FR2624378A1 - Microdelivery instillator - Google Patents

Abstract

The invention relates to a portable and disposable instillator device intended to deliver, with a low and extended delivery rate, medicinal or other fluids or solutions. The device 500 comprises a flat, deformable and inextensible reservoir bag 1, subjected to an outside pressure which causes it to empty through a drainage channel 5, which reaches, via a capillary flow-rate limiter device 400, 401 or 402, an instillation device such as a catheter or instillation needle 44. A constant pressure is exerted on the reservoir bag placed in an inextensible chamber, by virtue of an osmotic transfer of solvent coming from an attached reservoir.

Description

The invention relates to an apparatus making it possible to deliver, from a previously constituted reserve, fluids containing or not substances in solution or in suspension with a low and fairly constant flow rate over several hours or consecutive days. The device is
originally designed to deliver by instillation for medical or experimental purposes. natural or synthetic pharmacodynamic substances in living organisms but can be used for all purposes other than the transport and instillation of dynamic phanraco substances, for example but not limited to delivering aqueous or non-aqueous solvents, and possibly solutes present in these solvents, compatible with the materials used for the construction of the device. The device is autonomous in the sense that it does not require a constant supply of energy. This autonomy and its small footprint allow it to be used in particular, but not exclusively, as a portable permanent instillation system by patients receiving outpatient medical treatment. The relative simplicity of the device should make industrial manufacturing inexpensive, thus making it a single-use device. By an additional improvement not compulsory, the device can in certain versions receive a supplement allowing the constant flow to be transformed. in a flow rate with transient increases or decreases preprogrammed.

 The device is essentially characterized by a reservoir bag, the wall of which is made of a flexible material which is deformable but not extensible, capable of withstanding a relatively high mechanical stress, impregnable with the fluid contained therein delimiting an interior compartment with variable volume. by deformation, which interior compartment is connected in a leaktight manner with the exterior by a flexible or rigid non-crushable channel, carrying at its free exterior end a connection nozzle with any pipe making it possible to conduct the contents of the reservoir bag to such or such a desired destination, in particular inside a living organism. The deformation of the reservoir bag, and therefore its emptying, is obtained by inserting the bag in a pressure device developing a propellant pressure transmitted on the walls of the bag and therefore on the contents of the bag.

In this embodiment, the propellant pressure is supplied by raising the pressure of a fluid surrounding the reservoir bag, the
all enclosed in an inextensible enclosure through the wall of
which passes the evacuation channel of the contents of the reservoir bag.

The pressure rise is constant and self-regulating by the use of an osrrotic assembly, a flow limiter may be necessary at the outlet of the reservoir bag.

Figure 1 shows in profile an example of a tank bag
insert into the pressing system described in the text.

 FIG. 2 represents three embodiments (400, 401 and 402) of the flow-limiting device using a capillary duct, two of which (400 and 402) are shown in section and the third (401) in exploded view.

 Figure 3 shows in section the presser system (500) implementing the osrrotic transfer of a solvent.

 Continuously, the invention uses a reservoir bag made of flexible, deformable and non-extensible material, preferably transparent or translucent, impermeable to the fluid which it must contain, chemically inert and not releasing any substance capable of mixing with the contents of the bag or dissolve in it; its shape and dimensions are a function of the quantities of fluid to be stored as well as of the device providing the propellant pressure but the best results can be expected from a bag which can be emptied completely without the formation of folds or noticeable surface reliefs.

According to a first embodiment, the reservoir bag 1 is made up according to FIG. 1 of two flat sides united on their periphery 2 by welding, gluing, molding or any other procedure ensuring the tightness of the compartment thus delimited, or by molding in a single piece of
the whole flat bag. An orifice 3 provides for the passage through the wall of the bag by a flexible, non-squeezable tube 5 and the junction 4 between the tube 5 and the wall 1 of the bag is sealed, mechanically capable of withstanding the pressure at which the contents of the bag, and of a shape such that it can be used to position the bag in the pressure device described in the invention. The channel 5 is provided with a flow interruption device constituted by a clamp which can crush the tube 5 or any other valve type device operating by all or nothing and which is, as necessary, open during filling and feigned at the end of it. The tube 5 has at its end outside the bag a nozzle 20 allowing its connection with any other tube or channel
Inside the bag, the tube 5 and its end are arranged so as not to create by their presence an obstacle to the complete application one on the other of the sides of the bag, as well as to the free distribution of the contents of the bag therein under the action of propellant pressure to cause the emptying of the bag.

 For medical applications, the whole of the bag 1 and the drain tube 5 is constructed previous camp but in materials supporting the constraints of the sterilization necessary for this type of applications.

 The presser device (500) Figure 3: this device may not contain any nétaïl-ic part and implements the development of a pressure of osrrotic origin by transfer of a solvent through a membrane permeable exclusively to this solvent. The bag 1 containing the fluid to be dispensed is placed in a so-called "high pressure" enclosure, containing a concentrated solution of a solute soluble in the solvent to which the membrane is permeable. Pure solvent is placed in an adjacent enclosure, called a "low pressure" enclosure and in contact with the permeable membrane. The osnotic transfer of solvent from the compartment where it is pure to that containing the solute ensures the progressive rise in pressure in the high pressure enclosure, thus developing a pressure of osnotic origin on the content of the bag of fluid to be dispensed by deforming the wall. The osrrotic pressure thus developed obeys the law of V.NST'H2FF; the flow of solvent from the "low pressure" compartment to the "high pressure" compartment, therefore that of the fluid to be dispensed contained in the bag is, all other things being equal, a function of the difference in concentration of osnotically active solute between the two enclosures and the exchange surface through the membrane. Very high pressures can be obtained by this device.

According to one embodiment of the presser 500, the bag 1 - is placed in a "high pressure" enclosure 27 rehabilitating through its wall a sealed passage 28 for the channel 5. The enclosure 27 is integral with a second enclosure 29 or "low pressure" enclosure. The cavities of 27 and 29 are in cotirunication through a membrane 30 exclusively permeable to such or such solvent chosen as a function of its ability to cross this membrane 30 between the "high" and "low pressure" enclosures without altering the properties thereof. . The solvent 47 must be compatible with the material of the bag 1. The enclosure 30 furthermore has a rigid perforated wall 31 allowing free passage to the solvent and playing the role of mechanical protection barrier of the membrane 30. In 29 also is arranged a bag 37 impermeable to air and to solvent 47, the wall of which is extremely extensible and not modified by this solvent, and whose
the interior is canninized with the atmosphere by orifice 33.

The chambers 27 and 29 are provided with orifices 32 with leaktight closing and allowing the filling of 27 and 29 with the aid of the solvent. A solute 36 chosen for its extreme solubility in solvent 47 and its
impossibility to cross the membrane 30 is placed in 27 in a saturating quantity.

The flow limiting device, Figure 2: it consists of a capillary channel whose section must be sufficient not to create a filter effect with respect to particles in solution or in suspension in the fluid contained in the reservoir bag. This channel obeys
the law of Poiseuilles ie
flow rate = P 1-2. (3.14. R4 / 8. H. 1) where P 1-2 is the pressure difference at the ends of the channel, R4 is the radius of the pipe raised to the power 4, h is the viscosity of the circulating fluid and I la length of the channel. This device possibly having to be portable, sterilizable and disposable, it is important that its cost price is as low as possible. According to one embodiment (400) FIG. 2, it consists of a tube 12 made of metal or other material such as catheter, of constant section, and whose length can vary from a few tens of centimeters to several meters depending on the radius chosen for its section (a few fractions of a millimeter). In this case, the capillary wound on luisnyne is inserted into a suitable support device which can be but not exclusively ~ consisting of material molded around the capillary. According to another embodiment (402) Figure 2, the channel is formed by the confrontation a threaded rod 13 of threadable, moldable or other material, inserted into a rigid and smooth cylindrical tube or cavity 14 so that the crest l5 of the screw thread faced in a sealed manner against the smooth wall of the tube 14 separates each turn of turn of the next turn, thus forcing the circulating fluid entered under pressure at one end of the device to go through all the turns of the turn before reaching the other end: the capillary channel is then for section 16, that of the section of the thread and for length
I, the total length of the screw thread sculpted in the threaded rod. According to a third embodiment (401) in FIG. 2, the capillary channel is formed by the sealed confrontation of a part having a smooth and flat face 17 against a another piece 18 also planar but whose surface is depressed by a spiral groove 19, or rectilinear folded in a labyrinth or any other suitable geometry, and which can be obtained by engraving, molding, stamping or any process facilitating the manufacture and making it possible to moderate it the industrial cost: the capillary channel then has the length of that of the furrow 19 and for section that of the space delimited between the bottom and the sides of the furrow 19 engraved in 18 on the one hand, the smooth face of the opposite piece 17 d On the other hand, in the last two embodiments described above, the seal between the crests of the grooves and the tubular or flat face is ensured by forcing, gluing, polyrrérisante welding or not or any other suitable process.

In all of these embodiments, furthermore, nozzles 20 make it possible to connect the flow limiter to the outlet nozzle of the reservoir bag.

Procedure for use: the solute 36 being alone placed in the enclosure 27 in a suitable quantity, the bag 1 is filled in the enclosure 27 as described above by means of its evacuation channel 5, the orifices 32 being open. Channel 5 is then fertilized as already described. The enclosures 27 and 29 are then completely filled with osnotic solvent through the orifices 32. The enclosure 27 is then hermetically closed using the plug 34 itself crossed by a catheter 46 so that during the plugging the solvent 47 in excess in 27 drives any residual air out of 27. The catheter 46 is then sealed with a flar. The osnotic transfer of the solvent 47 from 29 to 27 begins as soon as the solute 36 is dissolved in the chamber 27. The progressive loss of solvent 47 undergone by 29 in favor of 27 is compensated by the entry of air into the deformable bag 37 without that it can be pressed against the membrane 30 due to the presence of the mechanical barrier 31. The excess solute 36 in the enclosure 27 ensures a constant concentration of the solution in the latter, and a constant osrrotic transfer of the solvent 47 from 29 to 27. This transfer compensates by volume in 27 for the equal volume outlet from the bag 1 of fluid to be instilled
The system can ensure a flow rate of a few fractions of milliliters per hour for several days, without variation due to the choice of a saturated concentration of solute 36. It is generally not useful to provide a flow limiter at the outlet of the bag 1 because of the possibility of regulating the flow rate by a judicious choice of the solvent 47 and of the solute 36 taking account of the solubility of the solute in the solvent 47 and of the exchange surface of the membrane 30.

Claims (5)

REVEIsDICAT ICNS  1. Micro-flow instillator characterized in that it consists (500) of a deformable and inextensible reservoir bag containing  the fluid or the solution to be instilled, delivering its content to the outside of the bag by means of a channel connected to a flow limiter characterized in that it consists of a non-filtering capillary channel and at the outlet of which the catheter channel, or the needle, is plugged in, and a pressure device characterized in that it consists of a rigid container containing the said reservoir bag and inside which a supply of solvent from to an osnotic transfer from a adjoining reservoir through a hemipenable membrane, ensures a pressure rise fully transmitted on the walls of the reservoir bag.  2. A microdbit instillator according to claim 1, characterized in that it comprises a reservoir bag made up of 2 flat sides united by their edges in a sealed manner, deformable, non-extensible, impregnable, the said bag 1 being provided with a channel filling and emptying 5 not obstructing the total application of the 2 sides against each other and having at its outer end a flow limiter (400, 401 or 402)  3. Micro-flow instillator according to claim 1, characterized in that it comprises a flow-limiting device consisting (400), of a capillary tube of diameter such that it does not exert a filtration action on the fluids or solutions circulating in it, sterilizable or not depending on the purpose pursued, the length of which can reach several tens of centimeters depending on the desired final flow rate, wound on it # rr ## ye, inserted in a molded support or not, provided at its ends with 'Nozzles 20 suitable for inserting said flow limiter between the reservoir bag channel and the catheter, or needle, to instillation.  4. Micro-flow instillator according to claim 1, characterized in that it comprises a flow-limiting device constituted (401 or 402), of a capillary channel resulting from the tight confrontation of a piece with smooth face against another piece whose face  smooth is engraved with a continuous groove terminated at its two ends by devices for connection to any channel conducting the fluid whose flow is to be limited.  5. Micro-flow instillator according to claim 1, characterized in that it implements (500), an osmotic pressure obtained by transfer of an aqueous or other solvent 47 through an osmotic exchange membrane 30 exclusively permeable to that -this, from a compartment 29 where the solvent 47 is pure or poor in solute and the progressive emptying of which leads to an entry of atirospheric air into an impregnable and expandable diverticulum 37 prevented by an obstacle 31 from accidentally being pressed against the membrane d osmotic exchange 30, to a second inextensible and rigid compartment 27 containing the reservoir bag 1 itself immersed in a saturation solution of a suitable solute 36 in the solvent 47, and the pressure of which is constantly increased by the arrive osmotic new amounts of solvent 47 is  fully transmitted to the contents of the tank bag 1 to be drained.