement interposed between its wall and the compression spring specified above and / or a stop integral with the needle of the injector.

This stop serves to limit the stroke of the needle and therefore the quantity of medicated liquid injected.

 In another advantageous embodiment of the device according to the present invention, its reservoir and its injector are combined in a single deformable capsule which is constituted by a perforated partition on either side of which are mounted the rigid dome specified above with its membrane for introducing the drug substance, and a deformable lower dome, the reservoir here being constituted by the space left free between the two dome in question.

 Preferably, the perforated partition of this device carries, on the side of its rigid upper dome, a cylinder which opens towards the latter, which has lateral orifices, and in which slides, with the interposition of a compression spring, a piston projecting towards the upper dome, and which extends towards the deformable lower dome, through the perforated partition, by the injection needle.

 It is understood that, in this compact embodiment, a pressure on the lower dome brings the piston and its cylinder closer to one another, which causes both the needle integral with the latter to pass through the wall of the dome, and the liquid from the cylinder to flow towards the needle, the lateral orifices provided in the wall of the cylinder being closed by the piston from the start of its movement. As for the supply of the reservoir, it takes place, as in the first embodiment, by transcutaneous puncture through the membrane which is stretched at the top of the rigid upper dome.

 Finally, the needle of this device advantageously enters a deformable block which is arranged between the perforated partition of the injector and its lower dome and which is preferably also made of HP silicone.

The description which follows, and which has no limiting character, will make it possible to understand clearly how the present invention can be put into practice. It should be read in conjunction with the accompanying drawings, among which
- Figure 1 shows a schematic sectional view of the injection device according to the present invention in a first embodiment; and
- Figure 2 shows, also in schematic sectional view, a second embodiment of this device.

 In its embodiment represented in FIG. 1, this injection device implantable under the skin comprises a reservoir and an injector which are designated as a whole by the references 1 and 2, respectively, and which are connected together by a thin flexible tubing 3.

 The subcutaneous cellular tissues in which this assembly is implanted have not been shown in the figures, nor has the patient's skin, but, in order to simplify the description which follows, it will be assumed that the skin extends above the devices shown in the figures, which gives meaning to expressions such as "upper", "lower", "up", "down", etc.

The reservoir 1 comprises a rigid dome 4 whose lower periphery is made integral by any appropriate means with a flexible and elastic base 5, therefore deformable, and which comprises at its apex an orifice 6 on which a membrane 7 is stretched. reasons which will be specified below, the latter must be capable of being pierced numerous times by a needle and, for this purpose, it is advantageously made of a well-defined biocompatible synthetic material which is known by the name of "silicone
HP "and which was created by the company DOW CORNING. As for the rigid dome 4, it can be made of a metal or any plastic material, however it may be a biocompatible material.

 The injector proper, 2, consists of a rigid base 8 which is made of metal or biocompatible plastic, like the rigid dome 4 of the tank 1 and su; the periphery of which is mounted upwards a flexible and deformable dome 9 capable of being pierced numerous times by a needle without becoming substantially permeable. Like the membrane 7 of the reservoir 1, this dome is advantageously made of HP silicone.

 In the volume formed inside the injector 2 between its flexible dome 9 and its rigid base 8, the latter carries a hollow base 10 laterally provided with orifices 11. A bevelled needle 12 extending upwards is fixed on the base 10 and it communicates with it, while a compression spring 13 surrounds it by resting, at its lower end, on the top of the base 10, and, at its upper end, on an annular reinforcement 15 pressed against the top of the dome 9 so as to release in its center the area located to the right of the needle 12. In addition, the latter is integral with a transverse stop 14 in the form of a ring whose diameter is less than that of the compression spring 13.Finally, a non-return valve 16 is mounted in the injector 2 at the location where the pipe 3 opens out; and this, so that it allows the flow of the medicated liquid through the latter from the reservoir 1 to the injector 2 and not vice versa.

 The operating mode of this device is as follows: when it is implanted under the patient's skin, the drug substance to be injected is introduced into the reservoir 1 by means of a syringe, not shown, the needle of which passes through the skin and the membrane 7. Any pressure on the deformable base 5 of the reservoir 1 drives the medicated liquid through the tubing 3 and the non-return valve 16 in the injector 2 until it is completely filled.

 It then suffices to press on its flexible dome 9 through the skin and the subcutaneous tissues so that the needle 12 crosses it and expels into the body the medicinal substance which comes from the volume enclosed by the breeze 8 and the dome 9 of the injector through the orifices 11 of its base 10 and the quantity of which injected, dosed precisely, depends on the value of this volume and on the position of the stop 12 which limits the penetration of the dome 9 onto needle 12.

 After releasing the pressure exerted on it, the injector 2 returns to its initial shape under the effect of the compression spring 13 by sucking liquid from the reservoir 1.

It is understood that this process can be repeated many times because the drilling of the membrane 7 and the dome 9 does not significantly affect their impermeability.

 In the real form: #sation of the injection device according to the indication which is r <presented in FIG. 2, the reservoir and the injector described above are grouped in a single and same capsule rliii is designated in its together by the reference 19 and qtli comprises two domes 2 () and 21 inverse one by comparison with the other and mounted by their base on a partition 22 provided with orifices 23. The upper dome 20 is rigid and it comprises its top a membrane 24 similar to that, 7, of FIG. 1, while the lower dome 21 is flexible and made, like the membrane 24, of a material capable of being pierced numerous times without becoming substantially permeable, which is the case with LISP silicone, as mentioned above.

 In the upper dome 20, a cylinder 25 which is open upwards is mounted by its base at the center of the partition 23, its side wall having radial orifices 26. A piston 27 can slide in this cylinder 25, with interposition of a compression spring 28, projecting upwards with its apex in the vicinity of the membrane 24. The bottom of the cylinder 25 communicates with an axial bevelled needle 29 which extends downwards, through the partition 22, in a block 30 in HP silicone, the height of which is substantially equal to the distance between the partition 22 and the bottom of the lower dome 21.

 The operating mode of this injector is analogous to that of the device of FIG. 1: the medicated liquid is injected, from the outside and through the membrane 24, into the interior of the capsule 19. A pressure on the latter compresses the flexible lower dome 21 and the deformable block 30 towards the needle 29 which passes through them to deliver beyond the wall of the assembly a determined quantity of medicinal substance originating from the interior of the cylinder 25 whose lateral orifices 26 are closed by the piston 27 aii start of its downward movement.

 It goes without saying that (# ('many modifications could be made to the embodiments' which have been described here by way of simple nonlimiting examples.

Thus the injector 2 of FIG. 1 and the capsule 19 of FIG. 2 could be implanted with a different orientation relative to the peall of the patient, and that their respective needles 12 and 29 could open out, not directly in the body, but in a tube leading to a vessel or to any body cavity.

 As for the dimensions of the device according to the invention, they depend on the intended use, and it will be sufficient to indicate that the volume of the reservoir 1 in FIG. 1 can be of the order of 5 to 20 cm3, however that of the injector can be of the order of 1 to 3 cm3.

Claims (10)

- CLAIMS 1. Device implantable in the body for the repeated injection of precise doses of liquid medicinal substances, characterized in that it comprises a liquid reservoir (1) which is provided with means (7, 2! F) allowing '' introduce therein, from outside the body, the drug substance to be injected and which is in communication with a deformable injector (2) containing a needle (12, 29) capable of crossing its wall (9, 21) of multiples times under the effect of an external pressure by delivering a metered amount of the medicated liquid it contains. 2. Device according to claim 1, characterized by the fact that said means for introducing into said reservoir (1), from inside the body, the medicinal substance to be injected comprises a membrane (7, 29+) which is liable to be pierced numerous times without appreciably losing its permeability and which is mounted on the edges of a household orifice at the top of a rigid dome (4, 20) constituting a part of the envelope of the tank (1). 3. Device according to claim 2, characterized in that said membrane (7, 24) and / or the part of the wall of the injector (2) through which said needle (12, 29) is made of biocompatible silicone. 4. Device according to any one of claims 1 to 3, characterized in that said reservoir (1) is connected to said injector (2), which is separated from it, by means of a tube (3) with possible interposition of 'A valve (16) preventing the return of the liquid to the reservoir (1). 5. Device according to claim 4, characterized in that said reservoir is constituted by said rigid dome (4) at the top of which is mounted said membrane (7) and whose base is closed by a deformable membrane (5).  r. 6. Device according to any one of claims 4 and 5, characterized in that said injector (2) comprises a rigid base (8) on which is fixed a hollow base (10) pierced with holes (11) and in communication with said needle (12) and a deformable dome (9) which is mounted on the periphery of this base (8) by enclosing the base (10) and the needle (11), a compression spring (13) surrounding this last between the base (10) and the wall of the deformable dome (9). 7. Device according to claim 6, characterized in that said deformable dome (9) further contains a rigid reinforcement interposed between its wall and said spring (13) etZou a stop (14) integral with the needle (12) the injector (2). 8. Device according to any one of claims 1 to 3, characterized in that said reservoir (1) and said injector (2) are combined in a single deformable capsule (19) which is constituted by a perforated partition (22 ) on either side of which are mounted said rigid dome (20) with its membrane (24) for introducing a medicinal substance, and a deformable lower dome (21). 9. Device according to claim 8, characterized in that said perforated partition (22) carries, on the side of the rigid upper dome (20), a cylinder (25) which opens towards the latter, which has lateral orifices (26), and in which slides, with the interposition of a compression spring (28), a piston (27) projecting towards said liquid drug introduction membrane (24), and which extends towards the lower dome deformable (21), through said perforated partition, by said needle (29). 10. Device according to any one of claims 8 and 9, characterized in that said needle (29) enters a deformable block (30) disposed between said perforated partition (22) and said deformable lower dome (21).