The present invention generally regards the controlled administration of substances through infusion devices implanted in the human body and more particularly has as its object an improved system for the controlled administration of a substance such as a drug, a hormone or a hormone complex and the like for which other administration modes result unsatisfactory or ineffective. More specifically, the invention is directed to such a system comprising an implanted infusion device provided with an improved docking group for reliably docking an ingestible substance carrier. The invention also relates with a special construction of the carrier.
A known system for the controlled administration of a substance from a human-body-implanted infusion device is disclosed in patent publication n. WO2012011132. This document discloses a system that comprises:
The refilling of the drug is devised to take place periodically through the ingestion of a carrier in the form of a capsule containing the desired substance. The disclosure is particularly suitable for insulin delivery, but it can be extended to other drugs as well. Once ingested by the patient, the carrier passively travels along the digestive system up to a certain intestinal loop, where the infusion group is implanted and where the carrier is magnetically docked by the docking group of the refill device.
The docking group presents two ferromagnetic elements enclosing a diametrically magnetized permanent magnet, separated by two non-ferromagnetic inserts. The magnet can rotate around its axis of 90° (thanks to a motor and a gear transmission) to switch from a deactivated condition to an activated one. The permanent magnet is oriented with respect to the two non-ferromagnetic elements so that, when the poles of the magnet are turned towards them, the field lines are shut from the north to the south poles on a short path through the close ferromagnetic material, with no magnetic field outside. By rotating the magnet by 90°, its poles are separated by the two non-ferromagnetic elements through which the field lines cannot pass. The preferential path then becomes the longer path through the ferromagnetic elements. This results in a corresponding polarization of the ends facing in the duodenal lumen.
The capsule consists of a cylindrical body that delimits an internal chamber for the substance storage. The capsule is made of a polymeric material, resistant to gastric acids, and is punchable by a needle. A metallic magnetizable structure, possibly covered with a polymeric coating avoiding the direct contact of the metal with the anatomical environment, is included in the carrier body, at a central portion thereof.
When the capsule reaches the duodenum and is close to the implanted device, it transmits a position signal to the control unit which activates the motor for the 90° rotation of the magnet. In this way, a magnetic field insists between the two ends of the pole to attract the arriving carrier, due to the metallic structure embedded on it. Once the capsule is perfectly docked, the control unit activates a linear motor able to eject a needle out to draw the substance from the carrier, with the help of a vacuum pump. The anchoring of the carrier to the device is allowed by the attraction force exerted by the docking circuit.
The present invention has its context in the observation of the above-mentioned system and the recognition of certain critical problems affecting its performance; this brought to the system for the controlled administration of a substance with an implanted infusion device and an improved docking of an ingestible substance carrier according to the invention, having the essential features of attached claim 1. A further aspect of the invention is in connection with a special configuration of the substance carrier, as per the contents of the relevant attached claims. Advantageous embodiments of the invention are defined by the other claims.
A first problem that was devised is in connection with the effectiveness and reliability of the needle punching action once the substance carrier is docked. The support at the central region of the carrier, and the needle punching occurring at a point displaced towards one end creates a torque opposing docking that may cause the rotation of the capsule with the risk of detachment. This problem is made more serious considering that the intensity of the magnetic attraction force is drastically reduced by the presence of tissue layers between the docking circuit and the substance carrier, thus increasing the risk of undesired detachment due to needle-induced rotation.
The docking at the central region can also result in a defective precision of the docking position, with consequent position uncertainty and thus possible unpredictable variations in the docking (and punching) behavior. Even when a docking system is used based on two magnetic units, which can capture two rings of the carrier once activated at the same time by the single permanent magnet, the attraction of the capsule may vary, depending on which ferromagnetic ring is attracted first. Possible scenarios include the docking of only a single unit of the magnetic cage with either of the rings, and a consequent seriously off-centered docking that may even prevent the punching itself or increase the above-mentioned detaching torque. The only way to prevent such problem could be to activate the docking system exactly at the moment in which the capsule is centered with respect to the magnetic docking cage. However, given the variability of the anatomic site and the peristaltic movements that drive the capsule advancement, this strategy is very fragile and poorly reliable.
The above described docking aspects have clearly a counterpart in the structure of the carrier, being it the element that has to fit with the docking system, a structure that in turn has to tackle problems not only in connection with a proper inclusion of the metallic elements, which should contribute to ensure an effective and reliable operation, improve safety by avoiding the release of metallic ions in the gastrointestinal environment, and be carried out with relatively simple capsule production steps. More generally speaking it is desirable that the capsule/carrier more successfully addresses fundamental issues such as the fabrication, assembly and filling in a reliable and certification-oriented way.
From a conceptual standpoint, the present invention then resides in a system that the docking group of which comprises two suitably distanced and independently controllable docking units, and in a capsule that correspondingly fits two ferromagnetic rings at positions displaced at respective axial ends of the capsule, housed and isolated in respective annular slots formed by a geometrical matching arrangement between axial end structures of a cylindrical tubular body (which creates a cavity for the substance), and two end caps. From this, and from its constructional embodiments and implementations, a number of important advantages ensue, related not only with a remarkably safer, more stable and more reliable operation of the system, but also with the structure and production of the carrier that can be made safer, easier to be fabricated, assembled and filled.
The characteristics and advantages of the system, docking group and substance carrier according to the present invention will be apparent from the following description of embodiments thereof, provided by way of non-limiting example with reference to the appended drawings wherein:
With reference to the above figures, and in particular for the moment to
Entering into further detail, starting from the capsule, and making reference to a first embodiment shown in
Each shell comprises an axial end structure 23a, 24a at the end opposite to the mutual shell engagement end. In this embodiment the axial end structure 23a of one of the shells, here the shell 23 represented in top position, can have a central hole 23c to allow substance filling during the assembly, as in the variant of
Two caps 25, 26 geometrically match with respective end structures 23a, 24a to hermetically close the slots 23b, 24b, isolating the rings 21, 22 and shaping the capsule with rounded ends favoring ingestion and traveling along the gastrointestinal tract. To this purpose the cap has a mushroom shape with a dome surfaced head 25a, 26a that joins with the cylindrical outer surface of the body without forming sharp edges, and a tubular skirt portion 25b, 26b that fits within respective slots 23b, 24b at the inside of the rings 21, 22 (the bore of the skirt engaging with the central peg of the end structure), to block the rings in a snug-fit fashion.
The structure of the cap 25 closing the end structure 23a of the shell 23 that may be open or closed, depending on the variant, changes correspondingly. For the open-end structure of
The assembly of the capsule body is a rather straightforward procedure that relies on the geometrical matching between the different components (self-explanatory
Firstly, the two carrier body components/shells 23, 24 are assembled together and sealed using a medical-grade adhesive (e.g. cyanoacrylates, cyclohexanone, etc.) or a direct bonding method (e.g. thermal welding with a laser), as in
The ferromagnetic rings 21, 22 are inserted into their dedicated slots 23b, 24b (
The other cap 25 is finally assembled analogously at the other end structure 23a, again to block ring 21 in the slot 23b, but with slightly different techniques dependent on the filling procedure. If the end structure 23a is open (
An alternative, second embodiment of a capsule 102 is shown in
In both the proposed embodiments, the ideal capsule diameter and length may be around 12 mm and 26 mm, respectively, which are suitable for ingestion and traveling in the gastrointestinal tract. However, different dimensions can be devised, by properly scaling the single components. As already mentioned, it is worth noting that the final carrier configuration obtained from the assembly of the mentioned parts presents no protruding edges, thus favoring ingestion and travel and safe interaction with tissues.
The carrier body and caps are made of known materials featured by resistance to gastrointestinal fluids and suitable mechanical properties to withstand peristalsis. At the same time, they allow punching through the dedicated needle, to enable substance (e.g. insulin) transfer from the ingestible carrier to the implanted reservoir, possibly a collapse of the internal capsule volume during aspiration (that facilitates the procedure) and biocompatibility. Finally, they guarantee e.g. insulin stability for a reasonable amount of time (at least 12-24 h). Constitutive materials with these properties can be selected among (but they are not limited to) thermoplastic polyurethanes, thermoplastic elastomers, polyvinyl chloride, medical silicones, polydimethylsiloxane. The carrier body and caps can be fabricated with injection molding, 3D printing, or casting. All the mentioned techniques are compatible with the proposed materials and suitable for future mass production of certified products. The internal surface of the capsule may be coated with other materials/molecules, to enhance the stability of the hormone/drug contained in it.
The rings are made of materials reactive to the magnetic field which can be selected among ferromagnetic materials, ferromagnetic alloys, composite polymer with magnetic fillers or permanent magnets.
Overall, the proposed design prevents the hormone/drug to enter in touch with the magnetic rings, thus avoiding clotting or other adverse effects in terms of hormone/drug stability. Furthermore, the overall carrier structure is conceived to avoid substance contact with air and biological environment and to guarantee proper sealing without any leakage.
Considering now in greater detail the magnetic docking group 1, with specific reference also to the remaining figures starting from
Each docking unit, with specific reference to
In this embodiment the unit further comprises one or more permanent magnets 16, with indicated N and S poles, possibly arranged in different configurations. While in
The rotation of the magnet, for the sake of simplicity here reference is made to the single magnet arrangement as in
As mentioned, in an aspect of the invention two separate docking units are placed at a proper distance to enable docking of the two carrier rings. The activation of the two docking units can be controlled independently, e.g. via respective actuators 17, 17′ and transmissions 18, 18′ as proposed in the embodiment shown in
In
As a subsequent step, the circuit of the upper unit 11 is activated to ensure stable docking of the capsule also on the upper/upstream ring 21 before punching (
Optionally, a mechanism allowing changing of the punching point can be implemented to minimize possible repeated damage to a specific point of the intestinal wall, which would thus have more time to recover/heal. A possible embodiment of this mechanism and relative operation is shown in
As mentioned, the independent/selective activation of the docking units can be driven also by alternative solutions to that of two actuators each driving its own docking unit. In fact, a single actuator, provided with an appropriate mechanism, may be used to drive both units, as per the embodiment of the docking group shown in
It will be easily understood that according to the present invention the advantages of a reliable/stable docking of the carrier and of a carrier design that facilitates the fabrication, assembly, and filling procedures are attained concurrently. In fact, the combined new arrangement of the docking/punching system and of the carrier allows stable and reliable docking, capsule punching, and thus the reservoir refilling with the target substance.
As far as the docking procedures are concerned, the possibility of a sequential switching by two independently driven and properly spaced units permits to have the capsule reliably docked with a correct and precise positioning. The punching can then occur in turn with a reliable success and, being the punching unit arranged between the docking units, without the risk that an overturning momentum may cause the undocking of the carrier before the filling is completed (or even started). The rings at the axial ends of the capsule are advantageously embodied in a structure that makes them safely unexposed to the gastrointestinal fluids and in general to the tissue environment, and at the same time provides a multi-component solution that guarantees a reliable fabrication and assembly of the carrier thus compatible with industrial production and suitable for future certification stages.
The present invention has been described with reference to preferred embodiments thereof. Variations and/or modifications can be brought to the invention without thereby departing from the scope of the invention itself as defined by the attached claims.
Number | Date | Country | Kind |
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102021000017999 | Jul 2021 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2022/056271 | 7/7/2022 | WO |