Device for supplying medicines

Abstract

A device for supplying medicines or the like to the body of man or beast has a container for preserving a medicine as well as means for changing the volume of the container. The container has an opening through which the medicine is ejected when the volume of the container is diminished. The invention is particularly characterized by the provision of another container operatively joined to the first-mentioned container and having a variable volume for varying the volume of the first-mentioned container. The change in volume of the other container is produced by gas or liquid particles diffused or entering through electrical fields or by electrolytical gas development within the container.

Description

This invention relates to a device for supplying medicines or the like to the body of man or beast, having a container for preserving a medicine as well as means for changing the volume of the container. The container has an opening through which the medicine is ejected when the volume of the container is diminished. The term "medicine" as used herein is intended to cover all substances which are used to improve, reinstate or maintain the health of a patient, such as for example, vitamins or hormones.

During many illnesses the patients must be provided with medicines for lengthy time periods, for example, insulin for diabetes, corticosteroides for rheumatic illnesses, cytostatics for cancer, blood pressure regulators or also sex hormones. Up to now the supply of these medicines to the body of the patient took place primarily either orally (by swallowing tablets) or by simple injection at certain time intervals. Thus this supply of medicines is a discontinuous one and is poorly adapted to the actual requirements of the patient. When the patient provides himself with the medicines, the correct dosage is not always provided. However, in case of many medicines a very precise dosage is most important, since an excess of the medicine or insufficient dosage can have detrimental effects. Thus, for example, an insufficient amount of insulin causes comadiabetics, while an excess produces a hypoglycaumic shock. A lack of precision in the dosing of insulin probably causes an inclination of diabetics to arteriosclerosis.

An object of the present invention is the provision of a device which is operable without the assistance of a doctor or the use of the patient for providing automatically for long time periods a comparatively precise dosage of a medicine.

Other objects will become apparent in the course of the following specification.

In the accomplishment of the objectives of the present invention it was found desirable to operatively combine with the container of the described type another container of variable volume serving as means for varying the volume of the medicine-carrying container. The change in volume of the second container is produced by gas or liquid particles diffused or entering through electrical fields or by electrolytical gas development within the container.

The regulation of the delivery of medicine out of the medicine-carrying container by a change in volume of another container operatively connected with the medicine-carrying container, makes it possible to provide with the simplest technical means an extremely precise dosage of the medicine being delivered for long time periods, since volume changes of a container as such can be continuously precisely produced in a simple manner and can be controlled. The changes in volume actuated by gas or liquid particles diffused or entering through electrical fields or by electrolytical gas development, is particularly advantageous since such flows have an extremely precise uniformity over long time periods, so that changes in volume of the container regulating the delivery of the medicine out of the medicine carrying container also have a high extent of continuity over long time periods. Furthermore, the dosage of the medicine can be made extremely fine, since the gas or liquid diffused or field currents or electrolytically produced gas currents causing the passage of medicine out of the medicine-carrying container can be kept extremely small by suitable shaping or measuring of the gas or liquid diffusion passage or of the electrolytic gas developer in the container.

In accordance with the present invention the medicine-carrying container can be made totally or partly of elastic material and means can be provided for transforming volume changes of the other container into a compressing force exerted upon the elastic material. The other container can press with at least a part of its walls directly upon the elastic material of the medicine-carrying container. For that purpose the medicine-carrying container is preferably placed within the main container or so arranged that at least the elastic part of the medicine-carrying container constitutes at the same time a part of the wall of the main container.

According to a preferred embodiment of the present invention the main container has a rigid casing the interior of which is divided by a separating wall into two chambers one of which has an outflow opening and is used to receive the medicine, while the second one has a diaphragm window through which gas or liquid particles can be diffused or entered by electrical field action or which can contain a gas producer for electrolytic gas separation, whereby the separating wall can be pushed into the first chamber due to an increase of gas or liquid in the second chamber. The diffusion or entry of gas or liquid particles into the second chamber preferably takes place either in the usual osmotic manner or in the electro-osmotic manner.

While the normal osmotic diffusion effect permits substantially only a dosage of the medicine to be used extending continuously over the entire duration of the treatment, the electro-osmotic effect as well as the electrolytic gas production in a further container permit a medicine dosage which can be operated or regulated from the outside to a certain extent, by setting currents of different strengths between electrodes required for producing the electro-osmotic effect or for electrolytic gas separation. The operation or regulation of the dosage can take place preferably by measure value signals which are obtained from or in the body of the patient and constitute a measure for the size of the body to be affected by the medicine.

The device of the present invention is paticularly suitable for implantation into the body of a patient. However, it can be obviously used outside of the body, for example, by being carried upon the surface of the body.

The invention will appear more clearly from the following detailed description, when taken in connection with the accompanying drawing showing by way of example only, preferred embodiments of the inventive idea.

In the drawing:

FIG. 1 is a section through an implantable device of the present invention operating according to normal osmose.

FIG. 2 is a section through an implantable device of the present invention operating according to electro-osmose.

FIG. 3 is a section through an implantable device of the present invention wherein changes in volume of the container actuating the medicine-carrying container are caused by gases produced electrolytically in the container.

The casings are indicated by the numeral 1 in the drawing. The casing 1 consists of a material which does not transmit liquid and is well adapted to tissue, for example, epoxide resin.

The interior of the casing 1 is divided by a diaphragm 2 into two separate chambers 3 and 4, whereby the chamber 3 is used for receiving a medicine, for example, insulin for treating diabetes, while chamber 4 serves for creating osmotic pressure as the result of which the diaphragm 2 is slowly pressed into the chamber 3 and thus by this extension presses the medicine located in the chamber 3 through an outflow opening 5 provided in the container. The diaphragm 2 consists of a liquid-tight material, preferably a plastic, and is elastic. It is also possible to additionally metallize the diaphragm 2 as well as the interior of the medicine-containing chamber 3 to provide greater impermeability against liquids and to prevent possible chemical reactions of the medicine with the material of the casing or diaphragm.

The liquid medicine driven through the opening 5 is transported through a thin tube 6 connected to the opening 5 to a suitable location in the body of the patient, for example, into the blood flow, and is there released. The free end of the tube 6 is preferably provided with a finely porous plug 7 which prevents return diffusion of the body liquid into the medicine-containing chamber 3 or an uncontrolled outflow of the medicine out of the chamber 3. The plug can consist of porous teflon or a hydrophylic material, such as cellulose, or an ion exchanging material. The width of the pores of the plug material should be less than 100.mu.m, preferably between 1 and 20.mu.m.

In the embodiment illustrated in FIG. 1 the creation of osmotic pressure in the chamber 4 takes place in a normal osmotic manner. For that purpose the wall of the chamber 4 is provided with a diaphragm window 8 consisting of a semi-permeable material which can transmit water or steam, and also small loose molecules or ions, but not the substance located within the chamber 4 and used to build up osmotic pressure in the chamber.

The window 8 can be either rigid or can be held by porous rigid supports preventing it from moving outwardly when pressure is increased. The material of the diaphragm can be either a hydrophobic material, for example, porous or also nonporous teflon, polyethylene or silicon, or the diaphragm can consist of a hydrophilic material, for example, cellulose, cellulose derivatives or ion exchangers. If porous teflon is used as the diaphragm material, then the width of its individual pores must be narrower than the width of the pores of the material of the plug located at the outlet of the medicine transmitting tube 6.

To make certain that there will be a uniform and fine outflow of the medicine out of the chamber 3, the steam pressure in the chamber 4 must be small relatively to steam pressure in the body liquid surrounding the casing 1. Furthermore, changes of steam pressure in the pressure chamber must remain small during the operational period, compared with the steam pressure difference relatively to body liquid. The dosage of the medicine is then determined by the extent of diffusion of water or steam in the chamber 4. The extent of transmission of the semipermeable window 8, its size and thickness are to be selected depending upon the desired dosage. A hygroscopic salt, such as magnesium-, zinc- or calcium chloride, is suggested as a substance with low steam partial pressure for the interior of the chamber 4.

If a material is selected for the diaphragm window which transmits ions, then the interior of the chamber 4 should be filled with a polyelectrolite or a gel. The osmotic pressure is then produced due to a so-called Donnan weight balance.

In the construction shown in FIG. 2 osmotic pressure in the chamber 4 is produced by an electro-osmotic effect. For that purpose the wall of the casing of the chamber 4 is provided with a diaphragm window 9 which is electrically charged and transmits ions. The window 9 is fixed between two electrodes 10 and 11 which produce a current through the window. The electrodes must be so polarized that counter ions move inwardly through the window to the solid ions, namely in the direction toward the chamber 4. If, for example, the window has cation exchange properties, then the electrode 10 must be polarized negatively and the electrode 11 must be polarized positively. When the electrodes 10 and 11 lie directly upon both sides of the window 9, they must be also made porous and filled with an electrolite, so that the electro-osmotic transportation of water through them can take place. Furthermore, the electrode 11 should be screened by a diaphragm 12 transmitting ions and suitable for tissue to avoid its contact with bodily tissue.

The electrodes 10, 11 can be supplied with outside current, for example, by a battery 13 through a potentiometer 14 which can be connected by outlet contacts 15 and 16 with the current connecting contacts 17 and 18 of the electrodes 10 and 11. If the electrodes consist of an inert material, such as platinum, then care must be taken that the feeding current should not exceed the amount of 1 mA/cm.sup.2, so that no gas development should take place (diffusion limit current).

However, the electrodes 10 and 11 can be advantageously so constructed that they themselves will supply the current. For that purpose an electrode consisting for example of zinc, cadmium, aluminum or glucose can be used as anode and as cathode can be a silver/silver chloride or an oxygen/carbon electrode. In case of a combination of a glucose electrode with an oxygen electrode, the glucose electrode which, for example, consists of platinum black or Raney-platinum-ruthenium, must be applied to the side facing the chamber 4 of the hydrophilic window constructed as anion exchanger (electrode 10). The oxygen electrode consists of porous charcoal and is located upon the outer side of the window 9 (electrode 11). Since the coal electrode is selective and reacts only with oxygen, the glucose is diffused without hindrance through the coal electrode and the window 9 to the non-selective precious metal electrode and can be reacted there. When a resistance 19 is connected, -- preferably a potentiometer for setting different cell currents, -- a current will flow between the electrodes.

The use of device devide of the present invention having a glucose-oxygen-electrode combination is particularly advantageous when as medicine insulin is to be supplied to diabetics. Since in such combination the current between the electrodes is also directly dependent from the glucose content of the tissue liquid of the patient, a more or less strong current corresponding to the height of the blood glucose mirror is produced in a time unit through the window, and thus more or less water is diffused in the same time period into the chamber 4 and thus due to a more or less quick filling of this space 4 a correspondingly strong or less strong insulin is transmitted through the opening 5 and tube 6 to the blood of the patient. Thus a device of this type carries out already by itself a certain regulating function with respect to an increased insulin delivery at a higher glucose mirror and a correspondingly weaker insulin delivery at a correspondingly lower glucose mirror.

However, even when other types of medicine are used it is possible to operate or regulate a corresponding adaptation of medicine delivery to the momentary requirement of the patient, by providing means which continuously supervise the body section to be influenced by the medicine and produce corresponding measuring signals which can be then used for operating or regulating the electrode current, for example, by correspondingly actuating the potentiometer 14 or 19. In case of a regulation as intended value is then used a normal value of the body size and the medicine delivery is regulated on the basis of body size signal-actual value-intended value deviation (over the current).

The amount of medicine which should be transmitted from the medicine container 3 into the tissue or blood of a patient corresponds to the amount of solution (water and ions) which is transmitted through the diaphragm window 8 or 9 into the chamber 4. In the embodiment of the invention illustrated in FIG. 2 this amount of solution and thus the delivered amount of medicine are determined directly by the strength of electro-osmotically actuating current. For example, per Faraday (96500 As) are transported by a cation exchange diaphragm at a current strength of 1 mA/cm.sup.2 50 mol of solution (corresponding to 90 gr.). Thus the delivery of 1 ml medicine requires about 100 As. If this amount of medicine is to be delivered within 24 hours, an electrode feeding current of about 1.25 mA is required.

In the embodiment shown in FIG. 3, as distinguished from those of FIGS. 1 and 2, the deviation of the diaphragm 2 does not take place by osmotic pressure in chamber 4, but a gas is produced electrolytically in chamber 4, which with increased volume moves the diaphragm 2 correspondingly into the medicine space 3. The electrolytic gas producer consists simply of an inert electrode 20 for gas separation, for example, a precious metal electrode (platinum), as well as a counter electrode 21 (silver/silver chloride or zinc electrode). Between the electrodes 20, 21 a fixed electrolite 22 is located. The current feeding of the electrodes takes place through the battery connections 23 and 24.

Contrary to the embodiments of FIGS. 1 and 2, the movable diaphragm 2 of FIG. 3 is not flat but is partially folded. However, this difference is only a variant of the diaphragm construction of FIGS. 1 and 2 and has no significance for the basic working principle of the device of the present invention.

As shown in FIGS. 1 and 2, two narrow conically outwardly extending bore holes 25, 26 are provided for filling medicine in the medicine containing chamber 3 and for emptying liquid or gas in the chamber 4, the holes being closed by spring valves 27 and 28.

For example, a precisely fitting also conical injection needle is introduced into this opening 25 or 26, which then opens automatically the valve 27 or 28 and by means of which the medicine container chamber 3 can be filled again or gas or liquid can be removed from the chamber 4.

During refilling with medicine necessarily small pressure differences take place in the chamber 3. To avoid an outflow of medicine from the outlet opening 5 or a suction of the body liquid, for example, a valve can be provided in the tube 6, which closes the outflow opening at the same time as the filling valve 27 is opened. Since the outflow opening is to be made as a narrow capillary, only small amounts of medicine which are within permissible tolerance limits can flow out during the refilling procedure due to variations in pressure.

Claims

I claim:

1. A device for supplying medicines to the body of man or beast, comprising means forming a first container of variable volume for containing a medicine and having an opening for delivery of medicine, means connected with the first-mentioned means and forming a second container of variable volume to vary the volume of the first-mentioned container, and means supplying volume varying means to the second mentioned container said volume varying means for said second container having a diaphragm window for receiving said volume varying means having two electrodes of different potentials and located on opposite sides of said diaphragm window and being embedded between said electrodes to provide a current or voltage supply for producing electrical fields so that fluid particles are transmitted into said second container in an electro-osmotic manner.

2. A device in accordance with claim 1, wherein said volume varying means comprise means electrolytically developing gas in the second-mentioned container.

3. A device in accordance with claim 2, wherein the first-mentioned and the second-mentioned means jointly constitute a rigid casing having a separating wall dividing the interior of said casing into the first-mentioned container and the second-mentioned container, said separating wall pressing into the first-mentioned container when the second-mentioned container receives an excess of said volume varying means.

4. A device in accordance with claim 1, wherein the diaphragm window of the second-mentioned container is semipermeable and consists of a substance selected from the class consisting of hydrophobic material, hydrophilic material, porous teflon, non-porous teflon, polyethylene, silicon, cellulose, cellulose derivatives and ion exchangers.

5. A device in accordance with claim 1, wherein said diaphragm window consists of electrically charged material transmitting water, steam and ions, said electrodes producing current of such polarity that water is transmitted into the second-mentioned casing in an electro-osmotic manner.

6. A device in accordance with claim 5, having means supplying a current to said electrodes and having a potentiometer varying the extent of this current.

7. A device in accordance with claim 5, wherein said electrodes are current producing electrodes and consist of a combination of a metallic electrode as anode of zinc, cadmium or aluminum with a silver/silver chloride or oxygen/carbon electrode as cathode or a combination of a selective oxygen electrode and a glucose electrode.

8. A device in accordance with claim 2, wherein means electrolytically developing gas comprise a precious metal inert electrode and a counter electrode selected from the class consisting of a silver/silver chloride electrode and a zinc electrode.

9. A device in accordance with claim 8, comprising an electronic steering and regulating device for steering and regulating the current between said electrodes depending upon measured value signals received from the body, said signals producing a measure for the size of the body to be influenced by the medicine.

10. A device in accordance with claim 3, wherein said casing consists of a substance impermeable to liquid and having at least an outer surface adaptable to tissue for transplanting it into a body.

11. A device in accordance with claim 1, comprising a plug closing said opening and consisting of a finely porous material.

12. A device in accordance with claim 11, wherein the pores of said material range between 1 .mu. and 20 .mu. and are less than 100 .mu..

13. A device for supplying medicines to the body of man or beast, comprising means forming a first container of variable volume for preserving a medicine and having an opening for delivery of medicine, means connected with the first-mentioned means and forming a second container of variable volume for varying the volume of the first container, and a device supplying volume varying means to the second container, said volume varying device comprising a diaphragm window for said second container, which consists of electrically charged material transmitting particles, such as of water, steam and ions, and further comprising at least two electrodes located on opposite sides of said diaphragm window, said diaphragm window being embedded between said electrodes, said electrodes comprising a current or voltage supply for producing current of such polarity between such electrodes, that particles, such as of water, are transmitted into the second container in an electro-osmotic manner.

14. A device in accordance with claim 13, wherein the diaphragm window of the second container is semipermeable and consists of a substance selected from the class consisting of hydrophilic material, such as cellulose, cellulose derivatives and ion exchangers.

15. A device in accordance with claim 13, said current or voltage supplying means comprising a device, such as a potentiometer, for varying the extent of current between electrodes.

16. A device in accordance with claim 13, wherein said electrodes are current producing electrodes and consist of a combination of a metallic electrode as anode of zinc, cadmium or aluminum with a silver/silver chloride or oxygen/carbon electrode as cathode.

17. A device in accordance with claim 13, wherein said electrodes are current producing electrodes and consist of a combination of a selective oxygen electrode and a glucose electrode.

18. A device in accordance with claim 13, wherein said electrode current or voltage supply comprises an electronic control device for controlling current between said electrodes depending upon measured value signals received from the body, said signals producing a measure for a variable quantity or parameter inside the body to be influenced by the medicine.

19. A device in accordance with claim 18, wherein said variable quantity or parameter is glucose inside said body and said medicine preserved by said first container is insulin.

20. A device in accordance with claim 13, comprising a plug closing said opening in said first container for delivery of medicine and consisting of a finely porous material, wherein the pores of said material range between 1 .mu.m and 20 .mu.m.